[libvirt] [PATCH] numa: avoid failure in nodememstats on non-NUMA systems

[Boris Fiuczynski]

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and
Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>

On 10/09/2017 02:57 PM, Boris Fiuczynski wrote:
> Looks good to me.
> 
> On 09/22/2017 04:12 PM, Viktor Mihajlovski wrote:
>> libvirt reports a fake NUMA topology in virConnectGetCapabilities
>> even if built without numactl support. The fake NUMA topology consists
>> of a single cell representing the host's cpu and memory resources.
>> Currently this is the case for ARM and s390[x] RPM builds.
>>
>> A client iterating over NUMA cells obtained via virConnectGetCapabilities
>> and invoking virNodeGetMemoryStats on them will see an internal failure
>> "NUMA isn't available on this host". An example for such a client is
>> VDSM.
>>
>> Since the intention seems to be that libvirt always reports at least
>> a single cell it is necessary to return "fake" node memory statistics
>> matching the previously reported fake cell in case NUMA isn't supported
>> on the system.
>>
>> Signed-off-by: Viktor Mihajlovski <mihajlov at linux.vnet.ibm.com>
>> ---
>>   src/util/virhostmem.c | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/src/util/virhostmem.c b/src/util/virhostmem.c
>> index a9ba278..fa04a37 100644
>> --- a/src/util/virhostmem.c
>> +++ b/src/util/virhostmem.c
>> @@ -267,6 +267,14 @@ virHostMemGetStats(int cellNum ATTRIBUTE_UNUSED,
>>           FILE *meminfo;
>>           int max_node;
>>
>> +        /*
>> +         * Even if built without numactl, libvirt claims
>> +         * to have a one-cells NUMA topology. In such a
>> +         * case return the statistics for the entire host.
>> +         */
>> +        if (!virNumaIsAvailable() && cellNum == 0)
>> +            cellNum = VIR_NODE_MEMORY_STATS_ALL_CELLS;
>> +
>>           if (cellNum == VIR_NODE_MEMORY_STATS_ALL_CELLS) {
>>               if (VIR_STRDUP(meminfo_path, MEMINFO_PATH) < 0)
>>                   return -1;
>>
> 
> 


-- 
Mit freundlichen Grüßen/Kind regards
    Boris Fiuczynski

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