mirror of https://github.com/containers/podman.git
491 lines
10 KiB
Go
491 lines
10 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cgroups
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import (
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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"sync"
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specs "github.com/opencontainers/runtime-spec/specs-go"
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"github.com/pkg/errors"
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)
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// New returns a new control via the cgroup cgroups interface
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func New(hierarchy Hierarchy, path Path, resources *specs.LinuxResources) (Cgroup, error) {
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subsystems, err := hierarchy()
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if err != nil {
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return nil, err
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}
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for _, s := range subsystems {
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if err := initializeSubsystem(s, path, resources); err != nil {
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return nil, err
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}
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}
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return &cgroup{
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path: path,
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subsystems: subsystems,
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}, nil
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}
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// Load will load an existing cgroup and allow it to be controlled
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func Load(hierarchy Hierarchy, path Path) (Cgroup, error) {
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var activeSubsystems []Subsystem
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subsystems, err := hierarchy()
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if err != nil {
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return nil, err
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}
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// check that the subsystems still exist, and keep only those that actually exist
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for _, s := range pathers(subsystems) {
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p, err := path(s.Name())
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if err != nil {
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if os.IsNotExist(errors.Cause(err)) {
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return nil, ErrCgroupDeleted
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}
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return nil, err
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}
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if _, err := os.Lstat(s.Path(p)); err != nil {
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if os.IsNotExist(err) {
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continue
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}
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return nil, err
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}
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activeSubsystems = append(activeSubsystems, s)
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}
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return &cgroup{
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path: path,
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subsystems: activeSubsystems,
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}, nil
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}
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type cgroup struct {
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path Path
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subsystems []Subsystem
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mu sync.Mutex
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err error
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}
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// New returns a new sub cgroup
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func (c *cgroup) New(name string, resources *specs.LinuxResources) (Cgroup, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return nil, c.err
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}
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path := subPath(c.path, name)
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for _, s := range c.subsystems {
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if err := initializeSubsystem(s, path, resources); err != nil {
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return nil, err
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}
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}
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return &cgroup{
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path: path,
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subsystems: c.subsystems,
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}, nil
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}
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// Subsystems returns all the subsystems that are currently being
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// consumed by the group
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func (c *cgroup) Subsystems() []Subsystem {
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return c.subsystems
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}
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// Add moves the provided process into the new cgroup
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func (c *cgroup) Add(process Process) error {
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if process.Pid <= 0 {
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return ErrInvalidPid
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}
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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return c.add(process)
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}
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func (c *cgroup) add(process Process) error {
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for _, s := range pathers(c.subsystems) {
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p, err := c.path(s.Name())
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(
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filepath.Join(s.Path(p), cgroupProcs),
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[]byte(strconv.Itoa(process.Pid)),
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defaultFilePerm,
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); err != nil {
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return err
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}
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}
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return nil
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}
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// AddTask moves the provided tasks (threads) into the new cgroup
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func (c *cgroup) AddTask(process Process) error {
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if process.Pid <= 0 {
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return ErrInvalidPid
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}
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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return c.addTask(process)
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}
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func (c *cgroup) addTask(process Process) error {
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for _, s := range pathers(c.subsystems) {
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p, err := c.path(s.Name())
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(
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filepath.Join(s.Path(p), cgroupTasks),
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[]byte(strconv.Itoa(process.Pid)),
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defaultFilePerm,
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); err != nil {
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return err
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}
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}
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return nil
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}
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// Delete will remove the control group from each of the subsystems registered
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func (c *cgroup) Delete() error {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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var errors []string
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for _, s := range c.subsystems {
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if d, ok := s.(deleter); ok {
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sp, err := c.path(s.Name())
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if err != nil {
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return err
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}
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if err := d.Delete(sp); err != nil {
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errors = append(errors, string(s.Name()))
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}
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continue
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}
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if p, ok := s.(pather); ok {
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sp, err := c.path(s.Name())
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if err != nil {
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return err
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}
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path := p.Path(sp)
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if err := remove(path); err != nil {
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errors = append(errors, path)
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}
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}
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}
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if len(errors) > 0 {
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return fmt.Errorf("cgroups: unable to remove paths %s", strings.Join(errors, ", "))
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}
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c.err = ErrCgroupDeleted
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return nil
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}
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// Stat returns the current metrics for the cgroup
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func (c *cgroup) Stat(handlers ...ErrorHandler) (*Metrics, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return nil, c.err
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}
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if len(handlers) == 0 {
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handlers = append(handlers, errPassthrough)
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}
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var (
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stats = &Metrics{
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CPU: &CPUStat{
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Throttling: &Throttle{},
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Usage: &CPUUsage{},
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},
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}
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wg = &sync.WaitGroup{}
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errs = make(chan error, len(c.subsystems))
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)
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for _, s := range c.subsystems {
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if ss, ok := s.(stater); ok {
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sp, err := c.path(s.Name())
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if err != nil {
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return nil, err
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}
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wg.Add(1)
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go func() {
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defer wg.Done()
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if err := ss.Stat(sp, stats); err != nil {
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for _, eh := range handlers {
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if herr := eh(err); herr != nil {
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errs <- herr
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}
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}
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}
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}()
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}
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}
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wg.Wait()
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close(errs)
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for err := range errs {
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return nil, err
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}
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return stats, nil
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}
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// Update updates the cgroup with the new resource values provided
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//
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// Be prepared to handle EBUSY when trying to update a cgroup with
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// live processes and other operations like Stats being performed at the
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// same time
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func (c *cgroup) Update(resources *specs.LinuxResources) error {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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for _, s := range c.subsystems {
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if u, ok := s.(updater); ok {
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sp, err := c.path(s.Name())
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if err != nil {
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return err
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}
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if err := u.Update(sp, resources); err != nil {
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return err
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}
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}
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}
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return nil
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}
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// Processes returns the processes running inside the cgroup along
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// with the subsystem used, pid, and path
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func (c *cgroup) Processes(subsystem Name, recursive bool) ([]Process, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return nil, c.err
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}
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return c.processes(subsystem, recursive)
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}
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func (c *cgroup) processes(subsystem Name, recursive bool) ([]Process, error) {
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s := c.getSubsystem(subsystem)
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sp, err := c.path(subsystem)
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if err != nil {
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return nil, err
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}
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path := s.(pather).Path(sp)
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var processes []Process
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err = filepath.Walk(path, func(p string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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if !recursive && info.IsDir() {
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if p == path {
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return nil
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}
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return filepath.SkipDir
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}
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dir, name := filepath.Split(p)
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if name != cgroupProcs {
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return nil
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}
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procs, err := readPids(dir, subsystem)
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if err != nil {
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return err
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}
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processes = append(processes, procs...)
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return nil
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})
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return processes, err
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}
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// Tasks returns the tasks running inside the cgroup along
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// with the subsystem used, pid, and path
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func (c *cgroup) Tasks(subsystem Name, recursive bool) ([]Task, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return nil, c.err
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}
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return c.tasks(subsystem, recursive)
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}
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func (c *cgroup) tasks(subsystem Name, recursive bool) ([]Task, error) {
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s := c.getSubsystem(subsystem)
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sp, err := c.path(subsystem)
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if err != nil {
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return nil, err
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}
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path := s.(pather).Path(sp)
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var tasks []Task
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err = filepath.Walk(path, func(p string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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if !recursive && info.IsDir() {
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if p == path {
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return nil
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}
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return filepath.SkipDir
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}
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dir, name := filepath.Split(p)
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if name != cgroupTasks {
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return nil
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}
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procs, err := readTasksPids(dir, subsystem)
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if err != nil {
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return err
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}
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tasks = append(tasks, procs...)
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return nil
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})
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return tasks, err
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}
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// Freeze freezes the entire cgroup and all the processes inside it
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func (c *cgroup) Freeze() error {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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s := c.getSubsystem(Freezer)
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if s == nil {
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return ErrFreezerNotSupported
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}
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sp, err := c.path(Freezer)
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if err != nil {
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return err
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}
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return s.(*freezerController).Freeze(sp)
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}
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// Thaw thaws out the cgroup and all the processes inside it
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func (c *cgroup) Thaw() error {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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s := c.getSubsystem(Freezer)
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if s == nil {
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return ErrFreezerNotSupported
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}
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sp, err := c.path(Freezer)
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if err != nil {
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return err
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}
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return s.(*freezerController).Thaw(sp)
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}
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// OOMEventFD returns the memory cgroup's out of memory event fd that triggers
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// when processes inside the cgroup receive an oom event. Returns
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// ErrMemoryNotSupported if memory cgroups is not supported.
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func (c *cgroup) OOMEventFD() (uintptr, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return 0, c.err
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}
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s := c.getSubsystem(Memory)
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if s == nil {
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return 0, ErrMemoryNotSupported
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}
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sp, err := c.path(Memory)
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if err != nil {
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return 0, err
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}
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return s.(*memoryController).OOMEventFD(sp)
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}
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// State returns the state of the cgroup and its processes
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func (c *cgroup) State() State {
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c.mu.Lock()
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defer c.mu.Unlock()
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c.checkExists()
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if c.err != nil && c.err == ErrCgroupDeleted {
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return Deleted
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}
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s := c.getSubsystem(Freezer)
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if s == nil {
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return Thawed
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}
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sp, err := c.path(Freezer)
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if err != nil {
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return Unknown
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}
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state, err := s.(*freezerController).state(sp)
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if err != nil {
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return Unknown
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}
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return state
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}
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// MoveTo does a recursive move subsystem by subsystem of all the processes
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// inside the group
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func (c *cgroup) MoveTo(destination Cgroup) error {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.err != nil {
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return c.err
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}
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for _, s := range c.subsystems {
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processes, err := c.processes(s.Name(), true)
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if err != nil {
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return err
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}
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for _, p := range processes {
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if err := destination.Add(p); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func (c *cgroup) getSubsystem(n Name) Subsystem {
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for _, s := range c.subsystems {
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if s.Name() == n {
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return s
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}
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}
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return nil
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}
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func (c *cgroup) checkExists() {
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for _, s := range pathers(c.subsystems) {
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p, err := c.path(s.Name())
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if err != nil {
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return
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}
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if _, err := os.Lstat(s.Path(p)); err != nil {
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if os.IsNotExist(err) {
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c.err = ErrCgroupDeleted
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return
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}
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}
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}
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}
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