blob: 2a3ccf0085ac98d8dd3f089ab8435ce5d074db1a [file] [log] [blame]
// +build linux
package fs
import (
"bufio"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/configs"
)
const cgroupKernelMemoryLimit = "memory.kmem.limit_in_bytes"
type MemoryGroup struct {
}
func (s *MemoryGroup) Name() string {
return "memory"
}
func (s *MemoryGroup) Apply(d *cgroupData) (err error) {
path, err := d.path("memory")
if err != nil && !cgroups.IsNotFound(err) {
return err
}
if memoryAssigned(d.config) {
if path != "" {
if err := os.MkdirAll(path, 0755); err != nil {
return err
}
}
if d.config.KernelMemory != 0 {
if err := EnableKernelMemoryAccounting(path); err != nil {
return err
}
}
}
defer func() {
if err != nil {
os.RemoveAll(path)
}
}()
// We need to join memory cgroup after set memory limits, because
// kmem.limit_in_bytes can only be set when the cgroup is empty.
_, err = d.join("memory")
if err != nil && !cgroups.IsNotFound(err) {
return err
}
return nil
}
func EnableKernelMemoryAccounting(path string) error {
// Check if kernel memory is enabled
// We have to limit the kernel memory here as it won't be accounted at all
// until a limit is set on the cgroup and limit cannot be set once the
// cgroup has children, or if there are already tasks in the cgroup.
for _, i := range []int64{1, -1} {
if err := setKernelMemory(path, i); err != nil {
return err
}
}
return nil
}
func setKernelMemory(path string, kernelMemoryLimit int64) error {
if path == "" {
return fmt.Errorf("no such directory for %s", cgroupKernelMemoryLimit)
}
if !cgroups.PathExists(filepath.Join(path, cgroupKernelMemoryLimit)) {
// kernel memory is not enabled on the system so we should do nothing
return nil
}
if err := ioutil.WriteFile(filepath.Join(path, cgroupKernelMemoryLimit), []byte(strconv.FormatInt(kernelMemoryLimit, 10)), 0700); err != nil {
// Check if the error number returned by the syscall is "EBUSY"
// The EBUSY signal is returned on attempts to write to the
// memory.kmem.limit_in_bytes file if the cgroup has children or
// once tasks have been attached to the cgroup
if pathErr, ok := err.(*os.PathError); ok {
if errNo, ok := pathErr.Err.(syscall.Errno); ok {
if errNo == syscall.EBUSY {
return fmt.Errorf("failed to set %s, because either tasks have already joined this cgroup or it has children", cgroupKernelMemoryLimit)
}
}
}
return fmt.Errorf("failed to write %v to %v: %v", kernelMemoryLimit, cgroupKernelMemoryLimit, err)
}
return nil
}
func setMemoryAndSwap(path string, cgroup *configs.Cgroup) error {
// When memory and swap memory are both set, we need to handle the cases
// for updating container.
if cgroup.Resources.Memory != 0 && cgroup.Resources.MemorySwap > 0 {
memoryUsage, err := getMemoryData(path, "")
if err != nil {
return err
}
// When update memory limit, we should adapt the write sequence
// for memory and swap memory, so it won't fail because the new
// value and the old value don't fit kernel's validation.
if memoryUsage.Limit < uint64(cgroup.Resources.MemorySwap) {
if err := writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(cgroup.Resources.MemorySwap, 10)); err != nil {
return err
}
if err := writeFile(path, "memory.limit_in_bytes", strconv.FormatInt(cgroup.Resources.Memory, 10)); err != nil {
return err
}
} else {
if err := writeFile(path, "memory.limit_in_bytes", strconv.FormatInt(cgroup.Resources.Memory, 10)); err != nil {
return err
}
if err := writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(cgroup.Resources.MemorySwap, 10)); err != nil {
return err
}
}
} else {
if cgroup.Resources.Memory != 0 {
if err := writeFile(path, "memory.limit_in_bytes", strconv.FormatInt(cgroup.Resources.Memory, 10)); err != nil {
return err
}
}
if cgroup.Resources.MemorySwap > 0 {
if err := writeFile(path, "memory.memsw.limit_in_bytes", strconv.FormatInt(cgroup.Resources.MemorySwap, 10)); err != nil {
return err
}
}
}
return nil
}
func (s *MemoryGroup) Set(path string, cgroup *configs.Cgroup) error {
if err := setMemoryAndSwap(path, cgroup); err != nil {
return err
}
if cgroup.Resources.KernelMemory != 0 {
if err := setKernelMemory(path, cgroup.Resources.KernelMemory); err != nil {
return err
}
}
if cgroup.Resources.MemoryReservation != 0 {
if err := writeFile(path, "memory.soft_limit_in_bytes", strconv.FormatInt(cgroup.Resources.MemoryReservation, 10)); err != nil {
return err
}
}
if cgroup.Resources.KernelMemoryTCP != 0 {
if err := writeFile(path, "memory.kmem.tcp.limit_in_bytes", strconv.FormatInt(cgroup.Resources.KernelMemoryTCP, 10)); err != nil {
return err
}
}
if cgroup.Resources.OomKillDisable {
if err := writeFile(path, "memory.oom_control", "1"); err != nil {
return err
}
}
if cgroup.Resources.MemorySwappiness == nil || int64(*cgroup.Resources.MemorySwappiness) == -1 {
return nil
} else if int64(*cgroup.Resources.MemorySwappiness) >= 0 && int64(*cgroup.Resources.MemorySwappiness) <= 100 {
if err := writeFile(path, "memory.swappiness", strconv.FormatInt(*cgroup.Resources.MemorySwappiness, 10)); err != nil {
return err
}
} else {
return fmt.Errorf("invalid value:%d. valid memory swappiness range is 0-100", int64(*cgroup.Resources.MemorySwappiness))
}
return nil
}
func (s *MemoryGroup) Remove(d *cgroupData) error {
return removePath(d.path("memory"))
}
func (s *MemoryGroup) GetStats(path string, stats *cgroups.Stats) error {
// Set stats from memory.stat.
statsFile, err := os.Open(filepath.Join(path, "memory.stat"))
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
defer statsFile.Close()
sc := bufio.NewScanner(statsFile)
for sc.Scan() {
t, v, err := getCgroupParamKeyValue(sc.Text())
if err != nil {
return fmt.Errorf("failed to parse memory.stat (%q) - %v", sc.Text(), err)
}
stats.MemoryStats.Stats[t] = v
}
stats.MemoryStats.Cache = stats.MemoryStats.Stats["cache"]
memoryUsage, err := getMemoryData(path, "")
if err != nil {
return err
}
stats.MemoryStats.Usage = memoryUsage
swapUsage, err := getMemoryData(path, "memsw")
if err != nil {
return err
}
stats.MemoryStats.SwapUsage = swapUsage
kernelUsage, err := getMemoryData(path, "kmem")
if err != nil {
return err
}
stats.MemoryStats.KernelUsage = kernelUsage
kernelTCPUsage, err := getMemoryData(path, "kmem.tcp")
if err != nil {
return err
}
stats.MemoryStats.KernelTCPUsage = kernelTCPUsage
return nil
}
func memoryAssigned(cgroup *configs.Cgroup) bool {
return cgroup.Resources.Memory != 0 ||
cgroup.Resources.MemoryReservation != 0 ||
cgroup.Resources.MemorySwap > 0 ||
cgroup.Resources.KernelMemory > 0 ||
cgroup.Resources.KernelMemoryTCP > 0 ||
cgroup.Resources.OomKillDisable ||
(cgroup.Resources.MemorySwappiness != nil && *cgroup.Resources.MemorySwappiness != -1)
}
func getMemoryData(path, name string) (cgroups.MemoryData, error) {
memoryData := cgroups.MemoryData{}
moduleName := "memory"
if name != "" {
moduleName = strings.Join([]string{"memory", name}, ".")
}
usage := strings.Join([]string{moduleName, "usage_in_bytes"}, ".")
maxUsage := strings.Join([]string{moduleName, "max_usage_in_bytes"}, ".")
failcnt := strings.Join([]string{moduleName, "failcnt"}, ".")
limit := strings.Join([]string{moduleName, "limit_in_bytes"}, ".")
value, err := getCgroupParamUint(path, usage)
if err != nil {
if moduleName != "memory" && os.IsNotExist(err) {
return cgroups.MemoryData{}, nil
}
return cgroups.MemoryData{}, fmt.Errorf("failed to parse %s - %v", usage, err)
}
memoryData.Usage = value
value, err = getCgroupParamUint(path, maxUsage)
if err != nil {
if moduleName != "memory" && os.IsNotExist(err) {
return cgroups.MemoryData{}, nil
}
return cgroups.MemoryData{}, fmt.Errorf("failed to parse %s - %v", maxUsage, err)
}
memoryData.MaxUsage = value
value, err = getCgroupParamUint(path, failcnt)
if err != nil {
if moduleName != "memory" && os.IsNotExist(err) {
return cgroups.MemoryData{}, nil
}
return cgroups.MemoryData{}, fmt.Errorf("failed to parse %s - %v", failcnt, err)
}
memoryData.Failcnt = value
value, err = getCgroupParamUint(path, limit)
if err != nil {
if moduleName != "memory" && os.IsNotExist(err) {
return cgroups.MemoryData{}, nil
}
return cgroups.MemoryData{}, fmt.Errorf("failed to parse %s - %v", limit, err)
}
memoryData.Limit = value
return memoryData, nil
}