From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will.deacon@arm.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"Waiman.Long@hp.com" <Waiman.Long@hp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"paulmck@linux.vnet.ibm.com" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH v3 1/8] atomics: add acquire/release/relaxed variants of some atomic operations
Date: Mon, 27 Jul 2015 19:51:39 +0200 [thread overview]
Message-ID: <20150727175139.GZ19282@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150727163300.GL3358@arm.com>
On Mon, Jul 27, 2015 at 05:33:00PM +0100, Will Deacon wrote:
> Something like below?
>
> Will
>
> --->8
>
> diff --git a/include/linux/atomic.h b/include/linux/atomic.h
> index 899b4035569e..d2515c05e7c8 100644
> --- a/include/linux/atomic.h
> +++ b/include/linux/atomic.h
> @@ -14,6 +14,11 @@
> * - Release: Provides RELEASE semantics, _release suffix.
> * - Relaxed: No ordering guarantees, _relaxed suffix.
> *
> + * For compound atomics performing both a load and a store, ACQUIRE
> + * semantics apply only to the load and RELEASE semantics only to the
> + * store portion of the operation. Note that a failed cmpxchg_acquire
> + * does -not- imply any memory ordering constraints.
> + *
> * See Documentation/memory-barriers.txt for ACQUIRE/RELEASE definitions.
> */
Yep, works for me.
next prev parent reply other threads:[~2015-07-27 17:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-24 14:04 [PATCH v3 0/8] Add generic support for relaxed atomics Will Deacon
2015-07-24 14:04 ` [PATCH v3 1/8] atomics: add acquire/release/relaxed variants of some atomic operations Will Deacon
2015-07-27 9:14 ` Peter Zijlstra
2015-07-27 10:21 ` Will Deacon
2015-07-27 16:33 ` Will Deacon
2015-07-27 17:51 ` Peter Zijlstra [this message]
2015-07-24 14:04 ` [PATCH v3 2/8] asm-generic: rework atomic-long.h to avoid bulk code duplication Will Deacon
2015-07-24 14:04 ` [PATCH v3 3/8] asm-generic: add relaxed/acquire/release variants for atomic_long_t Will Deacon
2015-07-24 14:04 ` [PATCH v3 4/8] lockref: remove homebrew cmpxchg64_relaxed macro definition Will Deacon
2015-07-24 14:04 ` [PATCH v3 5/8] locking/qrwlock: implement queue_write_unlock using smp_store_release Will Deacon
2015-07-24 14:04 ` [PATCH v3 6/8] locking/qrwlock: make use of acquire/release/relaxed atomics Will Deacon
2015-07-24 14:04 ` [PATCH v3 7/8] include/llist: use linux/atomic.h instead of asm/cmpxchg.h Will Deacon
2015-07-24 14:04 ` [PATCH v3 8/8] ARM: atomics: define our SMP atomics in terms of _relaxed operations Will Deacon
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