Re: kswapd skips compaction if reclaim order drops to zero?

[Mel Gorman]

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
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