Re: [resend][PATCH] mm: increase RECLAIM_DISTANCE to 30

From: Balbir Singh
Date: Fri Oct 08 2010 - 12:59:42 EST


* Christoph Lameter <cl@xxxxxxxxx> [2010-10-08 10:45:16]:

> On Fri, 8 Oct 2010, Balbir Singh wrote:
>
> > I am not sure if this makes sense, since RECLAIM_DISTANCE is supposed
> > to be a hardware parameter. Could you please help clarify what the
> > access latency of a node with RECLAIM_DISTANCE 20 to that of a node
> > with RECLAIM_DISTANCE 30 is? Has the hardware definition of reclaim
> > distance changed?
>
> 10 is the local distance. So 30 should be 3x the latency that a local
> access takes.
>

Does this patch then imply that we should do zone_reclaim only for 3x
nodes and not 2x nodes as we did earlier.

> > I suspect the side effect is the zone_reclaim_mode is not set to 1 on
> > bootup for the 2-4 socket machines you mention, which results in
> > better VM behaviour?
>
> Right.
>

--
Three Cheers,
Balbir
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