[PATCH] mmotm: memcg-mm-introduce-lowlimit-reclaim-fix.patch

[Michal Hocko]

Use reclaim eligibility rather than low_limit. Generic code doesn't
have to be aware of the reason why a group is not eligible.
---
 mm/vmscan.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8ecf323a1c81..f195a0db5fbb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2215,8 +2215,15 @@ static inline bool should_continue_reclaim(struct zone *zone,
 	}
 }
 
+/**
+ * __shrink_zone - shrinks a given zone
+ *
+ * @zone: zone to shrink
+ * @sc: scan control with additional reclaim parameters
+ * @check_memcg_eligible: check each memcg whether it is eligible for reclaim
+ */
 static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc,
-		bool follow_low_limit)
+		bool check_memcg_eligible)
 {
 	unsigned long nr_reclaimed, nr_scanned;
 	unsigned nr_scanned_groups = 0;
@@ -2237,10 +2244,10 @@ static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc,
 			struct lruvec *lruvec;
 
 			/*
-			 * Memcg might be under its low limit so we have to
-			 * skip it during the first reclaim round
+			 * Memcg might be protected from the reclaim so we have
+			 * to skip it during the first reclaim round
 			 */
-			if (follow_low_limit &&
+			if (check_memcg_eligible &&
 					!mem_cgroup_reclaim_eligible(memcg, root)) {
 				/*
 				 * It would be more optimal to skip the memcg
@@ -2289,8 +2296,8 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc)
 	if (!__shrink_zone(zone, sc, true)) {
 		/*
 		 * First round of reclaim didn't find anything to reclaim
-		 * because of low limit protection so try again and ignore
-		 * the low limit this time.
+		 * because of the reclaim protection so try again and ignore
+		 * reclaim eligibility of memcgs.
 		 */
 		__shrink_zone(zone, sc, false);
 	}
-- 
2.0.0.rc0

-- 
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/