add swap support in nfd

pkg/utils/hostpath/hostpath.go

@@ -34,6 +34,8 @@ var (
 	VarDir = HostDir(pathPrefix + "var")
 	// LibDir is where the /lib directory of the system to be inspected is located
 	LibDir = HostDir(pathPrefix + "lib")
+	// ProcDir is where the /proc directory of the system to be inspected is located
+	ProcDir = HostDir(pathPrefix + "proc")
 )
 
 // HostDir is a helper for handling host system directories

source/memory/memory.go

@@ -17,6 +17,7 @@ limitations under the License.
 package memory
 
 import (
+	"encoding/csv"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -40,6 +41,9 @@ const NvFeature = "nv"
 // NumaFeature is the name of the feature set that holds all NUMA related features.
 const NumaFeature = "numa"
 
+// SwapFeature is the name of the feature set that holds all Swap related features
+const SwapFeature = "swap"
+
 // memorySource implements the FeatureSource and LabelSource interfaces.
 type memorySource struct {
 	features *nfdv1alpha1.Features
@@ -68,6 +72,11 @@ func (s *memorySource) GetLabels() (source.FeatureLabels, error) {
 		labels["numa"] = true
 	}
 
+	// Swap
+	if isSwap, ok := features.Attributes[SwapFeature].Elements["is_swap"]; ok && isSwap == "true" {
+		labels["swap"] = true
+	}
+
 	// NVDIMM
 	if len(features.Instances[NvFeature].Elements) > 0 {
 		labels["nv.present"] = true
@@ -93,6 +102,13 @@ func (s *memorySource) Discover() error {
 		s.features.Attributes[NumaFeature] = nfdv1alpha1.AttributeFeatureSet{Elements: numa}
 	}
 
+	// Detect Swap
+	if swap, err := detectSwap(); err != nil {
+		klog.ErrorS(err, "failed to detect Swap nodes")
+	} else {
+		s.features.Attributes[SwapFeature] = nfdv1alpha1.AttributeFeatureSet{Elements: swap}
+	}
+
 	// Detect NVDIMM
 	if nv, err := detectNv(); err != nil {
 		klog.ErrorS(err, "failed to detect nvdimm devices")
@@ -113,6 +129,29 @@ func (s *memorySource) GetFeatures() *nfdv1alpha1.Features {
 	return s.features
 }
 
+// detectSwap detects Swap node information
+func detectSwap() (map[string]string, error) {
+	procBasePath := hostpath.ProcDir.Path("swaps")
+	file, err := os.Open(procBasePath)
+	defer file.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	// Read the CSV data
+	reader := csv.NewReader(file)
+	reader.FieldsPerRecord = -1 // Allow variable number of fields
+	data, err := reader.ReadAll()
+	if err != nil {
+		return nil, err
+	}
+	// /proc/swaps has a header row
+	// If there is more than a header then we assume we have swap.
+	return map[string]string{
+		"is_swap": strconv.FormatBool(len(data[0]) > 1),
+	}, nil
+}
+
 // detectNuma detects NUMA node information
 func detectNuma() (map[string]string, error) {
 	sysfsBasePath := hostpath.SysfsDir.Path("bus/node/devices")