From: Christoph Lameter <cl@linux-foundation.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Mike Galbraith <efault@gmx.de>, Ingo Molnar <mingo@elte.hu>,
linux-mm <linux-mm@kvack.org>,
Oleg Nesterov <onestero@redhat.com>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [rfc] lru_add_drain_all() vs isolation
Date: Wed, 9 Sep 2009 10:08:23 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0909091005010.28070@V090114053VZO-1> (raw)
In-Reply-To: <20090909131945.0CF5.A69D9226@jp.fujitsu.com>
On Wed, 9 Sep 2009, KOSAKI Motohiro wrote:
> Christoph, I'd like to discuss a bit related (and almost unrelated) thing.
> I think page migration don't need lru_add_drain_all() as synchronous, because
> page migration have 10 times retry.
True this is only an optimization that increases the chance of isolation
being successful. You dont need draining at all.
> Then asynchronous lru_add_drain_all() cause
>
> - if system isn't under heavy pressure, retry succussfull.
> - if system is under heavy pressure or RT-thread work busy busy loop, retry failure.
>
> I don't think this is problematic bahavior. Also, mlock can use asynchrounous lru drain.
>
> What do you think?
The retries can be very fast if the migrate pages list is small. The
migrate attempts may be finished before the IPI can be processed by the
other cpus.
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next prev parent reply other threads:[~2009-09-09 14:09 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <dgRNo-3uc-5@gated-at.bofh.it>
[not found] ` <dhb9j-1hp-5@gated-at.bofh.it>
[not found] ` <dhcf5-263-13@gated-at.bofh.it>
[not found] ` <36bbf267-be27-4c9e-b782-91ed32a1dfe9@g1g2000pra.googlegroups.com>
[not found] ` <1252218779.6126.17.camel@marge.simson.net>
[not found] ` <1252232289.29247.11.camel@marge.simson.net>
[not found] ` <DDFD17CC94A9BD49A82147DDF7D545C54DC482@exchange.ZeugmaSystems.local>
[not found] ` <1252249790.13541.28.camel@marge.simson.net>
[not found] ` <1252311463.7586.26.camel@marge.simson.net>
2009-09-07 11:06 ` Peter Zijlstra
2009-09-07 13:35 ` Oleg Nesterov
2009-09-07 13:53 ` Peter Zijlstra
2009-09-07 14:18 ` Oleg Nesterov
2009-09-07 14:25 ` Peter Zijlstra
2009-09-07 23:56 ` KOSAKI Motohiro
2009-09-08 8:20 ` Peter Zijlstra
2009-09-08 10:06 ` KOSAKI Motohiro
2009-09-08 10:20 ` Peter Zijlstra
2009-09-08 11:41 ` KOSAKI Motohiro
2009-09-08 12:05 ` Peter Zijlstra
2009-09-08 14:03 ` Christoph Lameter
2009-09-08 14:20 ` Peter Zijlstra
2009-09-08 15:22 ` Christoph Lameter
2009-09-08 15:27 ` Peter Zijlstra
2009-09-08 15:32 ` Christoph Lameter
2009-09-09 4:27 ` KOSAKI Motohiro
2009-09-09 14:08 ` Christoph Lameter [this message]
2009-09-09 23:43 ` KOSAKI Motohiro
2009-09-10 18:03 ` Christoph Lameter
2009-09-09 15:39 ` Minchan Kim
2009-09-09 16:18 ` Lee Schermerhorn
2009-09-09 16:46 ` Minchan Kim
2009-09-09 23:58 ` KOSAKI Motohiro
2009-09-10 1:00 ` Minchan Kim
2009-09-10 1:15 ` KOSAKI Motohiro
2009-09-10 1:23 ` Minchan Kim
2009-09-09 2:06 ` KOSAKI Motohiro
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