Subject: Re: [RFC] mmaped copy too slow?
From: Peter Zijlstra <peterz@infradead.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
In-Reply-To: <20080115115318.1191.KOSAKI.MOTOHIRO@jp.fujitsu.com>
References: <20080115100450.1180.KOSAKI.MOTOHIRO@jp.fujitsu.com>
	 <20080114211540.284df4fb@bree.surriel.com>
	 <20080115115318.1191.KOSAKI.MOTOHIRO@jp.fujitsu.com>
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Date: Tue, 15 Jan 2008 09:57:58 +0100
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On Tue, 2008-01-15 at 12:20 +0900, KOSAKI Motohiro wrote:
> Hi Rik
> 
> > While being able to deal with used-once mappings in page reclaim
> > could be a good idea, this would require us to be able to determine
> > the difference between a page that was accessed once since it was
> > faulted in and a page that got accessed several times.
> 
> it makes sense that read ahead hit assume used-once mapping, may be.
> I will try it.

I once had a patch that made read-ahead give feedback into page reclaim,
but people didn't like it.

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