From 9705bea5f833f4fc21d5bef5fce7348427f76ea4 Mon Sep 17 00:00:00 2001 From: Arun KS Date: Fri, 28 Dec 2018 00:34:24 -0800 Subject: mm: convert zone->managed_pages to atomic variable totalram_pages, zone->managed_pages and totalhigh_pages updates are protected by managed_page_count_lock, but readers never care about it. Convert these variables to atomic to avoid readers potentially seeing a store tear. This patch converts zone->managed_pages. Subsequent patches will convert totalram_panges, totalhigh_pages and eventually managed_page_count_lock will be removed. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. Link: http://lkml.kernel.org/r/1542090790-21750-3-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS Suggested-by: Michal Hocko Suggested-by: Vlastimil Babka Reviewed-by: Konstantin Khlebnikov Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Acked-by: Vlastimil Babka Reviewed-by: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memblock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/memblock.c') diff --git a/mm/memblock.c b/mm/memblock.c index 81ae63ca78d0..0068f87af1e8 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1950,7 +1950,7 @@ void reset_node_managed_pages(pg_data_t *pgdat) struct zone *z; for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) - z->managed_pages = 0; + atomic_long_set(&z->managed_pages, 0); } void __init reset_all_zones_managed_pages(void) -- cgit v1.2.3-55-g7522