Messages in this thread | | | From | Pavel Tatashin <> | Date | Mon, 23 Nov 2020 12:54:16 -0500 | Subject | Re: Pinning ZONE_MOVABLE pages |
| |
On Mon, Nov 23, 2020 at 12:15 PM Jason Gunthorpe <jgg@ziepe.ca> wrote: > > On Mon, Nov 23, 2020 at 11:06:21AM -0500, Pavel Tatashin wrote: > > > What I mean here is allowing users to guarantee that the page's PA is > > going to stay the same. Sort of a stronger mlock. Mlock only > > guarantees that the page is not swapped, but something like > > You've just described get/pin_user_pages(), that is exactly what it is > for.
You are right. No need for the madvise() flag at all. (The slight difference of being able to mark memory pinned prior to touching is really insignificant).
> > I agree with the other emails, ZONE_MOVABLE needs to be reconciled > with FOLL_LONGTERM - most likely by preventing ZONE_MOVABLE pages from > being returned. This will need migration like CMA does and the point > about faulting is only an optimization to prevent fault then immediate > migration.
That is right, as the first step we could just do fault and immediate migration, which is silly, but still better than what we have now.
> > Jason
| |