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#include <linux/sched.h>
  16
  17#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
  18extern void hotplug_cpu__broadcast_tick_pull(int dead_cpu);
  19#else
  20static inline void hotplug_cpu__broadcast_tick_pull(int dead_cpu) { }
  21#endif
  22
  23#ifdef CONFIG_GENERIC_CLOCKEVENTS
  24
  25enum tick_device_mode {
  26        TICKDEV_MODE_PERIODIC,
  27        TICKDEV_MODE_ONESHOT,
  28};
  29
  30struct tick_device {
  31        struct clock_event_device *evtdev;
  32        enum tick_device_mode mode;
  33};
  34
  35enum tick_nohz_mode {
  36        NOHZ_MODE_INACTIVE,
  37        NOHZ_MODE_LOWRES,
  38        NOHZ_MODE_HIGHRES,
  39};
  40
  41/**
  42 * struct tick_sched - sched tick emulation and no idle tick control/stats
  43 * @sched_timer:        hrtimer to schedule the periodic tick in high
  44 *                      resolution mode
  45 * @last_tick:          Store the last tick expiry time when the tick
  46 *                      timer is modified for nohz sleeps. This is necessary
  47 *                      to resume the tick timer operation in the timeline
  48 *                      when the CPU returns from nohz sleep.
  49 * @next_tick:          Next tick to be fired when in dynticks mode.
  50 * @tick_stopped:       Indicator that the idle tick has been stopped
  51 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  52 * @idle_calls:         Total number of idle calls
  53 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  54 * @idle_entrytime:     Time when the idle call was entered
  55 * @idle_waketime:      Time when the idle was interrupted
  56 * @idle_exittime:      Time when the idle state was left
  57 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  58 * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
  59 * @sleep_length:       Duration of the current idle sleep
  60 * @do_timer_lst:       CPU was the last one doing do_timer before going idle
  61 */
  62struct tick_sched {
  63        struct hrtimer                  sched_timer;
  64        unsigned long                   check_clocks;
  65        enum tick_nohz_mode             nohz_mode;
  66        ktime_t                         last_tick;
  67        ktime_t                         next_tick;
  68        int                             inidle;
  69        int                             tick_stopped;
  70        unsigned long                   idle_jiffies;
  71        unsigned long                   idle_calls;
  72        unsigned long                   idle_sleeps;
  73        int                             idle_active;
  74        ktime_t                         idle_entrytime;
  75        ktime_t                         idle_waketime;
  76        ktime_t                         idle_exittime;
  77        ktime_t                         idle_sleeptime;
  78        ktime_t                         iowait_sleeptime;
  79        ktime_t                         sleep_length;
  80        unsigned long                   last_jiffies;
  81        u64                             next_timer;
  82        ktime_t                         idle_expires;
  83        int                             do_timer_last;
  84};
  85
  86extern void __init tick_init(void);
  87extern int tick_is_oneshot_available(void);
  88extern struct tick_device *tick_get_device(int cpu);
  89
  90# ifdef CONFIG_HIGH_RES_TIMERS
  91extern int tick_init_highres(void);
  92extern int tick_program_event(ktime_t expires, int force);
  93extern void tick_setup_sched_timer(void);
  94# endif
  95
  96# if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
  97extern void tick_cancel_sched_timer(int cpu);
  98# else
  99static inline void tick_cancel_sched_timer(int cpu) { }
 100# endif
 101
 102# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 103extern struct tick_device *tick_get_broadcast_device(void);
 104extern struct cpumask *tick_get_broadcast_mask(void);
 105
 106#  ifdef CONFIG_TICK_ONESHOT
 107extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
 108#  endif
 109
 110# endif /* BROADCAST */
 111
 112# ifdef CONFIG_TICK_ONESHOT
 113extern void tick_clock_notify(void);
 114extern int tick_check_oneshot_change(int allow_nohz);
 115extern struct tick_sched *tick_get_tick_sched(int cpu);
 116extern void tick_check_idle(void);
 117extern int tick_oneshot_mode_active(void);
 118#  ifndef arch_needs_cpu
 119#   define arch_needs_cpu(cpu) (0)
 120#  endif
 121# else
 122static inline void tick_clock_notify(void) { }
 123static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 124static inline void tick_check_idle(void) { }
 125static inline int tick_oneshot_mode_active(void) { return 0; }
 126# endif
 127
 128#else /* CONFIG_GENERIC_CLOCKEVENTS */
 129static inline void tick_init(void) { }
 130static inline void tick_cancel_sched_timer(int cpu) { }
 131static inline void tick_clock_notify(void) { }
 132static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 133static inline void tick_check_idle(void) { }
 134static inline int tick_oneshot_mode_active(void) { return 0; }
 135#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 136
 137# ifdef CONFIG_NO_HZ_COMMON
 138DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
 139
 140static inline int tick_nohz_tick_stopped(void)
 141{
 142        return __this_cpu_read(tick_cpu_sched.tick_stopped);
 143}
 144
 145extern void tick_nohz_idle_enter(void);
 146extern void tick_nohz_idle_exit(void);
 147extern void tick_nohz_irq_exit(void);
 148extern ktime_t tick_nohz_get_sleep_length(void);
 149extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 150extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 151
 152# else /* !CONFIG_NO_HZ_COMMON */
 153static inline int tick_nohz_tick_stopped(void)
 154{
 155        return 0;
 156}
 157
 158static inline void tick_nohz_idle_enter(void) { }
 159static inline void tick_nohz_idle_exit(void) { }
 160
 161static inline ktime_t tick_nohz_get_sleep_length(void)
 162{
 163        ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 164
 165        return len;
 166}
 167static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 168static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 169# endif /* !CONFIG_NO_HZ_COMMON */
 170
 171#ifdef CONFIG_NO_HZ_FULL
 172extern bool tick_nohz_full_running;
 173extern cpumask_var_t tick_nohz_full_mask;
 174extern cpumask_var_t housekeeping_mask;
 175
 176static inline bool tick_nohz_full_enabled(void)
 177{
 178        if (!context_tracking_is_enabled())
 179                return false;
 180
 181        return tick_nohz_full_running;
 182}
 183
 184static inline bool tick_nohz_full_cpu(int cpu)
 185{
 186        if (!tick_nohz_full_enabled())
 187                return false;
 188
 189        return cpumask_test_cpu(cpu, tick_nohz_full_mask);
 190}
 191
 192static inline int housekeeping_any_cpu(void)
 193{
 194        return cpumask_any_and(housekeeping_mask, cpu_online_mask);
 195}
 196
 197extern void tick_nohz_init(void);
 198extern void __tick_nohz_full_check(void);
 199extern void tick_nohz_full_kick(void);
 200extern void tick_nohz_full_kick_cpu(int cpu);
 201extern void tick_nohz_full_kick_all(void);
 202extern void __tick_nohz_task_switch(struct task_struct *tsk);
 203#else
 204static inline int housekeeping_any_cpu(void)
 205{
 206        return smp_processor_id();
 207}
 208
 209static inline void tick_nohz_init(void) { }
 210static inline bool tick_nohz_full_enabled(void) { return false; }
 211static inline bool tick_nohz_full_cpu(int cpu) { return false; }
 212static inline void __tick_nohz_full_check(void) { }
 213static inline void tick_nohz_full_kick_cpu(int cpu) { }
 214static inline void tick_nohz_full_kick(void) { }
 215static inline void tick_nohz_full_kick_all(void) { }
 216static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
 217#endif
 218
 219static inline bool is_housekeeping_cpu(int cpu)
 220{
 221#ifdef CONFIG_NO_HZ_FULL
 222        if (tick_nohz_full_enabled())
 223                return cpumask_test_cpu(cpu, housekeeping_mask);
 224#endif
 225        return true;
 226}
 227
 228static inline void tick_nohz_full_check(void)
 229{
 230        if (tick_nohz_full_enabled())
 231                __tick_nohz_full_check();
 232}
 233
 234static inline void tick_nohz_task_switch(struct task_struct *tsk)
 235{
 236        if (tick_nohz_full_enabled())
 237                __tick_nohz_task_switch(tsk);
 238}
 239
 240
 241#endif
 242