Re: [patch 2/2] enables booting a NUMA system where some nodes have no memory

KAMEZAWA Hiroyuki
2006-11-16T00:59:45Z

On Wed, 15 Nov 2006 14:51:26 -0800 (PST)
Christoph Lameter <clameter@sgi.com> wrote:

> On Wed, 15 Nov 2006, Martin Bligh wrote:
>
> > Supposing we hot-unplugged all the memory in a node? Or seems to have
> > happened in this instance is boot with mem=, cutting out memory on that
> > node.
>
> So a node with no memory has a pgdat_list structure but no zones? Or empty
> zones?
>

The node has just empty-zone. pgdat/per-cpu-area is allocated on an other
(nearest) node.

I hear some vender's machine has this configuration. (ia64, maybe SGI or HP)

Node0: CPUx0 + XXXGb memory
Node1: CPUx2 + 16MB memory
Node2: CPUx2 + 16MB memory

memory of Node1 and Node2 is tirmmed at boot by GRANULE alignment.
Then, final view is
Node0 : memory-only-node
Node1 : cpu-only-node
Node2 : cpu-only-node.

-Kame