From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755911Ab1KXKeS (ORCPT ); Thu, 24 Nov 2011 05:34:18 -0500 Received: from cantor2.suse.de ([195.135.220.15]:44634 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752002Ab1KXKeO (ORCPT ); Thu, 24 Nov 2011 05:34:14 -0500 Date: Thu, 24 Nov 2011 11:34:12 +0100 From: Michal Hocko To: Johannes Weiner Cc: KAMEZAWA Hiroyuki , Andrew Morton , Balbir Singh , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch 6/8] mm: memcg: remove unneeded checks from uncharge_page() Message-ID: <20111124103411.GH26036@tiehlicka.suse.cz> References: <1322062951-1756-1-git-send-email-hannes@cmpxchg.org> <1322062951-1756-7-git-send-email-hannes@cmpxchg.org> <20111124090619.895988e7.kamezawa.hiroyu@jp.fujitsu.com> <20111124090639.GD6843@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111124090639.GD6843@cmpxchg.org> 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 On Thu 24-11-11 10:06:39, Johannes Weiner wrote: > On Thu, Nov 24, 2011 at 09:06:19AM +0900, KAMEZAWA Hiroyuki wrote: > > On Wed, 23 Nov 2011 16:42:29 +0100 > > Johannes Weiner wrote: > > > > > From: Johannes Weiner > > > > > > mem_cgroup_uncharge_page() is only called on either freshly allocated > > > pages without page->mapping or on rmapped PageAnon() pages. There is > > > no need to check for a page->mapping that is not an anon_vma. > > > > > > Signed-off-by: Johannes Weiner > > > > For making our assumption clearer to readers of codes, > > VM_BUG_ON(page->mapping && !PageAnon(page)) please. > > Yep, delta patch below. > > > Anyway, > > Acked-by: KAMEZAWA Hiroyuki > > Thanks! > > --- > From: Johannes Weiner > Subject: mm: memcg: remove unneeded checks from uncharge_page() fix > > Document page state assumptions and catch if they are violated in > uncharge_page(). > > Signed-off-by: Johannes Weiner Same here Acked-by: Michal Hocko > --- > mm/memcontrol.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 2f1fdc4..872dae1 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2992,6 +2992,7 @@ void mem_cgroup_uncharge_page(struct page *page) > /* early check. */ > if (page_mapped(page)) > return; > + VM_BUG_ON(page->mapping && !PageAnon(page)); > __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); > } > > -- > 1.7.6.4 > -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic