The new util_est_uclamp is essentially clamp(util_est, min, max) and
follows how util_est operates.

Signed-off-by: Hongyan Xia <hongyan.xia2@arm.com>
---
 include/linux/sched.h |  1 +
 kernel/sched/fair.c   | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 63bcb81b20bb..0160567314ae 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -479,6 +479,7 @@ struct sched_avg {
 	unsigned int			util_avg;
 	int				util_avg_bias;
 	unsigned int			util_est;
+	unsigned int			util_est_uclamp;
 } ____cacheline_aligned;
 
 /*
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 23360c666829..0fa48466e02e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4859,6 +4859,16 @@ static inline unsigned long task_util_uclamp(struct task_struct *p)
 
 	return max(ret, 0L);
 }
+
+static inline unsigned long _task_util_est_uclamp(struct task_struct *p)
+{
+	return READ_ONCE(p->se.avg.util_est_uclamp);
+}
+
+static inline unsigned long task_util_est_uclamp(struct task_struct *p)
+{
+	return max(task_util_uclamp(p), _task_util_est_uclamp(p));
+}
 #else
 static inline long task_util_bias(struct task_struct *p)
 {
@@ -4869,6 +4879,16 @@ static inline unsigned long task_util_uclamp(struct task_struct *p)
 {
 	return task_util(p);
 }
+
+static inline unsigned long _task_util_est_uclamp(struct task_struct *p)
+{
+	return _task_util_est(p);
+}
+
+static inline unsigned long task_util_est_uclamp(struct task_struct *p)
+{
+	return task_util_est(p);
+}
 #endif
 
 static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
@@ -4883,6 +4903,9 @@ static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
 	enqueued  = cfs_rq->avg.util_est;
 	enqueued += _task_util_est(p);
 	WRITE_ONCE(cfs_rq->avg.util_est, enqueued);
+	enqueued  = cfs_rq->avg.util_est_uclamp;
+	enqueued += _task_util_est_uclamp(p);
+	WRITE_ONCE(cfs_rq->avg.util_est_uclamp, enqueued);
 
 	trace_sched_util_est_cfs_tp(cfs_rq);
 }
@@ -4899,6 +4922,9 @@ static inline void util_est_dequeue(struct cfs_rq *cfs_rq,
 	enqueued  = cfs_rq->avg.util_est;
 	enqueued -= min_t(unsigned int, enqueued, _task_util_est(p));
 	WRITE_ONCE(cfs_rq->avg.util_est, enqueued);
+	enqueued  = cfs_rq->avg.util_est_uclamp;
+	enqueued -= min_t(unsigned int, enqueued, _task_util_est_uclamp(p));
+	WRITE_ONCE(cfs_rq->avg.util_est_uclamp, enqueued);
 
 	trace_sched_util_est_cfs_tp(cfs_rq);
 }
@@ -4986,6 +5012,10 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
 	ewma  -= last_ewma_diff;
 	ewma >>= UTIL_EST_WEIGHT_SHIFT;
 done:
+	WRITE_ONCE(p->se.avg.util_est_uclamp,
+		   clamp(ewma,
+			 (unsigned int)uclamp_eff_value(p, UCLAMP_MIN),
+			 (unsigned int)uclamp_eff_value(p, UCLAMP_MAX)));
 	ewma |= UTIL_AVG_UNCHANGED;
 	WRITE_ONCE(p->se.avg.util_est, ewma);
 
-- 
2.34.1