Treat memory-only NUMA nodes as valid topology

lib/utils/sysinfo/sysinfo.go

@@ -223,8 +223,11 @@ func GetNodesInfo(sysFs sysfs.SysFs) ([]info.Node, int, error) {
 		node := info.Node{Id: id}
 
 		cpuDirs, err := sysFs.GetCPUsPaths(nodeDir)
+		if err != nil {
+			return nil, 0, fmt.Errorf("failed to get CPUs for NUMA node %q: %w", nodeDir, err)
+		}
 		if len(cpuDirs) == 0 {
-			klog.Warningf("Found node without any CPU, nodeDir: %s, number of cpuDirs %d, err: %v", nodeDir, len(cpuDirs), err)
+			klog.V(4).Infof("Found memory-only NUMA node, nodeDir: %s", nodeDir)
 		} else {
 			cores, err := getCoresInfo(sysFs, cpuDirs)
 			if err != nil {

lib/utils/sysinfo/sysinfo_test.go

@@ -16,6 +16,7 @@ package sysinfo
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"sort"
@@ -372,6 +373,58 @@ func TestGetNodesInfo(t *testing.T) {
 	}
 }
 
+func TestGetNodesInfoWithMemoryOnlyNode(t *testing.T) {
+	fakeSys := &fakesysfs.FakeSysFs{}
+	nodePath := "/fakeSysfs/devices/system/node/node1"
+	fakeSys.SetNodesPaths([]string{nodePath}, nil)
+	fakeSys.SetCPUsPaths(map[string][]string{nodePath: {}}, nil)
+	fakeSys.SetMemory("MemTotal: 1048576 kB", nil)
+	fakeSys.SetHugePages(nil, nil)
+	fakeSys.SetDistances(nodePath, "10", nil)
+	wantMemory := uint64(1024 * 1024 * 1024)
+
+	nodes, cores, err := GetNodesInfo(fakeSys)
+
+	if err != nil {
+		t.Fatalf("GetNodesInfo() returned unexpected error: %v", err)
+	}
+	if cores != 0 {
+		t.Errorf("GetNodesInfo() cores = %d, want 0", cores)
+	}
+	if len(nodes) != 1 {
+		t.Fatalf("GetNodesInfo() returned %d nodes, want 1", len(nodes))
+	}
+	if nodes[0].Id != 1 {
+		t.Errorf("GetNodesInfo() node ID = %d, want 1", nodes[0].Id)
+	}
+	if len(nodes[0].Cores) != 0 {
+		t.Errorf("GetNodesInfo() memory-only node cores = %v, want none", nodes[0].Cores)
+	}
+	if nodes[0].Memory != wantMemory {
+		t.Errorf("GetNodesInfo() memory = %d, want %d", nodes[0].Memory, wantMemory)
+	}
+}
+
+func TestGetNodesInfoReturnsCPUPathError(t *testing.T) {
+	fakeSys := &fakesysfs.FakeSysFs{}
+	nodePath := "/fakeSysfs/devices/system/node/node0"
+	wantErr := errors.New("cannot read CPU paths")
+	fakeSys.SetNodesPaths([]string{nodePath}, nil)
+	fakeSys.SetCPUsPaths(nil, wantErr)
+
+	nodes, cores, err := GetNodesInfo(fakeSys)
+
+	if !errors.Is(err, wantErr) {
+		t.Errorf("GetNodesInfo() error = %v, want wrapped %v", err, wantErr)
+	}
+	if nodes != nil {
+		t.Errorf("GetNodesInfo() nodes on error = %v, want nil", nodes)
+	}
+	if cores != 0 {
+		t.Errorf("GetNodesInfo() cores on error = %d, want 0", cores)
+	}
+}
+
 func TestGetNodesInfoWithOfflineCPUs(t *testing.T) {
 	fakeSys := &fakesysfs.FakeSysFs{}
 	c := sysfs.CacheInfo{