Re: [PATCH v3 6/9] cpu/SMT: Allow enabling partial SMT states via sysfs

[Laurent Dufour]

Le 05/07/2023 à 05:14, Zhang, Rui a écrit :
> On Thu, 2023-06-29 at 16:31 +0200, Laurent Dufour wrote:
> > @@ -2580,6 +2597,17 @@ static ssize_t control_show(struct device
> > *dev,
> >   {
> >          const char *state = smt_states[cpu_smt_control];
> >   
> > +#ifdef CONFIG_HOTPLUG_SMT
> > +       /*
> > +        * If SMT is enabled but not all threads are enabled then
> > show the
> > +        * number of threads. If all threads are enabled show "on".
> > Otherwise
> > +        * show the state name.
> > +        */
> > +       if (cpu_smt_control == CPU_SMT_ENABLED &&
> > +           cpu_smt_num_threads != cpu_smt_max_threads)
> > +               return sysfs_emit(buf, "%d\n", cpu_smt_num_threads);
> > +#endif
> > +
>
> My understanding is that cpu_smt_control is always set to
> CPU_SMT_NOT_IMPLEMENTED when CONFIG_HOTPLUG_SMT is not set, so this
> ifdef is not necessary, right?

Hi Rui,

Indeed, cpu_smt_control, cpu_smt_num_threads and cpu_smt_max_threads are 
only defined when CONFIG_HOTPLUG_SMT is set. This is the reason for this 
#ifdef block.

This has been reported by the kernel test robot testing v2:
https://lore.kernel.org/oe-kbuild-all/202306282340.Ihqm0fLA-lkp@xxxxxxxxx

Cheers,
Laurent.