From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: David Howells <dhowells@redhat.com>
Cc: linux-kernel@vger.kernel.org, mark.rutland@arm.com,
linux-arch@vger.kernel.org, viro@zeniv.linux.org.uk,
tj@kernel.org, cl@linux.com, davem@davemloft.net,
peterz@infradead.org, mingo@redhat.com, rostedt@goodmis.org,
akpm@linux-foundation.org, corbet@lwn.net,
james.l.morris@oracle.com, torvalds@linux-foundation.org
Subject: Re: [PATCH RFC tip/core/rcu 0/15] Remove to-be-unneeded smp_read_barrier_depends()
Date: Wed, 11 Oct 2017 05:56:36 -0700 [thread overview]
Message-ID: <20171011125636.GX3521@linux.vnet.ibm.com> (raw)
In-Reply-To: <26479.1507724463@warthog.procyon.org.uk>
On Wed, Oct 11, 2017 at 01:21:03PM +0100, David Howells wrote:
> Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
>
> > Will Deacon has proposed adding smp_read_barrier_depends() to READ_ONCE(),
> > which would mean that quite a few instances of smp_read_barrier_depends()
> > would become redundant.
>
> It's not clear from you description where the barrier is added in relation to
> the read: before, after or both?
After, similar to lockless_dereference(). Of course, there is not
really a barrier except for on Alpha.
Thanx, Paul
prev parent reply other threads:[~2017-10-11 12:56 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-10 0:19 [PATCH RFC tip/core/rcu 0/15] Remove to-be-unneeded smp_read_barrier_depends() Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 01/15] doc: READ_ONCE() now implies smp_barrier_depends() Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 02/15] mn10300: READ_ONCE() now implies smp_read_barrier_depends() Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 03/15] drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 04/15] fs/dcache: Use release-acquire for name/length update Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 05/15] percpu: READ_ONCE() now implies smp_read_barrier_depends() Paul E. McKenney
2017-10-10 14:08 ` Tejun Heo
2017-10-10 15:30 ` Paul E. McKenney
2017-10-10 15:49 ` Tejun Heo
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 06/15] rcu: Adjust read-side accessor comments for READ_ONCE() Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 07/15] rtnetlink: Update now-misleading smp_read_barrier_depends() comment Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 08/15] seqlock: Remove now-redundant smp_read_barrier_depends() Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 09/15] uprobes: " Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 10/15] locking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath() Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 11/15] tracepoint: Remove smp_read_barrier_depends() from comment Paul E. McKenney
2017-10-10 0:31 ` Steven Rostedt
2017-10-10 1:12 ` Mathieu Desnoyers
2017-10-10 15:32 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 12/15] lib/assoc_array: Remove smp_read_barrier_depends() Paul E. McKenney
2017-10-10 8:39 ` Peter Zijlstra
2017-10-10 9:36 ` David Howells
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 13/15] mm/ksm: Remove now-redundant smp_read_barrier_depends() Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 14/15] netfilter: " Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 8:43 ` Peter Zijlstra
2017-10-10 15:56 ` Paul E. McKenney
2017-10-10 0:22 ` [PATCH RFC tip/core/rcu 15/15] keyring: " Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 0:22 ` Paul E. McKenney
2017-10-10 9:35 ` [PATCH RFC tip/core/rcu 12/15] lib/assoc_array: Remove smp_read_barrier_depends() David Howells
2017-10-10 15:50 ` Paul E. McKenney
2017-10-10 15:54 ` Peter Zijlstra
2017-10-10 16:05 ` Paul E. McKenney
2017-10-11 12:19 ` David Howells
2017-10-11 12:22 ` Will Deacon
2017-10-11 12:54 ` Paul E. McKenney
2017-10-11 14:18 ` Will Deacon
2017-10-11 14:50 ` Paul E. McKenney
2017-10-11 12:58 ` Paul E. McKenney
2017-10-11 15:17 ` David Howells
2017-10-11 15:59 ` Paul E. McKenney
2017-10-11 16:12 ` Peter Zijlstra
2017-10-11 16:24 ` Peter Zijlstra
2017-10-11 16:47 ` Paul E. McKenney
2017-10-11 16:54 ` Peter Zijlstra
2017-10-11 17:06 ` Paul E. McKenney
2017-10-11 17:11 ` Peter Zijlstra
2017-10-11 17:34 ` Paul E. McKenney
2017-10-11 18:43 ` Dmitry Vyukov
2017-10-11 18:56 ` Linus Torvalds
2017-10-11 19:28 ` Paul E. McKenney
2017-10-11 19:59 ` Dmitry Vyukov
2017-10-11 17:14 ` Paul E. McKenney
2017-10-11 17:19 ` Mark Rutland
2017-10-11 16:50 ` Paul E. McKenney
2017-10-11 16:07 ` David Howells
2017-10-11 16:17 ` Peter Zijlstra
2017-10-11 16:19 ` Paul E. McKenney
2017-10-11 15:28 ` David Howells
2017-10-11 16:02 ` Paul E. McKenney
2017-10-10 9:59 ` David Howells
2017-10-10 15:52 ` Paul E. McKenney
2017-10-11 12:21 ` [PATCH RFC tip/core/rcu 0/15] Remove to-be-unneeded smp_read_barrier_depends() David Howells
2017-10-11 12:56 ` Paul E. McKenney [this message]
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