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
  12 #ifdef CONFIG_GENERIC_CLOCKEVENTS
  13
  14 enum tick_device_mode {
  15         TICKDEV_MODE_PERIODIC,
  16         TICKDEV_MODE_ONESHOT,
  17 };
  18
  19 struct tick_device {
  20         struct clock_event_device *evtdev;
  21         enum tick_device_mode mode;
  22 };
  23
  24 enum tick_nohz_mode {
  25         NOHZ_MODE_INACTIVE,
  26         NOHZ_MODE_LOWRES,
  27         NOHZ_MODE_HIGHRES,
  28 };
  29
  30 /**
  31  * struct tick_sched - sched tick emulation and no idle tick control/stats
  32  * @sched_timer:        hrtimer to schedule the periodic tick in high
  33  *                      resolution mode
  34  * @idle_tick:          Store the last idle tick expiry time when the tick
  35  *                      timer is modified for idle sleeps. This is necessary
  36  *                      to resume the tick timer operation in the timeline
  37  *                      when the CPU returns from idle
  38  * @tick_stopped:       Indicator that the idle tick has been stopped
  39  * @idle_jiffies:       jiffies at the entry to idle for idle time accounting
  40  * @idle_calls:         Total number of idle calls
  41  * @idle_sleeps:        Number of idle calls, where the sched tick was stopped
  42  * @idle_entrytime:     Time when the idle call was entered
  43  * @idle_waketime:      Time when the idle was interrupted
  44  * @idle_exittime:      Time when the idle state was left
  45  * @idle_sleeptime:     Sum of the time slept in idle with sched tick stopped
  46  * @iowait_sleeptime:   Sum of the time slept in idle with sched tick stopped, with IO outstanding
  47  * @sleep_length:       Duration of the current idle sleep
  48  * @do_timer_lst:       CPU was the last one doing do_timer before going idle
  49  */
  50 struct tick_sched {
  51         struct hrtimer                  sched_timer;
  52         unsigned long                   check_clocks;
  53         enum tick_nohz_mode             nohz_mode;
  54         ktime_t                         idle_tick;
  55         int                             inidle;
  56         int                             tick_stopped;
  57         unsigned long                   idle_jiffies;
  58         unsigned long                   idle_calls;
  59         unsigned long                   idle_sleeps;
  60         int                             idle_active;
  61         ktime_t                         idle_entrytime;
  62         ktime_t                         idle_waketime;
  63         ktime_t                         idle_exittime;
  64         ktime_t                         idle_sleeptime;
  65         ktime_t                         iowait_sleeptime;
  66         ktime_t                         sleep_length;
  67         unsigned long                   last_jiffies;
  68         unsigned long                   next_jiffies;
  69         ktime_t                         idle_expires;
  70         int                             do_timer_last;
  71 };
  72
  73 extern void __init tick_init(void);
  74 extern int tick_is_oneshot_available(void);
  75 extern struct tick_device *tick_get_device(int cpu);
  76
  77 # ifdef CONFIG_HIGH_RES_TIMERS
  78 extern int tick_init_highres(void);
  79 extern int tick_program_event(ktime_t expires, int force);
  80 extern void tick_setup_sched_timer(void);
  81 # endif
  82
  83 # if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
  84 extern void tick_cancel_sched_timer(int cpu);
  85 # else
  86 static inline void tick_cancel_sched_timer(int cpu) { }
  87 # endif
  88
  89 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
  90 extern struct tick_device *tick_get_broadcast_device(void);
  91 extern struct cpumask *tick_get_broadcast_mask(void);
  92
  93 #  ifdef CONFIG_TICK_ONESHOT
  94 extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
  95 #  endif
  96
  97 # endif /* BROADCAST */
  98
  99 # ifdef CONFIG_TICK_ONESHOT
 100 extern void tick_clock_notify(void);
 101 extern int tick_check_oneshot_change(int allow_nohz);
 102 extern struct tick_sched *tick_get_tick_sched(int cpu);
 103 extern void tick_check_idle(int cpu);
 104 extern int tick_oneshot_mode_active(void);
 105 #  ifndef arch_needs_cpu
 106 #   define arch_needs_cpu(cpu) (0)
 107 #  endif
 108 # else
 109 static inline void tick_clock_notify(void) { }
 110 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 111 static inline void tick_check_idle(int cpu) { }
 112 static inline int tick_oneshot_mode_active(void) { return 0; }
 113 # endif
 114
 115 #else /* CONFIG_GENERIC_CLOCKEVENTS */
 116 static inline void tick_init(void) { }
 117 static inline void tick_cancel_sched_timer(int cpu) { }
 118 static inline void tick_clock_notify(void) { }
 119 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
 120 static inline void tick_check_idle(int cpu) { }
 121 static inline int tick_oneshot_mode_active(void) { return 0; }
 122 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 123
 124 # ifdef CONFIG_NO_HZ
 125 extern void __tick_nohz_idle_enter(void);
 126 static inline void tick_nohz_idle_enter(void)
 127 {
 128         local_irq_disable();
 129         __tick_nohz_idle_enter();
 130         local_irq_enable();
 131 }
 132 extern void tick_nohz_idle_exit(void);
 133
 134 /*
 135  * Call this pair of function if the arch doesn't make any use
 136  * of RCU in-between. You won't need to call rcu_idle_enter() and
 137  * rcu_idle_exit().
 138  * Otherwise you need to call tick_nohz_idle_enter() and tick_nohz_idle_exit()
 139  * and explicitly tell RCU about the window around the place the CPU enters low
 140  * power mode where no RCU use is made. This is done by calling rcu_idle_enter()
 141  * after the last use of RCU before the CPU is put to sleep and by calling
 142  * rcu_idle_exit() before the first use of RCU after the CPU woke up.
 143  */
 144 static inline void tick_nohz_idle_enter_norcu(void)
 145 {
 146         /*
 147          * Also call rcu_idle_enter() in the irq disabled section even
 148          * if it disables irq itself.
 149          * Just an optimization that prevents from an interrupt happening
 150          * between it and __tick_nohz_idle_enter() to lose time to help
 151          * completing a grace period while we could be in extended grace
 152          * period already.
 153          */
 154         local_irq_disable();
 155         __tick_nohz_idle_enter();
 156         rcu_idle_enter();
 157         local_irq_enable();
 158 }
 159 static inline void tick_nohz_idle_exit_norcu(void)
 160 {
 161         rcu_idle_exit();
 162         tick_nohz_idle_exit();
 163 }
 164 extern void tick_nohz_irq_exit(void);
 165 extern ktime_t tick_nohz_get_sleep_length(void);
 166 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 167 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 168 # else
 169 static inline void tick_nohz_idle_enter(void) { }
 170 static inline void tick_nohz_idle_exit(void) { }
 171 static inline void tick_nohz_idle_enter_norcu(void)
 172 {
 173         rcu_idle_enter();
 174 }
 175 static inline void tick_nohz_idle_exit_norcu(void)
 176 {
 177         rcu_idle_exit();
 178 }
 179
 180 static inline ktime_t tick_nohz_get_sleep_length(void)
 181 {
 182         ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 183
 184         return len;
 185 }
 186 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 187 static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 188 # endif /* !NO_HZ */
 189
 190 #endif