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|
package cgroups
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"path/filepath"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
func NewCputset(root string) *cpusetController {
return &cpusetController{
root: filepath.Join(root, string(Cpuset)),
}
}
type cpusetController struct {
root string
}
func (c *cpusetController) Name() Name {
return Cpuset
}
func (c *cpusetController) Path(path string) string {
return filepath.Join(c.root, path)
}
func (c *cpusetController) Create(path string, resources *specs.LinuxResources) error {
if err := c.ensureParent(c.Path(path), c.root); err != nil {
return err
}
if err := os.MkdirAll(c.Path(path), defaultDirPerm); err != nil {
return err
}
if err := c.copyIfNeeded(c.Path(path), filepath.Dir(c.Path(path))); err != nil {
return err
}
if resources.CPU != nil {
for _, t := range []struct {
name string
value *string
}{
{
name: "cpus",
value: &resources.CPU.Cpus,
},
{
name: "mems",
value: &resources.CPU.Mems,
},
} {
if t.value != nil {
if err := ioutil.WriteFile(
filepath.Join(c.Path(path), fmt.Sprintf("cpuset.%s", t.name)),
[]byte(*t.value),
defaultFilePerm,
); err != nil {
return err
}
}
}
}
return nil
}
func (c *cpusetController) getValues(path string) (cpus []byte, mems []byte, err error) {
if cpus, err = ioutil.ReadFile(filepath.Join(path, "cpuset.cpus")); err != nil && !os.IsNotExist(err) {
return
}
if mems, err = ioutil.ReadFile(filepath.Join(path, "cpuset.mems")); err != nil && !os.IsNotExist(err) {
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 (c *cpusetController) ensureParent(current, root string) error {
parent := filepath.Dir(current)
if _, err := filepath.Rel(root, parent); err != nil {
return nil
}
// Avoid infinite recursion.
if parent == current {
return fmt.Errorf("cpuset: cgroup parent path outside cgroup root")
}
if cleanPath(parent) != root {
if err := c.ensureParent(parent, root); err != nil {
return err
}
}
if err := os.MkdirAll(current, defaultDirPerm); err != nil {
return err
}
return c.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 (c *cpusetController) copyIfNeeded(current, parent string) error {
var (
err error
currentCpus, currentMems []byte
parentCpus, parentMems []byte
)
if currentCpus, currentMems, err = c.getValues(current); err != nil {
return err
}
if parentCpus, parentMems, err = c.getValues(parent); err != nil {
return err
}
if isEmpty(currentCpus) {
if err := ioutil.WriteFile(
filepath.Join(current, "cpuset.cpus"),
parentCpus,
defaultFilePerm,
); err != nil {
return err
}
}
if isEmpty(currentMems) {
if err := ioutil.WriteFile(
filepath.Join(current, "cpuset.mems"),
parentMems,
defaultFilePerm,
); err != nil {
return err
}
}
return nil
}
func isEmpty(b []byte) bool {
return len(bytes.Trim(b, "\n")) == 0
}
|
