Date: Thu, 4 Feb 2010 18:47:15 +0100
From: Andrea Arcangeli <aarcange@redhat.com>
To: Rik van Riel <riel@redhat.com>
Cc: balbir@linux.vnet.ibm.com, jdike@addtoit.com, kvm@vger.kernel.org,
       linux-kernel@vger.kernel.org, avi@redhat.com, mtosatti@redhat.com
Subject: Re: [PATCH] emulate accessed bit for EPT
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References: <20100203161103.11e2b572@annuminas.surriel.com>
 <20100204041212.GI19641@balbir.in.ibm.com>
 <4B6ACE5B.9080601@redhat.com>
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On Thu, Feb 04, 2010 at 08:40:43AM -0500, Rik van Riel wrote:
> I suspect it won't be very many. I have been monitoring
> /proc/meminfo on my system while testing this patch, and
> it is quite typical that the size of the inactive anon
> list does not change for minutes at a time.
> 
> In other words, no pages are moved onto or off of the
> inactive anon list for several minutes. That corresponds
> to a very small number of minor faults introduced by my
> patch.

When there's light VM pressure, ideally there should be zero overhead
caused by the patch. When there is VM pressure this will avoid some
unnecessary I/O which should outweight the minor faults. It should be
a good default behavior.
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