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

[Steven Rostedt]

On Tue, 8 Apr 2025 21:27:37 -0300
"Luis Claudio R. Goncalves" <lgoncalv@xxxxxxxxxx> wrote:

>  {
> +	bool defer = false;
> +
>  	if (!refcount_dec_and_test(&t->usage))
>  		return;
>  
>  	/*
>  	 * In !RT, it is always safe to call __put_task_struct().
> -	 * Under RT, we can only call it in preemptible context.
> +	 * Under RT, we can only call it in preemptible context,
> +	 * when not blocked on a PI chain.
>  	 */
> -	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)) {

-- Steve

> +
> +	if (!defer) {
>  		static DEFINE_WAIT_OVERRIDE_MAP(put_task_map, LD_WAIT_SLEEP);
>  
>