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![John Stultz](/assets/img/avatar_default.png)
Add hrtimer support for CLOCK_TAI, as well as posix timer interfaces. Signed-off-by: John Stultz <john.stultz@linaro.org>
464 lines
14 KiB
C
464 lines
14 KiB
C
/*
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* include/linux/hrtimer.h
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*
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* hrtimers - High-resolution kernel timers
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*
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* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
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*
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* data type definitions, declarations, prototypes
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*
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* Started by: Thomas Gleixner and Ingo Molnar
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*
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* For licencing details see kernel-base/COPYING
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*/
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#ifndef _LINUX_HRTIMER_H
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#define _LINUX_HRTIMER_H
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#include <linux/rbtree.h>
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#include <linux/ktime.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/wait.h>
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#include <linux/percpu.h>
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#include <linux/timer.h>
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#include <linux/timerqueue.h>
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struct hrtimer_clock_base;
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struct hrtimer_cpu_base;
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/*
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* Mode arguments of xxx_hrtimer functions:
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*/
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enum hrtimer_mode {
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HRTIMER_MODE_ABS = 0x0, /* Time value is absolute */
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HRTIMER_MODE_REL = 0x1, /* Time value is relative to now */
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HRTIMER_MODE_PINNED = 0x02, /* Timer is bound to CPU */
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HRTIMER_MODE_ABS_PINNED = 0x02,
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HRTIMER_MODE_REL_PINNED = 0x03,
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};
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/*
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* Return values for the callback function
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*/
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enum hrtimer_restart {
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HRTIMER_NORESTART, /* Timer is not restarted */
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HRTIMER_RESTART, /* Timer must be restarted */
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};
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/*
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* Values to track state of the timer
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*
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* Possible states:
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*
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* 0x00 inactive
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* 0x01 enqueued into rbtree
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* 0x02 callback function running
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* 0x04 timer is migrated to another cpu
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*
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* Special cases:
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* 0x03 callback function running and enqueued
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* (was requeued on another CPU)
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* 0x05 timer was migrated on CPU hotunplug
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*
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* The "callback function running and enqueued" status is only possible on
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* SMP. It happens for example when a posix timer expired and the callback
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* queued a signal. Between dropping the lock which protects the posix timer
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* and reacquiring the base lock of the hrtimer, another CPU can deliver the
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* signal and rearm the timer. We have to preserve the callback running state,
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* as otherwise the timer could be removed before the softirq code finishes the
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* the handling of the timer.
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*
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* The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state
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* to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This
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* also affects HRTIMER_STATE_MIGRATE where the preservation is not
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* necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is
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* enqueued on the new cpu.
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*
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* All state transitions are protected by cpu_base->lock.
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*/
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#define HRTIMER_STATE_INACTIVE 0x00
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#define HRTIMER_STATE_ENQUEUED 0x01
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#define HRTIMER_STATE_CALLBACK 0x02
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#define HRTIMER_STATE_MIGRATE 0x04
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/**
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* struct hrtimer - the basic hrtimer structure
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* @node: timerqueue node, which also manages node.expires,
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* the absolute expiry time in the hrtimers internal
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* representation. The time is related to the clock on
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* which the timer is based. Is setup by adding
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* slack to the _softexpires value. For non range timers
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* identical to _softexpires.
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* @_softexpires: the absolute earliest expiry time of the hrtimer.
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* The time which was given as expiry time when the timer
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* was armed.
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* @function: timer expiry callback function
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* @base: pointer to the timer base (per cpu and per clock)
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* @state: state information (See bit values above)
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* @start_site: timer statistics field to store the site where the timer
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* was started
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* @start_comm: timer statistics field to store the name of the process which
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* started the timer
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* @start_pid: timer statistics field to store the pid of the task which
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* started the timer
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*
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* The hrtimer structure must be initialized by hrtimer_init()
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*/
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struct hrtimer {
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struct timerqueue_node node;
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ktime_t _softexpires;
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enum hrtimer_restart (*function)(struct hrtimer *);
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struct hrtimer_clock_base *base;
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unsigned long state;
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#ifdef CONFIG_TIMER_STATS
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int start_pid;
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void *start_site;
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char start_comm[16];
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#endif
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};
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/**
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* struct hrtimer_sleeper - simple sleeper structure
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* @timer: embedded timer structure
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* @task: task to wake up
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*
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* task is set to NULL, when the timer expires.
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*/
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struct hrtimer_sleeper {
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struct hrtimer timer;
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struct task_struct *task;
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};
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/**
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* struct hrtimer_clock_base - the timer base for a specific clock
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* @cpu_base: per cpu clock base
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* @index: clock type index for per_cpu support when moving a
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* timer to a base on another cpu.
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* @clockid: clock id for per_cpu support
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* @active: red black tree root node for the active timers
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* @resolution: the resolution of the clock, in nanoseconds
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* @get_time: function to retrieve the current time of the clock
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* @softirq_time: the time when running the hrtimer queue in the softirq
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* @offset: offset of this clock to the monotonic base
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*/
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struct hrtimer_clock_base {
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struct hrtimer_cpu_base *cpu_base;
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int index;
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clockid_t clockid;
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struct timerqueue_head active;
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ktime_t resolution;
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ktime_t (*get_time)(void);
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ktime_t softirq_time;
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ktime_t offset;
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};
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enum hrtimer_base_type {
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HRTIMER_BASE_MONOTONIC,
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HRTIMER_BASE_REALTIME,
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HRTIMER_BASE_BOOTTIME,
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HRTIMER_BASE_TAI,
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HRTIMER_MAX_CLOCK_BASES,
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};
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/*
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* struct hrtimer_cpu_base - the per cpu clock bases
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* @lock: lock protecting the base and associated clock bases
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* and timers
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* @active_bases: Bitfield to mark bases with active timers
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* @clock_was_set: Indicates that clock was set from irq context.
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* @expires_next: absolute time of the next event which was scheduled
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* via clock_set_next_event()
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* @hres_active: State of high resolution mode
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* @hang_detected: The last hrtimer interrupt detected a hang
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* @nr_events: Total number of hrtimer interrupt events
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* @nr_retries: Total number of hrtimer interrupt retries
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* @nr_hangs: Total number of hrtimer interrupt hangs
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* @max_hang_time: Maximum time spent in hrtimer_interrupt
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* @clock_base: array of clock bases for this cpu
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*/
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struct hrtimer_cpu_base {
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raw_spinlock_t lock;
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unsigned int active_bases;
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unsigned int clock_was_set;
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#ifdef CONFIG_HIGH_RES_TIMERS
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ktime_t expires_next;
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int hres_active;
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int hang_detected;
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unsigned long nr_events;
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unsigned long nr_retries;
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unsigned long nr_hangs;
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ktime_t max_hang_time;
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#endif
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struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
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};
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static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
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{
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timer->node.expires = time;
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timer->_softexpires = time;
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}
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static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
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{
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timer->_softexpires = time;
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timer->node.expires = ktime_add_safe(time, delta);
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}
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static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
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{
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timer->_softexpires = time;
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timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
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}
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static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
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{
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timer->node.expires.tv64 = tv64;
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timer->_softexpires.tv64 = tv64;
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}
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static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
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{
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timer->node.expires = ktime_add_safe(timer->node.expires, time);
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timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
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}
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static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
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{
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timer->node.expires = ktime_add_ns(timer->node.expires, ns);
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timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
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}
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static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
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{
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return timer->node.expires;
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}
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static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
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{
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return timer->_softexpires;
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}
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static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
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{
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return timer->node.expires.tv64;
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}
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static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
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{
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return timer->_softexpires.tv64;
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}
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static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
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{
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return ktime_to_ns(timer->node.expires);
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}
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static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
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{
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return ktime_sub(timer->node.expires, timer->base->get_time());
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}
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#ifdef CONFIG_HIGH_RES_TIMERS
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struct clock_event_device;
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extern void hrtimer_interrupt(struct clock_event_device *dev);
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/*
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* In high resolution mode the time reference must be read accurate
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*/
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static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
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{
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return timer->base->get_time();
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}
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static inline int hrtimer_is_hres_active(struct hrtimer *timer)
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{
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return timer->base->cpu_base->hres_active;
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}
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extern void hrtimer_peek_ahead_timers(void);
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/*
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* The resolution of the clocks. The resolution value is returned in
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* the clock_getres() system call to give application programmers an
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* idea of the (in)accuracy of timers. Timer values are rounded up to
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* this resolution values.
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*/
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# define HIGH_RES_NSEC 1
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# define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
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# define MONOTONIC_RES_NSEC HIGH_RES_NSEC
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# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
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extern void clock_was_set_delayed(void);
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#else
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# define MONOTONIC_RES_NSEC LOW_RES_NSEC
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# define KTIME_MONOTONIC_RES KTIME_LOW_RES
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static inline void hrtimer_peek_ahead_timers(void) { }
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/*
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* In non high resolution mode the time reference is taken from
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* the base softirq time variable.
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*/
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static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
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{
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return timer->base->softirq_time;
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}
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static inline int hrtimer_is_hres_active(struct hrtimer *timer)
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{
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return 0;
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}
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static inline void clock_was_set_delayed(void) { }
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#endif
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extern void clock_was_set(void);
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#ifdef CONFIG_TIMERFD
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extern void timerfd_clock_was_set(void);
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#else
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static inline void timerfd_clock_was_set(void) { }
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#endif
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extern void hrtimers_resume(void);
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extern ktime_t ktime_get(void);
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extern ktime_t ktime_get_real(void);
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extern ktime_t ktime_get_boottime(void);
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extern ktime_t ktime_get_monotonic_offset(void);
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extern ktime_t ktime_get_clocktai(void);
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extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot,
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ktime_t *offs_tai);
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DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
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/* Exported timer functions: */
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/* Initialize timers: */
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extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
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enum hrtimer_mode mode);
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
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enum hrtimer_mode mode);
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extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
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#else
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static inline void hrtimer_init_on_stack(struct hrtimer *timer,
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clockid_t which_clock,
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enum hrtimer_mode mode)
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{
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hrtimer_init(timer, which_clock, mode);
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}
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static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
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#endif
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/* Basic timer operations: */
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extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
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const enum hrtimer_mode mode);
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extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
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unsigned long range_ns, const enum hrtimer_mode mode);
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extern int
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__hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
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unsigned long delta_ns,
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const enum hrtimer_mode mode, int wakeup);
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extern int hrtimer_cancel(struct hrtimer *timer);
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extern int hrtimer_try_to_cancel(struct hrtimer *timer);
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static inline int hrtimer_start_expires(struct hrtimer *timer,
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enum hrtimer_mode mode)
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{
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unsigned long delta;
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ktime_t soft, hard;
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soft = hrtimer_get_softexpires(timer);
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hard = hrtimer_get_expires(timer);
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delta = ktime_to_ns(ktime_sub(hard, soft));
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return hrtimer_start_range_ns(timer, soft, delta, mode);
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}
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static inline int hrtimer_restart(struct hrtimer *timer)
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{
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return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
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}
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/* Query timers: */
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extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
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extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
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extern ktime_t hrtimer_get_next_event(void);
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/*
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* A timer is active, when it is enqueued into the rbtree or the
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* callback function is running or it's in the state of being migrated
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* to another cpu.
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*/
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static inline int hrtimer_active(const struct hrtimer *timer)
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{
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return timer->state != HRTIMER_STATE_INACTIVE;
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}
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/*
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* Helper function to check, whether the timer is on one of the queues
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*/
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static inline int hrtimer_is_queued(struct hrtimer *timer)
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{
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return timer->state & HRTIMER_STATE_ENQUEUED;
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}
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/*
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* Helper function to check, whether the timer is running the callback
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* function
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*/
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static inline int hrtimer_callback_running(struct hrtimer *timer)
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{
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return timer->state & HRTIMER_STATE_CALLBACK;
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}
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/* Forward a hrtimer so it expires after now: */
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extern u64
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hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
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/* Forward a hrtimer so it expires after the hrtimer's current now */
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static inline u64 hrtimer_forward_now(struct hrtimer *timer,
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ktime_t interval)
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{
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return hrtimer_forward(timer, timer->base->get_time(), interval);
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}
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/* Precise sleep: */
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extern long hrtimer_nanosleep(struct timespec *rqtp,
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struct timespec __user *rmtp,
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const enum hrtimer_mode mode,
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const clockid_t clockid);
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extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
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extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
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struct task_struct *tsk);
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extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
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const enum hrtimer_mode mode);
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extern int schedule_hrtimeout_range_clock(ktime_t *expires,
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unsigned long delta, const enum hrtimer_mode mode, int clock);
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extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
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/* Soft interrupt function to run the hrtimer queues: */
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extern void hrtimer_run_queues(void);
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extern void hrtimer_run_pending(void);
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/* Bootup initialization: */
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extern void __init hrtimers_init(void);
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#if BITS_PER_LONG < 64
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extern u64 ktime_divns(const ktime_t kt, s64 div);
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#else /* BITS_PER_LONG < 64 */
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# define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
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#endif
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/* Show pending timers: */
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extern void sysrq_timer_list_show(void);
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#endif
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