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From: Johan Hovold <johan@kernel.org>
To: "Paul E. McKenney" <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	LKMM Maintainers -- Akira Yokosawa <akiyks@gmail.com>,
	Andrea Parri <andrea.parri@amarulasolutions.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	David Howells <dhowells@redhat.com>,
	Daniel Lustig <dlustig@nvidia.com>,
	Jade Alglave <j.alglave@ucl.ac.uk>,
	Kernel development list <linux-kernel@vger.kernel.org>,
	Luc Maranget <luc.maranget@inria.fr>,
	Alan Stern <stern@rowland.harvard.edu>,
	Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH] Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()
Date: Mon, 29 Apr 2019 11:24:30 +0200	[thread overview]
Message-ID: <20190429092430.GF26546@localhost> (raw)
In-Reply-To: <20190423133010.GK3923@linux.ibm.com>

On Tue, Apr 23, 2019 at 06:30:10AM -0700, Paul E. McKenney wrote:
> On Tue, Apr 23, 2019 at 02:32:09PM +0200, Peter Zijlstra wrote:
> > On Sat, Apr 20, 2019 at 01:54:40AM -0700, Paul E. McKenney wrote:

> > > 	And lock acquisition??? acm_read_bulk_callback().
> > 
> > I think it goes with the set_bit() earlier, but what do I know.
> 
> Quite possibly!  In that case it should be smp_mb__after_atomic(),
> and it would be nice if it immediately followed the set_bit().

I noticed this one last week as well. The set_bit() had been incorrectly
moved and without noticing the smp_mb__before_atomic(). I've submitted a
patch to restore it and to fix a related issue to due missing barriers:

	https://lkml.kernel.org/r/20190425160540.10036-5-johan@kernel.org

Johan

  parent reply	other threads:[~2019-04-29  9:24 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-19 17:21 [PATCH] Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic() Alan Stern
2019-04-19 17:54 ` Paul E. McKenney
2019-04-19 18:00 ` Peter Zijlstra
2019-04-19 18:26   ` Paul E. McKenney
2019-04-20  0:26     ` Nicholas Piggin
2019-04-20  8:54       ` Paul E. McKenney
2019-04-23 12:17         ` Peter Zijlstra
2019-04-23 13:21           ` Paul E. McKenney
2019-04-23 13:26             ` Peter Zijlstra
2019-04-23 20:16               ` Paul E. McKenney
2019-04-23 20:28                 ` Peter Zijlstra
2019-04-24  8:29                   ` Paul E. McKenney
2019-04-24  8:44                     ` Peter Zijlstra
2019-04-23 12:32         ` Peter Zijlstra
2019-04-23 13:30           ` Paul E. McKenney
2019-04-23 13:40             ` Peter Zijlstra
2019-04-23 20:19               ` Paul E. McKenney
2019-04-27  8:17             ` Andrea Parri
2019-04-27  8:36               ` Paul E. McKenney
2019-04-29  9:24             ` Johan Hovold [this message]
2019-04-29 14:49               ` Paul E. McKenney

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