mutex subsystem, ANNOUNCE
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- v1 Latest8 patches 24 repliesIn review
Changes since the previous version from the cover letter · 22 lines
- dropped the semaphore-renaming and migration-helper patches. The patches now contain only the pure mutex subsystem, nothing more.
- removed the fastpath dependency on __HAVE_ARCH_CMPXCHG: now every architecture is able to use the generic mutex_lock/mutex_unlock lockless fastpath. The quality of the fastpath is still as good as in the previous version.
- added ARCH_IMPLEMENTS_MUTEX_FASTPATH for architectures that want to hand-code their own fastpath. The mutex_lock_slowpath, mutex_unlock_slowpath and mutex_lock_interruptible_slowpath global functions can be used by such architectures in this case, and they should implement the mutex_lock(), mutex_unlock() and mutex_lock_interruptible() functions themselves. I have tested this mechanism on x86. (but x86 wants to use the generic functions otherwise, so those changes are not included in this patchqueue.)
- fixed the x86_64 register-clobber bug noticed by Zwane Mwaikambo
- XFS namespace collision fixes from Jes Sorensen
- lots of cleanups to "hide" the debugging code, it should now be much less intrusive visually - kernel/mutex.c is now both smaller and easier to read. There's no reduction in debugging functionality.
- cleaned up the debugging code
- unified all the externally visible debugging functions around the mutex_debug_ prefix.
- added the proper atomic ops to every architecture - so in theory mutexes should now work on every architectures. i386, x86_64 and ia64 was tested.
- created mutex-debug.h to hide some of the debugging details. Moved the mm.h and sched.h debug-function declarations into this file.
- documentation updates
- eliminated the ->file, ->line debugging variant - __FUNCTION__ is good enough and resulted in nicer code.
- properly check for held locks in kfree() too, if DEBUG.
- check for held-lock reinitialization via mutex_init(), if DEBUG.
- more micro-optimizations: eliminated an extra spinlock drop/reacquire in the slowpath.
- dropped waiter->woken, profiles showed that it triggered very rarely.
- dropped the timeout/timer bits - nothing is using them right now, we can add them back later.
- new mutex_trylock() optimization on architectures that support cmpxchg.
- marked ->name as const
- fixed typo: CONFIG_DEBUG_MUTEXESS -> CONFIG_DEBUG_MUTEXES
- mb() -> smp_mb() in mutex_is_locked()
- mutex_trylock doesnt need __sched
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/8 | mutex subsystem, XFS namespace collision fixesfs/ fs/ fs/ +8 more | +52 | 1 reply | |
| 2/8 | mutex subsystem, add atomic_cmpxchg() to all archesinclude/ include/ include/ +19 more | +29 | 2 replies | |
| 3/8 | mutex subsystem, add atomic_*_call_if_*() to i386include/ | +55 | 8 replies | |
| 4/8 | mutex subsystem, add atomic_*_call_if_*() to x86_64include/ | +56 | 0 replies | |
| 5/8 | mutex subsystem, add atomic_*_call_if_*() defaults to the remaining archesinclude/ include/ include/ +18 more | +269 | 0 replies | |
| 6/8 | mutex subsystem, coreinclude/ kernel/ kernel/ | +554 | 0 replies | |
| 7/8 | mutex subsystem, debugging codeinclude/ include/ kernel/ +2 more | +545 | 0 replies | |
| 8/8 | mutex subsystem, more debugging codearch/ drivers/ include/ +5 more | +47 | 0 replies |
Reviews trailers per patch
No Reviewed-by, Acked-by or Tested-by trailers for v1 yet.
Cover letter [patch 0/8] mutex subsystem, ANNOUNCE
this is the latest version of the mutex subsystem patch-queue. It consists of the following patches:
xfs-mutex-namespace-collision-fix.patch
add-atomic-xchg.patch
add-atomic-call-func-i386.patch
add-atomic-call-func-x86_64.patch
add-atomic-call-wrappers-rest.patch
mutex-core.patch
mutex-debug.patch
mutex-debug-more.patch
the patches are against Linus' latest tree, and were tested on i386, x86_64 and ia64. [the tests were also done in DEBUG_MUTEX_FULL mode, to make sure the code works fine. MUTEX_FULL support is not included in this patchqueue].
The patches can also be downloaded from:
http://redhat.com/~mingo/generic-mutex-subsystem/
Changes since the previous version:
- dropped the semaphore-renaming and migration-helper patches. The patches now contain only the pure mutex subsystem, nothing more.
- removed the fastpath dependency on __HAVE_ARCH_CMPXCHG: now every architecture is able to use the generic mutex_lock/mutex_unlock lockless fastpath. The quality of the fastpath is still as good as in the previous version.
- added ARCH_IMPLEMENTS_MUTEX_FASTPATH for architectures that want to hand-code their own fastpath. The mutex_lock_slowpath, mutex_unlock_slowpath and mutex_lock_interruptible_slowpath global functions can be used by such architectures in this case, and they should implement the mutex_lock(), mutex_unlock() and mutex_lock_interruptible() functions themselves. I have tested this mechanism on x86. (but x86 wants to use the generic functions otherwise, so those changes are not included in this patchqueue.)
- fixed the x86_64 register-clobber bug noticed by Zwane Mwaikambo
- XFS namespace collision fixes from Jes Sorensen
- lots of cleanups to "hide" the debugging code, it should now be much less intrusive visually - kernel/mutex.c is now both smaller and easier to read. There's no reduction in debugging functionality.
- cleaned up the debugging code
- unified all the externally visible debugging functions around the mutex_debug_ prefix.
- added the proper atomic ops to every architecture - so in theory mutexes should now work on every architectures. i386, x86_64 and ia64 was tested.
- created mutex-debug.h to hide some of the debugging details. Moved the mm.h and sched.h debug-function declarations into this file.
- documentation updates
- eliminated the ->file, ->line debugging variant - __FUNCTION__ is good enough and resulted in nicer code.
- properly check for held locks in kfree() too, if DEBUG.
- check for held-lock reinitialization via mutex_init(), if DEBUG.
- more micro-optimizations: eliminated an extra spinlock drop/reacquire in the slowpath.
- dropped waiter->woken, profiles showed that it triggered very rarely.
- dropped the timeout/timer bits - nothing is using them right now, we can add them back later.
- new mutex_trylock() optimization on architectures that support cmpxchg.
- marked ->name as const
- fixed typo: CONFIG_DEBUG_MUTEXESS -> CONFIG_DEBUG_MUTEXES
- mb() -> smp_mb() in mutex_is_locked()
- mutex_trylock doesnt need __sched
comments, fixes, bugreports are welcome,
Ingo