[libvirt] [PATCH v1 5/7] domain: Introduce ./hugepages/page/[@size, @unit, @nodeset]

[Michal Privoznik]

On 21.07.2014 17:09, Daniel P. Berrange wrote:
> On Thu, Jul 17, 2014 at 06:12:46PM +0200, Michal Privoznik wrote:
>> +<domain type='qemu'>
>> +  <name>QEMUGuest1</name>
>> +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
>> +  <memory unit='KiB'>4194304</memory>
>> +  <currentMemory unit='KiB'>4194304</currentMemory>
>> +  <memoryBacking>
>> +    <hugepages>
>> +      <page size='2048' unit='KiB' nodeset='1'/>
>> +      <page size='1048576' unit='KiB' nodeset='0,2-3'/>
>> +    </hugepages>
>> +  </memoryBacking>
>> +  <vcpu placement='static'>4</vcpu>
>> +  <numatune>
>> +    <memory mode='strict' nodeset='0-3'/>
>> +    <memnode cellid='3' mode='strict' nodeset='3'/>
>> +  </numatune>
>> +  <os>
>> +    <type arch='i686' machine='pc'>hvm</type>
>> +    <boot dev='hd'/>
>> +  </os>
>> +  <cpu>
>> +    <numa>
>> +      <cell id='0' cpus='0' memory='1048576'/>
>> +      <cell id='1' cpus='1' memory='1048576'/>
>> +      <cell id='2' cpus='2' memory='1048576'/>
>> +      <cell id='3' cpus='3' memory='1048576'/>
>> +    </numa>
>> +  </cpu>
>
> There's nothing functionally wrong with what you have here, but I'm
> wondering if you considered just adding a page size attribute against
> the <cell> element under <numa> here ? Feels like that might be a bit
> less verbose for the XML

Huh funny. That idea came up to my mind, but I thought it was more 
verbose so I went down this road. I'm not fundamentally against it, but 
I like my approach more. In most common case, users will use only one 
size of huge pages to back their guests, so all they need to do is:

<memoryBacking>
   <hugepages>
     <page size='1' unit='G'/>
   </hugepages>
</memoryBacking>

instead of repeating @pagesize attribute in each <cell/>. But as far as 
I see it's just question of preference without any technical impact, right?

Michal