Re: [PATCH] sched/fair: Use sched_energy_enabled()

[K Prateek Nayak]

Hello Vincent,

On 3/27/2026 6:50 PM, Vincent Guittot wrote:
> Use helper sched_energy_enabled() everywhere we want to test if EAS is
> enabled instead of mixing sched_energy_enabled() and direct call to
> static_branch_unlikely().
> 
> No functional change
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

Feel free to include:

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

> ---
>  kernel/sched/topology.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index 43150591914b..5847b83d9d55 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -273,7 +273,7 @@ void rebuild_sched_domains_energy(void)
>  static int sched_energy_aware_handler(const struct ctl_table *table, int write,
>  		void *buffer, size_t *lenp, loff_t *ppos)
>  {
> -	int ret, state;
> +	int ret;
>  
>  	if (write && !capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> @@ -289,8 +289,7 @@ static int sched_energy_aware_handler(const struct ctl_table *table, int write,
>  
>  	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
>  	if (!ret && write) {
> -		state = static_branch_unlikely(&sched_energy_present);
> -		if (state != sysctl_sched_energy_aware)
> +		if (sysctl_sched_energy_aware != sched_energy_enabled())

Quick tangential question:

Since "sysctl_sched_energy_aware" is initialized to "1", if
build_perf_domains() returns false at boot, sysctl_sched_energy_aware
and sched_energy_enabled() will go out of sync and reading
"/proc/sys/kernel/sched_energy_aware" will still show "1" despite EAS
being disabled.

Is that okay?

Some sysctls like numa_balancing will show 0 if disabled (by user or
due to lack of NUMA) reflecting the real state of system. Should
sched_energy_aware do the same?

>  			rebuild_sched_domains_energy();
>  	}
>  
-- 
Thanks and Regards,
Prateek