On Thu, Jun 11, 2015 at 10:27:05AM +0200, Michal Privoznik wrote: > On 11.06.2015 10:13, Daniel P. Berrange wrote: > > On Wed, Jun 10, 2015 at 09:20:40PM +0000, Vivi L wrote: > >> Michal Privoznik <mprivozn <at> redhat.com> writes: > >> > >>> > >>> On 10.06.2015 01:05, Vivi L wrote: > >>>> Kashyap Chamarthy <kchamart <at> redhat.com> writes: > >>>> > >>>> > >>>>> You might want re-test by explicitly setting the 'page' element and > >>>>> 'size' attribute? From my test, I had something like this: > >>>>> > >>>>> $ virsh dumpxml f21-vm | grep hugepages -B3 -A2 > >>>>> <memory unit='KiB'>2000896</memory> > >>>>> <currentMemory unit='KiB'>2000000</currentMemory> > >>>>> <memoryBacking> > >>>>> <hugepages> > >>>>> <page size='2048' unit='KiB' nodeset='0'/> > >>>>> </hugepages> > >>>>> </memoryBacking> > >>>>> <vcpu placement='static'>8</vcpu> > >>>>> > >>>>> I haven't tested this exhaustively, but some basic test notes here: > >>>>> > >>>>> https://kashyapc.fedorapeople.org/virt/test-hugepages-with-libvirt.txt > >>>> > >>>> Current QEMU does not support setting <page> element. Could it be the > >>>> cause of my aforementioned problem? > >>>> > >>>> unsupported configuration: huge pages per NUMA node are not supported > >>>> with this QEMU > >>>> > >>> > >>> So this is explanation why the memory for you guest is not backed by > >>> hugepages. > >> > >> I thought setting hugepages per NUMA node is a nice-to-have feature. > >> Is it required to enable the use of hugepages for the guest? > > > > No, it should not be mandatory. You should be able to use > > > > <memoryBacking> > > <hugepages/> > > </memoryBacking> > > > > With pretty much any KVM/QEMU version that exists. If that's > > broken then its a libvit bug. > > Unless hugepages are requested for guest NUMA nodes. In that case > memory-backend-file object is required. From my investigation, this > seems to be the case. memory-backend-file should only be required if trying to setup different hugepage configs for each guest NUMA node, or if trying to pin each guest NUMA node to a different host node. If they just want hugepages across the whole VM and no pinning shouldn't the traditional setup work Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list