From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx116.postini.com [74.125.245.116]) by kanga.kvack.org (Postfix) with SMTP id C45416B012F for ; Tue, 26 Jun 2012 02:02:15 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 4B42F3EE0C0 for ; Tue, 26 Jun 2012 15:02:14 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 30C0645DE55 for ; Tue, 26 Jun 2012 15:02:14 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id F09CB45DE51 for ; Tue, 26 Jun 2012 15:02:13 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id DE0A7E08003 for ; Tue, 26 Jun 2012 15:02:13 +0900 (JST) Received: from m1001.s.css.fujitsu.com (m1001.s.css.fujitsu.com [10.240.81.139]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 912021DB8037 for ; Tue, 26 Jun 2012 15:02:13 +0900 (JST) Message-ID: <4FE94FDC.7070105@jp.fujitsu.com> Date: Tue, 26 Jun 2012 14:59:56 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH 10/11] memcg: allow a memcg with kmem charges to be destructed. References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-11-git-send-email-glommer@parallels.com> In-Reply-To: <1340633728-12785-11-git-send-email-glommer@parallels.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, Frederic Weisbecker , David Rientjes , Pekka Enberg , Michal Hocko , Johannes Weiner , Christoph Lameter , devel@openvz.org, Tejun Heo , Pekka Enberg , Suleiman Souhlal (2012/06/25 23:15), Glauber Costa wrote: > Because the ultimate goal of the kmem tracking in memcg is to > track slab pages as well, we can't guarantee that we'll always > be able to point a page to a particular process, and migrate > the charges along with it - since in the common case, a page > will contain data belonging to multiple processes. > > Because of that, when we destroy a memcg, we only make sure > the destruction will succeed by discounting the kmem charges > from the user charges when we try to empty the cgroup. > > Signed-off-by: Glauber Costa > CC: Christoph Lameter > CC: Pekka Enberg > CC: Michal Hocko > CC: Kamezawa Hiroyuki > CC: Johannes Weiner > CC: Suleiman Souhlal > --- > mm/memcontrol.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a6a440b..bb9b6fe 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -598,6 +598,11 @@ static void disarm_kmem_keys(struct mem_cgroup *memcg) > { > if (test_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted)) > static_key_slow_dec(&mem_cgroup_kmem_enabled_key); > + /* > + * This check can't live in kmem destruction function, > + * since the charges will outlive the cgroup > + */ > + BUG_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0); > } > #else > static void disarm_kmem_keys(struct mem_cgroup *memcg) > @@ -3838,6 +3843,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all) > int node, zid, shrink; > int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; > struct cgroup *cgrp = memcg->css.cgroup; > + u64 usage; > > css_get(&memcg->css); > > @@ -3877,8 +3883,10 @@ move_account: > if (ret == -ENOMEM) > goto try_to_free; > cond_resched(); > + usage = res_counter_read_u64(&memcg->res, RES_USAGE) - > + res_counter_read_u64(&memcg->kmem, RES_USAGE); > /* "ret" should also be checked to ensure all lists are empty. */ > - } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret); > + } while (usage > 0 || ret); > out: > css_put(&memcg->css); > return ret; > Hm....maybe work enough. Could you add more comments on the code ? Acked-by: KAMEZAWA Hiroyuki -- 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