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-rw-r--r--mm/compaction.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index e5995f38d677..cd93ea24c565 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1438,6 +1438,11 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
{
struct zone *zone;
struct zoneref *z;
+ pg_data_t *last_pgdat = NULL;
+
+ /* Do not retry compaction for zone-constrained allocations */
+ if (ac->high_zoneidx < ZONE_NORMAL)
+ return false;
/*
* Make sure at least one zone would pass __compaction_suitable if we continue
@@ -1448,14 +1453,27 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
unsigned long available;
enum compact_result compact_result;
+ if (last_pgdat == zone->zone_pgdat)
+ continue;
+
+ /*
+ * This over-estimates the number of pages available for
+ * reclaim/compaction but walking the LRU would take too
+ * long. The consequences are that compaction may retry
+ * longer than it should for a zone-constrained allocation
+ * request.
+ */
+ last_pgdat = zone->zone_pgdat;
+ available = pgdat_reclaimable_pages(zone->zone_pgdat) / order;
+
/*
* Do not consider all the reclaimable memory because we do not
* want to trash just for a single high order allocation which
* is even not guaranteed to appear even if __compaction_suitable
* is happy about the watermark check.
*/
- available = zone_reclaimable_pages(zone) / order;
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
+ available = min(zone->managed_pages, available);
compact_result = __compaction_suitable(zone, order, alloc_flags,
ac_classzone_idx(ac), available);
if (compact_result != COMPACT_SKIPPED &&