From b2d441d2bb83fd5ab62e38c9d926a48629dabe36 Mon Sep 17 00:00:00 2001
From: Jun Gong <jungong@tencent.com>
Date: Tue, 19 Mar 2019 09:25:51 +0800
Subject: [PATCH] Preempt lowest priority task first

---
 pkg/scheduler/actions/preempt/preempt.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/pkg/scheduler/actions/preempt/preempt.go b/pkg/scheduler/actions/preempt/preempt.go
index c6bb3f29a..78ddb5eda 100644
--- a/pkg/scheduler/actions/preempt/preempt.go
+++ b/pkg/scheduler/actions/preempt/preempt.go
@@ -220,8 +220,15 @@ func preempt(
 			continue
 		}
 
-		// Preempt victims for tasks.
-		for _, preemptee := range victims {
+		victimsQueue := util.NewPriorityQueue(func(l, r interface{}) bool {
+			return !ssn.TaskOrderFn(l, r)
+		})
+		for _, victim := range victims {
+			victimsQueue.Push(victim)
+		}
+		// Preempt victims for tasks, pick lowest priority task first.
+		for !victimsQueue.Empty() {
+			preemptee := victimsQueue.Pop().(*api.TaskInfo)
 			glog.Errorf("Try to preempt Task <%s/%s> for Tasks <%s/%s>",
 				preemptee.Namespace, preemptee.Name, preemptor.Namespace, preemptor.Name)
 			if err := stmt.Evict(preemptee, "preempt"); err != nil {