From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx140.postini.com [74.125.245.140]) by kanga.kvack.org (Postfix) with SMTP id C8C666B004A for ; Wed, 29 Feb 2012 14:43:11 -0500 (EST) Date: Wed, 29 Feb 2012 20:43:04 +0100 From: Johannes Weiner Subject: Re: [PATCH next] memcg: remove PCG_CACHE page_cgroup flag fix Message-ID: <20120229194304.GF1673@cmpxchg.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Andrew Morton , KAMEZAWA Hiroyuki , Konstantin Khlebnikov , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Tue, Feb 28, 2012 at 09:30:17PM -0800, Hugh Dickins wrote: > Swapping tmpfs loads show absurd wrapped rss and wrong cache in memcg's > memory.stat statistics: __mem_cgroup_uncharge_common() is failing to > distinguish the anon and tmpfs cases. > > Mostly we can decide between them by PageAnon, which is reliable once > it has been set; but there are several callers who need to uncharge a > MEM_CGROUP_CHARGE_TYPE_MAPPED page before it was fully initialized, > so allow that case to override the PageAnon decision. > > Signed-off-by: Hugh Dickins > --- > > mm/memcontrol.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > --- 3.3-rc5-next/mm/memcontrol.c 2012-02-25 10:06:52.496035568 -0800 > +++ linux/mm/memcontrol.c 2012-02-26 10:44:32.146365398 -0800 > @@ -2944,13 +2944,16 @@ __mem_cgroup_uncharge_common(struct page > if (!PageCgroupUsed(pc)) > goto unlock_out; > > + anon = PageAnon(page); > + > switch (ctype) { > case MEM_CGROUP_CHARGE_TYPE_MAPPED: > + anon = true; > + /* fallthrough */ If you don't mind, could you add a small comment on why this is the exception where we don't trust page->mapping? Other than that, Acked-by: Johannes Weiner > case MEM_CGROUP_CHARGE_TYPE_DROP: > /* See mem_cgroup_prepare_migration() */ > if (page_mapped(page) || PageCgroupMigration(pc)) > goto unlock_out; > - anon = true; > break; > case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: > if (!PageAnon(page)) { /* Shared memory */ > @@ -2958,10 +2961,8 @@ __mem_cgroup_uncharge_common(struct page > goto unlock_out; > } else if (page_mapped(page)) /* Anon */ > goto unlock_out; > - anon = true; > break; > default: > - anon = false; > break; > } -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org