time: nohz: Expose tick_nohz_enabled

The cpuidle subsystem needs it.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/tick.h

@@ -98,6 +98,7 @@ static inline void tick_broadcast_exit(void)
 }
 
 #ifdef CONFIG_NO_HZ_COMMON
+extern int tick_nohz_enabled;
 extern int tick_nohz_tick_stopped(void);
 extern void tick_nohz_idle_enter(void);
 extern void tick_nohz_idle_exit(void);
@@ -106,6 +107,7 @@ extern ktime_t tick_nohz_get_sleep_length(void);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 #else /* !CONFIG_NO_HZ_COMMON */
+#define tick_nohz_enabled (0)
 static inline int tick_nohz_tick_stopped(void) { return 0; }
 static inline void tick_nohz_idle_enter(void) { }
 static inline void tick_nohz_idle_exit(void) { }

kernel/time/tick-sched.c

@@ -387,7 +387,7 @@ void __init tick_nohz_init(void)
 /*
  * NO HZ enabled ?
  */
-static int tick_nohz_enabled __read_mostly  = 1;
+int tick_nohz_enabled __read_mostly = 1;
 unsigned long tick_nohz_active  __read_mostly;
 /*
  * Enable / Disable tickless mode