[PATCH v2 1/4] numa_conf.c: add helper functions for cpumap operations

[Daniel Henrique Barboza]

On 6/18/20 7:34 AM, Michal Privoznik wrote:
> On 6/10/20 8:35 PM, Daniel Henrique Barboza wrote:
>> These helpers will be used in an auto-fill feature for incomplete
>> NUMA topologies in the next patch.
>>
>> Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
>> ---
>>   src/conf/numa_conf.c     | 46 ++++++++++++++++++++++++++++++++++++++++
>>   src/conf/numa_conf.h     |  3 +++
>>   src/libvirt_private.syms |  1 +
>>   3 files changed, 50 insertions(+)
>>
>> diff --git a/src/conf/numa_conf.c b/src/conf/numa_conf.c
>> index 09811cb51b..d022685284 100644
>> --- a/src/conf/numa_conf.c
>> +++ b/src/conf/numa_conf.c
>> @@ -1372,3 +1372,49 @@ virDomainNumaGetMemorySize(virDomainNumaPtr numa)
>>       return ret;
>>   }
>> +
>> +
>> +static int
>> +virDomainNumaRemoveCPUsFromMap(virBitmapPtr result, virBitmapPtr exclude)
>> +{
>> +    size_t i;
>> +
>> +    for (i = 0; i < virBitmapSize(exclude); i++) {
>> +        if (!virBitmapIsBitSet(exclude, i))
>> +            continue;
>> +
>> +        if (virBitmapClearBitExpand(result, i) < 0)
>> +            return -1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
> 
> This exactly what virBitmapSubtract() does :-)

Completely forgot about virBitmapSubtract() after I tried to use it
in an earlier interaction of the code and it didn't suit what I
need. Granted, I was doing it a convoluted way of doing what I'm
doing now. virBitmapSubtract really works as a replacement in the
code below.


> 
>> +
>> +int
>> +virDomainNumaFillCPUsInNode(virDomainNumaPtr numa, size_t node,
>> +                            unsigned int maxCpus)
>> +{
>> +    g_autoptr(virBitmap) maxCPUsBitmap = virBitmapNew(maxCpus);
>> +    size_t i;
>> +
>> +    if (node >= virDomainNumaGetNodeCount(numa))
>> +        return -1;
>> +
>> +    virBitmapSetAll(maxCPUsBitmap);
>> +
>> +    for (i = 0; i < numa->nmem_nodes; i++) {
>> +        virBitmapPtr nodeCpus = virDomainNumaGetNodeCpumask(numa, i);
>> +
>> +        if (i == node)
>> +            continue;
>> +
>> +        if (virDomainNumaRemoveCPUsFromMap(maxCPUsBitmap, nodeCpus) < 0)
>> +            return -1;
>> +    }
>> +
>> +    virBitmapFree(numa->mem_nodes[node].cpumask);
>> +    numa->mem_nodes[node].cpumask = g_steal_pointer(&maxCPUsBitmap);
> 
> For some weird reason, I'd feel better if the bitmap is replaced only if it differs. I can't really explain why.

I think it's ok to check for virBitmapEqual() before replacing the
existing one.



DHB

> 
> 
> Michal
>