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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
92static inline struct sched_statistics *
93__schedstats_from_se(struct sched_entity *se)
94{
95#ifdef CONFIG_FAIR_GROUP_SCHED
96 if (!entity_is_task(se))
97 return &container_of(se, struct cfs_tg_state, se)->stats;
98#endif
99 return &task_of(se)->stats;
100}
101
102#ifdef CONFIG_PSI
103void psi_task_change(struct task_struct *task, int clear, int set);
104void psi_task_switch(struct task_struct *prev, struct task_struct *next,
105 bool sleep);
106#ifdef CONFIG_IRQ_TIME_ACCOUNTING
107void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_struct *prev);
108#else /* !CONFIG_IRQ_TIME_ACCOUNTING: */
109static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr,
110 struct task_struct *prev) {}
111#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
112/*
113 * PSI tracks state that persists across sleeps, such as iowaits and
114 * memory stalls. As a result, it has to distinguish between sleeps,
115 * where a task's runnable state changes, and migrations, where a task
116 * and its runnable state are being moved between CPUs and runqueues.
117 *
118 * A notable case is a task whose dequeue is delayed. PSI considers
119 * those sleeping, but because they are still on the runqueue they can
120 * go through migration requeues. In this case, *sleeping* states need
121 * to be transferred.
122 */
123static inline void psi_enqueue(struct task_struct *p, int flags)
124{
125 int clear = 0, set = 0;
126
127 if (static_branch_likely(&psi_disabled))
128 return;
129
130 /* Same runqueue, nothing changed for psi */
131 if (flags & ENQUEUE_RESTORE)
132 return;
133
134 /* psi_sched_switch() will handle the flags */
135 if (task_on_cpu(task_rq(p), p))
136 return;
137
138 if (p->se.sched_delayed) {
139 /* CPU migration of "sleeping" task */
140 WARN_ON_ONCE(!(flags & ENQUEUE_MIGRATED));
141 if (p->in_memstall)
142 set |= TSK_MEMSTALL;
143 if (p->in_iowait)
144 set |= TSK_IOWAIT;
145 } else if (flags & ENQUEUE_MIGRATED) {
146 /* CPU migration of runnable task */
147 set = TSK_RUNNING;
148 if (p->in_memstall)
149 set |= TSK_MEMSTALL | TSK_MEMSTALL_RUNNING;
150 } else {
151 /* Wakeup of new or sleeping task */
152 if (p->in_iowait)
153 clear |= TSK_IOWAIT;
154 set = TSK_RUNNING;
155 if (p->in_memstall)
156 set |= TSK_MEMSTALL_RUNNING;
157 }
158
159 psi_task_change(p, clear, set);
160}
161
162static inline void psi_dequeue(struct task_struct *p, int flags)
163{
164 if (static_branch_likely(&psi_disabled))
165 return;
166
167 /* Same runqueue, nothing changed for psi */
168 if (flags & DEQUEUE_SAVE)
169 return;
170
171 /*
172 * A voluntary sleep is a dequeue followed by a task switch. To
173 * avoid walking all ancestors twice, psi_task_switch() handles
174 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
175 * Do nothing here.
176 *
177 * In the SCHED_PROXY_EXECUTION case we may do sleeping
178 * dequeues that are not followed by a task switch, so check
179 * TSK_ONCPU is set to ensure the task switch is imminent.
180 * Otherwise clear the flags as usual.
181 */
182 if ((flags & DEQUEUE_SLEEP) && (p->psi_flags & TSK_ONCPU))
183 return;
184
185 /*
186 * When migrating a task to another CPU, clear all psi
187 * state. The enqueue callback above will work it out.
188 */
189 psi_task_change(p, p->psi_flags, 0);
190}
191
192static inline void psi_ttwu_dequeue(struct task_struct *p)
193{
194 if (static_branch_likely(&psi_disabled))
195 return;
196 /*
197 * Is the task being migrated during a wakeup? Make sure to
198 * deregister its sleep-persistent psi states from the old
199 * queue, and let psi_enqueue() know it has to requeue.
200 */
201 if (unlikely(p->psi_flags)) {
202 struct rq_flags rf;
203 struct rq *rq;
204
205 rq = __task_rq_lock(p, &rf);
206 psi_task_change(p, p->psi_flags, 0);
207 __task_rq_unlock(rq, p, &rf);
208 }
209}
210
211static inline void psi_sched_switch(struct task_struct *prev,
212 struct task_struct *next,
213 bool sleep)
214{
215 if (static_branch_likely(&psi_disabled))
216 return;
217
218 psi_task_switch(prev, next, sleep);
219}
220
221#else /* !CONFIG_PSI: */
222static inline void psi_enqueue(struct task_struct *p, bool migrate) {}
223static inline void psi_dequeue(struct task_struct *p, bool migrate) {}
224static inline void psi_ttwu_dequeue(struct task_struct *p) {}
225static inline void psi_sched_switch(struct task_struct *prev,
226 struct task_struct *next,
227 bool sleep) {}
228static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr,
229 struct task_struct *prev) {}
230#endif /* !CONFIG_PSI */
231
232#ifdef CONFIG_SCHED_INFO
233/*
234 * We are interested in knowing how long it was from the *first* time a
235 * task was queued to the time that it finally hit a CPU, we call this routine
236 * from dequeue_task() to account for possible rq->clock skew across CPUs. The
237 * delta taken on each CPU would annul the skew.
238 */
239static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
240{
241 unsigned long long delta = 0;
242
243 if (!t->sched_info.last_queued)
244 return;
245
246 delta = rq_clock(rq) - t->sched_info.last_queued;
247 t->sched_info.last_queued = 0;
248 t->sched_info.run_delay += delta;
249 if (delta > t->sched_info.max_run_delay) {
250 t->sched_info.max_run_delay = delta;
251 ktime_get_real_ts64(&t->sched_info.max_run_delay_ts);
252 }
253 if (delta && (!t->sched_info.min_run_delay || delta < t->sched_info.min_run_delay))
254 t->sched_info.min_run_delay = delta;
255 rq_sched_info_dequeue(rq, delta);
256}
257
258/*
259 * Called when a task finally hits the CPU. We can now calculate how
260 * long it was waiting to run. We also note when it began so that we
261 * can keep stats on how long its time-slice is.
262 */
263static void sched_info_arrive(struct rq *rq, struct task_struct *t)
264{
265 unsigned long long now, delta = 0;
266
267 if (!t->sched_info.last_queued)
268 return;
269
270 now = rq_clock(rq);
271 delta = now - t->sched_info.last_queued;
272 t->sched_info.last_queued = 0;
273 t->sched_info.run_delay += delta;
274 t->sched_info.last_arrival = now;
275 t->sched_info.pcount++;
276 if (delta > t->sched_info.max_run_delay) {
277 t->sched_info.max_run_delay = delta;
278 ktime_get_real_ts64(&t->sched_info.max_run_delay_ts);
279 }
280 if (delta && (!t->sched_info.min_run_delay || delta < t->sched_info.min_run_delay))
281 t->sched_info.min_run_delay = delta;
282
283 rq_sched_info_arrive(rq, delta);
284}
285
286/*
287 * This function is only called from enqueue_task(), but also only updates
288 * the timestamp if it is already not set. It's assumed that
289 * sched_info_dequeue() will clear that stamp when appropriate.
290 */
291static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t)
292{
293 if (!t->sched_info.last_queued)
294 t->sched_info.last_queued = rq_clock(rq);
295}
296
297/*
298 * Called when a process ceases being the active-running process involuntarily
299 * due, typically, to expiring its time slice (this may also be called when
300 * switching to the idle task). Now we can calculate how long we ran.
301 * Also, if the process is still in the TASK_RUNNING state, call
302 * sched_info_enqueue() to mark that it has now again started waiting on
303 * the runqueue.
304 */
305static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
306{
307 unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
308
309 rq_sched_info_depart(rq, delta);
310
311 if (task_is_running(t))
312 sched_info_enqueue(rq, t);
313}
314
315/*
316 * Called when tasks are switched involuntarily due, typically, to expiring
317 * their time slice. (This may also be called when switching to or from
318 * the idle task.) We are only called when prev != next.
319 */
320static inline void
321sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
322{
323 /*
324 * prev now departs the CPU. It's not interesting to record
325 * stats about how efficient we were at scheduling the idle
326 * process, however.
327 */
328 if (prev != rq->idle)
329 sched_info_depart(rq, prev);
330
331 if (next != rq->idle)
332 sched_info_arrive(rq, next);
333}
334
335#else /* !CONFIG_SCHED_INFO: */
336# define sched_info_enqueue(rq, t) do { } while (0)
337# define sched_info_dequeue(rq, t) do { } while (0)
338# define sched_info_switch(rq, t, next) do { } while (0)
339#endif /* !CONFIG_SCHED_INFO */
340
341#endif /* _KERNEL_STATS_H */