[openstack-dev] [nova] NUMA, huge pages, and scheduling

Chris Friesen chris.friesen at windriver.com
Thu Jun 9 03:19:31 UTC 2016


On 06/03/2016 12:03 PM, Paul Michali wrote:
> Thanks for the link Tim!
>
> Right now, I have two things I'm unsure about...
>
> One is that I had 1945 huge pages left (of size 2048k) and tried to create a VM
> with a small flavor (2GB), which should need 1024 pages, but Nova indicated that
> it wasn't able to find a host (and QEMU reported an allocation issue).
>
> The other is that VMs are not being evenly distributed on my two NUMA nodes, and
> instead, are getting created all on one NUMA node. Not sure if that is expected
> (and setting mem_page_size to 2048 is the proper way).


Just in case you haven't figured out the problem...

Have you checked the per-host-numa-node 2MB huge page availability on your host? 
  If it's uneven then that might explain what you're seeing.

Chris



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