xref: /openbmc/linux/kernel/time/tick-sched.h (revision 9a29f5fc)
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  * @sched_timer:	hrtimer to schedule the periodic tick in high
26  *			resolution mode
27  * @check_clocks:	Notification mechanism about clocksource changes
28  * @nohz_mode:		Mode - one state of tick_nohz_mode
29  * @inidle:		Indicator that the CPU is in the tick idle mode
30  * @tick_stopped:	Indicator that the idle tick has been stopped
31  * @idle_active:	Indicator that the CPU is actively in the tick idle mode;
32  *			it is reset during irq handling phases.
33  * @do_timer_lst:	CPU was the last one doing do_timer before going idle
34  * @got_idle_tick:	Tick timer function has run with @inidle set
35  * @last_tick:		Store the last tick expiry time when the tick
36  *			timer is modified for nohz sleeps. This is necessary
37  *			to resume the tick timer operation in the timeline
38  *			when the CPU returns from nohz sleep.
39  * @next_tick:		Next tick to be fired when in dynticks mode.
40  * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
41  * @idle_calls:		Total number of idle calls
42  * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
43  * @idle_entrytime:	Time when the idle call was entered
44  * @idle_waketime:	Time when the idle was interrupted
45  * @idle_exittime:	Time when the idle state was left
46  * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped
47  * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding
48  * @timer_expires:	Anticipated timer expiration time (in case sched tick is stopped)
49  * @timer_expires_base:	Base time clock monotonic for @timer_expires
50  * @next_timer:		Expiry time of next expiring timer for debugging purpose only
51  * @tick_dep_mask:	Tick dependency mask - is set, if someone needs the tick
52  * @last_tick_jiffies:	Value of jiffies seen on last tick
53  * @stalled_jiffies:	Number of stalled jiffies detected across ticks
54  */
55 struct tick_sched {
56 	struct hrtimer			sched_timer;
57 	unsigned long			check_clocks;
58 	enum tick_nohz_mode		nohz_mode;
59 
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 	ktime_t				last_tick;
67 	ktime_t				next_tick;
68 	unsigned long			idle_jiffies;
69 	unsigned long			idle_calls;
70 	unsigned long			idle_sleeps;
71 	ktime_t				idle_entrytime;
72 	ktime_t				idle_waketime;
73 	ktime_t				idle_exittime;
74 	ktime_t				idle_sleeptime;
75 	ktime_t				iowait_sleeptime;
76 	unsigned long			last_jiffies;
77 	u64				timer_expires;
78 	u64				timer_expires_base;
79 	u64				next_timer;
80 	ktime_t				idle_expires;
81 	atomic_t			tick_dep_mask;
82 	unsigned long			last_tick_jiffies;
83 	unsigned int			stalled_jiffies;
84 };
85 
86 extern struct tick_sched *tick_get_tick_sched(int cpu);
87 
88 extern void tick_setup_sched_timer(void);
89 #if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
90 extern void tick_cancel_sched_timer(int cpu);
91 #else
92 static inline void tick_cancel_sched_timer(int cpu) { }
93 #endif
94 
95 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
96 extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
97 #else
98 static inline int
99 __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
100 {
101 	return -EBUSY;
102 }
103 #endif
104 
105 #endif
106