From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id E18F26B01F5 for ; Thu, 15 Apr 2010 02:35:18 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o3F6ZG2q032188 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Thu, 15 Apr 2010 15:35:16 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 0659A45DE4F for ; Thu, 15 Apr 2010 15:35:16 +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 D7BFA45DE55 for ; Thu, 15 Apr 2010 15:35:15 +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 BB3B81DB8041 for ; Thu, 15 Apr 2010 15:35:15 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 6B866E08003 for ; Thu, 15 Apr 2010 15:35:15 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH] mm: disallow direct reclaim page writeback In-Reply-To: <20100415062055.GQ2493@dastard> References: <20100415130212.D16E.A69D9226@jp.fujitsu.com> <20100415062055.GQ2493@dastard> Message-Id: <20100415152816.D18C.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Thu, 15 Apr 2010 15:35:14 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Dave Chinner Cc: kosaki.motohiro@jp.fujitsu.com, Mel Gorman , Chris Mason , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org List-ID: > On Thu, Apr 15, 2010 at 01:09:01PM +0900, KOSAKI Motohiro wrote: > > Hi > > > > > How about this? For now, we stop direct reclaim from doing writeback > > > only on order zero allocations, but allow it for higher order > > > allocations. That will prevent the majority of situations where > > > direct reclaim blows the stack and interferes with background > > > writeout, but won't cause lumpy reclaim to change behaviour. > > > This reduces the scope of impact and hence testing and validation > > > the needs to be done. > > > > Tend to agree. but I would proposed slightly different algorithm for > > avoind incorrect oom. > > > > for high order allocation > > allow to use lumpy reclaim and pageout() for both kswapd and direct reclaim > > SO same as current. Yes. as same as you propsed. > > > for low order allocation > > - kswapd: always delegate io to flusher thread > > - direct reclaim: delegate io to flusher thread only if vm pressure is low > > IMO, this really doesn't fix either of the problems - the bad IO > patterns nor the stack usage. All it will take is a bit more memory > pressure to trigger stack and IO problems, and the user reporting the > problems is generating an awful lot of memory pressure... This patch doesn't care stack usage. because - again, I think all stack eater shold be diet. - under allowing lumpy reclaim world, only deny low order reclaim doesn't solve anything. Please don't forget priority=0 recliam failure incvoke OOM-killer. I don't imagine anyone want it. And, Which IO workload trigger <6 priority vmscan? -- 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