Re: [PATCH] mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified

[Andrew Morton]

On Wed, 27 Sep 2023 14:39:21 -0700 Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:

> > >
> > >> The code should conceptually do:
> > >>
> > >>   if (MPOL_MF_MOVE|MOVEALL)
> > >>       scan all vmas
> > >>       try to migrate the existing pages
> > >>       return success
> > >>   else if (MPOL_MF_MOVE* | MPOL_MF_STRICT)
> > >>       scan all vmas
> > >>       try to migrate the existing pages
> > >>       return -EIO if unmovable or migration failed
> > >>   else /* MPOL_MF_STRICT alone */
> > >>       break early if meets unmovable and don't call mbind_range() at all
> > >>   else /* none of those flags */
> > >>       check the ranges in test_walk, EFAULT without mbind_range() if discontig.
> 
> With this change I think my temporary fix at
> https://lore.kernel.org/all/20230918211608.3580629-1-surenb@xxxxxxxxxx/
> can be removed because we either scan all vmas (which means we locked
> them all) or we break early and do not call mbind_range() at all (in
> which case we don't need vmas to be locked).

Thanks, I dropped "mm: lock VMAs skipped by a failed queue_pages_range()"