Re: [PATCH] sched: do not call __put_task_struct() on rt if pi_blocked_on is set

[Steven Rostedt]

On Wed, 9 Apr 2025 13:27:12 -0300
"Luis Claudio R. Goncalves" <lgoncalv@xxxxxxxxxx> wrote:

> > > -	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
> > > +#ifdef CONFIG_PREEMPT_RT
> > > +	if (!preemptible() || current->pi_blocked_on)
> > > +		defer = true;
> > > +#endif  
> > 
> > Why add the ugly #ifdef back?
> > 
> > 	if (!IS_ENABLED(CONFIG_PREEMPT_RT) ||
> > 	    (preemptible() && !current->pi_blocked_on)) {  
> 
> I had to add the #ifdef to avoid the build failing if CONFIG_RT_MUTEXES is
> not set. I do know SMP, FUTEX, I2C, PSTORE and a few more things depend on
> CONFIG_RT_MUTEXES being enabled, but I opted for being thorough.
> 
> I would be more than glad getting rid of the #ifdef and simplifying the patch
> if that possible build failure is not a case to worry about, if RT_MUTEXES are
> always enabled nowadays.
> 

Because pi_blocked_on is only defined when CONFIG_RT_MUTEXES is enabled?

OK, then perhaps we should add in sched.h:

#ifdef CONFIG_RT_MUTEXES
static inline bool tsk_is_pi_blocked_on(struct task_struct *tsk)
{
	return tsk->pi_blocked_on != NULL;
}
#else
static inline bool tsk_is_pi_blocked_on(strut task_struct *tsk)
{
	return false;
}
#endif

??

-- Steve