From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx135.postini.com [74.125.245.135]) by kanga.kvack.org (Postfix) with SMTP id 5B95F6B005A for ; Tue, 17 Jul 2012 06:56:45 -0400 (EDT) Date: Tue, 17 Jul 2012 12:56:40 +0200 From: Michal Hocko Subject: Re: [PATCH] mm/memcg: remove redundant checking on root memcg Message-ID: <20120717105640.GB25435@tiehlicka.suse.cz> References: <1342518147-10406-1-git-send-email-liwanp@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1342518147-10406-1-git-send-email-liwanp@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wanpeng Li Cc: linux-mm@kvack.org, Johannes Weiner , KAMEZAWA Hiroyuki , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Gavin Shan On Tue 17-07-12 17:42:27, Wanpeng Li wrote: > Function __mem_cgroup_cancel_local_charge is only called by > mem_cgroup_move_parent. For this case, root memcg has been > checked by mem_cgroup_move_parent. So we needn't check that > again in function __mem_cgroup_cancel_local_charge and just > remove the check in function __mem_cgroup_cancel_local_charge. It's true that the check is not necessary but on the other hand __mem_cgroup_cancel_charge does check it and it would be unfortunate to have two very similar functions with different expectations (one can be called for the root cgroup while other one cannot). > Signed-off-by: Wanpeng Li > --- > mm/memcontrol.c | 3 --- > 1 files changed, 0 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 6392c0a..d346347 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2404,9 +2404,6 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, > { > unsigned long bytes = nr_pages * PAGE_SIZE; > > - if (mem_cgroup_is_root(memcg)) > - return; > - > res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes); > if (do_swap_account) > res_counter_uncharge_until(&memcg->memsw, > -- > 1.7.5.4 > > -- > To unsubscribe from this list: send the line "unsubscribe cgroups" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/ . Don't email: email@kvack.org