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Thomas Gleixnerc0a31322006-01-09 20:52:32 -08001/*
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
Thomas Gleixner3c8aa392007-02-16 01:27:50 -080024struct hrtimer_clock_base;
25struct hrtimer_cpu_base;
26
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080027/*
28 * Mode arguments of xxx_hrtimer functions:
29 */
30enum hrtimer_mode {
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080031 HRTIMER_MODE_ABS, /* Time value is absolute */
32 HRTIMER_MODE_REL, /* Time value is relative to now */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080033};
34
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080035/*
36 * Return values for the callback function
37 */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080038enum hrtimer_restart {
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -080039 HRTIMER_NORESTART, /* Timer is not restarted */
40 HRTIMER_RESTART, /* Timer must be restarted */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080041};
42
Thomas Gleixner303e9672007-02-16 01:27:51 -080043/*
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -080044 * hrtimer callback modes:
45 *
46 * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context
47 * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context
48 * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and
49 * does not restart the timer
Andres Salomon8437fdc2007-03-06 01:42:06 -080050 * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in hardirq context
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -080051 * Special mode for tick emultation
52 */
53enum hrtimer_cb_mode {
54 HRTIMER_CB_SOFTIRQ,
55 HRTIMER_CB_IRQSAFE,
56 HRTIMER_CB_IRQSAFE_NO_RESTART,
57 HRTIMER_CB_IRQSAFE_NO_SOFTIRQ,
58};
59
60/*
61 * Values to track state of the timer
Thomas Gleixner303e9672007-02-16 01:27:51 -080062 *
63 * Possible states:
64 *
65 * 0x00 inactive
66 * 0x01 enqueued into rbtree
67 * 0x02 callback function running
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -080068 * 0x04 callback pending (high resolution mode)
69 *
70 * Special case:
Thomas Gleixner303e9672007-02-16 01:27:51 -080071 * 0x03 callback function running and enqueued
72 * (was requeued on another CPU)
Thomas Gleixner303e9672007-02-16 01:27:51 -080073 * The "callback function running and enqueued" status is only possible on
74 * SMP. It happens for example when a posix timer expired and the callback
75 * queued a signal. Between dropping the lock which protects the posix timer
76 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
77 * signal and rearm the timer. We have to preserve the callback running state,
78 * as otherwise the timer could be removed before the softirq code finishes the
79 * the handling of the timer.
80 *
Li Zefan3eb05672008-02-08 04:19:25 -080081 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
Thomas Gleixner303e9672007-02-16 01:27:51 -080082 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
83 *
84 * All state transitions are protected by cpu_base->lock.
85 */
86#define HRTIMER_STATE_INACTIVE 0x00
87#define HRTIMER_STATE_ENQUEUED 0x01
88#define HRTIMER_STATE_CALLBACK 0x02
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -080089#define HRTIMER_STATE_PENDING 0x04
Thomas Gleixner303e9672007-02-16 01:27:51 -080090
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080091/**
92 * struct hrtimer - the basic hrtimer structure
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080093 * @node: red black tree node for time ordered insertion
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080094 * @expires: the absolute expiry time in the hrtimers internal
95 * representation. The time is related to the clock on
96 * which the timer is based.
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080097 * @function: timer expiry callback function
Thomas Gleixnerc0a31322006-01-09 20:52:32 -080098 * @base: pointer to the timer base (per cpu and per clock)
Thomas Gleixner303e9672007-02-16 01:27:51 -080099 * @state: state information (See bit values above)
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800100 * @cb_mode: high resolution timer feature to select the callback execution
101 * mode
102 * @cb_entry: list head to enqueue an expired timer into the callback list
103 * @start_site: timer statistics field to store the site where the timer
104 * was started
105 * @start_comm: timer statistics field to store the name of the process which
106 * started the timer
107 * @start_pid: timer statistics field to store the pid of the task which
108 * started the timer
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800109 *
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800110 * The hrtimer structure must be initialized by hrtimer_init()
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800111 */
112struct hrtimer {
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800113 struct rb_node node;
114 ktime_t expires;
115 enum hrtimer_restart (*function)(struct hrtimer *);
116 struct hrtimer_clock_base *base;
Thomas Gleixner303e9672007-02-16 01:27:51 -0800117 unsigned long state;
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800118 enum hrtimer_cb_mode cb_mode;
119 struct list_head cb_entry;
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800120#ifdef CONFIG_TIMER_STATS
121 void *start_site;
122 char start_comm[16];
123 int start_pid;
124#endif
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800125};
126
127/**
Thomas Gleixner00362e32006-03-31 02:31:17 -0800128 * struct hrtimer_sleeper - simple sleeper structure
Thomas Gleixner00362e32006-03-31 02:31:17 -0800129 * @timer: embedded timer structure
130 * @task: task to wake up
131 *
132 * task is set to NULL, when the timer expires.
133 */
134struct hrtimer_sleeper {
135 struct hrtimer timer;
136 struct task_struct *task;
137};
138
139/**
Andres Salomond1d67172007-03-06 01:42:07 -0800140 * struct hrtimer_clock_base - the timer base for a specific clock
Randy Dunlap05fb6bf2007-02-28 20:12:13 -0800141 * @cpu_base: per cpu clock base
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800142 * @index: clock type index for per_cpu support when moving a
143 * timer to a base on another cpu.
Thomas Gleixner92127c72006-03-26 01:38:05 -0800144 * @active: red black tree root node for the active timers
145 * @first: pointer to the timer node which expires first
146 * @resolution: the resolution of the clock, in nanoseconds
147 * @get_time: function to retrieve the current time of the clock
Martin Waitza5802902006-04-02 13:59:55 +0200148 * @get_softirq_time: function to retrieve the current time from the softirq
Thomas Gleixner92127c72006-03-26 01:38:05 -0800149 * @softirq_time: the time when running the hrtimer queue in the softirq
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800150 * @offset: offset of this clock to the monotonic base
151 * @reprogram: function to reprogram the timer event
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800152 */
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800153struct hrtimer_clock_base {
154 struct hrtimer_cpu_base *cpu_base;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800155 clockid_t index;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800156 struct rb_root active;
Thomas Gleixner288867e2006-01-12 11:25:54 +0100157 struct rb_node *first;
Thomas Gleixnere2787632006-01-12 11:36:14 +0100158 ktime_t resolution;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800159 ktime_t (*get_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800160 ktime_t (*get_softirq_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800161 ktime_t softirq_time;
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800162#ifdef CONFIG_HIGH_RES_TIMERS
163 ktime_t offset;
164 int (*reprogram)(struct hrtimer *t,
165 struct hrtimer_clock_base *b,
166 ktime_t n);
167#endif
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800168};
169
170#define HRTIMER_MAX_CLOCK_BASES 2
171
172/*
173 * struct hrtimer_cpu_base - the per cpu clock bases
174 * @lock: lock protecting the base and associated clock bases
175 * and timers
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800176 * @clock_base: array of clock bases for this cpu
177 * @curr_timer: the timer which is executing a callback right now
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800178 * @expires_next: absolute time of the next event which was scheduled
179 * via clock_set_next_event()
180 * @hres_active: State of high resolution mode
181 * @check_clocks: Indictator, when set evaluate time source and clock
182 * event devices whether high resolution mode can be
183 * activated.
184 * @cb_pending: Expired timers are moved from the rbtree to this
185 * list in the timer interrupt. The list is processed
186 * in the softirq.
187 * @nr_events: Total number of timer interrupt events
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800188 */
189struct hrtimer_cpu_base {
190 spinlock_t lock;
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800191 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
Peter Zijlstrad3d74452008-01-25 21:08:31 +0100192 struct list_head cb_pending;
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800193#ifdef CONFIG_HIGH_RES_TIMERS
194 ktime_t expires_next;
195 int hres_active;
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800196 unsigned long nr_events;
197#endif
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800198};
199
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800200#ifdef CONFIG_HIGH_RES_TIMERS
201struct clock_event_device;
202
203extern void clock_was_set(void);
Ingo Molnar995f0542007-04-07 12:05:00 +0200204extern void hres_timers_resume(void);
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800205extern void hrtimer_interrupt(struct clock_event_device *dev);
206
207/*
208 * In high resolution mode the time reference must be read accurate
209 */
210static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
211{
212 return timer->base->get_time();
213}
214
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +0100215static inline int hrtimer_is_hres_active(struct hrtimer *timer)
216{
217 return timer->base->cpu_base->hres_active;
218}
219
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800220/*
221 * The resolution of the clocks. The resolution value is returned in
222 * the clock_getres() system call to give application programmers an
223 * idea of the (in)accuracy of timers. Timer values are rounded up to
224 * this resolution values.
225 */
Tony Breeds151db1f2008-02-08 09:24:52 +1100226# define HIGH_RES_NSEC 1
227# define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
228# define MONOTONIC_RES_NSEC HIGH_RES_NSEC
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800229# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
230
231#else
232
Tony Breeds151db1f2008-02-08 09:24:52 +1100233# define MONOTONIC_RES_NSEC LOW_RES_NSEC
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800234# define KTIME_MONOTONIC_RES KTIME_LOW_RES
235
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800236/*
237 * clock_was_set() is a NOP for non- high-resolution systems. The
238 * time-sorted order guarantees that a timer does not expire early and
239 * is expired in the next softirq when the clock was advanced.
240 */
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800241static inline void clock_was_set(void) { }
242
Ingo Molnar995f0542007-04-07 12:05:00 +0200243static inline void hres_timers_resume(void) { }
244
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800245/*
246 * In non high resolution mode the time reference is taken from
247 * the base softirq time variable.
248 */
249static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
250{
251 return timer->base->softirq_time;
252}
253
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +0100254static inline int hrtimer_is_hres_active(struct hrtimer *timer)
255{
256 return 0;
257}
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800258#endif
259
Thomas Gleixnerd316c572007-02-16 01:28:00 -0800260extern ktime_t ktime_get(void);
261extern ktime_t ktime_get_real(void);
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800262
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800263/* Exported timer functions: */
264
265/* Initialize timers: */
George Anzinger7978672c2006-02-01 03:05:11 -0800266extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
267 enum hrtimer_mode mode);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800268
Thomas Gleixner237fc6e2008-04-30 00:55:04 -0700269#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
270extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
271 enum hrtimer_mode mode);
272
273extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
274#else
275static inline void hrtimer_init_on_stack(struct hrtimer *timer,
276 clockid_t which_clock,
277 enum hrtimer_mode mode)
278{
279 hrtimer_init(timer, which_clock, mode);
280}
281static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
282#endif
283
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800284/* Basic timer operations: */
285extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
286 const enum hrtimer_mode mode);
287extern int hrtimer_cancel(struct hrtimer *timer);
288extern int hrtimer_try_to_cancel(struct hrtimer *timer);
289
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -0800290static inline int hrtimer_restart(struct hrtimer *timer)
291{
292 return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
293}
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800294
295/* Query timers: */
296extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
297extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
298
Tony Lindgren69239742006-03-06 15:42:45 -0800299extern ktime_t hrtimer_get_next_event(void);
Tony Lindgren69239742006-03-06 15:42:45 -0800300
Thomas Gleixner303e9672007-02-16 01:27:51 -0800301/*
302 * A timer is active, when it is enqueued into the rbtree or the callback
303 * function is running.
304 */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800305static inline int hrtimer_active(const struct hrtimer *timer)
306{
Thomas Gleixner303e9672007-02-16 01:27:51 -0800307 return timer->state != HRTIMER_STATE_INACTIVE;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800308}
309
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800310/*
311 * Helper function to check, whether the timer is on one of the queues
312 */
313static inline int hrtimer_is_queued(struct hrtimer *timer)
314{
315 return timer->state &
316 (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING);
317}
318
Oliver Hartkopp4346f652008-04-30 23:04:37 +0200319/*
320 * Helper function to check, whether the timer is running the callback
321 * function
322 */
323static inline int hrtimer_callback_running(struct hrtimer *timer)
324{
325 return timer->state & HRTIMER_STATE_CALLBACK;
326}
327
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800328/* Forward a hrtimer so it expires after now: */
Davide Libenzi4d672e72008-02-04 22:27:26 -0800329extern u64
Roman Zippel44f21472006-03-26 01:38:06 -0800330hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800331
Davide Libenzi5e05ad72008-02-04 22:27:25 -0800332/* Forward a hrtimer so it expires after the hrtimer's current now */
Davide Libenzi4d672e72008-02-04 22:27:26 -0800333static inline u64 hrtimer_forward_now(struct hrtimer *timer,
334 ktime_t interval)
Davide Libenzi5e05ad72008-02-04 22:27:25 -0800335{
336 return hrtimer_forward(timer, timer->base->get_time(), interval);
337}
338
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800339/* Precise sleep: */
340extern long hrtimer_nanosleep(struct timespec *rqtp,
Oleg Nesterov080344b2008-02-01 17:29:05 +0300341 struct timespec __user *rmtp,
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800342 const enum hrtimer_mode mode,
343 const clockid_t clockid);
Toyo Abe1711ef32006-09-29 02:00:28 -0700344extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800345
Thomas Gleixner00362e32006-03-31 02:31:17 -0800346extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
347 struct task_struct *tsk);
348
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800349/* Soft interrupt function to run the hrtimer queues: */
350extern void hrtimer_run_queues(void);
Peter Zijlstrad3d74452008-01-25 21:08:31 +0100351extern void hrtimer_run_pending(void);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800352
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800353/* Bootup initialization: */
354extern void __init hrtimers_init(void);
355
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800356#if BITS_PER_LONG < 64
Davide Libenzi4d672e72008-02-04 22:27:26 -0800357extern u64 ktime_divns(const ktime_t kt, s64 div);
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800358#else /* BITS_PER_LONG < 64 */
Davide Libenzi4d672e72008-02-04 22:27:26 -0800359# define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800360#endif
361
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800362/* Show pending timers: */
363extern void sysrq_timer_list_show(void);
364
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800365/*
366 * Timer-statistics info:
367 */
368#ifdef CONFIG_TIMER_STATS
369
370extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
Venki Pallipadic5c061b82007-07-15 23:40:30 -0700371 void *timerf, char *comm,
372 unsigned int timer_flag);
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800373
374static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
375{
376 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
Venki Pallipadic5c061b82007-07-15 23:40:30 -0700377 timer->function, timer->start_comm, 0);
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800378}
379
380extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
381 void *addr);
382
383static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
384{
385 __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
386}
387
388static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
389{
390 timer->start_site = NULL;
391}
392#else
393static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
394{
395}
396
397static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
398{
399}
400
401static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
402{
403}
404#endif
405
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800406#endif