Re: [PATCH v1 17/29] mm/page_isolation: drop __folio_test_movable() check for large folios

Harry Yoo
2025-07-02T09:56:18Z

On Tue, Jul 01, 2025 at 02:32:54PM +0200, David Hildenbrand wrote:
> On 01.07.25 13:03, Lorenzo Stoakes wrote:
> > On Mon, Jun 30, 2025 at 02:59:58PM +0200, David Hildenbrand wrote:
> > > Currently, we only support migration of individual movable_ops pages, so
> > > we can not run into that.
> > >
> > > Reviewed-by: Zi Yan <ziy@nvidia.com>
> > > Signed-off-by: David Hildenbrand <david@redhat.com>
> >
> > Seems sensible, so:
> >
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> >
> > Maybe worth adding a VM_WARN_ON_ONCE() just in case? Or do you think not worth it?
>
> Not for now I think. Whoever wants to support compound pages has to fixup a
> bunch of other stuff first, before running into that one here.
>
> So a full audit of all paths that handle page_has_movable_ops() is required
> either way.

IIRC there was an RFC series last year [1] that adds support for
order > 0 pages in zsmalloc.

Cc'ing Barry and Tangquan in case it's still on their TODO list...

[1] https://lore.kernel.org/linux-mm/20241121222521.83458-2-21cnbao@gmail.com

--
Cheers,
Harry / Hyeonggon