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#include <linux/irqflags.h>
  11#include <linux/percpu.h>
  12#include <linux/hrtimer.h>
  13#include <linux/context_tracking_state.h>
  14#include <linux/cpumask.h>
  15
  16#ifdef CONFIG_GENERIC_CLOCKEVENTS
  17
  18enum tick_device_mode {
  19        TICKDEV_MODE_PERIODIC,
  20        TICKDEV_MODE_ONESHOT,
  21};
  22
  23struct tick_device {
  24        struct clock_event_device *evtdev;
  25        enum tick_device_mode mode;
  26};
  27
  28enum tick_nohz_mode {
  29        NOHZ_MODE_INACTIVE,
  30        NOHZ_MODE_LOWRES,
  31        NOHZ_MODE_HIGHRES,
  32};
  33
  34/**
  35 * struct tick_sched - sched tick emulation and no idle tick control/stats
  36 * @sched_timer:        hrtimer to schedule the periodic tick in high
  37 *                      resolution mode
  38 * @last_tick:          Store the last tick expiry time when the tick
  39 *                      timer is modified for nohz sleeps. This is necessary
  40 *                      to resume the tick timer operation in the timeline
  41 *                      when the CPU returns from nohz sleep.
  42 * @tick_stopped:       Indicator that the idle tick has been stopped
  43 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  44 * @idle_calls:         Total number of idle calls
  45 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  46 * @idle_entrytime:     Time when the idle call was entered
  47 * @idle_waketime:      Time when the idle was interrupted
  48 * @idle_exittime:      Time when the idle state was left
  49 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  50 * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
  51 * @sleep_length:       Duration of the current idle sleep
  52 * @do_timer_lst:       CPU was the last one doing do_timer before going idle
  53 */
  54struct tick_sched {
  55        struct hrtimer                  sched_timer;
  56        unsigned long                   check_clocks;
  57        enum tick_nohz_mode             nohz_mode;
  58        ktime_t                         last_tick;
  59        int                             inidle;
  60        int                             tick_stopped;
  61        unsigned long                   idle_jiffies;
  62        unsigned long                   idle_calls;
  63        unsigned long                   idle_sleeps;
  64        int                             idle_active;
  65        ktime_t                         idle_entrytime;
  66        ktime_t                         idle_waketime;
  67        ktime_t                         idle_exittime;
  68        ktime_t                         idle_sleeptime;
  69        ktime_t                         iowait_sleeptime;
  70        ktime_t                         sleep_length;
  71        unsigned long                   last_jiffies;
  72        unsigned long                   next_jiffies;
  73        ktime_t                         idle_expires;
  74        int                             do_timer_last;
  75};
  76
  77extern void __init tick_init(void);
  78extern int tick_is_oneshot_available(void);
  79extern struct tick_device *tick_get_device(int cpu);
  80
  81# ifdef CONFIG_HIGH_RES_TIMERS
  82extern int tick_init_highres(void);
  83extern int tick_program_event(ktime_t expires, int force);
  84extern void tick_setup_sched_timer(void);
  85# endif
  86
  87# if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
  88extern void tick_cancel_sched_timer(int cpu);
  89# else
  90static inline void tick_cancel_sched_timer(int cpu) { }
  91# endif
  92
  93# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  94extern struct tick_device *tick_get_broadcast_device(void);
  95extern struct cpumask *tick_get_broadcast_mask(void);
  96
  97#  ifdef CONFIG_TICK_ONESHOT
  98extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
  99#  endif
 100
 101# endif /* BROADCAST */
 102
 103# ifdef CONFIG_TICK_ONESHOT
 104extern void tick_clock_notify(void);
 105extern int tick_check_oneshot_change(int allow_nohz);
 106extern struct tick_sched *tick_get_tick_sched(int cpu);
 107extern void tick_irq_enter(void);
 108extern int tick_oneshot_mode_active(void);
 109#  ifndef arch_needs_cpu
 110#   define arch_needs_cpu(cpu) (0)
 111#  endif
 112# else
 113static inline void tick_clock_notify(void) { }
 114static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 115static inline void tick_irq_enter(void) { }
 116static inline int tick_oneshot_mode_active(void) { return 0; }
 117# endif
 118
 119#else /* CONFIG_GENERIC_CLOCKEVENTS */
 120static inline void tick_init(void) { }
 121static inline void tick_cancel_sched_timer(int cpu) { }
 122static inline void tick_clock_notify(void) { }
 123static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 124static inline void tick_irq_enter(void) { }
 125static inline int tick_oneshot_mode_active(void) { return 0; }
 126#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 127
 128# ifdef CONFIG_NO_HZ_COMMON
 129DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
 130
 131static inline int tick_nohz_tick_stopped(void)
 132{
 133        return __this_cpu_read(tick_cpu_sched.tick_stopped);
 134}
 135
 136extern void tick_nohz_idle_enter(void);
 137extern void tick_nohz_idle_exit(void);
 138extern void tick_nohz_irq_exit(void);
 139extern ktime_t tick_nohz_get_sleep_length(void);
 140extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 141extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 142
 143# else /* !CONFIG_NO_HZ_COMMON */
 144static inline int tick_nohz_tick_stopped(void)
 145{
 146        return 0;
 147}
 148
 149static inline void tick_nohz_idle_enter(void) { }
 150static inline void tick_nohz_idle_exit(void) { }
 151
 152static inline ktime_t tick_nohz_get_sleep_length(void)
 153{
 154        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 155
 156        return len;
 157}
 158static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 159static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 160# endif /* !CONFIG_NO_HZ_COMMON */
 161
 162#ifdef CONFIG_NO_HZ_FULL
 163extern bool tick_nohz_full_running;
 164extern cpumask_var_t tick_nohz_full_mask;
 165
 166static inline bool tick_nohz_full_enabled(void)
 167{
 168        if (!context_tracking_is_enabled())
 169                return false;
 170
 171        return tick_nohz_full_running;
 172}
 173
 174static inline bool tick_nohz_full_cpu(int cpu)
 175{
 176        if (!tick_nohz_full_enabled())
 177                return false;
 178
 179        return cpumask_test_cpu(cpu, tick_nohz_full_mask);
 180}
 181
 182extern void tick_nohz_init(void);
 183extern void __tick_nohz_full_check(void);
 184extern void tick_nohz_full_kick(void);
 185extern void tick_nohz_full_kick_all(void);
 186extern void __tick_nohz_task_switch(struct task_struct *tsk);
 187#else
 188static inline void tick_nohz_init(void) { }
 189static inline bool tick_nohz_full_enabled(void) { return false; }
 190static inline bool tick_nohz_full_cpu(int cpu) { return false; }
 191static inline void __tick_nohz_full_check(void) { }
 192static inline void tick_nohz_full_kick(void) { }
 193static inline void tick_nohz_full_kick_all(void) { }
 194static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
 195#endif
 196
 197static inline void tick_nohz_full_check(void)
 198{
 199        if (tick_nohz_full_enabled())
 200                __tick_nohz_full_check();
 201}
 202
 203static inline void tick_nohz_task_switch(struct task_struct *tsk)
 204{
 205        if (tick_nohz_full_enabled())
 206                __tick_nohz_task_switch(tsk);
 207}
 208
 209
 210#endif
 211