docker-runc关闭kmem

 0// +build linux,nokmem
 1
 2package fs
 3
 4func EnableKernelMemoryAccounting(path string) error {
 5	return nil
 6}
 7
 8func setKernelMemory(path string, kernelMemoryLimit int64) error {
 9	return nil
10}

 0// +build linux,!nokmem
 1
 2package fs
 3
 4import (
 5	"fmt"
 6	"io/ioutil"
 7	"os"
 8	"path/filepath"
 9	"strconv"
10	"syscall" // for Errno type only
11
12	"github.com/opencontainers/runc/libcontainer/cgroups"
13	"golang.org/x/sys/unix"
14)
15
16const cgroupKernelMemoryLimit = "memory.kmem.limit_in_bytes"
17
18func EnableKernelMemoryAccounting(path string) error {
19	// Check if kernel memory is enabled
20	// We have to limit the kernel memory here as it won't be accounted at all
21	// until a limit is set on the cgroup and limit cannot be set once the
22	// cgroup has children, or if there are already tasks in the cgroup.
23	for _, i := range []int64{1, -1} {
24		if err := setKernelMemory(path, i); err != nil {
25			return err
26		}
27	}
28	return nil
29}
30
31func setKernelMemory(path string, kernelMemoryLimit int64) error {
32	if path == "" {
33		return fmt.Errorf("no such directory for %s", cgroupKernelMemoryLimit)
34	}
35	if !cgroups.PathExists(filepath.Join(path, cgroupKernelMemoryLimit)) {
36		// kernel memory is not enabled on the system so we should do nothing
37		return nil
38	}
39	if err := ioutil.WriteFile(filepath.Join(path, cgroupKernelMemoryLimit), []byte(strconv.FormatInt(kernelMemoryLimit, 10)), 0700); err != nil {
40		// Check if the error number returned by the syscall is "EBUSY"
41		// The EBUSY signal is returned on attempts to write to the
42		// memory.kmem.limit_in_bytes file if the cgroup has children or
43		// once tasks have been attached to the cgroup
44		if pathErr, ok := err.(*os.PathError); ok {
45			if errNo, ok := pathErr.Err.(syscall.Errno); ok {
46				if errNo == unix.EBUSY {
47					return fmt.Errorf("failed to set %s, because either tasks have already joined this cgroup or it has children", cgroupKernelMemoryLimit)
48				}
49			}
50		}
51		return fmt.Errorf("failed to write %v to %v: %v", kernelMemoryLimit, cgroupKernelMemoryLimit, err)
52	}
53	return nil
54}