| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
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 <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Gustavo Padovan <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Sean Paul <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Kate Stewart <[email protected]>
Cc: Philippe Ombredanne <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Co-authored-by: Thomas Hellstrom <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Hellstrom <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
|
|
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
[ Small readability tweaks to the text. ]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
|
|
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 <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
Signed-off-by: Tom Saeger <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
|
|
Conflicts:
mm/page_alloc.c
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sebastian Siewior <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Thomas Gleixner <[email protected]>
To: [email protected]
To: [email protected]
To: Jonathan Corbet <[email protected]>
To: Ingo Molnar <[email protected]>
To: Peter Zijlstra <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
|
|
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 <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sebastian Siewior <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Thomas Gleixner <[email protected]>
To: [email protected]
To: [email protected]
To: Jonathan Corbet <[email protected]>
To: Ingo Molnar <[email protected]>
To: Peter Zijlstra <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
|
|
This document describes the concept of crossrelease feature.
Signed-off-by: Byungchul Park <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
Document the invariants we maintain for the wait list of ww_mutexes.
Signed-off-by: Nicolai Hähnle <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
It is now unused, remove it before someone else thinks its a good idea
to use this.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
Signed-off-by: Eric Engestrom <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Josh Triplett <[email protected]>
|
|
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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
...
|
|
Signed-off-by: Daniel Wagner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Randy Dunlap <[email protected]>
CC: Greg Kroah-Hartman <[email protected]>
CC: Sebastian Reichel <[email protected]>
CC: Eli Billauer <[email protected]>
CC: Jonathan Corbet <[email protected]>
CC: Jiri Kosina <[email protected]>
CC: [email protected]
CC: [email protected]
Cc: Tim Bird <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Henrik Austad <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
|
|
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
|
|
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 <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Carsten Emde <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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 <[email protected]>
[ paulmck: Apply Randy Dunlap review comments. ]
Signed-off-by: Paul E. McKenney <[email protected]>
|
|
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 <[email protected]>
Acked-by: Jason Low <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Randy Dunlap <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
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 <[email protected]>
Acked-by: Randy Dunlap <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Alexei Starovoitov <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Jason Low <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Lubomir Rintel <[email protected]>
Cc: Masanari Iida <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|