[PATCH v2 03/12] sched/core: Decompose update_rq_clock()

[Peter Zijlstra <peterz@infradead.org>]

Adds __update_rq_clock() which lacks the double update warning. Additionally it
will now always set UPDATED, even though it might skip the actual update.
Because when we skip the update, we must be up-to-date by definition.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c |   35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -867,29 +867,32 @@ static void update_rq_clock_task(struct
 	update_rq_clock_pelt(rq, delta);
 }
 
-void update_rq_clock(struct rq *rq)
+static void __update_rq_clock(struct rq *rq)
 {
-	s64 delta;
-	u64 clock;
-
 	lockdep_assert_rq_held(rq);
 
-	if (rq->clock_update_flags & RQCF_ACT_SKIP)
-		return;
-
-	if (sched_feat(WARN_DOUBLE_CLOCK))
-		WARN_ON_ONCE(rq->clock_update_flags & RQCF_UPDATED);
 	rq->clock_update_flags |= RQCF_UPDATED;
 
-	clock = sched_clock_cpu(cpu_of(rq));
-	scx_rq_clock_update(rq, clock);
+	if (!(rq->clock_update_flags & RQCF_ACT_SKIP)) {
+		u64 clock = sched_clock_cpu(cpu_of(rq));
+		s64 delta;
+
+		scx_rq_clock_update(rq, clock);
+
+		delta = clock - rq->clock;
+		if (delta > 0) {
+			rq->clock += delta;
+			update_rq_clock_task(rq, delta);
+		}
+	}
+}
 
-	delta = clock - rq->clock;
-	if (delta < 0)
-		return;
-	rq->clock += delta;
+void update_rq_clock(struct rq *rq)
+{
+	if (sched_feat(WARN_DOUBLE_CLOCK))
+		WARN_ON_ONCE(rq->clock_update_flags & RQCF_UPDATED);
 
-	update_rq_clock_task(rq, delta);
+	__update_rq_clock(rq);
 }
 
 #ifdef CONFIG_SCHED_HRTICK