Re: [PATCH] mm/memcg: non-hierarchical mode is deprecated

[Wei Yang <richard.weiyang@xxxxxxxxx>]

On Mon, Apr 04, 2022 at 11:27:53AM +0200, Michal Hocko wrote:
>On Sun 03-04-22 02:08:33, 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>
>
>Acked-by: Michal Hocko <mhocko@xxxxxxxx>
>Thanks!
>

Thanks for the ack. When reading the code, I found one redundant check in
shrink_node_memcgs().

  shrink_node_memcgs
    mem_cgroup_below_min
      mem_cgroup_supports_protection
    mem_cgroup_below_low
      mem_cgroup_supports_protection

I am not sure it worthwhile to take it out.

  shrink_node_memcgs
    mem_cgroup_supports_protection
      mem_cgroup_below_min
      mem_cgroup_below_low

Look forward your opinion.

-- 
Wei Yang
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