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// +build linux
package fs
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/configs"
libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
)
type CpusetGroup struct {
}
func (s *CpusetGroup) Name() string {
return "cpuset"
}
func (s *CpusetGroup) Apply(d *cgroupData) error {
dir, err := d.path("cpuset")
if err != nil && !cgroups.IsNotFound(err) {
return err
}
return s.ApplyDir(dir, d.config, d.pid)
}
func (s *CpusetGroup) Set(path string, cgroup *configs.Cgroup) error {
if cgroup.Resources.CpusetCpus != "" {
if err := writeFile(path, "cpuset.cpus", cgroup.Resources.CpusetCpus); err != nil {
return err
}
}
if cgroup.Resources.CpusetMems != "" {
if err := writeFile(path, "cpuset.mems", cgroup.Resources.CpusetMems); err != nil {
return err
}
}
return nil
}
func (s *CpusetGroup) Remove(d *cgroupData) error {
return removePath(d.path("cpuset"))
}
func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
return nil
}
func (s *CpusetGroup) ApplyDir(dir string, cgroup *configs.Cgroup, pid int) error {
// This might happen if we have no cpuset cgroup mounted.
// Just do nothing and don't fail.
if dir == "" {
return nil
}
mountInfo, err := ioutil.ReadFile("/proc/self/mountinfo")
if err != nil {
return err
}
root := filepath.Dir(cgroups.GetClosestMountpointAncestor(dir, string(mountInfo)))
// 'ensureParent' start with parent because we don't want to
// explicitly inherit from parent, it could conflict with
// 'cpuset.cpu_exclusive'.
if err := s.ensureParent(filepath.Dir(dir), root); err != nil {
return err
}
if err := os.MkdirAll(dir, 0755); err != nil {
return err
}
// We didn't inherit cpuset configs from parent, but we have
// to ensure cpuset configs are set before moving task into the
// cgroup.
// The logic is, if user specified cpuset configs, use these
// specified configs, otherwise, inherit from parent. This makes
// cpuset configs work correctly with 'cpuset.cpu_exclusive', and
// keep backward compatbility.
if err := s.ensureCpusAndMems(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 := cgroups.WriteCgroupProc(dir, pid); err != nil {
return err
}
return nil
}
func (s *CpusetGroup) getSubsystemSettings(parent string) (cpus []byte, mems []byte, err error) {
if cpus, err = ioutil.ReadFile(filepath.Join(parent, "cpuset.cpus")); err != nil {
return
}
if mems, err = ioutil.ReadFile(filepath.Join(parent, "cpuset.mems")); err != nil {
return
}
return cpus, mems, nil
}
// ensureParent makes sure that the parent directory of current is created
// and populated with the proper cpus and mems files copied from
// it's parent.
func (s *CpusetGroup) ensureParent(current, root string) error {
parent := filepath.Dir(current)
if libcontainerUtils.CleanPath(parent) == root {
return nil
}
// Avoid infinite recursion.
if parent == current {
return fmt.Errorf("cpuset: cgroup parent path outside cgroup root")
}
if err := s.ensureParent(parent, root); err != nil {
return err
}
if err := os.MkdirAll(current, 0755); err != nil {
return err
}
return s.copyIfNeeded(current, parent)
}
// copyIfNeeded copies the cpuset.cpus and cpuset.mems from the parent
// directory to the current directory if the file's contents are 0
func (s *CpusetGroup) copyIfNeeded(current, parent string) error {
var (
err error
currentCpus, currentMems []byte
parentCpus, parentMems []byte
)
if currentCpus, currentMems, err = s.getSubsystemSettings(current); err != nil {
return err
}
if parentCpus, parentMems, err = s.getSubsystemSettings(parent); err != nil {
return err
}
if s.isEmpty(currentCpus) {
if err := writeFile(current, "cpuset.cpus", string(parentCpus)); err != nil {
return err
}
}
if s.isEmpty(currentMems) {
if err := writeFile(current, "cpuset.mems", string(parentMems)); err != nil {
return err
}
}
return nil
}
func (s *CpusetGroup) isEmpty(b []byte) bool {
return len(bytes.Trim(b, "\n")) == 0
}
func (s *CpusetGroup) ensureCpusAndMems(path string, cgroup *configs.Cgroup) error {
if err := s.Set(path, cgroup); err != nil {
return err
}
return s.copyIfNeeded(path, filepath.Dir(path))
}
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