From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@gentwo.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
linux-kernel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH RFC] percpu: add data dependency barrier in percpu accessors and operations
Date: Tue, 17 Jun 2014 12:05:08 -0400 [thread overview]
Message-ID: <20140617160508.GF31819@htj.dyndns.org> (raw)
In-Reply-To: <20140617160040.GE31819@htj.dyndns.org>
On Tue, Jun 17, 2014 at 12:00:40PM -0400, Tejun Heo wrote:
> Hello, Christoph.
>
> On Tue, Jun 17, 2014 at 10:56:10AM -0500, Christoph Lameter wrote:
> > Uhhh no. The percpu stuff and the associated per cpu atomics are to be
> > used for stuff that is per cpu specific and runs at the fastest speed
> > doable at that level. Introducing implicit barriers is not that good an
> > idea.
>
> Hmmm? Read barriers are noops on all archs except for alpha and
Oops, data dependency barriers, not read barrier.
> percpu pointer assignments aren't exactly a high frequency operation
> and I'm pretty sure we'll end up with a raw variant anyway.
--
tejun
next prev parent reply other threads:[~2014-06-17 16:05 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-12 13:56 Tejun Heo
2014-06-12 15:34 ` Paul E. McKenney
2014-06-12 15:52 ` Tejun Heo
2014-06-17 14:41 ` Paul E. McKenney
2014-06-17 15:27 ` Tejun Heo
2014-06-17 15:56 ` Christoph Lameter
2014-06-17 16:00 ` Tejun Heo
2014-06-17 16:05 ` Tejun Heo [this message]
2014-06-17 16:28 ` Christoph Lameter
[not found] ` <CA+55aFxHr8JXwDR-4g4z1mkXvZRtY=OosYcUMPZRD2upfooS1w@mail.gmail.com>
2014-06-17 18:47 ` Christoph Lameter
2014-06-17 18:55 ` Paul E. McKenney
2014-06-17 19:39 ` Christoph Lameter
2014-06-17 19:47 ` Tejun Heo
2014-06-17 19:56 ` Paul E. McKenney
2014-06-19 20:39 ` Christoph Lameter
2014-06-17 16:57 ` Paul E. McKenney
2014-06-17 18:56 ` Tejun Heo
2014-06-17 19:42 ` Christoph Lameter
2014-06-17 20:44 ` Tejun Heo
2014-07-09 0:55 ` Rusty Russell
2014-07-14 11:39 ` Paul E. McKenney
2014-07-14 15:22 ` Christoph Lameter
2014-07-15 10:11 ` Paul E. McKenney
2014-07-15 14:06 ` Christoph Lameter
2014-07-15 14:32 ` Paul E. McKenney
2014-07-15 15:06 ` Christoph Lameter
2014-07-15 15:41 ` Linus Torvalds
2014-07-15 16:12 ` Christoph Lameter
[not found] ` <CA+55aFxU166V5-vH4vmK9OBdTZKyede=71RjjbOVSN9Qh+Se+A@mail.gmail.com>
2014-07-15 17:45 ` Paul E. McKenney
2014-07-15 17:41 ` Paul E. McKenney
2014-07-16 14:40 ` Christoph Lameter
2014-07-15 11:50 ` Rusty Russell
2014-06-17 19:27 ` Christoph Lameter
2014-06-17 19:40 ` Paul E. McKenney
2014-06-19 20:42 ` Christoph Lameter
2014-06-19 20:46 ` Tejun Heo
2014-06-19 21:11 ` Christoph Lameter
2014-06-19 21:15 ` Tejun Heo
2014-06-20 15:23 ` Christoph Lameter
2014-06-20 15:52 ` Tejun Heo
2014-06-19 20:51 ` Paul E. McKenney
2014-06-20 15:29 ` Christoph Lameter
2014-06-20 15:50 ` Paul E. McKenney
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