Perf optimization: Move away from GetPodQOS, using PodStatus.QOSClass instead

pkg/apis/core/helper/qos/qos.go

@@ -30,6 +30,15 @@ func isSupportedQoSComputeResource(name core.ResourceName) bool {
 	return supportedQoSComputeResources.Has(string(name))
 }
 
+// PodQOSClass returns the QoS class of a pod persisted in the PodStatus.
+// If QOSClass is empty, it returns value of GetPodQOS() which computes pod's QoS class.
+func PodQOSClass(pod *core.Pod) core.PodQOSClass {
+	if pod.Status.QOSClass != "" {
+		return pod.Status.QOSClass
+	}
+	return GetPodQOS(pod)
+}
+
 // GetPodQOS returns the QoS class of a pod.
 // A pod is besteffort if none of its containers have specified any requests or limits.
 // A pod is guaranteed only when requests and limits are specified for all the containers and they are equal.

pkg/apis/core/v1/helper/qos/qos.go

@@ -32,6 +32,15 @@ func isSupportedQoSComputeResource(name v1.ResourceName) bool {
 	return supportedQoSComputeResources.Has(string(name))
 }
 
+// PodQOSClass returns the QoS class of a pod persisted in the PodStatus.
+// If QOSClass is empty, it returns value of GetPodQOS() which computes pod's QoS class.
+func PodQOSClass(pod *v1.Pod) v1.PodQOSClass {
+	if pod.Status.QOSClass != "" {
+		return pod.Status.QOSClass
+	}
+	return GetPodQOS(pod)
+}
+
 // GetPodQOS returns the QoS class of a pod.
 // A pod is besteffort if none of its containers have specified any requests or limits.
 // A pod is guaranteed only when requests and limits are specified for all the containers and they are equal.

pkg/apis/core/validation/validation.go

@@ -4785,19 +4785,8 @@ func ValidatePodUpdate(newPod, oldPod *core.Pod, opts PodValidationOptions) fiel
 		return allErrs
 	}
 
-	//TODO(vinaykul,InPlacePodVerticalScaling): With KEP 2527, we can rely on persistence of PodStatus.QOSClass
+	if qos.PodQOSClass(oldPod) != qos.GetPodQOS(newPod) {
-	// We can use PodStatus.QOSClass instead of GetPodQOS here, in kubelet, and elsewhere, as PodStatus.QOSClass
+		allErrs = append(allErrs, field.Invalid(fldPath, newPod.Status.QOSClass, "Pod QoS is immutable"))
-	// does not change once it is bootstrapped in podCreate. This needs to be addressed before beta as a
-	// separate PR covering all uses of GetPodQOS. With that change, we can drop the below block.
-	// Ref: https://github.com/kubernetes/kubernetes/pull/102884#discussion_r1093790446
-	// Ref: https://github.com/kubernetes/kubernetes/pull/102884/#discussion_r663280487
-	if utilfeature.DefaultFeatureGate.Enabled(features.InPlacePodVerticalScaling) {
-		// reject attempts to change pod qos
-		oldQoS := qos.GetPodQOS(oldPod)
-		newQoS := qos.GetPodQOS(newPod)
-		if newQoS != oldQoS {
-			allErrs = append(allErrs, field.Invalid(fldPath, newQoS, "Pod QoS is immutable"))
-		}
 	}
 
 	// handle updateable fields by munging those fields prior to deep equal comparison.

pkg/kubelet/cm/cpumanager/policy_static.go

@@ -419,7 +419,7 @@ func (p *staticPolicy) allocateCPUs(s state.State, numCPUs int, numaAffinity bit
 }
 
 func (p *staticPolicy) guaranteedCPUs(pod *v1.Pod, container *v1.Container) int {
-	if v1qos.GetPodQOS(pod) != v1.PodQOSGuaranteed {
+	if v1qos.PodQOSClass(pod) != v1.PodQOSGuaranteed {
 		return 0
 	}
 	cpuQuantity := container.Resources.Requests[v1.ResourceCPU]

pkg/kubelet/cm/helpers_linux.go

@@ -165,7 +165,7 @@ func ResourceConfigForPod(pod *v1.Pod, enforceCPULimits bool, cpuPeriod uint64,
 	}
 
 	// determine the qos class
-	qosClass := v1qos.GetPodQOS(pod)
+	qosClass := v1qos.PodQOSClass(pod)
 
 	// build the result
 	result := &ResourceConfig{}

pkg/kubelet/cm/memorymanager/policy_static.go

@@ -93,7 +93,7 @@ func (p *staticPolicy) Start(s state.State) error {
 // Allocate call is idempotent
 func (p *staticPolicy) Allocate(s state.State, pod *v1.Pod, container *v1.Container) error {
 	// allocate the memory only for guaranteed pods
-	if v1qos.GetPodQOS(pod) != v1.PodQOSGuaranteed {
+	if v1qos.PodQOSClass(pod) != v1.PodQOSGuaranteed {
 		return nil
 	}
 
@@ -362,7 +362,7 @@ func getPodRequestedResources(pod *v1.Pod) (map[v1.ResourceName]uint64, error) {
 }
 
 func (p *staticPolicy) GetPodTopologyHints(s state.State, pod *v1.Pod) map[string][]topologymanager.TopologyHint {
-	if v1qos.GetPodQOS(pod) != v1.PodQOSGuaranteed {
+	if v1qos.PodQOSClass(pod) != v1.PodQOSGuaranteed {
 		return nil
 	}
 
@@ -390,7 +390,7 @@ func (p *staticPolicy) GetPodTopologyHints(s state.State, pod *v1.Pod) map[strin
 // and is consulted to achieve NUMA aware resource alignment among this
 // and other resource controllers.
 func (p *staticPolicy) GetTopologyHints(s state.State, pod *v1.Pod, container *v1.Container) map[string][]topologymanager.TopologyHint {
-	if v1qos.GetPodQOS(pod) != v1.PodQOSGuaranteed {
+	if v1qos.PodQOSClass(pod) != v1.PodQOSGuaranteed {
 		return nil
 	}
 

pkg/kubelet/cm/pod_container_manager_linux.go

@@ -99,7 +99,7 @@ func (m *podContainerManagerImpl) EnsureExists(pod *v1.Pod) error {
 
 // GetPodContainerName returns the CgroupName identifier, and its literal cgroupfs form on the host.
 func (m *podContainerManagerImpl) GetPodContainerName(pod *v1.Pod) (CgroupName, string) {
-	podQOS := v1qos.GetPodQOS(pod)
+	podQOS := v1qos.PodQOSClass(pod)
 	// Get the parent QOS container name
 	var parentContainer CgroupName
 	switch podQOS {

pkg/kubelet/cm/qos_container_manager_linux.go

@@ -173,7 +173,7 @@ func (m *qosContainerManagerImpl) setCPUCgroupConfig(configs map[v1.PodQOSClass]
 	reuseReqs := make(v1.ResourceList, 4)
 	for i := range pods {
 		pod := pods[i]
-		qosClass := v1qos.GetPodQOS(pod)
+		qosClass := v1qos.PodQOSClass(pod)
 		if qosClass != v1.PodQOSBurstable {
 			// we only care about the burstable qos tier
 			continue
@@ -207,7 +207,7 @@ func (m *qosContainerManagerImpl) getQoSMemoryRequests() map[v1.PodQOSClass]int6
 	reuseReqs := make(v1.ResourceList, 4)
 	for _, pod := range pods {
 		podMemoryRequest := int64(0)
-		qosClass := v1qos.GetPodQOS(pod)
+		qosClass := v1qos.PodQOSClass(pod)
 		if qosClass == v1.PodQOSBestEffort {
 			// limits are not set for Best Effort pods
 			continue

pkg/kubelet/eviction/eviction_manager.go

@@ -151,7 +151,7 @@ func (m *managerImpl) Admit(attrs *lifecycle.PodAdmitAttributes) lifecycle.PodAd
 	// Conditions other than memory pressure reject all pods
 	nodeOnlyHasMemoryPressureCondition := hasNodeCondition(m.nodeConditions, v1.NodeMemoryPressure) && len(m.nodeConditions) == 1
 	if nodeOnlyHasMemoryPressureCondition {
-		notBestEffort := v1.PodQOSBestEffort != v1qos.GetPodQOS(attrs.Pod)
+		notBestEffort := v1.PodQOSBestEffort != v1qos.PodQOSClass(attrs.Pod)
 		if notBestEffort {
 			return lifecycle.PodAdmitResult{Admit: true}
 		}

pkg/kubelet/kubelet_pods.go

@@ -1839,7 +1839,7 @@ func (kl *Kubelet) convertStatusToAPIStatus(pod *v1.Pod, podStatus *kubecontaine
 	}
 
 	// set status for Pods created on versions of kube older than 1.6
-	apiPodStatus.QOSClass = v1qos.GetPodQOS(pod)
+	apiPodStatus.QOSClass = v1qos.PodQOSClass(pod)
 
 	apiPodStatus.ContainerStatuses = kl.convertToAPIContainerStatuses(
 		pod, podStatus,

pkg/kubelet/preemption/preemption.go

@@ -247,7 +247,7 @@ func (a admissionRequirementList) toString() string {
 func sortPodsByQOS(preemptor *v1.Pod, pods []*v1.Pod) (bestEffort, burstable, guaranteed []*v1.Pod) {
 	for _, pod := range pods {
 		if kubetypes.Preemptable(preemptor, pod) {
-			switch v1qos.GetPodQOS(pod) {
+			switch v1qos.PodQOSClass(pod) {
 			case v1.PodQOSBestEffort:
 				bestEffort = append(bestEffort, pod)
 			case v1.PodQOSBurstable:

pkg/kubelet/qos/policy.go

@@ -46,7 +46,7 @@ func GetContainerOOMScoreAdjust(pod *v1.Pod, container *v1.Container, memoryCapa
 		return guaranteedOOMScoreAdj
 	}
 
-	switch v1qos.GetPodQOS(pod) {
+	switch v1qos.PodQOSClass(pod) {
 	case v1.PodQOSGuaranteed:
 		// Guaranteed containers should be the last to get killed.
 		return guaranteedOOMScoreAdj

pkg/quota/v1/evaluator/core/pods.go

@@ -375,7 +375,7 @@ func PodUsageFunc(obj runtime.Object, clock clock.Clock) (corev1.ResourceList, e
 }
 
 func isBestEffort(pod *corev1.Pod) bool {
-	return qos.GetPodQOS(pod) == corev1.PodQOSBestEffort
+	return qos.PodQOSClass(pod) == corev1.PodQOSBestEffort
 }
 
 func isTerminating(pod *corev1.Pod) bool {

plugin/pkg/admission/podtolerationrestriction/admission.go

@@ -99,7 +99,7 @@ func (p *Plugin) Admit(ctx context.Context, a admission.Attributes, o admission.
 		extraTolerations = ts
 	}
 
-	if qoshelper.GetPodQOS(pod) != api.PodQOSBestEffort {
+	if qoshelper.PodQOSClass(pod) != api.PodQOSBestEffort {
 		extraTolerations = append(extraTolerations, api.Toleration{
 			Key:      corev1.TaintNodeMemoryPressure,
 			Operator: api.TolerationOpExists,

staging/src/k8s.io/kubectl/pkg/describe/describe.go

@@ -871,11 +871,7 @@ func describePod(pod *corev1.Pod, events *corev1.EventList) (string, error) {
 			}
 		}
 		describeVolumes(pod.Spec.Volumes, w, "")
-		if pod.Status.QOSClass != "" {
+		w.Write(LEVEL_0, "QoS Class:\t%s\n", qos.PodQOSClass(pod))
-			w.Write(LEVEL_0, "QoS Class:\t%s\n", pod.Status.QOSClass)
-		} else {
-			w.Write(LEVEL_0, "QoS Class:\t%s\n", qos.GetPodQOS(pod))
-		}
 		printLabelsMultiline(w, "Node-Selectors", pod.Spec.NodeSelector)
 		printPodTolerationsMultiline(w, "Tolerations", pod.Spec.Tolerations)
 		describeTopologySpreadConstraints(pod.Spec.TopologySpreadConstraints, w, "")

staging/src/k8s.io/kubectl/pkg/util/qos/qos.go

@@ -28,6 +28,15 @@ func isSupportedQoSComputeResource(name core.ResourceName) bool {
 	return supportedQoSComputeResources.Has(string(name))
 }
 
+// PodQOSClass returns the QoS class of a pod persisted in the PodStatus.
+// If QOSClass is empty, it returns value of GetPodQOS() which computes pod's QoS class.
+func PodQOSClass(pod *core.Pod) core.PodQOSClass {
+	if pod.Status.QOSClass != "" {
+		return pod.Status.QOSClass
+	}
+	return GetPodQOS(pod)
+}
+
 // GetPodQOS returns the QoS class of a pod.
 // A pod is besteffort if none of its containers have specified any requests or limits.
 // A pod is guaranteed only when requests and limits are specified for all the containers and they are equal.

test/e2e/scheduling/priorities.go

@@ -501,7 +501,7 @@ func computeCPUMemFraction(node v1.Node, resource *v1.ResourceRequirements, pods
 	for _, pod := range pods {
 		framework.Logf("Pod for on the node: %v, Cpu: %v, Mem: %v", pod.Name, getNonZeroRequests(pod).MilliCPU, getNonZeroRequests(pod).Memory)
 		// Ignore best effort pods while computing fractions as they won't be taken in account by scheduler.
-		if v1qos.GetPodQOS(pod) == v1.PodQOSBestEffort {
+		if v1qos.PodQOSClass(pod) == v1.PodQOSBestEffort {
 			continue
 		}
 		totalRequestedCPUResource += getNonZeroRequests(pod).MilliCPU