From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Daniel Lustig <dlustig@nvidia.com>,
Andrea Parri <parri.andrea@gmail.com>,
Luc Maranget <luc.maranget@inria.fr>,
Jade Alglave <j.alglave@ucl.ac.uk>,
Boqun Feng <boqun.feng@gmail.com>,
Nicholas Piggin <npiggin@gmail.com>,
Will Deacon <will.deacon@arm.com>,
David Howells <dhowells@redhat.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Unlock-lock questions and the Linux Kernel Memory Model
Date: Thu, 30 Nov 2017 08:39:09 -0800 [thread overview]
Message-ID: <20171130163909.GQ3624@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171130162501.cx5ha7nispozlf34@hirez.programming.kicks-ass.net>
On Thu, Nov 30, 2017 at 05:25:01PM +0100, Peter Zijlstra wrote:
> On Thu, Nov 30, 2017 at 08:14:01AM -0800, Paul E. McKenney wrote:
> > > (Also, technically speaking, the litmus test doesn't have any release
> > > operations, so no release sequence...)
> >
> > True! But if you translated it into C11, you would probably turn the
> > smp_wmb() followed by write into a store release, which would get you
> > a release sequence.
>
> smp_wmb()
> WRITE_ONCE(*y, 1);
>
> does not a RELEASE make.
Agreed, but it also does not C11 make. There is no pure write barrier
in C11.
Thanx, Paul
next prev parent reply other threads:[~2017-11-30 16:39 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4118cdbe-c396-08b9-a3e3-a0a6491b82fa@nvidia.com>
2017-11-27 21:16 ` Unlock-lock questions and the Linux Kernel Memory Model Alan Stern
2017-11-27 23:28 ` Daniel Lustig
2017-11-28 9:44 ` Peter Zijlstra
2017-11-28 9:58 ` Peter Zijlstra
2017-11-29 19:04 ` Daniel Lustig
2017-11-29 19:33 ` Paul E. McKenney
2017-11-29 19:44 ` Alan Stern
2017-11-30 8:55 ` Boqun Feng
2017-11-30 9:15 ` Peter Zijlstra
2017-11-30 15:46 ` Alan Stern
2017-12-01 2:46 ` Boqun Feng
2017-12-01 15:32 ` Alan Stern
2017-12-01 16:17 ` Daniel Lustig
2017-12-01 16:24 ` Will Deacon
2017-12-01 17:18 ` Alan Stern
2017-11-29 19:46 ` Peter Zijlstra
2017-11-29 19:53 ` Alan Stern
2017-11-29 20:42 ` Paul E. McKenney
2017-11-29 22:18 ` Daniel Lustig
2017-11-29 22:59 ` Paul E. McKenney
2017-11-30 15:20 ` Alan Stern
2017-11-30 16:14 ` Paul E. McKenney
2017-11-30 16:25 ` Peter Zijlstra
2017-11-30 16:39 ` Paul E. McKenney [this message]
2017-11-30 16:41 ` Will Deacon
2017-11-30 16:54 ` Paul E. McKenney
2017-11-30 17:04 ` Will Deacon
2017-11-30 17:56 ` Alan Stern
2017-11-30 10:02 ` Will Deacon
2017-11-29 19:58 ` Peter Zijlstra
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