libct/cg: make Set accept configs.Resources

A cgroup manager's Set method sets cgroup resources, but historically
it was accepting configs.Cgroups.

Refactor it to accept resources only. This is an improvement from the
API point of view, as the method can not change cgroup configuration
(such as path to the cgroup etc), it can only set (modify) its
resources/limits.

This also lays the foundation for complicated resource updates, as
now Set has two sets of resources -- the ones that were specified
on Apply, and the ones being set, so it could deduce the difference
between these. This is a long term goal though.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/cgroups/cgroups.go

@@ -30,7 +30,7 @@ type Manager interface {
 	Path(string) string
 
 	// Sets the cgroup as configured.
-	Set(container *configs.Config) error
+	Set(r *configs.Resources) error
 
 	// GetPaths returns cgroup path(s) to save in a state file in order to restore later.
 	//

libcontainer/cgroups/fs/blkio.go

@@ -25,42 +25,42 @@ func (s *BlkioGroup) Apply(path string, d *cgroupData) error {
 	return join(path, d.pid)
 }
 
-func (s *BlkioGroup) Set(path string, cgroup *configs.Cgroup) error {
-	if cgroup.Resources.BlkioWeight != 0 {
-		if err := fscommon.WriteFile(path, "blkio.weight", strconv.FormatUint(uint64(cgroup.Resources.BlkioWeight), 10)); err != nil {
+func (s *BlkioGroup) Set(path string, r *configs.Resources) error {
+	if r.BlkioWeight != 0 {
+		if err := fscommon.WriteFile(path, "blkio.weight", strconv.FormatUint(uint64(r.BlkioWeight), 10)); err != nil {
 			return err
 		}
 	}
 
-	if cgroup.Resources.BlkioLeafWeight != 0 {
-		if err := fscommon.WriteFile(path, "blkio.leaf_weight", strconv.FormatUint(uint64(cgroup.Resources.BlkioLeafWeight), 10)); err != nil {
+	if r.BlkioLeafWeight != 0 {
+		if err := fscommon.WriteFile(path, "blkio.leaf_weight", strconv.FormatUint(uint64(r.BlkioLeafWeight), 10)); err != nil {
 			return err
 		}
 	}
-	for _, wd := range cgroup.Resources.BlkioWeightDevice {
+	for _, wd := range r.BlkioWeightDevice {
 		if err := fscommon.WriteFile(path, "blkio.weight_device", wd.WeightString()); err != nil {
 			return err
 		}
 		if err := fscommon.WriteFile(path, "blkio.leaf_weight_device", wd.LeafWeightString()); err != nil {
 			return err
 		}
 	}
-	for _, td := range cgroup.Resources.BlkioThrottleReadBpsDevice {
+	for _, td := range r.BlkioThrottleReadBpsDevice {
 		if err := fscommon.WriteFile(path, "blkio.throttle.read_bps_device", td.String()); err != nil {
 			return err
 		}
 	}
-	for _, td := range cgroup.Resources.BlkioThrottleWriteBpsDevice {
+	for _, td := range r.BlkioThrottleWriteBpsDevice {
 		if err := fscommon.WriteFile(path, "blkio.throttle.write_bps_device", td.String()); err != nil {
 			return err
 		}
 	}
-	for _, td := range cgroup.Resources.BlkioThrottleReadIOPSDevice {
+	for _, td := range r.BlkioThrottleReadIOPSDevice {
 		if err := fscommon.WriteFile(path, "blkio.throttle.read_iops_device", td.String()); err != nil {
 			return err
 		}
 	}
-	for _, td := range cgroup.Resources.BlkioThrottleWriteIOPSDevice {
+	for _, td := range r.BlkioThrottleWriteIOPSDevice {
 		if err := fscommon.WriteFile(path, "blkio.throttle.write_iops_device", td.String()); err != nil {
 			return err
 		}

libcontainer/cgroups/fs/blkio_test.go

@@ -185,7 +185,7 @@ func TestBlkioSetWeight(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioWeight = weightAfter
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -216,7 +216,7 @@ func TestBlkioSetWeightDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioWeightDevice = []*configs.WeightDevice{wd}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -253,7 +253,7 @@ func TestBlkioSetMultipleWeightDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioWeightDevice = []*configs.WeightDevice{wd1, wd2}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -746,7 +746,7 @@ func TestBlkioSetThrottleReadBpsDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioThrottleReadBpsDevice = []*configs.ThrottleDevice{td}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -776,7 +776,7 @@ func TestBlkioSetThrottleWriteBpsDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioThrottleWriteBpsDevice = []*configs.ThrottleDevice{td}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -806,7 +806,7 @@ func TestBlkioSetThrottleReadIOpsDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioThrottleReadIOPSDevice = []*configs.ThrottleDevice{td}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -836,7 +836,7 @@ func TestBlkioSetThrottleWriteIOpsDevice(t *testing.T) {
 
 	helper.CgroupData.config.Resources.BlkioThrottleWriteIOPSDevice = []*configs.ThrottleDevice{td}
 	blkio := &BlkioGroup{}
-	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := blkio.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 

libcontainer/cgroups/fs/cpu.go

@@ -32,31 +32,31 @@ func (s *CpuGroup) Apply(path string, d *cgroupData) error {
 	// We should set the real-Time group scheduling settings before moving
 	// in the process because if the process is already in SCHED_RR mode
 	// and no RT bandwidth is set, adding it will fail.
-	if err := s.SetRtSched(path, d.config); err != nil {
+	if err := s.SetRtSched(path, d.config.Resources); err != nil {
 		return err
 	}
 	// Since we are not using join(), we need to place the pid
 	// into the procs file unlike other subsystems.
 	return cgroups.WriteCgroupProc(path, d.pid)
 }
 
-func (s *CpuGroup) SetRtSched(path string, cgroup *configs.Cgroup) error {
-	if cgroup.Resources.CpuRtPeriod != 0 {
-		if err := fscommon.WriteFile(path, "cpu.rt_period_us", strconv.FormatUint(cgroup.Resources.CpuRtPeriod, 10)); err != nil {
+func (s *CpuGroup) SetRtSched(path string, r *configs.Resources) error {
+	if r.CpuRtPeriod != 0 {
+		if err := fscommon.WriteFile(path, "cpu.rt_period_us", strconv.FormatUint(r.CpuRtPeriod, 10)); err != nil {
 			return err
 		}
 	}
-	if cgroup.Resources.CpuRtRuntime != 0 {
-		if err := fscommon.WriteFile(path, "cpu.rt_runtime_us", strconv.FormatInt(cgroup.Resources.CpuRtRuntime, 10)); err != nil {
+	if r.CpuRtRuntime != 0 {
+		if err := fscommon.WriteFile(path, "cpu.rt_runtime_us", strconv.FormatInt(r.CpuRtRuntime, 10)); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func (s *CpuGroup) Set(path string, cgroup *configs.Cgroup) error {
-	if cgroup.Resources.CpuShares != 0 {
-		shares := cgroup.Resources.CpuShares
+func (s *CpuGroup) Set(path string, r *configs.Resources) error {
+	if r.CpuShares != 0 {
+		shares := r.CpuShares
 		if err := fscommon.WriteFile(path, "cpu.shares", strconv.FormatUint(shares, 10)); err != nil {
 			return err
 		}
@@ -72,17 +72,17 @@ func (s *CpuGroup) Set(path string, cgroup *configs.Cgroup) error {
 			return fmt.Errorf("the minimum allowed cpu-shares is %d", sharesRead)
 		}
 	}
-	if cgroup.Resources.CpuPeriod != 0 {
-		if err := fscommon.WriteFile(path, "cpu.cfs_period_us", strconv.FormatUint(cgroup.Resources.CpuPeriod, 10)); err != nil {
+	if r.CpuPeriod != 0 {
+		if err := fscommon.WriteFile(path, "cpu.cfs_period_us", strconv.FormatUint(r.CpuPeriod, 10)); err != nil {
 			return err
 		}
 	}
-	if cgroup.Resources.CpuQuota != 0 {
-		if err := fscommon.WriteFile(path, "cpu.cfs_quota_us", strconv.FormatInt(cgroup.Resources.CpuQuota, 10)); err != nil {
+	if r.CpuQuota != 0 {
+		if err := fscommon.WriteFile(path, "cpu.cfs_quota_us", strconv.FormatInt(r.CpuQuota, 10)); err != nil {
 			return err
 		}
 	}
-	return s.SetRtSched(path, cgroup)
+	return s.SetRtSched(path, r)
 }
 
 func (s *CpuGroup) GetStats(path string, stats *cgroups.Stats) error {

libcontainer/cgroups/fs/cpu_test.go

@@ -26,7 +26,7 @@ func TestCpuSetShares(t *testing.T) {
 
 	helper.CgroupData.config.Resources.CpuShares = sharesAfter
 	cpu := &CpuGroup{}
-	if err := cpu.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := cpu.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -67,7 +67,7 @@ func TestCpuSetBandWidth(t *testing.T) {
 	helper.CgroupData.config.Resources.CpuRtRuntime = rtRuntimeAfter
 	helper.CgroupData.config.Resources.CpuRtPeriod = rtPeriodAfter
 	cpu := &CpuGroup{}
-	if err := cpu.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := cpu.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 

libcontainer/cgroups/fs/cpuacct.go

@@ -43,7 +43,7 @@ func (s *CpuacctGroup) Apply(path string, d *cgroupData) error {
 	return join(path, d.pid)
 }
 
-func (s *CpuacctGroup) Set(path string, cgroup *configs.Cgroup) error {
+func (s *CpuacctGroup) Set(_ string, _ *configs.Resources) error {
 	return nil
 }
 

libcontainer/cgroups/fs/cpuset.go

@@ -24,17 +24,17 @@ func (s *CpusetGroup) Name() string {
 }
 
 func (s *CpusetGroup) Apply(path string, d *cgroupData) error {
-	return s.ApplyDir(path, d.config, d.pid)
+	return s.ApplyDir(path, d.config.Resources, d.pid)
 }
 
-func (s *CpusetGroup) Set(path string, cgroup *configs.Cgroup) error {
-	if cgroup.Resources.CpusetCpus != "" {
-		if err := fscommon.WriteFile(path, "cpuset.cpus", cgroup.Resources.CpusetCpus); err != nil {
+func (s *CpusetGroup) Set(path string, r *configs.Resources) error {
+	if r.CpusetCpus != "" {
+		if err := fscommon.WriteFile(path, "cpuset.cpus", r.CpusetCpus); err != nil {
 			return err
 		}
 	}
-	if cgroup.Resources.CpusetMems != "" {
-		if err := fscommon.WriteFile(path, "cpuset.mems", cgroup.Resources.CpusetMems); err != nil {
+	if r.CpusetMems != "" {
+		if err := fscommon.WriteFile(path, "cpuset.mems", r.CpusetMems); err != nil {
 			return err
 		}
 	}
@@ -144,7 +144,7 @@ func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
 	return nil
 }
 
-func (s *CpusetGroup) ApplyDir(dir string, cgroup *configs.Cgroup, pid int) error {
+func (s *CpusetGroup) ApplyDir(dir string, r *configs.Resources, pid int) error {
 	// This might happen if we have no cpuset cgroup mounted.
 	// Just do nothing and don't fail.
 	if dir == "" {
@@ -166,7 +166,7 @@ func (s *CpusetGroup) ApplyDir(dir string, cgroup *configs.Cgroup, pid int) erro
 	// specified configs, otherwise, inherit from parent. This makes
 	// cpuset configs work correctly with 'cpuset.cpu_exclusive', and
 	// keep backward compatibility.
-	if err := s.ensureCpusAndMems(dir, cgroup); err != nil {
+	if err := s.ensureCpusAndMems(dir, r); err != nil {
 		return err
 	}
 
@@ -241,8 +241,8 @@ func isEmptyCpuset(str string) bool {
 	return str == "" || str == "\n"
 }
 
-func (s *CpusetGroup) ensureCpusAndMems(path string, cgroup *configs.Cgroup) error {
-	if err := s.Set(path, cgroup); err != nil {
+func (s *CpusetGroup) ensureCpusAndMems(path string, r *configs.Resources) error {
+	if err := s.Set(path, r); err != nil {
 		return err
 	}
 	return cpusetCopyIfNeeded(path, filepath.Dir(path))

libcontainer/cgroups/fs/cpuset_test.go

@@ -53,7 +53,7 @@ func TestCPUSetSetCpus(t *testing.T) {
 
 	helper.CgroupData.config.Resources.CpusetCpus = cpusAfter
 	cpuset := &CpusetGroup{}
-	if err := cpuset.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := cpuset.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -82,7 +82,7 @@ func TestCPUSetSetMems(t *testing.T) {
 
 	helper.CgroupData.config.Resources.CpusetMems = memsAfter
 	cpuset := &CpusetGroup{}
-	if err := cpuset.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := cpuset.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 

libcontainer/cgroups/fs/devices.go

@@ -54,8 +54,8 @@ func buildEmulator(rules []*devices.Rule) (*cgroupdevices.Emulator, error) {
 	return emu, nil
 }
 
-func (s *DevicesGroup) Set(path string, cgroup *configs.Cgroup) error {
-	if userns.RunningInUserNS() || cgroup.SkipDevices {
+func (s *DevicesGroup) Set(path string, r *configs.Resources) error {
+	if userns.RunningInUserNS() || r.SkipDevices {
 		return nil
 	}
 
@@ -65,7 +65,7 @@ func (s *DevicesGroup) Set(path string, cgroup *configs.Cgroup) error {
 	if err != nil {
 		return err
 	}
-	target, err := buildEmulator(cgroup.Resources.Devices)
+	target, err := buildEmulator(r.Devices)
 	if err != nil {
 		return err
 	}

libcontainer/cgroups/fs/devices_test.go

@@ -30,7 +30,7 @@ func TestDevicesSetAllow(t *testing.T) {
 	}
 
 	d := &DevicesGroup{testingSkipFinalCheck: true}
-	if err := d.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := d.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 

libcontainer/cgroups/fs/freezer.go

@@ -27,8 +27,8 @@ func (s *FreezerGroup) Apply(path string, d *cgroupData) error {
 	return join(path, d.pid)
 }
 
-func (s *FreezerGroup) Set(path string, cgroup *configs.Cgroup) error {
-	switch cgroup.Resources.Freezer {
+func (s *FreezerGroup) Set(path string, r *configs.Resources) error {
+	switch r.Freezer {
 	case configs.Frozen:
 		// As per older kernel docs (freezer-subsystem.txt before
 		// kernel commit ef9fe980c6fcc1821), if FREEZING is seen,
@@ -84,7 +84,7 @@ func (s *FreezerGroup) Set(path string, cgroup *configs.Cgroup) error {
 	case configs.Undefined:
 		return nil
 	default:
-		return fmt.Errorf("Invalid argument '%s' to freezer.state", string(cgroup.Resources.Freezer))
+		return fmt.Errorf("Invalid argument '%s' to freezer.state", string(r.Freezer))
 	}
 }
 

libcontainer/cgroups/fs/freezer_test.go

@@ -19,7 +19,7 @@ func TestFreezerSetState(t *testing.T) {
 
 	helper.CgroupData.config.Resources.Freezer = configs.Thawed
 	freezer := &FreezerGroup{}
-	if err := freezer.Set(helper.CgroupPath, helper.CgroupData.config); err != nil {
+	if err := freezer.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err != nil {
 		t.Fatal(err)
 	}
 
@@ -42,7 +42,7 @@ func TestFreezerSetInvalidState(t *testing.T) {
 
 	helper.CgroupData.config.Resources.Freezer = invalidArg
 	freezer := &FreezerGroup{}
-	if err := freezer.Set(helper.CgroupPath, helper.CgroupData.config); err == nil {
+	if err := freezer.Set(helper.CgroupPath, helper.CgroupData.config.Resources); err == nil {
 		t.Fatal("Failed to return invalid argument error")
 	}
 }