Re: [libvirt-users] what is the xml fomat about memory-backend-file
On 2014/9/25 2:05, Eric Blake wrote:
On 09/24/2014 02:05 AM, Linhaifeng wrote:
> Hi,
>
> I want to use virsh to create a VM with the qemu parameter '-object
memory-backend-file,id=mem,size=2048M,mem-path=/mnt/huge,share=on -numa
node,memdev=mem'.
Looking at tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages.args, I
see several instances of "-object memory-backend-file...", so look at
the counterpart .xml file for some examples:
<memoryBacking>
<hugepages>
<page size='2048' unit='KiB' nodeset='1'/>
<page size='1048576' unit='KiB' nodeset='0,2-3'/>
</hugepages>
</memoryBacking>
Thank you.
I use this xml:
<cpu>
<numa>
<cell id='0' cpus='0' memory='1073741824'
memAccess='shared'/>
<cell id='1' cpus='1' memory='1073741824'
memAccess='shared'/>
</numa>
</cpu>
<memoryBacking>
<hugepages>
<page size="2" unit="M" nodeset="0,1"/>
</hugepages>
</memoryBacking>
but there is also some error:
[2014-09-28T05:28:32.373335Z] migration_configure:652 Parameter 'cache size'
expects exceeds guest ram size
[2014-09-28T05:28:32.373422Z] main:3517 start memory options parse
2014-09-28T05:28:32.373802Z qemu-kvm: -object
memory-backend-file,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,size=1048576M,id=ram-node0:
unable to map backing store for hugepages: Cannot allocate memory
2014-09-28T05:28:32.373895Z qemu-kvm: -object
memory-backend-file,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,size=1048576M,id=ram-node1:
unable to map backing store for hugepages: Cannot allocate memory