Commit-ID: cc189d2513d1f45cde87a9043fe3be28559c7490 Gitweb: http://git.kernel.org/tip/cc189d2513d1f45cde87a9043fe3be28559c7490 Author: Waiman Long <[email protected]> AuthorDate: Wed, 17 Apr 2013 15:23:14 -0400 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 19 Apr 2013 09:33:36 +0200
mutex: Back out architecture specific check for negative mutex count Linus suggested that probably all the supported architectures can allow a negative mutex count without incorrect behavior, so we can then back out the architecture specific change and allow the mutex count to go to any negative number. That should further reduce contention for non-x86 architecture. Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Waiman Long <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Chandramouleeswaran Aswin <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Norton Scott J <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: David Howells <[email protected]> Cc: Dave Jones <[email protected]> Cc: Clark Williams <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/mutex.h | 10 ---------- kernel/mutex.c | 9 ++------- 2 files changed, 2 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/mutex.h b/arch/x86/include/asm/mutex.h index bc2a0b0..7d3a482 100644 --- a/arch/x86/include/asm/mutex.h +++ b/arch/x86/include/asm/mutex.h @@ -3,13 +3,3 @@ #else # include <asm/mutex_64.h> #endif - -#ifndef __ASM_MUTEX_H -#define __ASM_MUTEX_H -/* - * For the x86 architecture, it allows any negative number (besides -1) in - * the mutex count to indicate that some other threads are waiting on the - * mutex. - */ -#define __ARCH_ALLOW_ANY_NEGATIVE_MUTEX_COUNT 1 -#endif diff --git a/kernel/mutex.c b/kernel/mutex.c index 1dbd421..ad53a66 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -38,15 +38,10 @@ #endif /* - * A mutex count of -1 indicates that waiters are sleeping waiting for the - * mutex. Some architectures can allow any negative number, not just -1, for - * this purpose. + * A negative mutex count indicates that waiters are sleeping waiting for the + * mutex. */ -#ifdef __ARCH_ALLOW_ANY_NEGATIVE_MUTEX_COUNT #define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0) -#else -#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) != -1) -#endif void __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
