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![Frederic Weisbecker](/assets/img/avatar_default.png)
When a task is scheduled in, it may have some properties of its own that could make the CPU reconsider the need for the tick: posix cpu timers, perf events, ... So notify the full dynticks subsystem when a task gets scheduled in and re-check the tick dependency at this stage. This is done through a self IPI to avoid messing up with any current lock scenario. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
183 lines
5.6 KiB
C
183 lines
5.6 KiB
C
/* linux/include/linux/tick.h
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*
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* This file contains the structure definitions for tick related functions
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*
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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/hrtimer.h>
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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enum tick_device_mode {
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TICKDEV_MODE_PERIODIC,
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TICKDEV_MODE_ONESHOT,
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};
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struct tick_device {
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struct clock_event_device *evtdev;
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enum tick_device_mode mode;
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};
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enum tick_nohz_mode {
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NOHZ_MODE_INACTIVE,
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NOHZ_MODE_LOWRES,
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NOHZ_MODE_HIGHRES,
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};
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/**
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* struct tick_sched - sched tick emulation and no idle tick control/stats
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* @sched_timer: hrtimer to schedule the periodic tick in high
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* resolution mode
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* @last_tick: Store the last tick expiry time when the tick
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* timer is modified for nohz sleeps. This is necessary
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* to resume the tick timer operation in the timeline
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* when the CPU returns from nohz sleep.
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* @tick_stopped: Indicator that the idle tick has been stopped
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* @idle_jiffies: jiffies at the entry to idle for idle time accounting
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* @idle_calls: Total number of idle calls
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* @idle_sleeps: Number of idle calls, where the sched tick was stopped
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* @idle_entrytime: Time when the idle call was entered
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* @idle_waketime: Time when the idle was interrupted
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* @idle_exittime: Time when the idle state was left
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* @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
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* @iowait_sleeptime: Sum of the time slept in idle with sched tick stopped, with IO outstanding
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* @sleep_length: Duration of the current idle sleep
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* @do_timer_lst: CPU was the last one doing do_timer before going idle
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*/
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struct tick_sched {
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struct hrtimer sched_timer;
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unsigned long check_clocks;
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enum tick_nohz_mode nohz_mode;
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ktime_t last_tick;
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int inidle;
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int tick_stopped;
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unsigned long idle_jiffies;
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unsigned long idle_calls;
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unsigned long idle_sleeps;
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int idle_active;
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ktime_t idle_entrytime;
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ktime_t idle_waketime;
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ktime_t idle_exittime;
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ktime_t idle_sleeptime;
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ktime_t iowait_sleeptime;
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ktime_t sleep_length;
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unsigned long last_jiffies;
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unsigned long next_jiffies;
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ktime_t idle_expires;
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int do_timer_last;
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};
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extern void __init tick_init(void);
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extern int tick_is_oneshot_available(void);
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extern struct tick_device *tick_get_device(int cpu);
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# ifdef CONFIG_HIGH_RES_TIMERS
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extern int tick_init_highres(void);
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extern int tick_program_event(ktime_t expires, int force);
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extern void tick_setup_sched_timer(void);
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# endif
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# if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
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extern void tick_cancel_sched_timer(int cpu);
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# else
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static inline void tick_cancel_sched_timer(int cpu) { }
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# endif
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# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
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extern struct tick_device *tick_get_broadcast_device(void);
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extern struct cpumask *tick_get_broadcast_mask(void);
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# ifdef CONFIG_TICK_ONESHOT
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extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
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# endif
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# endif /* BROADCAST */
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# ifdef CONFIG_TICK_ONESHOT
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extern void tick_clock_notify(void);
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extern int tick_check_oneshot_change(int allow_nohz);
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extern struct tick_sched *tick_get_tick_sched(int cpu);
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extern void tick_check_idle(int cpu);
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extern int tick_oneshot_mode_active(void);
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# ifndef arch_needs_cpu
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# define arch_needs_cpu(cpu) (0)
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# endif
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# else
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static inline void tick_clock_notify(void) { }
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static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
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static inline void tick_check_idle(int cpu) { }
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static inline int tick_oneshot_mode_active(void) { return 0; }
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# endif
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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_cancel_sched_timer(int cpu) { }
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static inline void tick_clock_notify(void) { }
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static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
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static inline void tick_check_idle(int cpu) { }
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static inline int tick_oneshot_mode_active(void) { return 0; }
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#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
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# ifdef CONFIG_NO_HZ_COMMON
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DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
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static inline int tick_nohz_tick_stopped(void)
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{
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return __this_cpu_read(tick_cpu_sched.tick_stopped);
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}
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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 ktime_t tick_nohz_get_sleep_length(void);
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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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# else /* !CONFIG_NO_HZ_COMMON */
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static inline int tick_nohz_tick_stopped(void)
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{
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return 0;
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}
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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 ktime_t tick_nohz_get_sleep_length(void)
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{
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ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
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return len;
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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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# endif /* !CONFIG_NO_HZ_COMMON */
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#ifdef CONFIG_NO_HZ_FULL
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extern void tick_nohz_init(void);
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extern int tick_nohz_full_cpu(int cpu);
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extern void tick_nohz_full_check(void);
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extern void tick_nohz_full_kick(void);
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extern void tick_nohz_full_kick_all(void);
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extern void tick_nohz_task_switch(struct task_struct *tsk);
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#else
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static inline void tick_nohz_init(void) { }
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static inline int tick_nohz_full_cpu(int cpu) { return 0; }
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static inline void tick_nohz_full_check(void) { }
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static inline void tick_nohz_full_kick(void) { }
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static inline void tick_nohz_full_kick_all(void) { }
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static inline void tick_nohz_task_switch(struct task_struct *tsk) { }
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#endif
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# ifdef CONFIG_CPU_IDLE_GOV_MENU
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extern void menu_hrtimer_cancel(void);
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# else
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static inline void menu_hrtimer_cancel(void) {}
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# endif /* CONFIG_CPU_IDLE_GOV_MENU */
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#endif
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