Re: [PATCH 14/36] cpuidle: Fix rcu_idle_*() usage

[Mark Rutland <mark.rutland@xxxxxxx>]

On Wed, Jun 08, 2022 at 04:27:37PM +0200, Peter Zijlstra wrote:
> --- a/kernel/time/tick-broadcast.c
> +++ b/kernel/time/tick-broadcast.c
> @@ -622,9 +622,13 @@ struct cpumask *tick_get_broadcast_onesh
>   * to avoid a deep idle transition as we are about to get the
>   * broadcast IPI right away.
>   */
> -int tick_check_broadcast_expired(void)
> +noinstr int tick_check_broadcast_expired(void)
>  {
> +#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
> +     return arch_test_bit(smp_processor_id(), 
> cpumask_bits(tick_broadcast_force_mask));
> +#else
>       return cpumask_test_cpu(smp_processor_id(), tick_broadcast_force_mask);
> +#endif
>  }

This is somewhat not-ideal. :/

Could we unconditionally do the arch_test_bit() variant, with a comment, or
does that not exist in some cases?

Thanks,
Mark.