From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753467AbZBJF4w (ORCPT ); Tue, 10 Feb 2009 00:56:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751202AbZBJF4o (ORCPT ); Tue, 10 Feb 2009 00:56:44 -0500 Received: from smtp103.mail.mud.yahoo.com ([209.191.85.213]:30412 "HELO smtp103.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750920AbZBJF4n (ORCPT ); Tue, 10 Feb 2009 00:56:43 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=QZELdwSGQz5AwVUv66zJlFx19YrOjxJDpMAANb2uivfu5erbvemC1/j9v+WNHIh8iDJ5/xlm8uHdRQrzzbgkIkdF+XnvJA/5GsAZ9pCoam2M6+Sd2Qs8hmPtYsBOXPGJIl45fkon/taRKA3u53jwKrb4l2IGLdjAmaBGWvUqifA= ; X-YMail-OSG: _EnS36sVM1kp.GPQufDtltHA2oX6I9OryZ.hDgy6ZJUGkOT6lZ_JEzPicH5eTeFqdtB48tdDnoozB3FgT.P.xgn3Y3J7efakcFpBiDPWxlVOkjToSvvNypHV7dTeKfDxpjwtTomSYEVs_1EOB166S8WOoojhVDSaOGW_8QfoclUKNvjPxl8hANvkDBwthA-- X-Yahoo-Newman-Property: ymail-3 From: Nick Piggin To: Linus Torvalds Subject: Re: [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O Date: Tue, 10 Feb 2009 16:56:13 +1100 User-Agent: KMail/1.9.51 (KDE/4.0.4; ; ) Cc: Mathieu Desnoyers , KOSAKI Motohiro , Jens Axboe , akpm@linux-foundation.org, Peter Zijlstra , Ingo Molnar , thomas.pi@arcor.dea, Yuriy Lalym , ltt-dev@lists.casi.polymtl.ca, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20090120122855.GF30821@kernel.dk> <20090210033652.GA28435@Krystal> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200902101656.13792.nickpiggin@yahoo.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 10 February 2009 16:23:56 Linus Torvalds wrote: > On Mon, 9 Feb 2009, Mathieu Desnoyers wrote: > > So this patch fixes this behavior by only decrementing the page > > accounting _after_ the block I/O writepage has been done. > > This makes no sense, really. > > Or rather, I don't mind the notion of updating the counters only after IO > per se, and _that_ part of it probably makes sense. But why is it that you > only then fix up two of the call-sites. There's a lot more call-sites than > that for this function. Well if you do that, then I'd think you also have to change some calculations that today use dirty+writeback. In some ways it does make sense, but OTOH it is natural in the pagecache since it was introduced to treat writeback as basically equivalent to dirty. So writeback && !dirty pages shouldn't cause things to blow up, or if it does then hopefully it is a simple bug somewhere. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id D7E1D6B003D for ; Tue, 10 Feb 2009 00:56:43 -0500 (EST) From: Nick Piggin Subject: Re: [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O Date: Tue, 10 Feb 2009 16:56:13 +1100 References: <20090120122855.GF30821@kernel.dk> <20090210033652.GA28435@Krystal> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200902101656.13792.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: Mathieu Desnoyers , KOSAKI Motohiro , Jens Axboe , akpm@linux-foundation.org, Peter Zijlstra , Ingo Molnar , thomas.pi@arcor.dea, Yuriy Lalym , ltt-dev@lists.casi.polymtl.ca, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Tuesday 10 February 2009 16:23:56 Linus Torvalds wrote: > On Mon, 9 Feb 2009, Mathieu Desnoyers wrote: > > So this patch fixes this behavior by only decrementing the page > > accounting _after_ the block I/O writepage has been done. > > This makes no sense, really. > > Or rather, I don't mind the notion of updating the counters only after IO > per se, and _that_ part of it probably makes sense. But why is it that you > only then fix up two of the call-sites. There's a lot more call-sites than > that for this function. Well if you do that, then I'd think you also have to change some calculations that today use dirty+writeback. In some ways it does make sense, but OTOH it is natural in the pagecache since it was introduced to treat writeback as basically equivalent to dirty. So writeback && !dirty pages shouldn't cause things to blow up, or if it does then hopefully it is a simple bug somewhere. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org