重点部分

1、添加hugepages

  <memory unit='M'>4096</memory>
  <currentMemory unit='M'>4096</currentMemory>
  <memoryBacking>
    <hugepages>
      <page size="1" unit="G" nodeset="0"/>
    </hugepages>
    <source type="file"/>
    <access mode="private"/>
    <allocation mode="immediate"/>
  </memoryBacking>
  <cpu mode='host-model'>
    <model fallback='allow'/>
    <topology sockets='1' cores='4' threads='1'/>
    <numa>
      <cell id='0' cpus='0-3' memory='4096' unit='M' memAccess='shared'/>
    </numa>
  </cpu>

2、添加vhost接口，mode有server和client

    <interface type='vhostuser'>
      <mac address='fa:16:3e:66:bd:66'/>
      <source type='unix' path='/usr/local/var/run/openvswitch/vhost-user1' mode='client' />
      <model type='virtio'/>
    </interface>
    <interface type='vhostuser'>
      <mac address='fa:16:3e:66:bd:88'/>
      <source type='unix' path='/usr/local/var/run/openvswitch/vhost-user2' mode='client' />
      <model type='virtio'/>
    </interface>

在/etc/libvirt/qemu.conf添加

memory_backing_dir = "/mnt/huge"

4、完整XML文件

<domain type='kvm' id='93'>
  <name>instance-vhost</name>
  <uuid>5f98aaaa-0f1c-4660-ac93-c92ea4d46e91</uuid>
  <Metadata>
    <nova:instance xmlns:nova="http://openstack.org/xmlns/libvirt/nova/1.0">
      <nova:package version="2015.1.0-20161229.el7"/>
      <nova:name>VM_1482923074.24</nova:name>
      <nova:creationTime>2017-01-03 08:05:04</nova:creationTime>
      <nova:flavor name="FLV_1483411170.68">
        <nova:memory>8192</nova:memory>
        <nova:disk>50</nova:disk>
        <nova:swap>0</nova:swap>
        <nova:ephemeral>0</nova:ephemeral>
        <nova:vcpus>32</nova:vcpus>
      </nova:flavor>
      <nova:owner>
        <nova:user uuid="9a880356a66443049beb632bf6835ed3">jianghui522</nova:user>
        <nova:project uuid="d6aa39869a4843b2a70cf7e59b1d1076">jianghui522</nova:project>
      </nova:owner>
      <nova:root type="image" uuid="ba652e41-47d8-4820-a1b5-7024e70ac67c"/>
    </nova:instance>
  </Metadata>
  <memory unit='M'>4096</memory>
  <currentMemory unit='M'>4096</currentMemory>
  <memoryBacking>
    <hugepages>
      <page size="1" unit="G" nodeset="0"/>
    </hugepages>
    <source type="file"/>
    <access mode="private"/>
    <allocation mode="immediate"/>
  </memoryBacking>
  <cpu mode='host-model'>
    <model fallback='allow'/>
    <topology sockets='1' cores='4' threads='1'/>
    <numa>
      <cell id='0' cpus='0-3' memory='4096' unit='M' memAccess='shared'/>
    </numa>
  </cpu>
  <vcpu placement='static' current='4'>4</vcpu>
  <cputune>
    <shares>12288</shares>
  </cputune>
  <resource>
    <partition>/machine</partition>
  </resource>
    <sysinfo type='smbios'>
      <system>
        <entry name='manufacturer'>Fedora Project</entry>
        <entry name='product'>OpenStack Nova</entry>
        <entry name='version'>2015.1.0-20161229.el7</entry>
        <entry name='serial'>5a8f8f31-db9f-4b84-93bb-6f4837434eb9</entry>
        <entry name='uuid'>5f98aaaa-0f1c-4660-ac93-c92ea4d46e91</entry>
      </system>
    </sysinfo>
  <os>
    <type arch='x86_64' machine='pc-i440fx-1.6'>hvm</type>
    <boot dev='hd'/>
    <smbios mode='sysinfo'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state='on'/>
      <vapic state='on'/>
      <spinlocks state='on' retries='8191'/>
    </hyperv>
  </features>
  <clock offset='localtime'>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/home/vm/vm_licko/CENT_7.1_S_64_X_20_X_pktgen.qcow2'/>
      <backingStore/>
      <target dev='vda' bus='virtio'/>
      <serial>cafb3cff-8267-4a13-991b-c92103741992</serial>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </disk>
    <controller type='usb' index='0'>
      <alias name='usb0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'>
      <alias name='pci.0'/>
    </controller>
    <interface type='vhostuser'>
      <mac address='fa:16:3e:66:bd:66'/>
      <source type='unix' path='/usr/local/var/run/openvswitch/vhost-user1' mode='client' />
      <model type='virtio'/>
    </interface>
    <interface type='vhostuser'>
      <mac address='fa:16:3e:66:bd:88'/>
      <source type='unix' path='/usr/local/var/run/openvswitch/vhost-user2' mode='client' />
      <model type='virtio'/>
    </interface>
    <serial type='file'>
      <source path='/var/lib/nova/instances/5f98aaaa-0f1c-4660-ac93-c92ea4d46e91/console.log'/>
      <target port='0'/>
      <alias name='serial0'/>
    </serial>
    <serial type='pty'>
      <source path='/dev/pts/1'/>
      <target port='1'/>
      <alias name='serial1'/>
    </serial>
    
    <input type='tablet' bus='usb'>
      <alias name='input0'/>
    </input>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='vnc' port='5901' autoport='yes' listen='0.0.0.0' keymap='en-us'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <video>
      <model type='cirrus' vram='16384' heads='1'/>
      <alias name='video0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <alias name='balloon0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
      <stats period='10'/>
    </memballoon>
  </devices>
</domain>