From: David Rientjes <rientjes@google.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Miao Xie <miaox@cn.fujitsu.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpuset: mm: Remove memory barrier damage from the page allocator
Date: Tue, 6 Mar 2012 15:31:22 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1203061529480.18656@chino.kir.corp.google.com> (raw)
In-Reply-To: <20120305094411.GD3481@suse.de>
On Mon, 5 Mar 2012, Mel Gorman wrote:
> > It's very expensive even without memory barriers since the page allocator
> > wraps itself in {get,put}_mems_allowed() until a page or NULL is returned
> > and an update to current's set of allowed mems can stall indefinitely
> > trying to change the nodemask during this time.
>
> Hmm, this sounds problematic. Are you seeing a problem with the behaviour
> with the patch applied or the existing behaviour?
>
Sorry, yes, this is with the existing behavior prior to your patch. We
definitely need fixes for get_mems_allowed() because it's possible that a
write to cpuset.mems will never return even when trying to add nodes to
its nodemask in oom conditions if one of the cpuset's tasks is looping
forever in the page allocator.
I'll review your updated version posted from today.
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next prev parent reply other threads:[~2012-03-06 23:31 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-02 11:23 Mel Gorman
2012-03-02 16:19 ` Christoph Lameter
2012-03-02 17:43 ` Mel Gorman
2012-03-02 19:53 ` Christoph Lameter
2012-03-02 21:25 ` Peter Zijlstra
2012-03-02 23:47 ` David Rientjes
2012-03-05 9:44 ` Mel Gorman
2012-03-06 23:31 ` David Rientjes [this message]
2012-03-05 9:35 ` Mel Gorman
2012-03-02 21:21 ` Peter Zijlstra
2012-03-05 20:18 ` Andrew Morton
2012-03-06 2:01 ` [RFC PATCH] checkpatch: Warn on use of yield() Joe Perches
2012-03-06 12:45 ` Peter Zijlstra
2012-03-06 13:14 ` Glauber Costa
2012-03-06 13:25 ` Peter Zijlstra
2012-03-06 13:27 ` Glauber Costa
2012-03-06 17:41 ` Joe Perches
2012-03-06 17:54 ` Peter Zijlstra
2012-03-06 18:00 ` Joe Perches
2012-03-06 18:17 ` Joe Perches
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