Re: [PATCH] xend: Fix non-contiguous NUMA node assignment

[Andre Przywara <andre.przywara@amd.com>]

Keir Fraser wrote:
> I had a go myself: see c/s 20817. This keeps nr_nodes as well as
> max_node_id, and continues to use it where it seemed to make sense to do so.

c/s 20817 seems OK to me. Actually that was how I started, but then 
decided to drop max_node_id because I didn't see the sense in keeping 
two variables which actually differ just by 1. But I didn't consider 
chunk #3 of XendDomainInfo.py, which actually also fixes another bug.

Thanks!
Regards,
Andre.

> 
>  -- Keir
> 
> On 17/01/2010 17:48, "Keir Fraser" <keir.fraser@eu.citrix.com> wrote:
> 
>> nr_nodes was always num_online_nodes() returned by Xen -- not accounting for
>> holes in node id space. Hance I emulated that behaviour from the Python
>> extension package. If what you actually want everywhere in the Python code
>> is max_node_id, then please remove the nr_nodes code from xc.c and all
>> references to it from the Python code. I agree that using max_node_id seems
>> more correct than nr_nodes -- the intention was for someone to plumb that
>> new field properly into the Python code anyway.
>>
>>  -- Keir
>>
>> On 15/01/2010 13:28, "Andre Przywara" <andre.przywara@amd.com> wrote:
>>
>>> Hi,
>>>
>>> it seems that I missed a point in this whole addition of max_node_id. I
>>> see the difference in the Xen HV part, so nr_nodes got replaced with
>>> max_node_id in physinfo_t (and xc_physinfo_t, respectively).
>>> But where does this value help in xend? There is no single Python
>>> reference to the physinfo()'s max_node_id field, instead all functions
>>> use the old (but now bogus) nr_nodes variable.
>>> So in the attached patch I kept the xc.physinfo() returned dictionary
>>> with only a nr_nodes field, calculated by simply adding 1 to max_node_id
>>> from libxc. Empty nodes can (and will) be detected by iterating through
>>> the node_to_cpus and node_to_memory lists.
>>> Nodes without memory should not be considered during guest's memory
>>> allocation, but will be used for further CPU affinity setting if the
>>> number of VCPUs exceeds the number of cores per node.
>>>
>>> Please correct me if I am totally wrong on this, but this seems to work
>>> much better in my case.
>>>
>>> Regards,
>>> Andre.
>>>
>>> Signed-off-by: Andre Przywara <andre.przywara@amd.com>
>>
>>
>> _______________________________________________
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>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
> 
> 
> 

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
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