Public bug reported:
[Environment]
root@buneary:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.2 LTS
Release: 16.04
Codename: xenial
root@buneary:~# uname -r
4.10.0-29-generic
Reproducible also with the 4.4 kernel.
[Description]
When a guest memory backing stanza is defined using the <locked/> stanza +
hugepages,
as follows:
<memoryBacking>
<hugepages>
<page size='1' unit='GiB' nodeset='0'/>
<page size='1' unit='GiB' nodeset='1'/>
</hugepages>
<nosharedpages/>
<locked/>
</memoryBacking>
(Full guest definition: http://paste.ubuntu.com/25229162/)
The guest fails to start due to the following error:
2017-08-02 20:25:03.714+0000: starting up libvirt version: 1.3.1, package:
1ubuntu10.12 (Christian Ehrhardt <christian.ehrha...@canonical.com> Wed, 19 Jul
2017 08:28:14 +0200), qemu version: 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.14),
hostname: buneary.seg
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
QEMU_AUDIO_DRV=none /usr/bin/kvm-spice -name reproducer2 -S -machine
pc-i440fx-2.5,accel=kvm,usb=off -cpu host -m 124928 -realtime mlock=on -smp
32,sockets=16,cores=1,threads=2 -object
memory-backend-file,id=ram-node0,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,share=yes,size=64424509440,host-nodes=0,policy=bind
-numa node,nodeid=0,cpus=0-15,memdev=ram-node0 -object
memory-backend-file,id=ram-node1,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu,share=yes,size=66571993088,host-nodes=1,policy=bind
-numa node,nodeid=1,cpus=16-31,memdev=ram-node1 -uuid
2460778d-979b-4024-9a13-0c3ca04b18ec -no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-reproducer2/monitor.sock,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/uvtool/libvirt/images/te
st-ds.qcow,format=qcow2,if=none,id=drive-virtio-disk0,cache=none -device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
-chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0
-vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on
Domain id=14 is tainted: host-cpu
char device redirected to /dev/pts/1 (label charserial0)
mlockall: Cannot allocate memory
2017-08-02T20:25:37.732772Z qemu-system-x86_64: locking memory failed
2017-08-02 20:25:37.811+0000: shutting down
This seems to be due to the setrlimit for RLIMIT_MEMLOCK is too low for
mlockall
to work given the large amount of memory.
There is a libvirt upstream patch that enforces the existence of the
hard_limit stanza when using with <locked/> in the memory backing settings.
https://github.com/libvirt/libvirt/commit/c2e60ad0e5124482942164e5fec088157f5e716a
Memory locking can only work properly if the memory locking limit
for the QEMU process has been raised appropriately: the default one
is extremely low, so there's no way the guest will fit in there.
[Suggested Fix]
*
https://github.com/libvirt/libvirt/commit/c2e60ad0e5124482942164e5fec088157f5e716a
** Affects: libvirt (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1708305
Title:
Realtime feature mlockall: Cannot allocate memory
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