From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [GIT PULL] locking changes for v4.4
Date: Wed, 4 Nov 2015 17:01:04 +0100 [thread overview]
Message-ID: <20151104160104.GN17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CACT4Y+bPVaeSsJbpG2fsQ-C+zNoSnywTZZD1yPt-9hNY3tmgLQ@mail.gmail.com>
On Wed, Nov 04, 2015 at 03:51:01PM +0100, Dmitry Vyukov wrote:
> To clarify, yes, documentation and tooling was my main motivation.
Right; I don't object to having _ctrl() methods purely for documentation
purposes, I keep finding places we rely on them. Having them stand out
better might be useful.
> It is usually helpful to see acquire/release, rmb/wmb pairs, and so it
> is useful to know that something below is ordered wrt this load by
> means of a control dependency (which effectively becomes an acquire,
> and there must be a pairing release somewhere).
You need at least a trailing smp_rmb() before you cover the ACQUIRE
semantics -- or have no trailing reads at all of course.
next prev parent reply other threads:[~2015-11-04 16:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-03 9:16 [GIT PULL] locking changes for v4.4 Ingo Molnar
2015-11-03 23:54 ` Linus Torvalds
2015-11-03 23:58 ` Linus Torvalds
2015-11-04 1:30 ` Linus Torvalds
2015-11-04 4:16 ` Paul E. McKenney
2015-11-04 14:51 ` Dmitry Vyukov
2015-11-04 16:01 ` Peter Zijlstra [this message]
2015-11-04 16:09 ` Dmitry Vyukov
2015-11-04 11:37 ` Peter Zijlstra
2015-11-04 13:55 ` Paul E. McKenney
2015-11-04 11:48 ` Ingo Molnar
2015-11-04 13:54 ` Paul E. McKenney
2015-11-04 14:56 ` Ingo Molnar
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