On Sun, Apr 03, 2022 at 02:08:33AM +0000, Wei Yang wrote: > After commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical > mode"), we won't have a NULL parent except root_mem_cgroup. And this > case is handled when (memcg == root). > > Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> > CC: Roman Gushchin <roman.gushchin@xxxxxxxxx> > CC: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>