1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _TICK_SCHED_H
3#define _TICK_SCHED_H
4
5#include <linux/hrtimer.h>
6
7enum tick_device_mode {
8 TICKDEV_MODE_PERIODIC,
9 TICKDEV_MODE_ONESHOT,
10};
11
12struct tick_device {
13 struct clock_event_device *evtdev;
14 enum tick_device_mode mode;
15};
16
17enum tick_nohz_mode {
18 NOHZ_MODE_INACTIVE,
19 NOHZ_MODE_LOWRES,
20 NOHZ_MODE_HIGHRES,
21};
22
23/**
24 * struct tick_sched - sched tick emulation and no idle tick control/stats
25 *
26 * @inidle: Indicator that the CPU is in the tick idle mode
27 * @tick_stopped: Indicator that the idle tick has been stopped
28 * @idle_active: Indicator that the CPU is actively in the tick idle mode;
29 * it is reset during irq handling phases.
30 * @do_timer_last: CPU was the last one doing do_timer before going idle
31 * @got_idle_tick: Tick timer function has run with @inidle set
32 * @stalled_jiffies: Number of stalled jiffies detected across ticks
33 * @last_tick_jiffies: Value of jiffies seen on last tick
34 * @sched_timer: hrtimer to schedule the periodic tick in high
35 * resolution mode
36 * @last_tick: Store the last tick expiry time when the tick
37 * timer is modified for nohz sleeps. This is necessary
38 * to resume the tick timer operation in the timeline
39 * when the CPU returns from nohz sleep.
40 * @next_tick: Next tick to be fired when in dynticks mode.
41 * @idle_jiffies: jiffies at the entry to idle for idle time accounting
42 * @idle_waketime: Time when the idle was interrupted
43 * @idle_entrytime: Time when the idle call was entered
44 * @nohz_mode: Mode - one state of tick_nohz_mode
45 * @last_jiffies: Base jiffies snapshot when next event was last computed
46 * @timer_expires_base: Base time clock monotonic for @timer_expires
47 * @timer_expires: Anticipated timer expiration time (in case sched tick is stopped)
48 * @next_timer: Expiry time of next expiring timer for debugging purpose only
49 * @idle_expires: Next tick in idle, for debugging purpose only
50 * @idle_calls: Total number of idle calls
51 * @idle_sleeps: Number of idle calls, where the sched tick was stopped
52 * @idle_exittime: Time when the idle state was left
53 * @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
54 * @iowait_sleeptime: Sum of the time slept in idle with sched tick stopped, with IO outstanding
55 * @tick_dep_mask: Tick dependency mask - is set, if someone needs the tick
56 * @check_clocks: Notification mechanism about clocksource changes
57 */
58struct tick_sched {
59 /* Common flags */
60 unsigned int inidle : 1;
61 unsigned int tick_stopped : 1;
62 unsigned int idle_active : 1;
63 unsigned int do_timer_last : 1;
64 unsigned int got_idle_tick : 1;
65
66 /* Tick handling: jiffies stall check */
67 unsigned int stalled_jiffies;
68 unsigned long last_tick_jiffies;
69
70 /* Tick handling */
71 struct hrtimer sched_timer;
72 ktime_t last_tick;
73 ktime_t next_tick;
74 unsigned long idle_jiffies;
75 ktime_t idle_waketime;
76
77 /* Idle entry */
78 seqcount_t idle_sleeptime_seq;
79 ktime_t idle_entrytime;
80
81 /* Tick stop */
82 enum tick_nohz_mode nohz_mode;
83 unsigned long last_jiffies;
84 u64 timer_expires_base;
85 u64 timer_expires;
86 u64 next_timer;
87 ktime_t idle_expires;
88 unsigned long idle_calls;
89 unsigned long idle_sleeps;
90
91 /* Idle exit */
92 ktime_t idle_exittime;
93 ktime_t idle_sleeptime;
94 ktime_t iowait_sleeptime;
95
96 /* Full dynticks handling */
97 atomic_t tick_dep_mask;
98
99 /* Clocksource changes */
100 unsigned long check_clocks;
101};
102
103extern struct tick_sched *tick_get_tick_sched(int cpu);
104
105extern void tick_setup_sched_timer(void);
106#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
107extern void tick_cancel_sched_timer(int cpu);
108#else
109static inline void tick_cancel_sched_timer(int cpu) { }
110#endif
111
112#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
113extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
114#else
115static inline int
116__tick_broadcast_oneshot_control(enum tick_broadcast_state state)
117{
118 return -EBUSY;
119}
120#endif
121
122#endif
123

source code of linux/kernel/time/tick-sched.h