1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _TICK_SCHED_H
3 #define _TICK_SCHED_H
4 
5 #include <linux/hrtimer.h>
6 
7 enum tick_device_mode {
8 	TICKDEV_MODE_PERIODIC,
9 	TICKDEV_MODE_ONESHOT,
10 };
11 
12 struct tick_device {
13 	struct clock_event_device *evtdev;
14 	enum tick_device_mode mode;
15 };
16 
17 enum 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  */
58 struct 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 
103 extern struct tick_sched *tick_get_tick_sched(int cpu);
104 
105 extern void tick_setup_sched_timer(void);
106 #if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
107 extern void tick_cancel_sched_timer(int cpu);
108 #else
tick_cancel_sched_timer(int cpu)109 static inline void tick_cancel_sched_timer(int cpu) { }
110 #endif
111 
112 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
113 extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
114 #else
115 static inline int
__tick_broadcast_oneshot_control(enum tick_broadcast_state state)116 __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
117 {
118 	return -EBUSY;
119 }
120 #endif
121 
122 #endif
123