From 32a331a72f3eec30f65fd929aeb4dfc514eca28f Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 12 May 2022 20:22:59 -0700 Subject: [PATCH] mm/vmscan: add a comment about MADV_FREE pages check in folio_check_dirty_writeback Patch series "A few cleanup and fixup patches for vmscan This series contains a few patches to remove obsolete comment, introduce helper to remove duplicated code and so no. Also we take all base pages of THP into account in rare race condition. More details can be found in the respective changelogs. This patch (of 6): The MADV_FREE pages check in folio_check_dirty_writeback is a bit hard to follow. Add a comment to make the code clear. Link: https://lkml.kernel.org/r/20220425111232.23182-2-linmiaohe@huawei.com Suggested-by: Huang, Ying Signed-off-by: Miaohe Lin Reviewed-by: Christoph Hellwig Reviewed-by: Oscar Salvador Cc: Joonsoo Kim Signed-off-by: Andrew Morton --- mm/vmscan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 726f5ce366daf..4ea23807d23fb 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1435,7 +1435,10 @@ static void folio_check_dirty_writeback(struct folio *folio, /* * Anonymous pages are not handled by flushers and must be written - * from reclaim context. Do not stall reclaim based on them + * from reclaim context. Do not stall reclaim based on them. + * MADV_FREE anonymous pages are put into inactive file list too. + * They could be mistakenly treated as file lru. So further anon + * test is needed. */ if (!folio_is_file_lru(folio) || (folio_test_anon(folio) && !folio_test_swapbacked(folio))) { -- 2.30.2