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_waketime:      Time when the idle was interrupted
  43  * @idle_exittime:      Time when the idle state was left
  44  * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  45  * @sleep_length:       Duration of the current idle sleep
  46  */
  47 struct tick_sched {
  48         struct hrtimer                  sched_timer;
  49         unsigned long                   check_clocks;
  50         enum tick_nohz_mode             nohz_mode;
  51         ktime_t                         idle_tick;
  52         int                             tick_stopped;
  53         unsigned long                   idle_jiffies;
  54         unsigned long                   idle_calls;
  55         unsigned long                   idle_sleeps;
  56         int                             idle_active;
  57         ktime_t                         idle_entrytime;
  58         ktime_t                         idle_waketime;
  59         ktime_t                         idle_exittime;
  60         ktime_t                         idle_sleeptime;
  61         ktime_t                         idle_lastupdate;
  62         ktime_t                         sleep_length;
  63         unsigned long                   last_jiffies;
  64         unsigned long                   next_jiffies;
  65         ktime_t                         idle_expires;
  66 };
  67
  68 extern void __init tick_init(void);
  69 extern int tick_is_oneshot_available(void);
  70 extern struct tick_device *tick_get_device(int cpu);
  71
  72 # ifdef CONFIG_HIGH_RES_TIMERS
  73 extern int tick_init_highres(void);
  74 extern int tick_program_event(ktime_t expires, int force);
  75 extern void tick_setup_sched_timer(void);
  76 extern void tick_cancel_sched_timer(int cpu);
  77 # else
  78 static inline void tick_cancel_sched_timer(int cpu) { }
  79 # endif /* HIGHRES */
  80
  81 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  82 extern struct tick_device *tick_get_broadcast_device(void);
  83 extern cpumask_t *tick_get_broadcast_mask(void);
  84
  85 #  ifdef CONFIG_TICK_ONESHOT
  86 extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
  87 #  endif
  88
  89 # endif /* BROADCAST */
  90
  91 # ifdef CONFIG_TICK_ONESHOT
  92 extern void tick_clock_notify(void);
  93 extern int tick_check_oneshot_change(int allow_nohz);
  94 extern struct tick_sched *tick_get_tick_sched(int cpu);
  95 # else
  96 static inline void tick_clock_notify(void) { }
  97 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
  98 # endif
  99
 100 #else /* CONFIG_GENERIC_CLOCKEVENTS */
 101 static inline void tick_init(void) { }
 102 static inline void tick_cancel_sched_timer(int cpu) { }
 103 static inline void tick_clock_notify(void) { }
 104 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 105 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 106
 107 # ifdef CONFIG_NO_HZ
 108 extern void tick_nohz_stop_sched_tick(void);
 109 extern void tick_nohz_restart_sched_tick(void);
 110 extern void tick_nohz_update_jiffies(void);
 111 extern ktime_t tick_nohz_get_sleep_length(void);
 112 extern void tick_nohz_stop_idle(int cpu);
 113 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 114 # else
 115 static inline void tick_nohz_stop_sched_tick(void) { }
 116 static inline void tick_nohz_restart_sched_tick(void) { }
 117 static inline void tick_nohz_update_jiffies(void) { }
 118 static inline ktime_t tick_nohz_get_sleep_length(void)
 119 {
 120         ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 121
 122         return len;
 123 }
 124 static inline void tick_nohz_stop_idle(int cpu) { }
 125 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return 0; }
 126 # endif /* !NO_HZ */
 127
 128 #endif