sched: Move child_runs_first sysctls to fair.c

move child_runs_first sysctls to fair.c and use the new
register_sysctl_init() to register the sysctl interface.
Signed-off-by: Zhen Ni <nizhen@uniontech.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

include/linux/sched/sysctl.h

@@ -14,8 +14,6 @@ extern unsigned long sysctl_hung_task_timeout_secs;
 enum { sysctl_hung_task_timeout_secs = 0 };
 #endif
 
-extern unsigned int sysctl_sched_child_runs_first;
-
 enum sched_tunable_scaling {
 	SCHED_TUNABLESCALING_NONE,
 	SCHED_TUNABLESCALING_LOG,

kernel/sched/fair.c

@@ -109,6 +109,25 @@ static unsigned int sched_nr_latency = 8;
  * parent will (try to) run first.
  */
 unsigned int sysctl_sched_child_runs_first __read_mostly;
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_child_runs_first_sysctls[] = {
+	{
+		.procname       = "sched_child_runs_first",
+		.data           = &sysctl_sched_child_runs_first,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+	{}
+};
+
+static int __init sched_child_runs_first_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_child_runs_first_sysctls);
+	return 0;
+}
+late_initcall(sched_child_runs_first_sysctl_init);
+#endif
 
 /*
  * SCHED_OTHER wake-up granularity.

kernel/sched/sched.h

@@ -108,6 +108,8 @@ extern __read_mostly int scheduler_running;
 extern unsigned long calc_load_update;
 extern atomic_long_t calc_load_tasks;
 
+extern unsigned int sysctl_sched_child_runs_first;
+
 extern void calc_global_load_tick(struct rq *this_rq);
 extern long calc_load_fold_active(struct rq *this_rq, long adjust);
 

kernel/sysctl.c

@@ -1659,13 +1659,6 @@ int proc_do_static_key(struct ctl_table *table, int write,
 }
 
 static struct ctl_table kern_table[] = {
-	{
-		.procname	= "sched_child_runs_first",
-		.data		= &sysctl_sched_child_runs_first,
-		.maxlen		= sizeof(unsigned int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 #ifdef CONFIG_SCHEDSTATS
 	{
 		.procname	= "sched_schedstats",