Regarding fine tuning my explanation about what system does de actual mounting of
Hugepages, you’re probably right…. Thanks for the correction.
On upstart systems (like Ubuntu) the mounting of Hugepages is done by the init script
qemu-kvm.conf
Van: G. Richard Bellamy [mailto:rbellamy@pteradigm.com]
Verzonden: zondag 1 februari 2015 0:02
Aan: Dominique Ramaekers
CC: libvirt-users(a)redhat.com
Onderwerp: Re: [libvirt-users] HugePages - can't start guest that requires them
Yeah, Dominique, your wiki was one of the many docs I read through before/during/after
starting down this primrose path... thanks for writing it. I'm an Arch user, and I
couldn't find anything to indicate qemu, as its compiled for Arch, will look in
/etc/default/qemu-kvm. And now that I've got the right page size, the instances are
starting...
The reason I want to use the page element to the hugepages directive is that I want to
target a numa node directly - in other words, I like the idea of one VM running on Node 0,
and the other running on Node 2.
Your comment about libvirt taking care of the hugepages mount isn't consistent with my
reading or experience - on a systemd-based system, systemd takes care of the hugetlbfs
mount to /dev/hugepages, and the libvirt builds the /dev/hugepages/qemu... directory
structure. At least that's what I've seen.
-rb
On Sat, Jan 31, 2015 at 11:43 AM, Dominique Ramaekers
<dominique.ramaekers@cometal.be<mailto:dominique.ramaekers@cometal.be>>
wrote:
Did you create a mount for the hugepages? If you did, that's maybe the problem. I did
that also at first but with libvirt it isn't necessary and in my case, it broke
hugepages...
If I'm not mistaking, libvirt takes care of the hugepages mount.
A while ago, I've written a wiki to use hugepages in libvirt and Ubuntu.
https://help.ubuntu.com/community/KVM%20-%20Using%20Hugepages
Maybe this helps?
________________________________________
Van: G. Richard Bellamy [rbellamy@pteradigm.com<mailto:rbellamy@pteradigm.com>]
Verzonden: zaterdag 31 januari 2015 0:33
Aan: libvirt-users@redhat.com<mailto:libvirt-users@redhat.com>
Onderwerp: [libvirt-users] HugePages - can't start guest that requires them
Hello All,
I'm trying to enable hugepages, I've turned off THP (Transparent Huge
Pages), and enabled hugepages in memoryBacking, and set my 2MB
hugepages count via sysctl.
I'm getting "libvirtd[5788]: Failed to autostart VM 'atlas': internal
error: Unable to find any usable hugetlbfs mount for 16777216 KiB"
where atlas is one of my guests and 16777216 KiB is the amount of
memory I'm trying to give to the guest.
Yes, i can see the hugepages via numastat -m and hugetlbfs is mounted
via /dev/hugepages and there is a dir structure
/dev/hugepages/libvirt/qemu (it's empty).
HugePages is big enough to accommodate the 16G i'm allocating... and
changing the perms on that directory structure to 777 doesn't work
either.
Any help is much appreciated.
HOST:
http://sprunge.us/SEdc
GUEST:
http://sprunge.us/VCYB
Regards,
Richard
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