Configure hugepages and then start virtual guest via "virsh start". However,
virtual guest failed to use hugepages although it's configured
The initial usage of system memory
[root@local ~]# free
total used free shared buff/cache available
Mem: 263767352 1900628 261177892 9344 688832 261431872
Swap: 4194300 0 4194300
After configuring hugepages,
[root@local ~]# cat /proc/meminfo | grep uge
AnonHugePages: 2048 kB
HugePages_Total: 140
HugePages_Free: 140
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 1048576 kB
[root@local ~]# mount | grep huge
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,
relatime,hugetlb)hugetlbfs on /dev/hugepages type hugetlbfs (rw,realtime)
On the guest side, its config xml contains
<domain type='kvm'>
<name>test-01</name>
<uuid>e1b72349-4a0b-4b91-aedc-fd34e92251e4</uuid>
<description>test-01</description>
<memory unit='KiB'>134217728</memory>
<currentMemory unit='KiB'>134217728</currentMemory>
<memoryBacking>
<hugepages/>
<nosharepages/>
</memoryBacking>
Tried to virsh start the guest, but it failed although the hugepages memory
was sufficient
virsh # start test-01
error: Failed to start domain test-01
error: internal error: early end of file from monitor: possible problem:
Cannot set up guest memory 'pc.ram': Cannot allocate memory
however, if decrease the number of hugepages to smaller(say 100) that
makes the memory not used by hugepages more than required by guest,
then guest can start. But memory is not allocated from hugepages.
[root@local ~]# cat /proc/meminfo | grep uge
AnonHugePages: 134254592 kB
HugePages_Total: 100
HugePages_Free: 100
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 1048576 kB
In summary, although hugepages is configured, the guest seemed not
instructed to use hugepage, instead, the guest is allocated memory from
the memory pool leftover by hugepages.
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list