From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx132.postini.com [74.125.245.132]) by kanga.kvack.org (Postfix) with SMTP id 3B9946B0037 for ; Sun, 7 Jul 2013 11:57:12 -0400 (EDT) Received: by mail-la0-f41.google.com with SMTP id fn20so3193210lab.28 for ; Sun, 07 Jul 2013 08:57:10 -0700 (PDT) From: Glauber Costa Subject: [PATCH v10 01/16] memcg: make cache index determination more robust Date: Sun, 7 Jul 2013 11:56:41 -0400 Message-Id: <1373212616-11713-2-git-send-email-glommer@openvz.org> In-Reply-To: <1373212616-11713-1-git-send-email-glommer@openvz.org> References: <1373212616-11713-1-git-send-email-glommer@openvz.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org, mgorman@suse.de, david@fromorbit.com, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suze.cz, hannes@cmpxchg.org, hughd@google.com, gthelen@google.com, akpm@linux-foundation.org, Glauber Costa , Glauber Costa , Michal Hocko From: Glauber Costa I caught myself doing something like the following outside memcg core: memcg_id = -1; if (memcg && memcg_kmem_is_active(memcg)) memcg_id = memcg_cache_id(memcg); to be able to handle all possible memcgs in a sane manner. In particular, the root cache will have kmemcg_id = -1 (just because we don't call memcg_kmem_init to the root cache since it is not limitable). We have always coped with that by making sure we sanitize which cache is passed to memcg_cache_id. Although this example is given for root, what we really need to know is whether or not a cache is kmem active. But outside the memcg core testing for root, for instance, is not trivial since we don't export mem_cgroup_is_root. I ended up realizing that this tests really belong inside memcg_cache_id. This patch moves a similar but stronger test inside memcg_cache_id and make sure it always return a meaningful value. Signed-off-by: Glauber Costa Cc: Johannes Weiner Cc: Michal Hocko Cc: Kamezawa Hiroyuki --- mm/memcontrol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6e120e4..506ad46 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3061,7 +3061,9 @@ void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep) */ int memcg_cache_id(struct mem_cgroup *memcg) { - return memcg ? memcg->kmemcg_id : -1; + if (!memcg || !memcg_can_account_kmem(memcg)) + return -1; + return memcg->kmemcg_id; } /* -- 1.8.2.1 -- 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