On 07/08/2016 11:34 AM, Mel Gorman wrote:
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.
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
I don't think it's that big a side-effect to be concerned. I would be
more worried about frequently dirtying cache lines from other
zone_balanced callers where, but I guess even the calls from
wakeup_kswapd() rarely return true for zone_balanced(), otherwise the
wakeups wouldn't have a reason to happen.
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
---
mm/vmscan.c | 24 ++++++++++++------------
1 file 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;
- }
}
/*
--
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