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Date: Tue, 18 Feb 2014 10:57:09 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [RFC PATCH 2/3] topology: support node_numa_mem() for determining
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Cc: Han Pingtian <hanpt@linux.vnet.ibm.com>,
 Nishanth Aravamudan <nacc@linux.vnet.ibm.com>, Matt Mackall <mpm@selenic.com>,
 Pekka Enberg <penberg@kernel.org>,
 Linux Memory Management List <linux-mm@kvack.org>,
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On Mon, 17 Feb 2014, Joonsoo Kim wrote:

> On Wed, Feb 12, 2014 at 10:51:37PM -0800, Nishanth Aravamudan wrote:
> > Hi Joonsoo,
> > Also, given that only ia64 and (hopefuly soon) ppc64 can set
> > CONFIG_HAVE_MEMORYLESS_NODES, does that mean x86_64 can't have
> > memoryless nodes present? Even with fakenuma? Just curious.

x86_64 currently does not support memoryless nodes otherwise it would
have set CONFIG_HAVE_MEMORYLESS_NODES in the kconfig. Memoryless nodes are
a bit strange given that the NUMA paradigm is to have NUMA nodes (meaning
memory) with processors. MEMORYLESS nodes means that we have a fake NUMA
node without memory but just processors. Not very efficient. Not sure why
people use these configurations.

> I don't know, because I'm not expert on NUMA system :)
> At first glance, fakenuma can't be used for testing
> CONFIG_HAVE_MEMORYLESS_NODES. Maybe some modification is needed.

Well yeah. You'd have to do some mods to enable that testing.