linux-kernel - [PATCH] sched/pelt: cleanup pelt divider

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Date:   Fri, 12 Jun 2020 17:47:03 +0200
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, linux-kernel@...r.kernel.org
Cc:     Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH] sched/pelt: cleanup pelt divider

Factorize in a single place the calculation of the divider to be used to
to compute *_avg from *_sum value

Suggested-by: Dietmar Eggemann <dietmar.eggemann@....com>
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 kernel/sched/fair.c | 32 ++++++++++++++++++--------------
 kernel/sched/pelt.c |  2 +-
 kernel/sched/pelt.h |  5 +++++
 3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0ed04d2a8959..093224bf513b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3095,7 +3095,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 
 #ifdef CONFIG_SMP
 	do {
-		u32 divider = LOAD_AVG_MAX - 1024 + se->avg.period_contrib;
+		u32 divider = get_pelt_divider(&se->avg);
 
 		se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, divider);
 	} while (0);
@@ -3441,16 +3441,18 @@ static inline void
 update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
 {
 	long delta = gcfs_rq->avg.util_avg - se->avg.util_avg;
-	/*
-	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
-	 * See ___update_load_avg() for details.
-	 */
-	u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
+	u32 divider;
 
 	/* Nothing to update */
 	if (!delta)
 		return;
 
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
 	/* Set new sched_entity's utilization */
 	se->avg.util_avg = gcfs_rq->avg.util_avg;
 	se->avg.util_sum = se->avg.util_avg * divider;
@@ -3464,16 +3466,18 @@ static inline void
 update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
 {
 	long delta = gcfs_rq->avg.runnable_avg - se->avg.runnable_avg;
-	/*
-	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
-	 * See ___update_load_avg() for details.
-	 */
-	u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
+	u32 divider;
 
 	/* Nothing to update */
 	if (!delta)
 		return;
 
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
 	/* Set new sched_entity's runnable */
 	se->avg.runnable_avg = gcfs_rq->avg.runnable_avg;
 	se->avg.runnable_sum = se->avg.runnable_avg * divider;
@@ -3501,7 +3505,7 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq
 	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
 	 * See ___update_load_avg() for details.
 	 */
-	divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
+	divider = get_pelt_divider(&cfs_rq->avg);
 
 	if (runnable_sum >= 0) {
 		/*
@@ -3647,7 +3651,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 
 	if (cfs_rq->removed.nr) {
 		unsigned long r;
-		u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib;
+		u32 divider = get_pelt_divider(&cfs_rq->avg);
 
 		raw_spin_lock(&cfs_rq->removed.lock);
 		swap(cfs_rq->removed.util_avg, removed_util);
@@ -3702,7 +3706,7 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
 	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
 	 * See ___update_load_avg() for details.
 	 */
-	u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
+	u32 divider = get_pelt_divider(&cfs_rq->avg);
 
 	/*
 	 * When we attach the @se to the @cfs_rq, we must align the decay
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index b4b1ff96642f..2b607293b6ba 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -264,7 +264,7 @@ ___update_load_sum(u64 now, struct sched_avg *sa,
 static __always_inline void
 ___update_load_avg(struct sched_avg *sa, unsigned long load)
 {
-	u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib;
+	u32 divider = get_pelt_divider(sa);
 
 	/*
 	 * Step 2: update *_avg.
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
index eb034d9f024d..795e43e02afc 100644
--- a/kernel/sched/pelt.h
+++ b/kernel/sched/pelt.h
@@ -37,6 +37,11 @@ update_irq_load_avg(struct rq *rq, u64 running)
 }
 #endif
 
+static inline u32 get_pelt_divider(struct sched_avg *avg)
+{
+	return LOAD_AVG_MAX - 1024 + avg->period_contrib;
+}
+
 /*
  * When a task is dequeued, its estimated utilization should not be update if
  * its util_avg has not been updated at least once.
-- 
2.17.1