[libvirt-users] is memoryBacking support 'share' and 'mem-path' parameter

[Martin Kletzander]

On Thu, Oct 09, 2014 at 09:54:44AM +0800, Linhaifeng wrote:
>
>
>On 2014/10/8 16:57, Martin Kletzander wrote:
>> On Wed, Oct 08, 2014 at 10:03:47AM +0800, Linhaifeng wrote:
>>> Hi,
>>>
>>> I want to use this qemu command '-object memory-backend-file,id=mem,size=2048M,mem-path=/mnt/huge,share=on' with libvirt but i can't find the 'mem-path' and 'share' in the documentation.
>>> because the vhost-user backend based on 'share=on' parameter and libvirt support vhostuser i guess there maybe another way to support this parameter?
>>>
>>> this is my xml:
>>>  <cpu>
>>>    <numa>
>>>      <cell id='0' cpus='0' memory='1048576' memAccess='shared'/>
>>>      <cell id='1' cpus='1' memory='1048576' memAccess='shared'/>
>>
>> this memAccess='shared' is exactly what you need in order for the
>> share='on' to be appended.  I wonder why it's not there.  What libvirt
>> version are you using?
>
>-bash-4.2# virsh --version
>1.2.7
>

Well, the code was added by commits starting from
def6b35989362cc7ce8474256e19d877ff07a711, described as
v1.2.8-168-gdef6b35, i.e. 128 commits *after* 1.2.8 release, so the
code is in 1.2.9.  Unless you are using some custom build with those
patches back-ported, it's not going to work.  You can try dumping XML
of the machine after it has been defined/created and if that
attributes are not kept in the XML then there's no support for it.

Martin

>
>>
>>>    </numa>
>>>  </cpu>
>>> <memoryBacking>
>>>    <hugepages>
>>>      <page size="2" unit="M" nodeset="0,1"/>
>>>    </hugepages>
>>>    <!--nosharepages/-->
>>>    <!--locked/-->
>>> </memoryBacking>
>>>
>>>
>>>    <interface type='vhostuser'>
>>>      <mac address='52:54:00:3b:83:1a'/>
>>>      <source type='unix' path='/path/port1' mode='client'/>
>>>      <model type='virtio'/>
>>>    </interface>
>>>    <interface type='vhostuser'>
>>>      <mac address='52:54:00:3b:83:1b'/>
>>>      <source type='unix' path='/path/port2' mode='client'/>
>>>      <model type='virtio'/>
>>>    </interface>
>>>
>>>
>>> when i create the VM the qemu command is like this without 'share=on' parameter:
>>> -object memory-backend-file,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,size=1024M,id=ram-node0 -numa node,nodeid=0,cpus=0,memdev=ram-node0
>>> -object memory-backend-file,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,size=1024M,id=ram-node1 -numa node,nodeid=1,cpus=1,memdev=ram-node1
>>>
>>> _______________________________________________
>>> libvirt-users mailing list
>>> libvirt-users at redhat.com
>>> https://www.redhat.com/mailman/listinfo/libvirt-users
>
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