xref: /linux/kernel/time/tick-sched.h (revision 9b61b2069681b60d0d0bedbd0fe3c70123dddb19)
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 /* The CPU is in the tick idle mode */
18 #define TS_FLAG_INIDLE		BIT(0)
19 /* The idle tick has been stopped */
20 #define TS_FLAG_STOPPED		BIT(1)
21 /*
22  * Indicator that the CPU is actively in the tick idle mode;
23  * it is reset during irq handling phases.
24  */
25 #define TS_FLAG_IDLE_ACTIVE	BIT(2)
26 /* CPU was the last one doing do_timer before going idle */
27 #define TS_FLAG_DO_TIMER_LAST	BIT(3)
28 /* NO_HZ is enabled */
29 #define TS_FLAG_NOHZ		BIT(4)
30 /* High resolution tick mode */
31 #define TS_FLAG_HIGHRES		BIT(5)
32 
33 /**
34  * struct tick_sched - sched tick emulation and no idle tick control/stats
35  *
36  * @flags:		State flags gathering the TS_FLAG_* features
37  * @got_idle_tick:	Tick timer function has run with @inidle set
38  * @stalled_jiffies:	Number of stalled jiffies detected across ticks
39  * @last_tick_jiffies:	Value of jiffies seen on last tick
40  * @sched_timer:	hrtimer to schedule the periodic tick in high
41  *			resolution mode
42  * @last_tick:		Store the last tick expiry time when the tick
43  *			timer is modified for nohz sleeps. This is necessary
44  *			to resume the tick timer operation in the timeline
45  *			when the CPU returns from nohz sleep.
46  * @next_tick:		Next tick to be fired when in dynticks mode.
47  * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
48  * @idle_waketime:	Time when the idle was interrupted
49  * @idle_sleeptime_seq:	sequence counter for data consistency
50  * @idle_entrytime:	Time when the idle call was entered
51  * @last_jiffies:	Base jiffies snapshot when next event was last computed
52  * @timer_expires_base:	Base time clock monotonic for @timer_expires
53  * @timer_expires:	Anticipated timer expiration time (in case sched tick is stopped)
54  * @next_timer:		Expiry time of next expiring timer for debugging purpose only
55  * @idle_expires:	Next tick in idle, for debugging purpose only
56  * @idle_calls:		Total number of idle calls
57  * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
58  * @idle_exittime:	Time when the idle state was left
59  * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped
60  * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding
61  * @tick_dep_mask:	Tick dependency mask - is set, if someone needs the tick
62  * @check_clocks:	Notification mechanism about clocksource changes
63  */
64 struct tick_sched {
65 	/* Common flags */
66 	unsigned long			flags;
67 
68 	/* Tick handling: jiffies stall check */
69 	unsigned int			stalled_jiffies;
70 	unsigned long			last_tick_jiffies;
71 
72 	/* Tick handling */
73 	struct hrtimer			sched_timer;
74 	ktime_t				last_tick;
75 	ktime_t				next_tick;
76 	unsigned long			idle_jiffies;
77 	ktime_t				idle_waketime;
78 	unsigned int			got_idle_tick;
79 
80 	/* Idle entry */
81 	seqcount_t			idle_sleeptime_seq;
82 	ktime_t				idle_entrytime;
83 
84 	/* Tick stop */
85 	unsigned long			last_jiffies;
86 	u64				timer_expires_base;
87 	u64				timer_expires;
88 	u64				next_timer;
89 	ktime_t				idle_expires;
90 	unsigned long			idle_calls;
91 	unsigned long			idle_sleeps;
92 
93 	/* Idle exit */
94 	ktime_t				idle_exittime;
95 	ktime_t				idle_sleeptime;
96 	ktime_t				iowait_sleeptime;
97 
98 	/* Full dynticks handling */
99 	atomic_t			tick_dep_mask;
100 
101 	/* Clocksource changes */
102 	unsigned long			check_clocks;
103 };
104 
105 extern struct tick_sched *tick_get_tick_sched(int cpu);
106 
107 extern void tick_setup_sched_timer(bool hrtimer);
108 #if defined CONFIG_TICK_ONESHOT
109 extern void tick_sched_timer_dying(int cpu);
110 #else
tick_sched_timer_dying(int cpu)111 static inline void tick_sched_timer_dying(int cpu) { }
112 #endif
113 
114 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
115 extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
116 #else
117 static inline int
__tick_broadcast_oneshot_control(enum tick_broadcast_state state)118 __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
119 {
120 	return -EBUSY;
121 }
122 #endif
123 
124 #endif
125