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Date: Fri, 7 Aug 2009 13:24:34 +0530
Message-ID: <661de9470908070054l2fa99ac6w6cac2be63cd5d91f@mail.gmail.com>
Subject: Re: [RFC] respect the referenced bit of KVM guest pages?
From: Balbir Singh <balbir@linux.vnet.ibm.com>
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To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>, Avi Kivity <avi@redhat.com>, Wu Fengguang <fengguang.wu@intel.com>, Andrea Arcangeli <aarcange@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>, Mel Gorman <mel@csn.ul.ie>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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On Fri, Aug 7, 2009 at 8:41 AM, KOSAKI
Motohiro<kosaki.motohiro@jp.fujitsu.com> wrote:
> (cc to memcg folks)
>
>> Avi Kivity wrote:
>> > On 08/06/2009 01:59 PM, Wu Fengguang wrote:
>>
>> >> As a refinement, the static variable 'recent_all_referenced' could be
>> >> moved to struct zone or made a per-cpu variable.
>> >
>> > Definitely this should be made part of the zone structure, consider the
>> > original report where the problem occurs in a 128MB zone (where we can
>> > expect many pages to have their referenced bit set).
>>
>> The problem did not occur in a 128MB zone, but in a 128MB cgroup.
>>
>> Putting it in the zone means that the cgroup, which may have
>> different behaviour from the rest of the zone, due to excessive
>> memory pressure inside the cgroup, does not get the right
>> statistics.
>
> maybe, I heven't catch your point.
>
> Current memcgroup logic also use recent_scan/recent_rotate statistics.
> Isn't it enought?

I don't understand the context, I'll look at the problem when I am
back (I am away from work for the next few days).

Balbir

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