From: a.p.zijlstra@chello.nl (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: RFC: mutex: hung tasks on SMP platforms with asm-generic/mutex-xchg.h
Date: Mon, 13 Aug 2012 10:15:04 +0200 [thread overview]
Message-ID: <1344845704.31459.11.camel@twins> (raw)
In-Reply-To: <alpine.LFD.2.02.1208091243080.5231@xanadu.home>
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?
next prev parent reply other threads:[~2012-08-13 8:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-07 11:56 RFC: mutex: hung tasks on SMP platforms with asm-generic/mutex-xchg.h Will Deacon
2012-08-07 13:48 ` Peter Zijlstra
2012-08-07 14:04 ` Will Deacon
2012-08-07 17:14 ` Nicolas Pitre
2012-08-07 17:33 ` Will Deacon
2012-08-07 17:38 ` Will Deacon
2012-08-07 18:28 ` Nicolas Pitre
2012-08-09 5:12 ` Nicolas Pitre
2012-08-09 14:49 ` Will Deacon
2012-08-09 16:17 ` Nicolas Pitre
2012-08-09 16:57 ` Nicolas Pitre
2012-08-09 17:50 ` Will Deacon
2012-08-09 18:09 ` Nicolas Pitre
2012-08-09 18:17 ` Will Deacon
2012-08-09 20:05 ` Nicolas Pitre
2012-08-13 8:15 ` Peter Zijlstra [this message]
2012-08-13 9:13 ` Will Deacon
2012-08-13 13:35 ` Nicolas Pitre
2012-08-13 14:05 ` Peter Zijlstra
2012-08-13 14:11 ` Will Deacon
2012-08-13 14:45 ` Peter Zijlstra
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