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moby--moby/pkg/cgroups/cgroups.go
Alexander Larsson 7f7d8419a7 cgroups: Splity out Apply/Cleanup to separate file/interface
This leaves only the generic cgroup helper functions in cgroups.go and
will allow easy implementations of other cgroup managers.

This also wires up the call to Cleanup the cgroup which was missing
before.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
2014-03-27 21:47:47 +01:00

91 lines
2.2 KiB
Go

package cgroups
import (
"bufio"
"fmt"
"github.com/dotcloud/docker/pkg/mount"
"io"
"io/ioutil"
"os"
"path/filepath"
"strings"
)
type Cgroup struct {
Name string `json:"name,omitempty"`
Parent string `json:"parent,omitempty"`
DeviceAccess bool `json:"device_access,omitempty"` // name of parent cgroup or slice
Memory int64 `json:"memory,omitempty"` // Memory limit (in bytes)
MemorySwap int64 `json:"memory_swap,omitempty"` // Total memory usage (memory + swap); set `-1' to disable swap
CpuShares int64 `json:"cpu_shares,omitempty"` // CPU shares (relative weight vs. other containers)
}
type ActiveCgroup interface {
Cleanup() error
}
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
func FindCgroupMountpoint(subsystem string) (string, error) {
mounts, err := mount.GetMounts()
if err != nil {
return "", err
}
for _, mount := range mounts {
if mount.Fstype == "cgroup" {
for _, opt := range strings.Split(mount.VfsOpts, ",") {
if opt == subsystem {
return mount.Mountpoint, nil
}
}
}
}
return "", fmt.Errorf("cgroup mountpoint not found for %s", subsystem)
}
// Returns the relative path to the cgroup docker is running in.
func GetThisCgroupDir(subsystem string) (string, error) {
f, err := os.Open("/proc/self/cgroup")
if err != nil {
return "", err
}
defer f.Close()
return parseCgroupFile(subsystem, f)
}
func GetInitCgroupDir(subsystem string) (string, error) {
f, err := os.Open("/proc/1/cgroup")
if err != nil {
return "", err
}
defer f.Close()
return parseCgroupFile(subsystem, f)
}
func parseCgroupFile(subsystem string, r io.Reader) (string, error) {
s := bufio.NewScanner(r)
for s.Scan() {
if err := s.Err(); err != nil {
return "", err
}
text := s.Text()
parts := strings.Split(text, ":")
for _, subs := range strings.Split(parts[1], ",") {
if subs == subsystem {
return parts[2], nil
}
}
}
return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", subsystem)
}
func writeFile(dir, file, data string) error {
return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
}
func (c *Cgroup) Apply(pid int) (ActiveCgroup, error) {
return rawApply(c, pid)
}