vmscan: kswapd: don't retry balance_pgdat() if all zones are unreclai…

…mable Commit f50de2d (vmscan: have kswapd sleep for a short interval and double check it should be asleep) can cause kswapd to enter an infinite loop if running on a single-CPU system. If all zones are unreclaimble, sleeping_prematurely return 1 and kswapd will call balance_pgdat() again. but it's totally meaningless, balance_pgdat() doesn't anything against unreclaimable zone! Signed-off-by: KOSAKI Motohiro <[email protected]> Cc: Mel Gorman <[email protected]> Reported-by: Will Newton <[email protected]> Reviewed-by: Minchan Kim <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Tested-by: Will Newton <[email protected]> Reviewed-by: Wu Fengguang <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
iegor · Jan 16, 2010 · de3fab3 · de3fab3
1 parent af2422c
commit de3fab3
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/mm/vmscan.c b/mm/vmscan.c
@@ -1922,6 +1922,9 @@ static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
 		if (!populated_zone(zone))
 			continue;
 
+		if (zone_is_all_unreclaimable(zone))
+			continue;
+
 		if (!zone_watermark_ok(zone, order, high_wmark_pages(zone),
 								0, 0))
 			return 1;