[PATCH 09/10] mm: vmscan: Check if kswapd should writepage once per pgdat scan

[Mel Gorman]

Currently kswapd checks if it should start writepage as it shrinks
each zone without taking into consideration if the zone is balanced or
not. This is not wrong as such but it does not make much sense either.
This patch checks once per pgdat scan if kswapd should be writing pages.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
---
 mm/vmscan.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0fa588d..d45f6e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2846,6 +2846,13 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 		}
 
 		/*
+		 * If we're getting trouble reclaiming, start doing writepage
+		 * even in laptop mode.
+		 */
+		if (sc.priority < DEF_PRIORITY - 2)
+			sc.may_writepage = 1;
+
+		/*
 		 * Now scan the zone in the dma->highmem direction, stopping
 		 * at the last zone which needs scanning.
 		 *
@@ -2917,13 +2924,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 					raise_priority = false;
 			}
 
-			/*
-			 * If we're getting trouble reclaiming, start doing
-			 * writepage even in laptop mode.
-			 */
-			if (sc.priority < DEF_PRIORITY - 2)
-				sc.may_writepage = 1;
-
 			if (zone->all_unreclaimable) {
 				if (end_zone && end_zone == i)
 					end_zone--;
-- 
1.8.1.4

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