Re: [Qemu-devel] [PATCH 8/8] [PATCH RFC v2] s390-qemu: cpu hotplug - Treat S390 cpus as devices

[Jason J. Herne]

On 07/30/2013 03:24 AM, Igor Mammedov wrote:
> On Mon, 29 Jul 2013 15:41:57 -0400
> "Jason J. Herne" <address@hidden> wrote:
>
> > On 06/08/2013 09:11 PM, Andreas Färber wrote:
> > > >    if (tcg_enabled() && !inited) {
> > > > >           inited = true;
> > > > >           s390x_translate_init();
> > > > >       }
> > > > > +
> > > > > +    smp_cpus += 1;
> > > Won't we need some form of locking?
> > >
> > > If we fiddle with a global CPU counter, we should do so in qom/cpu.c,
> > > not just in s390x code.
> >
> > I've redesigned a lot of this to make it simpler and less intrusive.
> > I'm almost ready to post the next revision but I'm hung up on this one
> > thing.
> >
> > I moved the smp_cpu increment to qom/cpu.c : cpu_common_realizefn.
> > However this seems to break the user mode target because smp_cpus does
> > not exist.  I tried wrapping the increment in a #ifndef CONFIG_USER_ONLY
> > statement but it seems to have no effect.  I think the reason for that
> > is because CONFIG_USER_ONLY is added to config-target.h which is not
> > actually generated until after we compile qom/cpu.c.
> >
> > ...
> >     CC    qom/object.o
> >     CC    qom/container.o
> >     CC    qom/qom-qobject.o
> >     CC    qom/cpu.o
> >     CC    hw/core/qdev.o
> >     CC    hw/core/qdev-properties.o
> >     CC    hw/core/irq.o
> >     GEN   s390x-linux-user/config-target.h
> >     CC    s390x-linux-user/exec.o
> > ...
> >
> > Is there another place I should put the increment?
>
> Could you just use current number of cpus instead of smp_cpus increment?

Is there an easier way of getting the count besides this?

int cpu_count = 0;
for (cpu = first_cpu; cpu != NULL; cpu = cpu->next_cpu) {
    cpu_count++;
}




--
-- Jason J. Herne (address@hidden)