projects/linux·blob v3.16 · refs

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1/* linux/include/linux/tick.h
2 *
3 * This file contains the structure definitions for tick related functions
4 *
5 */
6#ifndef _LINUX_TICK_H
7#define _LINUX_TICK_H
8
9#include <linux/clockchips.h>
10#include <linux/irqflags.h>
11#include <linux/percpu.h>
12#include <linux/hrtimer.h>
13#include <linux/context_tracking_state.h>
14#include <linux/cpumask.h>
15
16#ifdef CONFIG_GENERIC_CLOCKEVENTS
17
18enum tick_device_mode {
19 TICKDEV_MODE_PERIODIC,
20 TICKDEV_MODE_ONESHOT,
21};
22
23struct tick_device {
24 struct clock_event_device *evtdev;
25 enum tick_device_mode mode;
26};
27
28enum tick_nohz_mode {
29 NOHZ_MODE_INACTIVE,
30 NOHZ_MODE_LOWRES,
31 NOHZ_MODE_HIGHRES,
32};
33
34/**
35 * struct tick_sched - sched tick emulation and no idle tick control/stats
36 * @sched_timer: hrtimer to schedule the periodic tick in high
37 * resolution mode
38 * @last_tick: Store the last tick expiry time when the tick
39 * timer is modified for nohz sleeps. This is necessary
40 * to resume the tick timer operation in the timeline
41 * when the CPU returns from nohz sleep.
42 * @tick_stopped: Indicator that the idle tick has been stopped
43 * @idle_jiffies: jiffies at the entry to idle for idle time accounting
44 * @idle_calls: Total number of idle calls
45 * @idle_sleeps: Number of idle calls, where the sched tick was stopped
46 * @idle_entrytime: Time when the idle call was entered
47 * @idle_waketime: Time when the idle was interrupted
48 * @idle_exittime: Time when the idle state was left
49 * @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
50 * @iowait_sleeptime: Sum of the time slept in idle with sched tick stopped, with IO outstanding
51 * @sleep_length: Duration of the current idle sleep
52 * @do_timer_lst: CPU was the last one doing do_timer before going idle
53 */
54struct tick_sched {
55 struct hrtimer sched_timer;
56 unsigned long check_clocks;
57 enum tick_nohz_mode nohz_mode;
58 ktime_t last_tick;
59 int inidle;
60 int tick_stopped;
61 unsigned long idle_jiffies;
62 unsigned long idle_calls;
63 unsigned long idle_sleeps;
64 int idle_active;
65 ktime_t idle_entrytime;
66 ktime_t idle_waketime;
67 ktime_t idle_exittime;
68 ktime_t idle_sleeptime;
69 ktime_t iowait_sleeptime;
70 ktime_t sleep_length;
71 unsigned long last_jiffies;
72 unsigned long next_jiffies;
73 ktime_t idle_expires;
74 int do_timer_last;
75};
76
77extern void __init tick_init(void);
78extern int tick_is_oneshot_available(void);
79extern struct tick_device *tick_get_device(int cpu);
80
81# ifdef CONFIG_HIGH_RES_TIMERS
82extern int tick_init_highres(void);
83extern int tick_program_event(ktime_t expires, int force);
84extern void tick_setup_sched_timer(void);
85# endif
86
87# if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
88extern void tick_cancel_sched_timer(int cpu);
89# else
90static inline void tick_cancel_sched_timer(int cpu) { }
91# endif
92
93# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
94extern struct tick_device *tick_get_broadcast_device(void);
95extern struct cpumask *tick_get_broadcast_mask(void);
96
97# ifdef CONFIG_TICK_ONESHOT
98extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
99# endif
100
101# endif /* BROADCAST */
102
103# ifdef CONFIG_TICK_ONESHOT
104extern void tick_clock_notify(void);
105extern int tick_check_oneshot_change(int allow_nohz);
106extern struct tick_sched *tick_get_tick_sched(int cpu);
107extern void tick_irq_enter(void);
108extern int tick_oneshot_mode_active(void);
109# ifndef arch_needs_cpu
110# define arch_needs_cpu(cpu) (0)
111# endif
112# else
113static inline void tick_clock_notify(void) { }
114static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
115static inline void tick_irq_enter(void) { }
116static inline int tick_oneshot_mode_active(void) { return 0; }
117# endif
118
119#else /* CONFIG_GENERIC_CLOCKEVENTS */
120static inline void tick_init(void) { }
121static inline void tick_cancel_sched_timer(int cpu) { }
122static inline void tick_clock_notify(void) { }
123static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
124static inline void tick_irq_enter(void) { }
125static inline int tick_oneshot_mode_active(void) { return 0; }
126#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
127
128# ifdef CONFIG_NO_HZ_COMMON
129DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
130
131static inline int tick_nohz_tick_stopped(void)
132{
133 return __this_cpu_read(tick_cpu_sched.tick_stopped);
134}
135
136extern void tick_nohz_idle_enter(void);
137extern void tick_nohz_idle_exit(void);
138extern void tick_nohz_irq_exit(void);
139extern ktime_t tick_nohz_get_sleep_length(void);
140extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
141extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
142
143# else /* !CONFIG_NO_HZ_COMMON */
144static inline int tick_nohz_tick_stopped(void)
145{
146 return 0;
147}
148
149static inline void tick_nohz_idle_enter(void) { }
150static inline void tick_nohz_idle_exit(void) { }
151
152static inline ktime_t tick_nohz_get_sleep_length(void)
153{
154 ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
155
156 return len;
157}
158static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
159static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
160# endif /* !CONFIG_NO_HZ_COMMON */
161
162#ifdef CONFIG_NO_HZ_FULL
163extern bool tick_nohz_full_running;
164extern cpumask_var_t tick_nohz_full_mask;
165
166static inline bool tick_nohz_full_enabled(void)
167{
168 if (!context_tracking_is_enabled())
169 return false;
170
171 return tick_nohz_full_running;
172}
173
174static inline bool tick_nohz_full_cpu(int cpu)
175{
176 if (!tick_nohz_full_enabled())
177 return false;
178
179 return cpumask_test_cpu(cpu, tick_nohz_full_mask);
180}
181
182extern void tick_nohz_init(void);
183extern void __tick_nohz_full_check(void);
184extern void tick_nohz_full_kick(void);
185extern void tick_nohz_full_kick_all(void);
186extern void __tick_nohz_task_switch(struct task_struct *tsk);
187#else
188static inline void tick_nohz_init(void) { }
189static inline bool tick_nohz_full_enabled(void) { return false; }
190static inline bool tick_nohz_full_cpu(int cpu) { return false; }
191static inline void __tick_nohz_full_check(void) { }
192static inline void tick_nohz_full_kick(void) { }
193static inline void tick_nohz_full_kick_all(void) { }
194static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
195#endif
196
197static inline void tick_nohz_full_check(void)
198{
199 if (tick_nohz_full_enabled())
200 __tick_nohz_full_check();
201}
202
203static inline void tick_nohz_task_switch(struct task_struct *tsk)
204{
205 if (tick_nohz_full_enabled())
206 __tick_nohz_task_switch(tsk);
207}
208
209
210#endif