vmscan: count pages into balanced for zone with good watermark

It's possible a zone watermark is ok when entering the balance_pgdat()
loop, while the zone is within the requested classzone_idx.  Count pages
from this zone into `balanced'.  In this way, we can skip shrinking zones
too much for high order allocation.

Signed-off-by: Shaohua Li <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Reviewed-by: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 2 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index a297603d35bc..77ee24fc891a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2748,6 +2748,8 @@ out:
 
 			/* If balanced, clear the congested flag */
 			zone_clear_flag(zone, ZONE_CONGESTED);
+			if (i <= *classzone_idx)
+				balanced += zone->present_pages;
 		}
 	}