Re: [PATCH 1/2] sched/deadline: use online cpus for validating runtime

[Juri Lelli <juri.lelli@redhat.com>]

Hi!

On 06/03/25 10:59, Shrikanth Hegde wrote:
> ftrace selftest reported failure since writing -1 to sched_rt_runtime_us
> return -EBUSY. This happens when the possible CPUs is different than
> the active CPUS.
> 
> Active CPUs are part of one root domain, while remaining CPUs are part
> of def_root_domain. Since active cpumask is being used, this results in
> cpus=0 when a non active CPUs is used in the loop.
> 
> Fix it by looping over the online CPUs instead for validation the
> bandwidth calculations.
> 
> Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
> ---
>  kernel/sched/deadline.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 2d0f571f95e9..7ea9c040c72f 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -3187,7 +3187,7 @@ int sched_dl_global_validate(void)
>  	 * value smaller than the currently allocated bandwidth in
>  	 * any of the root_domains.
>  	 */
> -	for_each_possible_cpu(cpu) {
> +	for_each_online_cpu(cpu) {
>  		rcu_read_lock_sched();
>  
>  		if (dl_bw_visited(cpu, gen))
> -- 

Makes sense to me.

Acked-by: Juri Lelli <juri.lelli@redhat.com>

Thanks,
Juri