Re: [Qemu-devel] [PATCH v2 1/3] pc-dimm: add a function to calculate VM's current RAM size

[Michael S. Tsirkin]

On Wed, Nov 19, 2014 at 08:52:19AM -0700, Eric Blake wrote:
> On 11/19/2014 08:13 AM, Luiz Capitulino wrote:
> > On Wed, 19 Nov 2014 12:32:46 +0200
> > "Michael S. Tsirkin" <address@hidden> wrote:
> > 
> >> On Mon, Nov 17, 2014 at 01:11:08PM +0800, zhanghailiang wrote:
> >>> The global parameter 'ram_size' does not take into account
> >>> the hotplugged memory.
> >>>
> >>> In some codes, we use 'ram_size' as current VM's real RAM size,
> >>> which is not correct.
> >>>
> >>> Add function 'get_current_ram_size' to calculate VM's current RAM size,
> >>> it will enumerate present memory devices and also plus ram_size.
> >>>
> >>> Signed-off-by: zhanghailiang <address@hidden>
> >>
> >>
> >> This affects QMP right?
> > 
> > I think later patches will tell how. CC'ing Eric.
> 
> As far as I can tell, this is just correcting a reporting issue; the
> existing QMP commands/events for tracking balloon size will now properly
> account for hotplugged memory.
> 
> What I don't know is if this change in semantics will affect any users.
>  Libvirt is not yet supporting memory hotplug, so ideally, fixing this
> bug before libvirt uses memory hotplug means libvirt will never have to
> worry about qemu versions that do incorrect reporting.
> 
> The alternative is to declare that the existing QMP commands cannot
> change in semantics for the existing members that it reports, and must
> instead report additional dictionary members describing the amount of
> hot-plugged memory, and then require that the client add the numbers
> together itself.  That sounds mean to the client, so I'm hoping we don't
> have to go there.


IOW you ack this patch for 2.2?