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* docs: fix broken doc references due to renamesMauro Carvalho Chehab2019-07-171-2/+2
| | | | | | | Some files got renamed but probably due to some merge conflicts, a few references still point to the old locations. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
* docs: locking: add it to the main indexMauro Carvalho Chehab2019-07-151-1/+1
| | | | | | | The locking directory is part of the Kernel API bookset. Add it to the index file. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
* docs: locking: convert docs to ReST and rename to *.rstMauro Carvalho Chehab2019-07-1510-376/+500
| | | | | | | | | | | | | | | | | | | | | | Convert the locking documents to ReST and add them to the kernel development book where it belongs. Most of the stuff here is just to make Sphinx to properly parse the text file, as they're already in good shape, not requiring massive changes in order to be parsed. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>
* locking/lockdep: Add explanation to lock usage rules in lockdep design docYuyang Du2019-06-031-10/+23
| | | | | | | | | | | | | | | | | The irq usage and lock dependency rules that if violated a deacklock may happen are explained in more detail. Signed-off-by: Yuyang Du <duyuyang@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bvanassche@acm.org Cc: frederic@kernel.org Cc: ming.lei@redhat.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190506081939.74287-17-duyuyang@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Add description and explanation in lockdep design docYuyang Du2019-06-031-18/+61
| | | | | | | | | | | | | | | | | | More words are added to lockdep design document regarding key concepts, which should help people without lockdep experience read and understand lockdep reports. Signed-off-by: Yuyang Du <duyuyang@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bvanassche@acm.org Cc: frederic@kernel.org Cc: ming.lei@redhat.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190506081939.74287-3-duyuyang@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/locking/lockdep: Drop last two chars of sample statesGeert Uytterhoeven2019-03-041-2/+2
| | | | | | | | | | | Since the removal of FS_RECLAIM annotations, lockdep states contain four characters, not six. Fixes: e5684bbfc3f03480 ("Documentation/locking/lockdep: Update info about states") Fixes: d92a8cfcb37ecd13 ("locking/lockdep: Rework FS_RECLAIM annotation") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* Merge tag 'docs-4.20' of git://git.lwn.net/linuxLinus Torvalds2018-10-241-16/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull documentation updates from Jonathan Corbet: "This is a fairly typical cycle for documentation. There's some welcome readability improvements for the formatted output, some LICENSES updates including the addition of the ISC license, the removal of the unloved and unmaintained 00-INDEX files, the deprecated APIs document from Kees, more MM docs from Mike Rapoport, and the usual pile of typo fixes and corrections" * tag 'docs-4.20' of git://git.lwn.net/linux: (41 commits) docs: Fix typos in histogram.rst docs: Introduce deprecated APIs list kernel-doc: fix declaration type determination doc: fix a typo in adding-syscalls.rst docs/admin-guide: memory-hotplug: remove table of contents doc: printk-formats: Remove bogus kobject references for device nodes Documentation: preempt-locking: Use better example dm flakey: Document "error_writes" feature docs/completion.txt: Fix a couple of punctuation nits LICENSES: Add ISC license text LICENSES: Add note to CDDL-1.0 license that it should not be used docs/core-api: memory-hotplug: add some details about locking internals docs/core-api: rename memory-hotplug-notifier to memory-hotplug docs: improve readability for people with poorer eyesight yama: clarify ptrace_scope=2 in Yama documentation docs/vm: split memory hotplug notifier description to Documentation/core-api docs: move memory hotplug description into admin-guide/mm doc: Fix acronym "FEKEK" in ecryptfs docs: fix some broken documentation references iommu: Fix passthrough option documentation ...
| * Drop all 00-INDEX files from Documentation/Henrik Austad2018-09-091-16/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a respin with a wider audience (all that get_maintainer returned) and I know this spams a *lot* of people. Not sure what would be the correct way, so my apologies for ruining your inbox. The 00-INDEX files are supposed to give a summary of all files present in a directory, but these files are horribly out of date and their usefulness is brought into question. Often a simple "ls" would reveal the same information as the filenames are generally quite descriptive as a short introduction to what the file covers (it should not surprise anyone what Documentation/sched/sched-design-CFS.txt covers) A few years back it was mentioned that these files were no longer really needed, and they have since then grown further out of date, so perhaps it is time to just throw them out. A short status yields the following _outdated_ 00-INDEX files, first counter is files listed in 00-INDEX but missing in the directory, last is files present but not listed in 00-INDEX. List of outdated 00-INDEX: Documentation: (4/10) Documentation/sysctl: (0/1) Documentation/timers: (1/0) Documentation/blockdev: (3/1) Documentation/w1/slaves: (0/1) Documentation/locking: (0/1) Documentation/devicetree: (0/5) Documentation/power: (1/1) Documentation/powerpc: (0/5) Documentation/arm: (1/0) Documentation/x86: (0/9) Documentation/x86/x86_64: (1/1) Documentation/scsi: (4/4) Documentation/filesystems: (2/9) Documentation/filesystems/nfs: (0/2) Documentation/cgroup-v1: (0/2) Documentation/kbuild: (0/4) Documentation/spi: (1/0) Documentation/virtual/kvm: (1/0) Documentation/scheduler: (0/2) Documentation/fb: (0/1) Documentation/block: (0/1) Documentation/networking: (6/37) Documentation/vm: (1/3) Then there are 364 subdirectories in Documentation/ with several files that are missing 00-INDEX alltogether (and another 120 with a single file and no 00-INDEX). I don't really have an opinion to whether or not we /should/ have 00-INDEX, but the above 00-INDEX should either be removed or be kept up to date. If we should keep the files, I can try to keep them updated, but I rather not if we just want to delete them anyway. As a starting point, remove all index-files and references to 00-INDEX and see where the discussion is going. Signed-off-by: Henrik Austad <henrik@austad.us> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Just-do-it-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: [Almost everybody else] Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | Documentation/lockstat: Fix trivial typoAndrew Murray2018-10-021-1/+1
|/ | | | | | | | | | | | | | | Fix incorrect line number in example output Signed-off-by: Andrew Murray <andrew.murray@arm.com> Cc: Jiri Kosina <trivial@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1538391663-54524-1-git-send-email-andrew.murray@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking: Implement an algorithm choice for Wound-Wait mutexesThomas Hellstrom2018-07-031-11/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current Wound-Wait mutex algorithm is actually not Wound-Wait but Wait-Die. Implement also Wound-Wait as a per-ww-class choice. Wound-Wait is, contrary to Wait-Die a preemptive algorithm and is known to generate fewer backoffs. Testing reveals that this is true if the number of simultaneous contending transactions is small. As the number of simultaneous contending threads increases, Wait-Wound becomes inferior to Wait-Die in terms of elapsed time. Possibly due to the larger number of held locks of sleeping transactions. Update documentation and callers. Timings using git://people.freedesktop.org/~thomash/ww_mutex_test tag patch-18-06-15 Each thread runs 100000 batches of lock / unlock 800 ww mutexes randomly chosen out of 100000. Four core Intel x86_64: Algorithm #threads Rollbacks time Wound-Wait 4 ~100 ~17s. Wait-Die 4 ~150000 ~19s. Wound-Wait 16 ~360000 ~109s. Wait-Die 16 ~450000 ~82s. Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Sean Paul <seanpaul@chromium.org> Cc: David Airlie <airlied@linux.ie> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-doc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Co-authored-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@kernel.org>
* locking: WW mutex cleanupPeter Ziljstra2018-07-031-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | Make the WW mutex code more readable by adding comments, splitting up functions and pointing out that we're actually using the Wait-Die algorithm. Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Sean Paul <seanpaul@chromium.org> Cc: David Airlie <airlied@linux.ie> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-doc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Co-authored-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Acked-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'v4.16-rc2' into locking/core, to refresh the branchIngo Molnar2018-02-211-32/+17
|\ | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Documentation/locking/mutex-design: Update to reflect latest changesJuri Lelli2018-02-111-32/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 3ca0ff571b09 ("locking/mutex: Rework mutex::owner") reworked the basic mutex implementation to deal with several problems. Documentation was however left unchanged and became stale. Update mutex-design.txt to reflect changes introduced by the above commit. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20180209160114.19980-1-juri.lelli@redhat.com [ Small readability tweaks to the text. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Documentation/locking/lockdep: Add section about available annotationsJuri Lelli2018-02-141-0/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add section about annotations that can be used to perform additional runtime checking of locking correctness: assert that certain locks are held and prevent accidental unlocking. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20180213185519.18186-3-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Documentation/locking/lockdep: Update info about statesJuri Lelli2018-02-141-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | Commit: d92a8cfcb37e ("locking/lockdep: Rework FS_RECLAIM annotation") removed the 'reclaim_fs' lockdep STATE. Reflect the change in the documentation. While we are at it, also clarify the formula to calculate the number of state bits. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20180213185519.18186-2-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'for-mingo' of ↵Ingo Molnar2018-01-031-5/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Updates to use cond_resched() instead of cond_resched_rcu_qs() where feasible (currently everywhere except in kernel/rcu and in kernel/torture.c). Also a couple of fixes to avoid sending IPIs to offline CPUs. - Updates to simplify RCU's dyntick-idle handling. - Updates to remove almost all uses of smp_read_barrier_depends() and read_barrier_depends(). - Miscellaneous fixes. - Torture-test updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * torture: Eliminate torture_runnable and perf_runnablePaul E. McKenney2017-12-111-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The purpose of torture_runnable is to allow rcutorture and locktorture to be started and stopped via sysfs when they are built into the kernel (as in not compiled as loadable modules). However, the 0444 permissions for both instances of torture_runnable prevent this use case from ever being put into practice. Given that there have been no complaints about this deficiency, it is reasonable to conclude that no one actually makes use of this sysfs capability. The perf_runnable module parameter for rcuperf is in the same situation. This commit therefore removes both torture_runnable instances as well as perf_runnable. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | locking/lockdep: Remove the cross-release locking checksIngo Molnar2017-12-121-874/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This code (CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y), while it found a number of old bugs initially, was also causing too many false positives that caused people to disable lockdep - which is arguably a worse overall outcome. If we disable cross-release by default but keep the code upstream then in practice the most likely outcome is that we'll allow the situation to degrade gradually, by allowing entropy to introduce more and more false positives, until it overwhelms maintenance capacity. Another bad side effect was that people were trying to work around the false positives by uglifying/complicating unrelated code. There's a marked difference between annotating locking operations and uglifying good code just due to bad lock debugging code ... This gradual decrease in quality happened to a number of debugging facilities in the kernel, and lockdep is pretty complex already, so we cannot risk this outcome. Either cross-release checking can be done right with no false positives, or it should not be included in the upstream kernel. ( Note that it might make sense to maintain it out of tree and go through the false positives every now and then and see whether new bugs were introduced. ) Cc: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation: fix locking rt-mutex doc refsTom Saeger2017-10-191-1/+1
| | | | | Signed-off-by: Tom Saeger <tom.saeger@oracle.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* Merge branch 'linus' into locking/core, to fix up conflictsIngo Molnar2017-09-042-359/+131
|\ | | | | | | | | | | | | Conflicts: mm/page_alloc.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * rtmutex: update rt-mutexAlex Shi2017-08-241-32/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rtmutex remove a pending owner bit in in rt_mutex::owner, in commit 8161239a8bcc ("rtmutex: Simplify PI algorithm and make highest prio task get lock") But the document was changed accordingly. Updating it to a meaningful state. BTW, as 'Steven Rostedt' mentioned: There is still technically a "Pending Owner", it's just not called that anymore. The pending owner happens to be the top_waiter of a lock that has no owner and has been woken up to grab the lock. Signed-off-by: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> To: linux-doc@vger.kernel.org To: linux-kernel@vger.kernel.org To: Jonathan Corbet <corbet@lwn.net> To: Ingo Molnar <mingo@redhat.com> To: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * rtmutex: update rt-mutex-designAlex Shi2017-08-241-327/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rt-mutex-design documents didn't gotten meaningful update from its first version. Even after owner's pending bit was removed in commit 8161239a8bcc ("rtmutex: Simplify PI algorithm and make highest prio task get lock") and priority list 'plist' changed to rbtree. And Peter Zijlstra did some clean up and fix for deadline task changes on tip tree. So update it to latest code and make it meaningful. Steven Rostedt and Sebastian Siewior gave much of comments and input in this doc. Thanks! Signed-off-by: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> To: linux-doc@vger.kernel.org To: linux-kernel@vger.kernel.org To: Jonathan Corbet <corbet@lwn.net> To: Ingo Molnar <mingo@redhat.com> To: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | locking/lockdep: Add 'crossrelease' feature documentationByungchul Park2017-08-101-0/+874
|/ | | | | | | | | | | | | | | | | | | This document describes the concept of crossrelease feature. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-15-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/ww_mutex/Documentation: Update the design documentNicolai Hähnle2017-01-141-4/+8
| | | | | | | | | | | | | | | | | | Document the invariants we maintain for the wait list of ww_mutexes. Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-13-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lglock: Remove lglock implementationPeter Zijlstra2016-09-221-166/+0
| | | | | | | | | | | | It is now unused, remove it before someone else thinks its a good idea to use this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/Documentation/lockdep: Fix spelling mistakesEric Engestrom2016-04-281-2/+2
| | | | | | | | | | | Signed-off-by: Eric Engestrom <eric@engestrom.ch> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1461566229-4717-2-git-send-email-eric@engestrom.ch Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'locking-core-for-linus' of ↵Linus Torvalds2015-11-031-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking changes from Ingo Molnar: "The main changes in this cycle were: - More gradual enhancements to atomic ops: new atomic*_read_ctrl() ops, synchronize atomic_{read,set}() ordering requirements between architectures, add atomic_long_t bitops. (Peter Zijlstra) - Add _{relaxed|acquire|release}() variants for inc/dec atomics and use them in various locking primitives: mutex, rtmutex, mcs, rwsem. This enables weakly ordered architectures (such as arm64) to make use of more locking related optimizations. (Davidlohr Bueso) - Implement atomic[64]_{inc,dec}_relaxed() on ARM. (Will Deacon) - Futex kernel data cache footprint micro-optimization. (Rasmus Villemoes) - pvqspinlock runtime overhead micro-optimization. (Waiman Long) - misc smaller fixlets" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ARM, locking/atomics: Implement _relaxed variants of atomic[64]_{inc,dec} locking/rwsem: Use acquire/release semantics locking/mcs: Use acquire/release semantics locking/rtmutex: Use acquire/release semantics locking/mutex: Use acquire/release semantics locking/asm-generic: Add _{relaxed|acquire|release}() variants for inc/dec atomics atomic: Implement atomic_read_ctrl() atomic, arch: Audit atomic_{read,set}() atomic: Add atomic_long_t bitops futex: Force hot variables into a single cache line locking/pvqspinlock: Kick the PV CPU unconditionally when _Q_SLOW_VAL locking/osq: Relax atomic semantics locking/qrwlock: Rename ->lock to ->wait_lock locking/Documentation/lockstat: Fix typo - lokcing -> locking locking/atomics, cmpxchg: Privatize the inclusion of asm/cmpxchg.h
| * locking/Documentation/lockstat: Fix typo - lokcing -> lockingStephen Boyd2015-09-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jiri Kosina <trivial@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1441842398-25063-1-git-send-email-sboyd@codeaurora.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | locktorture: Support rtmutex torturingDavidlohr Bueso2015-10-061-0/+3
|/ | | | | | | | | | | | | | | | | | | | | Real time mutexes is one of the few general primitives that we do not have in locktorture. Address this -- a few considerations: o To spice things up, enable competing thread(s) to become rt, such that we can stress different prio boosting paths in the rtmutex code. Introduce a ->task_boost callback, only used by rtmutex-torturer. Tasks will boost/deboost around every 50k (arbitrarily) lock/unlock operations. o Hold times are similar to what we have for other locks: only occasionally having longer hold times (per ~200k ops). So we roughly do two full rt boost+deboosting ops with short hold times. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6Linus Torvalds2015-02-112-0/+21
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull documentation updates from Jonathan Corbet: "Highlights this time around include: - A thrashing of SubmittingPatches to bring it out of the "send everything to Linus" era of kernel development. - A new document on completions from Nicholas McGuire - Lots of typo fixes, formatting improvements, corrections, build fixes, and more" * tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (35 commits) Documentation: Fix the wrong command `echo -1 > set_ftrace_pid` for cleaning the filter. can-doc: Fixed a wrong filepath in can.txt Documentation: Fix trivial typo in comment. kgdb,docs: Fix typo and minor style issues Documentation: add description for FTRACE probe status doc: brief user documentation for completion Documentation/misc-devices/mei: Fix indentation of embedded code. Documentation/misc-devices/mei: Fix indentation of enumeration. Documentation/misc-devices/mei: Fix spacing around parentheses. Documentation/misc-devices/mei: Fix formatting of headings. Documentation: devicetree: Fix double words in Doumentation/devicetree Documentation: mm: Fix typo in vm.txt lockstat: Add documentation on contention and contenting points Documentation: fix blackfin gptimers-example build errors Fixes column alignment in table of contents entry 1.9 in Documentation/filesystems/proc.txt CodingStyle: enable emacs display of trailing whitespace DocBook: Do not exceed argument list limit gpio: board.txt: Fix the gpio name example Documentation/SubmittingPatches: unify whitespace/tabs for the DCO MAINTAINERS: Add the docs-next git tree to the maintainer entry ...
| * lockstat: Add documentation on contention and contenting pointsDaniel Wagner2015-01-281-0/+5
| | | | | | | | | | | | | | | | Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| * Update of Documentation/00-INDEXHenrik Austad2014-12-291-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Added files - hsi.txt was added by 3a8ab8af (HSI: Add some general description for the HSI subsystem) - lzo.txt was added by d98a0526 (lzo: document part of the encoding) - xillybus.txt was added by 7051924f (xillybus: Move out of staging) - mailbox.txt was added by 15320fbc (add documentation for mailbox framework) Moved files - xommit 214e0aed (Move locking related docs into Documentation/locking/): * lockdep-design.txt * lockstat.txt * mutex-design.txt * rt-mutex-design.txt * rt-mutex.txt * spinlocks.txt * ww-mutex-design.txt - kselftest.txt was moved by 3c415707 (kselftest: Move the docs to the Documentation dir) CC: Davidlohr Bueso <davidlohr@hp.com> CC: Willy Tarreau <w@1wt.eu> CC: Randy Dunlap <rdunlap@infradead.org> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> CC: Sebastian Reichel <sre@kernel.org> CC: Eli Billauer <eli.billauer@gmail.com> CC: Jonathan Corbet <corbet@lwn.net> CC: Jiri Kosina <trivial@kernel.org> CC: linux-doc@vger.kernel.org CC: linux-kernel@vger.kernel.org Cc: Tim Bird <tim.bird@sonymobile.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Henrik Austad <henrik@austad.us> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | locking/Documentation: Update code pathSeongJae Park2015-01-161-1/+1
|/ | | | | | | | | | | | | | | | | lockdep code has been moved from kernel/ to kernel/locking/ by commit 8eddac3f103736163f49255bcb109edadea167f6 ("locking: Move the lockdep code to kernel/locking/"). But, path to lockdep code in document was not updated. This commit updates the path. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1421176921-27688-1-git-send-email-sj38.park@gmail.com Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-doc@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'core-locking-for-linus' of ↵Linus Torvalds2014-12-091-0/+166
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking tree changes from Ingo Molnar: "Two changes: a documentation update and a ticket locks live lock fix" * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ticketlock: Fix spin_unlock_wait() livelock locking/lglocks: Add documentation of current lglocks implementation
| * locking/lglocks: Add documentation of current lglocks implementationNicholas Mc Guire2014-12-081-0/+166
| | | | | | | | | | | | | | | | | | | Local/global locks are currently not documented anywhere other than in an somewhat out-of-date LWN article - this is an attempt to document the current state of lglocks. This patch is against linux-next 3.18.0-rc6 Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Carsten Emde <c.emde@osadl.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20141208083326.GA29895@opentech.at Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'locking-core-for-linus' of ↵Linus Torvalds2014-10-137-0/+1992
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core locking updates from Ingo Molnar: "The main updates in this cycle were: - mutex MCS refactoring finishing touches: improve comments, refactor and clean up code, reduce debug data structure footprint, etc. - qrwlock finishing touches: remove old code, self-test updates. - small rwsem optimization - various smaller fixes/cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Revert qrwlock recusive stuff locking/rwsem: Avoid double checking before try acquiring write lock locking/rwsem: Move EXPORT_SYMBOL() lines to follow function definition locking/rwlock, x86: Delete unused asm/rwlock.h and rwlock.S locking/rwlock, x86: Clean up asm/spinlock*.h to remove old rwlock code locking/semaphore: Resolve some shadow warnings locking/selftest: Support queued rwlock locking/lockdep: Restrict the use of recursive read_lock() with qrwlock locking/spinlocks: Always evaluate the second argument of spin_lock_nested() locking/Documentation: Update locking/mutex-design.txt disadvantages locking/Documentation: Move locking related docs into Documentation/locking/ locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate locking/mutexes: Refactor optimistic spinning code locking/mcs: Remove obsolete comment locking/mutexes: Document quick lock release when unlocking locking/mutexes: Standardize arguments in lock/unlock slowpaths locking: Remove deprecated smp_mb__() barriers
| * locking/Documentation: Update locking/mutex-design.txt disadvantagesDavidlohr Bueso2014-08-131-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fortunately Jason was able to reduce some of the overhead we had introduced in the original rwsem optimistic spinning - an it is now the same size as mutexes. Update the documentation accordingly. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: aswin@hp.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Link: http://lkml.kernel.org/r/1406752916-3341-7-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/Documentation: Move locking related docs into Documentation/locking/Davidlohr Bueso2014-08-137-0/+1992
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Specifically: Documentation/locking/lockdep-design.txt Documentation/locking/lockstat.txt Documentation/locking/mutex-design.txt Documentation/locking/rt-mutex-design.txt Documentation/locking/rt-mutex.txt Documentation/locking/spinlocks.txt Documentation/locking/ww-mutex-design.txt Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: jason.low2@hp.com Cc: aswin@hp.com Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Mason <clm@fb.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Airlie <airlied@linux.ie> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: David S. Miller <davem@davemloft.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jason Low <jason.low2@hp.com> Cc: Josef Bacik <jbacik@fusionio.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lubomir Rintel <lkundrak@v3.sk> Cc: Masanari Iida <standby24x7@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: fengguang.wu@intel.com Link: http://lkml.kernel.org/r/1406752916-3341-6-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locktorture: Support rwlocksDavidlohr Bueso2014-09-301-0/+5
| | | | | | | | | | Add a "rw_lock" torture test to stress kernel rwlocks and their irq variant. Reader critical regions are 5x longer than writers. As such a similar ratio of lock acquisitions is seen in the statistics. In the case of massive contention, both hold the lock for 1/10 of a second. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* locktorture: Support rwsemsDavidlohr Bueso2014-09-161-0/+2
| | | | | | | | | We can easily do so with our new reader lock support. Just an arbitrary design default: readers have higher (5x) critical region latencies than writers: 50 ms and 10 ms, respectively. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* locktorture: Add infrastructure for torturing read locksDavidlohr Bueso2014-09-161-4/+12
| | | | | | | | | | | | | | | | | | | Most of it is based on what we already have for writers. This allows readers to be very independent (and thus configurable), enabling future module parameters to control things such as rw distribution. Furthermore, readers have their own delaying function, allowing us to test different rw critical region latencies, and stress locking internals. Similarly, statistics, for now will only serve for the number of lock acquisitions -- as opposed to writers, readers have no failure detection. In addition, introduce a new nreaders_stress module parameter. The default number of readers will be the same number of writers threads. Writer threads are interleaved with readers. Documentation is updated, respectively. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* locktorture: Support mutexesDavidlohr Bueso2014-09-161-0/+2
| | | | | | | | | | | | | Add a "mutex_lock" torture test. The main difference with the already existing spinlock tests is that the latency of the critical region is much larger. We randomly delay for (arbitrarily) either 500 ms or, otherwise, 25 ms. While this can considerably reduce the amount of writes compared to non blocking locks, if run long enough it can have the same torturous effect. Furthermore it is more representative of mutex hold times and can stress better things like thrashing. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* locktorture: Add documentationDavidlohr Bueso2014-09-161-0/+130
Just like Documentation/RCU/torture.txt, begin a document for the locktorture module. This module is still pretty green, so I have just added some specific sections to the doc (general desc, params, usage, etc.). Further development should update the file. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> [ paulmck: Apply Randy Dunlap review comments. ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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