hrtimer.h 14.7 KB
Newer Older
1
// SPDX-License-Identifier: GPL-2.0
2 3 4 5 6 7 8 9 10 11 12 13 14
/*
 *  hrtimers - High-resolution kernel timers
 *
 *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
 *
 *  data type definitions, declarations, prototypes
 *
 *  Started by: Thomas Gleixner and Ingo Molnar
 */
#ifndef _LINUX_HRTIMER_H
#define _LINUX_HRTIMER_H

15
#include <linux/hrtimer_defs.h>
16 17 18
#include <linux/rbtree.h>
#include <linux/init.h>
#include <linux/list.h>
19
#include <linux/percpu.h>
20
#include <linux/timer.h>
21
#include <linux/timerqueue.h>
22

23 24 25
struct hrtimer_clock_base;
struct hrtimer_cpu_base;

26 27
/*
 * Mode arguments of xxx_hrtimer functions:
28 29 30 31 32
 *
 * HRTIMER_MODE_ABS		- Time value is absolute
 * HRTIMER_MODE_REL		- Time value is relative to now
 * HRTIMER_MODE_PINNED		- Timer is bound to CPU (is only considered
 *				  when starting the timer)
33 34
 * HRTIMER_MODE_SOFT		- Timer callback function will be executed in
 *				  soft irq context
35 36
 */
enum hrtimer_mode {
37 38 39
	HRTIMER_MODE_ABS	= 0x00,
	HRTIMER_MODE_REL	= 0x01,
	HRTIMER_MODE_PINNED	= 0x02,
40
	HRTIMER_MODE_SOFT	= 0x04,
41 42 43

	HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
	HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
44 45 46 47 48 49 50

	HRTIMER_MODE_ABS_SOFT	= HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
	HRTIMER_MODE_REL_SOFT	= HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,

	HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
	HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,

51 52
};

53 54 55
/*
 * Return values for the callback function
 */
56
enum hrtimer_restart {
57 58
	HRTIMER_NORESTART,	/* Timer is not restarted */
	HRTIMER_RESTART,	/* Timer must be restarted */
59 60
};

61 62
/*
 * Values to track state of the timer
63 64 65 66 67
 *
 * Possible states:
 *
 * 0x00		inactive
 * 0x01		enqueued into rbtree
68
 *
69 70 71
 * The callback state is not part of the timer->state because clearing it would
 * mean touching the timer after the callback, this makes it impossible to free
 * the timer from the callback function.
72
 *
73 74 75 76 77 78
 * Therefore we track the callback state in:
 *
 *	timer->base->cpu_base->running == timer
 *
 * On SMP it is possible to have a "callback function running and enqueued"
 * status. It happens for example when a posix timer expired and the callback
79 80
 * queued a signal. Between dropping the lock which protects the posix timer
 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
81
 * signal and rearm the timer.
82 83 84 85 86 87
 *
 * All state transitions are protected by cpu_base->lock.
 */
#define HRTIMER_STATE_INACTIVE	0x00
#define HRTIMER_STATE_ENQUEUED	0x01

88 89
/**
 * struct hrtimer - the basic hrtimer structure
90 91
 * @node:	timerqueue node, which also manages node.expires,
 *		the absolute expiry time in the hrtimers internal
92
 *		representation. The time is related to the clock on
93 94 95 96 97 98
 *		which the timer is based. Is setup by adding
 *		slack to the _softexpires value. For non range timers
 *		identical to _softexpires.
 * @_softexpires: the absolute earliest expiry time of the hrtimer.
 *		The time which was given as expiry time when the timer
 *		was armed.
99 100
 * @function:	timer expiry callback function
 * @base:	pointer to the timer base (per cpu and per clock)
101
 * @state:	state information (See bit values above)
102
 * @is_rel:	Set if the timer was armed relative
103
 * @is_soft:	Set if hrtimer will be expired in soft interrupt context.
104
 *
105
 * The hrtimer structure must be initialized by hrtimer_init()
106 107
 */
struct hrtimer {
108
	struct timerqueue_node		node;
109
	ktime_t				_softexpires;
110 111
	enum hrtimer_restart		(*function)(struct hrtimer *);
	struct hrtimer_clock_base	*base;
112 113
	u8				state;
	u8				is_rel;
114
	u8				is_soft;
115 116
};

117 118 119 120 121 122 123 124 125 126 127 128
/**
 * struct hrtimer_sleeper - simple sleeper structure
 * @timer:	embedded timer structure
 * @task:	task to wake up
 *
 * task is set to NULL, when the timer expires.
 */
struct hrtimer_sleeper {
	struct hrtimer timer;
	struct task_struct *task;
};

129
#ifdef CONFIG_64BIT
130
# define __hrtimer_clock_base_align	____cacheline_aligned
131
#else
132
# define __hrtimer_clock_base_align
133 134
#endif

135
/**
136
 * struct hrtimer_clock_base - the timer base for a specific clock
137
 * @cpu_base:		per cpu clock base
138 139
 * @index:		clock type index for per_cpu support when moving a
 *			timer to a base on another cpu.
140
 * @clockid:		clock id for per_cpu support
141 142
 * @seq:		seqcount around __run_hrtimer
 * @running:		pointer to the currently running hrtimer
143 144
 * @active:		red black tree root node for the active timers
 * @get_time:		function to retrieve the current time of the clock
145
 * @offset:		offset of this clock to the monotonic base
146
 */
147 148
struct hrtimer_clock_base {
	struct hrtimer_cpu_base	*cpu_base;
149
	unsigned int		index;
150
	clockid_t		clockid;
151 152
	seqcount_t		seq;
	struct hrtimer		*running;
153
	struct timerqueue_head	active;
154
	ktime_t			(*get_time)(void);
155
	ktime_t			offset;
156
} __hrtimer_clock_base_align;
157

158 159
enum  hrtimer_base_type {
	HRTIMER_BASE_MONOTONIC,
160
	HRTIMER_BASE_REALTIME,
161
	HRTIMER_BASE_BOOTTIME,
162
	HRTIMER_BASE_TAI,
163 164
	HRTIMER_BASE_MONOTONIC_SOFT,
	HRTIMER_BASE_REALTIME_SOFT,
165
	HRTIMER_BASE_BOOTTIME_SOFT,
166
	HRTIMER_BASE_TAI_SOFT,
167 168
	HRTIMER_MAX_CLOCK_BASES,
};
169

170
/**
171 172 173
 * struct hrtimer_cpu_base - the per cpu clock bases
 * @lock:		lock protecting the base and associated clock bases
 *			and timers
174
 * @cpu:		cpu number
175
 * @active_bases:	Bitfield to mark bases with active timers
176
 * @clock_was_set_seq:	Sequence counter of clock was set events
177
 * @hres_active:	State of high resolution mode
178
 * @in_hrtirq:		hrtimer_interrupt() is currently executing
179
 * @hang_detected:	The last hrtimer interrupt detected a hang
180 181
 * @softirq_activated:	displays, if the softirq is raised - update of softirq
 *			related settings is not required then.
182 183 184 185
 * @nr_events:		Total number of hrtimer interrupt events
 * @nr_retries:		Total number of hrtimer interrupt retries
 * @nr_hangs:		Total number of hrtimer interrupt hangs
 * @max_hang_time:	Maximum time spent in hrtimer_interrupt
186
 * @expires_next:	absolute time of the next event, is required for remote
187 188
 *			hrtimer enqueue; it is the total first expiry time (hard
 *			and soft hrtimer are taken into account)
189
 * @next_timer:		Pointer to the first expiring timer
190 191
 * @softirq_expires_next: Time to check, if soft queues needs also to be expired
 * @softirq_next_timer: Pointer to the first expiring softirq based timer
192
 * @clock_base:		array of clock bases for this cpu
193 194 195 196
 *
 * Note: next_timer is just an optimization for __remove_hrtimer().
 *	 Do not dereference the pointer because it is not reliable on
 *	 cross cpu removals.
197 198
 */
struct hrtimer_cpu_base {
199
	raw_spinlock_t			lock;
200
	unsigned int			cpu;
201
	unsigned int			active_bases;
202
	unsigned int			clock_was_set_seq;
203 204 205 206
	unsigned int			hres_active		: 1,
					in_hrtirq		: 1,
					hang_detected		: 1,
					softirq_activated       : 1;
207
#ifdef CONFIG_HIGH_RES_TIMERS
208
	unsigned int			nr_events;
209 210
	unsigned short			nr_retries;
	unsigned short			nr_hangs;
211
	unsigned int			max_hang_time;
212
#endif
213
	ktime_t				expires_next;
214
	struct hrtimer			*next_timer;
215 216
	ktime_t				softirq_expires_next;
	struct hrtimer			*softirq_next_timer;
217
	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
218
} ____cacheline_aligned;
219

220 221
static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
{
222
	timer->node.expires = time;
223
	timer->_softexpires = time;
224
}
225 226 227 228

static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
{
	timer->_softexpires = time;
229
	timer->node.expires = ktime_add_safe(time, delta);
230 231
}

232
static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
233 234
{
	timer->_softexpires = time;
235
	timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
236 237
}

238 239
static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
{
240 241
	timer->node.expires = tv64;
	timer->_softexpires = tv64;
242 243 244 245
}

static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
{
246
	timer->node.expires = ktime_add_safe(timer->node.expires, time);
247
	timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
248 249
}

250
static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
251
{
252
	timer->node.expires = ktime_add_ns(timer->node.expires, ns);
253
	timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
254 255 256 257
}

static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
{
258
	return timer->node.expires;
259 260
}

261 262 263 264 265
static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
{
	return timer->_softexpires;
}

266 267
static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
{
268
	return timer->node.expires;
269
}
270 271
static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
{
272
	return timer->_softexpires;
273
}
274 275 276

static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
{
277
	return ktime_to_ns(timer->node.expires);
278 279 280 281
}

static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
{
282
	return ktime_sub(timer->node.expires, timer->base->get_time());
283 284
}

285 286 287 288 289
static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
{
	return timer->base->get_time();
}

290 291 292 293 294 295
static inline int hrtimer_is_hres_active(struct hrtimer *timer)
{
	return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
		timer->base->cpu_base->hres_active : 0;
}

296 297 298 299 300
#ifdef CONFIG_HIGH_RES_TIMERS
struct clock_event_device;

extern void hrtimer_interrupt(struct clock_event_device *dev);

301 302
extern void clock_was_set_delayed(void);

303 304
extern unsigned int hrtimer_resolution;

305 306
#else

307
#define hrtimer_resolution	(unsigned int)LOW_RES_NSEC
308

309 310
static inline void clock_was_set_delayed(void) { }

311 312
#endif

313 314 315 316 317 318 319 320 321 322
static inline ktime_t
__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
{
	ktime_t rem = ktime_sub(timer->node.expires, now);

	/*
	 * Adjust relative timers for the extra we added in
	 * hrtimer_start_range_ns() to prevent short timeouts.
	 */
	if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
323
		rem -= hrtimer_resolution;
324 325 326 327 328 329 330 331 332 333
	return rem;
}

static inline ktime_t
hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
{
	return __hrtimer_expires_remaining_adjusted(timer,
						    timer->base->get_time());
}

334
extern void clock_was_set(void);
335 336 337 338 339
#ifdef CONFIG_TIMERFD
extern void timerfd_clock_was_set(void);
#else
static inline void timerfd_clock_was_set(void) { }
#endif
340 341
extern void hrtimers_resume(void);

342 343 344
DECLARE_PER_CPU(struct tick_device, tick_cpu_device);


345 346 347
/* Exported timer functions: */

/* Initialize timers: */
348 349
extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
			 enum hrtimer_mode mode);
350 351
extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
				 enum hrtimer_mode mode);
352

353 354 355
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
				  enum hrtimer_mode mode);
356 357 358
extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
					  clockid_t clock_id,
					  enum hrtimer_mode mode);
359 360 361 362 363 364 365 366 367

extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
#else
static inline void hrtimer_init_on_stack(struct hrtimer *timer,
					 clockid_t which_clock,
					 enum hrtimer_mode mode)
{
	hrtimer_init(timer, which_clock, mode);
}
368 369 370 371 372 373 374 375

static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
						 clockid_t clock_id,
						 enum hrtimer_mode mode)
{
	hrtimer_init_sleeper(sl, clock_id, mode);
}

376 377 378
static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
#endif

379
/* Basic timer operations: */
380
extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
381
				   u64 range_ns, const enum hrtimer_mode mode);
382

383
/**
384
 * hrtimer_start - (re)start an hrtimer
385 386
 * @timer:	the timer to be added
 * @tim:	expiry time
387
 * @mode:	timer mode: absolute (HRTIMER_MODE_ABS) or
388 389
 *		relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
 *		softirq based mode is considered for debug purpose only!
390
 */
391 392
static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
				 const enum hrtimer_mode mode)
393
{
394
	hrtimer_start_range_ns(timer, tim, 0, mode);
395 396
}

397 398 399
extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);

400 401
static inline void hrtimer_start_expires(struct hrtimer *timer,
					 enum hrtimer_mode mode)
402
{
403
	u64 delta;
404 405 406 407
	ktime_t soft, hard;
	soft = hrtimer_get_softexpires(timer);
	hard = hrtimer_get_expires(timer);
	delta = ktime_to_ns(ktime_sub(hard, soft));
408
	hrtimer_start_range_ns(timer, soft, delta, mode);
409 410
}

411
static inline void hrtimer_restart(struct hrtimer *timer)
412
{
413
	hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
414
}
415 416

/* Query timers: */
417 418 419 420 421 422
extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);

static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
{
	return __hrtimer_get_remaining(timer, false);
}
423

424
extern u64 hrtimer_get_next_event(void);
425
extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
426

427
extern bool hrtimer_active(const struct hrtimer *timer);
428

429 430 431 432 433
/*
 * Helper function to check, whether the timer is on one of the queues
 */
static inline int hrtimer_is_queued(struct hrtimer *timer)
{
434
	return timer->state & HRTIMER_STATE_ENQUEUED;
435 436
}

437 438 439 440 441 442
/*
 * Helper function to check, whether the timer is running the callback
 * function
 */
static inline int hrtimer_callback_running(struct hrtimer *timer)
{
443
	return timer->base->running == timer;
444 445
}

446
/* Forward a hrtimer so it expires after now: */
D
Davide Libenzi 已提交
447
extern u64
448
hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
449

450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465
/**
 * hrtimer_forward_now - forward the timer expiry so it expires after now
 * @timer:	hrtimer to forward
 * @interval:	the interval to forward
 *
 * Forward the timer expiry so it will expire after the current time
 * of the hrtimer clock base. Returns the number of overruns.
 *
 * Can be safely called from the callback function of @timer. If
 * called from other contexts @timer must neither be enqueued nor
 * running the callback and the caller needs to take care of
 * serialization.
 *
 * Note: This only updates the timer expiry value and does not requeue
 * the timer.
 */
D
Davide Libenzi 已提交
466 467
static inline u64 hrtimer_forward_now(struct hrtimer *timer,
				      ktime_t interval)
468 469 470 471
{
	return hrtimer_forward(timer, timer->base->get_time(), interval);
}

472
/* Precise sleep: */
473

474
extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
475
extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
476 477 478
			      const enum hrtimer_mode mode,
			      const clockid_t clockid);

479
extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
480
				    const enum hrtimer_mode mode);
481
extern int schedule_hrtimeout_range_clock(ktime_t *expires,
482 483
					  u64 delta,
					  const enum hrtimer_mode mode,
484
					  clockid_t clock_id);
485 486
extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);

487 488 489 490 491 492
/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);

/* Bootup initialization: */
extern void __init hrtimers_init(void);

493 494 495
/* Show pending timers: */
extern void sysrq_timer_list_show(void);

496 497 498 499 500 501 502
int hrtimers_prepare_cpu(unsigned int cpu);
#ifdef CONFIG_HOTPLUG_CPU
int hrtimers_dead_cpu(unsigned int cpu);
#else
#define hrtimers_dead_cpu	NULL
#endif

503
#endif
新手
引导
客服 返回
顶部