From 9a565d149eaeec6f674a78a34732d8d84bf78c86 Mon Sep 17 00:00:00 2001
From: ndixita <ndixita@google.com>
Date: Wed, 30 Oct 2024 01:24:36 +0000
Subject: [PATCH] QOS changes for Pod Level resources

Kubernetes-commit: 26f11c458620751733250b35d1f60c9ed2a96e57
---
 pkg/util/qos/qos.go | 105 ++++++++++++++++++++++++++++----------------
 1 file changed, 66 insertions(+), 39 deletions(-)

diff --git a/pkg/util/qos/qos.go b/pkg/util/qos/qos.go
index 68b1b9072..1b102a0fe 100644
--- a/pkg/util/qos/qos.go
+++ b/pkg/util/qos/qos.go
@@ -37,6 +37,45 @@ func GetPodQOS(pod *core.Pod) core.PodQOSClass {
 	return ComputePodQOS(pod)
 }
 
+// zeroQuantity represents a resource.Quantity with value "0", used as a baseline
+// for resource comparisons.
+var zeroQuantity = resource.MustParse("0")
+
+// processResourceList adds non-zero quantities for supported QoS compute resources
+// quantities from newList to list.
+func processResourceList(list, newList core.ResourceList) {
+	for name, quantity := range newList {
+		if !isSupportedQoSComputeResource(name) {
+			continue
+		}
+		if quantity.Cmp(zeroQuantity) == 1 {
+			delta := quantity.DeepCopy()
+			if _, exists := list[name]; !exists {
+				list[name] = delta
+			} else {
+				delta.Add(list[name])
+				list[name] = delta
+			}
+		}
+	}
+}
+
+// getQOSResources returns a set of resource names from the provided resource list that:
+// 1. Are supported QoS compute resources
+// 2. Have quantities greater than zero
+func getQOSResources(list core.ResourceList) sets.Set[string] {
+	qosResources := sets.New[string]()
+	for name, quantity := range list {
+		if !isSupportedQoSComputeResource(name) {
+			continue
+		}
+		if quantity.Cmp(zeroQuantity) == 1 {
+			qosResources.Insert(string(name))
+		}
+	}
+	return qosResources
+}
+
 // ComputePodQOS evaluates the list of containers to determine a pod's QoS class. This function is more
 // expensive than GetPodQOS which should be used for pods having a non-empty .Status.QOSClass.
 // A pod is besteffort if none of its containers have specified any requests or limits.
@@ -45,50 +84,38 @@ func GetPodQOS(pod *core.Pod) core.PodQOSClass {
 func ComputePodQOS(pod *core.Pod) core.PodQOSClass {
 	requests := core.ResourceList{}
 	limits := core.ResourceList{}
-	zeroQuantity := resource.MustParse("0")
 	isGuaranteed := true
-	// note, ephemeral containers are not considered for QoS as they cannot define resources
-	allContainers := []core.Container{}
-	allContainers = append(allContainers, pod.Spec.Containers...)
-	allContainers = append(allContainers, pod.Spec.InitContainers...)
-	for _, container := range allContainers {
-		// process requests
-		for name, quantity := range container.Resources.Requests {
-			if !isSupportedQoSComputeResource(name) {
-				continue
-			}
-			if quantity.Cmp(zeroQuantity) == 1 {
-				delta := quantity.DeepCopy()
-				if _, exists := requests[name]; !exists {
-					requests[name] = delta
-				} else {
-					delta.Add(requests[name])
-					requests[name] = delta
-				}
-			}
-		}
-		// process limits
-		qosLimitsFound := sets.NewString()
-		for name, quantity := range container.Resources.Limits {
-			if !isSupportedQoSComputeResource(name) {
-				continue
-			}
-			if quantity.Cmp(zeroQuantity) == 1 {
-				qosLimitsFound.Insert(string(name))
-				delta := quantity.DeepCopy()
-				if _, exists := limits[name]; !exists {
-					limits[name] = delta
-				} else {
-					delta.Add(limits[name])
-					limits[name] = delta
-				}
-			}
+	if pod.Spec.Resources != nil {
+		if pod.Spec.Resources.Requests != nil {
+			// process requests
+			processResourceList(requests, pod.Spec.Resources.Requests)
 		}
 
-		if !qosLimitsFound.HasAll(string(core.ResourceMemory), string(core.ResourceCPU)) {
-			isGuaranteed = false
+		if pod.Spec.Resources.Limits != nil {
+			// process limits
+			processResourceList(limits, pod.Spec.Resources.Limits)
+			qosLimitResources := getQOSResources(pod.Spec.Resources.Limits)
+			if !qosLimitResources.HasAll(string(core.ResourceMemory), string(core.ResourceCPU)) {
+				isGuaranteed = false
+			}
+		}
+	} else {
+		// note, ephemeral containers are not considered for QoS as they cannot define resources
+		allContainers := []core.Container{}
+		allContainers = append(allContainers, pod.Spec.Containers...)
+		allContainers = append(allContainers, pod.Spec.InitContainers...)
+		for _, container := range allContainers {
+			// process requests
+			processResourceList(requests, container.Resources.Requests)
+			// process limits
+			processResourceList(limits, container.Resources.Limits)
+			qosLimitResources := getQOSResources(container.Resources.Limits)
+			if !qosLimitResources.HasAll(string(core.ResourceMemory), string(core.ResourceCPU)) {
+				isGuaranteed = false
+			}
 		}
 	}
+
 	if len(requests) == 0 && len(limits) == 0 {
 		return core.PodQOSBestEffort
 	}