Re: [Qemu-devel] [RFC PATCH RDMA support v1: 10/13] introduce new command migrate_check_for_zero

[Michael R. Hines]

On 04/11/2013 09:51 AM, Michael S. Tsirkin wrote:
> On Thu, Apr 11, 2013 at 09:19:43AM -0400, Michael R. Hines wrote:
> > On 04/11/2013 07:13 AM, Michael S. Tsirkin wrote:
> > > On Thu, Apr 11, 2013 at 11:18:38AM +0200, Paolo Bonzini wrote:
> > > > Il 11/04/2013 09:38, Michael S. Tsirkin ha scritto:
> > > > > On Wed, Apr 10, 2013 at 06:28:18PM -0400, address@hidden wrote:
> > > > > > From: "Michael R. Hines" <address@hidden>
> > > > > >
> > > > > > This allows the user to disable zero page checking during migration
> > > > > >
> > > > > > Signed-off-by: Michael R. Hines <address@hidden>
> > > > > IMO this knob is too low level to expose to management.
> > > > > Why not disable this automatically when migrating with rdma?
> > > > Thinking more about it, I'm not sure why it is important to disable it.
> > > This just illustrates the point. There's no place for such low level
> > > knobs in the management interface.
> > I disagree with that: We already have precedent for this in the
> > XBZRLE capability.
> My understanding is the issue is protocol compatibility,
> not optimization. E.g. you can migrate to file, for each
> new feature you need a way to disable it to stay compatible.

Ok, understood.

I would be happy to add a check for the other migration URI
protocols (like 'unix', 'tcp', etc) which says rejects disabling
the zero page checking only if the URI is for rdma.

Would that be OK?