From e40349e6d4fb55ec028600ee1fa54f72b1b85474 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 23 Oct 2020 12:12:15 +0200
Subject: [PATCH 018/327] sched: Add migrate_disable() tracepoints

XXX write a tracer:

 - 'migirate_disable() -> migrate_enable()' time in task_sched_runtime()
 - 'migrate_pull -> sched-in' time in task_sched_runtime()

The first will give worst case for the second, which is the actual
interference experienced by the task to due migration constraints of
migrate_disable().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/trace/events/sched.h | 12 ++++++++++++
 kernel/sched/core.c          |  4 ++++
 kernel/sched/deadline.c      |  1 +
 kernel/sched/rt.c            |  8 +++++++-
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 5039af667645..a5d81cec7f0a 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -734,6 +734,18 @@ DECLARE_TRACE(sched_update_nr_running_tp,
 	TP_PROTO(struct rq *rq, int change),
 	TP_ARGS(rq, change));
 
+DECLARE_TRACE(sched_migrate_disable_tp,
+	      TP_PROTO(struct task_struct *p),
+	      TP_ARGS(p));
+
+DECLARE_TRACE(sched_migrate_enable_tp,
+	      TP_PROTO(struct task_struct *p),
+	      TP_ARGS(p));
+
+DECLARE_TRACE(sched_migrate_pull_tp,
+	      TP_PROTO(struct task_struct *p),
+	      TP_ARGS(p));
+
 #endif /* _TRACE_SCHED_H */
 
 /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7889b6037e61..e731c752ee48 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1741,6 +1741,8 @@ void migrate_disable(void)
 		return;
 	}
 
+	trace_sched_migrate_disable_tp(p);
+
 	preempt_disable();
 	this_rq()->nr_pinned++;
 	p->migration_disabled = 1;
@@ -1773,6 +1775,8 @@ void migrate_enable(void)
 	p->migration_disabled = 0;
 	this_rq()->nr_pinned--;
 	preempt_enable();
+
+	trace_sched_migrate_enable_tp(p);
 }
 EXPORT_SYMBOL_GPL(migrate_enable);
 
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 7cf3248894a9..fcf546cd2eac 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2282,6 +2282,7 @@ static void pull_dl_task(struct rq *this_rq)
 				goto skip;
 
 			if (is_migration_disabled(p)) {
+				trace_sched_migrate_pull_tp(p);
 				push_task = get_push_task(src_rq);
 			} else {
 				deactivate_task(src_rq, p, 0);
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index c916dbc2a016..5dc1ee8dcec2 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1891,7 +1891,12 @@ static int push_rt_task(struct rq *rq, bool pull)
 		struct task_struct *push_task = NULL;
 		int cpu;
 
-		if (!pull || rq->push_busy)
+		if (!pull)
+			return 0;
+
+		trace_sched_migrate_pull_tp(next_task);
+
+		if (rq->push_busy)
 			return 0;
 
 		cpu = find_lowest_rq(rq->curr);
@@ -2237,6 +2242,7 @@ static void pull_rt_task(struct rq *this_rq)
 				goto skip;
 
 			if (is_migration_disabled(p)) {
+				trace_sched_migrate_pull_tp(p);
 				push_task = get_push_task(src_rq);
 			} else {
 				deactivate_task(src_rq, p, 0);
-- 
2.49.0

