Update containerd/cgroups repo fix perf issue

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

vendor/github.com/containerd/cgroups/blkio.go

@@ -3,12 +3,12 @@ package cgroups
 import (
 	"bufio"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
-	"syscall"
 
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
@@ -56,8 +56,8 @@ func (b *blkioController) Update(path string, resources *specs.LinuxResources) e
 	return b.Create(path, resources)
 }
 
-func (b *blkioController) Stat(path string, stats *Stats) error {
-	stats.Blkio = &BlkioStat{}
+func (b *blkioController) Stat(path string, stats *Metrics) error {
+	stats.Blkio = &BlkIOStat{}
 	settings := []blkioStatSettings{
 		{
 			name:  "throttle.io_serviced",
@@ -105,8 +105,13 @@ func (b *blkioController) Stat(path string, stats *Stats) error {
 			},
 		)
 	}
+	f, err := os.Open("/proc/diskstats")
+	if err != nil {
+		return err
+	}
+	defer f.Close()
 
-	devices, err := getDevices("/dev")
+	devices, err := getDevices(f)
 	if err != nil {
 		return err
 	}
@@ -119,7 +124,7 @@ func (b *blkioController) Stat(path string, stats *Stats) error {
 	return nil
 }
 
-func (b *blkioController) readEntry(devices map[deviceKey]string, path, name string, entry *[]BlkioEntry) error {
+func (b *blkioController) readEntry(devices map[deviceKey]string, path, name string, entry *[]*BlkIOEntry) error {
 	f, err := os.Open(filepath.Join(b.Path(path), fmt.Sprintf("blkio.%s", name)))
 	if err != nil {
 		return err
@@ -131,7 +136,7 @@ func (b *blkioController) readEntry(devices map[deviceKey]string, path, name str
 			return err
 		}
 		// format: dev type amount
-		fields := strings.FieldsFunc(sc.Text(), splitBlkioStatLine)
+		fields := strings.FieldsFunc(sc.Text(), splitBlkIOStatLine)
 		if len(fields) < 3 {
 			if len(fields) == 2 && fields[0] == "Total" {
 				// skip total line
@@ -158,7 +163,7 @@ func (b *blkioController) readEntry(devices map[deviceKey]string, path, name str
 		if err != nil {
 			return err
 		}
-		*entry = append(*entry, BlkioEntry{
+		*entry = append(*entry, &BlkIOEntry{
 			Device: devices[deviceKey{major, minor}],
 			Major:  major,
 			Minor:  minor,
@@ -235,7 +240,7 @@ type blkioSettings struct {
 
 type blkioStatSettings struct {
 	name  string
-	entry *[]BlkioEntry
+	entry *[]*BlkIOEntry
 }
 
 func uintf(v interface{}) []byte {
@@ -257,7 +262,7 @@ func throttleddev(v interface{}) []byte {
 	return []byte(fmt.Sprintf("%d:%d %d", td.Major, td.Minor, td.Rate))
 }
 
-func splitBlkioStatLine(r rune) bool {
+func splitBlkIOStatLine(r rune) bool {
 	return r == ' ' || r == ':'
 }
 
@@ -268,50 +273,32 @@ type deviceKey struct {
 // getDevices makes a best effort attempt to read all the devices into a map
 // keyed by major and minor number. Since devices may be mapped multiple times,
 // we err on taking the first occurrence.
-func getDevices(path string) (map[deviceKey]string, error) {
-	// TODO(stevvooe): We are ignoring lots of errors. It might be kind of
-	// challenging to debug this if we aren't mapping devices correctly.
-	// Consider logging these errors.
-	devices := map[deviceKey]string{}
-	if err := filepath.Walk(path, func(p string, fi os.FileInfo, err error) error {
+func getDevices(r io.Reader) (map[deviceKey]string, error) {
+
+	var (
+		s       = bufio.NewScanner(r)
+		devices = make(map[deviceKey]string)
+	)
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		major, err := strconv.Atoi(fields[0])
 		if err != nil {
-			return err
+			return nil, err
 		}
-		switch {
-		case fi.IsDir():
-			switch fi.Name() {
-			case "pts", "shm", "fd", "mqueue", ".lxc", ".lxd-mounts":
-				return filepath.SkipDir
-			default:
-				return nil
-			}
-		case fi.Name() == "console":
-			return nil
-		default:
-			if fi.Mode()&os.ModeDevice == 0 {
-				// skip non-devices
-				return nil
-			}
-
-			st, ok := fi.Sys().(*syscall.Stat_t)
-			if !ok {
-				return fmt.Errorf("%s: unable to convert to system stat", p)
-			}
-
-			key := deviceKey{major(st.Rdev), minor(st.Rdev)}
-			if _, ok := devices[key]; ok {
-				return nil // skip it if we have already populated the path.
-			}
-
-			devices[key] = p
+		minor, err := strconv.Atoi(fields[1])
+		if err != nil {
+			return nil, err
 		}
-
-		return nil
-	}); err != nil {
-		return nil, err
+		key := deviceKey{
+			major: uint64(major),
+			minor: uint64(minor),
+		}
+		if _, ok := devices[key]; ok {
+			continue
+		}
+		devices[key] = filepath.Join("/dev", fields[2])
 	}
-
-	return devices, nil
+	return devices, s.Err()
 }
 
 func major(devNumber uint64) uint64 {