From mboxrd@z Thu Jan 1 00:00:00 1970 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> References: <1373212616-11713-1-git-send-email-glommer@openvz.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=zZCIx9jtkjNGnxvKyEiGyi7s8MnFKfw+z+MYl7O6uc0=; b=vz1YR6yn+t+5tWFFQ/hgHCqGTRJDkwnMA4kvjENX7sL6MrwfMNbkXQKkwi+cnUe5fS yQqOV1DBHr08cXiqXR/aCqR7HeV6PnX1yoMxdNpcLAPYSJ+ptGteRSD+AjL7IHv0spHx tQWblfLu6M40GGtPP8F2jmETaDTRDZxPZMMyq1g27z6TJ0r9y1oQqNfxMhN80Z2yH3h5 qg2bdPuY+P/pGw+oWVmEx3mtzR9Tfhk84Tr2bB3cdBqO59YGN2okXP54X1qtw3SAQ/sU I3CKE4yMZKNFHbNhv80KEJ0XJ1aDuJNwhdKqtbVGVMktQfIV6Dx3dn15ehgX0Ups5/0O X/jg== In-Reply-To: <1373212616-11713-1-git-send-email-glommer@openvz.org> Sender: owner-linux-mm@kvack.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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