Date: Tue, 13 Feb 2007 17:38:30 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, akpm@osdl.org, clameter@sgi.com,
       bob.picco@hp.com
Subject: Re: [RFC] [PATCH] more support for memory-less-node.
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	<200702130929.49349.andi@firstfloor.org>
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On Tue, 13 Feb 2007 09:29:49 +0100
Andi Kleen <andi@firstfloor.org> wrote:

> 
> > In my understanding, a "node" is a block of cpu, memory, devices.
> > and there could be cpu-only-node, memory-only-node, device-only-node...
> 
> The trouble with this is that you'll need to harden large parts
> of code against these.  Especially a NULL pgdat is something quite
> dangerous. You could make it a dummy empty pgdat, but just assigning it
> nearby seems easier.

Ah...It seems I didn't explain enough.

Now, memorly-less-node has its own pgdat, for its own zonelist.
All *online* node has its own NODA_DATA(nid).

NOD_DATA(nid) is always valid pointer if a node is online.
NODE_DATA(nid)->present_pages can be 0 even if a node is online, 
I call this as memory-less-node.

Thanks,
-Kame


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