If the allocation order is not high, direct compaction does nothing. Can we skip compaction here if order drops to zero? --- a/mm/vmscan.c Thu Aug 15 17:47:26 2013 +++ b/mm/vmscan.c Thu Aug 15 17:48:58 2013 @@ -3034,7 +3034,7 @@ static unsigned long balance_pgdat(pg_da * Compact if necessary and kswapd is reclaiming at least the * high watermark number of pages as requsted */ - if (pgdat_needs_compaction && sc.nr_reclaimed > nr_attempted) + if (pgdat_needs_compaction && sc.nr_reclaimed > nr_attempted && order) compact_pgdat(pgdat, order); /* -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>