Merge pull request #47052 from gyliu513/godoc

plugin/pkg/scheduler/algorithm/predicates/predicates.go

@@ -564,6 +564,9 @@ func podName(pod *v1.Pod) string {
 	return pod.Namespace + "/" + pod.Name
 }
 
+// PodFitsResources checks if a node has sufficient resources, such as cpu, memory, gpu, opaque int resources etc to run a pod.
+// First return value indicates whether a node has sufficient resources to run a pod while the second return value indicates the
+// predicate failure reasons if the node has insufficient resources to run the pod.
 func PodFitsResources(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	node := nodeInfo.Node()
 	if node == nil {
@@ -693,6 +696,7 @@ func podMatchesNodeLabels(pod *v1.Pod, node *v1.Node) bool {
 	return nodeAffinityMatches
 }
 
+// PodMatchNodeSelector checks if a pod node selector matches the node label.
 func PodMatchNodeSelector(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	node := nodeInfo.Node()
 	if node == nil {
@@ -704,6 +708,7 @@ func PodMatchNodeSelector(pod *v1.Pod, meta interface{}, nodeInfo *schedulercach
 	return false, []algorithm.PredicateFailureReason{ErrNodeSelectorNotMatch}, nil
 }
 
+// PodFitsHost checks if a pod spec node name matches the current node.
 func PodFitsHost(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	if len(pod.Spec.NodeName) == 0 {
 		return true, nil, nil
@@ -864,6 +869,7 @@ func (s *ServiceAffinity) checkServiceAffinity(pod *v1.Pod, meta interface{}, no
 	return false, []algorithm.PredicateFailureReason{ErrServiceAffinityViolated}, nil
 }
 
+// PodFitsHostPorts checks if a node has free ports for the requested pod ports.
 func PodFitsHostPorts(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	var wantPorts map[int]bool
 	if predicateMeta, ok := meta.(*predicateMetadata); ok {
@@ -897,6 +903,8 @@ func haveSame(a1, a2 []string) bool {
 	return false
 }
 
+// GeneralPredicates checks whether noncriticalPredicates and EssentialPredicates pass. noncriticalPredicates are the predicates
+// that only non-critical pods need and EssentialPredicates are the predicates that all pods, including critical pods, need
 func GeneralPredicates(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	var predicateFails []algorithm.PredicateFailureReason
 	fit, reasons, err := noncriticalPredicates(pod, meta, nodeInfo)
@@ -976,6 +984,9 @@ func NewPodAffinityPredicate(info NodeInfo, podLister algorithm.PodLister) algor
 	return checker.InterPodAffinityMatches
 }
 
+// InterPodAffinityMatches checks if a pod can be scheduled on the specified node with pod affinity/anti-affinity configuration.
+// First return value indicates whether a pod can be scheduled on the specified node while the second return value indicates the
+// predicate failure reasons if the pod cannot be scheduled on the specified node.
 func (c *PodAffinityChecker) InterPodAffinityMatches(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	node := nodeInfo.Node()
 	if node == nil {
@@ -1234,6 +1245,7 @@ func (c *PodAffinityChecker) satisfiesPodsAffinityAntiAffinity(pod *v1.Pod, node
 	return true
 }
 
+// PodToleratesNodeTaints checks if a pod tolertaions can tolerate the node taints
 func PodToleratesNodeTaints(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	taints, err := nodeInfo.Taints()
 	if err != nil {