From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753758Ab0LGVxp (ORCPT ); Tue, 7 Dec 2010 16:53:45 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:42590 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752189Ab0LGVxo (ORCPT ); Tue, 7 Dec 2010 16:53:44 -0500 Date: Tue, 7 Dec 2010 13:53:01 -0800 From: Andrew Morton To: Minchan Kim Cc: linux-mm , LKML , Balbir Singh , KAMEZAWA Hiroyuki , Mel Gorman Subject: Re: [PATCH] compaction: Remove mem_cgroup_del_lru Message-Id: <20101207135301.49898964.akpm@linux-foundation.org> In-Reply-To: <1291734086-1405-1-git-send-email-minchan.kim@gmail.com> References: <1291734086-1405-1-git-send-email-minchan.kim@gmail.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) 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 Wed, 8 Dec 2010 00:01:26 +0900 Minchan Kim wrote: > del_page_from_lru_list alreay called mem_cgroup_del_lru. > So we need to call it again. It makes wrong stat of memcg and > even happen VM_BUG_ON hit. > > Cc: Balbir Singh > Cc: KAMEZAWA Hiroyuki > Cc: Mel Gorman > Signed-off-by: Minchan Kim > --- > mm/compaction.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index 50b0a90..b0fbfdf 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -302,7 +302,6 @@ static unsigned long isolate_migratepages(struct zone *zone, > /* Successfully isolated */ > del_page_from_lru_list(zone, page, page_lru(page)); > list_add(&page->lru, migratelist); > - mem_cgroup_del_lru(page); > cc->nr_migratepages++; > nr_isolated++; > err, yes, that looks bad. This bug is present in 2.6.35 and 2.6.36 afaict, so I tagged the fix for -stable backporting.