linux/include/linux/tick.h
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   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#include <linux/irqflags.h>
  11#include <linux/percpu.h>
  12#include <linux/hrtimer.h>
  13
  14#ifdef CONFIG_GENERIC_CLOCKEVENTS
  15
  16enum tick_device_mode {
  17        TICKDEV_MODE_PERIODIC,
  18        TICKDEV_MODE_ONESHOT,
  19};
  20
  21struct tick_device {
  22        struct clock_event_device *evtdev;
  23        enum tick_device_mode mode;
  24};
  25
  26enum tick_nohz_mode {
  27        NOHZ_MODE_INACTIVE,
  28        NOHZ_MODE_LOWRES,
  29        NOHZ_MODE_HIGHRES,
  30};
  31
  32/**
  33 * struct tick_sched - sched tick emulation and no idle tick control/stats
  34 * @sched_timer:        hrtimer to schedule the periodic tick in high
  35 *                      resolution mode
  36 * @last_tick:          Store the last tick expiry time when the tick
  37 *                      timer is modified for nohz sleeps. This is necessary
  38 *                      to resume the tick timer operation in the timeline
  39 *                      when the CPU returns from nohz sleep.
  40 * @tick_stopped:       Indicator that the idle tick has been stopped
  41 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  42 * @idle_calls:         Total number of idle calls
  43 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  44 * @idle_entrytime:     Time when the idle call was entered
  45 * @idle_waketime:      Time when the idle was interrupted
  46 * @idle_exittime:      Time when the idle state was left
  47 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  48 * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
  49 * @sleep_length:       Duration of the current idle sleep
  50 * @do_timer_lst:       CPU was the last one doing do_timer before going idle
  51 */
  52struct tick_sched {
  53        struct hrtimer                  sched_timer;
  54        unsigned long                   check_clocks;
  55        enum tick_nohz_mode             nohz_mode;
  56        ktime_t                         last_tick;
  57        int                             inidle;
  58        int                             tick_stopped;
  59        unsigned long                   idle_jiffies;
  60        unsigned long                   idle_calls;
  61        unsigned long                   idle_sleeps;
  62        int                             idle_active;
  63        ktime_t                         idle_entrytime;
  64        ktime_t                         idle_waketime;
  65        ktime_t                         idle_exittime;
  66        ktime_t                         idle_sleeptime;
  67        ktime_t                         iowait_sleeptime;
  68        ktime_t                         sleep_length;
  69        unsigned long                   last_jiffies;
  70        unsigned long                   next_jiffies;
  71        ktime_t                         idle_expires;
  72        int                             do_timer_last;
  73};
  74
  75extern void __init tick_init(void);
  76extern int tick_is_oneshot_available(void);
  77extern struct tick_device *tick_get_device(int cpu);
  78
  79# ifdef CONFIG_HIGH_RES_TIMERS
  80extern int tick_init_highres(void);
  81extern int tick_program_event(ktime_t expires, int force);
  82extern void tick_setup_sched_timer(void);
  83# endif
  84
  85# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
  86extern void tick_cancel_sched_timer(int cpu);
  87# else
  88static inline void tick_cancel_sched_timer(int cpu) { }
  89# endif
  90
  91# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  92extern struct tick_device *tick_get_broadcast_device(void);
  93extern struct cpumask *tick_get_broadcast_mask(void);
  94
  95#  ifdef CONFIG_TICK_ONESHOT
  96extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
  97#  endif
  98
  99# endif /* BROADCAST */
 100
 101# ifdef CONFIG_TICK_ONESHOT
 102extern void tick_clock_notify(void);
 103extern int tick_check_oneshot_change(int allow_nohz);
 104extern struct tick_sched *tick_get_tick_sched(int cpu);
 105extern void tick_check_idle(int cpu);
 106extern int tick_oneshot_mode_active(void);
 107#  ifndef arch_needs_cpu
 108#   define arch_needs_cpu(cpu) (0)
 109#  endif
 110# else
 111static inline void tick_clock_notify(void) { }
 112static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 113static inline void tick_check_idle(int cpu) { }
 114static inline int tick_oneshot_mode_active(void) { return 0; }
 115# endif
 116
 117#else /* CONFIG_GENERIC_CLOCKEVENTS */
 118static inline void tick_init(void) { }
 119static inline void tick_cancel_sched_timer(int cpu) { }
 120static inline void tick_clock_notify(void) { }
 121static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 122static inline void tick_check_idle(int cpu) { }
 123static inline int tick_oneshot_mode_active(void) { return 0; }
 124#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 125
 126# ifdef CONFIG_NO_HZ
 127DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
 128
 129static inline int tick_nohz_tick_stopped(void)
 130{
 131        return __this_cpu_read(tick_cpu_sched.tick_stopped);
 132}
 133
 134extern void tick_nohz_idle_enter(void);
 135extern void tick_nohz_idle_exit(void);
 136extern void tick_nohz_irq_exit(void);
 137extern ktime_t tick_nohz_get_sleep_length(void);
 138extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 139extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 140
 141# else /* !CONFIG_NO_HZ */
 142static inline int tick_nohz_tick_stopped(void)
 143{
 144        return 0;
 145}
 146
 147static inline void tick_nohz_idle_enter(void) { }
 148static inline void tick_nohz_idle_exit(void) { }
 149
 150static inline ktime_t tick_nohz_get_sleep_length(void)
 151{
 152        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 153
 154        return len;
 155}
 156static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 157static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 158# endif /* !NO_HZ */
 159
 160# ifdef CONFIG_CPU_IDLE_GOV_MENU
 161extern void menu_hrtimer_cancel(void);
 162# else
 163static inline void menu_hrtimer_cancel(void) {}
 164# endif /* CONFIG_CPU_IDLE_GOV_MENU */
 165
 166#endif
 167
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