Re: [PATCH] mm/memcontrol: stop resize loop if limit was changed again

[Michal Hocko]

On Wed 20-03-24 13:09:07, Waiman Long wrote:
> 
> On 3/20/24 06:03, Pavel Tikhomirov wrote:
> > In memory_max_write() we first set memcg->memory.max and only then
> > try to enforce it in loop. What if while we are in loop someone else
> > have changed memcg->memory.max but we are still trying to enforce
> > the old value? I believe this can lead to nasty consequence like getting
> > an oom on perfectly fine cgroup within it's limits or excess reclaim.
> 
> Concurrent write to the same cgroup control file is not possible as the
> underlying kernfs_open_file structure has a mutex that serialize access to
> the file.

This is good to know and I was not aware of that. Thanks!
-- 
Michal Hocko
SUSE Labs