From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S932699AbXCOTJO@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S932699AbXCOTJO (ORCPT <rfc822;w@1wt.eu>);
	Thu, 15 Mar 2007 15:09:14 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932574AbXCOTIr
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Thu, 15 Mar 2007 15:08:47 -0400
Received: from smtp.osdl.org ([65.172.181.24]:36719 "EHLO smtp.osdl.org"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751308AbXCOTIL (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Thu, 15 Mar 2007 15:08:11 -0400
Date: Thu, 15 Mar 2007 11:07:35 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Ashif Harji <asharji@cs.uwaterloo.ca>
Cc: dingxn@cse.ohio-state.edu, shaggy@linux.vnet.ibm.com,
       andi@rhlx01.fht-esslingen.de, linux-mm@kvack.org, npiggin@suse.de,
       jack@suse.cz, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/filemap.c: unconditionally call mark_page_accessed
Message-Id: <20070315110735.287c8a23.akpm@linux-foundation.org>
In-Reply-To: <Pine.GSO.4.64.0703150045550.18191@cpu102.cs.uwaterloo.ca>
References: <Pine.GSO.4.64.0703081612290.1080@cpu102.cs.uwaterloo.ca>
	<20070312142012.GH30777@atrey.karlin.mff.cuni.cz>
	<20070312143900.GB6016@wotan.suse.de>
	<20070312151355.GB23532@duck.suse.cz>
	<Pine.GSO.4.64.0703121247210.7679@cpu102.cs.uwaterloo.ca>
	<20070312173500.GF23532@duck.suse.cz>
	<Pine.GSO.4.64.0703131438580.8193@cpu102.cs.uwaterloo.ca>
	<20070313185554.GA5105@duck.suse.cz>
	<Pine.GSO.4.64.0703141218530.28958@cpu102.cs.uwaterloo.ca>
	<1173905741.8763.36.camel@kleikamp.austin.ibm.com>
	<20070314213317.GA22234@rhlx01.hs-esslingen.de>
	<1173910138.8763.45.camel@kleikamp.austin.ibm.com>
	<45F8A301.90301@cse.ohio-state.edu>
	<Pine.GSO.4.64.0703150045550.18191@cpu102.cs.uwaterloo.ca>
X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

> On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <asharji@cs.uwaterloo.ca> wrote:
> I still think the simple fix of removing the 
> condition is the best approach, but I'm certainly open to alternatives.

Yes, the problem of falsely activating pages when the file is read in small
hunks is worse than the problem which your patch fixes.

We could change it so that if the current read() includes the zeroeth byte
of the page, we run mark_page_accessed() even if this_page==prev_page?