Re: [PATCH x86/mm] x86-64, NUMA: Don't assume phys node 0 isalways online in numa_emulation() handling

From: Tejun Heo
Date: Sat Mar 05 2011 - 02:50:50 EST


On Fri, Mar 04, 2011 at 01:33:29PM -0800, David Rientjes wrote:
> On Fri, 4 Mar 2011, Tejun Heo wrote:
>
> > Undetermined entries in emu_nid_to_phys[] are filled with zero
> > assuming that physical node 0 is always online; however, this might
> > not be true depending on hardware configuration. Find a physical node
> > which is actually online and use it instead.
> >
>
> I still don't understand why emu_nid_to_phys[] can't return NUMA_NO_NODE
> and this needs to be done at all. An emulated node should be mapped to a
> physical node based on the address ranges of that emulated node, so it's
> impossible for that to not map directly to a physical online node. We
> don't support memoryless emulated nodes for hotpluggable SRAT entries.

Me neither. That was the original logic. I just transformed the
logic into emu_nid_to_phys[]. If you think you can remove that
safely, please go ahead and submit a patch. That said, it's not
exactly high priority thing to do.

Thanks.

--
tejun
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