Messages in this thread Patch in this message | | | 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 |
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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 <glommer@parallels.com> CC: Michal Hocko <mhocko@suse.cz> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Johannes Weiner <hannes@cmpxchg.org> CC: Mel Gorman <mgorman@suse.de> CC: Andrew Morton <akpm@linux-foundation.org> --- 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
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