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Date: Thu, 06 Aug 2009 09:11:29 -0400
From: Rik van Riel <riel@redhat.com>
Organization: Red Hat, Inc
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To: Wu Fengguang <fengguang.wu@intel.com>
CC: Andrea Arcangeli <aarcange@redhat.com>, Avi Kivity <avi@redhat.com>,
       "Dike, Jeffrey G" <jeffrey.g.dike@intel.com>,
       "Yu, Wilfred" <wilfred.yu@intel.com>,
       "Kleen, Andi" <andi.kleen@intel.com>,
       Hugh Dickins <hugh.dickins@tiscali.co.uk>,
       Andrew Morton <akpm@linux-foundation.org>,
       Christoph Lameter <cl@linux-foundation.org>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Mel Gorman <mel@csn.ul.ie>, LKML <linux-kernel@vger.kernel.org>,
       linux-mm <linux-mm@kvack.org>
Subject: Re: [RFC] respect the referenced bit of KVM guest pages?
References: <20090805024058.GA8886@localhost> <20090805155805.GC23385@random.random> <20090806100824.GO23385@random.random> <4A7AAE07.1010202@redhat.com> <20090806102057.GQ23385@random.random> <20090806105932.GA1569@localhost>
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Wu Fengguang wrote:

> This is a quick hack to materialize the idea. It remembers roughly
> the last 32*SWAP_CLUSTER_MAX=1024 active (mapped) pages scanned,
> and if _all of them_ are referenced, then the referenced bit is
> probably meaningless and should not be taken seriously.

This has the potential to increase the number of active
pages scanned by almost a factor 1024.  Let me whip up an
alternative idea when I get to the office later today.

-- 
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