sched/debug: Remove the /proc/sys/kernel/sched_child_runs_first sysctl

The /proc/sys/kernel/sched_child_runs_first knob is no longer connected since:

   5e963f2 ("sched/fair: Commit to EEVDF")

Remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230920130025.412071-2-bigeasy@linutronix.de

kernel/sched/debug.c

@@ -864,7 +864,6 @@ static void sched_debug_header(struct seq_file *m)
 #define PN(x) \
 	SEQ_printf(m, "  .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
 	PN(sysctl_sched_base_slice);
-	P(sysctl_sched_child_runs_first);
 	P(sysctl_sched_features);
 #undef PN
 #undef P

kernel/sched/fair.c

@@ -78,12 +78,6 @@ unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
 unsigned int sysctl_sched_base_slice			= 750000ULL;
 static unsigned int normalized_sysctl_sched_base_slice	= 750000ULL;
 
-/*
- * After fork, child runs first. If set to 0 (default) then
- * parent will (try to) run first.
- */
-unsigned int sysctl_sched_child_runs_first __read_mostly;
-
 const_debug unsigned int sysctl_sched_migration_cost	= 500000UL;
 
 int sched_thermal_decay_shift;
@@ -145,13 +139,6 @@ static unsigned int sysctl_numa_balancing_promote_rate_limit = 65536;
 
 #ifdef CONFIG_SYSCTL
 static struct ctl_table sched_fair_sysctls[] = {
-	{
-		.procname       = "sched_child_runs_first",
-		.data           = &sysctl_sched_child_runs_first,
-		.maxlen         = sizeof(unsigned int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
-	},
 #ifdef CONFIG_CFS_BANDWIDTH
 	{
 		.procname       = "sched_cfs_bandwidth_slice_us",

kernel/sched/sched.h

@@ -100,8 +100,6 @@ 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);