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linux package

  1. Bug #1413540
  2. Comment #5

Comment 5 for bug 1413540

Revision history for this message
Serge Hallyn (serge-hallyn) wrote : Re: qemu-kvm package enables KSM on VMs

A few comments here.

First, some of upstream qemu's position is that nested KVM is not for enterprise installs in the first place. (Others feel that if there are bugs, they should be worked out)

Second, the bug appears to be a soft luckup. It seems to me the bug should be about that. If you've opened a separate bug about the lockup itself, please mark it both against qemu and linux. If not, then let's mark this bug as also affecting linux.

Thirdly, there's the question of how to (assuming we decide to) implement this. Should /etc/init/qemu-kvm do something like

   grep -qi qemu /proc/cpuinfo && echo 0 > /sys/kernel/mm/ksm/run

?

Note that you can currently do this yourself by having your VM install (say at cloud-init or in juju install section) set KSM_ENABLED=0 in /etc/default/qemu-kvm

I'm not sure how to mark the priroity of this bug. If the bug is about the soft lockup, that's high priority (against linux). if it's about disabling ksm, that's low priority (against qemu, since there's a workaround)