Re: [RFC PATCH] ACPI / processor: Get accurate possible CPU count

[Dou Liyang]

Hi Andy,

At 03/15/2018 01:24 AM, Andy Shevchenko wrote:
> On Wed, Mar 14, 2018 at 12:28 PM, Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> wrote:
>
> > +static void __init acpi_update_possible_map(void)
> > +{
> > +       unsigned int cpu, nr = 0;
> > +
>
> > +       if (nr_cpu_ids <= nr_unique_ids)
> > +               return;
> > +
> > +       for_each_possible_cpu(cpu) {
> > +               if (nr >= nr_unique_ids)
> > +                       set_cpu_possible(cpu, false);
> > +               nr++;
> > +       }
>
> IIUC this can be optimized to:

Yes, I agree, It's smarter and clearer. Will use it.

Thanks,
	dou

> if (nr_unique_ids >= nr_cpu_ids)
>      return;
>
> /* Don't yet figure out if it's superfluous */
> if (nr_unique_ids >= cpumask_last(cpu_possible_mask))
>      return;
>
> for_each_cpu_wrap(cpu, cpu_possible_mask, nr_unique_ids)
>      set_cpu_possible(cpu, false);



> > +       nr_cpu_ids = nr_unique_ids;
> > +       pr_info("Allowing %d possible CPUs\n", nr_cpu_ids);
> > +}