[libvirt] [PATCH RFC 2/3] conf: ABI: Memballoon setting is not guest ABI

[Daniel P. Berrange]

On Mon, Feb 16, 2015 at 08:50:43PM +0100, Peter Krempa wrote:
> The current balloon setting does not influence the ABI of the guest and
> the driver should take the change just fine.
> ---
> I personally don't think that this check is useful, but I'll happily drop the
> patch if anybody thinks otherwise.
> 
>  src/conf/domain_conf.c | 6 ------
>  1 file changed, 6 deletions(-)

Yes, you can change the balloon target on the fly, so this isn't something
we need to keep as stable across migration. The question though is whether
libvirt/QEMU will correctly handle the changed balloon setting during
migration. ie does libvirt correctly issue a 'balloon' monitor command on
the target host if it has changed in the target XML ?  If it does, then I
agree this check can go..

> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 9a7060d..eee01b6 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -15963,12 +15963,6 @@ virDomainDefCheckABIStability(virDomainDefPtr src,
>                         dst->mem.max_balloon, src->mem.max_balloon);
>          goto error;
>      }
> -    if (src->mem.cur_balloon != dst->mem.cur_balloon) {
> -        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> -                       _("Target domain current memory %lld does not match source %lld"),
> -                       dst->mem.cur_balloon, src->mem.cur_balloon);
> -        goto error;
> -    }


Regards,
Daniel
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