Re: [PATCH -next] sched/rt: fix build error when CONFIG_SYSCTL is disable

[Ingo Molnar <mingo@kernel.org>]

I believe these build errors are caused by new commits in the sysctl-next 
tree that change scheduler code:

  4925401d06dc sched: Move rr_timeslice sysctls to rt.c
  5f6e55c2485c sched: Move rt_period/runtime sysctls to rt.c

In particular I don't see any Cc: to scheduler folks in these two commits - 
and I'd have preferred to pick these up into the scheduler tree, to avoid 
the merge conflicts and the build failure regressions...

Thanks,

	Ingo


* Baisong Zhong <zhongbaisong@huawei.com> wrote:

> Avoid random build errors which do not select
> CONFIG_SYSCTL by depending on it in Kconfig.
> 
> This fixes the following warning:
> 
> In file included from kernel/sched/build_policy.c:43:
> At top level:
> kernel/sched/rt.c:3017:12: error: ‘sched_rr_handler’ defined but not used [-Werror=unused-function]
>  3017 | static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
>       |            ^~~~~~~~~~~~~~~~
> kernel/sched/rt.c:2978:12: error: ‘sched_rt_handler’ defined but not used [-Werror=unused-function]
>  2978 | static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
>       |            ^~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> make[2]: *** [scripts/Makefile.build:310: kernel/sched/build_policy.o] Error 1
> make[1]: *** [scripts/Makefile.build:638: kernel/sched] Error 2
> make[1]: *** Waiting for unfinished jobs....
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Baisong Zhong <zhongbaisong@huawei.com>
> ---
>  kernel/sched/rt.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 71791be36065..ee319581b1cd 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -5,7 +5,6 @@
>   */
>  
>  int sched_rr_timeslice = RR_TIMESLICE;
> -static int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE;
>  /* More than 4 hours if BW_SHIFT equals 20. */
>  static const u64 max_rt_runtime = MAX_BW;
>  
> @@ -25,11 +24,12 @@ unsigned int sysctl_sched_rt_period = 1000000;
>   */
>  int sysctl_sched_rt_runtime = 950000;
>  
> +#ifdef CONFIG_SYSCTL
> +static int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE;
>  static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
>  		size_t *lenp, loff_t *ppos);
>  static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
>  		size_t *lenp, loff_t *ppos);
> -#ifdef CONFIG_SYSCTL
>  static struct ctl_table sched_rt_sysctls[] = {
>  	{
>  		.procname       = "sched_rt_period_us",
> @@ -2911,6 +2911,7 @@ long sched_group_rt_period(struct task_group *tg)
>  	return rt_period_us;
>  }
>  
> +#ifdef CONFIG_SYSCTL
>  static int sched_rt_global_constraints(void)
>  {
>  	int ret = 0;
> @@ -2930,8 +2931,11 @@ int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
>  
>  	return 1;
>  }
> +#endif /* CONFIG_SYSCTL */
>  
>  #else /* !CONFIG_RT_GROUP_SCHED */
> +
> +#ifdef CONFIG_SYSCTL
>  static int sched_rt_global_constraints(void)
>  {
>  	unsigned long flags;
> @@ -2949,8 +2953,10 @@ static int sched_rt_global_constraints(void)
>  
>  	return 0;
>  }
> +#endif /* CONFIG_SYSCTL */
>  #endif /* CONFIG_RT_GROUP_SCHED */
>  
> +#ifdef CONFIG_SYSCTL
>  static int sched_rt_global_validate(void)
>  {
>  	if (sysctl_sched_rt_period <= 0)
> @@ -3035,6 +3041,7 @@ static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
>  
>  	return ret;
>  }
> +#endif /* CONFIG_SYSCTL */
>  
>  #ifdef CONFIG_SCHED_DEBUG
>  void print_rt_stats(struct seq_file *m, int cpu)
> -- 
> 2.25.1
>