45f1ff59e2
Add a new pointer argument to cpuidle_select() and to the ->select
cpuidle governor callback to allow a boolean value indicating
whether or not the tick should be stopped before entering the
selected state to be returned from there.
Make the ladder governor ignore that pointer (to preserve its
current behavior) and make the menu governor return 'false" through
it if:
(1) the idle exit latency is constrained at 0, or
(2) the selected state is a polling one, or
(3) the expected idle period duration is within the tick period
range.
In addition to that, the correction factor computations in the menu
governor need to take the possibility that the tick may not be
stopped into account to avoid artificially small correction factor
values. To that end, add a mechanism to record tick wakeups, as
suggested by Peter Zijlstra, and use it to modify the menu_update()
behavior when tick wakeup occurs. Namely, if the CPU is woken up by
the tick and the return value of tick_nohz_get_sleep_length() is not
within the tick boundary, the predicted idle duration is likely too
short, so make menu_update() try to compensate for that by updating
the governor statistics as though the CPU was idle for a long time.
Since the value returned through the new argument pointer of
cpuidle_select() is not used by its caller yet, this change by
itself is not expected to alter the functionality of the code.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
282 lines
8.5 KiB
C
282 lines
8.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Tick related global functions
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*/
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#ifndef _LINUX_TICK_H
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#define _LINUX_TICK_H
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#include <linux/clockchips.h>
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#include <linux/irqflags.h>
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#include <linux/percpu.h>
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#include <linux/context_tracking_state.h>
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#include <linux/cpumask.h>
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#include <linux/sched.h>
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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extern void __init tick_init(void);
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/* Should be core only, but ARM BL switcher requires it */
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extern void tick_suspend_local(void);
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/* Should be core only, but XEN resume magic and ARM BL switcher require it */
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extern void tick_resume_local(void);
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extern void tick_handover_do_timer(void);
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extern void tick_cleanup_dead_cpu(int cpu);
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#else /* CONFIG_GENERIC_CLOCKEVENTS */
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static inline void tick_init(void) { }
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static inline void tick_suspend_local(void) { }
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static inline void tick_resume_local(void) { }
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static inline void tick_handover_do_timer(void) { }
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static inline void tick_cleanup_dead_cpu(int cpu) { }
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#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
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#if defined(CONFIG_GENERIC_CLOCKEVENTS) && defined(CONFIG_SUSPEND)
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extern void tick_freeze(void);
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extern void tick_unfreeze(void);
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#else
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static inline void tick_freeze(void) { }
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static inline void tick_unfreeze(void) { }
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#endif
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#ifdef CONFIG_TICK_ONESHOT
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extern void tick_irq_enter(void);
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# ifndef arch_needs_cpu
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# define arch_needs_cpu() (0)
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# endif
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# else
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static inline void tick_irq_enter(void) { }
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#endif
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#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
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extern void hotplug_cpu__broadcast_tick_pull(int dead_cpu);
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#else
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static inline void hotplug_cpu__broadcast_tick_pull(int dead_cpu) { }
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#endif
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enum tick_broadcast_mode {
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TICK_BROADCAST_OFF,
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TICK_BROADCAST_ON,
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TICK_BROADCAST_FORCE,
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};
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enum tick_broadcast_state {
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TICK_BROADCAST_EXIT,
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TICK_BROADCAST_ENTER,
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};
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
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extern void tick_broadcast_control(enum tick_broadcast_mode mode);
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#else
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static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { }
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#endif /* BROADCAST */
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
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#else
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static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
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{
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return 0;
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}
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#endif
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static inline void tick_broadcast_enable(void)
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{
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tick_broadcast_control(TICK_BROADCAST_ON);
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}
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static inline void tick_broadcast_disable(void)
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{
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tick_broadcast_control(TICK_BROADCAST_OFF);
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}
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static inline void tick_broadcast_force(void)
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{
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tick_broadcast_control(TICK_BROADCAST_FORCE);
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}
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static inline int tick_broadcast_enter(void)
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{
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return tick_broadcast_oneshot_control(TICK_BROADCAST_ENTER);
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}
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static inline void tick_broadcast_exit(void)
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{
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tick_broadcast_oneshot_control(TICK_BROADCAST_EXIT);
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}
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enum tick_dep_bits {
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TICK_DEP_BIT_POSIX_TIMER = 0,
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TICK_DEP_BIT_PERF_EVENTS = 1,
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TICK_DEP_BIT_SCHED = 2,
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TICK_DEP_BIT_CLOCK_UNSTABLE = 3
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};
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#define TICK_DEP_MASK_NONE 0
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#define TICK_DEP_MASK_POSIX_TIMER (1 << TICK_DEP_BIT_POSIX_TIMER)
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#define TICK_DEP_MASK_PERF_EVENTS (1 << TICK_DEP_BIT_PERF_EVENTS)
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#define TICK_DEP_MASK_SCHED (1 << TICK_DEP_BIT_SCHED)
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#define TICK_DEP_MASK_CLOCK_UNSTABLE (1 << TICK_DEP_BIT_CLOCK_UNSTABLE)
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#ifdef CONFIG_NO_HZ_COMMON
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extern bool tick_nohz_enabled;
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extern bool tick_nohz_tick_stopped(void);
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extern bool tick_nohz_tick_stopped_cpu(int cpu);
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extern void tick_nohz_idle_stop_tick(void);
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extern void tick_nohz_idle_restart_tick(void);
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extern void tick_nohz_idle_enter(void);
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extern void tick_nohz_idle_exit(void);
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extern void tick_nohz_irq_exit(void);
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extern bool tick_nohz_idle_got_tick(void);
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extern ktime_t tick_nohz_get_sleep_length(void);
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extern unsigned long tick_nohz_get_idle_calls(void);
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extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu);
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extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
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extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
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static inline void tick_nohz_idle_stop_tick_protected(void)
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{
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local_irq_disable();
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tick_nohz_idle_stop_tick();
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local_irq_enable();
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}
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#else /* !CONFIG_NO_HZ_COMMON */
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#define tick_nohz_enabled (0)
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static inline int tick_nohz_tick_stopped(void) { return 0; }
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static inline int tick_nohz_tick_stopped_cpu(int cpu) { return 0; }
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static inline void tick_nohz_idle_stop_tick(void) { }
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static inline void tick_nohz_idle_restart_tick(void) { }
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static inline void tick_nohz_idle_enter(void) { }
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static inline void tick_nohz_idle_exit(void) { }
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static inline bool tick_nohz_idle_got_tick(void) { return false; }
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static inline ktime_t tick_nohz_get_sleep_length(void)
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{
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return NSEC_PER_SEC / HZ;
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}
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static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
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static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
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static inline void tick_nohz_idle_stop_tick_protected(void) { }
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#endif /* !CONFIG_NO_HZ_COMMON */
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#ifdef CONFIG_NO_HZ_FULL
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extern bool tick_nohz_full_running;
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extern cpumask_var_t tick_nohz_full_mask;
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static inline bool tick_nohz_full_enabled(void)
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{
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if (!context_tracking_is_enabled())
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return false;
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return tick_nohz_full_running;
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}
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static inline bool tick_nohz_full_cpu(int cpu)
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{
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if (!tick_nohz_full_enabled())
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return false;
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return cpumask_test_cpu(cpu, tick_nohz_full_mask);
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}
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static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask)
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{
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if (tick_nohz_full_enabled())
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cpumask_or(mask, mask, tick_nohz_full_mask);
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}
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extern void tick_nohz_dep_set(enum tick_dep_bits bit);
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extern void tick_nohz_dep_clear(enum tick_dep_bits bit);
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extern void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit);
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extern void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit);
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extern void tick_nohz_dep_set_task(struct task_struct *tsk,
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enum tick_dep_bits bit);
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extern void tick_nohz_dep_clear_task(struct task_struct *tsk,
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enum tick_dep_bits bit);
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extern void tick_nohz_dep_set_signal(struct signal_struct *signal,
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enum tick_dep_bits bit);
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extern void tick_nohz_dep_clear_signal(struct signal_struct *signal,
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enum tick_dep_bits bit);
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/*
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* The below are tick_nohz_[set,clear]_dep() wrappers that optimize off-cases
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* on top of static keys.
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*/
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static inline void tick_dep_set(enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_set(bit);
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}
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static inline void tick_dep_clear(enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_clear(bit);
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}
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static inline void tick_dep_set_cpu(int cpu, enum tick_dep_bits bit)
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{
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if (tick_nohz_full_cpu(cpu))
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tick_nohz_dep_set_cpu(cpu, bit);
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}
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static inline void tick_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
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{
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if (tick_nohz_full_cpu(cpu))
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tick_nohz_dep_clear_cpu(cpu, bit);
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}
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static inline void tick_dep_set_task(struct task_struct *tsk,
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enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_set_task(tsk, bit);
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}
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static inline void tick_dep_clear_task(struct task_struct *tsk,
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enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_clear_task(tsk, bit);
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}
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static inline void tick_dep_set_signal(struct signal_struct *signal,
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enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_set_signal(signal, bit);
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}
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static inline void tick_dep_clear_signal(struct signal_struct *signal,
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enum tick_dep_bits bit)
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{
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if (tick_nohz_full_enabled())
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tick_nohz_dep_clear_signal(signal, bit);
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}
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extern void tick_nohz_full_kick_cpu(int cpu);
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extern void __tick_nohz_task_switch(void);
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extern void __init tick_nohz_full_setup(cpumask_var_t cpumask);
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#else
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static inline bool tick_nohz_full_enabled(void) { return false; }
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static inline bool tick_nohz_full_cpu(int cpu) { return false; }
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static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { }
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static inline void tick_dep_set(enum tick_dep_bits bit) { }
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static inline void tick_dep_clear(enum tick_dep_bits bit) { }
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static inline void tick_dep_set_cpu(int cpu, enum tick_dep_bits bit) { }
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static inline void tick_dep_clear_cpu(int cpu, enum tick_dep_bits bit) { }
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static inline void tick_dep_set_task(struct task_struct *tsk,
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enum tick_dep_bits bit) { }
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static inline void tick_dep_clear_task(struct task_struct *tsk,
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enum tick_dep_bits bit) { }
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static inline void tick_dep_set_signal(struct signal_struct *signal,
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enum tick_dep_bits bit) { }
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static inline void tick_dep_clear_signal(struct signal_struct *signal,
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enum tick_dep_bits bit) { }
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static inline void tick_nohz_full_kick_cpu(int cpu) { }
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static inline void __tick_nohz_task_switch(void) { }
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static inline void tick_nohz_full_setup(cpumask_var_t cpumask) { }
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#endif
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static inline void tick_nohz_task_switch(void)
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{
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if (tick_nohz_full_enabled())
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__tick_nohz_task_switch();
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}
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#endif
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