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Date: Fri, 9 Nov 2012 09:06:35 +0000
From: Mel Gorman <mgorman@suse.de>
Subject: Re: kswapd0: excessive CPU usage
Message-ID: <20121109090635.GG8218@suse.de>
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To: Zdenek Kabelac <zkabelac@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>, Jiri Slaby <jslaby@suse.cz>, Valdis.Kletnieks@vt.edu, Jiri Slaby <jirislaby@gmail.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Robert Jennings <rcj@linux.vnet.ibm.com>

On Fri, Nov 09, 2012 at 09:07:45AM +0100, Zdenek Kabelac wrote:
> >fe2c2a106663130a5ab45cb0e3414b52df2fff0c is the first bad commit
> >commit fe2c2a106663130a5ab45cb0e3414b52df2fff0c
> >Author: Rik van Riel <riel@redhat.com>
> >Date:   Wed Mar 21 16:33:51 2012 -0700
> >
> >     vmscan: reclaim at order 0 when compaction is enabled
> >...
> >
> >This is plausible since the issue seems to be in the kswapd + compaction
> >realm.  I've yet to figure out exactly what about this commit results in
> >kswapd spinning.
> >
> >I would be interested if someone can confirm this finding.
> >
> >--
> >Seth
> >
> 
> 
> On my system 3.7-rc4 the problem seems to be effectively solved by
> revert patch: https://lkml.org/lkml/2012/11/5/308
> 

Ok, while there is still a question on whether it's enough I think it's
sensible to at least start with the obvious one.

Thanks very much.

-- 
Mel Gorman
SUSE Labs

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