From 785b99febb33db0e7779b6293ca34945a1269e21 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 28 Jul 2016 15:47:23 -0700 Subject: [PATCH] mm, vmscan: release/reacquire lru_lock on pgdat change With node-lru, the locking is based on the pgdat. As Minchan pointed out, there is an opportunity to reduce LRU lock release/acquire in check_move_unevictable_pages by only changing lock on a pgdat change. [mgorman@techsingularity.net: remove double initialisation] Link: http://lkml.kernel.org/r/20160719074835.GC10438@techsingularity.net Link: http://lkml.kernel.org/r/1468853426-12858-3-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Johannes Weiner Cc: Minchan Kim Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 4978ee9b5892..22aec2bcfeec 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3774,24 +3774,23 @@ int page_evictable(struct page *page) void check_move_unevictable_pages(struct page **pages, int nr_pages) { struct lruvec *lruvec; - struct zone *zone = NULL; + struct pglist_data *pgdat = NULL; int pgscanned = 0; int pgrescued = 0; int i; for (i = 0; i < nr_pages; i++) { struct page *page = pages[i]; - struct zone *pagezone; + struct pglist_data *pagepgdat = page_pgdat(page); pgscanned++; - pagezone = page_zone(page); - if (pagezone != zone) { - if (zone) - spin_unlock_irq(zone_lru_lock(zone)); - zone = pagezone; - spin_lock_irq(zone_lru_lock(zone)); + if (pagepgdat != pgdat) { + if (pgdat) + spin_unlock_irq(&pgdat->lru_lock); + pgdat = pagepgdat; + spin_lock_irq(&pgdat->lru_lock); } - lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat); + lruvec = mem_cgroup_page_lruvec(page, pgdat); if (!PageLRU(page) || !PageUnevictable(page)) continue; @@ -3807,10 +3806,10 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages) } } - if (zone) { + if (pgdat) { __count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); __count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned); - spin_unlock_irq(zone_lru_lock(zone)); + spin_unlock_irq(&pgdat->lru_lock); } } #endif /* CONFIG_SHMEM */ -- 2.20.1