> > What's the point of this indirection other than another way of avoiding > > empty node 0? > > Honestly, I do not have any idea. I've traced it down to > Author: Andi Kleen <ak@xxxxxxx> > Date: Tue Jan 11 15:35:48 2005 -0800 I don't remember all the details, and I can't even find the commit (is it in linux-historic?). But AFAIK there's no guarantee PXMs are small and continuous, so it seemed better to have a clean zero based space. Back then we had a lot of problems with buggy SRAT tables in BIOS, so we really tried to avoid trusting the BIOS as much as possible. -Andi