kswapd skips compaction if reclaim order drops to zero?

[Hillf Danton]

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);

  /*
--
--
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