1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _KERNEL_STATS_H
3#define _KERNEL_STATS_H
4
5#ifdef CONFIG_SCHEDSTATS
6
7extern struct static_key_false sched_schedstats;
8
9/*
10 * Expects runqueue lock to be held for atomicity of update
11 */
12static inline void
13rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
14{
15	if (rq) {
16		rq->rq_sched_info.run_delay += delta;
17		rq->rq_sched_info.pcount++;
18	}
19}
20
21/*
22 * Expects runqueue lock to be held for atomicity of update
23 */
24static inline void
25rq_sched_info_depart(struct rq *rq, unsigned long long delta)
26{
27	if (rq)
28		rq->rq_cpu_time += delta;
29}
30
31static inline void
32rq_sched_info_dequeue(struct rq *rq, unsigned long long delta)
33{
34	if (rq)
35		rq->rq_sched_info.run_delay += delta;
36}
37#define   schedstat_enabled()		static_branch_unlikely(&sched_schedstats)
38#define __schedstat_inc(var)		do { var++; } while (0)
39#define   schedstat_inc(var)		do { if (schedstat_enabled()) { var++; } } while (0)
40#define __schedstat_add(var, amt)	do { var += (amt); } while (0)
41#define   schedstat_add(var, amt)	do { if (schedstat_enabled()) { var += (amt); } } while (0)
42#define __schedstat_set(var, val)	do { var = (val); } while (0)
43#define   schedstat_set(var, val)	do { if (schedstat_enabled()) { var = (val); } } while (0)
44#define   schedstat_val(var)		(var)
45#define   schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)
46
47void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
48			       struct sched_statistics *stats);
49
50void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
51			     struct sched_statistics *stats);
52void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
53				    struct sched_statistics *stats);
54
55static inline void
56check_schedstat_required(void)
57{
58	if (schedstat_enabled())
59		return;
60
61	/* Force schedstat enabled if a dependent tracepoint is active */
62	if (trace_sched_stat_wait_enabled()    ||
63	    trace_sched_stat_sleep_enabled()   ||
64	    trace_sched_stat_iowait_enabled()  ||
65	    trace_sched_stat_blocked_enabled() ||
66	    trace_sched_stat_runtime_enabled())
67		printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1\n");
68}
69
70#else /* !CONFIG_SCHEDSTATS: */
71
72static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
73static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { }
74static inline void rq_sched_info_depart  (struct rq *rq, unsigned long long delta) { }
75# define   schedstat_enabled()		0
76# define __schedstat_inc(var)		do { } while (0)
77# define   schedstat_inc(var)		do { } while (0)
78# define __schedstat_add(var, amt)	do { } while (0)
79# define   schedstat_add(var, amt)	do { } while (0)
80# define __schedstat_set(var, val)	do { } while (0)
81# define   schedstat_set(var, val)	do { } while (0)
82# define   schedstat_val(var)		0
83# define   schedstat_val_or_zero(var)	0
84
85# define __update_stats_wait_start(rq, p, stats)       do { } while (0)
86# define __update_stats_wait_end(rq, p, stats)         do { } while (0)
87# define __update_stats_enqueue_sleeper(rq, p, stats)  do { } while (0)
88# define check_schedstat_required()                    do { } while (0)
89
90#endif /* CONFIG_SCHEDSTATS */
91
92#ifdef CONFIG_FAIR_GROUP_SCHED
93struct sched_entity_stats {
94	struct sched_entity     se;
95	struct sched_statistics stats;
96} __no_randomize_layout;
97#endif
98
99static inline struct sched_statistics *
100__schedstats_from_se(struct sched_entity *se)
101{
102#ifdef CONFIG_FAIR_GROUP_SCHED
103	if (!entity_is_task(se))
104		return &container_of(se, struct sched_entity_stats, se)->stats;
105#endif
106	return &task_of(se)->stats;
107}
108
109#ifdef CONFIG_PSI
110void psi_task_change(struct task_struct *task, int clear, int set);
111void psi_task_switch(struct task_struct *prev, struct task_struct *next,
112		     bool sleep);
113void psi_account_irqtime(struct task_struct *task, u32 delta);
114
115/*
116 * PSI tracks state that persists across sleeps, such as iowaits and
117 * memory stalls. As a result, it has to distinguish between sleeps,
118 * where a task's runnable state changes, and requeues, where a task
119 * and its state are being moved between CPUs and runqueues.
120 */
121static inline void psi_enqueue(struct task_struct *p, bool wakeup)
122{
123	int clear = 0, set = TSK_RUNNING;
124
125	if (static_branch_likely(&psi_disabled))
126		return;
127
128	if (p->in_memstall)
129		set |= TSK_MEMSTALL_RUNNING;
130
131	if (!wakeup) {
132		if (p->in_memstall)
133			set |= TSK_MEMSTALL;
134	} else {
135		if (p->in_iowait)
136			clear |= TSK_IOWAIT;
137	}
138
139	psi_task_change(p, clear, set);
140}
141
142static inline void psi_dequeue(struct task_struct *p, bool sleep)
143{
144	if (static_branch_likely(&psi_disabled))
145		return;
146
147	/*
148	 * A voluntary sleep is a dequeue followed by a task switch. To
149	 * avoid walking all ancestors twice, psi_task_switch() handles
150	 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
151	 * Do nothing here.
152	 */
153	if (sleep)
154		return;
155
156	psi_task_change(p, p->psi_flags, 0);
157}
158
159static inline void psi_ttwu_dequeue(struct task_struct *p)
160{
161	if (static_branch_likely(&psi_disabled))
162		return;
163	/*
164	 * Is the task being migrated during a wakeup? Make sure to
165	 * deregister its sleep-persistent psi states from the old
166	 * queue, and let psi_enqueue() know it has to requeue.
167	 */
168	if (unlikely(p->psi_flags)) {
169		struct rq_flags rf;
170		struct rq *rq;
171
172		rq = __task_rq_lock(p, &rf);
173		psi_task_change(p, p->psi_flags, 0);
174		__task_rq_unlock(rq, &rf);
175	}
176}
177
178static inline void psi_sched_switch(struct task_struct *prev,
179				    struct task_struct *next,
180				    bool sleep)
181{
182	if (static_branch_likely(&psi_disabled))
183		return;
184
185	psi_task_switch(prev, next, sleep);
186}
187
188#else /* CONFIG_PSI */
189static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
190static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
191static inline void psi_ttwu_dequeue(struct task_struct *p) {}
192static inline void psi_sched_switch(struct task_struct *prev,
193				    struct task_struct *next,
194				    bool sleep) {}
195static inline void psi_account_irqtime(struct task_struct *task, u32 delta) {}
196#endif /* CONFIG_PSI */
197
198#ifdef CONFIG_SCHED_INFO
199/*
200 * We are interested in knowing how long it was from the *first* time a
201 * task was queued to the time that it finally hit a CPU, we call this routine
202 * from dequeue_task() to account for possible rq->clock skew across CPUs. The
203 * delta taken on each CPU would annul the skew.
204 */
205static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
206{
207	unsigned long long delta = 0;
208
209	if (!t->sched_info.last_queued)
210		return;
211
212	delta = rq_clock(rq) - t->sched_info.last_queued;
213	t->sched_info.last_queued = 0;
214	t->sched_info.run_delay += delta;
215
216	rq_sched_info_dequeue(rq, delta);
217}
218
219/*
220 * Called when a task finally hits the CPU.  We can now calculate how
221 * long it was waiting to run.  We also note when it began so that we
222 * can keep stats on how long its timeslice is.
223 */
224static void sched_info_arrive(struct rq *rq, struct task_struct *t)
225{
226	unsigned long long now, delta = 0;
227
228	if (!t->sched_info.last_queued)
229		return;
230
231	now = rq_clock(rq);
232	delta = now - t->sched_info.last_queued;
233	t->sched_info.last_queued = 0;
234	t->sched_info.run_delay += delta;
235	t->sched_info.last_arrival = now;
236	t->sched_info.pcount++;
237
238	rq_sched_info_arrive(rq, delta);
239}
240
241/*
242 * This function is only called from enqueue_task(), but also only updates
243 * the timestamp if it is already not set.  It's assumed that
244 * sched_info_dequeue() will clear that stamp when appropriate.
245 */
246static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t)
247{
248	if (!t->sched_info.last_queued)
249		t->sched_info.last_queued = rq_clock(rq);
250}
251
252/*
253 * Called when a process ceases being the active-running process involuntarily
254 * due, typically, to expiring its time slice (this may also be called when
255 * switching to the idle task).  Now we can calculate how long we ran.
256 * Also, if the process is still in the TASK_RUNNING state, call
257 * sched_info_enqueue() to mark that it has now again started waiting on
258 * the runqueue.
259 */
260static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
261{
262	unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
263
264	rq_sched_info_depart(rq, delta);
265
266	if (task_is_running(t))
267		sched_info_enqueue(rq, t);
268}
269
270/*
271 * Called when tasks are switched involuntarily due, typically, to expiring
272 * their time slice.  (This may also be called when switching to or from
273 * the idle task.)  We are only called when prev != next.
274 */
275static inline void
276sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
277{
278	/*
279	 * prev now departs the CPU.  It's not interesting to record
280	 * stats about how efficient we were at scheduling the idle
281	 * process, however.
282	 */
283	if (prev != rq->idle)
284		sched_info_depart(rq, prev);
285
286	if (next != rq->idle)
287		sched_info_arrive(rq, next);
288}
289
290#else /* !CONFIG_SCHED_INFO: */
291# define sched_info_enqueue(rq, t)	do { } while (0)
292# define sched_info_dequeue(rq, t)	do { } while (0)
293# define sched_info_switch(rq, t, next)	do { } while (0)
294#endif /* CONFIG_SCHED_INFO */
295
296#endif /* _KERNEL_STATS_H */
297