From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754797Ab0FPBpN (ORCPT ); Tue, 15 Jun 2010 21:45:13 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:38505 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754286Ab0FPBpJ (ORCPT ); Tue, 15 Jun 2010 21:45:09 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Wed, 16 Jun 2010 10:40:36 +0900 From: KAMEZAWA Hiroyuki To: Rik van Riel Cc: Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Johannes Weiner , Christoph Hellwig , Andrew Morton Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim Message-Id: <20100616104036.b45d352b.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <4C182097.2070603@redhat.com> References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-13-git-send-email-mel@csn.ul.ie> <4C16A567.4080000@redhat.com> <20100615114510.GE26788@csn.ul.ie> <4C17815A.8080402@redhat.com> <20100615135928.GK26788@csn.ul.ie> <4C178868.2010002@redhat.com> <20100615141601.GL26788@csn.ul.ie> <20100616091755.7121c7d3.kamezawa.hiroyu@jp.fujitsu.com> <4C181AFD.5060503@redhat.com> <20100616093958.00673123.kamezawa.hiroyu@jp.fujitsu.com> <4C182097.2070603@redhat.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.2 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 15 Jun 2010 20:53:43 -0400 Rik van Riel wrote: > On 06/15/2010 08:39 PM, KAMEZAWA Hiroyuki wrote: > > > Hmm, or do you recommend no-dirty-page-writeback when a memcg hits limit ? > > Maybe we'll see much swaps. > > > > I want to go with this for a while, changing memcg's behavior will took > > some amounts of time, there are only a few developpers. > > One thing we can do, for kswapd, memcg and direct reclaim alike, > is to tell the flusher threads to flush pages related to a pageout > candidate page to disk. > > That way the reclaiming processes can wait on some disk IO to > finish, while the flusher thread takes care of the actual flushing. > > That should also fix the "kswapd filesystem IO has really poor IO > patterns" issue. > > There's no reason not to fix this issue the right way. > yes. but this patch just stops writeback. I think it's sane to ask not to change behavior until there are some useful changes in flusher threads. IMO, until flusher threads can work with I/O cgroup, memcg shoudln't depend on it because writeback allows stealing resource without it. Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 690816B01C7 for ; Tue, 15 Jun 2010 21:50:16 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o5G1j3e8009050 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Wed, 16 Jun 2010 10:45:04 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id B7B5945DE55 for ; Wed, 16 Jun 2010 10:45:03 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 929C245DE51 for ; Wed, 16 Jun 2010 10:45:03 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 749171DB803E for ; Wed, 16 Jun 2010 10:45:03 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 028A31DB803B for ; Wed, 16 Jun 2010 10:45:03 +0900 (JST) Date: Wed, 16 Jun 2010 10:40:36 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim Message-Id: <20100616104036.b45d352b.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <4C182097.2070603@redhat.com> References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-13-git-send-email-mel@csn.ul.ie> <4C16A567.4080000@redhat.com> <20100615114510.GE26788@csn.ul.ie> <4C17815A.8080402@redhat.com> <20100615135928.GK26788@csn.ul.ie> <4C178868.2010002@redhat.com> <20100615141601.GL26788@csn.ul.ie> <20100616091755.7121c7d3.kamezawa.hiroyu@jp.fujitsu.com> <4C181AFD.5060503@redhat.com> <20100616093958.00673123.kamezawa.hiroyu@jp.fujitsu.com> <4C182097.2070603@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Johannes Weiner , Christoph Hellwig , Andrew Morton List-ID: On Tue, 15 Jun 2010 20:53:43 -0400 Rik van Riel wrote: > On 06/15/2010 08:39 PM, KAMEZAWA Hiroyuki wrote: > > > Hmm, or do you recommend no-dirty-page-writeback when a memcg hits limit ? > > Maybe we'll see much swaps. > > > > I want to go with this for a while, changing memcg's behavior will took > > some amounts of time, there are only a few developpers. > > One thing we can do, for kswapd, memcg and direct reclaim alike, > is to tell the flusher threads to flush pages related to a pageout > candidate page to disk. > > That way the reclaiming processes can wait on some disk IO to > finish, while the flusher thread takes care of the actual flushing. > > That should also fix the "kswapd filesystem IO has really poor IO > patterns" issue. > > There's no reason not to fix this issue the right way. > yes. but this patch just stops writeback. I think it's sane to ask not to change behavior until there are some useful changes in flusher threads. IMO, until flusher threads can work with I/O cgroup, memcg shoudln't depend on it because writeback allows stealing resource without it. Thanks, -Kame -- 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