Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758981Ab1FWJCL (ORCPT ); Thu, 23 Jun 2011 05:02:11 -0400 Received: from cantor2.suse.de ([195.135.220.15]:55529 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755076Ab1FWJCJ (ORCPT ); Thu, 23 Jun 2011 05:02:09 -0400 Date: Thu, 23 Jun 2011 11:02:04 +0200 From: Michal Hocko To: KAMEZAWA Hiroyuki Cc: Christoph Hellwig , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Hugh Dickins , Rik van Riel , Michel Lespinasse , Mel Gorman , Lutz Vieweg Subject: Re: [PATCH] memcg: unlock page before charging it. (WasRe: [PATCH V2] mm: Do not keep page locked during page fault while charging it for memcg Message-ID: <20110623090204.GE31593@tiehlicka.suse.cz> References: <20110622120635.GB14343@tiehlicka.suse.cz> <20110622121516.GA28359@infradead.org> <20110622123204.GC14343@tiehlicka.suse.cz> <20110623150842.d13492cd.kamezawa.hiroyu@jp.fujitsu.com> <20110623074133.GA31593@tiehlicka.suse.cz> <20110623170811.16f4435f.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110623170811.16f4435f.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 976 Lines: 31 On Thu 23-06-11 17:08:11, KAMEZAWA Hiroyuki wrote: > On Thu, 23 Jun 2011 09:41:33 +0200 > Michal Hocko wrote: [...] > > Other than that: > > Reviewed-by: Michal Hocko > > > > I found the page is added to LRU before charging. (In this case, > memcg's LRU is ignored.) I'll post a new version with a fix. Yes, you are right. I have missed that. This means that we might race with reclaim which could evict the COWed page wich in turn would uncharge that page even though we haven't charged it yet. Can we postpone page_add_new_anon_rmap to the charging path or it would just race somewhere else? -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/