LCOV - code coverage report
Current view: top level - include/linux - hrtimer.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 1 1 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : /*
       2             :  *  include/linux/hrtimer.h
       3             :  *
       4             :  *  hrtimers - High-resolution kernel timers
       5             :  *
       6             :  *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
       7             :  *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
       8             :  *
       9             :  *  data type definitions, declarations, prototypes
      10             :  *
      11             :  *  Started by: Thomas Gleixner and Ingo Molnar
      12             :  *
      13             :  *  For licencing details see kernel-base/COPYING
      14             :  */
      15             : #ifndef _LINUX_HRTIMER_H
      16             : #define _LINUX_HRTIMER_H
      17             : 
      18             : #include <linux/rbtree.h>
      19             : #include <linux/ktime.h>
      20             : #include <linux/init.h>
      21             : #include <linux/list.h>
      22             : #include <linux/wait.h>
      23             : #include <linux/percpu.h>
      24             : #include <linux/timer.h>
      25             : 
      26             : 
      27             : struct hrtimer_clock_base;
      28             : struct hrtimer_cpu_base;
      29             : 
      30             : /*
      31             :  * Mode arguments of xxx_hrtimer functions:
      32             :  */
      33             : enum hrtimer_mode {
      34             :         HRTIMER_MODE_ABS = 0x0,         /* Time value is absolute */
      35             :         HRTIMER_MODE_REL = 0x1,         /* Time value is relative to now */
      36             :         HRTIMER_MODE_PINNED = 0x02,     /* Timer is bound to CPU */
      37             :         HRTIMER_MODE_ABS_PINNED = 0x02,
      38             :         HRTIMER_MODE_REL_PINNED = 0x03,
      39             : };
      40             : 
      41             : /*
      42             :  * Return values for the callback function
      43             :  */
      44             : enum hrtimer_restart {
      45             :         HRTIMER_NORESTART,      /* Timer is not restarted */
      46             :         HRTIMER_RESTART,        /* Timer must be restarted */
      47             : };
      48             : 
      49             : /*
      50             :  * Values to track state of the timer
      51             :  *
      52             :  * Possible states:
      53             :  *
      54             :  * 0x00         inactive
      55             :  * 0x01         enqueued into rbtree
      56             :  * 0x02         callback function running
      57             :  *
      58             :  * Special cases:
      59             :  * 0x03         callback function running and enqueued
      60             :  *              (was requeued on another CPU)
      61             :  * 0x09         timer was migrated on CPU hotunplug
      62             :  * The "callback function running and enqueued" status is only possible on
      63             :  * SMP. It happens for example when a posix timer expired and the callback
      64             :  * queued a signal. Between dropping the lock which protects the posix timer
      65             :  * and reacquiring the base lock of the hrtimer, another CPU can deliver the
      66             :  * signal and rearm the timer. We have to preserve the callback running state,
      67             :  * as otherwise the timer could be removed before the softirq code finishes the
      68             :  * the handling of the timer.
      69             :  *
      70             :  * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
      71             :  * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
      72             :  *
      73             :  * All state transitions are protected by cpu_base->lock.
      74             :  */
      75             : #define HRTIMER_STATE_INACTIVE  0x00
      76             : #define HRTIMER_STATE_ENQUEUED  0x01
      77             : #define HRTIMER_STATE_CALLBACK  0x02
      78             : #define HRTIMER_STATE_MIGRATE   0x04
      79             : 
      80             : /**
      81             :  * struct hrtimer - the basic hrtimer structure
      82             :  * @node:       red black tree node for time ordered insertion
      83             :  * @_expires:   the absolute expiry time in the hrtimers internal
      84             :  *              representation. The time is related to the clock on
      85             :  *              which the timer is based. Is setup by adding
      86             :  *              slack to the _softexpires value. For non range timers
      87             :  *              identical to _softexpires.
      88             :  * @_softexpires: the absolute earliest expiry time of the hrtimer.
      89             :  *              The time which was given as expiry time when the timer
      90             :  *              was armed.
      91             :  * @function:   timer expiry callback function
      92             :  * @base:       pointer to the timer base (per cpu and per clock)
      93             :  * @state:      state information (See bit values above)
      94             :  * @start_site: timer statistics field to store the site where the timer
      95             :  *              was started
      96             :  * @start_comm: timer statistics field to store the name of the process which
      97             :  *              started the timer
      98             :  * @start_pid: timer statistics field to store the pid of the task which
      99             :  *              started the timer
     100             :  *
     101             :  * The hrtimer structure must be initialized by hrtimer_init()
     102             :  */
     103             : struct hrtimer {
     104             :         struct rb_node                  node;
     105             :         ktime_t                         _expires;
     106             :         ktime_t                         _softexpires;
     107             :         enum hrtimer_restart            (*function)(struct hrtimer *);
     108             :         struct hrtimer_clock_base       *base;
     109             :         unsigned long                   state;
     110             : #ifdef CONFIG_TIMER_STATS
     111             :         int                             start_pid;
     112             :         void                            *start_site;
     113             :         char                            start_comm[16];
     114             : #endif
     115             : };
     116             : 
     117             : /**
     118             :  * struct hrtimer_sleeper - simple sleeper structure
     119             :  * @timer:      embedded timer structure
     120             :  * @task:       task to wake up
     121             :  *
     122             :  * task is set to NULL, when the timer expires.
     123             :  */
     124             : struct hrtimer_sleeper {
     125             :         struct hrtimer timer;
     126             :         struct task_struct *task;
     127             : };
     128             : 
     129             : /**
     130             :  * struct hrtimer_clock_base - the timer base for a specific clock
     131             :  * @cpu_base:           per cpu clock base
     132             :  * @index:              clock type index for per_cpu support when moving a
     133             :  *                      timer to a base on another cpu.
     134             :  * @active:             red black tree root node for the active timers
     135             :  * @first:              pointer to the timer node which expires first
     136             :  * @resolution:         the resolution of the clock, in nanoseconds
     137             :  * @get_time:           function to retrieve the current time of the clock
     138             :  * @softirq_time:       the time when running the hrtimer queue in the softirq
     139             :  * @offset:             offset of this clock to the monotonic base
     140             :  */
     141             : struct hrtimer_clock_base {
     142             :         struct hrtimer_cpu_base *cpu_base;
     143             :         clockid_t               index;
     144             :         struct rb_root          active;
     145             :         struct rb_node          *first;
     146             :         ktime_t                 resolution;
     147             :         ktime_t                 (*get_time)(void);
     148             :         ktime_t                 softirq_time;
     149             : #ifdef CONFIG_HIGH_RES_TIMERS
     150             :         ktime_t                 offset;
     151             : #endif
     152             : };
     153             : 
     154             : #define HRTIMER_MAX_CLOCK_BASES 2
     155             : 
     156             : /*
     157             :  * struct hrtimer_cpu_base - the per cpu clock bases
     158             :  * @lock:               lock protecting the base and associated clock bases
     159             :  *                      and timers
     160             :  * @clock_base:         array of clock bases for this cpu
     161             :  * @curr_timer:         the timer which is executing a callback right now
     162             :  * @expires_next:       absolute time of the next event which was scheduled
     163             :  *                      via clock_set_next_event()
     164             :  * @hres_active:        State of high resolution mode
     165             :  * @hang_detected:      The last hrtimer interrupt detected a hang
     166             :  * @nr_events:          Total number of hrtimer interrupt events
     167             :  * @nr_retries:         Total number of hrtimer interrupt retries
     168             :  * @nr_hangs:           Total number of hrtimer interrupt hangs
     169             :  * @max_hang_time:      Maximum time spent in hrtimer_interrupt
     170             :  */
     171             : struct hrtimer_cpu_base {
     172             :         raw_spinlock_t                  lock;
     173             :         struct hrtimer_clock_base       clock_base[HRTIMER_MAX_CLOCK_BASES];
     174             : #ifdef CONFIG_HIGH_RES_TIMERS
     175             :         ktime_t                         expires_next;
     176             :         int                             hres_active;
     177             :         int                             hang_detected;
     178             :         unsigned long                   nr_events;
     179             :         unsigned long                   nr_retries;
     180             :         unsigned long                   nr_hangs;
     181             :         ktime_t                         max_hang_time;
     182             : #endif
     183             : };
     184             : 
     185             : static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
     186             : {
     187             :         timer->_expires = time;
     188             :         timer->_softexpires = time;
     189             : }
     190             : 
     191             : static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
     192             : {
     193             :         timer->_softexpires = time;
     194             :         timer->_expires = ktime_add_safe(time, delta);
     195             : }
     196             : 
     197             : static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
     198             : {
     199             :         timer->_softexpires = time;
     200             :         timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
     201             : }
     202             : 
     203             : static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
     204             : {
     205             :         timer->_expires.tv64 = tv64;
     206             :         timer->_softexpires.tv64 = tv64;
     207             : }
     208             : 
     209             : static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
     210             : {
     211             :         timer->_expires = ktime_add_safe(timer->_expires, time);
     212             :         timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
     213             : }
     214             : 
     215             : static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
     216             : {
     217             :         timer->_expires = ktime_add_ns(timer->_expires, ns);
     218             :         timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
     219             : }
     220             : 
     221             : static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
     222             : {
     223             :         return timer->_expires;
     224             : }
     225             : 
     226             : static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
     227             : {
     228             :         return timer->_softexpires;
     229             : }
     230             : 
     231             : static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
     232             : {
     233             :         return timer->_expires.tv64;
     234             : }
     235             : static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
     236             : {
     237             :         return timer->_softexpires.tv64;
     238             : }
     239             : 
     240             : static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
     241             : {
     242             :         return ktime_to_ns(timer->_expires);
     243             : }
     244             : 
     245             : static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
     246             : {
     247             :     return ktime_sub(timer->_expires, timer->base->get_time());
     248             : }
     249             : 
     250             : #ifdef CONFIG_HIGH_RES_TIMERS
     251             : struct clock_event_device;
     252             : 
     253             : extern void clock_was_set(void);
     254             : extern void hres_timers_resume(void);
     255             : extern void hrtimer_interrupt(struct clock_event_device *dev);
     256             : 
     257             : /*
     258             :  * In high resolution mode the time reference must be read accurate
     259             :  */
     260             : static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
     261             : {
     262             :         return timer->base->get_time();
     263             : }
     264             : 
     265             : static inline int hrtimer_is_hres_active(struct hrtimer *timer)
     266             : {
     267             :         return timer->base->cpu_base->hres_active;
     268             : }
     269             : 
     270             : extern void hrtimer_peek_ahead_timers(void);
     271             : 
     272             : /*
     273             :  * The resolution of the clocks. The resolution value is returned in
     274             :  * the clock_getres() system call to give application programmers an
     275             :  * idea of the (in)accuracy of timers. Timer values are rounded up to
     276             :  * this resolution values.
     277             :  */
     278             : # define HIGH_RES_NSEC          1
     279             : # define KTIME_HIGH_RES         (ktime_t) { .tv64 = HIGH_RES_NSEC }
     280             : # define MONOTONIC_RES_NSEC     HIGH_RES_NSEC
     281             : # define KTIME_MONOTONIC_RES    KTIME_HIGH_RES
     282             : 
     283             : #else
     284             : 
     285             : # define MONOTONIC_RES_NSEC     LOW_RES_NSEC
     286             : # define KTIME_MONOTONIC_RES    KTIME_LOW_RES
     287             : 
     288             : /*
     289             :  * clock_was_set() is a NOP for non- high-resolution systems. The
     290             :  * time-sorted order guarantees that a timer does not expire early and
     291             :  * is expired in the next softirq when the clock was advanced.
     292             :  */
     293             : static inline void clock_was_set(void) { }
     294             : static inline void hrtimer_peek_ahead_timers(void) { }
     295             : 
     296             : static inline void hres_timers_resume(void) { }
     297             : 
     298             : /*
     299             :  * In non high resolution mode the time reference is taken from
     300             :  * the base softirq time variable.
     301             :  */
     302             : static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
     303             : {
     304             :         return timer->base->softirq_time;
     305             : }
     306             : 
     307             : static inline int hrtimer_is_hres_active(struct hrtimer *timer)
     308             : {
     309             :         return 0;
     310             : }
     311             : #endif
     312             : 
     313             : extern ktime_t ktime_get(void);
     314             : extern ktime_t ktime_get_real(void);
     315             : 
     316             : 
     317             : DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
     318             : 
     319             : 
     320             : /* Exported timer functions: */
     321             : 
     322             : /* Initialize timers: */
     323             : extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
     324             :                          enum hrtimer_mode mode);
     325             : 
     326             : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
     327             : extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
     328             :                                   enum hrtimer_mode mode);
     329             : 
     330             : extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
     331             : #else
     332             : static inline void hrtimer_init_on_stack(struct hrtimer *timer,
     333             :                                          clockid_t which_clock,
     334             :                                          enum hrtimer_mode mode)
     335             : {
     336             :         hrtimer_init(timer, which_clock, mode);
     337             : }
     338             : static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
     339             : #endif
     340             : 
     341             : /* Basic timer operations: */
     342             : extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
     343             :                          const enum hrtimer_mode mode);
     344             : extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
     345             :                         unsigned long range_ns, const enum hrtimer_mode mode);
     346             : extern int
     347             : __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
     348             :                          unsigned long delta_ns,
     349             :                          const enum hrtimer_mode mode, int wakeup);
     350             : 
     351             : extern int hrtimer_cancel(struct hrtimer *timer);
     352             : extern int hrtimer_try_to_cancel(struct hrtimer *timer);
     353             : 
     354             : static inline int hrtimer_start_expires(struct hrtimer *timer,
     355             :                                                 enum hrtimer_mode mode)
     356             : {
     357             :         unsigned long delta;
     358             :         ktime_t soft, hard;
     359             :         soft = hrtimer_get_softexpires(timer);
     360             :         hard = hrtimer_get_expires(timer);
     361             :         delta = ktime_to_ns(ktime_sub(hard, soft));
     362             :         return hrtimer_start_range_ns(timer, soft, delta, mode);
     363             : }
     364             : 
     365             : static inline int hrtimer_restart(struct hrtimer *timer)
     366             : {
     367             :         return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
     368             : }
     369             : 
     370             : /* Query timers: */
     371             : extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
     372             : extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
     373             : 
     374             : extern ktime_t hrtimer_get_next_event(void);
     375             : 
     376             : /*
     377             :  * A timer is active, when it is enqueued into the rbtree or the callback
     378             :  * function is running.
     379             :  */
     380             : static inline int hrtimer_active(const struct hrtimer *timer)
     381             : {
     382             :         return timer->state != HRTIMER_STATE_INACTIVE;
     383             : }
     384             : 
     385             : /*
     386             :  * Helper function to check, whether the timer is on one of the queues
     387             :  */
     388             : static inline int hrtimer_is_queued(struct hrtimer *timer)
     389             : {
     390             :         return timer->state & HRTIMER_STATE_ENQUEUED;
     391             : }
     392             : 
     393             : /*
     394             :  * Helper function to check, whether the timer is running the callback
     395             :  * function
     396             :  */
     397             : static inline int hrtimer_callback_running(struct hrtimer *timer)
     398             : {
     399             :         return timer->state & HRTIMER_STATE_CALLBACK;
     400             : }
     401             : 
     402             : /* Forward a hrtimer so it expires after now: */
     403             : extern u64
     404             : hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
     405             : 
     406             : /* Forward a hrtimer so it expires after the hrtimer's current now */
     407             : static inline u64 hrtimer_forward_now(struct hrtimer *timer,
     408             :                                       ktime_t interval)
     409             : {
     410             :         return hrtimer_forward(timer, timer->base->get_time(), interval);
     411             : }
     412             : 
     413             : /* Precise sleep: */
     414             : extern long hrtimer_nanosleep(struct timespec *rqtp,
     415             :                               struct timespec __user *rmtp,
     416             :                               const enum hrtimer_mode mode,
     417             :                               const clockid_t clockid);
     418             : extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
     419             : 
     420             : extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
     421             :                                  struct task_struct *tsk);
     422             : 
     423             : extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
     424             :                                                 const enum hrtimer_mode mode);
     425             : extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
     426             : 
     427             : /* Soft interrupt function to run the hrtimer queues: */
     428             : extern void hrtimer_run_queues(void);
     429             : extern void hrtimer_run_pending(void);
     430             : 
     431             : /* Bootup initialization: */
     432             : extern void __init hrtimers_init(void);
     433             : 
     434             : #if BITS_PER_LONG < 64
     435             : extern u64 ktime_divns(const ktime_t kt, s64 div);
     436             : #else /* BITS_PER_LONG < 64 */
     437             : # define ktime_divns(kt, div)           (u64)((kt).tv64 / (div))
     438             : #endif
     439             : 
     440             : /* Show pending timers: */
     441             : extern void sysrq_timer_list_show(void);
     442           1 : 
     443             : #endif

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