From d7b355d3f4469bdbe1a838dbe9bad18edb1a1394 Mon Sep 17 00:00:00 2001
From: Zexi Li <zexi.li@icloud.com>
Date: Fri, 20 Oct 2023 20:46:01 +0800
Subject: [PATCH] fix(scheduler): improve scheduler prefer and avoid tags
 strategy (#18372)

---
 pkg/scheduler/core/context.go |  2 +-
 pkg/scheduler/core/types.go   | 41 +++++++++++++++++++++++++++++------
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/pkg/scheduler/core/context.go b/pkg/scheduler/core/context.go
index 42679ec865..85a8e55dc2 100644
--- a/pkg/scheduler/core/context.go
+++ b/pkg/scheduler/core/context.go
@@ -636,7 +636,7 @@ func (u *Unit) setScore(id string, val score.SScore, prefer tristate.TriState) {
 
 	scoreObj.ScoreBucket.SetScore(val, prefer)
 
-	log.V(10).Infof("SetScore: %q -> %s", id, val.String())
+	log.V(10).Infof("SetScore: %q -> %s, prefer: %s", id, val.String(), prefer)
 }
 
 func (u *Unit) SetScore(id string, val score.SScore) {
diff --git a/pkg/scheduler/core/types.go b/pkg/scheduler/core/types.go
index 053077339c..c7b6833bff 100644
--- a/pkg/scheduler/core/types.go
+++ b/pkg/scheduler/core/types.go
@@ -157,15 +157,9 @@ func (h HostPriorityList) Len() int {
 	return len(h)
 }
 
-func (h HostPriorityList) Less(i, j int) bool {
+func (h HostPriorityList) compareNormalScore(i, j int) bool {
 	s1 := h[i].Score.ScoreBucket
 	s2 := h[j].Score.ScoreBucket
-	preferScorei, preferScorej := s1.PreferScore()-s1.AvoidScore(), s2.PreferScore()-s1.AvoidScore()
-
-	if preferScorei != preferScorej {
-		return preferScorei < preferScorej
-	}
-
 	normalScorei, normalScorej := s1.NormalScore(), s2.NormalScore()
 	if normalScorei == normalScorej {
 		return h[i].Host < h[j].Host
@@ -173,6 +167,39 @@ func (h HostPriorityList) Less(i, j int) bool {
 	return normalScorei < normalScorej
 }
 
+func (h HostPriorityList) Less(i, j int) bool {
+	si := h[i].Score.ScoreBucket
+	sj := h[j].Score.ScoreBucket
+
+	if si.PreferScore() > 0 || sj.PreferScore() > 0 {
+		if si.PreferScore() != 0 && sj.PreferScore() != 0 {
+			// both have prefer tags
+			return h.compareNormalScore(i, j)
+		}
+		if si.PreferScore() <= 0 {
+			return true
+		}
+		if sj.PreferScore() <= 0 {
+			return false
+		}
+	}
+
+	if si.AvoidScore() > 0 || sj.AvoidScore() > 0 {
+		if si.AvoidScore() != 0 && sj.AvoidScore() != 0 {
+			// both have avoid tags
+			return h.compareNormalScore(i, j)
+		}
+		if si.AvoidScore() > 0 {
+			return true
+		}
+		if sj.AvoidScore() > 0 {
+			return false
+		}
+	}
+
+	return h.compareNormalScore(i, j)
+}
+
 func (h HostPriorityList) Swap(i, j int) {
 	h[i], h[j] = h[j], h[i]
 }