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Subject: Re: [PATCH] O_STREAMING - flag for optimal streaming I/O
From: Xavier Bestel <xavier.bestel@free.fr>
To: Helge Hafting <helgehaf@aitel.hist.no>
Cc: Giuliano Pochini <pochini@shiny.it>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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References: <XFMail.20021010113849.pochini@shiny.it> 
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Date: 10 Oct 2002 14:29:11 +0200
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Le jeu 10/10/2002 ? 13:01, Helge Hafting a ?crit :
> Giuliano Pochini wrote:
> 
> > Yes, it makes sense, but it's useless or harmful to discard caches
> > if nobody else needs memory. You just lose data that may be
> > requested in the future for no reason.
> 
> Sure, so the ideal is to not drop unconditionally, but
> make sure that the "finished" O_STREAMING pages are
> the very first ones to go whenever memory pressure happens.

IMHO this shoudln't be taken care of. As you say it, a linux box has no
free memory (or it's been very recently booted), so the problem is not
to make O_STREAMING pages "low priority", but just to make them not stay
in the cache (perhaps just keep a few KB worth of them in case of a
limited seek back, but not more).

	Xav

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