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

[Dou Liyang <douly.fnst@cn.fujitsu.com>]

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@cn.fujitsu.com> 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);
>> +}
>