Re: [RFC PATCH] dt:numa: adding numa node mapping for memory nodes.

[Hanjun Guo <hanjun.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On 2014-9-18 5:48, Nathan Lynch wrote:
> On 09/17/2014 03:56 AM, Ganapatrao Kulkarni wrote:
>> From: Ganapatrao Kulkarni <ganapatrao.kulkarni-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
>>
>> This patch adds property "nid" to memory node to provide the memory range to
>> numa node id mapping.
>>
>> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
>>
>> ---
>>  Documentation/devicetree/bindings/numa.txt | 58 ++++++++++++++++++++++++++++++
>>  1 file changed, 58 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/numa.txt
>>
>> diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt
>> new file mode 100644
>> index 0000000..c4a94f2
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/numa.txt
>> @@ -0,0 +1,58 @@
>> +======================================================
>> +numa id binding description
>> +======================================================
>> +
>> +======================================================
>> +1 - Introduction
>> +======================================================
>> +The device node  property "nid(numa node id)" can be added to memory
>> +device node to map the range of memory addresses as defined in property "reg".
>> +The property "nid" maps the memory range to the numa node id, which is used to
>> +find the local and remory pages on numa aware systems.
> 
> "Local" and "remote" memory are notions that relate to some other
> resource -- typically a CPU, but also I/O resources on some systems.  It
> seems to me that a useful NUMA binding would at least specify a "nid"
> property, or something like it, for both cpu and memory nodes.  But this
> document speaks only of memory nodes.

Agreed. and more, I think I/O resources also need such property, it will
have performance influence for the proximity domain of I/O devices too.

Thanks
Hanjun

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