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![Linus Torvalds](/assets/img/avatar_default.png)
- Micro-optimize tick_nohz_full_cpu() - Optimize idle exit tick restarts to be less eager - Optimize tick_nohz_dep_set_task() to only wake up a single CPU. This reduces IPIs and interruptions on nohz_full CPUs. - Optimize tick_nohz_dep_set_signal() in a similar fashion. - Skip IPIs in tick_nohz_kick_task() when trying to kick a non-running task. - Micro-optimize tick_nohz_task_switch() IRQ flags handling to reduce context switching costs. - Misc cleanups and fixes Signed-off-by: Ingo Molnar <mingo@kernel.org> -----BEGIN PGP SIGNATURE----- iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmDZcycRHG1pbmdvQGtl cm5lbC5vcmcACgkQEnMQ0APhK1jItRAAn1/vI0+pWQWjyWQ+CL8AMNNWTbtBpC7W ZUR+IEtEoYEufYXH9RgcweIgopBExVlC9CWzUX5o7AuVdN2YyzcBuQbza4vlYeIm azcdIlKCwjdgODJBTgHNH7IR0QKF/Gq+fVCGX3Xc37BlyD389CQ33HXC7X2JZLB3 Mb5wxAJoZ2HQzGGJoz4JyA0rl6lY3jYzLMK7mqxkUqIqT45xLpgw5+imRM2J1ddV d/73P4TwFY+E8KXSLctUfgmkmCzJYISGSlH49jX3CkwAktwTY17JjWjxT9Z5b2D8 6TTpsDoLtI4tXg0U2KsBxBoDHK/a4hAwo+GnE/RMT6ghqaX5IrANrgtTVPBN9dvh qUGVAMHVDN3Ed7wwFvCm4tPUz/iXzBsP8xPl28WPHsyV9BE9tcrk2ynzSWy47Twd z1GVZDNTwCfdvH62WS/HvbPdGl2hHH5/oe3HaF1ROLPHq8UzaxwKEX+A0rwLJrBp ZU8Lnvu3rPVa5cHc4z1AE7sbX7OkTTNjxY/qQzDhNKwVwfkaPcBiok9VgEIEGS7A n3U/yuQCn307sr7SlJ6z4yu3YCw3aEJ3pTxUprmNTh3+x4yF5ZaOimqPyvzBaUVM Hm3LYrxHIScisFJio4FiC2dghZryM37RFonvqrCAOuA+afMU2GOFnaoDruXU27SE tqxR6c/hw+4= =18pN -----END PGP SIGNATURE----- Merge tag 'timers-nohz-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timers/nohz updates from Ingo Molnar: - Micro-optimize tick_nohz_full_cpu() - Optimize idle exit tick restarts to be less eager - Optimize tick_nohz_dep_set_task() to only wake up a single CPU. This reduces IPIs and interruptions on nohz_full CPUs. - Optimize tick_nohz_dep_set_signal() in a similar fashion. - Skip IPIs in tick_nohz_kick_task() when trying to kick a non-running task. - Micro-optimize tick_nohz_task_switch() IRQ flags handling to reduce context switching costs. - Misc cleanups and fixes * tag 'timers-nohz-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS: Add myself as context tracking maintainer tick/nohz: Call tick_nohz_task_switch() with interrupts disabled tick/nohz: Kick only _queued_ task whose tick dependency is updated tick/nohz: Change signal tick dependency to wake up CPUs of member tasks tick/nohz: Only wake up a single target cpu when kicking a task tick/nohz: Update nohz_full Kconfig help tick/nohz: Update idle_exittime on actual idle exit tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE tick/nohz: Conditionally restart tick on idle exit tick/nohz: Evaluate the CPU expression after the static key
314 lines
9.7 KiB
C
314 lines
9.7 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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#include <linux/rcupdate.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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#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_HOTPLUG_CPU)
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extern void tick_offline_cpu(unsigned int cpu);
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#else
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static inline void tick_offline_cpu(unsigned int cpu) { }
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#endif
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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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TICK_DEP_BIT_RCU = 4,
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TICK_DEP_BIT_RCU_EXP = 5
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};
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#define TICK_DEP_BIT_MAX TICK_DEP_BIT_RCU_EXP
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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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#define TICK_DEP_MASK_RCU (1 << TICK_DEP_BIT_RCU)
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#define TICK_DEP_MASK_RCU_EXP (1 << TICK_DEP_BIT_RCU_EXP)
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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_retain_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_next_hrtimer(void);
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extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next);
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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_retain_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_next_hrtimer(void)
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{
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/* Next wake up is the tick period, assume it starts now */
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return ktime_add(ktime_get(), TICK_NSEC);
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}
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static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
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{
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*delta_next = TICK_NSEC;
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return *delta_next;
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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_enabled())
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return false;
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return tick_nohz_full_running;
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}
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/*
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* Check if a CPU is part of the nohz_full subset. Arrange for evaluating
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* the cpu expression (typically smp_processor_id()) _after_ the static
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* key.
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*/
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#define tick_nohz_full_cpu(_cpu) ({ \
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bool __ret = false; \
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if (tick_nohz_full_enabled()) \
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__ret = cpumask_test_cpu((_cpu), tick_nohz_full_mask); \
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__ret; \
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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 task_struct *tsk,
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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 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_signal(tsk, 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_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit) { }
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static inline void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit) { }
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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 task_struct *tsk,
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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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static inline void tick_nohz_user_enter_prepare(void)
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{
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if (tick_nohz_full_cpu(smp_processor_id()))
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rcu_nocb_flush_deferred_wakeup();
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}
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#endif
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