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1 
2 #ifdef CONFIG_SCHEDSTATS
3 
4 /*
5  * Expects runqueue lock to be held for atomicity of update
6  */
7 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)8 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
9 {
10 	if (rq) {
11 		rq->rq_sched_info.run_delay += delta;
12 		rq->rq_sched_info.pcount++;
13 	}
14 }
15 
16 /*
17  * Expects runqueue lock to be held for atomicity of update
18  */
19 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)20 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
21 {
22 	if (rq)
23 		rq->rq_cpu_time += delta;
24 }
25 
26 static inline void
rq_sched_info_dequeued(struct rq * rq,unsigned long long delta)27 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
28 {
29 	if (rq)
30 		rq->rq_sched_info.run_delay += delta;
31 }
32 # define schedstat_inc(rq, field)	do { (rq)->field++; } while (0)
33 # define schedstat_add(rq, field, amt)	do { (rq)->field += (amt); } while (0)
34 # define schedstat_set(var, val)	do { var = (val); } while (0)
35 #else /* !CONFIG_SCHEDSTATS */
36 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)37 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
38 {}
39 static inline void
rq_sched_info_dequeued(struct rq * rq,unsigned long long delta)40 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
41 {}
42 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)43 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
44 {}
45 # define schedstat_inc(rq, field)	do { } while (0)
46 # define schedstat_add(rq, field, amt)	do { } while (0)
47 # define schedstat_set(var, val)	do { } while (0)
48 #endif
49 
50 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
sched_info_reset_dequeued(struct task_struct * t)51 static inline void sched_info_reset_dequeued(struct task_struct *t)
52 {
53 	t->sched_info.last_queued = 0;
54 }
55 
56 /*
57  * We are interested in knowing how long it was from the *first* time a
58  * task was queued to the time that it finally hit a cpu, we call this routine
59  * from dequeue_task() to account for possible rq->clock skew across cpus. The
60  * delta taken on each cpu would annul the skew.
61  */
sched_info_dequeued(struct rq * rq,struct task_struct * t)62 static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
63 {
64 	unsigned long long now = rq_clock(rq), delta = 0;
65 
66 	if (unlikely(sched_info_on()))
67 		if (t->sched_info.last_queued)
68 			delta = now - t->sched_info.last_queued;
69 	sched_info_reset_dequeued(t);
70 	t->sched_info.run_delay += delta;
71 
72 	rq_sched_info_dequeued(rq, delta);
73 }
74 
75 /*
76  * Called when a task finally hits the cpu.  We can now calculate how
77  * long it was waiting to run.  We also note when it began so that we
78  * can keep stats on how long its timeslice is.
79  */
sched_info_arrive(struct rq * rq,struct task_struct * t)80 static void sched_info_arrive(struct rq *rq, struct task_struct *t)
81 {
82 	unsigned long long now = rq_clock(rq), delta = 0;
83 
84 	if (t->sched_info.last_queued)
85 		delta = now - t->sched_info.last_queued;
86 	sched_info_reset_dequeued(t);
87 	t->sched_info.run_delay += delta;
88 	t->sched_info.last_arrival = now;
89 	t->sched_info.pcount++;
90 
91 	rq_sched_info_arrive(rq, delta);
92 }
93 
94 /*
95  * This function is only called from enqueue_task(), but also only updates
96  * the timestamp if it is already not set.  It's assumed that
97  * sched_info_dequeued() will clear that stamp when appropriate.
98  */
sched_info_queued(struct rq * rq,struct task_struct * t)99 static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
100 {
101 	if (unlikely(sched_info_on()))
102 		if (!t->sched_info.last_queued)
103 			t->sched_info.last_queued = rq_clock(rq);
104 }
105 
106 /*
107  * Called when a process ceases being the active-running process involuntarily
108  * due, typically, to expiring its time slice (this may also be called when
109  * switching to the idle task).  Now we can calculate how long we ran.
110  * Also, if the process is still in the TASK_RUNNING state, call
111  * sched_info_queued() to mark that it has now again started waiting on
112  * the runqueue.
113  */
sched_info_depart(struct rq * rq,struct task_struct * t)114 static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
115 {
116 	unsigned long long delta = rq_clock(rq) -
117 					t->sched_info.last_arrival;
118 
119 	rq_sched_info_depart(rq, delta);
120 
121 	if (t->state == TASK_RUNNING)
122 		sched_info_queued(rq, t);
123 }
124 
125 /*
126  * Called when tasks are switched involuntarily due, typically, to expiring
127  * their time slice.  (This may also be called when switching to or from
128  * the idle task.)  We are only called when prev != next.
129  */
130 static inline void
__sched_info_switch(struct rq * rq,struct task_struct * prev,struct task_struct * next)131 __sched_info_switch(struct rq *rq,
132 		    struct task_struct *prev, struct task_struct *next)
133 {
134 	/*
135 	 * prev now departs the cpu.  It's not interesting to record
136 	 * stats about how efficient we were at scheduling the idle
137 	 * process, however.
138 	 */
139 	if (prev != rq->idle)
140 		sched_info_depart(rq, prev);
141 
142 	if (next != rq->idle)
143 		sched_info_arrive(rq, next);
144 }
145 static inline void
sched_info_switch(struct rq * rq,struct task_struct * prev,struct task_struct * next)146 sched_info_switch(struct rq *rq,
147 		  struct task_struct *prev, struct task_struct *next)
148 {
149 	if (unlikely(sched_info_on()))
150 		__sched_info_switch(rq, prev, next);
151 }
152 #else
153 #define sched_info_queued(rq, t)		do { } while (0)
154 #define sched_info_reset_dequeued(t)	do { } while (0)
155 #define sched_info_dequeued(rq, t)		do { } while (0)
156 #define sched_info_depart(rq, t)		do { } while (0)
157 #define sched_info_arrive(rq, next)		do { } while (0)
158 #define sched_info_switch(rq, t, next)		do { } while (0)
159 #endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
160 
161 /*
162  * The following are functions that support scheduler-internal time accounting.
163  * These functions are generally called at the timer tick.  None of this depends
164  * on CONFIG_SCHEDSTATS.
165  */
166 
167 /**
168  * cputimer_running - return true if cputimer is running
169  *
170  * @tsk:	Pointer to target task.
171  */
cputimer_running(struct task_struct * tsk)172 static inline bool cputimer_running(struct task_struct *tsk)
173 
174 {
175 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
176 
177 	if (!cputimer->running)
178 		return false;
179 
180 	/*
181 	 * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
182 	 * in __exit_signal(), we won't account to the signal struct further
183 	 * cputime consumed by that task, even though the task can still be
184 	 * ticking after __exit_signal().
185 	 *
186 	 * In order to keep a consistent behaviour between thread group cputime
187 	 * and thread group cputimer accounting, lets also ignore the cputime
188 	 * elapsing after __exit_signal() in any thread group timer running.
189 	 *
190 	 * This makes sure that POSIX CPU clocks and timers are synchronized, so
191 	 * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
192 	 * clock delta is behind the expiring timer value.
193 	 */
194 	if (unlikely(!tsk->sighand))
195 		return false;
196 
197 	return true;
198 }
199 
200 /**
201  * account_group_user_time - Maintain utime for a thread group.
202  *
203  * @tsk:	Pointer to task structure.
204  * @cputime:	Time value by which to increment the utime field of the
205  *		thread_group_cputime structure.
206  *
207  * If thread group time is being maintained, get the structure for the
208  * running CPU and update the utime field there.
209  */
account_group_user_time(struct task_struct * tsk,cputime_t cputime)210 static inline void account_group_user_time(struct task_struct *tsk,
211 					   cputime_t cputime)
212 {
213 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
214 
215 	if (!cputimer_running(tsk))
216 		return;
217 
218 	raw_spin_lock(&cputimer->lock);
219 	cputimer->cputime.utime += cputime;
220 	raw_spin_unlock(&cputimer->lock);
221 }
222 
223 /**
224  * account_group_system_time - Maintain stime for a thread group.
225  *
226  * @tsk:	Pointer to task structure.
227  * @cputime:	Time value by which to increment the stime field of the
228  *		thread_group_cputime structure.
229  *
230  * If thread group time is being maintained, get the structure for the
231  * running CPU and update the stime field there.
232  */
account_group_system_time(struct task_struct * tsk,cputime_t cputime)233 static inline void account_group_system_time(struct task_struct *tsk,
234 					     cputime_t cputime)
235 {
236 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
237 
238 	if (!cputimer_running(tsk))
239 		return;
240 
241 	raw_spin_lock(&cputimer->lock);
242 	cputimer->cputime.stime += cputime;
243 	raw_spin_unlock(&cputimer->lock);
244 }
245 
246 /**
247  * account_group_exec_runtime - Maintain exec runtime for a thread group.
248  *
249  * @tsk:	Pointer to task structure.
250  * @ns:		Time value by which to increment the sum_exec_runtime field
251  *		of the thread_group_cputime structure.
252  *
253  * If thread group time is being maintained, get the structure for the
254  * running CPU and update the sum_exec_runtime field there.
255  */
account_group_exec_runtime(struct task_struct * tsk,unsigned long long ns)256 static inline void account_group_exec_runtime(struct task_struct *tsk,
257 					      unsigned long long ns)
258 {
259 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
260 
261 	if (!cputimer_running(tsk))
262 		return;
263 
264 	raw_spin_lock(&cputimer->lock);
265 	cputimer->cputime.sum_exec_runtime += ns;
266 	raw_spin_unlock(&cputimer->lock);
267 }
268