summaryrefslogtreecommitdiff
path: root/mm/vmscan.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c32
1 files changed, 23 insertions, 9 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 976be140a8ce..4390a8d5be41 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3539,16 +3539,21 @@ kswapd_try_sleep:
}
/*
- * A zone is low on free memory, so wake its kswapd task to service it.
+ * A zone is low on free memory or too fragmented for high-order memory. If
+ * kswapd should reclaim (direct reclaim is deferred), wake it up for the zone's
+ * pgdat. It will wake up kcompactd after reclaiming memory. If kswapd reclaim
+ * has failed or is not needed, still wake up kcompactd if only compaction is
+ * needed.
*/
-void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
+void wakeup_kswapd(struct zone *zone, gfp_t gfp_flags, int order,
+ enum zone_type classzone_idx)
{
pg_data_t *pgdat;
if (!managed_zone(zone))
return;
- if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL))
+ if (!cpuset_zone_allowed(zone, gfp_flags))
return;
pgdat = zone->zone_pgdat;
pgdat->kswapd_classzone_idx = kswapd_classzone_idx(pgdat,
@@ -3557,14 +3562,23 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
if (!waitqueue_active(&pgdat->kswapd_wait))
return;
- /* Hopeless node, leave it to direct reclaim */
- if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES)
- return;
-
- if (pgdat_balanced(pgdat, order, classzone_idx))
+ /* Hopeless node, leave it to direct reclaim if possible */
+ if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ||
+ pgdat_balanced(pgdat, order, classzone_idx)) {
+ /*
+ * There may be plenty of free memory available, but it's too
+ * fragmented for high-order allocations. Wake up kcompactd
+ * and rely on compaction_suitable() to determine if it's
+ * needed. If it fails, it will defer subsequent attempts to
+ * ratelimit its work.
+ */
+ if (!(gfp_flags & __GFP_DIRECT_RECLAIM))
+ wakeup_kcompactd(pgdat, order, classzone_idx);
return;
+ }
- trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, classzone_idx, order);
+ trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, classzone_idx, order,
+ gfp_flags);
wake_up_interruptible(&pgdat->kswapd_wait);
}