Re: [PATCH 2/5] sched/topology: Wrappers for sched_domains_mutex

[Waiman Long]

On 3/4/25 10:05 AM, Waiman Long wrote:
> > --- a/kernel/sched/topology.c
> > +++ b/kernel/sched/topology.c
> > @@ -6,6 +6,19 @@
> >   #include <linux/bsearch.h>
> >     DEFINE_MUTEX(sched_domains_mutex);
> > +#ifdef CONFIG_SMP
> > +void sched_domains_mutex_lock(void)
> > +{
> > +    mutex_lock(&sched_domains_mutex);
> > +}
> > +void sched_domains_mutex_unlock(void)
> > +{
> > +    mutex_unlock(&sched_domains_mutex);
> > +}
> > +#else
> > +void sched_domains_mutex_lock(void) { }
> > +void sched_domains_mutex_unlock(void) { }
> > +#endif
> >     /* Protected by sched_domains_mutex: */
> >   static cpumask_var_t sched_domains_tmpmask;
> > @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int 
> > ndoms_new, cpumask_var_t doms_new[],
> >   void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> >                    struct sched_domain_attr *dattr_new)
> >   {
> > -    mutex_lock(&sched_domains_mutex);
> > +    sched_domains_mutex_lock();
> >       partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> > -    mutex_unlock(&sched_domains_mutex);
> > +    sched_domains_mutex_unlock();
> >   }
>
> There are two "lockdep_assert_held(&sched_domains_mutex);" statements 
> in topology.c file and one in cpuset.c. That can be problematic in the 
> non-SMP case. Maybe another wrapper to do the assert?

Ignore that as both topology.c and cpuset.c will only be compiled if 
CONFIG_SMP is defined. IOW, you don't need the the "#ifdef CONFIG_SMP" 
above.

Cheers,
Longman