63 lines
2.1 KiB
Go
63 lines
2.1 KiB
Go
// +build linux,!nokmem
|
|
|
|
package fs
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"os"
|
|
"path/filepath"
|
|
"strconv"
|
|
"syscall" // for Errno type only
|
|
|
|
"github.com/opencontainers/runc/libcontainer/cgroups"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
const cgroupKernelMemoryLimit = "memory.kmem.limit_in_bytes"
|
|
|
|
func EnableKernelMemoryAccounting(path string) error {
|
|
// Ensure that kernel memory is available in this kernel build. If it
|
|
// isn't, we just ignore it because EnableKernelMemoryAccounting is
|
|
// automatically called for all memory limits.
|
|
if !cgroups.PathExists(filepath.Join(path, cgroupKernelMemoryLimit)) {
|
|
return nil
|
|
}
|
|
// 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)) {
|
|
// We have specifically been asked to set a kmem limit. If the kernel
|
|
// doesn't support it we *must* error out.
|
|
return errors.New("kernel memory accounting not supported by this kernel")
|
|
}
|
|
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 == unix.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
|
|
}
|