LXR linux/include/linux/tick.h

   1/*  linux/include/linux/tick.h
   2 *
   3 *  This file contains the structure definitions for tick related functions
   4 *
   5 */
   6#ifndef _LINUX_TICK_H
   7#define _LINUX_TICK_H
   8
   9#include <linux/clockchips.h>
  10
  11#ifdef CONFIG_GENERIC_CLOCKEVENTS
  12
  13enum tick_device_mode {
  14        TICKDEV_MODE_PERIODIC,
  15        TICKDEV_MODE_ONESHOT,
  16};
  17
  18struct tick_device {
  19        struct clock_event_device *evtdev;
  20        enum tick_device_mode mode;
  21};
  22
  23enum tick_nohz_mode {
  24        NOHZ_MODE_INACTIVE,
  25        NOHZ_MODE_LOWRES,
  26        NOHZ_MODE_HIGHRES,
  27};
  28
  29/**
  30 * struct tick_sched - sched tick emulation and no idle tick control/stats
  31 * @sched_timer:        hrtimer to schedule the periodic tick in high
  32 *                      resolution mode
  33 * @idle_tick:          Store the last idle tick expiry time when the tick
  34 *                      timer is modified for idle sleeps. This is necessary
  35 *                      to resume the tick timer operation in the timeline
  36 *                      when the CPU returns from idle
  37 * @tick_stopped:       Indicator that the idle tick has been stopped
  38 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  39 * @idle_calls:         Total number of idle calls
  40 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  41 * @idle_entrytime:     Time when the idle call was entered
  42 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  43 * @sleep_length:       Duration of the current idle sleep
  44 */
  45struct tick_sched {
  46        struct hrtimer                  sched_timer;
  47        unsigned long                   check_clocks;
  48        enum tick_nohz_mode             nohz_mode;
  49        ktime_t                         idle_tick;
  50        int                             tick_stopped;
  51        unsigned long                   idle_jiffies;
  52        unsigned long                   idle_calls;
  53        unsigned long                   idle_sleeps;
  54        ktime_t                         idle_entrytime;
  55        ktime_t                         idle_sleeptime;
  56        ktime_t                         sleep_length;
  57        unsigned long                   last_jiffies;
  58        unsigned long                   next_jiffies;
  59        ktime_t                         idle_expires;
  60};
  61
  62extern void __init tick_init(void);
  63extern int tick_is_oneshot_available(void);
  64extern struct tick_device *tick_get_device(int cpu);
  65
  66# ifdef CONFIG_HIGH_RES_TIMERS
  67extern int tick_init_highres(void);
  68extern int tick_program_event(ktime_t expires, int force);
  69extern void tick_setup_sched_timer(void);
  70extern void tick_cancel_sched_timer(int cpu);
  71# else
  72static inline void tick_cancel_sched_timer(int cpu) { }
  73# endif /* HIGHRES */
  74
  75# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  76extern struct tick_device *tick_get_broadcast_device(void);
  77extern cpumask_t *tick_get_broadcast_mask(void);
  78
  79#  ifdef CONFIG_TICK_ONESHOT
  80extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
  81#  endif
  82
  83# endif /* BROADCAST */
  84
  85# ifdef CONFIG_TICK_ONESHOT
  86extern void tick_clock_notify(void);
  87extern int tick_check_oneshot_change(int allow_nohz);
  88extern struct tick_sched *tick_get_tick_sched(int cpu);
  89# else
  90static inline void tick_clock_notify(void) { }
  91static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
  92# endif
  93
  94#else /* CONFIG_GENERIC_CLOCKEVENTS */
  95static inline void tick_init(void) { }
  96static inline void tick_cancel_sched_timer(int cpu) { }
  97static inline void tick_clock_notify(void) { }
  98static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
  99#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 100
 101# ifdef CONFIG_NO_HZ
 102extern void tick_nohz_stop_sched_tick(void);
 103extern void tick_nohz_restart_sched_tick(void);
 104extern void tick_nohz_update_jiffies(void);
 105extern ktime_t tick_nohz_get_sleep_length(void);
 106# else
 107static inline void tick_nohz_stop_sched_tick(void) { }
 108static inline void tick_nohz_restart_sched_tick(void) { }
 109static inline void tick_nohz_update_jiffies(void) { }
 110static inline ktime_t tick_nohz_get_sleep_length(void)
 111{
 112        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 113
 114        return len;
 115}
 116# endif /* !NO_HZ */
 117
 118#endif
 119