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 --- lib/show_mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/show_mem.c b/lib/show_mem.c index 0beaa1d899aa..eefe67d50e84 100644 --- a/lib/show_mem.c +++ b/lib/show_mem.c @@ -28,7 +28,7 @@ void show_mem(unsigned int filter, nodemask_t *nodemask) continue; total += zone->present_pages; - reserved += zone->present_pages - zone->managed_pages; + reserved += zone->present_pages - zone_managed_pages(zone); if (is_highmem_idx(zoneid)) highmem += zone->present_pages; -- cgit