Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.
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: #include <linux/timerqueue.h> 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: * 0x04 timer is migrated to another cpu 58: * 59: * Special cases: 60: * 0x03 callback function running and enqueued 61: * (was requeued on another CPU) 62: * 0x05 timer was migrated on CPU hotunplug 63: * 64: * The "callback function running and enqueued" status is only possible on 65: * SMP. It happens for example when a posix timer expired and the callback 66: * queued a signal. Between dropping the lock which protects the posix timer 67: * and reacquiring the base lock of the hrtimer, another CPU can deliver the 68: * signal and rearm the timer. We have to preserve the callback running state, 69: * as otherwise the timer could be removed before the softirq code finishes the 70: * the handling of the timer. 71: * 72: * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state 73: * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This 74: * also affects HRTIMER_STATE_MIGRATE where the preservation is not 75: * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is 76: * enqueued on the new cpu. 77: * 78: * All state transitions are protected by cpu_base->lock. 79: */ 80: #define HRTIMER_STATE_INACTIVE 0x00 81: #define HRTIMER_STATE_ENQUEUED 0x01 82: #define HRTIMER_STATE_CALLBACK 0x02 83: #define HRTIMER_STATE_MIGRATE 0x04 84: 85: /** 86: * struct hrtimer - the basic hrtimer structure 87: * @node: timerqueue node, which also manages node.expires, 88: * the absolute expiry time in the hrtimers internal 89: * representation. The time is related to the clock on 90: * which the timer is based. Is setup by adding 91: * slack to the _softexpires value. For non range timers 92: * identical to _softexpires. 93: * @_softexpires: the absolute earliest expiry time of the hrtimer. 94: * The time which was given as expiry time when the timer 95: * was armed. 96: * @function: timer expiry callback function 97: * @base: pointer to the timer base (per cpu and per clock) 98: * @state: state information (See bit values above) 99: * @start_site: timer statistics field to store the site where the timer 100: * was started 101: * @start_comm: timer statistics field to store the name of the process which 102: * started the timer 103: * @start_pid: timer statistics field to store the pid of the task which 104: * started the timer 105: * 106: * The hrtimer structure must be initialized by hrtimer_init() 107: */ 108: struct hrtimer { 109: struct timerqueue_node node; 110: ktime_t _softexpires; 111: enum hrtimer_restart (*function)(struct hrtimer *); 112: struct hrtimer_clock_base *base; 113: unsigned long state; 114: #ifdef CONFIG_TIMER_STATS 115: int start_pid; 116: void *start_site; 117: char start_comm[16]; 118: #endif 119: }; 120: 121: /** 122: * struct hrtimer_sleeper - simple sleeper structure 123: * @timer: embedded timer structure 124: * @task: task to wake up 125: * 126: * task is set to NULL, when the timer expires. 127: */ 128: struct hrtimer_sleeper { 129: struct hrtimer timer; 130: struct task_struct *task; 131: }; 132: 133: /** 134: * struct hrtimer_clock_base - the timer base for a specific clock 135: * @cpu_base: per cpu clock base 136: * @index: clock type index for per_cpu support when moving a 137: * timer to a base on another cpu. 138: * @clockid: clock id for per_cpu support 139: * @active: red black tree root node for the active timers 140: * @resolution: the resolution of the clock, in nanoseconds 141: * @get_time: function to retrieve the current time of the clock 142: * @softirq_time: the time when running the hrtimer queue in the softirq 143: * @offset: offset of this clock to the monotonic base 144: */ 145: struct hrtimer_clock_base { 146: struct hrtimer_cpu_base *cpu_base; 147: int index; 148: clockid_t clockid; 149: struct timerqueue_head active; 150: ktime_t resolution; 151: ktime_t (*get_time)(void); 152: ktime_t softirq_time; 153: ktime_t offset; 154: }; 155: 156: enum hrtimer_base_type { 157: HRTIMER_BASE_MONOTONIC, 158: HRTIMER_BASE_REALTIME, 159: HRTIMER_BASE_BOOTTIME, 160: HRTIMER_BASE_TAI, 161: HRTIMER_MAX_CLOCK_BASES, 162: }; 163: 164: /* 165: * struct hrtimer_cpu_base - the per cpu clock bases 166: * @lock: lock protecting the base and associated clock bases 167: * and timers 168: * @active_bases: Bitfield to mark bases with active timers 169: * @clock_was_set: Indicates that clock was set from irq context. 170: * @expires_next: absolute time of the next event which was scheduled 171: * via clock_set_next_event() 172: * @hres_active: State of high resolution mode 173: * @hang_detected: The last hrtimer interrupt detected a hang 174: * @nr_events: Total number of hrtimer interrupt events 175: * @nr_retries: Total number of hrtimer interrupt retries 176: * @nr_hangs: Total number of hrtimer interrupt hangs 177: * @max_hang_time: Maximum time spent in hrtimer_interrupt 178: * @clock_base: array of clock bases for this cpu 179: */ 180: struct hrtimer_cpu_base { 181: raw_spinlock_t lock; 182: unsigned int active_bases; 183: unsigned int clock_was_set; 184: #ifdef CONFIG_HIGH_RES_TIMERS 185: ktime_t expires_next; 186: int hres_active; 187: int hang_detected; 188: unsigned long nr_events; 189: unsigned long nr_retries; 190: unsigned long nr_hangs; 191: ktime_t max_hang_time; 192: #endif 193: struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; 194: }; 195: 196: static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) 197: { 198: timer->node.expires = time; 199: timer->_softexpires = time; 200: } 201: 202: static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) 203: { 204: timer->_softexpires = time; 205: timer->node.expires = ktime_add_safe(time, delta); 206: } 207: 208: static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta) 209: { 210: timer->_softexpires = time; 211: timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); 212: } 213: 214: static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) 215: { 216: timer->node.expires.tv64 = tv64; 217: timer->_softexpires.tv64 = tv64; 218: } 219: 220: static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) 221: { 222: timer->node.expires = ktime_add_safe(timer->node.expires, time); 223: timer->_softexpires = ktime_add_safe(timer->_softexpires, time); 224: } 225: 226: static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) 227: { 228: timer->node.expires = ktime_add_ns(timer->node.expires, ns); 229: timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); 230: } 231: 232: static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) 233: { 234: return timer->node.expires; 235: } 236: 237: static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) 238: { 239: return timer->_softexpires; 240: } 241: 242: static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) 243: { 244: return timer->node.expires.tv64; 245: } 246: static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) 247: { 248: return timer->_softexpires.tv64; 249: } 250: 251: static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) 252: { 253: return ktime_to_ns(timer->node.expires); 254: } 255: 256: static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) 257: { 258: return ktime_sub(timer->node.expires, timer->base->get_time()); 259: } 260: 261: #ifdef CONFIG_HIGH_RES_TIMERS 262: struct clock_event_device; 263: 264: extern void hrtimer_interrupt(struct clock_event_device *dev); 265: 266: /* 267: * In high resolution mode the time reference must be read accurate 268: */ 269: static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) 270: { 271: return timer->base->get_time(); 272: } 273: 274: static inline int hrtimer_is_hres_active(struct hrtimer *timer) 275: { 276: return timer->base->cpu_base->hres_active; 277: } 278: 279: extern void hrtimer_peek_ahead_timers(void); 280: 281: /* 282: * The resolution of the clocks. The resolution value is returned in 283: * the clock_getres() system call to give application programmers an 284: * idea of the (in)accuracy of timers. Timer values are rounded up to 285: * this resolution values. 286: */ 287: # define HIGH_RES_NSEC 1 288: # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } 289: # define MONOTONIC_RES_NSEC HIGH_RES_NSEC 290: # define KTIME_MONOTONIC_RES KTIME_HIGH_RES 291: 292: extern void clock_was_set_delayed(void); 293: 294: #else 295: 296: # define MONOTONIC_RES_NSEC LOW_RES_NSEC 297: # define KTIME_MONOTONIC_RES KTIME_LOW_RES 298: 299: static inline void hrtimer_peek_ahead_timers(void) { } 300: 301: /* 302: * In non high resolution mode the time reference is taken from 303: * the base softirq time variable. 304: */ 305: static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) 306: { 307: return timer->base->softirq_time; 308: } 309: 310: static inline int hrtimer_is_hres_active(struct hrtimer *timer) 311: { 312: return 0; 313: } 314: 315: static inline void clock_was_set_delayed(void) { } 316: 317: #endif 318: 319: extern void clock_was_set(void); 320: #ifdef CONFIG_TIMERFD 321: extern void timerfd_clock_was_set(void); 322: #else 323: static inline void timerfd_clock_was_set(void) { } 324: #endif 325: extern void hrtimers_resume(void); 326: 327: extern ktime_t ktime_get(void); 328: extern ktime_t ktime_get_real(void); 329: extern ktime_t ktime_get_boottime(void); 330: extern ktime_t ktime_get_monotonic_offset(void); 331: extern ktime_t ktime_get_clocktai(void); 332: extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot, 333: ktime_t *offs_tai); 334: 335: DECLARE_PER_CPU(struct tick_device, tick_cpu_device); 336: 337: 338: /* Exported timer functions: */ 339: 340: /* Initialize timers: */ 341: extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 342: enum hrtimer_mode mode); 343: 344: #ifdef CONFIG_DEBUG_OBJECTS_TIMERS 345: extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, 346: enum hrtimer_mode mode); 347: 348: extern void destroy_hrtimer_on_stack(struct hrtimer *timer); 349: #else 350: static inline void hrtimer_init_on_stack(struct hrtimer *timer, 351: clockid_t which_clock, 352: enum hrtimer_mode mode) 353: { 354: hrtimer_init(timer, which_clock, mode); 355: } 356: static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } 357: #endif 358: 359: /* Basic timer operations: */ 360: extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, 361: const enum hrtimer_mode mode); 362: extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, 363: unsigned long range_ns, const enum hrtimer_mode mode); 364: extern int 365: __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, 366: unsigned long delta_ns, 367: const enum hrtimer_mode mode, int wakeup); 368: 369: extern int hrtimer_cancel(struct hrtimer *timer); 370: extern int hrtimer_try_to_cancel(struct hrtimer *timer); 371: 372: static inline int hrtimer_start_expires(struct hrtimer *timer, 373: enum hrtimer_mode mode) 374: { 375: unsigned long delta; 376: ktime_t soft, hard; 377: soft = hrtimer_get_softexpires(timer); 378: hard = hrtimer_get_expires(timer); 379: delta = ktime_to_ns(ktime_sub(hard, soft)); 380: return hrtimer_start_range_ns(timer, soft, delta, mode); 381: } 382: 383: static inline int hrtimer_restart(struct hrtimer *timer) 384: { 385: return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); 386: } 387: 388: /* Query timers: */ 389: extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); 390: extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); 391: 392: extern ktime_t hrtimer_get_next_event(void); 393: 394: /* 395: * A timer is active, when it is enqueued into the rbtree or the 396: * callback function is running or it's in the state of being migrated 397: * to another cpu. 398: */ 399: static inline int hrtimer_active(const struct hrtimer *timer) 400: { 401: return timer->state != HRTIMER_STATE_INACTIVE; 402: } 403: 404: /* 405: * Helper function to check, whether the timer is on one of the queues 406: */ 407: static inline int hrtimer_is_queued(struct hrtimer *timer) 408: { 409: return timer->state & HRTIMER_STATE_ENQUEUED; 410: } 411: 412: /* 413: * Helper function to check, whether the timer is running the callback 414: * function 415: */ 416: static inline int hrtimer_callback_running(struct hrtimer *timer) 417: { 418: return timer->state & HRTIMER_STATE_CALLBACK; 419: } 420: 421: /* Forward a hrtimer so it expires after now: */ 422: extern u64 423: hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 424: 425: /* Forward a hrtimer so it expires after the hrtimer's current now */ 426: static inline u64 hrtimer_forward_now(struct hrtimer *timer, 427: ktime_t interval) 428: { 429: return hrtimer_forward(timer, timer->base->get_time(), interval); 430: } 431: 432: /* Precise sleep: */ 433: extern long hrtimer_nanosleep(struct timespec *rqtp, 434: struct timespec __user *rmtp, 435: const enum hrtimer_mode mode, 436: const clockid_t clockid); 437: extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); 438: 439: extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, 440: struct task_struct *tsk); 441: 442: extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, 443: const enum hrtimer_mode mode); 444: extern int schedule_hrtimeout_range_clock(ktime_t *expires, 445: unsigned long delta, const enum hrtimer_mode mode, int clock); 446: extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); 447: 448: /* Soft interrupt function to run the hrtimer queues: */ 449: extern void hrtimer_run_queues(void); 450: extern void hrtimer_run_pending(void); 451: 452: /* Bootup initialization: */ 453: extern void __init hrtimers_init(void); 454: 455: #if BITS_PER_LONG < 64 456: extern u64 ktime_divns(const ktime_t kt, s64 div); 457: #else /* BITS_PER_LONG < 64 */ 458: # define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) 459: #endif 460: 461: /* Show pending timers: */ 462: extern void sysrq_timer_list_show(void); 463: 464: #endif 465: