runc/cgroups/fs/cpuset.go

118 lines
2.7 KiB
Go

package fs
import (
"bytes"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"github.com/docker/libcontainer/cgroups"
)
type CpusetGroup struct {
}
func (s *CpusetGroup) Set(d *data) error {
dir, err := d.path("cpuset")
if err != nil {
return err
}
return s.SetDir(dir, d.c.CpusetCpus, d.pid)
}
func (s *CpusetGroup) Remove(d *data) error {
return removePath(d.path("cpuset"))
}
func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
return nil
}
func (s *CpusetGroup) SetDir(dir, value string, pid int) error {
if err := s.ensureParent(dir); 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 {
return err
}
// If we don't use --cpuset, the default cpuset.cpus is set in
// s.ensureParent, otherwise, use the value we set
if value != "" {
if err := writeFile(dir, "cpuset.cpus", value); 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 ensures that the parent directory of current is created
// with the proper cpus and mems files copied from it's parent if the values
// are a file with a new line char
func (s *CpusetGroup) ensureParent(current string) error {
parent := filepath.Dir(current)
if _, err := os.Stat(parent); err != nil {
if !os.IsNotExist(err) {
return err
}
if err := s.ensureParent(parent); err != nil {
return err
}
}
if err := os.MkdirAll(current, 0755); err != nil && !os.IsExist(err) {
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
}