[PATCH v1 21/29] mm: rename PG_isolated to PG_movable_ops_isolated

David Hildenbrand
2025-06-30T13:01:22Z

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

While at it, define the flag only with CONFIG_MIGRATION.

Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/page-flags.h | 16 +++++++++++-----
mm/compaction.c | 2 +-
mm/migrate.c | 14 +++++++-------
3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 016a6e6fa428a..aa48b05536bca 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
@@ -1146,8 +1143,17 @@ PAGEFLAG(Isolated, isolated, PF_ANY);
* page_has_movable_ops() instead.
*/
PAGEFLAG(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
PAGEFLAG_FALSE(MovableOps, movable_ops);
+PAGEFLAG_FALSE(MovableOpsIsolated, movable_ops_isolated);
#endif

/**
diff --git a/mm/compaction.c b/mm/compaction.c
index 349f4ea0ec3e5..bf021b31c7ece 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 c6c9998014ec8..62a3ee590b245 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);
}
@@ -216,10 +216,10 @@ 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;
}

--
2.49.0