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

[Luiz Capitulino]

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.

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