On Fri, Dec 18, 2020 at 4:43 AM Michal Hocko <mhocko@xxxxxxxx> wrote: > > On Thu 17-12-20 13:52:38, Pavel Tatashin wrote: > > + * 1. Pinned pages: (long-term) pinning of movable pages is avoided > > + * when pages are pinned and faulted, but it is still possible that > > + * address space already has pages in ZONE_MOVABLE at the time when > > + * pages are pinned (i.e. user has touches that memory before > > + * pinning). In such case we try to migrate them to a different zone, > > + * but if migration fails the pages can still end-up pinned in > > + * ZONE_MOVABLE. In such case, memory offlining might retry a long > > + * time and will only succeed once user application unpins pages. > > I still dislike this. Pinning can fail so there shouldn't be any reasons > to break MOVABLE constrain for something that can be handled. If > anything there should be a very good reasoning behind this decision > documented. This is basically current behaviour, after patch 8, we can never pin pages in the movable zone, so I will update this comment in that patch. Thank you, Pasha > -- > Michal Hocko > SUSE Labs
