[PATCH] mm: add lazyfree folio to lru tail

[gaoxu <gaoxu2@honor.com>]

Replace lruvec_add_folio with lruvec_add_folio_tail in the lru_lazyfree_fn:
1. The lazy-free folio is added to the LRU_INACTIVE_FILE list. If it's
   moved to the LRU tail, it allows for faster release lazy-free folio and
   reduces the impact on file refault.
2. When mglru is enabled, the lazy-free folio is reclaimabled and should be
   added using lru_gen_add_folio(lruvec, folio, true) instead of
   lru_gen_add_folio(lruvec, folio, false) for adding to gen.

With the change in place, workingset_refault_file is reduced by 33% in the
continuous startup testing of the applications in the Android system.

Signed-off-by: gao xu <gaoxu2@hihonor.com>
---
 mm/swap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/swap.c b/mm/swap.c
index 67786cb77..ed49643ec 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -635,7 +635,7 @@ static void lru_lazyfree_fn(struct lruvec *lruvec, struct folio *folio)
 		 * anonymous folios
 		 */
 		folio_clear_swapbacked(folio);
-		lruvec_add_folio(lruvec, folio);
+		lruvec_add_folio_tail(lruvec, folio);
 
 		__count_vm_events(PGLAZYFREE, nr_pages);
 		__count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
-- 
2.17.1