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
  13 enum tick_device_mode {
  14         TICKDEV_MODE_PERIODIC,
  15         TICKDEV_MODE_ONESHOT,
  16 };
  17
  18 struct tick_device {
  19         struct clock_event_device *evtdev;
  20         enum tick_device_mode mode;
  21 };
  22
  23 enum 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  */
  45 struct 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
  62 extern void __init tick_init(void);
  63 extern int tick_is_oneshot_available(void);
  64 extern struct tick_device *tick_get_device(int cpu);
  65
  66 # ifdef CONFIG_HIGH_RES_TIMERS
  67 extern int tick_init_highres(void);
  68 extern int tick_program_event(ktime_t expires, int force);
  69 extern void tick_setup_sched_timer(void);
  70 extern void tick_cancel_sched_timer(int cpu);
  71 # else
  72 static inline void tick_cancel_sched_timer(int cpu) { }
  73 # endif /* HIGHRES */
  74
  75 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  76 extern struct tick_device *tick_get_broadcast_device(void);
  77 extern cpumask_t *tick_get_broadcast_mask(void);
  78
  79 #  ifdef CONFIG_TICK_ONESHOT
  80 extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
  81 #  endif
  82
  83 # endif /* BROADCAST */
  84
  85 # ifdef CONFIG_TICK_ONESHOT
  86 extern void tick_clock_notify(void);
  87 extern int tick_check_oneshot_change(int allow_nohz);
  88 extern struct tick_sched *tick_get_tick_sched(int cpu);
  89 # else
  90 static inline void tick_clock_notify(void) { }
  91 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
  92 # endif
  93
  94 #else /* CONFIG_GENERIC_CLOCKEVENTS */
  95 static inline void tick_init(void) { }
  96 static inline void tick_cancel_sched_timer(int cpu) { }
  97 static inline void tick_clock_notify(void) { }
  98 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
  99 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 100
 101 # ifdef CONFIG_NO_HZ
 102 extern void tick_nohz_stop_sched_tick(void);
 103 extern void tick_nohz_restart_sched_tick(void);
 104 extern void tick_nohz_update_jiffies(void);
 105 extern ktime_t tick_nohz_get_sleep_length(void);
 106 # else
 107 static inline void tick_nohz_stop_sched_tick(void) { }
 108 static inline void tick_nohz_restart_sched_tick(void) { }
 109 static inline void tick_nohz_update_jiffies(void) { }
 110 static 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