diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 32 |
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); } |