[PATCH RFC 07/29] mm/migrate: rename isolate_movable_page() to isolate_movable_ops_page()

[Matthew Wilcox]

On Wed, Jun 18, 2025 at 02:14:15PM -0400, Zi Yan wrote:
> On 18 Jun 2025, at 13:39, David Hildenbrand wrote:
> 
> > ... and start moving back to per-page things that will absolutely not be
> > folio things in the future. Add documentation and a comment that the
> > remaining folio stuff (lock, refcount) will have to be reworked as well.
> >
> > While at it, convert the VM_BUG_ON() into a WARN_ON_ONCE() and handle
> > it gracefully (relevant with further changes), and convert a
> > WARN_ON_ONCE() into a VM_WARN_ON_ONCE_PAGE().
> 
> The reason is that there is no upstream code, which use movable_ops for
> folios? Is there any fundamental reason preventing movable_ops from
> being used on folios?

folios either belong to a filesystem or they are anonymous memory, and
so either the filesystem knows how to migrate them (through its a_ops)
or the migration code knows how to handle anon folios directly.