Messages in this thread | | | Subject | Re: RFC: mutex: hung tasks on SMP platforms with asm-generic/mutex-xchg.h | From | Peter Zijlstra <> | Date | Mon, 13 Aug 2012 10:15:04 +0200 |
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On Thu, 2012-08-09 at 12:57 -0400, Nicolas Pitre wrote: > > In other words, I think this should look like this: > > diff --git a/include/asm-generic/mutex-xchg.h b/include/asm-generic/mutex-xchg.h > index 580a6d35c7..44a66c99c8 100644 > --- a/include/asm-generic/mutex-xchg.h > +++ b/include/asm-generic/mutex-xchg.h > @@ -25,8 +25,11 @@ > static inline void > __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) > { > - if (unlikely(atomic_xchg(count, 0) != 1)) > - fail_fn(count); > + if (unlikely(atomic_xchg(count, 0) != 1)) { > + /* Mark lock contention explicitly */ > + if (likely(atomic_xchg(count, -1) != 1)) > + fail_fn(count); > + } > }
OK, I like this.. Thanks guys! Will will you send a final and complete patch?
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