Re: [PATCH] sched: fair: drop useless cpumask_empty() in find_energy_efficient_cpu()

[Madadi Vineeth Reddy <vineethr@linux.ibm.com>]

On 11/09/25 08:04, Yury Norov wrote:
> From: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> 
> cpumask_empty() call is O(N) and useless, because the previous
> cpumask_and() returns false for empty 'cpus'.
> 

LGTM

Reviewed-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>

Thanks,
Madadi Vineeth Reddy

> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>  kernel/sched/fair.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index b173a059315c..7229339cbb1b 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8320,9 +8320,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
>  		int max_spare_cap_cpu = -1;
>  		int fits, max_fits = -1;
>  
> -		cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask);
> -
> -		if (cpumask_empty(cpus))
> +		if (!cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask))
>  			continue;
>  
>  		/* Account external pressure for the energy estimation */