Re: NUMA policy issues with ZONE_MOVABLE

Mel Gorman
2007-07-30T12:41:52Z

On Sat, 28 Jul 2007, KAMEZAWA Hiroyuki wrote:

> On Sat, 28 Jul 2007 23:10:32 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>>> H1N1D1H2N2D2H3N3D3 instead of
>>> H1H2H3N1N2N3D1D2D3
>>>
>>> If it's node-order, does this scheme break?
>>>
>>
>> Maybe no. "skip" will point to the nearest available zone anyway.
>> But there may be better scheme. This is jus an easy idea.
>>
> Assume zonelist on Node0,
>
> zone order: M0M1M2M3N0N1N2N3D0 (only node 0 has zone dma)
> node order: M0N0D0M1N1M2N2N3
>
> GFP_KERNEL for zone_order: skip 4, find N0N2N3D0
> GFP_KERNEL for node_order: skip 1, find N0D0N2N3
>
> I'm not sure that this easy trick can show performance benefit.
>

The results from kernbench were mixed. Small improves on some machines and
small regressions on others. I'll keep the patch on the stack and
investigate it further with other benchmarks.

Thanks

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab