nrt: filter: add function to find numa-affine resources

We call "NUMA-affine" resources compute resources like
CPU and memory/hugepages which we know they do
expose NUMA affinity.

This is another attempt to factor this logic in a central place.

Signed-off-by: Francesco Romani <[email protected]>

Author: ffromani

pkg/noderesourcetopology/filter.go

@@ -22,7 +22,6 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/klog/v2"
-	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
 	v1qos "k8s.io/kubernetes/pkg/apis/core/v1/helper/qos"
 	kubeletconfig "k8s.io/kubernetes/pkg/kubelet/apis/config"
 	bm "k8s.io/kubernetes/pkg/kubelet/cm/topologymanager/bitmask"
@@ -156,21 +155,9 @@ func resourcesAvailableInAnyNUMANodes(lh logr.Logger, numaNodes NUMANodeList, re
 }
 
 func isResourceSetSuitable(qos v1.PodQOSClass, resource v1.ResourceName, quantity, numaQuantity resource.Quantity) bool {
-	// Check for the following:
-	if qos != v1.PodQOSGuaranteed {
-		// 1. set numa node as possible node if resource is memory or Hugepages
-		if resource == v1.ResourceMemory {
-			return true
-		}
-		if v1helper.IsHugePageResourceName(resource) {
-			return true
-		}
-		// 2. set numa node as possible node if resource is CPU
-		if resource == v1.ResourceCPU {
-			return true
-		}
+	if qos != v1.PodQOSGuaranteed && isNUMAAffineResource(resource) {
+		return true
 	}
-	// 3. otherwise check amount of resources
 	return numaQuantity.Cmp(quantity) >= 0
 }
 

pkg/noderesourcetopology/numaresources.go

@@ -35,3 +35,20 @@ func isHostLevelResource(resource corev1.ResourceName) bool {
 	}
 	return false
 }
+
+func isNUMAAffineResource(resource corev1.ResourceName) bool {
+	// NUMA-affine resources are resources which are required to be bound to NUMA nodes.
+	// A Key example is CPU and memory, which must expose NUMA affinity.
+	if resource == corev1.ResourceCPU {
+		return true
+	}
+	if resource == corev1.ResourceMemory {
+		return true
+	}
+	if v1helper.IsHugePageResourceName(resource) {
+		return true
+	}
+	// Devices are *expected* to expose NUMA Affinity, but they are not *required* to do so.
+	// We can't tell for sure, so we default to "no".
+	return false
+}

pkg/noderesourcetopology/numaresources_test.go

@@ -65,3 +65,47 @@ func TestIsHostLevelResource(t *testing.T) {
 		})
 	}
 }
+
+func TestIsNUMAAffineResource(t *testing.T) {
+	testCases := []struct {
+		resource corev1.ResourceName
+		expected bool
+	}{
+		{
+			resource: corev1.ResourceCPU,
+			expected: true,
+		},
+		{
+			resource: corev1.ResourceMemory,
+			expected: true,
+		},
+		{
+			resource: corev1.ResourceName("hugepages-1Gi"),
+			expected: true,
+		},
+		{
+			resource: corev1.ResourceStorage,
+			expected: false,
+		},
+		{
+			resource: corev1.ResourceEphemeralStorage,
+			expected: false,
+		},
+		{
+			resource: corev1.ResourceName("vendor.io/fastest-nic"),
+			expected: false,
+		},
+		{
+			resource: corev1.ResourceName("awesome.com/gpu-for-ai"),
+			expected: false,
+		},
+	}
+	for _, testCase := range testCases {
+		t.Run(string(testCase.resource), func(t *testing.T) {
+			got := isNUMAAffineResource(testCase.resource)
+			if got != testCase.expected {
+				t.Fatalf("expected %t to equal %t", got, testCase.expected)
+			}
+		})
+	}
+}