[PATCH v6 08/16] sched: Add task enqueue/dequeue trace points

[Gabriele Monaco]

From: Nam Cao <namcao@xxxxxxxxxxxxx>

Add trace points into enqueue_task() and dequeue_task().

Signed-off-by: Nam Cao <namcao@xxxxxxxxxxxxx>
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Reviewed-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Co-developed-by: Gabriele Monaco <gmonaco@xxxxxxxxxx>
Signed-off-by: Gabriele Monaco <gmonaco@xxxxxxxxxx>
---

Notes:
    V5:
    * Do not fire enqueue tracepoint for delayed enqueues

 include/trace/events/sched.h |  8 ++++++++
 kernel/sched/core.c          | 12 +++++++++++-
 kernel/sched/sched.h         |  2 ++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 7b2645b50e78..5844147ec5fd 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -896,6 +896,14 @@ DECLARE_TRACE(sched_set_need_resched,
 	TP_PROTO(struct task_struct *tsk, int cpu, int tif),
 	TP_ARGS(tsk, cpu, tif));
 
+DECLARE_TRACE(sched_enqueue,
+	TP_PROTO(struct task_struct *tsk, int cpu),
+	TP_ARGS(tsk, cpu));
+
+DECLARE_TRACE(sched_dequeue,
+	TP_PROTO(struct task_struct *tsk, int cpu),
+	TP_ARGS(tsk, cpu));
+
 #endif /* _TRACE_SCHED_H */
 
 /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 759777694c78..4ca79ff58fca 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -122,6 +122,8 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_compute_energy_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_entry_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_exit_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_set_need_resched_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_enqueue_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_dequeue_tp);
 
 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
 DEFINE_PER_CPU(struct rnd_state, sched_rnd_state);
@@ -2094,6 +2096,9 @@ unsigned long get_wchan(struct task_struct *p)
 
 void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
 {
+	if (trace_sched_enqueue_tp_enabled() && !(flags & ENQUEUE_DELAYED))
+		trace_sched_enqueue_tp(p, rq->cpu);
+
 	if (!(flags & ENQUEUE_NOCLOCK))
 		update_rq_clock(rq);
 
@@ -2120,6 +2125,8 @@ void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
  */
 inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
 {
+	int ret;
+
 	if (sched_core_enabled(rq))
 		sched_core_dequeue(rq, p, flags);
 
@@ -2136,7 +2143,10 @@ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
 	 * and mark the task ->sched_delayed.
 	 */
 	uclamp_rq_dec(rq, p);
-	return p->sched_class->dequeue_task(rq, p, flags);
+	ret = p->sched_class->dequeue_task(rq, p, flags);
+	if (trace_sched_dequeue_tp_enabled() && !(flags & DEQUEUE_SLEEP))
+		trace_sched_dequeue_tp(p, rq->cpu);
+	return ret;
 }
 
 void activate_task(struct rq *rq, struct task_struct *p, int flags)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b82fb70a9d54..a83177742603 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2944,6 +2944,8 @@ static inline void sub_nr_running(struct rq *rq, unsigned count)
 
 static inline void __block_task(struct rq *rq, struct task_struct *p)
 {
+	trace_sched_dequeue_tp(p, rq->cpu);
+
 	if (p->sched_contributes_to_load)
 		rq->nr_uninterruptible++;
 
-- 
2.53.0