1/* SPDX-License-Identifier: GPL-2.0 */
  2
  3#ifdef CONFIG_SCHEDSTATS
  4
  5/*
  6 * Expects runqueue lock to be held for atomicity of update
  7 */
  8static inline void
  9rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
 10{
 11	if (rq) {
 12		rq->rq_sched_info.run_delay += delta;
 13		rq->rq_sched_info.pcount++;
 14	}
 15}
 16
 17/*
 18 * Expects runqueue lock to be held for atomicity of update
 19 */
 20static inline void
 21rq_sched_info_depart(struct rq *rq, unsigned long long delta)
 22{
 23	if (rq)
 24		rq->rq_cpu_time += delta;
 25}
 26
 27static inline void
 28rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
 29{
 30	if (rq)
 31		rq->rq_sched_info.run_delay += delta;
 32}
 33#define   schedstat_enabled()		static_branch_unlikely(&sched_schedstats)
 34#define __schedstat_inc(var)		do { var++; } while (0)
 35#define   schedstat_inc(var)		do { if (schedstat_enabled()) { var++; } } while (0)
 36#define __schedstat_add(var, amt)	do { var += (amt); } while (0)
 37#define   schedstat_add(var, amt)	do { if (schedstat_enabled()) { var += (amt); } } while (0)
 38#define __schedstat_set(var, val)	do { var = (val); } while (0)
 39#define   schedstat_set(var, val)	do { if (schedstat_enabled()) { var = (val); } } while (0)
 40#define   schedstat_val(var)		(var)
 41#define   schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)
 42
 43#else /* !CONFIG_SCHEDSTATS: */
 44static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
 45static inline void rq_sched_info_dequeued(struct rq *rq, unsigned long long delta) { }
 46static inline void rq_sched_info_depart  (struct rq *rq, unsigned long long delta) { }
 47# define   schedstat_enabled()		0
 48# define __schedstat_inc(var)		do { } while (0)
 49# define   schedstat_inc(var)		do { } while (0)
 50# define __schedstat_add(var, amt)	do { } while (0)
 51# define   schedstat_add(var, amt)	do { } while (0)
 52# define __schedstat_set(var, val)	do { } while (0)
 53# define   schedstat_set(var, val)	do { } while (0)
 54# define   schedstat_val(var)		0
 55# define   schedstat_val_or_zero(var)	0
 56#endif /* CONFIG_SCHEDSTATS */
 57
 58#ifdef CONFIG_SCHED_INFO
 59static inline void sched_info_reset_dequeued(struct task_struct *t)
 60{
 61	t->sched_info.last_queued = 0;
 62}
 63
 64/*
 65 * We are interested in knowing how long it was from the *first* time a
 66 * task was queued to the time that it finally hit a CPU, we call this routine
 67 * from dequeue_task() to account for possible rq->clock skew across CPUs. The
 68 * delta taken on each CPU would annul the skew.
 69 */
 70static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
 71{
 72	unsigned long long now = rq_clock(rq), delta = 0;
 73
 74	if (unlikely(sched_info_on()))
 75		if (t->sched_info.last_queued)
 76			delta = now - t->sched_info.last_queued;
 77	sched_info_reset_dequeued(t);
 78	t->sched_info.run_delay += delta;
 79
 80	rq_sched_info_dequeued(rq, delta);
 81}
 82
 83/*
 84 * Called when a task finally hits the CPU.  We can now calculate how
 85 * long it was waiting to run.  We also note when it began so that we
 86 * can keep stats on how long its timeslice is.
 87 */
 88static void sched_info_arrive(struct rq *rq, struct task_struct *t)
 89{
 90	unsigned long long now = rq_clock(rq), delta = 0;
 91
 92	if (t->sched_info.last_queued)
 93		delta = now - t->sched_info.last_queued;
 94	sched_info_reset_dequeued(t);
 95	t->sched_info.run_delay += delta;
 96	t->sched_info.last_arrival = now;
 97	t->sched_info.pcount++;
 98
 99	rq_sched_info_arrive(rq, delta);
100}
101
102/*
103 * This function is only called from enqueue_task(), but also only updates
104 * the timestamp if it is already not set.  It's assumed that
105 * sched_info_dequeued() will clear that stamp when appropriate.
106 */
107static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
108{
109	if (unlikely(sched_info_on())) {
110		if (!t->sched_info.last_queued)
111			t->sched_info.last_queued = rq_clock(rq);
112	}
113}
114
115/*
116 * Called when a process ceases being the active-running process involuntarily
117 * due, typically, to expiring its time slice (this may also be called when
118 * switching to the idle task).  Now we can calculate how long we ran.
119 * Also, if the process is still in the TASK_RUNNING state, call
120 * sched_info_queued() to mark that it has now again started waiting on
121 * the runqueue.
122 */
123static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
124{
125	unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
126
127	rq_sched_info_depart(rq, delta);
128
129	if (t->state == TASK_RUNNING)
130		sched_info_queued(rq, t);
131}
132
133/*
134 * Called when tasks are switched involuntarily due, typically, to expiring
135 * their time slice.  (This may also be called when switching to or from
136 * the idle task.)  We are only called when prev != next.
137 */
138static inline void
139__sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
140{
141	/*
142	 * prev now departs the CPU.  It's not interesting to record
143	 * stats about how efficient we were at scheduling the idle
144	 * process, however.
145	 */
146	if (prev != rq->idle)
147		sched_info_depart(rq, prev);
148
149	if (next != rq->idle)
150		sched_info_arrive(rq, next);
151}
152
153static inline void
154sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
155{
156	if (unlikely(sched_info_on()))
157		__sched_info_switch(rq, prev, next);
158}
159
160#else /* !CONFIG_SCHED_INFO: */
161# define sched_info_queued(rq, t)	do { } while (0)
162# define sched_info_reset_dequeued(t)	do { } while (0)
163# define sched_info_dequeued(rq, t)	do { } while (0)
164# define sched_info_depart(rq, t)	do { } while (0)
165# define sched_info_arrive(rq, next)	do { } while (0)
166# define sched_info_switch(rq, t, next)	do { } while (0)
167#endif /* CONFIG_SCHED_INFO */