[libvirt PATCH 15/17] qemu: Add external_limit_manager config knob

[Andrea Bolognani]

On Mon, 2021-03-08 at 10:52 +0000, Daniel P. Berrangé wrote:
> On Fri, Mar 05, 2021 at 08:14:02PM +0100, Andrea Bolognani wrote:
> > +# If enabled, libvirt will not attempt to change process limits (as
> > +# configured with the max_processes, max_files and max_core settings
> > +# below) itself but will instead expect an external entity to perform
> > +# this task.
> 
> Can't users simply not set max_core, max_files, etc already ?

That works for things that are static and have a corresponding
configuration option in qemu.conf, but the memory locking limit is
dynamic, per-VM and needs to change as devices are added and removed
from the guest.

> I think it is preferrable to have flags tailored specifically to
> the individual limits, not a global flag. Otherwise you can end
> up in a case where you want to disable the memory limits, but
> keep the other limits set which is impossible with this global
> flag.

Since what I'm interested in is the memory locking limit, I guess I
could turn this into

  max_memlock_external = 1

or even

  max_memlock = "external"

with "dynamic" being the other accepted value, which would be the
default and would behave as libvirt does today.

Do you think that would work better?

-- 
Andrea Bolognani / Red Hat / Virtualization