Merge branch 'for-linus' of git://github.com/dtor/input
[linux-btrfs-devel.git] / kernel / posix-cpu-timers.c
blobc8008dd58ef25da2d46c1563035f7a3801cfb187
1 /*
2 * Implement CPU time clocks for the POSIX clock interface.
3 */
5 #include <linux/sched.h>
6 #include <linux/posix-timers.h>
7 #include <linux/errno.h>
8 #include <linux/math64.h>
9 #include <asm/uaccess.h>
10 #include <linux/kernel_stat.h>
11 #include <trace/events/timer.h>
14 * Called after updating RLIMIT_CPU to run cpu timer and update
15 * tsk->signal->cputime_expires expiration cache if necessary. Needs
16 * siglock protection since other code may update expiration cache as
17 * well.
19 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
21 cputime_t cputime = secs_to_cputime(rlim_new);
23 spin_lock_irq(&task->sighand->siglock);
24 set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
25 spin_unlock_irq(&task->sighand->siglock);
28 static int check_clock(const clockid_t which_clock)
30 int error = 0;
31 struct task_struct *p;
32 const pid_t pid = CPUCLOCK_PID(which_clock);
34 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
35 return -EINVAL;
37 if (pid == 0)
38 return 0;
40 rcu_read_lock();
41 p = find_task_by_vpid(pid);
42 if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
43 same_thread_group(p, current) : has_group_leader_pid(p))) {
44 error = -EINVAL;
46 rcu_read_unlock();
48 return error;
51 static inline union cpu_time_count
52 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
54 union cpu_time_count ret;
55 ret.sched = 0; /* high half always zero when .cpu used */
56 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
57 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
58 } else {
59 ret.cpu = timespec_to_cputime(tp);
61 return ret;
64 static void sample_to_timespec(const clockid_t which_clock,
65 union cpu_time_count cpu,
66 struct timespec *tp)
68 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
69 *tp = ns_to_timespec(cpu.sched);
70 else
71 cputime_to_timespec(cpu.cpu, tp);
74 static inline int cpu_time_before(const clockid_t which_clock,
75 union cpu_time_count now,
76 union cpu_time_count then)
78 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
79 return now.sched < then.sched;
80 } else {
81 return cputime_lt(now.cpu, then.cpu);
84 static inline void cpu_time_add(const clockid_t which_clock,
85 union cpu_time_count *acc,
86 union cpu_time_count val)
88 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
89 acc->sched += val.sched;
90 } else {
91 acc->cpu = cputime_add(acc->cpu, val.cpu);
94 static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
95 union cpu_time_count a,
96 union cpu_time_count b)
98 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
99 a.sched -= b.sched;
100 } else {
101 a.cpu = cputime_sub(a.cpu, b.cpu);
103 return a;
107 * Divide and limit the result to res >= 1
109 * This is necessary to prevent signal delivery starvation, when the result of
110 * the division would be rounded down to 0.
112 static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
114 cputime_t res = cputime_div(time, div);
116 return max_t(cputime_t, res, 1);
120 * Update expiry time from increment, and increase overrun count,
121 * given the current clock sample.
123 static void bump_cpu_timer(struct k_itimer *timer,
124 union cpu_time_count now)
126 int i;
128 if (timer->it.cpu.incr.sched == 0)
129 return;
131 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
132 unsigned long long delta, incr;
134 if (now.sched < timer->it.cpu.expires.sched)
135 return;
136 incr = timer->it.cpu.incr.sched;
137 delta = now.sched + incr - timer->it.cpu.expires.sched;
138 /* Don't use (incr*2 < delta), incr*2 might overflow. */
139 for (i = 0; incr < delta - incr; i++)
140 incr = incr << 1;
141 for (; i >= 0; incr >>= 1, i--) {
142 if (delta < incr)
143 continue;
144 timer->it.cpu.expires.sched += incr;
145 timer->it_overrun += 1 << i;
146 delta -= incr;
148 } else {
149 cputime_t delta, incr;
151 if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
152 return;
153 incr = timer->it.cpu.incr.cpu;
154 delta = cputime_sub(cputime_add(now.cpu, incr),
155 timer->it.cpu.expires.cpu);
156 /* Don't use (incr*2 < delta), incr*2 might overflow. */
157 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
158 incr = cputime_add(incr, incr);
159 for (; i >= 0; incr = cputime_halve(incr), i--) {
160 if (cputime_lt(delta, incr))
161 continue;
162 timer->it.cpu.expires.cpu =
163 cputime_add(timer->it.cpu.expires.cpu, incr);
164 timer->it_overrun += 1 << i;
165 delta = cputime_sub(delta, incr);
170 static inline cputime_t prof_ticks(struct task_struct *p)
172 return cputime_add(p->utime, p->stime);
174 static inline cputime_t virt_ticks(struct task_struct *p)
176 return p->utime;
179 static int
180 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
182 int error = check_clock(which_clock);
183 if (!error) {
184 tp->tv_sec = 0;
185 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
186 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
188 * If sched_clock is using a cycle counter, we
189 * don't have any idea of its true resolution
190 * exported, but it is much more than 1s/HZ.
192 tp->tv_nsec = 1;
195 return error;
198 static int
199 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
202 * You can never reset a CPU clock, but we check for other errors
203 * in the call before failing with EPERM.
205 int error = check_clock(which_clock);
206 if (error == 0) {
207 error = -EPERM;
209 return error;
214 * Sample a per-thread clock for the given task.
216 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
217 union cpu_time_count *cpu)
219 switch (CPUCLOCK_WHICH(which_clock)) {
220 default:
221 return -EINVAL;
222 case CPUCLOCK_PROF:
223 cpu->cpu = prof_ticks(p);
224 break;
225 case CPUCLOCK_VIRT:
226 cpu->cpu = virt_ticks(p);
227 break;
228 case CPUCLOCK_SCHED:
229 cpu->sched = task_sched_runtime(p);
230 break;
232 return 0;
235 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
237 struct signal_struct *sig = tsk->signal;
238 struct task_struct *t;
240 times->utime = sig->utime;
241 times->stime = sig->stime;
242 times->sum_exec_runtime = sig->sum_sched_runtime;
244 rcu_read_lock();
245 /* make sure we can trust tsk->thread_group list */
246 if (!likely(pid_alive(tsk)))
247 goto out;
249 t = tsk;
250 do {
251 times->utime = cputime_add(times->utime, t->utime);
252 times->stime = cputime_add(times->stime, t->stime);
253 times->sum_exec_runtime += task_sched_runtime(t);
254 } while_each_thread(tsk, t);
255 out:
256 rcu_read_unlock();
259 static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
261 if (cputime_gt(b->utime, a->utime))
262 a->utime = b->utime;
264 if (cputime_gt(b->stime, a->stime))
265 a->stime = b->stime;
267 if (b->sum_exec_runtime > a->sum_exec_runtime)
268 a->sum_exec_runtime = b->sum_exec_runtime;
271 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
273 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
274 struct task_cputime sum;
275 unsigned long flags;
277 spin_lock_irqsave(&cputimer->lock, flags);
278 if (!cputimer->running) {
279 cputimer->running = 1;
281 * The POSIX timer interface allows for absolute time expiry
282 * values through the TIMER_ABSTIME flag, therefore we have
283 * to synchronize the timer to the clock every time we start
284 * it.
286 thread_group_cputime(tsk, &sum);
287 update_gt_cputime(&cputimer->cputime, &sum);
289 *times = cputimer->cputime;
290 spin_unlock_irqrestore(&cputimer->lock, flags);
294 * Sample a process (thread group) clock for the given group_leader task.
295 * Must be called with tasklist_lock held for reading.
297 static int cpu_clock_sample_group(const clockid_t which_clock,
298 struct task_struct *p,
299 union cpu_time_count *cpu)
301 struct task_cputime cputime;
303 switch (CPUCLOCK_WHICH(which_clock)) {
304 default:
305 return -EINVAL;
306 case CPUCLOCK_PROF:
307 thread_group_cputime(p, &cputime);
308 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
309 break;
310 case CPUCLOCK_VIRT:
311 thread_group_cputime(p, &cputime);
312 cpu->cpu = cputime.utime;
313 break;
314 case CPUCLOCK_SCHED:
315 thread_group_cputime(p, &cputime);
316 cpu->sched = cputime.sum_exec_runtime;
317 break;
319 return 0;
323 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
325 const pid_t pid = CPUCLOCK_PID(which_clock);
326 int error = -EINVAL;
327 union cpu_time_count rtn;
329 if (pid == 0) {
331 * Special case constant value for our own clocks.
332 * We don't have to do any lookup to find ourselves.
334 if (CPUCLOCK_PERTHREAD(which_clock)) {
336 * Sampling just ourselves we can do with no locking.
338 error = cpu_clock_sample(which_clock,
339 current, &rtn);
340 } else {
341 read_lock(&tasklist_lock);
342 error = cpu_clock_sample_group(which_clock,
343 current, &rtn);
344 read_unlock(&tasklist_lock);
346 } else {
348 * Find the given PID, and validate that the caller
349 * should be able to see it.
351 struct task_struct *p;
352 rcu_read_lock();
353 p = find_task_by_vpid(pid);
354 if (p) {
355 if (CPUCLOCK_PERTHREAD(which_clock)) {
356 if (same_thread_group(p, current)) {
357 error = cpu_clock_sample(which_clock,
358 p, &rtn);
360 } else {
361 read_lock(&tasklist_lock);
362 if (thread_group_leader(p) && p->sighand) {
363 error =
364 cpu_clock_sample_group(which_clock,
365 p, &rtn);
367 read_unlock(&tasklist_lock);
370 rcu_read_unlock();
373 if (error)
374 return error;
375 sample_to_timespec(which_clock, rtn, tp);
376 return 0;
381 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
382 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
383 * new timer already all-zeros initialized.
385 static int posix_cpu_timer_create(struct k_itimer *new_timer)
387 int ret = 0;
388 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
389 struct task_struct *p;
391 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
392 return -EINVAL;
394 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
396 rcu_read_lock();
397 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
398 if (pid == 0) {
399 p = current;
400 } else {
401 p = find_task_by_vpid(pid);
402 if (p && !same_thread_group(p, current))
403 p = NULL;
405 } else {
406 if (pid == 0) {
407 p = current->group_leader;
408 } else {
409 p = find_task_by_vpid(pid);
410 if (p && !has_group_leader_pid(p))
411 p = NULL;
414 new_timer->it.cpu.task = p;
415 if (p) {
416 get_task_struct(p);
417 } else {
418 ret = -EINVAL;
420 rcu_read_unlock();
422 return ret;
426 * Clean up a CPU-clock timer that is about to be destroyed.
427 * This is called from timer deletion with the timer already locked.
428 * If we return TIMER_RETRY, it's necessary to release the timer's lock
429 * and try again. (This happens when the timer is in the middle of firing.)
431 static int posix_cpu_timer_del(struct k_itimer *timer)
433 struct task_struct *p = timer->it.cpu.task;
434 int ret = 0;
436 if (likely(p != NULL)) {
437 read_lock(&tasklist_lock);
438 if (unlikely(p->sighand == NULL)) {
440 * We raced with the reaping of the task.
441 * The deletion should have cleared us off the list.
443 BUG_ON(!list_empty(&timer->it.cpu.entry));
444 } else {
445 spin_lock(&p->sighand->siglock);
446 if (timer->it.cpu.firing)
447 ret = TIMER_RETRY;
448 else
449 list_del(&timer->it.cpu.entry);
450 spin_unlock(&p->sighand->siglock);
452 read_unlock(&tasklist_lock);
454 if (!ret)
455 put_task_struct(p);
458 return ret;
462 * Clean out CPU timers still ticking when a thread exited. The task
463 * pointer is cleared, and the expiry time is replaced with the residual
464 * time for later timer_gettime calls to return.
465 * This must be called with the siglock held.
467 static void cleanup_timers(struct list_head *head,
468 cputime_t utime, cputime_t stime,
469 unsigned long long sum_exec_runtime)
471 struct cpu_timer_list *timer, *next;
472 cputime_t ptime = cputime_add(utime, stime);
474 list_for_each_entry_safe(timer, next, head, entry) {
475 list_del_init(&timer->entry);
476 if (cputime_lt(timer->expires.cpu, ptime)) {
477 timer->expires.cpu = cputime_zero;
478 } else {
479 timer->expires.cpu = cputime_sub(timer->expires.cpu,
480 ptime);
484 ++head;
485 list_for_each_entry_safe(timer, next, head, entry) {
486 list_del_init(&timer->entry);
487 if (cputime_lt(timer->expires.cpu, utime)) {
488 timer->expires.cpu = cputime_zero;
489 } else {
490 timer->expires.cpu = cputime_sub(timer->expires.cpu,
491 utime);
495 ++head;
496 list_for_each_entry_safe(timer, next, head, entry) {
497 list_del_init(&timer->entry);
498 if (timer->expires.sched < sum_exec_runtime) {
499 timer->expires.sched = 0;
500 } else {
501 timer->expires.sched -= sum_exec_runtime;
507 * These are both called with the siglock held, when the current thread
508 * is being reaped. When the final (leader) thread in the group is reaped,
509 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
511 void posix_cpu_timers_exit(struct task_struct *tsk)
513 cleanup_timers(tsk->cpu_timers,
514 tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
517 void posix_cpu_timers_exit_group(struct task_struct *tsk)
519 struct signal_struct *const sig = tsk->signal;
521 cleanup_timers(tsk->signal->cpu_timers,
522 cputime_add(tsk->utime, sig->utime),
523 cputime_add(tsk->stime, sig->stime),
524 tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
527 static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
530 * That's all for this thread or process.
531 * We leave our residual in expires to be reported.
533 put_task_struct(timer->it.cpu.task);
534 timer->it.cpu.task = NULL;
535 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
536 timer->it.cpu.expires,
537 now);
540 static inline int expires_gt(cputime_t expires, cputime_t new_exp)
542 return cputime_eq(expires, cputime_zero) ||
543 cputime_gt(expires, new_exp);
547 * Insert the timer on the appropriate list before any timers that
548 * expire later. This must be called with the tasklist_lock held
549 * for reading, interrupts disabled and p->sighand->siglock taken.
551 static void arm_timer(struct k_itimer *timer)
553 struct task_struct *p = timer->it.cpu.task;
554 struct list_head *head, *listpos;
555 struct task_cputime *cputime_expires;
556 struct cpu_timer_list *const nt = &timer->it.cpu;
557 struct cpu_timer_list *next;
559 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
560 head = p->cpu_timers;
561 cputime_expires = &p->cputime_expires;
562 } else {
563 head = p->signal->cpu_timers;
564 cputime_expires = &p->signal->cputime_expires;
566 head += CPUCLOCK_WHICH(timer->it_clock);
568 listpos = head;
569 list_for_each_entry(next, head, entry) {
570 if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
571 break;
572 listpos = &next->entry;
574 list_add(&nt->entry, listpos);
576 if (listpos == head) {
577 union cpu_time_count *exp = &nt->expires;
580 * We are the new earliest-expiring POSIX 1.b timer, hence
581 * need to update expiration cache. Take into account that
582 * for process timers we share expiration cache with itimers
583 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
586 switch (CPUCLOCK_WHICH(timer->it_clock)) {
587 case CPUCLOCK_PROF:
588 if (expires_gt(cputime_expires->prof_exp, exp->cpu))
589 cputime_expires->prof_exp = exp->cpu;
590 break;
591 case CPUCLOCK_VIRT:
592 if (expires_gt(cputime_expires->virt_exp, exp->cpu))
593 cputime_expires->virt_exp = exp->cpu;
594 break;
595 case CPUCLOCK_SCHED:
596 if (cputime_expires->sched_exp == 0 ||
597 cputime_expires->sched_exp > exp->sched)
598 cputime_expires->sched_exp = exp->sched;
599 break;
605 * The timer is locked, fire it and arrange for its reload.
607 static void cpu_timer_fire(struct k_itimer *timer)
609 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
611 * User don't want any signal.
613 timer->it.cpu.expires.sched = 0;
614 } else if (unlikely(timer->sigq == NULL)) {
616 * This a special case for clock_nanosleep,
617 * not a normal timer from sys_timer_create.
619 wake_up_process(timer->it_process);
620 timer->it.cpu.expires.sched = 0;
621 } else if (timer->it.cpu.incr.sched == 0) {
623 * One-shot timer. Clear it as soon as it's fired.
625 posix_timer_event(timer, 0);
626 timer->it.cpu.expires.sched = 0;
627 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
629 * The signal did not get queued because the signal
630 * was ignored, so we won't get any callback to
631 * reload the timer. But we need to keep it
632 * ticking in case the signal is deliverable next time.
634 posix_cpu_timer_schedule(timer);
639 * Sample a process (thread group) timer for the given group_leader task.
640 * Must be called with tasklist_lock held for reading.
642 static int cpu_timer_sample_group(const clockid_t which_clock,
643 struct task_struct *p,
644 union cpu_time_count *cpu)
646 struct task_cputime cputime;
648 thread_group_cputimer(p, &cputime);
649 switch (CPUCLOCK_WHICH(which_clock)) {
650 default:
651 return -EINVAL;
652 case CPUCLOCK_PROF:
653 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
654 break;
655 case CPUCLOCK_VIRT:
656 cpu->cpu = cputime.utime;
657 break;
658 case CPUCLOCK_SCHED:
659 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
660 break;
662 return 0;
666 * Guts of sys_timer_settime for CPU timers.
667 * This is called with the timer locked and interrupts disabled.
668 * If we return TIMER_RETRY, it's necessary to release the timer's lock
669 * and try again. (This happens when the timer is in the middle of firing.)
671 static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
672 struct itimerspec *new, struct itimerspec *old)
674 struct task_struct *p = timer->it.cpu.task;
675 union cpu_time_count old_expires, new_expires, old_incr, val;
676 int ret;
678 if (unlikely(p == NULL)) {
680 * Timer refers to a dead task's clock.
682 return -ESRCH;
685 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
687 read_lock(&tasklist_lock);
689 * We need the tasklist_lock to protect against reaping that
690 * clears p->sighand. If p has just been reaped, we can no
691 * longer get any information about it at all.
693 if (unlikely(p->sighand == NULL)) {
694 read_unlock(&tasklist_lock);
695 put_task_struct(p);
696 timer->it.cpu.task = NULL;
697 return -ESRCH;
701 * Disarm any old timer after extracting its expiry time.
703 BUG_ON(!irqs_disabled());
705 ret = 0;
706 old_incr = timer->it.cpu.incr;
707 spin_lock(&p->sighand->siglock);
708 old_expires = timer->it.cpu.expires;
709 if (unlikely(timer->it.cpu.firing)) {
710 timer->it.cpu.firing = -1;
711 ret = TIMER_RETRY;
712 } else
713 list_del_init(&timer->it.cpu.entry);
716 * We need to sample the current value to convert the new
717 * value from to relative and absolute, and to convert the
718 * old value from absolute to relative. To set a process
719 * timer, we need a sample to balance the thread expiry
720 * times (in arm_timer). With an absolute time, we must
721 * check if it's already passed. In short, we need a sample.
723 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
724 cpu_clock_sample(timer->it_clock, p, &val);
725 } else {
726 cpu_timer_sample_group(timer->it_clock, p, &val);
729 if (old) {
730 if (old_expires.sched == 0) {
731 old->it_value.tv_sec = 0;
732 old->it_value.tv_nsec = 0;
733 } else {
735 * Update the timer in case it has
736 * overrun already. If it has,
737 * we'll report it as having overrun
738 * and with the next reloaded timer
739 * already ticking, though we are
740 * swallowing that pending
741 * notification here to install the
742 * new setting.
744 bump_cpu_timer(timer, val);
745 if (cpu_time_before(timer->it_clock, val,
746 timer->it.cpu.expires)) {
747 old_expires = cpu_time_sub(
748 timer->it_clock,
749 timer->it.cpu.expires, val);
750 sample_to_timespec(timer->it_clock,
751 old_expires,
752 &old->it_value);
753 } else {
754 old->it_value.tv_nsec = 1;
755 old->it_value.tv_sec = 0;
760 if (unlikely(ret)) {
762 * We are colliding with the timer actually firing.
763 * Punt after filling in the timer's old value, and
764 * disable this firing since we are already reporting
765 * it as an overrun (thanks to bump_cpu_timer above).
767 spin_unlock(&p->sighand->siglock);
768 read_unlock(&tasklist_lock);
769 goto out;
772 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
773 cpu_time_add(timer->it_clock, &new_expires, val);
777 * Install the new expiry time (or zero).
778 * For a timer with no notification action, we don't actually
779 * arm the timer (we'll just fake it for timer_gettime).
781 timer->it.cpu.expires = new_expires;
782 if (new_expires.sched != 0 &&
783 cpu_time_before(timer->it_clock, val, new_expires)) {
784 arm_timer(timer);
787 spin_unlock(&p->sighand->siglock);
788 read_unlock(&tasklist_lock);
791 * Install the new reload setting, and
792 * set up the signal and overrun bookkeeping.
794 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
795 &new->it_interval);
798 * This acts as a modification timestamp for the timer,
799 * so any automatic reload attempt will punt on seeing
800 * that we have reset the timer manually.
802 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
803 ~REQUEUE_PENDING;
804 timer->it_overrun_last = 0;
805 timer->it_overrun = -1;
807 if (new_expires.sched != 0 &&
808 !cpu_time_before(timer->it_clock, val, new_expires)) {
810 * The designated time already passed, so we notify
811 * immediately, even if the thread never runs to
812 * accumulate more time on this clock.
814 cpu_timer_fire(timer);
817 ret = 0;
818 out:
819 if (old) {
820 sample_to_timespec(timer->it_clock,
821 old_incr, &old->it_interval);
823 return ret;
826 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
828 union cpu_time_count now;
829 struct task_struct *p = timer->it.cpu.task;
830 int clear_dead;
833 * Easy part: convert the reload time.
835 sample_to_timespec(timer->it_clock,
836 timer->it.cpu.incr, &itp->it_interval);
838 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
839 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
840 return;
843 if (unlikely(p == NULL)) {
845 * This task already died and the timer will never fire.
846 * In this case, expires is actually the dead value.
848 dead:
849 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
850 &itp->it_value);
851 return;
855 * Sample the clock to take the difference with the expiry time.
857 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
858 cpu_clock_sample(timer->it_clock, p, &now);
859 clear_dead = p->exit_state;
860 } else {
861 read_lock(&tasklist_lock);
862 if (unlikely(p->sighand == NULL)) {
864 * The process has been reaped.
865 * We can't even collect a sample any more.
866 * Call the timer disarmed, nothing else to do.
868 put_task_struct(p);
869 timer->it.cpu.task = NULL;
870 timer->it.cpu.expires.sched = 0;
871 read_unlock(&tasklist_lock);
872 goto dead;
873 } else {
874 cpu_timer_sample_group(timer->it_clock, p, &now);
875 clear_dead = (unlikely(p->exit_state) &&
876 thread_group_empty(p));
878 read_unlock(&tasklist_lock);
881 if (unlikely(clear_dead)) {
883 * We've noticed that the thread is dead, but
884 * not yet reaped. Take this opportunity to
885 * drop our task ref.
887 clear_dead_task(timer, now);
888 goto dead;
891 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
892 sample_to_timespec(timer->it_clock,
893 cpu_time_sub(timer->it_clock,
894 timer->it.cpu.expires, now),
895 &itp->it_value);
896 } else {
898 * The timer should have expired already, but the firing
899 * hasn't taken place yet. Say it's just about to expire.
901 itp->it_value.tv_nsec = 1;
902 itp->it_value.tv_sec = 0;
907 * Check for any per-thread CPU timers that have fired and move them off
908 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
909 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
911 static void check_thread_timers(struct task_struct *tsk,
912 struct list_head *firing)
914 int maxfire;
915 struct list_head *timers = tsk->cpu_timers;
916 struct signal_struct *const sig = tsk->signal;
917 unsigned long soft;
919 maxfire = 20;
920 tsk->cputime_expires.prof_exp = cputime_zero;
921 while (!list_empty(timers)) {
922 struct cpu_timer_list *t = list_first_entry(timers,
923 struct cpu_timer_list,
924 entry);
925 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
926 tsk->cputime_expires.prof_exp = t->expires.cpu;
927 break;
929 t->firing = 1;
930 list_move_tail(&t->entry, firing);
933 ++timers;
934 maxfire = 20;
935 tsk->cputime_expires.virt_exp = cputime_zero;
936 while (!list_empty(timers)) {
937 struct cpu_timer_list *t = list_first_entry(timers,
938 struct cpu_timer_list,
939 entry);
940 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
941 tsk->cputime_expires.virt_exp = t->expires.cpu;
942 break;
944 t->firing = 1;
945 list_move_tail(&t->entry, firing);
948 ++timers;
949 maxfire = 20;
950 tsk->cputime_expires.sched_exp = 0;
951 while (!list_empty(timers)) {
952 struct cpu_timer_list *t = list_first_entry(timers,
953 struct cpu_timer_list,
954 entry);
955 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
956 tsk->cputime_expires.sched_exp = t->expires.sched;
957 break;
959 t->firing = 1;
960 list_move_tail(&t->entry, firing);
964 * Check for the special case thread timers.
966 soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
967 if (soft != RLIM_INFINITY) {
968 unsigned long hard =
969 ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
971 if (hard != RLIM_INFINITY &&
972 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
974 * At the hard limit, we just die.
975 * No need to calculate anything else now.
977 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
978 return;
980 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
982 * At the soft limit, send a SIGXCPU every second.
984 if (soft < hard) {
985 soft += USEC_PER_SEC;
986 sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
988 printk(KERN_INFO
989 "RT Watchdog Timeout: %s[%d]\n",
990 tsk->comm, task_pid_nr(tsk));
991 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
996 static void stop_process_timers(struct signal_struct *sig)
998 struct thread_group_cputimer *cputimer = &sig->cputimer;
999 unsigned long flags;
1001 spin_lock_irqsave(&cputimer->lock, flags);
1002 cputimer->running = 0;
1003 spin_unlock_irqrestore(&cputimer->lock, flags);
1006 static u32 onecputick;
1008 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
1009 cputime_t *expires, cputime_t cur_time, int signo)
1011 if (cputime_eq(it->expires, cputime_zero))
1012 return;
1014 if (cputime_ge(cur_time, it->expires)) {
1015 if (!cputime_eq(it->incr, cputime_zero)) {
1016 it->expires = cputime_add(it->expires, it->incr);
1017 it->error += it->incr_error;
1018 if (it->error >= onecputick) {
1019 it->expires = cputime_sub(it->expires,
1020 cputime_one_jiffy);
1021 it->error -= onecputick;
1023 } else {
1024 it->expires = cputime_zero;
1027 trace_itimer_expire(signo == SIGPROF ?
1028 ITIMER_PROF : ITIMER_VIRTUAL,
1029 tsk->signal->leader_pid, cur_time);
1030 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
1033 if (!cputime_eq(it->expires, cputime_zero) &&
1034 (cputime_eq(*expires, cputime_zero) ||
1035 cputime_lt(it->expires, *expires))) {
1036 *expires = it->expires;
1041 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1043 * @cputime: The struct to compare.
1045 * Checks @cputime to see if all fields are zero. Returns true if all fields
1046 * are zero, false if any field is nonzero.
1048 static inline int task_cputime_zero(const struct task_cputime *cputime)
1050 if (cputime_eq(cputime->utime, cputime_zero) &&
1051 cputime_eq(cputime->stime, cputime_zero) &&
1052 cputime->sum_exec_runtime == 0)
1053 return 1;
1054 return 0;
1058 * Check for any per-thread CPU timers that have fired and move them
1059 * off the tsk->*_timers list onto the firing list. Per-thread timers
1060 * have already been taken off.
1062 static void check_process_timers(struct task_struct *tsk,
1063 struct list_head *firing)
1065 int maxfire;
1066 struct signal_struct *const sig = tsk->signal;
1067 cputime_t utime, ptime, virt_expires, prof_expires;
1068 unsigned long long sum_sched_runtime, sched_expires;
1069 struct list_head *timers = sig->cpu_timers;
1070 struct task_cputime cputime;
1071 unsigned long soft;
1074 * Collect the current process totals.
1076 thread_group_cputimer(tsk, &cputime);
1077 utime = cputime.utime;
1078 ptime = cputime_add(utime, cputime.stime);
1079 sum_sched_runtime = cputime.sum_exec_runtime;
1080 maxfire = 20;
1081 prof_expires = cputime_zero;
1082 while (!list_empty(timers)) {
1083 struct cpu_timer_list *tl = list_first_entry(timers,
1084 struct cpu_timer_list,
1085 entry);
1086 if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
1087 prof_expires = tl->expires.cpu;
1088 break;
1090 tl->firing = 1;
1091 list_move_tail(&tl->entry, firing);
1094 ++timers;
1095 maxfire = 20;
1096 virt_expires = cputime_zero;
1097 while (!list_empty(timers)) {
1098 struct cpu_timer_list *tl = list_first_entry(timers,
1099 struct cpu_timer_list,
1100 entry);
1101 if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
1102 virt_expires = tl->expires.cpu;
1103 break;
1105 tl->firing = 1;
1106 list_move_tail(&tl->entry, firing);
1109 ++timers;
1110 maxfire = 20;
1111 sched_expires = 0;
1112 while (!list_empty(timers)) {
1113 struct cpu_timer_list *tl = list_first_entry(timers,
1114 struct cpu_timer_list,
1115 entry);
1116 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1117 sched_expires = tl->expires.sched;
1118 break;
1120 tl->firing = 1;
1121 list_move_tail(&tl->entry, firing);
1125 * Check for the special case process timers.
1127 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
1128 SIGPROF);
1129 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
1130 SIGVTALRM);
1131 soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
1132 if (soft != RLIM_INFINITY) {
1133 unsigned long psecs = cputime_to_secs(ptime);
1134 unsigned long hard =
1135 ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
1136 cputime_t x;
1137 if (psecs >= hard) {
1139 * At the hard limit, we just die.
1140 * No need to calculate anything else now.
1142 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1143 return;
1145 if (psecs >= soft) {
1147 * At the soft limit, send a SIGXCPU every second.
1149 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1150 if (soft < hard) {
1151 soft++;
1152 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
1155 x = secs_to_cputime(soft);
1156 if (cputime_eq(prof_expires, cputime_zero) ||
1157 cputime_lt(x, prof_expires)) {
1158 prof_expires = x;
1162 sig->cputime_expires.prof_exp = prof_expires;
1163 sig->cputime_expires.virt_exp = virt_expires;
1164 sig->cputime_expires.sched_exp = sched_expires;
1165 if (task_cputime_zero(&sig->cputime_expires))
1166 stop_process_timers(sig);
1170 * This is called from the signal code (via do_schedule_next_timer)
1171 * when the last timer signal was delivered and we have to reload the timer.
1173 void posix_cpu_timer_schedule(struct k_itimer *timer)
1175 struct task_struct *p = timer->it.cpu.task;
1176 union cpu_time_count now;
1178 if (unlikely(p == NULL))
1180 * The task was cleaned up already, no future firings.
1182 goto out;
1185 * Fetch the current sample and update the timer's expiry time.
1187 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1188 cpu_clock_sample(timer->it_clock, p, &now);
1189 bump_cpu_timer(timer, now);
1190 if (unlikely(p->exit_state)) {
1191 clear_dead_task(timer, now);
1192 goto out;
1194 read_lock(&tasklist_lock); /* arm_timer needs it. */
1195 spin_lock(&p->sighand->siglock);
1196 } else {
1197 read_lock(&tasklist_lock);
1198 if (unlikely(p->sighand == NULL)) {
1200 * The process has been reaped.
1201 * We can't even collect a sample any more.
1203 put_task_struct(p);
1204 timer->it.cpu.task = p = NULL;
1205 timer->it.cpu.expires.sched = 0;
1206 goto out_unlock;
1207 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1209 * We've noticed that the thread is dead, but
1210 * not yet reaped. Take this opportunity to
1211 * drop our task ref.
1213 clear_dead_task(timer, now);
1214 goto out_unlock;
1216 spin_lock(&p->sighand->siglock);
1217 cpu_timer_sample_group(timer->it_clock, p, &now);
1218 bump_cpu_timer(timer, now);
1219 /* Leave the tasklist_lock locked for the call below. */
1223 * Now re-arm for the new expiry time.
1225 BUG_ON(!irqs_disabled());
1226 arm_timer(timer);
1227 spin_unlock(&p->sighand->siglock);
1229 out_unlock:
1230 read_unlock(&tasklist_lock);
1232 out:
1233 timer->it_overrun_last = timer->it_overrun;
1234 timer->it_overrun = -1;
1235 ++timer->it_requeue_pending;
1239 * task_cputime_expired - Compare two task_cputime entities.
1241 * @sample: The task_cputime structure to be checked for expiration.
1242 * @expires: Expiration times, against which @sample will be checked.
1244 * Checks @sample against @expires to see if any field of @sample has expired.
1245 * Returns true if any field of the former is greater than the corresponding
1246 * field of the latter if the latter field is set. Otherwise returns false.
1248 static inline int task_cputime_expired(const struct task_cputime *sample,
1249 const struct task_cputime *expires)
1251 if (!cputime_eq(expires->utime, cputime_zero) &&
1252 cputime_ge(sample->utime, expires->utime))
1253 return 1;
1254 if (!cputime_eq(expires->stime, cputime_zero) &&
1255 cputime_ge(cputime_add(sample->utime, sample->stime),
1256 expires->stime))
1257 return 1;
1258 if (expires->sum_exec_runtime != 0 &&
1259 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1260 return 1;
1261 return 0;
1265 * fastpath_timer_check - POSIX CPU timers fast path.
1267 * @tsk: The task (thread) being checked.
1269 * Check the task and thread group timers. If both are zero (there are no
1270 * timers set) return false. Otherwise snapshot the task and thread group
1271 * timers and compare them with the corresponding expiration times. Return
1272 * true if a timer has expired, else return false.
1274 static inline int fastpath_timer_check(struct task_struct *tsk)
1276 struct signal_struct *sig;
1278 if (!task_cputime_zero(&tsk->cputime_expires)) {
1279 struct task_cputime task_sample = {
1280 .utime = tsk->utime,
1281 .stime = tsk->stime,
1282 .sum_exec_runtime = tsk->se.sum_exec_runtime
1285 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1286 return 1;
1289 sig = tsk->signal;
1290 if (sig->cputimer.running) {
1291 struct task_cputime group_sample;
1293 spin_lock(&sig->cputimer.lock);
1294 group_sample = sig->cputimer.cputime;
1295 spin_unlock(&sig->cputimer.lock);
1297 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1298 return 1;
1301 return 0;
1305 * This is called from the timer interrupt handler. The irq handler has
1306 * already updated our counts. We need to check if any timers fire now.
1307 * Interrupts are disabled.
1309 void run_posix_cpu_timers(struct task_struct *tsk)
1311 LIST_HEAD(firing);
1312 struct k_itimer *timer, *next;
1313 unsigned long flags;
1315 BUG_ON(!irqs_disabled());
1318 * The fast path checks that there are no expired thread or thread
1319 * group timers. If that's so, just return.
1321 if (!fastpath_timer_check(tsk))
1322 return;
1324 if (!lock_task_sighand(tsk, &flags))
1325 return;
1327 * Here we take off tsk->signal->cpu_timers[N] and
1328 * tsk->cpu_timers[N] all the timers that are firing, and
1329 * put them on the firing list.
1331 check_thread_timers(tsk, &firing);
1333 * If there are any active process wide timers (POSIX 1.b, itimers,
1334 * RLIMIT_CPU) cputimer must be running.
1336 if (tsk->signal->cputimer.running)
1337 check_process_timers(tsk, &firing);
1340 * We must release these locks before taking any timer's lock.
1341 * There is a potential race with timer deletion here, as the
1342 * siglock now protects our private firing list. We have set
1343 * the firing flag in each timer, so that a deletion attempt
1344 * that gets the timer lock before we do will give it up and
1345 * spin until we've taken care of that timer below.
1347 unlock_task_sighand(tsk, &flags);
1350 * Now that all the timers on our list have the firing flag,
1351 * no one will touch their list entries but us. We'll take
1352 * each timer's lock before clearing its firing flag, so no
1353 * timer call will interfere.
1355 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1356 int cpu_firing;
1358 spin_lock(&timer->it_lock);
1359 list_del_init(&timer->it.cpu.entry);
1360 cpu_firing = timer->it.cpu.firing;
1361 timer->it.cpu.firing = 0;
1363 * The firing flag is -1 if we collided with a reset
1364 * of the timer, which already reported this
1365 * almost-firing as an overrun. So don't generate an event.
1367 if (likely(cpu_firing >= 0))
1368 cpu_timer_fire(timer);
1369 spin_unlock(&timer->it_lock);
1374 * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1375 * The tsk->sighand->siglock must be held by the caller.
1377 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1378 cputime_t *newval, cputime_t *oldval)
1380 union cpu_time_count now;
1382 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1383 cpu_timer_sample_group(clock_idx, tsk, &now);
1385 if (oldval) {
1387 * We are setting itimer. The *oldval is absolute and we update
1388 * it to be relative, *newval argument is relative and we update
1389 * it to be absolute.
1391 if (!cputime_eq(*oldval, cputime_zero)) {
1392 if (cputime_le(*oldval, now.cpu)) {
1393 /* Just about to fire. */
1394 *oldval = cputime_one_jiffy;
1395 } else {
1396 *oldval = cputime_sub(*oldval, now.cpu);
1400 if (cputime_eq(*newval, cputime_zero))
1401 return;
1402 *newval = cputime_add(*newval, now.cpu);
1406 * Update expiration cache if we are the earliest timer, or eventually
1407 * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1409 switch (clock_idx) {
1410 case CPUCLOCK_PROF:
1411 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1412 tsk->signal->cputime_expires.prof_exp = *newval;
1413 break;
1414 case CPUCLOCK_VIRT:
1415 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1416 tsk->signal->cputime_expires.virt_exp = *newval;
1417 break;
1421 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1422 struct timespec *rqtp, struct itimerspec *it)
1424 struct k_itimer timer;
1425 int error;
1428 * Set up a temporary timer and then wait for it to go off.
1430 memset(&timer, 0, sizeof timer);
1431 spin_lock_init(&timer.it_lock);
1432 timer.it_clock = which_clock;
1433 timer.it_overrun = -1;
1434 error = posix_cpu_timer_create(&timer);
1435 timer.it_process = current;
1436 if (!error) {
1437 static struct itimerspec zero_it;
1439 memset(it, 0, sizeof *it);
1440 it->it_value = *rqtp;
1442 spin_lock_irq(&timer.it_lock);
1443 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1444 if (error) {
1445 spin_unlock_irq(&timer.it_lock);
1446 return error;
1449 while (!signal_pending(current)) {
1450 if (timer.it.cpu.expires.sched == 0) {
1452 * Our timer fired and was reset.
1454 spin_unlock_irq(&timer.it_lock);
1455 return 0;
1459 * Block until cpu_timer_fire (or a signal) wakes us.
1461 __set_current_state(TASK_INTERRUPTIBLE);
1462 spin_unlock_irq(&timer.it_lock);
1463 schedule();
1464 spin_lock_irq(&timer.it_lock);
1468 * We were interrupted by a signal.
1470 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1471 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1472 spin_unlock_irq(&timer.it_lock);
1474 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1476 * It actually did fire already.
1478 return 0;
1481 error = -ERESTART_RESTARTBLOCK;
1484 return error;
1487 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1489 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1490 struct timespec *rqtp, struct timespec __user *rmtp)
1492 struct restart_block *restart_block =
1493 &current_thread_info()->restart_block;
1494 struct itimerspec it;
1495 int error;
1498 * Diagnose required errors first.
1500 if (CPUCLOCK_PERTHREAD(which_clock) &&
1501 (CPUCLOCK_PID(which_clock) == 0 ||
1502 CPUCLOCK_PID(which_clock) == current->pid))
1503 return -EINVAL;
1505 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1507 if (error == -ERESTART_RESTARTBLOCK) {
1509 if (flags & TIMER_ABSTIME)
1510 return -ERESTARTNOHAND;
1512 * Report back to the user the time still remaining.
1514 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1515 return -EFAULT;
1517 restart_block->fn = posix_cpu_nsleep_restart;
1518 restart_block->nanosleep.clockid = which_clock;
1519 restart_block->nanosleep.rmtp = rmtp;
1520 restart_block->nanosleep.expires = timespec_to_ns(rqtp);
1522 return error;
1525 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1527 clockid_t which_clock = restart_block->nanosleep.clockid;
1528 struct timespec t;
1529 struct itimerspec it;
1530 int error;
1532 t = ns_to_timespec(restart_block->nanosleep.expires);
1534 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1536 if (error == -ERESTART_RESTARTBLOCK) {
1537 struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
1539 * Report back to the user the time still remaining.
1541 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1542 return -EFAULT;
1544 restart_block->nanosleep.expires = timespec_to_ns(&t);
1546 return error;
1550 #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1551 #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1553 static int process_cpu_clock_getres(const clockid_t which_clock,
1554 struct timespec *tp)
1556 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1558 static int process_cpu_clock_get(const clockid_t which_clock,
1559 struct timespec *tp)
1561 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1563 static int process_cpu_timer_create(struct k_itimer *timer)
1565 timer->it_clock = PROCESS_CLOCK;
1566 return posix_cpu_timer_create(timer);
1568 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1569 struct timespec *rqtp,
1570 struct timespec __user *rmtp)
1572 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1574 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1576 return -EINVAL;
1578 static int thread_cpu_clock_getres(const clockid_t which_clock,
1579 struct timespec *tp)
1581 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1583 static int thread_cpu_clock_get(const clockid_t which_clock,
1584 struct timespec *tp)
1586 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1588 static int thread_cpu_timer_create(struct k_itimer *timer)
1590 timer->it_clock = THREAD_CLOCK;
1591 return posix_cpu_timer_create(timer);
1594 struct k_clock clock_posix_cpu = {
1595 .clock_getres = posix_cpu_clock_getres,
1596 .clock_set = posix_cpu_clock_set,
1597 .clock_get = posix_cpu_clock_get,
1598 .timer_create = posix_cpu_timer_create,
1599 .nsleep = posix_cpu_nsleep,
1600 .nsleep_restart = posix_cpu_nsleep_restart,
1601 .timer_set = posix_cpu_timer_set,
1602 .timer_del = posix_cpu_timer_del,
1603 .timer_get = posix_cpu_timer_get,
1606 static __init int init_posix_cpu_timers(void)
1608 struct k_clock process = {
1609 .clock_getres = process_cpu_clock_getres,
1610 .clock_get = process_cpu_clock_get,
1611 .timer_create = process_cpu_timer_create,
1612 .nsleep = process_cpu_nsleep,
1613 .nsleep_restart = process_cpu_nsleep_restart,
1615 struct k_clock thread = {
1616 .clock_getres = thread_cpu_clock_getres,
1617 .clock_get = thread_cpu_clock_get,
1618 .timer_create = thread_cpu_timer_create,
1620 struct timespec ts;
1622 posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1623 posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1625 cputime_to_timespec(cputime_one_jiffy, &ts);
1626 onecputick = ts.tv_nsec;
1627 WARN_ON(ts.tv_sec != 0);
1629 return 0;
1631 __initcall(init_posix_cpu_timers);