Re: WARNINGs in set_task_reclaim_state with memory cgroup and full memory usage

[Michal Hocko]

On Tue 27-08-19 19:43:49, Yafang Shao wrote:
> On Tue, Aug 27, 2019 at 6:43 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> >
> > If there are no objection to the patch I will post it as a standalong
> > one.
> 
> I have no objection to your patch. It could fix the issue.
> 
> I still think that it is not proper to use a new scan_control here as
> it breaks the global reclaim context.
>
> This context switch from global reclaim to memcg reclaim is very
> subtle change to the subsequent processing, that may cause some
> unexpected behavior.

Why would it break it? Could you be more specific please?

> Anyway, we can send this patch as a standalong one.
> Feel free to add:
> 
> Acked-by: Yafang Shao <laoar.shao@xxxxxxxxx>

Thanks!
-- 
Michal Hocko
SUSE Labs