Merge branch 'cfq-2.6.33' into for-2.6.33
[linux-2.6/next.git] / include / linux / hrtimer.h
blobff037f0b1b4e07a1ce5d9e5ca06efc8be147a00c
1 /*
2 * include/linux/hrtimer.h
4 * hrtimers - High-resolution kernel timers
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
9 * data type definitions, declarations, prototypes
11 * Started by: Thomas Gleixner and Ingo Molnar
13 * For licencing details see kernel-base/COPYING
15 #ifndef _LINUX_HRTIMER_H
16 #define _LINUX_HRTIMER_H
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>
27 struct hrtimer_clock_base;
28 struct hrtimer_cpu_base;
31 * Mode arguments of xxx_hrtimer functions:
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,
42 * Return values for the callback function
44 enum hrtimer_restart {
45 HRTIMER_NORESTART, /* Timer is not restarted */
46 HRTIMER_RESTART, /* Timer must be restarted */
50 * Values to track state of the timer
52 * Possible states:
54 * 0x00 inactive
55 * 0x01 enqueued into rbtree
56 * 0x02 callback function running
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.
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.
73 * All state transitions are protected by cpu_base->lock.
75 #define HRTIMER_STATE_INACTIVE 0x00
76 #define HRTIMER_STATE_ENQUEUED 0x01
77 #define HRTIMER_STATE_CALLBACK 0x02
78 #define HRTIMER_STATE_MIGRATE 0x04
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
101 * The hrtimer structure must be initialized by hrtimer_init()
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
118 * struct hrtimer_sleeper - simple sleeper structure
119 * @timer: embedded timer structure
120 * @task: task to wake up
122 * task is set to NULL, when the timer expires.
124 struct hrtimer_sleeper {
125 struct hrtimer timer;
126 struct task_struct *task;
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
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
154 #define HRTIMER_MAX_CLOCK_BASES 2
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 * @check_clocks: Indictator, when set evaluate time source and clock
166 * event devices whether high resolution mode can be
167 * activated.
168 * @nr_events: Total number of timer interrupt events
170 struct hrtimer_cpu_base {
171 spinlock_t lock;
172 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
173 #ifdef CONFIG_HIGH_RES_TIMERS
174 ktime_t expires_next;
175 int hres_active;
176 unsigned long nr_events;
177 #endif
180 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
182 timer->_expires = time;
183 timer->_softexpires = time;
186 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
188 timer->_softexpires = time;
189 timer->_expires = ktime_add_safe(time, delta);
192 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
194 timer->_softexpires = time;
195 timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
198 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
200 timer->_expires.tv64 = tv64;
201 timer->_softexpires.tv64 = tv64;
204 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
206 timer->_expires = ktime_add_safe(timer->_expires, time);
207 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
210 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
212 timer->_expires = ktime_add_ns(timer->_expires, ns);
213 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
216 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
218 return timer->_expires;
221 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
223 return timer->_softexpires;
226 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
228 return timer->_expires.tv64;
230 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
232 return timer->_softexpires.tv64;
235 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
237 return ktime_to_ns(timer->_expires);
240 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
242 return ktime_sub(timer->_expires, timer->base->get_time());
245 #ifdef CONFIG_HIGH_RES_TIMERS
246 struct clock_event_device;
248 extern void clock_was_set(void);
249 extern void hres_timers_resume(void);
250 extern void hrtimer_interrupt(struct clock_event_device *dev);
253 * In high resolution mode the time reference must be read accurate
255 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
257 return timer->base->get_time();
260 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
262 return timer->base->cpu_base->hres_active;
265 extern void hrtimer_peek_ahead_timers(void);
268 * The resolution of the clocks. The resolution value is returned in
269 * the clock_getres() system call to give application programmers an
270 * idea of the (in)accuracy of timers. Timer values are rounded up to
271 * this resolution values.
273 # define HIGH_RES_NSEC 1
274 # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
275 # define MONOTONIC_RES_NSEC HIGH_RES_NSEC
276 # define KTIME_MONOTONIC_RES KTIME_HIGH_RES
278 #else
280 # define MONOTONIC_RES_NSEC LOW_RES_NSEC
281 # define KTIME_MONOTONIC_RES KTIME_LOW_RES
284 * clock_was_set() is a NOP for non- high-resolution systems. The
285 * time-sorted order guarantees that a timer does not expire early and
286 * is expired in the next softirq when the clock was advanced.
288 static inline void clock_was_set(void) { }
289 static inline void hrtimer_peek_ahead_timers(void) { }
291 static inline void hres_timers_resume(void) { }
294 * In non high resolution mode the time reference is taken from
295 * the base softirq time variable.
297 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
299 return timer->base->softirq_time;
302 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
304 return 0;
306 #endif
308 extern ktime_t ktime_get(void);
309 extern ktime_t ktime_get_real(void);
312 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
315 /* Exported timer functions: */
317 /* Initialize timers: */
318 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
319 enum hrtimer_mode mode);
321 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
322 extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
323 enum hrtimer_mode mode);
325 extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
326 #else
327 static inline void hrtimer_init_on_stack(struct hrtimer *timer,
328 clockid_t which_clock,
329 enum hrtimer_mode mode)
331 hrtimer_init(timer, which_clock, mode);
333 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
334 #endif
336 /* Basic timer operations: */
337 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
338 const enum hrtimer_mode mode);
339 extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
340 unsigned long range_ns, const enum hrtimer_mode mode);
341 extern int
342 __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
343 unsigned long delta_ns,
344 const enum hrtimer_mode mode, int wakeup);
346 extern int hrtimer_cancel(struct hrtimer *timer);
347 extern int hrtimer_try_to_cancel(struct hrtimer *timer);
349 static inline int hrtimer_start_expires(struct hrtimer *timer,
350 enum hrtimer_mode mode)
352 unsigned long delta;
353 ktime_t soft, hard;
354 soft = hrtimer_get_softexpires(timer);
355 hard = hrtimer_get_expires(timer);
356 delta = ktime_to_ns(ktime_sub(hard, soft));
357 return hrtimer_start_range_ns(timer, soft, delta, mode);
360 static inline int hrtimer_restart(struct hrtimer *timer)
362 return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
365 /* Query timers: */
366 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
367 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
369 extern ktime_t hrtimer_get_next_event(void);
372 * A timer is active, when it is enqueued into the rbtree or the callback
373 * function is running.
375 static inline int hrtimer_active(const struct hrtimer *timer)
377 return timer->state != HRTIMER_STATE_INACTIVE;
381 * Helper function to check, whether the timer is on one of the queues
383 static inline int hrtimer_is_queued(struct hrtimer *timer)
385 return timer->state & HRTIMER_STATE_ENQUEUED;
389 * Helper function to check, whether the timer is running the callback
390 * function
392 static inline int hrtimer_callback_running(struct hrtimer *timer)
394 return timer->state & HRTIMER_STATE_CALLBACK;
397 /* Forward a hrtimer so it expires after now: */
398 extern u64
399 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
401 /* Forward a hrtimer so it expires after the hrtimer's current now */
402 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
403 ktime_t interval)
405 return hrtimer_forward(timer, timer->base->get_time(), interval);
408 /* Precise sleep: */
409 extern long hrtimer_nanosleep(struct timespec *rqtp,
410 struct timespec __user *rmtp,
411 const enum hrtimer_mode mode,
412 const clockid_t clockid);
413 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
415 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
416 struct task_struct *tsk);
418 extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
419 const enum hrtimer_mode mode);
420 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
422 /* Soft interrupt function to run the hrtimer queues: */
423 extern void hrtimer_run_queues(void);
424 extern void hrtimer_run_pending(void);
426 /* Bootup initialization: */
427 extern void __init hrtimers_init(void);
429 #if BITS_PER_LONG < 64
430 extern u64 ktime_divns(const ktime_t kt, s64 div);
431 #else /* BITS_PER_LONG < 64 */
432 # define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
433 #endif
435 /* Show pending timers: */
436 extern void sysrq_timer_list_show(void);
439 * Timer-statistics info:
441 #ifdef CONFIG_TIMER_STATS
443 extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
444 void *timerf, char *comm,
445 unsigned int timer_flag);
447 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
449 if (likely(!timer->start_site))
450 return;
451 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
452 timer->function, timer->start_comm, 0);
455 extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
456 void *addr);
458 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
460 if (likely(!timer_stats_active))
461 return;
462 __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
465 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
467 timer->start_site = NULL;
469 #else
470 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
474 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
478 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
481 #endif
483 #endif