2005-09-01 15:48:51

by Protasevich, Natalie

Subject: RE: [Hotplug_sig] [patch 1/1] Hot plug CPU to support physical add of new processors (i386)

> > +#ifdef CONFIG_HOTPLUG_CPU
> > + if (cpu_online(cpu)) {
> > +#else
> > if (cpu_online(cpu) || !cpu_present(cpu)) {
> > +#endif
> > ret = -EINVAL;
> > goto out;
> > }
>
> Why this change? I think the cpu_present check is needed for
> ppc64 since it has non-present cpus in sysfs.
>

The new processor was never brought up, its bit is only set in
cpu_possible_map, but not in present map.

...
if (boot_error) {
/* Try to put things back the way they were before ...
*/
unmap_cpu_to_logical_apicid(cpu);
cpu_clear(cpu, cpu_callout_map); /* was set here
(do_boot_cpu()) */
cpu_clear(cpu, cpu_initialized); /* was set by
cpu_init() */
cpucount--;
} else {
x86_cpu_to_apicid[cpu] = apicid;
cpu_set(cpu, cpu_present_map); <=====================
}
...
So if someone tries to boot a CPU up first time during runtime it always
fails this check.
Thanks,
--Natalie

2005-09-01 15:59:48

by Nathan Lynch

Subject: Re: [Hotplug_sig] [patch 1/1] Hot plug CPU to support physical add of new processors (i386)

Protasevich, Natalie wrote:
> > > +#ifdef CONFIG_HOTPLUG_CPU
> > > + if (cpu_online(cpu)) {
> > > +#else
> > > if (cpu_online(cpu) || !cpu_present(cpu)) {
> > > +#endif
> > > ret = -EINVAL;
> > > goto out;
> > > }
> >
> > Why this change? I think the cpu_present check is needed for
> > ppc64 since it has non-present cpus in sysfs.
> >
>
> The new processor was never brought up, its bit is only set in
> cpu_possible_map, but not in present map.

If a cpu is physically present and is capable of being onlined it
should be marked in cpu_present_map, please. This change would break
ppc64; can you rework it?