tick.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Tick related global functions
  4 */
  5#ifndef _LINUX_TICK_H
  6#define _LINUX_TICK_H
  7
  8#include <linux/clockchips.h>
  9#include <linux/irqflags.h>
 10#include <linux/percpu.h>
 11#include <linux/context_tracking_state.h>
 12#include <linux/cpumask.h>
 13#include <linux/sched.h>
 14#include <linux/rcupdate.h>
 15#include <linux/static_key.h>
 16
 17#ifdef CONFIG_GENERIC_CLOCKEVENTS
 18extern void __init tick_init(void);
 19/* Should be core only, but ARM BL switcher requires it */
 20extern void tick_suspend_local(void);
 21/* Should be core only, but XEN resume magic and ARM BL switcher require it */
 22extern void tick_resume_local(void);
 23#else /* CONFIG_GENERIC_CLOCKEVENTS */
 24static inline void tick_init(void) { }
 25static inline void tick_suspend_local(void) { }
 26static inline void tick_resume_local(void) { }
 27#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 28
 29#if defined(CONFIG_GENERIC_CLOCKEVENTS) && defined(CONFIG_HOTPLUG_CPU)
 30extern int tick_cpu_dying(unsigned int cpu);
 31extern void tick_assert_timekeeping_handover(void);
 32#else
 33#define tick_cpu_dying	NULL
 34static inline void tick_assert_timekeeping_handover(void) { }
 35#endif
 36
 37#if defined(CONFIG_GENERIC_CLOCKEVENTS) && defined(CONFIG_SUSPEND)
 38extern void tick_freeze(void);
 39extern void tick_unfreeze(void);
 40#else
 41static inline void tick_freeze(void) { }
 42static inline void tick_unfreeze(void) { }
 43#endif
 44
 45#ifdef CONFIG_TICK_ONESHOT
 46extern void tick_irq_enter(void);
 47#  ifndef arch_needs_cpu
 48#   define arch_needs_cpu() (0)
 49#  endif
 50# else
 51static inline void tick_irq_enter(void) { }
 52#endif
 53
 54#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
 55extern void hotplug_cpu__broadcast_tick_pull(int dead_cpu);
 56#else
 57static inline void hotplug_cpu__broadcast_tick_pull(int dead_cpu) { }
 58#endif
 59
 60enum tick_broadcast_mode {
 61	TICK_BROADCAST_OFF,
 62	TICK_BROADCAST_ON,
 63	TICK_BROADCAST_FORCE,
 64};
 65
 66enum tick_broadcast_state {
 67	TICK_BROADCAST_EXIT,
 68	TICK_BROADCAST_ENTER,
 69};
 70
 71extern struct static_key_false arch_needs_tick_broadcast;
 72
 73#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 74extern void tick_broadcast_control(enum tick_broadcast_mode mode);
 75#else
 76static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { }
 77#endif /* BROADCAST */
 78
 79#ifdef CONFIG_GENERIC_CLOCKEVENTS
 80extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
 81#else
 82static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
 83{
 84	return 0;
 85}
 86#endif
 87
 88static inline void tick_broadcast_enable(void)
 89{
 90	tick_broadcast_control(TICK_BROADCAST_ON);
 91}
 92static inline void tick_broadcast_disable(void)
 93{
 94	tick_broadcast_control(TICK_BROADCAST_OFF);
 95}
 96static inline void tick_broadcast_force(void)
 97{
 98	tick_broadcast_control(TICK_BROADCAST_FORCE);
 99}
100static inline int tick_broadcast_enter(void)
101{
102	return tick_broadcast_oneshot_control(TICK_BROADCAST_ENTER);
103}
104static inline void tick_broadcast_exit(void)
105{
106	tick_broadcast_oneshot_control(TICK_BROADCAST_EXIT);
107}
108
109enum tick_dep_bits {
110	TICK_DEP_BIT_POSIX_TIMER	= 0,
111	TICK_DEP_BIT_PERF_EVENTS	= 1,
112	TICK_DEP_BIT_SCHED		= 2,
113	TICK_DEP_BIT_CLOCK_UNSTABLE	= 3,
114	TICK_DEP_BIT_RCU		= 4,
115	TICK_DEP_BIT_RCU_EXP		= 5
116};
117#define TICK_DEP_BIT_MAX TICK_DEP_BIT_RCU_EXP
118
119#define TICK_DEP_MASK_NONE		0
120#define TICK_DEP_MASK_POSIX_TIMER	(1 << TICK_DEP_BIT_POSIX_TIMER)
121#define TICK_DEP_MASK_PERF_EVENTS	(1 << TICK_DEP_BIT_PERF_EVENTS)
122#define TICK_DEP_MASK_SCHED		(1 << TICK_DEP_BIT_SCHED)
123#define TICK_DEP_MASK_CLOCK_UNSTABLE	(1 << TICK_DEP_BIT_CLOCK_UNSTABLE)
124#define TICK_DEP_MASK_RCU		(1 << TICK_DEP_BIT_RCU)
125#define TICK_DEP_MASK_RCU_EXP		(1 << TICK_DEP_BIT_RCU_EXP)
126
127#ifdef CONFIG_NO_HZ_COMMON
128extern bool tick_nohz_enabled;
129extern bool tick_nohz_tick_stopped(void);
130extern bool tick_nohz_tick_stopped_cpu(int cpu);
131extern void tick_nohz_idle_stop_tick(void);
132extern void tick_nohz_idle_retain_tick(void);
133extern void tick_nohz_idle_restart_tick(void);
134extern void tick_nohz_idle_enter(void);
135extern void tick_nohz_idle_exit(void);
136extern void tick_nohz_irq_exit(void);
137extern bool tick_nohz_idle_got_tick(void);
138extern ktime_t tick_nohz_get_next_hrtimer(void);
139extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next);
140extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu);
141extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
142extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
143#else /* !CONFIG_NO_HZ_COMMON */
144#define tick_nohz_enabled (0)
145static inline int tick_nohz_tick_stopped(void) { return 0; }
146static inline int tick_nohz_tick_stopped_cpu(int cpu) { return 0; }
147static inline void tick_nohz_idle_stop_tick(void) { }
148static inline void tick_nohz_idle_retain_tick(void) { }
149static inline void tick_nohz_idle_restart_tick(void) { }
150static inline void tick_nohz_idle_enter(void) { }
151static inline void tick_nohz_idle_exit(void) { }
152static inline bool tick_nohz_idle_got_tick(void) { return false; }
153static inline ktime_t tick_nohz_get_next_hrtimer(void)
154{
155	/* Next wake up is the tick period, assume it starts now */
156	return ktime_add(ktime_get(), TICK_NSEC);
157}
158static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
159{
160	*delta_next = TICK_NSEC;
161	return *delta_next;
162}
163static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
164static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
165#endif /* !CONFIG_NO_HZ_COMMON */
166
167/*
168 * Mask of CPUs that are nohz_full.
169 *
170 * Users should be guarded by CONFIG_NO_HZ_FULL or a tick_nohz_full_cpu()
171 * check.
172 */
173extern cpumask_var_t tick_nohz_full_mask;
174
175#ifdef CONFIG_NO_HZ_FULL
176extern bool tick_nohz_full_running;
177
178static inline bool tick_nohz_full_enabled(void)
179{
180	if (!context_tracking_enabled())
181		return false;
182
183	return tick_nohz_full_running;
184}
185
186/*
187 * Check if a CPU is part of the nohz_full subset. Arrange for evaluating
188 * the cpu expression (typically smp_processor_id()) _after_ the static
189 * key.
190 */
191#define tick_nohz_full_cpu(_cpu) ({					\
192	bool __ret = false;						\
193	if (tick_nohz_full_enabled())					\
194		__ret = cpumask_test_cpu((_cpu), tick_nohz_full_mask);	\
195	__ret;								\
196})
197
198extern void tick_nohz_dep_set(enum tick_dep_bits bit);
199extern void tick_nohz_dep_clear(enum tick_dep_bits bit);
200extern void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit);
201extern void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit);
202extern void tick_nohz_dep_set_task(struct task_struct *tsk,
203				   enum tick_dep_bits bit);
204extern void tick_nohz_dep_clear_task(struct task_struct *tsk,
205				     enum tick_dep_bits bit);
206extern void tick_nohz_dep_set_signal(struct task_struct *tsk,
207				     enum tick_dep_bits bit);
208extern void tick_nohz_dep_clear_signal(struct signal_struct *signal,
209				       enum tick_dep_bits bit);
210extern bool tick_nohz_cpu_hotpluggable(unsigned int cpu);
211
212/*
213 * The below are tick_nohz_[set,clear]_dep() wrappers that optimize off-cases
214 * on top of static keys.
215 */
216static inline void tick_dep_set(enum tick_dep_bits bit)
217{
218	if (tick_nohz_full_enabled())
219		tick_nohz_dep_set(bit);
220}
221
222static inline void tick_dep_clear(enum tick_dep_bits bit)
223{
224	if (tick_nohz_full_enabled())
225		tick_nohz_dep_clear(bit);
226}
227
228static inline void tick_dep_set_cpu(int cpu, enum tick_dep_bits bit)
229{
230	if (tick_nohz_full_cpu(cpu))
231		tick_nohz_dep_set_cpu(cpu, bit);
232}
233
234static inline void tick_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
235{
236	if (tick_nohz_full_cpu(cpu))
237		tick_nohz_dep_clear_cpu(cpu, bit);
238}
239
240static inline void tick_dep_set_task(struct task_struct *tsk,
241				     enum tick_dep_bits bit)
242{
243	if (tick_nohz_full_enabled())
244		tick_nohz_dep_set_task(tsk, bit);
245}
246
247static inline void tick_dep_clear_task(struct task_struct *tsk,
248				       enum tick_dep_bits bit)
249{
250	if (tick_nohz_full_enabled())
251		tick_nohz_dep_clear_task(tsk, bit);
252}
253
254static inline void tick_dep_init_task(struct task_struct *tsk)
255{
256	atomic_set(&tsk->tick_dep_mask, 0);
257}
258
259static inline void tick_dep_set_signal(struct task_struct *tsk,
260				       enum tick_dep_bits bit)
261{
262	if (tick_nohz_full_enabled())
263		tick_nohz_dep_set_signal(tsk, bit);
264}
265static inline void tick_dep_clear_signal(struct signal_struct *signal,
266					 enum tick_dep_bits bit)
267{
268	if (tick_nohz_full_enabled())
269		tick_nohz_dep_clear_signal(signal, bit);
270}
271
272extern void tick_nohz_full_kick_cpu(int cpu);
273extern void __tick_nohz_task_switch(void);
274extern void __init tick_nohz_full_setup(cpumask_var_t cpumask);
275#else
276static inline bool tick_nohz_full_enabled(void) { return false; }
277static inline bool tick_nohz_full_cpu(int cpu) { return false; }
278
279static inline void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit) { }
280static inline void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit) { }
281static inline bool tick_nohz_cpu_hotpluggable(unsigned int cpu) { return true; }
282
283static inline void tick_dep_set(enum tick_dep_bits bit) { }
284static inline void tick_dep_clear(enum tick_dep_bits bit) { }
285static inline void tick_dep_set_cpu(int cpu, enum tick_dep_bits bit) { }
286static inline void tick_dep_clear_cpu(int cpu, enum tick_dep_bits bit) { }
287static inline void tick_dep_set_task(struct task_struct *tsk,
288				     enum tick_dep_bits bit) { }
289static inline void tick_dep_clear_task(struct task_struct *tsk,
290				       enum tick_dep_bits bit) { }
291static inline void tick_dep_init_task(struct task_struct *tsk) { }
292static inline void tick_dep_set_signal(struct task_struct *tsk,
293				       enum tick_dep_bits bit) { }
294static inline void tick_dep_clear_signal(struct signal_struct *signal,
295					 enum tick_dep_bits bit) { }
296
297static inline void tick_nohz_full_kick_cpu(int cpu) { }
298static inline void __tick_nohz_task_switch(void) { }
299static inline void tick_nohz_full_setup(cpumask_var_t cpumask) { }
300#endif
301
302static inline void tick_nohz_task_switch(void)
303{
304	if (tick_nohz_full_enabled())
305		__tick_nohz_task_switch();
306}
307
308static inline void tick_nohz_user_enter_prepare(void)
309{
310	if (tick_nohz_full_cpu(smp_processor_id()))
311		rcu_nocb_flush_deferred_wakeup();
312}
313
314#endif