[libvirt] Re：Re: [PATCH] add nodeset='all' and default for interleavemode

[peng.hao2 at zte.com.cn]

>On 09/11/2018 04:28 PM, Peng Hao wrote:
>> For interleave mode,sometimes we want to allocate mmeory regularly
>> in all nodes on the host. But different hosts has different node number.
>> So we add nodeset='all' for interleave mode and if nodeset=NULL default
>> nodeset is 'all' for interleave mode.
>> 
>> Signed-off-by: Peng Hao <peng.hao2 at zte.com.cn>
>> ---
>>  src/conf/numa_conf.c | 73 ++++++++++++++++++++++++++++++++++++++++------------
>>  1 file changed, 57 insertions(+), 16 deletions(-)
>
>Firstly, this patch does not pass 'syntax-check'. Secondly, it breaks
>qemuxml2argvtest.
>
I will pay attention to this.
>> +                numa->memory.allnode = true;
>> +            } else {
>Any patch that changes accepted XML needs to go hand in hand with
>documentation and RNG update and a test case.
I will add next.

>> +    if (placement == VIR_DOMAIN_NUMATUNE_PLACEMENT_STATIC &&
>> +        mode == VIR_DOMAIN_NUMATUNE_MEM_INTERLEAVE &&
>> +        numa->memory.allnode) {
>> +        if ((bitmap = virBitmapNew(VIR_DOMAIN_CPUMASK_LEN)) == NULL)
>> +            goto cleanup;
>> +        virBitmapClearAll(bitmap);
>> +        maxnode = numa_max_node();


>So, you're including numa.h to get this function. What if:

>a) numa.h is not available?
>b) what is wrong with virNumaGetMaxNode()?

>> +        for (i = 0; i <= maxnode; i++) {
>> +            if (virBitmapSetBit(bitmap, i) < 0) {
>> +                virBitmapFree(bitmap);
>> +                goto cleanup;
>> +            }
>> +        }
>> +        if (numa->memory.nodeset)
>> +            virBitmapFree(numa->memory.nodeset);
>> +        numa->memory.nodeset = bitmap;
>>      }
>>  
>>      /* setting nodeset when placement auto is invalid */
>> 

>But more importantly, why is this patch needed? I might be missing
>something, but:

>a) you can just not pin the memory to avoid mismatch of NUMA nodes on
>migration,
>b) supply new domain XML on migration where NUMA nodes match the destination

>Isn't pinning memory to all NUMA nodes equivalent to no pinning at all?
I  would use 'interlaeve' to let virtual machine's memory distribute evenly in all nodes. And
'interleave' setting ask for providing  'nodeset'. I think it is not so convenient.
>Michal