From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752171AbaBJO3P (ORCPT ); Mon, 10 Feb 2014 09:29:15 -0500 Received: from mail-wg0-f42.google.com ([74.125.82.42]:41844 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751919AbaBJO3O (ORCPT ); Mon, 10 Feb 2014 09:29:14 -0500 Date: Mon, 10 Feb 2014 15:29:11 +0100 From: Michal Hocko To: Johannes Weiner Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch 5/8] memcg: remove unnecessary !mm check from try_get_mem_cgroup_from_mm() Message-ID: <20140210142911.GJ7117@dhcp22.suse.cz> References: <1391792665-21678-1-git-send-email-hannes@cmpxchg.org> <1391792665-21678-6-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1391792665-21678-6-git-send-email-hannes@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 Fri 07-02-14 12:04:22, Johannes Weiner wrote: > Users pass either a mm that has been established under task lock, or > use a verified current->mm, which means the task can't be exiting. > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/memcontrol.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index e1d7f33227e4..689fffdee471 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1075,13 +1075,6 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) > { > struct mem_cgroup *memcg = NULL; > > - if (!mm) > - return NULL; > - /* > - * Because we have no locks, mm->owner's may be being moved to other > - * cgroup. We use css_tryget() here even if this looks > - * pessimistic (rather than adding locks here). > - */ > rcu_read_lock(); > do { > memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); > -- > 1.8.5.3 > -- Michal Hocko SUSE Labs