linux/kernel/time/tick-sched.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _TICK_SCHED_H
   3#define _TICK_SCHED_H
   4
   5#include <linux/hrtimer.h>
   6
   7enum tick_device_mode {
   8        TICKDEV_MODE_PERIODIC,
   9        TICKDEV_MODE_ONESHOT,
  10};
  11
  12struct tick_device {
  13        struct clock_event_device *evtdev;
  14        enum tick_device_mode mode;
  15};
  16
  17enum tick_nohz_mode {
  18        NOHZ_MODE_INACTIVE,
  19        NOHZ_MODE_LOWRES,
  20        NOHZ_MODE_HIGHRES,
  21};
  22
  23/**
  24 * struct tick_sched - sched tick emulation and no idle tick control/stats
  25 * @sched_timer:        hrtimer to schedule the periodic tick in high
  26 *                      resolution mode
  27 * @check_clocks:       Notification mechanism about clocksource changes
  28 * @nohz_mode:          Mode - one state of tick_nohz_mode
  29 * @inidle:             Indicator that the CPU is in the tick idle mode
  30 * @tick_stopped:       Indicator that the idle tick has been stopped
  31 * @idle_active:        Indicator that the CPU is actively in the tick idle mode;
  32 *                      it is reset during irq handling phases.
  33 * @do_timer_lst:       CPU was the last one doing do_timer before going idle
  34 * @got_idle_tick:      Tick timer function has run with @inidle set
  35 * @last_tick:          Store the last tick expiry time when the tick
  36 *                      timer is modified for nohz sleeps. This is necessary
  37 *                      to resume the tick timer operation in the timeline
  38 *                      when the CPU returns from nohz sleep.
  39 * @next_tick:          Next tick to be fired when in dynticks mode.
  40 * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  41 * @idle_calls:         Total number of idle calls
  42 * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  43 * @idle_entrytime:     Time when the idle call was entered
  44 * @idle_waketime:      Time when the idle was interrupted
  45 * @idle_exittime:      Time when the idle state was left
  46 * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  47 * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
  48 * @timer_expires:      Anticipated timer expiration time (in case sched tick is stopped)
  49 * @timer_expires_base: Base time clock monotonic for @timer_expires
  50 * @next_timer:         Expiry time of next expiring timer for debugging purpose only
  51 * @tick_dep_mask:      Tick dependency mask - is set, if someone needs the tick
  52 * @last_tick_jiffies:  Value of jiffies seen on last tick
  53 * @stalled_jiffies:    Number of stalled jiffies detected across ticks
  54 */
  55struct tick_sched {
  56        struct hrtimer                  sched_timer;
  57        unsigned long                   check_clocks;
  58        enum tick_nohz_mode             nohz_mode;
  59
  60        unsigned int                    inidle          : 1;
  61        unsigned int                    tick_stopped    : 1;
  62        unsigned int                    idle_active     : 1;
  63        unsigned int                    do_timer_last   : 1;
  64        unsigned int                    got_idle_tick   : 1;
  65
  66        ktime_t                         last_tick;
  67        ktime_t                         next_tick;
  68        unsigned long                   idle_jiffies;
  69        unsigned long                   idle_calls;
  70        unsigned long                   idle_sleeps;
  71        ktime_t                         idle_entrytime;
  72        ktime_t                         idle_waketime;
  73        ktime_t                         idle_exittime;
  74        ktime_t                         idle_sleeptime;
  75        ktime_t                         iowait_sleeptime;
  76        unsigned long                   last_jiffies;
  77        u64                             timer_expires;
  78        u64                             timer_expires_base;
  79        u64                             next_timer;
  80        ktime_t                         idle_expires;
  81        atomic_t                        tick_dep_mask;
  82        unsigned long                   last_tick_jiffies;
  83        unsigned int                    stalled_jiffies;
  84};
  85
  86extern struct tick_sched *tick_get_tick_sched(int cpu);
  87
  88extern void tick_setup_sched_timer(void);
  89#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
  90extern void tick_cancel_sched_timer(int cpu);
  91#else
  92static inline void tick_cancel_sched_timer(int cpu) { }
  93#endif
  94
  95#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  96extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
  97#else
  98static inline int
  99__tick_broadcast_oneshot_control(enum tick_broadcast_state state)
 100{
 101        return -EBUSY;
 102}
 103#endif
 104
 105#endif
 106