From mboxrd@z Thu Jan  1 00:00:00 1970
Subject: Re: broken VM in 2.4.10-pre9
Date: Thu, 20 Sep 2001 13:57:02 +0100 (BST)
In-Reply-To: <20010920112110Z16256-2757+869@humbolt.nl.linux.org> from "Daniel Phillips" at Sep 20, 2001 01:28:31 PM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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To: Daniel Phillips <phillips@bonn-fries.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, "Eric W. Biederman" <ebiederm@xmission.com>, Rob Fuller <rfuller@nsisoftware.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>

> On September 20, 2001 12:04 am, Alan Cox wrote:
> > Reverse mappings make linear aging easier to do but are not critical (we
> > can walk all physical pages via the page map array).
>
> But you can't pick up the referenced bit that way, so no up aging, only
> down.

#1 If you really wanted to you could update a referenced bit in the page
struct in the fault handling path.

#2 If a page is referenced multiple times by different processes is the
behaviour of multiple upward aging actually wrong.

Alan

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