From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752053AbXBJWoy (ORCPT ); Sat, 10 Feb 2007 17:44:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752057AbXBJWoy (ORCPT ); Sat, 10 Feb 2007 17:44:54 -0500 Received: from mtagate6.uk.ibm.com ([195.212.29.139]:34521 "EHLO mtagate6.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053AbXBJWox (ORCPT ); Sat, 10 Feb 2007 17:44:53 -0500 Subject: Re: [patch 0/3] 2.6.20 fix for PageUptodate memorder problem (try 3) From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com To: Nick Piggin Cc: Andrew Morton , Hugh Dickins , Linux Memory Management , Linux Kernel In-Reply-To: <20070210001844.21921.48605.sendpatchset@linux.site> References: <20070210001844.21921.48605.sendpatchset@linux.site> Content-Type: text/plain Organization: IBM Corporation Date: Sat, 10 Feb 2007 23:44:55 +0100 Message-Id: <1171147495.31563.5.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2007-02-10 at 03:31 +0100, Nick Piggin wrote: > SetNewPageUptodate does not do the S390 page_test_and_clear_dirty, so > I'd like to make sure that's OK. An I/O operation on s390 will set the dirty bit for a page. That is the reason to have SetPageUptodate clear the per page dirty bit when the page is made uptodate the first time. Otherwise we end up writing each page back to its backing device at least once. If SetNewPageUptodate is used on new anonymous pages exclusively I don't see a problem in omitting the page_test_clear_dirty. -- blue skies, Martin. Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH "Reality continues to ruin my life." - Calvin.