Re: [Lhns-devel] Re: Who's doing what with cpu/memory/node hotplug?

Dave Hansen
2004-05-14T01:28:37Z

On Thu, 2004-05-13 at 18:14, Keiichiro Tokunaga wrote:
> On Wed, 12 May 2004 23:50:58 -0700 Dave Hansen <haveblue@us.ibm.com> wrote:
> > Why not? We already export the information about which PCI busses are
> > attached to which NUMA nodes. How are I/O devices different from CPU or
> > memory?
>
> I have just one concern.
> How about a container device that contains IO devices only?
> - Does it count as a NUMA node?
> - Is it having a NUMA node ID?

I don't see any real reasons why we can't make I/O only nodes. I know
that we've run into and fixed a few situations where a node came up with
either no cpus or no memory for various reasons before. Does anybody
have any philosophical objections to having I/O only nodes?

In any case, I'd bet we'll need some form of this eventually. On my
hardware, It's probably possible to hotplug individual CPUs or sections
of memory in such a way that a node has no online cpus or memory. So,
we'll probably have to handle those cases anyway.

This seems familliar somehow. I have the feeling it's been discussed
before. Matt, does this ring a bell?

-- Dave