Re: [Resend PATCH 1/6] mm/memcg: warning on !memcg after readahead page charged

Alex Shi
2020-08-25T01:25:01Z

reproduce using our linux-mm random bug collection on NUMA systems.
>>
>> OK, I must have missed that this was on ppc. The order makes more sense
>> now. I will have a look at this next week.
>
> OK, so I've had a look and I know what's going on there. The
> move_pages12 is migrating hugetlb pages. Those are not charged to any
> memcg. We have completely missed this case. There are two ways going
> around that. Drop the warning and update the comment so that we do not
> forget about that or special case hugetlb pages.
>
> I think the first option is better.
>

Hi Michal,

Compare to ignore the warning which is designed to give, seems addressing
the hugetlb out of charge issue is a better solution, otherwise the memcg
memory usage is out of control on hugetlb, is that right?

Thanks
Alex