Re: [PATCH 1/3] Zone reclaim V3: main patch

From: Christoph Lameter
Date: Thu Dec 08 2005 - 16:23:23 EST


On Thu, 8 Dec 2005, Andi Kleen wrote:

> Sorry I made a mistake here earlier. On checking the ACPI spec
> again it's valid to have distances < 20 (e.g. for a 1.5 NUMA factor
> it would be legally 15)

Saw that too.

> So better just check > LOCAL_DISTANCE, not >= 20.

For Altix 20 means that the other node is remote but in the same
enclosure / motherboard. Latency is very low in these cases. I think in
these small configurations it is better to go off node rather than using
the reclaim logic.

Other small configurations may have the same issues.

RECLAIM_DISTANCE can be set per arch if the default is not okay.

> Also a lot of Opteron BIOS get that wrong, but I'm adding some
> sanity checking now so it should work in future.

Great!
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