From 6f4dd8de4835563de9bae797ce1d7a13465a7a7d Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Tue, 13 Oct 2020 16:52:11 -0700 Subject: [PATCH] mm: remove superfluous __ClearPageActive() To activate a page, mark_page_accessed() always holds a reference on it. It either gets a new reference when adding a page to lru_pvecs.activate_page or reuses an existing one it previously got when it added a page to lru_pvecs.lru_add. So it doesn't call SetPageActive() on a page that doesn't have any reference left. Therefore, the race is impossible these days (I didn't brother to dig into its history). For other paths, namely reclaim and migration, a reference count is always held while calling SetPageActive() on a page. SetPageSlabPfmemalloc() also uses SetPageActive(), but it's irrelevant to LRU pages. Signed-off-by: Yu Zhao Signed-off-by: Andrew Morton Reviewed-by: Yang Shi Cc: Alexander Duyck Cc: David Hildenbrand Cc: Huang Ying Cc: Hugh Dickins Cc: Joonsoo Kim Cc: Mel Gorman Cc: Michal Hocko Cc: Nicholas Piggin Cc: Qian Cai Link: http://lkml.kernel.org/r/20200818184704.3625199-2-yuzhao@google.com Signed-off-by: Linus Torvalds --- mm/memremap.c | 2 -- mm/swap.c | 2 -- 2 files changed, 4 deletions(-) diff --git a/mm/memremap.c b/mm/memremap.c index 532ec3d36ab4..7dc7aec971de 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -494,8 +494,6 @@ void free_devmap_managed_page(struct page *page) return; } - /* Clear Active bit in case of parallel mark_page_accessed */ - __ClearPageActive(page); __ClearPageWaiters(page); mem_cgroup_uncharge(page); diff --git a/mm/swap.c b/mm/swap.c index 82ddefda4904..8c936404f254 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -943,8 +943,6 @@ void release_pages(struct page **pages, int nr) del_page_from_lru_list(page, lruvec, page_off_lru(page)); } - /* Clear Active bit in case of parallel mark_page_accessed */ - __ClearPageActive(page); __ClearPageWaiters(page); list_add(&page->lru, &pages_to_free);