This reverts commit c3096e6782b733158bf34f6bbb4567808d4e0740. That commit made sure we immediately add the new page to the LRU before remove_migration_ptes() is called in migrate_move_folio() (used to be __unmap_and_move() back then), such that the rmap walk will rebuild the correct mlock_count for the page again. This was needed because the mlock_count was lost when the page is isolated. This is no longer the case since mlock_count no longer overlays page->lru. Revert the commit (the code was foliated afterward the commit, so the revert is updated as such). Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx> --- mm/migrate.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 01cac26a3127..68f693731865 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1279,19 +1279,6 @@ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, if (unlikely(!is_lru)) goto out_unlock_both; - /* - * When successful, push dst to LRU immediately: so that if it - * turns out to be an mlocked page, remove_migration_ptes() will - * automatically build up the correct dst->mlock_count for it. - * - * We would like to do something similar for the old page, when - * unsuccessful, and other cases when a page has been temporarily - * isolated from the unevictable LRU: but this case is the easiest. - */ - folio_add_lru(dst); - if (page_was_mapped) - lru_add_drain(); - if (page_was_mapped) remove_migration_ptes(src, dst, false); @@ -1301,9 +1288,16 @@ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased - * refcounter. + * refcounter. As well, if it is LRU folio, add the folio to LRU + * list in here. Use the old state of the isolated source folio to + * determine if we migrated a LRU folio. dst was already unlocked + * and possibly modified by its owner - don't rely on the folio + * state. */ - folio_put(dst); + if (unlikely(!is_lru)) + folio_put(dst); + else + folio_putback_lru(dst); /* * A folio that has been migrated has all references removed -- 2.41.0.162.gfafddb0af9-goog
