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Date: Wed, 10 Sep 2008 10:08:07 -0700
From: "Ray Lee" <ray-lk@madrabbit.org>
To: hamid.jahanjou@gmail.com
Subject: Re: [PATCH] VM: Implements the swap-out page-clustering technique
Cc: "Rik van Riel" <riel@redhat.com>, "Zan Lynx" <zlynx@acm.org>,
       "Andi Kleen" <andi@firstfloor.org>, linux-kernel@vger.kernel.org
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On Wed, Sep 10, 2008 at 1:16 AM, Hamid R. Jahanjou
<hamid.jahanjou@gmail.com> wrote:
> I agree. As you said, we have two conflicting requirements here: on the
> one hand one likes to swap as many pages as to satisfy the backing
> storage "proper block IO size," on the other hand, one should not make a
> process lose too many pages.

I'd much rather that one process lose a lot of pages than many
processes lose a few. When a system is swap thrashing, each process
has some of its active working set tossed to swap, which means *any*
application you try to switch to is then sluggish. If it were only one
application, then only that one takes the penalty hit when the user
switches focus and context.