[PATCH v3 2/4] mm/migration: remove unneeded lock page and PageMovable check

From: Miaohe Lin
Date: Wed May 25 2022 - 04:18:34 EST


When non-lru movable page was freed from under us, __ClearPageMovable must
have been done. So we can remove unneeded lock page and PageMovable check
here. Also free_pages_prepare() will clear PG_isolated for us, so we can
further remove ClearPageIsolated as suggested by David.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
mm/migrate.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index e88ebb88fa6f..337336115e43 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1090,15 +1090,10 @@ static int unmap_and_move(new_page_t get_new_page,
return -ENOSYS;

if (page_count(page) == 1) {
- /* page was freed from under us. So we are done. */
+ /* Page was freed from under us. So we are done. */
ClearPageActive(page);
ClearPageUnevictable(page);
- if (unlikely(__PageMovable(page))) {
- lock_page(page);
- if (!PageMovable(page))
- ClearPageIsolated(page);
- unlock_page(page);
- }
+ /* free_pages_prepare() will clear PG_isolated. */
goto out;
}

--
2.23.0