Re: [PATCH] sched/uclamp: Fix unnused variable warning

[Peter Zijlstra]

On Tue, Oct 08, 2024 at 09:23:18AM +0100, Christian Loehle wrote:
> uclamp_mutex is only used for CONFIG_SYSCTL or
> CONFIG_UCLAMP_TASK_GROUP so ifdef that to fix the compile-time warning.
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202410060258.bPl2ZoUo-lkp@xxxxxxxxx/
> Signed-off-by: Christian Loehle <christian.loehle@xxxxxxx>
> ---
>  kernel/sched/core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 43e453ab7e20..18d9622eac8d 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1394,7 +1394,9 @@ void set_load_weight(struct task_struct *p, bool update_load)
>   * requests are serialized using a mutex to reduce the risk of conflicting
>   * updates or API abuses.
>   */
> +#if defined(CONFIG_UCLAMP_TASK_GROUP) || defined(CONFIG_SYSCTL)
>  static DEFINE_MUTEX(uclamp_mutex);
> +#endif
>  
>  /* Max allowed minimum utilization */
>  static unsigned int __maybe_unused sysctl_sched_uclamp_util_min = SCHED_CAPACITY_SCALE;
> -- 
> 2.34.1

Bah, too much email :/ But also,

  https://lkml.kernel.org/r/20241025073213.GE36494@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

where I said:

"sigh.. I hate our CONFIG space :/

Perhaps add __maybe_unused like the other variables it sits right next
to instead of adding yet more #ifdef crud?"