From: Will Deacon <will.deacon@arm.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "Boqun Feng" <boqun.feng@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Maciej W. Rozycki" <macro@imgtec.com>,
"David Daney" <ddaney@caviumnetworks.com>,
"Måns Rullgård" <mans@mansr.com>,
"Ralf Baechle" <ralf@linux-mips.org>,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
Subject: Re: [RFC][PATCH] mips: Fix arch_spin_unlock()
Date: Tue, 2 Feb 2016 17:37:35 +0000 [thread overview]
Message-ID: <20160202173734.GN10166@arm.com> (raw)
In-Reply-To: <20160202171237.GL6719@linux.vnet.ibm.com>
On Tue, Feb 02, 2016 at 09:12:37AM -0800, Paul E. McKenney wrote:
> On Tue, Feb 02, 2016 at 12:20:25PM +0000, Will Deacon wrote:
> > On Tue, Feb 02, 2016 at 08:12:30PM +0800, Boqun Feng wrote:
> > > On Tue, Feb 02, 2016 at 11:45:59AM +0000, Will Deacon wrote:
> > > > Well, the following ISA2 test is permitted on ARM:
> > > >
> > > >
> > > > P0:
> > > > Wx=1
> > > > WyRel=1 // rcu_assign_pointer
> > > >
> > > > P1:
> > > > Ry=1 // rcu_dereference
> > >
> > > What if a <addr> dependency is added here? Same result?
> >
> > Right, that fixes it. So if we're only considering things like:
> >
> > rcu_dereference
> > <addr>
> > RELEASE
> >
> > then local transitivity should be preserved.
>
> Whew!!! ;-)
>
> > I think the same applies to <ctrl>, which seems to match your later
> > example.
>
> Could you please check?
I should've been more concrete here: it does indeed apply if you replace
the <addr> with a <ctrl> in the snippet above, I just hadn't got Boqun's
example paged in and didn't want to commit on the examples being identical.
Will
prev parent reply other threads:[~2016-02-02 17:37 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-12 12:31 [RFC][PATCH] mips: Fix arch_spin_unlock() Peter Zijlstra
2015-11-12 12:35 ` Peter Zijlstra
2015-11-12 13:31 ` Måns Rullgård
2015-11-12 14:32 ` Paul E. McKenney
2015-11-12 14:50 ` Måns Rullgård
2015-11-12 14:59 ` Paul E. McKenney
2015-11-12 17:46 ` David Daney
2015-11-12 18:00 ` Peter Zijlstra
2015-11-12 18:13 ` Måns Rullgård
2015-11-12 18:17 ` David Daney
2016-01-27 9:57 ` Maciej W. Rozycki
2016-01-27 11:43 ` Will Deacon
2016-01-27 12:41 ` Maciej W. Rozycki
2016-01-28 1:11 ` Boqun Feng
2016-01-27 14:54 ` Peter Zijlstra
2016-01-27 15:21 ` Will Deacon
2016-01-27 23:38 ` Paul E. McKenney
2016-01-28 9:57 ` Will Deacon
2016-01-28 22:31 ` Paul E. McKenney
2016-01-29 9:59 ` Will Deacon
2016-01-29 10:22 ` Paul E. McKenney
2016-02-01 13:56 ` Will Deacon
2016-02-02 3:54 ` Paul E. McKenney
2016-02-02 5:19 ` Boqun Feng
2016-02-02 6:44 ` Paul E. McKenney
2016-02-02 8:07 ` Linus Torvalds
2016-02-02 8:19 ` Linus Torvalds
2016-02-02 9:34 ` Boqun Feng
2016-02-02 17:30 ` Linus Torvalds
2016-02-02 17:51 ` Will Deacon
2016-02-02 18:06 ` Linus Torvalds
2016-02-02 19:30 ` Will Deacon
2016-02-02 19:55 ` Linus Torvalds
2016-02-03 19:13 ` Will Deacon
2016-02-03 8:33 ` Ingo Molnar
2016-02-03 13:32 ` Will Deacon
2016-02-03 19:03 ` Will Deacon
2016-02-09 11:23 ` Ingo Molnar
2016-02-09 11:42 ` Will Deacon
2016-02-02 12:02 ` Paul E. McKenney
2016-02-02 17:56 ` Linus Torvalds
2016-02-02 22:30 ` Paul E. McKenney
2016-02-02 14:49 ` Ralf Baechle
2016-02-02 14:54 ` Måns Rullgård
2016-02-02 14:58 ` Ralf Baechle
2016-02-02 15:51 ` Måns Rullgård
2016-02-02 17:23 ` Peter Zijlstra
2016-02-02 22:38 ` Paul E. McKenney
2016-02-02 11:45 ` Will Deacon
2016-02-02 12:12 ` Boqun Feng
2016-02-02 12:20 ` Will Deacon
2016-02-02 13:18 ` Boqun Feng
2016-02-02 17:12 ` Paul E. McKenney
2016-02-02 17:37 ` Will Deacon [this message]
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