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alistair23-linux/include/linux/tick.h
Frederic Weisbecker a80e49e2cc nohz: Move nohz full init call to tick init 
This way we unbloat a bit main.c and more importantly we initialize
nohz full after init_IRQ(). This dependency will be needed in further
patches because nohz full needs irq work to raise its own IRQ.
Information about the support for this ability on ARM64 is obtained on
init_IRQ() which initialize the pointer to __smp_call_function.

Since tick_init() is called right after init_IRQ(), this is a good place
to call tick_nohz_init() and prepare for that dependency.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-13 18:34:44 +02:00

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/* linux/include/linux/tick.h
*
* This file contains the structure definitions for tick related functions
*
*/
#ifndef _LINUX_TICK_H
#define _LINUX_TICK_H
#include <linux/clockchips.h>
#include <linux/irqflags.h>
#include <linux/percpu.h>
#include <linux/hrtimer.h>
#include <linux/context_tracking_state.h>
#include <linux/cpumask.h>
#include <linux/sched.h>
#ifdef CONFIG_GENERIC_CLOCKEVENTS
enum tick_device_mode {
TICKDEV_MODE_PERIODIC,
TICKDEV_MODE_ONESHOT,
};
struct tick_device {
struct clock_event_device *evtdev;
enum tick_device_mode mode;
};
enum tick_nohz_mode {
NOHZ_MODE_INACTIVE,
NOHZ_MODE_LOWRES,
NOHZ_MODE_HIGHRES,
};
/**
* struct tick_sched - sched tick emulation and no idle tick control/stats
* @sched_timer: hrtimer to schedule the periodic tick in high
* resolution mode
* @last_tick: Store the last tick expiry time when the tick
* timer is modified for nohz sleeps. This is necessary
* to resume the tick timer operation in the timeline
* when the CPU returns from nohz sleep.
* @tick_stopped: Indicator that the idle tick has been stopped
* @idle_jiffies: jiffies at the entry to idle for idle time accounting
* @idle_calls: Total number of idle calls
* @idle_sleeps: Number of idle calls, where the sched tick was stopped
* @idle_entrytime: Time when the idle call was entered
* @idle_waketime: Time when the idle was interrupted
* @idle_exittime: Time when the idle state was left
* @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
* @iowait_sleeptime: Sum of the time slept in idle with sched tick stopped, with IO outstanding
* @sleep_length: Duration of the current idle sleep
* @do_timer_lst: CPU was the last one doing do_timer before going idle
*/
struct tick_sched {
struct hrtimer sched_timer;
unsigned long check_clocks;
enum tick_nohz_mode nohz_mode;
ktime_t last_tick;
int inidle;
int tick_stopped;
unsigned long idle_jiffies;
unsigned long idle_calls;
unsigned long idle_sleeps;
int idle_active;
ktime_t idle_entrytime;
ktime_t idle_waketime;
ktime_t idle_exittime;
ktime_t idle_sleeptime;
ktime_t iowait_sleeptime;
ktime_t sleep_length;
unsigned long last_jiffies;
unsigned long next_jiffies;
ktime_t idle_expires;
int do_timer_last;
};
extern void __init tick_init(void);
extern int tick_is_oneshot_available(void);
extern struct tick_device *tick_get_device(int cpu);
# ifdef CONFIG_HIGH_RES_TIMERS
extern int tick_init_highres(void);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_setup_sched_timer(void);
# endif
# if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
extern void tick_cancel_sched_timer(int cpu);
# else
static inline void tick_cancel_sched_timer(int cpu) { }
# endif
# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern struct tick_device *tick_get_broadcast_device(void);
extern struct cpumask *tick_get_broadcast_mask(void);
# ifdef CONFIG_TICK_ONESHOT
extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
# endif
# endif /* BROADCAST */
# ifdef CONFIG_TICK_ONESHOT
extern void tick_clock_notify(void);
extern int tick_check_oneshot_change(int allow_nohz);
extern struct tick_sched *tick_get_tick_sched(int cpu);
extern void tick_irq_enter(void);
extern int tick_oneshot_mode_active(void);
# ifndef arch_needs_cpu
# define arch_needs_cpu(cpu) (0)
# endif
# else
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
static inline void tick_irq_enter(void) { }
static inline int tick_oneshot_mode_active(void) { return 0; }
# endif
#else /* CONFIG_GENERIC_CLOCKEVENTS */
static inline void tick_init(void) { }
static inline void tick_cancel_sched_timer(int cpu) { }
static inline void tick_clock_notify(void) { }
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
static inline void tick_irq_enter(void) { }
static inline int tick_oneshot_mode_active(void) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
# ifdef CONFIG_NO_HZ_COMMON
DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
static inline int tick_nohz_tick_stopped(void)
{
return __this_cpu_read(tick_cpu_sched.tick_stopped);
}
extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern ktime_t tick_nohz_get_sleep_length(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
# else /* !CONFIG_NO_HZ_COMMON */
static inline int tick_nohz_tick_stopped(void)
{
return 0;
}
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
static inline ktime_t tick_nohz_get_sleep_length(void)
{
ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
return len;
}
static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
# endif /* !CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
extern bool tick_nohz_full_running;
extern cpumask_var_t tick_nohz_full_mask;
extern cpumask_var_t housekeeping_mask;
static inline bool tick_nohz_full_enabled(void)
{
if (!context_tracking_is_enabled())
return false;
return tick_nohz_full_running;
}
static inline bool tick_nohz_full_cpu(int cpu)
{
if (!tick_nohz_full_enabled())
return false;
return cpumask_test_cpu(cpu, tick_nohz_full_mask);
}
extern void __tick_nohz_full_check(void);
extern void tick_nohz_full_kick(void);
extern void tick_nohz_full_kick_cpu(int cpu);
extern void tick_nohz_full_kick_all(void);
extern void __tick_nohz_task_switch(struct task_struct *tsk);
#else
static inline bool tick_nohz_full_enabled(void) { return false; }
static inline bool tick_nohz_full_cpu(int cpu) { return false; }
static inline void __tick_nohz_full_check(void) { }
static inline void tick_nohz_full_kick_cpu(int cpu) { }
static inline void tick_nohz_full_kick(void) { }
static inline void tick_nohz_full_kick_all(void) { }
static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
#endif
static inline bool is_housekeeping_cpu(int cpu)
{
#ifdef CONFIG_NO_HZ_FULL
if (tick_nohz_full_enabled())
return cpumask_test_cpu(cpu, housekeeping_mask);
#endif
return true;
}
static inline void housekeeping_affine(struct task_struct *t)
{
#ifdef CONFIG_NO_HZ_FULL
if (tick_nohz_full_enabled())
set_cpus_allowed_ptr(t, housekeeping_mask);
#endif
}
static inline void tick_nohz_full_check(void)
{
if (tick_nohz_full_enabled())
__tick_nohz_full_check();
}
static inline void tick_nohz_task_switch(struct task_struct *tsk)
{
if (tick_nohz_full_enabled())
__tick_nohz_task_switch(tsk);
}
#endif
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