Merge pull request kubernetes#52637 from stewart-yu/issue#06

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Modify Schedule function

**What this PR does / why we need it**:
It is obvious that no need to prioritizing when only one node after predicate.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:
@davidopp @timothysc

**Release note**:

```release-note
NONE
```

plugin/pkg/scheduler/core/generic_scheduler.go

@@ -129,6 +129,12 @@ func (g *genericScheduler) Schedule(pod *v1.Pod, nodeLister algorithm.NodeLister
 	}
 
 	trace.Step("Prioritizing")
+
+	// When only one node after predicate, just use it.
+	if len(filteredNodes) == 1 {
+		return filteredNodes[0].Name, nil
+	}
+
 	metaPrioritiesInterface := g.priorityMetaProducer(pod, g.cachedNodeInfoMap)
 	priorityList, err := PrioritizeNodes(pod, g.cachedNodeInfoMap, metaPrioritiesInterface, g.prioritizers, filteredNodes, g.extenders)
 	if err != nil {