root/include/linux/tick.h

INCLUDED FROM

DEFINITIONS

1. tick_cancel_sched_timer
2. tick_clock_notify
3. tick_check_oneshot_change
4. tick_init
5. tick_cancel_sched_timer
6. tick_clock_notify
7. tick_check_oneshot_change
8. tick_nohz_stop_sched_tick
9. tick_nohz_restart_sched_tick
10. tick_nohz_update_jiffies
11. tick_nohz_get_sleep_length
12. tick_nohz_stop_idle
13. get_cpu_idle_time_us

/*  linux/include/linux/tick.h
 *
 *  This file contains the structure definitions for tick related functions
 *
 */
#ifndef _LINUX_TICK_H
#define _LINUX_TICK_H

#include <linux/clockchips.h>

#ifdef CONFIG_GENERIC_CLOCKEVENTS

enum tick_device_mode {
        TICKDEV_MODE_PERIODIC,
        TICKDEV_MODE_ONESHOT,
};

struct tick_device {
        struct clock_event_device *evtdev;
        enum tick_device_mode mode;
};

enum tick_nohz_mode {
        NOHZ_MODE_INACTIVE,
        NOHZ_MODE_LOWRES,
        NOHZ_MODE_HIGHRES,
};

/**
 * struct tick_sched - sched tick emulation and no idle tick control/stats
 * @sched_timer:        hrtimer to schedule the periodic tick in high
 *                      resolution mode
 * @idle_tick:          Store the last idle tick expiry time when the tick
 *                      timer is modified for idle sleeps. This is necessary
 *                      to resume the tick timer operation in the timeline
 *                      when the CPU returns from idle
 * @tick_stopped:       Indicator that the idle tick has been stopped
 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
 * @idle_calls:         Total number of idle calls
 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
 * @idle_entrytime:     Time when the idle call was entered
 * @idle_waketime:      Time when the idle was interrupted
 * @idle_exittime:      Time when the idle state was left
 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
 * @sleep_length:       Duration of the current idle sleep
 */
struct tick_sched {
        struct hrtimer                  sched_timer;
        unsigned long                   check_clocks;
        enum tick_nohz_mode             nohz_mode;
        ktime_t                         idle_tick;
        int                             inidle;
        int                             tick_stopped;
        unsigned long                   idle_jiffies;
        unsigned long                   idle_calls;
        unsigned long                   idle_sleeps;
        int                             idle_active;
        ktime_t                         idle_entrytime;
        ktime_t                         idle_waketime;
        ktime_t                         idle_exittime;
        ktime_t                         idle_sleeptime;
        ktime_t                         idle_lastupdate;
        ktime_t                         sleep_length;
        unsigned long                   last_jiffies;
        unsigned long                   next_jiffies;
        ktime_t                         idle_expires;
};

extern void __init tick_init(void);
extern int tick_is_oneshot_available(void);
extern struct tick_device *tick_get_device(int cpu);

# ifdef CONFIG_HIGH_RES_TIMERS
extern int tick_init_highres(void);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_setup_sched_timer(void);
# endif

# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
extern void tick_cancel_sched_timer(int cpu);
# else
static inline void tick_cancel_sched_timer(int cpu) { }
# endif

# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern struct tick_device *tick_get_broadcast_device(void);
extern cpumask_t *tick_get_broadcast_mask(void);

#  ifdef CONFIG_TICK_ONESHOT
extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
#  endif

# endif /* BROADCAST */

# ifdef CONFIG_TICK_ONESHOT
extern void tick_clock_notify(void);
extern int tick_check_oneshot_change(int allow_nohz);
extern struct tick_sched *tick_get_tick_sched(int cpu);
# else
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
# endif

#else /* CONFIG_GENERIC_CLOCKEVENTS */
static inline void tick_init(void) { }
static inline void tick_cancel_sched_timer(int cpu) { }
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */

# ifdef CONFIG_NO_HZ
extern void tick_nohz_stop_sched_tick(int inidle);
extern void tick_nohz_restart_sched_tick(void);
extern void tick_nohz_update_jiffies(void);
extern ktime_t tick_nohz_get_sleep_length(void);
extern void tick_nohz_stop_idle(int cpu);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
# else
static inline void tick_nohz_stop_sched_tick(int inidle) { }
static inline void tick_nohz_restart_sched_tick(void) { }
static inline void tick_nohz_update_jiffies(void) { }
static inline ktime_t tick_nohz_get_sleep_length(void)
{
        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };

        return len;
}
static inline void tick_nohz_stop_idle(int cpu) { }
static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
# endif /* !NO_HZ */

#endif