helpers: fix reading cpu stats on cgroup v2

read quota and limit from cpu.max, and convert cpu.weight to the range
expected with cgroup v1.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

container/common/helpers.go

@@ -17,6 +17,7 @@ package common
 import (
 	"fmt"
 	"io/ioutil"
+	"math"
 	"os"
 	"path"
 	"path/filepath"
@@ -122,18 +123,43 @@ func GetSpec(cgroupPaths map[string]string, machineInfoFactory info.MachineInfoF
 	cpuRoot, ok := cgroupPaths["cpu"]
 	if ok {
 		if utils.FileExists(cpuRoot) {
-			spec.HasCpu = true
-			spec.Cpu.Limit = readUInt64(cpuRoot, "cpu.shares")
-			spec.Cpu.Period = readUInt64(cpuRoot, "cpu.cfs_period_us")
-			quota := readString(cpuRoot, "cpu.cfs_quota_us")
-
-			if quota != "" && quota != "-1" {
-				val, err := strconv.ParseUint(quota, 10, 64)
-				if err != nil {
-					klog.Errorf("GetSpec: Failed to parse CPUQuota from %q: %s", path.Join(cpuRoot, "cpu.cfs_quota_us"), err)
-				} else {
-					spec.Cpu.Quota = val
+			if !cgroups.IsCgroup2UnifiedMode() {
+				spec.HasCpu = true
+				spec.Cpu.Limit = readUInt64(cpuRoot, "cpu.shares")
+				spec.Cpu.Period = readUInt64(cpuRoot, "cpu.cfs_period_us")
+				quota := readString(cpuRoot, "cpu.cfs_quota_us")
+
+				if quota != "" && quota != "-1" {
+					val, err := strconv.ParseUint(quota, 10, 64)
+					if err != nil {
+						klog.Errorf("GetSpec: Failed to parse CPUQuota from %q: %s", path.Join(cpuRoot, "cpu.cfs_quota_us"), err)
+					} else {
+						spec.Cpu.Quota = val
+					}
+				}
+			} else {
+				spec.HasCpu = true
+
+				weight := readUInt64(cpuRoot, "cpu.weight")
+				if weight > 0 {
+					limit, err := convertCPUWeightToCPULimit(weight)
+					if err != nil {
+						klog.Errorf("GetSpec: Failed to read CPULimit from %q: %s", path.Join(cpuRoot, "cpu.weight"), err)
+					} else {
+						spec.Cpu.Limit = limit
+					}
 				}
+				max := readString(cpuRoot, "cpu.max")
+				if max != "" {
+					splits := strings.SplitN(max, " ", 2)
+					if len(splits) != 2 {
+						klog.Errorf("GetSpec: Failed to parse CPUmax from %q", path.Join(cpuRoot, "cpu.max"))
+					} else {
+						spec.Cpu.Quota = parseUint64String(splits[0])
+						spec.Cpu.Period = parseUint64String(splits[1])
+					}
+				}
+
 			}
 		}
 	}
@@ -224,6 +250,31 @@ func readString(dirpath string, file string) string {
 	return strings.TrimSpace(string(out))
 }
 
+// Convert from [1-10000] to [2-262144]
+func convertCPUWeightToCPULimit(weight uint64) (uint64, error) {
+	if weight < 1 || weight > 10000 {
+		return 0, fmt.Errorf("convertCPUWeightToCPULimit: invalid cpu weight: %v", weight)
+	}
+	return 2 + ((weight-1)*262142)/9999, nil
+}
+
+func parseUint64String(strValue string) uint64 {
+	if strValue == "max" {
+		return math.MaxUint64
+	}
+	if strValue == "" {
+		return 0
+	}
+
+	val, err := strconv.ParseUint(strValue, 10, 64)
+	if err != nil {
+		klog.Errorf("readUInt64: Failed to parse int %q: %s", strValue, err)
+		return 0
+	}
+
+	return val
+}
+
 func readUInt64(dirpath string, file string) uint64 {
 	out := readString(dirpath, file)
 	if out == "" || out == "max" {

container/common/helpers_test.go

@@ -26,3 +26,28 @@ func BenchmarkListDirectories(b *testing.B) {
 		}
 	}
 }
+
+func TestConvertCpuWeightToCpuLimit(t *testing.T) {
+	limit, err := convertCPUWeightToCPULimit(1)
+	if err != nil {
+		t.Fatalf("Error in convertCPUWeightToCPULimit: %s", err)
+	}
+	if limit != 2 {
+		t.Fatalf("convertCPUWeightToCPULimit(1) != 2")
+	}
+	limit, err = convertCPUWeightToCPULimit(10000)
+	if err != nil {
+		t.Fatalf("Error in convertCPUWeightToCPULimit: %s", err)
+	}
+	if limit != 262144 {
+		t.Fatalf("convertCPUWeightToCPULimit(10000) != 262144")
+	}
+	_, err = convertCPUWeightToCPULimit(0)
+	if err == nil {
+		t.Fatalf("convertCPUWeightToCPULimit(0) must raise an error")
+	}
+	_, err = convertCPUWeightToCPULimit(10001)
+	if err == nil {
+		t.Fatalf("convertCPUWeightToCPULimit(10001) must raise an error")
+	}
+}