Hi Jonathan,
On Mon, Dec 18, 2023 at 06:33:44PM +0000, Cavitt, Jonathan wrote:
...
> > On Tue, Nov 28, 2023 at 08:25:05AM -0800, Jonathan Cavitt wrote:
> > > Never block for outstanding work on userptr object upon receipt of a
> > > mmu-notifier. The reason we originally did so was to immediately unbind
> > > the userptr and unpin its pages, but since that has been dropped in
> > > commit b4b9731b02c3c ("drm/i915: Simplify userptr locking"), we never
> > > return the pages to the system i.e. never drop our page->mapcount and so
> > > do not allow the page and CPU PTE to be revoked. Based on this history,
> > > we know we are safe to drop the wait entirely.
> > >
> > > Upon return from mmu-notifier, we will still have the userptr pages
> > > pinned preventing the following PTE operation (such as try_to_unmap)
> > > adjusting the vm_area_struct, so it is safe to keep the pages around for
> > > as long as we still have i/o pending.
> > >
> > > We do not have any means currently to asynchronously revalidate the
> > > userptr pages, that is always prior to next use.
> > >
> > > Signed-off-by: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Jonathan Cavitt <jonathan.cavitt@xxxxxxxxx>
> >
> > Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
>
> Thank you for the review! I don't think I have permission to push this upstream,
> though, so you or someone else will have to complete the push.
pushed in drm-intel-gt-next.
Thanks and sorry for the late merge.
Andi
