From: Daeyeong Lee <daeyeong.lee@samsung.com>
Date: Mon, 14 May 2018 10:09:11 +0000 (+0900)
Subject: sched: ems: ontime: Don't allow to down-migrate heaviest task.
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=391324a26ed2c155d851adb17ef5fbf159779a59;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

sched: ems: ontime: Don't allow to down-migrate heaviest task.

Change-Id: I0daf9e82d69438155ce80c33a6a4709523462491
Signed-off-by: Daeyeong Lee <daeyeong.lee@samsung.com>
---

diff --git a/kernel/sched/ems/ontime.c b/kernel/sched/ems/ontime.c
index e10fc9e47b2d..5ec29d40b48d 100644
--- a/kernel/sched/ems/ontime.c
+++ b/kernel/sched/ems/ontime.c
@@ -535,9 +535,32 @@ int ontime_can_migration(struct task_struct *p, int dst_cpu)
 		return true;
 	}
 
+	/*
+	 * When runqueue is busy, check whether this task is heaviest.
+	 * If this task is not heaviest in runqueue, allow it to be migrated.
+	 */
 	if (cpu_rq(src_cpu)->nr_running > 1) {
-		trace_ems_ontime_check_migrate(p, dst_cpu, true, "curr is busy");
-		return true;
+		struct task_struct *curr = cpu_curr(src_cpu);
+		struct sched_entity *se = __pick_first_entity(p->se.cfs_rq);
+		int count;
+
+		/* Firstly, compare with curr running task */
+		if (ontime_load_avg(p) < ontime_load_avg(curr)) {
+			trace_ems_ontime_check_migrate(p, dst_cpu, true, "busy runqueue");
+			return true;
+		}
+
+		/* Secondly, compare with tasks in rq */
+		for (count = 0; se && count < TASK_TRACK_COUNT;
+				se = __pick_next_entity(se), count++) {
+			if (entity_is_cfs_rq(se))
+				continue;
+
+			if (ontime_load_avg(p) < ontime_load_avg(task_of(se))) {
+				trace_ems_ontime_check_migrate(p, dst_cpu, true, "busy runqueue");
+				return true;
+			}
+		}
 	}
 
 	trace_ems_ontime_check_migrate(p, dst_cpu, false, "heavy task");