Update checks in mergeProvidersHints:

- Initialize best Hint to TopologyHint{}
- Update checks.
- Move generic unit test case into policy specific tests and updated
expected outcome to reflect changes.

pkg/kubelet/cm/topologymanager/policy_single_numa_node.go

@@ -18,7 +18,6 @@ package topologymanager
 
 import (
 	"k8s.io/klog"
-	"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager/bitmask"
 	"k8s.io/kubernetes/pkg/kubelet/lifecycle"
 )
 
@@ -122,11 +121,10 @@ func (p *singleNumaNodePolicy) mergeProvidersHints(providersHints []map[string][
 		}
 	}
 
-	// Set the bestHint to return from this function as an any-NUMANode
+	// Set the bestHint to return from this function as {nil false}.
-	// affinity with an unpreferred allocation. This will only be returned if
+	// This will only be returned if no better hint can be found when
-	// no better hint can be found when merging hints from each hint provider.
+	// merging hints from each hint provider.
-	defaultAffinity, _ := bitmask.NewBitMask(p.numaNodes...)
+	bestHint := TopologyHint{}
-	bestHint := TopologyHint{defaultAffinity, false}
 	iterateAllProviderTopologyHints(allResourcesHints, func(permutation []TopologyHint) {
 		mergedHint := mergePermutation(p.numaNodes, permutation)
 		// Only consider mergedHints that result in a NUMANodeAffinity == 1 to
@@ -135,12 +133,19 @@ func (p *singleNumaNodePolicy) mergeProvidersHints(providersHints []map[string][
 			return
 		}
 
-		// If the current defaultHint is the same size as the new mergedHint,
+		// If the current bestHint NUMANodeAffinity is nil, update bestHint
-		// do not update defaultHint
+		// to the current mergedHint.
-		if mergedHint.NUMANodeAffinity.Count() == bestHint.NUMANodeAffinity.Count() {
+		if bestHint.NUMANodeAffinity == nil {
+			bestHint = mergedHint
 			return
 		}
-		// In all other cases, update defaultHint to the current mergedHint
+
+		// Only consider mergedHints that have a narrower NUMANodeAffinity
+		// than the NUMANodeAffinity in the current bestHint.
+		if !mergedHint.NUMANodeAffinity.IsNarrowerThan(bestHint.NUMANodeAffinity) {
+			return
+		}
+		// In all other cases, update bestHint to the current mergedHint
 		bestHint = mergedHint
 	})
 	return bestHint

pkg/kubelet/cm/topologymanager/policy_test.go

@@ -89,35 +89,6 @@ func commonPolicyMergeTestCases(numaNodes []int) []policyMergeTestCase {
 				Preferred:        true,
 			},
 		},
-		{
-			name: "Two providers, 1 hint each, no common mask",
-			hp: []HintProvider{
-				&mockHintProvider{
-					map[string][]TopologyHint{
-						"resource1": {
-							{
-								NUMANodeAffinity: NewTestBitMask(0),
-								Preferred:        true,
-							},
-						},
-					},
-				},
-				&mockHintProvider{
-					map[string][]TopologyHint{
-						"resource2": {
-							{
-								NUMANodeAffinity: NewTestBitMask(1),
-								Preferred:        true,
-							},
-						},
-					},
-				},
-			},
-			expected: TopologyHint{
-				NUMANodeAffinity: NewTestBitMask(numaNodes...),
-				Preferred:        false,
-			},
-		},
 		{
 			name: "Two providers, 1 no hints, 1 single hint preferred 1/2",
 			hp: []HintProvider{
@@ -430,6 +401,35 @@ func (p *bestEffortPolicy) mergeTestCases(numaNodes []int) []policyMergeTestCase
 				Preferred:        false,
 			},
 		},
+		{
+			name: "Two providers, 1 hint each, no common mask",
+			hp: []HintProvider{
+				&mockHintProvider{
+					map[string][]TopologyHint{
+						"resource1": {
+							{
+								NUMANodeAffinity: NewTestBitMask(0),
+								Preferred:        true,
+							},
+						},
+					},
+				},
+				&mockHintProvider{
+					map[string][]TopologyHint{
+						"resource2": {
+							{
+								NUMANodeAffinity: NewTestBitMask(1),
+								Preferred:        true,
+							},
+						},
+					},
+				},
+			},
+			expected: TopologyHint{
+				NUMANodeAffinity: NewTestBitMask(numaNodes...),
+				Preferred:        false,
+			},
+		},
 		{
 			name: "Two providers, 1 hint each, 1 wider mask, both preferred 1/2",
 			hp: []HintProvider{
@@ -733,6 +733,35 @@ func (p *singleNumaNodePolicy) mergeTestCases(numaNodes []int) []policyMergeTest
 				Preferred:        true,
 			},
 		},
+		{
+			name: "Two providers, 1 hint each, no common mask",
+			hp: []HintProvider{
+				&mockHintProvider{
+					map[string][]TopologyHint{
+						"resource1": {
+							{
+								NUMANodeAffinity: NewTestBitMask(0),
+								Preferred:        true,
+							},
+						},
+					},
+				},
+				&mockHintProvider{
+					map[string][]TopologyHint{
+						"resource2": {
+							{
+								NUMANodeAffinity: NewTestBitMask(1),
+								Preferred:        true,
+							},
+						},
+					},
+				},
+			},
+			expected: TopologyHint{
+				NUMANodeAffinity: nil,
+				Preferred:        false,
+			},
+		},
 		{
 			name: "Two providers, 1 hint each, same mask, 1 preferred, 1 not 1/2",
 			hp: []HintProvider{