Commit 6ef0c197 authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

mm/migrate: rename isolate_movable_page() to isolate_movable_ops_page() 

...  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().

Note that we will leave anything that needs a rework (lock, refcount,
->lru) to be using folios for now: that perfectly highlights the
problematic bits.

Link: https://lkml.kernel.org/r/20250704102524.326966-8-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarZi Yan <ziy@nvidia.com>
Reviewed-by: default avatarHarry Yoo <harry.yoo@oracle.com>
Reviewed-by: default avatarLorenzo 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 5ec35833

include/linux/migrate.h

+2 −2
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free, 
		  unsigned long private, enum migrate_mode mode, int reason,

		  unsigned int *ret_succeeded);

struct folio *alloc_migration_target(struct folio *src, unsigned long private);

bool isolate_movable_page(struct page *page, isolate_mode_t mode);

bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode);

bool isolate_folio_to_list(struct folio *folio, struct list_head *list);



int migrate_huge_page_move_mapping(struct address_space *mapping,
@@ -90,7 +90,7 @@ static inline int migrate_pages(struct list_head *l, new_folio_t new, 
static inline struct folio *alloc_migration_target(struct folio *src,

		unsigned long private)

	{ return NULL; }

static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode)

static inline bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)

	{ return false; }

static inline bool isolate_folio_to_list(struct folio *folio, struct list_head *list)

	{ return false; }

mm/compaction.c

+1 −1
Original line number Diff line number Diff line
@@ -1093,7 +1093,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, 
					locked = NULL;

				}



				if (isolate_movable_page(page, mode)) {

				if (isolate_movable_ops_page(page, mode)) {

					folio = page_folio(page);

					goto isolate_success;

				}

mm/migrate.c

+29 −10
Original line number Diff line number Diff line
@@ -51,8 +51,26 @@ 
#include "internal.h"

#include "swap.h"



bool isolate_movable_page(struct page *page, isolate_mode_t mode)

/**

 * isolate_movable_ops_page - isolate a movable_ops page for migration

 * @page: The page.

 * @mode: The isolation mode.

 *

 * Try to isolate a movable_ops page for migration. Will fail if the page is

 * not a movable_ops page, if the page is already isolated for migration

 * or if the page was just was released by its owner.

 *

 * Once isolated, the page cannot get freed until it is either putback

 * or migrated.

 *

 * Returns true if isolation succeeded, otherwise false.

 */

bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)

{

	/*

	 * TODO: these pages will not be folios in the future. All

	 * folio dependencies will have to be removed.

	 */

	struct folio *folio = folio_get_nontail_page(page);

	const struct movable_operations *mops;
@@ -73,7 +91,7 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode) 
	 * we use non-atomic bitops on newly allocated page flags so

	 * unconditionally grabbing the lock ruins page's owner side.

	 */

	if (unlikely(!__folio_test_movable(folio)))

	if (unlikely(!__PageMovable(page)))

		goto out_putfolio;



	/*
@@ -90,18 +108,19 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode) 
	if (unlikely(!folio_trylock(folio)))

		goto out_putfolio;



	if (!folio_test_movable(folio) || folio_test_isolated(folio))

	if (!PageMovable(page) || PageIsolated(page))

		goto out_no_isolated;



	mops = folio_movable_ops(folio);

	VM_BUG_ON_FOLIO(!mops, folio);

	mops = page_movable_ops(page);

	if (WARN_ON_ONCE(!mops))

		goto out_no_isolated;



	if (!mops->isolate_page(&folio->page, mode))

	if (!mops->isolate_page(page, mode))

		goto out_no_isolated;



	/* Driver shouldn't use the isolated flag */

	WARN_ON_ONCE(folio_test_isolated(folio));

	folio_set_isolated(folio);

	VM_WARN_ON_ONCE_PAGE(PageIsolated(page), page);

	SetPageIsolated(page);

	folio_unlock(folio);



	return true;
@@ -175,7 +194,7 @@ bool isolate_folio_to_list(struct folio *folio, struct list_head *list) 
	if (lru)

		isolated = folio_isolate_lru(folio);

	else

		isolated = isolate_movable_page(&folio->page,

		isolated = isolate_movable_ops_page(&folio->page,

						    ISOLATE_UNEVICTABLE);



	if (!isolated)