Re: [Qemu-devel] Tracking hugepages usage

[Vladyslav Drok]

On Thu, Jun 1, 2017 at 1:56 PM, Andrey Korolyov <address@hidden> wrote:

> On Thu, Jun 1, 2017 at 1:38 PM, Vladyslav Drok <address@hidden> wrote:
> > Hello qemu community!
> >
> > I come from openstack world, and one of our customers complains about an
> > issue with huge pages on compute nodes. From the "virsh frepages --all"
> and
> > "cat /proc/meminfo", they see that 4 huge pages are consumed:
> >
> > http://paste.openstack.org/show/611186/
> >
> > In total there are 239 1G pages, 120 in numa node 0, and 119 in numa node
> > 1. There are no VMs running at this point.
> >
> > When trying to find out what consumes the 4 1G huge pages from node 0, I
> > was suggesting "grep 1048576 /proc/*/numa_maps" to find out which
> processes
> > are using 1G pages, but in this particular case it shows no processes.
> > While when some VM is running, I can see the qemu process that's
> consuming
> > huge pages, numa_maps reports the correct amount of pages, corresponding
> to
> > what has been requested for the VM's RAM.
> >
> > Are there any recommended ways for trying to track what consumes these 4
> > "lost" pages? (I might be a bit slow providing more info, as I don't have
> > access to this environment :( )
> >
> > Thanks,
> > Vlad
>
> Could you please try to walk against /proc/[0-9]/smaps to check that
> these pages are not claimed by any process?
>

Thanks for the suggestion! Will provide the results as soon as I have it.