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2010-05-13rwsem: Test for no active locks in __rwsem_do_wake undo codeMichel Lespinasse
If there are no active threasd using a semaphore, it is always correct to unqueue blocked threads. This seems to be what was intended in the undo code. What was done instead, was to look for a sem count of zero - this is an impossible situation, given that at least one thread is known to be queued on the semaphore. The code might be correct as written, but it's hard to reason about and it's not what was intended (otherwise the goto out would have been unconditional). Go for checking the active count - the alternative is not worth the headache. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-30x86: fix UML and -regparm=3Ingo Molnar
introduce the "asmregparm" calling convention: for functions implemented in assembly with a fixed regparm input parameters calling convention. mark the semaphore and rwsem slowpath functions with that. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-12-18sched: mark rwsem functions as __sched for wchan/profilingLivio Soares
This following commit http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=fdf8cb0909b531f9ae8f9b9d7e4eb35ba3505f07 un-inlined a low-level rwsem function, but did not mark it as __sched. The result is that it now shows up as thread wchan (which also affects /proc/profile stats). The following simple patch fixes this by properly marking rwsem_down_failed_common() as a __sched function. Also in this patch, which is up for discussion, marks down_read() and down_write() proper as __sched. For profiling, it is pretty much useless to know that a semaphore is beig help - it is necessary to know _which_ one. By going up another frame on the stack, the information becomes much more useful. In summary, the below change to lib/rwsem.c should be applied; the changes to kernel/rwsem.c could be applied if other kernel hackers agree with my proposal that down_read()/down_write() in the profile is not enough. [ akpm@linux-foundation.org: build fix ] Signed-off-by: Livio Soares <livio@eecg.toronto.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2006-10-11Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass()Peter Zijlstra
This annotation makes it possible to assign a subclass on lock init. This annotation is meant to reduce the _nested() annotations by assigning a default subclass. One could do without this annotation and rely on lockdep_set_class() exclusively, but that would require a manual stack of struct lock_class_key objects. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2006-09-29[PATCH] lib/rwsem.c: un-inline rwsem_down_failed_common()Andreas Mohr
Un-inlining rwsem_down_failed_common() (two callsites) reduced lib/rwsem.o on my Athlon, gcc 4.1.2 from 5935 to 5480 Bytes (455 Bytes saved). I thus guess that reduced icache footprint (and better function caching) is worth more than any function call overhead. Signed-off-by: Andreas Mohr <andi@lisas.de> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03[PATCH] lockdep: prove rwsem locking correctnessIngo Molnar
Use the lock validator framework to prove rwsem locking correctness. 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: clean up rwsemsIngo Molnar
Clean up rwsems. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01[PATCH] use smp_mb/wmb/rmb where possibleakpm@osdl.org
Replace a number of memory barriers with smp_ variants. This means we won't take the unnecessary hit on UP machines. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!