sched/debug: Add debugfs knob for "sched_debug"

I'm forever late for editing my kernel cmdline, add a runtime knob to
disable the "sched_debug" thing.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/sched/debug.c

···
 	.release	= single_release,
 };
 
+__read_mostly bool sched_debug_enabled;
+
 static __init int sched_init_debug(void)
 {
 	debugfs_create_file("sched_features", 0644, NULL, NULL,
 			&sched_feat_fops);
+
+	debugfs_create_bool("sched_debug", 0644, NULL,
+			&sched_debug_enabled);
 
 	return 0;
 }

kernel/sched/sched.h

···
 extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
 
 #ifdef	CONFIG_SCHED_DEBUG
+extern bool sched_debug_enabled;
+
 extern void print_cfs_stats(struct seq_file *m, int cpu);
 extern void print_rt_stats(struct seq_file *m, int cpu);
 extern void print_dl_stats(struct seq_file *m, int cpu);

kernel/sched/topology.c

···
 
 #ifdef CONFIG_SCHED_DEBUG
 
-static __read_mostly int sched_debug_enabled;
-
 static int __init sched_debug_setup(char *str)
 {
-	sched_debug_enabled = 1;
+	sched_debug_enabled = true;
 
 	return 0;
 }