在 Ubuntu 服务器上运行的 CentOS 7 VM 正在消耗内存：
主持人：
# free -m
total used free shared buff/cache available
Mem: 80140 71676 5346 7 3117 7655
Swap: 4095 265 3830
# ps_mem
Private + Shared = RAM used Program
59.7 MiB + 67.4 MiB = 127.1 MiB fail2ban-server (4)
189.2 MiB + 189.6 MiB = 378.8 MiB mysqld
202.2 MiB + 206.9 MiB = 409.1 MiB lxd (5)
128.5 MiB + 558.5 MiB = 687.0 MiB systemd-journald (5)
30.1 GiB + 30.3 GiB = 60.4 GiB qemu-system-x86_64
---------------------------------
62.8 GiB
=================================
# virsh dommemstat ispmanager-master
actual 33554432
swap_in 1214268
swap_out 6718144
major_fault 429115
minor_fault 27183560666
unused 569424
available 32779288
usable 19841256
last_update 1597820230
rss 33239928
客人：
# free -m
total used free shared buff/cache available
Mem: 32011 11235 548 978 20226 19403
Swap: 10235 2568 7667
# lsmod | grep virt
virtio_balloon 18015 0
virtio_net 28114 0
net_failover 18147 1 virtio_net
virtio_blk 18323 4
virtio_console 28076 1
virtio_pci 22985 0
virtio_ring 22952 5 virtio_blk,virtio_net,virtio_pci,virtio_balloon,virtio_console
virtio 14959 5 virtio_blk,virtio_net,virtio_pci,virtio_balloon,virtio_consol
# virsh dommemstat ispmanager-master
actual 33554432
swap_in 0
swap_out 168
major_fault 24275
minor_fault 796131035
unused 395204
available 32779288
usable 25097908
last_update 1597885620
rss 33535884
来宾配置：
<domain type="kvm">
<name>ispmanager-master</name>
<uuid>353f2014-53d7-413e-b635-60eb4e78751b</uuid>
<metadata>
<libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
<libosinfo:os id="http://centos.org/centos/7.0"/>
</libosinfo:libosinfo>
</metadata>
<memory unit="KiB">33554432</memory>
<currentMemory unit="KiB">33554432</currentMemory>
<vcpu placement="static">10</vcpu>
<os>
<type arch="x86_64" machine="pc-i440fx-bionic">hvm</type>
</os>
<features>
<acpi/>
<apic/>
<vmport state="off"/>
</features>
<cpu mode="custom" match="exact" check="partial">
<model fallback="allow">Skylake-Server-IBRS</model>
</cpu>
<clock offset="utc">
<timer name="rtc" tickpolicy="catchup"/>
<timer name="pit" tickpolicy="delay"/>
<timer name="hpet" present="no"/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<pm>
<suspend-to-mem enabled="no"/>
<suspend-to-disk enabled="no"/>
</pm>
<devices>
<emulator>/usr/bin/kvm-spice</emulator>
<disk type="block" device="disk">
<driver name="qemu" type="raw" cache="none" io="native"/>
<source dev="/dev/zvol/pool1/vm/isp-master"/>
<target dev="vda" bus="virtio"/>
<boot order="1"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x07" function="0x0"/>
</disk>
<disk type="block" device="disk">
<driver name="qemu" type="raw" cache="none" io="native"/>
<source dev="/dev/zvol/pool1/vm/isp-master-backups"/>
<target dev="vdb" bus="virtio"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x09" function="0x0"/>
</disk>
<disk type="block" device="disk">
<driver name="qemu" type="raw" cache="none" io="native"/>
<source dev="/dev/zvol/ssd1/vm/isp-master"/>
<target dev="vdc" bus="virtio"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x0a" function="0x0"/>
</disk>
<disk type="file" device="cdrom">
<driver name="qemu" type="raw"/>
<target dev="hda" bus="ide"/>
<readonly/>
<address type="drive" controller="0" bus="0" target="0" unit="0"/>
</disk>
<controller type="usb" index="0" model="ich9-ehci1">
<address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x7"/>
</controller>
<controller type="usb" index="0" model="ich9-uhci1">
<master startport="0"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0" multifunction="on"/>
</controller>
<controller type="usb" index="0" model="ich9-uhci2">
<master startport="2"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x1"/>
</controller>
<controller type="usb" index="0" model="ich9-uhci3">
<master startport="4"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x2"/>
</controller>
<controller type="pci" index="0" model="pci-root"/>
<controller type="ide" index="0">
<address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x1"/>
</controller>
<controller type="virtio-serial" index="0">
<address type="pci" domain="0x0000" bus="0x00" slot="0x06" function="0x0"/>
</controller>
<interface type="bridge">
<mac address="52:54:00:83:c1:a8"/>
<source bridge="br0"/>
<model type="virtio"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x0"/>
</interface>
<serial type="pty">
<target type="isa-serial" port="0">
<model name="isa-serial"/>
</target>
</serial>
<console type="pty">
<target type="serial" port="0"/>
</console>
<channel type="unix">
<target type="virtio" name="org.qemu.guest_agent.0"/>
<address type="virtio-serial" controller="0" bus="0" port="1"/>
</channel>
<channel type="spicevmc">
<target type="virtio" name="com.redhat.spice.0"/>
<address type="virtio-serial" controller="0" bus="0" port="2"/>
</channel>
<input type="tablet" bus="usb">
<address type="usb" bus="0" port="1"/>
</input>
<input type="mouse" bus="ps2"/>
<input type="keyboard" bus="ps2"/>
<graphics type="spice" autoport="yes">
<listen type="address"/>
</graphics>
<video>
<model type="qxl" ram="65536" vram="65536" vgamem="16384" heads="1" primary="yes"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0"/>
</video>
<redirdev bus="usb" type="spicevmc">
<address type="usb" bus="0" port="2"/>
</redirdev>
<redirdev bus="usb" type="spicevmc">
<address type="usb" bus="0" port="3"/>
</redirdev>
<memballoon model="virtio">
<address type="pci" domain="0x0000" bus="0x00" slot="0x08" function="0x0"/>
</memballoon>
</devices>
</domain>
出了什么问题？我该如何解决？