Ubuntu
qemu package

  1. Bug #503138
  2. Comment #24

Comment 24 for bug 503138

Revision history for this message
Arie Skliarouk (skliarie) wrote :

This happened because guest used lots of memory on NUMA machine. The KSM might merge similar memory pages of different VMs, sitting on different NUMA memory regions, causing the affected processes to crawl.

Disabled KSM merge_across_nodes:

echo 2 > /sys/kernel/mm/ksm/run && sleep 300 && cat /sys/kernel/mm/ksm/pages_shared
If there are no pages shared :

echo 0 > /sys/kernel/mm/ksm/merge_across_nodes && echo 1 > /sys/kernel/mm/ksm/run
make sure to set merge_across_nodes in /etc/sysctl.d to stay across reboots.