Re: [PATCH] sched/psi: use for_each_set_bit() in psi_group_change() task-count walk

[K Prateek Nayak]

Hello Usama,

On 7/14/2026 7:50 PM, Usama Arif wrote:
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index d9c9d9480a45..f5ae1ceb21a7 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -798,7 +798,8 @@ static void psi_group_change(struct psi_group *group, int cpu,
>  			     u64 now, bool wake_clock)
>  {
>  	struct psi_group_cpu *groupc;
> -	unsigned int t, m;
> +	unsigned long clear_bits, set_bits;
> +	unsigned int t;
>  	u32 state_mask;
>  
>  	lockdep_assert_rq_held(cpu_rq(cpu));
> @@ -824,9 +825,8 @@ static void psi_group_change(struct psi_group *group, int cpu,
>  	 * The rest of the state mask is calculated based on the task
>  	 * counts. Update those first, then construct the mask.
>  	 */
> -	for (t = 0, m = clear; m; m &= ~(1 << t), t++) {
> -		if (!(m & (1 << t)))
> -			continue;
> +	clear_bits = clear;

nit.

Can't we convert the arguments to unsigned long instead of assigning
them to these local variables?

Apart form that, for_each_set_bit() is indeed much cleaner. Feel free
to include:

Reviewed-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>

> +	for_each_set_bit(t, &clear_bits, NR_PSI_TASK_COUNTS) {
>  		if (groupc->tasks[t]) {
>  			groupc->tasks[t]--;
>  		} else if (!psi_bug) {

-- 
Thanks and Regards,
Prateek