[merged] mm-remove-superfluous-__clearpageactive.patch removed from -mm tree

[merged] mm-remove-superfluous-__clearpageactive.patch removed from -mm tree

[akpm]

The patch titled
     Subject: mm: remove superfluous __ClearPageActive()
has been removed from the -mm tree.  Its filename was
     mm-remove-superfluous-__clearpageactive.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Yu Zhao <yuzhao@google.com>
Subject: 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.

Link: http://lkml.kernel.org/r/20200818184704.3625199-2-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memremap.c |    2 --
 mm/swap.c     |    2 --
 2 files changed, 4 deletions(-)

--- a/mm/memremap.c~mm-remove-superfluous-__clearpageactive
+++ a/mm/memremap.c
@@ -494,8 +494,6 @@ void free_devmap_managed_page(struct pag
 		return;
 	}
 
-	/* Clear Active bit in case of parallel mark_page_accessed */
-	__ClearPageActive(page);
 	__ClearPageWaiters(page);
 
 	mem_cgroup_uncharge(page);
--- a/mm/swap.c~mm-remove-superfluous-__clearpageactive
+++ a/mm/swap.c
@@ -943,8 +943,6 @@ void release_pages(struct page **pages,
 			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);
_

Patches currently in -mm which might be from yuzhao@google.com are

mm-use-self-explanatory-macros-rather-than-2.patch