From: Peter Zijlstra <peterz@infradead.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: f68f031d ("Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()")
Date: Fri, 3 May 2019 18:34:11 +0200 [thread overview]
Message-ID: <20190503163411.GH2606@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1905031216310.1437-100000@iolanthe.rowland.org>
On Fri, May 03, 2019 at 12:19:21PM -0400, Alan Stern wrote:
> On Fri, 3 May 2019, Peter Zijlstra wrote:
>
> > On Fri, May 03, 2019 at 07:53:26AM -0700, Paul E. McKenney wrote:
> > > Hello, Alan,
> > >
> > > Just following up on the -rcu commit below. I believe that it needs
> > > some adjustment given Peter Zijlstra's addition of "memory" to the x86
> > > non-value-returning atomics, but thought I should double-check.
> >
> > Right; I should get back to that thread...
>
> The real question, still outstanding, is whether smp_mb__before_atomic
> orders anything following the RMW instruction (and similarly, whether
> smp_mb__after_atomic orders anything preceding the RMW instruction).
Yes -- that was very much the intent, and only (some) x86 ops and (some)
MIPS config have issues with that.
next prev parent reply other threads:[~2019-05-03 16:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-03 14:53 f68f031d ("Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()") Paul E. McKenney
2019-05-03 15:19 ` Peter Zijlstra
2019-05-03 16:19 ` Alan Stern
2019-05-03 16:34 ` Peter Zijlstra [this message]
2019-05-03 16:52 ` Alan Stern
2019-05-03 17:13 ` [PATCH v2] Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic() Alan Stern
2019-05-06 16:42 ` Andrea Parri
2019-05-12 3:28 ` Paul E. McKenney
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