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Date: Wed, 5 May 2010 16:32:49 +0100
From: Mel Gorman <mel@csn.ul.ie>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Christoph Lameter <cl@linux-foundation.org>,
       Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
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       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Rik van Riel <riel@redhat.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH] fix count_vm_event preempt in memory compaction direct
	reclaim
Message-ID: <20100505153249.GR20979@csn.ul.ie>
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On Wed, May 05, 2010 at 05:25:31PM +0200, Andrea Arcangeli wrote:
> On Wed, May 05, 2010 at 04:14:39PM +0100, Mel Gorman wrote:
> > How about the following as an alternative to dropp migrate_prep?
> 
> Yep this is what I'd like too... btw in the comments you also mention
> IPI but I guess that's ok.

It was an oversight. I've corrected it now.

> About the cost I'm not sure but I would
> expect the cost of this to be even higher because it also has to run
> the scheduler unlike a real IPI.
> 

Fair point. I wouldn't be too sure what the relative costs are but either
way it's bad and unnecessary in the case of compaction.

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab