[PATCH RFC 15/29] mm/migration: remove PageMovable()
From: David Hildenbrand <hidden>
Date: 2025-06-18 17:41:04
Also in:
linux-doc, linux-fsdevel, linux-mm, lkml, virtualization
Subsystem:
memory management, memory management - memory policy and migration, memory management - page allocator, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Vlastimil Babka, Linus Torvalds
As __ClearPageMovable() is gone that would have only made PageMovable()==false but still __PageMovable()==true, now PageMovable() == __PageMovable(). So we can replace PageMovable() checks by __PageMovable(). In fact, __PageMovable() cannot change until a page is freed, so we can turn some PageMovable() into sanity checks for __PageMovable(). Signed-off-by: David Hildenbrand <redacted> --- include/linux/migrate.h | 2 -- mm/compaction.c | 15 --------------- mm/migrate.c | 18 ++++++++++-------- 3 files changed, 10 insertions(+), 25 deletions(-)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index fb6e9612e9f0b..204e89eac998f 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h@@ -104,10 +104,8 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, #endif /* CONFIG_MIGRATION */ #ifdef CONFIG_COMPACTION -bool PageMovable(struct page *page); void __SetPageMovable(struct page *page, const struct movable_operations *ops); #else -static inline bool PageMovable(struct page *page) { return false; } static inline void __SetPageMovable(struct page *page, const struct movable_operations *ops) {
diff --git a/mm/compaction.c b/mm/compaction.c
index 889ec696ba96a..5c37373017014 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c@@ -114,21 +114,6 @@ static unsigned long release_free_list(struct list_head *freepages) } #ifdef CONFIG_COMPACTION -bool PageMovable(struct page *page) -{ - const struct movable_operations *mops; - - VM_BUG_ON_PAGE(!PageLocked(page), page); - if (!__PageMovable(page)) - return false; - - mops = page_movable_ops(page); - if (mops) - return true; - - return false; -} - void __SetPageMovable(struct page *page, const struct movable_operations *mops) { VM_BUG_ON_PAGE(!PageLocked(page), page);
diff --git a/mm/migrate.c b/mm/migrate.c
index db807f9bbf975..cf92075108f0c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -87,9 +87,12 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode) goto out; /* - * Check movable flag before taking the page lock because + * Check for movable_ops pages before taking the page lock because * we use non-atomic bitops on newly allocated page flags so * unconditionally grabbing the lock ruins page's owner side. + * + * Note that once a page has movable_ops, it will stay that way + * until the page was freed. */ if (unlikely(!__PageMovable(page))) goto out_putfolio;
@@ -108,7 +111,8 @@ bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode) if (unlikely(!folio_trylock(folio))) goto out_putfolio; - if (!PageMovable(page) || PageIsolated(page)) + VM_WARN_ON_ONCE_PAGE(!__PageMovable(page), page); + if (PageIsolated(page)) goto out_no_isolated; mops = page_movable_ops(page);
@@ -149,11 +153,10 @@ static void putback_movable_ops_page(struct page *page) */ struct folio *folio = page_folio(page); + VM_WARN_ON_ONCE_PAGE(!__PageMovable(page), page); VM_WARN_ON_ONCE_PAGE(!PageIsolated(page), page); folio_lock(folio); - /* If the page was released by it's owner, there is nothing to do. */ - if (PageMovable(page)) - page_movable_ops(page)->putback_page(page); + page_movable_ops(page)->putback_page(page); ClearPageIsolated(page); folio_unlock(folio); folio_put(folio);
@@ -189,10 +192,9 @@ static int migrate_movable_ops_page(struct page *dst, struct page *src, { int rc = MIGRATEPAGE_SUCCESS; + VM_WARN_ON_ONCE_PAGE(!__PageMovable(src), src); VM_WARN_ON_ONCE_PAGE(!PageIsolated(src), src); - /* If the page was released by it's owner, there is nothing to do. */ - if (PageMovable(src)) - rc = page_movable_ops(src)->migrate_page(dst, src, mode); + rc = page_movable_ops(src)->migrate_page(dst, src, mode); if (rc == MIGRATEPAGE_SUCCESS) ClearPageIsolated(src); return rc;
--
2.49.0