Re: [RFC] [PATCH] more support for memory-less-node.

["Martin J. Bligh" <mbligh@mbligh.org>]

Andi Kleen wrote:
>> Your description of the node is correct, it's an arbitrary container of
>> one or more resources. Not only is this definition flexible, it's also
>> very useful, for memory hotplug, odd types of NUMA boxes, etc.
> 
> I must disagree here. Special cases are always dangerous especially
> if they are hard to regression test. I made this discovery the hard
> way on x86-64 ... It's best to eliminate them in the first place,
> otherwise they will later come back and bite you when you don't expect it.
> 
> Adding NULL tests all over mm for this would seem like a clear case
> of this to me.

I wasn't suggesting having NULL pointers for pgdats, if that's what you
mean. Just nodes with no memory in them, the pgdat would still be there.
pgdat = struct node, except everything's badly named.