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2009-12-14locking: Implement new raw_spinlockThomas Gleixner1-6/+6
Now that the raw_spin name space is freed up, we can implement raw_spinlock and the related functions which are used to annotate the locks which are not converted to sleeping spinlocks in preempt-rt. A side effect is that only such locks can be used with the low level lock fsunctions which circumvent lockdep. For !rt spin_* functions are mapped to the raw_spin* implementations. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14locking: Convert __raw_spin* functions to arch_spin*Thomas Gleixner1-2/+2
Name space cleanup. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
2009-01-14mutex: implement adaptive spinningPeter Zijlstra1-8/+10
Change mutex contention behaviour such that it will sometimes busy wait on acquisition - moving its behaviour closer to that of spinlocks. This concept got ported to mainline from the -rt tree, where it was originally implemented for rtmutexes by Steven Rostedt, based on work by Gregory Haskins. Testing with Ingo's test-mutex application (http://lkml.org/lkml/2006/1/8/50) gave a 345% boost for VFS scalability on my testbox: # ./test-mutex-shm V 16 10 | grep "^avg ops" avg ops/sec: 296604 # ./test-mutex-shm V 16 10 | grep "^avg ops" avg ops/sec: 85870 The key criteria for the busy wait is that the lock owner has to be running on a (different) cpu. The idea is that as long as the owner is running, there is a fair chance it'll release the lock soon, and thus we'll be better off spinning instead of blocking/scheduling. Since regular mutexes (as opposed to rtmutexes) do not atomically track the owner, we add the owner in a non-atomic fashion and deal with the races in the slowpath. Furthermore, to ease the testing of the performance impact of this new code, there is means to disable this behaviour runtime (without having to reboot the system), when scheduler debugging is enabled (CONFIG_SCHED_DEBUG=y), by issuing the following command: # echo NO_OWNER_SPIN > /debug/sched_features This command re-enables spinning again (this is also the default): # echo OWNER_SPIN > /debug/sched_features Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2006-07-03[PATCH] lockdep: better lock debuggingIngo Molnar1-70/+12
Generic lock debugging: - generalized lock debugging framework. For example, a bug in one lock subsystem turns off debugging in all lock subsystems. - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from the mutex/rtmutex debugging code: it caused way too much prototype hackery, and lockdep will give the same information anyway. - ability to do silent tests - check lock freeing in vfree too. - more finegrained debugging options, to allow distributions to turn off more expensive debugging features. There's no separate 'held mutexes' list anymore - but there's a 'held locks' stack within lockdep, which unifies deadlock detection across all lock classes. (this is independent of the lockdep validation stuff - lockdep first checks whether we are holding a lock already) Here are the current debugging options: CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y which do: config DEBUG_MUTEXES bool "Mutex debugging, basic checks" config DEBUG_LOCK_ALLOC bool "Detect incorrect freeing of live mutexes" Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03[PATCH] lockdep: remove DEBUG_BUG_ON()Ingo Molnar1-8/+0
cleanup: remove unused DEBUG_BUG_ON() defines. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03[PATCH] lockdep: rename DEBUG_WARN_ON()Ingo Molnar1-7/+7
Rename DEBUG_WARN_ON() to the less generic DEBUG_LOCKS_WARN_ON() name, so that it's clear that this is a lock-debugging internal mechanism. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] work around ppc64 bootup bug by making mutex-debugging save/restore irqsIngo Molnar1-20/+5
It seems ppc64 wants to lock mutexes in early bootup code, with interrupts disabled, and they expect interrupts to stay disabled, else they crash. Work around this bug by making mutex debugging variants save/restore irq flags. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] mutex subsystem, debugging codeIngo Molnar1-0/+134
mutex implementation - add debugging code. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org>

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