From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id m933fjN8030169 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Fri, 3 Oct 2008 12:41:45 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 6CA8C2AC026 for ; Fri, 3 Oct 2008 12:41:45 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 453DA12C045 for ; Fri, 3 Oct 2008 12:41:45 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 290551DB803A for ; Fri, 3 Oct 2008 12:41:45 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id D288A1DB803B for ; Fri, 3 Oct 2008 12:41:41 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 4/4] capture pages freed during direct reclaim for allocation by the reclaimer In-Reply-To: <48E4F6EC.7010500@linux-foundation.org> References: <20081002143508.GE11089@brain> <48E4F6EC.7010500@linux-foundation.org> Message-Id: <20081003123545.EF5B.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 3 Oct 2008 12:41:41 +0900 (JST) Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: kosaki.motohiro@jp.fujitsu.com, Andy Whitcroft , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Rik van Riel , Mel Gorman , Nick Piggin , Andrew Morton List-ID: Hi Cristoph, > >> At the beginning of reclaim just flush all pcp pages and then do not allow pcp > >> refills again until reclaim is finished? > > > > Not entirely, some pages could get trapped there for sure. But it is > > parallel allocations we are trying to guard against. Plus we already flush > > the pcp during reclaim for higher orders. > > So we just would need to forbid refilling the pcp. > > Parallel allocations are less a problem if the freed order 0 pages get merged > immediately into the order 1 freelist. Of course that will only work 50% of > the time but it will have a similar effect to this patch. Ah, Right. Could we hear why you like pcp disabling than Andy's patch? Honestly, I think pcp has some problem. But I avoid to change pcp because I don't understand its design. Maybe, we should discuss currect pcp behavior? -- 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