Re: [PATCH v4 1/2] mm: introduce process_mrelease system call

[Michal Hocko]

On Tue 03-08-21 15:09:43, Suren Baghdasaryan wrote:
> On Tue, Aug 3, 2021 at 10:27 AM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:
[...]
> > > > +     if (task_will_free_mem(task) && (task->flags & PF_KTHREAD) == 0) {
> > > > +             mm = task->mm;
> > > > +             mmget(mm);
> > > > +     }
> > > > +     task_unlock(task);
> > > > +     if (!mm) {
> > >
> > > Do we want to treat MMF_OOM_SKIP as a failure?
> >
> > Yeah, I don't think we want to create additional contention if
> > oom-killer is already working on this mm. Should we return EBUSY in
> > this case? Other possible options is ESRCH, indicating that this
> > process is a goner, so don't bother. WDYT?
> 
> After considering this some more I think ESRCH would be more
> appropriate. EBUSY might be understood as "I need to retry at a better
> time", which is not what we want here.

Why cannot we simply return 0 in that case. The work has been done
already by the kernel so why should we tell the caller that there was
something wrong?

-- 
Michal Hocko
SUSE Labs