Okay, so after recent discussions, I am proposing the following patch. It won't remove hierarchy, or anything like that. Just default to true in the root cgroup, and print a warning once if you try to set it back to 0. I am not adding it to feature-removal-schedule.txt because I don't view it as a consensus. Rather, changing the default would allow us to give it a time around in the open, and see if people complain and what we can learn about that. Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx> CC: Michal Hocko <mhocko@xxxxxxx> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> CC: Johannes Weiner <hannes@xxxxxxxxxxx> CC: Tejun Heo <tj@xxxxxxxxxx> --- mm/memcontrol.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9e710bc..037ddd4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3949,6 +3949,8 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, if (memcg->use_hierarchy == val) goto out; + WARN_ONCE((!parent_memcg && memcg->use_hierarchy && val == false), + "Non-hierarchical memcg is considered for deprecation"); /* * If parent's use_hierarchy is set, we can't make any modifications * in the child subtrees. If it is unset, then the change can @@ -5175,6 +5177,7 @@ mem_cgroup_create(struct cgroup *cont) INIT_WORK(&stock->work, drain_local_stock); } hotcpu_notifier(memcg_cpu_hotplug_callback, 0); + memcg->use_hierarchy = true; } else { parent = mem_cgroup_from_cont(cont->parent); memcg->use_hierarchy = parent->use_hierarchy; -- 1.7.10.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>