Release 4.15 kernel/time/hrtimer.c

/*
 *  linux/kernel/hrtimer.c
 *
 *  Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
 *  Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
 *  Copyright(C) 2006-2007  Timesys Corp., Thomas Gleixner
 *
 *  High-resolution kernel timers
 *
 *  In contrast to the low-resolution timeout API implemented in
 *  kernel/timer.c, hrtimers provide finer resolution and accuracy
 *  depending on system configuration and capabilities.
 *
 *  These timers are currently used for:
 *   - itimers
 *   - POSIX timers
 *   - nanosleep
 *   - precise in-kernel timing
 *
 *  Started by: Thomas Gleixner and Ingo Molnar
 *
 *  Credits:
 *      based on kernel/timer.c
 *
 *      Help, testing, suggestions, bugfixes, improvements were
 *      provided by:
 *
 *      George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
 *      et. al.
 *
 *  For licencing details see kernel-base/COPYING
 */

#include <linux/cpu.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/hrtimer.h>
#include <linux/notifier.h>
#include <linux/syscalls.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/tick.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/debugobjects.h>
#include <linux/sched/signal.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/rt.h>
#include <linux/sched/deadline.h>
#include <linux/sched/nohz.h>
#include <linux/sched/debug.h>
#include <linux/timer.h>
#include <linux/freezer.h>
#include <linux/compat.h>

#include <linux/uaccess.h>

#include <trace/events/timer.h>

#include "tick-internal.h"

/*
 * The timer bases:
 *
 * There are more clockids than hrtimer bases. Thus, we index
 * into the timer bases by the hrtimer_base_type enum. When trying
 * to reach a base using a clockid, hrtimer_clockid_to_base()
 * is used to convert from clockid to the proper hrtimer_base_type.
 */
DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
{
	.lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
	.seq = SEQCNT_ZERO(hrtimer_bases.seq),
	.clock_base =
	{
		{
			.index = HRTIMER_BASE_MONOTONIC,
			.clockid = CLOCK_MONOTONIC,
			.get_time = &ktime_get,
                },
		{
			.index = HRTIMER_BASE_REALTIME,
			.clockid = CLOCK_REALTIME,
			.get_time = &ktime_get_real,
                },
		{
			.index = HRTIMER_BASE_BOOTTIME,
			.clockid = CLOCK_BOOTTIME,
			.get_time = &ktime_get_boottime,
                },
		{
			.index = HRTIMER_BASE_TAI,
			.clockid = CLOCK_TAI,
			.get_time = &ktime_get_clocktai,
                },
        }
};


static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
	/* Make sure we catch unsupported clockids */
	[0 ... MAX_CLOCKS - 1]	= HRTIMER_MAX_CLOCK_BASES,

	[CLOCK_REALTIME]	= HRTIMER_BASE_REALTIME,
	[CLOCK_MONOTONIC]	= HRTIMER_BASE_MONOTONIC,
	[CLOCK_BOOTTIME]	= HRTIMER_BASE_BOOTTIME,
	[CLOCK_TAI]		= HRTIMER_BASE_TAI,
};

/*
 * Functions and macros which are different for UP/SMP systems are kept in a
 * single place
 */
#ifdef CONFIG_SMP

/*
 * We require the migration_base for lock_hrtimer_base()/switch_hrtimer_base()
 * such that hrtimer_callback_running() can unconditionally dereference
 * timer->base->cpu_base
 */

static struct hrtimer_cpu_base migration_cpu_base = {
	.seq = SEQCNT_ZERO(migration_cpu_base),
	.clock_base = { { .cpu_base = &migration_cpu_base, }, },
};


#define migration_base	migration_cpu_base.clock_base[0]

/*
 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
 * means that all timers which are tied to this base via timer->base are
 * locked, and the base itself is locked too.
 *
 * So __run_timers/migrate_timers can safely modify all timers which could
 * be found on the lists/queues.
 *
 * When the timer's base is locked, and the timer removed from list, it is
 * possible to set timer->base = &migration_base and drop the lock: the timer
 * remains locked.
 */

static

struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
					     unsigned long *flags)
{
	struct hrtimer_clock_base *base;

	for (;;) {
		base = timer->base;
		if (likely(base != &migration_base)) {
			raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
			if (likely(base == timer->base))
				return base;
			/* The timer has migrated to another CPU: */
			raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
		}
		cpu_relax();
	}
}

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/*
 * With HIGHRES=y we do not migrate the timer when it is expiring
 * before the next event on the target cpu because we cannot reprogram
 * the target cpu hardware and we would cause it to fire late.
 *
 * Called with cpu_base->lock of target cpu held.
 */

static int

hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
{
#ifdef CONFIG_HIGH_RES_TIMERS
	ktime_t expires;

	if (!new_base->cpu_base->hres_active)
		return 0;

	expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
	return expires <= new_base->cpu_base->expires_next;
#else
	return 0;
#endif
}

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#ifdef CONFIG_NO_HZ_COMMON

static inline

struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
					 int pinned)
{
	if (pinned || !base->migration_enabled)
		return base;
	return &per_cpu(hrtimer_bases, get_nohz_timer_target());
}
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#else

static inline

struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
					 int pinned)
{
	return base;
}
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#endif

/*
 * We switch the timer base to a power-optimized selected CPU target,
 * if:
 *      - NO_HZ_COMMON is enabled
 *      - timer migration is enabled
 *      - the timer callback is not running
 *      - the timer is not the first expiring timer on the new target
 *
 * If one of the above requirements is not fulfilled we move the timer
 * to the current CPU or leave it on the previously assigned CPU if
 * the timer callback is currently running.
 */

static inline struct hrtimer_clock_base *

switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
		    int pinned)
{
	struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
	struct hrtimer_clock_base *new_base;
	int basenum = base->index;

	this_cpu_base = this_cpu_ptr(&hrtimer_bases);
	new_cpu_base = get_target_base(this_cpu_base, pinned);
again:
	new_base = &new_cpu_base->clock_base[basenum];

	if (base != new_base) {
		/*
                 * We are trying to move timer to new_base.
                 * However we can't change timer's base while it is running,
                 * so we keep it on the same CPU. No hassle vs. reprogramming
                 * the event source in the high resolution case. The softirq
                 * code will take care of this when the timer function has
                 * completed. There is no conflict as we hold the lock until
                 * the timer is enqueued.
                 */
		if (unlikely(hrtimer_callback_running(timer)))
			return base;

		/* See the comment in lock_hrtimer_base() */
		timer->base = &migration_base;
		raw_spin_unlock(&base->cpu_base->lock);
		raw_spin_lock(&new_base->cpu_base->lock);

		if (new_cpu_base != this_cpu_base &&
		    hrtimer_check_target(timer, new_base)) {
			raw_spin_unlock(&new_base->cpu_base->lock);
			raw_spin_lock(&base->cpu_base->lock);
			new_cpu_base = this_cpu_base;
			timer->base = base;
			goto again;
		}
		timer->base = new_base;
	} else {
		if (new_cpu_base != this_cpu_base &&
		    hrtimer_check_target(timer, new_base)) {
			new_cpu_base = this_cpu_base;
			goto again;
		}
	}
	return new_base;
}

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#else /* CONFIG_SMP */


static inline struct hrtimer_clock_base *

lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
	struct hrtimer_clock_base *base = timer->base;

	raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);

	return base;
}

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# define switch_hrtimer_base(t, b, p)	(b)

#endif	/* !CONFIG_SMP */

/*
 * Functions for the union type storage format of ktime_t which are
 * too large for inlining:
 */
#if BITS_PER_LONG < 64
/*
 * Divide a ktime value by a nanosecond value
 */


s64 __ktime_divns(const ktime_t kt, s64 div)
{
	int sft = 0;
	s64 dclc;
	u64 tmp;

	dclc = ktime_to_ns(kt);
	tmp = dclc < 0 ? -dclc : dclc;

	/* Make sure the divisor is less than 2^32: */
	while (div >> 32) {
		sft++;
		div >>= 1;
	}
	tmp >>= sft;
	do_div(tmp, (unsigned long) div);
	return dclc < 0 ? -tmp : tmp;
}
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EXPORT_SYMBOL_GPL(__ktime_divns);
#endif /* BITS_PER_LONG >= 64 */

/*
 * Add two ktime values and do a safety check for overflow:
 */


ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
{
	ktime_t res = ktime_add_unsafe(lhs, rhs);

	/*
         * We use KTIME_SEC_MAX here, the maximum timeout which we can
         * return to user space in a timespec:
         */
	if (res < 0 || res < lhs || res < rhs)
		res = ktime_set(KTIME_SEC_MAX, 0);

	return res;
}

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EXPORT_SYMBOL_GPL(ktime_add_safe);

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS


static struct debug_obj_descr hrtimer_debug_descr;



static void *hrtimer_debug_hint(void *addr)
{
	return ((struct hrtimer *) addr)->function;
}

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/*
 * fixup_init is called when:
 * - an active object is initialized
 */


static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
{
	struct hrtimer *timer = addr;

	switch (state) {
	case ODEBUG_STATE_ACTIVE:
		hrtimer_cancel(timer);
		debug_object_init(timer, &hrtimer_debug_descr);
		return true;
	default:
		return false;
	}
}

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/*
 * fixup_activate is called when:
 * - an active object is activated
 * - an unknown non-static object is activated
 */


static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
{
	switch (state) {
	case ODEBUG_STATE_ACTIVE:
		WARN_ON(1);

	default:
		return false;
	}
}

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/*
 * fixup_free is called when:
 * - an active object is freed
 */


static bool hrtimer_fixup_free(void *addr, enum debug_obj_state state)
{
	struct hrtimer *timer = addr;

	switch (state) {
	case ODEBUG_STATE_ACTIVE:
		hrtimer_cancel(timer);
		debug_object_free(timer, &hrtimer_debug_descr);
		return true;
	default:
		return false;
	}
}

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static struct debug_obj_descr hrtimer_debug_descr = {
	.name		= "hrtimer",
	.debug_hint	= hrtimer_debug_hint,
	.fixup_init	= hrtimer_fixup_init,
	.fixup_activate	= hrtimer_fixup_activate,
	.fixup_free	= hrtimer_fixup_free,
};



static inline void debug_hrtimer_init(struct hrtimer *timer)
{
	debug_object_init(timer, &hrtimer_debug_descr);
}

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static inline void debug_hrtimer_activate(struct hrtimer *timer)
{
	debug_object_activate(timer, &hrtimer_debug_descr);
}

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static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
{
	debug_object_deactivate(timer, &hrtimer_debug_descr);
}

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static inline void debug_hrtimer_free(struct hrtimer *timer)
{
	debug_object_free(timer, &hrtimer_debug_descr);
}

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static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
			   enum hrtimer_mode mode);



void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
			   enum hrtimer_mode mode)
{
	debug_object_init_on_stack(timer, &hrtimer_debug_descr);
	__hrtimer_init(timer, clock_id, mode);
}
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EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);



void destroy_hrtimer_on_stack(struct hrtimer *timer)
{
	debug_object_free(timer, &hrtimer_debug_descr);
}
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EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);

#else


static inline void debug_hrtimer_init(struct hrtimer *timer) { }
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static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
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static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
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#endif


static inline void

debug_init(struct hrtimer *timer, clockid_t clockid,
	   enum hrtimer_mode mode)
{
	debug_hrtimer_init(timer);
	trace_hrtimer_init(timer, clockid, mode);
}

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static inline void debug_activate(struct hrtimer *timer)
{
	debug_hrtimer_activate(timer);
	trace_hrtimer_start(timer);
}

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static inline void debug_deactivate(struct hrtimer *timer)
{
	debug_hrtimer_deactivate(timer);
	trace_hrtimer_cancel(timer);
}

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#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)


static inline void hrtimer_update_next_timer(struct hrtimer_cpu_base *cpu_base,
					     struct hrtimer *timer)
{
#ifdef CONFIG_HIGH_RES_TIMERS
	cpu_base->next_timer = timer;
#endif
}

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static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
{
	struct hrtimer_clock_base *base = cpu_base->clock_base;
	unsigned int active = cpu_base->active_bases;
	ktime_t expires, expires_next = KTIME_MAX;

	hrtimer_update_next_timer(cpu_base, NULL);
	for (; active; base++, active >>= 1) {
		struct timerqueue_node *next;
		struct hrtimer *timer;

		if (!(active & 0x01))
			continue;

		next = timerqueue_getnext(&base->active);
		timer = container_of(next, struct hrtimer, node);
		expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
		if (expires < expires_next) {
			expires_next = expires;
			hrtimer_update_next_timer(cpu_base, timer);
		}
	}
	/*
         * clock_was_set() might have changed base->offset of any of
         * the clock bases so the result might be negative. Fix it up
         * to prevent a false positive in clockevents_program_event().
         */
	if (expires_next < 0)
		expires_next = 0;
	return expires_next;
}
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#endif



static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
{
	ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
	ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
	ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;

	return ktime_get_update_offsets_now(&base->clock_was_set_seq,
					    offs_real, offs_boot, offs_tai);
}

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/* High resolution timer related functions */
#ifdef CONFIG_HIGH_RES_TIMERS

/*
 * High resolution timer enabled ?
 */

static bool hrtimer_hres_enabled __read_mostly  = true;

unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;

EXPORT_SYMBOL_GPL(hrtimer_resolution);

/*
 * Enable / Disable high resolution mode
 */


static int __init setup_hrtimer_hres(char *str)
{
	return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
}

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__setup("highres=", setup_hrtimer_hres);

/*
 * hrtimer_high_res_enabled - query, if the highres mode is enabled
 */


static inline int hrtimer_is_hres_enabled(void)
{
	return hrtimer_hres_enabled;
}

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/*
 * Is the high resolution mode active ?
 */


static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
{
	return cpu_base->hres_active;
}

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static inline int hrtimer_hres_active(void)
{
	return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
}

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Thomas Gleixner
18
94.74%
2
66.67%
Christoph Lameter
1
5.26%
1
33.33%
Total
19
100.00%
3
100.00%

/*
 * Reprogram the event source with checking both queues for the
 * next event
 * Called with interrupts disabled and base->lock held
 */

static void

hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
{
	ktime_t expires_next;

	if (!cpu_base->hres_active)
		return;

	expires_next = __hrtimer_get_next_event(cpu_base);

	if (skip_equal && expires_next == cpu_base->expires_next)
		return;

	cpu_base->expires_next = expires_next;

	/*
         * If a hang was detected in the last timer interrupt then we
         * leave the hang delay active in the hardware. We want the
         * system to make progress. That also prevents the following
         * scenario:
         * T1 expires 50ms from now
         * T2 expires 5s from now
         *
         * T1 is removed, so this code is called and would reprogram
         * the hardware to 5s from now. Any hrtimer_start after that
         * will not reprogram the hardware due to hang_detected being
         * set. So we'd effectivly block all timers until the T2 event
         * fires.
         */
	if (cpu_base->hang_detected)
		return;

	tick_program_event(cpu_base->expires_next, 1);
}

Contributors
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CommitProp
Thomas Gleixner
46
69.70%
4
57.14%
Ashwin Chaugule
11
16.67%
1
14.29%
Stuart Hayes
8
12.12%
1
14.29%
Arjan van de Ven
1
1.52%
1
14.29%
Total
66
100.00%
7
100.00%

/*
 * When a timer is enqueued and expires earlier than the already enqueued
 * timers, we have to check, whether it expires earlier than the timer for
 * which the clock event device was armed.
 *
 * Called with interrupts disabled and base->cpu_base.lock held
 */


static void hrtimer_reprogram(struct hrtimer *timer,
			      struct hrtimer_clock_base *base)
{
	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);

	WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);

	/*
         * If the timer is not on the current cpu, we cannot reprogram
         * the other cpus clock event device.
         */
	if (base->cpu_base != cpu_base)
		return;

	/*
         * If the hrtimer interrupt is running, then it will
         * reevaluate the clock bases and reprogram the clock event
         * device. The callbacks are always executed in hard interrupt
         * context so we don't need an extra check for a running
         * callback.
         */
	if (cpu_base->in_hrtirq)
		return;

	/*
         * CLOCK_REALTIME timer might be requested with an absolute
         * expiry time which is less than base->offset. Set it to 0.
         */
	if (expires < 0)
		expires = 0;

	if (expires >= cpu_base->expires_next)
		return;

	/* Update the pointer to the next expiring timer */
	cpu_base->next_timer = timer;

	/*
         * If a hang was detected in the last timer interrupt then we
         * do not schedule a timer which is earlier than the expiry
         * which we enforced in the hang detection. We want the system
         * to make progress.
         */
	if (cpu_base->hang_detected)
		return;

	/*
         * Program the timer hardware. We enforce the expiry for
         * events which are already in the past.
         */
	cpu_base->expires_next = expires;
	tick_program_event(expires, 1);
}

Contributors
Person
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Thomas Gleixner
111
93.28%
9
81.82%
Arjan van de Ven
6
5.04%
1
9.09%
Christoph Lameter
2
1.68%
1
9.09%
Total
119
100.00%
11
100.00%

/*
 * Initialize the high resolution related parts of cpu_base
 */


static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
{
	base->expires_next = KTIME_MAX;
	base->hang_detected = 0;
	base->hres_active = 0;
	base->next_timer = NULL;
}

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Thomas Gleixner
36
100.00%
2
100.00%
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36
100.00%
2
100.00%

/*
 * Retrigger next event is called after clock was set
 *
 * Called with interrupts disabled via on_each_cpu()
 */


static void retrigger_next_event(void *arg)
{
	struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);

	if (!base->hres_active)
		return;

	raw_spin_lock(&base->lock);
	hrtimer_update_base(base);
	hrtimer_force_reprogram(base, 0);
	raw_spin_unlock(&base->lock);
}

Contributors
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Thomas Gleixner
54
94.74%
3
60.00%
Christoph Lameter
2
3.51%
1
20.00%
John Stultz
1
1.75%
1
20.00%
Total
57
100.00%
5
100.00%

/*
 * Switch to high resolution mode
 */


static void hrtimer_switch_to_hres(void)
{
	struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);

	if (tick_init_highres()) {
		printk(KERN_WARNING "Could not switch to high resolution "
				    "mode on CPU %d\n", base->cpu);
		return;
	}
	base->hres_active = 1;
	hrtimer_resolution = HIGH_RES_NSEC;

	tick_setup_sched_timer();
	/* "Retrigger" the interrupt to get things going */
	retrigger_next_event(NULL);
}

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Thomas Gleixner
46
80.70%
3
50.00%
Ingo Molnar
9
15.79%
1
16.67%
Guenter Roeck
1
1.75%
1
16.67%
Luiz Fernando N. Capitulino
1
1.75%
1
16.67%
Total
57
100.00%
6
100.00%



static void clock_was_set_work(struct work_struct *work)
{
	clock_was_set();
}

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Thomas Gleixner
14
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1
100.00%
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14
100.00%
1
100.00%

static DECLARE_WORK(hrtimer_work, clock_was_set_work);

/*
 * Called from timekeeping and resume code to reprogram the hrtimer
 * interrupt device on all cpus.
 */


void clock_was_set_delayed(void)
{
	schedule_work(&hrtimer_work);
}

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John Stultz
10
76.92%
1
50.00%
Thomas Gleixner
3
23.08%
1
50.00%
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13
100.00%
2
100.00%

#else



static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *b) { return 0; }
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Thomas Gleixner
15
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1
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15
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1
100.00%



static inline int hrtimer_hres_active(void) { return 0; }
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Thomas Gleixner
12
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12
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1
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static inline int hrtimer_is_hres_enabled(void) { return 0; }
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Thomas Gleixner
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12
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1
100.00%



static inline void hrtimer_switch_to_hres(void) { }
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Thomas Gleixner
6
75.00%
1
50.00%
Luiz Fernando N. Capitulino
2
25.00%
1
50.00%
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8
100.00%
2
100.00%


static inline void

hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
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Thomas Gleixner
11
78.57%
1
50.00%
Ashwin Chaugule
3
21.43%
1
50.00%
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14
100.00%
2
100.00%



static inline int hrtimer_reprogram(struct hrtimer *timer,
				    struct hrtimer_clock_base *base)
{
	return 0;
}
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Thomas Gleixner
19
95.00%
1
50.00%
Viresh Kumar
1
5.00%
1
50.00%
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20
100.00%
2
100.00%



static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
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Thomas Gleixner
8
72.73%
1
50.00%
Peter Zijlstra
3
27.27%
1
50.00%
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11
100.00%
2
100.00%



static inline void retrigger_next_event(void *arg) { }

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Thomas Gleixner
10
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2
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10
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2
100.00%

#endif /* CONFIG_HIGH_RES_TIMERS */

/*
 * Clock realtime was set
 *
 * Change the offset of the realtime clock vs. the monotonic
 * clock.
 *
 * We might have to reprogram the high resolution timer interrupt. On
 * SMP we call the architecture specific code to retrigger _all_ high
 * resolution timer interrupts. On UP we just disable interrupts and
 * call the high resolution interrupt code.
 */


void clock_was_set(void)
{
#ifdef CONFIG_HIGH_RES_TIMERS
	/* Retrigger the CPU local events everywhere */
	on_each_cpu(retrigger_next_event, NULL, 1);
#endif
	timerfd_clock_was_set();
}

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Thomas Gleixner
25
100.00%
3
100.00%
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25
100.00%
3
100.00%

/*
 * During resume we might have to reprogram the high resolution timer
 * interrupt on all online CPUs.  However, all other CPUs will be
 * stopped with IRQs interrupts disabled so the clock_was_set() call
 * must be deferred.
 */


void hrtimers_resume(void)
{
	lockdep_assert_irqs_disabled();
	/* Retrigger on the local CPU */
	retrigger_next_event(NULL);
	/* And schedule a retrigger for all others */
	clock_was_set_delayed();
}

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Thomas Gleixner
19
95.00%
3
75.00%
Frédéric Weisbecker
1
5.00%
1
25.00%
Total
20
100.00%
4
100.00%

/*
 * Counterpart to lock_hrtimer_base above:
 */

static inline

void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
	raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
}

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Thomas Gleixner
33
100.00%
2
100.00%
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33
100.00%
2
100.00%

/**
 * hrtimer_forward - forward the timer expiry
 * @timer:      hrtimer to forward
 * @now:        forward past this time
 * @interval:   the interval to forward
 *
 * Forward the timer expiry so it will expire in the future.
 * Returns the number of overruns.
 *
 * Can be safely called from the callback function of @timer. If
 * called from other contexts @timer must neither be enqueued nor
 * running the callback and the caller needs to take care of
 * serialization.
 *
 * Note: This only updates the timer expiry value and does not requeue
 * the timer.
 */


u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
{
	u64 orun = 1;
	ktime_t delta;

	delta = ktime_sub(now, hrtimer_get_expires(timer));

	if (delta < 0)
		return 0;

	if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
		return 0;

	if (interval < hrtimer_resolution)
		interval = hrtimer_resolution;

	if (unlikely(delta >= interval)) {
		s64 incr = ktime_to_ns(interval);

		orun = ktime_divns(delta, incr);
		hrtimer_add_expires_ns(timer, incr * orun);
		if (hrtimer_get_expires_tv64(timer) > now)
			return orun;
		/*
                 * This (and the ktime_add() below) is the
                 * correction for exact:
                 */
		orun++;
	}
	hrtimer_add_expires(timer, interval);

	return orun;
}
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Thomas Gleixner
110
83.33%
2
40.00%
Peter Zijlstra
12
9.09%
1
20.00%
Arjan van de Ven
8
6.06%
1
20.00%
Davide Libenzi
2
1.52%
1
20.00%
Total
132
100.00%
5
100.00%


EXPORT_SYMBOL_GPL(hrtimer_forward);

/*
 * enqueue_hrtimer - internal function to (re)start a timer
 *
 * The timer is inserted in expiry order. Insertion into the
 * red black tree is O(log(n)). Must hold the base lock.
 *
 * Returns 1 when the new timer is the leftmost timer in the tree.
 */


static int enqueue_hrtimer(struct hrtimer *timer,
			   struct hrtimer_clock_base *base)
{
	debug_activate(timer);

	base->cpu_base->active_bases |= 1 << base->index;

	timer->state = HRTIMER_STATE_ENQUEUED;

	return timerqueue_add(&base->active, &timer->node);
}

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Thomas Gleixner
44
83.02%
4
50.00%
John Stultz
4
7.55%
1
12.50%
Peter Zijlstra
4
7.55%
2
25.00%
Xiao Guangrong
1
1.89%
1
12.50%
Total
53
100.00%
8
100.00%

/*
 * __remove_hrtimer - internal function to remove a timer
 *
 * Caller must hold the base lock.
 *
 * High resolution timer mode reprograms the clock event device when the
 * timer is the one which expires next. The caller can disable this by setting
 * reprogram to zero. This is useful, when the context does a reprogramming
 * anyway (e.g. timer interrupt)
 */


static void __remove_hrtimer(struct hrtimer *timer,
			     struct hrtimer_clock_base *base,
			     u8 newstate, int reprogram)
{
	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
	u8 state = timer->state;

	timer->state = newstate;
	if (!(state & HRTIMER_STATE_ENQUEUED))
		return;

	if (!timerqueue_del(&base->active, &timer->node))
		cpu_base->active_bases &= ~(1 << base->index);

#ifdef CONFIG_HIGH_RES_TIMERS
	/*
         * Note: If reprogram is false we do not update
         * cpu_base->next_timer. This happens when we remove the first
         * timer on a remote cpu. No harm as we never dereference
         * cpu_base->next_timer. So the worst thing what can happen is
         * an superflous call to hrtimer_force_reprogram() on the
         * remote cpu later on if the same timer gets enqueued again.
         */
	if (reprogram && timer == cpu_base->next_timer)
		hrtimer_force_reprogram(cpu_base, 1);
#endif
}

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Thomas Gleixner
63
59.43%
5
50.00%
Ashwin Chaugule
15
14.15%
1
10.00%
Viresh Kumar
13
12.26%
1
10.00%
Jeffrey Ohlstein
9
8.49%
1
10.00%
Peter Zijlstra
3
2.83%
1
10.00%
John Stultz
3
2.83%
1
10.00%
Total
106
100.00%
10
100.00%

/*
 * remove hrtimer, called with base lock held
 */

static inline int

remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
{
	if (hrtimer_is_queued(timer)) {
		u8 state = timer->state;
		int reprogram;

		/*
                 * Remove the timer and force reprogramming when high
                 * resolution mode is active and the timer is on the current
                 * CPU. If we remove a timer on another CPU, reprogramming is
                 * skipped. The interrupt event on this CPU is fired and
                 * reprogramming happens in the interrupt handler. This is a
                 * rare case and less expensive than a smp call.
                 */
		debug_deactivate(timer);
		reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);

		if (!restart)
			state = HRTIMER_STATE_INACTIVE;

		__remove_hrtimer(timer, base, state, reprogram);
		return 1;
	}
	return 0;
}

Contributors
Person
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CommitProp
Thomas Gleixner
61
73.49%
4
44.44%
Peter Zijlstra
13
15.66%
2
22.22%
Salman Qazi
6
7.23%
1
11.11%
Christoph Lameter
2
2.41%
1
11.11%
Xiao Guangrong
1
1.20%
1
11.11%
Total
83
100.00%
9
100.00%



static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
					    const enum hrtimer_mode mode)
{
#ifdef CONFIG_TIME_LOW_RES
	/*
         * CONFIG_TIME_LOW_RES indicates that the system has no way to return
         * granular time values. For relative timers we add hrtimer_resolution
         * (i.e. one jiffie) to prevent short timeouts.
         */
	timer->is_rel = mode & HRTIMER_MODE_REL;
	if (timer->is_rel)
		tim = ktime_add_safe(tim, hrtimer_resolution);
#endif
	return tim;
}

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Thomas Gleixner
52
100.00%
1
100.00%
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52
100.00%
1
100.00%

/**
 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
 * @timer:      the timer to be added
 * @tim:        expiry time
 * @delta_ns:   "slack" range for the timer
 * @mode:       expiry mode: absolute (HRTIMER_MODE_ABS) or
 *              relative (HRTIMER_MODE_REL)
 */


void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
			    u64 delta_ns, const enum hrtimer_mode mode)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int leftmost;

	base = lock_hrtimer_base(timer, &flags);

	/* Remove an active timer from the queue: */
	remove_hrtimer(timer, base, true);

	if (mode & HRTIMER_MODE_REL)
		tim = ktime_add_safe(tim, base->get_time());

	tim = hrtimer_update_lowres(timer, tim, mode);

	hrtimer_set_expires_range_ns(timer, tim, delta_ns);

	/* Switch the timer base, if necessary: */
	new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

	leftmost = enqueue_hrtimer(timer, new_base);
	if (!leftmost)
		goto unlock;

	if (!hrtimer_is_hres_active(timer)) {
		/*
                 * Kick to reschedule the next tick to handle the new timer
                 * on dynticks target.
                 */
		if (new_base->cpu_base->nohz_active)
			wake_up_nohz_cpu(new_base->cpu_base->cpu);
	} else {
		hrtimer_reprogram(timer, new_base);
	}
unlock:
	unlock_hrtimer_base(timer, &flags);
}
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Thomas Gleixner
98
56.65%
11
44.00%
Viresh Kumar
32
18.50%
3
12.00%
Leonid Shatz
15
8.67%
1
4.00%
Peter Zijlstra
14
8.09%
3
12.00%
Arjan van de Ven
8
4.62%
2
8.00%
Ingo Molnar
2
1.16%
1
4.00%
Roman Zippel
1
0.58%
1
4.00%
Arun R Bharadwaj
1
0.58%
1
4.00%
John Stultz
1
0.58%
1
4.00%
David Woodhouse
1
0.58%
1
4.00%
Total
173
100.00%
25
100.00%


EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);

/**
 * hrtimer_try_to_cancel - try to deactivate a timer
 * @timer:      hrtimer to stop
 *
 * Returns:
 *  0 when the timer was not active
 *  1 when the timer was active
 * -1 when the timer is currently executing the callback function and
 *    cannot be stopped
 */


int hrtimer_try_to_cancel(struct hrtimer *timer)
{
	struct hrtimer_clock_base *base;
	unsigned long flags;
	int ret = -1;

	/*
         * Check lockless first. If the timer is not active (neither
         * enqueued nor running the callback, nothing to do here.  The
         * base lock does not serialize against a concurrent enqueue,
         * so we can avoid taking it.
         */
	if (!hrtimer_active(timer))
		return 0;

	base = lock_hrtimer_base(timer, &flags);

	if (!hrtimer_callback_running(timer))
		ret = remove_hrtimer(timer, base, false);

	unlock_hrtimer_base(timer, &flags);

	return ret;

}
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Thomas Gleixner
75
97.40%
5
83.33%
Peter Zijlstra
2
2.60%
1
16.67%
Total
77
100.00%
6
100.00%


EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);

/**
 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
 * @timer:      the timer to be cancelled
 *
 * Returns:
 *  0 when the timer was not active
 *  1 when the timer was active
 */


int hrtimer_cancel(struct hrtimer *timer)
{
	for (;;) {
		int ret = hrtimer_try_to_cancel(timer);

		if (ret >= 0)
			return ret;
		cpu_relax();
	}
}
Contributors
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Thomas Gleixner
37
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2
100.00%
Total
37
100.00%
2
100.00%


EXPORT_SYMBOL_GPL(hrtimer_cancel);

/**
 * hrtimer_get_remaining - get remaining time for the timer
 * @timer:      the timer to read
 * @adjust:     adjust relative timers when CONFIG_TIME_LOW_RES=y
 */


ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
{
	unsigned long flags;
	ktime_t rem;

	lock_hrtimer_base(timer, &flags);
	if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
		rem = hrtimer_expires_remaining_adjusted(timer);
	else
		rem = hrtimer_expires_remaining(timer);
	unlock_hrtimer_base(timer, &flags);

	return rem;
}
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Thomas Gleixner
63
98.44%
3
75.00%
Arjan van de Ven
1
1.56%
1
25.00%
Total
64
100.00%
4
100.00%


EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);

#ifdef CONFIG_NO_HZ_COMMON
/**
 * hrtimer_get_next_event - get the time until next expiry event
 *
 * Returns the next expiry time or KTIME_MAX if no timer is pending.
 */


u64 hrtimer_get_next_event(void)
{
	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
	u64 expires = KTIME_MAX;
	unsigned long flags;

	raw_spin_lock_irqsave(&cpu_base->lock, flags);

	if (!__hrtimer_hres_active(cpu_base))
		expires = __hrtimer_get_next_event(cpu_base);

	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);

	return expires;
}
Contributors
Person
Tokens
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CommitProp
Thomas Gleixner
61
93.85%
7
77.78%
Christoph Lameter
2
3.08%
1
11.11%
Arjan van de Ven
2
3.08%
1
11.11%
Total
65
100.00%
9
100.00%

#endif



static inline int hrtimer_clockid_to_base(clockid_t clock_id)
{
	if (likely(clock_id < MAX_CLOCKS)) {
		int base = hrtimer_clock_to_base_table[clock_id];

		if (likely(base != HRTIMER_MAX_CLOCK_BASES))
			return base;
	}
	WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
	return HRTIMER_BASE_MONOTONIC;
}

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Marc Zyngier
53
100.00%
1
100.00%
Total
53
100.00%
1
100.00%



static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
			   enum hrtimer_mode mode)
{
	struct hrtimer_cpu_base *cpu_base;
	int base;

	memset(timer, 0, sizeof(struct hrtimer));

	cpu_base = raw_cpu_ptr(&hrtimer_bases);

	if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
		clock_id = CLOCK_MONOTONIC;

	base = hrtimer_clockid_to_base(clock_id);
	timer->base = &cpu_base->clock_base[base];
	timerqueue_init(&timer->node);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
67
76.14%
3
50.00%
John Stultz
19
21.59%
2
33.33%
Christoph Lameter
2
2.27%
1
16.67%
Total
88
100.00%
6
100.00%

/**
 * hrtimer_init - initialize a timer to the given clock
 * @timer:      the timer to be initialized
 * @clock_id:   the clock to be used
 * @mode:       timer mode abs/rel
 */


void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
		  enum hrtimer_mode mode)
{
	debug_init(timer, clock_id, mode);
	__hrtimer_init(timer, clock_id, mode);
}
Contributors
Person
Tokens
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Thomas Gleixner
30
85.71%
1
50.00%
Xiao Guangrong
5
14.29%
1
50.00%
Total
35
100.00%
2
100.00%


EXPORT_SYMBOL_GPL(hrtimer_init);

/*
 * A timer is active, when it is enqueued into the rbtree or the
 * callback function is running or it's in the state of being migrated
 * to another cpu.
 *
 * It is important for this function to not return a false negative.
 */


bool hrtimer_active(const struct hrtimer *timer)
{
	struct hrtimer_cpu_base *cpu_base;
	unsigned int seq;

	do {
		cpu_base = READ_ONCE(timer->base->cpu_base);
		seq = raw_read_seqcount_begin(&cpu_base->seq);

		if (timer->state != HRTIMER_STATE_INACTIVE ||
		    cpu_base->running == timer)
			return true;

	} while (read_seqcount_retry(&cpu_base->seq, seq) ||
		 cpu_base != READ_ONCE(timer->base->cpu_base));

	return false;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Peter Zijlstra
61
69.32%
1
25.00%
Thomas Gleixner
25
28.41%
2
50.00%
John Stultz
2
2.27%
1
25.00%
Total
88
100.00%
4
100.00%


EXPORT_SYMBOL_GPL(hrtimer_active);

/*
 * The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
 * distinct sections:
 *
 *  - queued:   the timer is queued
 *  - callback: the timer is being ran
 *  - post:     the timer is inactive or (re)queued
 *
 * On the read side we ensure we observe timer->state and cpu_base->running
 * from the same section, if anything changed while we looked at it, we retry.
 * This includes timer->base changing because sequence numbers alone are
 * insufficient for that.
 *
 * The sequence numbers are required because otherwise we could still observe
 * a false negative if the read side got smeared over multiple consequtive
 * __run_hrtimer() invocations.
 */



static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
			  struct hrtimer_clock_base *base,
			  struct hrtimer *timer, ktime_t *now)
{
	enum hrtimer_restart (*fn)(struct hrtimer *);
	int restart;

	lockdep_assert_held(&cpu_base->lock);

	debug_deactivate(timer);
	cpu_base->running = timer;

	/*
         * Separate the ->running assignment from the ->state assignment.
         *
         * As with a regular write barrier, this ensures the read side in
         * hrtimer_active() cannot observe cpu_base->running == NULL &&
         * timer->state == INACTIVE.
         */
	raw_write_seqcount_barrier(&cpu_base->seq);

	__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
	fn = timer->function;

	/*
         * Clear the 'is relative' flag for the TIME_LOW_RES case. If the
         * timer is restarted with a period then it becomes an absolute
         * timer. If its not restarted it does not matter.
         */
	if (IS_ENABLED(CONFIG_TIME_LOW_RES))
		timer->is_rel = false;

	/*
         * Because we run timers from hardirq context, there is no chance
         * they get migrated to another cpu, therefore its safe to unlock
         * the timer base.
         */
	raw_spin_unlock(&cpu_base->lock);
	trace_hrtimer_expire_entry(timer, now);
	restart = fn(timer);
	trace_hrtimer_expire_exit(timer);
	raw_spin_lock(&cpu_base->lock);

	/*
         * Note: We clear the running state after enqueue_hrtimer and
         * we do not reprogram the event hardware. Happens either in
         * hrtimer_start_range_ns() or in hrtimer_interrupt()
         *
         * Note: Because we dropped the cpu_base->lock above,
         * hrtimer_start_range_ns() can have popped in and enqueued the timer
         * for us already.
         */
	if (restart != HRTIMER_NORESTART &&
	    !(timer->state & HRTIMER_STATE_ENQUEUED))
		enqueue_hrtimer(timer, base);

	/*
         * Separate the ->running assignment from the ->state assignment.
         *
         * As with a regular write barrier, this ensures the read side in
         * hrtimer_active() cannot observe cpu_base->running == NULL &&
         * timer->state == INACTIVE.
         */
	raw_write_seqcount_barrier(&cpu_base->seq);

	WARN_ON_ONCE(cpu_base->running != timer);
	cpu_base->running = NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Peter Zijlstra
87
47.80%
5
31.25%
Thomas Gleixner
61
33.52%
6
37.50%
Xiao Guangrong
17
9.34%
1
6.25%
Tony Lindgren
8
4.40%
1
6.25%
Salman Qazi
6
3.30%
1
6.25%
Gautham R. Shenoy
2
1.10%
1
6.25%
Pratyush Patel
1
0.55%
1
6.25%
Total
182
100.00%
16
100.00%



static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
{
	struct hrtimer_clock_base *base = cpu_base->clock_base;
	unsigned int active = cpu_base->active_bases;

	for (; active; base++, active >>= 1) {
		struct timerqueue_node *node;
		ktime_t basenow;

		if (!(active & 0x01))
			continue;

		basenow = ktime_add(now, base->offset);

		while ((node = timerqueue_getnext(&base->active))) {
			struct hrtimer *timer;

			timer = container_of(node, struct hrtimer, node);

			/*
                         * The immediate goal for using the softexpires is
                         * minimizing wakeups, not running timers at the
                         * earliest interrupt after their soft expiration.
                         * This allows us to avoid using a Priority Search
                         * Tree, which can answer a stabbing querry for
                         * overlapping intervals and instead use the simple
                         * BST we already have.
                         * We don't add extra wakeups by delaying timers that
                         * are right-of a not yet expired timer, because that
                         * timer will have to trigger a wakeup anyway.
                         */
			if (basenow < hrtimer_get_softexpires_tv64(timer))
				break;

			__run_hrtimer(cpu_base, base, timer, &basenow);
		}
	}
}

Contributors
Person
Tokens
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Commits
CommitProp
Thomas Gleixner
67
51.54%
5
38.46%
Peter Zijlstra
38
29.23%
1
7.69%
Salman Qazi
7
5.38%
1
7.69%
John Stultz
6
4.62%
1
7.69%
George Anzinger
4
3.08%
1
7.69%
Arjan van de Ven
4
3.08%
2
15.38%
Xiao Guangrong
3
2.31%
1
7.69%
Frédéric Weisbecker
1
0.77%
1
7.69%
Total
130
100.00%
13
100.00%

#ifdef CONFIG_HIGH_RES_TIMERS

/*
 * High resolution timer interrupt
 * Called with interrupts disabled
 */


void hrtimer_interrupt(struct clock_event_device *dev)
{
	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
	ktime_t expires_next, now, entry_time, delta;
	int retries = 0;

	BUG_ON(!cpu_base->hres_active);
	cpu_base->nr_events++;
	dev->next_event = KTIME_MAX;

	raw_spin_lock(&cpu_base->lock);
	entry_time = now = hrtimer_update_base(cpu_base);
retry:
	cpu_base->in_hrtirq = 1;
	/*
         * We set expires_next to KTIME_MAX here with cpu_base->lock
         * held to prevent that a timer is enqueued in our queue via
         * the migration code. This does not affect enqueueing of
         * timers which run their callback and need to be requeued on
         * this CPU.
         */
	cpu_base->expires_next = KTIME_MAX;

	__hrtimer_run_queues(cpu_base, now);

	/* Reevaluate the clock bases for the next expiry */
	expires_next = __hrtimer_get_next_event(cpu_base);
	/*
         * Store the new expiry value so the migration code can verify
         * against it.
         */
	cpu_base->expires_next = expires_next;
	cpu_base->in_hrtirq = 0;
	raw_spin_unlock(&cpu_base->lock);

	/* Reprogramming necessary ? */
	if (!tick_program_event(expires_next, 0)) {
		cpu_base->hang_detected = 0;
		return;
	}

	/*
         * The next timer was already expired due to:
         * - tracing
         * - long lasting callbacks
         * - being scheduled away when running in a VM
         *
         * We need to prevent that we loop forever in the hrtimer
         * interrupt routine. We give it 3 attempts to avoid
         * overreacting on some spurious event.
         *
         * Acquire base lock for updating the offsets and retrieving
         * the current time.
         */
	raw_spin_lock(&cpu_base->lock);
	now = hrtimer_update_base(cpu_base);
	cpu_base->nr_retries++;
	if (++retries < 3)
		goto retry;
	/*
         * Give the system a chance to do something else than looping
         * here. We stored the entry time, so we know exactly how long
         * we spent here. We schedule the next event this amount of
         * time away.
         */
	cpu_base->nr_hangs++;
	cpu_base->hang_detected = 1;
	raw_spin_unlock(&cpu_base->lock);
	delta = ktime_sub(now, entry_time);
	if ((unsigned int)delta > cpu_base->max_hang_time)
		cpu_base->max_hang_time = (unsigned int) delta;
	/*
         * Limit it to a sensible value as we enforce a longer
         * delay. Give the CPU at least 100ms to catch up.
         */
	if (delta > 100 * NSEC_PER_MSEC)
		expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
	else
		expires_next = ktime_add(now, delta);
	tick_program_event(expires_next, 1);
	printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
		    ktime_to_ns(delta));
}

Contributors
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CommitProp
Thomas Gleixner
214
78.68%
9
56.25%
Peter Zijlstra
39
14.34%
1
6.25%
John Stultz
9
3.31%
1
6.25%
Frédéric Weisbecker
3
1.10%
1
6.25%
George Anzinger
2
0.74%
1
6.25%
Christoph Lameter
2
0.74%
1
6.25%
Stephen Hemminger
2
0.74%
1
6.25%
Xiao Guangrong
1
0.37%
1
6.25%
Total
272
100.00%
16
100.00%

/* called with interrupts disabled */


static inline void __hrtimer_peek_ahead_timers(void)
{
	struct tick_device *td;

	if (!hrtimer_hres_active())
		return;

	td = this_cpu_ptr(&tick_cpu_device);
	if (td && td->evtdev)
		hrtimer_interrupt(td->evtdev);
}

Contributors
Person
Tokens
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Commits
CommitProp
Arjan van de Ven
34
77.27%
2
33.33%
Thomas Gleixner
8
18.18%
3
50.00%
Christoph Lameter
2
4.55%
1
16.67%
Total
44
100.00%
6
100.00%

#else /* CONFIG_HIGH_RES_TIMERS */



static inline void __hrtimer_peek_ahead_timers(void) { }

Contributors
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Ingo Molnar
8
100.00%
1
100.00%
Total
8
100.00%
1
100.00%

#endif	/* !CONFIG_HIGH_RES_TIMERS */

/*
 * Called from run_local_timers in hardirq context every jiffy
 */


void hrtimer_run_queues(void)
{
	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
	ktime_t now;

	if (__hrtimer_hres_active(cpu_base))
		return;

	/*
         * This _is_ ugly: We have to check periodically, whether we
         * can switch to highres and / or nohz mode. The clocksource
         * switch happens with xtime_lock held. Notification from
         * there only sets the check bit in the tick_oneshot code,
         * otherwise we might deadlock vs. xtime_lock.
         */
	if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
		hrtimer_switch_to_hres();
		return;
	}

	raw_spin_lock(&cpu_base->lock);
	now = hrtimer_update_base(cpu_base);
	__hrtimer_run_queues(cpu_base, now);
	raw_spin_unlock(&cpu_base->lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
53
70.67%
9
60.00%
Dimitri Sivanich
16
21.33%
2
13.33%
Christoph Lameter
2
2.67%
1
6.67%
John Stultz
2
2.67%
1
6.67%
Xiao Guangrong
1
1.33%
1
6.67%
Peter Zijlstra
1
1.33%
1
6.67%
Total
75
100.00%
15
100.00%

/*
 * Sleep related functions:
 */


static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
{
	struct hrtimer_sleeper *t =
		container_of(timer, struct hrtimer_sleeper, timer);
	struct task_struct *task = t->task;

	t->task = NULL;
	if (task)
		wake_up_process(task);

	return HRTIMER_NORESTART;
}

Contributors
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Thomas Gleixner
54
100.00%
2
100.00%
Total
54
100.00%
2
100.00%



void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
{
	sl->timer.function = hrtimer_wakeup;
	sl->task = task;
}
Contributors
Person
Tokens
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CommitProp
Thomas Gleixner
27
93.10%
1
50.00%
Ingo Molnar
2
6.90%
1
50.00%
Total
29
100.00%
2
100.00%


EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);



int nanosleep_copyout(struct restart_block *restart, struct timespec64 *ts)
{
	switch(restart->nanosleep.type) {
#ifdef CONFIG_COMPAT
	case TT_COMPAT:
		if (compat_put_timespec64(ts, restart->nanosleep.compat_rmtp))
			return -EFAULT;
		break;
#endif
	case TT_NATIVE:
		if (put_timespec64(ts, restart->nanosleep.rmtp))
			return -EFAULT;
		break;
	default:
		BUG();
	}
	return -ERESTART_RESTARTBLOCK;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
75
93.75%
1
50.00%
Deepa Dinamani
5
6.25%
1
50.00%
Total
80
100.00%
2
100.00%



static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
{
	struct restart_block *restart;

	hrtimer_init_sleeper(t, current);

	do {
		set_current_state(TASK_INTERRUPTIBLE);
		hrtimer_start_expires(&t->timer, mode);

		if (likely(t->task))
			freezable_schedule();

		hrtimer_cancel(&t->timer);
		mode = HRTIMER_MODE_ABS;

	} while (t->task && !signal_pending(current));

	__set_current_state(TASK_RUNNING);

	if (!t->task)
		return 0;

	restart = &current->restart_block;
	if (restart->nanosleep.type != TT_NONE) {
		ktime_t rem = hrtimer_expires_remaining(&t->timer);
		struct timespec64 rmt;

		if (rem <= 0)
			return 0;
		rmt = ktime_to_timespec64(rem);

		return nanosleep_copyout(restart, &rmt);
	}
	return -ERESTART_RESTARTBLOCK;
}

Contributors
Person
Tokens
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Commits
CommitProp
Thomas Gleixner
43
26.71%
4
28.57%
Al Viro
42
26.09%
3
21.43%
Roman Zippel
34
21.12%
1
7.14%
Oleg Nesterov
30
18.63%
1
7.14%
Peter Zijlstra
7
4.35%
2
14.29%
Arjan van de Ven
2
1.24%
1
7.14%
Deepa Dinamani
2
1.24%
1
7.14%
Colin Cross
1
0.62%
1
7.14%
Total
161
100.00%
14
100.00%



static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
	struct hrtimer_sleeper t;
	int ret;

	hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
				HRTIMER_MODE_ABS);
	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);

	ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
46
65.71%
6
46.15%
Roman Zippel
10
14.29%
1
7.69%
Arjan van de Ven
5
7.14%
1
7.69%
Al Viro
3
4.29%
2
15.38%
George Anzinger
3
4.29%
1
7.69%
Oleg Nesterov
2
2.86%
1
7.69%
Toyo Abe
1
1.43%
1
7.69%
Total
70
100.00%
13
100.00%



long hrtimer_nanosleep(const struct timespec64 *rqtp,
		       const enum hrtimer_mode mode, const clockid_t clockid)
{
	struct restart_block *restart;
	struct hrtimer_sleeper t;
	int ret = 0;
	u64 slack;

	slack = current->timer_slack_ns;
	if (dl_task(current) || rt_task(current))
		slack = 0;

	hrtimer_init_on_stack(&t.timer, clockid, mode);
	hrtimer_set_expires_range_ns(&t.timer, timespec64_to_ktime(*rqtp), slack);
	ret = do_nanosleep(&t, mode);
	if (ret != -ERESTART_RESTARTBLOCK)
		goto out;

	/* Absolute timers do not update the rmtp value and restart: */
	if (mode == HRTIMER_MODE_ABS) {
		ret = -ERESTARTNOHAND;
		goto out;
	}

	restart = &current->restart_block;
	restart->fn = hrtimer_nanosleep_restart;
	restart->nanosleep.clockid = t.timer.base->clockid;
	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
out:
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

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CommitProp
Thomas Gleixner
106
59.55%
7
38.89%
Arjan van de Ven
30
16.85%
2
11.11%
Al Viro
13
7.30%
2
11.11%
Roman Zippel
11
6.18%
1
5.56%
George Anzinger
6
3.37%
1
5.56%
Dario Faggioli
5
2.81%
1
5.56%
Toyo Abe
3
1.69%
1
5.56%
Deepa Dinamani
2
1.12%
1
5.56%
Oleg Nesterov
1
0.56%
1
5.56%
John Stultz
1
0.56%
1
5.56%
Total
178
100.00%
18
100.00%


SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
		struct timespec __user *, rmtp)
{
	struct timespec64 tu;

	if (get_timespec64(&tu, rqtp))
		return -EFAULT;

	if (!timespec64_valid(&tu))
		return -EINVAL;

	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
	current->restart_block.nanosleep.rmtp = rmtp;
	return hrtimer_nanosleep(&tu, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}

#ifdef CONFIG_COMPAT


COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp,
		       struct compat_timespec __user *, rmtp)
{
	struct timespec64 tu;

	if (compat_get_timespec64(&tu, rqtp))
		return -EFAULT;

	if (!timespec64_valid(&tu))
		return -EINVAL;

	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
	current->restart_block.nanosleep.compat_rmtp = rmtp;
	return hrtimer_nanosleep(&tu, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}
#endif

/*
 * Functions related to boot-time initialization:
 */


int hrtimers_prepare_cpu(unsigned int cpu)
{
	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
	int i;

	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
		cpu_base->clock_base[i].cpu_base = cpu_base;
		timerqueue_init_head(&cpu_base->clock_base[i].active);
	}

	cpu_base->active_bases = 0;
	cpu_base->cpu = cpu;
	hrtimer_init_hres(cpu_base);
	return 0;
}

Contributors
Person
Tokens
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CommitProp
Thomas Gleixner
63
75.00%
5
71.43%
John Stultz
15
17.86%
1
14.29%
Viresh Kumar
6
7.14%
1
14.29%
Total
84
100.00%
7
100.00%

#ifdef CONFIG_HOTPLUG_CPU



static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
				struct hrtimer_clock_base *new_base)
{
	struct hrtimer *timer;
	struct timerqueue_node *node;

	while ((node = timerqueue_getnext(&old_base->active))) {
		timer = container_of(node, struct hrtimer, node);
		BUG_ON(hrtimer_callback_running(timer));
		debug_deactivate(timer);

		/*
                 * Mark it as ENQUEUED not INACTIVE otherwise the
                 * timer could be seen as !active and just vanish away
                 * under us on another CPU
                 */
		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
		timer->base = new_base;
		/*
                 * Enqueue the timers on the new cpu. This does not
                 * reprogram the event device in case the timer
                 * expires before the earliest on this CPU, but we run
                 * hrtimer_interrupt after we migrated everything to
                 * sort out already expired timers and reprogram the
                 * event device.
                 */
		enqueue_hrtimer(timer, new_base);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
86
92.47%
8
66.67%
John Stultz
3
3.23%
1
8.33%
Oleg Nesterov
2
2.15%
1
8.33%
Peter Zijlstra
1
1.08%
1
8.33%
Xiao Guangrong
1
1.08%
1
8.33%
Total
93
100.00%
12
100.00%



int hrtimers_dead_cpu(unsigned int scpu)
{
	struct hrtimer_cpu_base *old_base, *new_base;
	int i;

	BUG_ON(cpu_online(scpu));
	tick_cancel_sched_timer(scpu);

	local_irq_disable();
	old_base = &per_cpu(hrtimer_bases, scpu);
	new_base = this_cpu_ptr(&hrtimer_bases);
	/*
         * The caller is globally serialized and nobody else
         * takes two locks at once, deadlock is not possible.
         */
	raw_spin_lock(&new_base->lock);
	raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);

	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
		migrate_hrtimer_list(&old_base->clock_base[i],
				     &new_base->clock_base[i]);
	}

	raw_spin_unlock(&old_base->lock);
	raw_spin_unlock(&new_base->lock);

	/* Check, if we got expired work to do */
	__hrtimer_peek_ahead_timers();
	local_irq_enable();
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
116
87.22%
5
50.00%
Oleg Nesterov
10
7.52%
2
20.00%
Peter Zijlstra
4
3.01%
1
10.00%
Christoph Lameter
2
1.50%
1
10.00%
Heiko Carstens
1
0.75%
1
10.00%
Total
133
100.00%
10
100.00%

#endif /* CONFIG_HOTPLUG_CPU */



void __init hrtimers_init(void)
{
	hrtimers_prepare_cpu(smp_processor_id());
}

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Thomas Gleixner
14
100.00%
2
100.00%
Total
14
100.00%
2
100.00%

/**
 * schedule_hrtimeout_range_clock - sleep until timeout
 * @expires:    timeout value (ktime_t)
 * @delta:      slack in expires timeout (ktime_t)
 * @mode:       timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
 * @clock:      timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
 */

int __sched

schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
			       const enum hrtimer_mode mode, int clock)
{
	struct hrtimer_sleeper t;

	/*
         * Optimize when a zero timeout value is given. It does not
         * matter whether this is an absolute or a relative time.
         */
	if (expires && *expires == 0) {
		__set_current_state(TASK_RUNNING);
		return 0;
	}

	/*
         * A NULL parameter means "infinite"
         */
	if (!expires) {
		schedule();
		return -EINTR;
	}

	hrtimer_init_on_stack(&t.timer, clock, mode);
	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);

	hrtimer_init_sleeper(&t, current);

	hrtimer_start_expires(&t.timer, mode);

	if (likely(t.task))
		schedule();

	hrtimer_cancel(&t.timer);
	destroy_hrtimer_on_stack(&t.timer);

	__set_current_state(TASK_RUNNING);

	return !t.task ? 0 : -EINTR;
}

Contributors
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CommitProp
Arjan van de Ven
137
93.20%
3
42.86%
Carsten Emde
5
3.40%
1
14.29%
Thomas Gleixner
3
2.04%
1
14.29%
John Stultz
1
0.68%
1
14.29%
Namhyung Kim
1
0.68%
1
14.29%
Total
147
100.00%
7
100.00%

/**
 * schedule_hrtimeout_range - sleep until timeout
 * @expires:    timeout value (ktime_t)
 * @delta:      slack in expires timeout (ktime_t)
 * @mode:       timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
 *
 * Make the current task sleep until the given expiry time has
 * elapsed. The routine will return immediately unless
 * the current task state has been set (see set_current_state()).
 *
 * The @delta argument gives the kernel the freedom to schedule the
 * actual wakeup to a time that is both power and performance friendly.
 * The kernel give the normal best effort behavior for "@expires+@delta",
 * but may decide to fire the timer earlier, but no earlier than @expires.
 *
 * You can set the task state as follows -
 *
 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
 * pass before the routine returns unless the current task is explicitly
 * woken up, (e.g. by wake_up_process()).
 *
 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
 * delivered to the current task or the current task is explicitly woken
 * up.
 *
 * The current task state is guaranteed to be TASK_RUNNING when this
 * routine returns.
 *
 * Returns 0 when the timer has expired. If the task was woken before the
 * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
 * by an explicit wakeup, it returns -EINTR.
 */


int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
				     const enum hrtimer_mode mode)
{
	return schedule_hrtimeout_range_clock(expires, delta, mode,
					      CLOCK_MONOTONIC);
}
Contributors
Person
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CommitProp
Carsten Emde
29
96.67%
1
50.00%
John Stultz
1
3.33%
1
50.00%
Total
30
100.00%
2
100.00%


EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);

/**
 * schedule_hrtimeout - sleep until timeout
 * @expires:    timeout value (ktime_t)
 * @mode:       timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
 *
 * Make the current task sleep until the given expiry time has
 * elapsed. The routine will return immediately unless
 * the current task state has been set (see set_current_state()).
 *
 * You can set the task state as follows -
 *
 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
 * pass before the routine returns unless the current task is explicitly
 * woken up, (e.g. by wake_up_process()).
 *
 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
 * delivered to the current task or the current task is explicitly woken
 * up.
 *
 * The current task state is guaranteed to be TASK_RUNNING when this
 * routine returns.
 *
 * Returns 0 when the timer has expired. If the task was woken before the
 * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
 * by an explicit wakeup, it returns -EINTR.
 */


int __sched schedule_hrtimeout(ktime_t *expires,
			       const enum hrtimer_mode mode)
{
	return schedule_hrtimeout_range(expires, 0, mode);
}
Contributors
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Tokens
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CommitProp
Arjan van de Ven
25
100.00%
1
100.00%
Total
25
100.00%
1
100.00%


EXPORT_SYMBOL_GPL(schedule_hrtimeout);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Gleixner
3658
66.84%
59
34.30%
Peter Zijlstra
334
6.10%
11
6.40%
Arjan van de Ven
278
5.08%
7
4.07%
Al Viro
242
4.42%
5
2.91%
John Stultz
164
3.00%
8
4.65%
Xiao Guangrong
110
2.01%
1
0.58%
Marc Zyngier
64
1.17%
1
0.58%
Roman Zippel
57
1.04%
3
1.74%
Viresh Kumar
52
0.95%
5
2.91%
Arun R Bharadwaj
49
0.90%
2
1.16%
Oleg Nesterov
46
0.84%
4
2.33%
Carsten Emde
35
0.64%
1
0.58%
Ingo Molnar
32
0.58%
7
4.07%
Ashwin Chaugule
29
0.53%
1
0.58%
Stanislaw Gruszka
28
0.51%
1
0.58%
Stephen Hemminger
24
0.44%
2
1.16%
Leon Ma
21
0.38%
1
0.58%
Salman Qazi
19
0.35%
1
0.58%
Christoph Lameter
19
0.35%
3
1.74%
Deepa Dinamani
17
0.31%
2
1.16%
Dimitri Sivanich
16
0.29%
2
1.16%
Frédéric Weisbecker
16
0.29%
5
2.91%
Leonid Shatz
15
0.27%
1
0.58%
George Anzinger
15
0.27%
1
0.58%
Heiko Carstens
13
0.24%
2
1.16%
Michael Bohan
10
0.18%
1
0.58%
Changbin Du
9
0.16%
2
1.16%
Jeffrey Ohlstein
9
0.16%
1
0.58%
Stuart Hayes
8
0.15%
1
0.58%
Kees Cook
8
0.15%
1
0.58%
Dario Faggioli
8
0.15%
1
0.58%
Tony Lindgren
8
0.15%
1
0.58%
Guenter Roeck
6
0.11%
2
1.16%
Clark Williams
6
0.11%
2
1.16%
Artem B. Bityutskiy
5
0.09%
1
0.58%
Stas Sergeev
5
0.09%
1
0.58%
Toyo Abe
4
0.07%
1
0.58%
Colin Cross
4
0.07%
1
0.58%
Pratyush Patel
4
0.07%
2
1.16%
Luiz Fernando N. Capitulino
3
0.05%
1
0.58%
Davide Libenzi
2
0.04%
1
0.58%
Russell King
2
0.04%
1
0.58%
Gautham R. Shenoy
2
0.04%
1
0.58%
Jan Blunck
2
0.04%
1
0.58%
Douglas Anderson
2
0.04%
1
0.58%
Nico Pitre
2
0.04%
1
0.58%
Fengguang Wu
1
0.02%
1
0.58%
Masanari Iida
1
0.02%
1
0.58%
Zhen Lei
1
0.02%
1
0.58%
Vegard Nossum
1
0.02%
1
0.58%
Namhyung Kim
1
0.02%
1
0.58%
David Woodhouse
1
0.02%
1
0.58%
Linus Torvalds
1
0.02%
1
0.58%
Stephen Boyd
1
0.02%
1
0.58%
Paul Gortmaker
1
0.02%
1
0.58%
Uwe Kleine-König
1
0.02%
1
0.58%
Mike Frysinger
1
0.02%
1
0.58%
Total
5473
100.00%
172
100.00%
Directory: kernel/time

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