Messages in this thread | | | From | Shakeel Butt <> | Date | Thu, 29 Oct 2020 08:48:45 -0700 | Subject | Re: [PATCH v2] mm: memcg/slab: Fix return child memcg objcg for root memcg |
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On Tue, Oct 27, 2020 at 8:50 PM Muchun Song <songmuchun@bytedance.com> wrote: > > Consider the following memcg hierarchy. > > root > / \ > A B > > If we get the objcg of memcg A failed,
Please fix the above statement.
> the get_obj_cgroup_from_current > can return the wrong objcg for the root memcg. > > Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > changelog in v2: > 1. Do not use a comparison with the root_mem_cgroup > > mm/memcontrol.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 1337775b04f3..8c8b4c3ed5a0 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2961,6 +2961,7 @@ __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) > objcg = rcu_dereference(memcg->objcg); > if (objcg && obj_cgroup_tryget(objcg)) > break; > + objcg = NULL;
Roman, in your cleanup, are you planning to have objcg for root memcg as well?
> } > rcu_read_unlock(); > > -- > 2.20.1 >
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