mm/vmscan.c: consider swap space when deciding whether to continue reclaim

It's pointless to continue reclaiming when we have no swap space and lots
of anon pages in the inactive list.

Without this patch, it is possible when swap is disabled to continue
trying to reclaim when there are only anonymous pages in the system even
though that will not make any progress.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 974162c80edb3d4fd6380d888b9fb2fb7df95d88..b935e6f0d69518b71da8ccb42dffac2ac484d9f5 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2000,8 +2000,9 @@ static inline bool should_continue_reclaim(struct zone *zone,
         * inactive lists are large enough, continue reclaiming
         */
        pages_for_compaction = (2UL << sc->order);
-       inactive_lru_pages = zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON) +
-                               zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE);
+       inactive_lru_pages = zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE);
+       if (nr_swap_pages > 0)
+               inactive_lru_pages += zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
        if (sc->nr_reclaimed < pages_for_compaction &&
                        inactive_lru_pages > pages_for_compaction)
                return true;