Re: [PATCH V6 07/13] perf: Generic pci uncore device support

[Peter Zijlstra]

On Mon, 2012-06-18 at 11:06 +0800, Yan, Zheng wrote:
> On 06/16/2012 12:02 AM, Peter Zijlstra wrote:
> > On Fri, 2012-06-15 at 14:31 +0800, Yan, Zheng wrote:
> >> @@ -305,6 +310,22 @@ struct intel_uncore_box *uncore_alloc_box(int cpu)
> >>  static struct intel_uncore_box *
> >>  uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu)
> >>  {
> >> +       static struct intel_uncore_box *box;
> >> +
> >> +       box =  *per_cpu_ptr(pmu->box, cpu);
> >> +       if (box)
> >> +               return box;
> >> +
> >> +       raw_spin_lock(&uncore_box_lock);
> >> +       list_for_each_entry(box, &pmu->box_list, list) {
> >> +               if (box->phys_id == topology_physical_package_id(cpu)) {
> >> +                       atomic_inc(&box->refcnt);
> >> +                       *per_cpu_ptr(pmu->box, cpu) = box;
> >> +                       break;
> >> +               }
> >> +       }
> >> +       raw_spin_unlock(&uncore_box_lock);
> >> +
> >>         return *per_cpu_ptr(pmu->box, cpu);
> >>  } 
> > 
> > So why can't we do that lookup from a hotplug notifier?
> > 
> We can. But I personally prefer not to mix pci uncore initialization
> code with cpu hotplug notifier. Because pci hotplug and cpu hotplug
> are separate process, I'm not completely sure which one happens first.

I suspect nobody does.. OK we'll leave it as it is. Thanks
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/