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543 lines
16 KiB
543 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
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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 <[email protected]> |
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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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#ifndef _LINUX_HRTIMER_H |
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#define _LINUX_HRTIMER_H |
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#include <linux/hrtimer_defs.h> |
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#include <linux/rbtree.h> |
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#include <linux/init.h> |
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#include <linux/list.h> |
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#include <linux/percpu.h> |
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#include <linux/seqlock.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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* HRTIMER_MODE_ABS - Time value is absolute |
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* HRTIMER_MODE_REL - Time value is relative to now |
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* HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered |
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* when starting the timer) |
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* HRTIMER_MODE_SOFT - Timer callback function will be executed in |
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* soft irq context |
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* HRTIMER_MODE_HARD - Timer callback function will be executed in |
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* hard irq context even on PREEMPT_RT. |
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*/ |
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enum hrtimer_mode { |
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HRTIMER_MODE_ABS = 0x00, |
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HRTIMER_MODE_REL = 0x01, |
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HRTIMER_MODE_PINNED = 0x02, |
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HRTIMER_MODE_SOFT = 0x04, |
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HRTIMER_MODE_HARD = 0x08, |
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HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED, |
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HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED, |
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HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT, |
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HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT, |
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HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT, |
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HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT, |
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HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD, |
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HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD, |
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HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD, |
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HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD, |
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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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* |
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* The callback state is not part of the timer->state because clearing it would |
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* mean touching the timer after the callback, this makes it impossible to free |
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* the timer from the callback function. |
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* |
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* Therefore we track the callback state in: |
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* |
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* timer->base->cpu_base->running == timer |
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* |
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* On SMP it is possible to have a "callback function running and enqueued" |
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* status. 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. |
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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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/** |
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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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* @is_rel: Set if the timer was armed relative |
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* @is_soft: Set if hrtimer will be expired in soft interrupt context. |
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* @is_hard: Set if hrtimer will be expired in hard interrupt context |
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* even on RT. |
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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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u8 state; |
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u8 is_rel; |
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u8 is_soft; |
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u8 is_hard; |
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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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#ifdef CONFIG_64BIT |
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# define __hrtimer_clock_base_align ____cacheline_aligned |
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#else |
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# define __hrtimer_clock_base_align |
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#endif |
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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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* @seq: seqcount around __run_hrtimer |
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* @running: pointer to the currently running hrtimer |
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* @active: red black tree root node for the active timers |
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* @get_time: function to retrieve the current time of the clock |
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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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unsigned int index; |
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clockid_t clockid; |
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seqcount_raw_spinlock_t seq; |
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struct hrtimer *running; |
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struct timerqueue_head active; |
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ktime_t (*get_time)(void); |
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ktime_t offset; |
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} __hrtimer_clock_base_align; |
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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_BASE_MONOTONIC_SOFT, |
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HRTIMER_BASE_REALTIME_SOFT, |
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HRTIMER_BASE_BOOTTIME_SOFT, |
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HRTIMER_BASE_TAI_SOFT, |
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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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* @cpu: cpu number |
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* @active_bases: Bitfield to mark bases with active timers |
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* @clock_was_set_seq: Sequence counter of clock was set events |
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* @hres_active: State of high resolution mode |
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* @in_hrtirq: hrtimer_interrupt() is currently executing |
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* @hang_detected: The last hrtimer interrupt detected a hang |
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* @softirq_activated: displays, if the softirq is raised - update of softirq |
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* related settings is not required then. |
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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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* @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are |
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* expired |
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* @timer_waiters: A hrtimer_cancel() invocation waits for the timer |
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* callback to finish. |
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* @expires_next: absolute time of the next event, is required for remote |
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* hrtimer enqueue; it is the total first expiry time (hard |
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* and soft hrtimer are taken into account) |
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* @next_timer: Pointer to the first expiring timer |
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* @softirq_expires_next: Time to check, if soft queues needs also to be expired |
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* @softirq_next_timer: Pointer to the first expiring softirq based timer |
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* @clock_base: array of clock bases for this cpu |
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* |
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* Note: next_timer is just an optimization for __remove_hrtimer(). |
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* Do not dereference the pointer because it is not reliable on |
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* cross cpu removals. |
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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 cpu; |
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unsigned int active_bases; |
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unsigned int clock_was_set_seq; |
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unsigned int hres_active : 1, |
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in_hrtirq : 1, |
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hang_detected : 1, |
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softirq_activated : 1; |
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#ifdef CONFIG_HIGH_RES_TIMERS |
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unsigned int nr_events; |
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unsigned short nr_retries; |
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unsigned short nr_hangs; |
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unsigned int max_hang_time; |
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#endif |
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#ifdef CONFIG_PREEMPT_RT |
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spinlock_t softirq_expiry_lock; |
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atomic_t timer_waiters; |
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#endif |
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ktime_t expires_next; |
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struct hrtimer *next_timer; |
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ktime_t softirq_expires_next; |
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struct hrtimer *softirq_next_timer; |
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struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
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} ____cacheline_aligned; |
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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, u64 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; |
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timer->_softexpires = 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; |
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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; |
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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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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 IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ? |
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timer->base->cpu_base->hres_active : 0; |
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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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extern void clock_was_set_delayed(void); |
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extern unsigned int hrtimer_resolution; |
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#else |
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#define hrtimer_resolution (unsigned int)LOW_RES_NSEC |
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static inline void clock_was_set_delayed(void) { } |
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#endif |
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static inline ktime_t |
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__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now) |
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{ |
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ktime_t rem = ktime_sub(timer->node.expires, now); |
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/* |
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* Adjust relative timers for the extra we added in |
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* hrtimer_start_range_ns() to prevent short timeouts. |
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*/ |
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if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel) |
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rem -= hrtimer_resolution; |
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return rem; |
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} |
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static inline ktime_t |
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hrtimer_expires_remaining_adjusted(const struct hrtimer *timer) |
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{ |
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return __hrtimer_expires_remaining_adjusted(timer, |
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timer->base->get_time()); |
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} |
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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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DECLARE_PER_CPU(struct tick_device, tick_cpu_device); |
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#ifdef CONFIG_PREEMPT_RT |
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void hrtimer_cancel_wait_running(const struct hrtimer *timer); |
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#else |
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static inline void hrtimer_cancel_wait_running(struct hrtimer *timer) |
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{ |
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cpu_relax(); |
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} |
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#endif |
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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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extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id, |
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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 hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, |
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clockid_t clock_id, |
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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 hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, |
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clockid_t clock_id, |
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enum hrtimer_mode mode) |
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{ |
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hrtimer_init_sleeper(sl, clock_id, 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 void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
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u64 range_ns, const enum hrtimer_mode mode); |
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/** |
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* hrtimer_start - (re)start an hrtimer |
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* @timer: the timer to be added |
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* @tim: expiry time |
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* @mode: timer mode: absolute (HRTIMER_MODE_ABS) or |
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* relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED); |
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* softirq based mode is considered for debug purpose only! |
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*/ |
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static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim, |
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const enum hrtimer_mode mode) |
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{ |
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hrtimer_start_range_ns(timer, tim, 0, mode); |
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} |
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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 void hrtimer_start_expires(struct hrtimer *timer, |
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enum hrtimer_mode mode) |
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{ |
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u64 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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hrtimer_start_range_ns(timer, soft, delta, mode); |
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} |
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void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl, |
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enum hrtimer_mode mode); |
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static inline void hrtimer_restart(struct hrtimer *timer) |
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{ |
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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, bool adjust); |
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/** |
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* hrtimer_get_remaining - get remaining time for the timer |
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* @timer: the timer to read |
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*/ |
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static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) |
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{ |
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return __hrtimer_get_remaining(timer, false); |
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} |
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extern u64 hrtimer_get_next_event(void); |
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extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); |
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extern bool hrtimer_active(const struct hrtimer *timer); |
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/** |
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* hrtimer_is_queued - check, whether the timer is on one of the queues |
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* @timer: Timer to check |
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* |
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* Returns: True if the timer is queued, false otherwise |
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* |
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* The function can be used lockless, but it gives only a current snapshot. |
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*/ |
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static inline bool hrtimer_is_queued(struct hrtimer *timer) |
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{ |
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/* The READ_ONCE pairs with the update functions of timer->state */ |
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return !!(READ_ONCE(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->base->running == timer; |
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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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/** |
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* hrtimer_forward_now - forward the timer expiry so it expires after now |
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* @timer: hrtimer to forward |
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* @interval: the interval to forward |
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* |
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* Forward the timer expiry so it will expire after the current time |
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* of the hrtimer clock base. Returns the number of overruns. |
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* |
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* Can be safely called from the callback function of @timer. If |
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* called from other contexts @timer must neither be enqueued nor |
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* running the callback and the caller needs to take care of |
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* serialization. |
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* |
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* Note: This only updates the timer expiry value and does not requeue |
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* the timer. |
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*/ |
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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 int nanosleep_copyout(struct restart_block *, struct timespec64 *); |
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extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode, |
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const clockid_t clockid); |
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extern int schedule_hrtimeout_range(ktime_t *expires, u64 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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u64 delta, |
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const enum hrtimer_mode mode, |
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clockid_t clock_id); |
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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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/* Bootup initialization: */ |
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extern void __init hrtimers_init(void); |
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/* Show pending timers: */ |
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extern void sysrq_timer_list_show(void); |
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int hrtimers_prepare_cpu(unsigned int cpu); |
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#ifdef CONFIG_HOTPLUG_CPU |
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int hrtimers_dead_cpu(unsigned int cpu); |
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#else |
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#define hrtimers_dead_cpu NULL |
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#endif |
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#endif
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