Re: [PATCH memcg 0/1] false global OOM triggered by memcg-limited task

Vasily Averin
2021-10-18T19:18:53Z

On 18.10.2021 21:52, Vasily Averin wrote:
> On 18.10.2021 18:07, Shakeel Butt wrote:
>> On Mon, Oct 18, 2021 at 5:27 AM Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org> wrote:
>>>
>>> [restore the cc list]
>>>
>>> On Mon 18-10-21 15:14:26, Vasily Averin wrote:
>>>> On 18.10.2021 14:53, Michal Hocko wrote:
>>>>> On Mon 18-10-21 13:05:35, Vasily Averin wrote:
>>>>>> On 18.10.2021 12:04, Michal Hocko wrote:
>>>>>> Here we call try_charge_memcg() that return success and approve the allocation,
>>>>>> however then we hit into kmem limit and fail the allocation.
>>>>>
>>>>> Just to make sure I understand this would be for the v1 kmem explicit
>>>>> limit, correct?
>>>>
>>>> yes, I mean this limit.
>>>
>>> OK, thanks for the clarification. This is a known problem. Have a look
>>> at I think we consider that one to 0158115f702b ("memcg, kmem: deprecate
>>> kmem.limit_in_bytes"). We are reporting the deprecated and to-be removed
>>> status since 2019 without any actual report sugested by the kernel
>>> message. Maybe we should try and remove it and see whether that prompts
>>> some pushback.
>>>
>>
>> Yes, I think now should be the right time to take the next step for
>> deprecation of kmem limits:
>> https://lore.kernel.org/all/20201118175726.2453120-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org/
>
> Are you going to push it to stable kernels too?

Btw CONFIG_MEMCG_KMEM=y is set both in RHEL8 kernels and in ubuntu 20.04 LTS kernel 5.11.0-37.