root/include/linux/tick.h

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DEFINITIONS

This source file includes following definitions.
  1. tick_cancel_sched_timer
  2. tick_clock_notify
  3. tick_check_oneshot_change
  4. tick_irq_enter
  5. tick_oneshot_mode_active
  6. tick_init
  7. tick_cancel_sched_timer
  8. tick_clock_notify
  9. tick_check_oneshot_change
  10. tick_irq_enter
  11. tick_oneshot_mode_active
  12. tick_nohz_tick_stopped
  13. tick_nohz_tick_stopped
  14. tick_nohz_idle_enter
  15. tick_nohz_idle_exit
  16. tick_nohz_get_sleep_length
  17. get_cpu_idle_time_us
  18. get_cpu_iowait_time_us
  19. tick_nohz_full_enabled
  20. tick_nohz_full_cpu
  21. tick_nohz_full_enabled
  22. tick_nohz_full_cpu
  23. __tick_nohz_full_check
  24. tick_nohz_full_kick_cpu
  25. tick_nohz_full_kick
  26. tick_nohz_full_kick_all
  27. __tick_nohz_task_switch
  28. is_housekeeping_cpu
  29. housekeeping_affine
  30. tick_nohz_full_check
  31. tick_nohz_task_switch
/*  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>
#include <linux/irqflags.h>
#include <linux/percpu.h>
#include <linux/hrtimer.h>
#include <linux/context_tracking_state.h>
#include <linux/cpumask.h>
#include <linux/sched.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
 * @last_tick:          Store the last tick expiry time when the tick
 *                      timer is modified for nohz sleeps. This is necessary
 *                      to resume the tick timer operation in the timeline
 *                      when the CPU returns from nohz sleep.
 * @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
 * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
 * @sleep_length:       Duration of the current idle sleep
 * @do_timer_lst:       CPU was the last one doing do_timer before going idle
 */
struct tick_sched {
        struct hrtimer                  sched_timer;
        unsigned long                   check_clocks;
        enum tick_nohz_mode             nohz_mode;
        ktime_t                         last_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                         iowait_sleeptime;
        ktime_t                         sleep_length;
        unsigned long                   last_jiffies;
        unsigned long                   next_jiffies;
        ktime_t                         idle_expires;
        int                             do_timer_last;
};

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_COMMON || 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 struct cpumask *tick_get_broadcast_mask(void);

#  ifdef CONFIG_TICK_ONESHOT
extern struct cpumask *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);
extern void tick_irq_enter(void);
extern int tick_oneshot_mode_active(void);
#  ifndef arch_needs_cpu
#   define arch_needs_cpu() (0)
#  endif
# else
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
static inline void tick_irq_enter(void) { }
static inline int tick_oneshot_mode_active(void) { 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; }
static inline void tick_irq_enter(void) { }
static inline int tick_oneshot_mode_active(void) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */

# ifdef CONFIG_NO_HZ_COMMON
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 /* !CONFIG_NO_HZ_COMMON */
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) { }

static inline ktime_t tick_nohz_get_sleep_length(void)
{
        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };

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

#ifdef CONFIG_NO_HZ_FULL
extern bool tick_nohz_full_running;
extern cpumask_var_t tick_nohz_full_mask;
extern cpumask_var_t housekeeping_mask;

static inline bool tick_nohz_full_enabled(void)
{
        if (!context_tracking_is_enabled())
                return false;

        return tick_nohz_full_running;
}

static inline bool tick_nohz_full_cpu(int cpu)
{
        if (!tick_nohz_full_enabled())
                return false;

        return cpumask_test_cpu(cpu, tick_nohz_full_mask);
}

extern void __tick_nohz_full_check(void);
extern void tick_nohz_full_kick(void);
extern void tick_nohz_full_kick_cpu(int cpu);
extern void tick_nohz_full_kick_all(void);
extern void __tick_nohz_task_switch(struct task_struct *tsk);
#else
static inline bool tick_nohz_full_enabled(void) { return false; }
static inline bool tick_nohz_full_cpu(int cpu) { return false; }
static inline void __tick_nohz_full_check(void) { }
static inline void tick_nohz_full_kick_cpu(int cpu) { }
static inline void tick_nohz_full_kick(void) { }
static inline void tick_nohz_full_kick_all(void) { }
static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
#endif

static inline bool is_housekeeping_cpu(int cpu)
{
#ifdef CONFIG_NO_HZ_FULL
        if (tick_nohz_full_enabled())
                return cpumask_test_cpu(cpu, housekeeping_mask);
#endif
        return true;
}

static inline void housekeeping_affine(struct task_struct *t)
{
#ifdef CONFIG_NO_HZ_FULL
        if (tick_nohz_full_enabled())
                set_cpus_allowed_ptr(t, housekeeping_mask);

#endif
}

static inline void tick_nohz_full_check(void)
{
        if (tick_nohz_full_enabled())
                __tick_nohz_full_check();
}

static inline void tick_nohz_task_switch(struct task_struct *tsk)
{
        if (tick_nohz_full_enabled())
                __tick_nohz_task_switch(tsk);
}


#endif
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