Re: [Qemu-devel] [PATCH v6 06/10] migration: move only_migratable to MigrationState

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, Jun 28, 2017 at 02:54:34PM +0800, Peter Xu wrote:
> On Tue, Jun 27, 2017 at 10:36:44AM -0300, Eduardo Habkost wrote:
> > On Tue, Jun 27, 2017 at 06:15:37AM -0500, Eric Blake wrote:
> > > On 06/26/2017 11:10 PM, Peter Xu wrote:
> > > > One less global variable, and it does only matter with migration.
> > > > 
> > > > We keep the old "--only-migratable" option, but also now we support:
> > > > 
> > > >   -global migration.only-migratable=true
> > > 
> > > Does command line introspection work to see that this new spelling is
> > > available?  If not, what else can we do to let libvirt learn that the
> > > new form is preferred?
> > 
> > "only-migratable" will appear on the output of
> > "device-list-properties typename=migration".  But although I think
> > implementing this using global properties internally is nice, I'm unsure
> > about making -global the recommended interface to configure this.
> 
> Could I ask why it may not good to use "-global" to configure it?
> 
> Actually if we can merge this series, there is planned work to expose
> more migration parameters to the user, like: migration.postcopy,
> migration.compression, migration.speed, etc. So before I post similar
> patches like this to export more things, I would like to know whether
> there is possible issue with it in general.  Thanks,

I don't see any obvious issue with "-global migration.FOO=BAR", but I
just want to be 100% sure before making it the recommended interface to
configure migration options.  If there are no objections, I'm OK with
that.

-- 
Eduardo