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?
Can you please share the qemu command line that libvirt generated for your guest?
If setting 100 hugepages, the guest can start while not using hugepages at all. In this case, [root@local ~]# ps -ef | grep qemu qemu 3403 1 99 17:42 ? 00:36:42 /usr/libexec/qemu-kvm -name qvpc-di-03-sf -S -machine pc-i440fx-rhel7.0.0,accel=kvm,usb=off -cpu host -m 131072 -realtime mlock=off -smp 32,sockets=2,cores=16,threads=1 -numa node,nodeid=0,cpus=0-15,mem=65536 -numa node,nodeid=1, cpus=16-31,mem=65536 -uuid e1b72349-4a0b-4b91-aedc-fd34e92251e4 - smbios type=1,serial=SCALE-SLOT-03 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/qvpc-di-03-sf.monitor,server, nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0, addr=0x1.0x2 -drive file=/var/lib/libvirt/images/asr5700/qvpc-di-03-sf- hda.img,if=none,id=drive-ide0-0-0,format=qcow2 -device ide- hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=2 -drive if=none,id=drive-ide0-1-0,readonly=on,format=raw -device ide- cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=1 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev pty,id=charserial1 -device isa-serial,chardev=charserial1,id=serial1 -vnc 127.0.0.1:0 -vga cirrus -device i6300esb,id=watchdog0,bus=pci.0, addr=0x3 -watchdog-action reset -device vfio-pci,host=08:00.0,id=hostdev0,bus=pci.0,addr=0x5 -device vfio- pci,host=09:00.0,id=hostdev1,bus=pci.0,addr=0x6 -device vfio- pci,host=0a:00.0,id=hostdev2,bus=pci.0,addr=0x7 -device virtio-balloon- pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on
Michal