libct/cg/sd: write rounded CPU quota to cgroupfs

libcontainer/cgroups/systemd/common.go

@@ -314,6 +314,26 @@ func addCpuQuota(cm *dbusConnManager, properties *[]systemdDbus.Property, quota
 	}
 }
 
+func getCPUQuotaFromProperties(properties []systemdDbus.Property, period uint64) (int64, error) {
+	var cpuQuotaPerSecUsec int64
+
+	for _, prop := range properties {
+		if prop.Name == "CPUQuotaPerSecUSec" {
+			if err := prop.Value.Store(&cpuQuotaPerSecUsec); err != nil {
+				return 0, fmt.Errorf("can't parse CPUQuotaPerSecUSec %v: %w", prop.Value, err)
+			}
+			break
+		}
+	}
+	if cpuQuotaPerSecUsec == 0 {
+		return 0, nil
+	}
+	if period == 0 {
+		period = defCPUQuotaPeriod
+	}
+	return cpuQuotaPerSecUsec * int64(period) / 1000000, nil
+}
+
 func addCpuset(cm *dbusConnManager, props *[]systemdDbus.Property, cpus, mems string) error {
 	if cpus == "" && mems == "" {
 		return nil

libcontainer/cgroups/systemd/systemd_test.go

@@ -178,3 +178,64 @@ func TestUnifiedResToSystemdProps(t *testing.T) {
 		})
 	}
 }
+
+func TestGetCPUQuotaFromProperties(t *testing.T) {
+	testCases := []struct {
+		name             string
+		properties       []systemdDbus.Property
+		cpuPeriod        uint64
+		expectedCPUQuota int64
+	}{
+		{
+			name: "Update only CPU quota",
+			properties: []systemdDbus.Property{
+				newProp("CPUQuotaPerSecUSec", 1230000),
+			},
+			cpuPeriod:        0,
+			expectedCPUQuota: 123000,
+		},
+		{
+			name: "Update CPU Quota and CPU period",
+			properties: []systemdDbus.Property{
+				newProp("CPUQuotaPerSecUSec", 560000),
+				newProp("CPUQuotaPeriodUSec", 900000),
+			},
+			cpuPeriod:        900000,
+			expectedCPUQuota: 504000,
+		},
+		{
+			name: "Update CPU Quota and CPU period without supporting CPUQuotaPeriodUSec",
+			properties: []systemdDbus.Property{
+				newProp("CPUQuotaPerSecUSec", 560000),
+			},
+			cpuPeriod:        900000,
+			expectedCPUQuota: 504000,
+		},
+		{
+			name: "Update only CPU period",
+			properties: []systemdDbus.Property{
+				newProp("CPUQuotaPeriodUSec", 900000),
+			},
+			cpuPeriod:        900000,
+			expectedCPUQuota: 0,
+		},
+		{
+			name: "Update neither CPU quota nor CPU period",
+			properties: []systemdDbus.Property{
+				newProp("MemoryMax", 67108864),
+			},
+			cpuPeriod:        0,
+			expectedCPUQuota: 0,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if cpuQuota, err := getCPUQuotaFromProperties(tc.properties, tc.cpuPeriod); err != nil {
+				t.Errorf("getCPUQuotaFromProperties(%v); unexpected error %v", tc.properties, err)
+			} else if cpuQuota != tc.expectedCPUQuota {
+				t.Errorf("getCPUQuotaFromProperties(%v); want %d; got %d", tc.properties, tc.expectedCPUQuota, cpuQuota)
+			}
+		})
+	}
+}

libcontainer/cgroups/systemd/v1.go

@@ -370,6 +370,16 @@ func (m *LegacyManager) Set(r *cgroups.Resources) error {
 		return setErr
 	}
 
+	if cpuQuota, err := getCPUQuotaFromProperties(properties, r.CpuPeriod); err != nil {
+		return err
+	} else if cpuQuota > 0 {
+		// CPU Quota is rounded up to the nearest 10ms in properties.
+		// Get the rounded value in order to write the same value to the file.
+		rCopy := *r
+		r = &rCopy
+		r.CpuQuota = cpuQuota
+	}
+
 	for _, sys := range legacySubsystems {
 		// Get the subsystem path, but don't error out for not found cgroups.
 		path, ok := m.paths[sys.Name()]

libcontainer/cgroups/systemd/v2.go

@@ -489,6 +489,16 @@ func (m *UnifiedManager) Set(r *cgroups.Resources) error {
 		return fmt.Errorf("unable to set unit properties: %w", err)
 	}
 
+	if cpuQuota, err := getCPUQuotaFromProperties(properties, r.CpuPeriod); err != nil {
+		return err
+	} else if cpuQuota > 0 {
+		// CPU Quota is rounded up to the nearest 10ms in properties.
+		// Get the rounded value in order to write the same value to the file.
+		rCopy := *r
+		r = &rCopy
+		r.CpuQuota = cpuQuota
+	}
+
 	return m.fsMgr.Set(r)
 }
 

tests/integration/update.bats

@@ -267,15 +267,37 @@ EOF
 	check_cpu_quota 500000 1000000 "500ms"
 	check_cpu_shares 100
 
+	# update cpu quota with fraction
+	runc update test_update --cpu-quota 123456
+	[ "$status" -eq 0 ]
+	expected_quota=123456
+	if [ -v RUNC_USE_SYSTEMD ]; then
+		expected_quota=130000
+	fi
+	check_cpu_quota $expected_quota 1000000 "130ms"
+
+	# update cpu quota to original value
+	runc update test_update --cpu-quota 500000
+	[ "$status" -eq 0 ]
+	check_cpu_quota 500000 1000000 "500ms"
+
 	# update cpu period
 	runc update test_update --cpu-period 900000
 	[ "$status" -eq 0 ]
-	check_cpu_quota 500000 900000 "560ms"
+	expected_quota=500000
+	if [ -v RUNC_USE_SYSTEMD ]; then
+		expected_quota=504000
+	fi
+	check_cpu_quota $expected_quota 900000 "560ms"
 
 	# update cpu quota
 	runc update test_update --cpu-quota 600000
 	[ "$status" -eq 0 ]
-	check_cpu_quota 600000 900000 "670ms"
+	expected_quota=600000
+	if [ -v RUNC_USE_SYSTEMD ]; then
+		expected_quota=603000
+	fi
+	check_cpu_quota $expected_quota 900000 "670ms"
 
 	# remove cpu quota
 	runc update test_update --cpu-quota -1
@@ -304,7 +326,11 @@ EOF
 	runc update test_update \
 		--cpu-period 900000 --cpu-quota 600000 --cpu-share 200
 	[ "$status" -eq 0 ]
-	check_cpu_quota 600000 900000 "670ms"
+	expected_quota=600000
+	if [ -v RUNC_USE_SYSTEMD ]; then
+		expected_quota=603000
+	fi
+	check_cpu_quota $expected_quota 900000 "670ms"
 	check_cpu_shares 200
 
 	# remove cpu quota and reset the period