Messages in this thread | | | Date | Wed, 19 Sep 2012 12:38:18 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH 2.6.32] memcg: warn on deeper hierarchies with use_hierarchy==0 |
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On Wed, 19 Sep 2012, Michal Hocko wrote:
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index f99f599..b61c34b 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3106,6 +3106,11 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) > } else { > parent = mem_cgroup_from_cont(cont->parent); > mem->use_hierarchy = parent->use_hierarchy; > + WARN_ONCE(!mem->use_hierarchy && parent != root_mem_cgroup, > + "Creating hierarchies with use_hierarchy==0 " > + "(flat hierarchy) is considered deprecated. " > + "If you believe that your setup is correct, " > + "we kindly ask you to contact linux-mm@kvack.org and let us know");
When I deprecated /proc/pid/oom_adj (now removed), we did a WARN_ONCE() and others complained that this unnecessarily alters userspace scripts that a serious issue has occurred and Linus agreed that we shouldn't do deprecation in this way. The alternative is to use printk_once() instead.
This applies to all three patches for this one, 3.0, and 3.2+.
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