Re: [PATCH] drivers/base/node.c: export physical address range of given node (Re: NUMA node information for pages)

From: David Rientjes
Date: Fri Apr 11 2014 - 18:14:12 EST


On Fri, 11 Apr 2014, Dave Hansen wrote:

> > So? Who cares if there are non-addressable holes in part of the span?
> > Ulrich, correct me if I'm wrong, but it seems you're looking for just a
> > address-to-nodeid mapping (or pfn-to-nodeid mapping) and aren't actually
> > expecting that there are no holes in a node for things like acpi or I/O or
> > reserved memory.
> ...
> > I think trying to represent holes and handling different memory models and
> > hotplug in special ways is complete overkill.
>
> This isn't just about memory hotplug or different memory models. There
> are systems out there today, in production, that have layouts like this:
>
> |------Node0-----|
> |------Node1-----|
>
> and this:
>
> |------Node0-----|
> |-Node1-|
>

What additional information, in your opinion, can we export to assist
userspace in making this determination that $address is on $nid?
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