add ut for psi

Signed-off-by: zouyee <zouyee1989@gmail.com>

cgroup2/utils.go

@@ -482,43 +482,43 @@ func getHugePageSizeFromFilenames(fileNames []string) ([]string, error) {
 func getStatPSIFromFile(path string) *stats.PSIStats {
 	f, err := os.Open(path)
 	if err != nil {
-		return &stats.PSIStats{}
+		return nil
 	}
 	defer f.Close()
 
-	var psistats stats.PSIStats
+	psistats := &stats.PSIStats{}
 	sc := bufio.NewScanner(f)
 	for sc.Scan() {
 		parts := strings.Fields(sc.Text())
 		var pv *stats.PSIData
 		switch parts[0] {
 		case "some":
-			psistats.Some = pv
+			psistats.Some = &stats.PSIData{}
 			pv = psistats.Some
 		case "full":
-			psistats.Full = pv
+			psistats.Full = &stats.PSIData{}
 			pv = psistats.Full
 		}
 		if pv != nil {
-			pv, err = parsePSIData(parts[1:])
+			err = parsePSIData(parts[1:], pv)
 			if err != nil {
 				logrus.Errorf("unable to parse psi data: %v", err)
-				return &stats.PSIStats{}
+				return nil
 			}
 		}
 	}
+
 	if err := sc.Err(); err != nil {
-		return &stats.PSIStats{}
+		return nil
 	}
-	return &psistats
+	return psistats
 }
 
-func parsePSIData(psi []string) (*stats.PSIData, error) {
-	data := &stats.PSIData{}
+func parsePSIData(psi []string, data *stats.PSIData) error {
 	for _, f := range psi {
 		kv := strings.SplitN(f, "=", 2)
 		if len(kv) != 2 {
-			return data, fmt.Errorf("invalid psi data: %q", f)
+			return fmt.Errorf("invalid psi data: %q", f)
 		}
 		var pv *float64
 		switch kv[0] {
@@ -531,19 +531,19 @@ func parsePSIData(psi []string) (*stats.PSIData, error) {
 		case "total":
 			v, err := strconv.ParseUint(kv[1], 10, 64)
 			if err != nil {
-				return data, fmt.Errorf("invalid %s PSI value: %w", kv[0], err)
+				return fmt.Errorf("invalid %s PSI value: %w", kv[0], err)
 			}
 			data.Total = v
 		}
 		if pv != nil {
 			v, err := strconv.ParseFloat(kv[1], 64)
 			if err != nil {
-				return data, fmt.Errorf("invalid %s PSI value: %w", kv[0], err)
+				return fmt.Errorf("invalid %s PSI value: %w", kv[0], err)
 			}
 			*pv = v
 		}
 	}
-	return data, nil
+	return nil
 }
 
 func getSubreaper() (int, error) {

cgroup2/utils_test.go

@@ -17,11 +17,17 @@
 package cgroup2
 
 import (
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
+	"github.com/containerd/cgroups/v3/cgroup2/stats"
+
+	"github.com/google/go-cmp/cmp"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/stretchr/testify/assert"
+	"google.golang.org/protobuf/testing/protocmp"
 )
 
 func TestParseCgroupFromReader(t *testing.T) {
@@ -41,6 +47,36 @@ func TestParseCgroupFromReader(t *testing.T) {
 	}
 }
 
+func TestParseStatCPUPSI(t *testing.T) {
+	const examplePSIData = `some avg10=1.71 avg60=2.36 avg300=2.57 total=230548833
+full avg10=1.00 avg60=1.01 avg300=1.00 total=157622356`
+
+	fakeCgroupDir := t.TempDir()
+	statPath := filepath.Join(fakeCgroupDir, "cpu.pressure")
+
+	if err := os.WriteFile(statPath, []byte(examplePSIData), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	st := getStatPSIFromFile(filepath.Join(fakeCgroupDir, "cpu.pressure"))
+	if diff := cmp.Diff(st, stats.PSIStats{
+		Some: &stats.PSIData{
+			Avg10:  1.71,
+			Avg60:  2.36,
+			Avg300: 2.57,
+			Total:  230548833,
+		},
+		Full: &stats.PSIData{
+			Avg10:  1.00,
+			Avg60:  1.01,
+			Avg300: 1.00,
+			Total:  157622356,
+		},
+	}, protocmp.Transform()); diff != "" {
+		t.Errorf("unexpected PSI result: %+v", diff)
+	}
+}
+
 func TestToResources(t *testing.T) {
 	var (
 		quota  int64  = 8000
@@ -63,6 +99,6 @@ func BenchmarkGetStatFileContentUint64(b *testing.B) {
 	b.ReportAllocs()
 
 	for i := 0; i < b.N; i++ {
-		_ = getStatFileContentUint64("/proc/self/loginuid")
+		_ = getStatFileContentUint64("/proc/self/2loginuid")
 	}
 }