Release 4.7 kernel/time/posix-cpu-timers.c

/*
 * Implement CPU time clocks for the POSIX clock interface.
 */

#include <linux/sched.h>
#include <linux/posix-timers.h>
#include <linux/errno.h>
#include <linux/math64.h>
#include <asm/uaccess.h>
#include <linux/kernel_stat.h>
#include <trace/events/timer.h>
#include <linux/random.h>
#include <linux/tick.h>
#include <linux/workqueue.h>

/*
 * Called after updating RLIMIT_CPU to run cpu timer and update
 * tsk->signal->cputime_expires expiration cache if necessary. Needs
 * siglock protection since other code may update expiration cache as
 * well.
 */


void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
{
	cputime_t cputime = secs_to_cputime(rlim_new);

	spin_lock_irq(&task->sighand->siglock);
	set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
	spin_unlock_irq(&task->sighand->siglock);
}

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8
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stanislaw gruszka
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static int check_clock(const clockid_t which_clock)
{
	int error = 0;
	struct task_struct *p;
	const pid_t pid = CPUCLOCK_PID(which_clock);

	if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
		return -EINVAL;

	if (pid == 0)
		return 0;

	rcu_read_lock();
	p = find_task_by_vpid(pid);
	if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
		   same_thread_group(p, current) : has_group_leader_pid(p))) {
		error = -EINVAL;
	}
	rcu_read_unlock();

	return error;
}

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sergey senozhatsky
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static inline unsigned long long

timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
{
	unsigned long long ret;

	ret = 0;		/* high half always zero when .cpu used */
	if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
		ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
	} else {
		ret = cputime_to_expires(timespec_to_cputime(tp));
	}
	return ret;
}

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static void sample_to_timespec(const clockid_t which_clock,
			       unsigned long long expires,
			       struct timespec *tp)
{
	if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
		*tp = ns_to_timespec(expires);
	else
		cputime_to_timespec((__force cputime_t)expires, tp);
}

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roland mcgrath
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frederic weisbecker
frederic weisbecker
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roman zippel
roman zippel
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49
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4
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/*
 * Update expiry time from increment, and increase overrun count,
 * given the current clock sample.
 */


static void bump_cpu_timer(struct k_itimer *timer,
			   unsigned long long now)
{
	int i;
	unsigned long long delta, incr;

	if (timer->it.cpu.incr == 0)
		return;

	if (now < timer->it.cpu.expires)
		return;

	incr = timer->it.cpu.incr;
	delta = now + incr - timer->it.cpu.expires;

	/* Don't use (incr*2 < delta), incr*2 might overflow. */
	for (i = 0; incr < delta - incr; i++)
		incr = incr << 1;

	for (; i >= 0; incr >>= 1, i--) {
		if (delta < incr)
			continue;

		timer->it.cpu.expires += incr;
		timer->it_overrun += 1 << i;
		delta -= incr;
	}
}

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martin schwidefsky
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roland mcgrath
63
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frederic weisbecker
frederic weisbecker
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1
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143
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5
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/**
 * task_cputime_zero - Check a task_cputime struct for all zero fields.
 *
 * @cputime:    The struct to compare.
 *
 * Checks @cputime to see if all fields are zero.  Returns true if all fields
 * are zero, false if any field is nonzero.
 */


static inline int task_cputime_zero(const struct task_cputime *cputime)
{
	if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
		return 1;
	return 0;
}

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frederic weisbecker
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static inline unsigned long long prof_ticks(struct task_struct *p)
{
	cputime_t utime, stime;

	task_cputime(p, &utime, &stime);

	return cputime_to_expires(utime + stime);
}
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frederic weisbecker
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roland mcgrath
15
39.47%
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martin schwidefsky
martin schwidefsky
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static inline unsigned long long virt_ticks(struct task_struct *p)
{
	cputime_t utime;

	task_cputime(p, &utime, NULL);

	return cputime_to_expires(utime);
}

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frederic weisbecker
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static int

posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
{
	int error = check_clock(which_clock);
	if (!error) {
		tp->tv_sec = 0;
		tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
		if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
			/*
                         * If sched_clock is using a cycle counter, we
                         * don't have any idea of its true resolution
                         * exported, but it is much more than 1s/HZ.
                         */
			tp->tv_nsec = 1;
		}
	}
	return error;
}

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roland mcgrath
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thomas gleixner
thomas gleixner
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73
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static int

posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
{
	/*
         * You can never reset a CPU clock, but we check for other errors
         * in the call before failing with EPERM.
         */
	int error = check_clock(which_clock);
	if (error == 0) {
		error = -EPERM;
	}
	return error;
}


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roland mcgrath
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thomas gleixner
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/*
 * Sample a per-thread clock for the given task.
 */


static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
			    unsigned long long *sample)
{
	switch (CPUCLOCK_WHICH(which_clock)) {
	default:
		return -EINVAL;
	case CPUCLOCK_PROF:
		*sample = prof_ticks(p);
		break;
	case CPUCLOCK_VIRT:
		*sample = virt_ticks(p);
		break;
	case CPUCLOCK_SCHED:
		*sample = task_sched_runtime(p);
		break;
	}
	return 0;
}

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roland mcgrath
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frederic weisbecker
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hidetoshi seto
hidetoshi seto
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1
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thomas gleixner
thomas gleixner
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1
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74
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5
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/*
 * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
 * to avoid race conditions with concurrent updates to cputime.
 */


static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
{
	u64 curr_cputime;
retry:
	curr_cputime = atomic64_read(cputime);
	if (sum_cputime > curr_cputime) {
		if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
			goto retry;
	}
}

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static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
{
	__update_gt_cputime(&cputime_atomic->utime, sum->utime);
	__update_gt_cputime(&cputime_atomic->stime, sum->stime);
	__update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
}

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jason low
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peter zijlstra
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frederic weisbecker
frederic weisbecker
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/* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */


static inline void sample_cputime_atomic(struct task_cputime *times,
					 struct task_cputime_atomic *atomic_times)
{
	times->utime = atomic64_read(&atomic_times->utime);
	times->stime = atomic64_read(&atomic_times->stime);
	times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime);
}

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jason low
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peter zijlstra
peter zijlstra
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void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
{
	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
	struct task_cputime sum;

	/* Check if cputimer isn't running. This is accessed without locking. */
	if (!READ_ONCE(cputimer->running)) {
		/*
                 * The POSIX timer interface allows for absolute time expiry
                 * values through the TIMER_ABSTIME flag, therefore we have
                 * to synchronize the timer to the clock every time we start it.
                 */
		thread_group_cputime(tsk, &sum);
		update_gt_cputime(&cputimer->cputime_atomic, &sum);

		/*
                 * We're setting cputimer->running without a lock. Ensure
                 * this only gets written to in one operation. We set
                 * running after update_gt_cputime() as a small optimization,
                 * but barriers are not required because update_gt_cputime()
                 * can handle concurrent updates.
                 */
		WRITE_ONCE(cputimer->running, true);
	}
	sample_cputime_atomic(times, &cputimer->cputime_atomic);
}

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peter zijlstra
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jason low
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/*
 * Sample a process (thread group) clock for the given group_leader task.
 * Must be called with task sighand lock held for safe while_each_thread()
 * traversal.
 */


static int cpu_clock_sample_group(const clockid_t which_clock,
				  struct task_struct *p,
				  unsigned long long *sample)
{
	struct task_cputime cputime;

	switch (CPUCLOCK_WHICH(which_clock)) {
	default:
		return -EINVAL;
	case CPUCLOCK_PROF:
		thread_group_cputime(p, &cputime);
		*sample = cputime_to_expires(cputime.utime + cputime.stime);
		break;
	case CPUCLOCK_VIRT:
		thread_group_cputime(p, &cputime);
		*sample = cputime_to_expires(cputime.utime);
		break;
	case CPUCLOCK_SCHED:
		thread_group_cputime(p, &cputime);
		*sample = cputime.sum_exec_runtime;
		break;
	}
	return 0;
}

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roland mcgrath
roland mcgrath
35
32.11%
2
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frank mayhar
frank mayhar
26
23.85%
2
20.00%
hidetoshi seto
hidetoshi seto
16
14.68%
1
10.00%
frederic weisbecker
frederic weisbecker
16
14.68%
1
10.00%
peter zijlstra
peter zijlstra
11
10.09%
1
10.00%
petr tesarik
petr tesarik
3
2.75%
1
10.00%
martin schwidefsky
martin schwidefsky
1
0.92%
1
10.00%
ingo molnar
ingo molnar
1
0.92%
1
10.00%
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109
100.00%
10
100.00%



static int posix_cpu_clock_get_task(struct task_struct *tsk,
				    const clockid_t which_clock,
				    struct timespec *tp)
{
	int err = -EINVAL;
	unsigned long long rtn;

	if (CPUCLOCK_PERTHREAD(which_clock)) {
		if (same_thread_group(tsk, current))
			err = cpu_clock_sample(which_clock, tsk, &rtn);
	} else {
		if (tsk == current || thread_group_leader(tsk))
			err = cpu_clock_sample_group(which_clock, tsk, &rtn);
	}

	if (!err)
		sample_to_timespec(which_clock, rtn, tp);

	return err;
}


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frederic weisbecker
frederic weisbecker
45
43.27%
3
42.86%
frank mayhar
frank mayhar
31
29.81%
1
14.29%
roland mcgrath
roland mcgrath
25
24.04%
1
14.29%
pavel emelianov
pavel emelianov
2
1.92%
1
14.29%
thomas gleixner
thomas gleixner
1
0.96%
1
14.29%
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104
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7
100.00%



static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
{
	const pid_t pid = CPUCLOCK_PID(which_clock);
	int err = -EINVAL;

	if (pid == 0) {
		/*
                 * Special case constant value for our own clocks.
                 * We don't have to do any lookup to find ourselves.
                 */
		err = posix_cpu_clock_get_task(current, which_clock, tp);
	} else {
		/*
                 * Find the given PID, and validate that the caller
                 * should be able to see it.
                 */
		struct task_struct *p;
		rcu_read_lock();
		p = find_task_by_vpid(pid);
		if (p)
			err = posix_cpu_clock_get_task(p, which_clock, tp);
		rcu_read_unlock();
	}

	return err;
}

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frederic weisbecker
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linus torvalds
linus torvalds
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15.56%
1
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frank mayhar
frank mayhar
9
10.00%
1
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roland mcgrath
roland mcgrath
7
7.78%
1
20.00%
oleg nesterov
oleg nesterov
4
4.44%
1
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90
100.00%
5
100.00%

/*
 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
 * new timer already all-zeros initialized.
 */


static int posix_cpu_timer_create(struct k_itimer *new_timer)
{
	int ret = 0;
	const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
	struct task_struct *p;

	if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
		return -EINVAL;

	INIT_LIST_HEAD(&new_timer->it.cpu.entry);

	rcu_read_lock();
	if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
		if (pid == 0) {
			p = current;
		} else {
			p = find_task_by_vpid(pid);
			if (p && !same_thread_group(p, current))
				p = NULL;
		}
	} else {
		if (pid == 0) {
			p = current->group_leader;
		} else {
			p = find_task_by_vpid(pid);
			if (p && !has_group_leader_pid(p))
				p = NULL;
		}
	}
	new_timer->it.cpu.task = p;
	if (p) {
		get_task_struct(p);
	} else {
		ret = -EINVAL;
	}
	rcu_read_unlock();

	return ret;
}

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frank mayhar
frank mayhar
125
66.84%
1
25.00%
roland mcgrath
roland mcgrath
56
29.95%
1
25.00%
sergey senozhatsky
sergey senozhatsky
5
2.67%
1
25.00%
thomas gleixner
thomas gleixner
1
0.53%
1
25.00%
Total
187
100.00%
4
100.00%

/*
 * Clean up a CPU-clock timer that is about to be destroyed.
 * This is called from timer deletion with the timer already locked.
 * If we return TIMER_RETRY, it's necessary to release the timer's lock
 * and try again.  (This happens when the timer is in the middle of firing.)
 */


static int posix_cpu_timer_del(struct k_itimer *timer)
{
	int ret = 0;
	unsigned long flags;
	struct sighand_struct *sighand;
	struct task_struct *p = timer->it.cpu.task;

	WARN_ON_ONCE(p == NULL);

	/*
         * Protect against sighand release/switch in exit/exec and process/
         * thread timer list entry concurrent read/writes.
         */
	sighand = lock_task_sighand(p, &flags);
	if (unlikely(sighand == NULL)) {
		/*
                 * We raced with the reaping of the task.
                 * The deletion should have cleared us off the list.
                 */
		WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
	} else {
		if (timer->it.cpu.firing)
			ret = TIMER_RETRY;
		else
			list_del(&timer->it.cpu.entry);

		unlock_task_sighand(p, &flags);
	}

	if (!ret)
		put_task_struct(p);

	return ret;
}

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frank mayhar
frank mayhar
86
63.70%
1
12.50%
frederic weisbecker
frederic weisbecker
30
22.22%
3
37.50%
roland mcgrath
roland mcgrath
16
11.85%
1
12.50%
oleg nesterov
oleg nesterov
1
0.74%
1
12.50%
ingo molnar
ingo molnar
1
0.74%
1
12.50%
thomas gleixner
thomas gleixner
1
0.74%
1
12.50%
Total
135
100.00%
8
100.00%



static void cleanup_timers_list(struct list_head *head)
{
	struct cpu_timer_list *timer, *next;

	list_for_each_entry_safe(timer, next, head, entry)
		list_del_init(&timer->entry);
}

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frank mayhar
frank mayhar
19
51.35%
1
20.00%
roland mcgrath
roland mcgrath
14
37.84%
2
40.00%
frederic weisbecker
frederic weisbecker
2
5.41%
1
20.00%
martin schwidefsky
martin schwidefsky
2
5.41%
1
20.00%
Total
37
100.00%
5
100.00%

/*
 * Clean out CPU timers still ticking when a thread exited.  The task
 * pointer is cleared, and the expiry time is replaced with the residual
 * time for later timer_gettime calls to return.
 * This must be called with the siglock held.
 */


static void cleanup_timers(struct list_head *head)
{
	cleanup_timers_list(head);
	cleanup_timers_list(++head);
	cleanup_timers_list(++head);
}

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frederic weisbecker
frederic weisbecker
19
67.86%
2
50.00%
roland mcgrath
roland mcgrath
6
21.43%
1
25.00%
frank mayhar
frank mayhar
3
10.71%
1
25.00%
Total
28
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4
100.00%

/*
 * These are both called with the siglock held, when the current thread
 * is being reaped.  When the final (leader) thread in the group is reaped,
 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
 */


void posix_cpu_timers_exit(struct task_struct *tsk)
{
	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
						sizeof(unsigned long long));
	cleanup_timers(tsk->cpu_timers);

}
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nick kossifidis
nick kossifidis
22
56.41%
1
33.33%
frank mayhar
frank mayhar
13
33.33%
1
33.33%
roland mcgrath
roland mcgrath
4
10.26%
1
33.33%
Total
39
100.00%
3
100.00%



void posix_cpu_timers_exit_group(struct task_struct *tsk)
{
	cleanup_timers(tsk->signal->cpu_timers);
}

Contributors
Person
Tokens
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frank mayhar
frank mayhar
18
94.74%
1
50.00%
roland mcgrath
roland mcgrath
1
5.26%
1
50.00%
Total
19
100.00%
2
100.00%



static inline int expires_gt(cputime_t expires, cputime_t new_exp)
{
	return expires == 0 || expires > new_exp;
}

Contributors
Person
Tokens
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Commits
CommitProp
stanislaw gruszka
stanislaw gruszka
19
86.36%
1
50.00%
martin schwidefsky
martin schwidefsky
3
13.64%
1
50.00%
Total
22
100.00%
2
100.00%

/*
 * Insert the timer on the appropriate list before any timers that
 * expire later.  This must be called with the sighand lock held.
 */


static void arm_timer(struct k_itimer *timer)
{
	struct task_struct *p = timer->it.cpu.task;
	struct list_head *head, *listpos;
	struct task_cputime *cputime_expires;
	struct cpu_timer_list *const nt = &timer->it.cpu;
	struct cpu_timer_list *next;

	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
		head = p->cpu_timers;
		cputime_expires = &p->cputime_expires;
	} else {
		head = p->signal->cpu_timers;
		cputime_expires = &p->signal->cputime_expires;
	}
	head += CPUCLOCK_WHICH(timer->it_clock);

	listpos = head;
	list_for_each_entry(next, head, entry) {
		if (nt->expires < next->expires)
			break;
		listpos = &next->entry;
	}
	list_add(&nt->entry, listpos);

	if (listpos == head) {
		unsigned long long exp = nt->expires;

		/*
                 * We are the new earliest-expiring POSIX 1.b timer, hence
                 * need to update expiration cache. Take into account that
                 * for process timers we share expiration cache with itimers
                 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
                 */

		switch (CPUCLOCK_WHICH(timer->it_clock)) {
		case CPUCLOCK_PROF:
			if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
				cputime_expires->prof_exp = expires_to_cputime(exp);
			break;
		case CPUCLOCK_VIRT:
			if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
				cputime_expires->virt_exp = expires_to_cputime(exp);
			break;
		case CPUCLOCK_SCHED:
			if (cputime_expires->sched_exp == 0 ||
			    cputime_expires->sched_exp > exp)
				cputime_expires->sched_exp = exp;
			break;
		}
		if (CPUCLOCK_PERTHREAD(timer->it_clock))
			tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
		else
			tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
142
50.18%
2
20.00%
stanislaw gruszka
stanislaw gruszka
55
19.43%
3
30.00%
frederic weisbecker
frederic weisbecker
42
14.84%
2
20.00%
martin schwidefsky
martin schwidefsky
28
9.89%
1
10.00%
frank mayhar
frank mayhar
15
5.30%
1
10.00%
linus torvalds
linus torvalds
1
0.35%
1
10.00%
Total
283
100.00%
10
100.00%

/*
 * The timer is locked, fire it and arrange for its reload.
 */


static void cpu_timer_fire(struct k_itimer *timer)
{
	if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
		/*
                 * User don't want any signal.
                 */
		timer->it.cpu.expires = 0;
	} else if (unlikely(timer->sigq == NULL)) {
		/*
                 * This a special case for clock_nanosleep,
                 * not a normal timer from sys_timer_create.
                 */
		wake_up_process(timer->it_process);
		timer->it.cpu.expires = 0;
	} else if (timer->it.cpu.incr == 0) {
		/*
                 * One-shot timer.  Clear it as soon as it's fired.
                 */
		posix_timer_event(timer, 0);
		timer->it.cpu.expires = 0;
	} else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
		/*
                 * The signal did not get queued because the signal
                 * was ignored, so we won't get any callback to
                 * reload the timer.  But we need to keep it
                 * ticking in case the signal is deliverable next time.
                 */
		posix_cpu_timer_schedule(timer);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
96
78.05%
2
66.67%
stanislaw gruszka
stanislaw gruszka
27
21.95%
1
33.33%
Total
123
100.00%
3
100.00%

/*
 * Sample a process (thread group) timer for the given group_leader task.
 * Must be called with task sighand lock held for safe while_each_thread()
 * traversal.
 */


static int cpu_timer_sample_group(const clockid_t which_clock,
				  struct task_struct *p,
				  unsigned long long *sample)
{
	struct task_cputime cputime;

	thread_group_cputimer(p, &cputime);
	switch (CPUCLOCK_WHICH(which_clock)) {
	default:
		return -EINVAL;
	case CPUCLOCK_PROF:
		*sample = cputime_to_expires(cputime.utime + cputime.stime);
		break;
	case CPUCLOCK_VIRT:
		*sample = cputime_to_expires(cputime.utime);
		break;
	case CPUCLOCK_SCHED:
		*sample = cputime.sum_exec_runtime;
		break;
	}
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
peter zijlstra
peter zijlstra
76
81.72%
1
33.33%
frederic weisbecker
frederic weisbecker
16
17.20%
1
33.33%
martin schwidefsky
martin schwidefsky
1
1.08%
1
33.33%
Total
93
100.00%
3
100.00%

/*
 * Guts of sys_timer_settime for CPU timers.
 * This is called with the timer locked and interrupts disabled.
 * If we return TIMER_RETRY, it's necessary to release the timer's lock
 * and try again.  (This happens when the timer is in the middle of firing.)
 */


static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
			       struct itimerspec *new, struct itimerspec *old)
{
	unsigned long flags;
	struct sighand_struct *sighand;
	struct task_struct *p = timer->it.cpu.task;
	unsigned long long old_expires, new_expires, old_incr, val;
	int ret;

	WARN_ON_ONCE(p == NULL);

	new_expires = timespec_to_sample(timer->it_clock, &new->it_value);

	/*
         * Protect against sighand release/switch in exit/exec and p->cpu_timers
         * and p->signal->cpu_timers read/write in arm_timer()
         */
	sighand = lock_task_sighand(p, &flags);
	/*
         * If p has just been reaped, we can no
         * longer get any information about it at all.
         */
	if (unlikely(sighand == NULL)) {
		return -ESRCH;
	}

	/*
         * Disarm any old timer after extracting its expiry time.
         */
	WARN_ON_ONCE(!irqs_disabled());

	ret = 0;
	old_incr = timer->it.cpu.incr;
	old_expires = timer->it.cpu.expires;
	if (unlikely(timer->it.cpu.firing)) {
		timer->it.cpu.firing = -1;
		ret = TIMER_RETRY;
	} else
		list_del_init(&timer->it.cpu.entry);

	/*
         * We need to sample the current value to convert the new
         * value from to relative and absolute, and to convert the
         * old value from absolute to relative.  To set a process
         * timer, we need a sample to balance the thread expiry
         * times (in arm_timer).  With an absolute time, we must
         * check if it's already passed.  In short, we need a sample.
         */
	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
		cpu_clock_sample(timer->it_clock, p, &val);
	} else {
		cpu_timer_sample_group(timer->it_clock, p, &val);
	}

	if (old) {
		if (old_expires == 0) {
			old->it_value.tv_sec = 0;
			old->it_value.tv_nsec = 0;
		} else {
			/*
                         * Update the timer in case it has
                         * overrun already.  If it has,
                         * we'll report it as having overrun
                         * and with the next reloaded timer
                         * already ticking, though we are
                         * swallowing that pending
                         * notification here to install the
                         * new setting.
                         */
			bump_cpu_timer(timer, val);
			if (val < timer->it.cpu.expires) {
				old_expires = timer->it.cpu.expires - val;
				sample_to_timespec(timer->it_clock,
						   old_expires,
						   &old->it_value);
			} else {
				old->it_value.tv_nsec = 1;
				old->it_value.tv_sec = 0;
			}
		}
	}

	if (unlikely(ret)) {
		/*
                 * We are colliding with the timer actually firing.
                 * Punt after filling in the timer's old value, and
                 * disable this firing since we are already reporting
                 * it as an overrun (thanks to bump_cpu_timer above).
                 */
		unlock_task_sighand(p, &flags);
		goto out;
	}

	if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
		new_expires += val;
	}

	/*
         * Install the new expiry time (or zero).
         * For a timer with no notification action, we don't actually
         * arm the timer (we'll just fake it for timer_gettime).
         */
	timer->it.cpu.expires = new_expires;
	if (new_expires != 0 && val < new_expires) {
		arm_timer(timer);
	}

	unlock_task_sighand(p, &flags);
	/*
         * Install the new reload setting, and
         * set up the signal and overrun bookkeeping.
         */
	timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
						&new->it_interval);

	/*
         * This acts as a modification timestamp for the timer,
         * so any automatic reload attempt will punt on seeing
         * that we have reset the timer manually.
         */
	timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
		~REQUEUE_PENDING;
	timer->it_overrun_last = 0;
	timer->it_overrun = -1;

	if (new_expires != 0 && !(val < new_expires)) {
		/*
                 * The designated time already passed, so we notify
                 * immediately, even if the thread never runs to
                 * accumulate more time on this clock.
                 */
		cpu_timer_fire(timer);
	}

	ret = 0;
 out:
	if (old) {
		sample_to_timespec(timer->it_clock,
				   old_incr, &old->it_interval);
	}

	return ret;
}

Contributors
Person
Tokens
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Commits
CommitProp
roland mcgrath
roland mcgrath
404
81.12%
1
9.09%
frederic weisbecker
frederic weisbecker
38
7.63%
4
36.36%
oleg nesterov
oleg nesterov
37
7.43%
2
18.18%
stanislaw gruszka
stanislaw gruszka
17
3.41%
2
18.18%
peter zijlstra
peter zijlstra
1
0.20%
1
9.09%
thomas gleixner
thomas gleixner
1
0.20%
1
9.09%
Total
498
100.00%
11
100.00%



static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
{
	unsigned long long now;
	struct task_struct *p = timer->it.cpu.task;

	WARN_ON_ONCE(p == NULL);

	/*
         * Easy part: convert the reload time.
         */
	sample_to_timespec(timer->it_clock,
			   timer->it.cpu.incr, &itp->it_interval);

	if (timer->it.cpu.expires == 0) {	/* Timer not armed at all.  */
		itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
		return;
	}

	/*
         * Sample the clock to take the difference with the expiry time.
         */
	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
		cpu_clock_sample(timer->it_clock, p, &now);
	} else {
		struct sighand_struct *sighand;
		unsigned long flags;

		/*
                 * Protect against sighand release/switch in exit/exec and
                 * also make timer sampling safe if it ends up calling
                 * thread_group_cputime().
                 */
		sighand = lock_task_sighand(p, &flags);
		if (unlikely(sighand == NULL)) {
			/*
                         * The process has been reaped.
                         * We can't even collect a sample any more.
                         * Call the timer disarmed, nothing else to do.
                         */
			timer->it.cpu.expires = 0;
			sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
					   &itp->it_value);
			return;
		} else {
			cpu_timer_sample_group(timer->it_clock, p, &now);
			unlock_task_sighand(p, &flags);
		}
	}

	if (now < timer->it.cpu.expires) {
		sample_to_timespec(timer->it_clock,
				   timer->it.cpu.expires - now,
				   &itp->it_value);
	} else {
		/*
                 * The timer should have expired already, but the firing
                 * hasn't taken place yet.  Say it's just about to expire.
                 */
		itp->it_value.tv_nsec = 1;
		itp->it_value.tv_sec = 0;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
199
76.25%
1
11.11%
frederic weisbecker
frederic weisbecker
58
22.22%
4
44.44%
alexey dobriyan
alexey dobriyan
1
0.38%
1
11.11%
thomas gleixner
thomas gleixner
1
0.38%
1
11.11%
oleg nesterov
oleg nesterov
1
0.38%
1
11.11%
peter zijlstra
peter zijlstra
1
0.38%
1
11.11%
Total
261
100.00%
9
100.00%


static unsigned long long

check_timers_list(struct list_head *timers,
		  struct list_head *firing,
		  unsigned long long curr)
{
	int maxfire = 20;

	while (!list_empty(timers)) {
		struct cpu_timer_list *t;

		t = list_first_entry(timers, struct cpu_timer_list, entry);

		if (!--maxfire || curr < t->expires)
			return t->expires;

		t->firing = 1;
		list_move_tail(&t->entry, firing);
	}

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
59
64.84%
1
20.00%
frederic weisbecker
frederic weisbecker
23
25.27%
1
20.00%
linus torvalds
linus torvalds
7
7.69%
1
20.00%
martin schwidefsky
martin schwidefsky
1
1.10%
1
20.00%
pavel emelianov
pavel emelianov
1
1.10%
1
20.00%
Total
91
100.00%
5
100.00%

/*
 * Check for any per-thread CPU timers that have fired and move them off
 * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
 */


static void check_thread_timers(struct task_struct *tsk,
				struct list_head *firing)
{
	struct list_head *timers = tsk->cpu_timers;
	struct signal_struct *const sig = tsk->signal;
	struct task_cputime *tsk_expires = &tsk->cputime_expires;
	unsigned long long expires;
	unsigned long soft;

	/*
         * If cputime_expires is zero, then there are no active
         * per thread CPU timers.
         */
	if (task_cputime_zero(&tsk->cputime_expires))
		return;

	expires = check_timers_list(timers, firing, prof_ticks(tsk));
	tsk_expires->prof_exp = expires_to_cputime(expires);

	expires = check_timers_list(++timers, firing, virt_ticks(tsk));
	tsk_expires->virt_exp = expires_to_cputime(expires);

	tsk_expires->sched_exp = check_timers_list(++timers, firing,
						   tsk->se.sum_exec_runtime);

	/*
         * Check for the special case thread timers.
         */
	soft = READ_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
	if (soft != RLIM_INFINITY) {
		unsigned long hard =
			READ_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);

		if (hard != RLIM_INFINITY &&
		    tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
			/*
                         * At the hard limit, we just die.
                         * No need to calculate anything else now.
                         */
			__group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
			return;
		}
		if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
			/*
                         * At the soft limit, send a SIGXCPU every second.
                         */
			if (soft < hard) {
				soft += USEC_PER_SEC;
				sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
			}
			printk(KERN_INFO
				"RT Watchdog Timeout: %s[%d]\n",
				tsk->comm, task_pid_nr(tsk));
			__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
		}
	}
	if (task_cputime_zero(tsk_expires))
		tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
peter zijlstra
peter zijlstra
105
36.84%
2
14.29%
frederic weisbecker
frederic weisbecker
93
32.63%
3
21.43%
roland mcgrath
roland mcgrath
34
11.93%
1
7.14%
jiri slaby
jiri slaby
18
6.32%
2
14.29%
hiroshi shimamoto
hiroshi shimamoto
15
5.26%
1
7.14%
jason low
jason low
14
4.91%
2
14.29%
ingo molnar
ingo molnar
3
1.05%
1
7.14%
linus torvalds
linus torvalds
2
0.70%
1
7.14%
frank mayhar
frank mayhar
1
0.35%
1
7.14%
Total
285
100.00%
14
100.00%



static inline void stop_process_timers(struct signal_struct *sig)
{
	struct thread_group_cputimer *cputimer = &sig->cputimer;

	/* Turn off cputimer->running. This is done without locking. */
	WRITE_ONCE(cputimer->running, false);
	tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
peter zijlstra
peter zijlstra
25
64.10%
1
20.00%
frederic weisbecker
frederic weisbecker
7
17.95%
1
20.00%
jason low
jason low
4
10.26%
2
40.00%
stanislaw gruszka
stanislaw gruszka
3
7.69%
1
20.00%
Total
39
100.00%
5
100.00%


static u32 onecputick;



static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
			     unsigned long long *expires,
			     unsigned long long cur_time, int signo)
{
	if (!it->expires)
		return;

	if (cur_time >= it->expires) {
		if (it->incr) {
			it->expires += it->incr;
			it->error += it->incr_error;
			if (it->error >= onecputick) {
				it->expires -= cputime_one_jiffy;
				it->error -= onecputick;
			}
		} else {
			it->expires = 0;
		}

		trace_itimer_expire(signo == SIGPROF ?
				    ITIMER_PROF : ITIMER_VIRTUAL,
				    tsk->signal->leader_pid, cur_time);
		__group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
	}

	if (it->expires && (!*expires || it->expires < *expires)) {
		*expires = it->expires;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
stanislaw gruszka
stanislaw gruszka
125
78.62%
3
50.00%
xiao guangrong
xiao guangrong
21
13.21%
1
16.67%
martin schwidefsky
martin schwidefsky
7
4.40%
1
16.67%
frederic weisbecker
frederic weisbecker
6
3.77%
1
16.67%
Total
159
100.00%
6
100.00%

/*
 * Check for any per-thread CPU timers that have fired and move them
 * off the tsk->*_timers list onto the firing list.  Per-thread timers
 * have already been taken off.
 */


static void check_process_timers(struct task_struct *tsk,
				 struct list_head *firing)
{
	struct signal_struct *const sig = tsk->signal;
	unsigned long long utime, ptime, virt_expires, prof_expires;
	unsigned long long sum_sched_runtime, sched_expires;
	struct list_head *timers = sig->cpu_timers;
	struct task_cputime cputime;
	unsigned long soft;

	/*
         * If cputimer is not running, then there are no active
         * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
         */
	if (!READ_ONCE(tsk->signal->cputimer.running))
		return;

        /*
         * Signify that a thread is checking for process timers.
         * Write access to this field is protected by the sighand lock.
         */
	sig->cputimer.checking_timer = true;

	/*
         * Collect the current process totals.
         */
	thread_group_cputimer(tsk, &cputime);
	utime = cputime_to_expires(cputime.utime);
	ptime = utime + cputime_to_expires(cputime.stime);
	sum_sched_runtime = cputime.sum_exec_runtime;

	prof_expires = check_timers_list(timers, firing, ptime);
	virt_expires = check_timers_list(++timers, firing, utime);
	sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);

	/*
         * Check for the special case process timers.
         */
	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
			 SIGPROF);
	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
			 SIGVTALRM);
	soft = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
	if (soft != RLIM_INFINITY) {
		unsigned long psecs = cputime_to_secs(ptime);
		unsigned long hard =
			READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
		cputime_t x;
		if (psecs >= hard) {
			/*
                         * At the hard limit, we just die.
                         * No need to calculate anything else now.
                         */
			__group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
			return;
		}
		if (psecs >= soft) {
			/*
                         * At the soft limit, send a SIGXCPU every second.
                         */
			__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
			if (soft < hard) {
				soft++;
				sig->rlim[RLIMIT_CPU].rlim_cur = soft;
			}
		}
		x = secs_to_cputime(soft);
		if (!prof_expires || x < prof_expires) {
			prof_expires = x;
		}
	}

	sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
	sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
	sig->cputime_expires.sched_exp = sched_expires;
	if (task_cputime_zero(&sig->cputime_expires))
		stop_process_timers(sig);

	sig->cputimer.checking_timer = false;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
206
54.07%
3
17.65%
frank mayhar
frank mayhar
41
10.76%
1
5.88%
jiri slaby
jiri slaby
36
9.45%
2
11.76%
jason low
jason low
35
9.19%
3
17.65%
stanislaw gruszka
stanislaw gruszka
30
7.87%
2
11.76%
frederic weisbecker
frederic weisbecker
23
6.04%
2
11.76%
ingo molnar
ingo molnar
5
1.31%
1
5.88%
martin schwidefsky
martin schwidefsky
4
1.05%
2
11.76%
peter zijlstra
peter zijlstra
1
0.26%
1
5.88%
Total
381
100.00%
17
100.00%

/*
 * This is called from the signal code (via do_schedule_next_timer)
 * when the last timer signal was delivered and we have to reload the timer.
 */


void posix_cpu_timer_schedule(struct k_itimer *timer)
{
	struct sighand_struct *sighand;
	unsigned long flags;
	struct task_struct *p = timer->it.cpu.task;
	unsigned long long now;

	WARN_ON_ONCE(p == NULL);

	/*
         * Fetch the current sample and update the timer's expiry time.
         */
	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
		cpu_clock_sample(timer->it_clock, p, &now);
		bump_cpu_timer(timer, now);
		if (unlikely(p->exit_state))
			goto out;

		/* Protect timer list r/w in arm_timer() */
		sighand = lock_task_sighand(p, &flags);
		if (!sighand)
			goto out;
	} else {
		/*
                 * Protect arm_timer() and timer sampling in case of call to
                 * thread_group_cputime().
                 */
		sighand = lock_task_sighand(p, &flags);
		if (unlikely(sighand == NULL)) {
			/*
                         * The process has been reaped.
                         * We can't even collect a sample any more.
                         */
			timer->it.cpu.expires = 0;
			goto out;
		} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
			unlock_task_sighand(p, &flags);
			/* Optimizations: if the process is dying, no need to rearm */
			goto out;
		}
		cpu_timer_sample_group(timer->it_clock, p, &now);
		bump_cpu_timer(timer, now);
		/* Leave the sighand locked for the call below.  */
	}

	/*
         * Now re-arm for the new expiry time.
         */
	WARN_ON_ONCE(!irqs_disabled());
	arm_timer(timer);
	unlock_task_sighand(p, &flags);

out:
	timer->it_overrun_last = timer->it_overrun;
	timer->it_overrun = -1;
	++timer->it_requeue_pending;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
frank mayhar
frank mayhar
118
49.79%
1
8.33%
roland mcgrath
roland mcgrath
57
24.05%
1
8.33%
frederic weisbecker
frederic weisbecker
51
21.52%
7
58.33%
stanislaw gruszka
stanislaw gruszka
9
3.80%
1
8.33%
peter zijlstra
peter zijlstra
1
0.42%
1
8.33%
oleg nesterov
oleg nesterov
1
0.42%
1
8.33%
Total
237
100.00%
12
100.00%

/**
 * task_cputime_expired - Compare two task_cputime entities.
 *
 * @sample:     The task_cputime structure to be checked for expiration.
 * @expires:    Expiration times, against which @sample will be checked.
 *
 * Checks @sample against @expires to see if any field of @sample has expired.
 * Returns true if any field of the former is greater than the corresponding
 * field of the latter if the latter field is set.  Otherwise returns false.
 */


static inline int task_cputime_expired(const struct task_cputime *sample,
					const struct task_cputime *expires)
{
	if (expires->utime && sample->utime >= expires->utime)
		return 1;
	if (expires->stime && sample->utime + sample->stime >= expires->stime)
		return 1;
	if (expires->sum_exec_runtime != 0 &&
	    sample->sum_exec_runtime >= expires->sum_exec_runtime)
		return 1;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
frank mayhar
frank mayhar
71
89.87%
1
33.33%
roland mcgrath
roland mcgrath
5
6.33%
1
33.33%
martin schwidefsky
martin schwidefsky
3
3.80%
1
33.33%
Total
79
100.00%
3
100.00%

/**
 * fastpath_timer_check - POSIX CPU timers fast path.
 *
 * @tsk:        The task (thread) being checked.
 *
 * Check the task and thread group timers.  If both are zero (there are no
 * timers set) return false.  Otherwise snapshot the task and thread group
 * timers and compare them with the corresponding expiration times.  Return
 * true if a timer has expired, else return false.
 */


static inline int fastpath_timer_check(struct task_struct *tsk)
{
	struct signal_struct *sig;

	if (!task_cputime_zero(&tsk->cputime_expires)) {
		struct task_cputime task_sample;

		task_cputime(tsk, &task_sample.utime, &task_sample.stime);
		task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
		if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
			return 1;
	}

	sig = tsk->signal;
	/*
         * Check if thread group timers expired when the cputimer is
         * running and no other thread in the group is already checking
         * for thread group cputimers. These fields are read without the
         * sighand lock. However, this is fine because this is meant to
         * be a fastpath heuristic to determine whether we should try to
         * acquire the sighand lock to check/handle timers.
         *
         * In the worst case scenario, if 'running' or 'checking_timer' gets
         * set but the current thread doesn't see the change yet, we'll wait
         * until the next thread in the group gets a scheduler interrupt to
         * handle the timer. This isn't an issue in practice because these
         * types of delays with signals actually getting sent are expected.
         */
	if (READ_ONCE(sig->cputimer.running) &&
	    !READ_ONCE(sig->cputimer.checking_timer)) {
		struct task_cputime group_sample;

		sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);

		if (task_cputime_expired(&group_sample, &sig->cputime_expires))
			return 1;
	}

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
frank mayhar
frank mayhar
78
55.32%
2
15.38%
jason low
jason low
32
22.70%
4
30.77%
roland mcgrath
roland mcgrath
17
12.06%
3
23.08%
oleg nesterov
oleg nesterov
10
7.09%
2
15.38%
stanislaw gruszka
stanislaw gruszka
4
2.84%
2
15.38%
Total
141
100.00%
13
100.00%

/*
 * This is called from the timer interrupt handler.  The irq handler has
 * already updated our counts.  We need to check if any timers fire now.
 * Interrupts are disabled.
 */


void run_posix_cpu_timers(struct task_struct *tsk)
{
	LIST_HEAD(firing);
	struct k_itimer *timer, *next;
	unsigned long flags;

	WARN_ON_ONCE(!irqs_disabled());

	/*
         * The fast path checks that there are no expired thread or thread
         * group timers.  If that's so, just return.
         */
	if (!fastpath_timer_check(tsk))
		return;

	if (!lock_task_sighand(tsk, &flags))
		return;
	/*
         * Here we take off tsk->signal->cpu_timers[N] and
         * tsk->cpu_timers[N] all the timers that are firing, and
         * put them on the firing list.
         */
	check_thread_timers(tsk, &firing);

	check_process_timers(tsk, &firing);

	/*
         * We must release these locks before taking any timer's lock.
         * There is a potential race with timer deletion here, as the
         * siglock now protects our private firing list.  We have set
         * the firing flag in each timer, so that a deletion attempt
         * that gets the timer lock before we do will give it up and
         * spin until we've taken care of that timer below.
         */
	unlock_task_sighand(tsk, &flags);

	/*
         * Now that all the timers on our list have the firing flag,
         * no one will touch their list entries but us.  We'll take
         * each timer's lock before clearing its firing flag, so no
         * timer call will interfere.
         */
	list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
		int cpu_firing;

		spin_lock(&timer->it_lock);
		list_del_init(&timer->it.cpu.entry);
		cpu_firing = timer->it.cpu.firing;
		timer->it.cpu.firing = 0;
		/*
                 * The firing flag is -1 if we collided with a reset
                 * of the timer, which already reported this
                 * almost-firing as an overrun.  So don't generate an event.
                 */
		if (likely(cpu_firing >= 0))
			cpu_timer_fire(timer);
		spin_unlock(&timer->it_lock);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
129
80.12%
2
22.22%
oleg nesterov
oleg nesterov
18
11.18%
2
22.22%
frank mayhar
frank mayhar
9
5.59%
2
22.22%
h hartley sweeten
h hartley sweeten
3
1.86%
1
11.11%
lucas de marchi
lucas de marchi
1
0.62%
1
11.11%
frederic weisbecker
frederic weisbecker
1
0.62%
1
11.11%
Total
161
100.00%
9
100.00%

/*
 * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
 * The tsk->sighand->siglock must be held by the caller.
 */


void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
			   cputime_t *newval, cputime_t *oldval)
{
	unsigned long long now;

	WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
	cpu_timer_sample_group(clock_idx, tsk, &now);

	if (oldval) {
		/*
                 * We are setting itimer. The *oldval is absolute and we update
                 * it to be relative, *newval argument is relative and we update
                 * it to be absolute.
                 */
		if (*oldval) {
			if (*oldval <= now) {
				/* Just about to fire. */
				*oldval = cputime_one_jiffy;
			} else {
				*oldval -= now;
			}
		}

		if (!*newval)
			return;
		*newval += now;
	}

	/*
         * Update expiration cache if we are the earliest timer, or eventually
         * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
         */
	switch (clock_idx) {
	case CPUCLOCK_PROF:
		if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
			tsk->signal->cputime_expires.prof_exp = *newval;
		break;
	case CPUCLOCK_VIRT:
		if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
			tsk->signal->cputime_expires.virt_exp = *newval;
		break;
	}

	tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
100
58.48%
2
18.18%
stanislaw gruszka
stanislaw gruszka
31
18.13%
2
18.18%
frank mayhar
frank mayhar
21
12.28%
1
9.09%
frederic weisbecker
frederic weisbecker
14
8.19%
4
36.36%
martin schwidefsky
martin schwidefsky
4
2.34%
1
9.09%
peter zijlstra
peter zijlstra
1
0.58%
1
9.09%
Total
171
100.00%
11
100.00%



static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
			    struct timespec *rqtp, struct itimerspec *it)
{
	struct k_itimer timer;
	int error;

	/*
         * Set up a temporary timer and then wait for it to go off.
         */
	memset(&timer, 0, sizeof timer);
	spin_lock_init(&timer.it_lock);
	timer.it_clock = which_clock;
	timer.it_overrun = -1;
	error = posix_cpu_timer_create(&timer);
	timer.it_process = current;
	if (!error) {
		static struct itimerspec zero_it;

		memset(it, 0, sizeof *it);
		it->it_value = *rqtp;

		spin_lock_irq(&timer.it_lock);
		error = posix_cpu_timer_set(&timer, flags, it, NULL);
		if (error) {
			spin_unlock_irq(&timer.it_lock);
			return error;
		}

		while (!signal_pending(current)) {
			if (timer.it.cpu.expires == 0) {
				/*
                                 * Our timer fired and was reset, below
                                 * deletion can not fail.
                                 */
				posix_cpu_timer_del(&timer);
				spin_unlock_irq(&timer.it_lock);
				return 0;
			}

			/*
                         * Block until cpu_timer_fire (or a signal) wakes us.
                         */
			__set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(&timer.it_lock);
			schedule();
			spin_lock_irq(&timer.it_lock);
		}

		/*
                 * We were interrupted by a signal.
                 */
		sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
		error = posix_cpu_timer_set(&timer, 0, &zero_it, it);
		if (!error) {
			/*
                         * Timer is now unarmed, deletion can not fail.
                         */
			posix_cpu_timer_del(&timer);
		}
		spin_unlock_irq(&timer.it_lock);

		while (error == TIMER_RETRY) {
			/*
                         * We need to handle case when timer was or is in the
                         * middle of firing. In other cases we already freed
                         * resources.
                         */
			spin_lock_irq(&timer.it_lock);
			error = posix_cpu_timer_del(&timer);
			spin_unlock_irq(&timer.it_lock);
		}

		if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
			/*
                         * It actually did fire already.
                         */
			return 0;
		}

		error = -ERESTART_RESTARTBLOCK;
	}

	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
242
73.11%
2
33.33%
stanislaw gruszka
stanislaw gruszka
56
16.92%
1
16.67%
toyo abe
toyo abe
29
8.76%
1
16.67%
thomas gleixner
thomas gleixner
4
1.21%
2
33.33%
Total
331
100.00%
6
100.00%

static long posix_cpu_nsleep_restart(struct restart_block *restart_block);



static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
			    struct timespec *rqtp, struct timespec __user *rmtp)
{
	struct restart_block *restart_block = &current->restart_block;
	struct itimerspec it;
	int error;

	/*
         * Diagnose required errors first.
         */
	if (CPUCLOCK_PERTHREAD(which_clock) &&
	    (CPUCLOCK_PID(which_clock) == 0 ||
	     CPUCLOCK_PID(which_clock) == current->pid))
		return -EINVAL;

	error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);

	if (error == -ERESTART_RESTARTBLOCK) {

		if (flags & TIMER_ABSTIME)
			return -ERESTARTNOHAND;
		/*
                 * Report back to the user the time still remaining.
                 */
		if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
			return -EFAULT;

		restart_block->fn = posix_cpu_nsleep_restart;
		restart_block->nanosleep.clockid = which_clock;
		restart_block->nanosleep.rmtp = rmtp;
		restart_block->nanosleep.expires = timespec_to_ns(rqtp);
	}
	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
toyo abe
toyo abe
97
59.51%
2
22.22%
roland mcgrath
roland mcgrath
50
30.67%
2
22.22%
thomas gleixner
thomas gleixner
15
9.20%
4
44.44%
andy lutomirski
andy lutomirski
1
0.61%
1
11.11%
Total
163
100.00%
9
100.00%



static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
{
	clockid_t which_clock = restart_block->nanosleep.clockid;
	struct timespec t;
	struct itimerspec it;
	int error;

	t = ns_to_timespec(restart_block->nanosleep.expires);

	error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);

	if (error == -ERESTART_RESTARTBLOCK) {
		struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
		/*
                 * Report back to the user the time still remaining.
                 */
		if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
			return -EFAULT;

		restart_block->nanosleep.expires = timespec_to_ns(&t);
	}
	return error;

}

Contributors
Person
Tokens
Prop
Commits
CommitProp
toyo abe
toyo abe
52
44.83%
2
25.00%
thomas gleixner
thomas gleixner
35
30.17%
4
50.00%
roland mcgrath
roland mcgrath
29
25.00%
2
25.00%
Total
116
100.00%
8
100.00%


#define PROCESS_CLOCK	MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)

#define THREAD_CLOCK	MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)



static int process_cpu_clock_getres(const clockid_t which_clock,
				    struct timespec *tp)
{
	return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
22
95.65%
1
50.00%
thomas gleixner
thomas gleixner
1
4.35%
1
50.00%
Total
23
100.00%
2
100.00%



static int process_cpu_clock_get(const clockid_t which_clock,
				 struct timespec *tp)
{
	return posix_cpu_clock_get(PROCESS_CLOCK, tp);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
22
95.65%
1
50.00%
thomas gleixner
thomas gleixner
1
4.35%
1
50.00%
Total
23
100.00%
2
100.00%



static int process_cpu_timer_create(struct k_itimer *timer)
{
	timer->it_clock = PROCESS_CLOCK;
	return posix_cpu_timer_create(timer);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
23
100.00%
1
100.00%
Total
23
100.00%
1
100.00%



static int process_cpu_nsleep(const clockid_t which_clock, int flags,
			      struct timespec *rqtp,
			      struct timespec __user *rmtp)
{
	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
27
75.00%
1
33.33%
thomas gleixner
thomas gleixner
9
25.00%
2
66.67%
Total
36
100.00%
3
100.00%



static long process_cpu_nsleep_restart(struct restart_block *restart_block)
{
	return -EINVAL;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
toyo abe
toyo abe
15
100.00%
1
100.00%
Total
15
100.00%
1
100.00%



static int thread_cpu_clock_getres(const clockid_t which_clock,
				   struct timespec *tp)
{
	return posix_cpu_clock_getres(THREAD_CLOCK, tp);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
22
95.65%
1
50.00%
thomas gleixner
thomas gleixner
1
4.35%
1
50.00%
Total
23
100.00%
2
100.00%



static int thread_cpu_clock_get(const clockid_t which_clock,
				struct timespec *tp)
{
	return posix_cpu_clock_get(THREAD_CLOCK, tp);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
22
95.65%
1
50.00%
thomas gleixner
thomas gleixner
1
4.35%
1
50.00%
Total
23
100.00%
2
100.00%



static int thread_cpu_timer_create(struct k_itimer *timer)
{
	timer->it_clock = THREAD_CLOCK;
	return posix_cpu_timer_create(timer);
}

Contributors
Person
Tokens
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CommitProp
roland mcgrath
roland mcgrath
23
100.00%
1
100.00%
Total
23
100.00%
1
100.00%


struct k_clock clock_posix_cpu = {
	.clock_getres	= posix_cpu_clock_getres,
	.clock_set	= posix_cpu_clock_set,
	.clock_get	= posix_cpu_clock_get,
	.timer_create	= posix_cpu_timer_create,
	.nsleep		= posix_cpu_nsleep,
	.nsleep_restart	= posix_cpu_nsleep_restart,
	.timer_set	= posix_cpu_timer_set,
	.timer_del	= posix_cpu_timer_del,
	.timer_get	= posix_cpu_timer_get,
};



static __init int init_posix_cpu_timers(void)
{
	struct k_clock process = {
		.clock_getres	= process_cpu_clock_getres,
		.clock_get	= process_cpu_clock_get,
		.timer_create	= process_cpu_timer_create,
		.nsleep		= process_cpu_nsleep,
		.nsleep_restart	= process_cpu_nsleep_restart,
        };
	struct k_clock thread = {
		.clock_getres	= thread_cpu_clock_getres,
		.clock_get	= thread_cpu_clock_get,
		.timer_create	= thread_cpu_timer_create,
        };
	struct timespec ts;

	posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
	posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);

	cputime_to_timespec(cputime_one_jiffy, &ts);
	onecputick = ts.tv_nsec;
	WARN_ON(ts.tv_sec != 0);

	return 0;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
73
68.22%
2
33.33%
stanislaw gruszka
stanislaw gruszka
27
25.23%
2
33.33%
toyo abe
toyo abe
5
4.67%
1
16.67%
thomas gleixner
thomas gleixner
2
1.87%
1
16.67%
Total
107
100.00%
6
100.00%


__initcall(init_posix_cpu_timers);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
roland mcgrath
roland mcgrath
2474
42.94%
6
6.59%
frank mayhar
frank mayhar
919
15.95%
2
2.20%
frederic weisbecker
frederic weisbecker
668
11.60%
17
18.68%
stanislaw gruszka
stanislaw gruszka
412
7.15%
13
14.29%
peter zijlstra
peter zijlstra
321
5.57%
8
8.79%
jason low
jason low
226
3.92%
7
7.69%
toyo abe
toyo abe
198
3.44%
2
2.20%
thomas gleixner
thomas gleixner
140
2.43%
7
7.69%
martin schwidefsky
martin schwidefsky
126
2.19%
2
2.20%
oleg nesterov
oleg nesterov
72
1.25%
7
7.69%
jiri slaby
jiri slaby
62
1.08%
3
3.30%
nick kossifidis
nick kossifidis
25
0.43%
1
1.10%
xiao guangrong
xiao guangrong
24
0.42%
1
1.10%
linus torvalds
linus torvalds
24
0.42%
3
3.30%
hidetoshi seto
hidetoshi seto
17
0.30%
1
1.10%
hiroshi shimamoto
hiroshi shimamoto
15
0.26%
1
1.10%
ingo molnar
ingo molnar
10
0.17%
1
1.10%
sergey senozhatsky
sergey senozhatsky
10
0.17%
1
1.10%
roman zippel
roman zippel
6
0.10%
1
1.10%
pavel emelianov
pavel emelianov
3
0.05%
2
2.20%
petr tesarik
petr tesarik
3
0.05%
1
1.10%
h hartley sweeten
h hartley sweeten
3
0.05%
1
1.10%
lucas de marchi
lucas de marchi
1
0.02%
1
1.10%
alexey dobriyan
alexey dobriyan
1
0.02%
1
1.10%
andy lutomirski
andy lutomirski
1
0.02%
1
1.10%
Total
5761
100.00%
91
100.00%
  
Directory: kernel/time

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