mm: rename PG_isolated to PG_movable_ops_isolated

Let's rename the flag to make it clearer where it applies (not folios
...).

While at it, define the flag only with CONFIG_MIGRATION.

Link: https://lkml.kernel.org/r/20250704102524.326966-22-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@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>

3 files changed, 19 insertions, 13 deletions

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a02a12e51915..92f7152a445e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -167,10 +167,9 @@ enum pageflags {
 	/* Remapped by swiotlb-xen. */
 	PG_xen_remapped = PG_owner_priv_1,
 
-	/* non-lru isolated movable page */
-	PG_isolated = PG_reclaim,
-
 #ifdef CONFIG_MIGRATION
+	/* movable_ops page that is isolated for migration */
+	PG_movable_ops_isolated = PG_reclaim,
 	/* this is a movable_ops page (for selected typed pages only) */
 	PG_movable_ops = PG_uptodate,
 #endif
@@ -1126,8 +1125,6 @@ static inline bool folio_contain_hwpoisoned_page(struct folio *folio)
 
 bool is_free_buddy_page(const struct page *page);
 
-PAGEFLAG(Isolated, isolated, PF_ANY);
-
 #ifdef CONFIG_MIGRATION
 /*
  * This page is migratable through movable_ops (for selected typed pages
@@ -1147,9 +1144,18 @@ PAGEFLAG(Isolated, isolated, PF_ANY);
  */
 TESTPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL);
 SETPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL);
+/*
+ * A movable_ops page has this flag set while it is isolated for migration.
+ * This flag primarily protects against concurrent migration attempts.
+ *
+ * Once migration ended (success or failure), the flag is cleared. The
+ * flag is managed by the migration core.
+ */
+PAGEFLAG(MovableOpsIsolated, movable_ops_isolated, PF_NO_TAIL);
 #else /* !CONFIG_MIGRATION */
 TESTPAGEFLAG_FALSE(MovableOps, movable_ops);
 SETPAGEFLAG_NOOP(MovableOps, movable_ops);
+PAGEFLAG_FALSE(MovableOpsIsolated, movable_ops_isolated);
 #endif /* CONFIG_MIGRATION */
 
 /**
diff --git a/mm/compaction.c b/mm/compaction.c
index 349f4ea0ec3e..bf021b31c7ec 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1051,7 +1051,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		if (!PageLRU(page)) {
 			/* Isolation code will deal with any races. */
 			if (unlikely(page_has_movable_ops(page)) &&
-					!PageIsolated(page)) {
+			    !PageMovableOpsIsolated(page)) {
 				if (locked) {
 					unlock_page_lruvec_irqrestore(locked, flags);
 					locked = NULL;
diff --git a/mm/migrate.c b/mm/migrate.c
index 90ddf906d706..e4e05a98c84e 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -135,7 +135,7 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)
 		goto out_putfolio;
 
 	VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(page), page);
-	if (PageIsolated(page))
+	if (PageMovableOpsIsolated(page))
 		goto out_no_isolated;
 
 	mops = page_movable_ops(page);
@@ -146,8 +146,8 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)
 		goto out_no_isolated;
 
 	/* Driver shouldn't use the isolated flag */
-	VM_WARN_ON_ONCE_PAGE(PageIsolated(page), page);
-	SetPageIsolated(page);
+	VM_WARN_ON_ONCE_PAGE(PageMovableOpsIsolated(page), page);
+	SetPageMovableOpsIsolated(page);
 	folio_unlock(folio);
 
 	return true;
@@ -177,10 +177,10 @@ static void putback_movable_ops_page(struct page *page)
 	struct folio *folio = page_folio(page);
 
 	VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(page), page);
-	VM_WARN_ON_ONCE_PAGE(!PageIsolated(page), page);
+	VM_WARN_ON_ONCE_PAGE(!PageMovableOpsIsolated(page), page);
 	folio_lock(folio);
 	page_movable_ops(page)->putback_page(page);
-	ClearPageIsolated(page);
+	ClearPageMovableOpsIsolated(page);
 	folio_unlock(folio);
 	folio_put(folio);
 }
@@ -218,10 +218,10 @@ static int migrate_movable_ops_page(struct page *dst, struct page *src,
 	int rc = MIGRATEPAGE_SUCCESS;
 
 	VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(src), src);
-	VM_WARN_ON_ONCE_PAGE(!PageIsolated(src), src);
+	VM_WARN_ON_ONCE_PAGE(!PageMovableOpsIsolated(src), src);
 	rc = page_movable_ops(src)->migrate_page(dst, src, mode);
 	if (rc == MIGRATEPAGE_SUCCESS)
-		ClearPageIsolated(src);
+		ClearPageMovableOpsIsolated(src);
 	return rc;
 }