Based on mm/mm-new.

In the future, as we decouple "struct page" from "struct folio", pages
that support "non-lru page migration" -- movable_ops page migration
such as memory balloons and zsmalloc -- will no longer be folios. They
will not have ->mapping, ->lru, and likely no refcount and no
page lock. But they will have a type and flags :)

This is the first part (other parts not written yet) of decoupling
movable_ops page migration from folio migration.

In this series, we get rid of the ->mapping usage, and start cleaning up
the code + separating it from folio migration.

Migration core will have to be further reworked to not treat movable_ops
pages like folios. This is the first step into that direction.

Heavily tested with virtio-balloon and lightly tested with zsmalloc
on x86-64. Cross-compile-tested.

RFC -> v1:
* Some smaller fixups + comment changes + subject/description updates
* Added ACKs/RBs (hope I didn't miss any)
* "mm/migrate: move movable_ops page handling out of move_to_new_folio()"
 -> Fix goto out; vs goto out_unlock_both;
* "mm: remove __folio_test_movable()"
 -> Fix page_has_movable_ops() checking wrong page

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Xu Xin <xu.xin16@zte.com.cn>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>


David Hildenbrand (29):
  mm/balloon_compaction: we cannot have isolated pages in the balloon
    list
  mm/balloon_compaction: convert balloon_page_delete() to
    balloon_page_finalize()
  mm/zsmalloc: drop PageIsolated() related VM_BUG_ONs
  mm/page_alloc: let page freeing clear any set page type
  mm/balloon_compaction: make PageOffline sticky until the page is freed
  mm/zsmalloc: make PageZsmalloc() sticky until the page is freed
  mm/migrate: rename isolate_movable_page() to
    isolate_movable_ops_page()
  mm/migrate: rename putback_movable_folio() to
    putback_movable_ops_page()
  mm/migrate: factor out movable_ops page handling into
    migrate_movable_ops_page()
  mm/migrate: remove folio_test_movable() and folio_movable_ops()
  mm/migrate: move movable_ops page handling out of move_to_new_folio()
  mm/zsmalloc: stop using __ClearPageMovable()
  mm/balloon_compaction: stop using __ClearPageMovable()
  mm/migrate: remove __ClearPageMovable()
  mm/migration: remove PageMovable()
  mm: rename __PageMovable() to page_has_movable_ops()
  mm/page_isolation: drop __folio_test_movable() check for large folios
  mm: remove __folio_test_movable()
  mm: stop storing migration_ops in page->mapping
  mm: convert "movable" flag in page->mapping to a page flag
  mm: rename PG_isolated to PG_movable_ops_isolated
  mm/page-flags: rename PAGE_MAPPING_MOVABLE to PAGE_MAPPING_ANON_KSM
  mm/page-alloc: remove PageMappingFlags()
  mm/page-flags: remove folio_mapping_flags()
  mm: simplify folio_expected_ref_count()
  mm: rename PAGE_MAPPING_* to FOLIO_MAPPING_*
  docs/mm: convert from "Non-LRU page migration" to "movable_ops page
    migration"
  mm/balloon_compaction: "movable_ops" doc updates
  mm/balloon_compaction: provide single balloon_page_insert() and
    balloon_mapping_gfp_mask()

 Documentation/mm/page_migration.rst  |  39 ++--
 arch/powerpc/platforms/pseries/cmm.c |   2 +-
 drivers/misc/vmw_balloon.c           |   3 +-
 drivers/virtio/virtio_balloon.c      |   4 +-
 fs/proc/page.c                       |   4 +-
 include/linux/balloon_compaction.h   |  90 ++++-----
 include/linux/fs.h                   |   2 +-
 include/linux/migrate.h              |  46 +----
 include/linux/mm.h                   |   4 +-
 include/linux/mm_types.h             |   1 -
 include/linux/page-flags.h           | 104 ++++++----
 include/linux/pagemap.h              |   2 +-
 include/linux/zsmalloc.h             |   2 +
 mm/balloon_compaction.c              |  21 ++-
 mm/compaction.c                      |  44 +----
 mm/gup.c                             |   4 +-
 mm/internal.h                        |   2 +-
 mm/ksm.c                             |   4 +-
 mm/memory-failure.c                  |   4 +-
 mm/memory_hotplug.c                  |   8 +-
 mm/migrate.c                         | 271 ++++++++++++++++-----------
 mm/page_alloc.c                      |  12 +-
 mm/page_isolation.c                  |  12 +-
 mm/rmap.c                            |  16 +-
 mm/util.c                            |   6 +-
 mm/vmscan.c                          |   6 +-
 mm/zpdesc.h                          |  15 +-
 mm/zsmalloc.c                        |  29 ++-
 28 files changed, 365 insertions(+), 392 deletions(-)


base-commit: 2e462e10265dcdce546cab85a902b716e2b26d9f
-- 
2.49.0

On 30.06.25 14:59, David Hildenbrand wrote:
> Based on mm/mm-new.
> 
> In the future, as we decouple "struct page" from "struct folio", pages
> that support "non-lru page migration" -- movable_ops page migration
> such as memory balloons and zsmalloc -- will no longer be folios. They
> will not have ->mapping, ->lru, and likely no refcount and no
> page lock. But they will have a type and flags :)
> 
> This is the first part (other parts not written yet) of decoupling
> movable_ops page migration from folio migration.
> 
> In this series, we get rid of the ->mapping usage, and start cleaning up
> the code + separating it from folio migration.
> 
> Migration core will have to be further reworked to not treat movable_ops
> pages like folios. This is the first step into that direction.
> 
> Heavily tested with virtio-balloon and lightly tested with zsmalloc
> on x86-64. Cross-compile-tested.

Thanks everybody for the review!

I'm planning on sending v2 probably later tomorrow, so we can get it 
into mm-new.

So if someone wants to review parts of this series either (a) do it 
until tomorrow; or (b) scream STOP and I'll wait with v2 a bit longer; 
or (c) wait until v2.

-- 
Cheers,

David / dhildenb