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f268c3737e
Checking for and processing RCU-nocb deferred wakeup upon user/guest entry is only relevant when nohz_full runs on the local CPU, otherwise the periodic tick should take care of it. Make sure we don't needlessly pollute these fast-paths as a -3% performance regression on a will-it-scale.per_process_ops has been reported so far. Fixes:47b8ff194c(entry: Explicitly flush pending rcuog wakeup before last rescheduling point) Fixes:4ae7dc97f7(entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point) Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210527113441.465489-1-frederic@kernel.org
310 lines
9.6 KiB
C
310 lines
9.6 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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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_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 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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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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