1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _KERNEL_STATS_H
3 #define _KERNEL_STATS_H
4 
5 #ifdef CONFIG_SCHEDSTATS
6 
7 extern struct static_key_false sched_schedstats;
8 
9 /*
10  * Expects runqueue lock to be held for atomicity of update
11  */
12 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)13 rq_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  */
24 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)25 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
26 {
27 	if (rq)
28 		rq->rq_cpu_time += delta;
29 }
30 
31 static inline void
rq_sched_info_dequeue(struct rq * rq,unsigned long long delta)32 rq_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 
47 void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
48 			       struct sched_statistics *stats);
49 
50 void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
51 			     struct sched_statistics *stats);
52 void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
53 				    struct sched_statistics *stats);
54 
55 static inline void
check_schedstat_required(void)56 check_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 
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)72 static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
rq_sched_info_dequeue(struct rq * rq,unsigned long long delta)73 static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { }
rq_sched_info_depart(struct rq * rq,unsigned long long delta)74 static 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
93 struct sched_entity_stats {
94 	struct sched_entity     se;
95 	struct sched_statistics stats;
96 } __no_randomize_layout;
97 #endif
98 
99 static inline struct sched_statistics *
__schedstats_from_se(struct sched_entity * se)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
110 void psi_task_change(struct task_struct *task, int clear, int set);
111 void psi_task_switch(struct task_struct *prev, struct task_struct *next,
112 		     bool sleep);
113 void 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  */
psi_enqueue(struct task_struct * p,bool wakeup)121 static 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 
psi_dequeue(struct task_struct * p,bool sleep)142 static 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 
psi_ttwu_dequeue(struct task_struct * p)159 static 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 
psi_sched_switch(struct task_struct * prev,struct task_struct * next,bool sleep)178 static 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 */
psi_enqueue(struct task_struct * p,bool wakeup)189 static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
psi_dequeue(struct task_struct * p,bool sleep)190 static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
psi_ttwu_dequeue(struct task_struct * p)191 static inline void psi_ttwu_dequeue(struct task_struct *p) {}
psi_sched_switch(struct task_struct * prev,struct task_struct * next,bool sleep)192 static inline void psi_sched_switch(struct task_struct *prev,
193 				    struct task_struct *next,
194 				    bool sleep) {}
psi_account_irqtime(struct task_struct * task,u32 delta)195 static 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  */
sched_info_dequeue(struct rq * rq,struct task_struct * t)205 static 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  */
sched_info_arrive(struct rq * rq,struct task_struct * t)224 static 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  */
sched_info_enqueue(struct rq * rq,struct task_struct * t)246 static 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  */
sched_info_depart(struct rq * rq,struct task_struct * t)260 static 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  */
275 static inline void
sched_info_switch(struct rq * rq,struct task_struct * prev,struct task_struct * next)276 sched_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