Re: [libvirt] [RFC 12/42] pc: initialize legacy hotplug only for 2.6 and older machine types

On Thu, 12 May 2016 13:04:23 +0200 Peter Krempa <pkrempa(a)redhat.com&gt; wrote: > On Thu, May 12, 2016 at 07:52:23 -0300, Eduardo Habkost wrote: > > I don't think we should do that, unless users already had time to > > update their scripts and libvirt had time to implement code > > supporting the new method. > > > > I believe libvirt (and people's scripts) use maxcpus only when > > they want CPU hotplug, so making max_cpus > smp_cpus enable CPU > > hotplug implicitly would probably solve the compatibility issue. > > Libvirt uses maxcpus only if the configuration explicitly has less > active cpus than the maximum number. This option would be the best IMO. > > > If we want to deprecate the use of maxcpus to enable CPU hotplug, > > then we can make it print a warning for a few releases, so people > > have time to update their code. > > At that point libvirt also needs a way to detect that the new argument > is supported by qemu, so we can start passing it on the command line > basically every time we now pass 'maxcpus'. > > The warning will get most probably ignored by people using libvirt as > the stdout/err of qemu is not visible to them. Ok, to make things less complicated I'll drop machine.cpu-hotplug and leave it always enabled as it used to be and as Michael suggested. I'll drop following patches: 12, 13, 14, 20, 23 and respin series