From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761342Ab2CNRx7 (ORCPT ); Wed, 14 Mar 2012 13:53:59 -0400 Received: from cantor2.suse.de ([195.135.220.15]:51063 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761104Ab2CNRx6 (ORCPT ); Wed, 14 Mar 2012 13:53:58 -0400 Date: Wed, 14 Mar 2012 18:53:55 +0100 From: Michal Hocko To: Johannes Weiner Cc: Konstantin Khlebnikov , KAMEZAWA Hiroyuki , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch 2/2] mm: memcg: count pte references from every member of the reclaimed hierarchy Message-ID: <20120314175355.GI4434@tiehlicka.suse.cz> References: <1330438489-21909-1-git-send-email-hannes@cmpxchg.org> <1330438489-21909-2-git-send-email-hannes@cmpxchg.org> <20120314142519.GF4434@tiehlicka.suse.cz> <20120314162129.GA1709@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120314162129.GA1709@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 Wed 14-03-12 17:21:29, Johannes Weiner wrote: > On Wed, Mar 14, 2012 at 03:25:19PM +0100, Michal Hocko wrote: > > On Tue 28-02-12 15:14:49, Johannes Weiner wrote: > > [...] > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > index b4622fb..21004df 100644 > > > --- a/mm/memcontrol.c > > > +++ b/mm/memcontrol.c > > > @@ -1044,17 +1044,23 @@ struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone, > > > * Checks whether given mem is same or in the root_mem_cgroup's > > > * hierarchy subtree > > > */ > > > -static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, > > > - struct mem_cgroup *memcg) > > > +bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, > > > + struct mem_cgroup *memcg) > > > { > > > - bool ret; > > > - > > > if (root_memcg == memcg) > > > return true; > > > if (!root_memcg->use_hierarchy) > > > return false; > > > + return css_is_ancestor(&memcg->css, &root_memcg->css); > > > +} > > > + > > > +static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, > > > + struct mem_cgroup *memcg) > > > +{ > > > + bool ret; > > > + > > > rcu_read_lock(); > > > - ret = css_is_ancestor(&memcg->css, &root_memcg->css); > > > + ret = __mem_cgroup_same_or_subtree(root_memcg, memcg); > > > rcu_read_unlock(); > > > return ret; > > > } > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > index c631234..120646e 100644 > > > --- a/mm/vmscan.c > > > +++ b/mm/vmscan.c > > > @@ -708,7 +708,8 @@ static enum page_references page_check_references(struct page *page, > > > int referenced_ptes, referenced_page; > > > unsigned long vm_flags; > > > > > > - referenced_ptes = page_referenced(page, 1, mz->mem_cgroup, &vm_flags); > > > + referenced_ptes = page_referenced(page, 1, sc->target_mem_cgroup, > > > + &vm_flags); > > > referenced_page = TestClearPageReferenced(page); > > > > Maybe a stupid question but isn't target_mem_cgroup NULL in the global > > reclaim case? And we doesn't handle that in __mem_cgroup_same_or_subtree... > > It's intentional, page_referenced() does not call into same_or_subtree > if the group is NULL. As a result, no references are filtered, they > all matter in the global reclaim case. You are right of course. Sorry I am probably still in the vacation mode... -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic