Re: [Qemu-devel] [RFC 3/3] memory/qmp: add set-memory-merge command

[Daniel P. Berrange]

On Tue, Jun 26, 2012 at 09:53:32AM -0300, Luiz Capitulino wrote:
> On Tue, 26 Jun 2012 10:25:22 +0100
> "Daniel P. Berrange" <address@hidden> wrote:
> 
> > On Mon, Jun 25, 2012 at 05:05:45PM -0500, Anthony Liguori wrote:
> > > On 06/25/2012 11:55 AM, Luiz Capitulino wrote:
> > > >Allow to enable/disable memory merging during run-time.
> > > >
> > > >This is implemented by extending the qemu_set_mem_merge() function.
> > > >
> > > >To test on HMP:
> > > >
> > > >   (qemu) set_memory_merge on
> > > >   (qemu) set_memory_merge off
> > > >
> > > >Signed-off-by: Luiz Capitulino<address@hidden>
> > > 
> > > Is there a requirement to tweak KSM dynamically on a per-VM basis or
> > > was this just a nice to have?
> > > 
> > > I can certainly understand wanting to run your VMs without KSM but
> > > not wanting to have to muck with global configuration values.
> > > 
> > > I would suspect that people would either overcommit or not
> > > overcommit as a global decision.  Once you overcommit even one
> > > machine, you potentially put your whole system in danger of swap.
> > 
> > I tend to agree, this monitor commands feels like a feature without a
> > clear usecase.
> 
> Well, the request for it came from libvirt and I implemented it without
> wondering much about it.

Hmm, I think that must have been a mis-understanding soemwhere, because
I'm not aware of having asked for a monitor command! All we desire for
libvirt is for the custom command line argument hack that was done in
RHEL KVM trees, to be turned into a upstream accepted command line arg.

> But if you think it's not worth it, I'll just drop it.

Sounds good :-)

Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|