diff --git b/Documentation/ABI/testing/debugfs-aufs b/Documentation/ABI/testing/debugfs-aufs new file mode 100644 index 0000000..99642d1 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-aufs @@ -0,0 +1,50 @@ +What: /debug/aufs/si_/ +Date: March 2009 +Contact: J. R. Okajima +Description: + Under /debug/aufs, a directory named si_ is created + per aufs mount, where is a unique id generated + internally. + +What: /debug/aufs/si_/plink +Date: Apr 2013 +Contact: J. R. Okajima +Description: + It has three lines and shows the information about the + pseudo-link. The first line is a single number + representing a number of buckets. The second line is a + number of pseudo-links per buckets (separated by a + blank). The last line is a single number representing a + total number of psedo-links. + When the aufs mount option 'noplink' is specified, it + will show "1\n0\n0\n". + +What: /debug/aufs/si_/xib +Date: March 2009 +Contact: J. R. Okajima +Description: + It shows the consumed blocks by xib (External Inode Number + Bitmap), its block size and file size. + When the aufs mount option 'noxino' is specified, it + will be empty. About XINO files, see the aufs manual. + +What: /debug/aufs/si_/xino0, xino1 ... xinoN +Date: March 2009 +Contact: J. R. Okajima +Description: + It shows the consumed blocks by xino (External Inode Number + Translation Table), its link count, block size and file + size. + When the aufs mount option 'noxino' is specified, it + will be empty. About XINO files, see the aufs manual. + +What: /debug/aufs/si_/xigen +Date: March 2009 +Contact: J. R. Okajima +Description: + It shows the consumed blocks by xigen (External Inode + Generation Table), its block size and file size. + If CONFIG_AUFS_EXPORT is disabled, this entry will not + be created. + When the aufs mount option 'noxino' is specified, it + will be empty. About XINO files, see the aufs manual. diff --git b/Documentation/ABI/testing/sysfs-aufs b/Documentation/ABI/testing/sysfs-aufs new file mode 100644 index 0000000..82f9518 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-aufs @@ -0,0 +1,31 @@ +What: /sys/fs/aufs/si_/ +Date: March 2009 +Contact: J. R. Okajima +Description: + Under /sys/fs/aufs, a directory named si_ is created + per aufs mount, where is a unique id generated + internally. + +What: /sys/fs/aufs/si_/br0, br1 ... brN +Date: March 2009 +Contact: J. R. Okajima +Description: + It shows the abolute path of a member directory (which + is called branch) in aufs, and its permission. + +What: /sys/fs/aufs/si_/brid0, brid1 ... bridN +Date: July 2013 +Contact: J. R. Okajima +Description: + It shows the id of a member directory (which is called + branch) in aufs. + +What: /sys/fs/aufs/si_/xi_path +Date: March 2009 +Contact: J. R. Okajima +Description: + It shows the abolute path of XINO (External Inode Number + Bitmap, Translation Table and Generation Table) file + even if it is the default path. + When the aufs mount option 'noxino' is specified, it + will be empty. About XINO files, see the aufs manual. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index d9c171c..f08f4cc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4311,6 +4311,9 @@ HIGHMEM regardless of setting of CONFIG_HIGHPTE. + uuid_debug= (Boolean) whether to enable debugging of TuxOnIce's + uuid support. + vdso= [X86,SH] On X86_32, this is an alias for vdso32=. Otherwise: diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt index 05e2822..6aa5a88 100644 --- a/Documentation/block/bfq-iosched.txt +++ b/Documentation/block/bfq-iosched.txt @@ -11,21 +11,32 @@ controllers), BFQ's main features are: groups (switching back to time distribution when needed to keep throughput high). +If bfq-mq patches have been applied, then the following three +instances of BFQ are available (otherwise only the first instance): +- bfq: mainline version of BFQ, for blk-mq +- bfq-mq: development version of BFQ for blk-mq; this version contains + also all latest features and fixes not yet landed in mainline, plus many + safety checks +- bfq-sq: BFQ for legacy blk; also this version contains latest features + and fixes, as well as safety checks + In its default configuration, BFQ privileges latency over throughput. So, when needed for achieving a lower latency, BFQ builds schedules that may lead to a lower throughput. If your main or only goal, for a given device, is to achieve the maximum-possible throughput at all times, then do switch off all low-latency heuristics -for that device, by setting low_latency to 0. Full details in Section 3. +for that device, by setting low_latency to 0. See Section 3 for +details on how to configure BFQ for the desired tradeoff between +latency and throughput, or on how to maximize throughput. On average CPUs, the current version of BFQ can handle devices performing at most ~30K IOPS; at most ~50 KIOPS on faster CPUs. As a reference, 30-50 KIOPS correspond to very high bandwidths with sequential I/O (e.g., 8-12 GB/s if I/O requests are 256 KB large), and -to 120-200 MB/s with 4KB random I/O. BFQ has not yet been tested on -multi-queue devices. +to 120-200 MB/s with 4KB random I/O. BFQ is currently being tested on +multi-queue devices too. -The table of contents follow. Impatients can just jump to Section 3. +The table of contents follows. Impatients can just jump to Section 3. CONTENTS @@ -33,7 +44,7 @@ CONTENTS 1-1 Personal systems 1-2 Server systems 2. How does BFQ work? -3. What are BFQ's tunable? +3. What are BFQ's tunables and how to properly configure BFQ? 4. BFQ group scheduling 4-1 Service guarantees provided 4-2 Interface @@ -145,19 +156,28 @@ plus a lot of code, are borrowed from CFQ. contrast, BFQ may idle the device for a short time interval, giving the process the chance to go on being served if it issues a new request in time. Device idling typically boosts the - throughput on rotational devices, if processes do synchronous - and sequential I/O. In addition, under BFQ, device idling is - also instrumental in guaranteeing the desired throughput - fraction to processes issuing sync requests (see the description - of the slice_idle tunable in this document, or [1, 2], for more - details). + throughput on rotational devices and on non-queueing flash-based + devices, if processes do synchronous and sequential I/O. In + addition, under BFQ, device idling is also instrumental in + guaranteeing the desired throughput fraction to processes + issuing sync requests (see the description of the slice_idle + tunable in this document, or [1, 2], for more details). - With respect to idling for service guarantees, if several processes are competing for the device at the same time, but - all processes (and groups, after the following commit) have - the same weight, then BFQ guarantees the expected throughput - distribution without ever idling the device. Throughput is - thus as high as possible in this common scenario. + all processes and groups have the same weight, then BFQ + guarantees the expected throughput distribution without ever + idling the device. Throughput is thus as high as possible in + this common scenario. + + - On flash-based storage with internal queueing of commands + (typically NCQ), device idling happens to be always detrimental + for throughput. So, with these devices, BFQ performs idling + only when strictly needed for service guarantees, i.e., for + guaranteeing low latency or fairness. In these cases, overall + throughput may be sub-optimal. No solution currently exists to + provide both strong service guarantees and optimal throughput + on devices with internal queueing. - If low-latency mode is enabled (default configuration), BFQ executes some special heuristics to detect interactive and soft @@ -191,10 +211,7 @@ plus a lot of code, are borrowed from CFQ. - Queues are scheduled according to a variant of WF2Q+, named B-WF2Q+, and implemented using an augmented rb-tree to preserve an O(log N) overall complexity. See [2] for more details. B-WF2Q+ is - also ready for hierarchical scheduling. However, for a cleaner - logical breakdown, the code that enables and completes - hierarchical support is provided in the next commit, which focuses - exactly on this feature. + also ready for hierarchical scheduling, details in Section 4. - B-WF2Q+ guarantees a tight deviation with respect to an ideal, perfectly fair, and smooth service. In particular, B-WF2Q+ @@ -249,13 +266,24 @@ plus a lot of code, are borrowed from CFQ. the Idle class, to prevent it from starving. -3. What are BFQ's tunable? -========================== +3. What are BFQ's tunables and how to properly configure BFQ? +============================================================= -The tunables back_seek-max, back_seek_penalty, fifo_expire_async and -fifo_expire_sync below are the same as in CFQ. Their description is -just copied from that for CFQ. Some considerations in the description -of slice_idle are copied from CFQ too. +Most BFQ tunables affect service guarantees (basically latency and +fairness) and throughput. For full details on how to choose the +desired tradeoff between service guarantees and throughput, see the +parameters slice_idle, strict_guarantees and low_latency. For details +on how to maximise throughput, see slice_idle, timeout_sync and +max_budget. The other performance-related parameters have been +inherited from, and have been preserved mostly for compatibility with +CFQ. So far, no performance improvement has been reported after +changing the latter parameters in BFQ. + +In particular, the tunables back_seek-max, back_seek_penalty, +fifo_expire_async and fifo_expire_sync below are the same as in +CFQ. Their description is just copied from that for CFQ. Some +considerations in the description of slice_idle are copied from CFQ +too. per-process ioprio and weight ----------------------------- @@ -285,15 +313,17 @@ number of seeks and see improved throughput. Setting slice_idle to 0 will remove all the idling on queues and one should see an overall improved throughput on faster storage devices -like multiple SATA/SAS disks in hardware RAID configuration. +like multiple SATA/SAS disks in hardware RAID configuration, as well +as flash-based storage with internal command queueing (and +parallelism). So depending on storage and workload, it might be useful to set slice_idle=0. In general for SATA/SAS disks and software RAID of SATA/SAS disks keeping slice_idle enabled should be useful. For any configurations where there are multiple spindles behind single LUN -(Host based hardware RAID controller or for storage arrays), setting -slice_idle=0 might end up in better throughput and acceptable -latencies. +(Host based hardware RAID controller or for storage arrays), or with +flash-based fast storage, setting slice_idle=0 might end up in better +throughput and acceptable latencies. Idling is however necessary to have service guarantees enforced in case of differentiated weights or differentiated I/O-request lengths. @@ -312,13 +342,14 @@ There is an important flipside for idling: apart from the above cases where it is beneficial also for throughput, idling can severely impact throughput. One important case is random workload. Because of this issue, BFQ tends to avoid idling as much as possible, when it is not -beneficial also for throughput. As a consequence of this behavior, and -of further issues described for the strict_guarantees tunable, -short-term service guarantees may be occasionally violated. And, in -some cases, these guarantees may be more important than guaranteeing -maximum throughput. For example, in video playing/streaming, a very -low drop rate may be more important than maximum throughput. In these -cases, consider setting the strict_guarantees parameter. +beneficial also for throughput (as detailed in Section 2). As a +consequence of this behavior, and of further issues described for the +strict_guarantees tunable, short-term service guarantees may be +occasionally violated. And, in some cases, these guarantees may be +more important than guaranteeing maximum throughput. For example, in +video playing/streaming, a very low drop rate may be more important +than maximum throughput. In these cases, consider setting the +strict_guarantees parameter. strict_guarantees ----------------- @@ -420,6 +451,13 @@ The default value is 0, which enables auto-tuning: BFQ sets max_budget to the maximum number of sectors that can be served during timeout_sync, according to the estimated peak rate. +For specific devices, some users have occasionally reported to have +reached a higher throughput by setting max_budget explicitly, i.e., by +setting max_budget to a higher value than 0. In particular, they have +set max_budget to higher values than those to which BFQ would have set +it with auto-tuning. An alternative way to achieve this goal is to +just increase the value of timeout_sync, leaving max_budget equal to 0. + weights ------- @@ -510,10 +548,12 @@ To get proportional sharing of bandwidth with BFQ for a given device, BFQ must of course be the active scheduler for that device. Within each group directory, the names of the files associated with -BFQ-specific cgroup parameters and stats begin with the "bfq." -prefix. So, with cgroups-v1 or cgroups-v2, the full prefix for -BFQ-specific files is "blkio.bfq." or "io.bfq." For example, the group -parameter to set the weight of a group with BFQ is blkio.bfq.weight +BFQ-specific cgroup parameters and stats begin with the "bfq.", +"bfq-sq." or "bfq-mq." prefix, depending on which instance of bfq you +want to use. So, with cgroups-v1 or cgroups-v2, the full prefix for +BFQ-specific files is "blkio.bfqX." or "io.bfqX.", where X can be "" +(i.e., null string), "-sq" or "-mq". For example, the group parameter +to set the weight of a group with the mainline BFQ is blkio.bfq.weight or io.bfq.weight. Parameters to set @@ -521,7 +561,7 @@ Parameters to set For each group, there is only the following parameter to set. -weight (namely blkio.bfq.weight or io.bfq-weight): the weight of the +weight (namely blkio.bfqX.weight or io.bfqX.weight): the weight of the group inside its parent. Available values: 1..10000 (default 100). The linear mapping between ioprio and weights, described at the beginning of the tunable section, is still valid, but all weights higher than diff --git b/Documentation/filesystems/aufs/README b/Documentation/filesystems/aufs/README new file mode 100644 index 0000000..fa82b63 --- /dev/null +++ b/Documentation/filesystems/aufs/README @@ -0,0 +1,393 @@ + +Aufs4 -- advanced multi layered unification filesystem version 4.x +http://aufs.sf.net +Junjiro R. Okajima + + +0. Introduction +---------------------------------------- +In the early days, aufs was entirely re-designed and re-implemented +Unionfs Version 1.x series. Adding many original ideas, approaches, +improvements and implementations, it becomes totally different from +Unionfs while keeping the basic features. +Recently, Unionfs Version 2.x series begin taking some of the same +approaches to aufs1's. +Unionfs is being developed by Professor Erez Zadok at Stony Brook +University and his team. + +Aufs4 supports linux-4.0 and later, and for linux-3.x series try aufs3. +If you want older kernel version support, try aufs2-2.6.git or +aufs2-standalone.git repository, aufs1 from CVS on SourceForge. + +Note: it becomes clear that "Aufs was rejected. Let's give it up." + According to Christoph Hellwig, linux rejects all union-type + filesystems but UnionMount. + + +PS. Al Viro seems have a plan to merge aufs as well as overlayfs and + UnionMount, and he pointed out an issue around a directory mutex + lock and aufs addressed it. But it is still unsure whether aufs will + be merged (or any other union solution). + + + +1. Features +---------------------------------------- +- unite several directories into a single virtual filesystem. The member + directory is called as a branch. +- you can specify the permission flags to the branch, which are 'readonly', + 'readwrite' and 'whiteout-able.' +- by upper writable branch, internal copyup and whiteout, files/dirs on + readonly branch are modifiable logically. +- dynamic branch manipulation, add, del. +- etc... + +Also there are many enhancements in aufs, such as: +- test only the highest one for the directory permission (dirperm1) +- copyup on open (coo=) +- 'move' policy for copy-up between two writable branches, after + checking free space. +- xattr, acl +- readdir(3) in userspace. +- keep inode number by external inode number table +- keep the timestamps of file/dir in internal copyup operation +- seekable directory, supporting NFS readdir. +- whiteout is hardlinked in order to reduce the consumption of inodes + on branch +- do not copyup, nor create a whiteout when it is unnecessary +- revert a single systemcall when an error occurs in aufs +- remount interface instead of ioctl +- maintain /etc/mtab by an external command, /sbin/mount.aufs. +- loopback mounted filesystem as a branch +- kernel thread for removing the dir who has a plenty of whiteouts +- support copyup sparse file (a file which has a 'hole' in it) +- default permission flags for branches +- selectable permission flags for ro branch, whether whiteout can + exist or not +- export via NFS. +- support /fs/aufs and /aufs. +- support multiple writable branches, some policies to select one + among multiple writable branches. +- a new semantics for link(2) and rename(2) to support multiple + writable branches. +- no glibc changes are required. +- pseudo hardlink (hardlink over branches) +- allow a direct access manually to a file on branch, e.g. bypassing aufs. + including NFS or remote filesystem branch. +- userspace wrapper for pathconf(3)/fpathconf(3) with _PC_LINK_MAX. +- and more... + +Currently these features are dropped temporary from aufs4. +See design/08plan.txt in detail. +- nested mount, i.e. aufs as readonly no-whiteout branch of another aufs + (robr) +- statistics of aufs thread (/sys/fs/aufs/stat) + +Features or just an idea in the future (see also design/*.txt), +- reorder the branch index without del/re-add. +- permanent xino files for NFSD +- an option for refreshing the opened files after add/del branches +- light version, without branch manipulation. (unnecessary?) +- copyup in userspace +- inotify in userspace +- readv/writev + + +2. Download +---------------------------------------- +There are three GIT trees for aufs4, aufs4-linux.git, +aufs4-standalone.git, and aufs-util.git. Note that there is no "4" in +"aufs-util.git." +While the aufs-util is always necessary, you need either of aufs4-linux +or aufs4-standalone. + +The aufs4-linux tree includes the whole linux mainline GIT tree, +git://git.kernel.org/.../torvalds/linux.git. +And you cannot select CONFIG_AUFS_FS=m for this version, eg. you cannot +build aufs4 as an external kernel module. +Several extra patches are not included in this tree. Only +aufs4-standalone tree contains them. They are described in the later +section "Configuration and Compilation." + +On the other hand, the aufs4-standalone tree has only aufs source files +and necessary patches, and you can select CONFIG_AUFS_FS=m. +But you need to apply all aufs patches manually. + +You will find GIT branches whose name is in form of "aufs4.x" where "x" +represents the linux kernel version, "linux-4.x". For instance, +"aufs4.0" is for linux-4.0. For latest "linux-4.x-rcN", use +"aufs4.x-rcN" branch. + +o aufs4-linux tree +$ git clone --reference /your/linux/git/tree \ + git://github.com/sfjro/aufs4-linux.git aufs4-linux.git +- if you don't have linux GIT tree, then remove "--reference ..." +$ cd aufs4-linux.git +$ git checkout origin/aufs4.0 + +Or You may want to directly git-pull aufs into your linux GIT tree, and +leave the patch-work to GIT. +$ cd /your/linux/git/tree +$ git remote add aufs4 git://github.com/sfjro/aufs4-linux.git +$ git fetch aufs4 +$ git checkout -b my4.0 v4.0 +$ (add your local change...) +$ git pull aufs4 aufs4.0 +- now you have v4.0 + your_changes + aufs4.0 in you my4.0 branch. +- you may need to solve some conflicts between your_changes and + aufs4.0. in this case, git-rerere is recommended so that you can + solve the similar conflicts automatically when you upgrade to 4.1 or + later in the future. + +o aufs4-standalone tree +$ git clone git://github.com/sfjro/aufs4-standalone.git aufs4-standalone.git +$ cd aufs4-standalone.git +$ git checkout origin/aufs4.0 + +o aufs-util tree +$ git clone git://git.code.sf.net/p/aufs/aufs-util aufs-util.git +- note that the public aufs-util.git is on SourceForge instead of + GitHUB. +$ cd aufs-util.git +$ git checkout origin/aufs4.0 + +Note: The 4.x-rcN branch is to be used with `rc' kernel versions ONLY. +The minor version number, 'x' in '4.x', of aufs may not always +follow the minor version number of the kernel. +Because changes in the kernel that cause the use of a new +minor version number do not always require changes to aufs-util. + +Since aufs-util has its own minor version number, you may not be +able to find a GIT branch in aufs-util for your kernel's +exact minor version number. +In this case, you should git-checkout the branch for the +nearest lower number. + +For (an unreleased) example: +If you are using "linux-4.10" and the "aufs4.10" branch +does not exist in aufs-util repository, then "aufs4.9", "aufs4.8" +or something numerically smaller is the branch for your kernel. + +Also you can view all branches by + $ git branch -a + + +3. Configuration and Compilation +---------------------------------------- +Make sure you have git-checkout'ed the correct branch. + +For aufs4-linux tree, +- enable CONFIG_AUFS_FS. +- set other aufs configurations if necessary. + +For aufs4-standalone tree, +There are several ways to build. + +1. +- apply ./aufs4-kbuild.patch to your kernel source files. +- apply ./aufs4-base.patch too. +- apply ./aufs4-mmap.patch too. +- apply ./aufs4-standalone.patch too, if you have a plan to set + CONFIG_AUFS_FS=m. otherwise you don't need ./aufs4-standalone.patch. +- copy ./{Documentation,fs,include/uapi/linux/aufs_type.h} files to your + kernel source tree. Never copy $PWD/include/uapi/linux/Kbuild. +- enable CONFIG_AUFS_FS, you can select either + =m or =y. +- and build your kernel as usual. +- install the built kernel. + Note: Since linux-3.9, every filesystem module requires an alias + "fs-". You should make sure that "fs-aufs" is listed in your + modules.aliases file if you set CONFIG_AUFS_FS=m. +- install the header files too by "make headers_install" to the + directory where you specify. By default, it is $PWD/usr. + "make help" shows a brief note for headers_install. +- and reboot your system. + +2. +- module only (CONFIG_AUFS_FS=m). +- apply ./aufs4-base.patch to your kernel source files. +- apply ./aufs4-mmap.patch too. +- apply ./aufs4-standalone.patch too. +- build your kernel, don't forget "make headers_install", and reboot. +- edit ./config.mk and set other aufs configurations if necessary. + Note: You should read $PWD/fs/aufs/Kconfig carefully which describes + every aufs configurations. +- build the module by simple "make". + Note: Since linux-3.9, every filesystem module requires an alias + "fs-". You should make sure that "fs-aufs" is listed in your + modules.aliases file. +- you can specify ${KDIR} make variable which points to your kernel + source tree. +- install the files + + run "make install" to install the aufs module, or copy the built + $PWD/aufs.ko to /lib/modules/... and run depmod -a (or reboot simply). + + run "make install_headers" (instead of headers_install) to install + the modified aufs header file (you can specify DESTDIR which is + available in aufs standalone version's Makefile only), or copy + $PWD/usr/include/linux/aufs_type.h to /usr/include/linux or wherever + you like manually. By default, the target directory is $PWD/usr. +- no need to apply aufs4-kbuild.patch, nor copying source files to your + kernel source tree. + +Note: The header file aufs_type.h is necessary to build aufs-util + as well as "make headers_install" in the kernel source tree. + headers_install is subject to be forgotten, but it is essentially + necessary, not only for building aufs-util. + You may not meet problems without headers_install in some older + version though. + +And then, +- read README in aufs-util, build and install it +- note that your distribution may contain an obsoleted version of + aufs_type.h in /usr/include/linux or something. When you build aufs + utilities, make sure that your compiler refers the correct aufs header + file which is built by "make headers_install." +- if you want to use readdir(3) in userspace or pathconf(3) wrapper, + then run "make install_ulib" too. And refer to the aufs manual in + detail. + +There several other patches in aufs4-standalone.git. They are all +optional. When you meet some problems, they will help you. +- aufs4-loopback.patch + Supports a nested loopback mount in a branch-fs. This patch is + unnecessary until aufs produces a message like "you may want to try + another patch for loopback file". +- vfs-ino.patch + Modifies a system global kernel internal function get_next_ino() in + order to stop assigning 0 for an inode-number. Not directly related to + aufs, but recommended generally. +- tmpfs-idr.patch + Keeps the tmpfs inode number as the lowest value. Effective to reduce + the size of aufs XINO files for tmpfs branch. Also it prevents the + duplication of inode number, which is important for backup tools and + other utilities. When you find aufs XINO files for tmpfs branch + growing too much, try this patch. +- lockdep-debug.patch + Because aufs is not only an ordinary filesystem (callee of VFS), but + also a caller of VFS functions for branch filesystems, subclassing of + the internal locks for LOCKDEP is necessary. LOCKDEP is a debugging + feature of linux kernel. If you enable CONFIG_LOCKDEP, then you will + need to apply this debug patch to expand several constant values. + If don't know what LOCKDEP, then you don't have apply this patch. + + +4. Usage +---------------------------------------- +At first, make sure aufs-util are installed, and please read the aufs +manual, aufs.5 in aufs-util.git tree. +$ man -l aufs.5 + +And then, +$ mkdir /tmp/rw /tmp/aufs +# mount -t aufs -o br=/tmp/rw:${HOME} none /tmp/aufs + +Here is another example. The result is equivalent. +# mount -t aufs -o br=/tmp/rw=rw:${HOME}=ro none /tmp/aufs + Or +# mount -t aufs -o br:/tmp/rw none /tmp/aufs +# mount -o remount,append:${HOME} /tmp/aufs + +Then, you can see whole tree of your home dir through /tmp/aufs. If +you modify a file under /tmp/aufs, the one on your home directory is +not affected, instead the same named file will be newly created under +/tmp/rw. And all of your modification to a file will be applied to +the one under /tmp/rw. This is called the file based Copy on Write +(COW) method. +Aufs mount options are described in aufs.5. +If you run chroot or something and make your aufs as a root directory, +then you need to customize the shutdown script. See the aufs manual in +detail. + +Additionally, there are some sample usages of aufs which are a +diskless system with network booting, and LiveCD over NFS. +See sample dir in CVS tree on SourceForge. + + +5. Contact +---------------------------------------- +When you have any problems or strange behaviour in aufs, please let me +know with: +- /proc/mounts (instead of the output of mount(8)) +- /sys/module/aufs/* +- /sys/fs/aufs/* (if you have them) +- /debug/aufs/* (if you have them) +- linux kernel version + if your kernel is not plain, for example modified by distributor, + the url where i can download its source is necessary too. +- aufs version which was printed at loading the module or booting the + system, instead of the date you downloaded. +- configuration (define/undefine CONFIG_AUFS_xxx) +- kernel configuration or /proc/config.gz (if you have it) +- behaviour which you think to be incorrect +- actual operation, reproducible one is better +- mailto: aufs-users at lists.sourceforge.net + +Usually, I don't watch the Public Areas(Bugs, Support Requests, Patches, +and Feature Requests) on SourceForge. Please join and write to +aufs-users ML. + + +6. Acknowledgements +---------------------------------------- +Thanks to everyone who have tried and are using aufs, whoever +have reported a bug or any feedback. + +Especially donators: +Tomas Matejicek(slax.org) made a donation (much more than once). + Since Apr 2010, Tomas M (the author of Slax and Linux Live + scripts) is making "doubling" donations. + Unfortunately I cannot list all of the donators, but I really + appreciate. + It ends Aug 2010, but the ordinary donation URL is still available. + +Dai Itasaka made a donation (2007/8). +Chuck Smith made a donation (2008/4, 10 and 12). +Henk Schoneveld made a donation (2008/9). +Chih-Wei Huang, ASUS, CTC donated Eee PC 4G (2008/10). +Francois Dupoux made a donation (2008/11). +Bruno Cesar Ribas and Luis Carlos Erpen de Bona, C3SL serves public + aufs2 GIT tree (2009/2). +William Grant made a donation (2009/3). +Patrick Lane made a donation (2009/4). +The Mail Archive (mail-archive.com) made donations (2009/5). +Nippy Networks (Ed Wildgoose) made a donation (2009/7). +New Dream Network, LLC (www.dreamhost.com) made a donation (2009/11). +Pavel Pronskiy made a donation (2011/2). +Iridium and Inmarsat satellite phone retailer (www.mailasail.com), Nippy + Networks (Ed Wildgoose) made a donation for hardware (2011/3). +Max Lekomcev (DOM-TV project) made a donation (2011/7, 12, 2012/3, 6 and +11). +Sam Liddicott made a donation (2011/9). +Era Scarecrow made a donation (2013/4). +Bor Ratajc made a donation (2013/4). +Alessandro Gorreta made a donation (2013/4). +POIRETTE Marc made a donation (2013/4). +Alessandro Gorreta made a donation (2013/4). +lauri kasvandik made a donation (2013/5). +"pemasu from Finland" made a donation (2013/7). +The Parted Magic Project made a donation (2013/9 and 11). +Pavel Barta made a donation (2013/10). +Nikolay Pertsev made a donation (2014/5). +James B made a donation (2014/7 and 2015/7). +Stefano Di Biase made a donation (2014/8). +Daniel Epellei made a donation (2015/1). +OmegaPhil made a donation (2016/1). +Tomasz Szewczyk made a donation (2016/4). +James Burry made a donation (2016/12). + +Thank you very much. +Donations are always, including future donations, very important and +helpful for me to keep on developing aufs. + + +7. +---------------------------------------- +If you are an experienced user, no explanation is needed. Aufs is +just a linux filesystem. + + +Enjoy! + +# Local variables: ; +# mode: text; +# End: ; diff --git b/Documentation/filesystems/aufs/design/01intro.txt b/Documentation/filesystems/aufs/design/01intro.txt new file mode 100644 index 0000000..ae16191 --- /dev/null +++ b/Documentation/filesystems/aufs/design/01intro.txt @@ -0,0 +1,171 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Introduction +---------------------------------------- + +aufs [ei ju: ef es] | /ey-yoo-ef-es/ | [a u f s] +1. abbrev. for "advanced multi-layered unification filesystem". +2. abbrev. for "another unionfs". +3. abbrev. for "auf das" in German which means "on the" in English. + Ex. "Butter aufs Brot"(G) means "butter onto bread"(E). + But "Filesystem aufs Filesystem" is hard to understand. +4. abbrev. for "African Urban Fashion Show". + +AUFS is a filesystem with features: +- multi layered stackable unification filesystem, the member directory + is called as a branch. +- branch permission and attribute, 'readonly', 'real-readonly', + 'readwrite', 'whiteout-able', 'link-able whiteout', etc. and their + combination. +- internal "file copy-on-write". +- logical deletion, whiteout. +- dynamic branch manipulation, adding, deleting and changing permission. +- allow bypassing aufs, user's direct branch access. +- external inode number translation table and bitmap which maintains the + persistent aufs inode number. +- seekable directory, including NFS readdir. +- file mapping, mmap and sharing pages. +- pseudo-link, hardlink over branches. +- loopback mounted filesystem as a branch. +- several policies to select one among multiple writable branches. +- revert a single systemcall when an error occurs in aufs. +- and more... + + +Multi Layered Stackable Unification Filesystem +---------------------------------------------------------------------- +Most people already knows what it is. +It is a filesystem which unifies several directories and provides a +merged single directory. When users access a file, the access will be +passed/re-directed/converted (sorry, I am not sure which English word is +correct) to the real file on the member filesystem. The member +filesystem is called 'lower filesystem' or 'branch' and has a mode +'readonly' and 'readwrite.' And the deletion for a file on the lower +readonly branch is handled by creating 'whiteout' on the upper writable +branch. + +On LKML, there have been discussions about UnionMount (Jan Blunck, +Bharata B Rao and Valerie Aurora) and Unionfs (Erez Zadok). They took +different approaches to implement the merged-view. +The former tries putting it into VFS, and the latter implements as a +separate filesystem. +(If I misunderstand about these implementations, please let me know and +I shall correct it. Because it is a long time ago when I read their +source files last time). + +UnionMount's approach will be able to small, but may be hard to share +branches between several UnionMount since the whiteout in it is +implemented in the inode on branch filesystem and always +shared. According to Bharata's post, readdir does not seems to be +finished yet. +There are several missing features known in this implementations such as +- for users, the inode number may change silently. eg. copy-up. +- link(2) may break by copy-up. +- read(2) may get an obsoleted filedata (fstat(2) too). +- fcntl(F_SETLK) may be broken by copy-up. +- unnecessary copy-up may happen, for example mmap(MAP_PRIVATE) after + open(O_RDWR). + +In linux-3.18, "overlay" filesystem (formerly known as "overlayfs") was +merged into mainline. This is another implementation of UnionMount as a +separated filesystem. All the limitations and known problems which +UnionMount are equally inherited to "overlay" filesystem. + +Unionfs has a longer history. When I started implementing a stackable +filesystem (Aug 2005), it already existed. It has virtual super_block, +inode, dentry and file objects and they have an array pointing lower +same kind objects. After contributing many patches for Unionfs, I +re-started my project AUFS (Jun 2006). + +In AUFS, the structure of filesystem resembles to Unionfs, but I +implemented my own ideas, approaches and enhancements and it became +totally different one. + +Comparing DM snapshot and fs based implementation +- the number of bytes to be copied between devices is much smaller. +- the type of filesystem must be one and only. +- the fs must be writable, no readonly fs, even for the lower original + device. so the compression fs will not be usable. but if we use + loopback mount, we may address this issue. + for instance, + mount /cdrom/squashfs.img /sq + losetup /sq/ext2.img + losetup /somewhere/cow + dmsetup "snapshot /dev/loop0 /dev/loop1 ..." +- it will be difficult (or needs more operations) to extract the + difference between the original device and COW. +- DM snapshot-merge may help a lot when users try merging. in the + fs-layer union, users will use rsync(1). + +You may want to read my old paper "Filesystems in LiveCD" +(http://aufs.sourceforge.net/aufs2/report/sq/sq.pdf). + + +Several characters/aspects/persona of aufs +---------------------------------------------------------------------- + +Aufs has several characters, aspects or persona. +1. a filesystem, callee of VFS helper +2. sub-VFS, caller of VFS helper for branches +3. a virtual filesystem which maintains persistent inode number +4. reader/writer of files on branches such like an application + +1. Callee of VFS Helper +As an ordinary linux filesystem, aufs is a callee of VFS. For instance, +unlink(2) from an application reaches sys_unlink() kernel function and +then vfs_unlink() is called. vfs_unlink() is one of VFS helper and it +calls filesystem specific unlink operation. Actually aufs implements the +unlink operation but it behaves like a redirector. + +2. Caller of VFS Helper for Branches +aufs_unlink() passes the unlink request to the branch filesystem as if +it were called from VFS. So the called unlink operation of the branch +filesystem acts as usual. As a caller of VFS helper, aufs should handle +every necessary pre/post operation for the branch filesystem. +- acquire the lock for the parent dir on a branch +- lookup in a branch +- revalidate dentry on a branch +- mnt_want_write() for a branch +- vfs_unlink() for a branch +- mnt_drop_write() for a branch +- release the lock on a branch + +3. Persistent Inode Number +One of the most important issue for a filesystem is to maintain inode +numbers. This is particularly important to support exporting a +filesystem via NFS. Aufs is a virtual filesystem which doesn't have a +backend block device for its own. But some storage is necessary to +keep and maintain the inode numbers. It may be a large space and may not +suit to keep in memory. Aufs rents some space from its first writable +branch filesystem (by default) and creates file(s) on it. These files +are created by aufs internally and removed soon (currently) keeping +opened. +Note: Because these files are removed, they are totally gone after + unmounting aufs. It means the inode numbers are not persistent + across unmount or reboot. I have a plan to make them really + persistent which will be important for aufs on NFS server. + +4. Read/Write Files Internally (copy-on-write) +Because a branch can be readonly, when you write a file on it, aufs will +"copy-up" it to the upper writable branch internally. And then write the +originally requested thing to the file. Generally kernel doesn't +open/read/write file actively. In aufs, even a single write may cause a +internal "file copy". This behaviour is very similar to cp(1) command. + +Some people may think it is better to pass such work to user space +helper, instead of doing in kernel space. Actually I am still thinking +about it. But currently I have implemented it in kernel space. diff --git b/Documentation/filesystems/aufs/design/02struct.txt b/Documentation/filesystems/aufs/design/02struct.txt new file mode 100644 index 0000000..1d1ccde --- /dev/null +++ b/Documentation/filesystems/aufs/design/02struct.txt @@ -0,0 +1,258 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Basic Aufs Internal Structure + +Superblock/Inode/Dentry/File Objects +---------------------------------------------------------------------- +As like an ordinary filesystem, aufs has its own +superblock/inode/dentry/file objects. All these objects have a +dynamically allocated array and store the same kind of pointers to the +lower filesystem, branch. +For example, when you build a union with one readwrite branch and one +readonly, mounted /au, /rw and /ro respectively. +- /au = /rw + /ro +- /ro/fileA exists but /rw/fileA + +Aufs lookup operation finds /ro/fileA and gets dentry for that. These +pointers are stored in a aufs dentry. The array in aufs dentry will be, +- [0] = NULL (because /rw/fileA doesn't exist) +- [1] = /ro/fileA + +This style of an array is essentially same to the aufs +superblock/inode/dentry/file objects. + +Because aufs supports manipulating branches, ie. add/delete/change +branches dynamically, these objects has its own generation. When +branches are changed, the generation in aufs superblock is +incremented. And a generation in other object are compared when it is +accessed. When a generation in other objects are obsoleted, aufs +refreshes the internal array. + + +Superblock +---------------------------------------------------------------------- +Additionally aufs superblock has some data for policies to select one +among multiple writable branches, XIB files, pseudo-links and kobject. +See below in detail. +About the policies which supports copy-down a directory, see +wbr_policy.txt too. + + +Branch and XINO(External Inode Number Translation Table) +---------------------------------------------------------------------- +Every branch has its own xino (external inode number translation table) +file. The xino file is created and unlinked by aufs internally. When two +members of a union exist on the same filesystem, they share the single +xino file. +The struct of a xino file is simple, just a sequence of aufs inode +numbers which is indexed by the lower inode number. +In the above sample, assume the inode number of /ro/fileA is i111 and +aufs assigns the inode number i999 for fileA. Then aufs writes 999 as +4(8) bytes at 111 * 4(8) bytes offset in the xino file. + +When the inode numbers are not contiguous, the xino file will be sparse +which has a hole in it and doesn't consume as much disk space as it +might appear. If your branch filesystem consumes disk space for such +holes, then you should specify 'xino=' option at mounting aufs. + +Aufs has a mount option to free the disk blocks for such holes in XINO +files on tmpfs or ramdisk. But it is not so effective actually. If you +meet a problem of disk shortage due to XINO files, then you should try +"tmpfs-ino.patch" (and "vfs-ino.patch" too) in aufs4-standalone.git. +The patch localizes the assignment inumbers per tmpfs-mount and avoid +the holes in XINO files. + +Also a writable branch has three kinds of "whiteout bases". All these +are existed when the branch is joined to aufs, and their names are +whiteout-ed doubly, so that users will never see their names in aufs +hierarchy. +1. a regular file which will be hardlinked to all whiteouts. +2. a directory to store a pseudo-link. +3. a directory to store an "orphan"-ed file temporary. + +1. Whiteout Base + When you remove a file on a readonly branch, aufs handles it as a + logical deletion and creates a whiteout on the upper writable branch + as a hardlink of this file in order not to consume inode on the + writable branch. +2. Pseudo-link Dir + See below, Pseudo-link. +3. Step-Parent Dir + When "fileC" exists on the lower readonly branch only and it is + opened and removed with its parent dir, and then user writes + something into it, then aufs copies-up fileC to this + directory. Because there is no other dir to store fileC. After + creating a file under this dir, the file is unlinked. + +Because aufs supports manipulating branches, ie. add/delete/change +dynamically, a branch has its own id. When the branch order changes, +aufs finds the new index by searching the branch id. + + +Pseudo-link +---------------------------------------------------------------------- +Assume "fileA" exists on the lower readonly branch only and it is +hardlinked to "fileB" on the branch. When you write something to fileA, +aufs copies-up it to the upper writable branch. Additionally aufs +creates a hardlink under the Pseudo-link Directory of the writable +branch. The inode of a pseudo-link is kept in aufs super_block as a +simple list. If fileB is read after unlinking fileA, aufs returns +filedata from the pseudo-link instead of the lower readonly +branch. Because the pseudo-link is based upon the inode, to keep the +inode number by xino (see above) is essentially necessary. + +All the hardlinks under the Pseudo-link Directory of the writable branch +should be restored in a proper location later. Aufs provides a utility +to do this. The userspace helpers executed at remounting and unmounting +aufs by default. +During this utility is running, it puts aufs into the pseudo-link +maintenance mode. In this mode, only the process which began the +maintenance mode (and its child processes) is allowed to operate in +aufs. Some other processes which are not related to the pseudo-link will +be allowed to run too, but the rest have to return an error or wait +until the maintenance mode ends. If a process already acquires an inode +mutex (in VFS), it has to return an error. + + +XIB(external inode number bitmap) +---------------------------------------------------------------------- +Addition to the xino file per a branch, aufs has an external inode number +bitmap in a superblock object. It is also an internal file such like a +xino file. +It is a simple bitmap to mark whether the aufs inode number is in-use or +not. +To reduce the file I/O, aufs prepares a single memory page to cache xib. + +As well as XINO files, aufs has a feature to truncate/refresh XIB to +reduce the number of consumed disk blocks for these files. + + +Virtual or Vertical Dir, and Readdir in Userspace +---------------------------------------------------------------------- +In order to support multiple layers (branches), aufs readdir operation +constructs a virtual dir block on memory. For readdir, aufs calls +vfs_readdir() internally for each dir on branches, merges their entries +with eliminating the whiteout-ed ones, and sets it to file (dir) +object. So the file object has its entry list until it is closed. The +entry list will be updated when the file position is zero and becomes +obsoleted. This decision is made in aufs automatically. + +The dynamically allocated memory block for the name of entries has a +unit of 512 bytes (by default) and stores the names contiguously (no +padding). Another block for each entry is handled by kmem_cache too. +During building dir blocks, aufs creates hash list and judging whether +the entry is whiteouted by its upper branch or already listed. +The merged result is cached in the corresponding inode object and +maintained by a customizable life-time option. + +Some people may call it can be a security hole or invite DoS attack +since the opened and once readdir-ed dir (file object) holds its entry +list and becomes a pressure for system memory. But I'd say it is similar +to files under /proc or /sys. The virtual files in them also holds a +memory page (generally) while they are opened. When an idea to reduce +memory for them is introduced, it will be applied to aufs too. +For those who really hate this situation, I've developed readdir(3) +library which operates this merging in userspace. You just need to set +LD_PRELOAD environment variable, and aufs will not consume no memory in +kernel space for readdir(3). + + +Workqueue +---------------------------------------------------------------------- +Aufs sometimes requires privilege access to a branch. For instance, +in copy-up/down operation. When a user process is going to make changes +to a file which exists in the lower readonly branch only, and the mode +of one of ancestor directories may not be writable by a user +process. Here aufs copy-up the file with its ancestors and they may +require privilege to set its owner/group/mode/etc. +This is a typical case of a application character of aufs (see +Introduction). + +Aufs uses workqueue synchronously for this case. It creates its own +workqueue. The workqueue is a kernel thread and has privilege. Aufs +passes the request to call mkdir or write (for example), and wait for +its completion. This approach solves a problem of a signal handler +simply. +If aufs didn't adopt the workqueue and changed the privilege of the +process, then the process may receive the unexpected SIGXFSZ or other +signals. + +Also aufs uses the system global workqueue ("events" kernel thread) too +for asynchronous tasks, such like handling inotify/fsnotify, re-creating a +whiteout base and etc. This is unrelated to a privilege. +Most of aufs operation tries acquiring a rw_semaphore for aufs +superblock at the beginning, at the same time waits for the completion +of all queued asynchronous tasks. + + +Whiteout +---------------------------------------------------------------------- +The whiteout in aufs is very similar to Unionfs's. That is represented +by its filename. UnionMount takes an approach of a file mode, but I am +afraid several utilities (find(1) or something) will have to support it. + +Basically the whiteout represents "logical deletion" which stops aufs to +lookup further, but also it represents "dir is opaque" which also stop +further lookup. + +In aufs, rmdir(2) and rename(2) for dir uses whiteout alternatively. +In order to make several functions in a single systemcall to be +revertible, aufs adopts an approach to rename a directory to a temporary +unique whiteouted name. +For example, in rename(2) dir where the target dir already existed, aufs +renames the target dir to a temporary unique whiteouted name before the +actual rename on a branch, and then handles other actions (make it opaque, +update the attributes, etc). If an error happens in these actions, aufs +simply renames the whiteouted name back and returns an error. If all are +succeeded, aufs registers a function to remove the whiteouted unique +temporary name completely and asynchronously to the system global +workqueue. + + +Copy-up +---------------------------------------------------------------------- +It is a well-known feature or concept. +When user modifies a file on a readonly branch, aufs operate "copy-up" +internally and makes change to the new file on the upper writable branch. +When the trigger systemcall does not update the timestamps of the parent +dir, aufs reverts it after copy-up. + + +Move-down (aufs3.9 and later) +---------------------------------------------------------------------- +"Copy-up" is one of the essential feature in aufs. It copies a file from +the lower readonly branch to the upper writable branch when a user +changes something about the file. +"Move-down" is an opposite action of copy-up. Basically this action is +ran manually instead of automatically and internally. +For desgin and implementation, aufs has to consider these issues. +- whiteout for the file may exist on the lower branch. +- ancestor directories may not exist on the lower branch. +- diropq for the ancestor directories may exist on the upper branch. +- free space on the lower branch will reduce. +- another access to the file may happen during moving-down, including + UDBA (see "Revalidate Dentry and UDBA"). +- the file should not be hard-linked nor pseudo-linked. they should be + handled by auplink utility later. + +Sometimes users want to move-down a file from the upper writable branch +to the lower readonly or writable branch. For instance, +- the free space of the upper writable branch is going to run out. +- create a new intermediate branch between the upper and lower branch. +- etc. + +For this purpose, use "aumvdown" command in aufs-util.git. diff --git b/Documentation/filesystems/aufs/design/03atomic_open.txt b/Documentation/filesystems/aufs/design/03atomic_open.txt new file mode 100644 index 0000000..5f0aca4 --- /dev/null +++ b/Documentation/filesystems/aufs/design/03atomic_open.txt @@ -0,0 +1,85 @@ + +# Copyright (C) 2015-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Support for a branch who has its ->atomic_open() +---------------------------------------------------------------------- +The filesystems who implement its ->atomic_open() are not majority. For +example NFSv4 does, and aufs should call NFSv4 ->atomic_open, +particularly for open(O_CREAT|O_EXCL, 0400) case. Other than +->atomic_open(), NFSv4 returns an error for this open(2). While I am not +sure whether all filesystems who have ->atomic_open() behave like this, +but NFSv4 surely returns the error. + +In order to support ->atomic_open() for aufs, there are a few +approaches. + +A. Introduce aufs_atomic_open() + - calls one of VFS:do_last(), lookup_open() or atomic_open() for + branch fs. +B. Introduce aufs_atomic_open() calling create, open and chmod. this is + an aufs user Pip Cet's approach + - calls aufs_create(), VFS finish_open() and notify_change(). + - pass fake-mode to finish_open(), and then correct the mode by + notify_change(). +C. Extend aufs_open() to call branch fs's ->atomic_open() + - no aufs_atomic_open(). + - aufs_lookup() registers the TID to an aufs internal object. + - aufs_create() does nothing when the matching TID is registered, but + registers the mode. + - aufs_open() calls branch fs's ->atomic_open() when the matching + TID is registered. +D. Extend aufs_open() to re-try branch fs's ->open() with superuser's + credential + - no aufs_atomic_open(). + - aufs_create() registers the TID to an internal object. this info + represents "this process created this file just now." + - when aufs gets EACCES from branch fs's ->open(), then confirm the + registered TID and re-try open() with superuser's credential. + +Pros and cons for each approach. + +A. + - straightforward but highly depends upon VFS internal. + - the atomic behavaiour is kept. + - some of parameters such as nameidata are hard to reproduce for + branch fs. + - large overhead. +B. + - easy to implement. + - the atomic behavaiour is lost. +C. + - the atomic behavaiour is kept. + - dirty and tricky. + - VFS checks whether the file is created correctly after calling + ->create(), which means this approach doesn't work. +D. + - easy to implement. + - the atomic behavaiour is lost. + - to open a file with superuser's credential and give it to a user + process is a bad idea, since the file object keeps the credential + in it. It may affect LSM or something. This approach doesn't work + either. + +The approach A is ideal, but it hard to implement. So here is a +variation of A, which is to be implemented. + +A-1. Introduce aufs_atomic_open() + - calls branch fs ->atomic_open() if exists. otherwise calls + vfs_create() and finish_open(). + - the demerit is that the several checks after branch fs + ->atomic_open() are lost. in the ordinary case, the checks are + done by VFS:do_last(), lookup_open() and atomic_open(). some can + be implemented in aufs, but not all I am afraid. diff --git b/Documentation/filesystems/aufs/design/03lookup.txt b/Documentation/filesystems/aufs/design/03lookup.txt new file mode 100644 index 0000000..8b8ac6e --- /dev/null +++ b/Documentation/filesystems/aufs/design/03lookup.txt @@ -0,0 +1,113 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Lookup in a Branch +---------------------------------------------------------------------- +Since aufs has a character of sub-VFS (see Introduction), it operates +lookup for branches as VFS does. It may be a heavy work. But almost all +lookup operation in aufs is the simplest case, ie. lookup only an entry +directly connected to its parent. Digging down the directory hierarchy +is unnecessary. VFS has a function lookup_one_len() for that use, and +aufs calls it. + +When a branch is a remote filesystem, aufs basically relies upon its +->d_revalidate(), also aufs forces the hardest revalidate tests for +them. +For d_revalidate, aufs implements three levels of revalidate tests. See +"Revalidate Dentry and UDBA" in detail. + + +Test Only the Highest One for the Directory Permission (dirperm1 option) +---------------------------------------------------------------------- +Let's try case study. +- aufs has two branches, upper readwrite and lower readonly. + /au = /rw + /ro +- "dirA" exists under /ro, but /rw. and its mode is 0700. +- user invoked "chmod a+rx /au/dirA" +- the internal copy-up is activated and "/rw/dirA" is created and its + permission bits are set to world readable. +- then "/au/dirA" becomes world readable? + +In this case, /ro/dirA is still 0700 since it exists in readonly branch, +or it may be a natively readonly filesystem. If aufs respects the lower +branch, it should not respond readdir request from other users. But user +allowed it by chmod. Should really aufs rejects showing the entries +under /ro/dirA? + +To be honest, I don't have a good solution for this case. So aufs +implements 'dirperm1' and 'nodirperm1' mount options, and leave it to +users. +When dirperm1 is specified, aufs checks only the highest one for the +directory permission, and shows the entries. Otherwise, as usual, checks +every dir existing on all branches and rejects the request. + +As a side effect, dirperm1 option improves the performance of aufs +because the number of permission check is reduced when the number of +branch is many. + + +Revalidate Dentry and UDBA (User's Direct Branch Access) +---------------------------------------------------------------------- +Generally VFS helpers re-validate a dentry as a part of lookup. +0. digging down the directory hierarchy. +1. lock the parent dir by its i_mutex. +2. lookup the final (child) entry. +3. revalidate it. +4. call the actual operation (create, unlink, etc.) +5. unlock the parent dir + +If the filesystem implements its ->d_revalidate() (step 3), then it is +called. Actually aufs implements it and checks the dentry on a branch is +still valid. +But it is not enough. Because aufs has to release the lock for the +parent dir on a branch at the end of ->lookup() (step 2) and +->d_revalidate() (step 3) while the i_mutex of the aufs dir is still +held by VFS. +If the file on a branch is changed directly, eg. bypassing aufs, after +aufs released the lock, then the subsequent operation may cause +something unpleasant result. + +This situation is a result of VFS architecture, ->lookup() and +->d_revalidate() is separated. But I never say it is wrong. It is a good +design from VFS's point of view. It is just not suitable for sub-VFS +character in aufs. + +Aufs supports such case by three level of revalidation which is +selectable by user. +1. Simple Revalidate + Addition to the native flow in VFS's, confirm the child-parent + relationship on the branch just after locking the parent dir on the + branch in the "actual operation" (step 4). When this validation + fails, aufs returns EBUSY. ->d_revalidate() (step 3) in aufs still + checks the validation of the dentry on branches. +2. Monitor Changes Internally by Inotify/Fsnotify + Addition to above, in the "actual operation" (step 4) aufs re-lookup + the dentry on the branch, and returns EBUSY if it finds different + dentry. + Additionally, aufs sets the inotify/fsnotify watch for every dir on branches + during it is in cache. When the event is notified, aufs registers a + function to kernel 'events' thread by schedule_work(). And the + function sets some special status to the cached aufs dentry and inode + private data. If they are not cached, then aufs has nothing to + do. When the same file is accessed through aufs (step 0-3) later, + aufs will detect the status and refresh all necessary data. + In this mode, aufs has to ignore the event which is fired by aufs + itself. +3. No Extra Validation + This is the simplest test and doesn't add any additional revalidation + test, and skip the revalidation in step 4. It is useful and improves + aufs performance when system surely hide the aufs branches from user, + by over-mounting something (or another method). diff --git b/Documentation/filesystems/aufs/design/04branch.txt b/Documentation/filesystems/aufs/design/04branch.txt new file mode 100644 index 0000000..5604ff8 --- /dev/null +++ b/Documentation/filesystems/aufs/design/04branch.txt @@ -0,0 +1,74 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Branch Manipulation + +Since aufs supports dynamic branch manipulation, ie. add/remove a branch +and changing its permission/attribute, there are a lot of works to do. + + +Add a Branch +---------------------------------------------------------------------- +o Confirm the adding dir exists outside of aufs, including loopback + mount, and its various attributes. +o Initialize the xino file and whiteout bases if necessary. + See struct.txt. + +o Check the owner/group/mode of the directory + When the owner/group/mode of the adding directory differs from the + existing branch, aufs issues a warning because it may impose a + security risk. + For example, when a upper writable branch has a world writable empty + top directory, a malicious user can create any files on the writable + branch directly, like copy-up and modify manually. If something like + /etc/{passwd,shadow} exists on the lower readonly branch but the upper + writable branch, and the writable branch is world-writable, then a + malicious guy may create /etc/passwd on the writable branch directly + and the infected file will be valid in aufs. + I am afraid it can be a security issue, but aufs can do nothing except + producing a warning. + + +Delete a Branch +---------------------------------------------------------------------- +o Confirm the deleting branch is not busy + To be general, there is one merit to adopt "remount" interface to + manipulate branches. It is to discard caches. At deleting a branch, + aufs checks the still cached (and connected) dentries and inodes. If + there are any, then they are all in-use. An inode without its + corresponding dentry can be alive alone (for example, inotify/fsnotify case). + + For the cached one, aufs checks whether the same named entry exists on + other branches. + If the cached one is a directory, because aufs provides a merged view + to users, as long as one dir is left on any branch aufs can show the + dir to users. In this case, the branch can be removed from aufs. + Otherwise aufs rejects deleting the branch. + + If any file on the deleting branch is opened by aufs, then aufs + rejects deleting. + + +Modify the Permission of a Branch +---------------------------------------------------------------------- +o Re-initialize or remove the xino file and whiteout bases if necessary. + See struct.txt. + +o rw --> ro: Confirm the modifying branch is not busy + Aufs rejects the request if any of these conditions are true. + - a file on the branch is mmap-ed. + - a regular file on the branch is opened for write and there is no + same named entry on the upper branch. diff --git b/Documentation/filesystems/aufs/design/05wbr_policy.txt b/Documentation/filesystems/aufs/design/05wbr_policy.txt new file mode 100644 index 0000000..1578469 --- /dev/null +++ b/Documentation/filesystems/aufs/design/05wbr_policy.txt @@ -0,0 +1,64 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Policies to Select One among Multiple Writable Branches +---------------------------------------------------------------------- +When the number of writable branch is more than one, aufs has to decide +the target branch for file creation or copy-up. By default, the highest +writable branch which has the parent (or ancestor) dir of the target +file is chosen (top-down-parent policy). +By user's request, aufs implements some other policies to select the +writable branch, for file creation several policies, round-robin, +most-free-space, and other policies. For copy-up, top-down-parent, +bottom-up-parent, bottom-up and others. + +As expected, the round-robin policy selects the branch in circular. When +you have two writable branches and creates 10 new files, 5 files will be +created for each branch. mkdir(2) systemcall is an exception. When you +create 10 new directories, all will be created on the same branch. +And the most-free-space policy selects the one which has most free +space among the writable branches. The amount of free space will be +checked by aufs internally, and users can specify its time interval. + +The policies for copy-up is more simple, +top-down-parent is equivalent to the same named on in create policy, +bottom-up-parent selects the writable branch where the parent dir +exists and the nearest upper one from the copyup-source, +bottom-up selects the nearest upper writable branch from the +copyup-source, regardless the existence of the parent dir. + +There are some rules or exceptions to apply these policies. +- If there is a readonly branch above the policy-selected branch and + the parent dir is marked as opaque (a variation of whiteout), or the + target (creating) file is whiteout-ed on the upper readonly branch, + then the result of the policy is ignored and the target file will be + created on the nearest upper writable branch than the readonly branch. +- If there is a writable branch above the policy-selected branch and + the parent dir is marked as opaque or the target file is whiteouted + on the branch, then the result of the policy is ignored and the target + file will be created on the highest one among the upper writable + branches who has diropq or whiteout. In case of whiteout, aufs removes + it as usual. +- link(2) and rename(2) systemcalls are exceptions in every policy. + They try selecting the branch where the source exists as possible + since copyup a large file will take long time. If it can't be, + ie. the branch where the source exists is readonly, then they will + follow the copyup policy. +- There is an exception for rename(2) when the target exists. + If the rename target exists, aufs compares the index of the branches + where the source and the target exists and selects the higher + one. If the selected branch is readonly, then aufs follows the + copyup policy. diff --git b/Documentation/filesystems/aufs/design/06dirren.dot b/Documentation/filesystems/aufs/design/06dirren.dot new file mode 100644 index 0000000..2d62bb6 --- /dev/null +++ b/Documentation/filesystems/aufs/design/06dirren.dot @@ -0,0 +1,31 @@ + +// to view this graph, run dot(1) command in GRAPHVIZ. + +digraph G { +node [shape=box]; +whinfo [label="detailed info file\n(lower_brid_root-hinum, h_inum, namelen, old name)"]; + +node [shape=oval]; + +aufs_rename -> whinfo [label="store/remove"]; + +node [shape=oval]; +inode_list [label="h_inum list in branch\ncache"]; + +node [shape=box]; +whinode [label="h_inum list file"]; + +node [shape=oval]; +brmgmt [label="br_add/del/mod/umount"]; + +brmgmt -> inode_list [label="create/remove"]; +brmgmt -> whinode [label="load/store"]; + +inode_list -> whinode [style=dashed,dir=both]; + +aufs_rename -> inode_list [label="add/del"]; + +aufs_lookup -> inode_list [label="search"]; + +aufs_lookup -> whinfo [label="load/remove"]; +} diff --git b/Documentation/filesystems/aufs/design/06dirren.txt b/Documentation/filesystems/aufs/design/06dirren.txt new file mode 100644 index 0000000..3037d77 --- /dev/null +++ b/Documentation/filesystems/aufs/design/06dirren.txt @@ -0,0 +1,102 @@ + +# Copyright (C) 2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Special handling for renaming a directory (DIRREN) +---------------------------------------------------------------------- +First, let's assume we have a simple usecase. + +- /u = /rw + /ro +- /rw/dirA exists +- /ro/dirA and /ro/dirA/file exist too +- there is no dirB on both branches +- a user issues rename("dirA", "dirB") + +Now, what should aufs behave against this rename(2)? +There are a few possible cases. + +A. returns EROFS. + since dirA exists on a readonly branch which cannot be renamed. +B. returns EXDEV. + it is possible to copy-up dirA (only the dir itself), but the child + entries ("file" in this case) should not be. it must be a bad + approach to copy-up recursively. +C. returns a success. + even the branch /ro is readonly, aufs tries renaming it. Obviously it + is a violation of aufs' policy. +D. construct an extra information which indicates that /ro/dirA should + be handled as the name of dirB. + overlayfs has a similar feature called REDIRECT. + +Until now, aufs implements the case B only which returns EXDEV, and +expects the userspace application behaves like mv(1) which tries +issueing rename(2) recursively. + +A new aufs feature called DIRREN is introduced which implements the case +D. There are several "extra information" added. + +1. detailed info per renamed directory + path: /rw/dirB/$AUFS_WH_DR_INFO_PFX. +2. the inode-number list of directories on a branch + path: /rw/dirB/$AUFS_WH_DR_BRHINO + +The filename of "detailed info per directory" represents the lower +branch, and its format is +- a type of the branch id + one of these. + + uuid (not implemented yet) + + fsid + + dev +- the inode-number of the branch root dir + +And it contains these info in a single regular file. +- magic number +- branch's inode-number of the logically renamed dir +- the name of the before-renamed dir + +The "detailed info per directory" file is created in aufs rename(2), and +loaded in any lookup. +The info is considered in lookup for the matching case only. Here +"matching" means that the root of branch (in the info filename) is same +to the current looking-up branch. After looking-up the before-renamed +name, the inode-number is compared. And the matched dentry is used. + +The "inode-number list of directories" is a regular file which contains +simply the inode-numbers on the branch. The file is created or updated +in removing the branch, and loaded in adding the branch. Its lifetime is +equal to the branch. +The list is refered in lookup, and when the current target inode is +found in the list, the aufs tries loading the "detailed info per +directory" and get the changed and valid name of the dir. + +Theoretically these "extra informaiton" may be able to be put into XATTR +in the dir inode. But aufs doesn't choose this way because +1. XATTR may not be supported by the branch (or its configuration) +2. XATTR may have its size limit. +3. XATTR may be less easy to convert than a regular file, when the + format of the info is changed in the future. +At the same time, I agree that the regular file approach is much slower +than XATTR approach. So, in the future, aufs may take the XATTR or other +better approach. + +This DIRREN feature is enabled by aufs configuration, and is activated +by a new mount option. + +For the more complicated case, there is a work with UDBA option, which +is to dected the direct access to the branches (by-passing aufs) and to +maintain the cashes in aufs. Since a single cached aufs dentry may +contains two names, before- and after-rename, the name comparision in +UDBA handler may not work correctly. In this case, the behaviour will be +equivalen to udba=reval case. diff --git b/Documentation/filesystems/aufs/design/06fhsm.txt b/Documentation/filesystems/aufs/design/06fhsm.txt new file mode 100644 index 0000000..9216478 --- /dev/null +++ b/Documentation/filesystems/aufs/design/06fhsm.txt @@ -0,0 +1,120 @@ + +# Copyright (C) 2011-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + +File-based Hierarchical Storage Management (FHSM) +---------------------------------------------------------------------- +Hierarchical Storage Management (or HSM) is a well-known feature in the +storage world. Aufs provides this feature as file-based with multiple +writable branches, based upon the principle of "Colder, the Lower". +Here the word "colder" means that the less used files, and "lower" means +that the position in the order of the stacked branches vertically. +These multiple writable branches are prioritized, ie. the topmost one +should be the fastest drive and be used heavily. + +o Characters in aufs FHSM story +- aufs itself and a new branch attribute. +- a new ioctl interface to move-down and to establish a connection with + the daemon ("move-down" is a converse of "copy-up"). +- userspace tool and daemon. + +The userspace daemon establishes a connection with aufs and waits for +the notification. The notified information is very similar to struct +statfs containing the number of consumed blocks and inodes. +When the consumed blocks/inodes of a branch exceeds the user-specified +upper watermark, the daemon activates its move-down process until the +consumed blocks/inodes reaches the user-specified lower watermark. + +The actual move-down is done by aufs based upon the request from +user-space since we need to maintain the inode number and the internal +pointer arrays in aufs. + +Currently aufs FHSM handles the regular files only. Additionally they +must not be hard-linked nor pseudo-linked. + + +o Cowork of aufs and the user-space daemon + During the userspace daemon established the connection, aufs sends a + small notification to it whenever aufs writes something into the + writable branch. But it may cost high since aufs issues statfs(2) + internally. So user can specify a new option to cache the + info. Actually the notification is controlled by these factors. + + the specified cache time. + + classified as "force" by aufs internally. + Until the specified time expires, aufs doesn't send the info + except the forced cases. When aufs decide forcing, the info is always + notified to userspace. + For example, the number of free inodes is generally large enough and + the shortage of it happens rarely. So aufs doesn't force the + notification when creating a new file, directory and others. This is + the typical case which aufs doesn't force. + When aufs writes the actual filedata and the files consumes any of new + blocks, the aufs forces notifying. + + +o Interfaces in aufs +- New branch attribute. + + fhsm + Specifies that the branch is managed by FHSM feature. In other word, + participant in the FHSM. + When nofhsm is set to the branch, it will not be the source/target + branch of the move-down operation. This attribute is set + independently from coo and moo attributes, and if you want full + FHSM, you should specify them as well. +- New mount option. + + fhsm_sec + Specifies a second to suppress many less important info to be + notified. +- New ioctl. + + AUFS_CTL_FHSM_FD + create a new file descriptor which userspace can read the notification + (a subset of struct statfs) from aufs. +- Module parameter 'brs' + It has to be set to 1. Otherwise the new mount option 'fhsm' will not + be set. +- mount helpers /sbin/mount.aufs and /sbin/umount.aufs + When there are two or more branches with fhsm attributes, + /sbin/mount.aufs invokes the user-space daemon and /sbin/umount.aufs + terminates it. As a result of remounting and branch-manipulation, the + number of branches with fhsm attribute can be one. In this case, + /sbin/mount.aufs will terminate the user-space daemon. + + +Finally the operation is done as these steps in kernel-space. +- make sure that, + + no one else is using the file. + + the file is not hard-linked. + + the file is not pseudo-linked. + + the file is a regular file. + + the parent dir is not opaqued. +- find the target writable branch. +- make sure the file is not whiteout-ed by the upper (than the target) + branch. +- make the parent dir on the target branch. +- mutex lock the inode on the branch. +- unlink the whiteout on the target branch (if exists). +- lookup and create the whiteout-ed temporary name on the target branch. +- copy the file as the whiteout-ed temporary name on the target branch. +- rename the whiteout-ed temporary name to the original name. +- unlink the file on the source branch. +- maintain the internal pointer array and the external inode number + table (XINO). +- maintain the timestamps and other attributes of the parent dir and the + file. + +And of course, in every step, an error may happen. So the operation +should restore the original file state after an error happens. diff --git b/Documentation/filesystems/aufs/design/06mmap.txt b/Documentation/filesystems/aufs/design/06mmap.txt new file mode 100644 index 0000000..8fe4b6c --- /dev/null +++ b/Documentation/filesystems/aufs/design/06mmap.txt @@ -0,0 +1,72 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +mmap(2) -- File Memory Mapping +---------------------------------------------------------------------- +In aufs, the file-mapped pages are handled by a branch fs directly, no +interaction with aufs. It means aufs_mmap() calls the branch fs's +->mmap(). +This approach is simple and good, but there is one problem. +Under /proc, several entries show the mmapped files by its path (with +device and inode number), and the printed path will be the path on the +branch fs's instead of virtual aufs's. +This is not a problem in most cases, but some utilities lsof(1) (and its +user) may expect the path on aufs. + +To address this issue, aufs adds a new member called vm_prfile in struct +vm_area_struct (and struct vm_region). The original vm_file points to +the file on the branch fs in order to handle everything correctly as +usual. The new vm_prfile points to a virtual file in aufs, and the +show-functions in procfs refers to vm_prfile if it is set. +Also we need to maintain several other places where touching vm_file +such like +- fork()/clone() copies vma and the reference count of vm_file is + incremented. +- merging vma maintains the ref count too. + +This is not a good approach. It just fakes the printed path. But it +leaves all behaviour around f_mapping unchanged. This is surely an +advantage. +Actually aufs had adopted another complicated approach which calls +generic_file_mmap() and handles struct vm_operations_struct. In this +approach, aufs met a hard problem and I could not solve it without +switching the approach. + +There may be one more another approach which is +- bind-mount the branch-root onto the aufs-root internally +- grab the new vfsmount (ie. struct mount) +- lazy-umount the branch-root internally +- in open(2) the aufs-file, open the branch-file with the hidden + vfsmount (instead of the original branch's vfsmount) +- ideally this "bind-mount and lazy-umount" should be done atomically, + but it may be possible from userspace by the mount helper. + +Adding the internal hidden vfsmount and using it in opening a file, the +file path under /proc will be printed correctly. This approach looks +smarter, but is not possible I am afraid. +- aufs-root may be bind-mount later. when it happens, another hidden + vfsmount will be required. +- it is hard to get the chance to bind-mount and lazy-umount + + in kernel-space, FS can have vfsmount in open(2) via + file->f_path, and aufs can know its vfsmount. But several locks are + already acquired, and if aufs tries to bind-mount and lazy-umount + here, then it may cause a deadlock. + + in user-space, bind-mount doesn't invoke the mount helper. +- since /proc shows dev and ino, aufs has to give vma these info. it + means a new member vm_prinode will be necessary. this is essentially + equivalent to vm_prfile described above. + +I have to give up this "looks-smater" approach. diff --git b/Documentation/filesystems/aufs/design/06xattr.txt b/Documentation/filesystems/aufs/design/06xattr.txt new file mode 100644 index 0000000..37cdb4e --- /dev/null +++ b/Documentation/filesystems/aufs/design/06xattr.txt @@ -0,0 +1,96 @@ + +# Copyright (C) 2014-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + +Listing XATTR/EA and getting the value +---------------------------------------------------------------------- +For the inode standard attributes (owner, group, timestamps, etc.), aufs +shows the values from the topmost existing file. This behaviour is good +for the non-dir entries since the bahaviour exactly matches the shown +information. But for the directories, aufs considers all the same named +entries on the lower branches. Which means, if one of the lower entry +rejects readdir call, then aufs returns an error even if the topmost +entry allows it. This behaviour is necessary to respect the branch fs's +security, but can make users confused since the user-visible standard +attributes don't match the behaviour. +To address this issue, aufs has a mount option called dirperm1 which +checks the permission for the topmost entry only, and ignores the lower +entry's permission. + +A similar issue can happen around XATTR. +getxattr(2) and listxattr(2) families behave as if dirperm1 option is +always set. Otherwise these very unpleasant situation would happen. +- listxattr(2) may return the duplicated entries. +- users may not be able to remove or reset the XATTR forever, + + +XATTR/EA support in the internal (copy,move)-(up,down) +---------------------------------------------------------------------- +Generally the extended attributes of inode are categorized as these. +- "security" for LSM and capability. +- "system" for posix ACL, 'acl' mount option is required for the branch + fs generally. +- "trusted" for userspace, CAP_SYS_ADMIN is required. +- "user" for userspace, 'user_xattr' mount option is required for the + branch fs generally. + +Moreover there are some other categories. Aufs handles these rather +unpopular categories as the ordinary ones, ie. there is no special +condition nor exception. + +In copy-up, the support for XATTR on the dst branch may differ from the +src branch. In this case, the copy-up operation will get an error and +the original user operation which triggered the copy-up will fail. It +can happen that even all copy-up will fail. +When both of src and dst branches support XATTR and if an error occurs +during copying XATTR, then the copy-up should fail obviously. That is a +good reason and aufs should return an error to userspace. But when only +the src branch support that XATTR, aufs should not return an error. +For example, the src branch supports ACL but the dst branch doesn't +because the dst branch may natively un-support it or temporary +un-support it due to "noacl" mount option. Of course, the dst branch fs +may NOT return an error even if the XATTR is not supported. It is +totally up to the branch fs. + +Anyway when the aufs internal copy-up gets an error from the dst branch +fs, then aufs tries removing the just copied entry and returns the error +to the userspace. The worst case of this situation will be all copy-up +will fail. + +For the copy-up operation, there two basic approaches. +- copy the specified XATTR only (by category above), and return the + error unconditionally if it happens. +- copy all XATTR, and ignore the error on the specified category only. + +In order to support XATTR and to implement the correct behaviour, aufs +chooses the latter approach and introduces some new branch attributes, +"icexsec", "icexsys", "icextr", "icexusr", and "icexoth". +They correspond to the XATTR namespaces (see above). Additionally, to be +convenient, "icex" is also provided which means all "icex*" attributes +are set (here the word "icex" stands for "ignore copy-error on XATTR"). + +The meaning of these attributes is to ignore the error from setting +XATTR on that branch. +Note that aufs tries copying all XATTR unconditionally, and ignores the +error from the dst branch according to the specified attributes. + +Some XATTR may have its default value. The default value may come from +the parent dir or the environment. If the default value is set at the +file creating-time, it will be overwritten by copy-up. +Some contradiction may happen I am afraid. +Do we need another attribute to stop copying XATTR? I am unsure. For +now, aufs implements the branch attributes to ignore the error. diff --git b/Documentation/filesystems/aufs/design/07export.txt b/Documentation/filesystems/aufs/design/07export.txt new file mode 100644 index 0000000..cd4ee6b --- /dev/null +++ b/Documentation/filesystems/aufs/design/07export.txt @@ -0,0 +1,58 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Export Aufs via NFS +---------------------------------------------------------------------- +Here is an approach. +- like xino/xib, add a new file 'xigen' which stores aufs inode + generation. +- iget_locked(): initialize aufs inode generation for a new inode, and + store it in xigen file. +- destroy_inode(): increment aufs inode generation and store it in xigen + file. it is necessary even if it is not unlinked, because any data of + inode may be changed by UDBA. +- encode_fh(): for a root dir, simply return FILEID_ROOT. otherwise + build file handle by + + branch id (4 bytes) + + superblock generation (4 bytes) + + inode number (4 or 8 bytes) + + parent dir inode number (4 or 8 bytes) + + inode generation (4 bytes)) + + return value of exportfs_encode_fh() for the parent on a branch (4 + bytes) + + file handle for a branch (by exportfs_encode_fh()) +- fh_to_dentry(): + + find the index of a branch from its id in handle, and check it is + still exist in aufs. + + 1st level: get the inode number from handle and search it in cache. + + 2nd level: if not found in cache, get the parent inode number from + the handle and search it in cache. and then open the found parent + dir, find the matching inode number by vfs_readdir() and get its + name, and call lookup_one_len() for the target dentry. + + 3rd level: if the parent dir is not cached, call + exportfs_decode_fh() for a branch and get the parent on a branch, + build a pathname of it, convert it a pathname in aufs, call + path_lookup(). now aufs gets a parent dir dentry, then handle it as + the 2nd level. + + to open the dir, aufs needs struct vfsmount. aufs keeps vfsmount + for every branch, but not itself. to get this, (currently) aufs + searches in current->nsproxy->mnt_ns list. it may not be a good + idea, but I didn't get other approach. + + test the generation of the gotten inode. +- every inode operation: they may get EBUSY due to UDBA. in this case, + convert it into ESTALE for NFSD. +- readdir(): call lockdep_on/off() because filldir in NFSD calls + lookup_one_len(), vfs_getattr(), encode_fh() and others. diff --git b/Documentation/filesystems/aufs/design/08shwh.txt b/Documentation/filesystems/aufs/design/08shwh.txt new file mode 100644 index 0000000..7e07e26 --- /dev/null +++ b/Documentation/filesystems/aufs/design/08shwh.txt @@ -0,0 +1,52 @@ + +# Copyright (C) 2005-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Show Whiteout Mode (shwh) +---------------------------------------------------------------------- +Generally aufs hides the name of whiteouts. But in some cases, to show +them is very useful for users. For instance, creating a new middle layer +(branch) by merging existing layers. + +(borrowing aufs1 HOW-TO from a user, Michael Towers) +When you have three branches, +- Bottom: 'system', squashfs (underlying base system), read-only +- Middle: 'mods', squashfs, read-only +- Top: 'overlay', ram (tmpfs), read-write + +The top layer is loaded at boot time and saved at shutdown, to preserve +the changes made to the system during the session. +When larger changes have been made, or smaller changes have accumulated, +the size of the saved top layer data grows. At this point, it would be +nice to be able to merge the two overlay branches ('mods' and 'overlay') +and rewrite the 'mods' squashfs, clearing the top layer and thus +restoring save and load speed. + +This merging is simplified by the use of another aufs mount, of just the +two overlay branches using the 'shwh' option. +# mount -t aufs -o ro,shwh,br:/livesys/overlay=ro+wh:/livesys/mods=rr+wh \ + aufs /livesys/merge_union + +A merged view of these two branches is then available at +/livesys/merge_union, and the new feature is that the whiteouts are +visible! +Note that in 'shwh' mode the aufs mount must be 'ro', which will disable +writing to all branches. Also the default mode for all branches is 'ro'. +It is now possible to save the combined contents of the two overlay +branches to a new squashfs, e.g.: +# mksquashfs /livesys/merge_union /path/to/newmods.squash + +This new squashfs archive can be stored on the boot device and the +initramfs will use it to replace the old one at the next boot. diff --git b/Documentation/filesystems/aufs/design/10dynop.txt b/Documentation/filesystems/aufs/design/10dynop.txt new file mode 100644 index 0000000..b7ba75d --- /dev/null +++ b/Documentation/filesystems/aufs/design/10dynop.txt @@ -0,0 +1,47 @@ + +# Copyright (C) 2010-2017 Junjiro R. Okajima +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +Dynamically customizable FS operations +---------------------------------------------------------------------- +Generally FS operations (struct inode_operations, struct +address_space_operations, struct file_operations, etc.) are defined as +"static const", but it never means that FS have only one set of +operation. Some FS have multiple sets of them. For instance, ext2 has +three sets, one for XIP, for NOBH, and for normal. +Since aufs overrides and redirects these operations, sometimes aufs has +to change its behaviour according to the branch FS type. More importantly +VFS acts differently if a function (member in the struct) is set or +not. It means aufs should have several sets of operations and select one +among them according to the branch FS definition. + +In order to solve this problem and not to affect the behaviour of VFS, +aufs defines these operations dynamically. For instance, aufs defines +dummy direct_IO function for struct address_space_operations, but it may +not be set to the address_space_operations actually. When the branch FS +doesn't have it, aufs doesn't set it to its address_space_operations +while the function definition itself is still alive. So the behaviour +itself will not change, and it will return an error when direct_IO is +not set. + +The lifetime of these dynamically generated operation object is +maintained by aufs branch object. When the branch is removed from aufs, +the reference counter of the object is decremented. When it reaches +zero, the dynamically generated operation object will be freed. + +This approach is designed to support AIO (io_submit), Direct I/O and +XIP (DAX) mainly. +Currently this approach is applied to address_space_operations for +regular files only. diff --git b/Documentation/power/tuxonice-internals.txt b/Documentation/power/tuxonice-internals.txt new file mode 100644 index 0000000..0c6a216 --- /dev/null +++ b/Documentation/power/tuxonice-internals.txt @@ -0,0 +1,532 @@ + TuxOnIce 4.0 Internal Documentation. + Updated to 23 March 2015 + +(Please note that incremental image support mentioned in this document is work +in progress. This document may need updating prior to the actual release of +4.0!) + +1. Introduction. + + TuxOnIce 4.0 is an addition to the Linux Kernel, designed to + allow the user to quickly shutdown and quickly boot a computer, without + needing to close documents or programs. It is equivalent to the + hibernate facility in some laptops. This implementation, however, + requires no special BIOS or hardware support. + + The code in these files is based upon the original implementation + prepared by Gabor Kuti and additional work by Pavel Machek and a + host of others. This code has been substantially reworked by Nigel + Cunningham, again with the help and testing of many others, not the + least of whom are Bernard Blackham and Michael Frank. At its heart, + however, the operation is essentially the same as Gabor's version. + +2. Overview of operation. + + The basic sequence of operations is as follows: + + a. Quiesce all other activity. + b. Ensure enough memory and storage space are available, and attempt + to free memory/storage if necessary. + c. Allocate the required memory and storage space. + d. Write the image. + e. Power down. + + There are a number of complicating factors which mean that things are + not as simple as the above would imply, however... + + o The activity of each process must be stopped at a point where it will + not be holding locks necessary for saving the image, or unexpectedly + restart operations due to something like a timeout and thereby make + our image inconsistent. + + o It is desirous that we sync outstanding I/O to disk before calculating + image statistics. This reduces corruption if one should suspend but + then not resume, and also makes later parts of the operation safer (see + below). + + o We need to get as close as we can to an atomic copy of the data. + Inconsistencies in the image will result in inconsistent memory contents at + resume time, and thus in instability of the system and/or file system + corruption. This would appear to imply a maximum image size of one half of + the amount of RAM, but we have a solution... (again, below). + + o In 2.6 and later, we choose to play nicely with the other suspend-to-disk + implementations. + +3. Detailed description of internals. + + a. Quiescing activity. + + Safely quiescing the system is achieved using three separate but related + aspects. + + First, we use the vanilla kerne's support for freezing processes. This code + is based on the observation that the vast majority of processes don't need + to run during suspend. They can be 'frozen'. The kernel therefore + implements a refrigerator routine, which processes enter and in which they + remain until the cycle is complete. Processes enter the refrigerator via + try_to_freeze() invocations at appropriate places. A process cannot be + frozen in any old place. It must not be holding locks that will be needed + for writing the image or freezing other processes. For this reason, + userspace processes generally enter the refrigerator via the signal + handling code, and kernel threads at the place in their event loops where + they drop locks and yield to other processes or sleep. The task of freezing + processes is complicated by the fact that there can be interdependencies + between processes. Freezing process A before process B may mean that + process B cannot be frozen, because it stops at waiting for process A + rather than in the refrigerator. This issue is seen where userspace waits + on freezeable kernel threads or fuse filesystem threads. To address this + issue, we implement the following algorithm for quiescing activity: + + - Freeze filesystems (including fuse - userspace programs starting + new requests are immediately frozen; programs already running + requests complete their work before being frozen in the next + step) + - Freeze userspace + - Thaw filesystems (this is safe now that userspace is frozen and no + fuse requests are outstanding). + - Invoke sys_sync (noop on fuse). + - Freeze filesystems + - Freeze kernel threads + + If we need to free memory, we thaw kernel threads and filesystems, but not + userspace. We can then free caches without worrying about deadlocks due to + swap files being on frozen filesystems or such like. + + b. Ensure enough memory & storage are available. + + We have a number of constraints to meet in order to be able to successfully + suspend and resume. + + First, the image will be written in two parts, described below. One of + these parts needs to have an atomic copy made, which of course implies a + maximum size of one half of the amount of system memory. The other part + ('pageset') is not atomically copied, and can therefore be as large or + small as desired. + + Second, we have constraints on the amount of storage available. In these + calculations, we may also consider any compression that will be done. The + cryptoapi module allows the user to configure an expected compression ratio. + + Third, the user can specify an arbitrary limit on the image size, in + megabytes. This limit is treated as a soft limit, so that we don't fail the + attempt to suspend if we cannot meet this constraint. + + c. Allocate the required memory and storage space. + + Having done the initial freeze, we determine whether the above constraints + are met, and seek to allocate the metadata for the image. If the constraints + are not met, or we fail to allocate the required space for the metadata, we + seek to free the amount of memory that we calculate is needed and try again. + We allow up to four iterations of this loop before aborting the cycle. If + we do fail, it should only be because of a bug in TuxOnIce's calculations + or the vanilla kernel code for freeing memory. + + These steps are merged together in the prepare_image function, found in + prepare_image.c. The functions are merged because of the cyclical nature + of the problem of calculating how much memory and storage is needed. Since + the data structures containing the information about the image must + themselves take memory and use storage, the amount of memory and storage + required changes as we prepare the image. Since the changes are not large, + only one or two iterations will be required to achieve a solution. + + The recursive nature of the algorithm is miminised by keeping user space + frozen while preparing the image, and by the fact that our records of which + pages are to be saved and which pageset they are saved in use bitmaps (so + that changes in number or fragmentation of the pages to be saved don't + feedback via changes in the amount of memory needed for metadata). The + recursiveness is thus limited to any extra slab pages allocated to store the + extents that record storage used, and the effects of seeking to free memory. + + d. Write the image. + + We previously mentioned the need to create an atomic copy of the data, and + the half-of-memory limitation that is implied in this. This limitation is + circumvented by dividing the memory to be saved into two parts, called + pagesets. + + Pageset2 contains most of the page cache - the pages on the active and + inactive LRU lists that aren't needed or modified while TuxOnIce is + running, so they can be safely written without an atomic copy. They are + therefore saved first and reloaded last. While saving these pages, + TuxOnIce carefully ensures that the work of writing the pages doesn't make + the image inconsistent. With the support for Kernel (Video) Mode Setting + going into the kernel at the time of writing, we need to check for pages + on the LRU that are used by KMS, and exclude them from pageset2. They are + atomically copied as part of pageset 1. + + Once pageset2 has been saved, we prepare to do the atomic copy of remaining + memory. As part of the preparation, we power down drivers, thereby providing + them with the opportunity to have their state recorded in the image. The + amount of memory allocated by drivers for this is usually negligible, but if + DRI is in use, video drivers may require significants amounts. Ideally we + would be able to query drivers while preparing the image as to the amount of + memory they will need. Unfortunately no such mechanism exists at the time of + writing. For this reason, TuxOnIce allows the user to set an + 'extra_pages_allowance', which is used to seek to ensure sufficient memory + is available for drivers at this point. TuxOnIce also lets the user set this + value to 0. In this case, a test driver suspend is done while preparing the + image, and the difference (plus a margin) used instead. TuxOnIce will also + automatically restart the hibernation process (twice at most) if it finds + that the extra pages allowance is not sufficient. It will then use what was + actually needed (plus a margin, again). Failure to hibernate should thus + be an extremely rare occurence. + + Having suspended the drivers, we save the CPU context before making an + atomic copy of pageset1, resuming the drivers and saving the atomic copy. + After saving the two pagesets, we just need to save our metadata before + powering down. + + As we mentioned earlier, the contents of pageset2 pages aren't needed once + they've been saved. We therefore use them as the destination of our atomic + copy. In the unlikely event that pageset1 is larger, extra pages are + allocated while the image is being prepared. This is normally only a real + possibility when the system has just been booted and the page cache is + small. + + This is where we need to be careful about syncing, however. Pageset2 will + probably contain filesystem meta data. If this is overwritten with pageset1 + and then a sync occurs, the filesystem will be corrupted - at least until + resume time and another sync of the restored data. Since there is a + possibility that the user might not resume or (may it never be!) that + TuxOnIce might oops, we do our utmost to avoid syncing filesystems after + copying pageset1. + + e. Incremental images + + TuxOnIce 4.0 introduces a new incremental image mode which changes things a + little. When incremental images are enabled, we save a 'normal' image the + first time we hibernate. One resume however, we do not free the image or + the associated storage. Instead, it is retained until the next attempt at + hibernating and a mechanism is enabled which is used to track which pages + of memory are modified between the two cycles. The modified pages can then + be added to the existing image, rather than unmodified pages being saved + again unnecessarily. + + Incremental image support is available in 64 bit Linux only, due to the + requirement for extra page flags. + + This support is accomplished in the following way: + + 1) Tracking of pages. + + The tracking of changed pages is accomplished using the page fault + mechanism. When we reach a point at which we want to start tracking + changes, most pages are marked read-only and also flagged as being + read-only because of this support. Since this cannot happen for every page + of RAM, some are marked as untracked and always treated as modified whn + preparing an incremental iamge. When a process attempts to modify a page + that is marked read-only in this way, a page fault occurs, with TuxOnIce + code marking the page writable and dirty before allowing the write to + continue. In this way, the effect of incremental images on performance is + minimised - a page only causes a fault once. Small modifications to the + page allocator further reduce the number of faults that occur - free pages + are not tracked; they are made writable and marked as dirty as part of + being allocated. + + 2) Saving the incremental image / atomicity. + + The page fault mechanism is also used to improve the means by which + atomicity of the image is acheived. When it is time to do an atomic copy, + the flags for pages are reset, with the result being that it is no longer + necessary for us to do an atomic of pageset1. Instead, we normally write + the uncopied pages to disk. When an attempt is made to modify a page that + has not yet been saved, the page-fault mechanism makes a copy of the page + prior to allowing the write. This copy is then written to disk. Likewise, + on resume, if a process attempts to write to a page that has been read + while the rest of the image is still being loaded, a copy of that page is + made prior to the write being allowed. At the end of loading the image, + modified pages can thus be restored to their 'atomic copy' contents prior + to restarting normal operation. We also mark pages that are yet to be read + as invalid PFNs, so that we can capture as a bug any attempt by a + half-restored kernel to access a page that hasn't yet been reloaded. + + f. Power down. + + Powering down uses standard kernel routines. TuxOnIce supports powering down + using the ACPI S3, S4 and S5 methods or the kernel's non-ACPI power-off. + Supporting suspend to ram (S3) as a power off option might sound strange, + but it allows the user to quickly get their system up and running again if + the battery doesn't run out (we just need to re-read the overwritten pages) + and if the battery does run out (or the user removes power), they can still + resume. + +4. Data Structures. + + TuxOnIce uses three main structures to store its metadata and configuration + information: + + a) Pageflags bitmaps. + + TuxOnIce records which pages will be in pageset1, pageset2, the destination + of the atomic copy and the source of the atomically restored image using + bitmaps. The code used is that written for swsusp, with small improvements + to match TuxOnIce's requirements. + + The pageset1 bitmap is thus easily stored in the image header for use at + resume time. + + As mentioned above, using bitmaps also means that the amount of memory and + storage required for recording the above information is constant. This + greatly simplifies the work of preparing the image. In earlier versions of + TuxOnIce, extents were used to record which pages would be stored. In that + case, however, eating memory could result in greater fragmentation of the + lists of pages, which in turn required more memory to store the extents and + more storage in the image header. These could in turn require further + freeing of memory, and another iteration. All of this complexity is removed + by having bitmaps. + + Bitmaps also make a lot of sense because TuxOnIce only ever iterates + through the lists. There is therefore no cost to not being able to find the + nth page in order 0 time. We only need to worry about the cost of finding + the n+1th page, given the location of the nth page. Bitwise optimisations + help here. + + b) Extents for block data. + + TuxOnIce supports writing the image to multiple block devices. In the case + of swap, multiple partitions and/or files may be in use, and we happily use + them all (with the exception of compcache pages, which we allocate but do + not use). This use of multiple block devices is accomplished as follows: + + Whatever the actual source of the allocated storage, the destination of the + image can be viewed in terms of one or more block devices, and on each + device, a list of sectors. To simplify matters, we only use contiguous, + PAGE_SIZE aligned sectors, like the swap code does. + + Since sector numbers on each bdev may well not start at 0, it makes much + more sense to use extents here. Contiguous ranges of pages can thus be + represented in the extents by contiguous values. + + Variations in block size are taken account of in transforming this data + into the parameters for bio submission. + + We can thus implement a layer of abstraction wherein the core of TuxOnIce + doesn't have to worry about which device we're currently writing to or + where in the device we are. It simply requests that the next page in the + pageset or header be written, leaving the details to this lower layer. + The lower layer remembers where in the sequence of devices and blocks each + pageset starts. The header always starts at the beginning of the allocated + storage. + + So extents are: + + struct extent { + unsigned long minimum, maximum; + struct extent *next; + } + + These are combined into chains of extents for a device: + + struct extent_chain { + int size; /* size of the extent ie sum (max-min+1) */ + int allocs, frees; + char *name; + struct extent *first, *last_touched; + }; + + For each bdev, we need to store a little more info (simplified definition): + + struct toi_bdev_info { + struct block_device *bdev; + + char uuid[17]; + dev_t dev_t; + int bmap_shift; + int blocks_per_page; + }; + + The uuid is the main means used to identify the device in the storage + image. This means we can cope with the dev_t representation of a device + changing between saving the image and restoring it, as may happen on some + bioses or in the LVM case. + + bmap_shift and blocks_per_page apply the effects of variations in blocks + per page settings for the filesystem and underlying bdev. For most + filesystems, these are the same, but for xfs, they can have independant + values. + + Combining these two structures together, we have everything we need to + record what devices and what blocks on each device are being used to + store the image, and to submit i/o using bio_submit. + + The last elements in the picture are a means of recording how the storage + is being used. + + We do this first and foremost by implementing a layer of abstraction on + top of the devices and extent chains which allows us to view however many + devices there might be as one long storage tape, with a single 'head' that + tracks a 'current position' on the tape: + + struct extent_iterate_state { + struct extent_chain *chains; + int num_chains; + int current_chain; + struct extent *current_extent; + unsigned long current_offset; + }; + + That is, *chains points to an array of size num_chains of extent chains. + For the filewriter, this is always a single chain. For the swapwriter, the + array is of size MAX_SWAPFILES. + + current_chain, current_extent and current_offset thus point to the current + index in the chains array (and into a matching array of struct + suspend_bdev_info), the current extent in that chain (to optimise access), + and the current value in the offset. + + The image is divided into three parts: + - The header + - Pageset 1 + - Pageset 2 + + The header always starts at the first device and first block. We know its + size before we begin to save the image because we carefully account for + everything that will be stored in it. + + The second pageset (LRU) is stored first. It begins on the next page after + the end of the header. + + The first pageset is stored second. It's start location is only known once + pageset2 has been saved, since pageset2 may be compressed as it is written. + This location is thus recorded at the end of saving pageset2. It is page + aligned also. + + Since this information is needed at resume time, and the location of extents + in memory will differ at resume time, this needs to be stored in a portable + way: + + struct extent_iterate_saved_state { + int chain_num; + int extent_num; + unsigned long offset; + }; + + We can thus implement a layer of abstraction wherein the core of TuxOnIce + doesn't have to worry about which device we're currently writing to or + where in the device we are. It simply requests that the next page in the + pageset or header be written, leaving the details to this layer, and + invokes the routines to remember and restore the position, without having + to worry about the details of how the data is arranged on disk or such like. + + c) Modules + + One aim in designing TuxOnIce was to make it flexible. We wanted to allow + for the implementation of different methods of transforming a page to be + written to disk and different methods of getting the pages stored. + + In early versions (the betas and perhaps Suspend1), compression support was + inlined in the image writing code, and the data structures and code for + managing swap were intertwined with the rest of the code. A number of people + had expressed interest in implementing image encryption, and alternative + methods of storing the image. + + In order to achieve this, TuxOnIce was given a modular design. + + A module is a single file which encapsulates the functionality needed + to transform a pageset of data (encryption or compression, for example), + or to write the pageset to a device. The former type of module is called + a 'page-transformer', the later a 'writer'. + + Modules are linked together in pipeline fashion. There may be zero or more + page transformers in a pipeline, and there is always exactly one writer. + The pipeline follows this pattern: + + --------------------------------- + | TuxOnIce Core | + --------------------------------- + | + | + --------------------------------- + | Page transformer 1 | + --------------------------------- + | + | + --------------------------------- + | Page transformer 2 | + --------------------------------- + | + | + --------------------------------- + | Writer | + --------------------------------- + + During the writing of an image, the core code feeds pages one at a time + to the first module. This module performs whatever transformations it + implements on the incoming data, completely consuming the incoming data and + feeding output in a similar manner to the next module. + + All routines are SMP safe, and the final result of the transformations is + written with an index (provided by the core) and size of the output by the + writer. As a result, we can have multithreaded I/O without needing to + worry about the sequence in which pages are written (or read). + + During reading, the pipeline works in the reverse direction. The core code + calls the first module with the address of a buffer which should be filled. + (Note that the buffer size is always PAGE_SIZE at this time). This module + will in turn request data from the next module and so on down until the + writer is made to read from the stored image. + + Part of definition of the structure of a module thus looks like this: + + int (*rw_init) (int rw, int stream_number); + int (*rw_cleanup) (int rw); + int (*write_chunk) (struct page *buffer_page); + int (*read_chunk) (struct page *buffer_page, int sync); + + It should be noted that the _cleanup routine may be called before the + full stream of data has been read or written. While writing the image, + the user may (depending upon settings) choose to abort suspending, and + if we are in the midst of writing the last portion of the image, a portion + of the second pageset may be reread. This may also happen if an error + occurs and we seek to abort the process of writing the image. + + The modular design is also useful in a number of other ways. It provides + a means where by we can add support for: + + - providing overall initialisation and cleanup routines; + - serialising configuration information in the image header; + - providing debugging information to the user; + - determining memory and image storage requirements; + - dis/enabling components at run-time; + - configuring the module (see below); + + ...and routines for writers specific to their work: + - Parsing a resume= location; + - Determining whether an image exists; + - Marking a resume as having been attempted; + - Invalidating an image; + + Since some parts of the core - the user interface and storage manager + support - have use for some of these functions, they are registered as + 'miscellaneous' modules as well. + + d) Sysfs data structures. + + This brings us naturally to support for configuring TuxOnIce. We desired to + provide a way to make TuxOnIce as flexible and configurable as possible. + The user shouldn't have to reboot just because they want to now hibernate to + a file instead of a partition, for example. + + To accomplish this, TuxOnIce implements a very generic means whereby the + core and modules can register new sysfs entries. All TuxOnIce entries use + a single _store and _show routine, both of which are found in + tuxonice_sysfs.c in the kernel/power directory. These routines handle the + most common operations - getting and setting the values of bits, integers, + longs, unsigned longs and strings in one place, and allow overrides for + customised get and set options as well as side-effect routines for all + reads and writes. + + When combined with some simple macros, a new sysfs entry can then be defined + in just a couple of lines: + + SYSFS_INT("progress_granularity", SYSFS_RW, &progress_granularity, 1, + 2048, 0, NULL), + + This defines a sysfs entry named "progress_granularity" which is rw and + allows the user to access an integer stored at &progress_granularity, giving + it a value between 1 and 2048 inclusive. + + Sysfs entries are registered under /sys/power/tuxonice, and entries for + modules are located in a subdirectory named after the module. + diff --git b/Documentation/power/tuxonice.txt b/Documentation/power/tuxonice.txt new file mode 100644 index 0000000..3bf0575 --- /dev/null +++ b/Documentation/power/tuxonice.txt @@ -0,0 +1,948 @@ + --- TuxOnIce, version 3.0 --- + +1. What is it? +2. Why would you want it? +3. What do you need to use it? +4. Why not just use the version already in the kernel? +5. How do you use it? +6. What do all those entries in /sys/power/tuxonice do? +7. How do you get support? +8. I think I've found a bug. What should I do? +9. When will XXX be supported? +10 How does it work? +11. Who wrote TuxOnIce? + +1. What is it? + + Imagine you're sitting at your computer, working away. For some reason, you + need to turn off your computer for a while - perhaps it's time to go home + for the day. When you come back to your computer next, you're going to want + to carry on where you left off. Now imagine that you could push a button and + have your computer store the contents of its memory to disk and power down. + Then, when you next start up your computer, it loads that image back into + memory and you can carry on from where you were, just as if you'd never + turned the computer off. You have far less time to start up, no reopening of + applications or finding what directory you put that file in yesterday. + That's what TuxOnIce does. + + TuxOnIce has a long heritage. It began life as work by Gabor Kuti, who, + with some help from Pavel Machek, got an early version going in 1999. The + project was then taken over by Florent Chabaud while still in alpha version + numbers. Nigel Cunningham came on the scene when Florent was unable to + continue, moving the project into betas, then 1.0, 2.0 and so on up to + the present series. During the 2.0 series, the name was contracted to + Suspend2 and the website suspend2.net created. Beginning around July 2007, + a transition to calling the software TuxOnIce was made, to seek to help + make it clear that TuxOnIce is more concerned with hibernation than suspend + to ram. + + Pavel Machek's swsusp code, which was merged around 2.5.17 retains the + original name, and was essentially a fork of the beta code until Rafael + Wysocki came on the scene in 2005 and began to improve it further. + +2. Why would you want it? + + Why wouldn't you want it? + + Being able to save the state of your system and quickly restore it improves + your productivity - you get a useful system in far less time than through + the normal boot process. You also get to be completely 'green', using zero + power, or as close to that as possible (the computer may still provide + minimal power to some devices, so they can initiate a power on, but that + will be the same amount of power as would be used if you told the computer + to shutdown. + +3. What do you need to use it? + + a. Kernel Support. + + i) The TuxOnIce patch. + + TuxOnIce is part of the Linux Kernel. This version is not part of Linus's + 2.6 tree at the moment, so you will need to download the kernel source and + apply the latest patch. Having done that, enable the appropriate options in + make [menu|x]config (under Power Management Options - look for "Enhanced + Hibernation"), compile and install your kernel. TuxOnIce works with SMP, + Highmem, preemption, fuse filesystems, x86-32, PPC and x86_64. + + TuxOnIce patches are available from http://tuxonice.net. + + ii) Compression support. + + Compression support is implemented via the cryptoapi. You will therefore want + to select any Cryptoapi transforms that you want to use on your image from + the Cryptoapi menu while configuring your kernel. We recommend the use of the + LZO compression method - it is very fast and still achieves good compression. + + You can also tell TuxOnIce to write its image to an encrypted and/or + compressed filesystem/swap partition. In that case, you don't need to do + anything special for TuxOnIce when it comes to kernel configuration. + + iii) Configuring other options. + + While you're configuring your kernel, try to configure as much as possible + to build as modules. We recommend this because there are a number of drivers + that are still in the process of implementing proper power management + support. In those cases, the best way to work around their current lack is + to build them as modules and remove the modules while hibernating. You might + also bug the driver authors to get their support up to speed, or even help! + + b. Storage. + + i) Swap. + + TuxOnIce can store the hibernation image in your swap partition, a swap file or + a combination thereof. Whichever combination you choose, you will probably + want to create enough swap space to store the largest image you could have, + plus the space you'd normally use for swap. A good rule of thumb would be + to calculate the amount of swap you'd want without using TuxOnIce, and then + add the amount of memory you have. This swapspace can be arranged in any way + you'd like. It can be in one partition or file, or spread over a number. The + only requirement is that they be active when you start a hibernation cycle. + + There is one exception to this requirement. TuxOnIce has the ability to turn + on one swap file or partition at the start of hibernating and turn it back off + at the end. If you want to ensure you have enough memory to store a image + when your memory is fully used, you might want to make one swap partition or + file for 'normal' use, and another for TuxOnIce to activate & deactivate + automatically. (Further details below). + + ii) Normal files. + + TuxOnIce includes a 'file allocator'. The file allocator can store your + image in a simple file. Since Linux has the concept of everything being a + file, this is more powerful than it initially sounds. If, for example, you + were to set up a network block device file, you could hibernate to a network + server. This has been tested and works to a point, but nbd itself isn't + stateless enough for our purposes. + + Take extra care when setting up the file allocator. If you just type + commands without thinking and then try to hibernate, you could cause + irreversible corruption on your filesystems! Make sure you have backups. + + Most people will only want to hibernate to a local file. To achieve that, do + something along the lines of: + + echo "TuxOnIce" > /hibernation-file + dd if=/dev/zero bs=1M count=512 >> /hibernation-file + + This will create a 512MB file called /hibernation-file. To get TuxOnIce to use + it: + + echo /hibernation-file > /sys/power/tuxonice/file/target + + Then + + cat /sys/power/tuxonice/resume + + Put the results of this into your bootloader's configuration (see also step + C, below): + + ---EXAMPLE-ONLY-DON'T-COPY-AND-PASTE--- + # cat /sys/power/tuxonice/resume + file:/dev/hda2:0x1e001 + + In this example, we would edit the append= line of our lilo.conf|menu.lst + so that it included: + + resume=file:/dev/hda2:0x1e001 + ---EXAMPLE-ONLY-DON'T-COPY-AND-PASTE--- + + For those who are thinking 'Could I make the file sparse?', the answer is + 'No!'. At the moment, there is no way for TuxOnIce to fill in the holes in + a sparse file while hibernating. In the longer term (post merge!), I'd like + to change things so that the file could be dynamically resized and have + holes filled as needed. Right now, however, that's not possible and not a + priority. + + c. Bootloader configuration. + + Using TuxOnIce also requires that you add an extra parameter to + your lilo.conf or equivalent. Here's an example for a swap partition: + + append="resume=swap:/dev/hda1" + + This would tell TuxOnIce that /dev/hda1 is a swap partition you + have. TuxOnIce will use the swap signature of this partition as a + pointer to your data when you hibernate. This means that (in this example) + /dev/hda1 doesn't need to be _the_ swap partition where all of your data + is actually stored. It just needs to be a swap partition that has a + valid signature. + + You don't need to have a swap partition for this purpose. TuxOnIce + can also use a swap file, but usage is a little more complex. Having made + your swap file, turn it on and do + + cat /sys/power/tuxonice/swap/headerlocations + + (this assumes you've already compiled your kernel with TuxOnIce + support and booted it). The results of the cat command will tell you + what you need to put in lilo.conf: + + For swap partitions like /dev/hda1, simply use resume=/dev/hda1. + For swapfile `swapfile`, use resume=swap:/dev/hda2:0x242d. + + If the swapfile changes for any reason (it is moved to a different + location, it is deleted and recreated, or the filesystem is + defragmented) then you will have to check + /sys/power/tuxonice/swap/headerlocations for a new resume_block value. + + Once you've compiled and installed the kernel and adjusted your bootloader + configuration, you should only need to reboot for the most basic part + of TuxOnIce to be ready. + + If you only compile in the swap allocator, or only compile in the file + allocator, you don't need to add the "swap:" part of the resume= + parameters above. resume=/dev/hda2:0x242d will work just as well. If you + have compiled both and your storage is on swap, you can also use this + format (the swap allocator is the default allocator). + + When compiling your kernel, one of the options in the 'Power Management + Support' menu, just above the 'Enhanced Hibernation (TuxOnIce)' entry is + called 'Default resume partition'. This can be used to set a default value + for the resume= parameter. + + d. The hibernate script. + + Since the driver model in 2.6 kernels is still being developed, you may need + to do more than just configure TuxOnIce. Users of TuxOnIce usually start the + process via a script which prepares for the hibernation cycle, tells the + kernel to do its stuff and then restore things afterwards. This script might + involve: + + - Switching to a text console and back if X doesn't like the video card + status on resume. + - Un/reloading drivers that don't play well with hibernation. + + Note that you might not be able to unload some drivers if there are + processes using them. You might have to kill off processes that hold + devices open. Hint: if your X server accesses an USB mouse, doing a + 'chvt' to a text console releases the device and you can unload the + module. + + Check out the latest script (available on tuxonice.net). + + e. The userspace user interface. + + TuxOnIce has very limited support for displaying status if you only apply + the kernel patch - it can printk messages, but that is all. In addition, + some of the functions mentioned in this document (such as cancelling a cycle + or performing interactive debugging) are unavailable. To utilise these + functions, or simply get a nice display, you need the 'userui' component. + Userui comes in three flavours, usplash, fbsplash and text. Text should + work on any console. Usplash and fbsplash require the appropriate + (distro specific?) support. + + To utilise a userui, TuxOnIce just needs to be told where to find the + userspace binary: + + echo "/usr/local/sbin/tuxoniceui_fbsplash" > /sys/power/tuxonice/user_interface/program + + The hibernate script can do this for you, and a default value for this + setting can be configured when compiling the kernel. This path is also + stored in the image header, so if you have an initrd or initramfs, you can + use the userui during the first part of resuming (prior to the atomic + restore) by putting the binary in the same path in your initrd/ramfs. + Alternatively, you can put it in a different location and do an echo + similar to the above prior to the echo > do_resume. The value saved in the + image header will then be ignored. + +4. Why not just use the version already in the kernel? + + The version in the vanilla kernel has a number of drawbacks. The most + serious of these are: + - it has a maximum image size of 1/2 total memory; + - it doesn't allocate storage until after it has snapshotted memory. + This means that you can't be sure hibernating will work until you + see it start to write the image; + - it does not allow you to press escape to cancel a cycle; + - it does not allow you to press escape to cancel resuming; + - it does not allow you to automatically swapon a file when + starting a cycle; + - it does not allow you to use multiple swap partitions or files; + - it does not allow you to use ordinary files; + - it just invalidates an image and continues to boot if you + accidentally boot the wrong kernel after hibernating; + - it doesn't support any sort of nice display while hibernating; + - it is moving toward requiring that you have an initrd/initramfs + to ever have a hope of resuming (uswsusp). While uswsusp will + address some of the concerns above, it won't address all of them, + and will be more complicated to get set up; + - it doesn't have support for suspend-to-both (write a hibernation + image, then suspend to ram; I think this is known as ReadySafe + under M$). + +5. How do you use it? + + A hibernation cycle can be started directly by doing: + + echo > /sys/power/tuxonice/do_hibernate + + In practice, though, you'll probably want to use the hibernate script + to unload modules, configure the kernel the way you like it and so on. + In that case, you'd do (as root): + + hibernate + + See the hibernate script's man page for more details on the options it + takes. + + If you're using the text or splash user interface modules, one feature of + TuxOnIce that you might find useful is that you can press Escape at any time + during hibernating, and the process will be aborted. + + Due to the way hibernation works, this means you'll have your system back and + perfectly usable almost instantly. The only exception is when it's at the + very end of writing the image. Then it will need to reload a small (usually + 4-50MBs, depending upon the image characteristics) portion first. + + Likewise, when resuming, you can press escape and resuming will be aborted. + The computer will then powerdown again according to settings at that time for + the powerdown method or rebooting. + + You can change the settings for powering down while the image is being + written by pressing 'R' to toggle rebooting and 'O' to toggle between + suspending to ram and powering down completely). + + If you run into problems with resuming, adding the "noresume" option to + the kernel command line will let you skip the resume step and recover your + system. This option shouldn't normally be needed, because TuxOnIce modifies + the image header prior to the atomic restore, and will thus prompt you + if it detects that you've tried to resume an image before (this flag is + removed if you press Escape to cancel a resume, so you won't be prompted + then). + + Recent kernels (2.6.24 onwards) add support for resuming from a different + kernel to the one that was hibernated (thanks to Rafael for his work on + this - I've just embraced and enhanced the support for TuxOnIce). This + should further reduce the need for you to use the noresume option. + +6. What do all those entries in /sys/power/tuxonice do? + + /sys/power/tuxonice is the directory which contains files you can use to + tune and configure TuxOnIce to your liking. The exact contents of + the directory will depend upon the version of TuxOnIce you're + running and the options you selected at compile time. In the following + descriptions, names in brackets refer to compile time options. + (Note that they're all dependant upon you having selected CONFIG_TUXONICE + in the first place!). + + Since the values of these settings can open potential security risks, the + writeable ones are accessible only to the root user. You may want to + configure sudo to allow you to invoke your hibernate script as an ordinary + user. + + - alloc/failure_test + + This debugging option provides a way of testing TuxOnIce's handling of + memory allocation failures. Each allocation type that TuxOnIce makes has + been given a unique number (see the source code). Echo the appropriate + number into this entry, and when TuxOnIce attempts to do that allocation, + it will pretend there was a failure and act accordingly. + + - alloc/find_max_mem_allocated + + This debugging option will cause TuxOnIce to find the maximum amount of + memory it used during a cycle, and report that information in debugging + information at the end of the cycle. + + - alt_resume_param + + Instead of powering down after writing a hibernation image, TuxOnIce + supports resuming from a different image. This entry lets you set the + location of the signature for that image (the resume= value you'd use + for it). Using an alternate image and keep_image mode, you can do things + like using an alternate image to power down an uninterruptible power + supply. + + - block_io/target_outstanding_io + + This value controls the amount of memory that the block I/O code says it + needs when the core code is calculating how much memory is needed for + hibernating and for resuming. It doesn't directly control the amount of + I/O that is submitted at any one time - that depends on the amount of + available memory (we may have more available than we asked for), the + throughput that is being achieved and the ability of the CPU to keep up + with disk throughput (particularly where we're compressing pages). + + - checksum/enabled + + Use cryptoapi hashing routines to verify that Pageset2 pages don't change + while we're saving the first part of the image, and to get any pages that + do change resaved in the atomic copy. This should normally not be needed, + but if you're seeing issues, please enable this. If your issues stop you + being able to resume, enable this option, hibernate and cancel the cycle + after the atomic copy is done. If the debugging info shows a non-zero + number of pages resaved, please report this to Nigel. + + - compression/algorithm + + Set the cryptoapi algorithm used for compressing the image. + + - compression/expected_compression + + These values allow you to set an expected compression ratio, which TuxOnice + will use in calculating whether it meets constraints on the image size. If + this expected compression ratio is not attained, the hibernation cycle will + abort, so it is wise to allow some spare. You can see what compression + ratio is achieved in the logs after hibernating. + + - debug_info: + + This file returns information about your configuration that may be helpful + in diagnosing problems with hibernating. + + - did_suspend_to_both: + + This file can be used when you hibernate with powerdown method 3 (ie suspend + to ram after writing the image). There can be two outcomes in this case. We + can resume from the suspend-to-ram before the battery runs out, or we can run + out of juice and and up resuming like normal. This entry lets you find out, + post resume, which way we went. If the value is 1, we resumed from suspend + to ram. This can be useful when actions need to be run post suspend-to-ram + that don't need to be run if we did the normal resume from power off. + + - do_hibernate: + + When anything is written to this file, the kernel side of TuxOnIce will + begin to attempt to write an image to disk and power down. You'll normally + want to run the hibernate script instead, to get modules unloaded first. + + - do_resume: + + When anything is written to this file TuxOnIce will attempt to read and + restore an image. If there is no image, it will return almost immediately. + If an image exists, the echo > will never return. Instead, the original + kernel context will be restored and the original echo > do_hibernate will + return. + + - */enabled + + These option can be used to temporarily disable various parts of TuxOnIce. + + - extra_pages_allowance + + When TuxOnIce does its atomic copy, it calls the driver model suspend + and resume methods. If you have DRI enabled with a driver such as fglrx, + this can result in the driver allocating a substantial amount of memory + for storing its state. Extra_pages_allowance tells TuxOnIce how much + extra memory it should ensure is available for those allocations. If + your attempts at hibernating end with a message in dmesg indicating that + insufficient extra pages were allowed, you need to increase this value. + + - file/target: + + Read this value to get the current setting. Write to it to point TuxOnice + at a new storage location for the file allocator. See section 3.b.ii above + for details of how to set up the file allocator. + + - freezer_test + + This entry can be used to get TuxOnIce to just test the freezer and prepare + an image without actually doing a hibernation cycle. It is useful for + diagnosing freezing and image preparation issues. + + - full_pageset2 + + TuxOnIce divides the pages that are stored in an image into two sets. The + difference between the two sets is that pages in pageset 1 are atomically + copied, and pages in pageset 2 are written to disk without being copied + first. A page CAN be written to disk without being copied first if and only + if its contents will not be modified or used at any time after userspace + processes are frozen. A page MUST be in pageset 1 if its contents are + modified or used at any time after userspace processes have been frozen. + + Normally (ie if this option is enabled), TuxOnIce will put all pages on the + per-zone LRUs in pageset2, then remove those pages used by any userspace + user interface helper and TuxOnIce storage manager that are running, + together with pages used by the GEM memory manager introduced around 2.6.28 + kernels. + + If this option is disabled, a much more conservative approach will be taken. + The only pages in pageset2 will be those belonging to userspace processes, + with the exclusion of those belonging to the TuxOnIce userspace helpers + mentioned above. This will result in a much smaller pageset2, and will + therefore result in smaller images than are possible with this option + enabled. + + - ignore_rootfs + + TuxOnIce records which device is mounted as the root filesystem when + writing the hibernation image. It will normally check at resume time that + this device isn't already mounted - that would be a cause of filesystem + corruption. In some particular cases (RAM based root filesystems), you + might want to disable this check. This option allows you to do that. + + - image_exists: + + Can be used in a script to determine whether a valid image exists at the + location currently pointed to by resume=. Returns up to three lines. + The first is whether an image exists (-1 for unsure, otherwise 0 or 1). + If an image eixsts, additional lines will return the machine and version. + Echoing anything to this entry removes any current image. + + - image_size_limit: + + The maximum size of hibernation image written to disk, measured in megabytes + (1024*1024). + + - last_result: + + The result of the last hibernation cycle, as defined in + include/linux/suspend-debug.h with the values SUSPEND_ABORTED to + SUSPEND_KEPT_IMAGE. This is a bitmask. + + - late_cpu_hotplug: + + This sysfs entry controls whether cpu hotplugging is done - as normal - just + before (unplug) and after (replug) the atomic copy/restore (so that all + CPUs/cores are available for multithreaded I/O). The alternative is to + unplug all secondary CPUs/cores at the start of hibernating/resuming, and + replug them at the end of resuming. No multithreaded I/O will be possible in + this configuration, but the odd machine has been reported to require it. + + - lid_file: + + This determines which ACPI button file we look in to determine whether the + lid is open or closed after resuming from suspend to disk or power off. + If the entry is set to "lid/LID", we'll open /proc/acpi/button/lid/LID/state + and check its contents at the appropriate moment. See post_wake_state below + for more details on how this entry is used. + + - log_everything (CONFIG_PM_DEBUG): + + Setting this option results in all messages printed being logged. Normally, + only a subset are logged, so as to not slow the process and not clutter the + logs. Useful for debugging. It can be toggled during a cycle by pressing + 'L'. + + - no_load_direct: + + This is a debugging option. If, when loading the atomically copied pages of + an image, TuxOnIce finds that the destination address for a page is free, + it will normally allocate the image, load the data directly into that + address and skip it in the atomic restore. If this option is disabled, the + page will be loaded somewhere else and atomically restored like other pages. + + - no_flusher_thread: + + When doing multithreaded I/O (see below), the first online CPU can be used + to _just_ submit compressed pages when writing the image, rather than + compressing and submitting data. This option is normally disabled, but has + been included because Nigel would like to see whether it will be more useful + as the number of cores/cpus in computers increases. + + - no_multithreaded_io: + + TuxOnIce will normally create one thread per cpu/core on your computer, + each of which will then perform I/O. This will generally result in + throughput that's the maximum the storage medium can handle. There + shouldn't be any reason to disable multithreaded I/O now, but this option + has been retained for debugging purposes. + + - no_pageset2 + + See the entry for full_pageset2 above for an explanation of pagesets. + Enabling this option causes TuxOnIce to do an atomic copy of all pages, + thereby limiting the maximum image size to 1/2 of memory, as swsusp does. + + - no_pageset2_if_unneeded + + See the entry for full_pageset2 above for an explanation of pagesets. + Enabling this option causes TuxOnIce to act like no_pageset2 was enabled + if and only it isn't needed anyway. This option may still make TuxOnIce + less reliable because pageset2 pages are normally used to store the + atomic copy - drivers that want to do allocations of larger amounts of + memory in one shot will be more likely to find that those amounts aren't + available if this option is enabled. + + - pause_between_steps (CONFIG_PM_DEBUG): + + This option is used during debugging, to make TuxOnIce pause between + each step of the process. It is ignored when the nice display is on. + + - post_wake_state: + + TuxOnIce provides support for automatically waking after a user-selected + delay, and using a different powerdown method if the lid is still closed. + (Yes, we're assuming a laptop). This entry lets you choose what state + should be entered next. The values are those described under + powerdown_method, below. It can be used to suspend to RAM after hibernating, + then powerdown properly (say) 20 minutes. It can also be used to power down + properly, then wake at (say) 6.30am and suspend to RAM until you're ready + to use the machine. + + - powerdown_method: + + Used to select a method by which TuxOnIce should powerdown after writing the + image. Currently: + + 0: Don't use ACPI to power off. + 3: Attempt to enter Suspend-to-ram. + 4: Attempt to enter ACPI S4 mode. + 5: Attempt to power down via ACPI S5 mode. + + Note that these options are highly dependant upon your hardware & software: + + 3: When succesful, your machine suspends to ram instead of powering off. + The advantage of using this mode is that it doesn't matter whether your + battery has enough charge to make it through to your next resume. If it + lasts, you will simply resume from suspend to ram (and the image on disk + will be discarded). If the battery runs out, you will resume from disk + instead. The disadvantage is that it takes longer than a normal + suspend-to-ram to enter the state, since the suspend-to-disk image needs + to be written first. + 4/5: When successful, your machine will be off and comsume (almost) no power. + But it might still react to some external events like opening the lid or + trafic on a network or usb device. For the bios, resume is then the same + as warm boot, similar to a situation where you used the command `reboot' + to reboot your machine. If your machine has problems on warm boot or if + you want to protect your machine with the bios password, this is probably + not the right choice. Mode 4 may be necessary on some machines where ACPI + wake up methods need to be run to properly reinitialise hardware after a + hibernation cycle. + 0: Switch the machine completely off. The only possible wakeup is the power + button. For the bios, resume is then the same as a cold boot, in + particular you would have to provide your bios boot password if your + machine uses that feature for booting. + + - progressbar_granularity_limit: + + This option can be used to limit the granularity of the progress bar + displayed with a bootsplash screen. The value is the maximum number of + steps. That is, 10 will make the progress bar jump in 10% increments. + + - reboot: + + This option causes TuxOnIce to reboot rather than powering down + at the end of saving an image. It can be toggled during a cycle by pressing + 'R'. + + - resume: + + This sysfs entry can be used to read and set the location in which TuxOnIce + will look for the signature of an image - the value set using resume= at + boot time or CONFIG_PM_STD_PARTITION ("Default resume partition"). By + writing to this file as well as modifying your bootloader's configuration + file (eg menu.lst), you can set or reset the location of your image or the + method of storing the image without rebooting. + + - replace_swsusp (CONFIG_TOI_REPLACE_SWSUSP): + + This option makes + + echo disk > /sys/power/state + + activate TuxOnIce instead of swsusp. Regardless of whether this option is + enabled, any invocation of swsusp's resume time trigger will cause TuxOnIce + to check for an image too. This is due to the fact that at resume time, we + can't know whether this option was enabled until we see if an image is there + for us to resume from. (And when an image exists, we don't care whether we + did replace swsusp anyway - we just want to resume). + + - resume_commandline: + + This entry can be read after resuming to see the commandline that was used + when resuming began. You might use this to set up two bootloader entries + that are the same apart from the fact that one includes a extra append= + argument "at_work=1". You could then grep resume_commandline in your + post-resume scripts and configure networking (for example) differently + depending upon whether you're at home or work. resume_commandline can be + set to arbitrary text if you wish to remove sensitive contents. + + - swap/swapfilename: + + This entry is used to specify the swapfile or partition that + TuxOnIce will attempt to swapon/swapoff automatically. Thus, if + I normally use /dev/hda1 for swap, and want to use /dev/hda2 for specifically + for my hibernation image, I would + + echo /dev/hda2 > /sys/power/tuxonice/swap/swapfile + + /dev/hda2 would then be automatically swapon'd and swapoff'd. Note that the + swapon and swapoff occur while other processes are frozen (including kswapd) + so this swap file will not be used up when attempting to free memory. The + parition/file is also given the highest priority, so other swapfiles/partitions + will only be used to save the image when this one is filled. + + The value of this file is used by headerlocations along with any currently + activated swapfiles/partitions. + + - swap/headerlocations: + + This option tells you the resume= options to use for swap devices you + currently have activated. It is particularly useful when you only want to + use a swap file to store your image. See above for further details. + + - test_bio + + This is a debugging option. When enabled, TuxOnIce will not hibernate. + Instead, when asked to write an image, it will skip the atomic copy, + just doing the writing of the image and then returning control to the + user at the point where it would have powered off. This is useful for + testing throughput in different configurations. + + - test_filter_speed + + This is a debugging option. When enabled, TuxOnIce will not hibernate. + Instead, when asked to write an image, it will not write anything or do + an atomic copy, but will only run any enabled compression algorithm on the + data that would have been written (the source pages of the atomic copy in + the case of pageset 1). This is useful for comparing the performance of + compression algorithms and for determining the extent to which an upgrade + to your storage method would improve hibernation speed. + + - user_interface/debug_sections (CONFIG_PM_DEBUG): + + This value, together with the console log level, controls what debugging + information is displayed. The console log level determines the level of + detail, and this value determines what detail is displayed. This value is + a bit vector, and the meaning of the bits can be found in the kernel tree + in include/linux/tuxonice.h. It can be overridden using the kernel's + command line option suspend_dbg. + + - user_interface/default_console_level (CONFIG_PM_DEBUG): + + This determines the value of the console log level at the start of a + hibernation cycle. If debugging is compiled in, the console log level can be + changed during a cycle by pressing the digit keys. Meanings are: + + 0: Nice display. + 1: Nice display plus numerical progress. + 2: Errors only. + 3: Low level debugging info. + 4: Medium level debugging info. + 5: High level debugging info. + 6: Verbose debugging info. + + - user_interface/enable_escape: + + Setting this to "1" will enable you abort a hibernation cycle or resuming by + pressing escape, "0" (default) disables this feature. Note that enabling + this option means that you cannot initiate a hibernation cycle and then walk + away from your computer, expecting it to be secure. With feature disabled, + you can validly have this expectation once TuxOnice begins to write the + image to disk. (Prior to this point, it is possible that TuxOnice might + about because of failure to freeze all processes or because constraints + on its ability to save the image are not met). + + - user_interface/program + + This entry is used to tell TuxOnice what userspace program to use for + providing a user interface while hibernating. The program uses a netlink + socket to pass messages back and forward to the kernel, allowing all of the + functions formerly implemented in the kernel user interface components. + + - version: + + The version of TuxOnIce you have compiled into the currently running kernel. + + - wake_alarm_dir: + + As mentioned above (post_wake_state), TuxOnIce supports automatically waking + after some delay. This entry allows you to select which wake alarm to use. + It should contain the value "rtc0" if you're wanting to use + /sys/class/rtc/rtc0. + + - wake_delay: + + This value determines the delay from the end of writing the image until the + wake alarm is triggered. You can set an absolute time by writing the desired + time into /sys/class/rtc//wakealarm and leaving these values + empty. + + Note that for the wakeup to actually occur, you may need to modify entries + in /proc/acpi/wakeup. This is done by echoing the name of the button in the + first column (eg PBTN) into the file. + +7. How do you get support? + + Glad you asked. TuxOnIce is being actively maintained and supported + by Nigel (the guy doing most of the kernel coding at the moment), Bernard + (who maintains the hibernate script and userspace user interface components) + and its users. + + Resources availble include HowTos, FAQs and a Wiki, all available via + tuxonice.net. You can find the mailing lists there. + +8. I think I've found a bug. What should I do? + + By far and a way, the most common problems people have with TuxOnIce + related to drivers not having adequate power management support. In this + case, it is not a bug with TuxOnIce, but we can still help you. As we + mentioned above, such issues can usually be worked around by building the + functionality as modules and unloading them while hibernating. Please visit + the Wiki for up-to-date lists of known issues and work arounds. + + If this information doesn't help, try running: + + hibernate --bug-report + + ..and sending the output to the users mailing list. + + Good information on how to provide us with useful information from an + oops is found in the file REPORTING-BUGS, in the top level directory + of the kernel tree. If you get an oops, please especially note the + information about running what is printed on the screen through ksymoops. + The raw information is useless. + +9. When will XXX be supported? + + If there's a feature missing from TuxOnIce that you'd like, feel free to + ask. We try to be obliging, within reason. + + Patches are welcome. Please send to the list. + +10. How does it work? + + TuxOnIce does its work in a number of steps. + + a. Freezing system activity. + + The first main stage in hibernating is to stop all other activity. This is + achieved in stages. Processes are considered in fours groups, which we will + describe in reverse order for clarity's sake: Threads with the PF_NOFREEZE + flag, kernel threads without this flag, userspace processes with the + PF_SYNCTHREAD flag and all other processes. The first set (PF_NOFREEZE) are + untouched by the refrigerator code. They are allowed to run during hibernating + and resuming, and are used to support user interaction, storage access or the + like. Other kernel threads (those unneeded while hibernating) are frozen last. + This leaves us with userspace processes that need to be frozen. When a + process enters one of the *_sync system calls, we set a PF_SYNCTHREAD flag on + that process for the duration of that call. Processes that have this flag are + frozen after processes without it, so that we can seek to ensure that dirty + data is synced to disk as quickly as possible in a situation where other + processes may be submitting writes at the same time. Freezing the processes + that are submitting data stops new I/O from being submitted. Syncthreads can + then cleanly finish their work. So the order is: + + - Userspace processes without PF_SYNCTHREAD or PF_NOFREEZE; + - Userspace processes with PF_SYNCTHREAD (they won't have NOFREEZE); + - Kernel processes without PF_NOFREEZE. + + b. Eating memory. + + For a successful hibernation cycle, you need to have enough disk space to store the + image and enough memory for the various limitations of TuxOnIce's + algorithm. You can also specify a maximum image size. In order to attain + to those constraints, TuxOnIce may 'eat' memory. If, after freezing + processes, the constraints aren't met, TuxOnIce will thaw all the + other processes and begin to eat memory until its calculations indicate + the constraints are met. It will then freeze processes again and recheck + its calculations. + + c. Allocation of storage. + + Next, TuxOnIce allocates the storage that will be used to save + the image. + + The core of TuxOnIce knows nothing about how or where pages are stored. We + therefore request the active allocator (remember you might have compiled in + more than one!) to allocate enough storage for our expect image size. If + this request cannot be fulfilled, we eat more memory and try again. If it + is fulfiled, we seek to allocate additional storage, just in case our + expected compression ratio (if any) isn't achieved. This time, however, we + just continue if we can't allocate enough storage. + + If these calls to our allocator change the characteristics of the image + such that we haven't allocated enough memory, we also loop. (The allocator + may well need to allocate space for its storage information). + + d. Write the first part of the image. + + TuxOnIce stores the image in two sets of pages called 'pagesets'. + Pageset 2 contains pages on the active and inactive lists; essentially + the page cache. Pageset 1 contains all other pages, including the kernel. + We use two pagesets for one important reason: We need to make an atomic copy + of the kernel to ensure consistency of the image. Without a second pageset, + that would limit us to an image that was at most half the amount of memory + available. Using two pagesets allows us to store a full image. Since pageset + 2 pages won't be needed in saving pageset 1, we first save pageset 2 pages. + We can then make our atomic copy of the remaining pages using both pageset 2 + pages and any other pages that are free. While saving both pagesets, we are + careful not to corrupt the image. Among other things, we use lowlevel block + I/O routines that don't change the pagecache contents. + + The next step, then, is writing pageset 2. + + e. Suspending drivers and storing processor context. + + Having written pageset2, TuxOnIce calls the power management functions to + notify drivers of the hibernation, and saves the processor state in preparation + for the atomic copy of memory we are about to make. + + f. Atomic copy. + + At this stage, everything else but the TuxOnIce code is halted. Processes + are frozen or idling, drivers are quiesced and have stored (ideally and where + necessary) their configuration in memory we are about to atomically copy. + In our lowlevel architecture specific code, we have saved the CPU state. + We can therefore now do our atomic copy before resuming drivers etc. + + g. Save the atomic copy (pageset 1). + + TuxOnice can then write the atomic copy of the remaining pages. Since we + have copied the pages into other locations, we can continue to use the + normal block I/O routines without fear of corruption our image. + + f. Save the image header. + + Nearly there! We save our settings and other parameters needed for + reloading pageset 1 in an 'image header'. We also tell our allocator to + serialise its data at this stage, so that it can reread the image at resume + time. + + g. Set the image header. + + Finally, we edit the header at our resume= location. The signature is + changed by the allocator to reflect the fact that an image exists, and to + point to the start of that data if necessary (swap allocator). + + h. Power down. + + Or reboot if we're debugging and the appropriate option is selected. + + Whew! + + Reloading the image. + -------------------- + + Reloading the image is essentially the reverse of all the above. We load + our copy of pageset 1, being careful to choose locations that aren't going + to be overwritten as we copy it back (We start very early in the boot + process, so there are no other processes to quiesce here). We then copy + pageset 1 back to its original location in memory and restore the process + context. We are now running with the original kernel. Next, we reload the + pageset 2 pages, free the memory and swap used by TuxOnIce, restore + the pageset header and restart processes. Sounds easy in comparison to + hibernating, doesn't it! + + There is of course more to TuxOnIce than this, but this explanation + should be a good start. If there's interest, I'll write further + documentation on range pages and the low level I/O. + +11. Who wrote TuxOnIce? + + (Answer based on the writings of Florent Chabaud, credits in files and + Nigel's limited knowledge; apologies to anyone missed out!) + + The main developers of TuxOnIce have been... + + Gabor Kuti + Pavel Machek + Florent Chabaud + Bernard Blackham + Nigel Cunningham + + Significant portions of swsusp, the code in the vanilla kernel which + TuxOnIce enhances, have been worked on by Rafael Wysocki. Thanks should + also be expressed to him. + + The above mentioned developers have been aided in their efforts by a host + of hundreds, if not thousands of testers and people who have submitted bug + fixes & suggestions. Of special note are the efforts of Michael Frank, who + had his computers repetitively hibernate and resume for literally tens of + thousands of cycles and developed scripts to stress the system and test + TuxOnIce far beyond the point most of us (Nigel included!) would consider + testing. His efforts have contributed as much to TuxOnIce as any of the + names above. diff --git b/Documentation/scheduler/sched-BFS.txt b/Documentation/scheduler/sched-BFS.txt new file mode 100644 index 0000000..c028200 --- /dev/null +++ b/Documentation/scheduler/sched-BFS.txt @@ -0,0 +1,351 @@ +BFS - The Brain Fuck Scheduler by Con Kolivas. + +Goals. + +The goal of the Brain Fuck Scheduler, referred to as BFS from here on, is to +completely do away with the complex designs of the past for the cpu process +scheduler and instead implement one that is very simple in basic design. +The main focus of BFS is to achieve excellent desktop interactivity and +responsiveness without heuristics and tuning knobs that are difficult to +understand, impossible to model and predict the effect of, and when tuned to +one workload cause massive detriment to another. + + +Design summary. + +BFS is best described as a single runqueue, O(n) lookup, earliest effective +virtual deadline first design, loosely based on EEVDF (earliest eligible virtual +deadline first) and my previous Staircase Deadline scheduler. Each component +shall be described in order to understand the significance of, and reasoning for +it. The codebase when the first stable version was released was approximately +9000 lines less code than the existing mainline linux kernel scheduler (in +2.6.31). This does not even take into account the removal of documentation and +the cgroups code that is not used. + +Design reasoning. + +The single runqueue refers to the queued but not running processes for the +entire system, regardless of the number of CPUs. The reason for going back to +a single runqueue design is that once multiple runqueues are introduced, +per-CPU or otherwise, there will be complex interactions as each runqueue will +be responsible for the scheduling latency and fairness of the tasks only on its +own runqueue, and to achieve fairness and low latency across multiple CPUs, any +advantage in throughput of having CPU local tasks causes other disadvantages. +This is due to requiring a very complex balancing system to at best achieve some +semblance of fairness across CPUs and can only maintain relatively low latency +for tasks bound to the same CPUs, not across them. To increase said fairness +and latency across CPUs, the advantage of local runqueue locking, which makes +for better scalability, is lost due to having to grab multiple locks. + +A significant feature of BFS is that all accounting is done purely based on CPU +used and nowhere is sleep time used in any way to determine entitlement or +interactivity. Interactivity "estimators" that use some kind of sleep/run +algorithm are doomed to fail to detect all interactive tasks, and to falsely tag +tasks that aren't interactive as being so. The reason for this is that it is +close to impossible to determine that when a task is sleeping, whether it is +doing it voluntarily, as in a userspace application waiting for input in the +form of a mouse click or otherwise, or involuntarily, because it is waiting for +another thread, process, I/O, kernel activity or whatever. Thus, such an +estimator will introduce corner cases, and more heuristics will be required to +cope with those corner cases, introducing more corner cases and failed +interactivity detection and so on. Interactivity in BFS is built into the design +by virtue of the fact that tasks that are waking up have not used up their quota +of CPU time, and have earlier effective deadlines, thereby making it very likely +they will preempt any CPU bound task of equivalent nice level. See below for +more information on the virtual deadline mechanism. Even if they do not preempt +a running task, because the rr interval is guaranteed to have a bound upper +limit on how long a task will wait for, it will be scheduled within a timeframe +that will not cause visible interface jitter. + + +Design details. + +Task insertion. + +BFS inserts tasks into each relevant queue as an O(1) insertion into a double +linked list. On insertion, *every* running queue is checked to see if the newly +queued task can run on any idle queue, or preempt the lowest running task on the +system. This is how the cross-CPU scheduling of BFS achieves significantly lower +latency per extra CPU the system has. In this case the lookup is, in the worst +case scenario, O(n) where n is the number of CPUs on the system. + +Data protection. + +BFS has one single lock protecting the process local data of every task in the +global queue. Thus every insertion, removal and modification of task data in the +global runqueue needs to grab the global lock. However, once a task is taken by +a CPU, the CPU has its own local data copy of the running process' accounting +information which only that CPU accesses and modifies (such as during a +timer tick) thus allowing the accounting data to be updated lockless. Once a +CPU has taken a task to run, it removes it from the global queue. Thus the +global queue only ever has, at most, + + (number of tasks requesting cpu time) - (number of logical CPUs) + 1 + +tasks in the global queue. This value is relevant for the time taken to look up +tasks during scheduling. This will increase if many tasks with CPU affinity set +in their policy to limit which CPUs they're allowed to run on if they outnumber +the number of CPUs. The +1 is because when rescheduling a task, the CPU's +currently running task is put back on the queue. Lookup will be described after +the virtual deadline mechanism is explained. + +Virtual deadline. + +The key to achieving low latency, scheduling fairness, and "nice level" +distribution in BFS is entirely in the virtual deadline mechanism. The one +tunable in BFS is the rr_interval, or "round robin interval". This is the +maximum time two SCHED_OTHER (or SCHED_NORMAL, the common scheduling policy) +tasks of the same nice level will be running for, or looking at it the other +way around, the longest duration two tasks of the same nice level will be +delayed for. When a task requests cpu time, it is given a quota (time_slice) +equal to the rr_interval and a virtual deadline. The virtual deadline is +offset from the current time in jiffies by this equation: + + jiffies + (prio_ratio * rr_interval) + +The prio_ratio is determined as a ratio compared to the baseline of nice -20 +and increases by 10% per nice level. The deadline is a virtual one only in that +no guarantee is placed that a task will actually be scheduled by this time, but +it is used to compare which task should go next. There are three components to +how a task is next chosen. First is time_slice expiration. If a task runs out +of its time_slice, it is descheduled, the time_slice is refilled, and the +deadline reset to that formula above. Second is sleep, where a task no longer +is requesting CPU for whatever reason. The time_slice and deadline are _not_ +adjusted in this case and are just carried over for when the task is next +scheduled. Third is preemption, and that is when a newly waking task is deemed +higher priority than a currently running task on any cpu by virtue of the fact +that it has an earlier virtual deadline than the currently running task. The +earlier deadline is the key to which task is next chosen for the first and +second cases. Once a task is descheduled, it is put back on the queue, and an +O(n) lookup of all queued-but-not-running tasks is done to determine which has +the earliest deadline and that task is chosen to receive CPU next. + +The CPU proportion of different nice tasks works out to be approximately the + + (prio_ratio difference)^2 + +The reason it is squared is that a task's deadline does not change while it is +running unless it runs out of time_slice. Thus, even if the time actually +passes the deadline of another task that is queued, it will not get CPU time +unless the current running task deschedules, and the time "base" (jiffies) is +constantly moving. + +Task lookup. + +BFS has 103 priority queues. 100 of these are dedicated to the static priority +of realtime tasks, and the remaining 3 are, in order of best to worst priority, +SCHED_ISO (isochronous), SCHED_NORMAL, and SCHED_IDLEPRIO (idle priority +scheduling). When a task of these priorities is queued, a bitmap of running +priorities is set showing which of these priorities has tasks waiting for CPU +time. When a CPU is made to reschedule, the lookup for the next task to get +CPU time is performed in the following way: + +First the bitmap is checked to see what static priority tasks are queued. If +any realtime priorities are found, the corresponding queue is checked and the +first task listed there is taken (provided CPU affinity is suitable) and lookup +is complete. If the priority corresponds to a SCHED_ISO task, they are also +taken in FIFO order (as they behave like SCHED_RR). If the priority corresponds +to either SCHED_NORMAL or SCHED_IDLEPRIO, then the lookup becomes O(n). At this +stage, every task in the runlist that corresponds to that priority is checked +to see which has the earliest set deadline, and (provided it has suitable CPU +affinity) it is taken off the runqueue and given the CPU. If a task has an +expired deadline, it is taken and the rest of the lookup aborted (as they are +chosen in FIFO order). + +Thus, the lookup is O(n) in the worst case only, where n is as described +earlier, as tasks may be chosen before the whole task list is looked over. + + +Scalability. + +The major limitations of BFS will be that of scalability, as the separate +runqueue designs will have less lock contention as the number of CPUs rises. +However they do not scale linearly even with separate runqueues as multiple +runqueues will need to be locked concurrently on such designs to be able to +achieve fair CPU balancing, to try and achieve some sort of nice-level fairness +across CPUs, and to achieve low enough latency for tasks on a busy CPU when +other CPUs would be more suited. BFS has the advantage that it requires no +balancing algorithm whatsoever, as balancing occurs by proxy simply because +all CPUs draw off the global runqueue, in priority and deadline order. Despite +the fact that scalability is _not_ the prime concern of BFS, it both shows very +good scalability to smaller numbers of CPUs and is likely a more scalable design +at these numbers of CPUs. + +It also has some very low overhead scalability features built into the design +when it has been deemed their overhead is so marginal that they're worth adding. +The first is the local copy of the running process' data to the CPU it's running +on to allow that data to be updated lockless where possible. Then there is +deference paid to the last CPU a task was running on, by trying that CPU first +when looking for an idle CPU to use the next time it's scheduled. Finally there +is the notion of cache locality beyond the last running CPU. The sched_domains +information is used to determine the relative virtual "cache distance" that +other CPUs have from the last CPU a task was running on. CPUs with shared +caches, such as SMT siblings, or multicore CPUs with shared caches, are treated +as cache local. CPUs without shared caches are treated as not cache local, and +CPUs on different NUMA nodes are treated as very distant. This "relative cache +distance" is used by modifying the virtual deadline value when doing lookups. +Effectively, the deadline is unaltered between "cache local" CPUs, doubled for +"cache distant" CPUs, and quadrupled for "very distant" CPUs. The reasoning +behind the doubling of deadlines is as follows. The real cost of migrating a +task from one CPU to another is entirely dependant on the cache footprint of +the task, how cache intensive the task is, how long it's been running on that +CPU to take up the bulk of its cache, how big the CPU cache is, how fast and +how layered the CPU cache is, how fast a context switch is... and so on. In +other words, it's close to random in the real world where we do more than just +one sole workload. The only thing we can be sure of is that it's not free. So +BFS uses the principle that an idle CPU is a wasted CPU and utilising idle CPUs +is more important than cache locality, and cache locality only plays a part +after that. Doubling the effective deadline is based on the premise that the +"cache local" CPUs will tend to work on the same tasks up to double the number +of cache local CPUs, and once the workload is beyond that amount, it is likely +that none of the tasks are cache warm anywhere anyway. The quadrupling for NUMA +is a value I pulled out of my arse. + +When choosing an idle CPU for a waking task, the cache locality is determined +according to where the task last ran and then idle CPUs are ranked from best +to worst to choose the most suitable idle CPU based on cache locality, NUMA +node locality and hyperthread sibling business. They are chosen in the +following preference (if idle): + +* Same core, idle or busy cache, idle threads +* Other core, same cache, idle or busy cache, idle threads. +* Same node, other CPU, idle cache, idle threads. +* Same node, other CPU, busy cache, idle threads. +* Same core, busy threads. +* Other core, same cache, busy threads. +* Same node, other CPU, busy threads. +* Other node, other CPU, idle cache, idle threads. +* Other node, other CPU, busy cache, idle threads. +* Other node, other CPU, busy threads. + +This shows the SMT or "hyperthread" awareness in the design as well which will +choose a real idle core first before a logical SMT sibling which already has +tasks on the physical CPU. + +Early benchmarking of BFS suggested scalability dropped off at the 16 CPU mark. +However this benchmarking was performed on an earlier design that was far less +scalable than the current one so it's hard to know how scalable it is in terms +of both CPUs (due to the global runqueue) and heavily loaded machines (due to +O(n) lookup) at this stage. Note that in terms of scalability, the number of +_logical_ CPUs matters, not the number of _physical_ CPUs. Thus, a dual (2x) +quad core (4X) hyperthreaded (2X) machine is effectively a 16X. Newer benchmark +results are very promising indeed, without needing to tweak any knobs, features +or options. Benchmark contributions are most welcome. + + +Features + +As the initial prime target audience for BFS was the average desktop user, it +was designed to not need tweaking, tuning or have features set to obtain benefit +from it. Thus the number of knobs and features has been kept to an absolute +minimum and should not require extra user input for the vast majority of cases. +There are precisely 2 tunables, and 2 extra scheduling policies. The rr_interval +and iso_cpu tunables, and the SCHED_ISO and SCHED_IDLEPRIO policies. In addition +to this, BFS also uses sub-tick accounting. What BFS does _not_ now feature is +support for CGROUPS. The average user should neither need to know what these +are, nor should they need to be using them to have good desktop behaviour. + +rr_interval + +There is only one "scheduler" tunable, the round robin interval. This can be +accessed in + + /proc/sys/kernel/rr_interval + +The value is in milliseconds, and the default value is set to 6 on a +uniprocessor machine, and automatically set to a progressively higher value on +multiprocessor machines. The reasoning behind increasing the value on more CPUs +is that the effective latency is decreased by virtue of there being more CPUs on +BFS (for reasons explained above), and increasing the value allows for less +cache contention and more throughput. Valid values are from 1 to 1000 +Decreasing the value will decrease latencies at the cost of decreasing +throughput, while increasing it will improve throughput, but at the cost of +worsening latencies. The accuracy of the rr interval is limited by HZ resolution +of the kernel configuration. Thus, the worst case latencies are usually slightly +higher than this actual value. The default value of 6 is not an arbitrary one. +It is based on the fact that humans can detect jitter at approximately 7ms, so +aiming for much lower latencies is pointless under most circumstances. It is +worth noting this fact when comparing the latency performance of BFS to other +schedulers. Worst case latencies being higher than 7ms are far worse than +average latencies not being in the microsecond range. + +Isochronous scheduling. + +Isochronous scheduling is a unique scheduling policy designed to provide +near-real-time performance to unprivileged (ie non-root) users without the +ability to starve the machine indefinitely. Isochronous tasks (which means +"same time") are set using, for example, the schedtool application like so: + + schedtool -I -e amarok + +This will start the audio application "amarok" as SCHED_ISO. How SCHED_ISO works +is that it has a priority level between true realtime tasks and SCHED_NORMAL +which would allow them to preempt all normal tasks, in a SCHED_RR fashion (ie, +if multiple SCHED_ISO tasks are running, they purely round robin at rr_interval +rate). However if ISO tasks run for more than a tunable finite amount of time, +they are then demoted back to SCHED_NORMAL scheduling. This finite amount of +time is the percentage of _total CPU_ available across the machine, configurable +as a percentage in the following "resource handling" tunable (as opposed to a +scheduler tunable): + + /proc/sys/kernel/iso_cpu + +and is set to 70% by default. It is calculated over a rolling 5 second average +Because it is the total CPU available, it means that on a multi CPU machine, it +is possible to have an ISO task running as realtime scheduling indefinitely on +just one CPU, as the other CPUs will be available. Setting this to 100 is the +equivalent of giving all users SCHED_RR access and setting it to 0 removes the +ability to run any pseudo-realtime tasks. + +A feature of BFS is that it detects when an application tries to obtain a +realtime policy (SCHED_RR or SCHED_FIFO) and the caller does not have the +appropriate privileges to use those policies. When it detects this, it will +give the task SCHED_ISO policy instead. Thus it is transparent to the user. +Because some applications constantly set their policy as well as their nice +level, there is potential for them to undo the override specified by the user +on the command line of setting the policy to SCHED_ISO. To counter this, once +a task has been set to SCHED_ISO policy, it needs superuser privileges to set +it back to SCHED_NORMAL. This will ensure the task remains ISO and all child +processes and threads will also inherit the ISO policy. + +Idleprio scheduling. + +Idleprio scheduling is a scheduling policy designed to give out CPU to a task +_only_ when the CPU would be otherwise idle. The idea behind this is to allow +ultra low priority tasks to be run in the background that have virtually no +effect on the foreground tasks. This is ideally suited to distributed computing +clients (like setiathome, folding, mprime etc) but can also be used to start +a video encode or so on without any slowdown of other tasks. To avoid this +policy from grabbing shared resources and holding them indefinitely, if it +detects a state where the task is waiting on I/O, the machine is about to +suspend to ram and so on, it will transiently schedule them as SCHED_NORMAL. As +per the Isochronous task management, once a task has been scheduled as IDLEPRIO, +it cannot be put back to SCHED_NORMAL without superuser privileges. Tasks can +be set to start as SCHED_IDLEPRIO with the schedtool command like so: + + schedtool -D -e ./mprime + +Subtick accounting. + +It is surprisingly difficult to get accurate CPU accounting, and in many cases, +the accounting is done by simply determining what is happening at the precise +moment a timer tick fires off. This becomes increasingly inaccurate as the +timer tick frequency (HZ) is lowered. It is possible to create an application +which uses almost 100% CPU, yet by being descheduled at the right time, records +zero CPU usage. While the main problem with this is that there are possible +security implications, it is also difficult to determine how much CPU a task +really does use. BFS tries to use the sub-tick accounting from the TSC clock, +where possible, to determine real CPU usage. This is not entirely reliable, but +is far more likely to produce accurate CPU usage data than the existing designs +and will not show tasks as consuming no CPU usage when they actually are. Thus, +the amount of CPU reported as being used by BFS will more accurately represent +how much CPU the task itself is using (as is shown for example by the 'time' +application), so the reported values may be quite different to other schedulers. +Values reported as the 'load' are more prone to problems with this design, but +per process values are closer to real usage. When comparing throughput of BFS +to other designs, it is important to compare the actual completed work in terms +of total wall clock time taken and total work done, rather than the reported +"cpu usage". + + +Con Kolivas Fri Aug 27 2010 diff --git b/Documentation/scheduler/sched-MuQSS.txt b/Documentation/scheduler/sched-MuQSS.txt new file mode 100644 index 0000000..7c18444 --- /dev/null +++ b/Documentation/scheduler/sched-MuQSS.txt @@ -0,0 +1,347 @@ +MuQSS - The Multiple Queue Skiplist Scheduler by Con Kolivas. + +MuQSS is a per-cpu runqueue variant of the original BFS scheduler with +one 8 level skiplist per runqueue, and fine grained locking for much more +scalability. + + +Goals. + +The goal of the Multiple Queue Skiplist Scheduler, referred to as MuQSS from +here on (pronounced mux) is to completely do away with the complex designs of +the past for the cpu process scheduler and instead implement one that is very +simple in basic design. The main focus of MuQSS is to achieve excellent desktop +interactivity and responsiveness without heuristics and tuning knobs that are +difficult to understand, impossible to model and predict the effect of, and when +tuned to one workload cause massive detriment to another, while still being +scalable to many CPUs and processes. + + +Design summary. + +MuQSS is best described as per-cpu multiple runqueue, O(log n) insertion, O(1) +lookup, earliest effective virtual deadline first tickless design, loosely based +on EEVDF (earliest eligible virtual deadline first) and my previous Staircase +Deadline scheduler, and evolved from the single runqueue O(n) BFS scheduler. +Each component shall be described in order to understand the significance of, +and reasoning for it. + + +Design reasoning. + +In BFS, the use of a single runqueue across all CPUs meant that each CPU would +need to scan the entire runqueue looking for the process with the earliest +deadline and schedule that next, regardless of which CPU it originally came +from. This made BFS deterministic with respect to latency and provided +guaranteed latencies dependent on number of processes and CPUs. The single +runqueue, however, meant that all CPUs would compete for the single lock +protecting it, which would lead to increasing lock contention as the number of +CPUs rose and appeared to limit scalability of common workloads beyond 16 +logical CPUs. Additionally, the O(n) lookup of the runqueue list obviously +increased overhead proportionate to the number of queued proecesses and led to +cache thrashing while iterating over the linked list. + +MuQSS is an evolution of BFS, designed to maintain the same scheduling +decision mechanism and be virtually deterministic without relying on the +constrained design of the single runqueue by splitting out the single runqueue +to be per-CPU and use skiplists instead of linked lists. + +The original reason for going back to a single runqueue design for BFS was that +once multiple runqueues are introduced, per-CPU or otherwise, there will be +complex interactions as each runqueue will be responsible for the scheduling +latency and fairness of the tasks only on its own runqueue, and to achieve +fairness and low latency across multiple CPUs, any advantage in throughput of +having CPU local tasks causes other disadvantages. This is due to requiring a +very complex balancing system to at best achieve some semblance of fairness +across CPUs and can only maintain relatively low latency for tasks bound to the +same CPUs, not across them. To increase said fairness and latency across CPUs, +the advantage of local runqueue locking, which makes for better scalability, is +lost due to having to grab multiple locks. + +MuQSS works around the problems inherent in multiple runqueue designs by +making its skip lists priority ordered and through novel use of lockless +examination of each other runqueue it can decide if it should take the earliest +deadline task from another runqueue for latency reasons, or for CPU balancing +reasons. It still does not have a balancing system, choosing to allow the +next task scheduling decision and task wakeup CPU choice to allow balancing to +happen by virtue of its choices. + + +Design details. + +Custom skip list implementation: + +To avoid the overhead of building up and tearing down skip list structures, +the variant used by MuQSS has a number of optimisations making it specific for +its use case in the scheduler. It uses static arrays of 8 'levels' instead of +building up and tearing down structures dynamically. This makes each runqueue +only scale O(log N) up to 64k tasks. However as there is one runqueue per CPU +it means that it scales O(log N) up to 64k x number of logical CPUs which is +far beyond the realistic task limits each CPU could handle. By being 8 levels +it also makes the array exactly one cacheline in size. Additionally, each +skip list node is bidirectional making insertion and removal amortised O(1), +being O(k) where k is 1-8. Uniquely, we are only ever interested in the very +first entry in each list at all times with MuQSS, so there is never a need to +do a search and thus look up is always O(1). In interactive mode, the queues +will be searched beyond their first entry if the first task is not suitable +for affinity or SMT nice reasons. + +Task insertion: + +MuQSS inserts tasks into a per CPU runqueue as an O(log N) insertion into +a custom skip list as described above (based on the original design by William +Pugh). Insertion is ordered in such a way that there is never a need to do a +search by ordering tasks according to static priority primarily, and then +virtual deadline at the time of insertion. + +Niffies: + +Niffies are a monotonic forward moving timer not unlike the "jiffies" but are +of nanosecond resolution. Niffies are calculated per-runqueue from the high +resolution TSC timers, and in order to maintain fairness are synchronised +between CPUs whenever both runqueues are locked concurrently. + +Virtual deadline: + +The key to achieving low latency, scheduling fairness, and "nice level" +distribution in MuQSS is entirely in the virtual deadline mechanism. The one +tunable in MuQSS is the rr_interval, or "round robin interval". This is the +maximum time two SCHED_OTHER (or SCHED_NORMAL, the common scheduling policy) +tasks of the same nice level will be running for, or looking at it the other +way around, the longest duration two tasks of the same nice level will be +delayed for. When a task requests cpu time, it is given a quota (time_slice) +equal to the rr_interval and a virtual deadline. The virtual deadline is +offset from the current time in niffies by this equation: + + niffies + (prio_ratio * rr_interval) + +The prio_ratio is determined as a ratio compared to the baseline of nice -20 +and increases by 10% per nice level. The deadline is a virtual one only in that +no guarantee is placed that a task will actually be scheduled by this time, but +it is used to compare which task should go next. There are three components to +how a task is next chosen. First is time_slice expiration. If a task runs out +of its time_slice, it is descheduled, the time_slice is refilled, and the +deadline reset to that formula above. Second is sleep, where a task no longer +is requesting CPU for whatever reason. The time_slice and deadline are _not_ +adjusted in this case and are just carried over for when the task is next +scheduled. Third is preemption, and that is when a newly waking task is deemed +higher priority than a currently running task on any cpu by virtue of the fact +that it has an earlier virtual deadline than the currently running task. The +earlier deadline is the key to which task is next chosen for the first and +second cases. + +The CPU proportion of different nice tasks works out to be approximately the + + (prio_ratio difference)^2 + +The reason it is squared is that a task's deadline does not change while it is +running unless it runs out of time_slice. Thus, even if the time actually +passes the deadline of another task that is queued, it will not get CPU time +unless the current running task deschedules, and the time "base" (niffies) is +constantly moving. + +Task lookup: + +As tasks are already pre-ordered according to anticipated scheduling order in +the skip lists, lookup for the next suitable task per-runqueue is always a +matter of simply selecting the first task in the 0th level skip list entry. +In order to maintain optimal latency and fairness across CPUs, MuQSS does a +novel examination of every other runqueue in cache locality order, choosing the +best task across all runqueues. This provides near-determinism of how long any +task across the entire system may wait before receiving CPU time. The other +runqueues are first examine lockless and then trylocked to minimise the +potential lock contention if they are likely to have a suitable better task. +Each other runqueue lock is only held for as long as it takes to examine the +entry for suitability. In "interactive" mode, the default setting, MuQSS will +look for the best deadline task across all CPUs, while in !interactive mode, +it will only select a better deadline task from another CPU if it is more +heavily laden than the current one. + +Lookup is therefore O(k) where k is number of CPUs. + + +Latency. + +Through the use of virtual deadlines to govern the scheduling order of normal +tasks, queue-to-activation latency per runqueue is guaranteed to be bound by +the rr_interval tunable which is set to 6ms by default. This means that the +longest a CPU bound task will wait for more CPU is proportional to the number +of running tasks and in the common case of 0-2 running tasks per CPU, will be +under the 7ms threshold for human perception of jitter. Additionally, as newly +woken tasks will have an early deadline from their previous runtime, the very +tasks that are usually latency sensitive will have the shortest interval for +activation, usually preempting any existing CPU bound tasks. + +Tickless expiry: + +A feature of MuQSS is that it is not tied to the resolution of the chosen tick +rate in Hz, instead depending entirely on the high resolution timers where +possible for sub-millisecond accuracy on timeouts regarless of the underlying +tick rate. This allows MuQSS to be run with the low overhead of low Hz rates +such as 100 by default, benefiting from the improved throughput and lower +power usage it provides. Another advantage of this approach is that in +combination with the Full No HZ option, which disables ticks on running task +CPUs instead of just idle CPUs, the tick can be disabled at all times +regardless of how many tasks are running instead of being limited to just one +running task. Note that this option is NOT recommended for regular desktop +users. + + +Scalability and balancing. + +Unlike traditional approaches where balancing is a combination of CPU selection +at task wakeup and intermittent balancing based on a vast array of rules set +according to architecture, busyness calculations and special case management, +MuQSS indirectly balances on the fly at task wakeup and next task selection. +During initialisation, MuQSS creates a cache coherency ordered list of CPUs for +each logical CPU and uses this to aid task/CPU selection when CPUs are busy. +Additionally it selects any idle CPUs, if they are available, at any time over +busy CPUs according to the following preference: + + * Same thread, idle or busy cache, idle or busy threads + * Other core, same cache, idle or busy cache, idle threads. + * Same node, other CPU, idle cache, idle threads. + * Same node, other CPU, busy cache, idle threads. + * Other core, same cache, busy threads. + * Same node, other CPU, busy threads. + * Other node, other CPU, idle cache, idle threads. + * Other node, other CPU, busy cache, idle threads. + * Other node, other CPU, busy threads. + +Mux is therefore SMT, MC and Numa aware without the need for extra +intermittent balancing to maintain CPUs busy and make the most of cache +coherency. + + +Features + +As the initial prime target audience for MuQSS was the average desktop user, it +was designed to not need tweaking, tuning or have features set to obtain benefit +from it. Thus the number of knobs and features has been kept to an absolute +minimum and should not require extra user input for the vast majority of cases. +There are 3 optional tunables, and 2 extra scheduling policies. The rr_interval, +interactive, and iso_cpu tunables, and the SCHED_ISO and SCHED_IDLEPRIO +policies. In addition to this, MuQSS also uses sub-tick accounting. What MuQSS +does _not_ now feature is support for CGROUPS. The average user should neither +need to know what these are, nor should they need to be using them to have good +desktop behaviour. However since some applications refuse to work without +cgroups, one can enable them with MuQSS as a stub and the filesystem will be +created which will allow the applications to work. + +rr_interval: + + /proc/sys/kernel/rr_interval + +The value is in milliseconds, and the default value is set to 6. Valid values +are from 1 to 1000 Decreasing the value will decrease latencies at the cost of +decreasing throughput, while increasing it will improve throughput, but at the +cost of worsening latencies. It is based on the fact that humans can detect +jitter at approximately 7ms, so aiming for much lower latencies is pointless +under most circumstances. It is worth noting this fact when comparing the +latency performance of MuQSS to other schedulers. Worst case latencies being +higher than 7ms are far worse than average latencies not being in the +microsecond range. + +interactive: + + /proc/sys/kernel/interactive + +The value is a simple boolean of 1 for on and 0 for off and is set to on by +default. Disabling this will disable the near-determinism of MuQSS when +selecting the next task by not examining all CPUs for the earliest deadline +task, or which CPU to wake to, instead prioritising CPU balancing for improved +throughput. Latency will still be bound by rr_interval, but on a per-CPU basis +instead of across the whole system. + +Isochronous scheduling: + +Isochronous scheduling is a unique scheduling policy designed to provide +near-real-time performance to unprivileged (ie non-root) users without the +ability to starve the machine indefinitely. Isochronous tasks (which means +"same time") are set using, for example, the schedtool application like so: + + schedtool -I -e amarok + +This will start the audio application "amarok" as SCHED_ISO. How SCHED_ISO works +is that it has a priority level between true realtime tasks and SCHED_NORMAL +which would allow them to preempt all normal tasks, in a SCHED_RR fashion (ie, +if multiple SCHED_ISO tasks are running, they purely round robin at rr_interval +rate). However if ISO tasks run for more than a tunable finite amount of time, +they are then demoted back to SCHED_NORMAL scheduling. This finite amount of +time is the percentage of CPU available per CPU, configurable as a percentage in +the following "resource handling" tunable (as opposed to a scheduler tunable): + +iso_cpu: + + /proc/sys/kernel/iso_cpu + +and is set to 70% by default. It is calculated over a rolling 5 second average +Because it is the total CPU available, it means that on a multi CPU machine, it +is possible to have an ISO task running as realtime scheduling indefinitely on +just one CPU, as the other CPUs will be available. Setting this to 100 is the +equivalent of giving all users SCHED_RR access and setting it to 0 removes the +ability to run any pseudo-realtime tasks. + +A feature of MuQSS is that it detects when an application tries to obtain a +realtime policy (SCHED_RR or SCHED_FIFO) and the caller does not have the +appropriate privileges to use those policies. When it detects this, it will +give the task SCHED_ISO policy instead. Thus it is transparent to the user. + + +Idleprio scheduling: + +Idleprio scheduling is a scheduling policy designed to give out CPU to a task +_only_ when the CPU would be otherwise idle. The idea behind this is to allow +ultra low priority tasks to be run in the background that have virtually no +effect on the foreground tasks. This is ideally suited to distributed computing +clients (like setiathome, folding, mprime etc) but can also be used to start a +video encode or so on without any slowdown of other tasks. To avoid this policy +from grabbing shared resources and holding them indefinitely, if it detects a +state where the task is waiting on I/O, the machine is about to suspend to ram +and so on, it will transiently schedule them as SCHED_NORMAL. Once a task has +been scheduled as IDLEPRIO, it cannot be put back to SCHED_NORMAL without +superuser privileges since it is effectively a lower scheduling policy. Tasks +can be set to start as SCHED_IDLEPRIO with the schedtool command like so: + +schedtool -D -e ./mprime + +Subtick accounting: + +It is surprisingly difficult to get accurate CPU accounting, and in many cases, +the accounting is done by simply determining what is happening at the precise +moment a timer tick fires off. This becomes increasingly inaccurate as the timer +tick frequency (HZ) is lowered. It is possible to create an application which +uses almost 100% CPU, yet by being descheduled at the right time, records zero +CPU usage. While the main problem with this is that there are possible security +implications, it is also difficult to determine how much CPU a task really does +use. Mux uses sub-tick accounting from the TSC clock to determine real CPU +usage. Thus, the amount of CPU reported as being used by MuQSS will more +accurately represent how much CPU the task itself is using (as is shown for +example by the 'time' application), so the reported values may be quite +different to other schedulers. When comparing throughput of MuQSS to other +designs, it is important to compare the actual completed work in terms of total +wall clock time taken and total work done, rather than the reported "cpu usage". + +Symmetric MultiThreading (SMT) aware nice: + +SMT, a.k.a. hyperthreading, is a very common feature on modern CPUs. While the +logical CPU count rises by adding thread units to each CPU core, allowing more +than one task to be run simultaneously on the same core, the disadvantage of it +is that the CPU power is shared between the tasks, not summating to the power +of two CPUs. The practical upshot of this is that two tasks running on +separate threads of the same core run significantly slower than if they had one +core each to run on. While smart CPU selection allows each task to have a core +to itself whenever available (as is done on MuQSS), it cannot offset the +slowdown that occurs when the cores are all loaded and only a thread is left. +Most of the time this is harmless as the CPU is effectively overloaded at this +point and the extra thread is of benefit. However when running a niced task in +the presence of an un-niced task (say nice 19 v nice 0), the nice task gets +precisely the same amount of CPU power as the unniced one. MuQSS has an +optional configuration feature known as SMT-NICE which selectively idles the +secondary niced thread for a period proportional to the nice difference, +allowing CPU distribution according to nice level to be maintained, at the +expense of a small amount of extra overhead. If this is configured in on a +machine without SMT threads, the overhead is minimal. + + +Con Kolivas Sat, 29th October 2016 diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index bac23c1..1d93520 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -39,6 +39,7 @@ show up in /proc/sys/kernel: - hung_task_timeout_secs - hung_task_warnings - kexec_load_disabled +- iso_cpu - kptr_restrict - l2cr [ PPC only ] - modprobe ==> Documentation/debugging-modules.txt @@ -72,6 +73,7 @@ show up in /proc/sys/kernel: - randomize_va_space - real-root-dev ==> Documentation/admin-guide/initrd.rst - reboot-cmd [ SPARC only ] +- rr_interval - rtsig-max - rtsig-nr - sem @@ -92,6 +94,7 @@ show up in /proc/sys/kernel: - unknown_nmi_panic - watchdog - watchdog_thresh +- yield_type - version ============================================================== @@ -394,6 +397,16 @@ When kptr_restrict is set to (2), kernel pointers printed using ============================================================== +iso_cpu: (MuQSS CPU scheduler only). + +This sets the percentage cpu that the unprivileged SCHED_ISO tasks can +run effectively at realtime priority, averaged over a rolling five +seconds over the -whole- system, meaning all cpus. + +Set to 70 (percent) by default. + +============================================================== + l2cr: (PPC only) This flag controls the L2 cache of G3 processor boards. If @@ -810,6 +823,20 @@ rebooting. ??? ============================================================== +rr_interval: (MuQSS CPU scheduler only) + +This is the smallest duration that any cpu process scheduling unit +will run for. Increasing this value can increase throughput of cpu +bound tasks substantially but at the expense of increased latencies +overall. Conversely decreasing it will decrease average and maximum +latencies but at the expense of throughput. This value is in +milliseconds and the default value chosen depends on the number of +cpus available at scheduler initialisation with a minimum of 6. + +Valid values are from 1-1000. + +============================================================== + rtsig-max & rtsig-nr: The file rtsig-max can be used to tune the maximum number @@ -1048,3 +1075,13 @@ The softlockup threshold is (2 * watchdog_thresh). Setting this tunable to zero will disable lockup detection altogether. ============================================================== + +yield_type: (MuQSS CPU scheduler only) + +This determines what type of yield calls to sched_yield will perform. + + 0: No yield. + 1: Yield only to better priority/deadline tasks. (default) + 2: Expire timeslice and recalculate deadline. + +============================================================== diff --git b/Documentation/tp_smapi.txt b/Documentation/tp_smapi.txt new file mode 100644 index 0000000..d037301 --- /dev/null +++ b/Documentation/tp_smapi.txt @@ -0,0 +1,267 @@ +tp_smapi version 0.40 +IBM ThinkPad hardware functions driver + +Author: Shem Multinymous +Project: http://sourceforge.net/projects/tpctl +Wiki: http://thinkwiki.org/wiki/tp_smapi +List: linux-thinkpad@linux-thinkpad.org + (http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad) + +Description +----------- + +ThinkPad laptops include a proprietary interface called SMAPI BIOS +(System Management Application Program Interface) which provides some +hardware control functionality that is not accessible by other means. + +This driver exposes some features of the SMAPI BIOS through a sysfs +interface. It is suitable for newer models, on which SMAPI is invoked +through IO port writes. Older models use a different SMAPI interface; +for those, try the "thinkpad" module from the "tpctl" package. + +WARNING: +This driver uses undocumented features and direct hardware access. +It thus cannot be guaranteed to work, and may cause arbitrary damage +(especially on models it wasn't tested on). + + +Module parameters +----------------- + +thinkpad_ec module: + force_io=1 lets thinkpad_ec load on some recent ThinkPad models + (e.g., T400 and T500) whose BIOS's ACPI DSDT reserves the ports we need. +tp_smapi module: + debug=1 enables verbose dmesg output. + + +Usage +----- + +Control of battery charging thresholds (in percents of current full charge +capacity): + +# echo 40 > /sys/devices/platform/smapi/BAT0/start_charge_thresh +# echo 70 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh +# cat /sys/devices/platform/smapi/BAT0/*_charge_thresh + + (This is useful since Li-Ion batteries wear out much faster at very + high or low charge levels. The driver will also keeps the thresholds + across suspend-to-disk with AC disconnected; this isn't done + automatically by the hardware.) + +Inhibiting battery charging for 17 minutes (overrides thresholds): + +# echo 17 > /sys/devices/platform/smapi/BAT0/inhibit_charge_minutes +# echo 0 > /sys/devices/platform/smapi/BAT0/inhibit_charge_minutes # stop +# cat /sys/devices/platform/smapi/BAT0/inhibit_charge_minutes + + (This can be used to control which battery is charged when using an + Ultrabay battery.) + +Forcing battery discharging even if AC power available: + +# echo 1 > /sys/devices/platform/smapi/BAT0/force_discharge # start discharge +# echo 0 > /sys/devices/platform/smapi/BAT0/force_discharge # stop discharge +# cat /sys/devices/platform/smapi/BAT0/force_discharge + + (When AC is connected, forced discharging will automatically stop + when battery is fully depleted -- this is useful for calibration. + Also, this attribute can be used to control which battery is discharged + when both a system battery and an Ultrabay battery are connected.) + +Misc read-only battery status attributes (see note about HDAPS below): + +/sys/devices/platform/smapi/BAT0/installed # 0 or 1 +/sys/devices/platform/smapi/BAT0/state # idle/charging/discharging +/sys/devices/platform/smapi/BAT0/cycle_count # integer counter +/sys/devices/platform/smapi/BAT0/current_now # instantaneous current +/sys/devices/platform/smapi/BAT0/current_avg # last minute average +/sys/devices/platform/smapi/BAT0/power_now # instantaneous power +/sys/devices/platform/smapi/BAT0/power_avg # last minute average +/sys/devices/platform/smapi/BAT0/last_full_capacity # in mWh +/sys/devices/platform/smapi/BAT0/remaining_percent # remaining percent of energy (set by calibration) +/sys/devices/platform/smapi/BAT0/remaining_percent_error # error range of remaing_percent (not reset by calibration) +/sys/devices/platform/smapi/BAT0/remaining_running_time # in minutes, by last minute average power +/sys/devices/platform/smapi/BAT0/remaining_running_time_now # in minutes, by instantenous power +/sys/devices/platform/smapi/BAT0/remaining_charging_time # in minutes +/sys/devices/platform/smapi/BAT0/remaining_capacity # in mWh +/sys/devices/platform/smapi/BAT0/design_capacity # in mWh +/sys/devices/platform/smapi/BAT0/voltage # in mV +/sys/devices/platform/smapi/BAT0/design_voltage # in mV +/sys/devices/platform/smapi/BAT0/charging_max_current # max charging current +/sys/devices/platform/smapi/BAT0/charging_max_voltage # max charging voltage +/sys/devices/platform/smapi/BAT0/group{0,1,2,3}_voltage # see below +/sys/devices/platform/smapi/BAT0/manufacturer # string +/sys/devices/platform/smapi/BAT0/model # string +/sys/devices/platform/smapi/BAT0/barcoding # string +/sys/devices/platform/smapi/BAT0/chemistry # string +/sys/devices/platform/smapi/BAT0/serial # integer +/sys/devices/platform/smapi/BAT0/manufacture_date # YYYY-MM-DD +/sys/devices/platform/smapi/BAT0/first_use_date # YYYY-MM-DD +/sys/devices/platform/smapi/BAT0/temperature # in milli-Celsius +/sys/devices/platform/smapi/BAT0/dump # see below +/sys/devices/platform/smapi/ac_connected # 0 or 1 + +The BAT0/group{0,1,2,3}_voltage attribute refers to the separate cell groups +in each battery. For example, on the ThinkPad 600, X3x, T4x and R5x models, +the battery contains 3 cell groups in series, where each group consisting of 2 +or 3 cells connected in parallel. The voltage of each group is given by these +attributes, and their sum (roughly) equals the "voltage" attribute. +(The effective performance of the battery is determined by the weakest group, +i.e., the one those voltage changes most rapidly during dis/charging.) + +The "BAT0/dump" attribute gives a a hex dump of the raw status data, which +contains additional data now in the above (if you can figure it out). Some +unused values are autodetected and replaced by "--": + +In all of the above, replace BAT0 with BAT1 to address the 2nd battery (e.g. +in the UltraBay). + + +Raw SMAPI calls: + +/sys/devices/platform/smapi/smapi_request +This performs raw SMAPI calls. It uses a bad interface that cannot handle +multiple simultaneous access. Don't touch it, it's for development only. +If you did touch it, you would so something like +# echo '211a 100 0 0' > /sys/devices/platform/smapi/smapi_request +# cat /sys/devices/platform/smapi/smapi_request +and notice that in the output "211a 34b b2 0 0 0 'OK'", the "4b" in the 2nd +value, converted to decimal is 75: the current charge stop threshold. + + +Model-specific status +--------------------- + +Works (at least partially) on the following ThinkPad model: +* A30 +* G41 +* R40, R50p, R51, R52 +* T23, T40, T40p, T41, T41p, T42, T42p, T43, T43p, T60 +* X24, X31, X32, X40, X41, X60 +* Z60t, Z61m + +Not all functions are available on all models; for detailed status, see: + http://thinkwiki.org/wiki/tp_smapi + +Please report success/failure by e-mail or on the Wiki. +If you get a "not implemented" or "not supported" message, your laptop +probably just can't do that (at least not via the SMAPI BIOS). +For negative reports, follow the bug reporting guidelines below. +If you send me the necessary technical data (i.e., SMAPI function +interfaces), I will support additional models. + + +Additional HDAPS features +------------------------- + +The modified hdaps driver has several improvements on the one in mainline +(beyond resolving the conflict with thinkpad_ec and tp_smapi): + +- Fixes reliability and improves support for recent ThinkPad models + (especially *60 and newer). Unlike the mainline driver, the modified hdaps + correctly follows the Embedded Controller communication protocol. + +- Extends the "invert" parameter to cover all possible axis orientations. + The possible values are as follows. + Let X,Y denote the hardware readouts. + Let R denote the laptop's roll (tilt left/right). + Let P denote the laptop's pitch (tilt forward/backward). + invert=0: R= X P= Y (same as mainline) + invert=1: R=-X P=-Y (same as mainline) + invert=2: R=-X P= Y (new) + invert=3: R= X P=-Y (new) + invert=4: R= Y P= X (new) + invert=5: R=-Y P=-X (new) + invert=6: R=-Y P= X (new) + invert=7: R= Y P=-X (new) + It's probably easiest to just try all 8 possibilities and see which yields + correct results (e.g., in the hdaps-gl visualisation). + +- Adds a whitelist which automatically sets the correct axis orientation for + some models. If the value for your model is wrong or missing, you can override + it using the "invert" parameter. Please also update the tables at + http://www.thinkwiki.org/wiki/tp_smapi and + http://www.thinkwiki.org/wiki/List_of_DMI_IDs + and submit a patch for the whitelist in hdaps.c. + +- Provides new attributes: + /sys/devices/platform/hdaps/sampling_rate: + This determines the frequency at which the host queries the embedded + controller for accelerometer data (and informs the hdaps input devices). + Default=50. + /sys/devices/platform/hdaps/oversampling_ratio: + When set to X, the embedded controller is told to do physical accelerometer + measurements at a rate that is X times higher than the rate at which + the driver reads those measurements (i.e., X*sampling_rate). This + makes the readouts from the embedded controller more fresh, and is also + useful for the running average filter (see next). Default=5 + /sys/devices/platform/hdaps/running_avg_filter_order: + When set to X, reported readouts will be the average of the last X physical + accelerometer measurements. Current firmware allows 1<=X<=8. Setting to a + high value decreases readout fluctuations. The averaging is handled by the + embedded controller, so no CPU resources are used. Higher values make the + readouts smoother, since it averages out both sensor noise (good) and abrupt + changes (bad). Default=2. + +- Provides a second input device, which publishes the raw accelerometer + measurements (without the fuzzing needed for joystick emulation). This input + device can be matched by a udev rule such as the following (all on one line): + KERNEL=="event[0-9]*", ATTRS{phys}=="hdaps/input1", + ATTRS{modalias}=="input:b0019v1014p5054e4801-*", + SYMLINK+="input/hdaps/accelerometer-event + +A new version of the hdapsd userspace daemon, which uses the input device +interface instead of polling sysfs, is available seprately. Using this reduces +the total interrupts per second generated by hdaps+hdapsd (on tickless kernels) +to 50, down from a value that fluctuates between 50 and 100. Set the +sampling_rate sysfs attribute to a lower value to further reduce interrupts, +at the expense of response latency. + +Licensing note: all my changes to the HDAPS driver are licensed under the +GPL version 2 or, at your option and to the extent allowed by derivation from +prior works, any later version. My version of hdaps is derived work from the +mainline version, which at the time of writing is available only under +GPL version 2. + +Bug reporting +------------- + +Mail . Please include: +* Details about your model, +* Relevant "dmesg" output. Make sure thinkpad_ec and tp_smapi are loaded with + the "debug=1" parameter (e.g., use "make load HDAPS=1 DEBUG=1"). +* Output of "dmidecode | grep -C5 Product" +* Does the failed functionality works under Windows? + + +More about SMAPI +---------------- + +For hints about what may be possible via the SMAPI BIOS and how, see: + +* IBM Technical Reference Manual for the ThinkPad 770 + (http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=PFAN-3TUQQD) +* Exported symbols in PWRMGRIF.DLL or TPPWRW32.DLL (e.g., use "objdump -x"). +* drivers/char/mwave/smapi.c in the Linux kernel tree.* +* The "thinkpad" SMAPI module (http://tpctl.sourceforge.net). +* The SMAPI_* constants in tp_smapi.c. + +Note that in the above Technical Reference and in the "thinkpad" module, +SMAPI is invoked through a function call to some physical address. However, +the interface used by tp_smapi and the above mwave drive, and apparently +required by newer ThinkPad, is different: you set the parameters up in the +CPU's registers and write to ports 0xB2 (the APM control port) and 0x4F; this +triggers an SMI (System Management Interrupt), causing the CPU to enter +SMM (System Management Mode) and run the BIOS firmware; the results are +returned in the CPU's registers. It is not clear what is the relation between +the two variants of SMAPI, though the assignment of error codes seems to be +similar. + +In addition, the embedded controller on ThinkPad laptops has a non-standard +interface at IO ports 0x1600-0x161F (mapped to LCP channel 3 of the H8S chip). +The interface provides various system management services (currently known: +battery information and accelerometer readouts). For more information see the +thinkpad_ec module and the H8S hardware documentation: +http://documentation.renesas.com/eng/products/mpumcu/rej09b0300_2140bhm.pdf diff --git a/Documentation/vm/00-INDEX b/Documentation/vm/00-INDEX index 11d3d8d..5269998 100644 --- a/Documentation/vm/00-INDEX +++ b/Documentation/vm/00-INDEX @@ -20,6 +20,8 @@ idle_page_tracking.txt - description of the idle page tracking feature. ksm.txt - how to use the Kernel Samepage Merging feature. +uksm.txt + - Introduction to Ultra KSM numa - information about NUMA specific code in the Linux vm. numa_memory_policy.txt diff --git b/Documentation/vm/uksm.txt b/Documentation/vm/uksm.txt new file mode 100644 index 0000000..b7a110f --- /dev/null +++ b/Documentation/vm/uksm.txt @@ -0,0 +1,61 @@ +The Ultra Kernel Samepage Merging feature +---------------------------------------------- +/* + * Ultra KSM. Copyright (C) 2011-2012 Nai Xia + * + * This is an improvement upon KSM. Some basic data structures and routines + * are borrowed from ksm.c . + * + * Its new features: + * 1. Full system scan: + * It automatically scans all user processes' anonymous VMAs. Kernel-user + * interaction to submit a memory area to KSM is no longer needed. + * + * 2. Rich area detection: + * It automatically detects rich areas containing abundant duplicated + * pages based. Rich areas are given a full scan speed. Poor areas are + * sampled at a reasonable speed with very low CPU consumption. + * + * 3. Ultra Per-page scan speed improvement: + * A new hash algorithm is proposed. As a result, on a machine with + * Core(TM)2 Quad Q9300 CPU in 32-bit mode and 800MHZ DDR2 main memory, it + * can scan memory areas that does not contain duplicated pages at speed of + * 627MB/sec ~ 2445MB/sec and can merge duplicated areas at speed of + * 477MB/sec ~ 923MB/sec. + * + * 4. Thrashing area avoidance: + * Thrashing area(an VMA that has frequent Ksm page break-out) can be + * filtered out. My benchmark shows it's more efficient than KSM's per-page + * hash value based volatile page detection. + * + * + * 5. Misc changes upon KSM: + * * It has a fully x86-opitmized memcmp dedicated for 4-byte-aligned page + * comparison. It's much faster than default C version on x86. + * * rmap_item now has an struct *page member to loosely cache a + * address-->page mapping, which reduces too much time-costly + * follow_page(). + * * The VMA creation/exit procedures are hooked to let the Ultra KSM know. + * * try_to_merge_two_pages() now can revert a pte if it fails. No break_ + * ksm is needed for this case. + * + * 6. Full Zero Page consideration(contributed by Figo Zhang) + * Now uksmd consider full zero pages as special pages and merge them to an + * special unswappable uksm zero page. + */ + +ChangeLog: + +2012-05-05 The creation of this Doc +2012-05-08 UKSM 0.1.1.1 libc crash bug fix, api clean up, doc clean up. +2012-05-28 UKSM 0.1.1.2 bug fix release +2012-06-26 UKSM 0.1.2-beta1 first beta release for 0.1.2 +2012-07-2 UKSM 0.1.2-beta2 +2012-07-10 UKSM 0.1.2-beta3 +2012-07-26 UKSM 0.1.2 Fine grained speed control, more scan optimization. +2012-10-13 UKSM 0.1.2.1 Bug fixes. +2012-12-31 UKSM 0.1.2.2 Minor bug fixes. +2014-07-02 UKSM 0.1.2.3 Fix a " __this_cpu_read() in preemptible bug". +2015-04-22 UKSM 0.1.2.4 Fix a race condition that can sometimes trigger anonying warnings. +2016-09-10 UKSM 0.1.2.5 Fix a bug in dedup ratio calculation. +2017-02-26 UKSM 0.1.2.6 Fix a bug in hugetlbpage handling and a race bug with page migration. diff --git a/MAINTAINERS b/MAINTAINERS index 1c3feff..c709795 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2392,6 +2392,19 @@ F: include/linux/audit.h F: include/uapi/linux/audit.h F: kernel/audit* +AUFS (advanced multi layered unification filesystem) FILESYSTEM +M: "J. R. Okajima" +L: linux-unionfs@vger.kernel.org +L: aufs-users@lists.sourceforge.net (members only) +W: http://aufs.sourceforge.net +T: git://github.com/sfjro/aufs4-linux.git +S: Supported +F: Documentation/filesystems/aufs/ +F: Documentation/ABI/testing/debugfs-aufs +F: Documentation/ABI/testing/sysfs-aufs +F: fs/aufs/ +F: include/uapi/linux/aufs_type.h + AUXILIARY DISPLAY DRIVERS M: Miguel Ojeda Sandonis W: http://miguelojeda.es/auxdisplay.htm @@ -13392,6 +13405,13 @@ S: Maintained F: drivers/tc/ F: include/linux/tc.h +TUXONICE (ENHANCED HIBERNATION) +P: Nigel Cunningham +M: nigel@nigelcunningham.com.au +L: tuxonice-devel@lists.nigelcunningham.com.au +W: http://tuxonice.net +S: Maintained + TW5864 VIDEO4LINUX DRIVER M: Bluecherry Maintainers M: Anton Sviridenko diff --git a/Makefile b/Makefile index 218a88d..7de59e9 100644 --- a/Makefile +++ b/Makefile @@ -638,12 +638,16 @@ ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += $(call cc-option,-Oz,-Os) KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) else +ifdef CONFIG_CC_OPTIMIZE_HARDER +KBUILD_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,) +else ifdef CONFIG_PROFILE_ALL_BRANCHES KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) else KBUILD_CFLAGS += -O2 endif endif +endif KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \ $(call cc-disable-warning,maybe-uninitialized,)) diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index 1fbb5da..29a929e 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -64,11 +64,6 @@ static struct task_struct *spusched_task; static struct timer_list spusched_timer; static struct timer_list spuloadavg_timer; -/* - * Priority of a normal, non-rt, non-niced'd process (aka nice level 0). - */ -#define NORMAL_PRIO 120 - /* * Frequency of the spu scheduler tick. By default we do one SPU scheduler * tick for every 10 CPU scheduler ticks. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 323cb06..ac5e3ef 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -945,10 +945,26 @@ config SCHED_SMT depends on SMP ---help--- SMT scheduler support improves the CPU scheduler's decision making - when dealing with Intel Pentium 4 chips with HyperThreading at a + when dealing with Intel P4/Core 2 chips with HyperThreading at a cost of slightly increased overhead in some places. If unsure say N here. +config SMT_NICE + bool "SMT (Hyperthreading) aware nice priority and policy support" + depends on SCHED_MUQSS && SCHED_SMT + default y + ---help--- + Enabling Hyperthreading on Intel CPUs decreases the effectiveness + of the use of 'nice' levels and different scheduling policies + (e.g. realtime) due to sharing of CPU power between hyperthreads. + SMT nice support makes each logical CPU aware of what is running on + its hyperthread siblings, maintaining appropriate distribution of + CPU according to nice levels and scheduling policies at the expense + of slightly increased overhead. + + If unsure say Y here. + + config SCHED_MC def_bool y prompt "Multi-core scheduler support" diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 3ba5ff2..893ba15 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -115,6 +115,7 @@ config MPENTIUMM config MPENTIUM4 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/older Xeon" depends on X86_32 + select X86_P6_NOP ---help--- Select this for Intel Pentium 4 chips. This includes the Pentium 4, Pentium D, P4-based Celeron and Xeon, and @@ -147,9 +148,8 @@ config MPENTIUM4 -Paxville -Dempsey - config MK6 - bool "K6/K6-II/K6-III" + bool "AMD K6/K6-II/K6-III" depends on X86_32 ---help--- Select this for an AMD K6-family processor. Enables use of @@ -157,7 +157,7 @@ config MK6 flags to GCC. config MK7 - bool "Athlon/Duron/K7" + bool "AMD Athlon/Duron/K7" depends on X86_32 ---help--- Select this for an AMD Athlon K7-family processor. Enables use of @@ -165,12 +165,83 @@ config MK7 flags to GCC. config MK8 - bool "Opteron/Athlon64/Hammer/K8" + bool "AMD Opteron/Athlon64/Hammer/K8" ---help--- Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables use of some extended instructions, and passes appropriate optimization flags to GCC. +config MK8SSE3 + bool "AMD Opteron/Athlon64/Hammer/K8 with SSE3" + ---help--- + Select this for improved AMD Opteron or Athlon64 Hammer-family processors. + Enables use of some extended instructions, and passes appropriate + optimization flags to GCC. + +config MK10 + bool "AMD 61xx/7x50/PhenomX3/X4/II/K10" + ---help--- + Select this for an AMD 61xx Eight-Core Magny-Cours, Athlon X2 7x50, + Phenom X3/X4/II, Athlon II X2/X3/X4, or Turion II-family processor. + Enables use of some extended instructions, and passes appropriate + optimization flags to GCC. + +config MBARCELONA + bool "AMD Barcelona" + ---help--- + Select this for AMD Family 10h Barcelona processors. + + Enables -march=barcelona + +config MBOBCAT + bool "AMD Bobcat" + ---help--- + Select this for AMD Family 14h Bobcat processors. + + Enables -march=btver1 + +config MJAGUAR + bool "AMD Jaguar" + ---help--- + Select this for AMD Family 16h Jaguar processors. + + Enables -march=btver2 + +config MBULLDOZER + bool "AMD Bulldozer" + ---help--- + Select this for AMD Family 15h Bulldozer processors. + + Enables -march=bdver1 + +config MPILEDRIVER + bool "AMD Piledriver" + ---help--- + Select this for AMD Family 15h Piledriver processors. + + Enables -march=bdver2 + +config MSTEAMROLLER + bool "AMD Steamroller" + ---help--- + Select this for AMD Family 15h Steamroller processors. + + Enables -march=bdver3 + +config MEXCAVATOR + bool "AMD Excavator" + ---help--- + Select this for AMD Family 15h Excavator processors. + + Enables -march=bdver4 + +config MPCK + bool "AMD Zen" + ---help--- + Select this for AMD Family 17h Zen processors. + + Enables -march=znver1 + config MCRUSOE bool "Crusoe" depends on X86_32 @@ -252,6 +323,7 @@ config MVIAC7 config MPSC bool "Intel P4 / older Netburst based Xeon" + select X86_P6_NOP depends on X86_64 ---help--- Optimize for Intel Pentium 4, Pentium D and older Nocona/Dempsey @@ -261,8 +333,19 @@ config MPSC using the cpu family field in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one. +config MATOM + bool "Intel Atom" + select X86_P6_NOP + ---help--- + + Select this for the Intel Atom platform. Intel Atom CPUs have an + in-order pipelining architecture and thus can benefit from + accordingly optimized code. Use a recent GCC with specific Atom + support in order to fully benefit from selecting this option. + config MCORE2 - bool "Core 2/newer Xeon" + bool "Intel Core 2" + select X86_P6_NOP ---help--- Select this for Intel Core 2 and newer Core 2 Xeons (Xeon 51xx and @@ -270,14 +353,79 @@ config MCORE2 family in /proc/cpuinfo. Newer ones have 6 and older ones 15 (not a typo) -config MATOM - bool "Intel Atom" + Enables -march=core2 + +config MNEHALEM + bool "Intel Nehalem" + select X86_P6_NOP ---help--- - Select this for the Intel Atom platform. Intel Atom CPUs have an - in-order pipelining architecture and thus can benefit from - accordingly optimized code. Use a recent GCC with specific Atom - support in order to fully benefit from selecting this option. + Select this for 1st Gen Core processors in the Nehalem family. + + Enables -march=nehalem + +config MWESTMERE + bool "Intel Westmere" + select X86_P6_NOP + ---help--- + + Select this for the Intel Westmere formerly Nehalem-C family. + + Enables -march=westmere + +config MSILVERMONT + bool "Intel Silvermont" + select X86_P6_NOP + ---help--- + + Select this for the Intel Silvermont platform. + + Enables -march=silvermont + +config MSANDYBRIDGE + bool "Intel Sandy Bridge" + select X86_P6_NOP + ---help--- + + Select this for 2nd Gen Core processors in the Sandy Bridge family. + + Enables -march=sandybridge + +config MIVYBRIDGE + bool "Intel Ivy Bridge" + select X86_P6_NOP + ---help--- + + Select this for 3rd Gen Core processors in the Ivy Bridge family. + + Enables -march=ivybridge + +config MHASWELL + bool "Intel Haswell" + select X86_P6_NOP + ---help--- + + Select this for 4th Gen Core processors in the Haswell family. + + Enables -march=haswell + +config MBROADWELL + bool "Intel Broadwell" + select X86_P6_NOP + ---help--- + + Select this for 5th Gen Core processors in the Broadwell family. + + Enables -march=broadwell + +config MSKYLAKE + bool "Intel Skylake" + select X86_P6_NOP + ---help--- + + Select this for 6th Gen Core processors in the Skylake family. + + Enables -march=skylake config GENERIC_CPU bool "Generic-x86-64" @@ -286,6 +434,19 @@ config GENERIC_CPU Generic x86-64 CPU. Run equally well on all x86-64 CPUs. +config MNATIVE + bool "Native optimizations autodetected by GCC" + ---help--- + + GCC 4.2 and above support -march=native, which automatically detects + the optimum settings to use based on your processor. -march=native + also detects and applies additional settings beyond -march specific + to your CPU, (eg. -msse4). Unless you have a specific reason not to + (e.g. distcc cross-compiling), you should probably be using + -march=native rather than anything listed below. + + Enables -march=native + endchoice config X86_GENERIC @@ -310,7 +471,7 @@ config X86_INTERNODE_CACHE_SHIFT config X86_L1_CACHE_SHIFT int default "7" if MPENTIUM4 || MPSC - default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU + default "6" if MK7 || MK8 || MK8SSE3 || MK10 || MBARCELONA || MBOBCAT || MBULLDOZER || MPILEDRIVER || MSTEAMROLLER || MEXCAVATOR || MPCK || MJAGUAR || MPENTIUMM || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU default "4" if MELAN || M486 || MGEODEGX1 default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX @@ -341,45 +502,46 @@ config X86_ALIGNMENT_16 config X86_INTEL_USERCOPY def_bool y - depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON || MCORE2 + depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK8SSE3 || MK7 || MEFFICEON || MCORE2 || MK10 || MBARCELONA || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE config X86_USE_PPRO_CHECKSUM def_bool y - depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM + depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MK10 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MK8SSE3 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MATOM || MNATIVE config X86_USE_3DNOW def_bool y depends on (MCYRIXIII || MK7 || MGEODE_LX) && !UML -# -# P6_NOPs are a relatively minor optimization that require a family >= -# 6 processor, except that it is broken on certain VIA chips. -# Furthermore, AMD chips prefer a totally different sequence of NOPs -# (which work on all CPUs). In addition, it looks like Virtual PC -# does not understand them. -# -# As a result, disallow these if we're not compiling for X86_64 (these -# NOPs do work on all x86-64 capable chips); the list of processors in -# the right-hand clause are the cores that benefit from this optimization. -# config X86_P6_NOP - def_bool y - depends on X86_64 - depends on (MCORE2 || MPENTIUM4 || MPSC) + default n + bool "Support for P6_NOPs on Intel chips" + depends on (MCORE2 || MPENTIUM4 || MPSC || MATOM || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE) + ---help--- + P6_NOPs are a relatively minor optimization that require a family >= + 6 processor, except that it is broken on certain VIA chips. + Furthermore, AMD chips prefer a totally different sequence of NOPs + (which work on all CPUs). In addition, it looks like Virtual PC + does not understand them. + + As a result, disallow these if we're not compiling for X86_64 (these + NOPs do work on all x86-64 capable chips); the list of processors in + the right-hand clause are the cores that benefit from this optimization. + + Say Y if you have Intel CPU newer than Pentium Pro, N otherwise. config X86_TSC def_bool y - depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM) || X86_64 + depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MK8SSE3 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MNATIVE || MATOM) || X86_64 config X86_CMPXCHG64 def_bool y - depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM + depends on X86_PAE || X86_64 || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM || MNATIVE # this should be set for all -march=.. options where the compiler # generates cmov. config X86_CMOV def_bool y - depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX) + depends on (MK8 || MK8SSE3 || MK10 || MBARCELONA || MBOBCAT || MBULLDOZER || MPILEDRIVER || MSTEAMROLLER || MEXCAVATOR || MPCK || MJAGUAR || MK7 || MCORE2 || MNEHALEM || MWESTMERE || MSILVERMONT || MSANDYBRIDGE || MIVYBRIDGE || MHASWELL || MBROADWELL || MSKYLAKE || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MNATIVE || MATOM || MGEODE_LX) config X86_MINIMUM_CPU_FAMILY int diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 1e902f9..4021747 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -121,13 +121,40 @@ else KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) + cflags-$(CONFIG_MNATIVE) += $(call cc-option,-march=native) cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8) + cflags-$(CONFIG_MK8SSE3) += $(call cc-option,-march=k8-sse3,-mtune=k8) + cflags-$(CONFIG_MK10) += $(call cc-option,-march=amdfam10) + cflags-$(CONFIG_MBARCELONA) += $(call cc-option,-march=barcelona) + cflags-$(CONFIG_MBOBCAT) += $(call cc-option,-march=btver1) + cflags-$(CONFIG_MJAGUAR) += $(call cc-option,-march=btver2) + cflags-$(CONFIG_MBULLDOZER) += $(call cc-option,-march=bdver1) + cflags-$(CONFIG_MPILEDRIVER) += $(call cc-option,-march=bdver2) + cflags-$(CONFIG_MSTEAMROLLER) += $(call cc-option,-march=bdver3) + cflags-$(CONFIG_MEXCAVATOR) += $(call cc-option,-march=bdver4) + cflags-$(CONFIG_MPCK) += $(call cc-option,-march=znver1) cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona) cflags-$(CONFIG_MCORE2) += \ - $(call cc-option,-march=core2,$(call cc-option,-mtune=generic)) - cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \ - $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) + $(call cc-option,-march=core2,$(call cc-option,-mtune=core2)) + cflags-$(CONFIG_MNEHALEM) += \ + $(call cc-option,-march=nehalem,$(call cc-option,-mtune=nehalem)) + cflags-$(CONFIG_MWESTMERE) += \ + $(call cc-option,-march=westmere,$(call cc-option,-mtune=westmere)) + cflags-$(CONFIG_MSILVERMONT) += \ + $(call cc-option,-march=silvermont,$(call cc-option,-mtune=silvermont)) + cflags-$(CONFIG_MSANDYBRIDGE) += \ + $(call cc-option,-march=sandybridge,$(call cc-option,-mtune=sandybridge)) + cflags-$(CONFIG_MIVYBRIDGE) += \ + $(call cc-option,-march=ivybridge,$(call cc-option,-mtune=ivybridge)) + cflags-$(CONFIG_MHASWELL) += \ + $(call cc-option,-march=haswell,$(call cc-option,-mtune=haswell)) + cflags-$(CONFIG_MBROADWELL) += \ + $(call cc-option,-march=broadwell,$(call cc-option,-mtune=broadwell)) + cflags-$(CONFIG_MSKYLAKE) += \ + $(call cc-option,-march=skylake,$(call cc-option,-mtune=skylake)) + cflags-$(CONFIG_MATOM) += $(call cc-option,-march=bonnell) \ + $(call cc-option,-mtune=bonnell,$(call cc-option,-mtune=generic)) cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic) KBUILD_CFLAGS += $(cflags-y) diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu index f3717d3..84418cc 100644 --- a/arch/x86/Makefile_32.cpu +++ b/arch/x86/Makefile_32.cpu @@ -22,7 +22,18 @@ cflags-$(CONFIG_MK6) += -march=k6 # Please note, that patches that add -march=athlon-xp and friends are pointless. # They make zero difference whatsosever to performance at this time. cflags-$(CONFIG_MK7) += -march=athlon +cflags-$(CONFIG_MNATIVE) += $(call cc-option,-march=native) cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon) +cflags-$(CONFIG_MK8SSE3) += $(call cc-option,-march=k8-sse3,-march=athlon) +cflags-$(CONFIG_MK10) += $(call cc-option,-march=amdfam10,-march=athlon) +cflags-$(CONFIG_MBARCELONA) += $(call cc-option,-march=barcelona,-march=athlon) +cflags-$(CONFIG_MBOBCAT) += $(call cc-option,-march=btver1,-march=athlon) +cflags-$(CONFIG_MJAGUAR) += $(call cc-option,-march=btver2,-march=athlon) +cflags-$(CONFIG_MBULLDOZER) += $(call cc-option,-march=bdver1,-march=athlon) +cflags-$(CONFIG_MPILEDRIVER) += $(call cc-option,-march=bdver2,-march=athlon) +cflags-$(CONFIG_MSTEAMROLLER) += $(call cc-option,-march=bdver3,-march=athlon) +cflags-$(CONFIG_MEXCAVATOR) += $(call cc-option,-march=bdver4,-march=athlon) +cflags-$(CONFIG_MPCK) += $(call cc-option,-march=znver1,-march=athlon) cflags-$(CONFIG_MCRUSOE) += -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0 cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0 cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586) @@ -31,8 +42,16 @@ cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) -falign-fu cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686) cflags-$(CONFIG_MVIAC7) += -march=i686 cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2) -cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom,$(call cc-option,-march=core2,-march=i686)) \ - $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) +cflags-$(CONFIG_MNEHALEM) += -march=i686 $(call tune,nehalem) +cflags-$(CONFIG_MWESTMERE) += -march=i686 $(call tune,westmere) +cflags-$(CONFIG_MSILVERMONT) += -march=i686 $(call tune,silvermont) +cflags-$(CONFIG_MSANDYBRIDGE) += -march=i686 $(call tune,sandybridge) +cflags-$(CONFIG_MIVYBRIDGE) += -march=i686 $(call tune,ivybridge) +cflags-$(CONFIG_MHASWELL) += -march=i686 $(call tune,haswell) +cflags-$(CONFIG_MBROADWELL) += -march=i686 $(call tune,broadwell) +cflags-$(CONFIG_MSKYLAKE) += -march=i686 $(call tune,skylake) +cflags-$(CONFIG_MATOM) += $(call cc-option,-march=bonnell,$(call cc-option,-march=core2,-march=i686)) \ + $(call cc-option,-mtune=bonnell,$(call cc-option,-mtune=generic)) # AMD Elan support cflags-$(CONFIG_MELAN) += -march=i486 diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h index e3b7819..470307f 100644 --- a/arch/x86/include/asm/module.h +++ b/arch/x86/include/asm/module.h @@ -15,6 +15,24 @@ #define MODULE_PROC_FAMILY "586MMX " #elif defined CONFIG_MCORE2 #define MODULE_PROC_FAMILY "CORE2 " +#elif defined CONFIG_MNATIVE +#define MODULE_PROC_FAMILY "NATIVE " +#elif defined CONFIG_MNEHALEM +#define MODULE_PROC_FAMILY "NEHALEM " +#elif defined CONFIG_MWESTMERE +#define MODULE_PROC_FAMILY "WESTMERE " +#elif defined CONFIG_MSILVERMONT +#define MODULE_PROC_FAMILY "SILVERMONT " +#elif defined CONFIG_MSANDYBRIDGE +#define MODULE_PROC_FAMILY "SANDYBRIDGE " +#elif defined CONFIG_MIVYBRIDGE +#define MODULE_PROC_FAMILY "IVYBRIDGE " +#elif defined CONFIG_MHASWELL +#define MODULE_PROC_FAMILY "HASWELL " +#elif defined CONFIG_MBROADWELL +#define MODULE_PROC_FAMILY "BROADWELL " +#elif defined CONFIG_MSKYLAKE +#define MODULE_PROC_FAMILY "SKYLAKE " #elif defined CONFIG_MATOM #define MODULE_PROC_FAMILY "ATOM " #elif defined CONFIG_M686 @@ -33,6 +51,26 @@ #define MODULE_PROC_FAMILY "K7 " #elif defined CONFIG_MK8 #define MODULE_PROC_FAMILY "K8 " +#elif defined CONFIG_MK8SSE3 +#define MODULE_PROC_FAMILY "K8SSE3 " +#elif defined CONFIG_MK10 +#define MODULE_PROC_FAMILY "K10 " +#elif defined CONFIG_MBARCELONA +#define MODULE_PROC_FAMILY "BARCELONA " +#elif defined CONFIG_MBOBCAT +#define MODULE_PROC_FAMILY "BOBCAT " +#elif defined CONFIG_MBULLDOZER +#define MODULE_PROC_FAMILY "BULLDOZER " +#elif defined CONFIG_MPILEDRIVER +#define MODULE_PROC_FAMILY "PILEDRIVER " +#elif defined CONFIG_MSTEAMROLLER +#define MODULE_PROC_FAMILY "STEAMROLLER " +#elif defined CONFIG_MJAGUAR +#define MODULE_PROC_FAMILY "JAGUAR " +#elif defined CONFIG_MEXCAVATOR +#define MODULE_PROC_FAMILY "EXCAVATOR " +#elif defined CONFIG_MPCK +#define MODULE_PROC_FAMILY "PCK " #elif defined CONFIG_MELAN #define MODULE_PROC_FAMILY "ELAN " #elif defined CONFIG_MCRUSOE diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 3b9e220..8a08a5f 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -728,6 +728,16 @@ static void init_amd_bd(struct cpuinfo_x86 *c) } } +static void init_amd_zn(struct cpuinfo_x86 *c) +{ + /* + * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects + * all up to and including B1. + */ + if (c->x86_model <= 1 && c->x86_mask <= 1) + set_cpu_cap(c, X86_FEATURE_CPB); +} + static void init_amd(struct cpuinfo_x86 *c) { u32 dummy; @@ -758,6 +768,7 @@ static void init_amd(struct cpuinfo_x86 *c) case 0x10: init_amd_gh(c); break; case 0x12: init_amd_ln(c); break; case 0x15: init_amd_bd(c); break; + case 0x17: init_amd_zn(c); break; } /* Enable workaround for FXSAVE leak */ diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index 6b91e2e..e099c75 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -175,6 +175,7 @@ void init_espfix_ap(int cpu) struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0); pmd_p = (pmd_t *)page_address(page); + SetPageTOI_Untracked(virt_to_page(pmd_p)); pud = __pud(__pa(pmd_p) | (PGTABLE_PROT & ptemask)); paravirt_alloc_pmd(&init_mm, __pa(pmd_p) >> PAGE_SHIFT); for (n = 0; n < ESPFIX_PUD_CLONES; n++) @@ -187,6 +188,7 @@ void init_espfix_ap(int cpu) struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0); pte_p = (pte_t *)page_address(page); + SetPageTOI_Untracked(virt_to_page(pte_p)); pmd = __pmd(__pa(pte_p) | (PGTABLE_PROT & ptemask)); paravirt_alloc_pte(&init_mm, __pa(pte_p) >> PAGE_SHIFT); for (n = 0; n < ESPFIX_PMD_CLONES; n++) @@ -195,6 +197,7 @@ void init_espfix_ap(int cpu) pte_p = pte_offset_kernel(&pmd, addr); stack_page = page_address(alloc_pages_node(node, GFP_KERNEL, 0)); + SetPageTOI_Untracked(virt_to_page(stack_page)); pte = __pte(__pa(stack_page) | (__PAGE_KERNEL_RO & ptemask)); for (n = 0; n < ESPFIX_PTE_CLONES; n++) set_pte(&pte_p[n*PTE_STRIDE], pte); diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 796d96b..2f3f24e 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -120,6 +121,10 @@ static void cyc2ns_init(int cpu) cyc2ns_data_init(&c2n->data[1]); seqcount_init(&c2n->seq); + + // Don't let TuxOnIce make data RO - a secondary CPU will cause a triple fault + // if it loads microcode, which then does a printk, which may end up invoking cycles_2_ns + SetPageTOI_Untracked(virt_to_page(c2n)); } static inline unsigned long long cycles_2_ns(unsigned long long cyc) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 955be01..bf77d5b 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -14,6 +14,7 @@ #include /* hstate_index_to_shift */ #include /* prefetchw */ #include /* exception_enter(), ... */ +#include /* incremental image support */ #include /* faulthandler_disabled() */ #include /* boot_cpu_has, ... */ @@ -757,6 +758,10 @@ no_context(struct pt_regs *regs, unsigned long error_code, unsigned long flags; int sig; + if (toi_make_writable(init_mm.pgd, address)) { + return; + } + /* Are we prepared to handle this kernel fault? */ if (fixup_exception(regs, X86_TRAP_PF)) { /* @@ -1079,10 +1084,101 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code, } } +#ifdef CONFIG_TOI_INCREMENTAL +/** + * _toi_do_cbw - Do a copy-before-write before letting the faulting process continue + */ +static void toi_do_cbw(struct page *page) +{ + struct toi_cbw_state *state = this_cpu_ptr(&toi_cbw_states); + + state->active = 1; + wmb(); + + if (state->enabled && state->next && PageTOI_CBW(page)) { + struct toi_cbw *this = state->next; + memcpy(this->virt, page_address(page), PAGE_SIZE); + this->pfn = page_to_pfn(page); + state->next = this->next; + } + + state->active = 0; +} + +/** + * _toi_make_writable - Defuse TOI's write protection + */ +int _toi_make_writable(pte_t *pte) +{ + struct page *page = pte_page(*pte); + if (PageTOI_RO(page)) { + pgd_t *pgd = __va(read_cr3()); + /* + * If this is a TuxOnIce caused fault, we may not have permission to + * write to a page needed to reset the permissions of the original + * page. Use swapper_pg_dir to get around this. + */ + load_cr3(swapper_pg_dir); + + set_pte_atomic(pte, pte_mkwrite(*pte)); + SetPageTOI_Dirty(page); + ClearPageTOI_RO(page); + + toi_do_cbw(page); + + load_cr3(pgd); + return 1; + } + return 0; +} + +/** + * toi_make_writable - Handle a (potential) fault caused by TOI's write protection + * + * Make a page writable that was protected. Might be because of a fault, or + * because we're allocating it and want it to be untracked. + * + * Note that in the fault handling case, we don't care about the error code. If + * called from the double fault handler, we won't have one. We just check to + * see if the page was made RO by TOI, and mark it dirty/release the protection + * if it was. + */ +int toi_make_writable(pgd_t *pgd, unsigned long address) +{ + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd + pgd_index(address); + if (!pgd_present(*pgd)) + return 0; + + pud = pud_offset(pgd, address); + if (!pud_present(*pud)) + return 0; + + if (pud_large(*pud)) + return _toi_make_writable((pte_t *) pud); + + pmd = pmd_offset(pud, address); + if (!pmd_present(*pmd)) + return 0; + + if (pmd_large(*pmd)) + return _toi_make_writable((pte_t *) pmd); + + pte = pte_offset_kernel(pmd, address); + if (!pte_present(*pte)) + return 0; + + return _toi_make_writable(pte); +} +#endif + static int spurious_fault_check(unsigned long error_code, pte_t *pte) { if ((error_code & PF_WRITE) && !pte_write(*pte)) - return 0; + return 0; if ((error_code & PF_INSTR) && !pte_exec(*pte)) return 0; @@ -1280,6 +1376,15 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, kmemcheck_hide(regs); prefetchw(&mm->mmap_sem); + /* + * Detect and handle page faults due to TuxOnIce making pages read-only + * so that it can create incremental images. + * + * Do it early to avoid double faults. + */ + if (unlikely(toi_make_writable(init_mm.pgd, address))) + return; + if (unlikely(kmmio_fault(regs, address))) return; diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index bf3f106..988b086 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -163,8 +163,8 @@ static int page_size_mask; static void __init probe_page_size_mask(void) { /* - * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will - * use small pages. + * For CONFIG_KMEMCHECK, TuxOnIce's incremental image support or + * pagealloc debugging, identity mapping will use small pages. * This will simplify cpa(), which otherwise needs to support splitting * large pages into small in interrupt context, etc. */ diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched index fd2cefa..9defb30 100644 --- a/block/Kconfig.iosched +++ b/block/Kconfig.iosched @@ -39,6 +39,26 @@ config CFQ_GROUP_IOSCHED ---help--- Enable group IO scheduling in CFQ. +config IOSCHED_BFQ_SQ + tristate "BFQ-SQ I/O scheduler" + default n + ---help--- + The BFQ-SQ I/O scheduler (for legacy blk: SQ stands for + SingleQueue) distributes bandwidth among all processes + according to their weights, regardless of the device + parameters and with any workload. It also guarantees a low + latency to interactive and soft real-time applications. + Details in Documentation/block/bfq-iosched.txt + +config BFQ_SQ_GROUP_IOSCHED + bool "BFQ-SQ hierarchical scheduling support" + depends on IOSCHED_BFQ_SQ && BLK_CGROUP + default n + ---help--- + + Enable hierarchical scheduling in BFQ-SQ, using the blkio + (cgroups-v1) or io (cgroups-v2) controller. + choice prompt "Default I/O scheduler" @@ -53,6 +73,16 @@ choice config DEFAULT_CFQ bool "CFQ" if IOSCHED_CFQ=y + config DEFAULT_BFQ_SQ + bool "BFQ-SQ" if IOSCHED_BFQ_SQ=y + help + Selects BFQ-SQ as the default I/O scheduler which will be + used by default for all block devices. + The BFQ-SQ I/O scheduler aims at distributing the bandwidth + as desired, independently of the disk parameters and with + any workload. It also tries to guarantee low latency to + interactive and soft real-time applications. + config DEFAULT_NOOP bool "No-op" @@ -62,8 +92,28 @@ config DEFAULT_IOSCHED string default "deadline" if DEFAULT_DEADLINE default "cfq" if DEFAULT_CFQ + default "bfq-sq" if DEFAULT_BFQ_SQ default "noop" if DEFAULT_NOOP +config MQ_IOSCHED_BFQ + tristate "BFQ-MQ I/O Scheduler" + default y + ---help--- + BFQ I/O scheduler for BLK-MQ. BFQ-MQ distributes bandwidth + among all processes according to their weights, regardless of + the device parameters and with any workload. It also + guarantees a low latency to interactive and soft real-time + applications. Details in Documentation/block/bfq-iosched.txt + +config MQ_BFQ_GROUP_IOSCHED + bool "BFQ-MQ hierarchical scheduling support" + depends on MQ_IOSCHED_BFQ && BLK_CGROUP + default n + ---help--- + + Enable hierarchical scheduling in BFQ-MQ, using the blkio + (cgroups-v1) or io (cgroups-v2) controller. + config MQ_IOSCHED_DEADLINE tristate "MQ deadline I/O scheduler" default y diff --git a/block/Makefile b/block/Makefile index 2b281cf..4802f2a 100644 --- a/block/Makefile +++ b/block/Makefile @@ -6,7 +6,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \ blk-flush.o blk-settings.o blk-ioc.o blk-map.o \ blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \ blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \ - blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \ + blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o uuid.o \ genhd.o partition-generic.o ioprio.o \ badblocks.o partitions/ @@ -23,6 +23,8 @@ obj-$(CONFIG_MQ_IOSCHED_DEADLINE) += mq-deadline.o obj-$(CONFIG_MQ_IOSCHED_KYBER) += kyber-iosched.o bfq-y := bfq-iosched.o bfq-wf2q.o bfq-cgroup.o obj-$(CONFIG_IOSCHED_BFQ) += bfq.o +obj-$(CONFIG_IOSCHED_BFQ_SQ) += bfq-sq-iosched.o +obj-$(CONFIG_MQ_IOSCHED_BFQ) += bfq-mq-iosched.o obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o obj-$(CONFIG_BLK_CMDLINE_PARSER) += cmdline-parser.o diff --git b/block/bfq-cgroup-included.c b/block/bfq-cgroup-included.c new file mode 100644 index 0000000..631e53d --- /dev/null +++ b/block/bfq-cgroup-included.c @@ -0,0 +1,1329 @@ +/* + * BFQ: CGROUPS support. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2016 Paolo Valente + * + * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ + * file. + */ + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + +/* bfqg stats flags */ +enum bfqg_stats_flags { + BFQG_stats_waiting = 0, + BFQG_stats_idling, + BFQG_stats_empty, +}; + +#define BFQG_FLAG_FNS(name) \ +static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \ +{ \ + stats->flags |= (1 << BFQG_stats_##name); \ +} \ +static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \ +{ \ + stats->flags &= ~(1 << BFQG_stats_##name); \ +} \ +static int bfqg_stats_##name(struct bfqg_stats *stats) \ +{ \ + return (stats->flags & (1 << BFQG_stats_##name)) != 0; \ +} \ + +BFQG_FLAG_FNS(waiting) +BFQG_FLAG_FNS(idling) +BFQG_FLAG_FNS(empty) +#undef BFQG_FLAG_FNS + +#ifdef BFQ_MQ +/* This should be called with the scheduler lock held. */ +#else +/* This should be called with the queue_lock held. */ +#endif +static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats) +{ + unsigned long long now; + + if (!bfqg_stats_waiting(stats)) + return; + + now = sched_clock(); + if (time_after64(now, stats->start_group_wait_time)) + blkg_stat_add(&stats->group_wait_time, + now - stats->start_group_wait_time); + bfqg_stats_clear_waiting(stats); +} + +#ifdef BFQ_MQ +/* This should be called with the scheduler lock held. */ +#else +/* This should be called with the queue_lock held. */ +#endif +static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, + struct bfq_group *curr_bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + if (bfqg_stats_waiting(stats)) + return; + if (bfqg == curr_bfqg) + return; + stats->start_group_wait_time = sched_clock(); + bfqg_stats_mark_waiting(stats); +} + +#ifdef BFQ_MQ +/* This should be called with the scheduler lock held. */ +#else +/* This should be called with the queue_lock held. */ +#endif +static void bfqg_stats_end_empty_time(struct bfqg_stats *stats) +{ + unsigned long long now; + + if (!bfqg_stats_empty(stats)) + return; + + now = sched_clock(); + if (time_after64(now, stats->start_empty_time)) + blkg_stat_add(&stats->empty_time, + now - stats->start_empty_time); + bfqg_stats_clear_empty(stats); +} + +static void bfqg_stats_update_dequeue(struct bfq_group *bfqg) +{ + blkg_stat_add(&bfqg->stats.dequeue, 1); +} + +static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + if (blkg_rwstat_total(&stats->queued)) + return; + + /* + * group is already marked empty. This can happen if bfqq got new + * request in parent group and moved to this group while being added + * to service tree. Just ignore the event and move on. + */ + if (bfqg_stats_empty(stats)) + return; + + stats->start_empty_time = sched_clock(); + bfqg_stats_mark_empty(stats); +} + +static void bfqg_stats_update_idle_time(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + if (bfqg_stats_idling(stats)) { + unsigned long long now = sched_clock(); + + if (time_after64(now, stats->start_idle_time)) + blkg_stat_add(&stats->idle_time, + now - stats->start_idle_time); + bfqg_stats_clear_idling(stats); + } +} + +static void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + stats->start_idle_time = sched_clock(); + bfqg_stats_mark_idling(stats); +} + +static void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + blkg_stat_add(&stats->avg_queue_size_sum, + blkg_rwstat_total(&stats->queued)); + blkg_stat_add(&stats->avg_queue_size_samples, 1); + bfqg_stats_update_group_wait_time(stats); +} + +static struct blkcg_policy blkcg_policy_bfq; + +/* + * blk-cgroup policy-related handlers + * The following functions help in converting between blk-cgroup + * internal structures and BFQ-specific structures. + */ + +static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd) +{ + return pd ? container_of(pd, struct bfq_group, pd) : NULL; +} + +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg) +{ + return pd_to_blkg(&bfqg->pd); +} + +static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg) +{ + struct blkg_policy_data *pd = blkg_to_pd(blkg, &blkcg_policy_bfq); + + return pd_to_bfqg(pd); +} + +/* + * bfq_group handlers + * The following functions help in navigating the bfq_group hierarchy + * by allowing to find the parent of a bfq_group or the bfq_group + * associated to a bfq_queue. + */ + +static struct bfq_group *bfqg_parent(struct bfq_group *bfqg) +{ + struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent; + + return pblkg ? blkg_to_bfqg(pblkg) : NULL; +} + +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq) +{ + struct bfq_entity *group_entity = bfqq->entity.parent; + + return group_entity ? container_of(group_entity, struct bfq_group, + entity) : + bfqq->bfqd->root_group; +} + +/* + * The following two functions handle get and put of a bfq_group by + * wrapping the related blk-cgroup hooks. + */ + +static void bfqg_get(struct bfq_group *bfqg) +{ +#ifdef BFQ_MQ + bfqg->ref++; +#else + blkg_get(bfqg_to_blkg(bfqg)); +#endif +} + +static void bfqg_put(struct bfq_group *bfqg) +{ +#ifdef BFQ_MQ + bfqg->ref--; + + BUG_ON(bfqg->ref < 0); + if (bfqg->ref == 0) + kfree(bfqg); +#else + blkg_put(bfqg_to_blkg(bfqg)); +#endif +} + +#ifdef BFQ_MQ +static void bfqg_and_blkg_get(struct bfq_group *bfqg) +{ + /* see comments in bfq_bic_update_cgroup for why refcounting bfqg */ + bfqg_get(bfqg); + + blkg_get(bfqg_to_blkg(bfqg)); +} + +static void bfqg_and_blkg_put(struct bfq_group *bfqg) +{ + bfqg_put(bfqg); + + blkg_put(bfqg_to_blkg(bfqg)); +} +#endif + +static void bfqg_stats_update_io_add(struct bfq_group *bfqg, + struct bfq_queue *bfqq, + unsigned int op) +{ + blkg_rwstat_add(&bfqg->stats.queued, op, 1); + bfqg_stats_end_empty_time(&bfqg->stats); + if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue)) + bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq)); +} + +static void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op) +{ + blkg_rwstat_add(&bfqg->stats.queued, op, -1); +} + +static void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) +{ + blkg_rwstat_add(&bfqg->stats.merged, op, 1); +} + +static void bfqg_stats_update_completion(struct bfq_group *bfqg, + uint64_t start_time, uint64_t io_start_time, + unsigned int op) +{ + struct bfqg_stats *stats = &bfqg->stats; + unsigned long long now = sched_clock(); + + if (time_after64(now, io_start_time)) + blkg_rwstat_add(&stats->service_time, op, + now - io_start_time); + if (time_after64(io_start_time, start_time)) + blkg_rwstat_add(&stats->wait_time, op, + io_start_time - start_time); +} + +/* @stats = 0 */ +static void bfqg_stats_reset(struct bfqg_stats *stats) +{ + /* queued stats shouldn't be cleared */ + blkg_rwstat_reset(&stats->merged); + blkg_rwstat_reset(&stats->service_time); + blkg_rwstat_reset(&stats->wait_time); + blkg_stat_reset(&stats->time); + blkg_stat_reset(&stats->avg_queue_size_sum); + blkg_stat_reset(&stats->avg_queue_size_samples); + blkg_stat_reset(&stats->dequeue); + blkg_stat_reset(&stats->group_wait_time); + blkg_stat_reset(&stats->idle_time); + blkg_stat_reset(&stats->empty_time); +} + +/* @to += @from */ +static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from) +{ + if (!to || !from) + return; + + /* queued stats shouldn't be cleared */ + blkg_rwstat_add_aux(&to->merged, &from->merged); + blkg_rwstat_add_aux(&to->service_time, &from->service_time); + blkg_rwstat_add_aux(&to->wait_time, &from->wait_time); + blkg_stat_add_aux(&from->time, &from->time); + blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum); + blkg_stat_add_aux(&to->avg_queue_size_samples, + &from->avg_queue_size_samples); + blkg_stat_add_aux(&to->dequeue, &from->dequeue); + blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time); + blkg_stat_add_aux(&to->idle_time, &from->idle_time); + blkg_stat_add_aux(&to->empty_time, &from->empty_time); +} + +/* + * Transfer @bfqg's stats to its parent's dead_stats so that the ancestors' + * recursive stats can still account for the amount used by this bfqg after + * it's gone. + */ +static void bfqg_stats_xfer_dead(struct bfq_group *bfqg) +{ + struct bfq_group *parent; + + if (!bfqg) /* root_group */ + return; + + parent = bfqg_parent(bfqg); + + lockdep_assert_held(bfqg_to_blkg(bfqg)->q->queue_lock); + + if (unlikely(!parent)) + return; + + bfqg_stats_add_aux(&parent->stats, &bfqg->stats); + bfqg_stats_reset(&bfqg->stats); +} + +static void bfq_init_entity(struct bfq_entity *entity, + struct bfq_group *bfqg) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + entity->weight = entity->new_weight; + entity->orig_weight = entity->new_weight; + if (bfqq) { + bfqq->ioprio = bfqq->new_ioprio; + bfqq->ioprio_class = bfqq->new_ioprio_class; +#ifdef BFQ_MQ + /* + * Make sure that bfqg and its associated blkg do not + * disappear before entity. + */ + bfqg_and_blkg_get(bfqg); +#else + bfqg_get(bfqg); +#endif + } + entity->parent = bfqg->my_entity; /* NULL for root group */ + entity->sched_data = &bfqg->sched_data; +} + +static void bfqg_stats_exit(struct bfqg_stats *stats) +{ + blkg_rwstat_exit(&stats->merged); + blkg_rwstat_exit(&stats->service_time); + blkg_rwstat_exit(&stats->wait_time); + blkg_rwstat_exit(&stats->queued); + blkg_stat_exit(&stats->time); + blkg_stat_exit(&stats->avg_queue_size_sum); + blkg_stat_exit(&stats->avg_queue_size_samples); + blkg_stat_exit(&stats->dequeue); + blkg_stat_exit(&stats->group_wait_time); + blkg_stat_exit(&stats->idle_time); + blkg_stat_exit(&stats->empty_time); +} + +static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp) +{ + if (blkg_rwstat_init(&stats->merged, gfp) || + blkg_rwstat_init(&stats->service_time, gfp) || + blkg_rwstat_init(&stats->wait_time, gfp) || + blkg_rwstat_init(&stats->queued, gfp) || + blkg_stat_init(&stats->time, gfp) || + blkg_stat_init(&stats->avg_queue_size_sum, gfp) || + blkg_stat_init(&stats->avg_queue_size_samples, gfp) || + blkg_stat_init(&stats->dequeue, gfp) || + blkg_stat_init(&stats->group_wait_time, gfp) || + blkg_stat_init(&stats->idle_time, gfp) || + blkg_stat_init(&stats->empty_time, gfp)) { + bfqg_stats_exit(stats); + return -ENOMEM; + } + + return 0; +} + +static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd) +{ + return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL; +} + +static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg) +{ + return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq)); +} + +static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp) +{ + struct bfq_group_data *bgd; + + bgd = kzalloc(sizeof(*bgd), gfp); + if (!bgd) + return NULL; + return &bgd->pd; +} + +static void bfq_cpd_init(struct blkcg_policy_data *cpd) +{ + struct bfq_group_data *d = cpd_to_bfqgd(cpd); + + d->weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ? + CGROUP_WEIGHT_DFL : BFQ_WEIGHT_LEGACY_DFL; +} + +static void bfq_cpd_free(struct blkcg_policy_data *cpd) +{ + kfree(cpd_to_bfqgd(cpd)); +} + +static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, int node) +{ + struct bfq_group *bfqg; + + bfqg = kzalloc_node(sizeof(*bfqg), gfp, node); + if (!bfqg) + return NULL; + + if (bfqg_stats_init(&bfqg->stats, gfp)) { + kfree(bfqg); + return NULL; + } + +#ifdef BFQ_MQ + /* see comments in bfq_bic_update_cgroup for why refcounting */ + bfqg_get(bfqg); +#endif + return &bfqg->pd; +} + +static void bfq_pd_init(struct blkg_policy_data *pd) +{ + struct blkcg_gq *blkg; + struct bfq_group *bfqg; + struct bfq_data *bfqd; + struct bfq_entity *entity; + struct bfq_group_data *d; + + blkg = pd_to_blkg(pd); + BUG_ON(!blkg); + bfqg = blkg_to_bfqg(blkg); + bfqd = blkg->q->elevator->elevator_data; + BUG_ON(bfqg == bfqd->root_group); + entity = &bfqg->entity; + d = blkcg_to_bfqgd(blkg->blkcg); + + entity->orig_weight = entity->weight = entity->new_weight = d->weight; + entity->my_sched_data = &bfqg->sched_data; + bfqg->my_entity = entity; /* + * the root_group's will be set to NULL + * in bfq_init_queue() + */ + bfqg->bfqd = bfqd; + bfqg->active_entities = 0; + bfqg->rq_pos_tree = RB_ROOT; +} + +static void bfq_pd_free(struct blkg_policy_data *pd) +{ + struct bfq_group *bfqg = pd_to_bfqg(pd); + + bfqg_stats_exit(&bfqg->stats); +#ifdef BFQ_MQ + bfqg_put(bfqg); +#else + kfree(bfqg); +#endif +} + +static void bfq_pd_reset_stats(struct blkg_policy_data *pd) +{ + struct bfq_group *bfqg = pd_to_bfqg(pd); + + bfqg_stats_reset(&bfqg->stats); +} + +static void bfq_group_set_parent(struct bfq_group *bfqg, + struct bfq_group *parent) +{ + struct bfq_entity *entity; + + BUG_ON(!parent); + BUG_ON(!bfqg); + BUG_ON(bfqg == parent); + + entity = &bfqg->entity; + entity->parent = parent->my_entity; + entity->sched_data = &parent->sched_data; +} + +static struct bfq_group *bfq_lookup_bfqg(struct bfq_data *bfqd, + struct blkcg *blkcg) +{ + struct blkcg_gq *blkg; + + blkg = blkg_lookup(blkcg, bfqd->queue); + if (likely(blkg)) + return blkg_to_bfqg(blkg); + return NULL; +} + +static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, + struct blkcg *blkcg) +{ + struct bfq_group *bfqg, *parent; + struct bfq_entity *entity; + + bfqg = bfq_lookup_bfqg(bfqd, blkcg); + + if (unlikely(!bfqg)) + return NULL; + + /* + * Update chain of bfq_groups as we might be handling a leaf group + * which, along with some of its relatives, has not been hooked yet + * to the private hierarchy of BFQ. + */ + entity = &bfqg->entity; + for_each_entity(entity) { + bfqg = container_of(entity, struct bfq_group, entity); + BUG_ON(!bfqg); + if (bfqg != bfqd->root_group) { + parent = bfqg_parent(bfqg); + if (!parent) + parent = bfqd->root_group; + BUG_ON(!parent); + bfq_group_set_parent(bfqg, parent); + } + } + + return bfqg; +} + +static void bfq_pos_tree_add_move(struct bfq_data *bfqd, + struct bfq_queue *bfqq); + +static void bfq_bfqq_expire(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool compensate, + enum bfqq_expiration reason); + +/** + * bfq_bfqq_move - migrate @bfqq to @bfqg. + * @bfqd: queue descriptor. + * @bfqq: the queue to move. + * @bfqg: the group to move to. + * + * Move @bfqq to @bfqg, deactivating it from its old group and reactivating + * it on the new one. Avoid putting the entity on the old group idle tree. + * +#ifdef BFQ_MQ + * Must be called under the scheduler lock, to make sure that the blkg + * owning @bfqg does not disappear (see comments in + * bfq_bic_update_cgroup on guaranteeing the consistency of blkg + * objects). +#else + * Must be called under the queue lock; the cgroup owning @bfqg must + * not disappear (by now this just means that we are called under + * rcu_read_lock()). +#endif + */ +static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct bfq_group *bfqg) +{ + struct bfq_entity *entity = &bfqq->entity; + + BUG_ON(!bfq_bfqq_busy(bfqq) && !RB_EMPTY_ROOT(&bfqq->sort_list)); + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list) && !entity->on_st); + BUG_ON(bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list) + && entity->on_st && + bfqq != bfqd->in_service_queue); + BUG_ON(!bfq_bfqq_busy(bfqq) && bfqq == bfqd->in_service_queue); + + /* If bfqq is empty, then bfq_bfqq_expire also invokes + * bfq_del_bfqq_busy, thereby removing bfqq and its entity + * from data structures related to current group. Otherwise we + * need to remove bfqq explicitly with bfq_deactivate_bfqq, as + * we do below. + */ + if (bfqq == bfqd->in_service_queue) + bfq_bfqq_expire(bfqd, bfqd->in_service_queue, + false, BFQ_BFQQ_PREEMPTED); + + BUG_ON(entity->on_st && !bfq_bfqq_busy(bfqq) + && &bfq_entity_service_tree(entity)->idle != + entity->tree); + + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_busy(bfqq)); + + if (bfq_bfqq_busy(bfqq)) + bfq_deactivate_bfqq(bfqd, bfqq, false, false); + else if (entity->on_st) { + BUG_ON(&bfq_entity_service_tree(entity)->idle != + entity->tree); + bfq_put_idle_entity(bfq_entity_service_tree(entity), entity); + } +#ifdef BFQ_MQ + bfqg_and_blkg_put(bfqq_group(bfqq)); +#else + bfqg_put(bfqq_group(bfqq)); +#endif + + entity->parent = bfqg->my_entity; + entity->sched_data = &bfqg->sched_data; +#ifdef BFQ_MQ + /* pin down bfqg and its associated blkg */ + bfqg_and_blkg_get(bfqg); +#else + bfqg_get(bfqg); +#endif + + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_busy(bfqq)); + if (bfq_bfqq_busy(bfqq)) { + bfq_pos_tree_add_move(bfqd, bfqq); + bfq_activate_bfqq(bfqd, bfqq); + } + + if (!bfqd->in_service_queue && !bfqd->rq_in_driver) + bfq_schedule_dispatch(bfqd); + BUG_ON(entity->on_st && !bfq_bfqq_busy(bfqq) + && &bfq_entity_service_tree(entity)->idle != + entity->tree); +} + +/** + * __bfq_bic_change_cgroup - move @bic to @cgroup. + * @bfqd: the queue descriptor. + * @bic: the bic to move. + * @blkcg: the blk-cgroup to move to. + * +#ifdef BFQ_MQ + * Move bic to blkcg, assuming that bfqd->lock is held; which makes + * sure that the reference to cgroup is valid across the call (see + * comments in bfq_bic_update_cgroup on this issue) +#else + * Move bic to blkcg, assuming that bfqd->queue is locked; the caller + * has to make sure that the reference to cgroup is valid across the call. +#endif + * + * NOTE: an alternative approach might have been to store the current + * cgroup in bfqq and getting a reference to it, reducing the lookup + * time here, at the price of slightly more complex code. + */ +static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, + struct bfq_io_cq *bic, + struct blkcg *blkcg) +{ + struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0); + struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1); + struct bfq_group *bfqg; + struct bfq_entity *entity; + + bfqg = bfq_find_set_group(bfqd, blkcg); + + if (unlikely(!bfqg)) + bfqg = bfqd->root_group; + + if (async_bfqq) { + entity = &async_bfqq->entity; + + if (entity->sched_data != &bfqg->sched_data) { + bic_set_bfqq(bic, NULL, 0); + bfq_log_bfqq(bfqd, async_bfqq, + "bic_change_group: %p %d", + async_bfqq, + async_bfqq->ref); + bfq_put_queue(async_bfqq); + } + } + + if (sync_bfqq) { + entity = &sync_bfqq->entity; + if (entity->sched_data != &bfqg->sched_data) + bfq_bfqq_move(bfqd, sync_bfqq, bfqg); + } + + return bfqg; +} + +static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) +{ + struct bfq_data *bfqd = bic_to_bfqd(bic); + struct bfq_group *bfqg = NULL; + uint64_t serial_nr; + + rcu_read_lock(); + serial_nr = bio_blkcg(bio)->css.serial_nr; + + /* + * Check whether blkcg has changed. The condition may trigger + * spuriously on a newly created cic but there's no harm. + */ + if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr)) + goto out; + + bfqg = __bfq_bic_change_cgroup(bfqd, bic, bio_blkcg(bio)); +#ifdef BFQ_MQ + /* + * Update blkg_path for bfq_log_* functions. We cache this + * path, and update it here, for the following + * reasons. Operations on blkg objects in blk-cgroup are + * protected with the request_queue lock, and not with the + * lock that protects the instances of this scheduler + * (bfqd->lock). This exposes BFQ to the following sort of + * race. + * + * The blkg_lookup performed in bfq_get_queue, protected + * through rcu, may happen to return the address of a copy of + * the original blkg. If this is the case, then the + * bfqg_and_blkg_get performed in bfq_get_queue, to pin down + * the blkg, is useless: it does not prevent blk-cgroup code + * from destroying both the original blkg and all objects + * directly or indirectly referred by the copy of the + * blkg. + * + * On the bright side, destroy operations on a blkg invoke, as + * a first step, hooks of the scheduler associated with the + * blkg. And these hooks are executed with bfqd->lock held for + * BFQ. As a consequence, for any blkg associated with the + * request queue this instance of the scheduler is attached + * to, we are guaranteed that such a blkg is not destroyed, and + * that all the pointers it contains are consistent, while we + * are holding bfqd->lock. A blkg_lookup performed with + * bfqd->lock held then returns a fully consistent blkg, which + * remains consistent until this lock is held. + * + * Thanks to the last fact, and to the fact that: (1) bfqg has + * been obtained through a blkg_lookup in the above + * assignment, and (2) bfqd->lock is being held, here we can + * safely use the policy data for the involved blkg (i.e., the + * field bfqg->pd) to get to the blkg associated with bfqg, + * and then we can safely use any field of blkg. After we + * release bfqd->lock, even just getting blkg through this + * bfqg may cause dangling references to be traversed, as + * bfqg->pd may not exist any more. + * + * In view of the above facts, here we cache, in the bfqg, any + * blkg data we may need for this bic, and for its associated + * bfq_queue. As of now, we need to cache only the path of the + * blkg, which is used in the bfq_log_* functions. + * + * Finally, note that bfqg itself needs to be protected from + * destruction on the blkg_free of the original blkg (which + * invokes bfq_pd_free). We use an additional private + * refcounter for bfqg, to let it disappear only after no + * bfq_queue refers to it any longer. + */ + blkg_path(bfqg_to_blkg(bfqg), bfqg->blkg_path, sizeof(bfqg->blkg_path)); +#endif + bic->blkcg_serial_nr = serial_nr; +out: + rcu_read_unlock(); +} + +/** + * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st. + * @st: the service tree being flushed. + */ +static void bfq_flush_idle_tree(struct bfq_service_tree *st) +{ + struct bfq_entity *entity = st->first_idle; + + for (; entity ; entity = st->first_idle) + __bfq_deactivate_entity(entity, false); +} + +/** + * bfq_reparent_leaf_entity - move leaf entity to the root_group. + * @bfqd: the device data structure with the root group. + * @entity: the entity to move. + */ +static void bfq_reparent_leaf_entity(struct bfq_data *bfqd, + struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + BUG_ON(!bfqq); + bfq_bfqq_move(bfqd, bfqq, bfqd->root_group); +} + +/** + * bfq_reparent_active_entities - move to the root group all active + * entities. + * @bfqd: the device data structure with the root group. + * @bfqg: the group to move from. + * @st: the service tree with the entities. + */ +static void bfq_reparent_active_entities(struct bfq_data *bfqd, + struct bfq_group *bfqg, + struct bfq_service_tree *st) +{ + struct rb_root *active = &st->active; + struct bfq_entity *entity = NULL; + + if (!RB_EMPTY_ROOT(&st->active)) + entity = bfq_entity_of(rb_first(active)); + + for (; entity ; entity = bfq_entity_of(rb_first(active))) + bfq_reparent_leaf_entity(bfqd, entity); + + if (bfqg->sched_data.in_service_entity) + bfq_reparent_leaf_entity(bfqd, + bfqg->sched_data.in_service_entity); +} + +/** + * bfq_pd_offline - deactivate the entity associated with @pd, + * and reparent its children entities. + * @pd: descriptor of the policy going offline. + * + * blkio already grabs the queue_lock for us, so no need to use + * RCU-based magic + */ +static void bfq_pd_offline(struct blkg_policy_data *pd) +{ + struct bfq_service_tree *st; + struct bfq_group *bfqg; + struct bfq_data *bfqd; + struct bfq_entity *entity; +#ifdef BFQ_MQ + unsigned long flags; +#endif + int i; + + BUG_ON(!pd); + bfqg = pd_to_bfqg(pd); + BUG_ON(!bfqg); + bfqd = bfqg->bfqd; + BUG_ON(bfqd && !bfqd->root_group); + + entity = bfqg->my_entity; + + if (!entity) /* root group */ + return; + +#ifdef BFQ_MQ + spin_lock_irqsave(&bfqd->lock, flags); +#endif + + /* + * Empty all service_trees belonging to this group before + * deactivating the group itself. + */ + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) { + BUG_ON(!bfqg->sched_data.service_tree); + st = bfqg->sched_data.service_tree + i; + /* + * The idle tree may still contain bfq_queues belonging + * to exited task because they never migrated to a different + * cgroup from the one being destroyed now. + */ + bfq_flush_idle_tree(st); + + /* + * It may happen that some queues are still active + * (busy) upon group destruction (if the corresponding + * processes have been forced to terminate). We move + * all the leaf entities corresponding to these queues + * to the root_group. + * Also, it may happen that the group has an entity + * in service, which is disconnected from the active + * tree: it must be moved, too. + * There is no need to put the sync queues, as the + * scheduler has taken no reference. + */ + bfq_reparent_active_entities(bfqd, bfqg, st); + BUG_ON(!RB_EMPTY_ROOT(&st->active)); + BUG_ON(!RB_EMPTY_ROOT(&st->idle)); + } + BUG_ON(bfqg->sched_data.next_in_service); + BUG_ON(bfqg->sched_data.in_service_entity); + + __bfq_deactivate_entity(entity, false); + bfq_put_async_queues(bfqd, bfqg); + +#ifdef BFQ_MQ + spin_unlock_irqrestore(&bfqd->lock, flags); +#endif + /* + * @blkg is going offline and will be ignored by + * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so + * that they don't get lost. If IOs complete after this point, the + * stats for them will be lost. Oh well... + */ + bfqg_stats_xfer_dead(bfqg); +} + +static void bfq_end_wr_async(struct bfq_data *bfqd) +{ + struct blkcg_gq *blkg; + + list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) { + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + BUG_ON(!bfqg); + + bfq_end_wr_async_queues(bfqd, bfqg); + } + bfq_end_wr_async_queues(bfqd, bfqd->root_group); +} + +static int bfq_io_show_weight(struct seq_file *sf, void *v) +{ + struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); + struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); + unsigned int val = 0; + + if (bfqgd) + val = bfqgd->weight; + + seq_printf(sf, "%u\n", val); + + return 0; +} + +static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css, + struct cftype *cftype, + u64 val) +{ + struct blkcg *blkcg = css_to_blkcg(css); + struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); + struct blkcg_gq *blkg; + int ret = -ERANGE; + + if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT) + return ret; + + ret = 0; + spin_lock_irq(&blkcg->lock); + bfqgd->weight = (unsigned short)val; + hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + + if (!bfqg) + continue; + /* + * Setting the prio_changed flag of the entity + * to 1 with new_weight == weight would re-set + * the value of the weight to its ioprio mapping. + * Set the flag only if necessary. + */ + if ((unsigned short)val != bfqg->entity.new_weight) { + bfqg->entity.new_weight = (unsigned short)val; + /* + * Make sure that the above new value has been + * stored in bfqg->entity.new_weight before + * setting the prio_changed flag. In fact, + * this flag may be read asynchronously (in + * critical sections protected by a different + * lock than that held here), and finding this + * flag set may cause the execution of the code + * for updating parameters whose value may + * depend also on bfqg->entity.new_weight (in + * __bfq_entity_update_weight_prio). + * This barrier makes sure that the new value + * of bfqg->entity.new_weight is correctly + * seen in that code. + */ + smp_wmb(); + bfqg->entity.prio_changed = 1; + } + } + spin_unlock_irq(&blkcg->lock); + + return ret; +} + +static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + u64 weight; + /* First unsigned long found in the file is used */ + int ret = kstrtoull(strim(buf), 0, &weight); + + if (ret) + return ret; + + return bfq_io_set_weight_legacy(of_css(of), NULL, weight); +} + +static int bfqg_print_stat(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat, + &blkcg_policy_bfq, seq_cft(sf)->private, false); + return 0; +} + +static int bfqg_print_rwstat(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat, + &blkcg_policy_bfq, seq_cft(sf)->private, true); + return 0; +} + +static u64 bfqg_prfill_stat_recursive(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd), + &blkcg_policy_bfq, off); + return __blkg_prfill_u64(sf, pd, sum); +} + +static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd), + &blkcg_policy_bfq, + off); + return __blkg_prfill_rwstat(sf, pd, &sum); +} + +static int bfqg_print_stat_recursive(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_stat_recursive, &blkcg_policy_bfq, + seq_cft(sf)->private, false); + return 0; +} + +static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq, + seq_cft(sf)->private, true); + return 0; +} + +static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd, + int off) +{ + u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes); + + return __blkg_prfill_u64(sf, pd, sum >> 9); +} + +static int bfqg_print_stat_sectors(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false); + return 0; +} + +static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL, + offsetof(struct blkcg_gq, stat_bytes)); + u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) + + atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]); + + return __blkg_prfill_u64(sf, pd, sum >> 9); +} + +static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0, + false); + return 0; +} + + +static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + struct bfq_group *bfqg = pd_to_bfqg(pd); + u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples); + u64 v = 0; + + if (samples) { + v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum); + v = div64_u64(v, samples); + } + __blkg_prfill_u64(sf, pd, v); + return 0; +} + +/* print avg_queue_size */ +static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_avg_queue_size, &blkcg_policy_bfq, + 0, false); + return 0; +} + +static struct bfq_group * +bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) +{ + int ret; + + ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq); + if (ret) + return NULL; + + return blkg_to_bfqg(bfqd->queue->root_blkg); +} + +#ifdef BFQ_MQ +#define BFQ_CGROUP_FNAME(param) "bfq-mq."#param +#else +#define BFQ_CGROUP_FNAME(param) "bfq-sq."#param +#endif + +static struct cftype bfq_blkcg_legacy_files[] = { + { + .name = BFQ_CGROUP_FNAME(weight), + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = bfq_io_show_weight, + .write_u64 = bfq_io_set_weight_legacy, + }, + + /* statistics, covers only the tasks in the bfqg */ + { + .name = BFQ_CGROUP_FNAME(time), + .private = offsetof(struct bfq_group, stats.time), + .seq_show = bfqg_print_stat, + }, + { + .name = BFQ_CGROUP_FNAME(sectors), + .seq_show = bfqg_print_stat_sectors, + }, + { + .name = BFQ_CGROUP_FNAME(io_service_bytes), + .private = (unsigned long)&blkcg_policy_bfq, + .seq_show = blkg_print_stat_bytes, + }, + { + .name = BFQ_CGROUP_FNAME(io_serviced), + .private = (unsigned long)&blkcg_policy_bfq, + .seq_show = blkg_print_stat_ios, + }, + { + .name = BFQ_CGROUP_FNAME(io_service_time), + .private = offsetof(struct bfq_group, stats.service_time), + .seq_show = bfqg_print_rwstat, + }, + { + .name = BFQ_CGROUP_FNAME(io_wait_time), + .private = offsetof(struct bfq_group, stats.wait_time), + .seq_show = bfqg_print_rwstat, + }, + { + .name = BFQ_CGROUP_FNAME(io_merged), + .private = offsetof(struct bfq_group, stats.merged), + .seq_show = bfqg_print_rwstat, + }, + { + .name = BFQ_CGROUP_FNAME(io_queued), + .private = offsetof(struct bfq_group, stats.queued), + .seq_show = bfqg_print_rwstat, + }, + + /* the same statictics which cover the bfqg and its descendants */ + { + .name = BFQ_CGROUP_FNAME(time_recursive), + .private = offsetof(struct bfq_group, stats.time), + .seq_show = bfqg_print_stat_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(sectors_recursive), + .seq_show = bfqg_print_stat_sectors_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_service_bytes_recursive), + .private = (unsigned long)&blkcg_policy_bfq, + .seq_show = blkg_print_stat_bytes_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_serviced_recursive), + .private = (unsigned long)&blkcg_policy_bfq, + .seq_show = blkg_print_stat_ios_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_service_time_recursive), + .private = offsetof(struct bfq_group, stats.service_time), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_wait_time_recursive), + .private = offsetof(struct bfq_group, stats.wait_time), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_merged_recursive), + .private = offsetof(struct bfq_group, stats.merged), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(io_queued_recursive), + .private = offsetof(struct bfq_group, stats.queued), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = BFQ_CGROUP_FNAME(avg_queue_size), + .seq_show = bfqg_print_avg_queue_size, + }, + { + .name = BFQ_CGROUP_FNAME(group_wait_time), + .private = offsetof(struct bfq_group, stats.group_wait_time), + .seq_show = bfqg_print_stat, + }, + { + .name = BFQ_CGROUP_FNAME(idle_time), + .private = offsetof(struct bfq_group, stats.idle_time), + .seq_show = bfqg_print_stat, + }, + { + .name = BFQ_CGROUP_FNAME(empty_time), + .private = offsetof(struct bfq_group, stats.empty_time), + .seq_show = bfqg_print_stat, + }, + { + .name = BFQ_CGROUP_FNAME(dequeue), + .private = offsetof(struct bfq_group, stats.dequeue), + .seq_show = bfqg_print_stat, + }, + { } /* terminate */ +}; + +static struct cftype bfq_blkg_files[] = { + { + .name = BFQ_CGROUP_FNAME(weight), + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = bfq_io_show_weight, + .write = bfq_io_set_weight, + }, + {} /* terminate */ +}; + +#undef BFQ_CGROUP_FNAME + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ + +static inline void bfqg_stats_update_io_add(struct bfq_group *bfqg, + struct bfq_queue *bfqq, unsigned int op) { } +static inline void +bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op) { } +static inline void +bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) { } +static inline void bfqg_stats_update_completion(struct bfq_group *bfqg, + uint64_t start_time, uint64_t io_start_time, + unsigned int op) { } +static inline void +bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, + struct bfq_group *curr_bfqg) { } +static inline void bfqg_stats_end_empty_time(struct bfqg_stats *stats) { } +static inline void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { } +static inline void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) { } +static inline void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { } +static inline void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { } +static inline void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) { } + +static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct bfq_group *bfqg) {} + +static void bfq_init_entity(struct bfq_entity *entity, + struct bfq_group *bfqg) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + entity->weight = entity->new_weight; + entity->orig_weight = entity->new_weight; + if (bfqq) { + bfqq->ioprio = bfqq->new_ioprio; + bfqq->ioprio_class = bfqq->new_ioprio_class; + } + entity->sched_data = &bfqg->sched_data; +} + +static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) {} + +static void bfq_end_wr_async(struct bfq_data *bfqd) +{ + bfq_end_wr_async_queues(bfqd, bfqd->root_group); +} + +static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, + struct blkcg *blkcg) +{ + return bfqd->root_group; +} + +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq) +{ + return bfqq->bfqd->root_group; +} + +static struct bfq_group * +bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) +{ + struct bfq_group *bfqg; + int i; + + bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node); + if (!bfqg) + return NULL; + + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) + bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; + + return bfqg; +} +#endif diff --git b/block/bfq-ioc.c b/block/bfq-ioc.c new file mode 100644 index 0000000..fb7bb8f --- /dev/null +++ b/block/bfq-ioc.c @@ -0,0 +1,36 @@ +/* + * BFQ: I/O context handling. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2010 Paolo Valente + */ + +/** + * icq_to_bic - convert iocontext queue structure to bfq_io_cq. + * @icq: the iocontext queue. + */ +static struct bfq_io_cq *icq_to_bic(struct io_cq *icq) +{ + /* bic->icq is the first member, %NULL will convert to %NULL */ + return container_of(icq, struct bfq_io_cq, icq); +} + +/** + * bfq_bic_lookup - search into @ioc a bic associated to @bfqd. + * @bfqd: the lookup key. + * @ioc: the io_context of the process doing I/O. + * + * Queue lock must be held. + */ +static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, + struct io_context *ioc) +{ + if (ioc) + return icq_to_bic(ioc_lookup_icq(ioc, bfqd->queue)); + return NULL; +} diff --git b/block/bfq-mq-iosched.c b/block/bfq-mq-iosched.c new file mode 100644 index 0000000..8c5dce7 --- /dev/null +++ b/block/bfq-mq-iosched.c @@ -0,0 +1,5693 @@ +/* + * Budget Fair Queueing (BFQ) I/O scheduler. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2017 Paolo Valente + * + * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ + * file. + * + * BFQ is a proportional-share I/O scheduler, with some extra + * low-latency capabilities. BFQ also supports full hierarchical + * scheduling through cgroups. Next paragraphs provide an introduction + * on BFQ inner workings. Details on BFQ benefits and usage can be + * found in Documentation/block/bfq-iosched.txt. + * + * BFQ is a proportional-share storage-I/O scheduling algorithm based + * on the slice-by-slice service scheme of CFQ. But BFQ assigns + * budgets, measured in number of sectors, to processes instead of + * time slices. The device is not granted to the in-service process + * for a given time slice, but until it has exhausted its assigned + * budget. This change from the time to the service domain enables BFQ + * to distribute the device throughput among processes as desired, + * without any distortion due to throughput fluctuations, or to device + * internal queueing. BFQ uses an ad hoc internal scheduler, called + * B-WF2Q+, to schedule processes according to their budgets. More + * precisely, BFQ schedules queues associated with processes. Thanks to + * the accurate policy of B-WF2Q+, BFQ can afford to assign high + * budgets to I/O-bound processes issuing sequential requests (to + * boost the throughput), and yet guarantee a low latency to + * interactive and soft real-time applications. + * + * NOTE: if the main or only goal, with a given device, is to achieve + * the maximum-possible throughput at all times, then do switch off + * all low-latency heuristics for that device, by setting low_latency + * to 0. + * + * BFQ is described in [1], where also a reference to the initial, more + * theoretical paper on BFQ can be found. The interested reader can find + * in the latter paper full details on the main algorithm, as well as + * formulas of the guarantees and formal proofs of all the properties. + * With respect to the version of BFQ presented in these papers, this + * implementation adds a few more heuristics, such as the one that + * guarantees a low latency to soft real-time applications, and a + * hierarchical extension based on H-WF2Q+. + * + * B-WF2Q+ is based on WF2Q+, that is described in [2], together with + * H-WF2Q+, while the augmented tree used to implement B-WF2Q+ with O(log N) + * complexity derives from the one introduced with EEVDF in [3]. + * + * [1] P. Valente, A. Avanzini, "Evolution of the BFQ Storage I/O + * Scheduler", Proceedings of the First Workshop on Mobile System + * Technologies (MST-2015), May 2015. + * http://algogroup.unimore.it/people/paolo/disk_sched/mst-2015.pdf + * + * http://algogroup.unimo.it/people/paolo/disk_sched/bf1-v1-suite-results.pdf + * + * [2] Jon C.R. Bennett and H. Zhang, ``Hierarchical Packet Fair Queueing + * Algorithms,'' IEEE/ACM Transactions on Networking, 5(5):675-689, + * Oct 1997. + * + * http://www.cs.cmu.edu/~hzhang/papers/TON-97-Oct.ps.gz + * + * [3] I. Stoica and H. Abdel-Wahab, ``Earliest Eligible Virtual Deadline + * First: A Flexible and Accurate Mechanism for Proportional Share + * Resource Allocation,'' technical report. + * + * http://www.cs.berkeley.edu/~istoica/papers/eevdf-tr-95.pdf + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "blk.h" +#include "blk-mq.h" +#include "blk-mq-tag.h" +#include "blk-mq-sched.h" +#include "bfq-mq.h" + +/* Expiration time of sync (0) and async (1) requests, in ns. */ +static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 }; + +/* Maximum backwards seek, in KiB. */ +static const int bfq_back_max = (16 * 1024); + +/* Penalty of a backwards seek, in number of sectors. */ +static const int bfq_back_penalty = 2; + +/* Idling period duration, in ns. */ +static u32 bfq_slice_idle = (NSEC_PER_SEC / 125); + +/* Minimum number of assigned budgets for which stats are safe to compute. */ +static const int bfq_stats_min_budgets = 194; + +/* Default maximum budget values, in sectors and number of requests. */ +static const int bfq_default_max_budget = (16 * 1024); + +/* + * Async to sync throughput distribution is controlled as follows: + * when an async request is served, the entity is charged the number + * of sectors of the request, multiplied by the factor below + */ +static const int bfq_async_charge_factor = 10; + +/* Default timeout values, in jiffies, approximating CFQ defaults. */ +static const int bfq_timeout = (HZ / 8); + +static struct kmem_cache *bfq_pool; + +/* Below this threshold (in ns), we consider thinktime immediate. */ +#define BFQ_MIN_TT (2 * NSEC_PER_MSEC) + +/* hw_tag detection: parallel requests threshold and min samples needed. */ +#define BFQ_HW_QUEUE_THRESHOLD 4 +#define BFQ_HW_QUEUE_SAMPLES 32 + +#define BFQQ_SEEK_THR (sector_t)(8 * 100) +#define BFQQ_SECT_THR_NONROT (sector_t)(2 * 32) +#define BFQQ_CLOSE_THR (sector_t)(8 * 1024) +#define BFQQ_SEEKY(bfqq) (hweight32(bfqq->seek_history) > 32/8) + +/* Min number of samples required to perform peak-rate update */ +#define BFQ_RATE_MIN_SAMPLES 32 +/* Min observation time interval required to perform a peak-rate update (ns) */ +#define BFQ_RATE_MIN_INTERVAL (300*NSEC_PER_MSEC) +/* Target observation time interval for a peak-rate update (ns) */ +#define BFQ_RATE_REF_INTERVAL NSEC_PER_SEC + +/* Shift used for peak rate fixed precision calculations. */ +#define BFQ_RATE_SHIFT 16 + +/* + * By default, BFQ computes the duration of the weight raising for + * interactive applications automatically, using the following formula: + * duration = (R / r) * T, where r is the peak rate of the device, and + * R and T are two reference parameters. + * In particular, R is the peak rate of the reference device (see below), + * and T is a reference time: given the systems that are likely to be + * installed on the reference device according to its speed class, T is + * about the maximum time needed, under BFQ and while reading two files in + * parallel, to load typical large applications on these systems. + * In practice, the slower/faster the device at hand is, the more/less it + * takes to load applications with respect to the reference device. + * Accordingly, the longer/shorter BFQ grants weight raising to interactive + * applications. + * + * BFQ uses four different reference pairs (R, T), depending on: + * . whether the device is rotational or non-rotational; + * . whether the device is slow, such as old or portable HDDs, as well as + * SD cards, or fast, such as newer HDDs and SSDs. + * + * The device's speed class is dynamically (re)detected in + * bfq_update_peak_rate() every time the estimated peak rate is updated. + * + * In the following definitions, R_slow[0]/R_fast[0] and + * T_slow[0]/T_fast[0] are the reference values for a slow/fast + * rotational device, whereas R_slow[1]/R_fast[1] and + * T_slow[1]/T_fast[1] are the reference values for a slow/fast + * non-rotational device. Finally, device_speed_thresh are the + * thresholds used to switch between speed classes. The reference + * rates are not the actual peak rates of the devices used as a + * reference, but slightly lower values. The reason for using these + * slightly lower values is that the peak-rate estimator tends to + * yield slightly lower values than the actual peak rate (it can yield + * the actual peak rate only if there is only one process doing I/O, + * and the process does sequential I/O). + * + * Both the reference peak rates and the thresholds are measured in + * sectors/usec, left-shifted by BFQ_RATE_SHIFT. + */ +static int R_slow[2] = {1000, 10700}; +static int R_fast[2] = {14000, 33000}; +/* + * To improve readability, a conversion function is used to initialize the + * following arrays, which entails that they can be initialized only in a + * function. + */ +static int T_slow[2]; +static int T_fast[2]; +static int device_speed_thresh[2]; + +#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ + { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) + +#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) +#define RQ_BFQQ(rq) ((rq)->elv.priv[1]) + +/** + * icq_to_bic - convert iocontext queue structure to bfq_io_cq. + * @icq: the iocontext queue. + */ +static struct bfq_io_cq *icq_to_bic(struct io_cq *icq) +{ + /* bic->icq is the first member, %NULL will convert to %NULL */ + return container_of(icq, struct bfq_io_cq, icq); +} + +/** + * bfq_bic_lookup - search into @ioc a bic associated to @bfqd. + * @bfqd: the lookup key. + * @ioc: the io_context of the process doing I/O. + * @q: the request queue. + */ +static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, + struct io_context *ioc, + struct request_queue *q) +{ + if (ioc) { + unsigned long flags; + struct bfq_io_cq *icq; + + spin_lock_irqsave(q->queue_lock, flags); + icq = icq_to_bic(ioc_lookup_icq(ioc, q)); + spin_unlock_irqrestore(q->queue_lock, flags); + + return icq; + } + + return NULL; +} + +/* + * Scheduler run of queue, if there are requests pending and no one in the + * driver that will restart queueing. + */ +static void bfq_schedule_dispatch(struct bfq_data *bfqd) +{ + if (bfqd->queued != 0) { + bfq_log(bfqd, "schedule dispatch"); + blk_mq_run_hw_queues(bfqd->queue, true); + } +} + +#define BFQ_MQ +#include "bfq-sched.c" +#include "bfq-cgroup-included.c" + +#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE) +#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT) + +#define bfq_sample_valid(samples) ((samples) > 80) + +/* + * Lifted from AS - choose which of rq1 and rq2 that is best served now. + * We choose the request that is closesr to the head right now. Distance + * behind the head is penalized and only allowed to a certain extent. + */ +static struct request *bfq_choose_req(struct bfq_data *bfqd, + struct request *rq1, + struct request *rq2, + sector_t last) +{ + sector_t s1, s2, d1 = 0, d2 = 0; + unsigned long back_max; +#define BFQ_RQ1_WRAP 0x01 /* request 1 wraps */ +#define BFQ_RQ2_WRAP 0x02 /* request 2 wraps */ + unsigned int wrap = 0; /* bit mask: requests behind the disk head? */ + + if (!rq1 || rq1 == rq2) + return rq2; + if (!rq2) + return rq1; + + if (rq_is_sync(rq1) && !rq_is_sync(rq2)) + return rq1; + else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) + return rq2; + if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) + return rq1; + else if ((rq2->cmd_flags & REQ_META) && !(rq1->cmd_flags & REQ_META)) + return rq2; + + s1 = blk_rq_pos(rq1); + s2 = blk_rq_pos(rq2); + + /* + * By definition, 1KiB is 2 sectors. + */ + back_max = bfqd->bfq_back_max * 2; + + /* + * Strict one way elevator _except_ in the case where we allow + * short backward seeks which are biased as twice the cost of a + * similar forward seek. + */ + if (s1 >= last) + d1 = s1 - last; + else if (s1 + back_max >= last) + d1 = (last - s1) * bfqd->bfq_back_penalty; + else + wrap |= BFQ_RQ1_WRAP; + + if (s2 >= last) + d2 = s2 - last; + else if (s2 + back_max >= last) + d2 = (last - s2) * bfqd->bfq_back_penalty; + else + wrap |= BFQ_RQ2_WRAP; + + /* Found required data */ + + /* + * By doing switch() on the bit mask "wrap" we avoid having to + * check two variables for all permutations: --> faster! + */ + switch (wrap) { + case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ + if (d1 < d2) + return rq1; + else if (d2 < d1) + return rq2; + + if (s1 >= s2) + return rq1; + else + return rq2; + + case BFQ_RQ2_WRAP: + return rq1; + case BFQ_RQ1_WRAP: + return rq2; + case (BFQ_RQ1_WRAP|BFQ_RQ2_WRAP): /* both rqs wrapped */ + default: + /* + * Since both rqs are wrapped, + * start with the one that's further behind head + * (--> only *one* back seek required), + * since back seek takes more time than forward. + */ + if (s1 <= s2) + return rq1; + else + return rq2; + } +} + +static struct bfq_queue * +bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root, + sector_t sector, struct rb_node **ret_parent, + struct rb_node ***rb_link) +{ + struct rb_node **p, *parent; + struct bfq_queue *bfqq = NULL; + + parent = NULL; + p = &root->rb_node; + while (*p) { + struct rb_node **n; + + parent = *p; + bfqq = rb_entry(parent, struct bfq_queue, pos_node); + + /* + * Sort strictly based on sector. Smallest to the left, + * largest to the right. + */ + if (sector > blk_rq_pos(bfqq->next_rq)) + n = &(*p)->rb_right; + else if (sector < blk_rq_pos(bfqq->next_rq)) + n = &(*p)->rb_left; + else + break; + p = n; + bfqq = NULL; + } + + *ret_parent = parent; + if (rb_link) + *rb_link = p; + + bfq_log(bfqd, "rq_pos_tree_lookup %llu: returning %d", + (unsigned long long) sector, + bfqq ? bfqq->pid : 0); + + return bfqq; +} + +static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct rb_node **p, *parent; + struct bfq_queue *__bfqq; + + if (bfqq->pos_root) { + rb_erase(&bfqq->pos_node, bfqq->pos_root); + bfqq->pos_root = NULL; + } + + if (bfq_class_idle(bfqq)) + return; + if (!bfqq->next_rq) + return; + + bfqq->pos_root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; + __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root, + blk_rq_pos(bfqq->next_rq), &parent, &p); + if (!__bfqq) { + rb_link_node(&bfqq->pos_node, parent, p); + rb_insert_color(&bfqq->pos_node, bfqq->pos_root); + } else + bfqq->pos_root = NULL; +} + +/* + * Tell whether there are active queues or groups with differentiated weights. + */ +static bool bfq_differentiated_weights(struct bfq_data *bfqd) +{ + /* + * For weights to differ, at least one of the trees must contain + * at least two nodes. + */ + return (!RB_EMPTY_ROOT(&bfqd->queue_weights_tree) && + (bfqd->queue_weights_tree.rb_node->rb_left || + bfqd->queue_weights_tree.rb_node->rb_right) +#ifdef BFQ_GROUP_IOSCHED_ENABLED + ) || + (!RB_EMPTY_ROOT(&bfqd->group_weights_tree) && + (bfqd->group_weights_tree.rb_node->rb_left || + bfqd->group_weights_tree.rb_node->rb_right) +#endif + ); +} + +/* + * The following function returns true if every queue must receive the + * same share of the throughput (this condition is used when deciding + * whether idling may be disabled, see the comments in the function + * bfq_bfqq_may_idle()). + * + * Such a scenario occurs when: + * 1) all active queues have the same weight, + * 2) all active groups at the same level in the groups tree have the same + * weight, + * 3) all active groups at the same level in the groups tree have the same + * number of children. + * + * Unfortunately, keeping the necessary state for evaluating exactly the + * above symmetry conditions would be quite complex and time-consuming. + * Therefore this function evaluates, instead, the following stronger + * sub-conditions, for which it is much easier to maintain the needed + * state: + * 1) all active queues have the same weight, + * 2) all active groups have the same weight, + * 3) all active groups have at most one active child each. + * In particular, the last two conditions are always true if hierarchical + * support and the cgroups interface are not enabled, thus no state needs + * to be maintained in this case. + */ +static bool bfq_symmetric_scenario(struct bfq_data *bfqd) +{ + return !bfq_differentiated_weights(bfqd); +} + +/* + * If the weight-counter tree passed as input contains no counter for + * the weight of the input entity, then add that counter; otherwise just + * increment the existing counter. + * + * Note that weight-counter trees contain few nodes in mostly symmetric + * scenarios. For example, if all queues have the same weight, then the + * weight-counter tree for the queues may contain at most one node. + * This holds even if low_latency is on, because weight-raised queues + * are not inserted in the tree. + * In most scenarios, the rate at which nodes are created/destroyed + * should be low too. + */ +static void bfq_weights_tree_add(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root) +{ + struct rb_node **new = &(root->rb_node), *parent = NULL; + + /* + * Do not insert if the entity is already associated with a + * counter, which happens if: + * 1) the entity is associated with a queue, + * 2) a request arrival has caused the queue to become both + * non-weight-raised, and hence change its weight, and + * backlogged; in this respect, each of the two events + * causes an invocation of this function, + * 3) this is the invocation of this function caused by the + * second event. This second invocation is actually useless, + * and we handle this fact by exiting immediately. More + * efficient or clearer solutions might possibly be adopted. + */ + if (entity->weight_counter) + return; + + while (*new) { + struct bfq_weight_counter *__counter = container_of(*new, + struct bfq_weight_counter, + weights_node); + parent = *new; + + if (entity->weight == __counter->weight) { + entity->weight_counter = __counter; + goto inc_counter; + } + if (entity->weight < __counter->weight) + new = &((*new)->rb_left); + else + new = &((*new)->rb_right); + } + + entity->weight_counter = kzalloc(sizeof(struct bfq_weight_counter), + GFP_ATOMIC); + + /* + * In the unlucky event of an allocation failure, we just + * exit. This will cause the weight of entity to not be + * considered in bfq_differentiated_weights, which, in its + * turn, causes the scenario to be deemed wrongly symmetric in + * case entity's weight would have been the only weight making + * the scenario asymmetric. On the bright side, no unbalance + * will however occur when entity becomes inactive again (the + * invocation of this function is triggered by an activation + * of entity). In fact, bfq_weights_tree_remove does nothing + * if !entity->weight_counter. + */ + if (unlikely(!entity->weight_counter)) + return; + + entity->weight_counter->weight = entity->weight; + rb_link_node(&entity->weight_counter->weights_node, parent, new); + rb_insert_color(&entity->weight_counter->weights_node, root); + +inc_counter: + entity->weight_counter->num_active++; +} + +/* + * Decrement the weight counter associated with the entity, and, if the + * counter reaches 0, remove the counter from the tree. + * See the comments to the function bfq_weights_tree_add() for considerations + * about overhead. + */ +static void bfq_weights_tree_remove(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root) +{ + if (!entity->weight_counter) + return; + + BUG_ON(RB_EMPTY_ROOT(root)); + BUG_ON(entity->weight_counter->weight != entity->weight); + + BUG_ON(!entity->weight_counter->num_active); + entity->weight_counter->num_active--; + if (entity->weight_counter->num_active > 0) + goto reset_entity_pointer; + + rb_erase(&entity->weight_counter->weights_node, root); + kfree(entity->weight_counter); + +reset_entity_pointer: + entity->weight_counter = NULL; +} + +/* + * Return expired entry, or NULL to just start from scratch in rbtree. + */ +static struct request *bfq_check_fifo(struct bfq_queue *bfqq, + struct request *last) +{ + struct request *rq; + + if (bfq_bfqq_fifo_expire(bfqq)) + return NULL; + + bfq_mark_bfqq_fifo_expire(bfqq); + + rq = rq_entry_fifo(bfqq->fifo.next); + + if (rq == last || ktime_get_ns() < rq->fifo_time) + return NULL; + + bfq_log_bfqq(bfqq->bfqd, bfqq, "check_fifo: returned %p", rq); + BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); + return rq; +} + +static struct request *bfq_find_next_rq(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + struct request *last) +{ + struct rb_node *rbnext = rb_next(&last->rb_node); + struct rb_node *rbprev = rb_prev(&last->rb_node); + struct request *next, *prev = NULL; + + BUG_ON(list_empty(&bfqq->fifo)); + + /* Follow expired path, else get first next available. */ + next = bfq_check_fifo(bfqq, last); + if (next) { + BUG_ON(next == last); + return next; + } + + BUG_ON(RB_EMPTY_NODE(&last->rb_node)); + + if (rbprev) + prev = rb_entry_rq(rbprev); + + if (rbnext) + next = rb_entry_rq(rbnext); + else { + rbnext = rb_first(&bfqq->sort_list); + if (rbnext && rbnext != &last->rb_node) + next = rb_entry_rq(rbnext); + } + + return bfq_choose_req(bfqd, next, prev, blk_rq_pos(last)); +} + +/* see the definition of bfq_async_charge_factor for details */ +static unsigned long bfq_serv_to_charge(struct request *rq, + struct bfq_queue *bfqq) +{ + if (bfq_bfqq_sync(bfqq) || bfqq->wr_coeff > 1) + return blk_rq_sectors(rq); + + /* + * If there are no weight-raised queues, then amplify service + * by just the async charge factor; otherwise amplify service + * by twice the async charge factor, to further reduce latency + * for weight-raised queues. + */ + if (bfqq->bfqd->wr_busy_queues == 0) + return blk_rq_sectors(rq) * bfq_async_charge_factor; + + return blk_rq_sectors(rq) * 2 * bfq_async_charge_factor; +} + +/** + * bfq_updated_next_req - update the queue after a new next_rq selection. + * @bfqd: the device data the queue belongs to. + * @bfqq: the queue to update. + * + * If the first request of a queue changes we make sure that the queue + * has enough budget to serve at least its first request (if the + * request has grown). We do this because if the queue has not enough + * budget for its first request, it has to go through two dispatch + * rounds to actually get it dispatched. + */ +static void bfq_updated_next_req(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + struct request *next_rq = bfqq->next_rq; + unsigned long new_budget; + + if (!next_rq) + return; + + if (bfqq == bfqd->in_service_queue) + /* + * In order not to break guarantees, budgets cannot be + * changed after an entity has been selected. + */ + return; + + BUG_ON(entity->tree != &st->active); + BUG_ON(entity == entity->sched_data->in_service_entity); + + new_budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)); + if (entity->budget != new_budget) { + entity->budget = new_budget; + bfq_log_bfqq(bfqd, bfqq, "updated next rq: new budget %lu", + new_budget); + bfq_requeue_bfqq(bfqd, bfqq, false); + } +} + +static unsigned int bfq_wr_duration(struct bfq_data *bfqd) +{ + u64 dur; + + if (bfqd->bfq_wr_max_time > 0) + return bfqd->bfq_wr_max_time; + + dur = bfqd->RT_prod; + do_div(dur, bfqd->peak_rate); + + /* + * Limit duration between 3 and 13 seconds. Tests show that + * higher values than 13 seconds often yield the opposite of + * the desired result, i.e., worsen responsiveness by letting + * non-interactive and non-soft-real-time applications + * preserve weight raising for a too long time interval. + * + * On the other end, lower values than 3 seconds make it + * difficult for most interactive tasks to complete their jobs + * before weight-raising finishes. + */ + if (dur > msecs_to_jiffies(13000)) + dur = msecs_to_jiffies(13000); + else if (dur < msecs_to_jiffies(3000)) + dur = msecs_to_jiffies(3000); + + return dur; +} + +static void +bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, + struct bfq_io_cq *bic, bool bfq_already_existing) +{ + unsigned int old_wr_coeff; + bool busy = bfq_already_existing && bfq_bfqq_busy(bfqq); + + if (bic->saved_has_short_ttime) + bfq_mark_bfqq_has_short_ttime(bfqq); + else + bfq_clear_bfqq_has_short_ttime(bfqq); + + if (bic->saved_IO_bound) + bfq_mark_bfqq_IO_bound(bfqq); + else + bfq_clear_bfqq_IO_bound(bfqq); + + if (unlikely(busy)) + old_wr_coeff = bfqq->wr_coeff; + + bfqq->ttime = bic->saved_ttime; + bfqq->wr_coeff = bic->saved_wr_coeff; + bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt; + BUG_ON(time_is_after_jiffies(bfqq->wr_start_at_switch_to_srt)); + bfqq->last_wr_start_finish = bic->saved_last_wr_start_finish; + bfqq->wr_cur_max_time = bic->saved_wr_cur_max_time; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); + + if (bfqq->wr_coeff > 1 && (bfq_bfqq_in_large_burst(bfqq) || + time_is_before_jiffies(bfqq->last_wr_start_finish + + bfqq->wr_cur_max_time))) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "resume state: switching off wr (%lu + %lu < %lu)", + bfqq->last_wr_start_finish, bfqq->wr_cur_max_time, + jiffies); + + bfqq->wr_coeff = 1; + } + + /* make sure weight will be updated, however we got here */ + bfqq->entity.prio_changed = 1; + + if (likely(!busy)) + return; + + if (old_wr_coeff == 1 && bfqq->wr_coeff > 1) { + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + } else if (old_wr_coeff > 1 && bfqq->wr_coeff == 1) { + bfqd->wr_busy_queues--; + BUG_ON(bfqd->wr_busy_queues < 0); + } +} + +static int bfqq_process_refs(struct bfq_queue *bfqq) +{ + int process_refs, io_refs; + + lockdep_assert_held(&bfqq->bfqd->lock); + + io_refs = bfqq->allocated; + process_refs = bfqq->ref - io_refs - bfqq->entity.on_st; + BUG_ON(process_refs < 0); + return process_refs; +} + +/* Empty burst list and add just bfqq (see comments to bfq_handle_burst) */ +static void bfq_reset_burst_list(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct bfq_queue *item; + struct hlist_node *n; + + hlist_for_each_entry_safe(item, n, &bfqd->burst_list, burst_list_node) + hlist_del_init(&item->burst_list_node); + hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); + bfqd->burst_size = 1; + bfqd->burst_parent_entity = bfqq->entity.parent; +} + +/* Add bfqq to the list of queues in current burst (see bfq_handle_burst) */ +static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + /* Increment burst size to take into account also bfqq */ + bfqd->burst_size++; + + bfq_log_bfqq(bfqd, bfqq, "add_to_burst %d", bfqd->burst_size); + + BUG_ON(bfqd->burst_size > bfqd->bfq_large_burst_thresh); + + if (bfqd->burst_size == bfqd->bfq_large_burst_thresh) { + struct bfq_queue *pos, *bfqq_item; + struct hlist_node *n; + + /* + * Enough queues have been activated shortly after each + * other to consider this burst as large. + */ + bfqd->large_burst = true; + bfq_log_bfqq(bfqd, bfqq, "add_to_burst: large burst started"); + + /* + * We can now mark all queues in the burst list as + * belonging to a large burst. + */ + hlist_for_each_entry(bfqq_item, &bfqd->burst_list, + burst_list_node) { + bfq_mark_bfqq_in_large_burst(bfqq_item); + bfq_log_bfqq(bfqd, bfqq_item, "marked in large burst"); + } + bfq_mark_bfqq_in_large_burst(bfqq); + bfq_log_bfqq(bfqd, bfqq, "marked in large burst"); + + /* + * From now on, and until the current burst finishes, any + * new queue being activated shortly after the last queue + * was inserted in the burst can be immediately marked as + * belonging to a large burst. So the burst list is not + * needed any more. Remove it. + */ + hlist_for_each_entry_safe(pos, n, &bfqd->burst_list, + burst_list_node) + hlist_del_init(&pos->burst_list_node); + } else /* + * Burst not yet large: add bfqq to the burst list. Do + * not increment the ref counter for bfqq, because bfqq + * is removed from the burst list before freeing bfqq + * in put_queue. + */ + hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); +} + +/* + * If many queues belonging to the same group happen to be created + * shortly after each other, then the processes associated with these + * queues have typically a common goal. In particular, bursts of queue + * creations are usually caused by services or applications that spawn + * many parallel threads/processes. Examples are systemd during boot, + * or git grep. To help these processes get their job done as soon as + * possible, it is usually better to not grant either weight-raising + * or device idling to their queues. + * + * In this comment we describe, firstly, the reasons why this fact + * holds, and, secondly, the next function, which implements the main + * steps needed to properly mark these queues so that they can then be + * treated in a different way. + * + * The above services or applications benefit mostly from a high + * throughput: the quicker the requests of the activated queues are + * cumulatively served, the sooner the target job of these queues gets + * completed. As a consequence, weight-raising any of these queues, + * which also implies idling the device for it, is almost always + * counterproductive. In most cases it just lowers throughput. + * + * On the other hand, a burst of queue creations may be caused also by + * the start of an application that does not consist of a lot of + * parallel I/O-bound threads. In fact, with a complex application, + * several short processes may need to be executed to start-up the + * application. In this respect, to start an application as quickly as + * possible, the best thing to do is in any case to privilege the I/O + * related to the application with respect to all other + * I/O. Therefore, the best strategy to start as quickly as possible + * an application that causes a burst of queue creations is to + * weight-raise all the queues created during the burst. This is the + * exact opposite of the best strategy for the other type of bursts. + * + * In the end, to take the best action for each of the two cases, the + * two types of bursts need to be distinguished. Fortunately, this + * seems relatively easy, by looking at the sizes of the bursts. In + * particular, we found a threshold such that only bursts with a + * larger size than that threshold are apparently caused by + * services or commands such as systemd or git grep. For brevity, + * hereafter we call just 'large' these bursts. BFQ *does not* + * weight-raise queues whose creation occurs in a large burst. In + * addition, for each of these queues BFQ performs or does not perform + * idling depending on which choice boosts the throughput more. The + * exact choice depends on the device and request pattern at + * hand. + * + * Unfortunately, false positives may occur while an interactive task + * is starting (e.g., an application is being started). The + * consequence is that the queues associated with the task do not + * enjoy weight raising as expected. Fortunately these false positives + * are very rare. They typically occur if some service happens to + * start doing I/O exactly when the interactive task starts. + * + * Turning back to the next function, it implements all the steps + * needed to detect the occurrence of a large burst and to properly + * mark all the queues belonging to it (so that they can then be + * treated in a different way). This goal is achieved by maintaining a + * "burst list" that holds, temporarily, the queues that belong to the + * burst in progress. The list is then used to mark these queues as + * belonging to a large burst if the burst does become large. The main + * steps are the following. + * + * . when the very first queue is created, the queue is inserted into the + * list (as it could be the first queue in a possible burst) + * + * . if the current burst has not yet become large, and a queue Q that does + * not yet belong to the burst is activated shortly after the last time + * at which a new queue entered the burst list, then the function appends + * Q to the burst list + * + * . if, as a consequence of the previous step, the burst size reaches + * the large-burst threshold, then + * + * . all the queues in the burst list are marked as belonging to a + * large burst + * + * . the burst list is deleted; in fact, the burst list already served + * its purpose (keeping temporarily track of the queues in a burst, + * so as to be able to mark them as belonging to a large burst in the + * previous sub-step), and now is not needed any more + * + * . the device enters a large-burst mode + * + * . if a queue Q that does not belong to the burst is created while + * the device is in large-burst mode and shortly after the last time + * at which a queue either entered the burst list or was marked as + * belonging to the current large burst, then Q is immediately marked + * as belonging to a large burst. + * + * . if a queue Q that does not belong to the burst is created a while + * later, i.e., not shortly after, than the last time at which a queue + * either entered the burst list or was marked as belonging to the + * current large burst, then the current burst is deemed as finished and: + * + * . the large-burst mode is reset if set + * + * . the burst list is emptied + * + * . Q is inserted in the burst list, as Q may be the first queue + * in a possible new burst (then the burst list contains just Q + * after this step). + */ +static void bfq_handle_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + /* + * If bfqq is already in the burst list or is part of a large + * burst, or finally has just been split, then there is + * nothing else to do. + */ + if (!hlist_unhashed(&bfqq->burst_list_node) || + bfq_bfqq_in_large_burst(bfqq) || + time_is_after_eq_jiffies(bfqq->split_time + + msecs_to_jiffies(10))) + return; + + /* + * If bfqq's creation happens late enough, or bfqq belongs to + * a different group than the burst group, then the current + * burst is finished, and related data structures must be + * reset. + * + * In this respect, consider the special case where bfqq is + * the very first queue created after BFQ is selected for this + * device. In this case, last_ins_in_burst and + * burst_parent_entity are not yet significant when we get + * here. But it is easy to verify that, whether or not the + * following condition is true, bfqq will end up being + * inserted into the burst list. In particular the list will + * happen to contain only bfqq. And this is exactly what has + * to happen, as bfqq may be the first queue of the first + * burst. + */ + if (time_is_before_jiffies(bfqd->last_ins_in_burst + + bfqd->bfq_burst_interval) || + bfqq->entity.parent != bfqd->burst_parent_entity) { + bfqd->large_burst = false; + bfq_reset_burst_list(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, + "handle_burst: late activation or different group"); + goto end; + } + + /* + * If we get here, then bfqq is being activated shortly after the + * last queue. So, if the current burst is also large, we can mark + * bfqq as belonging to this large burst immediately. + */ + if (bfqd->large_burst) { + bfq_log_bfqq(bfqd, bfqq, "handle_burst: marked in burst"); + bfq_mark_bfqq_in_large_burst(bfqq); + goto end; + } + + /* + * If we get here, then a large-burst state has not yet been + * reached, but bfqq is being activated shortly after the last + * queue. Then we add bfqq to the burst. + */ + bfq_add_to_burst(bfqd, bfqq); +end: + /* + * At this point, bfqq either has been added to the current + * burst or has caused the current burst to terminate and a + * possible new burst to start. In particular, in the second + * case, bfqq has become the first queue in the possible new + * burst. In both cases last_ins_in_burst needs to be moved + * forward. + */ + bfqd->last_ins_in_burst = jiffies; + +} + +static int bfq_bfqq_budget_left(struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + + return entity->budget - entity->service; +} + +/* + * If enough samples have been computed, return the current max budget + * stored in bfqd, which is dynamically updated according to the + * estimated disk peak rate; otherwise return the default max budget + */ +static int bfq_max_budget(struct bfq_data *bfqd) +{ + if (bfqd->budgets_assigned < bfq_stats_min_budgets) + return bfq_default_max_budget; + else + return bfqd->bfq_max_budget; +} + +/* + * Return min budget, which is a fraction of the current or default + * max budget (trying with 1/32) + */ +static int bfq_min_budget(struct bfq_data *bfqd) +{ + if (bfqd->budgets_assigned < bfq_stats_min_budgets) + return bfq_default_max_budget / 32; + else + return bfqd->bfq_max_budget / 32; +} + +static void bfq_bfqq_expire(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool compensate, + enum bfqq_expiration reason); + +/* + * The next function, invoked after the input queue bfqq switches from + * idle to busy, updates the budget of bfqq. The function also tells + * whether the in-service queue should be expired, by returning + * true. The purpose of expiring the in-service queue is to give bfqq + * the chance to possibly preempt the in-service queue, and the reason + * for preempting the in-service queue is to achieve one of the two + * goals below. + * + * 1. Guarantee to bfqq its reserved bandwidth even if bfqq has + * expired because it has remained idle. In particular, bfqq may have + * expired for one of the following two reasons: + * + * - BFQ_BFQQ_NO_MORE_REQUEST bfqq did not enjoy any device idling and + * did not make it to issue a new request before its last request + * was served; + * + * - BFQ_BFQQ_TOO_IDLE bfqq did enjoy device idling, but did not issue + * a new request before the expiration of the idling-time. + * + * Even if bfqq has expired for one of the above reasons, the process + * associated with the queue may be however issuing requests greedily, + * and thus be sensitive to the bandwidth it receives (bfqq may have + * remained idle for other reasons: CPU high load, bfqq not enjoying + * idling, I/O throttling somewhere in the path from the process to + * the I/O scheduler, ...). But if, after every expiration for one of + * the above two reasons, bfqq has to wait for the service of at least + * one full budget of another queue before being served again, then + * bfqq is likely to get a much lower bandwidth or resource time than + * its reserved ones. To address this issue, two countermeasures need + * to be taken. + * + * First, the budget and the timestamps of bfqq need to be updated in + * a special way on bfqq reactivation: they need to be updated as if + * bfqq did not remain idle and did not expire. In fact, if they are + * computed as if bfqq expired and remained idle until reactivation, + * then the process associated with bfqq is treated as if, instead of + * being greedy, it stopped issuing requests when bfqq remained idle, + * and restarts issuing requests only on this reactivation. In other + * words, the scheduler does not help the process recover the "service + * hole" between bfqq expiration and reactivation. As a consequence, + * the process receives a lower bandwidth than its reserved one. In + * contrast, to recover this hole, the budget must be updated as if + * bfqq was not expired at all before this reactivation, i.e., it must + * be set to the value of the remaining budget when bfqq was + * expired. Along the same line, timestamps need to be assigned the + * value they had the last time bfqq was selected for service, i.e., + * before last expiration. Thus timestamps need to be back-shifted + * with respect to their normal computation (see [1] for more details + * on this tricky aspect). + * + * Secondly, to allow the process to recover the hole, the in-service + * queue must be expired too, to give bfqq the chance to preempt it + * immediately. In fact, if bfqq has to wait for a full budget of the + * in-service queue to be completed, then it may become impossible to + * let the process recover the hole, even if the back-shifted + * timestamps of bfqq are lower than those of the in-service queue. If + * this happens for most or all of the holes, then the process may not + * receive its reserved bandwidth. In this respect, it is worth noting + * that, being the service of outstanding requests unpreemptible, a + * little fraction of the holes may however be unrecoverable, thereby + * causing a little loss of bandwidth. + * + * The last important point is detecting whether bfqq does need this + * bandwidth recovery. In this respect, the next function deems the + * process associated with bfqq greedy, and thus allows it to recover + * the hole, if: 1) the process is waiting for the arrival of a new + * request (which implies that bfqq expired for one of the above two + * reasons), and 2) such a request has arrived soon. The first + * condition is controlled through the flag non_blocking_wait_rq, + * while the second through the flag arrived_in_time. If both + * conditions hold, then the function computes the budget in the + * above-described special way, and signals that the in-service queue + * should be expired. Timestamp back-shifting is done later in + * __bfq_activate_entity. + * + * 2. Reduce latency. Even if timestamps are not backshifted to let + * the process associated with bfqq recover a service hole, bfqq may + * however happen to have, after being (re)activated, a lower finish + * timestamp than the in-service queue. That is, the next budget of + * bfqq may have to be completed before the one of the in-service + * queue. If this is the case, then preempting the in-service queue + * allows this goal to be achieved, apart from the unpreemptible, + * outstanding requests mentioned above. + * + * Unfortunately, regardless of which of the above two goals one wants + * to achieve, service trees need first to be updated to know whether + * the in-service queue must be preempted. To have service trees + * correctly updated, the in-service queue must be expired and + * rescheduled, and bfqq must be scheduled too. This is one of the + * most costly operations (in future versions, the scheduling + * mechanism may be re-designed in such a way to make it possible to + * know whether preemption is needed without needing to update service + * trees). In addition, queue preemptions almost always cause random + * I/O, and thus loss of throughput. Because of these facts, the next + * function adopts the following simple scheme to avoid both costly + * operations and too frequent preemptions: it requests the expiration + * of the in-service queue (unconditionally) only for queues that need + * to recover a hole, or that either are weight-raised or deserve to + * be weight-raised. + */ +static bool bfq_bfqq_update_budg_for_activation(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool arrived_in_time, + bool wr_or_deserves_wr) +{ + struct bfq_entity *entity = &bfqq->entity; + + if (bfq_bfqq_non_blocking_wait_rq(bfqq) && arrived_in_time) { + /* + * We do not clear the flag non_blocking_wait_rq here, as + * the latter is used in bfq_activate_bfqq to signal + * that timestamps need to be back-shifted (and is + * cleared right after). + */ + + /* + * In next assignment we rely on that either + * entity->service or entity->budget are not updated + * on expiration if bfqq is empty (see + * __bfq_bfqq_recalc_budget). Thus both quantities + * remain unchanged after such an expiration, and the + * following statement therefore assigns to + * entity->budget the remaining budget on such an + * expiration. For clarity, entity->service is not + * updated on expiration in any case, and, in normal + * operation, is reset only when bfqq is selected for + * service (see bfq_get_next_queue). + */ + BUG_ON(bfqq->max_budget < 0); + entity->budget = min_t(unsigned long, + bfq_bfqq_budget_left(bfqq), + bfqq->max_budget); + + BUG_ON(entity->budget < 0); + return true; + } + + BUG_ON(bfqq->max_budget < 0); + entity->budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(bfqq->next_rq, bfqq)); + BUG_ON(entity->budget < 0); + + bfq_clear_bfqq_non_blocking_wait_rq(bfqq); + return wr_or_deserves_wr; +} + +/* + * Return the farthest future time instant according to jiffies + * macros. + */ +static unsigned long bfq_greatest_from_now(void) +{ + return jiffies + MAX_JIFFY_OFFSET; +} + +/* + * Return the farthest past time instant according to jiffies + * macros. + */ +static unsigned long bfq_smallest_from_now(void) +{ + return jiffies - MAX_JIFFY_OFFSET; +} + +static void bfq_update_bfqq_wr_on_rq_arrival(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + unsigned int old_wr_coeff, + bool wr_or_deserves_wr, + bool interactive, + bool in_burst, + bool soft_rt) +{ + if (old_wr_coeff == 1 && wr_or_deserves_wr) { + /* start a weight-raising period */ + if (interactive) { + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + } else { + /* + * No interactive weight raising in progress + * here: assign minus infinity to + * wr_start_at_switch_to_srt, to make sure + * that, at the end of the soft-real-time + * weight raising periods that is starting + * now, no interactive weight-raising period + * may be wrongly considered as still in + * progress (and thus actually started by + * mistake). + */ + bfqq->wr_start_at_switch_to_srt = + bfq_smallest_from_now(); + bfqq->wr_coeff = bfqd->bfq_wr_coeff * + BFQ_SOFTRT_WEIGHT_FACTOR; + bfqq->wr_cur_max_time = + bfqd->bfq_wr_rt_max_time; + } + /* + * If needed, further reduce budget to make sure it is + * close to bfqq's backlog, so as to reduce the + * scheduling-error component due to a too large + * budget. Do not care about throughput consequences, + * but only about latency. Finally, do not assign a + * too small budget either, to avoid increasing + * latency by causing too frequent expirations. + */ + bfqq->entity.budget = min_t(unsigned long, + bfqq->entity.budget, + 2 * bfq_min_budget(bfqd)); + + bfq_log_bfqq(bfqd, bfqq, + "wrais starting at %lu, rais_max_time %u", + jiffies, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } else if (old_wr_coeff > 1) { + if (interactive) { /* update wr coeff and duration */ + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + } else if (in_burst) { + bfqq->wr_coeff = 1; + bfq_log_bfqq(bfqd, bfqq, + "wrais ending at %lu, rais_max_time %u", + jiffies, + jiffies_to_msecs(bfqq-> + wr_cur_max_time)); + } else if (soft_rt) { + /* + * The application is now or still meeting the + * requirements for being deemed soft rt. We + * can then correctly and safely (re)charge + * the weight-raising duration for the + * application with the weight-raising + * duration for soft rt applications. + * + * In particular, doing this recharge now, i.e., + * before the weight-raising period for the + * application finishes, reduces the probability + * of the following negative scenario: + * 1) the weight of a soft rt application is + * raised at startup (as for any newly + * created application), + * 2) since the application is not interactive, + * at a certain time weight-raising is + * stopped for the application, + * 3) at that time the application happens to + * still have pending requests, and hence + * is destined to not have a chance to be + * deemed soft rt before these requests are + * completed (see the comments to the + * function bfq_bfqq_softrt_next_start() + * for details on soft rt detection), + * 4) these pending requests experience a high + * latency because the application is not + * weight-raised while they are pending. + */ + if (bfqq->wr_cur_max_time != + bfqd->bfq_wr_rt_max_time) { + bfqq->wr_start_at_switch_to_srt = + bfqq->last_wr_start_finish; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); + + bfqq->wr_cur_max_time = + bfqd->bfq_wr_rt_max_time; + bfqq->wr_coeff = bfqd->bfq_wr_coeff * + BFQ_SOFTRT_WEIGHT_FACTOR; + bfq_log_bfqq(bfqd, bfqq, + "switching to soft_rt wr"); + } else + bfq_log_bfqq(bfqd, bfqq, + "moving forward soft_rt wr duration"); + bfqq->last_wr_start_finish = jiffies; + } + } +} + +static bool bfq_bfqq_idle_for_long_time(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + return bfqq->dispatched == 0 && + time_is_before_jiffies( + bfqq->budget_timeout + + bfqd->bfq_wr_min_idle_time); +} + +static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + int old_wr_coeff, + struct request *rq, + bool *interactive) +{ + bool soft_rt, in_burst, wr_or_deserves_wr, + bfqq_wants_to_preempt, + idle_for_long_time = bfq_bfqq_idle_for_long_time(bfqd, bfqq), + /* + * See the comments on + * bfq_bfqq_update_budg_for_activation for + * details on the usage of the next variable. + */ + arrived_in_time = ktime_get_ns() <= + bfqq->ttime.last_end_request + + bfqd->bfq_slice_idle * 3; + + bfq_log_bfqq(bfqd, bfqq, + "bfq_add_request non-busy: " + "jiffies %lu, in_time %d, idle_long %d busyw %d " + "wr_coeff %u", + jiffies, arrived_in_time, + idle_for_long_time, + bfq_bfqq_non_blocking_wait_rq(bfqq), + old_wr_coeff); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + BUG_ON(bfqq == bfqd->in_service_queue); + bfqg_stats_update_io_add(bfqq_group(RQ_BFQQ(rq)), bfqq, rq->cmd_flags); + + /* + * bfqq deserves to be weight-raised if: + * - it is sync, + * - it does not belong to a large burst, + * - it has been idle for enough time or is soft real-time, + * - is linked to a bfq_io_cq (it is not shared in any sense) + */ + in_burst = bfq_bfqq_in_large_burst(bfqq); + soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && + !in_burst && + time_is_before_jiffies(bfqq->soft_rt_next_start); + *interactive = + !in_burst && + idle_for_long_time; + wr_or_deserves_wr = bfqd->low_latency && + (bfqq->wr_coeff > 1 || + (bfq_bfqq_sync(bfqq) && + bfqq->bic && (*interactive || soft_rt))); + + bfq_log_bfqq(bfqd, bfqq, + "bfq_add_request: " + "in_burst %d, " + "soft_rt %d (next %lu), inter %d, bic %p", + bfq_bfqq_in_large_burst(bfqq), soft_rt, + bfqq->soft_rt_next_start, + *interactive, + bfqq->bic); + + /* + * Using the last flag, update budget and check whether bfqq + * may want to preempt the in-service queue. + */ + bfqq_wants_to_preempt = + bfq_bfqq_update_budg_for_activation(bfqd, bfqq, + arrived_in_time, + wr_or_deserves_wr); + + /* + * If bfqq happened to be activated in a burst, but has been + * idle for much more than an interactive queue, then we + * assume that, in the overall I/O initiated in the burst, the + * I/O associated with bfqq is finished. So bfqq does not need + * to be treated as a queue belonging to a burst + * anymore. Accordingly, we reset bfqq's in_large_burst flag + * if set, and remove bfqq from the burst list if it's + * there. We do not decrement burst_size, because the fact + * that bfqq does not need to belong to the burst list any + * more does not invalidate the fact that bfqq was created in + * a burst. + */ + if (likely(!bfq_bfqq_just_created(bfqq)) && + idle_for_long_time && + time_is_before_jiffies( + bfqq->budget_timeout + + msecs_to_jiffies(10000))) { + hlist_del_init(&bfqq->burst_list_node); + bfq_clear_bfqq_in_large_burst(bfqq); + } + + bfq_clear_bfqq_just_created(bfqq); + + if (!bfq_bfqq_IO_bound(bfqq)) { + if (arrived_in_time) { + bfqq->requests_within_timer++; + if (bfqq->requests_within_timer >= + bfqd->bfq_requests_within_timer) + bfq_mark_bfqq_IO_bound(bfqq); + } else + bfqq->requests_within_timer = 0; + bfq_log_bfqq(bfqd, bfqq, "requests in time %d", + bfqq->requests_within_timer); + } + + if (bfqd->low_latency) { + if (unlikely(time_is_after_jiffies(bfqq->split_time))) + /* wraparound */ + bfqq->split_time = + jiffies - bfqd->bfq_wr_min_idle_time - 1; + + if (time_is_before_jiffies(bfqq->split_time + + bfqd->bfq_wr_min_idle_time)) { + bfq_update_bfqq_wr_on_rq_arrival(bfqd, bfqq, + old_wr_coeff, + wr_or_deserves_wr, + *interactive, + in_burst, + soft_rt); + + if (old_wr_coeff != bfqq->wr_coeff) + bfqq->entity.prio_changed = 1; + } + } + + bfqq->last_idle_bklogged = jiffies; + bfqq->service_from_backlogged = 0; + bfq_clear_bfqq_softrt_update(bfqq); + + bfq_add_bfqq_busy(bfqd, bfqq); + + /* + * Expire in-service queue only if preemption may be needed + * for guarantees. In this respect, the function + * next_queue_may_preempt just checks a simple, necessary + * condition, and not a sufficient condition based on + * timestamps. In fact, for the latter condition to be + * evaluated, timestamps would need first to be updated, and + * this operation is quite costly (see the comments on the + * function bfq_bfqq_update_budg_for_activation). + */ + if (bfqd->in_service_queue && bfqq_wants_to_preempt && + bfqd->in_service_queue->wr_coeff < bfqq->wr_coeff && + next_queue_may_preempt(bfqd)) { + struct bfq_queue *in_serv = + bfqd->in_service_queue; + BUG_ON(in_serv == bfqq); + + bfq_bfqq_expire(bfqd, bfqd->in_service_queue, + false, BFQ_BFQQ_PREEMPTED); + } +} + +static void bfq_add_request(struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + struct bfq_data *bfqd = bfqq->bfqd; + struct request *next_rq, *prev; + unsigned int old_wr_coeff = bfqq->wr_coeff; + bool interactive = false; + + bfq_log_bfqq(bfqd, bfqq, "add_request: size %u %s", + blk_rq_sectors(rq), rq_is_sync(rq) ? "S" : "A"); + + if (bfqq->wr_coeff > 1) /* queue is being weight-raised */ + bfq_log_bfqq(bfqd, bfqq, + "raising period dur %u/%u msec, old coeff %u, w %d(%d)", + jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqq->wr_coeff, + bfqq->entity.weight, bfqq->entity.orig_weight); + + bfqq->queued[rq_is_sync(rq)]++; + bfqd->queued++; + + BUG_ON(!RQ_BFQQ(rq)); + BUG_ON(RQ_BFQQ(rq) != bfqq); + elv_rb_add(&bfqq->sort_list, rq); + + /* + * Check if this request is a better next-to-serve candidate. + */ + prev = bfqq->next_rq; + next_rq = bfq_choose_req(bfqd, bfqq->next_rq, rq, bfqd->last_position); + BUG_ON(!next_rq); + BUG_ON(!RQ_BFQQ(next_rq)); + BUG_ON(RQ_BFQQ(next_rq) != bfqq); + bfqq->next_rq = next_rq; + + /* + * Adjust priority tree position, if next_rq changes. + */ + if (prev != bfqq->next_rq) + bfq_pos_tree_add_move(bfqd, bfqq); + + if (!bfq_bfqq_busy(bfqq)) /* switching to busy ... */ + bfq_bfqq_handle_idle_busy_switch(bfqd, bfqq, old_wr_coeff, + rq, &interactive); + else { + if (bfqd->low_latency && old_wr_coeff == 1 && !rq_is_sync(rq) && + time_is_before_jiffies( + bfqq->last_wr_start_finish + + bfqd->bfq_wr_min_inter_arr_async)) { + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, bfqq, + "non-idle wrais starting, " + "wr_max_time %u wr_busy %d", + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqd->wr_busy_queues); + } + if (prev != bfqq->next_rq) + bfq_updated_next_req(bfqd, bfqq); + } + + /* + * Assign jiffies to last_wr_start_finish in the following + * cases: + * + * . if bfqq is not going to be weight-raised, because, for + * non weight-raised queues, last_wr_start_finish stores the + * arrival time of the last request; as of now, this piece + * of information is used only for deciding whether to + * weight-raise async queues + * + * . if bfqq is not weight-raised, because, if bfqq is now + * switching to weight-raised, then last_wr_start_finish + * stores the time when weight-raising starts + * + * . if bfqq is interactive, because, regardless of whether + * bfqq is currently weight-raised, the weight-raising + * period must start or restart (this case is considered + * separately because it is not detected by the above + * conditions, if bfqq is already weight-raised) + * + * last_wr_start_finish has to be updated also if bfqq is soft + * real-time, because the weight-raising period is constantly + * restarted on idle-to-busy transitions for these queues, but + * this is already done in bfq_bfqq_handle_idle_busy_switch if + * needed. + */ + if (bfqd->low_latency && + (old_wr_coeff == 1 || bfqq->wr_coeff == 1 || interactive)) + bfqq->last_wr_start_finish = jiffies; +} + +static struct request *bfq_find_rq_fmerge(struct bfq_data *bfqd, + struct bio *bio, + struct request_queue *q) +{ + struct bfq_queue *bfqq = bfqd->bio_bfqq; + + BUG_ON(!bfqd->bio_bfqq_set); + + if (bfqq) + return elv_rb_find(&bfqq->sort_list, bio_end_sector(bio)); + + return NULL; +} + +static sector_t get_sdist(sector_t last_pos, struct request *rq) +{ + sector_t sdist = 0; + + if (last_pos) { + if (last_pos < blk_rq_pos(rq)) + sdist = blk_rq_pos(rq) - last_pos; + else + sdist = last_pos - blk_rq_pos(rq); + } + + return sdist; +} + +#if 0 /* Still not clear if we can do without next two functions */ +static void bfq_activate_request(struct request_queue *q, struct request *rq) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + bfqd->rq_in_driver++; +} + +static void bfq_deactivate_request(struct request_queue *q, struct request *rq) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + + BUG_ON(bfqd->rq_in_driver == 0); + bfqd->rq_in_driver--; +} +#endif + +static void bfq_remove_request(struct request_queue *q, + struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + struct bfq_data *bfqd = bfqq->bfqd; + const int sync = rq_is_sync(rq); + + BUG_ON(bfqq->entity.service > bfqq->entity.budget && + bfqq == bfqd->in_service_queue); + + if (bfqq->next_rq == rq) { + bfqq->next_rq = bfq_find_next_rq(bfqd, bfqq, rq); + if (bfqq->next_rq && !RQ_BFQQ(bfqq->next_rq)) { + pr_crit("no bfqq! for next rq %p bfqq %p\n", + bfqq->next_rq, bfqq); + } + + BUG_ON(bfqq->next_rq && !RQ_BFQQ(bfqq->next_rq)); + if (bfqq->next_rq && RQ_BFQQ(bfqq->next_rq) != bfqq) { + pr_crit( + "wrong bfqq! for next rq %p, rq_bfqq %p bfqq %p\n", + bfqq->next_rq, RQ_BFQQ(bfqq->next_rq), bfqq); + } + BUG_ON(bfqq->next_rq && RQ_BFQQ(bfqq->next_rq) != bfqq); + + bfq_updated_next_req(bfqd, bfqq); + } + + if (rq->queuelist.prev != &rq->queuelist) + list_del_init(&rq->queuelist); + BUG_ON(bfqq->queued[sync] == 0); + bfqq->queued[sync]--; + bfqd->queued--; + elv_rb_del(&bfqq->sort_list, rq); + + elv_rqhash_del(q, rq); + if (q->last_merge == rq) + q->last_merge = NULL; + + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { + bfqq->next_rq = NULL; + + BUG_ON(bfqq->entity.budget < 0); + + if (bfq_bfqq_busy(bfqq) && bfqq != bfqd->in_service_queue) { + BUG_ON(bfqq->ref < 2); /* referred by rq and on tree */ + bfq_del_bfqq_busy(bfqd, bfqq, false); + /* + * bfqq emptied. In normal operation, when + * bfqq is empty, bfqq->entity.service and + * bfqq->entity.budget must contain, + * respectively, the service received and the + * budget used last time bfqq emptied. These + * facts do not hold in this case, as at least + * this last removal occurred while bfqq is + * not in service. To avoid inconsistencies, + * reset both bfqq->entity.service and + * bfqq->entity.budget, if bfqq has still a + * process that may issue I/O requests to it. + */ + bfqq->entity.budget = bfqq->entity.service = 0; + } + + /* + * Remove queue from request-position tree as it is empty. + */ + if (bfqq->pos_root) { + rb_erase(&bfqq->pos_node, bfqq->pos_root); + bfqq->pos_root = NULL; + } + } + + if (rq->cmd_flags & REQ_META) { + BUG_ON(bfqq->meta_pending == 0); + bfqq->meta_pending--; + } + bfqg_stats_update_io_remove(bfqq_group(bfqq), rq->cmd_flags); +} + +static bool bfq_bio_merge(struct blk_mq_hw_ctx *hctx, struct bio *bio) +{ + struct request_queue *q = hctx->queue; + struct bfq_data *bfqd = q->elevator->elevator_data; + struct request *free = NULL; + /* + * bfq_bic_lookup grabs the queue_lock: invoke it now and + * store its return value for later use, to avoid nesting + * queue_lock inside the bfqd->lock. We assume that the bic + * returned by bfq_bic_lookup does not go away before + * bfqd->lock is taken. + */ + struct bfq_io_cq *bic = bfq_bic_lookup(bfqd, current->io_context, q); + bool ret; + + spin_lock_irq(&bfqd->lock); + + if (bic) + bfqd->bio_bfqq = bic_to_bfqq(bic, op_is_sync(bio->bi_opf)); + else + bfqd->bio_bfqq = NULL; + bfqd->bio_bic = bic; + /* Set next flag just for testing purposes */ + bfqd->bio_bfqq_set = true; + + ret = blk_mq_sched_try_merge(q, bio, &free); + + /* + * XXX Not yet freeing without lock held, to avoid an + * inconsistency with respect to the lock-protected invocation + * of blk_mq_sched_try_insert_merge in bfq_bio_merge. Waiting + * for clarifications from Jens. + */ + if (free) + blk_mq_free_request(free); + bfqd->bio_bfqq_set = false; + spin_unlock_irq(&bfqd->lock); + + return ret; +} + +static int bfq_request_merge(struct request_queue *q, struct request **req, + struct bio *bio) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct request *__rq; + + __rq = bfq_find_rq_fmerge(bfqd, bio, q); + if (__rq && elv_bio_merge_ok(__rq, bio)) { + *req = __rq; + bfq_log(bfqd, "request_merge: req %p", __rq); + + return ELEVATOR_FRONT_MERGE; + } + + return ELEVATOR_NO_MERGE; +} + +static void bfq_request_merged(struct request_queue *q, struct request *req, + enum elv_merge type) +{ + BUG_ON(req->rq_flags & RQF_DISP_LIST); + + if (type == ELEVATOR_FRONT_MERGE && + rb_prev(&req->rb_node) && + blk_rq_pos(req) < + blk_rq_pos(container_of(rb_prev(&req->rb_node), + struct request, rb_node))) { + struct bfq_queue *bfqq = RQ_BFQQ(req); + struct bfq_data *bfqd = bfqq->bfqd; + struct request *prev, *next_rq; + + /* Reposition request in its sort_list */ + elv_rb_del(&bfqq->sort_list, req); + BUG_ON(!RQ_BFQQ(req)); + BUG_ON(RQ_BFQQ(req) != bfqq); + elv_rb_add(&bfqq->sort_list, req); + + /* Choose next request to be served for bfqq */ + prev = bfqq->next_rq; + next_rq = bfq_choose_req(bfqd, bfqq->next_rq, req, + bfqd->last_position); + BUG_ON(!next_rq); + + bfqq->next_rq = next_rq; + + bfq_log_bfqq(bfqd, bfqq, + "requests_merged: req %p prev %p next_rq %p bfqq %p", + req, prev, next_rq, bfqq); + + /* + * If next_rq changes, update both the queue's budget to + * fit the new request and the queue's position in its + * rq_pos_tree. + */ + if (prev != bfqq->next_rq) { + bfq_updated_next_req(bfqd, bfqq); + bfq_pos_tree_add_move(bfqd, bfqq); + } + } +} + +static void bfq_requests_merged(struct request_queue *q, struct request *rq, + struct request *next) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq), *next_bfqq = RQ_BFQQ(next); + + BUG_ON(!RQ_BFQQ(rq)); + BUG_ON(!RQ_BFQQ(next)); + BUG_ON(rq->rq_flags & RQF_DISP_LIST); + BUG_ON(next->rq_flags & RQF_DISP_LIST); + + if (!RB_EMPTY_NODE(&rq->rb_node)) + goto end; + + bfq_log_bfqq(bfqq->bfqd, bfqq, + "requests_merged: rq %p next %p bfqq %p next_bfqq %p", + rq, next, bfqq, next_bfqq); + + spin_lock_irq(&bfqq->bfqd->lock); + + /* + * If next and rq belong to the same bfq_queue and next is older + * than rq, then reposition rq in the fifo (by substituting next + * with rq). Otherwise, if next and rq belong to different + * bfq_queues, never reposition rq: in fact, we would have to + * reposition it with respect to next's position in its own fifo, + * which would most certainly be too expensive with respect to + * the benefits. + */ + if (bfqq == next_bfqq && + !list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && + next->fifo_time < rq->fifo_time) { + list_del_init(&rq->queuelist); + list_replace_init(&next->queuelist, &rq->queuelist); + rq->fifo_time = next->fifo_time; + } + + if (bfqq->next_rq == next) + bfqq->next_rq = rq; + + bfq_remove_request(q, next); + + spin_unlock_irq(&bfqq->bfqd->lock); +end: + bfqg_stats_update_io_merged(bfqq_group(bfqq), next->cmd_flags); +} + +/* Must be called with bfqq != NULL */ +static void bfq_bfqq_end_wr(struct bfq_queue *bfqq) +{ + BUG_ON(!bfqq); + + if (bfq_bfqq_busy(bfqq)) { + bfqq->bfqd->wr_busy_queues--; + BUG_ON(bfqq->bfqd->wr_busy_queues < 0); + } + bfqq->wr_coeff = 1; + bfqq->wr_cur_max_time = 0; + bfqq->last_wr_start_finish = jiffies; + /* + * Trigger a weight change on the next invocation of + * __bfq_entity_update_weight_prio. + */ + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "end_wr: wrais ending at %lu, rais_max_time %u", + bfqq->last_wr_start_finish, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + bfq_log_bfqq(bfqq->bfqd, bfqq, "end_wr: wr_busy %d", + bfqq->bfqd->wr_busy_queues); +} + +static void bfq_end_wr_async_queues(struct bfq_data *bfqd, + struct bfq_group *bfqg) +{ + int i, j; + + for (i = 0; i < 2; i++) + for (j = 0; j < IOPRIO_BE_NR; j++) + if (bfqg->async_bfqq[i][j]) + bfq_bfqq_end_wr(bfqg->async_bfqq[i][j]); + if (bfqg->async_idle_bfqq) + bfq_bfqq_end_wr(bfqg->async_idle_bfqq); +} + +static void bfq_end_wr(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq; + + spin_lock_irq(&bfqd->lock); + + list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) + bfq_bfqq_end_wr(bfqq); + list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) + bfq_bfqq_end_wr(bfqq); + bfq_end_wr_async(bfqd); + + spin_unlock_irq(&bfqd->lock); +} + +static sector_t bfq_io_struct_pos(void *io_struct, bool request) +{ + if (request) + return blk_rq_pos(io_struct); + else + return ((struct bio *)io_struct)->bi_iter.bi_sector; +} + +static int bfq_rq_close_to_sector(void *io_struct, bool request, + sector_t sector) +{ + return abs(bfq_io_struct_pos(io_struct, request) - sector) <= + BFQQ_CLOSE_THR; +} + +static struct bfq_queue *bfqq_find_close(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + sector_t sector) +{ + struct rb_root *root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; + struct rb_node *parent, *node; + struct bfq_queue *__bfqq; + + if (RB_EMPTY_ROOT(root)) + return NULL; + + /* + * First, if we find a request starting at the end of the last + * request, choose it. + */ + __bfqq = bfq_rq_pos_tree_lookup(bfqd, root, sector, &parent, NULL); + if (__bfqq) + return __bfqq; + + /* + * If the exact sector wasn't found, the parent of the NULL leaf + * will contain the closest sector (rq_pos_tree sorted by + * next_request position). + */ + __bfqq = rb_entry(parent, struct bfq_queue, pos_node); + if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) + return __bfqq; + + if (blk_rq_pos(__bfqq->next_rq) < sector) + node = rb_next(&__bfqq->pos_node); + else + node = rb_prev(&__bfqq->pos_node); + if (!node) + return NULL; + + __bfqq = rb_entry(node, struct bfq_queue, pos_node); + if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) + return __bfqq; + + return NULL; +} + +static struct bfq_queue *bfq_find_close_cooperator(struct bfq_data *bfqd, + struct bfq_queue *cur_bfqq, + sector_t sector) +{ + struct bfq_queue *bfqq; + + /* + * We shall notice if some of the queues are cooperating, + * e.g., working closely on the same area of the device. In + * that case, we can group them together and: 1) don't waste + * time idling, and 2) serve the union of their requests in + * the best possible order for throughput. + */ + bfqq = bfqq_find_close(bfqd, cur_bfqq, sector); + if (!bfqq || bfqq == cur_bfqq) + return NULL; + + return bfqq; +} + +static struct bfq_queue * +bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +{ + int process_refs, new_process_refs; + struct bfq_queue *__bfqq; + + /* + * If there are no process references on the new_bfqq, then it is + * unsafe to follow the ->new_bfqq chain as other bfqq's in the chain + * may have dropped their last reference (not just their last process + * reference). + */ + if (!bfqq_process_refs(new_bfqq)) + return NULL; + + /* Avoid a circular list and skip interim queue merges. */ + while ((__bfqq = new_bfqq->new_bfqq)) { + if (__bfqq == bfqq) + return NULL; + new_bfqq = __bfqq; + } + + process_refs = bfqq_process_refs(bfqq); + new_process_refs = bfqq_process_refs(new_bfqq); + /* + * If the process for the bfqq has gone away, there is no + * sense in merging the queues. + */ + if (process_refs == 0 || new_process_refs == 0) + return NULL; + + bfq_log_bfqq(bfqq->bfqd, bfqq, "scheduling merge with queue %d", + new_bfqq->pid); + + /* + * Merging is just a redirection: the requests of the process + * owning one of the two queues are redirected to the other queue. + * The latter queue, in its turn, is set as shared if this is the + * first time that the requests of some process are redirected to + * it. + * + * We redirect bfqq to new_bfqq and not the opposite, because + * we are in the context of the process owning bfqq, thus we + * have the io_cq of this process. So we can immediately + * configure this io_cq to redirect the requests of the + * process to new_bfqq. In contrast, the io_cq of new_bfqq is + * not available any more (new_bfqq->bic == NULL). + * + * Anyway, even in case new_bfqq coincides with the in-service + * queue, redirecting requests the in-service queue is the + * best option, as we feed the in-service queue with new + * requests close to the last request served and, by doing so, + * are likely to increase the throughput. + */ + bfqq->new_bfqq = new_bfqq; + new_bfqq->ref += process_refs; + return new_bfqq; +} + +static bool bfq_may_be_close_cooperator(struct bfq_queue *bfqq, + struct bfq_queue *new_bfqq) +{ + if (bfq_class_idle(bfqq) || bfq_class_idle(new_bfqq) || + (bfqq->ioprio_class != new_bfqq->ioprio_class)) + return false; + + /* + * If either of the queues has already been detected as seeky, + * then merging it with the other queue is unlikely to lead to + * sequential I/O. + */ + if (BFQQ_SEEKY(bfqq) || BFQQ_SEEKY(new_bfqq)) + return false; + + /* + * Interleaved I/O is known to be done by (some) applications + * only for reads, so it does not make sense to merge async + * queues. + */ + if (!bfq_bfqq_sync(bfqq) || !bfq_bfqq_sync(new_bfqq)) + return false; + + return true; +} + +/* + * If this function returns true, then bfqq cannot be merged. The idea + * is that true cooperation happens very early after processes start + * to do I/O. Usually, late cooperations are just accidental false + * positives. In case bfqq is weight-raised, such false positives + * would evidently degrade latency guarantees for bfqq. + */ +static bool wr_from_too_long(struct bfq_queue *bfqq) +{ + return bfqq->wr_coeff > 1 && + time_is_before_jiffies(bfqq->last_wr_start_finish + + msecs_to_jiffies(100)); +} + +/* + * Attempt to schedule a merge of bfqq with the currently in-service + * queue or with a close queue among the scheduled queues. Return + * NULL if no merge was scheduled, a pointer to the shared bfq_queue + * structure otherwise. + * + * The OOM queue is not allowed to participate to cooperation: in fact, since + * the requests temporarily redirected to the OOM queue could be redirected + * again to dedicated queues at any time, the state needed to correctly + * handle merging with the OOM queue would be quite complex and expensive + * to maintain. Besides, in such a critical condition as an out of memory, + * the benefits of queue merging may be little relevant, or even negligible. + * + * Weight-raised queues can be merged only if their weight-raising + * period has just started. In fact cooperating processes are usually + * started together. Thus, with this filter we avoid false positives + * that would jeopardize low-latency guarantees. + * + * WARNING: queue merging may impair fairness among non-weight raised + * queues, for at least two reasons: 1) the original weight of a + * merged queue may change during the merged state, 2) even being the + * weight the same, a merged queue may be bloated with many more + * requests than the ones produced by its originally-associated + * process. + */ +static struct bfq_queue * +bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, + void *io_struct, bool request) +{ + struct bfq_queue *in_service_bfqq, *new_bfqq; + + if (bfqq->new_bfqq) + return bfqq->new_bfqq; + + if (io_struct && wr_from_too_long(bfqq) && + likely(bfqq != &bfqd->oom_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have looked for coop, but bfq%d wr", + bfqq->pid); + + if (!io_struct || + wr_from_too_long(bfqq) || + unlikely(bfqq == &bfqd->oom_bfqq)) + return NULL; + + /* If there is only one backlogged queue, don't search. */ + if (bfqd->busy_queues == 1) + return NULL; + + in_service_bfqq = bfqd->in_service_queue; + + if (in_service_bfqq && in_service_bfqq != bfqq && + wr_from_too_long(in_service_bfqq) + && likely(in_service_bfqq == &bfqd->oom_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have tried merge with in-service-queue, but wr"); + + if (!in_service_bfqq || in_service_bfqq == bfqq + || wr_from_too_long(in_service_bfqq) || + unlikely(in_service_bfqq == &bfqd->oom_bfqq)) + goto check_scheduled; + + if (bfq_rq_close_to_sector(io_struct, request, bfqd->last_position) && + bfqq->entity.parent == in_service_bfqq->entity.parent && + bfq_may_be_close_cooperator(bfqq, in_service_bfqq)) { + new_bfqq = bfq_setup_merge(bfqq, in_service_bfqq); + if (new_bfqq) + return new_bfqq; + } + /* + * Check whether there is a cooperator among currently scheduled + * queues. The only thing we need is that the bio/request is not + * NULL, as we need it to establish whether a cooperator exists. + */ +check_scheduled: + new_bfqq = bfq_find_close_cooperator(bfqd, bfqq, + bfq_io_struct_pos(io_struct, request)); + + BUG_ON(new_bfqq && bfqq->entity.parent != new_bfqq->entity.parent); + + if (new_bfqq && wr_from_too_long(new_bfqq) && + likely(new_bfqq != &bfqd->oom_bfqq) && + bfq_may_be_close_cooperator(bfqq, new_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have merged with bfq%d, but wr", + new_bfqq->pid); + + if (new_bfqq && !wr_from_too_long(new_bfqq) && + likely(new_bfqq != &bfqd->oom_bfqq) && + bfq_may_be_close_cooperator(bfqq, new_bfqq)) + return bfq_setup_merge(bfqq, new_bfqq); + + return NULL; +} + +static void bfq_bfqq_save_state(struct bfq_queue *bfqq) +{ + struct bfq_io_cq *bic = bfqq->bic; + + /* + * If !bfqq->bic, the queue is already shared or its requests + * have already been redirected to a shared queue; both idle window + * and weight raising state have already been saved. Do nothing. + */ + if (!bic) + return; + + bic->saved_ttime = bfqq->ttime; + bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq); + bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq); + bic->saved_in_large_burst = bfq_bfqq_in_large_burst(bfqq); + bic->was_in_burst_list = !hlist_unhashed(&bfqq->burst_list_node); + bic->saved_wr_coeff = bfqq->wr_coeff; + bic->saved_wr_start_at_switch_to_srt = bfqq->wr_start_at_switch_to_srt; + bic->saved_last_wr_start_finish = bfqq->last_wr_start_finish; + bic->saved_wr_cur_max_time = bfqq->wr_cur_max_time; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); +} + +static void +bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, + struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +{ + bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", + (unsigned long) new_bfqq->pid); + BUG_ON(bfqq->bic && bfqq->bic == new_bfqq->bic); + /* Save weight raising and idle window of the merged queues */ + bfq_bfqq_save_state(bfqq); + bfq_bfqq_save_state(new_bfqq); + + if (bfq_bfqq_IO_bound(bfqq)) + bfq_mark_bfqq_IO_bound(new_bfqq); + bfq_clear_bfqq_IO_bound(bfqq); + + /* + * If bfqq is weight-raised, then let new_bfqq inherit + * weight-raising. To reduce false positives, neglect the case + * where bfqq has just been created, but has not yet made it + * to be weight-raised (which may happen because EQM may merge + * bfqq even before bfq_add_request is executed for the first + * time for bfqq). Handling this case would however be very + * easy, thanks to the flag just_created. + */ + if (new_bfqq->wr_coeff == 1 && bfqq->wr_coeff > 1) { + new_bfqq->wr_coeff = bfqq->wr_coeff; + new_bfqq->wr_cur_max_time = bfqq->wr_cur_max_time; + new_bfqq->last_wr_start_finish = bfqq->last_wr_start_finish; + new_bfqq->wr_start_at_switch_to_srt = + bfqq->wr_start_at_switch_to_srt; + if (bfq_bfqq_busy(new_bfqq)) { + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + } + + new_bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, new_bfqq, + "wr start after merge with %d, rais_max_time %u", + bfqq->pid, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + if (bfqq->wr_coeff > 1) { /* bfqq has given its wr to new_bfqq */ + bfqq->wr_coeff = 1; + bfqq->entity.prio_changed = 1; + if (bfq_bfqq_busy(bfqq)) { + bfqd->wr_busy_queues--; + BUG_ON(bfqd->wr_busy_queues < 0); + } + + } + + bfq_log_bfqq(bfqd, new_bfqq, "merge_bfqqs: wr_busy %d", + bfqd->wr_busy_queues); + + /* + * Merge queues (that is, let bic redirect its requests to new_bfqq) + */ + bic_set_bfqq(bic, new_bfqq, 1); + bfq_mark_bfqq_coop(new_bfqq); + /* + * new_bfqq now belongs to at least two bics (it is a shared queue): + * set new_bfqq->bic to NULL. bfqq either: + * - does not belong to any bic any more, and hence bfqq->bic must + * be set to NULL, or + * - is a queue whose owning bics have already been redirected to a + * different queue, hence the queue is destined to not belong to + * any bic soon and bfqq->bic is already NULL (therefore the next + * assignment causes no harm). + */ + new_bfqq->bic = NULL; + bfqq->bic = NULL; + /* release process reference to bfqq */ + bfq_put_queue(bfqq); +} + +static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq, + struct bio *bio) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + bool is_sync = op_is_sync(bio->bi_opf); + struct bfq_queue *bfqq = bfqd->bio_bfqq, *new_bfqq; + + assert_spin_locked(&bfqd->lock); + /* + * Disallow merge of a sync bio into an async request. + */ + if (is_sync && !rq_is_sync(rq)) + return false; + + /* + * Lookup the bfqq that this bio will be queued with. Allow + * merge only if rq is queued there. + */ + BUG_ON(!bfqd->bio_bfqq_set); + if (!bfqq) + return false; + + /* + * We take advantage of this function to perform an early merge + * of the queues of possible cooperating processes. + */ + new_bfqq = bfq_setup_cooperator(bfqd, bfqq, bio, false); + BUG_ON(new_bfqq == bfqq); + if (new_bfqq) { + /* + * bic still points to bfqq, then it has not yet been + * redirected to some other bfq_queue, and a queue + * merge beween bfqq and new_bfqq can be safely + * fulfillled, i.e., bic can be redirected to new_bfqq + * and bfqq can be put. + */ + bfq_merge_bfqqs(bfqd, bfqd->bio_bic, bfqq, + new_bfqq); + /* + * If we get here, bio will be queued into new_queue, + * so use new_bfqq to decide whether bio and rq can be + * merged. + */ + bfqq = new_bfqq; + + /* + * Change also bqfd->bio_bfqq, as + * bfqd->bio_bic now points to new_bfqq, and + * this function may be invoked again (and then may + * use again bqfd->bio_bfqq). + */ + bfqd->bio_bfqq = bfqq; + } + return bfqq == RQ_BFQQ(rq); +} + +/* + * Set the maximum time for the in-service queue to consume its + * budget. This prevents seeky processes from lowering the throughput. + * In practice, a time-slice service scheme is used with seeky + * processes. + */ +static void bfq_set_budget_timeout(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + unsigned int timeout_coeff; + + if (bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time) + timeout_coeff = 1; + else + timeout_coeff = bfqq->entity.weight / bfqq->entity.orig_weight; + + bfqd->last_budget_start = ktime_get(); + + bfqq->budget_timeout = jiffies + + bfqd->bfq_timeout * timeout_coeff; + + bfq_log_bfqq(bfqd, bfqq, "set budget_timeout %u", + jiffies_to_msecs(bfqd->bfq_timeout * timeout_coeff)); +} + +static void __bfq_set_in_service_queue(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + if (bfqq) { + bfqg_stats_update_avg_queue_size(bfqq_group(bfqq)); + bfq_clear_bfqq_fifo_expire(bfqq); + + bfqd->budgets_assigned = (bfqd->budgets_assigned*7 + 256) / 8; + + BUG_ON(bfqq == bfqd->in_service_queue); + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + + if (time_is_before_jiffies(bfqq->last_wr_start_finish) && + bfqq->wr_coeff > 1 && + bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + time_is_before_jiffies(bfqq->budget_timeout)) { + /* + * For soft real-time queues, move the start + * of the weight-raising period forward by the + * time the queue has not received any + * service. Otherwise, a relatively long + * service delay is likely to cause the + * weight-raising period of the queue to end, + * because of the short duration of the + * weight-raising period of a soft real-time + * queue. It is worth noting that this move + * is not so dangerous for the other queues, + * because soft real-time queues are not + * greedy. + * + * To not add a further variable, we use the + * overloaded field budget_timeout to + * determine for how long the queue has not + * received service, i.e., how much time has + * elapsed since the queue expired. However, + * this is a little imprecise, because + * budget_timeout is set to jiffies if bfqq + * not only expires, but also remains with no + * request. + */ + if (time_after(bfqq->budget_timeout, + bfqq->last_wr_start_finish)) + bfqq->last_wr_start_finish += + jiffies - bfqq->budget_timeout; + else + bfqq->last_wr_start_finish = jiffies; + + if (time_is_after_jiffies(bfqq->last_wr_start_finish)) { + pr_crit( + "BFQ WARNING:last %lu budget %lu jiffies %lu", + bfqq->last_wr_start_finish, + bfqq->budget_timeout, + jiffies); + pr_crit("diff %lu", jiffies - + max_t(unsigned long, + bfqq->last_wr_start_finish, + bfqq->budget_timeout)); + bfqq->last_wr_start_finish = jiffies; + } + } + + bfq_set_budget_timeout(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, + "set_in_service_queue, cur-budget = %d", + bfqq->entity.budget); + } else + bfq_log(bfqd, "set_in_service_queue: NULL"); + + bfqd->in_service_queue = bfqq; +} + +/* + * Get and set a new queue for service. + */ +static struct bfq_queue *bfq_set_in_service_queue(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq = bfq_get_next_queue(bfqd); + + __bfq_set_in_service_queue(bfqd, bfqq); + return bfqq; +} + +static void bfq_arm_slice_timer(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq = bfqd->in_service_queue; + u32 sl; + + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); + + bfq_mark_bfqq_wait_request(bfqq); + + /* + * We don't want to idle for seeks, but we do want to allow + * fair distribution of slice time for a process doing back-to-back + * seeks. So allow a little bit of time for him to submit a new rq. + * + * To prevent processes with (partly) seeky workloads from + * being too ill-treated, grant them a small fraction of the + * assigned budget before reducing the waiting time to + * BFQ_MIN_TT. This happened to help reduce latency. + */ + sl = bfqd->bfq_slice_idle; + /* + * Unless the queue is being weight-raised or the scenario is + * asymmetric, grant only minimum idle time if the queue + * is seeky. A long idling is preserved for a weight-raised + * queue, or, more in general, in an asymemtric scenario, + * because a long idling is needed for guaranteeing to a queue + * its reserved share of the throughput (in particular, it is + * needed if the queue has a higher weight than some other + * queue). + */ + if (BFQQ_SEEKY(bfqq) && bfqq->wr_coeff == 1 && + bfq_symmetric_scenario(bfqd)) + sl = min_t(u32, sl, BFQ_MIN_TT); + + bfqd->last_idling_start = ktime_get(); + hrtimer_start(&bfqd->idle_slice_timer, ns_to_ktime(sl), + HRTIMER_MODE_REL); + bfqg_stats_set_start_idle_time(bfqq_group(bfqq)); + bfq_log(bfqd, "arm idle: %ld/%ld ms", + sl / NSEC_PER_MSEC, bfqd->bfq_slice_idle / NSEC_PER_MSEC); +} + +/* + * In autotuning mode, max_budget is dynamically recomputed as the + * amount of sectors transferred in timeout at the estimated peak + * rate. This enables BFQ to utilize a full timeslice with a full + * budget, even if the in-service queue is served at peak rate. And + * this maximises throughput with sequential workloads. + */ +static unsigned long bfq_calc_max_budget(struct bfq_data *bfqd) +{ + return (u64)bfqd->peak_rate * USEC_PER_MSEC * + jiffies_to_msecs(bfqd->bfq_timeout)>>BFQ_RATE_SHIFT; +} + +/* + * Update parameters related to throughput and responsiveness, as a + * function of the estimated peak rate. See comments on + * bfq_calc_max_budget(), and on T_slow and T_fast arrays. + */ +static void update_thr_responsiveness_params(struct bfq_data *bfqd) +{ + int dev_type = blk_queue_nonrot(bfqd->queue); + + if (bfqd->bfq_user_max_budget == 0) { + bfqd->bfq_max_budget = + bfq_calc_max_budget(bfqd); + BUG_ON(bfqd->bfq_max_budget < 0); + bfq_log(bfqd, "new max_budget = %d", + bfqd->bfq_max_budget); + } + + if (bfqd->device_speed == BFQ_BFQD_FAST && + bfqd->peak_rate < device_speed_thresh[dev_type]) { + bfqd->device_speed = BFQ_BFQD_SLOW; + bfqd->RT_prod = R_slow[dev_type] * + T_slow[dev_type]; + } else if (bfqd->device_speed == BFQ_BFQD_SLOW && + bfqd->peak_rate > device_speed_thresh[dev_type]) { + bfqd->device_speed = BFQ_BFQD_FAST; + bfqd->RT_prod = R_fast[dev_type] * + T_fast[dev_type]; + } + + bfq_log(bfqd, +"dev_type %s dev_speed_class = %s (%llu sects/sec), thresh %llu setcs/sec", + dev_type == 0 ? "ROT" : "NONROT", + bfqd->device_speed == BFQ_BFQD_FAST ? "FAST" : "SLOW", + bfqd->device_speed == BFQ_BFQD_FAST ? + (USEC_PER_SEC*(u64)R_fast[dev_type])>>BFQ_RATE_SHIFT : + (USEC_PER_SEC*(u64)R_slow[dev_type])>>BFQ_RATE_SHIFT, + (USEC_PER_SEC*(u64)device_speed_thresh[dev_type])>> + BFQ_RATE_SHIFT); +} + +static void bfq_reset_rate_computation(struct bfq_data *bfqd, struct request *rq) +{ + if (rq != NULL) { /* new rq dispatch now, reset accordingly */ + bfqd->last_dispatch = bfqd->first_dispatch = ktime_get_ns() ; + bfqd->peak_rate_samples = 1; + bfqd->sequential_samples = 0; + bfqd->tot_sectors_dispatched = bfqd->last_rq_max_size = + blk_rq_sectors(rq); + } else /* no new rq dispatched, just reset the number of samples */ + bfqd->peak_rate_samples = 0; /* full re-init on next disp. */ + + bfq_log(bfqd, + "reset_rate_computation at end, sample %u/%u tot_sects %llu", + bfqd->peak_rate_samples, bfqd->sequential_samples, + bfqd->tot_sectors_dispatched); +} + +static void bfq_update_rate_reset(struct bfq_data *bfqd, struct request *rq) +{ + u32 rate, weight, divisor; + + /* + * For the convergence property to hold (see comments on + * bfq_update_peak_rate()) and for the assessment to be + * reliable, a minimum number of samples must be present, and + * a minimum amount of time must have elapsed. If not so, do + * not compute new rate. Just reset parameters, to get ready + * for a new evaluation attempt. + */ + if (bfqd->peak_rate_samples < BFQ_RATE_MIN_SAMPLES || + bfqd->delta_from_first < BFQ_RATE_MIN_INTERVAL) { + bfq_log(bfqd, + "update_rate_reset: only resetting, delta_first %lluus samples %d", + bfqd->delta_from_first>>10, bfqd->peak_rate_samples); + goto reset_computation; + } + + /* + * If a new request completion has occurred after last + * dispatch, then, to approximate the rate at which requests + * have been served by the device, it is more precise to + * extend the observation interval to the last completion. + */ + bfqd->delta_from_first = + max_t(u64, bfqd->delta_from_first, + bfqd->last_completion - bfqd->first_dispatch); + + BUG_ON(bfqd->delta_from_first == 0); + /* + * Rate computed in sects/usec, and not sects/nsec, for + * precision issues. + */ + rate = div64_ul(bfqd->tot_sectors_dispatched<delta_from_first, NSEC_PER_USEC)); + + bfq_log(bfqd, +"update_rate_reset: tot_sects %llu delta_first %lluus rate %llu sects/s (%d)", + bfqd->tot_sectors_dispatched, bfqd->delta_from_first>>10, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + rate > 20< 20M sectors/sec) + */ + if ((bfqd->sequential_samples < (3 * bfqd->peak_rate_samples)>>2 && + rate <= bfqd->peak_rate) || + rate > 20<peak_rate_samples, bfqd->sequential_samples, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + goto reset_computation; + } else { + bfq_log(bfqd, + "update_rate_reset: do update, samples %u/%u rate/peak %llu/%llu", + bfqd->peak_rate_samples, bfqd->sequential_samples, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + } + + /* + * We have to update the peak rate, at last! To this purpose, + * we use a low-pass filter. We compute the smoothing constant + * of the filter as a function of the 'weight' of the new + * measured rate. + * + * As can be seen in next formulas, we define this weight as a + * quantity proportional to how sequential the workload is, + * and to how long the observation time interval is. + * + * The weight runs from 0 to 8. The maximum value of the + * weight, 8, yields the minimum value for the smoothing + * constant. At this minimum value for the smoothing constant, + * the measured rate contributes for half of the next value of + * the estimated peak rate. + * + * So, the first step is to compute the weight as a function + * of how sequential the workload is. Note that the weight + * cannot reach 9, because bfqd->sequential_samples cannot + * become equal to bfqd->peak_rate_samples, which, in its + * turn, holds true because bfqd->sequential_samples is not + * incremented for the first sample. + */ + weight = (9 * bfqd->sequential_samples) / bfqd->peak_rate_samples; + + /* + * Second step: further refine the weight as a function of the + * duration of the observation interval. + */ + weight = min_t(u32, 8, + div_u64(weight * bfqd->delta_from_first, + BFQ_RATE_REF_INTERVAL)); + + /* + * Divisor ranging from 10, for minimum weight, to 2, for + * maximum weight. + */ + divisor = 10 - weight; + BUG_ON(divisor == 0); + + /* + * Finally, update peak rate: + * + * peak_rate = peak_rate * (divisor-1) / divisor + rate / divisor + */ + bfqd->peak_rate *= divisor-1; + bfqd->peak_rate /= divisor; + rate /= divisor; /* smoothing constant alpha = 1/divisor */ + + bfq_log(bfqd, + "update_rate_reset: divisor %d tmp_peak_rate %llu tmp_rate %u", + divisor, + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT), + (u32)((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT)); + + BUG_ON(bfqd->peak_rate == 0); + BUG_ON(bfqd->peak_rate > 20<peak_rate += rate; + update_thr_responsiveness_params(bfqd); + BUG_ON(bfqd->peak_rate > 20<peak_rate_samples == 0) { /* first dispatch */ + bfq_log(bfqd, + "update_peak_rate: goto reset, samples %d", + bfqd->peak_rate_samples) ; + bfq_reset_rate_computation(bfqd, rq); + goto update_last_values; /* will add one sample */ + } + + /* + * Device idle for very long: the observation interval lasting + * up to this dispatch cannot be a valid observation interval + * for computing a new peak rate (similarly to the late- + * completion event in bfq_completed_request()). Go to + * update_rate_and_reset to have the following three steps + * taken: + * - close the observation interval at the last (previous) + * request dispatch or completion + * - compute rate, if possible, for that observation interval + * - start a new observation interval with this dispatch + */ + if (now_ns - bfqd->last_dispatch > 100*NSEC_PER_MSEC && + bfqd->rq_in_driver == 0) { + bfq_log(bfqd, +"update_peak_rate: jumping to updating&resetting delta_last %lluus samples %d", + (now_ns - bfqd->last_dispatch)>>10, + bfqd->peak_rate_samples) ; + goto update_rate_and_reset; + } + + /* Update sampling information */ + bfqd->peak_rate_samples++; + + if ((bfqd->rq_in_driver > 0 || + now_ns - bfqd->last_completion < BFQ_MIN_TT) + && get_sdist(bfqd->last_position, rq) < BFQQ_SEEK_THR) + bfqd->sequential_samples++; + + bfqd->tot_sectors_dispatched += blk_rq_sectors(rq); + + /* Reset max observed rq size every 32 dispatches */ + if (likely(bfqd->peak_rate_samples % 32)) + bfqd->last_rq_max_size = + max_t(u32, blk_rq_sectors(rq), bfqd->last_rq_max_size); + else + bfqd->last_rq_max_size = blk_rq_sectors(rq); + + bfqd->delta_from_first = now_ns - bfqd->first_dispatch; + + bfq_log(bfqd, + "update_peak_rate: added samples %u/%u tot_sects %llu delta_first %lluus", + bfqd->peak_rate_samples, bfqd->sequential_samples, + bfqd->tot_sectors_dispatched, + bfqd->delta_from_first>>10); + + /* Target observation interval not yet reached, go on sampling */ + if (bfqd->delta_from_first < BFQ_RATE_REF_INTERVAL) + goto update_last_values; + +update_rate_and_reset: + bfq_update_rate_reset(bfqd, rq); +update_last_values: + bfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); + bfqd->last_dispatch = now_ns; + + bfq_log(bfqd, + "update_peak_rate: delta_first %lluus last_pos %llu peak_rate %llu", + (now_ns - bfqd->first_dispatch)>>10, + (unsigned long long) bfqd->last_position, + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + bfq_log(bfqd, + "update_peak_rate: samples at end %d", bfqd->peak_rate_samples); +} + +/* + * Remove request from internal lists. + */ +static void bfq_dispatch_remove(struct request_queue *q, struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + + /* + * For consistency, the next instruction should have been + * executed after removing the request from the queue and + * dispatching it. We execute instead this instruction before + * bfq_remove_request() (and hence introduce a temporary + * inconsistency), for efficiency. In fact, should this + * dispatch occur for a non in-service bfqq, this anticipated + * increment prevents two counters related to bfqq->dispatched + * from risking to be, first, uselessly decremented, and then + * incremented again when the (new) value of bfqq->dispatched + * happens to be taken into account. + */ + bfqq->dispatched++; + bfq_update_peak_rate(q->elevator->elevator_data, rq); + + bfq_remove_request(q, rq); +} + +static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + BUG_ON(bfqq != bfqd->in_service_queue); + + /* + * If this bfqq is shared between multiple processes, check + * to make sure that those processes are still issuing I/Os + * within the mean seek distance. If not, it may be time to + * break the queues apart again. + */ + if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) + bfq_mark_bfqq_split_coop(bfqq); + + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { + if (bfqq->dispatched == 0) + /* + * Overloading budget_timeout field to store + * the time at which the queue remains with no + * backlog and no outstanding request; used by + * the weight-raising mechanism. + */ + bfqq->budget_timeout = jiffies; + + bfq_del_bfqq_busy(bfqd, bfqq, true); + } else { + bfq_requeue_bfqq(bfqd, bfqq, true); + /* + * Resort priority tree of potential close cooperators. + */ + bfq_pos_tree_add_move(bfqd, bfqq); + } + + /* + * All in-service entities must have been properly deactivated + * or requeued before executing the next function, which + * resets all in-service entites as no more in service. + */ + __bfq_bfqd_reset_in_service(bfqd); +} + +/** + * __bfq_bfqq_recalc_budget - try to adapt the budget to the @bfqq behavior. + * @bfqd: device data. + * @bfqq: queue to update. + * @reason: reason for expiration. + * + * Handle the feedback on @bfqq budget at queue expiration. + * See the body for detailed comments. + */ +static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + enum bfqq_expiration reason) +{ + struct request *next_rq; + int budget, min_budget; + + BUG_ON(bfqq != bfqd->in_service_queue); + + min_budget = bfq_min_budget(bfqd); + + if (bfqq->wr_coeff == 1) + budget = bfqq->max_budget; + else /* + * Use a constant, low budget for weight-raised queues, + * to help achieve a low latency. Keep it slightly higher + * than the minimum possible budget, to cause a little + * bit fewer expirations. + */ + budget = 2 * min_budget; + + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %d, budg left %d", + bfqq->entity.budget, bfq_bfqq_budget_left(bfqq)); + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %d, min budg %d", + budget, bfq_min_budget(bfqd)); + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: sync %d, seeky %d", + bfq_bfqq_sync(bfqq), BFQQ_SEEKY(bfqd->in_service_queue)); + + if (bfq_bfqq_sync(bfqq) && bfqq->wr_coeff == 1) { + switch (reason) { + /* + * Caveat: in all the following cases we trade latency + * for throughput. + */ + case BFQ_BFQQ_TOO_IDLE: + /* + * This is the only case where we may reduce + * the budget: if there is no request of the + * process still waiting for completion, then + * we assume (tentatively) that the timer has + * expired because the batch of requests of + * the process could have been served with a + * smaller budget. Hence, betting that + * process will behave in the same way when it + * becomes backlogged again, we reduce its + * next budget. As long as we guess right, + * this budget cut reduces the latency + * experienced by the process. + * + * However, if there are still outstanding + * requests, then the process may have not yet + * issued its next request just because it is + * still waiting for the completion of some of + * the still outstanding ones. So in this + * subcase we do not reduce its budget, on the + * contrary we increase it to possibly boost + * the throughput, as discussed in the + * comments to the BUDGET_TIMEOUT case. + */ + if (bfqq->dispatched > 0) /* still outstanding reqs */ + budget = min(budget * 2, bfqd->bfq_max_budget); + else { + if (budget > 5 * min_budget) + budget -= 4 * min_budget; + else + budget = min_budget; + } + break; + case BFQ_BFQQ_BUDGET_TIMEOUT: + /* + * We double the budget here because it gives + * the chance to boost the throughput if this + * is not a seeky process (and has bumped into + * this timeout because of, e.g., ZBR). + */ + budget = min(budget * 2, bfqd->bfq_max_budget); + break; + case BFQ_BFQQ_BUDGET_EXHAUSTED: + /* + * The process still has backlog, and did not + * let either the budget timeout or the disk + * idling timeout expire. Hence it is not + * seeky, has a short thinktime and may be + * happy with a higher budget too. So + * definitely increase the budget of this good + * candidate to boost the disk throughput. + */ + budget = min(budget * 4, bfqd->bfq_max_budget); + break; + case BFQ_BFQQ_NO_MORE_REQUESTS: + /* + * For queues that expire for this reason, it + * is particularly important to keep the + * budget close to the actual service they + * need. Doing so reduces the timestamp + * misalignment problem described in the + * comments in the body of + * __bfq_activate_entity. In fact, suppose + * that a queue systematically expires for + * BFQ_BFQQ_NO_MORE_REQUESTS and presents a + * new request in time to enjoy timestamp + * back-shifting. The larger the budget of the + * queue is with respect to the service the + * queue actually requests in each service + * slot, the more times the queue can be + * reactivated with the same virtual finish + * time. It follows that, even if this finish + * time is pushed to the system virtual time + * to reduce the consequent timestamp + * misalignment, the queue unjustly enjoys for + * many re-activations a lower finish time + * than all newly activated queues. + * + * The service needed by bfqq is measured + * quite precisely by bfqq->entity.service. + * Since bfqq does not enjoy device idling, + * bfqq->entity.service is equal to the number + * of sectors that the process associated with + * bfqq requested to read/write before waiting + * for request completions, or blocking for + * other reasons. + */ + budget = max_t(int, bfqq->entity.service, min_budget); + break; + default: + return; + } + } else if (!bfq_bfqq_sync(bfqq)) + /* + * Async queues get always the maximum possible + * budget, as for them we do not care about latency + * (in addition, their ability to dispatch is limited + * by the charging factor). + */ + budget = bfqd->bfq_max_budget; + + bfqq->max_budget = budget; + + if (bfqd->budgets_assigned >= bfq_stats_min_budgets && + !bfqd->bfq_user_max_budget) + bfqq->max_budget = min(bfqq->max_budget, bfqd->bfq_max_budget); + + /* + * If there is still backlog, then assign a new budget, making + * sure that it is large enough for the next request. Since + * the finish time of bfqq must be kept in sync with the + * budget, be sure to call __bfq_bfqq_expire() *after* this + * update. + * + * If there is no backlog, then no need to update the budget; + * it will be updated on the arrival of a new request. + */ + next_rq = bfqq->next_rq; + if (next_rq) { + BUG_ON(reason == BFQ_BFQQ_TOO_IDLE || + reason == BFQ_BFQQ_NO_MORE_REQUESTS); + bfqq->entity.budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)); + BUG_ON(!bfq_bfqq_busy(bfqq)); + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + } + + bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %d", + next_rq ? blk_rq_sectors(next_rq) : 0, + bfqq->entity.budget); +} + +/* + * Return true if the process associated with bfqq is "slow". The slow + * flag is used, in addition to the budget timeout, to reduce the + * amount of service provided to seeky processes, and thus reduce + * their chances to lower the throughput. More details in the comments + * on the function bfq_bfqq_expire(). + * + * An important observation is in order: as discussed in the comments + * on the function bfq_update_peak_rate(), with devices with internal + * queues, it is hard if ever possible to know when and for how long + * an I/O request is processed by the device (apart from the trivial + * I/O pattern where a new request is dispatched only after the + * previous one has been completed). This makes it hard to evaluate + * the real rate at which the I/O requests of each bfq_queue are + * served. In fact, for an I/O scheduler like BFQ, serving a + * bfq_queue means just dispatching its requests during its service + * slot (i.e., until the budget of the queue is exhausted, or the + * queue remains idle, or, finally, a timeout fires). But, during the + * service slot of a bfq_queue, around 100 ms at most, the device may + * be even still processing requests of bfq_queues served in previous + * service slots. On the opposite end, the requests of the in-service + * bfq_queue may be completed after the service slot of the queue + * finishes. + * + * Anyway, unless more sophisticated solutions are used + * (where possible), the sum of the sizes of the requests dispatched + * during the service slot of a bfq_queue is probably the only + * approximation available for the service received by the bfq_queue + * during its service slot. And this sum is the quantity used in this + * function to evaluate the I/O speed of a process. + */ +static bool bfq_bfqq_is_slow(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool compensate, enum bfqq_expiration reason, + unsigned long *delta_ms) +{ + ktime_t delta_ktime; + u32 delta_usecs; + bool slow = BFQQ_SEEKY(bfqq); /* if delta too short, use seekyness */ + + if (!bfq_bfqq_sync(bfqq)) + return false; + + if (compensate) + delta_ktime = bfqd->last_idling_start; + else + delta_ktime = ktime_get(); + delta_ktime = ktime_sub(delta_ktime, bfqd->last_budget_start); + delta_usecs = ktime_to_us(delta_ktime); + + /* don't use too short time intervals */ + if (delta_usecs < 1000) { + if (blk_queue_nonrot(bfqd->queue)) + /* + * give same worst-case guarantees as idling + * for seeky + */ + *delta_ms = BFQ_MIN_TT / NSEC_PER_MSEC; + else /* charge at least one seek */ + *delta_ms = bfq_slice_idle / NSEC_PER_MSEC; + + bfq_log(bfqd, "bfq_bfqq_is_slow: too short %u", delta_usecs); + + return slow; + } + + *delta_ms = delta_usecs / USEC_PER_MSEC; + + /* + * Use only long (> 20ms) intervals to filter out excessive + * spikes in service rate estimation. + */ + if (delta_usecs > 20000) { + /* + * Caveat for rotational devices: processes doing I/O + * in the slower disk zones tend to be slow(er) even + * if not seeky. In this respect, the estimated peak + * rate is likely to be an average over the disk + * surface. Accordingly, to not be too harsh with + * unlucky processes, a process is deemed slow only if + * its rate has been lower than half of the estimated + * peak rate. + */ + slow = bfqq->entity.service < bfqd->bfq_max_budget / 2; + bfq_log(bfqd, "bfq_bfqq_is_slow: relative rate %d/%d", + bfqq->entity.service, bfqd->bfq_max_budget); + } + + bfq_log_bfqq(bfqd, bfqq, "bfq_bfqq_is_slow: slow %d", slow); + + return slow; +} + +/* + * To be deemed as soft real-time, an application must meet two + * requirements. First, the application must not require an average + * bandwidth higher than the approximate bandwidth required to playback or + * record a compressed high-definition video. + * The next function is invoked on the completion of the last request of a + * batch, to compute the next-start time instant, soft_rt_next_start, such + * that, if the next request of the application does not arrive before + * soft_rt_next_start, then the above requirement on the bandwidth is met. + * + * The second requirement is that the request pattern of the application is + * isochronous, i.e., that, after issuing a request or a batch of requests, + * the application stops issuing new requests until all its pending requests + * have been completed. After that, the application may issue a new batch, + * and so on. + * For this reason the next function is invoked to compute + * soft_rt_next_start only for applications that meet this requirement, + * whereas soft_rt_next_start is set to infinity for applications that do + * not. + * + * Unfortunately, even a greedy application may happen to behave in an + * isochronous way if the CPU load is high. In fact, the application may + * stop issuing requests while the CPUs are busy serving other processes, + * then restart, then stop again for a while, and so on. In addition, if + * the disk achieves a low enough throughput with the request pattern + * issued by the application (e.g., because the request pattern is random + * and/or the device is slow), then the application may meet the above + * bandwidth requirement too. To prevent such a greedy application to be + * deemed as soft real-time, a further rule is used in the computation of + * soft_rt_next_start: soft_rt_next_start must be higher than the current + * time plus the maximum time for which the arrival of a request is waited + * for when a sync queue becomes idle, namely bfqd->bfq_slice_idle. + * This filters out greedy applications, as the latter issue instead their + * next request as soon as possible after the last one has been completed + * (in contrast, when a batch of requests is completed, a soft real-time + * application spends some time processing data). + * + * Unfortunately, the last filter may easily generate false positives if + * only bfqd->bfq_slice_idle is used as a reference time interval and one + * or both the following cases occur: + * 1) HZ is so low that the duration of a jiffy is comparable to or higher + * than bfqd->bfq_slice_idle. This happens, e.g., on slow devices with + * HZ=100. + * 2) jiffies, instead of increasing at a constant rate, may stop increasing + * for a while, then suddenly 'jump' by several units to recover the lost + * increments. This seems to happen, e.g., inside virtual machines. + * To address this issue, we do not use as a reference time interval just + * bfqd->bfq_slice_idle, but bfqd->bfq_slice_idle plus a few jiffies. In + * particular we add the minimum number of jiffies for which the filter + * seems to be quite precise also in embedded systems and KVM/QEMU virtual + * machines. + */ +static unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqd, bfqq, +"softrt_next_start: service_blkg %lu soft_rate %u sects/sec interval %u", + bfqq->service_from_backlogged, + bfqd->bfq_wr_max_softrt_rate, + jiffies_to_msecs(HZ * bfqq->service_from_backlogged / + bfqd->bfq_wr_max_softrt_rate)); + + return max(bfqq->last_idle_bklogged + + HZ * bfqq->service_from_backlogged / + bfqd->bfq_wr_max_softrt_rate, + jiffies + nsecs_to_jiffies(bfqq->bfqd->bfq_slice_idle) + 4); +} + +/** + * bfq_bfqq_expire - expire a queue. + * @bfqd: device owning the queue. + * @bfqq: the queue to expire. + * @compensate: if true, compensate for the time spent idling. + * @reason: the reason causing the expiration. + * + * If the process associated with bfqq does slow I/O (e.g., because it + * issues random requests), we charge bfqq with the time it has been + * in service instead of the service it has received (see + * bfq_bfqq_charge_time for details on how this goal is achieved). As + * a consequence, bfqq will typically get higher timestamps upon + * reactivation, and hence it will be rescheduled as if it had + * received more service than what it has actually received. In the + * end, bfqq receives less service in proportion to how slowly its + * associated process consumes its budgets (and hence how seriously it + * tends to lower the throughput). In addition, this time-charging + * strategy guarantees time fairness among slow processes. In + * contrast, if the process associated with bfqq is not slow, we + * charge bfqq exactly with the service it has received. + * + * Charging time to the first type of queues and the exact service to + * the other has the effect of using the WF2Q+ policy to schedule the + * former on a timeslice basis, without violating service domain + * guarantees among the latter. + */ +static void bfq_bfqq_expire(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool compensate, + enum bfqq_expiration reason) +{ + bool slow; + unsigned long delta = 0; + struct bfq_entity *entity = &bfqq->entity; + int ref; + + BUG_ON(bfqq != bfqd->in_service_queue); + + /* + * Check whether the process is slow (see bfq_bfqq_is_slow). + */ + slow = bfq_bfqq_is_slow(bfqd, bfqq, compensate, reason, &delta); + + /* + * Increase service_from_backlogged before next statement, + * because the possible next invocation of + * bfq_bfqq_charge_time would likely inflate + * entity->service. In contrast, service_from_backlogged must + * contain real service, to enable the soft real-time + * heuristic to correctly compute the bandwidth consumed by + * bfqq. + */ + bfqq->service_from_backlogged += entity->service; + + /* + * As above explained, charge slow (typically seeky) and + * timed-out queues with the time and not the service + * received, to favor sequential workloads. + * + * Processes doing I/O in the slower disk zones will tend to + * be slow(er) even if not seeky. Therefore, since the + * estimated peak rate is actually an average over the disk + * surface, these processes may timeout just for bad luck. To + * avoid punishing them, do not charge time to processes that + * succeeded in consuming at least 2/3 of their budget. This + * allows BFQ to preserve enough elasticity to still perform + * bandwidth, and not time, distribution with little unlucky + * or quasi-sequential processes. + */ + if (bfqq->wr_coeff == 1 && + (slow || + (reason == BFQ_BFQQ_BUDGET_TIMEOUT && + bfq_bfqq_budget_left(bfqq) >= entity->budget / 3))) + bfq_bfqq_charge_time(bfqd, bfqq, delta); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + if (reason == BFQ_BFQQ_TOO_IDLE && + entity->service <= 2 * entity->budget / 10) + bfq_clear_bfqq_IO_bound(bfqq); + + if (bfqd->low_latency && bfqq->wr_coeff == 1) + bfqq->last_wr_start_finish = jiffies; + + if (bfqd->low_latency && bfqd->bfq_wr_max_softrt_rate > 0 && + RB_EMPTY_ROOT(&bfqq->sort_list)) { + /* + * If we get here, and there are no outstanding + * requests, then the request pattern is isochronous + * (see the comments on the function + * bfq_bfqq_softrt_next_start()). Thus we can compute + * soft_rt_next_start. If, instead, the queue still + * has outstanding requests, then we have to wait for + * the completion of all the outstanding requests to + * discover whether the request pattern is actually + * isochronous. + */ + BUG_ON(bfqd->busy_queues < 1); + if (bfqq->dispatched == 0) { + bfqq->soft_rt_next_start = + bfq_bfqq_softrt_next_start(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, "new soft_rt_next %lu", + bfqq->soft_rt_next_start); + } else { + /* + * The application is still waiting for the + * completion of one or more requests: + * prevent it from possibly being incorrectly + * deemed as soft real-time by setting its + * soft_rt_next_start to infinity. In fact, + * without this assignment, the application + * would be incorrectly deemed as soft + * real-time if: + * 1) it issued a new request before the + * completion of all its in-flight + * requests, and + * 2) at that time, its soft_rt_next_start + * happened to be in the past. + */ + bfqq->soft_rt_next_start = + bfq_greatest_from_now(); + /* + * Schedule an update of soft_rt_next_start to when + * the task may be discovered to be isochronous. + */ + bfq_mark_bfqq_softrt_update(bfqq); + } + } + + bfq_log_bfqq(bfqd, bfqq, + "expire (%d, slow %d, num_disp %d, short_ttime %d, weight %d)", + reason, slow, bfqq->dispatched, + bfq_bfqq_has_short_ttime(bfqq), entity->weight); + + /* + * Increase, decrease or leave budget unchanged according to + * reason. + */ + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + __bfq_bfqq_recalc_budget(bfqd, bfqq, reason); + BUG_ON(bfqq->next_rq == NULL && + bfqq->entity.budget < bfqq->entity.service); + ref = bfqq->ref; + __bfq_bfqq_expire(bfqd, bfqq); + + BUG_ON(ref > 1 && + !bfq_bfqq_busy(bfqq) && reason == BFQ_BFQQ_BUDGET_EXHAUSTED && + !bfq_class_idle(bfqq)); + + /* mark bfqq as waiting a request only if a bic still points to it */ + if (ref > 1 && !bfq_bfqq_busy(bfqq) && + reason != BFQ_BFQQ_BUDGET_TIMEOUT && + reason != BFQ_BFQQ_BUDGET_EXHAUSTED) + bfq_mark_bfqq_non_blocking_wait_rq(bfqq); +} + +/* + * Budget timeout is not implemented through a dedicated timer, but + * just checked on request arrivals and completions, as well as on + * idle timer expirations. + */ +static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) +{ + return time_is_before_eq_jiffies(bfqq->budget_timeout); +} + +/* + * If we expire a queue that is actively waiting (i.e., with the + * device idled) for the arrival of a new request, then we may incur + * the timestamp misalignment problem described in the body of the + * function __bfq_activate_entity. Hence we return true only if this + * condition does not hold, or if the queue is slow enough to deserve + * only to be kicked off for preserving a high throughput. + */ +static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqq->bfqd, bfqq, + "may_budget_timeout: wait_request %d left %d timeout %d", + bfq_bfqq_wait_request(bfqq), + bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3, + bfq_bfqq_budget_timeout(bfqq)); + + return (!bfq_bfqq_wait_request(bfqq) || + bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3) + && + bfq_bfqq_budget_timeout(bfqq); +} + +/* + * For a queue that becomes empty, device idling is allowed only if + * this function returns true for that queue. As a consequence, since + * device idling plays a critical role for both throughput boosting + * and service guarantees, the return value of this function plays a + * critical role as well. + * + * In a nutshell, this function returns true only if idling is + * beneficial for throughput or, even if detrimental for throughput, + * idling is however necessary to preserve service guarantees (low + * latency, desired throughput distribution, ...). In particular, on + * NCQ-capable devices, this function tries to return false, so as to + * help keep the drives' internal queues full, whenever this helps the + * device boost the throughput without causing any service-guarantee + * issue. + * + * In more detail, the return value of this function is obtained by, + * first, computing a number of boolean variables that take into + * account throughput and service-guarantee issues, and, then, + * combining these variables in a logical expression. Most of the + * issues taken into account are not trivial. We discuss these issues + * while introducing the variables. + */ +static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq) +{ + struct bfq_data *bfqd = bfqq->bfqd; + bool rot_without_queueing = + !blk_queue_nonrot(bfqd->queue) && !bfqd->hw_tag, + bfqq_sequential_and_IO_bound, + idling_boosts_thr, idling_boosts_thr_without_issues, + idling_needed_for_service_guarantees, + asymmetric_scenario; + + if (bfqd->strict_guarantees) + return true; + + /* + * Idling is performed only if slice_idle > 0. In addition, we + * do not idle if + * (a) bfqq is async + * (b) bfqq is in the idle io prio class: in this case we do + * not idle because we want to minimize the bandwidth that + * queues in this class can steal to higher-priority queues + */ + if (bfqd->bfq_slice_idle == 0 || !bfq_bfqq_sync(bfqq) || + bfq_class_idle(bfqq)) + return false; + + bfqq_sequential_and_IO_bound = !BFQQ_SEEKY(bfqq) && + bfq_bfqq_IO_bound(bfqq) && bfq_bfqq_has_short_ttime(bfqq); + /* + * The next variable takes into account the cases where idling + * boosts the throughput. + * + * The value of the variable is computed considering, first, that + * idling is virtually always beneficial for the throughput if: + * (a) the device is not NCQ-capable and rotational, or + * (b) regardless of the presence of NCQ, the device is rotational and + * the request pattern for bfqq is I/O-bound and sequential, or + * (c) regardless of whether it is rotational, the device is + * not NCQ-capable and the request pattern for bfqq is + * I/O-bound and sequential. + * + * Secondly, and in contrast to the above item (b), idling an + * NCQ-capable flash-based device would not boost the + * throughput even with sequential I/O; rather it would lower + * the throughput in proportion to how fast the device + * is. Accordingly, the next variable is true if any of the + * above conditions (a), (b) or (c) is true, and, in + * particular, happens to be false if bfqd is an NCQ-capable + * flash-based device. + */ + idling_boosts_thr = rot_without_queueing || + ((!blk_queue_nonrot(bfqd->queue) || !bfqd->hw_tag) && + bfqq_sequential_and_IO_bound); + + /* + * The value of the next variable, + * idling_boosts_thr_without_issues, is equal to that of + * idling_boosts_thr, unless a special case holds. In this + * special case, described below, idling may cause problems to + * weight-raised queues. + * + * When the request pool is saturated (e.g., in the presence + * of write hogs), if the processes associated with + * non-weight-raised queues ask for requests at a lower rate, + * then processes associated with weight-raised queues have a + * higher probability to get a request from the pool + * immediately (or at least soon) when they need one. Thus + * they have a higher probability to actually get a fraction + * of the device throughput proportional to their high + * weight. This is especially true with NCQ-capable drives, + * which enqueue several requests in advance, and further + * reorder internally-queued requests. + * + * For this reason, we force to false the value of + * idling_boosts_thr_without_issues if there are weight-raised + * busy queues. In this case, and if bfqq is not weight-raised, + * this guarantees that the device is not idled for bfqq (if, + * instead, bfqq is weight-raised, then idling will be + * guaranteed by another variable, see below). Combined with + * the timestamping rules of BFQ (see [1] for details), this + * behavior causes bfqq, and hence any sync non-weight-raised + * queue, to get a lower number of requests served, and thus + * to ask for a lower number of requests from the request + * pool, before the busy weight-raised queues get served + * again. This often mitigates starvation problems in the + * presence of heavy write workloads and NCQ, thereby + * guaranteeing a higher application and system responsiveness + * in these hostile scenarios. + */ + idling_boosts_thr_without_issues = idling_boosts_thr && + bfqd->wr_busy_queues == 0; + + /* + * There is then a case where idling must be performed not + * for throughput concerns, but to preserve service + * guarantees. + * + * To introduce this case, we can note that allowing the drive + * to enqueue more than one request at a time, and hence + * delegating de facto final scheduling decisions to the + * drive's internal scheduler, entails loss of control on the + * actual request service order. In particular, the critical + * situation is when requests from different processes happen + * to be present, at the same time, in the internal queue(s) + * of the drive. In such a situation, the drive, by deciding + * the service order of the internally-queued requests, does + * determine also the actual throughput distribution among + * these processes. But the drive typically has no notion or + * concern about per-process throughput distribution, and + * makes its decisions only on a per-request basis. Therefore, + * the service distribution enforced by the drive's internal + * scheduler is likely to coincide with the desired + * device-throughput distribution only in a completely + * symmetric scenario where: + * (i) each of these processes must get the same throughput as + * the others; + * (ii) all these processes have the same I/O pattern + * (either sequential or random). + * In fact, in such a scenario, the drive will tend to treat + * the requests of each of these processes in about the same + * way as the requests of the others, and thus to provide + * each of these processes with about the same throughput + * (which is exactly the desired throughput distribution). In + * contrast, in any asymmetric scenario, device idling is + * certainly needed to guarantee that bfqq receives its + * assigned fraction of the device throughput (see [1] for + * details). + * + * We address this issue by controlling, actually, only the + * symmetry sub-condition (i), i.e., provided that + * sub-condition (i) holds, idling is not performed, + * regardless of whether sub-condition (ii) holds. In other + * words, only if sub-condition (i) holds, then idling is + * allowed, and the device tends to be prevented from queueing + * many requests, possibly of several processes. The reason + * for not controlling also sub-condition (ii) is that we + * exploit preemption to preserve guarantees in case of + * symmetric scenarios, even if (ii) does not hold, as + * explained in the next two paragraphs. + * + * Even if a queue, say Q, is expired when it remains idle, Q + * can still preempt the new in-service queue if the next + * request of Q arrives soon (see the comments on + * bfq_bfqq_update_budg_for_activation). If all queues and + * groups have the same weight, this form of preemption, + * combined with the hole-recovery heuristic described in the + * comments on function bfq_bfqq_update_budg_for_activation, + * are enough to preserve a correct bandwidth distribution in + * the mid term, even without idling. In fact, even if not + * idling allows the internal queues of the device to contain + * many requests, and thus to reorder requests, we can rather + * safely assume that the internal scheduler still preserves a + * minimum of mid-term fairness. The motivation for using + * preemption instead of idling is that, by not idling, + * service guarantees are preserved without minimally + * sacrificing throughput. In other words, both a high + * throughput and its desired distribution are obtained. + * + * More precisely, this preemption-based, idleless approach + * provides fairness in terms of IOPS, and not sectors per + * second. This can be seen with a simple example. Suppose + * that there are two queues with the same weight, but that + * the first queue receives requests of 8 sectors, while the + * second queue receives requests of 1024 sectors. In + * addition, suppose that each of the two queues contains at + * most one request at a time, which implies that each queue + * always remains idle after it is served. Finally, after + * remaining idle, each queue receives very quickly a new + * request. It follows that the two queues are served + * alternatively, preempting each other if needed. This + * implies that, although both queues have the same weight, + * the queue with large requests receives a service that is + * 1024/8 times as high as the service received by the other + * queue. + * + * On the other hand, device idling is performed, and thus + * pure sector-domain guarantees are provided, for the + * following queues, which are likely to need stronger + * throughput guarantees: weight-raised queues, and queues + * with a higher weight than other queues. When such queues + * are active, sub-condition (i) is false, which triggers + * device idling. + * + * According to the above considerations, the next variable is + * true (only) if sub-condition (i) holds. To compute the + * value of this variable, we not only use the return value of + * the function bfq_symmetric_scenario(), but also check + * whether bfqq is being weight-raised, because + * bfq_symmetric_scenario() does not take into account also + * weight-raised queues (see comments on + * bfq_weights_tree_add()). + * + * As a side note, it is worth considering that the above + * device-idling countermeasures may however fail in the + * following unlucky scenario: if idling is (correctly) + * disabled in a time period during which all symmetry + * sub-conditions hold, and hence the device is allowed to + * enqueue many requests, but at some later point in time some + * sub-condition stops to hold, then it may become impossible + * to let requests be served in the desired order until all + * the requests already queued in the device have been served. + */ + asymmetric_scenario = bfqq->wr_coeff > 1 || + !bfq_symmetric_scenario(bfqd); + + /* + * Finally, there is a case where maximizing throughput is the + * best choice even if it may cause unfairness toward + * bfqq. Such a case is when bfqq became active in a burst of + * queue activations. Queues that became active during a large + * burst benefit only from throughput, as discussed in the + * comments on bfq_handle_burst. Thus, if bfqq became active + * in a burst and not idling the device maximizes throughput, + * then the device must no be idled, because not idling the + * device provides bfqq and all other queues in the burst with + * maximum benefit. Combining this and the above case, we can + * now establish when idling is actually needed to preserve + * service guarantees. + */ + idling_needed_for_service_guarantees = + asymmetric_scenario && !bfq_bfqq_in_large_burst(bfqq); + + /* + * We have now all the components we need to compute the + * return value of the function, which is true only if idling + * either boosts the throughput (without issues), or is + * necessary to preserve service guarantees. + */ + bfq_log_bfqq(bfqd, bfqq, "may_idle: sync %d idling_boosts_thr %d", + bfq_bfqq_sync(bfqq), idling_boosts_thr); + + bfq_log_bfqq(bfqd, bfqq, + "may_idle: wr_busy %d boosts %d IO-bound %d guar %d", + bfqd->wr_busy_queues, + idling_boosts_thr_without_issues, + bfq_bfqq_IO_bound(bfqq), + idling_needed_for_service_guarantees); + + return idling_boosts_thr_without_issues || + idling_needed_for_service_guarantees; +} + +/* + * If the in-service queue is empty but the function bfq_bfqq_may_idle + * returns true, then: + * 1) the queue must remain in service and cannot be expired, and + * 2) the device must be idled to wait for the possible arrival of a new + * request for the queue. + * See the comments on the function bfq_bfqq_may_idle for the reasons + * why performing device idling is the best choice to boost the throughput + * and preserve service guarantees when bfq_bfqq_may_idle itself + * returns true. + */ +static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq) +{ + return RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_may_idle(bfqq); +} + +/* + * Select a queue for service. If we have a current queue in service, + * check whether to continue servicing it, or retrieve and set a new one. + */ +static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq; + struct request *next_rq; + enum bfqq_expiration reason = BFQ_BFQQ_BUDGET_TIMEOUT; + + bfqq = bfqd->in_service_queue; + if (!bfqq) + goto new_queue; + + bfq_log_bfqq(bfqd, bfqq, "select_queue: already in-service queue"); + + if (bfq_may_expire_for_budg_timeout(bfqq) && + !bfq_bfqq_wait_request(bfqq) && + !bfq_bfqq_must_idle(bfqq)) + goto expire; + +check_queue: + /* + * This loop is rarely executed more than once. Even when it + * happens, it is much more convenient to re-execute this loop + * than to return NULL and trigger a new dispatch to get a + * request served. + */ + next_rq = bfqq->next_rq; + /* + * If bfqq has requests queued and it has enough budget left to + * serve them, keep the queue, otherwise expire it. + */ + if (next_rq) { + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + + if (bfq_serv_to_charge(next_rq, bfqq) > + bfq_bfqq_budget_left(bfqq)) { + /* + * Expire the queue for budget exhaustion, + * which makes sure that the next budget is + * enough to serve the next request, even if + * it comes from the fifo expired path. + */ + reason = BFQ_BFQQ_BUDGET_EXHAUSTED; + goto expire; + } else { + /* + * The idle timer may be pending because we may + * not disable disk idling even when a new request + * arrives. + */ + if (bfq_bfqq_wait_request(bfqq)) { + /* + * If we get here: 1) at least a new request + * has arrived but we have not disabled the + * timer because the request was too small, + * 2) then the block layer has unplugged + * the device, causing the dispatch to be + * invoked. + * + * Since the device is unplugged, now the + * requests are probably large enough to + * provide a reasonable throughput. + * So we disable idling. + */ + bfq_clear_bfqq_wait_request(bfqq); + hrtimer_try_to_cancel(&bfqd->idle_slice_timer); + bfqg_stats_update_idle_time(bfqq_group(bfqq)); + } + goto keep_queue; + } + } + + /* + * No requests pending. However, if the in-service queue is idling + * for a new request, or has requests waiting for a completion and + * may idle after their completion, then keep it anyway. + */ + if (bfq_bfqq_wait_request(bfqq) || + (bfqq->dispatched != 0 && bfq_bfqq_may_idle(bfqq))) { + bfqq = NULL; + goto keep_queue; + } + + reason = BFQ_BFQQ_NO_MORE_REQUESTS; +expire: + bfq_bfqq_expire(bfqd, bfqq, false, reason); +new_queue: + bfqq = bfq_set_in_service_queue(bfqd); + if (bfqq) { + bfq_log_bfqq(bfqd, bfqq, "select_queue: checking new queue"); + goto check_queue; + } +keep_queue: + if (bfqq) + bfq_log_bfqq(bfqd, bfqq, "select_queue: returned this queue"); + else + bfq_log(bfqd, "select_queue: no queue returned"); + + return bfqq; +} + +static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + + if (bfqq->wr_coeff > 1) { /* queue is being weight-raised */ + BUG_ON(bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + time_is_after_jiffies(bfqq->last_wr_start_finish)); + + bfq_log_bfqq(bfqd, bfqq, + "raising period dur %u/%u msec, old coeff %u, w %d(%d)", + jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqq->wr_coeff, + bfqq->entity.weight, bfqq->entity.orig_weight); + + BUG_ON(bfqq != bfqd->in_service_queue && entity->weight != + entity->orig_weight * bfqq->wr_coeff); + if (entity->prio_changed) + bfq_log_bfqq(bfqd, bfqq, "WARN: pending prio change"); + + /* + * If the queue was activated in a burst, or too much + * time has elapsed from the beginning of this + * weight-raising period, then end weight raising. + */ + if (bfq_bfqq_in_large_burst(bfqq)) + bfq_bfqq_end_wr(bfqq); + else if (time_is_before_jiffies(bfqq->last_wr_start_finish + + bfqq->wr_cur_max_time)) { + if (bfqq->wr_cur_max_time != bfqd->bfq_wr_rt_max_time || + time_is_before_jiffies(bfqq->wr_start_at_switch_to_srt + + bfq_wr_duration(bfqd))) + bfq_bfqq_end_wr(bfqq); + else { + /* switch back to interactive wr */ + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + bfqq->last_wr_start_finish = + bfqq->wr_start_at_switch_to_srt; + BUG_ON(time_is_after_jiffies( + bfqq->last_wr_start_finish)); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, bfqq, + "back to interactive wr"); + } + } + } + /* + * To improve latency (for this or other queues), immediately + * update weight both if it must be raised and if it must be + * lowered. Since, entity may be on some active tree here, and + * might have a pending change of its ioprio class, invoke + * next function with the last parameter unset (see the + * comments on the function). + */ + if ((entity->weight > entity->orig_weight) != (bfqq->wr_coeff > 1)) + __bfq_entity_update_weight_prio(bfq_entity_service_tree(entity), + entity, false); +} + +/* + * Dispatch next request from bfqq. + */ +static struct request *bfq_dispatch_rq_from_bfqq(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + struct request *rq = bfqq->next_rq; + unsigned long service_to_charge; + + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + BUG_ON(!rq); + service_to_charge = bfq_serv_to_charge(rq, bfqq); + + BUG_ON(service_to_charge > bfq_bfqq_budget_left(bfqq)); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + bfq_bfqq_served(bfqq, service_to_charge); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + bfq_dispatch_remove(bfqd->queue, rq); + + /* + * If weight raising has to terminate for bfqq, then next + * function causes an immediate update of bfqq's weight, + * without waiting for next activation. As a consequence, on + * expiration, bfqq will be timestamped as if has never been + * weight-raised during this service slot, even if it has + * received part or even most of the service as a + * weight-raised queue. This inflates bfqq's timestamps, which + * is beneficial, as bfqq is then more willing to leave the + * device immediately to possible other weight-raised queues. + */ + bfq_update_wr_data(bfqd, bfqq); + + bfq_log_bfqq(bfqd, bfqq, + "dispatched %u sec req (%llu), budg left %d, new disp_nr %d", + blk_rq_sectors(rq), + (unsigned long long) blk_rq_pos(rq), + bfq_bfqq_budget_left(bfqq), + bfqq->dispatched); + + /* + * Expire bfqq, pretending that its budget expired, if bfqq + * belongs to CLASS_IDLE and other queues are waiting for + * service. + */ + if (bfqd->busy_queues > 1 && bfq_class_idle(bfqq)) + goto expire; + + return rq; + +expire: + bfq_bfqq_expire(bfqd, bfqq, false, BFQ_BFQQ_BUDGET_EXHAUSTED); + return rq; +} + +static bool bfq_has_work(struct blk_mq_hw_ctx *hctx) +{ + struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; + + bfq_log(bfqd, "has_work, dispatch_non_empty %d busy_queues %d", + !list_empty_careful(&bfqd->dispatch), bfqd->busy_queues > 0); + + /* + * Avoiding lock: a race on bfqd->busy_queues should cause at + * most a call to dispatch for nothing + */ + return !list_empty_careful(&bfqd->dispatch) || + bfqd->busy_queues > 0; +} + +static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) +{ + struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; + struct request *rq = NULL; + struct bfq_queue *bfqq = NULL; + + if (!list_empty(&bfqd->dispatch)) { + rq = list_first_entry(&bfqd->dispatch, struct request, + queuelist); + list_del_init(&rq->queuelist); + rq->rq_flags &= ~RQF_DISP_LIST; + + bfq_log(bfqd, + "dispatch requests: picked %p from dispatch list", rq); + bfqq = RQ_BFQQ(rq); + + if (bfqq) { + /* + * Increment counters here, because this + * dispatch does not follow the standard + * dispatch flow (where counters are + * incremented) + */ + bfqq->dispatched++; + + /* + * TESTING: reset DISP_LIST flag, because: 1) + * this rq this request has passed through + * get_rq_private, 2) then it will have + * put_rq_private invoked on it, and 3) in + * put_rq_private we use this flag to check + * that put_rq_private is not invoked on + * requests for which get_rq_private has been + * invoked. + */ + rq->rq_flags &= ~RQF_DISP_LIST; + goto inc_in_driver_start_rq; + } + + /* + * We exploit the put_rq_private hook to decrement + * rq_in_driver, but put_rq_private will not be + * invoked on this request. So, to avoid unbalance, + * just start this request, without incrementing + * rq_in_driver. As a negative consequence, + * rq_in_driver is deceptively lower than it should be + * while this request is in service. This may cause + * bfq_schedule_dispatch to be invoked uselessly. + * + * As for implementing an exact solution, the + * put_request hook, if defined, is probably invoked + * also on this request. So, by exploiting this hook, + * we could 1) increment rq_in_driver here, and 2) + * decrement it in put_request. Such a solution would + * let the value of the counter be always accurate, + * but it would entail using an extra interface + * function. This cost seems higher than the benefit, + * being the frequency of non-elevator-private + * requests very low. + */ + goto start_rq; + } + + bfq_log(bfqd, "dispatch requests: %d busy queues", bfqd->busy_queues); + + if (bfqd->busy_queues == 0) + goto exit; + + /* + * Force device to serve one request at a time if + * strict_guarantees is true. Forcing this service scheme is + * currently the ONLY way to guarantee that the request + * service order enforced by the scheduler is respected by a + * queueing device. Otherwise the device is free even to make + * some unlucky request wait for as long as the device + * wishes. + * + * Of course, serving one request at at time may cause loss of + * throughput. + */ + if (bfqd->strict_guarantees && bfqd->rq_in_driver > 0) + goto exit; + + bfqq = bfq_select_queue(bfqd); + if (!bfqq) + goto exit; + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + BUG_ON(bfq_bfqq_wait_request(bfqq)); + + rq = bfq_dispatch_rq_from_bfqq(bfqd, bfqq); + + BUG_ON(bfqq->next_rq == NULL && + bfqq->entity.budget < bfqq->entity.service); + + if (rq) { + inc_in_driver_start_rq: + bfqd->rq_in_driver++; + start_rq: + rq->rq_flags |= RQF_STARTED; + if (bfqq) + bfq_log_bfqq(bfqd, bfqq, + "dispatched %s request %p, rq_in_driver %d", + bfq_bfqq_sync(bfqq) ? "sync" : "async", + rq, + bfqd->rq_in_driver); + else + bfq_log(bfqd, + "dispatched request %p from dispatch list, rq_in_driver %d", + rq, bfqd->rq_in_driver); + } else + bfq_log(bfqd, + "returned NULL request, rq_in_driver %d", + bfqd->rq_in_driver); + +exit: + return rq; +} + +static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) +{ + struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; + struct request *rq; + + spin_lock_irq(&bfqd->lock); + + rq = __bfq_dispatch_request(hctx); + spin_unlock_irq(&bfqd->lock); + + return rq; +} + +/* + * Task holds one reference to the queue, dropped when task exits. Each rq + * in-flight on this queue also holds a reference, dropped when rq is freed. + * + * Scheduler lock must be held here. Recall not to use bfqq after calling + * this function on it. + */ +static void bfq_put_queue(struct bfq_queue *bfqq) +{ +#ifdef BFQ_GROUP_IOSCHED_ENABLED + struct bfq_group *bfqg = bfqq_group(bfqq); +#endif + + assert_spin_locked(&bfqq->bfqd->lock); + + BUG_ON(bfqq->ref <= 0); + + if (bfqq->bfqd) + bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p %d", bfqq, bfqq->ref); + + bfqq->ref--; + if (bfqq->ref) + return; + + BUG_ON(rb_first(&bfqq->sort_list)); + BUG_ON(bfqq->allocated != 0); + BUG_ON(bfqq->entity.tree); + BUG_ON(bfq_bfqq_busy(bfqq)); + + if (bfq_bfqq_sync(bfqq)) + /* + * The fact that this queue is being destroyed does not + * invalidate the fact that this queue may have been + * activated during the current burst. As a consequence, + * although the queue does not exist anymore, and hence + * needs to be removed from the burst list if there, + * the burst size has not to be decremented. + */ + hlist_del_init(&bfqq->burst_list_node); + + if (bfqq->bfqd) + bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p freed", bfqq); + + kmem_cache_free(bfq_pool, bfqq); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + bfqg_and_blkg_put(bfqg); +#endif +} + +static void bfq_put_cooperator(struct bfq_queue *bfqq) +{ + struct bfq_queue *__bfqq, *next; + + /* + * If this queue was scheduled to merge with another queue, be + * sure to drop the reference taken on that queue (and others in + * the merge chain). See bfq_setup_merge and bfq_merge_bfqqs. + */ + __bfqq = bfqq->new_bfqq; + while (__bfqq) { + if (__bfqq == bfqq) + break; + next = __bfqq->new_bfqq; + bfq_put_queue(__bfqq); + __bfqq = next; + } +} + +static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + if (bfqq == bfqd->in_service_queue) { + __bfq_bfqq_expire(bfqd, bfqq); + bfq_schedule_dispatch(bfqd); + } + + bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, bfqq->ref); + + bfq_put_cooperator(bfqq); + + bfq_put_queue(bfqq); /* release process reference */ +} + +static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync) +{ + struct bfq_queue *bfqq = bic_to_bfqq(bic, is_sync); + struct bfq_data *bfqd; + + if (bfqq) + bfqd = bfqq->bfqd; /* NULL if scheduler already exited */ + + if (bfqq && bfqd) { + unsigned long flags; + + spin_lock_irqsave(&bfqd->lock, flags); + + bfq_exit_bfqq(bfqd, bfqq); + bic_set_bfqq(bic, NULL, is_sync); + spin_unlock_irqrestore(&bfqd->lock, flags); + } +} + +static void bfq_exit_icq(struct io_cq *icq) +{ + struct bfq_io_cq *bic = icq_to_bic(icq); + + BUG_ON(!bic); + bfq_exit_icq_bfqq(bic, true); + bfq_exit_icq_bfqq(bic, false); +} + +/* + * Update the entity prio values; note that the new values will not + * be used until the next (re)activation. + */ +static void bfq_set_next_ioprio_data(struct bfq_queue *bfqq, + struct bfq_io_cq *bic) +{ + struct task_struct *tsk = current; + int ioprio_class; + struct bfq_data *bfqd = bfqq->bfqd; + + WARN_ON(!bfqd); + if (!bfqd) + return; + + ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); + switch (ioprio_class) { + default: + dev_err(bfqq->bfqd->queue->backing_dev_info->dev, + "bfq: bad prio class %d\n", ioprio_class); + case IOPRIO_CLASS_NONE: + /* + * No prio set, inherit CPU scheduling settings. + */ + bfqq->new_ioprio = task_nice_ioprio(tsk); + bfqq->new_ioprio_class = task_nice_ioclass(tsk); + break; + case IOPRIO_CLASS_RT: + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_RT; + break; + case IOPRIO_CLASS_BE: + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_BE; + break; + case IOPRIO_CLASS_IDLE: + bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE; + bfqq->new_ioprio = 7; + break; + } + + if (bfqq->new_ioprio >= IOPRIO_BE_NR) { + pr_crit("bfq_set_next_ioprio_data: new_ioprio %d\n", + bfqq->new_ioprio); + BUG(); + } + + bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "set_next_ioprio_data: bic_class %d prio %d class %d", + ioprio_class, bfqq->new_ioprio, bfqq->new_ioprio_class); +} + +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) +{ + struct bfq_data *bfqd = bic_to_bfqd(bic); + struct bfq_queue *bfqq; + unsigned long uninitialized_var(flags); + int ioprio = bic->icq.ioc->ioprio; + + /* + * This condition may trigger on a newly created bic, be sure to + * drop the lock before returning. + */ + if (unlikely(!bfqd) || likely(bic->ioprio == ioprio)) + return; + + bic->ioprio = ioprio; + + bfqq = bic_to_bfqq(bic, false); + if (bfqq) { + /* release process reference on this queue */ + bfq_put_queue(bfqq); + bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic); + bic_set_bfqq(bic, bfqq, false); + bfq_log_bfqq(bfqd, bfqq, + "check_ioprio_change: bfqq %p %d", + bfqq, bfqq->ref); + } + + bfqq = bic_to_bfqq(bic, true); + if (bfqq) + bfq_set_next_ioprio_data(bfqq, bic); +} + +static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct bfq_io_cq *bic, pid_t pid, int is_sync) +{ + RB_CLEAR_NODE(&bfqq->entity.rb_node); + INIT_LIST_HEAD(&bfqq->fifo); + INIT_HLIST_NODE(&bfqq->burst_list_node); + BUG_ON(!hlist_unhashed(&bfqq->burst_list_node)); + + bfqq->ref = 0; + bfqq->bfqd = bfqd; + + if (bic) + bfq_set_next_ioprio_data(bfqq, bic); + + if (is_sync) { + /* + * No need to mark as has_short_ttime if in + * idle_class, because no device idling is performed + * for queues in idle class + */ + if (!bfq_class_idle(bfqq)) + /* tentatively mark as has_short_ttime */ + bfq_mark_bfqq_has_short_ttime(bfqq); + bfq_mark_bfqq_sync(bfqq); + bfq_mark_bfqq_just_created(bfqq); + } else + bfq_clear_bfqq_sync(bfqq); + + bfqq->ttime.last_end_request = ktime_get_ns() - (1ULL<<32); + + bfq_mark_bfqq_IO_bound(bfqq); + + /* Tentative initial value to trade off between thr and lat */ + bfqq->max_budget = (2 * bfq_max_budget(bfqd)) / 3; + bfqq->pid = pid; + + bfqq->wr_coeff = 1; + bfqq->last_wr_start_finish = jiffies; + bfqq->wr_start_at_switch_to_srt = bfq_smallest_from_now(); + bfqq->budget_timeout = bfq_smallest_from_now(); + bfqq->split_time = bfq_smallest_from_now(); + + /* + * Set to the value for which bfqq will not be deemed as + * soft rt when it becomes backlogged. + */ + bfqq->soft_rt_next_start = bfq_greatest_from_now(); + + /* first request is almost certainly seeky */ + bfqq->seek_history = 1; +} + +static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd, + struct bfq_group *bfqg, + int ioprio_class, int ioprio) +{ + switch (ioprio_class) { + case IOPRIO_CLASS_RT: + return &bfqg->async_bfqq[0][ioprio]; + case IOPRIO_CLASS_NONE: + ioprio = IOPRIO_NORM; + /* fall through */ + case IOPRIO_CLASS_BE: + return &bfqg->async_bfqq[1][ioprio]; + case IOPRIO_CLASS_IDLE: + return &bfqg->async_idle_bfqq; + default: + BUG(); + } +} + +static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, + struct bio *bio, bool is_sync, + struct bfq_io_cq *bic) +{ + const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); + struct bfq_queue **async_bfqq = NULL; + struct bfq_queue *bfqq; + struct bfq_group *bfqg; + + rcu_read_lock(); + + bfqg = bfq_find_set_group(bfqd, bio_blkcg(bio)); + if (!bfqg) { + bfqq = &bfqd->oom_bfqq; + goto out; + } + + if (!is_sync) { + async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class, + ioprio); + bfqq = *async_bfqq; + if (bfqq) + goto out; + } + + bfqq = kmem_cache_alloc_node(bfq_pool, + GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN, + bfqd->queue->node); + + if (bfqq) { + bfq_init_bfqq(bfqd, bfqq, bic, current->pid, + is_sync); + bfq_init_entity(&bfqq->entity, bfqg); + bfq_log_bfqq(bfqd, bfqq, "allocated"); + } else { + bfqq = &bfqd->oom_bfqq; + bfq_log_bfqq(bfqd, bfqq, "using oom bfqq"); + goto out; + } + + /* + * Pin the queue now that it's allocated, scheduler exit will + * prune it. + */ + if (async_bfqq) { + bfqq->ref++; /* + * Extra group reference, w.r.t. sync + * queue. This extra reference is removed + * only if bfqq->bfqg disappears, to + * guarantee that this queue is not freed + * until its group goes away. + */ + bfq_log_bfqq(bfqd, bfqq, "get_queue, bfqq not in async: %p, %d", + bfqq, bfqq->ref); + *async_bfqq = bfqq; + } + +out: + bfqq->ref++; /* get a process reference to this queue */ + bfq_log_bfqq(bfqd, bfqq, "get_queue, at end: %p, %d", bfqq, bfqq->ref); + rcu_read_unlock(); + return bfqq; +} + +static void bfq_update_io_thinktime(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + struct bfq_ttime *ttime = &bfqq->ttime; + u64 elapsed = ktime_get_ns() - bfqq->ttime.last_end_request; + + elapsed = min_t(u64, elapsed, 2 * bfqd->bfq_slice_idle); + + ttime->ttime_samples = (7*bfqq->ttime.ttime_samples + 256) / 8; + ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8); + ttime->ttime_mean = div64_ul(ttime->ttime_total + 128, + ttime->ttime_samples); +} + +static void +bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct request *rq) +{ + bfqq->seek_history <<= 1; + bfqq->seek_history |= + get_sdist(bfqq->last_request_pos, rq) > BFQQ_SEEK_THR && + (!blk_queue_nonrot(bfqd->queue) || + blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT); +} + +static void bfq_update_has_short_ttime(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + struct bfq_io_cq *bic) +{ + bool has_short_ttime = true; + + /* + * No need to update has_short_ttime if bfqq is async or in + * idle io prio class, or if bfq_slice_idle is zero, because + * no device idling is performed for bfqq in this case. + */ + if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq) || + bfqd->bfq_slice_idle == 0) + return; + + /* Idle window just restored, statistics are meaningless. */ + if (time_is_after_eq_jiffies(bfqq->split_time + + bfqd->bfq_wr_min_idle_time)) + return; + + /* Think time is infinite if no process is linked to + * bfqq. Otherwise check average think time to + * decide whether to mark as has_short_ttime + */ + if (atomic_read(&bic->icq.ioc->active_ref) == 0 || + (bfq_sample_valid(bfqq->ttime.ttime_samples) && + bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle)) + has_short_ttime = false; + + bfq_log_bfqq(bfqd, bfqq, "update_has_short_ttime: has_short_ttime %d", + has_short_ttime); + + if (has_short_ttime) + bfq_mark_bfqq_has_short_ttime(bfqq); + else + bfq_clear_bfqq_has_short_ttime(bfqq); +} + +/* + * Called when a new fs request (rq) is added to bfqq. Check if there's + * something we should do about it. + */ +static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct request *rq) +{ + struct bfq_io_cq *bic = RQ_BIC(rq); + + if (rq->cmd_flags & REQ_META) + bfqq->meta_pending++; + + bfq_update_io_thinktime(bfqd, bfqq); + bfq_update_has_short_ttime(bfqd, bfqq, bic); + bfq_update_io_seektime(bfqd, bfqq, rq); + + bfq_log_bfqq(bfqd, bfqq, + "rq_enqueued: has_short_ttime=%d (seeky %d)", + bfq_bfqq_has_short_ttime(bfqq), BFQQ_SEEKY(bfqq)); + + bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); + + if (bfqq == bfqd->in_service_queue && bfq_bfqq_wait_request(bfqq)) { + bool small_req = bfqq->queued[rq_is_sync(rq)] == 1 && + blk_rq_sectors(rq) < 32; + bool budget_timeout = bfq_bfqq_budget_timeout(bfqq); + + /* + * There is just this request queued: if the request + * is small and the queue is not to be expired, then + * just exit. + * + * In this way, if the device is being idled to wait + * for a new request from the in-service queue, we + * avoid unplugging the device and committing the + * device to serve just a small request. On the + * contrary, we wait for the block layer to decide + * when to unplug the device: hopefully, new requests + * will be merged to this one quickly, then the device + * will be unplugged and larger requests will be + * dispatched. + */ + if (small_req && !budget_timeout) + return; + + /* + * A large enough request arrived, or the queue is to + * be expired: in both cases disk idling is to be + * stopped, so clear wait_request flag and reset + * timer. + */ + bfq_clear_bfqq_wait_request(bfqq); + hrtimer_try_to_cancel(&bfqd->idle_slice_timer); + bfqg_stats_update_idle_time(bfqq_group(bfqq)); + + /* + * The queue is not empty, because a new request just + * arrived. Hence we can safely expire the queue, in + * case of budget timeout, without risking that the + * timestamps of the queue are not updated correctly. + * See [1] for more details. + */ + if (budget_timeout) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); + } +} + +static void __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq), *new_bfqq; + BUG_ON(!bfqq); + + assert_spin_locked(&bfqd->lock); + + bfq_log_bfqq(bfqd, bfqq, "__insert_req: rq %p bfqq %p", rq, bfqq); + + /* + * An unplug may trigger a requeue of a request from the device + * driver: make sure we are in process context while trying to + * merge two bfq_queues. + */ + if (!in_interrupt()) { + new_bfqq = bfq_setup_cooperator(bfqd, bfqq, rq, true); + if (new_bfqq) { + if (bic_to_bfqq(RQ_BIC(rq), 1) != bfqq) + new_bfqq = bic_to_bfqq(RQ_BIC(rq), 1); + /* + * Release the request's reference to the old bfqq + * and make sure one is taken to the shared queue. + */ + new_bfqq->allocated++; + bfqq->allocated--; + bfq_log_bfqq(bfqd, bfqq, + "insert_request: new allocated %d", bfqq->allocated); + bfq_log_bfqq(bfqd, new_bfqq, + "insert_request: new_bfqq new allocated %d", + bfqq->allocated); + + new_bfqq->ref++; + bfq_clear_bfqq_just_created(bfqq); + /* + * If the bic associated with the process + * issuing this request still points to bfqq + * (and thus has not been already redirected + * to new_bfqq or even some other bfq_queue), + * then complete the merge and redirect it to + * new_bfqq. + */ + if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) + bfq_merge_bfqqs(bfqd, RQ_BIC(rq), + bfqq, new_bfqq); + /* + * rq is about to be enqueued into new_bfqq, + * release rq reference on bfqq + */ + bfq_put_queue(bfqq); + rq->elv.priv[1] = new_bfqq; + bfqq = new_bfqq; + } + } + + bfq_add_request(rq); + + rq->fifo_time = ktime_get_ns() + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; + list_add_tail(&rq->queuelist, &bfqq->fifo); + + bfq_rq_enqueued(bfqd, bfqq, rq); +} + +static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, + bool at_head) +{ + struct request_queue *q = hctx->queue; + struct bfq_data *bfqd = q->elevator->elevator_data; + + spin_lock_irq(&bfqd->lock); + if (blk_mq_sched_try_insert_merge(q, rq)) { + spin_unlock_irq(&bfqd->lock); + return; + } + + spin_unlock_irq(&bfqd->lock); + + blk_mq_sched_request_inserted(rq); + + spin_lock_irq(&bfqd->lock); + if (at_head || blk_rq_is_passthrough(rq)) { + struct bfq_queue *bfqq = RQ_BFQQ(rq); + + if (at_head) + list_add(&rq->queuelist, &bfqd->dispatch); + else + list_add_tail(&rq->queuelist, &bfqd->dispatch); + + rq->rq_flags |= RQF_DISP_LIST; + if (bfqq) + bfq_log_bfqq(bfqd, bfqq, + "insert_request %p in disp: at_head %d", + rq, at_head); + else + bfq_log(bfqd, + "insert_request %p in disp: at_head %d", + rq, at_head); + } else { + BUG_ON(!(rq->rq_flags & RQF_GOT)); + rq->rq_flags &= ~RQF_GOT; + + __bfq_insert_request(bfqd, rq); + + if (rq_mergeable(rq)) { + elv_rqhash_add(q, rq); + if (!q->last_merge) + q->last_merge = rq; + } + } + + spin_unlock_irq(&bfqd->lock); +} + +static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx, + struct list_head *list, bool at_head) +{ + while (!list_empty(list)) { + struct request *rq; + + rq = list_first_entry(list, struct request, queuelist); + list_del_init(&rq->queuelist); + bfq_insert_request(hctx, rq, at_head); + } +} + +static void bfq_update_hw_tag(struct bfq_data *bfqd) +{ + bfqd->max_rq_in_driver = max_t(int, bfqd->max_rq_in_driver, + bfqd->rq_in_driver); + + if (bfqd->hw_tag == 1) + return; + + /* + * This sample is valid if the number of outstanding requests + * is large enough to allow a queueing behavior. Note that the + * sum is not exact, as it's not taking into account deactivated + * requests. + */ + if (bfqd->rq_in_driver + bfqd->queued < BFQ_HW_QUEUE_THRESHOLD) + return; + + if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES) + return; + + bfqd->hw_tag = bfqd->max_rq_in_driver > BFQ_HW_QUEUE_THRESHOLD; + bfqd->max_rq_in_driver = 0; + bfqd->hw_tag_samples = 0; +} + +static void bfq_completed_request(struct bfq_queue *bfqq, struct bfq_data *bfqd) +{ + u64 now_ns; + u32 delta_us; + + bfq_update_hw_tag(bfqd); + + BUG_ON(!bfqd->rq_in_driver); + BUG_ON(!bfqq->dispatched); + bfqd->rq_in_driver--; + bfqq->dispatched--; + + bfq_log_bfqq(bfqd, bfqq, + "completed_requests: new disp %d, new rq_in_driver %d", + bfqq->dispatched, bfqd->rq_in_driver); + + if (!bfqq->dispatched && !bfq_bfqq_busy(bfqq)) { + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); + /* + * Set budget_timeout (which we overload to store the + * time at which the queue remains with no backlog and + * no outstanding request; used by the weight-raising + * mechanism). + */ + bfqq->budget_timeout = jiffies; + + bfq_weights_tree_remove(bfqd, &bfqq->entity, + &bfqd->queue_weights_tree); + } + + now_ns = ktime_get_ns(); + + bfqq->ttime.last_end_request = now_ns; + + /* + * Using us instead of ns, to get a reasonable precision in + * computing rate in next check. + */ + delta_us = div_u64(now_ns - bfqd->last_completion, NSEC_PER_USEC); + + bfq_log_bfqq(bfqd, bfqq, + "rq_completed: delta %uus/%luus max_size %u rate %llu/%llu", + delta_us, BFQ_MIN_TT/NSEC_PER_USEC, bfqd->last_rq_max_size, + (USEC_PER_SEC* + (u64)((bfqd->last_rq_max_size<>BFQ_RATE_SHIFT, + (USEC_PER_SEC*(u64)(1UL<<(BFQ_RATE_SHIFT-10)))>>BFQ_RATE_SHIFT); + + /* + * If the request took rather long to complete, and, according + * to the maximum request size recorded, this completion latency + * implies that the request was certainly served at a very low + * rate (less than 1M sectors/sec), then the whole observation + * interval that lasts up to this time instant cannot be a + * valid time interval for computing a new peak rate. Invoke + * bfq_update_rate_reset to have the following three steps + * taken: + * - close the observation interval at the last (previous) + * request dispatch or completion + * - compute rate, if possible, for that observation interval + * - reset to zero samples, which will trigger a proper + * re-initialization of the observation interval on next + * dispatch + */ + if (delta_us > BFQ_MIN_TT/NSEC_PER_USEC && + (bfqd->last_rq_max_size<last_completion = now_ns; + + /* + * If we are waiting to discover whether the request pattern + * of the task associated with the queue is actually + * isochronous, and both requisites for this condition to hold + * are now satisfied, then compute soft_rt_next_start (see the + * comments on the function bfq_bfqq_softrt_next_start()). We + * schedule this delayed check when bfqq expires, if it still + * has in-flight requests. + */ + if (bfq_bfqq_softrt_update(bfqq) && bfqq->dispatched == 0 && + RB_EMPTY_ROOT(&bfqq->sort_list)) + bfqq->soft_rt_next_start = + bfq_bfqq_softrt_next_start(bfqd, bfqq); + + /* + * If this is the in-service queue, check if it needs to be expired, + * or if we want to idle in case it has no pending requests. + */ + if (bfqd->in_service_queue == bfqq) { + if (bfqq->dispatched == 0 && bfq_bfqq_must_idle(bfqq)) { + bfq_arm_slice_timer(bfqd); + return; + } else if (bfq_may_expire_for_budg_timeout(bfqq)) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); + else if (RB_EMPTY_ROOT(&bfqq->sort_list) && + (bfqq->dispatched == 0 || + !bfq_bfqq_may_idle(bfqq))) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_NO_MORE_REQUESTS); + } +} + +static void bfq_put_rq_priv_body(struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqq->bfqd, bfqq, + "put_request_body: allocated %d", bfqq->allocated); + BUG_ON(!bfqq->allocated); + bfqq->allocated--; + + bfq_put_queue(bfqq); +} + +static void bfq_finish_request(struct request *rq) +{ + struct bfq_queue *bfqq; + struct bfq_data *bfqd; + struct bfq_io_cq *bic; + + BUG_ON(!rq); + + if (!rq->elv.icq) + return; + + bfqq = RQ_BFQQ(rq); + BUG_ON(!bfqq); + + bic = RQ_BIC(rq); + BUG_ON(!bic); + + bfqd = bfqq->bfqd; + BUG_ON(!bfqd); + + if (rq->rq_flags & RQF_DISP_LIST) { + pr_crit("putting disp rq %p for %d", rq, bfqq->pid); + BUG(); + } + BUG_ON(rq->rq_flags & RQF_QUEUED); + BUG_ON(!(rq->rq_flags & RQF_ELVPRIV)); + + bfq_log_bfqq(bfqd, bfqq, + "putting rq %p with %u sects left, STARTED %d", + rq, blk_rq_sectors(rq), + rq->rq_flags & RQF_STARTED); + + if (rq->rq_flags & RQF_STARTED) + bfqg_stats_update_completion(bfqq_group(bfqq), + rq_start_time_ns(rq), + rq_io_start_time_ns(rq), + rq->cmd_flags); + + BUG_ON(blk_rq_sectors(rq) == 0 && !(rq->rq_flags & RQF_STARTED)); + + if (likely(rq->rq_flags & RQF_STARTED)) { + unsigned long flags; + + spin_lock_irqsave(&bfqd->lock, flags); + + bfq_completed_request(bfqq, bfqd); + bfq_put_rq_priv_body(bfqq); + + spin_unlock_irqrestore(&bfqd->lock, flags); + } else { + /* + * Request rq may be still/already in the scheduler, + * in which case we need to remove it. And we cannot + * defer such a check and removal, to avoid + * inconsistencies in the time interval from the end + * of this function to the start of the deferred work. + * This situation seems to occur only in process + * context, as a consequence of a merge. In the + * current version of the code, this implies that the + * lock is held. + */ + BUG_ON(in_interrupt()); + + assert_spin_locked(&bfqd->lock); + if (!RB_EMPTY_NODE(&rq->rb_node)) + bfq_remove_request(rq->q, rq); + bfq_put_rq_priv_body(bfqq); + } + + rq->elv.priv[0] = NULL; + rq->elv.priv[1] = NULL; +} + +/* + * Returns NULL if a new bfqq should be allocated, or the old bfqq if this + * was the last process referring to that bfqq. + */ +static struct bfq_queue * +bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqq->bfqd, bfqq, "splitting queue"); + + if (bfqq_process_refs(bfqq) == 1) { + bfqq->pid = current->pid; + bfq_clear_bfqq_coop(bfqq); + bfq_clear_bfqq_split_coop(bfqq); + return bfqq; + } + + bic_set_bfqq(bic, NULL, 1); + + bfq_put_cooperator(bfqq); + + bfq_put_queue(bfqq); + return NULL; +} + +static struct bfq_queue *bfq_get_bfqq_handle_split(struct bfq_data *bfqd, + struct bfq_io_cq *bic, + struct bio *bio, + bool split, bool is_sync, + bool *new_queue) +{ + struct bfq_queue *bfqq = bic_to_bfqq(bic, is_sync); + + if (likely(bfqq && bfqq != &bfqd->oom_bfqq)) + return bfqq; + + if (new_queue) + *new_queue = true; + + if (bfqq) + bfq_put_queue(bfqq); + bfqq = bfq_get_queue(bfqd, bio, is_sync, bic); + BUG_ON(!hlist_unhashed(&bfqq->burst_list_node)); + + bic_set_bfqq(bic, bfqq, is_sync); + if (split && is_sync) { + bfq_log_bfqq(bfqd, bfqq, + "get_request: was_in_list %d " + "was_in_large_burst %d " + "large burst in progress %d", + bic->was_in_burst_list, + bic->saved_in_large_burst, + bfqd->large_burst); + + if ((bic->was_in_burst_list && bfqd->large_burst) || + bic->saved_in_large_burst) { + bfq_log_bfqq(bfqd, bfqq, + "get_request: marking in " + "large burst"); + bfq_mark_bfqq_in_large_burst(bfqq); + } else { + bfq_log_bfqq(bfqd, bfqq, + "get_request: clearing in " + "large burst"); + bfq_clear_bfqq_in_large_burst(bfqq); + if (bic->was_in_burst_list) + hlist_add_head(&bfqq->burst_list_node, + &bfqd->burst_list); + } + bfqq->split_time = jiffies; + } + + return bfqq; +} + +/* + * Allocate bfq data structures associated with this request. + */ +static void bfq_prepare_request(struct request *rq, struct bio *bio) +{ + struct request_queue *q = rq->q; + struct bfq_data *bfqd = q->elevator->elevator_data; + struct bfq_io_cq *bic; + const int is_sync = rq_is_sync(rq); + struct bfq_queue *bfqq; + bool bfqq_already_existing = false, split = false; + bool new_queue = false; + + if (!rq->elv.icq) + return; + bic = icq_to_bic(rq->elv.icq); + + spin_lock_irq(&bfqd->lock); + + bfq_check_ioprio_change(bic, bio); + + bfq_bic_update_cgroup(bic, bio); + + bfqq = bfq_get_bfqq_handle_split(bfqd, bic, bio, false, is_sync, + &new_queue); + + if (likely(!new_queue)) { + /* If the queue was seeky for too long, break it apart. */ + if (bfq_bfqq_coop(bfqq) && bfq_bfqq_split_coop(bfqq)) { + BUG_ON(!is_sync); + bfq_log_bfqq(bfqd, bfqq, "breaking apart bfqq"); + + /* Update bic before losing reference to bfqq */ + if (bfq_bfqq_in_large_burst(bfqq)) + bic->saved_in_large_burst = true; + + bfqq = bfq_split_bfqq(bic, bfqq); + + if (!bfqq) + bfqq = bfq_get_bfqq_handle_split(bfqd, bic, bio, + true, is_sync, + NULL); + else + bfqq_already_existing = true; + + BUG_ON(!bfqq); + BUG_ON(bfqq == &bfqd->oom_bfqq); + } + } + + bfqq->allocated++; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "get_request: new allocated %d", bfqq->allocated); + + bfqq->ref++; + bfq_log_bfqq(bfqd, bfqq, "get_request %p: bfqq %p, %d", rq, bfqq, bfqq->ref); + + rq->elv.priv[0] = bic; + rq->elv.priv[1] = bfqq; + rq->rq_flags &= ~RQF_DISP_LIST; + + /* + * If a bfq_queue has only one process reference, it is owned + * by only this bic: we can then set bfqq->bic = bic. in + * addition, if the queue has also just been split, we have to + * resume its state. + */ + if (likely(bfqq != &bfqd->oom_bfqq) && bfqq_process_refs(bfqq) == 1) { + bfqq->bic = bic; + if (split) { + /* + * The queue has just been split from a shared + * queue: restore the idle window and the + * possible weight raising period. + */ + bfq_bfqq_resume_state(bfqq, bfqd, bic, + bfqq_already_existing); + } + } + + if (unlikely(bfq_bfqq_just_created(bfqq))) + bfq_handle_burst(bfqd, bfqq); + + rq->rq_flags |= RQF_GOT; + spin_unlock_irq(&bfqd->lock); +} + +static void bfq_idle_slice_timer_body(struct bfq_queue *bfqq) +{ + struct bfq_data *bfqd = bfqq->bfqd; + enum bfqq_expiration reason; + unsigned long flags; + + BUG_ON(!bfqd); + spin_lock_irqsave(&bfqd->lock, flags); + + bfq_log_bfqq(bfqd, bfqq, "handling slice_timer expiration"); + bfq_clear_bfqq_wait_request(bfqq); + + if (bfqq != bfqd->in_service_queue) { + spin_unlock_irqrestore(&bfqd->lock, flags); + return; + } + + if (bfq_bfqq_budget_timeout(bfqq)) + /* + * Also here the queue can be safely expired + * for budget timeout without wasting + * guarantees + */ + reason = BFQ_BFQQ_BUDGET_TIMEOUT; + else if (bfqq->queued[0] == 0 && bfqq->queued[1] == 0) + /* + * The queue may not be empty upon timer expiration, + * because we may not disable the timer when the + * first request of the in-service queue arrives + * during disk idling. + */ + reason = BFQ_BFQQ_TOO_IDLE; + else + goto schedule_dispatch; + + bfq_bfqq_expire(bfqd, bfqq, true, reason); + +schedule_dispatch: + spin_unlock_irqrestore(&bfqd->lock, flags); + bfq_schedule_dispatch(bfqd); +} + +/* + * Handler of the expiration of the timer running if the in-service queue + * is idling inside its time slice. + */ +static enum hrtimer_restart bfq_idle_slice_timer(struct hrtimer *timer) +{ + struct bfq_data *bfqd = container_of(timer, struct bfq_data, + idle_slice_timer); + struct bfq_queue *bfqq = bfqd->in_service_queue; + + bfq_log(bfqd, "slice_timer expired"); + + /* + * Theoretical race here: the in-service queue can be NULL or + * different from the queue that was idling if a new request + * arrives for the current queue and there is a full dispatch + * cycle that changes the in-service queue. This can hardly + * happen, but in the worst case we just expire a queue too + * early. + */ + if (bfqq) + bfq_idle_slice_timer_body(bfqq); + + return HRTIMER_NORESTART; +} + +static void __bfq_put_async_bfqq(struct bfq_data *bfqd, + struct bfq_queue **bfqq_ptr) +{ + struct bfq_group *root_group = bfqd->root_group; + struct bfq_queue *bfqq = *bfqq_ptr; + + bfq_log(bfqd, "put_async_bfqq: %p", bfqq); + if (bfqq) { + bfq_bfqq_move(bfqd, bfqq, root_group); + bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d", + bfqq, bfqq->ref); + bfq_put_queue(bfqq); + *bfqq_ptr = NULL; + } +} + +/* + * Release all the bfqg references to its async queues. If we are + * deallocating the group these queues may still contain requests, so + * we reparent them to the root cgroup (i.e., the only one that will + * exist for sure until all the requests on a device are gone). + */ +static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) +{ + int i, j; + + for (i = 0; i < 2; i++) + for (j = 0; j < IOPRIO_BE_NR; j++) + __bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]); + + __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq); +} + +static void bfq_exit_queue(struct elevator_queue *e) +{ + struct bfq_data *bfqd = e->elevator_data; + struct bfq_queue *bfqq, *n; + + bfq_log(bfqd, "exit_queue: starting ..."); + + hrtimer_cancel(&bfqd->idle_slice_timer); + + BUG_ON(bfqd->in_service_queue); + BUG_ON(!list_empty(&bfqd->active_list)); + + spin_lock_irq(&bfqd->lock); + list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list) + bfq_deactivate_bfqq(bfqd, bfqq, false, false); + spin_unlock_irq(&bfqd->lock); + + hrtimer_cancel(&bfqd->idle_slice_timer); + + BUG_ON(hrtimer_active(&bfqd->idle_slice_timer)); + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_deactivate_policy(bfqd->queue, &blkcg_policy_bfq); +#else + spin_lock_irq(&bfqd->lock); + bfq_put_async_queues(bfqd, bfqd->root_group); + kfree(bfqd->root_group); + spin_unlock_irq(&bfqd->lock); +#endif + + bfq_log(bfqd, "exit_queue: finished ..."); + kfree(bfqd); +} + +static void bfq_init_root_group(struct bfq_group *root_group, + struct bfq_data *bfqd) +{ + int i; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + root_group->entity.parent = NULL; + root_group->my_entity = NULL; + root_group->bfqd = bfqd; +#endif + root_group->rq_pos_tree = RB_ROOT; + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) + root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; + root_group->sched_data.bfq_class_idle_last_service = jiffies; +} + +static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) +{ + struct bfq_data *bfqd; + struct elevator_queue *eq; + + eq = elevator_alloc(q, e); + if (!eq) + return -ENOMEM; + + bfqd = kzalloc_node(sizeof(*bfqd), GFP_KERNEL, q->node); + if (!bfqd) { + kobject_put(&eq->kobj); + return -ENOMEM; + } + eq->elevator_data = bfqd; + + spin_lock_irq(q->queue_lock); + q->elevator = eq; + spin_unlock_irq(q->queue_lock); + + /* + * Our fallback bfqq if bfq_find_alloc_queue() runs into OOM issues. + * Grab a permanent reference to it, so that the normal code flow + * will not attempt to free it. + */ + bfq_init_bfqq(bfqd, &bfqd->oom_bfqq, NULL, 1, 0); + bfqd->oom_bfqq.ref++; + bfqd->oom_bfqq.new_ioprio = BFQ_DEFAULT_QUEUE_IOPRIO; + bfqd->oom_bfqq.new_ioprio_class = IOPRIO_CLASS_BE; + bfqd->oom_bfqq.entity.new_weight = + bfq_ioprio_to_weight(bfqd->oom_bfqq.new_ioprio); + + /* oom_bfqq does not participate to bursts */ + bfq_clear_bfqq_just_created(&bfqd->oom_bfqq); + /* + * Trigger weight initialization, according to ioprio, at the + * oom_bfqq's first activation. The oom_bfqq's ioprio and ioprio + * class won't be changed any more. + */ + bfqd->oom_bfqq.entity.prio_changed = 1; + + bfqd->queue = q; + INIT_LIST_HEAD(&bfqd->dispatch); + + hrtimer_init(&bfqd->idle_slice_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + bfqd->idle_slice_timer.function = bfq_idle_slice_timer; + + bfqd->queue_weights_tree = RB_ROOT; + bfqd->group_weights_tree = RB_ROOT; + + INIT_LIST_HEAD(&bfqd->active_list); + INIT_LIST_HEAD(&bfqd->idle_list); + INIT_HLIST_HEAD(&bfqd->burst_list); + + bfqd->hw_tag = -1; + + bfqd->bfq_max_budget = bfq_default_max_budget; + + bfqd->bfq_fifo_expire[0] = bfq_fifo_expire[0]; + bfqd->bfq_fifo_expire[1] = bfq_fifo_expire[1]; + bfqd->bfq_back_max = bfq_back_max; + bfqd->bfq_back_penalty = bfq_back_penalty; + bfqd->bfq_slice_idle = bfq_slice_idle; + bfqd->bfq_timeout = bfq_timeout; + + bfqd->bfq_requests_within_timer = 120; + + bfqd->bfq_large_burst_thresh = 8; + bfqd->bfq_burst_interval = msecs_to_jiffies(180); + + bfqd->low_latency = true; + + /* + * Trade-off between responsiveness and fairness. + */ + bfqd->bfq_wr_coeff = 30; + bfqd->bfq_wr_rt_max_time = msecs_to_jiffies(300); + bfqd->bfq_wr_max_time = 0; + bfqd->bfq_wr_min_idle_time = msecs_to_jiffies(2000); + bfqd->bfq_wr_min_inter_arr_async = msecs_to_jiffies(500); + bfqd->bfq_wr_max_softrt_rate = 7000; /* + * Approximate rate required + * to playback or record a + * high-definition compressed + * video. + */ + bfqd->wr_busy_queues = 0; + + /* + * Begin by assuming, optimistically, that the device is a + * high-speed one, and that its peak rate is equal to 2/3 of + * the highest reference rate. + */ + bfqd->RT_prod = R_fast[blk_queue_nonrot(bfqd->queue)] * + T_fast[blk_queue_nonrot(bfqd->queue)]; + bfqd->peak_rate = R_fast[blk_queue_nonrot(bfqd->queue)] * 2 / 3; + bfqd->device_speed = BFQ_BFQD_FAST; + + spin_lock_init(&bfqd->lock); + + /* + * The invocation of the next bfq_create_group_hierarchy + * function is the head of a chain of function calls + * (bfq_create_group_hierarchy->blkcg_activate_policy-> + * blk_mq_freeze_queue) that may lead to the invocation of the + * has_work hook function. For this reason, + * bfq_create_group_hierarchy is invoked only after all + * scheduler data has been initialized, apart from the fields + * that can be initialized only after invoking + * bfq_create_group_hierarchy. This, in particular, enables + * has_work to correctly return false. Of course, to avoid + * other inconsistencies, the blk-mq stack must then refrain + * from invoking further scheduler hooks before this init + * function is finished. + */ + bfqd->root_group = bfq_create_group_hierarchy(bfqd, q->node); + if (!bfqd->root_group) + goto out_free; + bfq_init_root_group(bfqd->root_group, bfqd); + bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group); + + return 0; + +out_free: + kfree(bfqd); + kobject_put(&eq->kobj); + return -ENOMEM; +} + +static void bfq_slab_kill(void) +{ + kmem_cache_destroy(bfq_pool); +} + +static int __init bfq_slab_setup(void) +{ + bfq_pool = KMEM_CACHE(bfq_queue, 0); + if (!bfq_pool) + return -ENOMEM; + return 0; +} + +static ssize_t bfq_var_show(unsigned int var, char *page) +{ + return sprintf(page, "%u\n", var); +} + +static ssize_t bfq_var_store(unsigned long *var, const char *page, + size_t count) +{ + unsigned long new_val; + int ret = kstrtoul(page, 10, &new_val); + + if (ret == 0) + *var = new_val; + + return count; +} + +static ssize_t bfq_wr_max_time_show(struct elevator_queue *e, char *page) +{ + struct bfq_data *bfqd = e->elevator_data; + + return sprintf(page, "%d\n", bfqd->bfq_wr_max_time > 0 ? + jiffies_to_msecs(bfqd->bfq_wr_max_time) : + jiffies_to_msecs(bfq_wr_duration(bfqd))); +} + +static ssize_t bfq_weights_show(struct elevator_queue *e, char *page) +{ + struct bfq_queue *bfqq; + struct bfq_data *bfqd = e->elevator_data; + ssize_t num_char = 0; + + num_char += sprintf(page + num_char, "Tot reqs queued %d\n\n", + bfqd->queued); + + spin_lock_irq(&bfqd->lock); + + num_char += sprintf(page + num_char, "Active:\n"); + list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) { + num_char += sprintf(page + num_char, + "pid%d: weight %hu, nr_queued %d %d, ", + bfqq->pid, + bfqq->entity.weight, + bfqq->queued[0], + bfqq->queued[1]); + num_char += sprintf(page + num_char, + "dur %d/%u\n", + jiffies_to_msecs( + jiffies - + bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + num_char += sprintf(page + num_char, "Idle:\n"); + list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) { + num_char += sprintf(page + num_char, + "pid%d: weight %hu, dur %d/%u\n", + bfqq->pid, + bfqq->entity.weight, + jiffies_to_msecs(jiffies - + bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + spin_unlock_irq(&bfqd->lock); + + return num_char; +} + +#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ +static ssize_t __FUNC(struct elevator_queue *e, char *page) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + u64 __data = __VAR; \ + if (__CONV == 1) \ + __data = jiffies_to_msecs(__data); \ + else if (__CONV == 2) \ + __data = div_u64(__data, NSEC_PER_MSEC); \ + return bfq_var_show(__data, (page)); \ +} +SHOW_FUNCTION(bfq_fifo_expire_sync_show, bfqd->bfq_fifo_expire[1], 2); +SHOW_FUNCTION(bfq_fifo_expire_async_show, bfqd->bfq_fifo_expire[0], 2); +SHOW_FUNCTION(bfq_back_seek_max_show, bfqd->bfq_back_max, 0); +SHOW_FUNCTION(bfq_back_seek_penalty_show, bfqd->bfq_back_penalty, 0); +SHOW_FUNCTION(bfq_slice_idle_show, bfqd->bfq_slice_idle, 2); +SHOW_FUNCTION(bfq_max_budget_show, bfqd->bfq_user_max_budget, 0); +SHOW_FUNCTION(bfq_timeout_sync_show, bfqd->bfq_timeout, 1); +SHOW_FUNCTION(bfq_strict_guarantees_show, bfqd->strict_guarantees, 0); +SHOW_FUNCTION(bfq_low_latency_show, bfqd->low_latency, 0); +SHOW_FUNCTION(bfq_wr_coeff_show, bfqd->bfq_wr_coeff, 0); +SHOW_FUNCTION(bfq_wr_rt_max_time_show, bfqd->bfq_wr_rt_max_time, 1); +SHOW_FUNCTION(bfq_wr_min_idle_time_show, bfqd->bfq_wr_min_idle_time, 1); +SHOW_FUNCTION(bfq_wr_min_inter_arr_async_show, bfqd->bfq_wr_min_inter_arr_async, + 1); +SHOW_FUNCTION(bfq_wr_max_softrt_rate_show, bfqd->bfq_wr_max_softrt_rate, 0); +#undef SHOW_FUNCTION + +#define USEC_SHOW_FUNCTION(__FUNC, __VAR) \ +static ssize_t __FUNC(struct elevator_queue *e, char *page) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + u64 __data = __VAR; \ + __data = div_u64(__data, NSEC_PER_USEC); \ + return bfq_var_show(__data, (page)); \ +} +USEC_SHOW_FUNCTION(bfq_slice_idle_us_show, bfqd->bfq_slice_idle); +#undef USEC_SHOW_FUNCTION + +#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ +static ssize_t \ +__FUNC(struct elevator_queue *e, const char *page, size_t count) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + unsigned long uninitialized_var(__data); \ + int ret = bfq_var_store(&__data, (page), count); \ + if (__data < (MIN)) \ + __data = (MIN); \ + else if (__data > (MAX)) \ + __data = (MAX); \ + if (__CONV == 1) \ + *(__PTR) = msecs_to_jiffies(__data); \ + else if (__CONV == 2) \ + *(__PTR) = (u64)__data * NSEC_PER_MSEC; \ + else \ + *(__PTR) = __data; \ + return ret; \ +} +STORE_FUNCTION(bfq_fifo_expire_sync_store, &bfqd->bfq_fifo_expire[1], 1, + INT_MAX, 2); +STORE_FUNCTION(bfq_fifo_expire_async_store, &bfqd->bfq_fifo_expire[0], 1, + INT_MAX, 2); +STORE_FUNCTION(bfq_back_seek_max_store, &bfqd->bfq_back_max, 0, INT_MAX, 0); +STORE_FUNCTION(bfq_back_seek_penalty_store, &bfqd->bfq_back_penalty, 1, + INT_MAX, 0); +STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 2); +STORE_FUNCTION(bfq_wr_coeff_store, &bfqd->bfq_wr_coeff, 1, INT_MAX, 0); +STORE_FUNCTION(bfq_wr_max_time_store, &bfqd->bfq_wr_max_time, 0, INT_MAX, 1); +STORE_FUNCTION(bfq_wr_rt_max_time_store, &bfqd->bfq_wr_rt_max_time, 0, INT_MAX, + 1); +STORE_FUNCTION(bfq_wr_min_idle_time_store, &bfqd->bfq_wr_min_idle_time, 0, + INT_MAX, 1); +STORE_FUNCTION(bfq_wr_min_inter_arr_async_store, + &bfqd->bfq_wr_min_inter_arr_async, 0, INT_MAX, 1); +STORE_FUNCTION(bfq_wr_max_softrt_rate_store, &bfqd->bfq_wr_max_softrt_rate, 0, + INT_MAX, 0); +#undef STORE_FUNCTION + +#define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \ +static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)\ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + unsigned long uninitialized_var(__data); \ + int ret = bfq_var_store(&__data, (page), count); \ + if (__data < (MIN)) \ + __data = (MIN); \ + else if (__data > (MAX)) \ + __data = (MAX); \ + *(__PTR) = (u64)__data * NSEC_PER_USEC; \ + return ret; \ +} +USEC_STORE_FUNCTION(bfq_slice_idle_us_store, &bfqd->bfq_slice_idle, 0, + UINT_MAX); +#undef USEC_STORE_FUNCTION + +/* do nothing for the moment */ +static ssize_t bfq_weights_store(struct elevator_queue *e, + const char *page, size_t count) +{ + return count; +} + +static ssize_t bfq_max_budget_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data == 0) + bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd); + else { + if (__data > INT_MAX) + __data = INT_MAX; + bfqd->bfq_max_budget = __data; + } + + bfqd->bfq_user_max_budget = __data; + + return ret; +} + +/* + * Leaving this name to preserve name compatibility with cfq + * parameters, but this timeout is used for both sync and async. + */ +static ssize_t bfq_timeout_sync_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data < 1) + __data = 1; + else if (__data > INT_MAX) + __data = INT_MAX; + + bfqd->bfq_timeout = msecs_to_jiffies(__data); + if (bfqd->bfq_user_max_budget == 0) + bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd); + + return ret; +} + +static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data > 1) + __data = 1; + if (!bfqd->strict_guarantees && __data == 1 + && bfqd->bfq_slice_idle < 8 * NSEC_PER_MSEC) + bfqd->bfq_slice_idle = 8 * NSEC_PER_MSEC; + + bfqd->strict_guarantees = __data; + + return ret; +} + +static ssize_t bfq_low_latency_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data > 1) + __data = 1; + if (__data == 0 && bfqd->low_latency != 0) + bfq_end_wr(bfqd); + bfqd->low_latency = __data; + + return ret; +} + +#define BFQ_ATTR(name) \ + __ATTR(name, S_IRUGO|S_IWUSR, bfq_##name##_show, bfq_##name##_store) + +static struct elv_fs_entry bfq_attrs[] = { + BFQ_ATTR(fifo_expire_sync), + BFQ_ATTR(fifo_expire_async), + BFQ_ATTR(back_seek_max), + BFQ_ATTR(back_seek_penalty), + BFQ_ATTR(slice_idle), + BFQ_ATTR(slice_idle_us), + BFQ_ATTR(max_budget), + BFQ_ATTR(timeout_sync), + BFQ_ATTR(strict_guarantees), + BFQ_ATTR(low_latency), + BFQ_ATTR(wr_coeff), + BFQ_ATTR(wr_max_time), + BFQ_ATTR(wr_rt_max_time), + BFQ_ATTR(wr_min_idle_time), + BFQ_ATTR(wr_min_inter_arr_async), + BFQ_ATTR(wr_max_softrt_rate), + BFQ_ATTR(weights), + __ATTR_NULL +}; + +static struct elevator_type iosched_bfq_mq = { + .ops.mq = { + .prepare_request = bfq_prepare_request, + .finish_request = bfq_finish_request, + .exit_icq = bfq_exit_icq, + .insert_requests = bfq_insert_requests, + .dispatch_request = bfq_dispatch_request, + .next_request = elv_rb_latter_request, + .former_request = elv_rb_former_request, + .allow_merge = bfq_allow_bio_merge, + .bio_merge = bfq_bio_merge, + .request_merge = bfq_request_merge, + .requests_merged = bfq_requests_merged, + .request_merged = bfq_request_merged, + .has_work = bfq_has_work, + .init_sched = bfq_init_queue, + .exit_sched = bfq_exit_queue, + }, + + .uses_mq = true, + .icq_size = sizeof(struct bfq_io_cq), + .icq_align = __alignof__(struct bfq_io_cq), + .elevator_attrs = bfq_attrs, + .elevator_name = "bfq-mq", + .elevator_owner = THIS_MODULE, +}; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct blkcg_policy blkcg_policy_bfq = { + .dfl_cftypes = bfq_blkg_files, + .legacy_cftypes = bfq_blkcg_legacy_files, + + .cpd_alloc_fn = bfq_cpd_alloc, + .cpd_init_fn = bfq_cpd_init, + .cpd_bind_fn = bfq_cpd_init, + .cpd_free_fn = bfq_cpd_free, + + .pd_alloc_fn = bfq_pd_alloc, + .pd_init_fn = bfq_pd_init, + .pd_offline_fn = bfq_pd_offline, + .pd_free_fn = bfq_pd_free, + .pd_reset_stats_fn = bfq_pd_reset_stats, +}; +#endif + +static int __init bfq_init(void) +{ + int ret; + char msg[60] = "BFQ I/O-scheduler: v8r12"; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + ret = blkcg_policy_register(&blkcg_policy_bfq); + if (ret) + return ret; +#endif + + ret = -ENOMEM; + if (bfq_slab_setup()) + goto err_pol_unreg; + + /* + * Times to load large popular applications for the typical + * systems installed on the reference devices (see the + * comments before the definitions of the next two + * arrays). Actually, we use slightly slower values, as the + * estimated peak rate tends to be smaller than the actual + * peak rate. The reason for this last fact is that estimates + * are computed over much shorter time intervals than the long + * intervals typically used for benchmarking. Why? First, to + * adapt more quickly to variations. Second, because an I/O + * scheduler cannot rely on a peak-rate-evaluation workload to + * be run for a long time. + */ + T_slow[0] = msecs_to_jiffies(3500); /* actually 4 sec */ + T_slow[1] = msecs_to_jiffies(6000); /* actually 6.5 sec */ + T_fast[0] = msecs_to_jiffies(7000); /* actually 8 sec */ + T_fast[1] = msecs_to_jiffies(2500); /* actually 3 sec */ + + /* + * Thresholds that determine the switch between speed classes + * (see the comments before the definition of the array + * device_speed_thresh). These thresholds are biased towards + * transitions to the fast class. This is safer than the + * opposite bias. In fact, a wrong transition to the slow + * class results in short weight-raising periods, because the + * speed of the device then tends to be higher that the + * reference peak rate. On the opposite end, a wrong + * transition to the fast class tends to increase + * weight-raising periods, because of the opposite reason. + */ + device_speed_thresh[0] = (4 * R_slow[0]) / 3; + device_speed_thresh[1] = (4 * R_slow[1]) / 3; + + ret = elv_register(&iosched_bfq_mq); + if (ret) + goto err_pol_unreg; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + strcat(msg, " (with cgroups support)"); +#endif + pr_info("%s", msg); + + return 0; + +err_pol_unreg: +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif + return ret; +} + +static void __exit bfq_exit(void) +{ + elv_unregister(&iosched_bfq_mq); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif + bfq_slab_kill(); +} + +module_init(bfq_init); +module_exit(bfq_exit); + +MODULE_AUTHOR("Paolo Valente"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("MQ Budget Fair Queueing I/O Scheduler"); diff --git b/block/bfq-mq.h b/block/bfq-mq.h new file mode 100644 index 0000000..7ed2cc2 --- /dev/null +++ b/block/bfq-mq.h @@ -0,0 +1,987 @@ +/* + * BFQ v8r12 for 4.11.0: data structures and common functions prototypes. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2017 Paolo Valente + */ + +#ifndef _BFQ_H +#define _BFQ_H + +#include +#include + +/* see comments on CONFIG_BFQ_GROUP_IOSCHED in bfq.h */ +#ifdef CONFIG_MQ_BFQ_GROUP_IOSCHED +#define BFQ_GROUP_IOSCHED_ENABLED +#endif + +#define BFQ_IOPRIO_CLASSES 3 +#define BFQ_CL_IDLE_TIMEOUT (HZ/5) + +#define BFQ_MIN_WEIGHT 1 +#define BFQ_MAX_WEIGHT 1000 +#define BFQ_WEIGHT_CONVERSION_COEFF 10 + +#define BFQ_DEFAULT_QUEUE_IOPRIO 4 + +#define BFQ_WEIGHT_LEGACY_DFL 100 +#define BFQ_DEFAULT_GRP_IOPRIO 0 +#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE + +/* + * Soft real-time applications are extremely more latency sensitive + * than interactive ones. Over-raise the weight of the former to + * privilege them against the latter. + */ +#define BFQ_SOFTRT_WEIGHT_FACTOR 100 + +struct bfq_entity; + +/** + * struct bfq_service_tree - per ioprio_class service tree. + * + * Each service tree represents a B-WF2Q+ scheduler on its own. Each + * ioprio_class has its own independent scheduler, and so its own + * bfq_service_tree. All the fields are protected by the queue lock + * of the containing bfqd. + */ +struct bfq_service_tree { + /* tree for active entities (i.e., those backlogged) */ + struct rb_root active; + /* tree for idle entities (i.e., not backlogged, with V <= F_i)*/ + struct rb_root idle; + + struct bfq_entity *first_idle; /* idle entity with minimum F_i */ + struct bfq_entity *last_idle; /* idle entity with maximum F_i */ + + u64 vtime; /* scheduler virtual time */ + /* scheduler weight sum; active and idle entities contribute to it */ + unsigned long wsum; +}; + +/** + * struct bfq_sched_data - multi-class scheduler. + * + * bfq_sched_data is the basic scheduler queue. It supports three + * ioprio_classes, and can be used either as a toplevel queue or as an + * intermediate queue in a hierarchical setup. + * + * The supported ioprio_classes are the same as in CFQ, in descending + * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE. + * Requests from higher priority queues are served before all the + * requests from lower priority queues; among requests of the same + * queue requests are served according to B-WF2Q+. + * + * The schedule is implemented by the service trees, plus the field + * @next_in_service, which points to the entity on the active trees + * that will be served next, if 1) no changes in the schedule occurs + * before the current in-service entity is expired, 2) the in-service + * queue becomes idle when it expires, and 3) if the entity pointed by + * in_service_entity is not a queue, then the in-service child entity + * of the entity pointed by in_service_entity becomes idle on + * expiration. This peculiar definition allows for the following + * optimization, not yet exploited: while a given entity is still in + * service, we already know which is the best candidate for next + * service among the other active entitities in the same parent + * entity. We can then quickly compare the timestamps of the + * in-service entity with those of such best candidate. + * + * All the fields are protected by the queue lock of the containing + * bfqd. + */ +struct bfq_sched_data { + struct bfq_entity *in_service_entity; /* entity in service */ + /* head-of-the-line entity in the scheduler (see comments above) */ + struct bfq_entity *next_in_service; + /* array of service trees, one per ioprio_class */ + struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES]; + /* last time CLASS_IDLE was served */ + unsigned long bfq_class_idle_last_service; + +}; + +/** + * struct bfq_weight_counter - counter of the number of all active entities + * with a given weight. + */ +struct bfq_weight_counter { + unsigned int weight; /* weight of the entities this counter refers to */ + unsigned int num_active; /* nr of active entities with this weight */ + /* + * Weights tree member (see bfq_data's @queue_weights_tree and + * @group_weights_tree) + */ + struct rb_node weights_node; +}; + +/** + * struct bfq_entity - schedulable entity. + * + * A bfq_entity is used to represent either a bfq_queue (leaf node in the + * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each + * entity belongs to the sched_data of the parent group in the cgroup + * hierarchy. Non-leaf entities have also their own sched_data, stored + * in @my_sched_data. + * + * Each entity stores independently its priority values; this would + * allow different weights on different devices, but this + * functionality is not exported to userspace by now. Priorities and + * weights are updated lazily, first storing the new values into the + * new_* fields, then setting the @prio_changed flag. As soon as + * there is a transition in the entity state that allows the priority + * update to take place the effective and the requested priority + * values are synchronized. + * + * Unless cgroups are used, the weight value is calculated from the + * ioprio to export the same interface as CFQ. When dealing with + * ``well-behaved'' queues (i.e., queues that do not spend too much + * time to consume their budget and have true sequential behavior, and + * when there are no external factors breaking anticipation) the + * relative weights at each level of the cgroups hierarchy should be + * guaranteed. All the fields are protected by the queue lock of the + * containing bfqd. + */ +struct bfq_entity { + struct rb_node rb_node; /* service_tree member */ + /* pointer to the weight counter associated with this entity */ + struct bfq_weight_counter *weight_counter; + + /* + * Flag, true if the entity is on a tree (either the active or + * the idle one of its service_tree) or is in service. + */ + bool on_st; + + u64 finish; /* B-WF2Q+ finish timestamp (aka F_i) */ + u64 start; /* B-WF2Q+ start timestamp (aka S_i) */ + + /* tree the entity is enqueued into; %NULL if not on a tree */ + struct rb_root *tree; + + /* + * minimum start time of the (active) subtree rooted at this + * entity; used for O(log N) lookups into active trees + */ + u64 min_start; + + /* amount of service received during the last service slot */ + int service; + + /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ + int budget; + + unsigned int weight; /* weight of the queue */ + unsigned int new_weight; /* next weight if a change is in progress */ + + /* original weight, used to implement weight boosting */ + unsigned int orig_weight; + + /* parent entity, for hierarchical scheduling */ + struct bfq_entity *parent; + + /* + * For non-leaf nodes in the hierarchy, the associated + * scheduler queue, %NULL on leaf nodes. + */ + struct bfq_sched_data *my_sched_data; + /* the scheduler queue this entity belongs to */ + struct bfq_sched_data *sched_data; + + /* flag, set to request a weight, ioprio or ioprio_class change */ + int prio_changed; +}; + +struct bfq_group; + +/** + * struct bfq_ttime - per process thinktime stats. + */ +struct bfq_ttime { + u64 last_end_request; /* completion time of last request */ + + u64 ttime_total; /* total process thinktime */ + unsigned long ttime_samples; /* number of thinktime samples */ + u64 ttime_mean; /* average process thinktime */ + +}; + +/** + * struct bfq_queue - leaf schedulable entity. + * + * A bfq_queue is a leaf request queue; it can be associated with an + * io_context or more, if it is async or shared between cooperating + * processes. @cgroup holds a reference to the cgroup, to be sure that it + * does not disappear while a bfqq still references it (mostly to avoid + * races between request issuing and task migration followed by cgroup + * destruction). + * All the fields are protected by the queue lock of the containing bfqd. + */ +struct bfq_queue { + /* reference counter */ + int ref; + /* parent bfq_data */ + struct bfq_data *bfqd; + + /* current ioprio and ioprio class */ + unsigned short ioprio, ioprio_class; + /* next ioprio and ioprio class if a change is in progress */ + unsigned short new_ioprio, new_ioprio_class; + + /* + * Shared bfq_queue if queue is cooperating with one or more + * other queues. + */ + struct bfq_queue *new_bfqq; + /* request-position tree member (see bfq_group's @rq_pos_tree) */ + struct rb_node pos_node; + /* request-position tree root (see bfq_group's @rq_pos_tree) */ + struct rb_root *pos_root; + + /* sorted list of pending requests */ + struct rb_root sort_list; + /* if fifo isn't expired, next request to serve */ + struct request *next_rq; + /* number of sync and async requests queued */ + int queued[2]; + /* number of requests currently allocated */ + int allocated; + /* number of pending metadata requests */ + int meta_pending; + /* fifo list of requests in sort_list */ + struct list_head fifo; + + /* entity representing this queue in the scheduler */ + struct bfq_entity entity; + + /* maximum budget allowed from the feedback mechanism */ + int max_budget; + /* budget expiration (in jiffies) */ + unsigned long budget_timeout; + + /* number of requests on the dispatch list or inside driver */ + int dispatched; + + unsigned int flags; /* status flags.*/ + + /* node for active/idle bfqq list inside parent bfqd */ + struct list_head bfqq_list; + + /* associated @bfq_ttime struct */ + struct bfq_ttime ttime; + + /* bit vector: a 1 for each seeky requests in history */ + u32 seek_history; + + /* node for the device's burst list */ + struct hlist_node burst_list_node; + + /* position of the last request enqueued */ + sector_t last_request_pos; + + /* Number of consecutive pairs of request completion and + * arrival, such that the queue becomes idle after the + * completion, but the next request arrives within an idle + * time slice; used only if the queue's IO_bound flag has been + * cleared. + */ + unsigned int requests_within_timer; + + /* pid of the process owning the queue, used for logging purposes */ + pid_t pid; + + /* + * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL + * if the queue is shared. + */ + struct bfq_io_cq *bic; + + /* current maximum weight-raising time for this queue */ + unsigned long wr_cur_max_time; + /* + * Minimum time instant such that, only if a new request is + * enqueued after this time instant in an idle @bfq_queue with + * no outstanding requests, then the task associated with the + * queue it is deemed as soft real-time (see the comments on + * the function bfq_bfqq_softrt_next_start()) + */ + unsigned long soft_rt_next_start; + /* + * Start time of the current weight-raising period if + * the @bfq-queue is being weight-raised, otherwise + * finish time of the last weight-raising period. + */ + unsigned long last_wr_start_finish; + /* factor by which the weight of this queue is multiplied */ + unsigned int wr_coeff; + /* + * Time of the last transition of the @bfq_queue from idle to + * backlogged. + */ + unsigned long last_idle_bklogged; + /* + * Cumulative service received from the @bfq_queue since the + * last transition from idle to backlogged. + */ + unsigned long service_from_backlogged; + /* + * Value of wr start time when switching to soft rt + */ + unsigned long wr_start_at_switch_to_srt; + + unsigned long split_time; /* time of last split */ +}; + +/** + * struct bfq_io_cq - per (request_queue, io_context) structure. + */ +struct bfq_io_cq { + /* associated io_cq structure */ + struct io_cq icq; /* must be the first member */ + /* array of two process queues, the sync and the async */ + struct bfq_queue *bfqq[2]; + /* per (request_queue, blkcg) ioprio */ + int ioprio; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + uint64_t blkcg_serial_nr; /* the current blkcg serial */ +#endif + + /* + * Snapshot of the has_short_time flag before merging; taken + * to remember its value while the queue is merged, so as to + * be able to restore it in case of split. + */ + bool saved_has_short_ttime; + /* + * Same purpose as the previous two fields for the I/O bound + * classification of a queue. + */ + bool saved_IO_bound; + + /* + * Same purpose as the previous fields for the value of the + * field keeping the queue's belonging to a large burst + */ + bool saved_in_large_burst; + /* + * True if the queue belonged to a burst list before its merge + * with another cooperating queue. + */ + bool was_in_burst_list; + + /* + * Similar to previous fields: save wr information. + */ + unsigned long saved_wr_coeff; + unsigned long saved_last_wr_start_finish; + unsigned long saved_wr_start_at_switch_to_srt; + unsigned int saved_wr_cur_max_time; + struct bfq_ttime saved_ttime; +}; + +enum bfq_device_speed { + BFQ_BFQD_FAST, + BFQ_BFQD_SLOW, +}; + +/** + * struct bfq_data - per-device data structure. + * + * All the fields are protected by @lock. + */ +struct bfq_data { + /* device request queue */ + struct request_queue *queue; + /* dispatch queue */ + struct list_head dispatch; + + /* root bfq_group for the device */ + struct bfq_group *root_group; + + /* + * rbtree of weight counters of @bfq_queues, sorted by + * weight. Used to keep track of whether all @bfq_queues have + * the same weight. The tree contains one counter for each + * distinct weight associated to some active and not + * weight-raised @bfq_queue (see the comments to the functions + * bfq_weights_tree_[add|remove] for further details). + */ + struct rb_root queue_weights_tree; + /* + * rbtree of non-queue @bfq_entity weight counters, sorted by + * weight. Used to keep track of whether all @bfq_groups have + * the same weight. The tree contains one counter for each + * distinct weight associated to some active @bfq_group (see + * the comments to the functions bfq_weights_tree_[add|remove] + * for further details). + */ + struct rb_root group_weights_tree; + + /* + * Number of bfq_queues containing requests (including the + * queue in service, even if it is idling). + */ + int busy_queues; + /* number of weight-raised busy @bfq_queues */ + int wr_busy_queues; + /* number of queued requests */ + int queued; + /* number of requests dispatched and waiting for completion */ + int rq_in_driver; + + /* + * Maximum number of requests in driver in the last + * @hw_tag_samples completed requests. + */ + int max_rq_in_driver; + /* number of samples used to calculate hw_tag */ + int hw_tag_samples; + /* flag set to one if the driver is showing a queueing behavior */ + int hw_tag; + + /* number of budgets assigned */ + int budgets_assigned; + + /* + * Timer set when idling (waiting) for the next request from + * the queue in service. + */ + struct hrtimer idle_slice_timer; + + /* bfq_queue in service */ + struct bfq_queue *in_service_queue; + + /* on-disk position of the last served request */ + sector_t last_position; + + /* time of last request completion (ns) */ + u64 last_completion; + + /* time of first rq dispatch in current observation interval (ns) */ + u64 first_dispatch; + /* time of last rq dispatch in current observation interval (ns) */ + u64 last_dispatch; + + /* beginning of the last budget */ + ktime_t last_budget_start; + /* beginning of the last idle slice */ + ktime_t last_idling_start; + + /* number of samples in current observation interval */ + int peak_rate_samples; + /* num of samples of seq dispatches in current observation interval */ + u32 sequential_samples; + /* total num of sectors transferred in current observation interval */ + u64 tot_sectors_dispatched; + /* max rq size seen during current observation interval (sectors) */ + u32 last_rq_max_size; + /* time elapsed from first dispatch in current observ. interval (us) */ + u64 delta_from_first; + /* current estimate of device peak rate */ + u32 peak_rate; + + /* maximum budget allotted to a bfq_queue before rescheduling */ + int bfq_max_budget; + + /* list of all the bfq_queues active on the device */ + struct list_head active_list; + /* list of all the bfq_queues idle on the device */ + struct list_head idle_list; + + /* + * Timeout for async/sync requests; when it fires, requests + * are served in fifo order. + */ + u64 bfq_fifo_expire[2]; + /* weight of backward seeks wrt forward ones */ + unsigned int bfq_back_penalty; + /* maximum allowed backward seek */ + unsigned int bfq_back_max; + /* maximum idling time */ + u32 bfq_slice_idle; + + /* user-configured max budget value (0 for auto-tuning) */ + int bfq_user_max_budget; + /* + * Timeout for bfq_queues to consume their budget; used to + * prevent seeky queues from imposing long latencies to + * sequential or quasi-sequential ones (this also implies that + * seeky queues cannot receive guarantees in the service + * domain; after a timeout they are charged for the time they + * have been in service, to preserve fairness among them, but + * without service-domain guarantees). + */ + unsigned int bfq_timeout; + + /* + * Number of consecutive requests that must be issued within + * the idle time slice to set again idling to a queue which + * was marked as non-I/O-bound (see the definition of the + * IO_bound flag for further details). + */ + unsigned int bfq_requests_within_timer; + + /* + * Force device idling whenever needed to provide accurate + * service guarantees, without caring about throughput + * issues. CAVEAT: this may even increase latencies, in case + * of useless idling for processes that did stop doing I/O. + */ + bool strict_guarantees; + + /* + * Last time at which a queue entered the current burst of + * queues being activated shortly after each other; for more + * details about this and the following parameters related to + * a burst of activations, see the comments on the function + * bfq_handle_burst. + */ + unsigned long last_ins_in_burst; + /* + * Reference time interval used to decide whether a queue has + * been activated shortly after @last_ins_in_burst. + */ + unsigned long bfq_burst_interval; + /* number of queues in the current burst of queue activations */ + int burst_size; + + /* common parent entity for the queues in the burst */ + struct bfq_entity *burst_parent_entity; + /* Maximum burst size above which the current queue-activation + * burst is deemed as 'large'. + */ + unsigned long bfq_large_burst_thresh; + /* true if a large queue-activation burst is in progress */ + bool large_burst; + /* + * Head of the burst list (as for the above fields, more + * details in the comments on the function bfq_handle_burst). + */ + struct hlist_head burst_list; + + /* if set to true, low-latency heuristics are enabled */ + bool low_latency; + /* + * Maximum factor by which the weight of a weight-raised queue + * is multiplied. + */ + unsigned int bfq_wr_coeff; + /* maximum duration of a weight-raising period (jiffies) */ + unsigned int bfq_wr_max_time; + + /* Maximum weight-raising duration for soft real-time processes */ + unsigned int bfq_wr_rt_max_time; + /* + * Minimum idle period after which weight-raising may be + * reactivated for a queue (in jiffies). + */ + unsigned int bfq_wr_min_idle_time; + /* + * Minimum period between request arrivals after which + * weight-raising may be reactivated for an already busy async + * queue (in jiffies). + */ + unsigned long bfq_wr_min_inter_arr_async; + + /* Max service-rate for a soft real-time queue, in sectors/sec */ + unsigned int bfq_wr_max_softrt_rate; + /* + * Cached value of the product R*T, used for computing the + * maximum duration of weight raising automatically. + */ + u64 RT_prod; + /* device-speed class for the low-latency heuristic */ + enum bfq_device_speed device_speed; + + /* fallback dummy bfqq for extreme OOM conditions */ + struct bfq_queue oom_bfqq; + + spinlock_t lock; + + /* + * bic associated with the task issuing current bio for + * merging. This and the next field are used as a support to + * be able to perform the bic lookup, needed by bio-merge + * functions, before the scheduler lock is taken, and thus + * avoid taking the request-queue lock while the scheduler + * lock is being held. + */ + struct bfq_io_cq *bio_bic; + /* bfqq associated with the task issuing current bio for merging */ + struct bfq_queue *bio_bfqq; + /* Extra flag used only for TESTING */ + bool bio_bfqq_set; +}; + +enum bfqq_state_flags { + BFQ_BFQQ_FLAG_just_created = 0, /* queue just allocated */ + BFQ_BFQQ_FLAG_busy, /* has requests or is in service */ + BFQ_BFQQ_FLAG_wait_request, /* waiting for a request */ + BFQ_BFQQ_FLAG_non_blocking_wait_rq, /* + * waiting for a request + * without idling the device + */ + BFQ_BFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ + BFQ_BFQQ_FLAG_has_short_ttime, /* queue has a short think time */ + BFQ_BFQQ_FLAG_sync, /* synchronous queue */ + BFQ_BFQQ_FLAG_IO_bound, /* + * bfqq has timed-out at least once + * having consumed at most 2/10 of + * its budget + */ + BFQ_BFQQ_FLAG_in_large_burst, /* + * bfqq activated in a large burst, + * see comments to bfq_handle_burst. + */ + BFQ_BFQQ_FLAG_softrt_update, /* + * may need softrt-next-start + * update + */ + BFQ_BFQQ_FLAG_coop, /* bfqq is shared */ + BFQ_BFQQ_FLAG_split_coop /* shared bfqq will be split */ +}; + +#define BFQ_BFQQ_FNS(name) \ +static void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ +{ \ + (bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \ +} \ +static void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ +{ \ + (bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \ +} \ +static int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ +{ \ + return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \ +} + +BFQ_BFQQ_FNS(just_created); +BFQ_BFQQ_FNS(busy); +BFQ_BFQQ_FNS(wait_request); +BFQ_BFQQ_FNS(non_blocking_wait_rq); +BFQ_BFQQ_FNS(fifo_expire); +BFQ_BFQQ_FNS(has_short_ttime); +BFQ_BFQQ_FNS(sync); +BFQ_BFQQ_FNS(IO_bound); +BFQ_BFQQ_FNS(in_large_burst); +BFQ_BFQQ_FNS(coop); +BFQ_BFQQ_FNS(split_coop); +BFQ_BFQQ_FNS(softrt_update); +#undef BFQ_BFQQ_FNS + +/* Logging facilities. */ +#ifdef CONFIG_BFQ_REDIRECT_TO_CONSOLE + +static const char *checked_dev_name(const struct device *dev) +{ + static const char nodev[] = "nodev"; + + if (dev) + return dev_name(dev); + + return nodev; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ + pr_crit("%s bfq%d%c %s " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + bfqq_group(bfqq)->blkg_path, ##args); \ +} while (0) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ + pr_crit("%s %s " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + bfqg->blkg_path, ##args); \ +} while (0) + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ + pr_crit("%s bfq%d%c " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + (bfqq)->pid, bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + ##args) +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) + +#endif /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log(bfqd, fmt, args...) \ + pr_crit("%s bfq " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + ##args) + +#else /* CONFIG_BFQ_REDIRECT_TO_CONSOLE */ + +#if !defined(CONFIG_BLK_DEV_IO_TRACE) + +/* Avoid possible "unused-variable" warning. See commit message. */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) ((void) (bfqq)) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) ((void) (bfqg)) + +#define bfq_log(bfqd, fmt, args...) do {} while (0) + +#else /* CONFIG_BLK_DEV_IO_TRACE */ + +#include + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ + blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, \ + (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + bfqq_group(bfqq)->blkg_path, ##args); \ +} while (0) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ + blk_add_trace_msg((bfqd)->queue, "%s " fmt, bfqg->blkg_path, ##args);\ +} while (0) + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ + blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + ##args) +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) + +#endif /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log(bfqd, fmt, args...) \ + blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) + +#endif /* CONFIG_BLK_DEV_IO_TRACE */ +#endif /* CONFIG_BFQ_REDIRECT_TO_CONSOLE */ + +/* Expiration reasons. */ +enum bfqq_expiration { + BFQ_BFQQ_TOO_IDLE = 0, /* + * queue has been idling for + * too long + */ + BFQ_BFQQ_BUDGET_TIMEOUT, /* budget took too long to be used */ + BFQ_BFQQ_BUDGET_EXHAUSTED, /* budget consumed */ + BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */ + BFQ_BFQQ_PREEMPTED /* preemption in progress */ +}; + + +struct bfqg_stats { +#ifdef BFQ_GROUP_IOSCHED_ENABLED + /* number of ios merged */ + struct blkg_rwstat merged; + /* total time spent on device in ns, may not be accurate w/ queueing */ + struct blkg_rwstat service_time; + /* total time spent waiting in scheduler queue in ns */ + struct blkg_rwstat wait_time; + /* number of IOs queued up */ + struct blkg_rwstat queued; + /* total disk time and nr sectors dispatched by this group */ + struct blkg_stat time; + /* sum of number of ios queued across all samples */ + struct blkg_stat avg_queue_size_sum; + /* count of samples taken for average */ + struct blkg_stat avg_queue_size_samples; + /* how many times this group has been removed from service tree */ + struct blkg_stat dequeue; + /* total time spent waiting for it to be assigned a timeslice. */ + struct blkg_stat group_wait_time; + /* time spent idling for this blkcg_gq */ + struct blkg_stat idle_time; + /* total time with empty current active q with other requests queued */ + struct blkg_stat empty_time; + /* fields after this shouldn't be cleared on stat reset */ + uint64_t start_group_wait_time; + uint64_t start_idle_time; + uint64_t start_empty_time; + uint16_t flags; +#endif +}; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +/* + * struct bfq_group_data - per-blkcg storage for the blkio subsystem. + * + * @ps: @blkcg_policy_storage that this structure inherits + * @weight: weight of the bfq_group + */ +struct bfq_group_data { + /* must be the first member */ + struct blkcg_policy_data pd; + + unsigned int weight; +}; + +/** + * struct bfq_group - per (device, cgroup) data structure. + * @entity: schedulable entity to insert into the parent group sched_data. + * @sched_data: own sched_data, to contain child entities (they may be + * both bfq_queues and bfq_groups). + * @bfqd: the bfq_data for the device this group acts upon. + * @async_bfqq: array of async queues for all the tasks belonging to + * the group, one queue per ioprio value per ioprio_class, + * except for the idle class that has only one queue. + * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). + * @my_entity: pointer to @entity, %NULL for the toplevel group; used + * to avoid too many special cases during group creation/ + * migration. + * @active_entities: number of active entities belonging to the group; + * unused for the root group. Used to know whether there + * are groups with more than one active @bfq_entity + * (see the comments to the function + * bfq_bfqq_may_idle()). + * @rq_pos_tree: rbtree sorted by next_request position, used when + * determining if two or more queues have interleaving + * requests (see bfq_find_close_cooperator()). + * + * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup + * there is a set of bfq_groups, each one collecting the lower-level + * entities belonging to the group that are acting on the same device. + * + * Locking works as follows: + * o @bfqd is protected by the queue lock, RCU is used to access it + * from the readers. + * o All the other fields are protected by the @bfqd queue lock. + */ +struct bfq_group { + /* must be the first member */ + struct blkg_policy_data pd; + + /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */ + char blkg_path[128]; + + /* reference counter (see comments in bfq_bic_update_cgroup) */ + int ref; + + struct bfq_entity entity; + struct bfq_sched_data sched_data; + + void *bfqd; + + struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; + struct bfq_queue *async_idle_bfqq; + + struct bfq_entity *my_entity; + + int active_entities; + + struct rb_root rq_pos_tree; + + struct bfqg_stats stats; +}; + +#else +struct bfq_group { + struct bfq_sched_data sched_data; + + struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; + struct bfq_queue *async_idle_bfqq; + + struct rb_root rq_pos_tree; +}; +#endif + +static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); + +static unsigned int bfq_class_idx(struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + return bfqq ? bfqq->ioprio_class - 1 : + BFQ_DEFAULT_GRP_CLASS - 1; +} + +static struct bfq_service_tree * +bfq_entity_service_tree(struct bfq_entity *entity) +{ + struct bfq_sched_data *sched_data = entity->sched_data; + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + unsigned int idx = bfq_class_idx(entity); + + BUG_ON(idx >= BFQ_IOPRIO_CLASSES); + BUG_ON(sched_data == NULL); + + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "entity_service_tree %p %d", + sched_data->service_tree + idx, idx); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "entity_service_tree %p %d", + sched_data->service_tree + idx, idx); + } +#endif + return sched_data->service_tree + idx; +} + +static struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync) +{ + return bic->bfqq[is_sync]; +} + +static void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, + bool is_sync) +{ + bic->bfqq[is_sync] = bfqq; +} + +static struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) +{ + return bic->icq.q->elevator->elevator_data; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + struct bfq_entity *group_entity = bfqq->entity.parent; + + if (!group_entity) + group_entity = &bfqq->bfqd->root_group->entity; + + return container_of(group_entity, struct bfq_group, entity); +} + +#else + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + return bfqq->bfqd->root_group; +} + +#endif + +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio); +static void bfq_put_queue(struct bfq_queue *bfqq); +static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, + struct bio *bio, bool is_sync, + struct bfq_io_cq *bic); +static void bfq_end_wr_async_queues(struct bfq_data *bfqd, + struct bfq_group *bfqg); +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); +#endif +static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); + +#endif /* _BFQ_H */ diff --git b/block/bfq-sched.c b/block/bfq-sched.c new file mode 100644 index 0000000..e4a2553 --- /dev/null +++ b/block/bfq-sched.c @@ -0,0 +1,2057 @@ +/* + * BFQ: Hierarchical B-WF2Q+ scheduler. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2016 Paolo Valente + */ + +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); + +/** + * bfq_gt - compare two timestamps. + * @a: first ts. + * @b: second ts. + * + * Return @a > @b, dealing with wrapping correctly. + */ +static int bfq_gt(u64 a, u64 b) +{ + return (s64)(a - b) > 0; +} + +static struct bfq_entity *bfq_root_active_entity(struct rb_root *tree) +{ + struct rb_node *node = tree->rb_node; + + return rb_entry(node, struct bfq_entity, rb_node); +} + +static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, + bool expiration); + +static bool bfq_update_parent_budget(struct bfq_entity *next_in_service); + +/** + * bfq_update_next_in_service - update sd->next_in_service + * @sd: sched_data for which to perform the update. + * @new_entity: if not NULL, pointer to the entity whose activation, + * requeueing or repositionig triggered the invocation of + * this function. + * @expiration: id true, this function is being invoked after the + * expiration of the in-service entity + * + * This function is called to update sd->next_in_service, which, in + * its turn, may change as a consequence of the insertion or + * extraction of an entity into/from one of the active trees of + * sd. These insertions/extractions occur as a consequence of + * activations/deactivations of entities, with some activations being + * 'true' activations, and other activations being requeueings (i.e., + * implementing the second, requeueing phase of the mechanism used to + * reposition an entity in its active tree; see comments on + * __bfq_activate_entity and __bfq_requeue_entity for details). In + * both the last two activation sub-cases, new_entity points to the + * just activated or requeued entity. + * + * Returns true if sd->next_in_service changes in such a way that + * entity->parent may become the next_in_service for its parent + * entity. + */ +static bool bfq_update_next_in_service(struct bfq_sched_data *sd, + struct bfq_entity *new_entity, + bool expiration) +{ + struct bfq_entity *next_in_service = sd->next_in_service; + struct bfq_queue *bfqq; + bool parent_sched_may_change = false; + bool change_without_lookup = false; + + /* + * If this update is triggered by the activation, requeueing + * or repositiong of an entity that does not coincide with + * sd->next_in_service, then a full lookup in the active tree + * can be avoided. In fact, it is enough to check whether the + * just-modified entity has the same priority as + * sd->next_in_service, is eligible and has a lower virtual + * finish time than sd->next_in_service. If this compound + * condition holds, then the new entity becomes the new + * next_in_service. Otherwise no change is needed. + */ + if (new_entity && new_entity != sd->next_in_service) { + /* + * Flag used to decide whether to replace + * sd->next_in_service with new_entity. Tentatively + * set to true, and left as true if + * sd->next_in_service is NULL. + */ + change_without_lookup = true; + + /* + * If there is already a next_in_service candidate + * entity, then compare timestamps to decide whether + * to replace sd->service_tree with new_entity. + */ + if (next_in_service) { + unsigned int new_entity_class_idx = + bfq_class_idx(new_entity); + struct bfq_service_tree *st = + sd->service_tree + new_entity_class_idx; + + change_without_lookup = + (new_entity_class_idx == + bfq_class_idx(next_in_service) + && + !bfq_gt(new_entity->start, st->vtime) + && + bfq_gt(next_in_service->finish, + new_entity->finish)); + } + + if (change_without_lookup) { + next_in_service = new_entity; + bfqq = bfq_entity_to_bfqq(next_in_service); + + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "update_next_in_service: chose without lookup"); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(next_in_service, + struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data*)bfqg->bfqd, bfqg, + "update_next_in_service: chose without lookup"); + } +#endif + } + } + + if (!change_without_lookup) /* lookup needed */ + next_in_service = bfq_lookup_next_entity(sd, expiration); + + if (next_in_service) + parent_sched_may_change = !sd->next_in_service || + bfq_update_parent_budget(next_in_service); + + sd->next_in_service = next_in_service; + + if (!next_in_service) + return parent_sched_may_change; + + bfqq = bfq_entity_to_bfqq(next_in_service); + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "update_next_in_service: chosen this queue"); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(next_in_service, + struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "update_next_in_service: chosen this entity"); + } +#endif + return parent_sched_may_change; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +/* both next loops stop at one of the child entities of the root group */ +#define for_each_entity(entity) \ + for (; entity ; entity = entity->parent) + +/* + * For each iteration, compute parent in advance, so as to be safe if + * entity is deallocated during the iteration. Such a deallocation may + * happen as a consequence of a bfq_put_queue that frees the bfq_queue + * containing entity. + */ +#define for_each_entity_safe(entity, parent) \ + for (; entity && ({ parent = entity->parent; 1; }); entity = parent) + +/* + * Returns true if this budget changes may let next_in_service->parent + * become the next_in_service entity for its parent entity. + */ +static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) +{ + struct bfq_entity *bfqg_entity; + struct bfq_group *bfqg; + struct bfq_sched_data *group_sd; + bool ret = false; + + BUG_ON(!next_in_service); + + group_sd = next_in_service->sched_data; + + bfqg = container_of(group_sd, struct bfq_group, sched_data); + /* + * bfq_group's my_entity field is not NULL only if the group + * is not the root group. We must not touch the root entity + * as it must never become an in-service entity. + */ + bfqg_entity = bfqg->my_entity; + if (bfqg_entity) { + if (bfqg_entity->budget > next_in_service->budget) + ret = true; + bfqg_entity->budget = next_in_service->budget; + } + + return ret; +} + +/* + * This function tells whether entity stops being a candidate for next + * service, according to the restrictive definition of the field + * next_in_service. In particular, this function is invoked for an + * entity that is about to be set in service. + * + * If entity is a queue, then the entity is no longer a candidate for + * next service according to the that definition, because entity is + * about to become the in-service queue. This function then returns + * true if entity is a queue. + * + * In contrast, entity could still be a candidate for next service if + * it is not a queue, and has more than one active child. In fact, + * even if one of its children is about to be set in service, other + * active children may still be the next to serve, for the parent + * entity, even according to the above definition. As a consequence, a + * non-queue entity is not a candidate for next-service only if it has + * only one active child. And only if this condition holds, then this + * function returns true for a non-queue entity. + */ +static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) +{ + struct bfq_group *bfqg; + + if (bfq_entity_to_bfqq(entity)) + return true; + + bfqg = container_of(entity, struct bfq_group, entity); + + BUG_ON(bfqg == ((struct bfq_data *)(bfqg->bfqd))->root_group); + BUG_ON(bfqg->active_entities == 0); + /* + * The field active_entities does not always contain the + * actual number of active children entities: it happens to + * not account for the in-service entity in case the latter is + * removed from its active tree (which may get done after + * invoking the function bfq_no_longer_next_in_service in + * bfq_get_next_queue). Fortunately, here, i.e., while + * bfq_no_longer_next_in_service is not yet completed in + * bfq_get_next_queue, bfq_active_extract has not yet been + * invoked, and thus active_entities still coincides with the + * actual number of active entities. + */ + if (bfqg->active_entities == 1) + return true; + + return false; +} + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ +#define for_each_entity(entity) \ + for (; entity ; entity = NULL) + +#define for_each_entity_safe(entity, parent) \ + for (parent = NULL; entity ; entity = parent) + +static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) +{ + return false; +} + +static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) +{ + return true; +} + +#endif /* BFQ_GROUP_IOSCHED_ENABLED */ + +/* + * Shift for timestamp calculations. This actually limits the maximum + * service allowed in one timestamp delta (small shift values increase it), + * the maximum total weight that can be used for the queues in the system + * (big shift values increase it), and the period of virtual time + * wraparounds. + */ +#define WFQ_SERVICE_SHIFT 22 + +static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = NULL; + + BUG_ON(!entity); + + if (!entity->my_sched_data) + bfqq = container_of(entity, struct bfq_queue, entity); + + return bfqq; +} + + +/** + * bfq_delta - map service into the virtual time domain. + * @service: amount of service. + * @weight: scale factor (weight of an entity or weight sum). + */ +static u64 bfq_delta(unsigned long service, unsigned long weight) +{ + u64 d = (u64)service << WFQ_SERVICE_SHIFT; + + do_div(d, weight); + return d; +} + +/** + * bfq_calc_finish - assign the finish time to an entity. + * @entity: the entity to act upon. + * @service: the service to be charged to the entity. + */ +static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + unsigned long long start, finish, delta; + + BUG_ON(entity->weight == 0); + + entity->finish = entity->start + + bfq_delta(service, entity->weight); + + start = ((entity->start>>10)*1000)>>12; + finish = ((entity->finish>>10)*1000)>>12; + delta = ((bfq_delta(service, entity->weight)>>10)*1000)>>12; + + if (bfqq) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "calc_finish: serv %lu, w %d", + service, entity->weight); + bfq_log_bfqq(bfqq->bfqd, bfqq, + "calc_finish: start %llu, finish %llu, delta %llu", + start, finish, delta); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + } else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "calc_finish group: serv %lu, w %d", + service, entity->weight); + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "calc_finish group: start %llu, finish %llu, delta %llu", + start, finish, delta); +#endif + } +} + +/** + * bfq_entity_of - get an entity from a node. + * @node: the node field of the entity. + * + * Convert a node pointer to the relative entity. This is used only + * to simplify the logic of some functions and not as the generic + * conversion mechanism because, e.g., in the tree walking functions, + * the check for a %NULL value would be redundant. + */ +static struct bfq_entity *bfq_entity_of(struct rb_node *node) +{ + struct bfq_entity *entity = NULL; + + if (node) + entity = rb_entry(node, struct bfq_entity, rb_node); + + return entity; +} + +/** + * bfq_extract - remove an entity from a tree. + * @root: the tree root. + * @entity: the entity to remove. + */ +static void bfq_extract(struct rb_root *root, struct bfq_entity *entity) +{ + BUG_ON(entity->tree != root); + + entity->tree = NULL; + rb_erase(&entity->rb_node, root); +} + +/** + * bfq_idle_extract - extract an entity from the idle tree. + * @st: the service tree of the owning @entity. + * @entity: the entity being removed. + */ +static void bfq_idle_extract(struct bfq_service_tree *st, + struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + struct rb_node *next; + + BUG_ON(entity->tree != &st->idle); + + if (entity == st->first_idle) { + next = rb_next(&entity->rb_node); + st->first_idle = bfq_entity_of(next); + } + + if (entity == st->last_idle) { + next = rb_prev(&entity->rb_node); + st->last_idle = bfq_entity_of(next); + } + + bfq_extract(&st->idle, entity); + + if (bfqq) + list_del(&bfqq->bfqq_list); +} + +/** + * bfq_insert - generic tree insertion. + * @root: tree root. + * @entity: entity to insert. + * + * This is used for the idle and the active tree, since they are both + * ordered by finish time. + */ +static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) +{ + struct bfq_entity *entry; + struct rb_node **node = &root->rb_node; + struct rb_node *parent = NULL; + + BUG_ON(entity->tree); + + while (*node) { + parent = *node; + entry = rb_entry(parent, struct bfq_entity, rb_node); + + if (bfq_gt(entry->finish, entity->finish)) + node = &parent->rb_left; + else + node = &parent->rb_right; + } + + rb_link_node(&entity->rb_node, parent, node); + rb_insert_color(&entity->rb_node, root); + + entity->tree = root; +} + +/** + * bfq_update_min - update the min_start field of a entity. + * @entity: the entity to update. + * @node: one of its children. + * + * This function is called when @entity may store an invalid value for + * min_start due to updates to the active tree. The function assumes + * that the subtree rooted at @node (which may be its left or its right + * child) has a valid min_start value. + */ +static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node) +{ + struct bfq_entity *child; + + if (node) { + child = rb_entry(node, struct bfq_entity, rb_node); + if (bfq_gt(entity->min_start, child->min_start)) + entity->min_start = child->min_start; + } +} + +/** + * bfq_update_active_node - recalculate min_start. + * @node: the node to update. + * + * @node may have changed position or one of its children may have moved, + * this function updates its min_start value. The left and right subtrees + * are assumed to hold a correct min_start value. + */ +static void bfq_update_active_node(struct rb_node *node) +{ + struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + entity->min_start = entity->start; + bfq_update_min(entity, node->rb_right); + bfq_update_min(entity, node->rb_left); + + if (bfqq) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "update_active_node: new min_start %llu", + ((entity->min_start>>10)*1000)>>12); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + } else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "update_active_node: new min_start %llu", + ((entity->min_start>>10)*1000)>>12); +#endif + } +} + +/** + * bfq_update_active_tree - update min_start for the whole active tree. + * @node: the starting node. + * + * @node must be the deepest modified node after an update. This function + * updates its min_start using the values held by its children, assuming + * that they did not change, and then updates all the nodes that may have + * changed in the path to the root. The only nodes that may have changed + * are the ones in the path or their siblings. + */ +static void bfq_update_active_tree(struct rb_node *node) +{ + struct rb_node *parent; + +up: + bfq_update_active_node(node); + + parent = rb_parent(node); + if (!parent) + return; + + if (node == parent->rb_left && parent->rb_right) + bfq_update_active_node(parent->rb_right); + else if (parent->rb_left) + bfq_update_active_node(parent->rb_left); + + node = parent; + goto up; +} + +static void bfq_weights_tree_add(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root); + +static void bfq_weights_tree_remove(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root); + + +/** + * bfq_active_insert - insert an entity in the active tree of its + * group/device. + * @st: the service tree of the entity. + * @entity: the entity being inserted. + * + * The active tree is ordered by finish time, but an extra key is kept + * per each node, containing the minimum value for the start times of + * its children (and the node itself), so it's possible to search for + * the eligible node with the lowest finish time in logarithmic time. + */ +static void bfq_active_insert(struct bfq_service_tree *st, + struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + struct rb_node *node = &entity->rb_node; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + struct bfq_sched_data *sd = NULL; + struct bfq_group *bfqg = NULL; + struct bfq_data *bfqd = NULL; +#endif + + bfq_insert(&st->active, entity); + + if (node->rb_left) + node = node->rb_left; + else if (node->rb_right) + node = node->rb_right; + + bfq_update_active_tree(node); + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + sd = entity->sched_data; + bfqg = container_of(sd, struct bfq_group, sched_data); + BUG_ON(!bfqg); + bfqd = (struct bfq_data *)bfqg->bfqd; +#endif + if (bfqq) + list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { /* bfq_group */ + BUG_ON(!bfqd); + bfq_weights_tree_add(bfqd, entity, &bfqd->group_weights_tree); + } + if (bfqg != bfqd->root_group) { + BUG_ON(!bfqg); + BUG_ON(!bfqd); + bfqg->active_entities++; + } +#endif +} + +/** + * bfq_ioprio_to_weight - calc a weight from an ioprio. + * @ioprio: the ioprio value to convert. + */ +static unsigned short bfq_ioprio_to_weight(int ioprio) +{ + BUG_ON(ioprio < 0 || ioprio >= IOPRIO_BE_NR); + return (IOPRIO_BE_NR - ioprio) * BFQ_WEIGHT_CONVERSION_COEFF; +} + +/** + * bfq_weight_to_ioprio - calc an ioprio from a weight. + * @weight: the weight value to convert. + * + * To preserve as much as possible the old only-ioprio user interface, + * 0 is used as an escape ioprio value for weights (numerically) equal or + * larger than IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF. + */ +static unsigned short bfq_weight_to_ioprio(int weight) +{ + BUG_ON(weight < BFQ_MIN_WEIGHT || weight > BFQ_MAX_WEIGHT); + return IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight < 0 ? + 0 : IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight; +} + +static void bfq_get_entity(struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + if (bfqq) { + bfqq->ref++; + bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", + bfqq, bfqq->ref); + } +} + +/** + * bfq_find_deepest - find the deepest node that an extraction can modify. + * @node: the node being removed. + * + * Do the first step of an extraction in an rb tree, looking for the + * node that will replace @node, and returning the deepest node that + * the following modifications to the tree can touch. If @node is the + * last node in the tree return %NULL. + */ +static struct rb_node *bfq_find_deepest(struct rb_node *node) +{ + struct rb_node *deepest; + + if (!node->rb_right && !node->rb_left) + deepest = rb_parent(node); + else if (!node->rb_right) + deepest = node->rb_left; + else if (!node->rb_left) + deepest = node->rb_right; + else { + deepest = rb_next(node); + if (deepest->rb_right) + deepest = deepest->rb_right; + else if (rb_parent(deepest) != node) + deepest = rb_parent(deepest); + } + + return deepest; +} + +/** + * bfq_active_extract - remove an entity from the active tree. + * @st: the service_tree containing the tree. + * @entity: the entity being removed. + */ +static void bfq_active_extract(struct bfq_service_tree *st, + struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + struct rb_node *node; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + struct bfq_sched_data *sd = NULL; + struct bfq_group *bfqg = NULL; + struct bfq_data *bfqd = NULL; +#endif + + node = bfq_find_deepest(&entity->rb_node); + bfq_extract(&st->active, entity); + + if (node) + bfq_update_active_tree(node); + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + sd = entity->sched_data; + bfqg = container_of(sd, struct bfq_group, sched_data); + BUG_ON(!bfqg); + bfqd = (struct bfq_data *)bfqg->bfqd; +#endif + if (bfqq) + list_del(&bfqq->bfqq_list); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { /* bfq_group */ + BUG_ON(!bfqd); + bfq_weights_tree_remove(bfqd, entity, + &bfqd->group_weights_tree); + } + if (bfqg != bfqd->root_group) { + BUG_ON(!bfqg); + BUG_ON(!bfqd); + BUG_ON(!bfqg->active_entities); + bfqg->active_entities--; + } +#endif +} + +/** + * bfq_idle_insert - insert an entity into the idle tree. + * @st: the service tree containing the tree. + * @entity: the entity to insert. + */ +static void bfq_idle_insert(struct bfq_service_tree *st, + struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + struct bfq_entity *first_idle = st->first_idle; + struct bfq_entity *last_idle = st->last_idle; + + if (!first_idle || bfq_gt(first_idle->finish, entity->finish)) + st->first_idle = entity; + if (!last_idle || bfq_gt(entity->finish, last_idle->finish)) + st->last_idle = entity; + + bfq_insert(&st->idle, entity); + + if (bfqq) + list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); +} + +/** + * bfq_forget_entity - do not consider entity any longer for scheduling + * @st: the service tree. + * @entity: the entity being removed. + * @is_in_service: true if entity is currently the in-service entity. + * + * Forget everything about @entity. In addition, if entity represents + * a queue, and the latter is not in service, then release the service + * reference to the queue (the one taken through bfq_get_entity). In + * fact, in this case, there is really no more service reference to + * the queue, as the latter is also outside any service tree. If, + * instead, the queue is in service, then __bfq_bfqd_reset_in_service + * will take care of putting the reference when the queue finally + * stops being served. + */ +static void bfq_forget_entity(struct bfq_service_tree *st, + struct bfq_entity *entity, + bool is_in_service) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + BUG_ON(!entity->on_st); + + entity->on_st = false; + st->wsum -= entity->weight; + if (bfqq && !is_in_service) { + bfq_log_bfqq(bfqq->bfqd, bfqq, "forget_entity (before): %p %d", + bfqq, bfqq->ref); + bfq_put_queue(bfqq); + } +} + +/** + * bfq_put_idle_entity - release the idle tree ref of an entity. + * @st: service tree for the entity. + * @entity: the entity being released. + */ +static void bfq_put_idle_entity(struct bfq_service_tree *st, + struct bfq_entity *entity) +{ + bfq_idle_extract(st, entity); + bfq_forget_entity(st, entity, + entity == entity->sched_data->in_service_entity); +} + +/** + * bfq_forget_idle - update the idle tree if necessary. + * @st: the service tree to act upon. + * + * To preserve the global O(log N) complexity we only remove one entry here; + * as the idle tree will not grow indefinitely this can be done safely. + */ +static void bfq_forget_idle(struct bfq_service_tree *st) +{ + struct bfq_entity *first_idle = st->first_idle; + struct bfq_entity *last_idle = st->last_idle; + + if (RB_EMPTY_ROOT(&st->active) && last_idle && + !bfq_gt(last_idle->finish, st->vtime)) { + /* + * Forget the whole idle tree, increasing the vtime past + * the last finish time of idle entities. + */ + st->vtime = last_idle->finish; + } + + if (first_idle && !bfq_gt(first_idle->finish, st->vtime)) + bfq_put_idle_entity(st, first_idle); +} + +/* + * Update weight and priority of entity. If update_class_too is true, + * then update the ioprio_class of entity too. + * + * The reason why the update of ioprio_class is controlled through the + * last parameter is as follows. Changing the ioprio class of an + * entity implies changing the destination service trees for that + * entity. If such a change occurred when the entity is already on one + * of the service trees for its previous class, then the state of the + * entity would become more complex: none of the new possible service + * trees for the entity, according to bfq_entity_service_tree(), would + * match any of the possible service trees on which the entity + * is. Complex operations involving these trees, such as entity + * activations and deactivations, should take into account this + * additional complexity. To avoid this issue, this function is + * invoked with update_class_too unset in the points in the code where + * entity may happen to be on some tree. + */ +static struct bfq_service_tree * +__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, + struct bfq_entity *entity, + bool update_class_too) +{ + struct bfq_service_tree *new_st = old_st; + + if (entity->prio_changed) { + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + unsigned int prev_weight, new_weight; + struct bfq_data *bfqd = NULL; + struct rb_root *root; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + struct bfq_sched_data *sd; + struct bfq_group *bfqg; +#endif + + if (bfqq) + bfqd = bfqq->bfqd; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + sd = entity->my_sched_data; + bfqg = container_of(sd, struct bfq_group, sched_data); + BUG_ON(!bfqg); + bfqd = (struct bfq_data *)bfqg->bfqd; + BUG_ON(!bfqd); + } +#endif + + BUG_ON(entity->tree && update_class_too); + BUG_ON(old_st->wsum < entity->weight); + old_st->wsum -= entity->weight; + + if (entity->new_weight != entity->orig_weight) { + if (entity->new_weight < BFQ_MIN_WEIGHT || + entity->new_weight > BFQ_MAX_WEIGHT) { + pr_crit("update_weight_prio: new_weight %d\n", + entity->new_weight); + if (entity->new_weight < BFQ_MIN_WEIGHT) + entity->new_weight = BFQ_MIN_WEIGHT; + else + entity->new_weight = BFQ_MAX_WEIGHT; + } + entity->orig_weight = entity->new_weight; + if (bfqq) + bfqq->ioprio = + bfq_weight_to_ioprio(entity->orig_weight); + } + + if (bfqq && update_class_too) + bfqq->ioprio_class = bfqq->new_ioprio_class; + + /* + * Reset prio_changed only if the ioprio_class change + * is not pending any longer. + */ + if (!bfqq || bfqq->ioprio_class == bfqq->new_ioprio_class) + entity->prio_changed = 0; + + /* + * NOTE: here we may be changing the weight too early, + * this will cause unfairness. The correct approach + * would have required additional complexity to defer + * weight changes to the proper time instants (i.e., + * when entity->finish <= old_st->vtime). + */ + new_st = bfq_entity_service_tree(entity); + + prev_weight = entity->weight; + new_weight = entity->orig_weight * + (bfqq ? bfqq->wr_coeff : 1); + /* + * If the weight of the entity changes, remove the entity + * from its old weight counter (if there is a counter + * associated with the entity), and add it to the counter + * associated with its new weight. + */ + if (prev_weight != new_weight) { + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "weight changed %d %d(%d %d)", + prev_weight, new_weight, + entity->orig_weight, + bfqq->wr_coeff); + + root = bfqq ? &bfqd->queue_weights_tree : + &bfqd->group_weights_tree; + bfq_weights_tree_remove(bfqd, entity, root); + } + entity->weight = new_weight; + /* + * Add the entity to its weights tree only if it is + * not associated with a weight-raised queue. + */ + if (prev_weight != new_weight && + (bfqq ? bfqq->wr_coeff == 1 : 1)) + /* If we get here, root has been initialized. */ + bfq_weights_tree_add(bfqd, entity, root); + + new_st->wsum += entity->weight; + + if (new_st != old_st) { + BUG_ON(!update_class_too); + entity->start = new_st->vtime; + } + } + + return new_st; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); +#endif + +/** + * bfq_bfqq_served - update the scheduler status after selection for + * service. + * @bfqq: the queue being served. + * @served: bytes to transfer. + * + * NOTE: this can be optimized, as the timestamps of upper level entities + * are synchronized every time a new bfqq is selected for service. By now, + * we keep it to better check consistency. + */ +static void bfq_bfqq_served(struct bfq_queue *bfqq, int served) +{ + struct bfq_entity *entity = &bfqq->entity; + struct bfq_service_tree *st; + + for_each_entity(entity) { + st = bfq_entity_service_tree(entity); + + entity->service += served; + + BUG_ON(st->wsum == 0); + + st->vtime += bfq_delta(served, st->wsum); + bfq_forget_idle(st); + } +#ifdef BFQ_GROUP_IOSCHED_ENABLED + bfqg_stats_set_start_empty_time(bfqq_group(bfqq)); +#endif + st = bfq_entity_service_tree(&bfqq->entity); + bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs, vtime %llu on %p", + served, ((st->vtime>>10)*1000)>>12, st); +} + +/** + * bfq_bfqq_charge_time - charge an amount of service equivalent to the length + * of the time interval during which bfqq has been in + * service. + * @bfqd: the device + * @bfqq: the queue that needs a service update. + * @time_ms: the amount of time during which the queue has received service + * + * If a queue does not consume its budget fast enough, then providing + * the queue with service fairness may impair throughput, more or less + * severely. For this reason, queues that consume their budget slowly + * are provided with time fairness instead of service fairness. This + * goal is achieved through the BFQ scheduling engine, even if such an + * engine works in the service, and not in the time domain. The trick + * is charging these queues with an inflated amount of service, equal + * to the amount of service that they would have received during their + * service slot if they had been fast, i.e., if their requests had + * been dispatched at a rate equal to the estimated peak rate. + * + * It is worth noting that time fairness can cause important + * distortions in terms of bandwidth distribution, on devices with + * internal queueing. The reason is that I/O requests dispatched + * during the service slot of a queue may be served after that service + * slot is finished, and may have a total processing time loosely + * correlated with the duration of the service slot. This is + * especially true for short service slots. + */ +static void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, + unsigned long time_ms) +{ + struct bfq_entity *entity = &bfqq->entity; + int tot_serv_to_charge = entity->service; + unsigned int timeout_ms = jiffies_to_msecs(bfq_timeout); + + if (time_ms > 0 && time_ms < timeout_ms) + tot_serv_to_charge = + (bfqd->bfq_max_budget * time_ms) / timeout_ms; + + if (tot_serv_to_charge < entity->service) + tot_serv_to_charge = entity->service; + + bfq_log_bfqq(bfqq->bfqd, bfqq, + "charge_time: %lu/%u ms, %d/%d/%d sectors", + time_ms, timeout_ms, entity->service, + tot_serv_to_charge, entity->budget); + + /* Increase budget to avoid inconsistencies */ + if (tot_serv_to_charge > entity->budget) + entity->budget = tot_serv_to_charge; + + bfq_bfqq_served(bfqq, + max_t(int, 0, tot_serv_to_charge - entity->service)); +} + +static void bfq_update_fin_time_enqueue(struct bfq_entity *entity, + struct bfq_service_tree *st, + bool backshifted) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + struct bfq_sched_data *sd = entity->sched_data; + + /* + * When this function is invoked, entity is not in any service + * tree, then it is safe to invoke next function with the last + * parameter set (see the comments on the function). + */ + BUG_ON(entity->tree); + st = __bfq_entity_update_weight_prio(st, entity, true); + bfq_calc_finish(entity, entity->budget); + + /* + * If some queues enjoy backshifting for a while, then their + * (virtual) finish timestamps may happen to become lower and + * lower than the system virtual time. In particular, if + * these queues often happen to be idle for short time + * periods, and during such time periods other queues with + * higher timestamps happen to be busy, then the backshifted + * timestamps of the former queues can become much lower than + * the system virtual time. In fact, to serve the queues with + * higher timestamps while the ones with lower timestamps are + * idle, the system virtual time may be pushed-up to much + * higher values than the finish timestamps of the idle + * queues. As a consequence, the finish timestamps of all new + * or newly activated queues may end up being much larger than + * those of lucky queues with backshifted timestamps. The + * latter queues may then monopolize the device for a lot of + * time. This would simply break service guarantees. + * + * To reduce this problem, push up a little bit the + * backshifted timestamps of the queue associated with this + * entity (only a queue can happen to have the backshifted + * flag set): just enough to let the finish timestamp of the + * queue be equal to the current value of the system virtual + * time. This may introduce a little unfairness among queues + * with backshifted timestamps, but it does not break + * worst-case fairness guarantees. + * + * As a special case, if bfqq is weight-raised, push up + * timestamps much less, to keep very low the probability that + * this push up causes the backshifted finish timestamps of + * weight-raised queues to become higher than the backshifted + * finish timestamps of non weight-raised queues. + */ + if (backshifted && bfq_gt(st->vtime, entity->finish)) { + unsigned long delta = st->vtime - entity->finish; + + if (bfqq) + delta /= bfqq->wr_coeff; + + entity->start += delta; + entity->finish += delta; + + if (bfqq) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "update_fin_time_enqueue: new queue finish %llu", + ((entity->finish>>10)*1000)>>12); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + } else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "update_fin_time_enqueue: new group finish %llu", + ((entity->finish>>10)*1000)>>12); +#endif + } + } + + bfq_active_insert(st, entity); + + if (bfqq) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "update_fin_time_enqueue: queue %seligible in st %p", + entity->start <= st->vtime ? "" : "non ", st); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + } else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "update_fin_time_enqueue: group %seligible in st %p", + entity->start <= st->vtime ? "" : "non ", st); +#endif + } + BUG_ON(RB_EMPTY_ROOT(&st->active)); + BUG_ON(&st->active != &sd->service_tree->active && + &st->active != &(sd->service_tree+1)->active && + &st->active != &(sd->service_tree+2)->active); +} + +/** + * __bfq_activate_entity - handle activation of entity. + * @entity: the entity being activated. + * @non_blocking_wait_rq: true if entity was waiting for a request + * + * Called for a 'true' activation, i.e., if entity is not active and + * one of its children receives a new request. + * + * Basically, this function updates the timestamps of entity and + * inserts entity into its active tree, ater possibly extracting it + * from its idle tree. + */ +static void __bfq_activate_entity(struct bfq_entity *entity, + bool non_blocking_wait_rq) +{ + struct bfq_sched_data *sd = entity->sched_data; + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + bool backshifted = false; + unsigned long long min_vstart; + + BUG_ON(!sd); + BUG_ON(!st); + + /* See comments on bfq_fqq_update_budg_for_activation */ + if (non_blocking_wait_rq && bfq_gt(st->vtime, entity->finish)) { + backshifted = true; + min_vstart = entity->finish; + } else + min_vstart = st->vtime; + + if (entity->tree == &st->idle) { + /* + * Must be on the idle tree, bfq_idle_extract() will + * check for that. + */ + bfq_idle_extract(st, entity); + BUG_ON(entity->tree); + entity->start = bfq_gt(min_vstart, entity->finish) ? + min_vstart : entity->finish; + } else { + BUG_ON(entity->tree); + /* + * The finish time of the entity may be invalid, and + * it is in the past for sure, otherwise the queue + * would have been on the idle tree. + */ + entity->start = min_vstart; + st->wsum += entity->weight; + /* + * entity is about to be inserted into a service tree, + * and then set in service: get a reference to make + * sure entity does not disappear until it is no + * longer in service or scheduled for service. + */ + bfq_get_entity(entity); + + BUG_ON(entity->on_st && bfqq); + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + if (entity->on_st && !bfqq) { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, + entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, + bfqg, + "activate bug, class %d in_service %p", + bfq_class_idx(entity), sd->in_service_entity); + } +#endif + BUG_ON(entity->on_st && !bfqq); + entity->on_st = true; + } + + bfq_update_fin_time_enqueue(entity, st, backshifted); +} + +/** + * __bfq_requeue_entity - handle requeueing or repositioning of an entity. + * @entity: the entity being requeued or repositioned. + * + * Requeueing is needed if this entity stops being served, which + * happens if a leaf descendant entity has expired. On the other hand, + * repositioning is needed if the next_inservice_entity for the child + * entity has changed. See the comments inside the function for + * details. + * + * Basically, this function: 1) removes entity from its active tree if + * present there, 2) updates the timestamps of entity and 3) inserts + * entity back into its active tree (in the new, right position for + * the new values of the timestamps). + */ +static void __bfq_requeue_entity(struct bfq_entity *entity) +{ + struct bfq_sched_data *sd = entity->sched_data; + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + + BUG_ON(!sd); + BUG_ON(!st); + + BUG_ON(entity != sd->in_service_entity && + entity->tree != &st->active); + + if (entity == sd->in_service_entity) { + /* + * We are requeueing the current in-service entity, + * which may have to be done for one of the following + * reasons: + * - entity represents the in-service queue, and the + * in-service queue is being requeued after an + * expiration; + * - entity represents a group, and its budget has + * changed because one of its child entities has + * just been either activated or requeued for some + * reason; the timestamps of the entity need then to + * be updated, and the entity needs to be enqueued + * or repositioned accordingly. + * + * In particular, before requeueing, the start time of + * the entity must be moved forward to account for the + * service that the entity has received while in + * service. This is done by the next instructions. The + * finish time will then be updated according to this + * new value of the start time, and to the budget of + * the entity. + */ + bfq_calc_finish(entity, entity->service); + entity->start = entity->finish; + BUG_ON(entity->tree && entity->tree == &st->idle); + BUG_ON(entity->tree && entity->tree != &st->active); + /* + * In addition, if the entity had more than one child + * when set in service, then it was not extracted from + * the active tree. This implies that the position of + * the entity in the active tree may need to be + * changed now, because we have just updated the start + * time of the entity, and we will update its finish + * time in a moment (the requeueing is then, more + * precisely, a repositioning in this case). To + * implement this repositioning, we: 1) dequeue the + * entity here, 2) update the finish time and requeue + * the entity according to the new timestamps below. + */ + if (entity->tree) + bfq_active_extract(st, entity); + } else { /* The entity is already active, and not in service */ + /* + * In this case, this function gets called only if the + * next_in_service entity below this entity has + * changed, and this change has caused the budget of + * this entity to change, which, finally implies that + * the finish time of this entity must be + * updated. Such an update may cause the scheduling, + * i.e., the position in the active tree, of this + * entity to change. We handle this change by: 1) + * dequeueing the entity here, 2) updating the finish + * time and requeueing the entity according to the new + * timestamps below. This is the same approach as the + * non-extracted-entity sub-case above. + */ + bfq_active_extract(st, entity); + } + + bfq_update_fin_time_enqueue(entity, st, false); +} + +static void __bfq_activate_requeue_entity(struct bfq_entity *entity, + struct bfq_sched_data *sd, + bool non_blocking_wait_rq) +{ + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + + if (sd->in_service_entity == entity || entity->tree == &st->active) + /* + * in service or already queued on the active tree, + * requeue or reposition + */ + __bfq_requeue_entity(entity); + else + /* + * Not in service and not queued on its active tree: + * the activity is idle and this is a true activation. + */ + __bfq_activate_entity(entity, non_blocking_wait_rq); +} + + +/** + * bfq_activate_requeue_entity - activate or requeue an entity representing a bfq_queue, + * and activate, requeue or reposition all ancestors + * for which such an update becomes necessary. + * @entity: the entity to activate. + * @non_blocking_wait_rq: true if this entity was waiting for a request + * @requeue: true if this is a requeue, which implies that bfqq is + * being expired; thus ALL its ancestors stop being served and must + * therefore be requeued + * @expiration: true if this function is being invoked in the expiration path + * of the in-service queue + */ +static void bfq_activate_requeue_entity(struct bfq_entity *entity, + bool non_blocking_wait_rq, + bool requeue, bool expiration) +{ + struct bfq_sched_data *sd; + + for_each_entity(entity) { + BUG_ON(!entity); + sd = entity->sched_data; + __bfq_activate_requeue_entity(entity, sd, non_blocking_wait_rq); + + BUG_ON(RB_EMPTY_ROOT(&sd->service_tree->active) && + RB_EMPTY_ROOT(&(sd->service_tree+1)->active) && + RB_EMPTY_ROOT(&(sd->service_tree+2)->active)); + + if (!bfq_update_next_in_service(sd, entity, expiration) && + !requeue) { + BUG_ON(!sd->next_in_service); + break; + } + BUG_ON(!sd->next_in_service); + } +} + +/** + * __bfq_deactivate_entity - deactivate an entity from its service tree. + * @entity: the entity to deactivate. + * @ins_into_idle_tree: if false, the entity will not be put into the + * idle tree. + * + * Deactivates an entity, independently of its previous state. Must + * be invoked only if entity is on a service tree. Extracts the entity + * from that tree, and if necessary and allowed, puts it into the idle + * tree. + */ +static bool __bfq_deactivate_entity(struct bfq_entity *entity, + bool ins_into_idle_tree) +{ + struct bfq_sched_data *sd = entity->sched_data; + struct bfq_service_tree *st; + bool is_in_service; + + if (!entity->on_st) { /* entity never activated, or already inactive */ + BUG_ON(sd && entity == sd->in_service_entity); + return false; + } + + /* + * If we get here, then entity is active, which implies that + * bfq_group_set_parent has already been invoked for the group + * represented by entity. Therefore, the field + * entity->sched_data has been set, and we can safely use it. + */ + st = bfq_entity_service_tree(entity); + is_in_service = entity == sd->in_service_entity; + + BUG_ON(is_in_service && entity->tree && entity->tree != &st->active); + + if (is_in_service) { + bfq_calc_finish(entity, entity->service); + sd->in_service_entity = NULL; + } + + if (entity->tree == &st->active) + bfq_active_extract(st, entity); + else if (!is_in_service && entity->tree == &st->idle) + bfq_idle_extract(st, entity); + else if (entity->tree) + BUG(); + + if (!ins_into_idle_tree || !bfq_gt(entity->finish, st->vtime)) + bfq_forget_entity(st, entity, is_in_service); + else + bfq_idle_insert(st, entity); + + return true; +} + +/** + * bfq_deactivate_entity - deactivate an entity representing a bfq_queue. + * @entity: the entity to deactivate. + * @ins_into_idle_tree: true if the entity can be put into the idle tree + * @expiration: true if this function is being invoked in the expiration path + * of the in-service queue + */ +static void bfq_deactivate_entity(struct bfq_entity *entity, + bool ins_into_idle_tree, + bool expiration) +{ + struct bfq_sched_data *sd; + struct bfq_entity *parent = NULL; + + for_each_entity_safe(entity, parent) { + sd = entity->sched_data; + + BUG_ON(sd == NULL); /* + * It would mean that this is the + * root group. + */ + + BUG_ON(expiration && entity != sd->in_service_entity); + + BUG_ON(entity != sd->in_service_entity && + entity->tree == + &bfq_entity_service_tree(entity)->active && + !sd->next_in_service); + + if (!__bfq_deactivate_entity(entity, ins_into_idle_tree)) { + /* + * entity is not in any tree any more, so + * this deactivation is a no-op, and there is + * nothing to change for upper-level entities + * (in case of expiration, this can never + * happen). + */ + BUG_ON(expiration); /* + * entity cannot be already out of + * any tree + */ + return; + } + + if (sd->next_in_service == entity) + /* + * entity was the next_in_service entity, + * then, since entity has just been + * deactivated, a new one must be found. + */ + bfq_update_next_in_service(sd, NULL, expiration); + + if (sd->next_in_service || sd->in_service_entity) { + /* + * The parent entity is still active, because + * either next_in_service or in_service_entity + * is not NULL. So, no further upwards + * deactivation must be performed. Yet, + * next_in_service has changed. Then the + * schedule does need to be updated upwards. + * + * NOTE If in_service_entity is not NULL, then + * next_in_service may happen to be NULL, + * although the parent entity is evidently + * active. This happens if 1) the entity + * pointed by in_service_entity is the only + * active entity in the parent entity, and 2) + * according to the definition of + * next_in_service, the in_service_entity + * cannot be considered as + * next_in_service. See the comments on the + * definition of next_in_service for details. + */ + BUG_ON(sd->next_in_service == entity); + BUG_ON(sd->in_service_entity == entity); + break; + } + + /* + * If we get here, then the parent is no more + * backlogged and we need to propagate the + * deactivation upwards. Thus let the loop go on. + */ + + /* + * Also let parent be queued into the idle tree on + * deactivation, to preserve service guarantees, and + * assuming that who invoked this function does not + * need parent entities too to be removed completely. + */ + ins_into_idle_tree = true; + } + + /* + * If the deactivation loop is fully executed, then there are + * no more entities to touch and next loop is not executed at + * all. Otherwise, requeue remaining entities if they are + * about to stop receiving service, or reposition them if this + * is not the case. + */ + entity = parent; + for_each_entity(entity) { + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + /* + * Invoke __bfq_requeue_entity on entity, even if + * already active, to requeue/reposition it in the + * active tree (because sd->next_in_service has + * changed) + */ + __bfq_requeue_entity(entity); + + sd = entity->sched_data; + BUG_ON(expiration && sd->in_service_entity != entity); + + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "invoking udpdate_next for this queue"); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, + struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "invoking udpdate_next for this entity"); + } +#endif + if (!bfq_update_next_in_service(sd, entity, expiration) && + !expiration) + /* + * next_in_service unchanged or not causing + * any change in entity->parent->sd, and no + * requeueing needed for expiration: stop + * here. + */ + break; + } +} + +/** + * bfq_calc_vtime_jump - compute the value to which the vtime should jump, + * if needed, to have at least one entity eligible. + * @st: the service tree to act upon. + * + * Assumes that st is not empty. + */ +static u64 bfq_calc_vtime_jump(struct bfq_service_tree *st) +{ + struct bfq_entity *root_entity = bfq_root_active_entity(&st->active); + + if (bfq_gt(root_entity->min_start, st->vtime)) { + struct bfq_queue *bfqq = bfq_entity_to_bfqq(root_entity); + + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "calc_vtime_jump: new value %llu", + ((root_entity->min_start>>10)*1000)>>12); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(root_entity, struct bfq_group, + entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "calc_vtime_jump: new value %llu", + ((root_entity->min_start>>10)*1000)>>12); + } +#endif + return root_entity->min_start; + } + return st->vtime; +} + +static void bfq_update_vtime(struct bfq_service_tree *st, u64 new_value) +{ + if (new_value > st->vtime) { + st->vtime = new_value; + bfq_forget_idle(st); + } +} + +/** + * bfq_first_active_entity - find the eligible entity with + * the smallest finish time + * @st: the service tree to select from. + * @vtime: the system virtual to use as a reference for eligibility + * + * This function searches the first schedulable entity, starting from the + * root of the tree and going on the left every time on this side there is + * a subtree with at least one eligible (start >= vtime) entity. The path on + * the right is followed only if a) the left subtree contains no eligible + * entities and b) no eligible entity has been found yet. + */ +static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st, + u64 vtime) +{ + struct bfq_entity *entry, *first = NULL; + struct rb_node *node = st->active.rb_node; + + while (node) { + entry = rb_entry(node, struct bfq_entity, rb_node); +left: + if (!bfq_gt(entry->start, vtime)) + first = entry; + + BUG_ON(bfq_gt(entry->min_start, vtime)); + + if (node->rb_left) { + entry = rb_entry(node->rb_left, + struct bfq_entity, rb_node); + if (!bfq_gt(entry->min_start, vtime)) { + node = node->rb_left; + goto left; + } + } + if (first) + break; + node = node->rb_right; + } + + BUG_ON(!first && !RB_EMPTY_ROOT(&st->active)); + return first; +} + +/** + * __bfq_lookup_next_entity - return the first eligible entity in @st. + * @st: the service tree. + * + * If there is no in-service entity for the sched_data st belongs to, + * then return the entity that will be set in service if: + * 1) the parent entity this st belongs to is set in service; + * 2) no entity belonging to such parent entity undergoes a state change + * that would influence the timestamps of the entity (e.g., becomes idle, + * becomes backlogged, changes its budget, ...). + * + * In this first case, update the virtual time in @st too (see the + * comments on this update inside the function). + * + * In constrast, if there is an in-service entity, then return the + * entity that would be set in service if not only the above + * conditions, but also the next one held true: the currently + * in-service entity, on expiration, + * 1) gets a finish time equal to the current one, or + * 2) is not eligible any more, or + * 3) is idle. + */ +static struct bfq_entity * +__bfq_lookup_next_entity(struct bfq_service_tree *st, bool in_service) +{ + struct bfq_entity *entity; + u64 new_vtime; + struct bfq_queue *bfqq; + + if (RB_EMPTY_ROOT(&st->active)) + return NULL; + + /* + * Get the value of the system virtual time for which at + * least one entity is eligible. + */ + new_vtime = bfq_calc_vtime_jump(st); + + /* + * If there is no in-service entity for the sched_data this + * active tree belongs to, then push the system virtual time + * up to the value that guarantees that at least one entity is + * eligible. If, instead, there is an in-service entity, then + * do not make any such update, because there is already an + * eligible entity, namely the in-service one (even if the + * entity is not on st, because it was extracted when set in + * service). + */ + if (!in_service) + bfq_update_vtime(st, new_vtime); + + entity = bfq_first_active_entity(st, new_vtime); + BUG_ON(bfq_gt(entity->start, new_vtime)); + + /* Log some information */ + bfqq = bfq_entity_to_bfqq(entity); + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "__lookup_next: start %llu vtime %llu st %p", + ((entity->start>>10)*1000)>>12, + ((new_vtime>>10)*1000)>>12, st); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "__lookup_next: start %llu vtime %llu (%llu) st %p", + ((entity->start>>10)*1000)>>12, + ((st->vtime>>10)*1000)>>12, + ((new_vtime>>10)*1000)>>12, st); + } +#endif + + BUG_ON(!entity); + + return entity; +} + +/** + * bfq_lookup_next_entity - return the first eligible entity in @sd. + * @sd: the sched_data. + * @expiration: true if we are on the expiration path of the in-service queue + * + * This function is invoked when there has been a change in the trees + * for sd, and we need to know what is the new next entity to serve + * after this change. + */ +static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, + bool expiration) +{ + struct bfq_service_tree *st = sd->service_tree; + struct bfq_service_tree *idle_class_st = st + (BFQ_IOPRIO_CLASSES - 1); + struct bfq_entity *entity = NULL; + struct bfq_queue *bfqq; + int class_idx = 0; + + BUG_ON(!sd); + BUG_ON(!st); + /* + * Choose from idle class, if needed to guarantee a minimum + * bandwidth to this class (and if there is some active entity + * in idle class). This should also mitigate + * priority-inversion problems in case a low priority task is + * holding file system resources. + */ + if (time_is_before_jiffies(sd->bfq_class_idle_last_service + + BFQ_CL_IDLE_TIMEOUT)) { + if (!RB_EMPTY_ROOT(&idle_class_st->active)) + class_idx = BFQ_IOPRIO_CLASSES - 1; + /* About to be served if backlogged, or not yet backlogged */ + sd->bfq_class_idle_last_service = jiffies; + } + + /* + * Find the next entity to serve for the highest-priority + * class, unless the idle class needs to be served. + */ + for (; class_idx < BFQ_IOPRIO_CLASSES; class_idx++) { + /* + * If expiration is true, then bfq_lookup_next_entity + * is being invoked as a part of the expiration path + * of the in-service queue. In this case, even if + * sd->in_service_entity is not NULL, + * sd->in_service_entiy at this point is actually not + * in service any more, and, if needed, has already + * been properly queued or requeued into the right + * tree. The reason why sd->in_service_entity is still + * not NULL here, even if expiration is true, is that + * sd->in_service_entiy is reset as a last step in the + * expiration path. So, if expiration is true, tell + * __bfq_lookup_next_entity that there is no + * sd->in_service_entity. + */ + entity = __bfq_lookup_next_entity(st + class_idx, + sd->in_service_entity && + !expiration); + + if (entity) + break; + } + + BUG_ON(!entity && + (!RB_EMPTY_ROOT(&st->active) || !RB_EMPTY_ROOT(&(st+1)->active) || + !RB_EMPTY_ROOT(&(st+2)->active))); + + if (!entity) + return NULL; + + /* Log some information */ + bfqq = bfq_entity_to_bfqq(entity); + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, "chosen from st %p %d", + st + class_idx, class_idx); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "chosen from st %p %d", + st + class_idx, class_idx); + } +#endif + + return entity; +} + +static bool next_queue_may_preempt(struct bfq_data *bfqd) +{ + struct bfq_sched_data *sd = &bfqd->root_group->sched_data; + + return sd->next_in_service != sd->in_service_entity; +} + +/* + * Get next queue for service. + */ +static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) +{ + struct bfq_entity *entity = NULL; + struct bfq_sched_data *sd; + struct bfq_queue *bfqq; + + BUG_ON(bfqd->in_service_queue); + + if (bfqd->busy_queues == 0) + return NULL; + + /* + * Traverse the path from the root to the leaf entity to + * serve. Set in service all the entities visited along the + * way. + */ + sd = &bfqd->root_group->sched_data; + for (; sd ; sd = entity->my_sched_data) { +#ifdef BFQ_GROUP_IOSCHED_ENABLED + if (entity) { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg(bfqd, bfqg, + "get_next_queue: lookup in this group"); + if (!sd->next_in_service) + pr_crit("get_next_queue: lookup in this group"); + } else { + bfq_log_bfqg(bfqd, bfqd->root_group, + "get_next_queue: lookup in root group"); + if (!sd->next_in_service) + pr_crit("get_next_queue: lookup in root group"); + } +#endif + + BUG_ON(!sd->next_in_service); + + /* + * WARNING. We are about to set the in-service entity + * to sd->next_in_service, i.e., to the (cached) value + * returned by bfq_lookup_next_entity(sd) the last + * time it was invoked, i.e., the last time when the + * service order in sd changed as a consequence of the + * activation or deactivation of an entity. In this + * respect, if we execute bfq_lookup_next_entity(sd) + * in this very moment, it may, although with low + * probability, yield a different entity than that + * pointed to by sd->next_in_service. This rare event + * happens in case there was no CLASS_IDLE entity to + * serve for sd when bfq_lookup_next_entity(sd) was + * invoked for the last time, while there is now one + * such entity. + * + * If the above event happens, then the scheduling of + * such entity in CLASS_IDLE is postponed until the + * service of the sd->next_in_service entity + * finishes. In fact, when the latter is expired, + * bfq_lookup_next_entity(sd) gets called again, + * exactly to update sd->next_in_service. + */ + + /* Make next_in_service entity become in_service_entity */ + entity = sd->next_in_service; + sd->in_service_entity = entity; + + /* + * Reset the accumulator of the amount of service that + * the entity is about to receive. + */ + entity->service = 0; + + /* + * If entity is no longer a candidate for next + * service, then it must be extracted from its active + * tree, so as to make sure that it won't be + * considered when computing next_in_service. See the + * comments on the function + * bfq_no_longer_next_in_service() for details. + */ + if (bfq_no_longer_next_in_service(entity)) + bfq_active_extract(bfq_entity_service_tree(entity), + entity); + + /* + * Even if entity is not to be extracted according to + * the above check, a descendant entity may get + * extracted in one of the next iterations of this + * loop. Such an event could cause a change in + * next_in_service for the level of the descendant + * entity, and thus possibly back to this level. + * + * However, we cannot perform the resulting needed + * update of next_in_service for this level before the + * end of the whole loop, because, to know which is + * the correct next-to-serve candidate entity for each + * level, we need first to find the leaf entity to set + * in service. In fact, only after we know which is + * the next-to-serve leaf entity, we can discover + * whether the parent entity of the leaf entity + * becomes the next-to-serve, and so on. + */ + + /* Log some information */ + bfqq = bfq_entity_to_bfqq(entity); + if (bfqq) + bfq_log_bfqq(bfqd, bfqq, + "get_next_queue: this queue, finish %llu", + (((entity->finish>>10)*1000)>>10)>>2); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg(bfqd, bfqg, + "get_next_queue: this entity, finish %llu", + (((entity->finish>>10)*1000)>>10)>>2); + } +#endif + + } + + BUG_ON(!entity); + bfqq = bfq_entity_to_bfqq(entity); + BUG_ON(!bfqq); + + /* + * We can finally update all next-to-serve entities along the + * path from the leaf entity just set in service to the root. + */ + for_each_entity(entity) { + struct bfq_sched_data *sd = entity->sched_data; + + if (!bfq_update_next_in_service(sd, NULL, false)) + break; + } + + return bfqq; +} + +static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd) +{ + struct bfq_queue *in_serv_bfqq = bfqd->in_service_queue; + struct bfq_entity *in_serv_entity = &in_serv_bfqq->entity; + struct bfq_entity *entity = in_serv_entity; + +#ifndef BFQ_MQ + if (bfqd->in_service_bic) { + put_io_context(bfqd->in_service_bic->icq.ioc); + bfqd->in_service_bic = NULL; + } +#endif + + bfq_clear_bfqq_wait_request(in_serv_bfqq); + hrtimer_try_to_cancel(&bfqd->idle_slice_timer); + bfqd->in_service_queue = NULL; + + /* + * When this function is called, all in-service entities have + * been properly deactivated or requeued, so we can safely + * execute the final step: reset in_service_entity along the + * path from entity to the root. + */ + for_each_entity(entity) + entity->sched_data->in_service_entity = NULL; + + /* + * in_serv_entity is no longer in service, so, if it is in no + * service tree either, then release the service reference to + * the queue it represents (taken with bfq_get_entity). + */ + if (!in_serv_entity->on_st) + bfq_put_queue(in_serv_bfqq); +} + +static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool ins_into_idle_tree, bool expiration) +{ + struct bfq_entity *entity = &bfqq->entity; + + bfq_deactivate_entity(entity, ins_into_idle_tree, expiration); +} + +static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + + BUG_ON(bfqq == bfqd->in_service_queue); + BUG_ON(entity->tree != &st->active && entity->tree != &st->idle && + entity->on_st); + + bfq_activate_requeue_entity(entity, bfq_bfqq_non_blocking_wait_rq(bfqq), + false, false); + bfq_clear_bfqq_non_blocking_wait_rq(bfqq); +} + +static void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool expiration) +{ + struct bfq_entity *entity = &bfqq->entity; + + bfq_activate_requeue_entity(entity, false, + bfqq == bfqd->in_service_queue, expiration); +} + +static void bfqg_stats_update_dequeue(struct bfq_group *bfqg); + +/* + * Called when the bfqq no longer has requests pending, remove it from + * the service tree. As a special case, it can be invoked during an + * expiration. + */ +static void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool expiration) +{ + BUG_ON(!bfq_bfqq_busy(bfqq)); + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); + + bfq_log_bfqq(bfqd, bfqq, "del from busy"); + + bfq_clear_bfqq_busy(bfqq); + + BUG_ON(bfqd->busy_queues == 0); + bfqd->busy_queues--; + + if (!bfqq->dispatched) + bfq_weights_tree_remove(bfqd, &bfqq->entity, + &bfqd->queue_weights_tree); + + if (bfqq->wr_coeff > 1) { + bfqd->wr_busy_queues--; + BUG_ON(bfqd->wr_busy_queues < 0); + } + + bfqg_stats_update_dequeue(bfqq_group(bfqq)); + + BUG_ON(bfqq->entity.budget < 0); + + bfq_deactivate_bfqq(bfqd, bfqq, true, expiration); +} + +/* + * Called when an inactive queue receives a new request. + */ +static void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + BUG_ON(bfq_bfqq_busy(bfqq)); + BUG_ON(bfqq == bfqd->in_service_queue); + + bfq_log_bfqq(bfqd, bfqq, "add to busy"); + + bfq_activate_bfqq(bfqd, bfqq); + + bfq_mark_bfqq_busy(bfqq); + bfqd->busy_queues++; + + if (!bfqq->dispatched) + if (bfqq->wr_coeff == 1) + bfq_weights_tree_add(bfqd, &bfqq->entity, + &bfqd->queue_weights_tree); + + if (bfqq->wr_coeff > 1) { + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + } + +} diff --git b/block/bfq-sq-iosched.c b/block/bfq-sq-iosched.c new file mode 100644 index 0000000..5b456e4 --- /dev/null +++ b/block/bfq-sq-iosched.c @@ -0,0 +1,5405 @@ +/* + * Budget Fair Queueing (BFQ) I/O scheduler. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2017 Paolo Valente + * + * Licensed under the GPL-2 as detailed in the accompanying COPYING.BFQ + * file. + * + * BFQ is a proportional-share I/O scheduler, with some extra + * low-latency capabilities. BFQ also supports full hierarchical + * scheduling through cgroups. Next paragraphs provide an introduction + * on BFQ inner workings. Details on BFQ benefits and usage can be + * found in Documentation/block/bfq-iosched.txt. + * + * BFQ is a proportional-share storage-I/O scheduling algorithm based + * on the slice-by-slice service scheme of CFQ. But BFQ assigns + * budgets, measured in number of sectors, to processes instead of + * time slices. The device is not granted to the in-service process + * for a given time slice, but until it has exhausted its assigned + * budget. This change from the time to the service domain enables BFQ + * to distribute the device throughput among processes as desired, + * without any distortion due to throughput fluctuations, or to device + * internal queueing. BFQ uses an ad hoc internal scheduler, called + * B-WF2Q+, to schedule processes according to their budgets. More + * precisely, BFQ schedules queues associated with processes. Thanks to + * the accurate policy of B-WF2Q+, BFQ can afford to assign high + * budgets to I/O-bound processes issuing sequential requests (to + * boost the throughput), and yet guarantee a low latency to + * interactive and soft real-time applications. + * + * NOTE: if the main or only goal, with a given device, is to achieve + * the maximum-possible throughput at all times, then do switch off + * all low-latency heuristics for that device, by setting low_latency + * to 0. + * + * BFQ is described in [1], where also a reference to the initial, more + * theoretical paper on BFQ can be found. The interested reader can find + * in the latter paper full details on the main algorithm, as well as + * formulas of the guarantees and formal proofs of all the properties. + * With respect to the version of BFQ presented in these papers, this + * implementation adds a few more heuristics, such as the one that + * guarantees a low latency to soft real-time applications, and a + * hierarchical extension based on H-WF2Q+. + * + * B-WF2Q+ is based on WF2Q+, that is described in [2], together with + * H-WF2Q+, while the augmented tree used to implement B-WF2Q+ with O(log N) + * complexity derives from the one introduced with EEVDF in [3]. + * + * [1] P. Valente, A. Avanzini, "Evolution of the BFQ Storage I/O + * Scheduler", Proceedings of the First Workshop on Mobile System + * Technologies (MST-2015), May 2015. + * http://algogroup.unimore.it/people/paolo/disk_sched/mst-2015.pdf + * + * http://algogroup.unimo.it/people/paolo/disk_sched/bf1-v1-suite-results.pdf + * + * [2] Jon C.R. Bennett and H. Zhang, ``Hierarchical Packet Fair Queueing + * Algorithms,'' IEEE/ACM Transactions on Networking, 5(5):675-689, + * Oct 1997. + * + * http://www.cs.cmu.edu/~hzhang/papers/TON-97-Oct.ps.gz + * + * [3] I. Stoica and H. Abdel-Wahab, ``Earliest Eligible Virtual Deadline + * First: A Flexible and Accurate Mechanism for Proportional Share + * Resource Allocation,'' technical report. + * + * http://www.cs.berkeley.edu/~istoica/papers/eevdf-tr-95.pdf + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include "blk.h" +#include "bfq.h" + +/* Expiration time of sync (0) and async (1) requests, in ns. */ +static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 }; + +/* Maximum backwards seek, in KiB. */ +static const int bfq_back_max = (16 * 1024); + +/* Penalty of a backwards seek, in number of sectors. */ +static const int bfq_back_penalty = 2; + +/* Idling period duration, in ns. */ +static u32 bfq_slice_idle = (NSEC_PER_SEC / 125); + +/* Minimum number of assigned budgets for which stats are safe to compute. */ +static const int bfq_stats_min_budgets = 194; + +/* Default maximum budget values, in sectors and number of requests. */ +static const int bfq_default_max_budget = (16 * 1024); + +/* + * Async to sync throughput distribution is controlled as follows: + * when an async request is served, the entity is charged the number + * of sectors of the request, multiplied by the factor below + */ +static const int bfq_async_charge_factor = 10; + +/* Default timeout values, in jiffies, approximating CFQ defaults. */ +static const int bfq_timeout = (HZ / 8); + +static struct kmem_cache *bfq_pool; + +/* Below this threshold (in ns), we consider thinktime immediate. */ +#define BFQ_MIN_TT (2 * NSEC_PER_MSEC) + +/* hw_tag detection: parallel requests threshold and min samples needed. */ +#define BFQ_HW_QUEUE_THRESHOLD 4 +#define BFQ_HW_QUEUE_SAMPLES 32 + +#define BFQQ_SEEK_THR (sector_t)(8 * 100) +#define BFQQ_SECT_THR_NONROT (sector_t)(2 * 32) +#define BFQQ_CLOSE_THR (sector_t)(8 * 1024) +#define BFQQ_SEEKY(bfqq) (hweight32(bfqq->seek_history) > 32/8) + +/* Min number of samples required to perform peak-rate update */ +#define BFQ_RATE_MIN_SAMPLES 32 +/* Min observation time interval required to perform a peak-rate update (ns) */ +#define BFQ_RATE_MIN_INTERVAL (300*NSEC_PER_MSEC) +/* Target observation time interval for a peak-rate update (ns) */ +#define BFQ_RATE_REF_INTERVAL NSEC_PER_SEC + +/* Shift used for peak rate fixed precision calculations. */ +#define BFQ_RATE_SHIFT 16 + +/* + * By default, BFQ computes the duration of the weight raising for + * interactive applications automatically, using the following formula: + * duration = (R / r) * T, where r is the peak rate of the device, and + * R and T are two reference parameters. + * In particular, R is the peak rate of the reference device (see below), + * and T is a reference time: given the systems that are likely to be + * installed on the reference device according to its speed class, T is + * about the maximum time needed, under BFQ and while reading two files in + * parallel, to load typical large applications on these systems. + * In practice, the slower/faster the device at hand is, the more/less it + * takes to load applications with respect to the reference device. + * Accordingly, the longer/shorter BFQ grants weight raising to interactive + * applications. + * + * BFQ uses four different reference pairs (R, T), depending on: + * . whether the device is rotational or non-rotational; + * . whether the device is slow, such as old or portable HDDs, as well as + * SD cards, or fast, such as newer HDDs and SSDs. + * + * The device's speed class is dynamically (re)detected in + * bfq_update_peak_rate() every time the estimated peak rate is updated. + * + * In the following definitions, R_slow[0]/R_fast[0] and + * T_slow[0]/T_fast[0] are the reference values for a slow/fast + * rotational device, whereas R_slow[1]/R_fast[1] and + * T_slow[1]/T_fast[1] are the reference values for a slow/fast + * non-rotational device. Finally, device_speed_thresh are the + * thresholds used to switch between speed classes. The reference + * rates are not the actual peak rates of the devices used as a + * reference, but slightly lower values. The reason for using these + * slightly lower values is that the peak-rate estimator tends to + * yield slightly lower values than the actual peak rate (it can yield + * the actual peak rate only if there is only one process doing I/O, + * and the process does sequential I/O). + * + * Both the reference peak rates and the thresholds are measured in + * sectors/usec, left-shifted by BFQ_RATE_SHIFT. + */ +static int R_slow[2] = {1000, 10700}; +static int R_fast[2] = {14000, 33000}; +/* + * To improve readability, a conversion function is used to initialize the + * following arrays, which entails that they can be initialized only in a + * function. + */ +static int T_slow[2]; +static int T_fast[2]; +static int device_speed_thresh[2]; + +#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ + { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) + +#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) +#define RQ_BFQQ(rq) ((rq)->elv.priv[1]) + +static void bfq_schedule_dispatch(struct bfq_data *bfqd); + +#include "bfq-ioc.c" +#include "bfq-sched.c" +#include "bfq-cgroup-included.c" + +#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE) +#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT) + +#define bfq_sample_valid(samples) ((samples) > 80) + +/* + * Scheduler run of queue, if there are requests pending and no one in the + * driver that will restart queueing. + */ +static void bfq_schedule_dispatch(struct bfq_data *bfqd) +{ + if (bfqd->queued != 0) { + bfq_log(bfqd, "schedule dispatch"); + kblockd_schedule_work(&bfqd->unplug_work); + } +} + +/* + * Lifted from AS - choose which of rq1 and rq2 that is best served now. + * We choose the request that is closesr to the head right now. Distance + * behind the head is penalized and only allowed to a certain extent. + */ +static struct request *bfq_choose_req(struct bfq_data *bfqd, + struct request *rq1, + struct request *rq2, + sector_t last) +{ + sector_t s1, s2, d1 = 0, d2 = 0; + unsigned long back_max; +#define BFQ_RQ1_WRAP 0x01 /* request 1 wraps */ +#define BFQ_RQ2_WRAP 0x02 /* request 2 wraps */ + unsigned int wrap = 0; /* bit mask: requests behind the disk head? */ + + if (!rq1 || rq1 == rq2) + return rq2; + if (!rq2) + return rq1; + + if (rq_is_sync(rq1) && !rq_is_sync(rq2)) + return rq1; + else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) + return rq2; + if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) + return rq1; + else if ((rq2->cmd_flags & REQ_META) && !(rq1->cmd_flags & REQ_META)) + return rq2; + + s1 = blk_rq_pos(rq1); + s2 = blk_rq_pos(rq2); + + /* + * By definition, 1KiB is 2 sectors. + */ + back_max = bfqd->bfq_back_max * 2; + + /* + * Strict one way elevator _except_ in the case where we allow + * short backward seeks which are biased as twice the cost of a + * similar forward seek. + */ + if (s1 >= last) + d1 = s1 - last; + else if (s1 + back_max >= last) + d1 = (last - s1) * bfqd->bfq_back_penalty; + else + wrap |= BFQ_RQ1_WRAP; + + if (s2 >= last) + d2 = s2 - last; + else if (s2 + back_max >= last) + d2 = (last - s2) * bfqd->bfq_back_penalty; + else + wrap |= BFQ_RQ2_WRAP; + + /* Found required data */ + + /* + * By doing switch() on the bit mask "wrap" we avoid having to + * check two variables for all permutations: --> faster! + */ + switch (wrap) { + case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ + if (d1 < d2) + return rq1; + else if (d2 < d1) + return rq2; + + if (s1 >= s2) + return rq1; + else + return rq2; + + case BFQ_RQ2_WRAP: + return rq1; + case BFQ_RQ1_WRAP: + return rq2; + case (BFQ_RQ1_WRAP|BFQ_RQ2_WRAP): /* both rqs wrapped */ + default: + /* + * Since both rqs are wrapped, + * start with the one that's further behind head + * (--> only *one* back seek required), + * since back seek takes more time than forward. + */ + if (s1 <= s2) + return rq1; + else + return rq2; + } +} + +static struct bfq_queue * +bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root, + sector_t sector, struct rb_node **ret_parent, + struct rb_node ***rb_link) +{ + struct rb_node **p, *parent; + struct bfq_queue *bfqq = NULL; + + parent = NULL; + p = &root->rb_node; + while (*p) { + struct rb_node **n; + + parent = *p; + bfqq = rb_entry(parent, struct bfq_queue, pos_node); + + /* + * Sort strictly based on sector. Smallest to the left, + * largest to the right. + */ + if (sector > blk_rq_pos(bfqq->next_rq)) + n = &(*p)->rb_right; + else if (sector < blk_rq_pos(bfqq->next_rq)) + n = &(*p)->rb_left; + else + break; + p = n; + bfqq = NULL; + } + + *ret_parent = parent; + if (rb_link) + *rb_link = p; + + bfq_log(bfqd, "rq_pos_tree_lookup %llu: returning %d", + (unsigned long long) sector, + bfqq ? bfqq->pid : 0); + + return bfqq; +} + +static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct rb_node **p, *parent; + struct bfq_queue *__bfqq; + + if (bfqq->pos_root) { + rb_erase(&bfqq->pos_node, bfqq->pos_root); + bfqq->pos_root = NULL; + } + + if (bfq_class_idle(bfqq)) + return; + if (!bfqq->next_rq) + return; + + bfqq->pos_root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; + __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root, + blk_rq_pos(bfqq->next_rq), &parent, &p); + if (!__bfqq) { + rb_link_node(&bfqq->pos_node, parent, p); + rb_insert_color(&bfqq->pos_node, bfqq->pos_root); + } else + bfqq->pos_root = NULL; +} + +/* + * Tell whether there are active queues or groups with differentiated weights. + */ +static bool bfq_differentiated_weights(struct bfq_data *bfqd) +{ + /* + * For weights to differ, at least one of the trees must contain + * at least two nodes. + */ + return (!RB_EMPTY_ROOT(&bfqd->queue_weights_tree) && + (bfqd->queue_weights_tree.rb_node->rb_left || + bfqd->queue_weights_tree.rb_node->rb_right) +#ifdef BFQ_GROUP_IOSCHED_ENABLED + ) || + (!RB_EMPTY_ROOT(&bfqd->group_weights_tree) && + (bfqd->group_weights_tree.rb_node->rb_left || + bfqd->group_weights_tree.rb_node->rb_right) +#endif + ); +} + +/* + * The following function returns true if every queue must receive the + * same share of the throughput (this condition is used when deciding + * whether idling may be disabled, see the comments in the function + * bfq_bfqq_may_idle()). + * + * Such a scenario occurs when: + * 1) all active queues have the same weight, + * 2) all active groups at the same level in the groups tree have the same + * weight, + * 3) all active groups at the same level in the groups tree have the same + * number of children. + * + * Unfortunately, keeping the necessary state for evaluating exactly the + * above symmetry conditions would be quite complex and time-consuming. + * Therefore this function evaluates, instead, the following stronger + * sub-conditions, for which it is much easier to maintain the needed + * state: + * 1) all active queues have the same weight, + * 2) all active groups have the same weight, + * 3) all active groups have at most one active child each. + * In particular, the last two conditions are always true if hierarchical + * support and the cgroups interface are not enabled, thus no state needs + * to be maintained in this case. + */ +static bool bfq_symmetric_scenario(struct bfq_data *bfqd) +{ + return !bfq_differentiated_weights(bfqd); +} + +/* + * If the weight-counter tree passed as input contains no counter for + * the weight of the input entity, then add that counter; otherwise just + * increment the existing counter. + * + * Note that weight-counter trees contain few nodes in mostly symmetric + * scenarios. For example, if all queues have the same weight, then the + * weight-counter tree for the queues may contain at most one node. + * This holds even if low_latency is on, because weight-raised queues + * are not inserted in the tree. + * In most scenarios, the rate at which nodes are created/destroyed + * should be low too. + */ +static void bfq_weights_tree_add(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root) +{ + struct rb_node **new = &(root->rb_node), *parent = NULL; + + /* + * Do not insert if the entity is already associated with a + * counter, which happens if: + * 1) the entity is associated with a queue, + * 2) a request arrival has caused the queue to become both + * non-weight-raised, and hence change its weight, and + * backlogged; in this respect, each of the two events + * causes an invocation of this function, + * 3) this is the invocation of this function caused by the + * second event. This second invocation is actually useless, + * and we handle this fact by exiting immediately. More + * efficient or clearer solutions might possibly be adopted. + */ + if (entity->weight_counter) + return; + + while (*new) { + struct bfq_weight_counter *__counter = container_of(*new, + struct bfq_weight_counter, + weights_node); + parent = *new; + + if (entity->weight == __counter->weight) { + entity->weight_counter = __counter; + goto inc_counter; + } + if (entity->weight < __counter->weight) + new = &((*new)->rb_left); + else + new = &((*new)->rb_right); + } + + entity->weight_counter = kzalloc(sizeof(struct bfq_weight_counter), + GFP_ATOMIC); + + /* + * In the unlucky event of an allocation failure, we just + * exit. This will cause the weight of entity to not be + * considered in bfq_differentiated_weights, which, in its + * turn, causes the scenario to be deemed wrongly symmetric in + * case entity's weight would have been the only weight making + * the scenario asymmetric. On the bright side, no unbalance + * will however occur when entity becomes inactive again (the + * invocation of this function is triggered by an activation + * of entity). In fact, bfq_weights_tree_remove does nothing + * if !entity->weight_counter. + */ + if (unlikely(!entity->weight_counter)) + return; + + entity->weight_counter->weight = entity->weight; + rb_link_node(&entity->weight_counter->weights_node, parent, new); + rb_insert_color(&entity->weight_counter->weights_node, root); + +inc_counter: + entity->weight_counter->num_active++; +} + +/* + * Decrement the weight counter associated with the entity, and, if the + * counter reaches 0, remove the counter from the tree. + * See the comments to the function bfq_weights_tree_add() for considerations + * about overhead. + */ +static void bfq_weights_tree_remove(struct bfq_data *bfqd, + struct bfq_entity *entity, + struct rb_root *root) +{ + if (!entity->weight_counter) + return; + + BUG_ON(RB_EMPTY_ROOT(root)); + BUG_ON(entity->weight_counter->weight != entity->weight); + + BUG_ON(!entity->weight_counter->num_active); + entity->weight_counter->num_active--; + if (entity->weight_counter->num_active > 0) + goto reset_entity_pointer; + + rb_erase(&entity->weight_counter->weights_node, root); + kfree(entity->weight_counter); + +reset_entity_pointer: + entity->weight_counter = NULL; +} + +/* + * Return expired entry, or NULL to just start from scratch in rbtree. + */ +static struct request *bfq_check_fifo(struct bfq_queue *bfqq, + struct request *last) +{ + struct request *rq; + + if (bfq_bfqq_fifo_expire(bfqq)) + return NULL; + + bfq_mark_bfqq_fifo_expire(bfqq); + + rq = rq_entry_fifo(bfqq->fifo.next); + + if (rq == last || ktime_get_ns() < rq->fifo_time) + return NULL; + + bfq_log_bfqq(bfqq->bfqd, bfqq, "check_fifo: returned %p", rq); + BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); + return rq; +} + +static struct request *bfq_find_next_rq(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + struct request *last) +{ + struct rb_node *rbnext = rb_next(&last->rb_node); + struct rb_node *rbprev = rb_prev(&last->rb_node); + struct request *next, *prev = NULL; + + BUG_ON(list_empty(&bfqq->fifo)); + + /* Follow expired path, else get first next available. */ + next = bfq_check_fifo(bfqq, last); + if (next) { + BUG_ON(next == last); + return next; + } + + BUG_ON(RB_EMPTY_NODE(&last->rb_node)); + + if (rbprev) + prev = rb_entry_rq(rbprev); + + if (rbnext) + next = rb_entry_rq(rbnext); + else { + rbnext = rb_first(&bfqq->sort_list); + if (rbnext && rbnext != &last->rb_node) + next = rb_entry_rq(rbnext); + } + + return bfq_choose_req(bfqd, next, prev, blk_rq_pos(last)); +} + +/* see the definition of bfq_async_charge_factor for details */ +static unsigned long bfq_serv_to_charge(struct request *rq, + struct bfq_queue *bfqq) +{ + if (bfq_bfqq_sync(bfqq) || bfqq->wr_coeff > 1) + return blk_rq_sectors(rq); + + /* + * If there are no weight-raised queues, then amplify service + * by just the async charge factor; otherwise amplify service + * by twice the async charge factor, to further reduce latency + * for weight-raised queues. + */ + if (bfqq->bfqd->wr_busy_queues == 0) + return blk_rq_sectors(rq) * bfq_async_charge_factor; + + return blk_rq_sectors(rq) * 2 * bfq_async_charge_factor; +} + +/** + * bfq_updated_next_req - update the queue after a new next_rq selection. + * @bfqd: the device data the queue belongs to. + * @bfqq: the queue to update. + * + * If the first request of a queue changes we make sure that the queue + * has enough budget to serve at least its first request (if the + * request has grown). We do this because if the queue has not enough + * budget for its first request, it has to go through two dispatch + * rounds to actually get it dispatched. + */ +static void bfq_updated_next_req(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + struct bfq_service_tree *st = bfq_entity_service_tree(entity); + struct request *next_rq = bfqq->next_rq; + unsigned long new_budget; + + if (!next_rq) + return; + + if (bfqq == bfqd->in_service_queue) + /* + * In order not to break guarantees, budgets cannot be + * changed after an entity has been selected. + */ + return; + + BUG_ON(entity->tree != &st->active); + BUG_ON(entity == entity->sched_data->in_service_entity); + + new_budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)); + if (entity->budget != new_budget) { + entity->budget = new_budget; + bfq_log_bfqq(bfqd, bfqq, "updated next rq: new budget %lu", + new_budget); + bfq_requeue_bfqq(bfqd, bfqq, false); + } +} + +static unsigned int bfq_wr_duration(struct bfq_data *bfqd) +{ + u64 dur; + + if (bfqd->bfq_wr_max_time > 0) + return bfqd->bfq_wr_max_time; + + dur = bfqd->RT_prod; + do_div(dur, bfqd->peak_rate); + + /* + * Limit duration between 3 and 13 seconds. Tests show that + * higher values than 13 seconds often yield the opposite of + * the desired result, i.e., worsen responsiveness by letting + * non-interactive and non-soft-real-time applications + * preserve weight raising for a too long time interval. + * + * On the other end, lower values than 3 seconds make it + * difficult for most interactive tasks to complete their jobs + * before weight-raising finishes. + */ + if (dur > msecs_to_jiffies(13000)) + dur = msecs_to_jiffies(13000); + else if (dur < msecs_to_jiffies(3000)) + dur = msecs_to_jiffies(3000); + + return dur; +} + +static void +bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, + struct bfq_io_cq *bic, bool bfq_already_existing) +{ + unsigned int old_wr_coeff; + bool busy = bfq_already_existing && bfq_bfqq_busy(bfqq); + + if (bic->saved_has_short_ttime) + bfq_mark_bfqq_has_short_ttime(bfqq); + else + bfq_clear_bfqq_has_short_ttime(bfqq); + + if (bic->saved_IO_bound) + bfq_mark_bfqq_IO_bound(bfqq); + else + bfq_clear_bfqq_IO_bound(bfqq); + + if (unlikely(busy)) + old_wr_coeff = bfqq->wr_coeff; + + bfqq->wr_coeff = bic->saved_wr_coeff; + bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt; + BUG_ON(time_is_after_jiffies(bfqq->wr_start_at_switch_to_srt)); + bfqq->last_wr_start_finish = bic->saved_last_wr_start_finish; + bfqq->wr_cur_max_time = bic->saved_wr_cur_max_time; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); + + if (bfqq->wr_coeff > 1 && (bfq_bfqq_in_large_burst(bfqq) || + time_is_before_jiffies(bfqq->last_wr_start_finish + + bfqq->wr_cur_max_time))) { + bfq_log_bfqq(bfqq->bfqd, bfqq, + "resume state: switching off wr (%lu + %lu < %lu)", + bfqq->last_wr_start_finish, bfqq->wr_cur_max_time, + jiffies); + + bfqq->wr_coeff = 1; + } + + /* make sure weight will be updated, however we got here */ + bfqq->entity.prio_changed = 1; + + if (likely(!busy)) + return; + + if (old_wr_coeff == 1 && bfqq->wr_coeff > 1) { + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + } else if (old_wr_coeff > 1 && bfqq->wr_coeff == 1) { + bfqd->wr_busy_queues--; + BUG_ON(bfqd->wr_busy_queues < 0); + } +} + +static int bfqq_process_refs(struct bfq_queue *bfqq) +{ + int process_refs, io_refs; + + lockdep_assert_held(bfqq->bfqd->queue->queue_lock); + + io_refs = bfqq->allocated[READ] + bfqq->allocated[WRITE]; + process_refs = bfqq->ref - io_refs - bfqq->entity.on_st; + BUG_ON(process_refs < 0); + return process_refs; +} + +/* Empty burst list and add just bfqq (see comments to bfq_handle_burst) */ +static void bfq_reset_burst_list(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct bfq_queue *item; + struct hlist_node *n; + + hlist_for_each_entry_safe(item, n, &bfqd->burst_list, burst_list_node) + hlist_del_init(&item->burst_list_node); + hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); + bfqd->burst_size = 1; + bfqd->burst_parent_entity = bfqq->entity.parent; +} + +/* Add bfqq to the list of queues in current burst (see bfq_handle_burst) */ +static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + /* Increment burst size to take into account also bfqq */ + bfqd->burst_size++; + + bfq_log_bfqq(bfqd, bfqq, "add_to_burst %d", bfqd->burst_size); + + BUG_ON(bfqd->burst_size > bfqd->bfq_large_burst_thresh); + + if (bfqd->burst_size == bfqd->bfq_large_burst_thresh) { + struct bfq_queue *pos, *bfqq_item; + struct hlist_node *n; + + /* + * Enough queues have been activated shortly after each + * other to consider this burst as large. + */ + bfqd->large_burst = true; + bfq_log_bfqq(bfqd, bfqq, "add_to_burst: large burst started"); + + /* + * We can now mark all queues in the burst list as + * belonging to a large burst. + */ + hlist_for_each_entry(bfqq_item, &bfqd->burst_list, + burst_list_node) { + bfq_mark_bfqq_in_large_burst(bfqq_item); + bfq_log_bfqq(bfqd, bfqq_item, "marked in large burst"); + } + bfq_mark_bfqq_in_large_burst(bfqq); + bfq_log_bfqq(bfqd, bfqq, "marked in large burst"); + + /* + * From now on, and until the current burst finishes, any + * new queue being activated shortly after the last queue + * was inserted in the burst can be immediately marked as + * belonging to a large burst. So the burst list is not + * needed any more. Remove it. + */ + hlist_for_each_entry_safe(pos, n, &bfqd->burst_list, + burst_list_node) + hlist_del_init(&pos->burst_list_node); + } else /* + * Burst not yet large: add bfqq to the burst list. Do + * not increment the ref counter for bfqq, because bfqq + * is removed from the burst list before freeing bfqq + * in put_queue. + */ + hlist_add_head(&bfqq->burst_list_node, &bfqd->burst_list); +} + +/* + * If many queues belonging to the same group happen to be created + * shortly after each other, then the processes associated with these + * queues have typically a common goal. In particular, bursts of queue + * creations are usually caused by services or applications that spawn + * many parallel threads/processes. Examples are systemd during boot, + * or git grep. To help these processes get their job done as soon as + * possible, it is usually better to not grant either weight-raising + * or device idling to their queues. + * + * In this comment we describe, firstly, the reasons why this fact + * holds, and, secondly, the next function, which implements the main + * steps needed to properly mark these queues so that they can then be + * treated in a different way. + * + * The above services or applications benefit mostly from a high + * throughput: the quicker the requests of the activated queues are + * cumulatively served, the sooner the target job of these queues gets + * completed. As a consequence, weight-raising any of these queues, + * which also implies idling the device for it, is almost always + * counterproductive. In most cases it just lowers throughput. + * + * On the other hand, a burst of queue creations may be caused also by + * the start of an application that does not consist of a lot of + * parallel I/O-bound threads. In fact, with a complex application, + * several short processes may need to be executed to start-up the + * application. In this respect, to start an application as quickly as + * possible, the best thing to do is in any case to privilege the I/O + * related to the application with respect to all other + * I/O. Therefore, the best strategy to start as quickly as possible + * an application that causes a burst of queue creations is to + * weight-raise all the queues created during the burst. This is the + * exact opposite of the best strategy for the other type of bursts. + * + * In the end, to take the best action for each of the two cases, the + * two types of bursts need to be distinguished. Fortunately, this + * seems relatively easy, by looking at the sizes of the bursts. In + * particular, we found a threshold such that only bursts with a + * larger size than that threshold are apparently caused by + * services or commands such as systemd or git grep. For brevity, + * hereafter we call just 'large' these bursts. BFQ *does not* + * weight-raise queues whose creation occurs in a large burst. In + * addition, for each of these queues BFQ performs or does not perform + * idling depending on which choice boosts the throughput more. The + * exact choice depends on the device and request pattern at + * hand. + * + * Unfortunately, false positives may occur while an interactive task + * is starting (e.g., an application is being started). The + * consequence is that the queues associated with the task do not + * enjoy weight raising as expected. Fortunately these false positives + * are very rare. They typically occur if some service happens to + * start doing I/O exactly when the interactive task starts. + * + * Turning back to the next function, it implements all the steps + * needed to detect the occurrence of a large burst and to properly + * mark all the queues belonging to it (so that they can then be + * treated in a different way). This goal is achieved by maintaining a + * "burst list" that holds, temporarily, the queues that belong to the + * burst in progress. The list is then used to mark these queues as + * belonging to a large burst if the burst does become large. The main + * steps are the following. + * + * . when the very first queue is created, the queue is inserted into the + * list (as it could be the first queue in a possible burst) + * + * . if the current burst has not yet become large, and a queue Q that does + * not yet belong to the burst is activated shortly after the last time + * at which a new queue entered the burst list, then the function appends + * Q to the burst list + * + * . if, as a consequence of the previous step, the burst size reaches + * the large-burst threshold, then + * + * . all the queues in the burst list are marked as belonging to a + * large burst + * + * . the burst list is deleted; in fact, the burst list already served + * its purpose (keeping temporarily track of the queues in a burst, + * so as to be able to mark them as belonging to a large burst in the + * previous sub-step), and now is not needed any more + * + * . the device enters a large-burst mode + * + * . if a queue Q that does not belong to the burst is created while + * the device is in large-burst mode and shortly after the last time + * at which a queue either entered the burst list or was marked as + * belonging to the current large burst, then Q is immediately marked + * as belonging to a large burst. + * + * . if a queue Q that does not belong to the burst is created a while + * later, i.e., not shortly after, than the last time at which a queue + * either entered the burst list or was marked as belonging to the + * current large burst, then the current burst is deemed as finished and: + * + * . the large-burst mode is reset if set + * + * . the burst list is emptied + * + * . Q is inserted in the burst list, as Q may be the first queue + * in a possible new burst (then the burst list contains just Q + * after this step). + */ +static void bfq_handle_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + /* + * If bfqq is already in the burst list or is part of a large + * burst, or finally has just been split, then there is + * nothing else to do. + */ + if (!hlist_unhashed(&bfqq->burst_list_node) || + bfq_bfqq_in_large_burst(bfqq) || + time_is_after_eq_jiffies(bfqq->split_time + + msecs_to_jiffies(10))) + return; + + /* + * If bfqq's creation happens late enough, or bfqq belongs to + * a different group than the burst group, then the current + * burst is finished, and related data structures must be + * reset. + * + * In this respect, consider the special case where bfqq is + * the very first queue created after BFQ is selected for this + * device. In this case, last_ins_in_burst and + * burst_parent_entity are not yet significant when we get + * here. But it is easy to verify that, whether or not the + * following condition is true, bfqq will end up being + * inserted into the burst list. In particular the list will + * happen to contain only bfqq. And this is exactly what has + * to happen, as bfqq may be the first queue of the first + * burst. + */ + if (time_is_before_jiffies(bfqd->last_ins_in_burst + + bfqd->bfq_burst_interval) || + bfqq->entity.parent != bfqd->burst_parent_entity) { + bfqd->large_burst = false; + bfq_reset_burst_list(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, + "handle_burst: late activation or different group"); + goto end; + } + + /* + * If we get here, then bfqq is being activated shortly after the + * last queue. So, if the current burst is also large, we can mark + * bfqq as belonging to this large burst immediately. + */ + if (bfqd->large_burst) { + bfq_log_bfqq(bfqd, bfqq, "handle_burst: marked in burst"); + bfq_mark_bfqq_in_large_burst(bfqq); + goto end; + } + + /* + * If we get here, then a large-burst state has not yet been + * reached, but bfqq is being activated shortly after the last + * queue. Then we add bfqq to the burst. + */ + bfq_add_to_burst(bfqd, bfqq); +end: + /* + * At this point, bfqq either has been added to the current + * burst or has caused the current burst to terminate and a + * possible new burst to start. In particular, in the second + * case, bfqq has become the first queue in the possible new + * burst. In both cases last_ins_in_burst needs to be moved + * forward. + */ + bfqd->last_ins_in_burst = jiffies; + +} + +static int bfq_bfqq_budget_left(struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + + return entity->budget - entity->service; +} + +/* + * If enough samples have been computed, return the current max budget + * stored in bfqd, which is dynamically updated according to the + * estimated disk peak rate; otherwise return the default max budget + */ +static int bfq_max_budget(struct bfq_data *bfqd) +{ + if (bfqd->budgets_assigned < bfq_stats_min_budgets) + return bfq_default_max_budget; + else + return bfqd->bfq_max_budget; +} + +/* + * Return min budget, which is a fraction of the current or default + * max budget (trying with 1/32) + */ +static int bfq_min_budget(struct bfq_data *bfqd) +{ + if (bfqd->budgets_assigned < bfq_stats_min_budgets) + return bfq_default_max_budget / 32; + else + return bfqd->bfq_max_budget / 32; +} + +static void bfq_bfqq_expire(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool compensate, + enum bfqq_expiration reason); + +/* + * The next function, invoked after the input queue bfqq switches from + * idle to busy, updates the budget of bfqq. The function also tells + * whether the in-service queue should be expired, by returning + * true. The purpose of expiring the in-service queue is to give bfqq + * the chance to possibly preempt the in-service queue, and the reason + * for preempting the in-service queue is to achieve one of the two + * goals below. + * + * 1. Guarantee to bfqq its reserved bandwidth even if bfqq has + * expired because it has remained idle. In particular, bfqq may have + * expired for one of the following two reasons: + * + * - BFQ_BFQQ_NO_MORE_REQUEST bfqq did not enjoy any device idling and + * did not make it to issue a new request before its last request + * was served; + * + * - BFQ_BFQQ_TOO_IDLE bfqq did enjoy device idling, but did not issue + * a new request before the expiration of the idling-time. + * + * Even if bfqq has expired for one of the above reasons, the process + * associated with the queue may be however issuing requests greedily, + * and thus be sensitive to the bandwidth it receives (bfqq may have + * remained idle for other reasons: CPU high load, bfqq not enjoying + * idling, I/O throttling somewhere in the path from the process to + * the I/O scheduler, ...). But if, after every expiration for one of + * the above two reasons, bfqq has to wait for the service of at least + * one full budget of another queue before being served again, then + * bfqq is likely to get a much lower bandwidth or resource time than + * its reserved ones. To address this issue, two countermeasures need + * to be taken. + * + * First, the budget and the timestamps of bfqq need to be updated in + * a special way on bfqq reactivation: they need to be updated as if + * bfqq did not remain idle and did not expire. In fact, if they are + * computed as if bfqq expired and remained idle until reactivation, + * then the process associated with bfqq is treated as if, instead of + * being greedy, it stopped issuing requests when bfqq remained idle, + * and restarts issuing requests only on this reactivation. In other + * words, the scheduler does not help the process recover the "service + * hole" between bfqq expiration and reactivation. As a consequence, + * the process receives a lower bandwidth than its reserved one. In + * contrast, to recover this hole, the budget must be updated as if + * bfqq was not expired at all before this reactivation, i.e., it must + * be set to the value of the remaining budget when bfqq was + * expired. Along the same line, timestamps need to be assigned the + * value they had the last time bfqq was selected for service, i.e., + * before last expiration. Thus timestamps need to be back-shifted + * with respect to their normal computation (see [1] for more details + * on this tricky aspect). + * + * Secondly, to allow the process to recover the hole, the in-service + * queue must be expired too, to give bfqq the chance to preempt it + * immediately. In fact, if bfqq has to wait for a full budget of the + * in-service queue to be completed, then it may become impossible to + * let the process recover the hole, even if the back-shifted + * timestamps of bfqq are lower than those of the in-service queue. If + * this happens for most or all of the holes, then the process may not + * receive its reserved bandwidth. In this respect, it is worth noting + * that, being the service of outstanding requests unpreemptible, a + * little fraction of the holes may however be unrecoverable, thereby + * causing a little loss of bandwidth. + * + * The last important point is detecting whether bfqq does need this + * bandwidth recovery. In this respect, the next function deems the + * process associated with bfqq greedy, and thus allows it to recover + * the hole, if: 1) the process is waiting for the arrival of a new + * request (which implies that bfqq expired for one of the above two + * reasons), and 2) such a request has arrived soon. The first + * condition is controlled through the flag non_blocking_wait_rq, + * while the second through the flag arrived_in_time. If both + * conditions hold, then the function computes the budget in the + * above-described special way, and signals that the in-service queue + * should be expired. Timestamp back-shifting is done later in + * __bfq_activate_entity. + * + * 2. Reduce latency. Even if timestamps are not backshifted to let + * the process associated with bfqq recover a service hole, bfqq may + * however happen to have, after being (re)activated, a lower finish + * timestamp than the in-service queue. That is, the next budget of + * bfqq may have to be completed before the one of the in-service + * queue. If this is the case, then preempting the in-service queue + * allows this goal to be achieved, apart from the unpreemptible, + * outstanding requests mentioned above. + * + * Unfortunately, regardless of which of the above two goals one wants + * to achieve, service trees need first to be updated to know whether + * the in-service queue must be preempted. To have service trees + * correctly updated, the in-service queue must be expired and + * rescheduled, and bfqq must be scheduled too. This is one of the + * most costly operations (in future versions, the scheduling + * mechanism may be re-designed in such a way to make it possible to + * know whether preemption is needed without needing to update service + * trees). In addition, queue preemptions almost always cause random + * I/O, and thus loss of throughput. Because of these facts, the next + * function adopts the following simple scheme to avoid both costly + * operations and too frequent preemptions: it requests the expiration + * of the in-service queue (unconditionally) only for queues that need + * to recover a hole, or that either are weight-raised or deserve to + * be weight-raised. + */ +static bool bfq_bfqq_update_budg_for_activation(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool arrived_in_time, + bool wr_or_deserves_wr) +{ + struct bfq_entity *entity = &bfqq->entity; + + if (bfq_bfqq_non_blocking_wait_rq(bfqq) && arrived_in_time) { + /* + * We do not clear the flag non_blocking_wait_rq here, as + * the latter is used in bfq_activate_bfqq to signal + * that timestamps need to be back-shifted (and is + * cleared right after). + */ + + /* + * In next assignment we rely on that either + * entity->service or entity->budget are not updated + * on expiration if bfqq is empty (see + * __bfq_bfqq_recalc_budget). Thus both quantities + * remain unchanged after such an expiration, and the + * following statement therefore assigns to + * entity->budget the remaining budget on such an + * expiration. For clarity, entity->service is not + * updated on expiration in any case, and, in normal + * operation, is reset only when bfqq is selected for + * service (see bfq_get_next_queue). + */ + BUG_ON(bfqq->max_budget < 0); + entity->budget = min_t(unsigned long, + bfq_bfqq_budget_left(bfqq), + bfqq->max_budget); + + BUG_ON(entity->budget < 0); + return true; + } + + BUG_ON(bfqq->max_budget < 0); + entity->budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(bfqq->next_rq, bfqq)); + BUG_ON(entity->budget < 0); + + bfq_clear_bfqq_non_blocking_wait_rq(bfqq); + return wr_or_deserves_wr; +} + +/* + * Return the farthest future time instant according to jiffies + * macros. + */ +static unsigned long bfq_greatest_from_now(void) +{ + return jiffies + MAX_JIFFY_OFFSET; +} + +/* + * Return the farthest past time instant according to jiffies + * macros. + */ +static unsigned long bfq_smallest_from_now(void) +{ + return jiffies - MAX_JIFFY_OFFSET; +} + +static void bfq_update_bfqq_wr_on_rq_arrival(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + unsigned int old_wr_coeff, + bool wr_or_deserves_wr, + bool interactive, + bool in_burst, + bool soft_rt) +{ + if (old_wr_coeff == 1 && wr_or_deserves_wr) { + /* start a weight-raising period */ + if (interactive) { + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + } else { + /* + * No interactive weight raising in progress + * here: assign minus infinity to + * wr_start_at_switch_to_srt, to make sure + * that, at the end of the soft-real-time + * weight raising periods that is starting + * now, no interactive weight-raising period + * may be wrongly considered as still in + * progress (and thus actually started by + * mistake). + */ + bfqq->wr_start_at_switch_to_srt = + bfq_smallest_from_now(); + bfqq->wr_coeff = bfqd->bfq_wr_coeff * + BFQ_SOFTRT_WEIGHT_FACTOR; + bfqq->wr_cur_max_time = + bfqd->bfq_wr_rt_max_time; + } + /* + * If needed, further reduce budget to make sure it is + * close to bfqq's backlog, so as to reduce the + * scheduling-error component due to a too large + * budget. Do not care about throughput consequences, + * but only about latency. Finally, do not assign a + * too small budget either, to avoid increasing + * latency by causing too frequent expirations. + */ + bfqq->entity.budget = min_t(unsigned long, + bfqq->entity.budget, + 2 * bfq_min_budget(bfqd)); + + bfq_log_bfqq(bfqd, bfqq, + "wrais starting at %lu, rais_max_time %u", + jiffies, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } else if (old_wr_coeff > 1) { + if (interactive) { /* update wr coeff and duration */ + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + } else if (in_burst) { + bfqq->wr_coeff = 1; + bfq_log_bfqq(bfqd, bfqq, + "wrais ending at %lu, rais_max_time %u", + jiffies, + jiffies_to_msecs(bfqq-> + wr_cur_max_time)); + } else if (soft_rt) { + /* + * The application is now or still meeting the + * requirements for being deemed soft rt. We + * can then correctly and safely (re)charge + * the weight-raising duration for the + * application with the weight-raising + * duration for soft rt applications. + * + * In particular, doing this recharge now, i.e., + * before the weight-raising period for the + * application finishes, reduces the probability + * of the following negative scenario: + * 1) the weight of a soft rt application is + * raised at startup (as for any newly + * created application), + * 2) since the application is not interactive, + * at a certain time weight-raising is + * stopped for the application, + * 3) at that time the application happens to + * still have pending requests, and hence + * is destined to not have a chance to be + * deemed soft rt before these requests are + * completed (see the comments to the + * function bfq_bfqq_softrt_next_start() + * for details on soft rt detection), + * 4) these pending requests experience a high + * latency because the application is not + * weight-raised while they are pending. + */ + if (bfqq->wr_cur_max_time != + bfqd->bfq_wr_rt_max_time) { + bfqq->wr_start_at_switch_to_srt = + bfqq->last_wr_start_finish; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); + + bfqq->wr_cur_max_time = + bfqd->bfq_wr_rt_max_time; + bfqq->wr_coeff = bfqd->bfq_wr_coeff * + BFQ_SOFTRT_WEIGHT_FACTOR; + bfq_log_bfqq(bfqd, bfqq, + "switching to soft_rt wr"); + } else + bfq_log_bfqq(bfqd, bfqq, + "moving forward soft_rt wr duration"); + bfqq->last_wr_start_finish = jiffies; + } + } +} + +static bool bfq_bfqq_idle_for_long_time(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + return bfqq->dispatched == 0 && + time_is_before_jiffies( + bfqq->budget_timeout + + bfqd->bfq_wr_min_idle_time); +} + +static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + int old_wr_coeff, + struct request *rq, + bool *interactive) +{ + bool soft_rt, in_burst, wr_or_deserves_wr, + bfqq_wants_to_preempt, + idle_for_long_time = bfq_bfqq_idle_for_long_time(bfqd, bfqq), + /* + * See the comments on + * bfq_bfqq_update_budg_for_activation for + * details on the usage of the next variable. + */ + arrived_in_time = ktime_get_ns() <= + RQ_BIC(rq)->ttime.last_end_request + + bfqd->bfq_slice_idle * 3; + + bfq_log_bfqq(bfqd, bfqq, + "bfq_add_request non-busy: " + "jiffies %lu, in_time %d, idle_long %d busyw %d " + "wr_coeff %u", + jiffies, arrived_in_time, + idle_for_long_time, + bfq_bfqq_non_blocking_wait_rq(bfqq), + old_wr_coeff); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + BUG_ON(bfqq == bfqd->in_service_queue); + bfqg_stats_update_io_add(bfqq_group(RQ_BFQQ(rq)), bfqq, rq->cmd_flags); + + /* + * bfqq deserves to be weight-raised if: + * - it is sync, + * - it does not belong to a large burst, + * - it has been idle for enough time or is soft real-time, + * - is linked to a bfq_io_cq (it is not shared in any sense) + */ + in_burst = bfq_bfqq_in_large_burst(bfqq); + soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && + !in_burst && + time_is_before_jiffies(bfqq->soft_rt_next_start); + *interactive = + !in_burst && + idle_for_long_time; + wr_or_deserves_wr = bfqd->low_latency && + (bfqq->wr_coeff > 1 || + (bfq_bfqq_sync(bfqq) && + bfqq->bic && (*interactive || soft_rt))); + + bfq_log_bfqq(bfqd, bfqq, + "bfq_add_request: " + "in_burst %d, " + "soft_rt %d (next %lu), inter %d, bic %p", + bfq_bfqq_in_large_burst(bfqq), soft_rt, + bfqq->soft_rt_next_start, + *interactive, + bfqq->bic); + + /* + * Using the last flag, update budget and check whether bfqq + * may want to preempt the in-service queue. + */ + bfqq_wants_to_preempt = + bfq_bfqq_update_budg_for_activation(bfqd, bfqq, + arrived_in_time, + wr_or_deserves_wr); + + /* + * If bfqq happened to be activated in a burst, but has been + * idle for much more than an interactive queue, then we + * assume that, in the overall I/O initiated in the burst, the + * I/O associated with bfqq is finished. So bfqq does not need + * to be treated as a queue belonging to a burst + * anymore. Accordingly, we reset bfqq's in_large_burst flag + * if set, and remove bfqq from the burst list if it's + * there. We do not decrement burst_size, because the fact + * that bfqq does not need to belong to the burst list any + * more does not invalidate the fact that bfqq was created in + * a burst. + */ + if (likely(!bfq_bfqq_just_created(bfqq)) && + idle_for_long_time && + time_is_before_jiffies( + bfqq->budget_timeout + + msecs_to_jiffies(10000))) { + hlist_del_init(&bfqq->burst_list_node); + bfq_clear_bfqq_in_large_burst(bfqq); + } + + bfq_clear_bfqq_just_created(bfqq); + + if (!bfq_bfqq_IO_bound(bfqq)) { + if (arrived_in_time) { + bfqq->requests_within_timer++; + if (bfqq->requests_within_timer >= + bfqd->bfq_requests_within_timer) + bfq_mark_bfqq_IO_bound(bfqq); + } else + bfqq->requests_within_timer = 0; + bfq_log_bfqq(bfqd, bfqq, "requests in time %d", + bfqq->requests_within_timer); + } + + if (bfqd->low_latency) { + if (unlikely(time_is_after_jiffies(bfqq->split_time))) + /* wraparound */ + bfqq->split_time = + jiffies - bfqd->bfq_wr_min_idle_time - 1; + + if (time_is_before_jiffies(bfqq->split_time + + bfqd->bfq_wr_min_idle_time)) { + bfq_update_bfqq_wr_on_rq_arrival(bfqd, bfqq, + old_wr_coeff, + wr_or_deserves_wr, + *interactive, + in_burst, + soft_rt); + + if (old_wr_coeff != bfqq->wr_coeff) + bfqq->entity.prio_changed = 1; + } + } + + bfqq->last_idle_bklogged = jiffies; + bfqq->service_from_backlogged = 0; + bfq_clear_bfqq_softrt_update(bfqq); + + bfq_add_bfqq_busy(bfqd, bfqq); + + /* + * Expire in-service queue only if preemption may be needed + * for guarantees. In this respect, the function + * next_queue_may_preempt just checks a simple, necessary + * condition, and not a sufficient condition based on + * timestamps. In fact, for the latter condition to be + * evaluated, timestamps would need first to be updated, and + * this operation is quite costly (see the comments on the + * function bfq_bfqq_update_budg_for_activation). + */ + if (bfqd->in_service_queue && bfqq_wants_to_preempt && + bfqd->in_service_queue->wr_coeff < bfqq->wr_coeff && + next_queue_may_preempt(bfqd)) { + struct bfq_queue *in_serv = + bfqd->in_service_queue; + BUG_ON(in_serv == bfqq); + + bfq_bfqq_expire(bfqd, bfqd->in_service_queue, + false, BFQ_BFQQ_PREEMPTED); + } +} + +static void bfq_add_request(struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + struct bfq_data *bfqd = bfqq->bfqd; + struct request *next_rq, *prev; + unsigned int old_wr_coeff = bfqq->wr_coeff; + bool interactive = false; + + bfq_log_bfqq(bfqd, bfqq, "add_request: size %u %s", + blk_rq_sectors(rq), rq_is_sync(rq) ? "S" : "A"); + + if (bfqq->wr_coeff > 1) /* queue is being weight-raised */ + bfq_log_bfqq(bfqd, bfqq, + "raising period dur %u/%u msec, old coeff %u, w %d(%d)", + jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqq->wr_coeff, + bfqq->entity.weight, bfqq->entity.orig_weight); + + bfqq->queued[rq_is_sync(rq)]++; + bfqd->queued++; + + elv_rb_add(&bfqq->sort_list, rq); + + /* + * Check if this request is a better next-to-serve candidate. + */ + prev = bfqq->next_rq; + next_rq = bfq_choose_req(bfqd, bfqq->next_rq, rq, bfqd->last_position); + BUG_ON(!next_rq); + bfqq->next_rq = next_rq; + + /* + * Adjust priority tree position, if next_rq changes. + */ + if (prev != bfqq->next_rq) + bfq_pos_tree_add_move(bfqd, bfqq); + + if (!bfq_bfqq_busy(bfqq)) /* switching to busy ... */ + bfq_bfqq_handle_idle_busy_switch(bfqd, bfqq, old_wr_coeff, + rq, &interactive); + else { + if (bfqd->low_latency && old_wr_coeff == 1 && !rq_is_sync(rq) && + time_is_before_jiffies( + bfqq->last_wr_start_finish + + bfqd->bfq_wr_min_inter_arr_async)) { + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, bfqq, + "non-idle wrais starting, " + "wr_max_time %u wr_busy %d", + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqd->wr_busy_queues); + } + if (prev != bfqq->next_rq) + bfq_updated_next_req(bfqd, bfqq); + } + + /* + * Assign jiffies to last_wr_start_finish in the following + * cases: + * + * . if bfqq is not going to be weight-raised, because, for + * non weight-raised queues, last_wr_start_finish stores the + * arrival time of the last request; as of now, this piece + * of information is used only for deciding whether to + * weight-raise async queues + * + * . if bfqq is not weight-raised, because, if bfqq is now + * switching to weight-raised, then last_wr_start_finish + * stores the time when weight-raising starts + * + * . if bfqq is interactive, because, regardless of whether + * bfqq is currently weight-raised, the weight-raising + * period must start or restart (this case is considered + * separately because it is not detected by the above + * conditions, if bfqq is already weight-raised) + * + * last_wr_start_finish has to be updated also if bfqq is soft + * real-time, because the weight-raising period is constantly + * restarted on idle-to-busy transitions for these queues, but + * this is already done in bfq_bfqq_handle_idle_busy_switch if + * needed. + */ + if (bfqd->low_latency && + (old_wr_coeff == 1 || bfqq->wr_coeff == 1 || interactive)) + bfqq->last_wr_start_finish = jiffies; +} + +static struct request *bfq_find_rq_fmerge(struct bfq_data *bfqd, + struct bio *bio) +{ + struct task_struct *tsk = current; + struct bfq_io_cq *bic; + struct bfq_queue *bfqq; + + bic = bfq_bic_lookup(bfqd, tsk->io_context); + if (!bic) + return NULL; + + bfqq = bic_to_bfqq(bic, op_is_sync(bio->bi_opf)); + if (bfqq) + return elv_rb_find(&bfqq->sort_list, bio_end_sector(bio)); + + return NULL; +} + +static sector_t get_sdist(sector_t last_pos, struct request *rq) +{ + sector_t sdist = 0; + + if (last_pos) { + if (last_pos < blk_rq_pos(rq)) + sdist = blk_rq_pos(rq) - last_pos; + else + sdist = last_pos - blk_rq_pos(rq); + } + + return sdist; +} + +static void bfq_activate_request(struct request_queue *q, struct request *rq) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + bfqd->rq_in_driver++; +} + +static void bfq_deactivate_request(struct request_queue *q, struct request *rq) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + + BUG_ON(bfqd->rq_in_driver == 0); + bfqd->rq_in_driver--; +} + +static void bfq_remove_request(struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + struct bfq_data *bfqd = bfqq->bfqd; + const int sync = rq_is_sync(rq); + + BUG_ON(bfqq->entity.service > bfqq->entity.budget && + bfqq == bfqd->in_service_queue); + + if (bfqq->next_rq == rq) { + bfqq->next_rq = bfq_find_next_rq(bfqd, bfqq, rq); + bfq_updated_next_req(bfqd, bfqq); + } + + if (rq->queuelist.prev != &rq->queuelist) + list_del_init(&rq->queuelist); + BUG_ON(bfqq->queued[sync] == 0); + bfqq->queued[sync]--; + bfqd->queued--; + elv_rb_del(&bfqq->sort_list, rq); + + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { + bfqq->next_rq = NULL; + + BUG_ON(bfqq->entity.budget < 0); + + if (bfq_bfqq_busy(bfqq) && bfqq != bfqd->in_service_queue) { + BUG_ON(bfqq->ref < 2); /* referred by rq and on tree */ + bfq_del_bfqq_busy(bfqd, bfqq, false); + /* + * bfqq emptied. In normal operation, when + * bfqq is empty, bfqq->entity.service and + * bfqq->entity.budget must contain, + * respectively, the service received and the + * budget used last time bfqq emptied. These + * facts do not hold in this case, as at least + * this last removal occurred while bfqq is + * not in service. To avoid inconsistencies, + * reset both bfqq->entity.service and + * bfqq->entity.budget, if bfqq has still a + * process that may issue I/O requests to it. + */ + bfqq->entity.budget = bfqq->entity.service = 0; + } + + /* + * Remove queue from request-position tree as it is empty. + */ + if (bfqq->pos_root) { + rb_erase(&bfqq->pos_node, bfqq->pos_root); + bfqq->pos_root = NULL; + } + } + + if (rq->cmd_flags & REQ_META) { + BUG_ON(bfqq->meta_pending == 0); + bfqq->meta_pending--; + } + bfqg_stats_update_io_remove(bfqq_group(bfqq), rq->cmd_flags); +} + +static enum elv_merge bfq_merge(struct request_queue *q, struct request **req, + struct bio *bio) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct request *__rq; + + __rq = bfq_find_rq_fmerge(bfqd, bio); + if (__rq && elv_bio_merge_ok(__rq, bio)) { + *req = __rq; + return ELEVATOR_FRONT_MERGE; + } + + return ELEVATOR_NO_MERGE; +} + +static void bfq_merged_request(struct request_queue *q, struct request *req, + enum elv_merge type) +{ + if (type == ELEVATOR_FRONT_MERGE && + rb_prev(&req->rb_node) && + blk_rq_pos(req) < + blk_rq_pos(container_of(rb_prev(&req->rb_node), + struct request, rb_node))) { + struct bfq_queue *bfqq = RQ_BFQQ(req); + struct bfq_data *bfqd = bfqq->bfqd; + struct request *prev, *next_rq; + + /* Reposition request in its sort_list */ + elv_rb_del(&bfqq->sort_list, req); + elv_rb_add(&bfqq->sort_list, req); + /* Choose next request to be served for bfqq */ + prev = bfqq->next_rq; + next_rq = bfq_choose_req(bfqd, bfqq->next_rq, req, + bfqd->last_position); + BUG_ON(!next_rq); + bfqq->next_rq = next_rq; + /* + * If next_rq changes, update both the queue's budget to + * fit the new request and the queue's position in its + * rq_pos_tree. + */ + if (prev != bfqq->next_rq) { + bfq_updated_next_req(bfqd, bfqq); + bfq_pos_tree_add_move(bfqd, bfqq); + } + } +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static void bfq_bio_merged(struct request_queue *q, struct request *req, + struct bio *bio) +{ + bfqg_stats_update_io_merged(bfqq_group(RQ_BFQQ(req)), bio->bi_opf); +} +#endif + +static void bfq_merged_requests(struct request_queue *q, struct request *rq, + struct request *next) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq), *next_bfqq = RQ_BFQQ(next); + + /* + * If next and rq belong to the same bfq_queue and next is older + * than rq, then reposition rq in the fifo (by substituting next + * with rq). Otherwise, if next and rq belong to different + * bfq_queues, never reposition rq: in fact, we would have to + * reposition it with respect to next's position in its own fifo, + * which would most certainly be too expensive with respect to + * the benefits. + */ + if (bfqq == next_bfqq && + !list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && + next->fifo_time < rq->fifo_time) { + list_del_init(&rq->queuelist); + list_replace_init(&next->queuelist, &rq->queuelist); + rq->fifo_time = next->fifo_time; + } + + if (bfqq->next_rq == next) + bfqq->next_rq = rq; + + bfq_remove_request(next); + bfqg_stats_update_io_merged(bfqq_group(bfqq), next->cmd_flags); +} + +/* Must be called with bfqq != NULL */ +static void bfq_bfqq_end_wr(struct bfq_queue *bfqq) +{ + BUG_ON(!bfqq); + + if (bfq_bfqq_busy(bfqq)) { + bfqq->bfqd->wr_busy_queues--; + BUG_ON(bfqq->bfqd->wr_busy_queues < 0); + } + bfqq->wr_coeff = 1; + bfqq->wr_cur_max_time = 0; + bfqq->last_wr_start_finish = jiffies; + /* + * Trigger a weight change on the next invocation of + * __bfq_entity_update_weight_prio. + */ + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "end_wr: wrais ending at %lu, rais_max_time %u", + bfqq->last_wr_start_finish, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + bfq_log_bfqq(bfqq->bfqd, bfqq, "end_wr: wr_busy %d", + bfqq->bfqd->wr_busy_queues); +} + +static void bfq_end_wr_async_queues(struct bfq_data *bfqd, + struct bfq_group *bfqg) +{ + int i, j; + + for (i = 0; i < 2; i++) + for (j = 0; j < IOPRIO_BE_NR; j++) + if (bfqg->async_bfqq[i][j]) + bfq_bfqq_end_wr(bfqg->async_bfqq[i][j]); + if (bfqg->async_idle_bfqq) + bfq_bfqq_end_wr(bfqg->async_idle_bfqq); +} + +static void bfq_end_wr(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq; + + spin_lock_irq(bfqd->queue->queue_lock); + + list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) + bfq_bfqq_end_wr(bfqq); + list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) + bfq_bfqq_end_wr(bfqq); + bfq_end_wr_async(bfqd); + + spin_unlock_irq(bfqd->queue->queue_lock); +} + +static sector_t bfq_io_struct_pos(void *io_struct, bool request) +{ + if (request) + return blk_rq_pos(io_struct); + else + return ((struct bio *)io_struct)->bi_iter.bi_sector; +} + +static int bfq_rq_close_to_sector(void *io_struct, bool request, + sector_t sector) +{ + return abs(bfq_io_struct_pos(io_struct, request) - sector) <= + BFQQ_CLOSE_THR; +} + +static struct bfq_queue *bfqq_find_close(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + sector_t sector) +{ + struct rb_root *root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; + struct rb_node *parent, *node; + struct bfq_queue *__bfqq; + + if (RB_EMPTY_ROOT(root)) + return NULL; + + /* + * First, if we find a request starting at the end of the last + * request, choose it. + */ + __bfqq = bfq_rq_pos_tree_lookup(bfqd, root, sector, &parent, NULL); + if (__bfqq) + return __bfqq; + + /* + * If the exact sector wasn't found, the parent of the NULL leaf + * will contain the closest sector (rq_pos_tree sorted by + * next_request position). + */ + __bfqq = rb_entry(parent, struct bfq_queue, pos_node); + if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) + return __bfqq; + + if (blk_rq_pos(__bfqq->next_rq) < sector) + node = rb_next(&__bfqq->pos_node); + else + node = rb_prev(&__bfqq->pos_node); + if (!node) + return NULL; + + __bfqq = rb_entry(node, struct bfq_queue, pos_node); + if (bfq_rq_close_to_sector(__bfqq->next_rq, true, sector)) + return __bfqq; + + return NULL; +} + +static struct bfq_queue *bfq_find_close_cooperator(struct bfq_data *bfqd, + struct bfq_queue *cur_bfqq, + sector_t sector) +{ + struct bfq_queue *bfqq; + + /* + * We shall notice if some of the queues are cooperating, + * e.g., working closely on the same area of the device. In + * that case, we can group them together and: 1) don't waste + * time idling, and 2) serve the union of their requests in + * the best possible order for throughput. + */ + bfqq = bfqq_find_close(bfqd, cur_bfqq, sector); + if (!bfqq || bfqq == cur_bfqq) + return NULL; + + return bfqq; +} + +static struct bfq_queue * +bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +{ + int process_refs, new_process_refs; + struct bfq_queue *__bfqq; + + /* + * If there are no process references on the new_bfqq, then it is + * unsafe to follow the ->new_bfqq chain as other bfqq's in the chain + * may have dropped their last reference (not just their last process + * reference). + */ + if (!bfqq_process_refs(new_bfqq)) + return NULL; + + /* Avoid a circular list and skip interim queue merges. */ + while ((__bfqq = new_bfqq->new_bfqq)) { + if (__bfqq == bfqq) + return NULL; + new_bfqq = __bfqq; + } + + process_refs = bfqq_process_refs(bfqq); + new_process_refs = bfqq_process_refs(new_bfqq); + /* + * If the process for the bfqq has gone away, there is no + * sense in merging the queues. + */ + if (process_refs == 0 || new_process_refs == 0) + return NULL; + + bfq_log_bfqq(bfqq->bfqd, bfqq, "scheduling merge with queue %d", + new_bfqq->pid); + + /* + * Merging is just a redirection: the requests of the process + * owning one of the two queues are redirected to the other queue. + * The latter queue, in its turn, is set as shared if this is the + * first time that the requests of some process are redirected to + * it. + * + * We redirect bfqq to new_bfqq and not the opposite, because we + * are in the context of the process owning bfqq, hence we have + * the io_cq of this process. So we can immediately configure this + * io_cq to redirect the requests of the process to new_bfqq. + * + * NOTE, even if new_bfqq coincides with the in-service queue, the + * io_cq of new_bfqq is not available, because, if the in-service + * queue is shared, bfqd->in_service_bic may not point to the + * io_cq of the in-service queue. + * Redirecting the requests of the process owning bfqq to the + * currently in-service queue is in any case the best option, as + * we feed the in-service queue with new requests close to the + * last request served and, by doing so, hopefully increase the + * throughput. + */ + bfqq->new_bfqq = new_bfqq; + new_bfqq->ref += process_refs; + return new_bfqq; +} + +static bool bfq_may_be_close_cooperator(struct bfq_queue *bfqq, + struct bfq_queue *new_bfqq) +{ + if (bfq_class_idle(bfqq) || bfq_class_idle(new_bfqq) || + (bfqq->ioprio_class != new_bfqq->ioprio_class)) + return false; + + /* + * If either of the queues has already been detected as seeky, + * then merging it with the other queue is unlikely to lead to + * sequential I/O. + */ + if (BFQQ_SEEKY(bfqq) || BFQQ_SEEKY(new_bfqq)) + return false; + + /* + * Interleaved I/O is known to be done by (some) applications + * only for reads, so it does not make sense to merge async + * queues. + */ + if (!bfq_bfqq_sync(bfqq) || !bfq_bfqq_sync(new_bfqq)) + return false; + + return true; +} + +/* + * If this function returns true, then bfqq cannot be merged. The idea + * is that true cooperation happens very early after processes start + * to do I/O. Usually, late cooperations are just accidental false + * positives. In case bfqq is weight-raised, such false positives + * would evidently degrade latency guarantees for bfqq. + */ +static bool wr_from_too_long(struct bfq_queue *bfqq) +{ + return bfqq->wr_coeff > 1 && + time_is_before_jiffies(bfqq->last_wr_start_finish + + msecs_to_jiffies(100)); +} + +/* + * Attempt to schedule a merge of bfqq with the currently in-service + * queue or with a close queue among the scheduled queues. Return + * NULL if no merge was scheduled, a pointer to the shared bfq_queue + * structure otherwise. + * + * The OOM queue is not allowed to participate to cooperation: in fact, since + * the requests temporarily redirected to the OOM queue could be redirected + * again to dedicated queues at any time, the state needed to correctly + * handle merging with the OOM queue would be quite complex and expensive + * to maintain. Besides, in such a critical condition as an out of memory, + * the benefits of queue merging may be little relevant, or even negligible. + * + * Weight-raised queues can be merged only if their weight-raising + * period has just started. In fact cooperating processes are usually + * started together. Thus, with this filter we avoid false positives + * that would jeopardize low-latency guarantees. + * + * WARNING: queue merging may impair fairness among non-weight raised + * queues, for at least two reasons: 1) the original weight of a + * merged queue may change during the merged state, 2) even being the + * weight the same, a merged queue may be bloated with many more + * requests than the ones produced by its originally-associated + * process. + */ +static struct bfq_queue * +bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, + void *io_struct, bool request) +{ + struct bfq_queue *in_service_bfqq, *new_bfqq; + + if (bfqq->new_bfqq) + return bfqq->new_bfqq; + + if (io_struct && wr_from_too_long(bfqq) && + likely(bfqq != &bfqd->oom_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have looked for coop, but bfq%d wr", + bfqq->pid); + + if (!io_struct || + wr_from_too_long(bfqq) || + unlikely(bfqq == &bfqd->oom_bfqq)) + return NULL; + + /* If there is only one backlogged queue, don't search. */ + if (bfqd->busy_queues == 1) + return NULL; + + in_service_bfqq = bfqd->in_service_queue; + + if (in_service_bfqq && in_service_bfqq != bfqq && + bfqd->in_service_bic && wr_from_too_long(in_service_bfqq) + && likely(in_service_bfqq == &bfqd->oom_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have tried merge with in-service-queue, but wr"); + + if (!in_service_bfqq || in_service_bfqq == bfqq || + !bfqd->in_service_bic || wr_from_too_long(in_service_bfqq) || + unlikely(in_service_bfqq == &bfqd->oom_bfqq)) + goto check_scheduled; + + if (bfq_rq_close_to_sector(io_struct, request, bfqd->last_position) && + bfqq->entity.parent == in_service_bfqq->entity.parent && + bfq_may_be_close_cooperator(bfqq, in_service_bfqq)) { + new_bfqq = bfq_setup_merge(bfqq, in_service_bfqq); + if (new_bfqq) + return new_bfqq; + } + /* + * Check whether there is a cooperator among currently scheduled + * queues. The only thing we need is that the bio/request is not + * NULL, as we need it to establish whether a cooperator exists. + */ +check_scheduled: + new_bfqq = bfq_find_close_cooperator(bfqd, bfqq, + bfq_io_struct_pos(io_struct, request)); + + BUG_ON(new_bfqq && bfqq->entity.parent != new_bfqq->entity.parent); + + if (new_bfqq && wr_from_too_long(new_bfqq) && + likely(new_bfqq != &bfqd->oom_bfqq) && + bfq_may_be_close_cooperator(bfqq, new_bfqq)) + bfq_log_bfqq(bfqd, bfqq, + "would have merged with bfq%d, but wr", + new_bfqq->pid); + + if (new_bfqq && !wr_from_too_long(new_bfqq) && + likely(new_bfqq != &bfqd->oom_bfqq) && + bfq_may_be_close_cooperator(bfqq, new_bfqq)) + return bfq_setup_merge(bfqq, new_bfqq); + + return NULL; +} + +static void bfq_bfqq_save_state(struct bfq_queue *bfqq) +{ + struct bfq_io_cq *bic = bfqq->bic; + + /* + * If !bfqq->bic, the queue is already shared or its requests + * have already been redirected to a shared queue; both idle window + * and weight raising state have already been saved. Do nothing. + */ + if (!bic) + return; + + bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq); + bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq); + bic->saved_in_large_burst = bfq_bfqq_in_large_burst(bfqq); + bic->was_in_burst_list = !hlist_unhashed(&bfqq->burst_list_node); + bic->saved_wr_coeff = bfqq->wr_coeff; + bic->saved_wr_start_at_switch_to_srt = bfqq->wr_start_at_switch_to_srt; + bic->saved_last_wr_start_finish = bfqq->last_wr_start_finish; + bic->saved_wr_cur_max_time = bfqq->wr_cur_max_time; + BUG_ON(time_is_after_jiffies(bfqq->last_wr_start_finish)); +} + +static void bfq_get_bic_reference(struct bfq_queue *bfqq) +{ + /* + * If bfqq->bic has a non-NULL value, the bic to which it belongs + * is about to begin using a shared bfq_queue. + */ + if (bfqq->bic) + atomic_long_inc(&bfqq->bic->icq.ioc->refcount); +} + +static void +bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, + struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +{ + bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", + (unsigned long) new_bfqq->pid); + /* Save weight raising and idle window of the merged queues */ + bfq_bfqq_save_state(bfqq); + bfq_bfqq_save_state(new_bfqq); + if (bfq_bfqq_IO_bound(bfqq)) + bfq_mark_bfqq_IO_bound(new_bfqq); + bfq_clear_bfqq_IO_bound(bfqq); + + /* + * If bfqq is weight-raised, then let new_bfqq inherit + * weight-raising. To reduce false positives, neglect the case + * where bfqq has just been created, but has not yet made it + * to be weight-raised (which may happen because EQM may merge + * bfqq even before bfq_add_request is executed for the first + * time for bfqq). Handling this case would however be very + * easy, thanks to the flag just_created. + */ + if (new_bfqq->wr_coeff == 1 && bfqq->wr_coeff > 1) { + new_bfqq->wr_coeff = bfqq->wr_coeff; + new_bfqq->wr_cur_max_time = bfqq->wr_cur_max_time; + new_bfqq->last_wr_start_finish = bfqq->last_wr_start_finish; + new_bfqq->wr_start_at_switch_to_srt = + bfqq->wr_start_at_switch_to_srt; + if (bfq_bfqq_busy(new_bfqq)) { + bfqd->wr_busy_queues++; + BUG_ON(bfqd->wr_busy_queues > bfqd->busy_queues); + } + + new_bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, new_bfqq, + "wr start after merge with %d, rais_max_time %u", + bfqq->pid, + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + if (bfqq->wr_coeff > 1) { /* bfqq has given its wr to new_bfqq */ + bfqq->wr_coeff = 1; + bfqq->entity.prio_changed = 1; + if (bfq_bfqq_busy(bfqq)) { + bfqd->wr_busy_queues--; + BUG_ON(bfqd->wr_busy_queues < 0); + } + + } + + bfq_log_bfqq(bfqd, new_bfqq, "merge_bfqqs: wr_busy %d", + bfqd->wr_busy_queues); + + /* + * Grab a reference to the bic, to prevent it from being destroyed + * before being possibly touched by a bfq_split_bfqq(). + */ + bfq_get_bic_reference(bfqq); + bfq_get_bic_reference(new_bfqq); + /* + * Merge queues (that is, let bic redirect its requests to new_bfqq) + */ + bic_set_bfqq(bic, new_bfqq, 1); + bfq_mark_bfqq_coop(new_bfqq); + /* + * new_bfqq now belongs to at least two bics (it is a shared queue): + * set new_bfqq->bic to NULL. bfqq either: + * - does not belong to any bic any more, and hence bfqq->bic must + * be set to NULL, or + * - is a queue whose owning bics have already been redirected to a + * different queue, hence the queue is destined to not belong to + * any bic soon and bfqq->bic is already NULL (therefore the next + * assignment causes no harm). + */ + new_bfqq->bic = NULL; + bfqq->bic = NULL; + /* release process reference to bfqq */ + bfq_put_queue(bfqq); +} + +static int bfq_allow_bio_merge(struct request_queue *q, struct request *rq, + struct bio *bio) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + bool is_sync = op_is_sync(bio->bi_opf); + struct bfq_io_cq *bic; + struct bfq_queue *bfqq, *new_bfqq; + + /* + * Disallow merge of a sync bio into an async request. + */ + if (is_sync && !rq_is_sync(rq)) + return false; + + /* + * Lookup the bfqq that this bio will be queued with. Allow + * merge only if rq is queued there. + * Queue lock is held here. + */ + bic = bfq_bic_lookup(bfqd, current->io_context); + if (!bic) + return false; + + bfqq = bic_to_bfqq(bic, is_sync); + /* + * We take advantage of this function to perform an early merge + * of the queues of possible cooperating processes. + */ + if (bfqq) { + new_bfqq = bfq_setup_cooperator(bfqd, bfqq, bio, false); + if (new_bfqq) { + bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); + /* + * If we get here, the bio will be queued in the + * shared queue, i.e., new_bfqq, so use new_bfqq + * to decide whether bio and rq can be merged. + */ + bfqq = new_bfqq; + } + } + + return bfqq == RQ_BFQQ(rq); +} + +static int bfq_allow_rq_merge(struct request_queue *q, struct request *rq, + struct request *next) +{ + return RQ_BFQQ(rq) == RQ_BFQQ(next); +} + +/* + * Set the maximum time for the in-service queue to consume its + * budget. This prevents seeky processes from lowering the throughput. + * In practice, a time-slice service scheme is used with seeky + * processes. + */ +static void bfq_set_budget_timeout(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + unsigned int timeout_coeff; + + if (bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time) + timeout_coeff = 1; + else + timeout_coeff = bfqq->entity.weight / bfqq->entity.orig_weight; + + bfqd->last_budget_start = ktime_get(); + + bfqq->budget_timeout = jiffies + + bfqd->bfq_timeout * timeout_coeff; + + bfq_log_bfqq(bfqd, bfqq, "set budget_timeout %u", + jiffies_to_msecs(bfqd->bfq_timeout * timeout_coeff)); +} + +static void __bfq_set_in_service_queue(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + if (bfqq) { + bfqg_stats_update_avg_queue_size(bfqq_group(bfqq)); + bfq_mark_bfqq_must_alloc(bfqq); + bfq_clear_bfqq_fifo_expire(bfqq); + + bfqd->budgets_assigned = (bfqd->budgets_assigned*7 + 256) / 8; + + BUG_ON(bfqq == bfqd->in_service_queue); + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + + if (time_is_before_jiffies(bfqq->last_wr_start_finish) && + bfqq->wr_coeff > 1 && + bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + time_is_before_jiffies(bfqq->budget_timeout)) { + /* + * For soft real-time queues, move the start + * of the weight-raising period forward by the + * time the queue has not received any + * service. Otherwise, a relatively long + * service delay is likely to cause the + * weight-raising period of the queue to end, + * because of the short duration of the + * weight-raising period of a soft real-time + * queue. It is worth noting that this move + * is not so dangerous for the other queues, + * because soft real-time queues are not + * greedy. + * + * To not add a further variable, we use the + * overloaded field budget_timeout to + * determine for how long the queue has not + * received service, i.e., how much time has + * elapsed since the queue expired. However, + * this is a little imprecise, because + * budget_timeout is set to jiffies if bfqq + * not only expires, but also remains with no + * request. + */ + if (time_after(bfqq->budget_timeout, + bfqq->last_wr_start_finish)) + bfqq->last_wr_start_finish += + jiffies - bfqq->budget_timeout; + else + bfqq->last_wr_start_finish = jiffies; + + if (time_is_after_jiffies(bfqq->last_wr_start_finish)) { + pr_crit( + "BFQ WARNING:last %lu budget %lu jiffies %lu", + bfqq->last_wr_start_finish, + bfqq->budget_timeout, + jiffies); + pr_crit("diff %lu", jiffies - + max_t(unsigned long, + bfqq->last_wr_start_finish, + bfqq->budget_timeout)); + bfqq->last_wr_start_finish = jiffies; + } + } + + bfq_set_budget_timeout(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, + "set_in_service_queue, cur-budget = %d", + bfqq->entity.budget); + } else + bfq_log(bfqd, "set_in_service_queue: NULL"); + + bfqd->in_service_queue = bfqq; +} + +/* + * Get and set a new queue for service. + */ +static struct bfq_queue *bfq_set_in_service_queue(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq = bfq_get_next_queue(bfqd); + + __bfq_set_in_service_queue(bfqd, bfqq); + return bfqq; +} + +static void bfq_arm_slice_timer(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq = bfqd->in_service_queue; + struct bfq_io_cq *bic; + u32 sl; + + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); + + /* Processes have exited, don't wait. */ + bic = bfqd->in_service_bic; + if (!bic || atomic_read(&bic->icq.ioc->active_ref) == 0) + return; + + bfq_mark_bfqq_wait_request(bfqq); + + /* + * We don't want to idle for seeks, but we do want to allow + * fair distribution of slice time for a process doing back-to-back + * seeks. So allow a little bit of time for him to submit a new rq. + * + * To prevent processes with (partly) seeky workloads from + * being too ill-treated, grant them a small fraction of the + * assigned budget before reducing the waiting time to + * BFQ_MIN_TT. This happened to help reduce latency. + */ + sl = bfqd->bfq_slice_idle; + /* + * Unless the queue is being weight-raised or the scenario is + * asymmetric, grant only minimum idle time if the queue + * is seeky. A long idling is preserved for a weight-raised + * queue, or, more in general, in an asymemtric scenario, + * because a long idling is needed for guaranteeing to a queue + * its reserved share of the throughput (in particular, it is + * needed if the queue has a higher weight than some other + * queue). + */ + if (BFQQ_SEEKY(bfqq) && bfqq->wr_coeff == 1 && + bfq_symmetric_scenario(bfqd)) + sl = min_t(u32, sl, BFQ_MIN_TT); + + bfqd->last_idling_start = ktime_get(); + hrtimer_start(&bfqd->idle_slice_timer, ns_to_ktime(sl), + HRTIMER_MODE_REL); + bfqg_stats_set_start_idle_time(bfqq_group(bfqq)); + bfq_log(bfqd, "arm idle: %ld/%ld ms", + sl / NSEC_PER_MSEC, bfqd->bfq_slice_idle / NSEC_PER_MSEC); +} + +/* + * In autotuning mode, max_budget is dynamically recomputed as the + * amount of sectors transferred in timeout at the estimated peak + * rate. This enables BFQ to utilize a full timeslice with a full + * budget, even if the in-service queue is served at peak rate. And + * this maximises throughput with sequential workloads. + */ +static unsigned long bfq_calc_max_budget(struct bfq_data *bfqd) +{ + return (u64)bfqd->peak_rate * USEC_PER_MSEC * + jiffies_to_msecs(bfqd->bfq_timeout)>>BFQ_RATE_SHIFT; +} + +/* + * Update parameters related to throughput and responsiveness, as a + * function of the estimated peak rate. See comments on + * bfq_calc_max_budget(), and on T_slow and T_fast arrays. + */ +static void update_thr_responsiveness_params(struct bfq_data *bfqd) +{ + int dev_type = blk_queue_nonrot(bfqd->queue); + + if (bfqd->bfq_user_max_budget == 0) { + bfqd->bfq_max_budget = + bfq_calc_max_budget(bfqd); + BUG_ON(bfqd->bfq_max_budget < 0); + bfq_log(bfqd, "new max_budget = %d", + bfqd->bfq_max_budget); + } + + if (bfqd->device_speed == BFQ_BFQD_FAST && + bfqd->peak_rate < device_speed_thresh[dev_type]) { + bfqd->device_speed = BFQ_BFQD_SLOW; + bfqd->RT_prod = R_slow[dev_type] * + T_slow[dev_type]; + } else if (bfqd->device_speed == BFQ_BFQD_SLOW && + bfqd->peak_rate > device_speed_thresh[dev_type]) { + bfqd->device_speed = BFQ_BFQD_FAST; + bfqd->RT_prod = R_fast[dev_type] * + T_fast[dev_type]; + } + + bfq_log(bfqd, +"dev_type %s dev_speed_class = %s (%llu sects/sec), thresh %llu setcs/sec", + dev_type == 0 ? "ROT" : "NONROT", + bfqd->device_speed == BFQ_BFQD_FAST ? "FAST" : "SLOW", + bfqd->device_speed == BFQ_BFQD_FAST ? + (USEC_PER_SEC*(u64)R_fast[dev_type])>>BFQ_RATE_SHIFT : + (USEC_PER_SEC*(u64)R_slow[dev_type])>>BFQ_RATE_SHIFT, + (USEC_PER_SEC*(u64)device_speed_thresh[dev_type])>> + BFQ_RATE_SHIFT); +} + +static void bfq_reset_rate_computation(struct bfq_data *bfqd, struct request *rq) +{ + if (rq != NULL) { /* new rq dispatch now, reset accordingly */ + bfqd->last_dispatch = bfqd->first_dispatch = ktime_get_ns() ; + bfqd->peak_rate_samples = 1; + bfqd->sequential_samples = 0; + bfqd->tot_sectors_dispatched = bfqd->last_rq_max_size = + blk_rq_sectors(rq); + } else /* no new rq dispatched, just reset the number of samples */ + bfqd->peak_rate_samples = 0; /* full re-init on next disp. */ + + bfq_log(bfqd, + "reset_rate_computation at end, sample %u/%u tot_sects %llu", + bfqd->peak_rate_samples, bfqd->sequential_samples, + bfqd->tot_sectors_dispatched); +} + +static void bfq_update_rate_reset(struct bfq_data *bfqd, struct request *rq) +{ + u32 rate, weight, divisor; + + /* + * For the convergence property to hold (see comments on + * bfq_update_peak_rate()) and for the assessment to be + * reliable, a minimum number of samples must be present, and + * a minimum amount of time must have elapsed. If not so, do + * not compute new rate. Just reset parameters, to get ready + * for a new evaluation attempt. + */ + if (bfqd->peak_rate_samples < BFQ_RATE_MIN_SAMPLES || + bfqd->delta_from_first < BFQ_RATE_MIN_INTERVAL) { + bfq_log(bfqd, + "update_rate_reset: only resetting, delta_first %lluus samples %d", + bfqd->delta_from_first>>10, bfqd->peak_rate_samples); + goto reset_computation; + } + + /* + * If a new request completion has occurred after last + * dispatch, then, to approximate the rate at which requests + * have been served by the device, it is more precise to + * extend the observation interval to the last completion. + */ + bfqd->delta_from_first = + max_t(u64, bfqd->delta_from_first, + bfqd->last_completion - bfqd->first_dispatch); + + BUG_ON(bfqd->delta_from_first == 0); + /* + * Rate computed in sects/usec, and not sects/nsec, for + * precision issues. + */ + rate = div64_ul(bfqd->tot_sectors_dispatched<delta_from_first, NSEC_PER_USEC)); + + bfq_log(bfqd, +"update_rate_reset: tot_sects %llu delta_first %lluus rate %llu sects/s (%d)", + bfqd->tot_sectors_dispatched, bfqd->delta_from_first>>10, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + rate > 20< 20M sectors/sec) + */ + if ((bfqd->sequential_samples < (3 * bfqd->peak_rate_samples)>>2 && + rate <= bfqd->peak_rate) || + rate > 20<peak_rate_samples, bfqd->sequential_samples, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + goto reset_computation; + } else { + bfq_log(bfqd, + "update_rate_reset: do update, samples %u/%u rate/peak %llu/%llu", + bfqd->peak_rate_samples, bfqd->sequential_samples, + ((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT), + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + } + + /* + * We have to update the peak rate, at last! To this purpose, + * we use a low-pass filter. We compute the smoothing constant + * of the filter as a function of the 'weight' of the new + * measured rate. + * + * As can be seen in next formulas, we define this weight as a + * quantity proportional to how sequential the workload is, + * and to how long the observation time interval is. + * + * The weight runs from 0 to 8. The maximum value of the + * weight, 8, yields the minimum value for the smoothing + * constant. At this minimum value for the smoothing constant, + * the measured rate contributes for half of the next value of + * the estimated peak rate. + * + * So, the first step is to compute the weight as a function + * of how sequential the workload is. Note that the weight + * cannot reach 9, because bfqd->sequential_samples cannot + * become equal to bfqd->peak_rate_samples, which, in its + * turn, holds true because bfqd->sequential_samples is not + * incremented for the first sample. + */ + weight = (9 * bfqd->sequential_samples) / bfqd->peak_rate_samples; + + /* + * Second step: further refine the weight as a function of the + * duration of the observation interval. + */ + weight = min_t(u32, 8, + div_u64(weight * bfqd->delta_from_first, + BFQ_RATE_REF_INTERVAL)); + + /* + * Divisor ranging from 10, for minimum weight, to 2, for + * maximum weight. + */ + divisor = 10 - weight; + BUG_ON(divisor == 0); + + /* + * Finally, update peak rate: + * + * peak_rate = peak_rate * (divisor-1) / divisor + rate / divisor + */ + bfqd->peak_rate *= divisor-1; + bfqd->peak_rate /= divisor; + rate /= divisor; /* smoothing constant alpha = 1/divisor */ + + bfq_log(bfqd, + "update_rate_reset: divisor %d tmp_peak_rate %llu tmp_rate %u", + divisor, + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT), + (u32)((USEC_PER_SEC*(u64)rate)>>BFQ_RATE_SHIFT)); + + BUG_ON(bfqd->peak_rate == 0); + BUG_ON(bfqd->peak_rate > 20<peak_rate += rate; + update_thr_responsiveness_params(bfqd); + BUG_ON(bfqd->peak_rate > 20<peak_rate_samples == 0) { /* first dispatch */ + bfq_log(bfqd, + "update_peak_rate: goto reset, samples %d", + bfqd->peak_rate_samples) ; + bfq_reset_rate_computation(bfqd, rq); + goto update_last_values; /* will add one sample */ + } + + /* + * Device idle for very long: the observation interval lasting + * up to this dispatch cannot be a valid observation interval + * for computing a new peak rate (similarly to the late- + * completion event in bfq_completed_request()). Go to + * update_rate_and_reset to have the following three steps + * taken: + * - close the observation interval at the last (previous) + * request dispatch or completion + * - compute rate, if possible, for that observation interval + * - start a new observation interval with this dispatch + */ + if (now_ns - bfqd->last_dispatch > 100*NSEC_PER_MSEC && + bfqd->rq_in_driver == 0) { + bfq_log(bfqd, +"update_peak_rate: jumping to updating&resetting delta_last %lluus samples %d", + (now_ns - bfqd->last_dispatch)>>10, + bfqd->peak_rate_samples) ; + goto update_rate_and_reset; + } + + /* Update sampling information */ + bfqd->peak_rate_samples++; + + if ((bfqd->rq_in_driver > 0 || + now_ns - bfqd->last_completion < BFQ_MIN_TT) + && get_sdist(bfqd->last_position, rq) < BFQQ_SEEK_THR) + bfqd->sequential_samples++; + + bfqd->tot_sectors_dispatched += blk_rq_sectors(rq); + + /* Reset max observed rq size every 32 dispatches */ + if (likely(bfqd->peak_rate_samples % 32)) + bfqd->last_rq_max_size = + max_t(u32, blk_rq_sectors(rq), bfqd->last_rq_max_size); + else + bfqd->last_rq_max_size = blk_rq_sectors(rq); + + bfqd->delta_from_first = now_ns - bfqd->first_dispatch; + + bfq_log(bfqd, + "update_peak_rate: added samples %u/%u tot_sects %llu delta_first %lluus", + bfqd->peak_rate_samples, bfqd->sequential_samples, + bfqd->tot_sectors_dispatched, + bfqd->delta_from_first>>10); + + /* Target observation interval not yet reached, go on sampling */ + if (bfqd->delta_from_first < BFQ_RATE_REF_INTERVAL) + goto update_last_values; + +update_rate_and_reset: + bfq_update_rate_reset(bfqd, rq); +update_last_values: + bfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); + bfqd->last_dispatch = now_ns; + + bfq_log(bfqd, + "update_peak_rate: delta_first %lluus last_pos %llu peak_rate %llu", + (now_ns - bfqd->first_dispatch)>>10, + (unsigned long long) bfqd->last_position, + ((USEC_PER_SEC*(u64)bfqd->peak_rate)>>BFQ_RATE_SHIFT)); + bfq_log(bfqd, + "update_peak_rate: samples at end %d", bfqd->peak_rate_samples); +} + +/* + * Move request from internal lists to the dispatch list of the request queue + */ +static void bfq_dispatch_insert(struct request_queue *q, struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + + /* + * For consistency, the next instruction should have been executed + * after removing the request from the queue and dispatching it. + * We execute instead this instruction before bfq_remove_request() + * (and hence introduce a temporary inconsistency), for efficiency. + * In fact, in a forced_dispatch, this prevents two counters related + * to bfqq->dispatched to risk to be uselessly decremented if bfqq + * is not in service, and then to be incremented again after + * incrementing bfqq->dispatched. + */ + bfqq->dispatched++; + bfq_update_peak_rate(q->elevator->elevator_data, rq); + + bfq_remove_request(rq); + elv_dispatch_sort(q, rq); +} + +static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + BUG_ON(bfqq != bfqd->in_service_queue); + + /* + * If this bfqq is shared between multiple processes, check + * to make sure that those processes are still issuing I/Os + * within the mean seek distance. If not, it may be time to + * break the queues apart again. + */ + if (bfq_bfqq_coop(bfqq) && BFQQ_SEEKY(bfqq)) + bfq_mark_bfqq_split_coop(bfqq); + + if (RB_EMPTY_ROOT(&bfqq->sort_list)) { + if (bfqq->dispatched == 0) + /* + * Overloading budget_timeout field to store + * the time at which the queue remains with no + * backlog and no outstanding request; used by + * the weight-raising mechanism. + */ + bfqq->budget_timeout = jiffies; + + bfq_del_bfqq_busy(bfqd, bfqq, true); + } else { + bfq_requeue_bfqq(bfqd, bfqq, true); + /* + * Resort priority tree of potential close cooperators. + */ + bfq_pos_tree_add_move(bfqd, bfqq); + } + + /* + * All in-service entities must have been properly deactivated + * or requeued before executing the next function, which + * resets all in-service entites as no more in service. + */ + __bfq_bfqd_reset_in_service(bfqd); +} + +/** + * __bfq_bfqq_recalc_budget - try to adapt the budget to the @bfqq behavior. + * @bfqd: device data. + * @bfqq: queue to update. + * @reason: reason for expiration. + * + * Handle the feedback on @bfqq budget at queue expiration. + * See the body for detailed comments. + */ +static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + enum bfqq_expiration reason) +{ + struct request *next_rq; + int budget, min_budget; + + BUG_ON(bfqq != bfqd->in_service_queue); + + min_budget = bfq_min_budget(bfqd); + + if (bfqq->wr_coeff == 1) + budget = bfqq->max_budget; + else /* + * Use a constant, low budget for weight-raised queues, + * to help achieve a low latency. Keep it slightly higher + * than the minimum possible budget, to cause a little + * bit fewer expirations. + */ + budget = 2 * min_budget; + + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %d, budg left %d", + bfqq->entity.budget, bfq_bfqq_budget_left(bfqq)); + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %d, min budg %d", + budget, bfq_min_budget(bfqd)); + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: sync %d, seeky %d", + bfq_bfqq_sync(bfqq), BFQQ_SEEKY(bfqd->in_service_queue)); + + if (bfq_bfqq_sync(bfqq) && bfqq->wr_coeff == 1) { + switch (reason) { + /* + * Caveat: in all the following cases we trade latency + * for throughput. + */ + case BFQ_BFQQ_TOO_IDLE: + /* + * This is the only case where we may reduce + * the budget: if there is no request of the + * process still waiting for completion, then + * we assume (tentatively) that the timer has + * expired because the batch of requests of + * the process could have been served with a + * smaller budget. Hence, betting that + * process will behave in the same way when it + * becomes backlogged again, we reduce its + * next budget. As long as we guess right, + * this budget cut reduces the latency + * experienced by the process. + * + * However, if there are still outstanding + * requests, then the process may have not yet + * issued its next request just because it is + * still waiting for the completion of some of + * the still outstanding ones. So in this + * subcase we do not reduce its budget, on the + * contrary we increase it to possibly boost + * the throughput, as discussed in the + * comments to the BUDGET_TIMEOUT case. + */ + if (bfqq->dispatched > 0) /* still outstanding reqs */ + budget = min(budget * 2, bfqd->bfq_max_budget); + else { + if (budget > 5 * min_budget) + budget -= 4 * min_budget; + else + budget = min_budget; + } + break; + case BFQ_BFQQ_BUDGET_TIMEOUT: + /* + * We double the budget here because it gives + * the chance to boost the throughput if this + * is not a seeky process (and has bumped into + * this timeout because of, e.g., ZBR). + */ + budget = min(budget * 2, bfqd->bfq_max_budget); + break; + case BFQ_BFQQ_BUDGET_EXHAUSTED: + /* + * The process still has backlog, and did not + * let either the budget timeout or the disk + * idling timeout expire. Hence it is not + * seeky, has a short thinktime and may be + * happy with a higher budget too. So + * definitely increase the budget of this good + * candidate to boost the disk throughput. + */ + budget = min(budget * 4, bfqd->bfq_max_budget); + break; + case BFQ_BFQQ_NO_MORE_REQUESTS: + /* + * For queues that expire for this reason, it + * is particularly important to keep the + * budget close to the actual service they + * need. Doing so reduces the timestamp + * misalignment problem described in the + * comments in the body of + * __bfq_activate_entity. In fact, suppose + * that a queue systematically expires for + * BFQ_BFQQ_NO_MORE_REQUESTS and presents a + * new request in time to enjoy timestamp + * back-shifting. The larger the budget of the + * queue is with respect to the service the + * queue actually requests in each service + * slot, the more times the queue can be + * reactivated with the same virtual finish + * time. It follows that, even if this finish + * time is pushed to the system virtual time + * to reduce the consequent timestamp + * misalignment, the queue unjustly enjoys for + * many re-activations a lower finish time + * than all newly activated queues. + * + * The service needed by bfqq is measured + * quite precisely by bfqq->entity.service. + * Since bfqq does not enjoy device idling, + * bfqq->entity.service is equal to the number + * of sectors that the process associated with + * bfqq requested to read/write before waiting + * for request completions, or blocking for + * other reasons. + */ + budget = max_t(int, bfqq->entity.service, min_budget); + break; + default: + return; + } + } else if (!bfq_bfqq_sync(bfqq)) + /* + * Async queues get always the maximum possible + * budget, as for them we do not care about latency + * (in addition, their ability to dispatch is limited + * by the charging factor). + */ + budget = bfqd->bfq_max_budget; + + bfqq->max_budget = budget; + + if (bfqd->budgets_assigned >= bfq_stats_min_budgets && + !bfqd->bfq_user_max_budget) + bfqq->max_budget = min(bfqq->max_budget, bfqd->bfq_max_budget); + + /* + * If there is still backlog, then assign a new budget, making + * sure that it is large enough for the next request. Since + * the finish time of bfqq must be kept in sync with the + * budget, be sure to call __bfq_bfqq_expire() *after* this + * update. + * + * If there is no backlog, then no need to update the budget; + * it will be updated on the arrival of a new request. + */ + next_rq = bfqq->next_rq; + if (next_rq) { + BUG_ON(reason == BFQ_BFQQ_TOO_IDLE || + reason == BFQ_BFQQ_NO_MORE_REQUESTS); + bfqq->entity.budget = max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)); + BUG_ON(!bfq_bfqq_busy(bfqq)); + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + } + + bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %d", + next_rq ? blk_rq_sectors(next_rq) : 0, + bfqq->entity.budget); +} + +/* + * Return true if the process associated with bfqq is "slow". The slow + * flag is used, in addition to the budget timeout, to reduce the + * amount of service provided to seeky processes, and thus reduce + * their chances to lower the throughput. More details in the comments + * on the function bfq_bfqq_expire(). + * + * An important observation is in order: as discussed in the comments + * on the function bfq_update_peak_rate(), with devices with internal + * queues, it is hard if ever possible to know when and for how long + * an I/O request is processed by the device (apart from the trivial + * I/O pattern where a new request is dispatched only after the + * previous one has been completed). This makes it hard to evaluate + * the real rate at which the I/O requests of each bfq_queue are + * served. In fact, for an I/O scheduler like BFQ, serving a + * bfq_queue means just dispatching its requests during its service + * slot (i.e., until the budget of the queue is exhausted, or the + * queue remains idle, or, finally, a timeout fires). But, during the + * service slot of a bfq_queue, around 100 ms at most, the device may + * be even still processing requests of bfq_queues served in previous + * service slots. On the opposite end, the requests of the in-service + * bfq_queue may be completed after the service slot of the queue + * finishes. + * + * Anyway, unless more sophisticated solutions are used + * (where possible), the sum of the sizes of the requests dispatched + * during the service slot of a bfq_queue is probably the only + * approximation available for the service received by the bfq_queue + * during its service slot. And this sum is the quantity used in this + * function to evaluate the I/O speed of a process. + */ +static bool bfq_bfqq_is_slow(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool compensate, enum bfqq_expiration reason, + unsigned long *delta_ms) +{ + ktime_t delta_ktime; + u32 delta_usecs; + bool slow = BFQQ_SEEKY(bfqq); /* if delta too short, use seekyness */ + + if (!bfq_bfqq_sync(bfqq)) + return false; + + if (compensate) + delta_ktime = bfqd->last_idling_start; + else + delta_ktime = ktime_get(); + delta_ktime = ktime_sub(delta_ktime, bfqd->last_budget_start); + delta_usecs = ktime_to_us(delta_ktime); + + /* don't use too short time intervals */ + if (delta_usecs < 1000) { + if (blk_queue_nonrot(bfqd->queue)) + /* + * give same worst-case guarantees as idling + * for seeky + */ + *delta_ms = BFQ_MIN_TT / NSEC_PER_MSEC; + else /* charge at least one seek */ + *delta_ms = bfq_slice_idle / NSEC_PER_MSEC; + + bfq_log(bfqd, "bfq_bfqq_is_slow: too short %u", delta_usecs); + + return slow; + } + + *delta_ms = delta_usecs / USEC_PER_MSEC; + + /* + * Use only long (> 20ms) intervals to filter out excessive + * spikes in service rate estimation. + */ + if (delta_usecs > 20000) { + /* + * Caveat for rotational devices: processes doing I/O + * in the slower disk zones tend to be slow(er) even + * if not seeky. In this respect, the estimated peak + * rate is likely to be an average over the disk + * surface. Accordingly, to not be too harsh with + * unlucky processes, a process is deemed slow only if + * its rate has been lower than half of the estimated + * peak rate. + */ + slow = bfqq->entity.service < bfqd->bfq_max_budget / 2; + bfq_log(bfqd, "bfq_bfqq_is_slow: relative rate %d/%d", + bfqq->entity.service, bfqd->bfq_max_budget); + } + + bfq_log_bfqq(bfqd, bfqq, "bfq_bfqq_is_slow: slow %d", slow); + + return slow; +} + +/* + * To be deemed as soft real-time, an application must meet two + * requirements. First, the application must not require an average + * bandwidth higher than the approximate bandwidth required to playback or + * record a compressed high-definition video. + * The next function is invoked on the completion of the last request of a + * batch, to compute the next-start time instant, soft_rt_next_start, such + * that, if the next request of the application does not arrive before + * soft_rt_next_start, then the above requirement on the bandwidth is met. + * + * The second requirement is that the request pattern of the application is + * isochronous, i.e., that, after issuing a request or a batch of requests, + * the application stops issuing new requests until all its pending requests + * have been completed. After that, the application may issue a new batch, + * and so on. + * For this reason the next function is invoked to compute + * soft_rt_next_start only for applications that meet this requirement, + * whereas soft_rt_next_start is set to infinity for applications that do + * not. + * + * Unfortunately, even a greedy application may happen to behave in an + * isochronous way if the CPU load is high. In fact, the application may + * stop issuing requests while the CPUs are busy serving other processes, + * then restart, then stop again for a while, and so on. In addition, if + * the disk achieves a low enough throughput with the request pattern + * issued by the application (e.g., because the request pattern is random + * and/or the device is slow), then the application may meet the above + * bandwidth requirement too. To prevent such a greedy application to be + * deemed as soft real-time, a further rule is used in the computation of + * soft_rt_next_start: soft_rt_next_start must be higher than the current + * time plus the maximum time for which the arrival of a request is waited + * for when a sync queue becomes idle, namely bfqd->bfq_slice_idle. + * This filters out greedy applications, as the latter issue instead their + * next request as soon as possible after the last one has been completed + * (in contrast, when a batch of requests is completed, a soft real-time + * application spends some time processing data). + * + * Unfortunately, the last filter may easily generate false positives if + * only bfqd->bfq_slice_idle is used as a reference time interval and one + * or both the following cases occur: + * 1) HZ is so low that the duration of a jiffy is comparable to or higher + * than bfqd->bfq_slice_idle. This happens, e.g., on slow devices with + * HZ=100. + * 2) jiffies, instead of increasing at a constant rate, may stop increasing + * for a while, then suddenly 'jump' by several units to recover the lost + * increments. This seems to happen, e.g., inside virtual machines. + * To address this issue, we do not use as a reference time interval just + * bfqd->bfq_slice_idle, but bfqd->bfq_slice_idle plus a few jiffies. In + * particular we add the minimum number of jiffies for which the filter + * seems to be quite precise also in embedded systems and KVM/QEMU virtual + * machines. + */ +static unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqd, bfqq, +"softrt_next_start: service_blkg %lu soft_rate %u sects/sec interval %u", + bfqq->service_from_backlogged, + bfqd->bfq_wr_max_softrt_rate, + jiffies_to_msecs(HZ * bfqq->service_from_backlogged / + bfqd->bfq_wr_max_softrt_rate)); + + return max(bfqq->last_idle_bklogged + + HZ * bfqq->service_from_backlogged / + bfqd->bfq_wr_max_softrt_rate, + jiffies + nsecs_to_jiffies(bfqq->bfqd->bfq_slice_idle) + 4); +} + +/** + * bfq_bfqq_expire - expire a queue. + * @bfqd: device owning the queue. + * @bfqq: the queue to expire. + * @compensate: if true, compensate for the time spent idling. + * @reason: the reason causing the expiration. + * + * If the process associated with bfqq does slow I/O (e.g., because it + * issues random requests), we charge bfqq with the time it has been + * in service instead of the service it has received (see + * bfq_bfqq_charge_time for details on how this goal is achieved). As + * a consequence, bfqq will typically get higher timestamps upon + * reactivation, and hence it will be rescheduled as if it had + * received more service than what it has actually received. In the + * end, bfqq receives less service in proportion to how slowly its + * associated process consumes its budgets (and hence how seriously it + * tends to lower the throughput). In addition, this time-charging + * strategy guarantees time fairness among slow processes. In + * contrast, if the process associated with bfqq is not slow, we + * charge bfqq exactly with the service it has received. + * + * Charging time to the first type of queues and the exact service to + * the other has the effect of using the WF2Q+ policy to schedule the + * former on a timeslice basis, without violating service domain + * guarantees among the latter. + */ +static void bfq_bfqq_expire(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + bool compensate, + enum bfqq_expiration reason) +{ + bool slow; + unsigned long delta = 0; + struct bfq_entity *entity = &bfqq->entity; + int ref; + + BUG_ON(bfqq != bfqd->in_service_queue); + + /* + * Check whether the process is slow (see bfq_bfqq_is_slow). + */ + slow = bfq_bfqq_is_slow(bfqd, bfqq, compensate, reason, &delta); + + /* + * Increase service_from_backlogged before next statement, + * because the possible next invocation of + * bfq_bfqq_charge_time would likely inflate + * entity->service. In contrast, service_from_backlogged must + * contain real service, to enable the soft real-time + * heuristic to correctly compute the bandwidth consumed by + * bfqq. + */ + bfqq->service_from_backlogged += entity->service; + + /* + * As above explained, charge slow (typically seeky) and + * timed-out queues with the time and not the service + * received, to favor sequential workloads. + * + * Processes doing I/O in the slower disk zones will tend to + * be slow(er) even if not seeky. Therefore, since the + * estimated peak rate is actually an average over the disk + * surface, these processes may timeout just for bad luck. To + * avoid punishing them, do not charge time to processes that + * succeeded in consuming at least 2/3 of their budget. This + * allows BFQ to preserve enough elasticity to still perform + * bandwidth, and not time, distribution with little unlucky + * or quasi-sequential processes. + */ + if (bfqq->wr_coeff == 1 && + (slow || + (reason == BFQ_BFQQ_BUDGET_TIMEOUT && + bfq_bfqq_budget_left(bfqq) >= entity->budget / 3))) + bfq_bfqq_charge_time(bfqd, bfqq, delta); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + if (reason == BFQ_BFQQ_TOO_IDLE && + entity->service <= 2 * entity->budget / 10) + bfq_clear_bfqq_IO_bound(bfqq); + + if (bfqd->low_latency && bfqq->wr_coeff == 1) + bfqq->last_wr_start_finish = jiffies; + + if (bfqd->low_latency && bfqd->bfq_wr_max_softrt_rate > 0 && + RB_EMPTY_ROOT(&bfqq->sort_list)) { + /* + * If we get here, and there are no outstanding + * requests, then the request pattern is isochronous + * (see the comments on the function + * bfq_bfqq_softrt_next_start()). Thus we can compute + * soft_rt_next_start. If, instead, the queue still + * has outstanding requests, then we have to wait for + * the completion of all the outstanding requests to + * discover whether the request pattern is actually + * isochronous. + */ + BUG_ON(bfqd->busy_queues < 1); + if (bfqq->dispatched == 0) { + bfqq->soft_rt_next_start = + bfq_bfqq_softrt_next_start(bfqd, bfqq); + bfq_log_bfqq(bfqd, bfqq, "new soft_rt_next %lu", + bfqq->soft_rt_next_start); + } else { + /* + * The application is still waiting for the + * completion of one or more requests: + * prevent it from possibly being incorrectly + * deemed as soft real-time by setting its + * soft_rt_next_start to infinity. In fact, + * without this assignment, the application + * would be incorrectly deemed as soft + * real-time if: + * 1) it issued a new request before the + * completion of all its in-flight + * requests, and + * 2) at that time, its soft_rt_next_start + * happened to be in the past. + */ + bfqq->soft_rt_next_start = + bfq_greatest_from_now(); + /* + * Schedule an update of soft_rt_next_start to when + * the task may be discovered to be isochronous. + */ + bfq_mark_bfqq_softrt_update(bfqq); + } + } + + bfq_log_bfqq(bfqd, bfqq, + "expire (%d, slow %d, num_disp %d, short_ttime %d, weight %d)", + reason, slow, bfqq->dispatched, + bfq_bfqq_has_short_ttime(bfqq), entity->weight); + + /* + * Increase, decrease or leave budget unchanged according to + * reason. + */ + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + __bfq_bfqq_recalc_budget(bfqd, bfqq, reason); + BUG_ON(bfqq->next_rq == NULL && + bfqq->entity.budget < bfqq->entity.service); + ref = bfqq->ref; + __bfq_bfqq_expire(bfqd, bfqq); + + BUG_ON(ref > 1 && + !bfq_bfqq_busy(bfqq) && reason == BFQ_BFQQ_BUDGET_EXHAUSTED && + !bfq_class_idle(bfqq)); + + /* mark bfqq as waiting a request only if a bic still points to it */ + if (ref > 1 && !bfq_bfqq_busy(bfqq) && + reason != BFQ_BFQQ_BUDGET_TIMEOUT && + reason != BFQ_BFQQ_BUDGET_EXHAUSTED) + bfq_mark_bfqq_non_blocking_wait_rq(bfqq); +} + +/* + * Budget timeout is not implemented through a dedicated timer, but + * just checked on request arrivals and completions, as well as on + * idle timer expirations. + */ +static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) +{ + return time_is_before_eq_jiffies(bfqq->budget_timeout); +} + +/* + * If we expire a queue that is actively waiting (i.e., with the + * device idled) for the arrival of a new request, then we may incur + * the timestamp misalignment problem described in the body of the + * function __bfq_activate_entity. Hence we return true only if this + * condition does not hold, or if the queue is slow enough to deserve + * only to be kicked off for preserving a high throughput. + */ +static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqq->bfqd, bfqq, + "may_budget_timeout: wait_request %d left %d timeout %d", + bfq_bfqq_wait_request(bfqq), + bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3, + bfq_bfqq_budget_timeout(bfqq)); + + return (!bfq_bfqq_wait_request(bfqq) || + bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3) + && + bfq_bfqq_budget_timeout(bfqq); +} + +/* + * For a queue that becomes empty, device idling is allowed only if + * this function returns true for that queue. As a consequence, since + * device idling plays a critical role for both throughput boosting + * and service guarantees, the return value of this function plays a + * critical role as well. + * + * In a nutshell, this function returns true only if idling is + * beneficial for throughput or, even if detrimental for throughput, + * idling is however necessary to preserve service guarantees (low + * latency, desired throughput distribution, ...). In particular, on + * NCQ-capable devices, this function tries to return false, so as to + * help keep the drives' internal queues full, whenever this helps the + * device boost the throughput without causing any service-guarantee + * issue. + * + * In more detail, the return value of this function is obtained by, + * first, computing a number of boolean variables that take into + * account throughput and service-guarantee issues, and, then, + * combining these variables in a logical expression. Most of the + * issues taken into account are not trivial. We discuss these issues + * while introducing the variables. + */ +static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq) +{ + struct bfq_data *bfqd = bfqq->bfqd; + bool rot_without_queueing = + !blk_queue_nonrot(bfqd->queue) && !bfqd->hw_tag, + bfqq_sequential_and_IO_bound, + idling_boosts_thr, idling_boosts_thr_without_issues, + idling_needed_for_service_guarantees, + asymmetric_scenario; + + if (bfqd->strict_guarantees) + return true; + + /* + * Idling is performed only if slice_idle > 0. In addition, we + * do not idle if + * (a) bfqq is async + * (b) bfqq is in the idle io prio class: in this case we do + * not idle because we want to minimize the bandwidth that + * queues in this class can steal to higher-priority queues + */ + if (bfqd->bfq_slice_idle == 0 || !bfq_bfqq_sync(bfqq) || + bfq_class_idle(bfqq)) + return false; + + bfqq_sequential_and_IO_bound = !BFQQ_SEEKY(bfqq) && + bfq_bfqq_IO_bound(bfqq) && bfq_bfqq_has_short_ttime(bfqq); + /* + * The next variable takes into account the cases where idling + * boosts the throughput. + * + * The value of the variable is computed considering, first, that + * idling is virtually always beneficial for the throughput if: + * (a) the device is not NCQ-capable and rotational, or + * (b) regardless of the presence of NCQ, the device is rotational and + * the request pattern for bfqq is I/O-bound and sequential, or + * (c) regardless of whether it is rotational, the device is + * not NCQ-capable and the request pattern for bfqq is + * I/O-bound and sequential. + * + * Secondly, and in contrast to the above item (b), idling an + * NCQ-capable flash-based device would not boost the + * throughput even with sequential I/O; rather it would lower + * the throughput in proportion to how fast the device + * is. Accordingly, the next variable is true if any of the + * above conditions (a), (b) or (c) is true, and, in + * particular, happens to be false if bfqd is an NCQ-capable + * flash-based device. + */ + idling_boosts_thr = rot_without_queueing || + ((!blk_queue_nonrot(bfqd->queue) || !bfqd->hw_tag) && + bfqq_sequential_and_IO_bound); + + /* + * The value of the next variable, + * idling_boosts_thr_without_issues, is equal to that of + * idling_boosts_thr, unless a special case holds. In this + * special case, described below, idling may cause problems to + * weight-raised queues. + * + * When the request pool is saturated (e.g., in the presence + * of write hogs), if the processes associated with + * non-weight-raised queues ask for requests at a lower rate, + * then processes associated with weight-raised queues have a + * higher probability to get a request from the pool + * immediately (or at least soon) when they need one. Thus + * they have a higher probability to actually get a fraction + * of the device throughput proportional to their high + * weight. This is especially true with NCQ-capable drives, + * which enqueue several requests in advance, and further + * reorder internally-queued requests. + * + * For this reason, we force to false the value of + * idling_boosts_thr_without_issues if there are weight-raised + * busy queues. In this case, and if bfqq is not weight-raised, + * this guarantees that the device is not idled for bfqq (if, + * instead, bfqq is weight-raised, then idling will be + * guaranteed by another variable, see below). Combined with + * the timestamping rules of BFQ (see [1] for details), this + * behavior causes bfqq, and hence any sync non-weight-raised + * queue, to get a lower number of requests served, and thus + * to ask for a lower number of requests from the request + * pool, before the busy weight-raised queues get served + * again. This often mitigates starvation problems in the + * presence of heavy write workloads and NCQ, thereby + * guaranteeing a higher application and system responsiveness + * in these hostile scenarios. + */ + idling_boosts_thr_without_issues = idling_boosts_thr && + bfqd->wr_busy_queues == 0; + + /* + * There is then a case where idling must be performed not + * for throughput concerns, but to preserve service + * guarantees. + * + * To introduce this case, we can note that allowing the drive + * to enqueue more than one request at a time, and hence + * delegating de facto final scheduling decisions to the + * drive's internal scheduler, entails loss of control on the + * actual request service order. In particular, the critical + * situation is when requests from different processes happen + * to be present, at the same time, in the internal queue(s) + * of the drive. In such a situation, the drive, by deciding + * the service order of the internally-queued requests, does + * determine also the actual throughput distribution among + * these processes. But the drive typically has no notion or + * concern about per-process throughput distribution, and + * makes its decisions only on a per-request basis. Therefore, + * the service distribution enforced by the drive's internal + * scheduler is likely to coincide with the desired + * device-throughput distribution only in a completely + * symmetric scenario where: + * (i) each of these processes must get the same throughput as + * the others; + * (ii) all these processes have the same I/O pattern + * (either sequential or random). + * In fact, in such a scenario, the drive will tend to treat + * the requests of each of these processes in about the same + * way as the requests of the others, and thus to provide + * each of these processes with about the same throughput + * (which is exactly the desired throughput distribution). In + * contrast, in any asymmetric scenario, device idling is + * certainly needed to guarantee that bfqq receives its + * assigned fraction of the device throughput (see [1] for + * details). + * + * We address this issue by controlling, actually, only the + * symmetry sub-condition (i), i.e., provided that + * sub-condition (i) holds, idling is not performed, + * regardless of whether sub-condition (ii) holds. In other + * words, only if sub-condition (i) holds, then idling is + * allowed, and the device tends to be prevented from queueing + * many requests, possibly of several processes. The reason + * for not controlling also sub-condition (ii) is that we + * exploit preemption to preserve guarantees in case of + * symmetric scenarios, even if (ii) does not hold, as + * explained in the next two paragraphs. + * + * Even if a queue, say Q, is expired when it remains idle, Q + * can still preempt the new in-service queue if the next + * request of Q arrives soon (see the comments on + * bfq_bfqq_update_budg_for_activation). If all queues and + * groups have the same weight, this form of preemption, + * combined with the hole-recovery heuristic described in the + * comments on function bfq_bfqq_update_budg_for_activation, + * are enough to preserve a correct bandwidth distribution in + * the mid term, even without idling. In fact, even if not + * idling allows the internal queues of the device to contain + * many requests, and thus to reorder requests, we can rather + * safely assume that the internal scheduler still preserves a + * minimum of mid-term fairness. The motivation for using + * preemption instead of idling is that, by not idling, + * service guarantees are preserved without minimally + * sacrificing throughput. In other words, both a high + * throughput and its desired distribution are obtained. + * + * More precisely, this preemption-based, idleless approach + * provides fairness in terms of IOPS, and not sectors per + * second. This can be seen with a simple example. Suppose + * that there are two queues with the same weight, but that + * the first queue receives requests of 8 sectors, while the + * second queue receives requests of 1024 sectors. In + * addition, suppose that each of the two queues contains at + * most one request at a time, which implies that each queue + * always remains idle after it is served. Finally, after + * remaining idle, each queue receives very quickly a new + * request. It follows that the two queues are served + * alternatively, preempting each other if needed. This + * implies that, although both queues have the same weight, + * the queue with large requests receives a service that is + * 1024/8 times as high as the service received by the other + * queue. + * + * On the other hand, device idling is performed, and thus + * pure sector-domain guarantees are provided, for the + * following queues, which are likely to need stronger + * throughput guarantees: weight-raised queues, and queues + * with a higher weight than other queues. When such queues + * are active, sub-condition (i) is false, which triggers + * device idling. + * + * According to the above considerations, the next variable is + * true (only) if sub-condition (i) holds. To compute the + * value of this variable, we not only use the return value of + * the function bfq_symmetric_scenario(), but also check + * whether bfqq is being weight-raised, because + * bfq_symmetric_scenario() does not take into account also + * weight-raised queues (see comments on + * bfq_weights_tree_add()). + * + * As a side note, it is worth considering that the above + * device-idling countermeasures may however fail in the + * following unlucky scenario: if idling is (correctly) + * disabled in a time period during which all symmetry + * sub-conditions hold, and hence the device is allowed to + * enqueue many requests, but at some later point in time some + * sub-condition stops to hold, then it may become impossible + * to let requests be served in the desired order until all + * the requests already queued in the device have been served. + */ + asymmetric_scenario = bfqq->wr_coeff > 1 || + !bfq_symmetric_scenario(bfqd); + + /* + * Finally, there is a case where maximizing throughput is the + * best choice even if it may cause unfairness toward + * bfqq. Such a case is when bfqq became active in a burst of + * queue activations. Queues that became active during a large + * burst benefit only from throughput, as discussed in the + * comments on bfq_handle_burst. Thus, if bfqq became active + * in a burst and not idling the device maximizes throughput, + * then the device must no be idled, because not idling the + * device provides bfqq and all other queues in the burst with + * maximum benefit. Combining this and the above case, we can + * now establish when idling is actually needed to preserve + * service guarantees. + */ + idling_needed_for_service_guarantees = + asymmetric_scenario && !bfq_bfqq_in_large_burst(bfqq); + + /* + * We have now all the components we need to compute the + * return value of the function, which is true only if idling + * either boosts the throughput (without issues), or is + * necessary to preserve service guarantees. + */ + bfq_log_bfqq(bfqd, bfqq, "may_idle: sync %d idling_boosts_thr %d", + bfq_bfqq_sync(bfqq), idling_boosts_thr); + + bfq_log_bfqq(bfqd, bfqq, + "may_idle: wr_busy %d boosts %d IO-bound %d guar %d", + bfqd->wr_busy_queues, + idling_boosts_thr_without_issues, + bfq_bfqq_IO_bound(bfqq), + idling_needed_for_service_guarantees); + + return idling_boosts_thr_without_issues || + idling_needed_for_service_guarantees; +} + +/* + * If the in-service queue is empty but the function bfq_bfqq_may_idle + * returns true, then: + * 1) the queue must remain in service and cannot be expired, and + * 2) the device must be idled to wait for the possible arrival of a new + * request for the queue. + * See the comments on the function bfq_bfqq_may_idle for the reasons + * why performing device idling is the best choice to boost the throughput + * and preserve service guarantees when bfq_bfqq_may_idle itself + * returns true. + */ +static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq) +{ + return RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_may_idle(bfqq); +} + +/* + * Select a queue for service. If we have a current queue in service, + * check whether to continue servicing it, or retrieve and set a new one. + */ +static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq; + struct request *next_rq; + enum bfqq_expiration reason = BFQ_BFQQ_BUDGET_TIMEOUT; + + bfqq = bfqd->in_service_queue; + if (!bfqq) + goto new_queue; + + bfq_log_bfqq(bfqd, bfqq, "select_queue: already in-service queue"); + + if (bfq_may_expire_for_budg_timeout(bfqq) && + !hrtimer_active(&bfqd->idle_slice_timer) && + !bfq_bfqq_must_idle(bfqq)) + goto expire; + +check_queue: + /* + * This loop is rarely executed more than once. Even when it + * happens, it is much more convenient to re-execute this loop + * than to return NULL and trigger a new dispatch to get a + * request served. + */ + next_rq = bfqq->next_rq; + /* + * If bfqq has requests queued and it has enough budget left to + * serve them, keep the queue, otherwise expire it. + */ + if (next_rq) { + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + + if (bfq_serv_to_charge(next_rq, bfqq) > + bfq_bfqq_budget_left(bfqq)) { + /* + * Expire the queue for budget exhaustion, + * which makes sure that the next budget is + * enough to serve the next request, even if + * it comes from the fifo expired path. + */ + reason = BFQ_BFQQ_BUDGET_EXHAUSTED; + goto expire; + } else { + /* + * The idle timer may be pending because we may + * not disable disk idling even when a new request + * arrives. + */ + if (bfq_bfqq_wait_request(bfqq)) { + BUG_ON(!hrtimer_active(&bfqd->idle_slice_timer)); + /* + * If we get here: 1) at least a new request + * has arrived but we have not disabled the + * timer because the request was too small, + * 2) then the block layer has unplugged + * the device, causing the dispatch to be + * invoked. + * + * Since the device is unplugged, now the + * requests are probably large enough to + * provide a reasonable throughput. + * So we disable idling. + */ + bfq_clear_bfqq_wait_request(bfqq); + hrtimer_try_to_cancel(&bfqd->idle_slice_timer); + bfqg_stats_update_idle_time(bfqq_group(bfqq)); + } + goto keep_queue; + } + } + + /* + * No requests pending. However, if the in-service queue is idling + * for a new request, or has requests waiting for a completion and + * may idle after their completion, then keep it anyway. + */ + if (hrtimer_active(&bfqd->idle_slice_timer) || + (bfqq->dispatched != 0 && bfq_bfqq_may_idle(bfqq))) { + bfqq = NULL; + goto keep_queue; + } + + reason = BFQ_BFQQ_NO_MORE_REQUESTS; +expire: + bfq_bfqq_expire(bfqd, bfqq, false, reason); +new_queue: + bfqq = bfq_set_in_service_queue(bfqd); + if (bfqq) { + bfq_log_bfqq(bfqd, bfqq, "select_queue: checking new queue"); + goto check_queue; + } +keep_queue: + if (bfqq) + bfq_log_bfqq(bfqd, bfqq, "select_queue: returned this queue"); + else + bfq_log(bfqd, "select_queue: no queue returned"); + + return bfqq; +} + +static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + struct bfq_entity *entity = &bfqq->entity; + + if (bfqq->wr_coeff > 1) { /* queue is being weight-raised */ + BUG_ON(bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + time_is_after_jiffies(bfqq->last_wr_start_finish)); + + bfq_log_bfqq(bfqd, bfqq, + "raising period dur %u/%u msec, old coeff %u, w %d(%d)", + jiffies_to_msecs(jiffies - bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time), + bfqq->wr_coeff, + bfqq->entity.weight, bfqq->entity.orig_weight); + + BUG_ON(bfqq != bfqd->in_service_queue && entity->weight != + entity->orig_weight * bfqq->wr_coeff); + if (entity->prio_changed) + bfq_log_bfqq(bfqd, bfqq, "WARN: pending prio change"); + + /* + * If the queue was activated in a burst, or too much + * time has elapsed from the beginning of this + * weight-raising period, then end weight raising. + */ + if (bfq_bfqq_in_large_burst(bfqq)) + bfq_bfqq_end_wr(bfqq); + else if (time_is_before_jiffies(bfqq->last_wr_start_finish + + bfqq->wr_cur_max_time)) { + if (bfqq->wr_cur_max_time != bfqd->bfq_wr_rt_max_time || + time_is_before_jiffies(bfqq->wr_start_at_switch_to_srt + + bfq_wr_duration(bfqd))) + bfq_bfqq_end_wr(bfqq); + else { + /* switch back to interactive wr */ + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + bfqq->last_wr_start_finish = + bfqq->wr_start_at_switch_to_srt; + BUG_ON(time_is_after_jiffies( + bfqq->last_wr_start_finish)); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqd, bfqq, + "back to interactive wr"); + } + } + } + /* + * To improve latency (for this or other queues), immediately + * update weight both if it must be raised and if it must be + * lowered. Since, entity may be on some active tree here, and + * might have a pending change of its ioprio class, invoke + * next function with the last parameter unset (see the + * comments on the function). + */ + if ((entity->weight > entity->orig_weight) != (bfqq->wr_coeff > 1)) + __bfq_entity_update_weight_prio(bfq_entity_service_tree(entity), + entity, false); +} + +/* + * Dispatch one request from bfqq, moving it to the request queue + * dispatch list. + */ +static int bfq_dispatch_request(struct bfq_data *bfqd, + struct bfq_queue *bfqq) +{ + int dispatched = 0; + struct request *rq = bfqq->next_rq; + unsigned long service_to_charge; + + BUG_ON(RB_EMPTY_ROOT(&bfqq->sort_list)); + BUG_ON(!rq); + service_to_charge = bfq_serv_to_charge(rq, bfqq); + + BUG_ON(service_to_charge > bfq_bfqq_budget_left(bfqq)); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + bfq_bfqq_served(bfqq, service_to_charge); + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + bfq_dispatch_insert(bfqd->queue, rq); + + /* + * If weight raising has to terminate for bfqq, then next + * function causes an immediate update of bfqq's weight, + * without waiting for next activation. As a consequence, on + * expiration, bfqq will be timestamped as if has never been + * weight-raised during this service slot, even if it has + * received part or even most of the service as a + * weight-raised queue. This inflates bfqq's timestamps, which + * is beneficial, as bfqq is then more willing to leave the + * device immediately to possible other weight-raised queues. + */ + bfq_update_wr_data(bfqd, bfqq); + + bfq_log_bfqq(bfqd, bfqq, + "dispatched %u sec req (%llu), budg left %d", + blk_rq_sectors(rq), + (unsigned long long) blk_rq_pos(rq), + bfq_bfqq_budget_left(bfqq)); + + dispatched++; + + if (!bfqd->in_service_bic) { + atomic_long_inc(&RQ_BIC(rq)->icq.ioc->refcount); + bfqd->in_service_bic = RQ_BIC(rq); + BUG_ON(!bfqd->in_service_bic); + } + + if (bfqd->busy_queues > 1 && bfq_class_idle(bfqq)) + goto expire; + + return dispatched; + +expire: + bfq_bfqq_expire(bfqd, bfqq, false, BFQ_BFQQ_BUDGET_EXHAUSTED); + return dispatched; +} + +static int __bfq_forced_dispatch_bfqq(struct bfq_queue *bfqq) +{ + int dispatched = 0; + + while (bfqq->next_rq) { + bfq_dispatch_insert(bfqq->bfqd->queue, bfqq->next_rq); + dispatched++; + } + + BUG_ON(!list_empty(&bfqq->fifo)); + return dispatched; +} + +/* + * Drain our current requests. + * Used for barriers and when switching io schedulers on-the-fly. + */ +static int bfq_forced_dispatch(struct bfq_data *bfqd) +{ + struct bfq_queue *bfqq, *n; + struct bfq_service_tree *st; + int dispatched = 0; + + bfqq = bfqd->in_service_queue; + if (bfqq) + __bfq_bfqq_expire(bfqd, bfqq); + + /* + * Loop through classes, and be careful to leave the scheduler + * in a consistent state, as feedback mechanisms and vtime + * updates cannot be disabled during the process. + */ + list_for_each_entry_safe(bfqq, n, &bfqd->active_list, bfqq_list) { + st = bfq_entity_service_tree(&bfqq->entity); + + dispatched += __bfq_forced_dispatch_bfqq(bfqq); + + bfqq->max_budget = bfq_max_budget(bfqd); + bfq_forget_idle(st); + } + + BUG_ON(bfqd->busy_queues != 0); + + return dispatched; +} + +static int bfq_dispatch_requests(struct request_queue *q, int force) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct bfq_queue *bfqq; + + bfq_log(bfqd, "dispatch requests: %d busy queues", bfqd->busy_queues); + + if (bfqd->busy_queues == 0) + return 0; + + if (unlikely(force)) + return bfq_forced_dispatch(bfqd); + + /* + * Force device to serve one request at a time if + * strict_guarantees is true. Forcing this service scheme is + * currently the ONLY way to guarantee that the request + * service order enforced by the scheduler is respected by a + * queueing device. Otherwise the device is free even to make + * some unlucky request wait for as long as the device + * wishes. + * + * Of course, serving one request at at time may cause loss of + * throughput. + */ + if (bfqd->strict_guarantees && bfqd->rq_in_driver > 0) + return 0; + + bfqq = bfq_select_queue(bfqd); + if (!bfqq) + return 0; + + BUG_ON(bfqq->entity.budget < bfqq->entity.service); + + BUG_ON(bfq_bfqq_wait_request(bfqq)); + + if (!bfq_dispatch_request(bfqd, bfqq)) + return 0; + + bfq_log_bfqq(bfqd, bfqq, "dispatched %s request", + bfq_bfqq_sync(bfqq) ? "sync" : "async"); + + BUG_ON(bfqq->next_rq == NULL && + bfqq->entity.budget < bfqq->entity.service); + return 1; +} + +/* + * Task holds one reference to the queue, dropped when task exits. Each rq + * in-flight on this queue also holds a reference, dropped when rq is freed. + * + * Queue lock must be held here. Recall not to use bfqq after calling + * this function on it. + */ +static void bfq_put_queue(struct bfq_queue *bfqq) +{ +#ifdef BFQ_GROUP_IOSCHED_ENABLED + struct bfq_group *bfqg = bfqq_group(bfqq); +#endif + + BUG_ON(bfqq->ref <= 0); + + bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p %d", bfqq, bfqq->ref); + bfqq->ref--; + if (bfqq->ref) + return; + + BUG_ON(rb_first(&bfqq->sort_list)); + BUG_ON(bfqq->allocated[READ] + bfqq->allocated[WRITE] != 0); + BUG_ON(bfqq->entity.tree); + BUG_ON(bfq_bfqq_busy(bfqq)); + + if (bfq_bfqq_sync(bfqq)) + /* + * The fact that this queue is being destroyed does not + * invalidate the fact that this queue may have been + * activated during the current burst. As a consequence, + * although the queue does not exist anymore, and hence + * needs to be removed from the burst list if there, + * the burst size has not to be decremented. + */ + hlist_del_init(&bfqq->burst_list_node); + + bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p freed", bfqq); + + kmem_cache_free(bfq_pool, bfqq); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + bfqg_put(bfqg); +#endif +} + +static void bfq_put_cooperator(struct bfq_queue *bfqq) +{ + struct bfq_queue *__bfqq, *next; + + /* + * If this queue was scheduled to merge with another queue, be + * sure to drop the reference taken on that queue (and others in + * the merge chain). See bfq_setup_merge and bfq_merge_bfqqs. + */ + __bfqq = bfqq->new_bfqq; + while (__bfqq) { + if (__bfqq == bfqq) + break; + next = __bfqq->new_bfqq; + bfq_put_queue(__bfqq); + __bfqq = next; + } +} + +static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + if (bfqq == bfqd->in_service_queue) { + __bfq_bfqq_expire(bfqd, bfqq); + bfq_schedule_dispatch(bfqd); + } + + bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, bfqq->ref); + + bfq_put_cooperator(bfqq); + + bfq_put_queue(bfqq); /* release process reference */ +} + +static void bfq_init_icq(struct io_cq *icq) +{ + icq_to_bic(icq)->ttime.last_end_request = ktime_get_ns() - (1ULL<<32); +} + +static void bfq_exit_icq(struct io_cq *icq) +{ + struct bfq_io_cq *bic = icq_to_bic(icq); + struct bfq_data *bfqd = bic_to_bfqd(bic); + + if (bic_to_bfqq(bic, false)) { + bfq_exit_bfqq(bfqd, bic_to_bfqq(bic, false)); + bic_set_bfqq(bic, NULL, false); + } + + if (bic_to_bfqq(bic, true)) { + /* + * If the bic is using a shared queue, put the reference + * taken on the io_context when the bic started using a + * shared bfq_queue. + */ + if (bfq_bfqq_coop(bic_to_bfqq(bic, true))) + put_io_context(icq->ioc); + bfq_exit_bfqq(bfqd, bic_to_bfqq(bic, true)); + bic_set_bfqq(bic, NULL, true); + } +} + +/* + * Update the entity prio values; note that the new values will not + * be used until the next (re)activation. + */ +static void bfq_set_next_ioprio_data(struct bfq_queue *bfqq, + struct bfq_io_cq *bic) +{ + struct task_struct *tsk = current; + int ioprio_class; + + ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); + switch (ioprio_class) { + default: + dev_err(bfqq->bfqd->queue->backing_dev_info->dev, + "bfq: bad prio class %d\n", ioprio_class); + case IOPRIO_CLASS_NONE: + /* + * No prio set, inherit CPU scheduling settings. + */ + bfqq->new_ioprio = task_nice_ioprio(tsk); + bfqq->new_ioprio_class = task_nice_ioclass(tsk); + break; + case IOPRIO_CLASS_RT: + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_RT; + break; + case IOPRIO_CLASS_BE: + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_BE; + break; + case IOPRIO_CLASS_IDLE: + bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE; + bfqq->new_ioprio = 7; + break; + } + + if (bfqq->new_ioprio >= IOPRIO_BE_NR) { + pr_crit("bfq_set_next_ioprio_data: new_ioprio %d\n", + bfqq->new_ioprio); + BUG(); + } + + bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio); + bfqq->entity.prio_changed = 1; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "set_next_ioprio_data: bic_class %d prio %d class %d", + ioprio_class, bfqq->new_ioprio, bfqq->new_ioprio_class); +} + +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) +{ + struct bfq_data *bfqd = bic_to_bfqd(bic); + struct bfq_queue *bfqq; + unsigned long uninitialized_var(flags); + int ioprio = bic->icq.ioc->ioprio; + + /* + * This condition may trigger on a newly created bic, be sure to + * drop the lock before returning. + */ + if (unlikely(!bfqd) || likely(bic->ioprio == ioprio)) + return; + + bic->ioprio = ioprio; + + bfqq = bic_to_bfqq(bic, false); + if (bfqq) { + /* release process reference on this queue */ + bfq_put_queue(bfqq); + bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic); + bic_set_bfqq(bic, bfqq, false); + bfq_log_bfqq(bfqd, bfqq, + "check_ioprio_change: bfqq %p %d", + bfqq, bfqq->ref); + } + + bfqq = bic_to_bfqq(bic, true); + if (bfqq) + bfq_set_next_ioprio_data(bfqq, bic); +} + +static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct bfq_io_cq *bic, pid_t pid, int is_sync) +{ + RB_CLEAR_NODE(&bfqq->entity.rb_node); + INIT_LIST_HEAD(&bfqq->fifo); + INIT_HLIST_NODE(&bfqq->burst_list_node); + BUG_ON(!hlist_unhashed(&bfqq->burst_list_node)); + + bfqq->ref = 0; + bfqq->bfqd = bfqd; + + if (bic) + bfq_set_next_ioprio_data(bfqq, bic); + + if (is_sync) { + /* + * No need to mark as has_short_ttime if in + * idle_class, because no device idling is performed + * for queues in idle class + */ + if (!bfq_class_idle(bfqq)) + /* tentatively mark as has_short_ttime */ + bfq_mark_bfqq_has_short_ttime(bfqq); + bfq_mark_bfqq_sync(bfqq); + bfq_mark_bfqq_just_created(bfqq); + } else + bfq_clear_bfqq_sync(bfqq); + bfq_mark_bfqq_IO_bound(bfqq); + + /* Tentative initial value to trade off between thr and lat */ + bfqq->max_budget = (2 * bfq_max_budget(bfqd)) / 3; + bfqq->pid = pid; + + bfqq->wr_coeff = 1; + bfqq->last_wr_start_finish = jiffies; + bfqq->wr_start_at_switch_to_srt = bfq_smallest_from_now(); + bfqq->budget_timeout = bfq_smallest_from_now(); + bfqq->split_time = bfq_smallest_from_now(); + + /* + * Set to the value for which bfqq will not be deemed as + * soft rt when it becomes backlogged. + */ + bfqq->soft_rt_next_start = bfq_greatest_from_now(); + + /* first request is almost certainly seeky */ + bfqq->seek_history = 1; +} + +static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd, + struct bfq_group *bfqg, + int ioprio_class, int ioprio) +{ + switch (ioprio_class) { + case IOPRIO_CLASS_RT: + return &bfqg->async_bfqq[0][ioprio]; + case IOPRIO_CLASS_NONE: + ioprio = IOPRIO_NORM; + /* fall through */ + case IOPRIO_CLASS_BE: + return &bfqg->async_bfqq[1][ioprio]; + case IOPRIO_CLASS_IDLE: + return &bfqg->async_idle_bfqq; + default: + BUG(); + } +} + +static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, + struct bio *bio, bool is_sync, + struct bfq_io_cq *bic) +{ + const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + const int ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); + struct bfq_queue **async_bfqq = NULL; + struct bfq_queue *bfqq; + struct bfq_group *bfqg; + + rcu_read_lock(); + + bfqg = bfq_find_set_group(bfqd, bio_blkcg(bio)); + if (!bfqg) { + bfqq = &bfqd->oom_bfqq; + goto out; + } + + if (!is_sync) { + async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class, + ioprio); + bfqq = *async_bfqq; + if (bfqq) + goto out; + } + + bfqq = kmem_cache_alloc_node(bfq_pool, + GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN, + bfqd->queue->node); + + if (bfqq) { + bfq_init_bfqq(bfqd, bfqq, bic, current->pid, + is_sync); + bfq_init_entity(&bfqq->entity, bfqg); + bfq_log_bfqq(bfqd, bfqq, "allocated"); + } else { + bfqq = &bfqd->oom_bfqq; + bfq_log_bfqq(bfqd, bfqq, "using oom bfqq"); + goto out; + } + + /* + * Pin the queue now that it's allocated, scheduler exit will + * prune it. + */ + if (async_bfqq) { + bfqq->ref++; /* + * Extra group reference, w.r.t. sync + * queue. This extra reference is removed + * only if bfqq->bfqg disappears, to + * guarantee that this queue is not freed + * until its group goes away. + */ + bfq_log_bfqq(bfqd, bfqq, "get_queue, bfqq not in async: %p, %d", + bfqq, bfqq->ref); + *async_bfqq = bfqq; + } + +out: + bfqq->ref++; /* get a process reference to this queue */ + bfq_log_bfqq(bfqd, bfqq, "get_queue, at end: %p, %d", bfqq, bfqq->ref); + rcu_read_unlock(); + return bfqq; +} + +static void bfq_update_io_thinktime(struct bfq_data *bfqd, + struct bfq_io_cq *bic) +{ + struct bfq_ttime *ttime = &bic->ttime; + u64 elapsed = ktime_get_ns() - bic->ttime.last_end_request; + + elapsed = min_t(u64, elapsed, 2 * bfqd->bfq_slice_idle); + + ttime->ttime_samples = (7*bic->ttime.ttime_samples + 256) / 8; + ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8); + ttime->ttime_mean = div64_ul(ttime->ttime_total + 128, + ttime->ttime_samples); +} + +static void +bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct request *rq) +{ + bfqq->seek_history <<= 1; + bfqq->seek_history |= + get_sdist(bfqq->last_request_pos, rq) > BFQQ_SEEK_THR && + (!blk_queue_nonrot(bfqd->queue) || + blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT); +} + +static void bfq_update_has_short_ttime(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + struct bfq_io_cq *bic) +{ + bool has_short_ttime = true; + + /* + * No need to update has_short_ttime if bfqq is async or in + * idle io prio class, or if bfq_slice_idle is zero, because + * no device idling is performed for bfqq in this case. + */ + if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq) || + bfqd->bfq_slice_idle == 0) + return; + + /* Idle window just restored, statistics are meaningless. */ + if (time_is_after_eq_jiffies(bfqq->split_time + + bfqd->bfq_wr_min_idle_time)) + return; + + /* Think time is infinite if no process is linked to + * bfqq. Otherwise check average think time to + * decide whether to mark as has_short_ttime + */ + if (atomic_read(&bic->icq.ioc->active_ref) == 0 || + (bfq_sample_valid(bic->ttime.ttime_samples) && + bic->ttime.ttime_mean > bfqd->bfq_slice_idle)) + has_short_ttime = false; + + bfq_log_bfqq(bfqd, bfqq, "update_has_short_ttime: has_short_ttime %d", + has_short_ttime); + + if (has_short_ttime) + bfq_mark_bfqq_has_short_ttime(bfqq); + else + bfq_clear_bfqq_has_short_ttime(bfqq); +} + +/* + * Called when a new fs request (rq) is added to bfqq. Check if there's + * something we should do about it. + */ +static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct request *rq) +{ + struct bfq_io_cq *bic = RQ_BIC(rq); + + if (rq->cmd_flags & REQ_META) + bfqq->meta_pending++; + + bfq_update_io_thinktime(bfqd, bic); + bfq_update_has_short_ttime(bfqd, bfqq, bic); + bfq_update_io_seektime(bfqd, bfqq, rq); + + bfq_log_bfqq(bfqd, bfqq, + "rq_enqueued: has_short_ttime=%d (seeky %d)", + bfq_bfqq_has_short_ttime(bfqq), BFQQ_SEEKY(bfqq)); + + bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); + + if (bfqq == bfqd->in_service_queue && bfq_bfqq_wait_request(bfqq)) { + bool small_req = bfqq->queued[rq_is_sync(rq)] == 1 && + blk_rq_sectors(rq) < 32; + bool budget_timeout = bfq_bfqq_budget_timeout(bfqq); + + /* + * There is just this request queued: if the request + * is small and the queue is not to be expired, then + * just exit. + * + * In this way, if the device is being idled to wait + * for a new request from the in-service queue, we + * avoid unplugging the device and committing the + * device to serve just a small request. On the + * contrary, we wait for the block layer to decide + * when to unplug the device: hopefully, new requests + * will be merged to this one quickly, then the device + * will be unplugged and larger requests will be + * dispatched. + */ + if (small_req && !budget_timeout) + return; + + /* + * A large enough request arrived, or the queue is to + * be expired: in both cases disk idling is to be + * stopped, so clear wait_request flag and reset + * timer. + */ + bfq_clear_bfqq_wait_request(bfqq); + hrtimer_try_to_cancel(&bfqd->idle_slice_timer); + bfqg_stats_update_idle_time(bfqq_group(bfqq)); + + /* + * The queue is not empty, because a new request just + * arrived. Hence we can safely expire the queue, in + * case of budget timeout, without risking that the + * timestamps of the queue are not updated correctly. + * See [1] for more details. + */ + if (budget_timeout) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); + + /* + * Let the request rip immediately, or let a new queue be + * selected if bfqq has just been expired. + */ + __blk_run_queue(bfqd->queue); + } +} + +static void bfq_insert_request(struct request_queue *q, struct request *rq) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct bfq_queue *bfqq = RQ_BFQQ(rq), *new_bfqq; + + assert_spin_locked(bfqd->queue->queue_lock); + + /* + * An unplug may trigger a requeue of a request from the device + * driver: make sure we are in process context while trying to + * merge two bfq_queues. + */ + if (!in_interrupt()) { + new_bfqq = bfq_setup_cooperator(bfqd, bfqq, rq, true); + if (new_bfqq) { + if (bic_to_bfqq(RQ_BIC(rq), 1) != bfqq) + new_bfqq = bic_to_bfqq(RQ_BIC(rq), 1); + /* + * Release the request's reference to the old bfqq + * and make sure one is taken to the shared queue. + */ + new_bfqq->allocated[rq_data_dir(rq)]++; + bfqq->allocated[rq_data_dir(rq)]--; + new_bfqq->ref++; + bfq_clear_bfqq_just_created(bfqq); + if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) + bfq_merge_bfqqs(bfqd, RQ_BIC(rq), + bfqq, new_bfqq); + /* + * rq is about to be enqueued into new_bfqq, + * release rq reference on bfqq + */ + bfq_put_queue(bfqq); + rq->elv.priv[1] = new_bfqq; + bfqq = new_bfqq; + } + } + + bfq_add_request(rq); + + rq->fifo_time = ktime_get_ns() + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; + list_add_tail(&rq->queuelist, &bfqq->fifo); + + bfq_rq_enqueued(bfqd, bfqq, rq); +} + +static void bfq_update_hw_tag(struct bfq_data *bfqd) +{ + bfqd->max_rq_in_driver = max_t(int, bfqd->max_rq_in_driver, + bfqd->rq_in_driver); + + if (bfqd->hw_tag == 1) + return; + + /* + * This sample is valid if the number of outstanding requests + * is large enough to allow a queueing behavior. Note that the + * sum is not exact, as it's not taking into account deactivated + * requests. + */ + if (bfqd->rq_in_driver + bfqd->queued < BFQ_HW_QUEUE_THRESHOLD) + return; + + if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES) + return; + + bfqd->hw_tag = bfqd->max_rq_in_driver > BFQ_HW_QUEUE_THRESHOLD; + bfqd->max_rq_in_driver = 0; + bfqd->hw_tag_samples = 0; +} + +static void bfq_completed_request(struct request_queue *q, struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + struct bfq_data *bfqd = bfqq->bfqd; + u64 now_ns; + u32 delta_us; + + bfq_log_bfqq(bfqd, bfqq, "completed one req with %u sects left", + blk_rq_sectors(rq)); + + assert_spin_locked(bfqd->queue->queue_lock); + bfq_update_hw_tag(bfqd); + + BUG_ON(!bfqd->rq_in_driver); + BUG_ON(!bfqq->dispatched); + bfqd->rq_in_driver--; + bfqq->dispatched--; + bfqg_stats_update_completion(bfqq_group(bfqq), + rq_start_time_ns(rq), + rq_io_start_time_ns(rq), + rq->cmd_flags); + + if (!bfqq->dispatched && !bfq_bfqq_busy(bfqq)) { + BUG_ON(!RB_EMPTY_ROOT(&bfqq->sort_list)); + /* + * Set budget_timeout (which we overload to store the + * time at which the queue remains with no backlog and + * no outstanding request; used by the weight-raising + * mechanism). + */ + bfqq->budget_timeout = jiffies; + + bfq_weights_tree_remove(bfqd, &bfqq->entity, + &bfqd->queue_weights_tree); + } + + now_ns = ktime_get_ns(); + + RQ_BIC(rq)->ttime.last_end_request = now_ns; + + /* + * Using us instead of ns, to get a reasonable precision in + * computing rate in next check. + */ + delta_us = div_u64(now_ns - bfqd->last_completion, NSEC_PER_USEC); + + bfq_log(bfqd, "rq_completed: delta %uus/%luus max_size %u rate %llu/%llu", + delta_us, BFQ_MIN_TT/NSEC_PER_USEC, bfqd->last_rq_max_size, + (USEC_PER_SEC* + (u64)((bfqd->last_rq_max_size<>BFQ_RATE_SHIFT, + (USEC_PER_SEC*(u64)(1UL<<(BFQ_RATE_SHIFT-10)))>>BFQ_RATE_SHIFT); + + /* + * If the request took rather long to complete, and, according + * to the maximum request size recorded, this completion latency + * implies that the request was certainly served at a very low + * rate (less than 1M sectors/sec), then the whole observation + * interval that lasts up to this time instant cannot be a + * valid time interval for computing a new peak rate. Invoke + * bfq_update_rate_reset to have the following three steps + * taken: + * - close the observation interval at the last (previous) + * request dispatch or completion + * - compute rate, if possible, for that observation interval + * - reset to zero samples, which will trigger a proper + * re-initialization of the observation interval on next + * dispatch + */ + if (delta_us > BFQ_MIN_TT/NSEC_PER_USEC && + (bfqd->last_rq_max_size<last_completion = now_ns; + + /* + * If we are waiting to discover whether the request pattern + * of the task associated with the queue is actually + * isochronous, and both requisites for this condition to hold + * are now satisfied, then compute soft_rt_next_start (see the + * comments on the function bfq_bfqq_softrt_next_start()). We + * schedule this delayed check when bfqq expires, if it still + * has in-flight requests. + */ + if (bfq_bfqq_softrt_update(bfqq) && bfqq->dispatched == 0 && + RB_EMPTY_ROOT(&bfqq->sort_list)) + bfqq->soft_rt_next_start = + bfq_bfqq_softrt_next_start(bfqd, bfqq); + + /* + * If this is the in-service queue, check if it needs to be expired, + * or if we want to idle in case it has no pending requests. + */ + if (bfqd->in_service_queue == bfqq) { + if (bfqq->dispatched == 0 && bfq_bfqq_must_idle(bfqq)) { + bfq_arm_slice_timer(bfqd); + goto out; + } else if (bfq_may_expire_for_budg_timeout(bfqq)) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); + else if (RB_EMPTY_ROOT(&bfqq->sort_list) && + (bfqq->dispatched == 0 || + !bfq_bfqq_may_idle(bfqq))) + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_NO_MORE_REQUESTS); + } + + if (!bfqd->rq_in_driver) + bfq_schedule_dispatch(bfqd); + +out: + return; +} + +static int __bfq_may_queue(struct bfq_queue *bfqq) +{ + if (bfq_bfqq_wait_request(bfqq) && bfq_bfqq_must_alloc(bfqq)) { + bfq_clear_bfqq_must_alloc(bfqq); + return ELV_MQUEUE_MUST; + } + + return ELV_MQUEUE_MAY; +} + +static int bfq_may_queue(struct request_queue *q, unsigned int op) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct task_struct *tsk = current; + struct bfq_io_cq *bic; + struct bfq_queue *bfqq; + + /* + * Don't force setup of a queue from here, as a call to may_queue + * does not necessarily imply that a request actually will be + * queued. So just lookup a possibly existing queue, or return + * 'may queue' if that fails. + */ + bic = bfq_bic_lookup(bfqd, tsk->io_context); + if (!bic) + return ELV_MQUEUE_MAY; + + bfqq = bic_to_bfqq(bic, op_is_sync(op)); + if (bfqq) + return __bfq_may_queue(bfqq); + + return ELV_MQUEUE_MAY; +} + +/* + * Queue lock held here. + */ +static void bfq_put_request(struct request *rq) +{ + struct bfq_queue *bfqq = RQ_BFQQ(rq); + + if (bfqq) { + const int rw = rq_data_dir(rq); + + BUG_ON(!bfqq->allocated[rw]); + bfqq->allocated[rw]--; + + rq->elv.priv[0] = NULL; + rq->elv.priv[1] = NULL; + + bfq_log_bfqq(bfqq->bfqd, bfqq, "put_request %p, %d", + bfqq, bfqq->ref); + bfq_put_queue(bfqq); + } +} + +/* + * Returns NULL if a new bfqq should be allocated, or the old bfqq if this + * was the last process referring to that bfqq. + */ +static struct bfq_queue * +bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq) +{ + bfq_log_bfqq(bfqq->bfqd, bfqq, "splitting queue"); + + put_io_context(bic->icq.ioc); + + if (bfqq_process_refs(bfqq) == 1) { + bfqq->pid = current->pid; + bfq_clear_bfqq_coop(bfqq); + bfq_clear_bfqq_split_coop(bfqq); + return bfqq; + } + + bic_set_bfqq(bic, NULL, 1); + + bfq_put_cooperator(bfqq); + + bfq_put_queue(bfqq); + return NULL; +} + +/* + * Allocate bfq data structures associated with this request. + */ +static int bfq_set_request(struct request_queue *q, struct request *rq, + struct bio *bio, gfp_t gfp_mask) +{ + struct bfq_data *bfqd = q->elevator->elevator_data; + struct bfq_io_cq *bic = icq_to_bic(rq->elv.icq); + const int rw = rq_data_dir(rq); + const int is_sync = rq_is_sync(rq); + struct bfq_queue *bfqq; + unsigned long flags; + bool bfqq_already_existing = false, split = false; + + spin_lock_irqsave(q->queue_lock, flags); + + if (!bic) + goto queue_fail; + + bfq_check_ioprio_change(bic, bio); + + bfq_bic_update_cgroup(bic, bio); + +new_queue: + bfqq = bic_to_bfqq(bic, is_sync); + if (!bfqq || bfqq == &bfqd->oom_bfqq) { + if (bfqq) + bfq_put_queue(bfqq); + bfqq = bfq_get_queue(bfqd, bio, is_sync, bic); + BUG_ON(!hlist_unhashed(&bfqq->burst_list_node)); + + bic_set_bfqq(bic, bfqq, is_sync); + if (split && is_sync) { + bfq_log_bfqq(bfqd, bfqq, + "set_request: was_in_list %d " + "was_in_large_burst %d " + "large burst in progress %d", + bic->was_in_burst_list, + bic->saved_in_large_burst, + bfqd->large_burst); + + if ((bic->was_in_burst_list && bfqd->large_burst) || + bic->saved_in_large_burst) { + bfq_log_bfqq(bfqd, bfqq, + "set_request: marking in " + "large burst"); + bfq_mark_bfqq_in_large_burst(bfqq); + } else { + bfq_log_bfqq(bfqd, bfqq, + "set_request: clearing in " + "large burst"); + bfq_clear_bfqq_in_large_burst(bfqq); + if (bic->was_in_burst_list) + hlist_add_head(&bfqq->burst_list_node, + &bfqd->burst_list); + } + bfqq->split_time = jiffies; + } + } else { + /* If the queue was seeky for too long, break it apart. */ + if (bfq_bfqq_coop(bfqq) && bfq_bfqq_split_coop(bfqq)) { + bfq_log_bfqq(bfqd, bfqq, "breaking apart bfqq"); + + /* Update bic before losing reference to bfqq */ + if (bfq_bfqq_in_large_burst(bfqq)) + bic->saved_in_large_burst = true; + + bfqq = bfq_split_bfqq(bic, bfqq); + split = true; + if (!bfqq) + goto new_queue; + else + bfqq_already_existing = true; + } + } + + bfqq->allocated[rw]++; + bfqq->ref++; + bfq_log_bfqq(bfqd, bfqq, "set_request: bfqq %p, %d", bfqq, bfqq->ref); + + rq->elv.priv[0] = bic; + rq->elv.priv[1] = bfqq; + + /* + * If a bfq_queue has only one process reference, it is owned + * by only one bfq_io_cq: we can set the bic field of the + * bfq_queue to the address of that structure. Also, if the + * queue has just been split, mark a flag so that the + * information is available to the other scheduler hooks. + */ + if (likely(bfqq != &bfqd->oom_bfqq) && bfqq_process_refs(bfqq) == 1) { + bfqq->bic = bic; + if (split) { + /* + * If the queue has just been split from a shared + * queue, restore the idle window and the possible + * weight raising period. + */ + bfq_bfqq_resume_state(bfqq, bfqd, bic, + bfqq_already_existing); + } + } + + if (unlikely(bfq_bfqq_just_created(bfqq))) + bfq_handle_burst(bfqd, bfqq); + + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; + +queue_fail: + bfq_schedule_dispatch(bfqd); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 1; +} + +static void bfq_kick_queue(struct work_struct *work) +{ + struct bfq_data *bfqd = + container_of(work, struct bfq_data, unplug_work); + struct request_queue *q = bfqd->queue; + + spin_lock_irq(q->queue_lock); + __blk_run_queue(q); + spin_unlock_irq(q->queue_lock); +} + +/* + * Handler of the expiration of the timer running if the in-service queue + * is idling inside its time slice. + */ +static enum hrtimer_restart bfq_idle_slice_timer(struct hrtimer *timer) +{ + struct bfq_data *bfqd = container_of(timer, struct bfq_data, + idle_slice_timer); + struct bfq_queue *bfqq; + unsigned long flags; + enum bfqq_expiration reason; + + spin_lock_irqsave(bfqd->queue->queue_lock, flags); + + bfqq = bfqd->in_service_queue; + /* + * Theoretical race here: the in-service queue can be NULL or + * different from the queue that was idling if the timer handler + * spins on the queue_lock and a new request arrives for the + * current queue and there is a full dispatch cycle that changes + * the in-service queue. This can hardly happen, but in the worst + * case we just expire a queue too early. + */ + if (bfqq) { + bfq_log_bfqq(bfqd, bfqq, "slice_timer expired"); + bfq_clear_bfqq_wait_request(bfqq); + + if (bfq_bfqq_budget_timeout(bfqq)) + /* + * Also here the queue can be safely expired + * for budget timeout without wasting + * guarantees + */ + reason = BFQ_BFQQ_BUDGET_TIMEOUT; + else if (bfqq->queued[0] == 0 && bfqq->queued[1] == 0) + /* + * The queue may not be empty upon timer expiration, + * because we may not disable the timer when the + * first request of the in-service queue arrives + * during disk idling. + */ + reason = BFQ_BFQQ_TOO_IDLE; + else + goto schedule_dispatch; + + bfq_bfqq_expire(bfqd, bfqq, true, reason); + } + +schedule_dispatch: + bfq_schedule_dispatch(bfqd); + + spin_unlock_irqrestore(bfqd->queue->queue_lock, flags); + return HRTIMER_NORESTART; +} + +static void bfq_shutdown_timer_wq(struct bfq_data *bfqd) +{ + hrtimer_cancel(&bfqd->idle_slice_timer); + cancel_work_sync(&bfqd->unplug_work); +} + +static void __bfq_put_async_bfqq(struct bfq_data *bfqd, + struct bfq_queue **bfqq_ptr) +{ + struct bfq_group *root_group = bfqd->root_group; + struct bfq_queue *bfqq = *bfqq_ptr; + + bfq_log(bfqd, "put_async_bfqq: %p", bfqq); + if (bfqq) { + bfq_bfqq_move(bfqd, bfqq, root_group); + bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d", + bfqq, bfqq->ref); + bfq_put_queue(bfqq); + *bfqq_ptr = NULL; + } +} + +/* + * Release all the bfqg references to its async queues. If we are + * deallocating the group these queues may still contain requests, so + * we reparent them to the root cgroup (i.e., the only one that will + * exist for sure until all the requests on a device are gone). + */ +static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) +{ + int i, j; + + for (i = 0; i < 2; i++) + for (j = 0; j < IOPRIO_BE_NR; j++) + __bfq_put_async_bfqq(bfqd, &bfqg->async_bfqq[i][j]); + + __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq); +} + +static void bfq_exit_queue(struct elevator_queue *e) +{ + struct bfq_data *bfqd = e->elevator_data; + struct request_queue *q = bfqd->queue; + struct bfq_queue *bfqq, *n; + + bfq_shutdown_timer_wq(bfqd); + + spin_lock_irq(q->queue_lock); + + BUG_ON(bfqd->in_service_queue); + list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list) + bfq_deactivate_bfqq(bfqd, bfqq, false, false); + + spin_unlock_irq(q->queue_lock); + + bfq_shutdown_timer_wq(bfqd); + + BUG_ON(hrtimer_active(&bfqd->idle_slice_timer)); + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_deactivate_policy(q, &blkcg_policy_bfq); +#else + bfq_put_async_queues(bfqd, bfqd->root_group); + kfree(bfqd->root_group); +#endif + + kfree(bfqd); +} + +static void bfq_init_root_group(struct bfq_group *root_group, + struct bfq_data *bfqd) +{ + int i; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + root_group->entity.parent = NULL; + root_group->my_entity = NULL; + root_group->bfqd = bfqd; +#endif + root_group->rq_pos_tree = RB_ROOT; + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) + root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; + root_group->sched_data.bfq_class_idle_last_service = jiffies; +} + +static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) +{ + struct bfq_data *bfqd; + struct elevator_queue *eq; + + eq = elevator_alloc(q, e); + if (!eq) + return -ENOMEM; + + bfqd = kzalloc_node(sizeof(*bfqd), GFP_KERNEL, q->node); + if (!bfqd) { + kobject_put(&eq->kobj); + return -ENOMEM; + } + eq->elevator_data = bfqd; + + /* + * Our fallback bfqq if bfq_find_alloc_queue() runs into OOM issues. + * Grab a permanent reference to it, so that the normal code flow + * will not attempt to free it. + */ + bfq_init_bfqq(bfqd, &bfqd->oom_bfqq, NULL, 1, 0); + bfqd->oom_bfqq.ref++; + bfqd->oom_bfqq.new_ioprio = BFQ_DEFAULT_QUEUE_IOPRIO; + bfqd->oom_bfqq.new_ioprio_class = IOPRIO_CLASS_BE; + bfqd->oom_bfqq.entity.new_weight = + bfq_ioprio_to_weight(bfqd->oom_bfqq.new_ioprio); + + /* oom_bfqq does not participate to bursts */ + bfq_clear_bfqq_just_created(&bfqd->oom_bfqq); + /* + * Trigger weight initialization, according to ioprio, at the + * oom_bfqq's first activation. The oom_bfqq's ioprio and ioprio + * class won't be changed any more. + */ + bfqd->oom_bfqq.entity.prio_changed = 1; + + bfqd->queue = q; + + spin_lock_irq(q->queue_lock); + q->elevator = eq; + spin_unlock_irq(q->queue_lock); + + bfqd->root_group = bfq_create_group_hierarchy(bfqd, q->node); + if (!bfqd->root_group) + goto out_free; + bfq_init_root_group(bfqd->root_group, bfqd); + bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group); + + hrtimer_init(&bfqd->idle_slice_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + bfqd->idle_slice_timer.function = bfq_idle_slice_timer; + + bfqd->queue_weights_tree = RB_ROOT; + bfqd->group_weights_tree = RB_ROOT; + + INIT_WORK(&bfqd->unplug_work, bfq_kick_queue); + + INIT_LIST_HEAD(&bfqd->active_list); + INIT_LIST_HEAD(&bfqd->idle_list); + INIT_HLIST_HEAD(&bfqd->burst_list); + + bfqd->hw_tag = -1; + + bfqd->bfq_max_budget = bfq_default_max_budget; + + bfqd->bfq_fifo_expire[0] = bfq_fifo_expire[0]; + bfqd->bfq_fifo_expire[1] = bfq_fifo_expire[1]; + bfqd->bfq_back_max = bfq_back_max; + bfqd->bfq_back_penalty = bfq_back_penalty; + bfqd->bfq_slice_idle = bfq_slice_idle; + bfqd->bfq_timeout = bfq_timeout; + + bfqd->bfq_requests_within_timer = 120; + + bfqd->bfq_large_burst_thresh = 8; + bfqd->bfq_burst_interval = msecs_to_jiffies(180); + + bfqd->low_latency = true; + + /* + * Trade-off between responsiveness and fairness. + */ + bfqd->bfq_wr_coeff = 30; + bfqd->bfq_wr_rt_max_time = msecs_to_jiffies(300); + bfqd->bfq_wr_max_time = 0; + bfqd->bfq_wr_min_idle_time = msecs_to_jiffies(2000); + bfqd->bfq_wr_min_inter_arr_async = msecs_to_jiffies(500); + bfqd->bfq_wr_max_softrt_rate = 7000; /* + * Approximate rate required + * to playback or record a + * high-definition compressed + * video. + */ + bfqd->wr_busy_queues = 0; + + /* + * Begin by assuming, optimistically, that the device is a + * high-speed one, and that its peak rate is equal to 2/3 of + * the highest reference rate. + */ + bfqd->RT_prod = R_fast[blk_queue_nonrot(bfqd->queue)] * + T_fast[blk_queue_nonrot(bfqd->queue)]; + bfqd->peak_rate = R_fast[blk_queue_nonrot(bfqd->queue)] * 2 / 3; + bfqd->device_speed = BFQ_BFQD_FAST; + + return 0; + +out_free: + kfree(bfqd); + kobject_put(&eq->kobj); + return -ENOMEM; +} + +static void bfq_slab_kill(void) +{ + kmem_cache_destroy(bfq_pool); +} + +static int __init bfq_slab_setup(void) +{ + bfq_pool = KMEM_CACHE(bfq_queue, 0); + if (!bfq_pool) + return -ENOMEM; + return 0; +} + +static ssize_t bfq_var_show(unsigned int var, char *page) +{ + return sprintf(page, "%u\n", var); +} + +static ssize_t bfq_var_store(unsigned long *var, const char *page, + size_t count) +{ + unsigned long new_val; + int ret = kstrtoul(page, 10, &new_val); + + if (ret == 0) + *var = new_val; + + return count; +} + +static ssize_t bfq_wr_max_time_show(struct elevator_queue *e, char *page) +{ + struct bfq_data *bfqd = e->elevator_data; + + return sprintf(page, "%d\n", bfqd->bfq_wr_max_time > 0 ? + jiffies_to_msecs(bfqd->bfq_wr_max_time) : + jiffies_to_msecs(bfq_wr_duration(bfqd))); +} + +static ssize_t bfq_weights_show(struct elevator_queue *e, char *page) +{ + struct bfq_queue *bfqq; + struct bfq_data *bfqd = e->elevator_data; + ssize_t num_char = 0; + + num_char += sprintf(page + num_char, "Tot reqs queued %d\n\n", + bfqd->queued); + + spin_lock_irq(bfqd->queue->queue_lock); + + num_char += sprintf(page + num_char, "Active:\n"); + list_for_each_entry(bfqq, &bfqd->active_list, bfqq_list) { + num_char += sprintf(page + num_char, + "pid%d: weight %hu, nr_queued %d %d, ", + bfqq->pid, + bfqq->entity.weight, + bfqq->queued[0], + bfqq->queued[1]); + num_char += sprintf(page + num_char, + "dur %d/%u\n", + jiffies_to_msecs( + jiffies - + bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + num_char += sprintf(page + num_char, "Idle:\n"); + list_for_each_entry(bfqq, &bfqd->idle_list, bfqq_list) { + num_char += sprintf(page + num_char, + "pid%d: weight %hu, dur %d/%u\n", + bfqq->pid, + bfqq->entity.weight, + jiffies_to_msecs(jiffies - + bfqq->last_wr_start_finish), + jiffies_to_msecs(bfqq->wr_cur_max_time)); + } + + spin_unlock_irq(bfqd->queue->queue_lock); + + return num_char; +} + +#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ +static ssize_t __FUNC(struct elevator_queue *e, char *page) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + u64 __data = __VAR; \ + if (__CONV == 1) \ + __data = jiffies_to_msecs(__data); \ + else if (__CONV == 2) \ + __data = div_u64(__data, NSEC_PER_MSEC); \ + return bfq_var_show(__data, (page)); \ +} +SHOW_FUNCTION(bfq_fifo_expire_sync_show, bfqd->bfq_fifo_expire[1], 2); +SHOW_FUNCTION(bfq_fifo_expire_async_show, bfqd->bfq_fifo_expire[0], 2); +SHOW_FUNCTION(bfq_back_seek_max_show, bfqd->bfq_back_max, 0); +SHOW_FUNCTION(bfq_back_seek_penalty_show, bfqd->bfq_back_penalty, 0); +SHOW_FUNCTION(bfq_slice_idle_show, bfqd->bfq_slice_idle, 2); +SHOW_FUNCTION(bfq_max_budget_show, bfqd->bfq_user_max_budget, 0); +SHOW_FUNCTION(bfq_timeout_sync_show, bfqd->bfq_timeout, 1); +SHOW_FUNCTION(bfq_strict_guarantees_show, bfqd->strict_guarantees, 0); +SHOW_FUNCTION(bfq_low_latency_show, bfqd->low_latency, 0); +SHOW_FUNCTION(bfq_wr_coeff_show, bfqd->bfq_wr_coeff, 0); +SHOW_FUNCTION(bfq_wr_rt_max_time_show, bfqd->bfq_wr_rt_max_time, 1); +SHOW_FUNCTION(bfq_wr_min_idle_time_show, bfqd->bfq_wr_min_idle_time, 1); +SHOW_FUNCTION(bfq_wr_min_inter_arr_async_show, bfqd->bfq_wr_min_inter_arr_async, + 1); +SHOW_FUNCTION(bfq_wr_max_softrt_rate_show, bfqd->bfq_wr_max_softrt_rate, 0); +#undef SHOW_FUNCTION + +#define USEC_SHOW_FUNCTION(__FUNC, __VAR) \ +static ssize_t __FUNC(struct elevator_queue *e, char *page) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + u64 __data = __VAR; \ + __data = div_u64(__data, NSEC_PER_USEC); \ + return bfq_var_show(__data, (page)); \ +} +USEC_SHOW_FUNCTION(bfq_slice_idle_us_show, bfqd->bfq_slice_idle); +#undef USEC_SHOW_FUNCTION + +#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ +static ssize_t \ +__FUNC(struct elevator_queue *e, const char *page, size_t count) \ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + unsigned long uninitialized_var(__data); \ + int ret = bfq_var_store(&__data, (page), count); \ + if (__data < (MIN)) \ + __data = (MIN); \ + else if (__data > (MAX)) \ + __data = (MAX); \ + if (__CONV == 1) \ + *(__PTR) = msecs_to_jiffies(__data); \ + else if (__CONV == 2) \ + *(__PTR) = (u64)__data * NSEC_PER_MSEC; \ + else \ + *(__PTR) = __data; \ + return ret; \ +} +STORE_FUNCTION(bfq_fifo_expire_sync_store, &bfqd->bfq_fifo_expire[1], 1, + INT_MAX, 2); +STORE_FUNCTION(bfq_fifo_expire_async_store, &bfqd->bfq_fifo_expire[0], 1, + INT_MAX, 2); +STORE_FUNCTION(bfq_back_seek_max_store, &bfqd->bfq_back_max, 0, INT_MAX, 0); +STORE_FUNCTION(bfq_back_seek_penalty_store, &bfqd->bfq_back_penalty, 1, + INT_MAX, 0); +STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 2); +STORE_FUNCTION(bfq_wr_coeff_store, &bfqd->bfq_wr_coeff, 1, INT_MAX, 0); +STORE_FUNCTION(bfq_wr_max_time_store, &bfqd->bfq_wr_max_time, 0, INT_MAX, 1); +STORE_FUNCTION(bfq_wr_rt_max_time_store, &bfqd->bfq_wr_rt_max_time, 0, INT_MAX, + 1); +STORE_FUNCTION(bfq_wr_min_idle_time_store, &bfqd->bfq_wr_min_idle_time, 0, + INT_MAX, 1); +STORE_FUNCTION(bfq_wr_min_inter_arr_async_store, + &bfqd->bfq_wr_min_inter_arr_async, 0, INT_MAX, 1); +STORE_FUNCTION(bfq_wr_max_softrt_rate_store, &bfqd->bfq_wr_max_softrt_rate, 0, + INT_MAX, 0); +#undef STORE_FUNCTION + +#define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \ +static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)\ +{ \ + struct bfq_data *bfqd = e->elevator_data; \ + unsigned long uninitialized_var(__data); \ + int ret = bfq_var_store(&__data, (page), count); \ + if (__data < (MIN)) \ + __data = (MIN); \ + else if (__data > (MAX)) \ + __data = (MAX); \ + *(__PTR) = (u64)__data * NSEC_PER_USEC; \ + return ret; \ +} +USEC_STORE_FUNCTION(bfq_slice_idle_us_store, &bfqd->bfq_slice_idle, 0, + UINT_MAX); +#undef USEC_STORE_FUNCTION + +/* do nothing for the moment */ +static ssize_t bfq_weights_store(struct elevator_queue *e, + const char *page, size_t count) +{ + return count; +} + +static ssize_t bfq_max_budget_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data == 0) + bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd); + else { + if (__data > INT_MAX) + __data = INT_MAX; + bfqd->bfq_max_budget = __data; + } + + bfqd->bfq_user_max_budget = __data; + + return ret; +} + +/* + * Leaving this name to preserve name compatibility with cfq + * parameters, but this timeout is used for both sync and async. + */ +static ssize_t bfq_timeout_sync_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data < 1) + __data = 1; + else if (__data > INT_MAX) + __data = INT_MAX; + + bfqd->bfq_timeout = msecs_to_jiffies(__data); + if (bfqd->bfq_user_max_budget == 0) + bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd); + + return ret; +} + +static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data > 1) + __data = 1; + if (!bfqd->strict_guarantees && __data == 1 + && bfqd->bfq_slice_idle < 8 * NSEC_PER_MSEC) + bfqd->bfq_slice_idle = 8 * NSEC_PER_MSEC; + + bfqd->strict_guarantees = __data; + + return ret; +} + +static ssize_t bfq_low_latency_store(struct elevator_queue *e, + const char *page, size_t count) +{ + struct bfq_data *bfqd = e->elevator_data; + unsigned long uninitialized_var(__data); + int ret = bfq_var_store(&__data, (page), count); + + if (__data > 1) + __data = 1; + if (__data == 0 && bfqd->low_latency != 0) + bfq_end_wr(bfqd); + bfqd->low_latency = __data; + + return ret; +} + +#define BFQ_ATTR(name) \ + __ATTR(name, S_IRUGO|S_IWUSR, bfq_##name##_show, bfq_##name##_store) + +static struct elv_fs_entry bfq_attrs[] = { + BFQ_ATTR(fifo_expire_sync), + BFQ_ATTR(fifo_expire_async), + BFQ_ATTR(back_seek_max), + BFQ_ATTR(back_seek_penalty), + BFQ_ATTR(slice_idle), + BFQ_ATTR(slice_idle_us), + BFQ_ATTR(max_budget), + BFQ_ATTR(timeout_sync), + BFQ_ATTR(strict_guarantees), + BFQ_ATTR(low_latency), + BFQ_ATTR(wr_coeff), + BFQ_ATTR(wr_max_time), + BFQ_ATTR(wr_rt_max_time), + BFQ_ATTR(wr_min_idle_time), + BFQ_ATTR(wr_min_inter_arr_async), + BFQ_ATTR(wr_max_softrt_rate), + BFQ_ATTR(weights), + __ATTR_NULL +}; + +static struct elevator_type iosched_bfq = { + .ops.sq = { + .elevator_merge_fn = bfq_merge, + .elevator_merged_fn = bfq_merged_request, + .elevator_merge_req_fn = bfq_merged_requests, +#ifdef BFQ_GROUP_IOSCHED_ENABLED + .elevator_bio_merged_fn = bfq_bio_merged, +#endif + .elevator_allow_bio_merge_fn = bfq_allow_bio_merge, + .elevator_allow_rq_merge_fn = bfq_allow_rq_merge, + .elevator_dispatch_fn = bfq_dispatch_requests, + .elevator_add_req_fn = bfq_insert_request, + .elevator_activate_req_fn = bfq_activate_request, + .elevator_deactivate_req_fn = bfq_deactivate_request, + .elevator_completed_req_fn = bfq_completed_request, + .elevator_former_req_fn = elv_rb_former_request, + .elevator_latter_req_fn = elv_rb_latter_request, + .elevator_init_icq_fn = bfq_init_icq, + .elevator_exit_icq_fn = bfq_exit_icq, + .elevator_set_req_fn = bfq_set_request, + .elevator_put_req_fn = bfq_put_request, + .elevator_may_queue_fn = bfq_may_queue, + .elevator_init_fn = bfq_init_queue, + .elevator_exit_fn = bfq_exit_queue, + }, + .icq_size = sizeof(struct bfq_io_cq), + .icq_align = __alignof__(struct bfq_io_cq), + .elevator_attrs = bfq_attrs, + .elevator_name = "bfq-sq", + .elevator_owner = THIS_MODULE, +}; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct blkcg_policy blkcg_policy_bfq = { + .dfl_cftypes = bfq_blkg_files, + .legacy_cftypes = bfq_blkcg_legacy_files, + + .cpd_alloc_fn = bfq_cpd_alloc, + .cpd_init_fn = bfq_cpd_init, + .cpd_bind_fn = bfq_cpd_init, + .cpd_free_fn = bfq_cpd_free, + + .pd_alloc_fn = bfq_pd_alloc, + .pd_init_fn = bfq_pd_init, + .pd_offline_fn = bfq_pd_offline, + .pd_free_fn = bfq_pd_free, + .pd_reset_stats_fn = bfq_pd_reset_stats, +}; +#endif + +static int __init bfq_init(void) +{ + int ret; + char msg[60] = "BFQ I/O-scheduler: v8r12"; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + ret = blkcg_policy_register(&blkcg_policy_bfq); + if (ret) + return ret; +#endif + + ret = -ENOMEM; + if (bfq_slab_setup()) + goto err_pol_unreg; + + /* + * Times to load large popular applications for the typical + * systems installed on the reference devices (see the + * comments before the definitions of the next two + * arrays). Actually, we use slightly slower values, as the + * estimated peak rate tends to be smaller than the actual + * peak rate. The reason for this last fact is that estimates + * are computed over much shorter time intervals than the long + * intervals typically used for benchmarking. Why? First, to + * adapt more quickly to variations. Second, because an I/O + * scheduler cannot rely on a peak-rate-evaluation workload to + * be run for a long time. + */ + T_slow[0] = msecs_to_jiffies(3500); /* actually 4 sec */ + T_slow[1] = msecs_to_jiffies(6000); /* actually 6.5 sec */ + T_fast[0] = msecs_to_jiffies(7000); /* actually 8 sec */ + T_fast[1] = msecs_to_jiffies(2500); /* actually 3 sec */ + + /* + * Thresholds that determine the switch between speed classes + * (see the comments before the definition of the array + * device_speed_thresh). These thresholds are biased towards + * transitions to the fast class. This is safer than the + * opposite bias. In fact, a wrong transition to the slow + * class results in short weight-raising periods, because the + * speed of the device then tends to be higher that the + * reference peak rate. On the opposite end, a wrong + * transition to the fast class tends to increase + * weight-raising periods, because of the opposite reason. + */ + device_speed_thresh[0] = (4 * R_slow[0]) / 3; + device_speed_thresh[1] = (4 * R_slow[1]) / 3; + + ret = elv_register(&iosched_bfq); + if (ret) + goto err_pol_unreg; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + strcat(msg, " (with cgroups support)"); +#endif + pr_info("%s", msg); + + return 0; + +err_pol_unreg: +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif + return ret; +} + +static void __exit bfq_exit(void) +{ + elv_unregister(&iosched_bfq); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif + bfq_slab_kill(); +} + +module_init(bfq_init); +module_exit(bfq_exit); + +MODULE_AUTHOR("Arianna Avanzini, Fabio Checconi, Paolo Valente"); +MODULE_LICENSE("GPL"); diff --git b/block/bfq.h b/block/bfq.h new file mode 100644 index 0000000..15d326f --- /dev/null +++ b/block/bfq.h @@ -0,0 +1,989 @@ +/* + * BFQ v8r12 for 4.11.0: data structures and common functions prototypes. + * + * Based on ideas and code from CFQ: + * Copyright (C) 2003 Jens Axboe + * + * Copyright (C) 2008 Fabio Checconi + * Paolo Valente + * + * Copyright (C) 2015 Paolo Valente + * + * Copyright (C) 2017 Paolo Valente + */ + +#ifndef _BFQ_H +#define _BFQ_H + +#include +#include + +/* + * Define an alternative macro to compile cgroups support. This is one + * of the steps needed to let bfq-mq share the files bfq-sched.c and + * bfq-cgroup.c with bfq-sq. For bfq-mq, the macro + * BFQ_GROUP_IOSCHED_ENABLED will be defined as a function of whether + * the configuration option CONFIG_BFQ_MQ_GROUP_IOSCHED, and not + * CONFIG_BFQ_GROUP_IOSCHED, is defined. + */ +#ifdef CONFIG_BFQ_SQ_GROUP_IOSCHED +#define BFQ_GROUP_IOSCHED_ENABLED +#endif + +#define BFQ_IOPRIO_CLASSES 3 +#define BFQ_CL_IDLE_TIMEOUT (HZ/5) + +#define BFQ_MIN_WEIGHT 1 +#define BFQ_MAX_WEIGHT 1000 +#define BFQ_WEIGHT_CONVERSION_COEFF 10 + +#define BFQ_DEFAULT_QUEUE_IOPRIO 4 + +#define BFQ_WEIGHT_LEGACY_DFL 100 +#define BFQ_DEFAULT_GRP_IOPRIO 0 +#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE + +/* + * Soft real-time applications are extremely more latency sensitive + * than interactive ones. Over-raise the weight of the former to + * privilege them against the latter. + */ +#define BFQ_SOFTRT_WEIGHT_FACTOR 100 + +struct bfq_entity; + +/** + * struct bfq_service_tree - per ioprio_class service tree. + * + * Each service tree represents a B-WF2Q+ scheduler on its own. Each + * ioprio_class has its own independent scheduler, and so its own + * bfq_service_tree. All the fields are protected by the queue lock + * of the containing bfqd. + */ +struct bfq_service_tree { + /* tree for active entities (i.e., those backlogged) */ + struct rb_root active; + /* tree for idle entities (i.e., not backlogged, with V <= F_i)*/ + struct rb_root idle; + + struct bfq_entity *first_idle; /* idle entity with minimum F_i */ + struct bfq_entity *last_idle; /* idle entity with maximum F_i */ + + u64 vtime; /* scheduler virtual time */ + /* scheduler weight sum; active and idle entities contribute to it */ + unsigned long wsum; +}; + +/** + * struct bfq_sched_data - multi-class scheduler. + * + * bfq_sched_data is the basic scheduler queue. It supports three + * ioprio_classes, and can be used either as a toplevel queue or as an + * intermediate queue in a hierarchical setup. + * + * The supported ioprio_classes are the same as in CFQ, in descending + * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE. + * Requests from higher priority queues are served before all the + * requests from lower priority queues; among requests of the same + * queue requests are served according to B-WF2Q+. + * + * The schedule is implemented by the service trees, plus the field + * @next_in_service, which points to the entity on the active trees + * that will be served next, if 1) no changes in the schedule occurs + * before the current in-service entity is expired, 2) the in-service + * queue becomes idle when it expires, and 3) if the entity pointed by + * in_service_entity is not a queue, then the in-service child entity + * of the entity pointed by in_service_entity becomes idle on + * expiration. This peculiar definition allows for the following + * optimization, not yet exploited: while a given entity is still in + * service, we already know which is the best candidate for next + * service among the other active entitities in the same parent + * entity. We can then quickly compare the timestamps of the + * in-service entity with those of such best candidate. + * + * All the fields are protected by the queue lock of the containing + * bfqd. + */ +struct bfq_sched_data { + struct bfq_entity *in_service_entity; /* entity in service */ + /* head-of-the-line entity in the scheduler (see comments above) */ + struct bfq_entity *next_in_service; + /* array of service trees, one per ioprio_class */ + struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES]; + /* last time CLASS_IDLE was served */ + unsigned long bfq_class_idle_last_service; + +}; + +/** + * struct bfq_weight_counter - counter of the number of all active entities + * with a given weight. + */ +struct bfq_weight_counter { + unsigned int weight; /* weight of the entities this counter refers to */ + unsigned int num_active; /* nr of active entities with this weight */ + /* + * Weights tree member (see bfq_data's @queue_weights_tree and + * @group_weights_tree) + */ + struct rb_node weights_node; +}; + +/** + * struct bfq_entity - schedulable entity. + * + * A bfq_entity is used to represent either a bfq_queue (leaf node in the + * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each + * entity belongs to the sched_data of the parent group in the cgroup + * hierarchy. Non-leaf entities have also their own sched_data, stored + * in @my_sched_data. + * + * Each entity stores independently its priority values; this would + * allow different weights on different devices, but this + * functionality is not exported to userspace by now. Priorities and + * weights are updated lazily, first storing the new values into the + * new_* fields, then setting the @prio_changed flag. As soon as + * there is a transition in the entity state that allows the priority + * update to take place the effective and the requested priority + * values are synchronized. + * + * Unless cgroups are used, the weight value is calculated from the + * ioprio to export the same interface as CFQ. When dealing with + * ``well-behaved'' queues (i.e., queues that do not spend too much + * time to consume their budget and have true sequential behavior, and + * when there are no external factors breaking anticipation) the + * relative weights at each level of the cgroups hierarchy should be + * guaranteed. All the fields are protected by the queue lock of the + * containing bfqd. + */ +struct bfq_entity { + struct rb_node rb_node; /* service_tree member */ + /* pointer to the weight counter associated with this entity */ + struct bfq_weight_counter *weight_counter; + + /* + * Flag, true if the entity is on a tree (either the active or + * the idle one of its service_tree) or is in service. + */ + bool on_st; + + u64 finish; /* B-WF2Q+ finish timestamp (aka F_i) */ + u64 start; /* B-WF2Q+ start timestamp (aka S_i) */ + + /* tree the entity is enqueued into; %NULL if not on a tree */ + struct rb_root *tree; + + /* + * minimum start time of the (active) subtree rooted at this + * entity; used for O(log N) lookups into active trees + */ + u64 min_start; + + /* amount of service received during the last service slot */ + int service; + + /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ + int budget; + + unsigned int weight; /* weight of the queue */ + unsigned int new_weight; /* next weight if a change is in progress */ + + /* original weight, used to implement weight boosting */ + unsigned int orig_weight; + + /* parent entity, for hierarchical scheduling */ + struct bfq_entity *parent; + + /* + * For non-leaf nodes in the hierarchy, the associated + * scheduler queue, %NULL on leaf nodes. + */ + struct bfq_sched_data *my_sched_data; + /* the scheduler queue this entity belongs to */ + struct bfq_sched_data *sched_data; + + /* flag, set to request a weight, ioprio or ioprio_class change */ + int prio_changed; +}; + +struct bfq_group; + +/** + * struct bfq_queue - leaf schedulable entity. + * + * A bfq_queue is a leaf request queue; it can be associated with an + * io_context or more, if it is async or shared between cooperating + * processes. @cgroup holds a reference to the cgroup, to be sure that it + * does not disappear while a bfqq still references it (mostly to avoid + * races between request issuing and task migration followed by cgroup + * destruction). + * All the fields are protected by the queue lock of the containing bfqd. + */ +struct bfq_queue { + /* reference counter */ + int ref; + /* parent bfq_data */ + struct bfq_data *bfqd; + + /* current ioprio and ioprio class */ + unsigned short ioprio, ioprio_class; + /* next ioprio and ioprio class if a change is in progress */ + unsigned short new_ioprio, new_ioprio_class; + + /* + * Shared bfq_queue if queue is cooperating with one or more + * other queues. + */ + struct bfq_queue *new_bfqq; + /* request-position tree member (see bfq_group's @rq_pos_tree) */ + struct rb_node pos_node; + /* request-position tree root (see bfq_group's @rq_pos_tree) */ + struct rb_root *pos_root; + + /* sorted list of pending requests */ + struct rb_root sort_list; + /* if fifo isn't expired, next request to serve */ + struct request *next_rq; + /* number of sync and async requests queued */ + int queued[2]; + /* number of sync and async requests currently allocated */ + int allocated[2]; + /* number of pending metadata requests */ + int meta_pending; + /* fifo list of requests in sort_list */ + struct list_head fifo; + + /* entity representing this queue in the scheduler */ + struct bfq_entity entity; + + /* maximum budget allowed from the feedback mechanism */ + int max_budget; + /* budget expiration (in jiffies) */ + unsigned long budget_timeout; + + /* number of requests on the dispatch list or inside driver */ + int dispatched; + + unsigned int flags; /* status flags.*/ + + /* node for active/idle bfqq list inside parent bfqd */ + struct list_head bfqq_list; + + /* bit vector: a 1 for each seeky requests in history */ + u32 seek_history; + + /* node for the device's burst list */ + struct hlist_node burst_list_node; + + /* position of the last request enqueued */ + sector_t last_request_pos; + + /* Number of consecutive pairs of request completion and + * arrival, such that the queue becomes idle after the + * completion, but the next request arrives within an idle + * time slice; used only if the queue's IO_bound flag has been + * cleared. + */ + unsigned int requests_within_timer; + + /* pid of the process owning the queue, used for logging purposes */ + pid_t pid; + + /* + * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL + * if the queue is shared. + */ + struct bfq_io_cq *bic; + + /* current maximum weight-raising time for this queue */ + unsigned long wr_cur_max_time; + /* + * Minimum time instant such that, only if a new request is + * enqueued after this time instant in an idle @bfq_queue with + * no outstanding requests, then the task associated with the + * queue it is deemed as soft real-time (see the comments on + * the function bfq_bfqq_softrt_next_start()) + */ + unsigned long soft_rt_next_start; + /* + * Start time of the current weight-raising period if + * the @bfq-queue is being weight-raised, otherwise + * finish time of the last weight-raising period. + */ + unsigned long last_wr_start_finish; + /* factor by which the weight of this queue is multiplied */ + unsigned int wr_coeff; + /* + * Time of the last transition of the @bfq_queue from idle to + * backlogged. + */ + unsigned long last_idle_bklogged; + /* + * Cumulative service received from the @bfq_queue since the + * last transition from idle to backlogged. + */ + unsigned long service_from_backlogged; + /* + * Value of wr start time when switching to soft rt + */ + unsigned long wr_start_at_switch_to_srt; + + unsigned long split_time; /* time of last split */ +}; + +/** + * struct bfq_ttime - per process thinktime stats. + */ +struct bfq_ttime { + u64 last_end_request; /* completion time of last request */ + + u64 ttime_total; /* total process thinktime */ + unsigned long ttime_samples; /* number of thinktime samples */ + u64 ttime_mean; /* average process thinktime */ + +}; + +/** + * struct bfq_io_cq - per (request_queue, io_context) structure. + */ +struct bfq_io_cq { + /* associated io_cq structure */ + struct io_cq icq; /* must be the first member */ + /* array of two process queues, the sync and the async */ + struct bfq_queue *bfqq[2]; + /* associated @bfq_ttime struct */ + struct bfq_ttime ttime; + /* per (request_queue, blkcg) ioprio */ + int ioprio; +#ifdef BFQ_GROUP_IOSCHED_ENABLED + uint64_t blkcg_serial_nr; /* the current blkcg serial */ +#endif + + /* + * Snapshot of the has_short_time flag before merging; taken + * to remember its value while the queue is merged, so as to + * be able to restore it in case of split. + */ + bool saved_has_short_ttime; + /* + * Same purpose as the previous two fields for the I/O bound + * classification of a queue. + */ + bool saved_IO_bound; + + /* + * Same purpose as the previous fields for the value of the + * field keeping the queue's belonging to a large burst + */ + bool saved_in_large_burst; + /* + * True if the queue belonged to a burst list before its merge + * with another cooperating queue. + */ + bool was_in_burst_list; + + /* + * Similar to previous fields: save wr information. + */ + unsigned long saved_wr_coeff; + unsigned long saved_last_wr_start_finish; + unsigned long saved_wr_start_at_switch_to_srt; + unsigned int saved_wr_cur_max_time; +}; + +enum bfq_device_speed { + BFQ_BFQD_FAST, + BFQ_BFQD_SLOW, +}; + +/** + * struct bfq_data - per-device data structure. + * + * All the fields are protected by the @queue lock. + */ +struct bfq_data { + /* request queue for the device */ + struct request_queue *queue; + + /* root bfq_group for the device */ + struct bfq_group *root_group; + + /* + * rbtree of weight counters of @bfq_queues, sorted by + * weight. Used to keep track of whether all @bfq_queues have + * the same weight. The tree contains one counter for each + * distinct weight associated to some active and not + * weight-raised @bfq_queue (see the comments to the functions + * bfq_weights_tree_[add|remove] for further details). + */ + struct rb_root queue_weights_tree; + /* + * rbtree of non-queue @bfq_entity weight counters, sorted by + * weight. Used to keep track of whether all @bfq_groups have + * the same weight. The tree contains one counter for each + * distinct weight associated to some active @bfq_group (see + * the comments to the functions bfq_weights_tree_[add|remove] + * for further details). + */ + struct rb_root group_weights_tree; + + /* + * Number of bfq_queues containing requests (including the + * queue in service, even if it is idling). + */ + int busy_queues; + /* number of weight-raised busy @bfq_queues */ + int wr_busy_queues; + /* number of queued requests */ + int queued; + /* number of requests dispatched and waiting for completion */ + int rq_in_driver; + + /* + * Maximum number of requests in driver in the last + * @hw_tag_samples completed requests. + */ + int max_rq_in_driver; + /* number of samples used to calculate hw_tag */ + int hw_tag_samples; + /* flag set to one if the driver is showing a queueing behavior */ + int hw_tag; + + /* number of budgets assigned */ + int budgets_assigned; + + /* + * Timer set when idling (waiting) for the next request from + * the queue in service. + */ + struct hrtimer idle_slice_timer; + /* delayed work to restart dispatching on the request queue */ + struct work_struct unplug_work; + + /* bfq_queue in service */ + struct bfq_queue *in_service_queue; + /* bfq_io_cq (bic) associated with the @in_service_queue */ + struct bfq_io_cq *in_service_bic; + + /* on-disk position of the last served request */ + sector_t last_position; + + /* time of last request completion (ns) */ + u64 last_completion; + + /* time of first rq dispatch in current observation interval (ns) */ + u64 first_dispatch; + /* time of last rq dispatch in current observation interval (ns) */ + u64 last_dispatch; + + /* beginning of the last budget */ + ktime_t last_budget_start; + /* beginning of the last idle slice */ + ktime_t last_idling_start; + + /* number of samples in current observation interval */ + int peak_rate_samples; + /* num of samples of seq dispatches in current observation interval */ + u32 sequential_samples; + /* total num of sectors transferred in current observation interval */ + u64 tot_sectors_dispatched; + /* max rq size seen during current observation interval (sectors) */ + u32 last_rq_max_size; + /* time elapsed from first dispatch in current observ. interval (us) */ + u64 delta_from_first; + /* current estimate of device peak rate */ + u32 peak_rate; + + /* maximum budget allotted to a bfq_queue before rescheduling */ + int bfq_max_budget; + + /* list of all the bfq_queues active on the device */ + struct list_head active_list; + /* list of all the bfq_queues idle on the device */ + struct list_head idle_list; + + /* + * Timeout for async/sync requests; when it fires, requests + * are served in fifo order. + */ + u64 bfq_fifo_expire[2]; + /* weight of backward seeks wrt forward ones */ + unsigned int bfq_back_penalty; + /* maximum allowed backward seek */ + unsigned int bfq_back_max; + /* maximum idling time */ + u32 bfq_slice_idle; + + /* user-configured max budget value (0 for auto-tuning) */ + int bfq_user_max_budget; + /* + * Timeout for bfq_queues to consume their budget; used to + * prevent seeky queues from imposing long latencies to + * sequential or quasi-sequential ones (this also implies that + * seeky queues cannot receive guarantees in the service + * domain; after a timeout they are charged for the time they + * have been in service, to preserve fairness among them, but + * without service-domain guarantees). + */ + unsigned int bfq_timeout; + + /* + * Number of consecutive requests that must be issued within + * the idle time slice to set again idling to a queue which + * was marked as non-I/O-bound (see the definition of the + * IO_bound flag for further details). + */ + unsigned int bfq_requests_within_timer; + + /* + * Force device idling whenever needed to provide accurate + * service guarantees, without caring about throughput + * issues. CAVEAT: this may even increase latencies, in case + * of useless idling for processes that did stop doing I/O. + */ + bool strict_guarantees; + + /* + * Last time at which a queue entered the current burst of + * queues being activated shortly after each other; for more + * details about this and the following parameters related to + * a burst of activations, see the comments on the function + * bfq_handle_burst. + */ + unsigned long last_ins_in_burst; + /* + * Reference time interval used to decide whether a queue has + * been activated shortly after @last_ins_in_burst. + */ + unsigned long bfq_burst_interval; + /* number of queues in the current burst of queue activations */ + int burst_size; + + /* common parent entity for the queues in the burst */ + struct bfq_entity *burst_parent_entity; + /* Maximum burst size above which the current queue-activation + * burst is deemed as 'large'. + */ + unsigned long bfq_large_burst_thresh; + /* true if a large queue-activation burst is in progress */ + bool large_burst; + /* + * Head of the burst list (as for the above fields, more + * details in the comments on the function bfq_handle_burst). + */ + struct hlist_head burst_list; + + /* if set to true, low-latency heuristics are enabled */ + bool low_latency; + /* + * Maximum factor by which the weight of a weight-raised queue + * is multiplied. + */ + unsigned int bfq_wr_coeff; + /* maximum duration of a weight-raising period (jiffies) */ + unsigned int bfq_wr_max_time; + + /* Maximum weight-raising duration for soft real-time processes */ + unsigned int bfq_wr_rt_max_time; + /* + * Minimum idle period after which weight-raising may be + * reactivated for a queue (in jiffies). + */ + unsigned int bfq_wr_min_idle_time; + /* + * Minimum period between request arrivals after which + * weight-raising may be reactivated for an already busy async + * queue (in jiffies). + */ + unsigned long bfq_wr_min_inter_arr_async; + + /* Max service-rate for a soft real-time queue, in sectors/sec */ + unsigned int bfq_wr_max_softrt_rate; + /* + * Cached value of the product R*T, used for computing the + * maximum duration of weight raising automatically. + */ + u64 RT_prod; + /* device-speed class for the low-latency heuristic */ + enum bfq_device_speed device_speed; + + /* fallback dummy bfqq for extreme OOM conditions */ + struct bfq_queue oom_bfqq; +}; + +enum bfqq_state_flags { + BFQ_BFQQ_FLAG_just_created = 0, /* queue just allocated */ + BFQ_BFQQ_FLAG_busy, /* has requests or is in service */ + BFQ_BFQQ_FLAG_wait_request, /* waiting for a request */ + BFQ_BFQQ_FLAG_non_blocking_wait_rq, /* + * waiting for a request + * without idling the device + */ + BFQ_BFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ + BFQ_BFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ + BFQ_BFQQ_FLAG_has_short_ttime, /* queue has a short think time */ + BFQ_BFQQ_FLAG_sync, /* synchronous queue */ + BFQ_BFQQ_FLAG_IO_bound, /* + * bfqq has timed-out at least once + * having consumed at most 2/10 of + * its budget + */ + BFQ_BFQQ_FLAG_in_large_burst, /* + * bfqq activated in a large burst, + * see comments to bfq_handle_burst. + */ + BFQ_BFQQ_FLAG_softrt_update, /* + * may need softrt-next-start + * update + */ + BFQ_BFQQ_FLAG_coop, /* bfqq is shared */ + BFQ_BFQQ_FLAG_split_coop /* shared bfqq will be split */ +}; + +#define BFQ_BFQQ_FNS(name) \ +static void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ +{ \ + (bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \ +} \ +static void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ +{ \ + (bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \ +} \ +static int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ +{ \ + return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \ +} + +BFQ_BFQQ_FNS(just_created); +BFQ_BFQQ_FNS(busy); +BFQ_BFQQ_FNS(wait_request); +BFQ_BFQQ_FNS(non_blocking_wait_rq); +BFQ_BFQQ_FNS(must_alloc); +BFQ_BFQQ_FNS(fifo_expire); +BFQ_BFQQ_FNS(has_short_ttime); +BFQ_BFQQ_FNS(sync); +BFQ_BFQQ_FNS(IO_bound); +BFQ_BFQQ_FNS(in_large_burst); +BFQ_BFQQ_FNS(coop); +BFQ_BFQQ_FNS(split_coop); +BFQ_BFQQ_FNS(softrt_update); +#undef BFQ_BFQQ_FNS + +/* Logging facilities. */ +#ifdef CONFIG_BFQ_REDIRECT_TO_CONSOLE + +static const char *checked_dev_name(const struct device *dev) +{ + static const char nodev[] = "nodev"; + + if (dev) + return dev_name(dev); + + return nodev; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ + char __pbuf[128]; \ + \ + assert_spin_locked((bfqd)->queue->queue_lock); \ + blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \ + pr_crit("%s bfq%d%c %s " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + __pbuf, ##args); \ +} while (0) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ + char __pbuf[128]; \ + \ + blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \ + pr_crit("%s %s " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + __pbuf, ##args); \ +} while (0) + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ + pr_crit("%s bfq%d%c " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + (bfqq)->pid, bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + ##args) +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) + +#endif /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log(bfqd, fmt, args...) \ + pr_crit("%s bfq " fmt "\n", \ + checked_dev_name((bfqd)->queue->backing_dev_info->dev), \ + ##args) + +#else /* CONFIG_BFQ_REDIRECT_TO_CONSOLE */ + +#if !defined(CONFIG_BLK_DEV_IO_TRACE) + +/* Avoid possible "unused-variable" warning. See commit message. */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) ((void) (bfqq)) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) ((void) (bfqg)) + +#define bfq_log(bfqd, fmt, args...) do {} while (0) + +#else /* CONFIG_BLK_DEV_IO_TRACE */ + +#include + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ + char __pbuf[128]; \ + \ + assert_spin_locked((bfqd)->queue->queue_lock); \ + blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \ + blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, \ + (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + __pbuf, ##args); \ +} while (0) + +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ + char __pbuf[128]; \ + \ + blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \ + blk_add_trace_msg((bfqd)->queue, "%s " fmt, __pbuf, ##args); \ +} while (0) + +#else /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ + blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ + bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ + ##args) +#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) + +#endif /* BFQ_GROUP_IOSCHED_ENABLED */ + +#define bfq_log(bfqd, fmt, args...) \ + blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) + +#endif /* CONFIG_BLK_DEV_IO_TRACE */ +#endif /* CONFIG_BFQ_REDIRECT_TO_CONSOLE */ + +/* Expiration reasons. */ +enum bfqq_expiration { + BFQ_BFQQ_TOO_IDLE = 0, /* + * queue has been idling for + * too long + */ + BFQ_BFQQ_BUDGET_TIMEOUT, /* budget took too long to be used */ + BFQ_BFQQ_BUDGET_EXHAUSTED, /* budget consumed */ + BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */ + BFQ_BFQQ_PREEMPTED /* preemption in progress */ +}; + + +struct bfqg_stats { +#ifdef BFQ_GROUP_IOSCHED_ENABLED + /* number of ios merged */ + struct blkg_rwstat merged; + /* total time spent on device in ns, may not be accurate w/ queueing */ + struct blkg_rwstat service_time; + /* total time spent waiting in scheduler queue in ns */ + struct blkg_rwstat wait_time; + /* number of IOs queued up */ + struct blkg_rwstat queued; + /* total disk time and nr sectors dispatched by this group */ + struct blkg_stat time; + /* sum of number of ios queued across all samples */ + struct blkg_stat avg_queue_size_sum; + /* count of samples taken for average */ + struct blkg_stat avg_queue_size_samples; + /* how many times this group has been removed from service tree */ + struct blkg_stat dequeue; + /* total time spent waiting for it to be assigned a timeslice. */ + struct blkg_stat group_wait_time; + /* time spent idling for this blkcg_gq */ + struct blkg_stat idle_time; + /* total time with empty current active q with other requests queued */ + struct blkg_stat empty_time; + /* fields after this shouldn't be cleared on stat reset */ + uint64_t start_group_wait_time; + uint64_t start_idle_time; + uint64_t start_empty_time; + uint16_t flags; +#endif +}; + +#ifdef BFQ_GROUP_IOSCHED_ENABLED +/* + * struct bfq_group_data - per-blkcg storage for the blkio subsystem. + * + * @ps: @blkcg_policy_storage that this structure inherits + * @weight: weight of the bfq_group + */ +struct bfq_group_data { + /* must be the first member */ + struct blkcg_policy_data pd; + + unsigned int weight; +}; + +/** + * struct bfq_group - per (device, cgroup) data structure. + * @entity: schedulable entity to insert into the parent group sched_data. + * @sched_data: own sched_data, to contain child entities (they may be + * both bfq_queues and bfq_groups). + * @bfqd: the bfq_data for the device this group acts upon. + * @async_bfqq: array of async queues for all the tasks belonging to + * the group, one queue per ioprio value per ioprio_class, + * except for the idle class that has only one queue. + * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). + * @my_entity: pointer to @entity, %NULL for the toplevel group; used + * to avoid too many special cases during group creation/ + * migration. + * @active_entities: number of active entities belonging to the group; + * unused for the root group. Used to know whether there + * are groups with more than one active @bfq_entity + * (see the comments to the function + * bfq_bfqq_may_idle()). + * @rq_pos_tree: rbtree sorted by next_request position, used when + * determining if two or more queues have interleaving + * requests (see bfq_find_close_cooperator()). + * + * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup + * there is a set of bfq_groups, each one collecting the lower-level + * entities belonging to the group that are acting on the same device. + * + * Locking works as follows: + * o @bfqd is protected by the queue lock, RCU is used to access it + * from the readers. + * o All the other fields are protected by the @bfqd queue lock. + */ +struct bfq_group { + /* must be the first member */ + struct blkg_policy_data pd; + + struct bfq_entity entity; + struct bfq_sched_data sched_data; + + void *bfqd; + + struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; + struct bfq_queue *async_idle_bfqq; + + struct bfq_entity *my_entity; + + int active_entities; + + struct rb_root rq_pos_tree; + + struct bfqg_stats stats; +}; + +#else +struct bfq_group { + struct bfq_sched_data sched_data; + + struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; + struct bfq_queue *async_idle_bfqq; + + struct rb_root rq_pos_tree; +}; +#endif + +static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); + +static unsigned int bfq_class_idx(struct bfq_entity *entity) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + + return bfqq ? bfqq->ioprio_class - 1 : + BFQ_DEFAULT_GRP_CLASS - 1; +} + +static struct bfq_service_tree * +bfq_entity_service_tree(struct bfq_entity *entity) +{ + struct bfq_sched_data *sched_data = entity->sched_data; + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + unsigned int idx = bfq_class_idx(entity); + + BUG_ON(idx >= BFQ_IOPRIO_CLASSES); + BUG_ON(sched_data == NULL); + + if (bfqq) + bfq_log_bfqq(bfqq->bfqd, bfqq, + "entity_service_tree %p %d", + sched_data->service_tree + idx, idx); +#ifdef BFQ_GROUP_IOSCHED_ENABLED + else { + struct bfq_group *bfqg = + container_of(entity, struct bfq_group, entity); + + bfq_log_bfqg((struct bfq_data *)bfqg->bfqd, bfqg, + "entity_service_tree %p %d", + sched_data->service_tree + idx, idx); + } +#endif + return sched_data->service_tree + idx; +} + +static struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync) +{ + return bic->bfqq[is_sync]; +} + +static void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, + bool is_sync) +{ + bic->bfqq[is_sync] = bfqq; +} + +static struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) +{ + return bic->icq.q->elevator->elevator_data; +} + +#ifdef BFQ_GROUP_IOSCHED_ENABLED + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + struct bfq_entity *group_entity = bfqq->entity.parent; + + if (!group_entity) + group_entity = &bfqq->bfqd->root_group->entity; + + return container_of(group_entity, struct bfq_group, entity); +} + +#else + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + return bfqq->bfqd->root_group; +} + +#endif + +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio); +static void bfq_put_queue(struct bfq_queue *bfqq); +static void bfq_dispatch_insert(struct request_queue *q, struct request *rq); +static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, + struct bio *bio, bool is_sync, + struct bfq_io_cq *bic); +static void bfq_end_wr_async_queues(struct bfq_data *bfqd, + struct bfq_group *bfqg); +#ifdef BFQ_GROUP_IOSCHED_ENABLED +static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); +#endif +static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); + +#endif /* _BFQ_H */ diff --git a/block/blk-core.c b/block/blk-core.c index 658f673..b160ce2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -55,6 +55,8 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); DEFINE_IDA(blk_queue_ida); +int trap_non_toi_io; + /* * For the allocated request tables */ @@ -2236,6 +2238,9 @@ EXPORT_SYMBOL(generic_make_request); */ blk_qc_t submit_bio(struct bio *bio) { + if (unlikely(trap_non_toi_io)) + BUG_ON(!bio_flagged(bio, BIO_TOI)); + /* * If it's a regular read/write or a barrier with data attached, * go through the normal accounting stuff before submission. diff --git a/block/elevator.c b/block/elevator.c index 4bb2f0c..32e6024 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -229,7 +229,11 @@ int elevator_init(struct request_queue *q, char *name) */ if (q->mq_ops) { if (q->nr_hw_queues == 1) + #if defined(CONFIG_PCK_INTERACTIVE) && defined(CONFIG_IOSCHED_BFQ) + e = elevator_get("bfq", false); + #else e = elevator_get("mq-deadline", false); + #endif if (!e) return 0; } else diff --git a/block/genhd.c b/block/genhd.c index 7f520fa..537f6a5 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -18,6 +18,8 @@ #include #include #include +#include +#include #include #include #include @@ -1441,6 +1443,85 @@ int invalidate_partition(struct gendisk *disk, int partno) EXPORT_SYMBOL(invalidate_partition); +dev_t blk_lookup_fs_info(struct fs_info *seek) +{ + dev_t devt = MKDEV(0, 0); + struct class_dev_iter iter; + struct device *dev; + int best_score = 0; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while (best_score < 3 && (dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; + + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0); + + while (best_score < 3 && (part = disk_part_iter_next(&piter))) { + int score = part_matches_fs_info(part, seek); + if (score > best_score) { + devt = part_devt(part); + best_score = score; + } + } + disk_part_iter_exit(&piter); + } + class_dev_iter_exit(&iter); + return devt; +} + +/* Caller uses NULL, key to start. For each match found, we return a bdev on + * which we have done blkdev_get, and we do the blkdev_put on block devices + * that are passed to us. When no more matches are found, we return NULL. + */ +struct block_device *next_bdev_of_type(struct block_device *last, + const char *key) +{ + dev_t devt = MKDEV(0, 0); + struct class_dev_iter iter; + struct device *dev; + struct block_device *next = NULL, *bdev; + int got_last = 0; + + if (!key) + goto out; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while (!devt && (dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; + + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0); + + while ((part = disk_part_iter_next(&piter))) { + bdev = bdget(part_devt(part)); + if (last && !got_last) { + if (last == bdev) + got_last = 1; + continue; + } + + if (blkdev_get(bdev, FMODE_READ, 0)) + continue; + + if (bdev_matches_key(bdev, key)) { + next = bdev; + break; + } + + blkdev_put(bdev, FMODE_READ); + } + disk_part_iter_exit(&piter); + } + class_dev_iter_exit(&iter); +out: + if (last) + blkdev_put(last, FMODE_READ); + return next; +} + /* * Disk events - monitor disk events like media change and eject request. */ diff --git b/block/uuid.c b/block/uuid.c new file mode 100644 index 0000000..5e33819 --- /dev/null +++ b/block/uuid.c @@ -0,0 +1,510 @@ +#include +#include +#include +#include +#include + +static int debug_enabled; + +#define PRINTK(fmt, args...) do { \ + if (debug_enabled) \ + printk(KERN_DEBUG fmt, ## args); \ + } while(0) + +#define PRINT_HEX_DUMP(v1, v2, v3, v4, v5, v6, v7, v8) \ + do { \ + if (debug_enabled) \ + print_hex_dump(v1, v2, v3, v4, v5, v6, v7, v8); \ + } while(0) + +/* + * Simple UUID translation + */ + +struct uuid_info { + const char *key; + const char *name; + long bkoff; + unsigned sboff; + unsigned sig_len; + const char *magic; + int uuid_offset; + int last_mount_offset; + int last_mount_size; +}; + +/* + * Based on libuuid's blkid_magic array. Note that I don't + * have uuid offsets for all of these yet - mssing ones are 0x0. + * Further information welcome. + * + * Rearranged by page of fs signature for optimisation. + */ +static struct uuid_info uuid_list[] = { + { NULL, "oracleasm", 0, 32, 8, "ORCLDISK", 0x0, 0, 0 }, + { "ntfs", "ntfs", 0, 3, 8, "NTFS ", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x52, 5, "MSWIN", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x52, 8, "FAT32 ", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x36, 5, "MSDOS", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x36, 8, "FAT16 ", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x36, 8, "FAT12 ", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0, 1, "\353", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0, 1, "\351", 0x0, 0, 0 }, + { "vfat", "vfat", 0, 0x1fe, 2, "\125\252", 0x0, 0, 0 }, + { "xfs", "xfs", 0, 0, 4, "XFSB", 0x20, 0, 0 }, + { "romfs", "romfs", 0, 0, 8, "-rom1fs-", 0x0, 0, 0 }, + { "bfs", "bfs", 0, 0, 4, "\316\372\173\033", 0, 0, 0 }, + { "cramfs", "cramfs", 0, 0, 4, "E=\315\050", 0x0, 0, 0 }, + { "qnx4", "qnx4", 0, 4, 6, "QNX4FS", 0, 0, 0 }, + { NULL, "crypt_LUKS", 0, 0, 6, "LUKS\xba\xbe", 0x0, 0, 0 }, + { "squashfs", "squashfs", 0, 0, 4, "sqsh", 0, 0, 0 }, + { "squashfs", "squashfs", 0, 0, 4, "hsqs", 0, 0, 0 }, + { "ocfs", "ocfs", 0, 8, 9, "OracleCFS", 0x0, 0, 0 }, + { "lvm2pv", "lvm2pv", 0, 0x018, 8, "LVM2 001", 0x0, 0, 0 }, + { "sysv", "sysv", 0, 0x3f8, 4, "\020~\030\375", 0, 0, 0 }, + { "ext", "ext", 1, 0x38, 2, "\123\357", 0x468, 0x42c, 4 }, + { "minix", "minix", 1, 0x10, 2, "\177\023", 0, 0, 0 }, + { "minix", "minix", 1, 0x10, 2, "\217\023", 0, 0, 0 }, + { "minix", "minix", 1, 0x10, 2, "\150\044", 0, 0, 0 }, + { "minix", "minix", 1, 0x10, 2, "\170\044", 0, 0, 0 }, + { "lvm2pv", "lvm2pv", 1, 0x018, 8, "LVM2 001", 0x0, 0, 0 }, + { "vxfs", "vxfs", 1, 0, 4, "\365\374\001\245", 0, 0, 0 }, + { "hfsplus", "hfsplus", 1, 0, 2, "BD", 0x0, 0, 0 }, + { "hfsplus", "hfsplus", 1, 0, 2, "H+", 0x0, 0, 0 }, + { "hfsplus", "hfsplus", 1, 0, 2, "HX", 0x0, 0, 0 }, + { "hfs", "hfs", 1, 0, 2, "BD", 0x0, 0, 0 }, + { "ocfs2", "ocfs2", 1, 0, 6, "OCFSV2", 0x0, 0, 0 }, + { "lvm2pv", "lvm2pv", 0, 0x218, 8, "LVM2 001", 0x0, 0, 0 }, + { "lvm2pv", "lvm2pv", 1, 0x218, 8, "LVM2 001", 0x0, 0, 0 }, + { "ocfs2", "ocfs2", 2, 0, 6, "OCFSV2", 0x0, 0, 0 }, + { "swap", "swap", 0, 0xff6, 10, "SWAP-SPACE", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0xff6, 10, "SWAPSPACE2", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xff6, 9, "S1SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xff6, 9, "S2SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xff6, 9, "ULSUSPEND", 0x40c, 0, 0 }, + { "ocfs2", "ocfs2", 4, 0, 6, "OCFSV2", 0x0, 0, 0 }, + { "ocfs2", "ocfs2", 8, 0, 6, "OCFSV2", 0x0, 0, 0 }, + { "hpfs", "hpfs", 8, 0, 4, "I\350\225\371", 0, 0, 0 }, + { "reiserfs", "reiserfs", 8, 0x34, 8, "ReIsErFs", 0x10054, 0, 0 }, + { "reiserfs", "reiserfs", 8, 20, 8, "ReIsErFs", 0x10054, 0, 0 }, + { "zfs", "zfs", 8, 0, 8, "\0\0\x02\xf5\xb0\x07\xb1\x0c", 0x0, 0, 0 }, + { "zfs", "zfs", 8, 0, 8, "\x0c\xb1\x07\xb0\xf5\x02\0\0", 0x0, 0, 0 }, + { "ufs", "ufs", 8, 0x55c, 4, "T\031\001\000", 0, 0, 0 }, + { "swap", "swap", 0, 0x1ff6, 10, "SWAP-SPACE", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0x1ff6, 10, "SWAPSPACE2", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x1ff6, 9, "S1SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x1ff6, 9, "S2SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x1ff6, 9, "ULSUSPEND", 0x40c, 0, 0 }, + { "reiserfs", "reiserfs", 64, 0x34, 9, "ReIsEr2Fs", 0x10054, 0, 0 }, + { "reiserfs", "reiserfs", 64, 0x34, 9, "ReIsEr3Fs", 0x10054, 0, 0 }, + { "reiserfs", "reiserfs", 64, 0x34, 8, "ReIsErFs", 0x10054, 0, 0 }, + { "reiser4", "reiser4", 64, 0, 7, "ReIsEr4", 0x100544, 0, 0 }, + { "gfs2", "gfs2", 64, 0, 4, "\x01\x16\x19\x70", 0x0, 0, 0 }, + { "gfs", "gfs", 64, 0, 4, "\x01\x16\x19\x70", 0x0, 0, 0 }, + { "btrfs", "btrfs", 64, 0x40, 8, "_BHRfS_M", 0x0, 0, 0 }, + { "swap", "swap", 0, 0x3ff6, 10, "SWAP-SPACE", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0x3ff6, 10, "SWAPSPACE2", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x3ff6, 9, "S1SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x3ff6, 9, "S2SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x3ff6, 9, "ULSUSPEND", 0x40c, 0, 0 }, + { "udf", "udf", 32, 1, 5, "BEA01", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "BOOT2", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "CD001", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "CDW02", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "NSR02", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "NSR03", 0x0, 0, 0 }, + { "udf", "udf", 32, 1, 5, "TEA01", 0x0, 0, 0 }, + { "iso9660", "iso9660", 32, 1, 5, "CD001", 0x0, 0, 0 }, + { "iso9660", "iso9660", 32, 9, 5, "CDROM", 0x0, 0, 0 }, + { "jfs", "jfs", 32, 0, 4, "JFS1", 0x88, 0, 0 }, + { "swap", "swap", 0, 0x7ff6, 10, "SWAP-SPACE", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0x7ff6, 10, "SWAPSPACE2", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x7ff6, 9, "S1SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x7ff6, 9, "S2SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0x7ff6, 9, "ULSUSPEND", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0xfff6, 10, "SWAP-SPACE", 0x40c, 0, 0 }, + { "swap", "swap", 0, 0xfff6, 10, "SWAPSPACE2", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xfff6, 9, "S1SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xfff6, 9, "S2SUSPEND", 0x40c, 0, 0 }, + { "swap", "swsuspend", 0, 0xfff6, 9, "ULSUSPEND", 0x40c, 0, 0 }, + { "zfs", "zfs", 264, 0, 8, "\0\0\x02\xf5\xb0\x07\xb1\x0c", 0x0, 0, 0 }, + { "zfs", "zfs", 264, 0, 8, "\x0c\xb1\x07\xb0\xf5\x02\0\0", 0x0, 0, 0 }, + { NULL, NULL, 0, 0, 0, NULL, 0x0, 0, 0 } +}; + +static int null_uuid(const char *uuid) +{ + int i; + + for (i = 0; i < 16 && !uuid[i]; i++); + + return (i == 16); +} + + +static void uuid_end_bio(struct bio *bio) +{ + struct page *page = bio->bi_io_vec[0].bv_page; + + if (bio->bi_status == BLK_STS_IOERR) + SetPageError(page); + + unlock_page(page); + bio_put(bio); +} + + +/** + * read_bdev_page - Read a page from a device. + * @dev: The block device we're using. + * @page_num: The page we're reading. + * + * Based on Patrick Mochell's pmdisk code from long ago: "Straight from the + * textbook - allocate and initialize the bio. If we're writing, make sure + * the page is marked as dirty. Then submit it and carry on." + **/ +static struct page *read_bdev_page(struct block_device *dev, int page_num) +{ + struct bio *bio = NULL; + struct page *page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + + if (!page) { + printk(KERN_ERR "Failed to allocate a page for reading data " + "in UUID checks."); + return NULL; + } + + bio = bio_alloc(GFP_NOFS, 1); + bio->bi_bdev = dev; + bio->bi_iter.bi_sector = page_num << 3; + bio->bi_end_io = uuid_end_bio; + bio->bi_flags |= (1 << BIO_TOI); + + PRINTK("Submitting bio on device %lx, page %d using bio %p and page %p.\n", + (unsigned long) dev->bd_dev, page_num, bio, page); + + if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { + printk(KERN_DEBUG "ERROR: adding page to bio at %d\n", + page_num); + bio_put(bio); + __free_page(page); + printk(KERN_DEBUG "read_bdev_page freed page %p (in error " + "path).\n", page); + return NULL; + } + + lock_page(page); + bio_set_op_attrs(bio, REQ_OP_READ, REQ_SYNC); + submit_bio(bio); + + wait_on_page_locked(page); + if (PageError(page)) { + __free_page(page); + page = NULL; + } + return page; +} + +int bdev_matches_key(struct block_device *bdev, const char *key) +{ + unsigned char *data = NULL; + struct page *data_page = NULL; + + int dev_offset, pg_num, pg_off, i; + int last_pg_num = -1; + int result = 0; + char buf[50]; + + if (null_uuid(key)) { + PRINTK("Refusing to find a NULL key.\n"); + return 0; + } + + if (!bdev->bd_disk) { + bdevname(bdev, buf); + PRINTK("bdev %s has no bd_disk.\n", buf); + return 0; + } + + if (!bdev->bd_disk->queue) { + bdevname(bdev, buf); + PRINTK("bdev %s has no queue.\n", buf); + return 0; + } + + for (i = 0; uuid_list[i].name; i++) { + struct uuid_info *dat = &uuid_list[i]; + + if (!dat->key || strcmp(dat->key, key)) + continue; + + dev_offset = (dat->bkoff << 10) + dat->sboff; + pg_num = dev_offset >> 12; + pg_off = dev_offset & 0xfff; + + if ((((pg_num + 1) << 3) - 1) > bdev->bd_part->nr_sects >> 1) + continue; + + if (pg_num != last_pg_num) { + if (data_page) { + kunmap(data_page); + __free_page(data_page); + } + data_page = read_bdev_page(bdev, pg_num); + if (!data_page) + continue; + data = kmap(data_page); + } + + last_pg_num = pg_num; + + if (strncmp(&data[pg_off], dat->magic, dat->sig_len)) + continue; + + result = 1; + break; + } + + if (data_page) { + kunmap(data_page); + __free_page(data_page); + } + + return result; +} + +/* + * part_matches_fs_info - Does the given partition match the details given? + * + * Returns a score saying how good the match is. + * 0 = no UUID match. + * 1 = UUID but last mount time differs. + * 2 = UUID, last mount time but not dev_t + * 3 = perfect match + * + * This lets us cope elegantly with probing resulting in dev_ts changing + * from boot to boot, and with the case where a user copies a partition + * (UUID is non unique), and we need to check the last mount time of the + * correct partition. + */ +int part_matches_fs_info(struct hd_struct *part, struct fs_info *seek) +{ + struct block_device *bdev; + struct fs_info *got; + int result = 0; + char buf[50]; + + if (null_uuid((char *) &seek->uuid)) { + PRINTK("Refusing to find a NULL uuid.\n"); + return 0; + } + + bdev = bdget(part_devt(part)); + + PRINTK("part_matches fs info considering %x.\n", part_devt(part)); + + if (blkdev_get(bdev, FMODE_READ, 0)) { + PRINTK("blkdev_get failed.\n"); + return 0; + } + + if (!bdev->bd_disk) { + bdevname(bdev, buf); + PRINTK("bdev %s has no bd_disk.\n", buf); + goto out; + } + + if (!bdev->bd_disk->queue) { + bdevname(bdev, buf); + PRINTK("bdev %s has no queue.\n", buf); + goto out; + } + + got = fs_info_from_block_dev(bdev); + + if (got && !memcmp(got->uuid, seek->uuid, 16)) { + PRINTK(" Have matching UUID.\n"); + PRINTK(" Got: LMS %d, LM %p.\n", got->last_mount_size, got->last_mount); + PRINTK(" Seek: LMS %d, LM %p.\n", seek->last_mount_size, seek->last_mount); + result = 1; + + if (got->last_mount_size == seek->last_mount_size && + got->last_mount && seek->last_mount && + !memcmp(got->last_mount, seek->last_mount, + got->last_mount_size)) { + result = 2; + + PRINTK(" Matching last mount time.\n"); + + if (part_devt(part) == seek->dev_t) { + result = 3; + PRINTK(" Matching dev_t.\n"); + } else + PRINTK("Dev_ts differ (%x vs %x).\n", part_devt(part), seek->dev_t); + } + } + + PRINTK(" Score for %x is %d.\n", part_devt(part), result); + free_fs_info(got); +out: + blkdev_put(bdev, FMODE_READ); + return result; +} + +void free_fs_info(struct fs_info *fs_info) +{ + if (!fs_info || IS_ERR(fs_info)) + return; + + if (fs_info->last_mount) + kfree(fs_info->last_mount); + + kfree(fs_info); +} + +struct fs_info *fs_info_from_block_dev(struct block_device *bdev) +{ + unsigned char *data = NULL; + struct page *data_page = NULL; + + int dev_offset, pg_num, pg_off; + int uuid_pg_num, uuid_pg_off, i; + unsigned char *uuid_data = NULL; + struct page *uuid_data_page = NULL; + + int last_pg_num = -1, last_uuid_pg_num = 0; + char buf[50]; + struct fs_info *fs_info = NULL; + + bdevname(bdev, buf); + + PRINTK("uuid_from_block_dev looking for partition type of %s.\n", buf); + + for (i = 0; uuid_list[i].name; i++) { + struct uuid_info *dat = &uuid_list[i]; + dev_offset = (dat->bkoff << 10) + dat->sboff; + pg_num = dev_offset >> 12; + pg_off = dev_offset & 0xfff; + uuid_pg_num = dat->uuid_offset >> 12; + uuid_pg_off = dat->uuid_offset & 0xfff; + + if ((((pg_num + 1) << 3) - 1) > bdev->bd_part->nr_sects >> 1) + continue; + + /* Ignore partition types with no UUID offset */ + if (!dat->uuid_offset) + continue; + + if (pg_num != last_pg_num) { + if (data_page) { + kunmap(data_page); + __free_page(data_page); + } + data_page = read_bdev_page(bdev, pg_num); + if (!data_page) + continue; + data = kmap(data_page); + } + + last_pg_num = pg_num; + + if (strncmp(&data[pg_off], dat->magic, dat->sig_len)) + continue; + + PRINTK("This partition looks like %s.\n", dat->name); + + fs_info = kzalloc(sizeof(struct fs_info), GFP_KERNEL); + + if (!fs_info) { + PRINTK("Failed to allocate fs_info struct."); + fs_info = ERR_PTR(-ENOMEM); + break; + } + + /* UUID can't be off the end of the disk */ + if ((uuid_pg_num > bdev->bd_part->nr_sects >> 3) || + !dat->uuid_offset) + goto no_uuid; + + if (!uuid_data || uuid_pg_num != last_uuid_pg_num) { + /* No need to reread the page from above */ + if (uuid_pg_num == pg_num && uuid_data) + memcpy(uuid_data, data, PAGE_SIZE); + else { + if (uuid_data_page) { + kunmap(uuid_data_page); + __free_page(uuid_data_page); + } + uuid_data_page = read_bdev_page(bdev, uuid_pg_num); + if (!uuid_data_page) + continue; + uuid_data = kmap(uuid_data_page); + } + } + + last_uuid_pg_num = uuid_pg_num; + memcpy(&fs_info->uuid, &uuid_data[uuid_pg_off], 16); + fs_info->dev_t = bdev->bd_dev; + +no_uuid: + PRINT_HEX_DUMP(KERN_EMERG, "fs_info_from_block_dev " + "returning uuid ", DUMP_PREFIX_NONE, 16, 1, + fs_info->uuid, 16, 0); + + if (dat->last_mount_size) { + int pg = dat->last_mount_offset >> 12, sz; + int off = dat->last_mount_offset & 0xfff; + struct page *last_mount = read_bdev_page(bdev, pg); + unsigned char *last_mount_data; + char *ptr; + + if (!last_mount) { + fs_info = ERR_PTR(-ENOMEM); + break; + } + last_mount_data = kmap(last_mount); + sz = dat->last_mount_size; + ptr = kmalloc(sz, GFP_KERNEL); + + if (!ptr) { + printk(KERN_EMERG "fs_info_from_block_dev " + "failed to get memory for last mount " + "timestamp."); + free_fs_info(fs_info); + fs_info = ERR_PTR(-ENOMEM); + } else { + fs_info->last_mount = ptr; + fs_info->last_mount_size = sz; + memcpy(ptr, &last_mount_data[off], sz); + } + + kunmap(last_mount); + __free_page(last_mount); + } + break; + } + + if (data_page) { + kunmap(data_page); + __free_page(data_page); + } + + if (uuid_data_page) { + kunmap(uuid_data_page); + __free_page(uuid_data_page); + } + + return fs_info; +} + +static int __init uuid_debug_setup(char *str) +{ + int value; + + if (sscanf(str, "=%d", &value)) + debug_enabled = value; + + return 1; +} + +__setup("uuid_debug", uuid_debug_setup); diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f321b96..10707c3 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -700,6 +700,24 @@ static inline int is_loop_device(struct file *file) return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; } +/* + * for AUFS + * no get/put for file. + */ +struct file *loop_backing_file(struct super_block *sb) +{ + struct file *ret; + struct loop_device *l; + + ret = NULL; + if (MAJOR(sb->s_dev) == LOOP_MAJOR) { + l = sb->s_bdev->bd_disk->private_data; + ret = l->lo_backing_file; + } + return ret; +} +EXPORT_SYMBOL_GPL(loop_backing_file); + /* loop sysfs attributes */ static ssize_t loop_attr_show(struct device *dev, char *page, diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 3937acf..3d35d89 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -21,10 +21,18 @@ #include "cpufreq_ondemand.h" /* On-demand governor macros */ -#define DEF_FREQUENCY_UP_THRESHOLD (80) +#if defined(CONFIG_PCK_INTERACTIVE) && defined(CONFIG_SCHED_MUQSS) + #define DEF_FREQUENCY_UP_THRESHOLD (45) + #define MICRO_FREQUENCY_UP_THRESHOLD (45) +#elif defined(CONFIG_PCK_INTERACTIVE) + #define DEF_FREQUENCY_UP_THRESHOLD (80) + #define MICRO_FREQUENCY_UP_THRESHOLD (85) +#else + #define DEF_FREQUENCY_UP_THRESHOLD (80) + #define MICRO_FREQUENCY_UP_THRESHOLD (95) +#endif #define DEF_SAMPLING_DOWN_FACTOR (1) #define MAX_SAMPLING_DOWN_FACTOR (100000) -#define MICRO_FREQUENCY_UP_THRESHOLD (95) #define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000) #define MIN_FREQUENCY_UP_THRESHOLD (1) #define MAX_FREQUENCY_UP_THRESHOLD (100) diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c index 5af0b7d..f83df70 100644 --- a/drivers/input/mouse/synaptics.c +++ b/drivers/input/mouse/synaptics.c @@ -1315,7 +1315,9 @@ static void set_input_params(struct psmouse *psmouse, /* Clickpads report only left button */ __clear_bit(BTN_RIGHT, dev->keybit); __clear_bit(BTN_MIDDLE, dev->keybit); - } + } else if (SYN_CAP_CLICKPAD2BTN(info->ext_cap_0c) || + SYN_CAP_CLICKPAD2BTN2(info->ext_cap_0c)) + __set_bit(INPUT_PROP_BUTTONPAD, dev->propbit); } static ssize_t synaptics_show_disable_gesture(struct psmouse *psmouse, diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h index fc00e00..4cfbeec 100644 --- a/drivers/input/mouse/synaptics.h +++ b/drivers/input/mouse/synaptics.h @@ -86,6 +86,7 @@ */ #define SYN_CAP_CLICKPAD(ex0c) ((ex0c) & BIT(20)) /* 1-button ClickPad */ #define SYN_CAP_CLICKPAD2BTN(ex0c) ((ex0c) & BIT(8)) /* 2-button ClickPad */ +#define SYN_CAP_CLICKPAD2BTN2(ex0c) ((ex0c) & BIT(21)) /* 2-button ClickPad */ #define SYN_CAP_MAX_DIMENSIONS(ex0c) ((ex0c) & BIT(17)) #define SYN_CAP_MIN_DIMENSIONS(ex0c) ((ex0c) & BIT(13)) #define SYN_CAP_ADV_GESTURE(ex0c) ((ex0c) & BIT(19)) diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig index 97a420c..c8621e9 100644 --- a/drivers/macintosh/Kconfig +++ b/drivers/macintosh/Kconfig @@ -159,6 +159,13 @@ config INPUT_ADBHID If unsure, say Y. +config ADB_TRACKPAD_ABSOLUTE + bool "Enable absolute mode for adb trackpads" + depends on INPUT_ADBHID + help + Enable absolute mode in adb-base trackpads. This feature adds + compatibility with synaptics Xorg / Xfree drivers. + config MAC_EMUMOUSEBTN tristate "Support for mouse button 2+3 emulation" depends on SYSCTL && INPUT diff --git a/drivers/macintosh/adbhid.c b/drivers/macintosh/adbhid.c index 09d72bb..8d23b27 100644 --- a/drivers/macintosh/adbhid.c +++ b/drivers/macintosh/adbhid.c @@ -261,6 +261,15 @@ static struct adb_ids buttons_ids; #define ADBMOUSE_MS_A3 8 /* Mouse systems A3 trackball (handler 3) */ #define ADBMOUSE_MACALLY2 9 /* MacAlly 2-button mouse */ +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE +#define ABS_XMIN 310 +#define ABS_XMAX 1700 +#define ABS_YMIN 200 +#define ABS_YMAX 1000 +#define ABS_ZMIN 0 +#define ABS_ZMAX 55 +#endif + static void adbhid_keyboard_input(unsigned char *data, int nb, int apoll) { @@ -405,6 +414,9 @@ static void adbhid_mouse_input(unsigned char *data, int nb, int autopoll) { int id = (data[0] >> 4) & 0x0f; +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + int btn = 0; int x_axis = 0; int y_axis = 0; int z_axis = 0; +#endif if (!adbhid[id]) { printk(KERN_ERR "ADB HID on ID %d not yet registered\n", id); @@ -436,6 +448,17 @@ adbhid_mouse_input(unsigned char *data, int nb, int autopoll) high bits of y-axis motion. XY is additional high bits of x-axis motion. + For ADB Absolute motion protocol the data array will contain the + following values: + + BITS COMMENTS + data[0] = dddd 1100 ADB command: Talk, register 0, for device dddd. + data[1] = byyy yyyy Left button and y-axis motion. + data[2] = bxxx xxxx Second button and x-axis motion. + data[3] = 1yyy 1xxx Half bits of y-axis and x-axis motion. + data[4] = 1yyy 1xxx Higher bits of y-axis and x-axis motion. + data[5] = 1zzz 1zzz Higher and lower bits of z-pressure. + MacAlly 2-button mouse protocol. For MacAlly 2-button mouse protocol the data array will contain the @@ -458,8 +481,17 @@ adbhid_mouse_input(unsigned char *data, int nb, int autopoll) switch (adbhid[id]->mouse_kind) { case ADBMOUSE_TRACKPAD: +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + x_axis = (data[2] & 0x7f) | ((data[3] & 0x07) << 7) | + ((data[4] & 0x07) << 10); + y_axis = (data[1] & 0x7f) | ((data[3] & 0x70) << 3) | + ((data[4] & 0x70) << 6); + z_axis = (data[5] & 0x07) | ((data[5] & 0x70) >> 1); + btn = (!(data[1] >> 7)) & 1; +#else data[1] = (data[1] & 0x7f) | ((data[1] & data[2]) & 0x80); data[2] = data[2] | 0x80; +#endif break; case ADBMOUSE_MICROSPEED: data[1] = (data[1] & 0x7f) | ((data[3] & 0x01) << 7); @@ -485,17 +517,39 @@ adbhid_mouse_input(unsigned char *data, int nb, int autopoll) break; } - input_report_key(adbhid[id]->input, BTN_LEFT, !((data[1] >> 7) & 1)); - input_report_key(adbhid[id]->input, BTN_MIDDLE, !((data[2] >> 7) & 1)); +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + if ( adbhid[id]->mouse_kind == ADBMOUSE_TRACKPAD ) { - if (nb >= 4 && adbhid[id]->mouse_kind != ADBMOUSE_TRACKPAD) - input_report_key(adbhid[id]->input, BTN_RIGHT, !((data[3] >> 7) & 1)); + if(z_axis > 30) input_report_key(adbhid[id]->input, BTN_TOUCH, 1); + if(z_axis < 25) input_report_key(adbhid[id]->input, BTN_TOUCH, 0); - input_report_rel(adbhid[id]->input, REL_X, - ((data[2]&0x7f) < 64 ? (data[2]&0x7f) : (data[2]&0x7f)-128 )); - input_report_rel(adbhid[id]->input, REL_Y, - ((data[1]&0x7f) < 64 ? (data[1]&0x7f) : (data[1]&0x7f)-128 )); + if(z_axis > 0){ + input_report_abs(adbhid[id]->input, ABS_X, x_axis); + input_report_abs(adbhid[id]->input, ABS_Y, y_axis); + input_report_key(adbhid[id]->input, BTN_TOOL_FINGER, 1); + input_report_key(adbhid[id]->input, ABS_TOOL_WIDTH, 5); + } else { + input_report_key(adbhid[id]->input, BTN_TOOL_FINGER, 0); + input_report_key(adbhid[id]->input, ABS_TOOL_WIDTH, 0); + } + + input_report_abs(adbhid[id]->input, ABS_PRESSURE, z_axis); + input_report_key(adbhid[id]->input, BTN_LEFT, btn); + } else { +#endif + input_report_key(adbhid[id]->input, BTN_LEFT, !((data[1] >> 7) & 1)); + input_report_key(adbhid[id]->input, BTN_MIDDLE, !((data[2] >> 7) & 1)); + + if (nb >= 4 && adbhid[id]->mouse_kind != ADBMOUSE_TRACKPAD) + input_report_key(adbhid[id]->input, BTN_RIGHT, !((data[3] >> 7) & 1)); + input_report_rel(adbhid[id]->input, REL_X, + ((data[2]&0x7f) < 64 ? (data[2]&0x7f) : (data[2]&0x7f)-128 )); + input_report_rel(adbhid[id]->input, REL_Y, + ((data[1]&0x7f) < 64 ? (data[1]&0x7f) : (data[1]&0x7f)-128 )); +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + } +#endif input_sync(adbhid[id]->input); } @@ -849,6 +903,15 @@ adbhid_input_register(int id, int default_id, int original_handler_id, input_dev->keybit[BIT_WORD(BTN_MOUSE)] = BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT); input_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y); +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + set_bit(EV_ABS, input_dev->evbit); + input_set_abs_params(input_dev, ABS_X, ABS_XMIN, ABS_XMAX, 0, 0); + input_set_abs_params(input_dev, ABS_Y, ABS_YMIN, ABS_YMAX, 0, 0); + input_set_abs_params(input_dev, ABS_PRESSURE, ABS_ZMIN, ABS_ZMAX, 0, 0); + set_bit(BTN_TOUCH, input_dev->keybit); + set_bit(BTN_TOOL_FINGER, input_dev->keybit); + set_bit(ABS_TOOL_WIDTH, input_dev->absbit); +#endif break; case ADB_MISC: @@ -1132,7 +1195,11 @@ init_trackpad(int id) r1_buffer[3], r1_buffer[4], r1_buffer[5], +#ifdef CONFIG_ADB_TRACKPAD_ABSOLUTE + 0x00, /* Enable absolute mode */ +#else 0x03, /*r1_buffer[6],*/ +#endif r1_buffer[7]); /* Without this flush, the trackpad may be locked up */ diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 80b8795..6685d38 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -511,9 +511,28 @@ config THINKPAD_ACPI_HOTKEY_POLL If you are not sure, say Y here. The driver enables polling only if it is strictly necessary to do so. +config THINKPAD_EC + tristate + ---help--- + This is a low-level driver for accessing the ThinkPad H8S embedded + controller over the LPC bus (not to be confused with the ACPI Embedded + Controller interface). + +config TP_SMAPI + tristate "ThinkPad SMAPI Support" + select THINKPAD_EC + default n + help + This adds SMAPI support on Lenovo/IBM ThinkPads, for features such + as battery charging control. For more information about this driver + see . + + If you have a Lenovo/IBM ThinkPad laptop, say Y or M here. + config SENSORS_HDAPS tristate "Thinkpad Hard Drive Active Protection System (hdaps)" depends on INPUT + select THINKPAD_EC select INPUT_POLLDEV default n help diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile index 91cec17..d0f6e81 100644 --- a/drivers/platform/x86/Makefile +++ b/drivers/platform/x86/Makefile @@ -28,6 +28,8 @@ obj-$(CONFIG_TC1100_WMI) += tc1100-wmi.o obj-$(CONFIG_SONY_LAPTOP) += sony-laptop.o obj-$(CONFIG_IDEAPAD_LAPTOP) += ideapad-laptop.o obj-$(CONFIG_THINKPAD_ACPI) += thinkpad_acpi.o +obj-$(CONFIG_THINKPAD_EC) += thinkpad_ec.o +obj-$(CONFIG_TP_SMAPI) += tp_smapi.o obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o obj-$(CONFIG_FUJITSU_LAPTOP) += fujitsu-laptop.o obj-$(CONFIG_FUJITSU_TABLET) += fujitsu-tablet.o diff --git a/drivers/platform/x86/hdaps.c b/drivers/platform/x86/hdaps.c index 458e6c9..dadfb99 100644 --- a/drivers/platform/x86/hdaps.c +++ b/drivers/platform/x86/hdaps.c @@ -30,266 +30,384 @@ #include #include -#include +#include #include -#include #include #include #include #include -#include - -#define HDAPS_LOW_PORT 0x1600 /* first port used by hdaps */ -#define HDAPS_NR_PORTS 0x30 /* number of ports: 0x1600 - 0x162f */ - -#define HDAPS_PORT_STATE 0x1611 /* device state */ -#define HDAPS_PORT_YPOS 0x1612 /* y-axis position */ -#define HDAPS_PORT_XPOS 0x1614 /* x-axis position */ -#define HDAPS_PORT_TEMP1 0x1616 /* device temperature, in Celsius */ -#define HDAPS_PORT_YVAR 0x1617 /* y-axis variance (what is this?) */ -#define HDAPS_PORT_XVAR 0x1619 /* x-axis variance (what is this?) */ -#define HDAPS_PORT_TEMP2 0x161b /* device temperature (again?) */ -#define HDAPS_PORT_UNKNOWN 0x161c /* what is this? */ -#define HDAPS_PORT_KMACT 0x161d /* keyboard or mouse activity */ - -#define STATE_FRESH 0x50 /* accelerometer data is fresh */ +#include +#include +#include + +/* Embedded controller accelerometer read command and its result: */ +static const struct thinkpad_ec_row ec_accel_args = + { .mask = 0x0001, .val = {0x11} }; +#define EC_ACCEL_IDX_READOUTS 0x1 /* readouts included in this read */ + /* First readout, if READOUTS>=1: */ +#define EC_ACCEL_IDX_YPOS1 0x2 /* y-axis position word */ +#define EC_ACCEL_IDX_XPOS1 0x4 /* x-axis position word */ +#define EC_ACCEL_IDX_TEMP1 0x6 /* device temperature in Celsius */ + /* Second readout, if READOUTS>=2: */ +#define EC_ACCEL_IDX_XPOS2 0x7 /* y-axis position word */ +#define EC_ACCEL_IDX_YPOS2 0x9 /* x-axis position word */ +#define EC_ACCEL_IDX_TEMP2 0xb /* device temperature in Celsius */ +#define EC_ACCEL_IDX_QUEUED 0xc /* Number of queued readouts left */ +#define EC_ACCEL_IDX_KMACT 0xd /* keyboard or mouse activity */ +#define EC_ACCEL_IDX_RETVAL 0xf /* command return value, good=0x00 */ #define KEYBD_MASK 0x20 /* set if keyboard activity */ #define MOUSE_MASK 0x40 /* set if mouse activity */ -#define KEYBD_ISSET(n) (!! (n & KEYBD_MASK)) /* keyboard used? */ -#define MOUSE_ISSET(n) (!! (n & MOUSE_MASK)) /* mouse used? */ -#define INIT_TIMEOUT_MSECS 4000 /* wait up to 4s for device init ... */ -#define INIT_WAIT_MSECS 200 /* ... in 200ms increments */ +#define READ_TIMEOUT_MSECS 100 /* wait this long for device read */ +#define RETRY_MSECS 3 /* retry delay */ -#define HDAPS_POLL_INTERVAL 50 /* poll for input every 1/20s (50 ms)*/ #define HDAPS_INPUT_FUZZ 4 /* input event threshold */ #define HDAPS_INPUT_FLAT 4 - -#define HDAPS_X_AXIS (1 << 0) -#define HDAPS_Y_AXIS (1 << 1) -#define HDAPS_BOTH_AXES (HDAPS_X_AXIS | HDAPS_Y_AXIS) - +#define KMACT_REMEMBER_PERIOD (HZ/10) /* keyboard/mouse persistance */ + +/* Input IDs */ +#define HDAPS_INPUT_VENDOR PCI_VENDOR_ID_IBM +#define HDAPS_INPUT_PRODUCT 0x5054 /* "TP", shared with thinkpad_acpi */ +#define HDAPS_INPUT_JS_VERSION 0x6801 /* Joystick emulation input device */ +#define HDAPS_INPUT_RAW_VERSION 0x4801 /* Raw accelerometer input device */ + +/* Axis orientation. */ +/* The unnatural bit-representation of inversions is for backward + * compatibility with the"invert=1" module parameter. */ +#define HDAPS_ORIENT_INVERT_XY 0x01 /* Invert both X and Y axes. */ +#define HDAPS_ORIENT_INVERT_X 0x02 /* Invert the X axis (uninvert if + * already inverted by INVERT_XY). */ +#define HDAPS_ORIENT_SWAP 0x04 /* Swap the axes. The swap occurs + * before inverting X or Y. */ +#define HDAPS_ORIENT_MAX 0x07 +#define HDAPS_ORIENT_UNDEFINED 0xFF /* Placeholder during initialization */ +#define HDAPS_ORIENT_INVERT_Y (HDAPS_ORIENT_INVERT_XY | HDAPS_ORIENT_INVERT_X) + +static struct timer_list hdaps_timer; static struct platform_device *pdev; -static struct input_polled_dev *hdaps_idev; -static unsigned int hdaps_invert; -static u8 km_activity; -static int rest_x; -static int rest_y; - -static DEFINE_MUTEX(hdaps_mtx); - -/* - * __get_latch - Get the value from a given port. Callers must hold hdaps_mtx. - */ -static inline u8 __get_latch(u16 port) +static struct input_dev *hdaps_idev; /* joystick-like device with fuzz */ +static struct input_dev *hdaps_idev_raw; /* raw hdaps sensor readouts */ +static unsigned int hdaps_invert = HDAPS_ORIENT_UNDEFINED; +static int needs_calibration; + +/* Configuration: */ +static int sampling_rate = 50; /* Sampling rate */ +static int oversampling_ratio = 5; /* Ratio between our sampling rate and + * EC accelerometer sampling rate */ +static int running_avg_filter_order = 2; /* EC running average filter order */ + +/* Latest state readout: */ +static int pos_x, pos_y; /* position */ +static int temperature; /* temperature */ +static int stale_readout = 1; /* last read invalid */ +static int rest_x, rest_y; /* calibrated rest position */ + +/* Last time we saw keyboard and mouse activity: */ +static u64 last_keyboard_jiffies = INITIAL_JIFFIES; +static u64 last_mouse_jiffies = INITIAL_JIFFIES; +static u64 last_update_jiffies = INITIAL_JIFFIES; + +/* input device use count */ +static int hdaps_users; +static DEFINE_MUTEX(hdaps_users_mtx); + +/* Some models require an axis transformation to the standard representation */ +static void transform_axes(int *x, int *y) { - return inb(port) & 0xff; + if (hdaps_invert & HDAPS_ORIENT_SWAP) { + int z; + z = *x; + *x = *y; + *y = z; + } + if (hdaps_invert & HDAPS_ORIENT_INVERT_XY) { + *x = -*x; + *y = -*y; + } + if (hdaps_invert & HDAPS_ORIENT_INVERT_X) + *x = -*x; } -/* - * __check_latch - Check a port latch for a given value. Returns zero if the - * port contains the given value. Callers must hold hdaps_mtx. +/** + * __hdaps_update - query current state, with locks already acquired + * @fast: if nonzero, do one quick attempt without retries. + * + * Query current accelerometer state and update global state variables. + * Also prefetches the next query. Caller must hold controller lock. */ -static inline int __check_latch(u16 port, u8 val) +static int __hdaps_update(int fast) { - if (__get_latch(port) == val) - return 0; - return -EINVAL; -} + /* Read data: */ + struct thinkpad_ec_row data; + int ret; -/* - * __wait_latch - Wait up to 100us for a port latch to get a certain value, - * returning zero if the value is obtained. Callers must hold hdaps_mtx. - */ -static int __wait_latch(u16 port, u8 val) -{ - unsigned int i; + data.mask = (1 << EC_ACCEL_IDX_READOUTS) | (1 << EC_ACCEL_IDX_KMACT) | + (3 << EC_ACCEL_IDX_YPOS1) | (3 << EC_ACCEL_IDX_XPOS1) | + (1 << EC_ACCEL_IDX_TEMP1) | (1 << EC_ACCEL_IDX_RETVAL); + if (fast) + ret = thinkpad_ec_try_read_row(&ec_accel_args, &data); + else + ret = thinkpad_ec_read_row(&ec_accel_args, &data); + thinkpad_ec_prefetch_row(&ec_accel_args); /* Prefetch even if error */ + if (ret) + return ret; - for (i = 0; i < 20; i++) { - if (!__check_latch(port, val)) - return 0; - udelay(5); + /* Check status: */ + if (data.val[EC_ACCEL_IDX_RETVAL] != 0x00) { + pr_warn("read RETVAL=0x%02x\n", + data.val[EC_ACCEL_IDX_RETVAL]); + return -EIO; + } + + if (data.val[EC_ACCEL_IDX_READOUTS] < 1) + return -EBUSY; /* no pending readout, try again later */ + + /* Parse position data: */ + pos_x = *(s16 *)(data.val+EC_ACCEL_IDX_XPOS1); + pos_y = *(s16 *)(data.val+EC_ACCEL_IDX_YPOS1); + transform_axes(&pos_x, &pos_y); + + /* Keyboard and mouse activity status is cleared as soon as it's read, + * so applications will eat each other's events. Thus we remember any + * event for KMACT_REMEMBER_PERIOD jiffies. + */ + if (data.val[EC_ACCEL_IDX_KMACT] & KEYBD_MASK) + last_keyboard_jiffies = get_jiffies_64(); + if (data.val[EC_ACCEL_IDX_KMACT] & MOUSE_MASK) + last_mouse_jiffies = get_jiffies_64(); + + temperature = data.val[EC_ACCEL_IDX_TEMP1]; + + last_update_jiffies = get_jiffies_64(); + stale_readout = 0; + if (needs_calibration) { + rest_x = pos_x; + rest_y = pos_y; + needs_calibration = 0; } - return -EIO; + return 0; } -/* - * __device_refresh - request a refresh from the accelerometer. Does not wait - * for refresh to complete. Callers must hold hdaps_mtx. +/** + * hdaps_update - acquire locks and query current state + * + * Query current accelerometer state and update global state variables. + * Also prefetches the next query. + * Retries until timeout if the accelerometer is not in ready status (common). + * Does its own locking. */ -static void __device_refresh(void) +static int hdaps_update(void) { - udelay(200); - if (inb(0x1604) != STATE_FRESH) { - outb(0x11, 0x1610); - outb(0x01, 0x161f); + u64 age = get_jiffies_64() - last_update_jiffies; + int total, ret; + + if (!stale_readout && age < (9*HZ)/(10*sampling_rate)) + return 0; /* already updated recently */ + for (total = 0; total < READ_TIMEOUT_MSECS; total += RETRY_MSECS) { + ret = thinkpad_ec_lock(); + if (ret) + return ret; + ret = __hdaps_update(0); + thinkpad_ec_unlock(); + + if (!ret) + return 0; + if (ret != -EBUSY) + break; + msleep(RETRY_MSECS); } + return ret; } -/* - * __device_refresh_sync - request a synchronous refresh from the - * accelerometer. We wait for the refresh to complete. Returns zero if - * successful and nonzero on error. Callers must hold hdaps_mtx. +/** + * hdaps_set_power - enable or disable power to the accelerometer. + * Returns zero on success and negative error code on failure. Can sleep. */ -static int __device_refresh_sync(void) +static int hdaps_set_power(int on) { - __device_refresh(); - return __wait_latch(0x1604, STATE_FRESH); + struct thinkpad_ec_row args = + { .mask = 0x0003, .val = {0x14, on?0x01:0x00} }; + struct thinkpad_ec_row data = { .mask = 0x8000 }; + int ret = thinkpad_ec_read_row(&args, &data); + if (ret) + return ret; + if (data.val[0xF] != 0x00) + return -EIO; + return 0; } -/* - * __device_complete - indicate to the accelerometer that we are done reading - * data, and then initiate an async refresh. Callers must hold hdaps_mtx. +/** + * hdaps_set_ec_config - set accelerometer parameters. + * @ec_rate: embedded controller sampling rate + * @order: embedded controller running average filter order + * (Normally we have @ec_rate = sampling_rate * oversampling_ratio.) + * Returns zero on success and negative error code on failure. Can sleep. */ -static inline void __device_complete(void) +static int hdaps_set_ec_config(int ec_rate, int order) { - inb(0x161f); - inb(0x1604); - __device_refresh(); + struct thinkpad_ec_row args = { .mask = 0x000F, + .val = {0x10, (u8)ec_rate, (u8)(ec_rate>>8), order} }; + struct thinkpad_ec_row data = { .mask = 0x8000 }; + int ret = thinkpad_ec_read_row(&args, &data); + pr_debug("setting ec_rate=%d, filter_order=%d\n", ec_rate, order); + if (ret) + return ret; + if (data.val[0xF] == 0x03) { + pr_warn("config param out of range\n"); + return -EINVAL; + } + if (data.val[0xF] == 0x06) { + pr_warn("config change already pending\n"); + return -EBUSY; + } + if (data.val[0xF] != 0x00) { + pr_warn("config change error, ret=%d\n", + data.val[0xF]); + return -EIO; + } + return 0; } -/* - * hdaps_readb_one - reads a byte from a single I/O port, placing the value in - * the given pointer. Returns zero on success or a negative error on failure. - * Can sleep. +/** + * hdaps_get_ec_config - get accelerometer parameters. + * @ec_rate: embedded controller sampling rate + * @order: embedded controller running average filter order + * Returns zero on success and negative error code on failure. Can sleep. */ -static int hdaps_readb_one(unsigned int port, u8 *val) +static int hdaps_get_ec_config(int *ec_rate, int *order) { - int ret; - - mutex_lock(&hdaps_mtx); - - /* do a sync refresh -- we need to be sure that we read fresh data */ - ret = __device_refresh_sync(); + const struct thinkpad_ec_row args = + { .mask = 0x0003, .val = {0x17, 0x82} }; + struct thinkpad_ec_row data = { .mask = 0x801F }; + int ret = thinkpad_ec_read_row(&args, &data); if (ret) - goto out; - - *val = inb(port); - __device_complete(); - -out: - mutex_unlock(&hdaps_mtx); - return ret; + return ret; + if (data.val[0xF] != 0x00) + return -EIO; + if (!(data.val[0x1] & 0x01)) + return -ENXIO; /* accelerometer polling not enabled */ + if (data.val[0x1] & 0x02) + return -EBUSY; /* config change in progress, retry later */ + *ec_rate = data.val[0x2] | ((int)(data.val[0x3]) << 8); + *order = data.val[0x4]; + return 0; } -/* __hdaps_read_pair - internal lockless helper for hdaps_read_pair(). */ -static int __hdaps_read_pair(unsigned int port1, unsigned int port2, - int *x, int *y) +/** + * hdaps_get_ec_mode - get EC accelerometer mode + * Returns zero on success and negative error code on failure. Can sleep. + */ +static int hdaps_get_ec_mode(u8 *mode) { - /* do a sync refresh -- we need to be sure that we read fresh data */ - if (__device_refresh_sync()) + const struct thinkpad_ec_row args = + { .mask = 0x0001, .val = {0x13} }; + struct thinkpad_ec_row data = { .mask = 0x8002 }; + int ret = thinkpad_ec_read_row(&args, &data); + if (ret) + return ret; + if (data.val[0xF] != 0x00) { + pr_warn("accelerometer not implemented (0x%02x)\n", + data.val[0xF]); return -EIO; - - *y = inw(port2); - *x = inw(port1); - km_activity = inb(HDAPS_PORT_KMACT); - __device_complete(); - - /* hdaps_invert is a bitvector to negate the axes */ - if (hdaps_invert & HDAPS_X_AXIS) - *x = -*x; - if (hdaps_invert & HDAPS_Y_AXIS) - *y = -*y; - + } + *mode = data.val[0x1]; return 0; } -/* - * hdaps_read_pair - reads the values from a pair of ports, placing the values - * in the given pointers. Returns zero on success. Can sleep. +/** + * hdaps_check_ec - checks something about the EC. + * Follows the clean-room spec for HDAPS; we don't know what it means. + * Returns zero on success and negative error code on failure. Can sleep. */ -static int hdaps_read_pair(unsigned int port1, unsigned int port2, - int *val1, int *val2) +static int hdaps_check_ec(void) { - int ret; - - mutex_lock(&hdaps_mtx); - ret = __hdaps_read_pair(port1, port2, val1, val2); - mutex_unlock(&hdaps_mtx); - - return ret; + const struct thinkpad_ec_row args = + { .mask = 0x0003, .val = {0x17, 0x81} }; + struct thinkpad_ec_row data = { .mask = 0x800E }; + int ret = thinkpad_ec_read_row(&args, &data); + if (ret) + return ret; + if (!((data.val[0x1] == 0x00 && data.val[0x2] == 0x60) || /* cleanroom spec */ + (data.val[0x1] == 0x01 && data.val[0x2] == 0x00)) || /* seen on T61 */ + data.val[0x3] != 0x00 || data.val[0xF] != 0x00) { + pr_warn("hdaps_check_ec: bad response (0x%x,0x%x,0x%x,0x%x)\n", + data.val[0x1], data.val[0x2], + data.val[0x3], data.val[0xF]); + return -EIO; + } + return 0; } -/* - * hdaps_device_init - initialize the accelerometer. Returns zero on success - * and negative error code on failure. Can sleep. +/** + * hdaps_device_init - initialize the accelerometer. + * + * Call several embedded controller functions to test and initialize the + * accelerometer. + * Returns zero on success and negative error code on failure. Can sleep. */ +#define FAILED_INIT(msg) pr_err("init failed at: %s\n", msg) static int hdaps_device_init(void) { - int total, ret = -ENXIO; + int ret; + u8 mode; - mutex_lock(&hdaps_mtx); + ret = thinkpad_ec_lock(); + if (ret) + return ret; - outb(0x13, 0x1610); - outb(0x01, 0x161f); - if (__wait_latch(0x161f, 0x00)) - goto out; + if (hdaps_get_ec_mode(&mode)) + { FAILED_INIT("hdaps_get_ec_mode failed"); goto bad; } - /* - * Most ThinkPads return 0x01. - * - * Others--namely the R50p, T41p, and T42p--return 0x03. These laptops - * have "inverted" axises. - * - * The 0x02 value occurs when the chip has been previously initialized. - */ - if (__check_latch(0x1611, 0x03) && - __check_latch(0x1611, 0x02) && - __check_latch(0x1611, 0x01)) - goto out; - - printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x)\n", - __get_latch(0x1611)); + pr_debug("initial mode latch is 0x%02x\n", mode); + if (mode == 0x00) + { FAILED_INIT("accelerometer not available"); goto bad; } - outb(0x17, 0x1610); - outb(0x81, 0x1611); - outb(0x01, 0x161f); - if (__wait_latch(0x161f, 0x00)) - goto out; - if (__wait_latch(0x1611, 0x00)) - goto out; - if (__wait_latch(0x1612, 0x60)) - goto out; - if (__wait_latch(0x1613, 0x00)) - goto out; - outb(0x14, 0x1610); - outb(0x01, 0x1611); - outb(0x01, 0x161f); - if (__wait_latch(0x161f, 0x00)) - goto out; - outb(0x10, 0x1610); - outb(0xc8, 0x1611); - outb(0x00, 0x1612); - outb(0x02, 0x1613); - outb(0x01, 0x161f); - if (__wait_latch(0x161f, 0x00)) - goto out; - if (__device_refresh_sync()) - goto out; - if (__wait_latch(0x1611, 0x00)) - goto out; + if (hdaps_check_ec()) + { FAILED_INIT("hdaps_check_ec failed"); goto bad; } - /* we have done our dance, now let's wait for the applause */ - for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) { - int x, y; + if (hdaps_set_power(1)) + { FAILED_INIT("hdaps_set_power failed"); goto bad; } - /* a read of the device helps push it into action */ - __hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y); - if (!__wait_latch(0x1611, 0x02)) { - ret = 0; - break; - } + if (hdaps_set_ec_config(sampling_rate*oversampling_ratio, + running_avg_filter_order)) + { FAILED_INIT("hdaps_set_ec_config failed"); goto bad; } - msleep(INIT_WAIT_MSECS); - } + thinkpad_ec_invalidate(); + udelay(200); -out: - mutex_unlock(&hdaps_mtx); + /* Just prefetch instead of reading, to avoid ~1sec delay on load */ + ret = thinkpad_ec_prefetch_row(&ec_accel_args); + if (ret) + { FAILED_INIT("initial prefetch failed"); goto bad; } + goto good; +bad: + thinkpad_ec_invalidate(); + ret = -ENXIO; +good: + stale_readout = 1; + thinkpad_ec_unlock(); return ret; } +/** + * hdaps_device_shutdown - power off the accelerometer + * Returns nonzero on failure. Can sleep. + */ +static int hdaps_device_shutdown(void) +{ + int ret; + ret = hdaps_set_power(0); + if (ret) { + pr_warn("cannot power off\n"); + return ret; + } + ret = hdaps_set_ec_config(0, 1); + if (ret) + pr_warn("cannot stop EC sampling\n"); + return ret; +} /* Device model stuff */ @@ -306,13 +424,29 @@ static int hdaps_probe(struct platform_device *dev) } #ifdef CONFIG_PM_SLEEP +static int hdaps_suspend(struct device *dev) +{ + /* Don't do hdaps polls until resume re-initializes the sensor. */ + del_timer_sync(&hdaps_timer); + hdaps_device_shutdown(); /* ignore errors, effect is negligible */ + return 0; +} + static int hdaps_resume(struct device *dev) { - return hdaps_device_init(); + int ret = hdaps_device_init(); + if (ret) + return ret; + + mutex_lock(&hdaps_users_mtx); + if (hdaps_users) + mod_timer(&hdaps_timer, jiffies + HZ/sampling_rate); + mutex_unlock(&hdaps_users_mtx); + return 0; } #endif -static SIMPLE_DEV_PM_OPS(hdaps_pm, NULL, hdaps_resume); +static SIMPLE_DEV_PM_OPS(hdaps_pm, hdaps_suspend, hdaps_resume); static struct platform_driver hdaps_driver = { .probe = hdaps_probe, @@ -322,30 +456,47 @@ static struct platform_driver hdaps_driver = { }, }; -/* - * hdaps_calibrate - Set our "resting" values. Callers must hold hdaps_mtx. +/** + * hdaps_calibrate - set our "resting" values. + * Does its own locking. */ static void hdaps_calibrate(void) { - __hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y); + needs_calibration = 1; + hdaps_update(); + /* If that fails, the mousedev poll will take care of things later. */ } -static void hdaps_mousedev_poll(struct input_polled_dev *dev) +/* Timer handler for updating the input device. Runs in softirq context, + * so avoid lenghty or blocking operations. + */ +static void hdaps_mousedev_poll(unsigned long unused) { - struct input_dev *input_dev = dev->input; - int x, y; + int ret; - mutex_lock(&hdaps_mtx); + stale_readout = 1; - if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y)) - goto out; + /* Cannot sleep. Try nonblockingly. If we fail, try again later. */ + if (thinkpad_ec_try_lock()) + goto keep_active; - input_report_abs(input_dev, ABS_X, x - rest_x); - input_report_abs(input_dev, ABS_Y, y - rest_y); - input_sync(input_dev); + ret = __hdaps_update(1); /* fast update, we're in softirq context */ + thinkpad_ec_unlock(); + /* Any of "successful", "not yet ready" and "not prefetched"? */ + if (ret != 0 && ret != -EBUSY && ret != -ENODATA) { + pr_err("poll failed, disabling updates\n"); + return; + } -out: - mutex_unlock(&hdaps_mtx); +keep_active: + /* Even if we failed now, pos_x,y may have been updated earlier: */ + input_report_abs(hdaps_idev, ABS_X, pos_x - rest_x); + input_report_abs(hdaps_idev, ABS_Y, pos_y - rest_y); + input_sync(hdaps_idev); + input_report_abs(hdaps_idev_raw, ABS_X, pos_x); + input_report_abs(hdaps_idev_raw, ABS_Y, pos_y); + input_sync(hdaps_idev_raw); + mod_timer(&hdaps_timer, jiffies + HZ/sampling_rate); } @@ -354,65 +505,41 @@ out: static ssize_t hdaps_position_show(struct device *dev, struct device_attribute *attr, char *buf) { - int ret, x, y; - - ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y); - if (ret) - return ret; - - return sprintf(buf, "(%d,%d)\n", x, y); -} - -static ssize_t hdaps_variance_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - int ret, x, y; - - ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y); + int ret = hdaps_update(); if (ret) return ret; - - return sprintf(buf, "(%d,%d)\n", x, y); + return sprintf(buf, "(%d,%d)\n", pos_x, pos_y); } static ssize_t hdaps_temp1_show(struct device *dev, struct device_attribute *attr, char *buf) { - u8 uninitialized_var(temp); - int ret; - - ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp); - if (ret) - return ret; - - return sprintf(buf, "%u\n", temp); -} - -static ssize_t hdaps_temp2_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - u8 uninitialized_var(temp); - int ret; - - ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp); + int ret = hdaps_update(); if (ret) return ret; - - return sprintf(buf, "%u\n", temp); + return sprintf(buf, "%d\n", temperature); } static ssize_t hdaps_keyboard_activity_show(struct device *dev, struct device_attribute *attr, char *buf) { - return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity)); + int ret = hdaps_update(); + if (ret) + return ret; + return sprintf(buf, "%u\n", + get_jiffies_64() < last_keyboard_jiffies + KMACT_REMEMBER_PERIOD); } static ssize_t hdaps_mouse_activity_show(struct device *dev, struct device_attribute *attr, char *buf) { - return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity)); + int ret = hdaps_update(); + if (ret) + return ret; + return sprintf(buf, "%u\n", + get_jiffies_64() < last_mouse_jiffies + KMACT_REMEMBER_PERIOD); } static ssize_t hdaps_calibrate_show(struct device *dev, @@ -425,10 +552,7 @@ static ssize_t hdaps_calibrate_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - mutex_lock(&hdaps_mtx); hdaps_calibrate(); - mutex_unlock(&hdaps_mtx); - return count; } @@ -445,7 +569,7 @@ static ssize_t hdaps_invert_store(struct device *dev, int invert; if (sscanf(buf, "%d", &invert) != 1 || - invert < 0 || invert > HDAPS_BOTH_AXES) + invert < 0 || invert > HDAPS_ORIENT_MAX) return -EINVAL; hdaps_invert = invert; @@ -454,24 +578,128 @@ static ssize_t hdaps_invert_store(struct device *dev, return count; } +static ssize_t hdaps_sampling_rate_show( + struct device *dev, struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", sampling_rate); +} + +static ssize_t hdaps_sampling_rate_store( + struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int rate, ret; + if (sscanf(buf, "%d", &rate) != 1 || rate > HZ || rate <= 0) { + pr_warn("must have 0ident); - return 1; -} - /* hdaps_dmi_match_invert - found an inverted match. */ static int __init hdaps_dmi_match_invert(const struct dmi_system_id *id) { - hdaps_invert = (unsigned long)id->driver_data; - pr_info("inverting axis (%u) readings\n", hdaps_invert); - return hdaps_dmi_match(id); + unsigned int orient = (kernel_ulong_t) id->driver_data; + hdaps_invert = orient; + pr_info("%s detected, setting orientation %u\n", id->ident, orient); + return 1; /* stop enumeration */ } -#define HDAPS_DMI_MATCH_INVERT(vendor, model, axes) { \ +#define HDAPS_DMI_MATCH_INVERT(vendor, model, orient) { \ .ident = vendor " " model, \ .callback = hdaps_dmi_match_invert, \ - .driver_data = (void *)axes, \ + .driver_data = (void *)(orient), \ .matches = { \ DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ DMI_MATCH(DMI_PRODUCT_VERSION, model) \ } \ } -#define HDAPS_DMI_MATCH_NORMAL(vendor, model) \ - HDAPS_DMI_MATCH_INVERT(vendor, model, 0) - -/* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match - "ThinkPad T42p", so the order of the entries matters. - If your ThinkPad is not recognized, please update to latest - BIOS. This is especially the case for some R52 ThinkPads. */ -static struct dmi_system_id __initdata hdaps_whitelist[] = { - HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R50p", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R50"), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R51"), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R52"), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61i", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T41p", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T41"), - HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T42p", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T42"), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T43"), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T60", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61p", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad X40"), - HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X41", HDAPS_Y_AXIS), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61s", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad Z60m"), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61m", HDAPS_BOTH_AXES), - HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61p", HDAPS_BOTH_AXES), +/* List of models with abnormal axis configuration. + Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match + "ThinkPad T42p", and enumeration stops after first match, + so the order of the entries matters. */ +struct dmi_system_id __initdata hdaps_whitelist[] = { + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R50p", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R60", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T41p", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T42p", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X40", HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X41", HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R60", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R400", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R500", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T60", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60 Tablet", HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60s", HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_X), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_X), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400s", HDAPS_ORIENT_INVERT_X), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T410s", HDAPS_ORIENT_SWAP), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T410", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T500", HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T510", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_X | HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad W510", HDAPS_ORIENT_MAX), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad W520", HDAPS_ORIENT_MAX), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X200s", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X200", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_X | HDAPS_ORIENT_INVERT_Y), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X201 Tablet", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X201s", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_XY), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X201", HDAPS_ORIENT_SWAP | HDAPS_ORIENT_INVERT_X), + HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X220", HDAPS_ORIENT_SWAP), { .ident = NULL } }; static int __init hdaps_init(void) { - struct input_dev *idev; int ret; - if (!dmi_check_system(hdaps_whitelist)) { - pr_warn("supported laptop not found!\n"); - ret = -ENODEV; - goto out; - } - - if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) { - ret = -ENXIO; - goto out; - } + /* Determine axis orientation orientation */ + if (hdaps_invert == HDAPS_ORIENT_UNDEFINED) /* set by module param? */ + if (dmi_check_system(hdaps_whitelist) < 1) /* in whitelist? */ + hdaps_invert = 0; /* default */ + /* Init timer before platform_driver_register, in case of suspend */ + init_timer(&hdaps_timer); + hdaps_timer.function = hdaps_mousedev_poll; ret = platform_driver_register(&hdaps_driver); if (ret) - goto out_region; + goto out; pdev = platform_device_register_simple("hdaps", -1, NULL, 0); if (IS_ERR(pdev)) { @@ -571,47 +793,79 @@ static int __init hdaps_init(void) if (ret) goto out_device; - hdaps_idev = input_allocate_polled_device(); + hdaps_idev = input_allocate_device(); if (!hdaps_idev) { ret = -ENOMEM; goto out_group; } - hdaps_idev->poll = hdaps_mousedev_poll; - hdaps_idev->poll_interval = HDAPS_POLL_INTERVAL; - - /* initial calibrate for the input device */ - hdaps_calibrate(); + hdaps_idev_raw = input_allocate_device(); + if (!hdaps_idev_raw) { + ret = -ENOMEM; + goto out_idev_first; + } - /* initialize the input class */ - idev = hdaps_idev->input; - idev->name = "hdaps"; - idev->phys = "isa1600/input0"; - idev->id.bustype = BUS_ISA; - idev->dev.parent = &pdev->dev; - idev->evbit[0] = BIT_MASK(EV_ABS); - input_set_abs_params(idev, ABS_X, + /* calibration for the input device (deferred to avoid delay) */ + needs_calibration = 1; + + /* initialize the joystick-like fuzzed input device */ + hdaps_idev->name = "ThinkPad HDAPS joystick emulation"; + hdaps_idev->phys = "hdaps/input0"; + hdaps_idev->id.bustype = BUS_HOST; + hdaps_idev->id.vendor = HDAPS_INPUT_VENDOR; + hdaps_idev->id.product = HDAPS_INPUT_PRODUCT; + hdaps_idev->id.version = HDAPS_INPUT_JS_VERSION; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + hdaps_idev->cdev.dev = &pdev->dev; +#endif + hdaps_idev->evbit[0] = BIT(EV_ABS); + hdaps_idev->open = hdaps_mousedev_open; + hdaps_idev->close = hdaps_mousedev_close; + input_set_abs_params(hdaps_idev, ABS_X, -256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT); - input_set_abs_params(idev, ABS_Y, + input_set_abs_params(hdaps_idev, ABS_Y, -256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT); - ret = input_register_polled_device(hdaps_idev); + ret = input_register_device(hdaps_idev); if (ret) goto out_idev; - pr_info("driver successfully loaded\n"); + /* initialize the raw data input device */ + hdaps_idev_raw->name = "ThinkPad HDAPS accelerometer data"; + hdaps_idev_raw->phys = "hdaps/input1"; + hdaps_idev_raw->id.bustype = BUS_HOST; + hdaps_idev_raw->id.vendor = HDAPS_INPUT_VENDOR; + hdaps_idev_raw->id.product = HDAPS_INPUT_PRODUCT; + hdaps_idev_raw->id.version = HDAPS_INPUT_RAW_VERSION; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + hdaps_idev_raw->cdev.dev = &pdev->dev; +#endif + hdaps_idev_raw->evbit[0] = BIT(EV_ABS); + hdaps_idev_raw->open = hdaps_mousedev_open; + hdaps_idev_raw->close = hdaps_mousedev_close; + input_set_abs_params(hdaps_idev_raw, ABS_X, -32768, 32767, 0, 0); + input_set_abs_params(hdaps_idev_raw, ABS_Y, -32768, 32767, 0, 0); + + ret = input_register_device(hdaps_idev_raw); + if (ret) + goto out_idev_reg_first; + + pr_info("driver successfully loaded.\n"); return 0; +out_idev_reg_first: + input_unregister_device(hdaps_idev); out_idev: - input_free_polled_device(hdaps_idev); + input_free_device(hdaps_idev_raw); +out_idev_first: + input_free_device(hdaps_idev); out_group: sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group); out_device: platform_device_unregister(pdev); out_driver: platform_driver_unregister(&hdaps_driver); -out_region: - release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS); + hdaps_device_shutdown(); out: pr_warn("driver init failed (ret=%d)!\n", ret); return ret; @@ -619,12 +873,12 @@ out: static void __exit hdaps_exit(void) { - input_unregister_polled_device(hdaps_idev); - input_free_polled_device(hdaps_idev); + input_unregister_device(hdaps_idev_raw); + input_unregister_device(hdaps_idev); + hdaps_device_shutdown(); /* ignore errors, effect is negligible */ sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group); platform_device_unregister(pdev); platform_driver_unregister(&hdaps_driver); - release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS); pr_info("driver unloaded\n"); } @@ -632,9 +886,8 @@ static void __exit hdaps_exit(void) module_init(hdaps_init); module_exit(hdaps_exit); -module_param_named(invert, hdaps_invert, int, 0); -MODULE_PARM_DESC(invert, "invert data along each axis. 1 invert x-axis, " - "2 invert y-axis, 3 invert both axes."); +module_param_named(invert, hdaps_invert, uint, 0); +MODULE_PARM_DESC(invert, "axis orientation code"); MODULE_AUTHOR("Robert Love"); MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver"); diff --git b/drivers/platform/x86/thinkpad_ec.c b/drivers/platform/x86/thinkpad_ec.c new file mode 100644 index 0000000..597614b --- /dev/null +++ b/drivers/platform/x86/thinkpad_ec.c @@ -0,0 +1,513 @@ +/* + * thinkpad_ec.c - ThinkPad embedded controller LPC3 functions + * + * The embedded controller on ThinkPad laptops has a non-standard interface, + * where LPC channel 3 of the H8S EC chip is hooked up to IO ports + * 0x1600-0x161F and implements (a special case of) the H8S LPC protocol. + * The EC LPC interface provides various system management services (currently + * known: battery information and accelerometer readouts). This driver + * provides access and mutual exclusion for the EC interface. +* + * The LPC protocol and terminology are documented here: + * "H8S/2104B Group Hardware Manual", + * http://documentation.renesas.com/eng/products/mpumcu/rej09b0300_2140bhm.pdf + * + * Copyright (C) 2006-2007 Shem Multinymous + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26) + #include +#else + #include +#endif + +#define TP_VERSION "0.42" + +MODULE_AUTHOR("Shem Multinymous"); +MODULE_DESCRIPTION("ThinkPad embedded controller hardware access"); +MODULE_VERSION(TP_VERSION); +MODULE_LICENSE("GPL"); + +/* IO ports used by embedded controller LPC channel 3: */ +#define TPC_BASE_PORT 0x1600 +#define TPC_NUM_PORTS 0x20 +#define TPC_STR3_PORT 0x1604 /* Reads H8S EC register STR3 */ +#define TPC_TWR0_PORT 0x1610 /* Mapped to H8S EC register TWR0MW/SW */ +#define TPC_TWR15_PORT 0x161F /* Mapped to H8S EC register TWR15. */ + /* (and port TPC_TWR0_PORT+i is mapped to H8S reg TWRi for 00x%02x", \ + msg, args->val[0x0], args->val[0xF], code) + +/* State of request prefetching: */ +static u8 prefetch_arg0, prefetch_argF; /* Args of last prefetch */ +static u64 prefetch_jiffies; /* time of prefetch, or: */ +#define TPC_PREFETCH_NONE INITIAL_JIFFIES /* No prefetch */ +#define TPC_PREFETCH_JUNK (INITIAL_JIFFIES+1) /* Ignore prefetch */ + +/* Locking: */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37) +static DECLARE_MUTEX(thinkpad_ec_mutex); +#else +static DEFINE_SEMAPHORE(thinkpad_ec_mutex); +#endif + +/* Kludge in case the ACPI DSDT reserves the ports we need. */ +static bool force_io; /* Willing to do IO to ports we couldn't reserve? */ +static int reserved_io; /* Successfully reserved the ports? */ +module_param_named(force_io, force_io, bool, 0600); +MODULE_PARM_DESC(force_io, "Force IO even if region already reserved (0=off, 1=on)"); + +/** + * thinkpad_ec_lock - get lock on the ThinkPad EC + * + * Get exclusive lock for accesing the ThinkPad embedded controller LPC3 + * interface. Returns 0 iff lock acquired. + */ +int thinkpad_ec_lock(void) +{ + int ret; + ret = down_interruptible(&thinkpad_ec_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_lock); + +/** + * thinkpad_ec_try_lock - try getting lock on the ThinkPad EC + * + * Try getting an exclusive lock for accesing the ThinkPad embedded + * controller LPC3. Returns immediately if lock is not available; neither + * blocks nor sleeps. Returns 0 iff lock acquired . + */ +int thinkpad_ec_try_lock(void) +{ + return down_trylock(&thinkpad_ec_mutex); +} +EXPORT_SYMBOL_GPL(thinkpad_ec_try_lock); + +/** + * thinkpad_ec_unlock - release lock on ThinkPad EC + * + * Release a previously acquired exclusive lock on the ThinkPad ebmedded + * controller LPC3 interface. + */ +void thinkpad_ec_unlock(void) +{ + up(&thinkpad_ec_mutex); +} +EXPORT_SYMBOL_GPL(thinkpad_ec_unlock); + +/** + * thinkpad_ec_request_row - tell embedded controller to prepare a row + * @args Input register arguments + * + * Requests a data row by writing to H8S LPC registers TRW0 through TWR15 (or + * a subset thereof) following the protocol prescribed by the "H8S/2104B Group + * Hardware Manual". Does sanity checks via status register STR3. + */ +static int thinkpad_ec_request_row(const struct thinkpad_ec_row *args) +{ + u8 str3; + int i; + + /* EC protocol requires write to TWR0 (function code): */ + if (!(args->mask & 0x0001)) { + printk(KERN_ERR MSG_FMT("bad args->mask=0x%02x", args->mask)); + return -EINVAL; + } + + /* Check initial STR3 status: */ + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_OBF3B) { /* data already pending */ + inb(TPC_TWR15_PORT); /* marks end of previous transaction */ + if (prefetch_jiffies == TPC_PREFETCH_NONE) + printk(KERN_WARNING REQ_FMT( + "EC has result from unrequested transaction", + str3)); + return -EBUSY; /* EC will be ready in a few usecs */ + } else if (str3 == H8S_STR3_SWMF) { /* busy with previous request */ + if (prefetch_jiffies == TPC_PREFETCH_NONE) + printk(KERN_WARNING REQ_FMT( + "EC is busy with unrequested transaction", + str3)); + return -EBUSY; /* data will be pending in a few usecs */ + } else if (str3 != 0x00) { /* unexpected status? */ + printk(KERN_WARNING REQ_FMT("unexpected initial STR3", str3)); + return -EIO; + } + + /* Send TWR0MW: */ + outb(args->val[0], TPC_TWR0_PORT); + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 != H8S_STR3_MWMF) { /* not accepted? */ + printk(KERN_WARNING REQ_FMT("arg0 rejected", str3)); + return -EIO; + } + + /* Send TWR1 through TWR14: */ + for (i = 1; i < TP_CONTROLLER_ROW_LEN-1; i++) + if ((args->mask>>i)&1) + outb(args->val[i], TPC_TWR0_PORT+i); + + /* Send TWR15 (default to 0x01). This marks end of command. */ + outb((args->mask & 0x8000) ? args->val[0xF] : 0x01, TPC_TWR15_PORT); + + /* Wait until EC starts writing its reply (~60ns on average). + * Releasing locks before this happens may cause an EC hang + * due to firmware bug! + */ + for (i = 0; i < TPC_REQUEST_RETRIES; i++) { + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_SWMF) /* EC started replying */ + return 0; + else if (!(str3 & ~(H8S_STR3_IBF3B|H8S_STR3_MWMF))) + /* Normal progress (the EC hasn't seen the request + * yet, or is processing it). Wait it out. */ + ndelay(TPC_REQUEST_NDELAY); + else { /* weird EC status */ + printk(KERN_WARNING + REQ_FMT("bad end STR3", str3)); + return -EIO; + } + } + printk(KERN_WARNING REQ_FMT("EC is mysteriously silent", str3)); + return -EIO; +} + +/** + * thinkpad_ec_read_data - read pre-requested row-data from EC + * @args Input register arguments of pre-requested rows + * @data Output register values + * + * Reads current row data from the controller, assuming it's already + * requested. Follows the H8S spec for register access and status checks. + */ +static int thinkpad_ec_read_data(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int i; + u8 str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + /* Once we make a request, STR3 assumes the sequence of values listed + * in the following 'if' as it reads the request and writes its data. + * It takes about a few dozen nanosecs total, with very high variance. + */ + if (str3 == (H8S_STR3_IBF3B|H8S_STR3_MWMF) || + str3 == 0x00 || /* the 0x00 is indistinguishable from idle EC! */ + str3 == H8S_STR3_SWMF) + return -EBUSY; /* not ready yet */ + /* Finally, the EC signals output buffer full: */ + if (str3 != (H8S_STR3_OBF3B|H8S_STR3_SWMF)) { + printk(KERN_WARNING + REQ_FMT("bad initial STR3", str3)); + return -EIO; + } + + /* Read first byte (signals start of read transactions): */ + data->val[0] = inb(TPC_TWR0_PORT); + /* Optionally read 14 more bytes: */ + for (i = 1; i < TP_CONTROLLER_ROW_LEN-1; i++) + if ((data->mask >> i)&1) + data->val[i] = inb(TPC_TWR0_PORT+i); + /* Read last byte from 0x161F (signals end of read transaction): */ + data->val[0xF] = inb(TPC_TWR15_PORT); + + /* Readout still pending? */ + str3 = inb(TPC_STR3_PORT) & H8S_STR3_MASK; + if (str3 & H8S_STR3_OBF3B) + printk(KERN_WARNING + REQ_FMT("OBF3B=1 after read", str3)); + /* If port 0x161F returns 0x80 too often, the EC may lock up. Warn: */ + if (data->val[0xF] == 0x80) + printk(KERN_WARNING + REQ_FMT("0x161F reports error", data->val[0xF])); + return 0; +} + +/** + * thinkpad_ec_is_row_fetched - is the given row currently prefetched? + * + * To keep things simple we compare only the first and last args; + * this suffices for all known cases. + */ +static int thinkpad_ec_is_row_fetched(const struct thinkpad_ec_row *args) +{ + return (prefetch_jiffies != TPC_PREFETCH_NONE) && + (prefetch_jiffies != TPC_PREFETCH_JUNK) && + (prefetch_arg0 == args->val[0]) && + (prefetch_argF == args->val[0xF]) && + (get_jiffies_64() < prefetch_jiffies + TPC_PREFETCH_TIMEOUT); +} + +/** + * thinkpad_ec_read_row - request and read data from ThinkPad EC + * @args Input register arguments + * @data Output register values + * + * Read a data row from the ThinkPad embedded controller LPC3 interface. + * Does fetching and retrying if needed. The row is specified by an + * array of 16 bytes, some of which may be undefined (but the first is + * mandatory). These bytes are given in @args->val[], where @args->val[i] is + * used iff (@args->mask>>i)&1). The resulting row data is stored in + * @data->val[], but is only guaranteed to be valid for indices corresponding + * to set bit in @data->mask. That is, if @data->mask&(1<val[i] is undefined. + * + * Returns -EBUSY on transient error and -EIO on abnormal condition. + * Caller must hold controller lock. + */ +int thinkpad_ec_read_row(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int retries, ret; + + if (thinkpad_ec_is_row_fetched(args)) + goto read_row; /* already requested */ + + /* Request the row */ + for (retries = 0; retries < TPC_READ_RETRIES; ++retries) { + ret = thinkpad_ec_request_row(args); + if (!ret) + goto read_row; + if (ret != -EBUSY) + break; + ndelay(TPC_READ_NDELAY); + } + printk(KERN_ERR REQ_FMT("failed requesting row", ret)); + goto out; + +read_row: + /* Read the row's data */ + for (retries = 0; retries < TPC_READ_RETRIES; ++retries) { + ret = thinkpad_ec_read_data(args, data); + if (!ret) + goto out; + if (ret != -EBUSY) + break; + ndelay(TPC_READ_NDELAY); + } + + printk(KERN_ERR REQ_FMT("failed waiting for data", ret)); + +out: + prefetch_jiffies = TPC_PREFETCH_JUNK; + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_read_row); + +/** + * thinkpad_ec_try_read_row - try reading prefetched data from ThinkPad EC + * @args Input register arguments + * @data Output register values + * + * Try reading a data row from the ThinkPad embedded controller LPC3 + * interface, if this raw was recently prefetched using + * thinkpad_ec_prefetch_row(). Does not fetch, retry or block. + * The parameters have the same meaning as in thinkpad_ec_read_row(). + * + * Returns -EBUSY is data not ready and -ENODATA if row not prefetched. + * Caller must hold controller lock. + */ +int thinkpad_ec_try_read_row(const struct thinkpad_ec_row *args, + struct thinkpad_ec_row *data) +{ + int ret; + if (!thinkpad_ec_is_row_fetched(args)) { + ret = -ENODATA; + } else { + ret = thinkpad_ec_read_data(args, data); + if (!ret) + prefetch_jiffies = TPC_PREFETCH_NONE; /* eaten up */ + } + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_try_read_row); + +/** + * thinkpad_ec_prefetch_row - prefetch data from ThinkPad EC + * @args Input register arguments + * + * Prefetch a data row from the ThinkPad embedded controller LCP3 + * interface. A subsequent call to thinkpad_ec_read_row() with the + * same arguments will be faster, and a subsequent call to + * thinkpad_ec_try_read_row() stands a good chance of succeeding if + * done neither too soon nor too late. See + * thinkpad_ec_read_row() for the meaning of @args. + * + * Returns -EBUSY on transient error and -EIO on abnormal condition. + * Caller must hold controller lock. + */ +int thinkpad_ec_prefetch_row(const struct thinkpad_ec_row *args) +{ + int ret; + ret = thinkpad_ec_request_row(args); + if (ret) { + prefetch_jiffies = TPC_PREFETCH_JUNK; + } else { + prefetch_jiffies = get_jiffies_64(); + prefetch_arg0 = args->val[0x0]; + prefetch_argF = args->val[0xF]; + } + return ret; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_prefetch_row); + +/** + * thinkpad_ec_invalidate - invalidate prefetched ThinkPad EC data + * + * Invalidate the data prefetched via thinkpad_ec_prefetch_row() from the + * ThinkPad embedded controller LPC3 interface. + * Must be called before unlocking by any code that accesses the controller + * ports directly. + */ +void thinkpad_ec_invalidate(void) +{ + prefetch_jiffies = TPC_PREFETCH_JUNK; +} +EXPORT_SYMBOL_GPL(thinkpad_ec_invalidate); + + +/*** Checking for EC hardware ***/ + +/** + * thinkpad_ec_test - verify the EC is present and follows protocol + * + * Ensure the EC LPC3 channel really works on this machine by making + * an EC request and seeing if the EC follows the documented H8S protocol. + * The requested row just reads battery status, so it should be harmless to + * access it (on a correct EC). + * This test writes to IO ports, so execute only after checking DMI. + */ +static int __init thinkpad_ec_test(void) +{ + int ret; + const struct thinkpad_ec_row args = /* battery 0 basic status */ + { .mask = 0x8001, .val = {0x01,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0x00} }; + struct thinkpad_ec_row data = { .mask = 0x0000 }; + ret = thinkpad_ec_lock(); + if (ret) + return ret; + ret = thinkpad_ec_read_row(&args, &data); + thinkpad_ec_unlock(); + return ret; +} + +/* Search all DMI device names of a given type for a substring */ +static int __init dmi_find_substring(int type, const char *substr) +{ + const struct dmi_device *dev = NULL; + while ((dev = dmi_find_device(type, NULL, dev))) { + if (strstr(dev->name, substr)) + return 1; + } + return 0; +} + +#define TP_DMI_MATCH(vendor,model) { \ + .ident = vendor " " model, \ + .matches = { \ + DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ + DMI_MATCH(DMI_PRODUCT_VERSION, model) \ + } \ +} + +/* Check DMI for existence of ThinkPad embedded controller */ +static int __init check_dmi_for_ec(void) +{ + /* A few old models that have a good EC but don't report it in DMI */ + struct dmi_system_id tp_whitelist[] = { + TP_DMI_MATCH("IBM", "ThinkPad A30"), + TP_DMI_MATCH("IBM", "ThinkPad T23"), + TP_DMI_MATCH("IBM", "ThinkPad X24"), + TP_DMI_MATCH("LENOVO", "ThinkPad"), + { .ident = NULL } + }; + return dmi_find_substring(DMI_DEV_TYPE_OEM_STRING, + "IBM ThinkPad Embedded Controller") || + dmi_check_system(tp_whitelist); +} + +/*** Init and cleanup ***/ + +static int __init thinkpad_ec_init(void) +{ + if (!check_dmi_for_ec()) { + printk(KERN_WARNING + "thinkpad_ec: no ThinkPad embedded controller!\n"); + return -ENODEV; + } + + if (request_region(TPC_BASE_PORT, TPC_NUM_PORTS, "thinkpad_ec")) { + reserved_io = 1; + } else { + printk(KERN_ERR "thinkpad_ec: cannot claim IO ports %#x-%#x... ", + TPC_BASE_PORT, + TPC_BASE_PORT + TPC_NUM_PORTS - 1); + if (force_io) { + printk("forcing use of unreserved IO ports.\n"); + } else { + printk("consider using force_io=1.\n"); + return -ENXIO; + } + } + prefetch_jiffies = TPC_PREFETCH_JUNK; + if (thinkpad_ec_test()) { + printk(KERN_ERR "thinkpad_ec: initial ec test failed\n"); + if (reserved_io) + release_region(TPC_BASE_PORT, TPC_NUM_PORTS); + return -ENXIO; + } + printk(KERN_INFO "thinkpad_ec: thinkpad_ec " TP_VERSION " loaded.\n"); + return 0; +} + +static void __exit thinkpad_ec_exit(void) +{ + if (reserved_io) + release_region(TPC_BASE_PORT, TPC_NUM_PORTS); + printk(KERN_INFO "thinkpad_ec: unloaded.\n"); +} + +module_init(thinkpad_ec_init); +module_exit(thinkpad_ec_exit); diff --git b/drivers/platform/x86/tp_smapi.c b/drivers/platform/x86/tp_smapi.c new file mode 100644 index 0000000..209cb64 --- /dev/null +++ b/drivers/platform/x86/tp_smapi.c @@ -0,0 +1,1493 @@ +/* + * tp_smapi.c - ThinkPad SMAPI support + * + * This driver exposes some features of the System Management Application + * Program Interface (SMAPI) BIOS found on ThinkPad laptops. It works on + * models in which the SMAPI BIOS runs in SMM and is invoked by writing + * to the APM control port 0xB2. + * It also exposes battery status information, obtained from the ThinkPad + * embedded controller (via the thinkpad_ec module). + * Ancient ThinkPad models use a different interface, supported by the + * "thinkpad" module from "tpctl". + * + * Many of the battery status values obtained from the EC simply mirror + * values provided by the battery's Smart Battery System (SBS) interface, so + * their meaning is defined by the Smart Battery Data Specification (see + * http://sbs-forum.org/specs/sbdat110.pdf). References to this SBS spec + * are given in the code where relevant. + * + * Copyright (C) 2006 Shem Multinymous . + * SMAPI access code based on the mwave driver by Mike Sullivan. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include /* CMOS defines */ +#include +#include +#include +#include +#include +#include + +#define TP_VERSION "0.42" +#define TP_DESC "ThinkPad SMAPI Support" +#define TP_DIR "smapi" + +MODULE_AUTHOR("Shem Multinymous"); +MODULE_DESCRIPTION(TP_DESC); +MODULE_VERSION(TP_VERSION); +MODULE_LICENSE("GPL"); + +static struct platform_device *pdev; + +static int tp_debug; +module_param_named(debug, tp_debug, int, 0600); +MODULE_PARM_DESC(debug, "Debug level (0=off, 1=on)"); + +/* A few macros for printk()ing: */ +#define TPRINTK(level, fmt, args...) \ + dev_printk(level, &(pdev->dev), "%s: " fmt "\n", __func__, ## args) +#define DPRINTK(fmt, args...) \ + do { if (tp_debug) TPRINTK(KERN_DEBUG, fmt, ## args); } while (0) + +/********************************************************************* + * SMAPI interface + */ + +/* SMAPI functions (register BX when making the SMM call). */ +#define SMAPI_GET_INHIBIT_CHARGE 0x2114 +#define SMAPI_SET_INHIBIT_CHARGE 0x2115 +#define SMAPI_GET_THRESH_START 0x2116 +#define SMAPI_SET_THRESH_START 0x2117 +#define SMAPI_GET_FORCE_DISCHARGE 0x2118 +#define SMAPI_SET_FORCE_DISCHARGE 0x2119 +#define SMAPI_GET_THRESH_STOP 0x211a +#define SMAPI_SET_THRESH_STOP 0x211b + +/* SMAPI error codes (see ThinkPad 770 Technical Reference Manual p.83 at + http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=PFAN-3TUQQD */ +#define SMAPI_RETCODE_EOF 0xff +static struct { u8 rc; char *msg; int ret; } smapi_retcode[] = +{ + {0x00, "OK", 0}, + {0x53, "SMAPI function is not available", -ENXIO}, + {0x81, "Invalid parameter", -EINVAL}, + {0x86, "Function is not supported by SMAPI BIOS", -EOPNOTSUPP}, + {0x90, "System error", -EIO}, + {0x91, "System is invalid", -EIO}, + {0x92, "System is busy, -EBUSY"}, + {0xa0, "Device error (disk read error)", -EIO}, + {0xa1, "Device is busy", -EBUSY}, + {0xa2, "Device is not attached", -ENXIO}, + {0xa3, "Device is disbled", -EIO}, + {0xa4, "Request parameter is out of range", -EINVAL}, + {0xa5, "Request parameter is not accepted", -EINVAL}, + {0xa6, "Transient error", -EBUSY}, /* ? */ + {SMAPI_RETCODE_EOF, "Unknown error code", -EIO} +}; + + +#define SMAPI_MAX_RETRIES 10 +#define SMAPI_PORT2 0x4F /* fixed port, meaning unclear */ +static unsigned short smapi_port; /* APM control port, normally 0xB2 */ + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37) +static DECLARE_MUTEX(smapi_mutex); +#else +static DEFINE_SEMAPHORE(smapi_mutex); +#endif + +/** + * find_smapi_port - read SMAPI port from NVRAM + */ +static int __init find_smapi_port(void) +{ + u16 smapi_id = 0; + unsigned short port = 0; + unsigned long flags; + + spin_lock_irqsave(&rtc_lock, flags); + smapi_id = CMOS_READ(0x7C); + smapi_id |= (CMOS_READ(0x7D) << 8); + spin_unlock_irqrestore(&rtc_lock, flags); + + if (smapi_id != 0x5349) { + printk(KERN_ERR "SMAPI not supported (ID=0x%x)\n", smapi_id); + return -ENXIO; + } + spin_lock_irqsave(&rtc_lock, flags); + port = CMOS_READ(0x7E); + port |= (CMOS_READ(0x7F) << 8); + spin_unlock_irqrestore(&rtc_lock, flags); + if (port == 0) { + printk(KERN_ERR "unable to read SMAPI port number\n"); + return -ENXIO; + } + return port; +} + +/** + * smapi_request - make a SMAPI call + * @inEBX, @inECX, @inEDI, @inESI: input registers + * @outEBX, @outECX, @outEDX, @outEDI, @outESI: outputs registers + * @msg: textual error message + * Invokes the SMAPI SMBIOS with the given input and outpu args. + * All outputs are optional (can be %NULL). + * Returns 0 when successful, and a negative errno constant + * (see smapi_retcode above) upon failure. + */ +static int smapi_request(u32 inEBX, u32 inECX, + u32 inEDI, u32 inESI, + u32 *outEBX, u32 *outECX, u32 *outEDX, + u32 *outEDI, u32 *outESI, const char **msg) +{ + int ret = 0; + int i; + int retries; + u8 rc; + /* Must use local vars for output regs, due to reg pressure. */ + u32 tmpEAX, tmpEBX, tmpECX, tmpEDX, tmpEDI, tmpESI; + + for (retries = 0; retries < SMAPI_MAX_RETRIES; ++retries) { + DPRINTK("req_in: BX=%x CX=%x DI=%x SI=%x", + inEBX, inECX, inEDI, inESI); + + /* SMAPI's SMBIOS call and thinkpad_ec end up using use + * different interfaces to the same chip, so play it safe. */ + ret = thinkpad_ec_lock(); + if (ret) + return ret; + + __asm__ __volatile__( + "movl $0x00005380,%%eax\n\t" + "movl %6,%%ebx\n\t" + "movl %7,%%ecx\n\t" + "movl %8,%%edi\n\t" + "movl %9,%%esi\n\t" + "xorl %%edx,%%edx\n\t" + "movw %10,%%dx\n\t" + "out %%al,%%dx\n\t" /* trigger SMI to SMBIOS */ + "out %%al,$0x4F\n\t" + "movl %%eax,%0\n\t" + "movl %%ebx,%1\n\t" + "movl %%ecx,%2\n\t" + "movl %%edx,%3\n\t" + "movl %%edi,%4\n\t" + "movl %%esi,%5\n\t" + :"=m"(tmpEAX), + "=m"(tmpEBX), + "=m"(tmpECX), + "=m"(tmpEDX), + "=m"(tmpEDI), + "=m"(tmpESI) + :"m"(inEBX), "m"(inECX), "m"(inEDI), "m"(inESI), + "m"((u16)smapi_port) + :"%eax", "%ebx", "%ecx", "%edx", "%edi", + "%esi"); + + thinkpad_ec_invalidate(); + thinkpad_ec_unlock(); + + /* Don't let the next SMAPI access happen too quickly, + * may case problems. (We're hold smapi_mutex). */ + msleep(50); + + if (outEBX) *outEBX = tmpEBX; + if (outECX) *outECX = tmpECX; + if (outEDX) *outEDX = tmpEDX; + if (outESI) *outESI = tmpESI; + if (outEDI) *outEDI = tmpEDI; + + /* Look up error code */ + rc = (tmpEAX>>8)&0xFF; + for (i = 0; smapi_retcode[i].rc != SMAPI_RETCODE_EOF && + smapi_retcode[i].rc != rc; ++i) {} + ret = smapi_retcode[i].ret; + if (msg) + *msg = smapi_retcode[i].msg; + + DPRINTK("req_out: AX=%x BX=%x CX=%x DX=%x DI=%x SI=%x r=%d", + tmpEAX, tmpEBX, tmpECX, tmpEDX, tmpEDI, tmpESI, ret); + if (ret) + TPRINTK(KERN_NOTICE, "SMAPI error: %s (func=%x)", + smapi_retcode[i].msg, inEBX); + + if (ret != -EBUSY) + return ret; + } + return ret; +} + +/* Convenience wrapper: discard output arguments */ +static int smapi_write(u32 inEBX, u32 inECX, + u32 inEDI, u32 inESI, const char **msg) +{ + return smapi_request(inEBX, inECX, inEDI, inESI, + NULL, NULL, NULL, NULL, NULL, msg); +} + + +/********************************************************************* + * Specific SMAPI services + * All of these functions return 0 upon success, and a negative errno + * constant (see smapi_retcode) on failure. + */ + +enum thresh_type { + THRESH_STOP = 0, /* the code assumes this is 0 for brevity */ + THRESH_START +}; +#define THRESH_NAME(which) ((which == THRESH_START) ? "start" : "stop") + +/** + * __get_real_thresh - read battery charge start/stop threshold from SMAPI + * @bat: battery number (0 or 1) + * @which: THRESH_START or THRESH_STOP + * @thresh: 1..99, 0=default 1..99, 0=default (pass this as-is to SMAPI) + * @outEDI: some additional state that needs to be preserved, meaning unknown + * @outESI: some additional state that needs to be preserved, meaning unknown + */ +static int __get_real_thresh(int bat, enum thresh_type which, int *thresh, + u32 *outEDI, u32 *outESI) +{ + u32 ebx = (which == THRESH_START) ? SMAPI_GET_THRESH_START + : SMAPI_GET_THRESH_STOP; + u32 ecx = (bat+1)<<8; + const char *msg; + int ret = smapi_request(ebx, ecx, 0, 0, NULL, + &ecx, NULL, outEDI, outESI, &msg); + if (ret) { + TPRINTK(KERN_NOTICE, "cannot get %s_thresh of bat=%d: %s", + THRESH_NAME(which), bat, msg); + return ret; + } + if (!(ecx&0x00000100)) { + TPRINTK(KERN_NOTICE, "cannot get %s_thresh of bat=%d: ecx=0%x", + THRESH_NAME(which), bat, ecx); + return -EIO; + } + if (thresh) + *thresh = ecx&0xFF; + return 0; +} + +/** + * get_real_thresh - read battery charge start/stop threshold from SMAPI + * @bat: battery number (0 or 1) + * @which: THRESH_START or THRESH_STOP + * @thresh: 1..99, 0=default (passes as-is to SMAPI) + */ +static int get_real_thresh(int bat, enum thresh_type which, int *thresh) +{ + return __get_real_thresh(bat, which, thresh, NULL, NULL); +} + +/** + * set_real_thresh - write battery start/top charge threshold to SMAPI + * @bat: battery number (0 or 1) + * @which: THRESH_START or THRESH_STOP + * @thresh: 1..99, 0=default (passes as-is to SMAPI) + */ +static int set_real_thresh(int bat, enum thresh_type which, int thresh) +{ + u32 ebx = (which == THRESH_START) ? SMAPI_SET_THRESH_START + : SMAPI_SET_THRESH_STOP; + u32 ecx = ((bat+1)<<8) + thresh; + u32 getDI, getSI; + const char *msg; + int ret; + + /* verify read before writing */ + ret = __get_real_thresh(bat, which, NULL, &getDI, &getSI); + if (ret) + return ret; + + ret = smapi_write(ebx, ecx, getDI, getSI, &msg); + if (ret) + TPRINTK(KERN_NOTICE, "set %s to %d for bat=%d failed: %s", + THRESH_NAME(which), thresh, bat, msg); + else + TPRINTK(KERN_INFO, "set %s to %d for bat=%d", + THRESH_NAME(which), thresh, bat); + return ret; +} + +/** + * __get_inhibit_charge_minutes - get inhibit charge period from SMAPI + * @bat: battery number (0 or 1) + * @minutes: period in minutes (1..65535 minutes, 0=disabled) + * @outECX: some additional state that needs to be preserved, meaning unknown + * Note that @minutes is the originally set value, it does not count down. + */ +static int __get_inhibit_charge_minutes(int bat, int *minutes, u32 *outECX) +{ + u32 ecx = (bat+1)<<8; + u32 esi; + const char *msg; + int ret = smapi_request(SMAPI_GET_INHIBIT_CHARGE, ecx, 0, 0, + NULL, &ecx, NULL, NULL, &esi, &msg); + if (ret) { + TPRINTK(KERN_NOTICE, "failed for bat=%d: %s", bat, msg); + return ret; + } + if (!(ecx&0x0100)) { + TPRINTK(KERN_NOTICE, "bad ecx=0x%x for bat=%d", ecx, bat); + return -EIO; + } + if (minutes) + *minutes = (ecx&0x0001)?esi:0; + if (outECX) + *outECX = ecx; + return 0; +} + +/** + * get_inhibit_charge_minutes - get inhibit charge period from SMAPI + * @bat: battery number (0 or 1) + * @minutes: period in minutes (1..65535 minutes, 0=disabled) + * Note that @minutes is the originally set value, it does not count down. + */ +static int get_inhibit_charge_minutes(int bat, int *minutes) +{ + return __get_inhibit_charge_minutes(bat, minutes, NULL); +} + +/** + * set_inhibit_charge_minutes - write inhibit charge period to SMAPI + * @bat: battery number (0 or 1) + * @minutes: period in minutes (1..65535 minutes, 0=disabled) + */ +static int set_inhibit_charge_minutes(int bat, int minutes) +{ + u32 ecx; + const char *msg; + int ret; + + /* verify read before writing */ + ret = __get_inhibit_charge_minutes(bat, NULL, &ecx); + if (ret) + return ret; + + ecx = ((bat+1)<<8) | (ecx&0x00FE) | (minutes > 0 ? 0x0001 : 0x0000); + if (minutes > 0xFFFF) + minutes = 0xFFFF; + ret = smapi_write(SMAPI_SET_INHIBIT_CHARGE, ecx, 0, minutes, &msg); + if (ret) + TPRINTK(KERN_NOTICE, + "set to %d failed for bat=%d: %s", minutes, bat, msg); + else + TPRINTK(KERN_INFO, "set to %d for bat=%d\n", minutes, bat); + return ret; +} + + +/** + * get_force_discharge - get status of forced discharging from SMAPI + * @bat: battery number (0 or 1) + * @enabled: 1 if forced discharged is enabled, 0 if not + */ +static int get_force_discharge(int bat, int *enabled) +{ + u32 ecx = (bat+1)<<8; + const char *msg; + int ret = smapi_request(SMAPI_GET_FORCE_DISCHARGE, ecx, 0, 0, + NULL, &ecx, NULL, NULL, NULL, &msg); + if (ret) { + TPRINTK(KERN_NOTICE, "failed for bat=%d: %s", bat, msg); + return ret; + } + *enabled = (!(ecx&0x00000100) && (ecx&0x00000001))?1:0; + return 0; +} + +/** + * set_force_discharge - write status of forced discharging to SMAPI + * @bat: battery number (0 or 1) + * @enabled: 1 if forced discharged is enabled, 0 if not + */ +static int set_force_discharge(int bat, int enabled) +{ + u32 ecx = (bat+1)<<8; + const char *msg; + int ret = smapi_request(SMAPI_GET_FORCE_DISCHARGE, ecx, 0, 0, + NULL, &ecx, NULL, NULL, NULL, &msg); + if (ret) { + TPRINTK(KERN_NOTICE, "get failed for bat=%d: %s", bat, msg); + return ret; + } + if (ecx&0x00000100) { + TPRINTK(KERN_NOTICE, "cannot force discharge bat=%d", bat); + return -EIO; + } + + ecx = ((bat+1)<<8) | (ecx&0x000000FA) | (enabled?0x00000001:0); + ret = smapi_write(SMAPI_SET_FORCE_DISCHARGE, ecx, 0, 0, &msg); + if (ret) + TPRINTK(KERN_NOTICE, "set to %d failed for bat=%d: %s", + enabled, bat, msg); + else + TPRINTK(KERN_INFO, "set to %d for bat=%d", enabled, bat); + return ret; +} + + +/********************************************************************* + * Wrappers to threshold-related SMAPI functions, which handle default + * thresholds and related quirks. + */ + +/* Minimum, default and minimum difference for battery charging thresholds: */ +#define MIN_THRESH_DELTA 4 /* Min delta between start and stop thresh */ +#define MIN_THRESH_START 2 +#define MAX_THRESH_START (100-MIN_THRESH_DELTA) +#define MIN_THRESH_STOP (MIN_THRESH_START + MIN_THRESH_DELTA) +#define MAX_THRESH_STOP 100 +#define DEFAULT_THRESH_START MAX_THRESH_START +#define DEFAULT_THRESH_STOP MAX_THRESH_STOP + +/* The GUI of IBM's Battery Maximizer seems to show a start threshold that + * is 1 more than the value we set/get via SMAPI. Since the threshold is + * maintained across reboot, this can be confusing. So we kludge our + * interface for interoperability: */ +#define BATMAX_FIX 1 + +/* Get charge start/stop threshold (1..100), + * substituting default values if needed and applying BATMAT_FIX. */ +static int get_thresh(int bat, enum thresh_type which, int *thresh) +{ + int ret = get_real_thresh(bat, which, thresh); + if (ret) + return ret; + if (*thresh == 0) + *thresh = (which == THRESH_START) ? DEFAULT_THRESH_START + : DEFAULT_THRESH_STOP; + else if (which == THRESH_START) + *thresh += BATMAX_FIX; + return 0; +} + + +/* Set charge start/stop threshold (1..100), + * substituting default values if needed and applying BATMAT_FIX. */ +static int set_thresh(int bat, enum thresh_type which, int thresh) +{ + if (which == THRESH_STOP && thresh == DEFAULT_THRESH_STOP) + thresh = 0; /* 100 is out of range, but default means 100 */ + if (which == THRESH_START) + thresh -= BATMAX_FIX; + return set_real_thresh(bat, which, thresh); +} + +/********************************************************************* + * ThinkPad embedded controller readout and basic functions + */ + +/** + * read_tp_ec_row - read data row from the ThinkPad embedded controller + * @arg0: EC command code + * @bat: battery number, 0 or 1 + * @j: the byte value to be used for "junk" (unused) input/outputs + * @dataval: result vector + */ +static int read_tp_ec_row(u8 arg0, int bat, u8 j, u8 *dataval) +{ + int ret; + const struct thinkpad_ec_row args = { .mask = 0xFFFF, + .val = {arg0, j,j,j,j,j,j,j,j,j,j,j,j,j,j, (u8)bat} }; + struct thinkpad_ec_row data = { .mask = 0xFFFF }; + + ret = thinkpad_ec_lock(); + if (ret) + return ret; + ret = thinkpad_ec_read_row(&args, &data); + thinkpad_ec_unlock(); + memcpy(dataval, &data.val, TP_CONTROLLER_ROW_LEN); + return ret; +} + +/** + * power_device_present - check for presence of battery or AC power + * @bat: 0 for battery 0, 1 for battery 1, otherwise AC power + * Returns 1 if present, 0 if not present, negative if error. + */ +static int power_device_present(int bat) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + u8 test; + int ret = read_tp_ec_row(1, bat, 0, row); + if (ret) + return ret; + switch (bat) { + case 0: test = 0x40; break; /* battery 0 */ + case 1: test = 0x20; break; /* battery 1 */ + default: test = 0x80; /* AC power */ + } + return (row[0] & test) ? 1 : 0; +} + +/** + * bat_has_status - check if battery can report detailed status + * @bat: 0 for battery 0, 1 for battery 1 + * Returns 1 if yes, 0 if no, negative if error. + */ +static int bat_has_status(int bat) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + int ret = read_tp_ec_row(1, bat, 0, row); + if (ret) + return ret; + if ((row[0] & (bat?0x20:0x40)) == 0) /* no battery */ + return 0; + if ((row[1] & (0x60)) == 0) /* no status */ + return 0; + return 1; +} + +/** + * get_tp_ec_bat_16 - read a 16-bit value from EC battery status data + * @arg0: first argument to EC + * @off: offset in row returned from EC + * @bat: battery (0 or 1) + * @val: the 16-bit value obtained + * Returns nonzero on error. + */ +static int get_tp_ec_bat_16(u8 arg0, int offset, int bat, u16 *val) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + int ret; + if (bat_has_status(bat) != 1) + return -ENXIO; + ret = read_tp_ec_row(arg0, bat, 0, row); + if (ret) + return ret; + *val = *(u16 *)(row+offset); + return 0; +} + +/********************************************************************* + * sysfs attributes for batteries - + * definitions and helper functions + */ + +/* A custom device attribute struct which holds a battery number */ +struct bat_device_attribute { + struct device_attribute dev_attr; + int bat; +}; + +/** + * attr_get_bat - get the battery to which the attribute belongs + */ +static int attr_get_bat(struct device_attribute *attr) +{ + return container_of(attr, struct bat_device_attribute, dev_attr)->bat; +} + +/** + * show_tp_ec_bat_u16 - show an unsigned 16-bit battery attribute + * @arg0: specified 1st argument of EC raw to read + * @offset: byte offset in EC raw data + * @mul: correction factor to multiply by + * @na_msg: string to output is value not available (0xFFFFFFFF) + * @attr: battery attribute + * @buf: output buffer + * The 16-bit value is read from the EC, treated as unsigned, + * transformed as x->mul*x, and printed to the buffer. + * If the value is 0xFFFFFFFF and na_msg!=%NULL, na_msg is printed instead. + */ +static ssize_t show_tp_ec_bat_u16(u8 arg0, int offset, int mul, + const char *na_msg, + struct device_attribute *attr, char *buf) +{ + u16 val; + int ret = get_tp_ec_bat_16(arg0, offset, attr_get_bat(attr), &val); + if (ret) + return ret; + if (na_msg && val == 0xFFFF) + return sprintf(buf, "%s\n", na_msg); + else + return sprintf(buf, "%u\n", mul*(unsigned int)val); +} + +/** + * show_tp_ec_bat_s16 - show an signed 16-bit battery attribute + * @arg0: specified 1st argument of EC raw to read + * @offset: byte offset in EC raw data + * @mul: correction factor to multiply by + * @add: correction term to add after multiplication + * @attr: battery attribute + * @buf: output buffer + * The 16-bit value is read from the EC, treated as signed, + * transformed as x->mul*x+add, and printed to the buffer. + */ +static ssize_t show_tp_ec_bat_s16(u8 arg0, int offset, int mul, int add, + struct device_attribute *attr, char *buf) +{ + u16 val; + int ret = get_tp_ec_bat_16(arg0, offset, attr_get_bat(attr), &val); + if (ret) + return ret; + return sprintf(buf, "%d\n", mul*(s16)val+add); +} + +/** + * show_tp_ec_bat_str - show a string from EC battery status data + * @arg0: specified 1st argument of EC raw to read + * @offset: byte offset in EC raw data + * @maxlen: maximum string length + * @attr: battery attribute + * @buf: output buffer + */ +static ssize_t show_tp_ec_bat_str(u8 arg0, int offset, int maxlen, + struct device_attribute *attr, char *buf) +{ + int bat = attr_get_bat(attr); + u8 row[TP_CONTROLLER_ROW_LEN]; + int ret; + if (bat_has_status(bat) != 1) + return -ENXIO; + ret = read_tp_ec_row(arg0, bat, 0, row); + if (ret) + return ret; + strncpy(buf, (char *)row+offset, maxlen); + buf[maxlen] = 0; + strcat(buf, "\n"); + return strlen(buf); +} + +/** + * show_tp_ec_bat_power - show a power readout from EC battery status data + * @arg0: specified 1st argument of EC raw to read + * @offV: byte offset of voltage in EC raw data + * @offI: byte offset of current in EC raw data + * @attr: battery attribute + * @buf: output buffer + * Computes the power as current*voltage from the two given readout offsets. + */ +static ssize_t show_tp_ec_bat_power(u8 arg0, int offV, int offI, + struct device_attribute *attr, char *buf) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + int milliamp, millivolt, ret; + int bat = attr_get_bat(attr); + if (bat_has_status(bat) != 1) + return -ENXIO; + ret = read_tp_ec_row(1, bat, 0, row); + if (ret) + return ret; + millivolt = *(u16 *)(row+offV); + milliamp = *(s16 *)(row+offI); + return sprintf(buf, "%d\n", milliamp*millivolt/1000); /* units: mW */ +} + +/** + * show_tp_ec_bat_date - decode and show a date from EC battery status data + * @arg0: specified 1st argument of EC raw to read + * @offset: byte offset in EC raw data + * @attr: battery attribute + * @buf: output buffer + */ +static ssize_t show_tp_ec_bat_date(u8 arg0, int offset, + struct device_attribute *attr, char *buf) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + u16 v; + int ret; + int day, month, year; + int bat = attr_get_bat(attr); + if (bat_has_status(bat) != 1) + return -ENXIO; + ret = read_tp_ec_row(arg0, bat, 0, row); + if (ret) + return ret; + + /* Decode bit-packed: v = day | (month<<5) | ((year-1980)<<9) */ + v = *(u16 *)(row+offset); + day = v & 0x1F; + month = (v >> 5) & 0xF; + year = (v >> 9) + 1980; + + return sprintf(buf, "%04d-%02d-%02d\n", year, month, day); +} + + +/********************************************************************* + * sysfs attribute I/O for batteries - + * the actual attribute show/store functions + */ + +static ssize_t show_battery_start_charge_thresh(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int thresh; + int bat = attr_get_bat(attr); + int ret = get_thresh(bat, THRESH_START, &thresh); + if (ret) + return ret; + return sprintf(buf, "%d\n", thresh); /* units: percent */ +} + +static ssize_t show_battery_stop_charge_thresh(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int thresh; + int bat = attr_get_bat(attr); + int ret = get_thresh(bat, THRESH_STOP, &thresh); + if (ret) + return ret; + return sprintf(buf, "%d\n", thresh); /* units: percent */ +} + +/** + * store_battery_start_charge_thresh - store battery_start_charge_thresh attr + * Since this is a kernel<->user interface, we ensure a valid state for + * the hardware. We do this by clamping the requested threshold to the + * valid range and, if necessary, moving the other threshold so that + * it's MIN_THRESH_DELTA away from this one. + */ +static ssize_t store_battery_start_charge_thresh(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + int thresh, other_thresh, ret; + int bat = attr_get_bat(attr); + + if (sscanf(buf, "%d", &thresh) != 1 || thresh < 1 || thresh > 100) + return -EINVAL; + + if (thresh < MIN_THRESH_START) /* clamp up to MIN_THRESH_START */ + thresh = MIN_THRESH_START; + if (thresh > MAX_THRESH_START) /* clamp down to MAX_THRESH_START */ + thresh = MAX_THRESH_START; + + down(&smapi_mutex); + ret = get_thresh(bat, THRESH_STOP, &other_thresh); + if (ret != -EOPNOTSUPP && ret != -ENXIO) { + if (ret) /* other threshold is set? */ + goto out; + ret = get_real_thresh(bat, THRESH_START, NULL); + if (ret) /* this threshold is set? */ + goto out; + if (other_thresh < thresh+MIN_THRESH_DELTA) { + /* move other thresh to keep it above this one */ + ret = set_thresh(bat, THRESH_STOP, + thresh+MIN_THRESH_DELTA); + if (ret) + goto out; + } + } + ret = set_thresh(bat, THRESH_START, thresh); +out: + up(&smapi_mutex); + return count; + +} + +/** + * store_battery_stop_charge_thresh - store battery_stop_charge_thresh attr + * Since this is a kernel<->user interface, we ensure a valid state for + * the hardware. We do this by clamping the requested threshold to the + * valid range and, if necessary, moving the other threshold so that + * it's MIN_THRESH_DELTA away from this one. + */ +static ssize_t store_battery_stop_charge_thresh(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + int thresh, other_thresh, ret; + int bat = attr_get_bat(attr); + + if (sscanf(buf, "%d", &thresh) != 1 || thresh < 1 || thresh > 100) + return -EINVAL; + + if (thresh < MIN_THRESH_STOP) /* clamp up to MIN_THRESH_STOP */ + thresh = MIN_THRESH_STOP; + + down(&smapi_mutex); + ret = get_thresh(bat, THRESH_START, &other_thresh); + if (ret != -EOPNOTSUPP && ret != -ENXIO) { /* other threshold exists? */ + if (ret) + goto out; + /* this threshold exists? */ + ret = get_real_thresh(bat, THRESH_STOP, NULL); + if (ret) + goto out; + if (other_thresh >= thresh-MIN_THRESH_DELTA) { + /* move other thresh to be below this one */ + ret = set_thresh(bat, THRESH_START, + thresh-MIN_THRESH_DELTA); + if (ret) + goto out; + } + } + ret = set_thresh(bat, THRESH_STOP, thresh); +out: + up(&smapi_mutex); + return count; +} + +static ssize_t show_battery_inhibit_charge_minutes(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int minutes; + int bat = attr_get_bat(attr); + int ret = get_inhibit_charge_minutes(bat, &minutes); + if (ret) + return ret; + return sprintf(buf, "%d\n", minutes); /* units: minutes */ +} + +static ssize_t store_battery_inhibit_charge_minutes(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int ret; + int minutes; + int bat = attr_get_bat(attr); + if (sscanf(buf, "%d", &minutes) != 1 || minutes < 0) { + TPRINTK(KERN_ERR, "inhibit_charge_minutes: " + "must be a non-negative integer"); + return -EINVAL; + } + ret = set_inhibit_charge_minutes(bat, minutes); + if (ret) + return ret; + return count; +} + +static ssize_t show_battery_force_discharge(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int enabled; + int bat = attr_get_bat(attr); + int ret = get_force_discharge(bat, &enabled); + if (ret) + return ret; + return sprintf(buf, "%d\n", enabled); /* type: boolean */ +} + +static ssize_t store_battery_force_discharge(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + int ret; + int enabled; + int bat = attr_get_bat(attr); + if (sscanf(buf, "%d", &enabled) != 1 || enabled < 0 || enabled > 1) + return -EINVAL; + ret = set_force_discharge(bat, enabled); + if (ret) + return ret; + return count; +} + +static ssize_t show_battery_installed( + struct device *dev, struct device_attribute *attr, char *buf) +{ + int bat = attr_get_bat(attr); + int ret = power_device_present(bat); + if (ret < 0) + return ret; + return sprintf(buf, "%d\n", ret); /* type: boolean */ +} + +static ssize_t show_battery_state( + struct device *dev, struct device_attribute *attr, char *buf) +{ + u8 row[TP_CONTROLLER_ROW_LEN]; + const char *txt; + int ret; + int bat = attr_get_bat(attr); + if (bat_has_status(bat) != 1) + return sprintf(buf, "none\n"); + ret = read_tp_ec_row(1, bat, 0, row); + if (ret) + return ret; + switch (row[1] & 0xf0) { + case 0xc0: txt = "idle"; break; + case 0xd0: txt = "discharging"; break; + case 0xe0: txt = "charging"; break; + default: return sprintf(buf, "unknown (0x%x)\n", row[1]); + } + return sprintf(buf, "%s\n", txt); /* type: string from fixed set */ +} + +static ssize_t show_battery_manufacturer( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: string. SBS spec v1.1 p34: ManufacturerName() */ + return show_tp_ec_bat_str(4, 2, TP_CONTROLLER_ROW_LEN-2, attr, buf); +} + +static ssize_t show_battery_model( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: string. SBS spec v1.1 p34: DeviceName() */ + return show_tp_ec_bat_str(5, 2, TP_CONTROLLER_ROW_LEN-2, attr, buf); +} + +static ssize_t show_battery_barcoding( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: string */ + return show_tp_ec_bat_str(7, 2, TP_CONTROLLER_ROW_LEN-2, attr, buf); +} + +static ssize_t show_battery_chemistry( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: string. SBS spec v1.1 p34-35: DeviceChemistry() */ + return show_tp_ec_bat_str(6, 2, 5, attr, buf); +} + +static ssize_t show_battery_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV. SBS spec v1.1 p24: Voltage() */ + return show_tp_ec_bat_u16(1, 6, 1, NULL, attr, buf); +} + +static ssize_t show_battery_design_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV. SBS spec v1.1 p32: DesignVoltage() */ + return show_tp_ec_bat_u16(3, 4, 1, NULL, attr, buf); +} + +static ssize_t show_battery_charging_max_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV. SBS spec v1.1 p37,39: ChargingVoltage() */ + return show_tp_ec_bat_u16(9, 8, 1, NULL, attr, buf); +} + +static ssize_t show_battery_group0_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV */ + return show_tp_ec_bat_u16(0xA, 12, 1, NULL, attr, buf); +} + +static ssize_t show_battery_group1_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV */ + return show_tp_ec_bat_u16(0xA, 10, 1, NULL, attr, buf); +} + +static ssize_t show_battery_group2_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV */ + return show_tp_ec_bat_u16(0xA, 8, 1, NULL, attr, buf); +} + +static ssize_t show_battery_group3_voltage( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mV */ + return show_tp_ec_bat_u16(0xA, 6, 1, NULL, attr, buf); +} + +static ssize_t show_battery_current_now( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mA. SBS spec v1.1 p24: Current() */ + return show_tp_ec_bat_s16(1, 8, 1, 0, attr, buf); +} + +static ssize_t show_battery_current_avg( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mA. SBS spec v1.1 p24: AverageCurrent() */ + return show_tp_ec_bat_s16(1, 10, 1, 0, attr, buf); +} + +static ssize_t show_battery_charging_max_current( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mA. SBS spec v1.1 p36,38: ChargingCurrent() */ + return show_tp_ec_bat_s16(9, 6, 1, 0, attr, buf); +} + +static ssize_t show_battery_power_now( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mW. SBS spec v1.1: Voltage()*Current() */ + return show_tp_ec_bat_power(1, 6, 8, attr, buf); +} + +static ssize_t show_battery_power_avg( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mW. SBS spec v1.1: Voltage()*AverageCurrent() */ + return show_tp_ec_bat_power(1, 6, 10, attr, buf); +} + +static ssize_t show_battery_remaining_percent( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: percent. SBS spec v1.1 p25: RelativeStateOfCharge() */ + return show_tp_ec_bat_u16(1, 12, 1, NULL, attr, buf); +} + +static ssize_t show_battery_remaining_percent_error( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: percent. SBS spec v1.1 p25: MaxError() */ + return show_tp_ec_bat_u16(9, 4, 1, NULL, attr, buf); +} + +static ssize_t show_battery_remaining_charging_time( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: minutes. SBS spec v1.1 p27: AverageTimeToFull() */ + return show_tp_ec_bat_u16(2, 8, 1, "not_charging", attr, buf); +} + +static ssize_t show_battery_remaining_running_time( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: minutes. SBS spec v1.1 p27: RunTimeToEmpty() */ + return show_tp_ec_bat_u16(2, 6, 1, "not_discharging", attr, buf); +} + +static ssize_t show_battery_remaining_running_time_now( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: minutes. SBS spec v1.1 p27: RunTimeToEmpty() */ + return show_tp_ec_bat_u16(2, 4, 1, "not_discharging", attr, buf); +} + +static ssize_t show_battery_remaining_capacity( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mWh. SBS spec v1.1 p26. */ + return show_tp_ec_bat_u16(1, 14, 10, "", attr, buf); +} + +static ssize_t show_battery_last_full_capacity( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mWh. SBS spec v1.1 p26: FullChargeCapacity() */ + return show_tp_ec_bat_u16(2, 2, 10, "", attr, buf); +} + +static ssize_t show_battery_design_capacity( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: mWh. SBS spec v1.1 p32: DesignCapacity() */ + return show_tp_ec_bat_u16(3, 2, 10, "", attr, buf); +} + +static ssize_t show_battery_cycle_count( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: ordinal. SBS spec v1.1 p32: CycleCount() */ + return show_tp_ec_bat_u16(2, 12, 1, "", attr, buf); +} + +static ssize_t show_battery_temperature( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* units: millicelsius. SBS spec v1.1: Temperature()*10 */ + return show_tp_ec_bat_s16(1, 4, 100, -273100, attr, buf); +} + +static ssize_t show_battery_serial( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: int. SBS spec v1.1 p34: SerialNumber() */ + return show_tp_ec_bat_u16(3, 10, 1, "", attr, buf); +} + +static ssize_t show_battery_manufacture_date( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: YYYY-MM-DD. SBS spec v1.1 p34: ManufactureDate() */ + return show_tp_ec_bat_date(3, 8, attr, buf); +} + +static ssize_t show_battery_first_use_date( + struct device *dev, struct device_attribute *attr, char *buf) +{ + /* type: YYYY-MM-DD */ + return show_tp_ec_bat_date(8, 2, attr, buf); +} + +/** + * show_battery_dump - show the battery's dump attribute + * The dump attribute gives a hex dump of all EC readouts related to a + * battery. Some of the enumerated values don't really exist (i.e., the + * EC function just leaves them untouched); we use a kludge to detect and + * denote these. + */ +#define MIN_DUMP_ARG0 0x00 +#define MAX_DUMP_ARG0 0x0a /* 0x0b is useful too but hangs old EC firmware */ +static ssize_t show_battery_dump( + struct device *dev, struct device_attribute *attr, char *buf) +{ + int i; + char *p = buf; + int bat = attr_get_bat(attr); + u8 arg0; /* first argument to EC */ + u8 rowa[TP_CONTROLLER_ROW_LEN], + rowb[TP_CONTROLLER_ROW_LEN]; + const u8 junka = 0xAA, + junkb = 0x55; /* junk values for testing changes */ + int ret; + + for (arg0 = MIN_DUMP_ARG0; arg0 <= MAX_DUMP_ARG0; ++arg0) { + if ((p-buf) > PAGE_SIZE-TP_CONTROLLER_ROW_LEN*5) + return -ENOMEM; /* don't overflow sysfs buf */ + /* Read raw twice with different junk values, + * to detect unused output bytes which are left unchaged: */ + ret = read_tp_ec_row(arg0, bat, junka, rowa); + if (ret) + return ret; + ret = read_tp_ec_row(arg0, bat, junkb, rowb); + if (ret) + return ret; + for (i = 0; i < TP_CONTROLLER_ROW_LEN; i++) { + if (rowa[i] == junka && rowb[i] == junkb) + p += sprintf(p, "-- "); /* unused by EC */ + else + p += sprintf(p, "%02x ", rowa[i]); + } + p += sprintf(p, "\n"); + } + return p-buf; +} + + +/********************************************************************* + * sysfs attribute I/O, other than batteries + */ + +static ssize_t show_ac_connected( + struct device *dev, struct device_attribute *attr, char *buf) +{ + int ret = power_device_present(0xFF); + if (ret < 0) + return ret; + return sprintf(buf, "%d\n", ret); /* type: boolean */ +} + +/********************************************************************* + * The the "smapi_request" sysfs attribute executes a raw SMAPI call. + * You write to make a request and read to get the result. The state + * is saved globally rather than per fd (sysfs limitation), so + * simultaenous requests may get each other's results! So this is for + * development and debugging only. + */ +#define MAX_SMAPI_ATTR_ANSWER_LEN 128 +static char smapi_attr_answer[MAX_SMAPI_ATTR_ANSWER_LEN] = ""; + +static ssize_t show_smapi_request(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret = snprintf(buf, PAGE_SIZE, "%s", smapi_attr_answer); + smapi_attr_answer[0] = '\0'; + return ret; +} + +static ssize_t store_smapi_request(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned int inEBX, inECX, inEDI, inESI; + u32 outEBX, outECX, outEDX, outEDI, outESI; + const char *msg; + int ret; + if (sscanf(buf, "%x %x %x %x", &inEBX, &inECX, &inEDI, &inESI) != 4) { + smapi_attr_answer[0] = '\0'; + return -EINVAL; + } + ret = smapi_request( + inEBX, inECX, inEDI, inESI, + &outEBX, &outECX, &outEDX, &outEDI, &outESI, &msg); + snprintf(smapi_attr_answer, MAX_SMAPI_ATTR_ANSWER_LEN, + "%x %x %x %x %x %d '%s'\n", + (unsigned int)outEBX, (unsigned int)outECX, + (unsigned int)outEDX, (unsigned int)outEDI, + (unsigned int)outESI, ret, msg); + if (ret) + return ret; + else + return count; +} + +/********************************************************************* + * Power management: the embedded controller forgets the battery + * thresholds when the system is suspended to disk and unplugged from + * AC and battery, so we restore it upon resume. + */ + +static int saved_threshs[4] = {-1, -1, -1, -1}; /* -1 = don't know */ + +static int tp_suspend(struct platform_device *dev, pm_message_t state) +{ + int restore = (state.event == PM_EVENT_HIBERNATE || + state.event == PM_EVENT_FREEZE); + if (!restore || get_real_thresh(0, THRESH_STOP , &saved_threshs[0])) + saved_threshs[0] = -1; + if (!restore || get_real_thresh(0, THRESH_START, &saved_threshs[1])) + saved_threshs[1] = -1; + if (!restore || get_real_thresh(1, THRESH_STOP , &saved_threshs[2])) + saved_threshs[2] = -1; + if (!restore || get_real_thresh(1, THRESH_START, &saved_threshs[3])) + saved_threshs[3] = -1; + DPRINTK("suspend saved: %d %d %d %d", saved_threshs[0], + saved_threshs[1], saved_threshs[2], saved_threshs[3]); + return 0; +} + +static int tp_resume(struct platform_device *dev) +{ + DPRINTK("resume restoring: %d %d %d %d", saved_threshs[0], + saved_threshs[1], saved_threshs[2], saved_threshs[3]); + if (saved_threshs[0] >= 0) + set_real_thresh(0, THRESH_STOP , saved_threshs[0]); + if (saved_threshs[1] >= 0) + set_real_thresh(0, THRESH_START, saved_threshs[1]); + if (saved_threshs[2] >= 0) + set_real_thresh(1, THRESH_STOP , saved_threshs[2]); + if (saved_threshs[3] >= 0) + set_real_thresh(1, THRESH_START, saved_threshs[3]); + return 0; +} + + +/********************************************************************* + * Driver model + */ + +static struct platform_driver tp_driver = { + .suspend = tp_suspend, + .resume = tp_resume, + .driver = { + .name = "smapi", + .owner = THIS_MODULE + }, +}; + + +/********************************************************************* + * Sysfs device model + */ + +/* Attributes in /sys/devices/platform/smapi/ */ + +static DEVICE_ATTR(ac_connected, 0444, show_ac_connected, NULL); +static DEVICE_ATTR(smapi_request, 0600, show_smapi_request, + store_smapi_request); + +static struct attribute *tp_root_attributes[] = { + &dev_attr_ac_connected.attr, + &dev_attr_smapi_request.attr, + NULL +}; +static struct attribute_group tp_root_attribute_group = { + .attrs = tp_root_attributes +}; + +/* Attributes under /sys/devices/platform/smapi/BAT{0,1}/ : + * Every attribute needs to be defined (i.e., statically allocated) for + * each battery, and then referenced in the attribute list of each battery. + * We use preprocessor voodoo to avoid duplicating the list of attributes 4 + * times. The preprocessor output is just normal sysfs attributes code. + */ + +/** + * FOREACH_BAT_ATTR - invoke the given macros on all our battery attributes + * @_BAT: battery number (0 or 1) + * @_ATTR_RW: macro to invoke for each read/write attribute + * @_ATTR_R: macro to invoke for each read-only attribute + */ +#define FOREACH_BAT_ATTR(_BAT, _ATTR_RW, _ATTR_R) \ + _ATTR_RW(_BAT, start_charge_thresh) \ + _ATTR_RW(_BAT, stop_charge_thresh) \ + _ATTR_RW(_BAT, inhibit_charge_minutes) \ + _ATTR_RW(_BAT, force_discharge) \ + _ATTR_R(_BAT, installed) \ + _ATTR_R(_BAT, state) \ + _ATTR_R(_BAT, manufacturer) \ + _ATTR_R(_BAT, model) \ + _ATTR_R(_BAT, barcoding) \ + _ATTR_R(_BAT, chemistry) \ + _ATTR_R(_BAT, voltage) \ + _ATTR_R(_BAT, group0_voltage) \ + _ATTR_R(_BAT, group1_voltage) \ + _ATTR_R(_BAT, group2_voltage) \ + _ATTR_R(_BAT, group3_voltage) \ + _ATTR_R(_BAT, current_now) \ + _ATTR_R(_BAT, current_avg) \ + _ATTR_R(_BAT, charging_max_current) \ + _ATTR_R(_BAT, power_now) \ + _ATTR_R(_BAT, power_avg) \ + _ATTR_R(_BAT, remaining_percent) \ + _ATTR_R(_BAT, remaining_percent_error) \ + _ATTR_R(_BAT, remaining_charging_time) \ + _ATTR_R(_BAT, remaining_running_time) \ + _ATTR_R(_BAT, remaining_running_time_now) \ + _ATTR_R(_BAT, remaining_capacity) \ + _ATTR_R(_BAT, last_full_capacity) \ + _ATTR_R(_BAT, design_voltage) \ + _ATTR_R(_BAT, charging_max_voltage) \ + _ATTR_R(_BAT, design_capacity) \ + _ATTR_R(_BAT, cycle_count) \ + _ATTR_R(_BAT, temperature) \ + _ATTR_R(_BAT, serial) \ + _ATTR_R(_BAT, manufacture_date) \ + _ATTR_R(_BAT, first_use_date) \ + _ATTR_R(_BAT, dump) + +/* Define several macros we will feed into FOREACH_BAT_ATTR: */ + +#define DEFINE_BAT_ATTR_RW(_BAT,_NAME) \ + static struct bat_device_attribute dev_attr_##_NAME##_##_BAT = { \ + .dev_attr = __ATTR(_NAME, 0644, show_battery_##_NAME, \ + store_battery_##_NAME), \ + .bat = _BAT \ + }; + +#define DEFINE_BAT_ATTR_R(_BAT,_NAME) \ + static struct bat_device_attribute dev_attr_##_NAME##_##_BAT = { \ + .dev_attr = __ATTR(_NAME, 0644, show_battery_##_NAME, 0), \ + .bat = _BAT \ + }; + +#define REF_BAT_ATTR(_BAT,_NAME) \ + &dev_attr_##_NAME##_##_BAT.dev_attr.attr, + +/* This provide all attributes for one battery: */ + +#define PROVIDE_BAT_ATTRS(_BAT) \ + FOREACH_BAT_ATTR(_BAT, DEFINE_BAT_ATTR_RW, DEFINE_BAT_ATTR_R) \ + static struct attribute *tp_bat##_BAT##_attributes[] = { \ + FOREACH_BAT_ATTR(_BAT, REF_BAT_ATTR, REF_BAT_ATTR) \ + NULL \ + }; \ + static struct attribute_group tp_bat##_BAT##_attribute_group = { \ + .name = "BAT" #_BAT, \ + .attrs = tp_bat##_BAT##_attributes \ + }; + +/* Finally genereate the attributes: */ + +PROVIDE_BAT_ATTRS(0) +PROVIDE_BAT_ATTRS(1) + +/* List of attribute groups */ + +static struct attribute_group *attr_groups[] = { + &tp_root_attribute_group, + &tp_bat0_attribute_group, + &tp_bat1_attribute_group, + NULL +}; + + +/********************************************************************* + * Init and cleanup + */ + +static struct attribute_group **next_attr_group; /* next to register */ + +static int __init tp_init(void) +{ + int ret; + printk(KERN_INFO "tp_smapi " TP_VERSION " loading...\n"); + + ret = find_smapi_port(); + if (ret < 0) + goto err; + else + smapi_port = ret; + + if (!request_region(smapi_port, 1, "smapi")) { + printk(KERN_ERR "tp_smapi cannot claim port 0x%x\n", + smapi_port); + ret = -ENXIO; + goto err; + } + + if (!request_region(SMAPI_PORT2, 1, "smapi")) { + printk(KERN_ERR "tp_smapi cannot claim port 0x%x\n", + SMAPI_PORT2); + ret = -ENXIO; + goto err_port1; + } + + ret = platform_driver_register(&tp_driver); + if (ret) + goto err_port2; + + pdev = platform_device_alloc("smapi", -1); + if (!pdev) { + ret = -ENOMEM; + goto err_driver; + } + + ret = platform_device_add(pdev); + if (ret) + goto err_device_free; + + for (next_attr_group = attr_groups; *next_attr_group; + ++next_attr_group) { + ret = sysfs_create_group(&pdev->dev.kobj, *next_attr_group); + if (ret) + goto err_attr; + } + + printk(KERN_INFO "tp_smapi successfully loaded (smapi_port=0x%x).\n", + smapi_port); + return 0; + +err_attr: + while (--next_attr_group >= attr_groups) + sysfs_remove_group(&pdev->dev.kobj, *next_attr_group); + platform_device_unregister(pdev); +err_device_free: + platform_device_put(pdev); +err_driver: + platform_driver_unregister(&tp_driver); +err_port2: + release_region(SMAPI_PORT2, 1); +err_port1: + release_region(smapi_port, 1); +err: + printk(KERN_ERR "tp_smapi init failed (ret=%d)!\n", ret); + return ret; +} + +static void __exit tp_exit(void) +{ + while (next_attr_group && --next_attr_group >= attr_groups) + sysfs_remove_group(&pdev->dev.kobj, *next_attr_group); + platform_device_unregister(pdev); + platform_driver_unregister(&tp_driver); + release_region(SMAPI_PORT2, 1); + if (smapi_port) + release_region(smapi_port, 1); + + printk(KERN_INFO "tp_smapi unloaded.\n"); +} + +module_init(tp_init); +module_exit(tp_exit); diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig index d145e0d..4a62250 100644 --- a/drivers/scsi/Kconfig +++ b/drivers/scsi/Kconfig @@ -1613,4 +1613,6 @@ source "drivers/scsi/device_handler/Kconfig" source "drivers/scsi/osd/Kconfig" +source "drivers/scsi/vhba/Kconfig" + endmenu diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile index 93dbe58..0d83856 100644 --- a/drivers/scsi/Makefile +++ b/drivers/scsi/Makefile @@ -154,6 +154,7 @@ obj-$(CONFIG_SCSI_ENCLOSURE) += ses.o obj-$(CONFIG_SCSI_OSD_INITIATOR) += osd/ obj-$(CONFIG_SCSI_HISI_SAS) += hisi_sas/ +obj-$(CONFIG_VHBA) += vhba/ # This goes last, so that "real" scsi devices probe earlier obj-$(CONFIG_SCSI_DEBUG) += scsi_debug.o diff --git b/drivers/scsi/vhba/Kconfig b/drivers/scsi/vhba/Kconfig new file mode 100644 index 0000000..7ccb7d8 --- /dev/null +++ b/drivers/scsi/vhba/Kconfig @@ -0,0 +1,9 @@ +config VHBA + tristate "Virtual (SCSI) Host Bus Adapter" + depends on SCSI + ---help--- + This is the in-kernel part of CDEmu, a CD/DVD-ROM device + emulator. + + This driver can also be built as a module. If so, the module + will be called vhba. diff --git b/drivers/scsi/vhba/Makefile b/drivers/scsi/vhba/Makefile new file mode 100644 index 0000000..a2a3f9d --- /dev/null +++ b/drivers/scsi/vhba/Makefile @@ -0,0 +1,4 @@ +VHBA_VERSION := 20170610 + +obj-$(CONFIG_VHBA) += vhba.o +ccflags-y := -DVHBA_VERSION=\"$(VHBA_VERSION)\" -Werror diff --git b/drivers/scsi/vhba/vhba.c b/drivers/scsi/vhba/vhba.c new file mode 100644 index 0000000..ff30e4c --- /dev/null +++ b/drivers/scsi/vhba/vhba.c @@ -0,0 +1,1076 @@ +/* + * vhba.c + * + * Copyright (C) 2007-2012 Chia-I Wu + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include + +#include +#include +#include +#include +#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0) +#include +#else +#include +#endif +#include +#include +#include +#include +#ifdef CONFIG_COMPAT +#include +#endif +#include +#include +#include +#include +#include + +/* scatterlist.page_link and sg_page() were introduced in 2.6.24 */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24) +#define USE_SG_PAGE +#include +#endif + +MODULE_AUTHOR("Chia-I Wu"); +MODULE_VERSION(VHBA_VERSION); +MODULE_DESCRIPTION("Virtual SCSI HBA"); +MODULE_LICENSE("GPL"); + +#ifdef DEBUG +#define DPRINTK(fmt, args...) printk(KERN_DEBUG "%s: " fmt, __FUNCTION__, ## args) +#else +#define DPRINTK(fmt, args...) +#endif + +/* scmd_dbg was introduced in 3.15 */ +#ifndef scmd_dbg +#define scmd_dbg(scmd, fmt, a...) \ + dev_dbg(&(scmd)->device->sdev_gendev, fmt, ##a) +#endif + +#ifndef scmd_warn +#define scmd_warn(scmd, fmt, a...) \ + dev_warn(&(scmd)->device->sdev_gendev, fmt, ##a) +#endif + +#define VHBA_MAX_SECTORS_PER_IO 256 +#define VHBA_MAX_ID 32 +#define VHBA_CAN_QUEUE 32 +#define VHBA_INVALID_ID VHBA_MAX_ID + +#define DATA_TO_DEVICE(dir) ((dir) == DMA_TO_DEVICE || (dir) == DMA_BIDIRECTIONAL) +#define DATA_FROM_DEVICE(dir) ((dir) == DMA_FROM_DEVICE || (dir) == DMA_BIDIRECTIONAL) + + +/* SCSI macros were introduced in 2.6.23 */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 23) +#define scsi_sg_count(cmd) ((cmd)->use_sg) +#define scsi_sglist(cmd) ((cmd)->request_buffer) +#define scsi_bufflen(cmd) ((cmd)->request_bufflen) +#define scsi_set_resid(cmd, to_read) {(cmd)->resid = (to_read);} +#endif + +/* 1-argument form of k[un]map_atomic was introduced in 2.6.37-rc1; + 2-argument form was deprecated in 3.4-rc1 */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 37) +#define vhba_kmap_atomic kmap_atomic +#define vhba_kunmap_atomic kunmap_atomic +#else +#define vhba_kmap_atomic(page) kmap_atomic(page, KM_USER0) +#define vhba_kunmap_atomic(page) kunmap_atomic(page, KM_USER0) +#endif + + +enum vhba_req_state { + VHBA_REQ_FREE, + VHBA_REQ_PENDING, + VHBA_REQ_READING, + VHBA_REQ_SENT, + VHBA_REQ_WRITING, +}; + +struct vhba_command { + struct scsi_cmnd *cmd; + int status; + struct list_head entry; +}; + +struct vhba_device { + uint id; + spinlock_t cmd_lock; + struct list_head cmd_list; + wait_queue_head_t cmd_wq; + atomic_t refcnt; +}; + +struct vhba_host { + struct Scsi_Host *shost; + spinlock_t cmd_lock; + int cmd_next; + struct vhba_command commands[VHBA_CAN_QUEUE]; + spinlock_t dev_lock; + struct vhba_device *devices[VHBA_MAX_ID]; + int num_devices; + DECLARE_BITMAP(chgmap, VHBA_MAX_ID); + int chgtype[VHBA_MAX_ID]; + struct work_struct scan_devices; +}; + +#define MAX_COMMAND_SIZE 16 + +struct vhba_request { + __u32 tag; + __u32 lun; + __u8 cdb[MAX_COMMAND_SIZE]; + __u8 cdb_len; + __u32 data_len; +}; + +struct vhba_response { + __u32 tag; + __u32 status; + __u32 data_len; +}; + +static struct vhba_command *vhba_alloc_command (void); +static void vhba_free_command (struct vhba_command *vcmd); + +static struct platform_device vhba_platform_device; + +static struct vhba_device *vhba_device_alloc (void) +{ + struct vhba_device *vdev; + + vdev = kzalloc(sizeof(struct vhba_device), GFP_KERNEL); + if (!vdev) { + return NULL; + } + + vdev->id = VHBA_INVALID_ID; + spin_lock_init(&vdev->cmd_lock); + INIT_LIST_HEAD(&vdev->cmd_list); + init_waitqueue_head(&vdev->cmd_wq); + atomic_set(&vdev->refcnt, 1); + + return vdev; +} + +static void vhba_device_put (struct vhba_device *vdev) +{ + if (atomic_dec_and_test(&vdev->refcnt)) { + kfree(vdev); + } +} + +static struct vhba_device *vhba_device_get (struct vhba_device *vdev) +{ + atomic_inc(&vdev->refcnt); + + return vdev; +} + +static int vhba_device_queue (struct vhba_device *vdev, struct scsi_cmnd *cmd) +{ + struct vhba_command *vcmd; + unsigned long flags; + + vcmd = vhba_alloc_command(); + if (!vcmd) { + return SCSI_MLQUEUE_HOST_BUSY; + } + + vcmd->cmd = cmd; + + spin_lock_irqsave(&vdev->cmd_lock, flags); + list_add_tail(&vcmd->entry, &vdev->cmd_list); + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + wake_up_interruptible(&vdev->cmd_wq); + + return 0; +} + +static int vhba_device_dequeue (struct vhba_device *vdev, struct scsi_cmnd *cmd) +{ + struct vhba_command *vcmd; + int retval; + unsigned long flags; + + spin_lock_irqsave(&vdev->cmd_lock, flags); + list_for_each_entry(vcmd, &vdev->cmd_list, entry) { + if (vcmd->cmd == cmd) { + list_del_init(&vcmd->entry); + break; + } + } + + /* command not found */ + if (&vcmd->entry == &vdev->cmd_list) { + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + return SUCCESS; + } + + while (vcmd->status == VHBA_REQ_READING || vcmd->status == VHBA_REQ_WRITING) { + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + scmd_dbg(cmd, "wait for I/O before aborting\n"); + schedule_timeout(1); + spin_lock_irqsave(&vdev->cmd_lock, flags); + } + + retval = (vcmd->status == VHBA_REQ_SENT) ? FAILED : SUCCESS; + + vhba_free_command(vcmd); + + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + return retval; +} + +static inline void vhba_scan_devices_add (struct vhba_host *vhost, int id) +{ + struct scsi_device *sdev; + + sdev = scsi_device_lookup(vhost->shost, 0, id, 0); + if (!sdev) { + scsi_add_device(vhost->shost, 0, id, 0); + } else { + dev_warn(&vhost->shost->shost_gendev, "tried to add an already-existing device 0:%d:0!\n", id); + scsi_device_put(sdev); + } +} + +static inline void vhba_scan_devices_remove (struct vhba_host *vhost, int id) +{ + struct scsi_device *sdev; + + sdev = scsi_device_lookup(vhost->shost, 0, id, 0); + if (sdev) { + scsi_remove_device(sdev); + scsi_device_put(sdev); + } else { + dev_warn(&vhost->shost->shost_gendev, "tried to remove non-existing device 0:%d:0!\n", id); + } +} + +static void vhba_scan_devices (struct work_struct *work) +{ + struct vhba_host *vhost = container_of(work, struct vhba_host, scan_devices); + unsigned long flags; + int id, change, exists; + + while (1) { + spin_lock_irqsave(&vhost->dev_lock, flags); + + id = find_first_bit(vhost->chgmap, vhost->shost->max_id); + if (id >= vhost->shost->max_id) { + spin_unlock_irqrestore(&vhost->dev_lock, flags); + break; + } + change = vhost->chgtype[id]; + exists = vhost->devices[id] != NULL; + + vhost->chgtype[id] = 0; + clear_bit(id, vhost->chgmap); + + spin_unlock_irqrestore(&vhost->dev_lock, flags); + + if (change < 0) { + dev_dbg(&vhost->shost->shost_gendev, "trying to remove target 0:%d:0\n", id); + vhba_scan_devices_remove(vhost, id); + } else if (change > 0) { + dev_dbg(&vhost->shost->shost_gendev, "trying to add target 0:%d:0\n", id); + vhba_scan_devices_add(vhost, id); + } else { + /* quick sequence of add/remove or remove/add; we determine + which one it was by checking if device structure exists */ + if (exists) { + /* remove followed by add: remove and (re)add */ + dev_dbg(&vhost->shost->shost_gendev, "trying to (re)add target 0:%d:0\n", id); + vhba_scan_devices_remove(vhost, id); + vhba_scan_devices_add(vhost, id); + } else { + /* add followed by remove: no-op */ + dev_dbg(&vhost->shost->shost_gendev, "no-op for target 0:%d:0\n", id); + } + } + } +} + +static int vhba_add_device (struct vhba_device *vdev) +{ + struct vhba_host *vhost; + int i; + unsigned long flags; + + vhost = platform_get_drvdata(&vhba_platform_device); + + vhba_device_get(vdev); + + spin_lock_irqsave(&vhost->dev_lock, flags); + if (vhost->num_devices >= vhost->shost->max_id) { + spin_unlock_irqrestore(&vhost->dev_lock, flags); + vhba_device_put(vdev); + return -EBUSY; + } + + for (i = 0; i < vhost->shost->max_id; i++) { + if (vhost->devices[i] == NULL) { + vdev->id = i; + vhost->devices[i] = vdev; + vhost->num_devices++; + set_bit(vdev->id, vhost->chgmap); + vhost->chgtype[vdev->id]++; + break; + } + } + spin_unlock_irqrestore(&vhost->dev_lock, flags); + + schedule_work(&vhost->scan_devices); + + return 0; +} + +static int vhba_remove_device (struct vhba_device *vdev) +{ + struct vhba_host *vhost; + unsigned long flags; + + vhost = platform_get_drvdata(&vhba_platform_device); + + spin_lock_irqsave(&vhost->dev_lock, flags); + set_bit(vdev->id, vhost->chgmap); + vhost->chgtype[vdev->id]--; + vhost->devices[vdev->id] = NULL; + vhost->num_devices--; + vdev->id = VHBA_INVALID_ID; + spin_unlock_irqrestore(&vhost->dev_lock, flags); + + vhba_device_put(vdev); + + schedule_work(&vhost->scan_devices); + + return 0; +} + +static struct vhba_device *vhba_lookup_device (int id) +{ + struct vhba_host *vhost; + struct vhba_device *vdev = NULL; + unsigned long flags; + + vhost = platform_get_drvdata(&vhba_platform_device); + + if (likely(id < vhost->shost->max_id)) { + spin_lock_irqsave(&vhost->dev_lock, flags); + vdev = vhost->devices[id]; + if (vdev) { + vdev = vhba_device_get(vdev); + } + + spin_unlock_irqrestore(&vhost->dev_lock, flags); + } + + return vdev; +} + +static struct vhba_command *vhba_alloc_command (void) +{ + struct vhba_host *vhost; + struct vhba_command *vcmd; + unsigned long flags; + int i; + + vhost = platform_get_drvdata(&vhba_platform_device); + + spin_lock_irqsave(&vhost->cmd_lock, flags); + + vcmd = vhost->commands + vhost->cmd_next++; + if (vcmd->status != VHBA_REQ_FREE) { + for (i = 0; i < vhost->shost->can_queue; i++) { + vcmd = vhost->commands + i; + + if (vcmd->status == VHBA_REQ_FREE) { + vhost->cmd_next = i + 1; + break; + } + } + + if (i == vhost->shost->can_queue) { + vcmd = NULL; + } + } + + if (vcmd) { + vcmd->status = VHBA_REQ_PENDING; + } + + vhost->cmd_next %= vhost->shost->can_queue; + + spin_unlock_irqrestore(&vhost->cmd_lock, flags); + + return vcmd; +} + +static void vhba_free_command (struct vhba_command *vcmd) +{ + struct vhba_host *vhost; + unsigned long flags; + + vhost = platform_get_drvdata(&vhba_platform_device); + + spin_lock_irqsave(&vhost->cmd_lock, flags); + vcmd->status = VHBA_REQ_FREE; + spin_unlock_irqrestore(&vhost->cmd_lock, flags); +} + +static int vhba_queuecommand_lck (struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)) +{ + struct vhba_device *vdev; + int retval; + + scmd_dbg(cmd, "queue %lu\n", cmd->serial_number); + + vdev = vhba_lookup_device(cmd->device->id); + if (!vdev) { + scmd_dbg(cmd, "no such device\n"); + + cmd->result = DID_NO_CONNECT << 16; + done(cmd); + + return 0; + } + + cmd->scsi_done = done; + retval = vhba_device_queue(vdev, cmd); + + vhba_device_put(vdev); + + return retval; +} + +#ifdef DEF_SCSI_QCMD +DEF_SCSI_QCMD(vhba_queuecommand) +#else +#define vhba_queuecommand vhba_queuecommand_lck +#endif + +static int vhba_abort (struct scsi_cmnd *cmd) +{ + struct vhba_device *vdev; + int retval = SUCCESS; + + scmd_warn(cmd, "abort %lu\n", cmd->serial_number); + + vdev = vhba_lookup_device(cmd->device->id); + if (vdev) { + retval = vhba_device_dequeue(vdev, cmd); + vhba_device_put(vdev); + } else { + cmd->result = DID_NO_CONNECT << 16; + } + + return retval; +} + +static struct scsi_host_template vhba_template = { + .module = THIS_MODULE, + .name = "vhba", + .proc_name = "vhba", + .queuecommand = vhba_queuecommand, + .eh_abort_handler = vhba_abort, + .can_queue = VHBA_CAN_QUEUE, + .this_id = -1, + .cmd_per_lun = 1, + .max_sectors = VHBA_MAX_SECTORS_PER_IO, + .sg_tablesize = 256, +}; + +static ssize_t do_request (struct scsi_cmnd *cmd, char __user *buf, size_t buf_len) +{ + struct vhba_request vreq; + ssize_t ret; + + scmd_dbg(cmd, "request %lu, cdb 0x%x, bufflen %d, use_sg %d\n", + cmd->serial_number, cmd->cmnd[0], scsi_bufflen(cmd), scsi_sg_count(cmd)); + + ret = sizeof(vreq); + if (DATA_TO_DEVICE(cmd->sc_data_direction)) { + ret += scsi_bufflen(cmd); + } + + if (ret > buf_len) { + scmd_warn(cmd, "buffer too small (%zd < %zd) for a request\n", buf_len, ret); + return -EIO; + } + + vreq.tag = cmd->serial_number; + vreq.lun = cmd->device->lun; + memcpy(vreq.cdb, cmd->cmnd, MAX_COMMAND_SIZE); + vreq.cdb_len = cmd->cmd_len; + vreq.data_len = scsi_bufflen(cmd); + + if (copy_to_user(buf, &vreq, sizeof(vreq))) { + return -EFAULT; + } + + if (DATA_TO_DEVICE(cmd->sc_data_direction) && vreq.data_len) { + buf += sizeof(vreq); + + if (scsi_sg_count(cmd)) { + unsigned char buf_stack[64]; + unsigned char *kaddr, *uaddr, *kbuf; + struct scatterlist *sg = scsi_sglist(cmd); + int i; + + uaddr = (unsigned char *) buf; + + if (vreq.data_len > 64) { + kbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); + } else { + kbuf = buf_stack; + } + + for (i = 0; i < scsi_sg_count(cmd); i++) { + size_t len = sg[i].length; + +#ifdef USE_SG_PAGE + kaddr = vhba_kmap_atomic(sg_page(&sg[i])); +#else + kaddr = vhba_kmap_atomic(sg[i].page); +#endif + memcpy(kbuf, kaddr + sg[i].offset, len); + vhba_kunmap_atomic(kaddr); + + if (copy_to_user(uaddr, kbuf, len)) { + if (kbuf != buf_stack) { + kfree(kbuf); + } + return -EFAULT; + } + uaddr += len; + } + + if (kbuf != buf_stack) { + kfree(kbuf); + } + } else { + if (copy_to_user(buf, scsi_sglist(cmd), vreq.data_len)) { + return -EFAULT; + } + } + } + + return ret; +} + +static ssize_t do_response (struct scsi_cmnd *cmd, const char __user *buf, size_t buf_len, struct vhba_response *res) +{ + ssize_t ret = 0; + + scmd_dbg(cmd, "response %lu, status %x, data len %d, use_sg %d\n", + cmd->serial_number, res->status, res->data_len, scsi_sg_count(cmd)); + + if (res->status) { + unsigned char sense_stack[SCSI_SENSE_BUFFERSIZE]; + + if (res->data_len > SCSI_SENSE_BUFFERSIZE) { + scmd_warn(cmd, "truncate sense (%d < %d)", SCSI_SENSE_BUFFERSIZE, res->data_len); + res->data_len = SCSI_SENSE_BUFFERSIZE; + } + + /* Copy via temporary buffer on stack in order to avoid problems + with PAX on grsecurity-enabled kernels */ + if (copy_from_user(sense_stack, buf, res->data_len)) { + return -EFAULT; + } + memcpy(cmd->sense_buffer, sense_stack, res->data_len); + + cmd->result = res->status; + + ret += res->data_len; + } else if (DATA_FROM_DEVICE(cmd->sc_data_direction) && scsi_bufflen(cmd)) { + size_t to_read; + + if (res->data_len > scsi_bufflen(cmd)) { + scmd_warn(cmd, "truncate data (%d < %d)\n", scsi_bufflen(cmd), res->data_len); + res->data_len = scsi_bufflen(cmd); + } + + to_read = res->data_len; + + if (scsi_sg_count(cmd)) { + unsigned char buf_stack[64]; + unsigned char *kaddr, *uaddr, *kbuf; + struct scatterlist *sg = scsi_sglist(cmd); + int i; + + uaddr = (unsigned char *)buf; + + if (res->data_len > 64) { + kbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); + } else { + kbuf = buf_stack; + } + + for (i = 0; i < scsi_sg_count(cmd); i++) { + size_t len = (sg[i].length < to_read) ? sg[i].length : to_read; + + if (copy_from_user(kbuf, uaddr, len)) { + if (kbuf != buf_stack) { + kfree(kbuf); + } + return -EFAULT; + } + uaddr += len; + +#ifdef USE_SG_PAGE + kaddr = vhba_kmap_atomic(sg_page(&sg[i])); +#else + kaddr = vhba_kmap_atomic(sg[i].page); +#endif + memcpy(kaddr + sg[i].offset, kbuf, len); + vhba_kunmap_atomic(kaddr); + + to_read -= len; + if (to_read == 0) { + break; + } + } + + if (kbuf != buf_stack) { + kfree(kbuf); + } + } else { + if (copy_from_user(scsi_sglist(cmd), buf, res->data_len)) { + return -EFAULT; + } + + to_read -= res->data_len; + } + + scsi_set_resid(cmd, to_read); + + ret += res->data_len - to_read; + } + + return ret; +} + +static inline struct vhba_command *next_command (struct vhba_device *vdev) +{ + struct vhba_command *vcmd; + + list_for_each_entry(vcmd, &vdev->cmd_list, entry) { + if (vcmd->status == VHBA_REQ_PENDING) { + break; + } + } + + if (&vcmd->entry == &vdev->cmd_list) { + vcmd = NULL; + } + + return vcmd; +} + +static inline struct vhba_command *match_command (struct vhba_device *vdev, u32 tag) +{ + struct vhba_command *vcmd; + + list_for_each_entry(vcmd, &vdev->cmd_list, entry) { + if (vcmd->cmd->serial_number == tag) { + break; + } + } + + if (&vcmd->entry == &vdev->cmd_list) { + vcmd = NULL; + } + + return vcmd; +} + +static struct vhba_command *wait_command (struct vhba_device *vdev, unsigned long flags) +{ + struct vhba_command *vcmd; + DEFINE_WAIT(wait); + + while (!(vcmd = next_command(vdev))) { + if (signal_pending(current)) { + break; + } + + prepare_to_wait(&vdev->cmd_wq, &wait, TASK_INTERRUPTIBLE); + + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + schedule(); + + spin_lock_irqsave(&vdev->cmd_lock, flags); + } + + finish_wait(&vdev->cmd_wq, &wait); + if (vcmd) { + vcmd->status = VHBA_REQ_READING; + } + + return vcmd; +} + +static ssize_t vhba_ctl_read (struct file *file, char __user *buf, size_t buf_len, loff_t *offset) +{ + struct vhba_device *vdev; + struct vhba_command *vcmd; + ssize_t ret; + unsigned long flags; + + vdev = file->private_data; + + /* Get next command */ + if (file->f_flags & O_NONBLOCK) { + /* Non-blocking variant */ + spin_lock_irqsave(&vdev->cmd_lock, flags); + vcmd = next_command(vdev); + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + if (!vcmd) { + return -EWOULDBLOCK; + } + } else { + /* Blocking variant */ + spin_lock_irqsave(&vdev->cmd_lock, flags); + vcmd = wait_command(vdev, flags); + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + if (!vcmd) { + return -ERESTARTSYS; + } + } + + ret = do_request(vcmd->cmd, buf, buf_len); + + spin_lock_irqsave(&vdev->cmd_lock, flags); + if (ret >= 0) { + vcmd->status = VHBA_REQ_SENT; + *offset += ret; + } else { + vcmd->status = VHBA_REQ_PENDING; + } + + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + return ret; +} + +static ssize_t vhba_ctl_write (struct file *file, const char __user *buf, size_t buf_len, loff_t *offset) +{ + struct vhba_device *vdev; + struct vhba_command *vcmd; + struct vhba_response res; + ssize_t ret; + unsigned long flags; + + if (buf_len < sizeof(res)) { + return -EIO; + } + + if (copy_from_user(&res, buf, sizeof(res))) { + return -EFAULT; + } + + vdev = file->private_data; + + spin_lock_irqsave(&vdev->cmd_lock, flags); + vcmd = match_command(vdev, res.tag); + if (!vcmd || vcmd->status != VHBA_REQ_SENT) { + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + DPRINTK("not expecting response\n"); + return -EIO; + } + vcmd->status = VHBA_REQ_WRITING; + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + ret = do_response(vcmd->cmd, buf + sizeof(res), buf_len - sizeof(res), &res); + + spin_lock_irqsave(&vdev->cmd_lock, flags); + if (ret >= 0) { + vcmd->cmd->scsi_done(vcmd->cmd); + ret += sizeof(res); + + /* don't compete with vhba_device_dequeue */ + if (!list_empty(&vcmd->entry)) { + list_del_init(&vcmd->entry); + vhba_free_command(vcmd); + } + } else { + vcmd->status = VHBA_REQ_SENT; + } + + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + return ret; +} + +static long vhba_ctl_ioctl (struct file *file, unsigned int cmd, unsigned long arg) +{ + struct vhba_device *vdev = file->private_data; + struct vhba_host *vhost; + struct scsi_device *sdev; + + switch (cmd) { + case 0xBEEF001: { + vhost = platform_get_drvdata(&vhba_platform_device); + sdev = scsi_device_lookup(vhost->shost, 0, vdev->id, 0); + + if (sdev) { + int id[4] = { + sdev->host->host_no, + sdev->channel, + sdev->id, + sdev->lun + }; + + scsi_device_put(sdev); + + if (copy_to_user((void *)arg, id, sizeof(id))) { + return -EFAULT; + } + + return 0; + } else { + return -ENODEV; + } + } + } + + return -ENOTTY; +} + +#ifdef CONFIG_COMPAT +static long vhba_ctl_compat_ioctl (struct file *file, unsigned int cmd, unsigned long arg) +{ + unsigned long compat_arg = (unsigned long)compat_ptr(arg); + return vhba_ctl_ioctl(file, cmd, compat_arg); +} +#endif + +static unsigned int vhba_ctl_poll (struct file *file, poll_table *wait) +{ + struct vhba_device *vdev = file->private_data; + unsigned int mask = 0; + unsigned long flags; + + poll_wait(file, &vdev->cmd_wq, wait); + + spin_lock_irqsave(&vdev->cmd_lock, flags); + if (next_command(vdev)) { + mask |= POLLIN | POLLRDNORM; + } + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + return mask; +} + +static int vhba_ctl_open (struct inode *inode, struct file *file) +{ + struct vhba_device *vdev; + int retval; + + DPRINTK("open\n"); + + /* check if vhba is probed */ + if (!platform_get_drvdata(&vhba_platform_device)) { + return -ENODEV; + } + + vdev = vhba_device_alloc(); + if (!vdev) { + return -ENOMEM; + } + + if (!(retval = vhba_add_device(vdev))) { + file->private_data = vdev; + } + + vhba_device_put(vdev); + + return retval; +} + +static int vhba_ctl_release (struct inode *inode, struct file *file) +{ + struct vhba_device *vdev; + struct vhba_command *vcmd; + unsigned long flags; + + DPRINTK("release\n"); + + vdev = file->private_data; + + vhba_device_get(vdev); + vhba_remove_device(vdev); + + spin_lock_irqsave(&vdev->cmd_lock, flags); + list_for_each_entry(vcmd, &vdev->cmd_list, entry) { + WARN_ON(vcmd->status == VHBA_REQ_READING || vcmd->status == VHBA_REQ_WRITING); + + scmd_warn(vcmd->cmd, "device released with command %lu\n", vcmd->cmd->serial_number); + vcmd->cmd->result = DID_NO_CONNECT << 16; + vcmd->cmd->scsi_done(vcmd->cmd); + + vhba_free_command(vcmd); + } + INIT_LIST_HEAD(&vdev->cmd_list); + spin_unlock_irqrestore(&vdev->cmd_lock, flags); + + vhba_device_put(vdev); + + return 0; +} + +static struct file_operations vhba_ctl_fops = { + .owner = THIS_MODULE, + .open = vhba_ctl_open, + .release = vhba_ctl_release, + .read = vhba_ctl_read, + .write = vhba_ctl_write, + .poll = vhba_ctl_poll, + .unlocked_ioctl = vhba_ctl_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = vhba_ctl_compat_ioctl, +#endif +}; + +static struct miscdevice vhba_miscdev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "vhba_ctl", + .fops = &vhba_ctl_fops, +}; + +static int vhba_probe (struct platform_device *pdev) +{ + struct Scsi_Host *shost; + struct vhba_host *vhost; + int i; + + shost = scsi_host_alloc(&vhba_template, sizeof(struct vhba_host)); + if (!shost) { + return -ENOMEM; + } + + shost->max_id = VHBA_MAX_ID; + /* we don't support lun > 0 */ + shost->max_lun = 1; + shost->max_cmd_len = MAX_COMMAND_SIZE; + + vhost = (struct vhba_host *)shost->hostdata; + memset(vhost, 0, sizeof(*vhost)); + + vhost->shost = shost; + vhost->num_devices = 0; + spin_lock_init(&vhost->dev_lock); + spin_lock_init(&vhost->cmd_lock); + INIT_WORK(&vhost->scan_devices, vhba_scan_devices); + vhost->cmd_next = 0; + for (i = 0; i < vhost->shost->can_queue; i++) { + vhost->commands[i].status = VHBA_REQ_FREE; + } + + platform_set_drvdata(pdev, vhost); + + if (scsi_add_host(shost, &pdev->dev)) { + scsi_host_put(shost); + return -ENOMEM; + } + + return 0; +} + +static int vhba_remove (struct platform_device *pdev) +{ + struct vhba_host *vhost; + struct Scsi_Host *shost; + + vhost = platform_get_drvdata(pdev); + shost = vhost->shost; + + scsi_remove_host(shost); + scsi_host_put(shost); + + return 0; +} + +static void vhba_release (struct device * dev) +{ + return; +} + +static struct platform_device vhba_platform_device = { + .name = "vhba", + .id = -1, + .dev = { + .release = vhba_release, + }, +}; + +static struct platform_driver vhba_platform_driver = { + .driver = { + .owner = THIS_MODULE, + .name = "vhba", + }, + .probe = vhba_probe, + .remove = vhba_remove, +}; + +static int __init vhba_init (void) +{ + int ret; + + ret = platform_device_register(&vhba_platform_device); + if (ret < 0) { + return ret; + } + + ret = platform_driver_register(&vhba_platform_driver); + if (ret < 0) { + platform_device_unregister(&vhba_platform_device); + return ret; + } + + ret = misc_register(&vhba_miscdev); + if (ret < 0) { + platform_driver_unregister(&vhba_platform_driver); + platform_device_unregister(&vhba_platform_device); + return ret; + } + + return 0; +} + +static void __exit vhba_exit(void) +{ + misc_deregister(&vhba_miscdev); + platform_driver_unregister(&vhba_platform_driver); + platform_device_unregister(&vhba_platform_device); +} + +module_init(vhba_init); +module_exit(vhba_exit); + diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 9510305..c5af5f0 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -75,6 +75,19 @@ config VT_CONSOLE_SLEEP def_bool y depends on VT_CONSOLE && PM_SLEEP +config NR_TTY_DEVICES + int "Maximum tty device number" + depends on VT + range 12 63 + default 63 + ---help--- + This option is used to change the number of tty devices in /dev. + The default value is 63. The lowest number you can set is 12, + 63 is also the upper limit so we don't overrun the serial + consoles. + + If unsure, say 63. + config HW_CONSOLE bool depends on VT && !UML diff --git a/drivers/video/logo/Kconfig b/drivers/video/logo/Kconfig index 0037104..2dae131 100644 --- a/drivers/video/logo/Kconfig +++ b/drivers/video/logo/Kconfig @@ -15,71 +15,138 @@ config FB_LOGO_EXTRA depends on FB=y default y if SPU_BASE +config LOGO_RANDOM + bool "Select random available logo" + default y + help + Enable this option to use any available logo randomly at bootup. + +comment "Available logos" + +config LOGO_PCK_CLUT224 + bool "224-color Zen Kernel/Meditating Tux logo" + default y + config LOGO_LINUX_MONO bool "Standard black and white Linux logo" - default y + default n config LOGO_LINUX_VGA16 bool "Standard 16-color Linux logo" - default y + default n config LOGO_LINUX_CLUT224 bool "Standard 224-color Linux logo" - default y + default n config LOGO_BLACKFIN_VGA16 bool "16-colour Blackfin Processor Linux logo" depends on BLACKFIN - default y + default n config LOGO_BLACKFIN_CLUT224 bool "224-colour Blackfin Processor Linux logo" depends on BLACKFIN - default y + default n + +config LOGO_OLDPCK_CLUT224 + bool "224-color Old Zen Kernel logo" + depends on LOGO + default n + +config LOGO_ARCH_CLUT224 + bool "224-color Arch Linux logo" + depends on LOGO + default n + +config LOGO_GENTOO_CLUT224 + bool "224-color Gentoo Linux logo" + depends on LOGO + default n + +config LOGO_EXHERBO_CLUT224 + bool "224-color Exherbo Linux logo" + depends on LOGO + default n + +config LOGO_SLACKWARE_CLUT224 + bool "224-color Slackware Linux logo" + depends on LOGO + default n + +config LOGO_DEBIAN_CLUT224 + bool "224-color Debian Linux logo" + depends on LOGO + default n + +config LOGO_FEDORASIMPLE_CLUT224 + bool "224-color Fedora Simple Linux logo" + depends on LOGO + default n + +config LOGO_FEDORAGLOSSY_CLUT224 + bool "224-color Fedora Glossy Linux logo" + depends on LOGO + default n + +config LOGO_TITS_CLUT224 + bool "224-color Tits logo" + depends on LOGO + default n + +config LOGO_BSD_CLUT224 + bool "224-color BSD Devil logo" + depends on LOGO + default n + +config LOGO_FBSD_CLUT224 + bool "224-color FreeBSD logo" + depends on LOGO + default n config LOGO_DEC_CLUT224 bool "224-color Digital Equipment Corporation Linux logo" depends on MACH_DECSTATION || ALPHA - default y + default n config LOGO_MAC_CLUT224 bool "224-color Macintosh Linux logo" depends on MAC - default y + default n config LOGO_PARISC_CLUT224 bool "224-color PA-RISC Linux logo" depends on PARISC - default y + default n config LOGO_SGI_CLUT224 bool "224-color SGI Linux logo" depends on SGI_IP22 || SGI_IP27 || SGI_IP32 - default y + default n config LOGO_SUN_CLUT224 bool "224-color Sun Linux logo" depends on SPARC - default y + default n config LOGO_SUPERH_MONO bool "Black and white SuperH Linux logo" depends on SUPERH - default y + default n config LOGO_SUPERH_VGA16 bool "16-color SuperH Linux logo" depends on SUPERH - default y + default n config LOGO_SUPERH_CLUT224 bool "224-color SuperH Linux logo" depends on SUPERH - default y + default n config LOGO_M32R_CLUT224 bool "224-color M32R Linux logo" depends on M32R - default y + default n endif # LOGO diff --git a/drivers/video/logo/Makefile b/drivers/video/logo/Makefile index 3b43781..6a34664 100644 --- a/drivers/video/logo/Makefile +++ b/drivers/video/logo/Makefile @@ -6,6 +6,18 @@ obj-$(CONFIG_LOGO_LINUX_VGA16) += logo_linux_vga16.o obj-$(CONFIG_LOGO_LINUX_CLUT224) += logo_linux_clut224.o obj-$(CONFIG_LOGO_BLACKFIN_CLUT224) += logo_blackfin_clut224.o obj-$(CONFIG_LOGO_BLACKFIN_VGA16) += logo_blackfin_vga16.o +obj-$(CONFIG_LOGO_PCK_CLUT224) += logo_zen_clut224.o +obj-$(CONFIG_LOGO_OLDPCK_CLUT224) += logo_oldzen_clut224.o +obj-$(CONFIG_LOGO_ARCH_CLUT224) += logo_arch_clut224.o +obj-$(CONFIG_LOGO_GENTOO_CLUT224) += logo_gentoo_clut224.o +obj-$(CONFIG_LOGO_EXHERBO_CLUT224) += logo_exherbo_clut224.o +obj-$(CONFIG_LOGO_SLACKWARE_CLUT224) += logo_slackware_clut224.o +obj-$(CONFIG_LOGO_DEBIAN_CLUT224) += logo_debian_clut224.o +obj-$(CONFIG_LOGO_FEDORASIMPLE_CLUT224) += logo_fedorasimple_clut224.o +obj-$(CONFIG_LOGO_FEDORAGLOSSY_CLUT224) += logo_fedoraglossy_clut224.o +obj-$(CONFIG_LOGO_TITS_CLUT224) += logo_tits_clut224.o +obj-$(CONFIG_LOGO_BSD_CLUT224) += logo_bsd_clut224.o +obj-$(CONFIG_LOGO_FBSD_CLUT224) += logo_fbsd_clut224.o obj-$(CONFIG_LOGO_DEC_CLUT224) += logo_dec_clut224.o obj-$(CONFIG_LOGO_MAC_CLUT224) += logo_mac_clut224.o obj-$(CONFIG_LOGO_PARISC_CLUT224) += logo_parisc_clut224.o diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c index 4d50bfd..7f5a6fe 100644 --- a/drivers/video/logo/logo.c +++ b/drivers/video/logo/logo.c @@ -1,26 +1,127 @@ /* - * Linux logo to be displayed on boot - * - * Copyright (C) 1996 Larry Ewing (lewing@isc.tamu.edu) - * Copyright (C) 1996,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) - * Copyright (C) 2001 Greg Banks - * Copyright (C) 2001 Jan-Benedict Glaw - * Copyright (C) 2003 Geert Uytterhoeven - */ +* Linux logo to be displayed on boot +* +* Copyright (C) 1996 Larry Ewing (lewing@isc.tamu.edu) +* Copyright (C) 1996,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) +* Copyright (C) 2001 Greg Banks +* Copyright (C) 2001 Jan-Benedict Glaw +* Copyright (C) 2003 Geert Uytterhoeven +*/ #include #include #include +#ifdef CONFIG_LOGO_RANDOM +#include +#endif + #ifdef CONFIG_M68K #include #endif + static bool nologo; module_param(nologo, bool, 0); MODULE_PARM_DESC(nologo, "Disables startup logo"); +/* Monochromatic logos */ +static const struct linux_logo *logo_mono[] = { +#ifdef CONFIG_LOGO_LINUX_MONO + &logo_linux_mono, /* Generic Linux logo */ +#endif +#ifdef CONFIG_LOGO_SUPERH_MONO + &logo_superh_mono, /* SuperH Linux logo */ +#endif +}; + +/* 16-colour logos */ +static const struct linux_logo *logo_vga16[] = { +#ifdef CONFIG_LOGO_LINUX_VGA16 + &logo_linux_vga16, /* Generic Linux logo */ +#endif +#ifdef CONFIG_LOGO_BLACKFIN_VGA16 + &logo_blackfin_vga16, /* Blackfin processor logo */ +#endif +#ifdef CONFIG_LOGO_SUPERH_VGA16 + &logo_superh_vga16, /* SuperH Linux logo */ +#endif +}; + +/* 224-colour logos */ +static const struct linux_logo *logo_clut224[] = { +#ifdef CONFIG_LOGO_LINUX_CLUT224 + &logo_linux_clut224, /* Generic Linux logo */ +#endif +#ifdef CONFIG_LOGO_BLACKFIN_CLUT224 + &logo_blackfin_clut224, /* Blackfin Linux logo */ +#endif +#ifdef CONFIG_LOGO_DEC_CLUT224 + &logo_dec_clut224, /* DEC Linux logo on MIPS/MIPS64 or ALPHA */ +#endif +#ifdef CONFIG_LOGO_MAC_CLUT224 + &logo_mac_clut224, /* Macintosh Linux logo on m68k */ +#endif +#ifdef CONFIG_LOGO_PARISC_CLUT224 + &logo_parisc_clut224, /* PA-RISC Linux logo */ +#endif +#ifdef CONFIG_LOGO_SGI_CLUT224 + &logo_sgi_clut224, /* SGI Linux logo on MIPS/MIPS64 */ +#endif +#ifdef CONFIG_LOGO_SUN_CLUT224 + &logo_sun_clut224, /* Sun Linux logo */ +#endif +#ifdef CONFIG_LOGO_SUPERH_CLUT224 + &logo_superh_clut224, /* SuperH Linux logo */ +#endif +#ifdef CONFIG_LOGO_M32R_CLUT224 + &logo_m32r_clut224, /* M32R Linux logo */ +#endif +#ifdef CONFIG_LOGO_PCK_CLUT224 + &logo_zen_clut224, /* Zen-Kernel logo */ +#endif +#ifdef CONFIG_LOGO_OLDPCK_CLUT224 + &logo_oldzen_clut224, /* Old Zen-Kernel logo */ +#endif +#ifdef CONFIG_LOGO_ARCH_CLUT224 + &logo_arch_clut224, /* Arch Linux logo */ +#endif +#ifdef CONFIG_LOGO_GENTOO_CLUT224 + &logo_gentoo_clut224, /* Gentoo Linux logo */ +#endif +#ifdef CONFIG_LOGO_EXHERBO_CLUT224 + &logo_exherbo_clut224, /* Exherbo Linux logo */ +#endif +#ifdef CONFIG_LOGO_SLACKWARE_CLUT224 + &logo_slackware_clut224, /* Slackware Linux logo */ +#endif +#ifdef CONFIG_LOGO_DEBIAN_CLUT224 + &logo_debian_clut224, /* Debian Linux logo */ +#endif +#ifdef CONFIG_LOGO_FEDORASIMPLE_CLUT224 + &logo_fedorasimple_clut224, /* Fedora Simple logo */ +#endif +#ifdef CONFIG_LOGO_FEDORAGLOSSY_CLUT224 + &logo_fedoraglossy_clut224, /* Fedora Glossy logo */ +#endif +#ifdef CONFIG_LOGO_TITS_CLUT224 + &logo_tits_clut224, /* Tits logo */ +#endif +#ifdef CONFIG_LOGO_BSD_CLUT224 + &logo_bsd_clut224, /* BSD logo */ +#endif +#ifdef CONFIG_LOGO_FBSD_CLUT224 + &logo_fbsd_clut224, /* Free BSD logo */ +#endif +}; + +#ifdef CONFIG_LOGO_RANDOM +#define LOGO_INDEX(s) (get_random_int() % s) +#else +#define LOGO_INDEX(s) (s - 1) +#endif + /* * Logos are located in the initdata, and will be freed in kernel_init. * Use late_init to mark the logos as freed to prevent any further use. @@ -43,75 +144,30 @@ late_initcall_sync(fb_logo_late_init); const struct linux_logo * __ref fb_find_logo(int depth) { const struct linux_logo *logo = NULL; + const struct linux_logo **array = NULL; + unsigned int size; if (nologo || logos_freed) return NULL; + /* Select logo array */ if (depth >= 1) { -#ifdef CONFIG_LOGO_LINUX_MONO - /* Generic Linux logo */ - logo = &logo_linux_mono; -#endif -#ifdef CONFIG_LOGO_SUPERH_MONO - /* SuperH Linux logo */ - logo = &logo_superh_mono; -#endif + array = logo_mono; + size = ARRAY_SIZE(logo_mono); } - if (depth >= 4) { -#ifdef CONFIG_LOGO_LINUX_VGA16 - /* Generic Linux logo */ - logo = &logo_linux_vga16; -#endif -#ifdef CONFIG_LOGO_BLACKFIN_VGA16 - /* Blackfin processor logo */ - logo = &logo_blackfin_vga16; -#endif -#ifdef CONFIG_LOGO_SUPERH_VGA16 - /* SuperH Linux logo */ - logo = &logo_superh_vga16; -#endif + array = logo_vga16; + size = ARRAY_SIZE(logo_vga16); } - if (depth >= 8) { -#ifdef CONFIG_LOGO_LINUX_CLUT224 - /* Generic Linux logo */ - logo = &logo_linux_clut224; -#endif -#ifdef CONFIG_LOGO_BLACKFIN_CLUT224 - /* Blackfin Linux logo */ - logo = &logo_blackfin_clut224; -#endif -#ifdef CONFIG_LOGO_DEC_CLUT224 - /* DEC Linux logo on MIPS/MIPS64 or ALPHA */ - logo = &logo_dec_clut224; -#endif -#ifdef CONFIG_LOGO_MAC_CLUT224 - /* Macintosh Linux logo on m68k */ - if (MACH_IS_MAC) - logo = &logo_mac_clut224; -#endif -#ifdef CONFIG_LOGO_PARISC_CLUT224 - /* PA-RISC Linux logo */ - logo = &logo_parisc_clut224; -#endif -#ifdef CONFIG_LOGO_SGI_CLUT224 - /* SGI Linux logo on MIPS/MIPS64 */ - logo = &logo_sgi_clut224; -#endif -#ifdef CONFIG_LOGO_SUN_CLUT224 - /* Sun Linux logo */ - logo = &logo_sun_clut224; -#endif -#ifdef CONFIG_LOGO_SUPERH_CLUT224 - /* SuperH Linux logo */ - logo = &logo_superh_clut224; -#endif -#ifdef CONFIG_LOGO_M32R_CLUT224 - /* M32R Linux logo */ - logo = &logo_m32r_clut224; -#endif + array = logo_clut224; + size = ARRAY_SIZE(logo_clut224); } + + /* We've got some logos to display */ + if (array && size) + logo = array[LOGO_INDEX(size)]; + return logo; } EXPORT_SYMBOL_GPL(fb_find_logo); diff --git b/drivers/video/logo/logo_arch_clut224.ppm b/drivers/video/logo/logo_arch_clut224.ppm new file mode 100644 index 0000000..e4d8daa --- /dev/null +++ b/drivers/video/logo/logo_arch_clut224.ppm @@ -0,0 +1,43204 @@ +P3 +# CREATOR: GIMP PNM Filter Version 1.1 +120 120 +255 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 +0 +2 +0 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