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%
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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);
}

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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);
}

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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);
}

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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
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14
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1
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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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15
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15
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static inline int hrtimer_hres_active(void) { return 0; }
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12
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12
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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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static inline void hrtimer_switch_to_hres(void) { }
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Thomas Gleixner
6
75.00%
1
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Luiz Fernando N. Capitulino
2
25.00%
1
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8
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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
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14
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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
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11
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2
100.00%



static inline void retrigger_next_event(void *arg) { }

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Thomas Gleixner
10
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10
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#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
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3
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25
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3
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/*
 * 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
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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