Commit 33a5f626 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

nohz: Add API to check tick state 



We need some quick way to check if the CPU has stopped
its tick. This will be useful to implement the printk tick
using the irq work subsystem.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
parent 6147a9d8

include/linux/tick.h

+16 −1
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 


#include <linux/clockchips.h>

#include <linux/irqflags.h>

#include <linux/percpu.h>

#include <linux/hrtimer.h>



#ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -122,13 +124,26 @@ static inline int tick_oneshot_mode_active(void) { return 0; } 
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */



# ifdef CONFIG_NO_HZ

DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);



static inline int tick_nohz_tick_stopped(void)

{

	return __this_cpu_read(tick_cpu_sched.tick_stopped);

}



extern void tick_nohz_idle_enter(void);

extern void tick_nohz_idle_exit(void);

extern void tick_nohz_irq_exit(void);

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



# else /* !CONFIG_NO_HZ */

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

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ 
/*

 * Per cpu nohz control structure

 */

static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);

DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);



/*

 * The time, when the last jiffy update happened. Protected by xtime_lock.