Re: [PATCH 0/2] mm: skip memcg for certain address space

Michal Hocko
2024-07-18T07:25:48Z

On Thu 18-07-24 09:17:42, Vlastimil Babka (SUSE) wrote:
> On 7/18/24 12:38 AM, Qu Wenruo wrote:
[...]
> > Does the folio order has anything related to the problem or just a
> > higher order makes it more possible?
>
> I didn't spot anything in the memcg charge path that would depend on the
> order directly, hm. Also what kernel version was showing these soft lockups?

Correct. Order just defines the number of charges to be reclaimed.
Unlike the page allocator path we do not have any specific requirements
on the memory to be released.

> > And finally, even without the hang problem, does it make any sense to
> > skip all the possible memcg charge completely, either to reduce latency
> > or just to reduce GFP_NOFAIL usage, for those user inaccessible inodes?

Let me just add to the pile of questions. Who does own this memory?

--
Michal Hocko
SUSE Labs