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|
package cgroups
import (
"bufio"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
"golang.org/x/sys/unix"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
func NewMemory(root string) *memoryController {
return &memoryController{
root: filepath.Join(root, string(Memory)),
}
}
type memoryController struct {
root string
}
func (m *memoryController) Name() Name {
return Memory
}
func (m *memoryController) Path(path string) string {
return filepath.Join(m.root, path)
}
func (m *memoryController) Create(path string, resources *specs.LinuxResources) error {
if err := os.MkdirAll(m.Path(path), defaultDirPerm); err != nil {
return err
}
if resources.Memory == nil {
return nil
}
if resources.Memory.Kernel != nil {
// 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 := ioutil.WriteFile(
filepath.Join(m.Path(path), "memory.kmem.limit_in_bytes"),
[]byte(strconv.FormatInt(i, 10)),
defaultFilePerm,
); err != nil {
return checkEBUSY(err)
}
}
}
return m.set(path, getMemorySettings(resources))
}
func (m *memoryController) Update(path string, resources *specs.LinuxResources) error {
if resources.Memory == nil {
return nil
}
g := func(v *int64) bool {
return v != nil && *v > 0
}
settings := getMemorySettings(resources)
if g(resources.Memory.Limit) && g(resources.Memory.Swap) {
// if the updated swap value is larger than the current memory limit set the swap changes first
// then set the memory limit as swap must always be larger than the current limit
current, err := readUint(filepath.Join(m.Path(path), "memory.limit_in_bytes"))
if err != nil {
return err
}
if current < uint64(*resources.Memory.Swap) {
settings[0], settings[1] = settings[1], settings[0]
}
}
return m.set(path, settings)
}
func (m *memoryController) Stat(path string, stats *Stats) error {
f, err := os.Open(filepath.Join(m.Path(path), "memory.stat"))
if err != nil {
return err
}
defer f.Close()
stats.Memory = &MemoryStat{}
if err := m.parseStats(f, stats.Memory); err != nil {
return err
}
for _, t := range []struct {
module string
entry *MemoryEntry
}{
{
module: "",
entry: &stats.Memory.Usage,
},
{
module: "memsw",
entry: &stats.Memory.Swap,
},
{
module: "kmem",
entry: &stats.Memory.Kernel,
},
{
module: "kmem.tcp",
entry: &stats.Memory.KernelTCP,
},
} {
for _, tt := range []struct {
name string
value *uint64
}{
{
name: "usage_in_bytes",
value: &t.entry.Usage,
},
{
name: "max_usage_in_bytes",
value: &t.entry.Max,
},
{
name: "failcnt",
value: &t.entry.Failcnt,
},
{
name: "limit_in_bytes",
value: &t.entry.Limit,
},
} {
parts := []string{"memory"}
if t.module != "" {
parts = append(parts, t.module)
}
parts = append(parts, tt.name)
v, err := readUint(filepath.Join(m.Path(path), strings.Join(parts, ".")))
if err != nil {
return err
}
*tt.value = v
}
}
return nil
}
func (m *memoryController) OOMEventFD(path string) (uintptr, error) {
root := m.Path(path)
f, err := os.Open(filepath.Join(root, "memory.oom_control"))
if err != nil {
return 0, err
}
defer f.Close()
fd, _, serr := unix.RawSyscall(unix.SYS_EVENTFD2, 0, unix.FD_CLOEXEC, 0)
if serr != 0 {
return 0, serr
}
if err := writeEventFD(root, f.Fd(), fd); err != nil {
unix.Close(int(fd))
return 0, err
}
return fd, nil
}
func writeEventFD(root string, cfd, efd uintptr) error {
f, err := os.OpenFile(filepath.Join(root, "cgroup.event_control"), os.O_WRONLY, 0)
if err != nil {
return err
}
_, err = f.WriteString(fmt.Sprintf("%d %d", efd, cfd))
f.Close()
return err
}
func (m *memoryController) parseStats(r io.Reader, stat *MemoryStat) error {
var (
raw = make(map[string]uint64)
sc = bufio.NewScanner(r)
line int
)
for sc.Scan() {
if err := sc.Err(); err != nil {
return err
}
key, v, err := parseKV(sc.Text())
if err != nil {
return fmt.Errorf("%d: %v", line, err)
}
raw[key] = v
line++
}
stat.Cache = raw["cache"]
stat.RSS = raw["rss"]
stat.RSSHuge = raw["rss_huge"]
stat.MappedFile = raw["mapped_file"]
stat.Dirty = raw["dirty"]
stat.Writeback = raw["writeback"]
stat.PgPgIn = raw["pgpgin"]
stat.PgPgOut = raw["pgpgout"]
stat.PgFault = raw["pgfault"]
stat.PgMajFault = raw["pgmajfault"]
stat.InactiveAnon = raw["inactive_anon"]
stat.ActiveAnon = raw["active_anon"]
stat.InactiveFile = raw["inactive_file"]
stat.ActiveFile = raw["active_file"]
stat.Unevictable = raw["unevictable"]
stat.HierarchicalMemoryLimit = raw["hierarchical_memory_limit"]
stat.HierarchicalSwapLimit = raw["hierarchical_memsw_limit"]
stat.TotalCache = raw["total_cache"]
stat.TotalRSS = raw["total_rss"]
stat.TotalRSSHuge = raw["total_rss_huge"]
stat.TotalMappedFile = raw["total_mapped_file"]
stat.TotalDirty = raw["total_dirty"]
stat.TotalWriteback = raw["total_writeback"]
stat.TotalPgPgIn = raw["total_pgpgin"]
stat.TotalPgPgOut = raw["total_pgpgout"]
stat.TotalPgFault = raw["total_pgfault"]
stat.TotalPgMajFault = raw["total_pgmajfault"]
stat.TotalInactiveAnon = raw["total_inactive_anon"]
stat.TotalActiveAnon = raw["total_active_anon"]
stat.TotalInactiveFile = raw["total_inactive_file"]
stat.TotalActiveFile = raw["total_active_file"]
stat.TotalUnevictable = raw["total_unevictable"]
return nil
}
func (m *memoryController) set(path string, settings []memorySettings) error {
for _, t := range settings {
if t.value != nil {
if err := ioutil.WriteFile(
filepath.Join(m.Path(path), fmt.Sprintf("memory.%s", t.name)),
[]byte(strconv.FormatInt(*t.value, 10)),
defaultFilePerm,
); err != nil {
return err
}
}
}
return nil
}
type memorySettings struct {
name string
value *int64
}
func getMemorySettings(resources *specs.LinuxResources) []memorySettings {
mem := resources.Memory
var swappiness *int64
if mem.Swappiness != nil {
v := int64(*mem.Swappiness)
swappiness = &v
}
return []memorySettings{
{
name: "limit_in_bytes",
value: mem.Limit,
},
{
name: "memsw.limit_in_bytes",
value: mem.Swap,
},
{
name: "kmem.limit_in_bytes",
value: mem.Kernel,
},
{
name: "kmem.tcp.limit_in_bytes",
value: mem.KernelTCP,
},
{
name: "oom_control",
value: getOomControlValue(mem),
},
{
name: "swappiness",
value: swappiness,
},
}
}
func checkEBUSY(err error) error {
if pathErr, ok := err.(*os.PathError); ok {
if errNo, ok := pathErr.Err.(syscall.Errno); ok {
if errNo == unix.EBUSY {
return fmt.Errorf(
"failed to set memory.kmem.limit_in_bytes, because either tasks have already joined this cgroup or it has children")
}
}
}
return err
}
func getOomControlValue(mem *specs.LinuxMemory) *int64 {
if mem.DisableOOMKiller != nil && *mem.DisableOOMKiller {
i := int64(1)
return &i
}
return nil
}
|
