From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx189.postini.com [74.125.245.189]) by kanga.kvack.org (Postfix) with SMTP id 11B9C6B0306 for ; Mon, 25 Jun 2012 14:34:47 -0400 (EDT) Received: by pbbrp2 with SMTP id rp2so8607086pbb.14 for ; Mon, 25 Jun 2012 11:34:47 -0700 (PDT) Date: Mon, 25 Jun 2012 11:34:42 -0700 From: Tejun Heo Subject: Re: [PATCH 10/11] memcg: allow a memcg with kmem charges to be destructed. Message-ID: <20120625183442.GG3869@google.com> References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-11-git-send-email-glommer@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1340633728-12785-11-git-send-email-glommer@parallels.com> 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, kamezawa.hiroyu@jp.fujitsu.com, Pekka Enberg , Suleiman Souhlal On Mon, Jun 25, 2012 at 06:15:27PM +0400, 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); WARN_ON() please. Misaccounted kernel usually is better than dead kernel. Thanks. -- tejun -- 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