blob: 93b8757c1ea2da118be5609392dc238dabd41152 [file] [log] [blame]
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
50 * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in softirq context
51 * 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 *
81 * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to
82 * 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#ifdef CONFIG_HIGH_RES_TIMERS
119 enum hrtimer_cb_mode cb_mode;
120 struct list_head cb_entry;
121#endif
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800122#ifdef CONFIG_TIMER_STATS
123 void *start_site;
124 char start_comm[16];
125 int start_pid;
126#endif
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800127};
128
129/**
Thomas Gleixner00362e32006-03-31 02:31:17 -0800130 * struct hrtimer_sleeper - simple sleeper structure
Thomas Gleixner00362e32006-03-31 02:31:17 -0800131 * @timer: embedded timer structure
132 * @task: task to wake up
133 *
134 * task is set to NULL, when the timer expires.
135 */
136struct hrtimer_sleeper {
137 struct hrtimer timer;
138 struct task_struct *task;
139};
140
141/**
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800142 * struct hrtimer_base - the timer base for a specific clock
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800143 * @index: clock type index for per_cpu support when moving a
144 * timer to a base on another cpu.
Thomas Gleixner92127c72006-03-26 01:38:05 -0800145 * @active: red black tree root node for the active timers
146 * @first: pointer to the timer node which expires first
147 * @resolution: the resolution of the clock, in nanoseconds
148 * @get_time: function to retrieve the current time of the clock
Martin Waitza5802902006-04-02 13:59:55 +0200149 * @get_softirq_time: function to retrieve the current time from the softirq
Thomas Gleixner92127c72006-03-26 01:38:05 -0800150 * @softirq_time: the time when running the hrtimer queue in the softirq
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800151 * @cb_pending: list of timers where the callback is pending
152 * @offset: offset of this clock to the monotonic base
153 * @reprogram: function to reprogram the timer event
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800154 */
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800155struct hrtimer_clock_base {
156 struct hrtimer_cpu_base *cpu_base;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800157 clockid_t index;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800158 struct rb_root active;
Thomas Gleixner288867e2006-01-12 11:25:54 +0100159 struct rb_node *first;
Thomas Gleixnere2787632006-01-12 11:36:14 +0100160 ktime_t resolution;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800161 ktime_t (*get_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800162 ktime_t (*get_softirq_time)(void);
Thomas Gleixner92127c72006-03-26 01:38:05 -0800163 ktime_t softirq_time;
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800164#ifdef CONFIG_HIGH_RES_TIMERS
165 ktime_t offset;
166 int (*reprogram)(struct hrtimer *t,
167 struct hrtimer_clock_base *b,
168 ktime_t n);
169#endif
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800170};
171
172#define HRTIMER_MAX_CLOCK_BASES 2
173
174/*
175 * struct hrtimer_cpu_base - the per cpu clock bases
176 * @lock: lock protecting the base and associated clock bases
177 * and timers
178 * @lock_key: the lock_class_key for use with lockdep
179 * @clock_base: array of clock bases for this cpu
180 * @curr_timer: the timer which is executing a callback right now
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800181 * @expires_next: absolute time of the next event which was scheduled
182 * via clock_set_next_event()
183 * @hres_active: State of high resolution mode
184 * @check_clocks: Indictator, when set evaluate time source and clock
185 * event devices whether high resolution mode can be
186 * activated.
187 * @cb_pending: Expired timers are moved from the rbtree to this
188 * list in the timer interrupt. The list is processed
189 * in the softirq.
190 * @nr_events: Total number of timer interrupt events
Thomas Gleixner3c8aa392007-02-16 01:27:50 -0800191 */
192struct hrtimer_cpu_base {
193 spinlock_t lock;
194 struct lock_class_key lock_key;
195 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800196#ifdef CONFIG_HIGH_RES_TIMERS
197 ktime_t expires_next;
198 int hres_active;
199 struct list_head cb_pending;
200 unsigned long nr_events;
201#endif
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800202};
203
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800204#ifdef CONFIG_HIGH_RES_TIMERS
205struct clock_event_device;
206
207extern void clock_was_set(void);
208extern void hrtimer_interrupt(struct clock_event_device *dev);
209
210/*
211 * In high resolution mode the time reference must be read accurate
212 */
213static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
214{
215 return timer->base->get_time();
216}
217
218/*
219 * The resolution of the clocks. The resolution value is returned in
220 * the clock_getres() system call to give application programmers an
221 * idea of the (in)accuracy of timers. Timer values are rounded up to
222 * this resolution values.
223 */
224# define KTIME_HIGH_RES (ktime_t) { .tv64 = 1 }
225# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
226
227#else
228
229# define KTIME_MONOTONIC_RES KTIME_LOW_RES
230
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800231/*
232 * clock_was_set() is a NOP for non- high-resolution systems. The
233 * time-sorted order guarantees that a timer does not expire early and
234 * is expired in the next softirq when the clock was advanced.
235 */
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800236static inline void clock_was_set(void) { }
237
238/*
239 * In non high resolution mode the time reference is taken from
240 * the base softirq time variable.
241 */
242static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
243{
244 return timer->base->softirq_time;
245}
246
247#endif
248
Thomas Gleixnerd316c572007-02-16 01:28:00 -0800249extern ktime_t ktime_get(void);
250extern ktime_t ktime_get_real(void);
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800251
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800252/* Exported timer functions: */
253
254/* Initialize timers: */
George Anzinger7978672c2006-02-01 03:05:11 -0800255extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
256 enum hrtimer_mode mode);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800257
258/* Basic timer operations: */
259extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
260 const enum hrtimer_mode mode);
261extern int hrtimer_cancel(struct hrtimer *timer);
262extern int hrtimer_try_to_cancel(struct hrtimer *timer);
263
Thomas Gleixnerc9cb2e32007-02-16 01:27:49 -0800264static inline int hrtimer_restart(struct hrtimer *timer)
265{
266 return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
267}
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800268
269/* Query timers: */
270extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
271extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
272
Tony Lindgren69239742006-03-06 15:42:45 -0800273extern ktime_t hrtimer_get_next_event(void);
Tony Lindgren69239742006-03-06 15:42:45 -0800274
Thomas Gleixner303e9672007-02-16 01:27:51 -0800275/*
276 * A timer is active, when it is enqueued into the rbtree or the callback
277 * function is running.
278 */
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800279static inline int hrtimer_active(const struct hrtimer *timer)
280{
Thomas Gleixner303e9672007-02-16 01:27:51 -0800281 return timer->state != HRTIMER_STATE_INACTIVE;
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800282}
283
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800284/*
285 * Helper function to check, whether the timer is on one of the queues
286 */
287static inline int hrtimer_is_queued(struct hrtimer *timer)
288{
289 return timer->state &
290 (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING);
291}
292
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800293/* Forward a hrtimer so it expires after now: */
Roman Zippel44f21472006-03-26 01:38:06 -0800294extern unsigned long
295hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800296
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800297/* Precise sleep: */
298extern long hrtimer_nanosleep(struct timespec *rqtp,
299 struct timespec __user *rmtp,
300 const enum hrtimer_mode mode,
301 const clockid_t clockid);
Toyo Abe1711ef32006-09-29 02:00:28 -0700302extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
Thomas Gleixner10c94ec2006-01-09 20:52:35 -0800303
Thomas Gleixner00362e32006-03-31 02:31:17 -0800304extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
305 struct task_struct *tsk);
306
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800307/* Soft interrupt function to run the hrtimer queues: */
308extern void hrtimer_run_queues(void);
309
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800310/* Bootup initialization: */
311extern void __init hrtimers_init(void);
312
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800313#if BITS_PER_LONG < 64
314extern unsigned long ktime_divns(const ktime_t kt, s64 div);
315#else /* BITS_PER_LONG < 64 */
316# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
317#endif
318
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800319/*
320 * Timer-statistics info:
321 */
322#ifdef CONFIG_TIMER_STATS
323
324extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
325 void *timerf, char * comm);
326
327static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
328{
329 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
330 timer->function, timer->start_comm);
331}
332
333extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
334 void *addr);
335
336static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
337{
338 __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
339}
340
341static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
342{
343 timer->start_site = NULL;
344}
345#else
346static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
347{
348}
349
350static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
351{
352}
353
354static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
355{
356}
357#endif
358
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800359#endif