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 <[email protected]> CC: Michal Hocko <[email protected]> CC: Kamezawa Hiroyuki <[email protected]> CC: Johannes Weiner <[email protected]> CC: Mel Gorman <[email protected]> CC: Andrew Morton <[email protected]> --- 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
