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Date: Thu, 23 Dec 2010 14:18:38 -0800 (PST)
From: David Rientjes <rientjes@google.com>
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To: Mel Gorman <mel@csn.ul.ie>, Greg Kroah-Hartman <gregkh@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>
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        Christoph Lameter <cl@linux.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter
 threshold when memory is low
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On Mon, 29 Nov 2010, Mel Gorman wrote:

> Andrew, this patch was a performance fix but is a report saying that it
> fixes a functional regression in Fedora enough to push a patch torwards
> stable even though an explanation as to *why* it fixes the problem is missing?
> 

We had to pull aa454840 "mm: page allocator: calculate a better estimate 
of NR_FREE_PAGES when memory is low and kswapd is awake" from 2.6.36 
internally because tests showed that it would cause the machine to stall 
as the result of heavy kswapd activity.  I merged it back with this fix as 
it is pending in the -mm tree and it solves the issue we were seeing, so I 
definitely think this should be pushed to -stable (and I would seriously 
consider it for 2.6.37 inclusion even at this late date).