On Thu, Aug 15, 2013 at 06:02:53PM +0800, Hillf Danton wrote: > If the allocation order is not high, direct compaction does nothing. > Can we skip compaction here if order drops to zero? > If the allocation order is not high then pgdat_needs_compaction == (order > 0) == false == no calling compact_pdatt In the case where order is reset to 0 due to fragmentation then it does call compact_pgdat but it does no work due to the cc->order check in __compact_pgdat. -- Mel Gorman SUSE Labs -- 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>