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package fs2
import (
"bufio"
"bytes"
"fmt"
"os"
"strconv"
"strings"
"github.com/sirupsen/logrus"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/configs"
)
func isIoSet(r *configs.Resources) bool {
return r.BlkioWeight != 0 ||
len(r.BlkioWeightDevice) > 0 ||
len(r.BlkioThrottleReadBpsDevice) > 0 ||
len(r.BlkioThrottleWriteBpsDevice) > 0 ||
len(r.BlkioThrottleReadIOPSDevice) > 0 ||
len(r.BlkioThrottleWriteIOPSDevice) > 0
}
// bfqDeviceWeightSupported checks for per-device BFQ weight support (added
// in kernel v5.4, commit 795fe54c2a8) by reading from "io.bfq.weight".
func bfqDeviceWeightSupported(bfq *os.File) bool {
if bfq == nil {
return false
}
_, _ = bfq.Seek(0, 0)
buf := make([]byte, 32)
_, _ = bfq.Read(buf)
// If only a single number (default weight) if read back, we have older kernel.
_, err := strconv.ParseInt(string(bytes.TrimSpace(buf)), 10, 64)
return err != nil
}
func setIo(dirPath string, r *configs.Resources) error {
if !isIoSet(r) {
return nil
}
// If BFQ IO scheduler is available, use it.
var bfq *os.File
if r.BlkioWeight != 0 || len(r.BlkioWeightDevice) > 0 {
var err error
bfq, err = cgroups.OpenFile(dirPath, "io.bfq.weight", os.O_RDWR)
if err == nil {
defer bfq.Close()
} else if !os.IsNotExist(err) {
return err
}
}
if r.BlkioWeight != 0 {
if bfq != nil { // Use BFQ.
if _, err := bfq.WriteString(strconv.FormatUint(uint64(r.BlkioWeight), 10)); err != nil {
return err
}
} else {
// Fallback to io.weight with a conversion scheme.
v := cgroups.ConvertBlkIOToIOWeightValue(r.BlkioWeight)
if err := cgroups.WriteFile(dirPath, "io.weight", strconv.FormatUint(v, 10)); err != nil {
return err
}
}
}
if bfqDeviceWeightSupported(bfq) {
for _, wd := range r.BlkioWeightDevice {
if _, err := bfq.WriteString(wd.WeightString() + "\n"); err != nil {
return fmt.Errorf("setting device weight %q: %w", wd.WeightString(), err)
}
}
}
for _, td := range r.BlkioThrottleReadBpsDevice {
if err := cgroups.WriteFile(dirPath, "io.max", td.StringName("rbps")); err != nil {
return err
}
}
for _, td := range r.BlkioThrottleWriteBpsDevice {
if err := cgroups.WriteFile(dirPath, "io.max", td.StringName("wbps")); err != nil {
return err
}
}
for _, td := range r.BlkioThrottleReadIOPSDevice {
if err := cgroups.WriteFile(dirPath, "io.max", td.StringName("riops")); err != nil {
return err
}
}
for _, td := range r.BlkioThrottleWriteIOPSDevice {
if err := cgroups.WriteFile(dirPath, "io.max", td.StringName("wiops")); err != nil {
return err
}
}
return nil
}
func readCgroup2MapFile(dirPath string, name string) (map[string][]string, error) {
ret := map[string][]string{}
f, err := cgroups.OpenFile(dirPath, name, os.O_RDONLY)
if err != nil {
return nil, err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
line := scanner.Text()
parts := strings.Fields(line)
if len(parts) < 2 {
continue
}
ret[parts[0]] = parts[1:]
}
if err := scanner.Err(); err != nil {
return nil, &parseError{Path: dirPath, File: name, Err: err}
}
return ret, nil
}
func statIo(dirPath string, stats *cgroups.Stats) error {
const file = "io.stat"
values, err := readCgroup2MapFile(dirPath, file)
if err != nil {
return err
}
// more details on the io.stat file format: https://www.kernel.org/doc/Documentation/cgroup-v2.txt
var parsedStats cgroups.BlkioStats
for k, v := range values {
d := strings.Split(k, ":")
if len(d) != 2 {
continue
}
major, err := strconv.ParseUint(d[0], 10, 64)
if err != nil {
return &parseError{Path: dirPath, File: file, Err: err}
}
minor, err := strconv.ParseUint(d[1], 10, 64)
if err != nil {
return &parseError{Path: dirPath, File: file, Err: err}
}
for _, item := range v {
d := strings.Split(item, "=")
if len(d) != 2 {
continue
}
op := d[0]
// Map to the cgroupv1 naming and layout (in separate tables).
var targetTable *[]cgroups.BlkioStatEntry
switch op {
// Equivalent to cgroupv1's blkio.io_service_bytes.
case "rbytes":
op = "Read"
targetTable = &parsedStats.IoServiceBytesRecursive
case "wbytes":
op = "Write"
targetTable = &parsedStats.IoServiceBytesRecursive
// Equivalent to cgroupv1's blkio.io_serviced.
case "rios":
op = "Read"
targetTable = &parsedStats.IoServicedRecursive
case "wios":
op = "Write"
targetTable = &parsedStats.IoServicedRecursive
default:
// Skip over entries we cannot map to cgroupv1 stats for now.
// In the future we should expand the stats struct to include
// them.
logrus.Debugf("cgroupv2 io stats: skipping over unmappable %s entry", item)
continue
}
value, err := strconv.ParseUint(d[1], 10, 64)
if err != nil {
return &parseError{Path: dirPath, File: file, Err: err}
}
entry := cgroups.BlkioStatEntry{
Op: op,
Major: major,
Minor: minor,
Value: value,
}
*targetTable = append(*targetTable, entry)
}
}
stats.BlkioStats = parsedStats
return nil
}
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