On Thu, May 7, 2020 at 9:47 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote:
>
> On Thu 07-05-20 09:33:01, Shakeel Butt wrote:
> [...]
> > @@ -2600,8 +2596,23 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
> > schedule_work(&memcg->high_work);
> > break;
> > }
> > - current->memcg_nr_pages_over_high += batch;
> > - set_notify_resume(current);
> > +
> > + if (gfpflags_allow_blocking(gfp_mask))
> > + reclaim_over_high(memcg, gfp_mask, batch);
> > +
> > + if (page_counter_read(&memcg->memory) <=
> > + READ_ONCE(memcg->high))
> > + break;
>
> I am half way to a long weekend so bear with me. Shouldn't this be continue? The
> parent memcg might be still in excess even the child got reclaimed,
> right?
>
The reclaim_high() actually already does this walk up to the root and
reclaim from ones who are still over their high limit. Though having
'continue' here is correct too.
> > + /*
> > + * The above reclaim might not be able to do much. Punt
> > + * the high reclaim to return to userland if the current
> > + * task shares the hierarchy.
> > + */
> > + if (current->mm && mm_match_cgroup(current->mm, memcg)) {
> > + current->memcg_nr_pages_over_high += batch;
> > + set_notify_resume(current);
> > + } else
> > + schedule_work(&memcg->high_work);
> > break;
> > }
> > } while ((memcg = parent_mem_cgroup(memcg)));
> > --
> > 2.26.2.526.g744177e7f7-goog
> >
>
> --
> Michal Hocko
> SUSE Labs
