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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Christoph Lameter <cl@linux-foundation.org>
Subject: Re: [PATCH -mm] vmscan: protect a fraction of file backed mapped pages from reclaim
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       Andrew Morton <akpm@linux-foundation.org>,
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Date: Fri, 15 May 2009 08:28:02 +0900 (JST)
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> On Wed, 13 May 2009, KOSAKI Motohiro wrote:
> 
> > > All these expiration modifications do not take into account that a desktop
> > > may sit idle for hours while some other things run in the background (like
> > > backups at night or updatedb and other maintenance things). This still
> > > means that the desktop will be usuable in the morning.
> >
> > Have you seen this phenomenom?
> > I always use linux desktop for development. but I haven't seen it.
> > perhaps I have no luck. I really want to know reproduce way.
> >
> > Please let me know reproduce way.
> 
> Run a backup (or rsync) over a few hundred GB.

-ENOTREPRODUCED

umm.
May I ask detail operation?


> > > The percentage of file backed pages protected is set via
> > > /proc/sys/vm/file_mapped_ratio. This defaults to 20%.
> >
> > Why do you think typical mapped ratio is less than 20% on desktop machine?
> 
> Observation of the typical mapped size of Firefox under KDE.

My point is, desktop people have very various mapped ratio.
Do you oppose this?


> > key point is access-once vs access-many.
> 
> Nothing against it if it works.
>