mm, vmscan: remove duplicate logic clearing node congestion and dirty state

Reclaim may stall if there is too much dirty or congested data on a
node.  This was previously based on zone flags and the logic for
clearing the flags is in two places.  As congestion/dirty tracking is
now tracked on a per-node basis, we can remove some duplicate logic.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Hillf Danton <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 12 insertions, 12 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 01fe4708e404..8b39b903bd14 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3008,7 +3008,17 @@ static bool zone_balanced(struct zone *zone, int order, int classzone_idx)
 {
 	unsigned long mark = high_wmark_pages(zone);
 
-	return zone_watermark_ok_safe(zone, order, mark, classzone_idx);
+	if (!zone_watermark_ok_safe(zone, order, mark, classzone_idx))
+		return false;
+
+	/*
+	 * If any eligible zone is balanced then the node is not considered
+	 * to be congested or dirty
+	 */
+	clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
+	clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
+
+	return true;
 }
 
 /*
@@ -3154,13 +3164,6 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			if (!zone_balanced(zone, order, 0)) {
 				classzone_idx = i;
 				break;
-			} else {
-				/*
-				 * If any eligible zone is balanced then the
-				 * node is not considered congested or dirty.
-				 */
-				clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
-				clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
 			}
 		}
 
@@ -3219,11 +3222,8 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			if (!populated_zone(zone))
 				continue;
 
-			if (zone_balanced(zone, sc.order, classzone_idx)) {
-				clear_bit(PGDAT_CONGESTED, &pgdat->flags);
-				clear_bit(PGDAT_DIRTY, &pgdat->flags);
+			if (zone_balanced(zone, sc.order, classzone_idx))
 				goto out;
-			}
 		}
 
 		/*