From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx117.postini.com [74.125.245.117]) by kanga.kvack.org (Postfix) with SMTP id 861A96B005D for ; Tue, 25 Sep 2012 04:56:35 -0400 (EDT) From: Glauber Costa Subject: [RFC 4/4] memcg: do not walk all the way to the root for memcg Date: Tue, 25 Sep 2012 12:52:53 +0400 Message-Id: <1348563173-8952-5-git-send-email-glommer@parallels.com> In-Reply-To: <1348563173-8952-1-git-send-email-glommer@parallels.com> References: <1348563173-8952-1-git-send-email-glommer@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, devel@openvz.org, Peter Zijlstra , Glauber Costa , Michal Hocko , Kamezawa Hiroyuki , Johannes Weiner , Mel Gorman , Andrew Morton Since the root is special anyway, and we always get its figures from global counters anyway, there is no make all cgroups its descendants, wrt res_counters. The sad effect of doing that is that we need to lock the root for all allocations, since it is a common ancestor of everybody. Not having the root as a common ancestor should lead to better scalability for not-uncommon case of tasks in the cgroup being node-bound to different nodes in NUMA systems. Signed-off-by: Glauber Costa CC: Michal Hocko CC: Kamezawa Hiroyuki CC: Johannes Weiner CC: Mel Gorman CC: Andrew Morton --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f8115f0..829ea9e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5720,7 +5720,7 @@ mem_cgroup_create(struct cgroup *cont) static_key_slow_inc(&memcg_in_use_key); } - if (parent && parent->use_hierarchy) { + if (parent && !mem_cgroup_is_root(parent) && parent->use_hierarchy) { struct mem_cgroup __maybe_unused *p; res_counter_init(&memcg->res, &parent->res); -- 1.7.11.4 -- 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