From 9198e96c06744517e3b18fce8be6db61e96a3227 Mon Sep 17 00:00:00 2001 From: Daisuke Nishimura Date: Tue, 16 Jun 2009 15:33:15 -0700 Subject: [PATCH] vmscan: handle may_swap more strictly Commit 2e2e425989080cc534fc0fca154cae515f971cf5 ("vmscan,memcg: reintroduce sc->may_swap) add may_swap flag and handle it at get_scan_ratio(). But the result of get_scan_ratio() is ignored when priority == 0, so anon lru is scanned even if may_swap == 0 or nr_swap_pages == 0. IMHO, this is not an expected behavior. As for memcg especially, because of this behavior many and many pages are swapped-out just in vain when oom is invoked by mem+swap limit. This patch is for handling may_swap flag more strictly. Signed-off-by: Daisuke Nishimura Reviewed-by: KOSAKI Motohiro Cc: Minchan Kim Cc: Johannes Weiner Cc: Balbir Singh Acked-by: KAMEZAWA Hiroyuki Cc: Rik van Riel Cc: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index f3a55d1f9ab7..057e44b97aa1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1430,13 +1430,6 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, unsigned long ap, fp; struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); - /* If we have no swap space, do not bother scanning anon pages. */ - if (!sc->may_swap || (nr_swap_pages <= 0)) { - percent[0] = 0; - percent[1] = 100; - return; - } - anon = zone_nr_pages(zone, sc, LRU_ACTIVE_ANON) + zone_nr_pages(zone, sc, LRU_INACTIVE_ANON); file = zone_nr_pages(zone, sc, LRU_ACTIVE_FILE) + @@ -1534,15 +1527,22 @@ static void shrink_zone(int priority, struct zone *zone, enum lru_list l; unsigned long nr_reclaimed = sc->nr_reclaimed; unsigned long swap_cluster_max = sc->swap_cluster_max; + int noswap = 0; - get_scan_ratio(zone, sc, percent); + /* If we have no swap space, do not bother scanning anon pages. */ + if (!sc->may_swap || (nr_swap_pages <= 0)) { + noswap = 1; + percent[0] = 0; + percent[1] = 100; + } else + get_scan_ratio(zone, sc, percent); for_each_evictable_lru(l) { int file = is_file_lru(l); unsigned long scan; scan = zone_nr_pages(zone, sc, l); - if (priority) { + if (priority || noswap) { scan >>= priority; scan = (scan * percent[file]) / 100; } -- 2.20.1