Commit be4a3e9c authored Jul 04, 2025 by David Hildenbrand Committed by Andrew Morton Jul 13, 2025

mm/migrate: move movable_ops page handling out of move_to_new_folio()

Let's move that handling directly into migrate_folio_move(), so we can
simplify move_to_new_folio().  While at it, fixup the documentation a bit.

Note that unmap_and_move_huge_page() does not care, because it only deals
with actual folios.  (we only support migration of individual movable_ops
pages)

Link: https://lkml.kernel.org/r/20250704102524.326966-12-david@redhat.com


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

parent 07e5355e

mm/migrate.c

+30 −33

Original line number	Diff line number	Diff line
		@@ -1026,11 +1026,12 @@ static int fallback_migrate_folio(struct address_space *mapping,
		}

		/*
		* Move a page to a newly allocated page
		* The page is locked and all ptes have been successfully removed.
		* Move a src folio to a newly allocated dst folio.
		*
		* The new page will have replaced the old page if this function
		* is successful.
		* The src and dst folios are locked and the src folios was unmapped from
		* the page tables.
		*
		* On success, the src folio was replaced by the dst folio.
		*
		* Return value:
		* < 0 - error code
		@@ -1039,15 +1040,12 @@ static int fallback_migrate_folio(struct address_space *mapping,
		static int move_to_new_folio(struct folio dst, struct folio src,
		enum migrate_mode mode)
		{
		struct address_space *mapping = folio_mapping(src);
		int rc = -EAGAIN;
		bool is_lru = !__folio_test_movable(src);

		VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
		VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);

		if (likely(is_lru)) {
		struct address_space *mapping = folio_mapping(src);

		if (!mapping)
		rc = migrate_folio(mapping, dst, src, mode);
		else if (mapping_inaccessible(mapping))
		@@ -1065,8 +1063,7 @@ static int move_to_new_folio(struct folio dst, struct folio src,
		else
		rc = fallback_migrate_folio(mapping, dst, src, mode);

		if (rc != MIGRATEPAGE_SUCCESS)
		goto out;
		if (rc == MIGRATEPAGE_SUCCESS) {
		/*
		* For pagecache folios, src->mapping must be cleared before src
		* is freed. Anonymous folios must stay anonymous until freed.
		@@ -1076,10 +1073,7 @@ static int move_to_new_folio(struct folio dst, struct folio src,

		if (likely(!folio_is_zone_device(dst)))
		flush_dcache_folio(dst);
		} else {
		rc = migrate_movable_ops_page(&dst->page, &src->page, mode);
		}
		out:
		return rc;
		}

		@@ -1330,19 +1324,22 @@ static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private,
		int rc;
		int old_page_state = 0;
		struct anon_vma *anon_vma = NULL;
		bool is_lru = !__folio_test_movable(src);
		struct list_head *prev;

		__migrate_folio_extract(dst, &old_page_state, &anon_vma);
		prev = dst->lru.prev;
		list_del(&dst->lru);

		rc = move_to_new_folio(dst, src, mode);
		if (unlikely(__folio_test_movable(src))) {
		rc = migrate_movable_ops_page(&dst->page, &src->page, mode);
		if (rc)
		goto out;

		if (unlikely(!is_lru))
		goto out_unlock_both;
		}

		rc = move_to_new_folio(dst, src, mode);
		if (rc)
		goto out;

		/*
		* When successful, push dst to LRU immediately: so that if it