[PATCH] Fix fake numa on ppc

Benjamin Herrenschmidt benh at kernel.crashing.org
Wed Sep 2 18:51:39 EST 2009


On Tue, 2009-09-01 at 23:03 -0700, David Rientjes wrote:
> On Wed, 2 Sep 2009, Benjamin Herrenschmidt wrote:
> 
> > Since I'm pretty sure there could be CPU less nodes just like there
> > could be memory-less nodes, it would be good if fake numa could
> > simulate them too :-)
> > 
> 
> You don't want to simulate cpu less nodes since they do have affinity to 
> ranges of memory, you want to map each fake node to a cpumask including 
> all cpus with affinity to its memory, map each cpu to one fake node (with 
> memory) that it has physical affinity to, and then give all fake nodes 
> local NUMA distance to those on the same physical node.  Memoryless nodes 
> take care of themselves since they rely purely on node_distance(), so the 
> index into the slit for all fake nodes to those without memory will be the 
> same.

Ok, makes sense, thanks.

Cheers,
Ben.




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