Revert "cgroups: add pids controller support"

Signed-off-by: Mrunal Patel <mrunalp@gmail.com>

libcontainer/cgroups/fs/apply_raw.go

@@ -23,7 +23,6 @@ var (
 		&MemoryGroup{},
 		&CpuGroup{},
 		&CpuacctGroup{},
-		&PidsGroup{},
 		&BlkioGroup{},
 		&HugetlbGroup{},
 		&NetClsGroup{},
@@ -180,24 +179,11 @@ func (m *Manager) GetStats() (*cgroups.Stats, error) {
 }
 
 func (m *Manager) Set(container *configs.Config) error {
-	for _, sys := range subsystems {
-		// We can't set this here, because after being applied, memcg doesn't
-		// allow a non-empty cgroup from having its limits changed.
-		if sys.Name() == "memory" {
+	for name, path := range m.Paths {
+		sys, err := subsystems.Get(name)
+		if err == errSubsystemDoesNotExist || !cgroups.PathExists(path) {
 			continue
 		}
-
-		// Generate fake cgroup data.
-		d, err := getCgroupData(container.Cgroups, -1)
-		if err != nil {
-			return err
-		}
-		// Get the path, but don't error out if the cgroup wasn't found.
-		path, err := d.path(sys.Name())
-		if err != nil && !cgroups.IsNotFound(err) {
-			return err
-		}
-
 		if err := sys.Set(path, container.Cgroups); err != nil {
 			return err
 		}

libcontainer/cgroups/fs/blkio.go

@@ -22,10 +22,15 @@ func (s *BlkioGroup) Name() string {
 }
 
 func (s *BlkioGroup) Apply(d *cgroupData) error {
-	_, err := d.join("blkio")
+	dir, err := d.join("blkio")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/cpu.go

@@ -22,10 +22,15 @@ func (s *CpuGroup) Name() string {
 func (s *CpuGroup) Apply(d *cgroupData) error {
 	// We always want to join the cpu group, to allow fair cpu scheduling
 	// on a container basis
-	_, err := d.join("cpu")
+	dir, err := d.join("cpu")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/cpuset.go

@@ -63,6 +63,11 @@ func (s *CpusetGroup) ApplyDir(dir string, cgroup *configs.Cgroup, pid int) erro
 	if err := s.ensureParent(dir, root); err != nil {
 		return err
 	}
+	// the default values inherit from parent cgroup are already set in
+	// s.ensureParent, cover these if we have our own
+	if err := s.Set(dir, cgroup); err != nil {
+		return err
+	}
 	// because we are not using d.join we need to place the pid into the procs file
 	// unlike the other subsystems
 	if err := writeFile(dir, "cgroup.procs", strconv.Itoa(pid)); err != nil {

libcontainer/cgroups/fs/devices.go

@@ -15,12 +15,17 @@ func (s *DevicesGroup) Name() string {
 }
 
 func (s *DevicesGroup) Apply(d *cgroupData) error {
-	_, err := d.join("devices")
+	dir, err := d.join("devices")
 	if err != nil {
 		// We will return error even it's `not found` error, devices
 		// cgroup is hard requirement for container's security.
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/freezer.go

@@ -19,10 +19,15 @@ func (s *FreezerGroup) Name() string {
 }
 
 func (s *FreezerGroup) Apply(d *cgroupData) error {
-	_, err := d.join("freezer")
+	dir, err := d.join("freezer")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/hugetlb.go

@@ -19,10 +19,15 @@ func (s *HugetlbGroup) Name() string {
 }
 
 func (s *HugetlbGroup) Apply(d *cgroupData) error {
-	_, err := d.join("hugetlb")
+	dir, err := d.join("hugetlb")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/memory.go

@@ -32,6 +32,7 @@ func (s *MemoryGroup) Apply(d *cgroupData) (err error) {
 				return err
 			}
 		}
+
 		if err := s.Set(path, d.config); err != nil {
 			return err
 		}

libcontainer/cgroups/fs/net_cls.go

@@ -15,10 +15,15 @@ func (s *NetClsGroup) Name() string {
 }
 
 func (s *NetClsGroup) Apply(d *cgroupData) error {
-	_, err := d.join("net_cls")
+	dir, err := d.join("net_cls")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/fs/net_prio.go

@@ -15,10 +15,15 @@ func (s *NetPrioGroup) Name() string {
 }
 
 func (s *NetPrioGroup) Apply(d *cgroupData) error {
-	_, err := d.join("net_prio")
+	dir, err := d.join("net_prio")
 	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
+
+	if err := s.Set(dir, d.config); err != nil {
+		return err
+	}
+
 	return nil
 }
 

libcontainer/cgroups/stats.go

@@ -49,11 +49,6 @@ type MemoryStats struct {
 	Stats       map[string]uint64 `json:"stats,omitempty"`
 }
 
-type PidsStats struct {
-	// number of pids in the cgroup
-	Current uint64 `json:"current,omitempty"`
-}
-
 type BlkioStatEntry struct {
 	Major uint64 `json:"major,omitempty"`
 	Minor uint64 `json:"minor,omitempty"`
@@ -85,7 +80,6 @@ type HugetlbStats struct {
 type Stats struct {
 	CpuStats    CpuStats    `json:"cpu_stats,omitempty"`
 	MemoryStats MemoryStats `json:"memory_stats,omitempty"`
-	PidsStats   PidsStats   `json:"pids_stats,omitempty"`
 	BlkioStats  BlkioStats  `json:"blkio_stats,omitempty"`
 	// the map is in the format "size of hugepage: stats of the hugepage"
 	HugetlbStats map[string]HugetlbStats `json:"hugetlb_stats,omitempty"`