Merge pull request #2212 from Zyqsempai/2211-convert-blkio-weight-properly

Convert blkioWeight to io.weight properly

Author: AkihiroSuda

libcontainer/cgroups/fs2/io.go

@@ -17,11 +17,11 @@ import (
 func setIo(dirPath string, cgroup *configs.Cgroup) error {
 	if cgroup.Resources.BlkioWeight != 0 {
 		filename := "io.bfq.weight"
-		if err := fscommon.WriteFile(dirPath, filename, strconv.FormatUint(uint64(cgroup.Resources.BlkioWeight), 10)); err != nil {
+		if err := fscommon.WriteFile(dirPath, filename,
+			strconv.FormatUint(cgroups.ConvertBlkIOToCgroupV2Value(cgroup.Resources.BlkioWeight), 10)); err != nil {
 			return err
 		}
 	}
-
 	for _, td := range cgroup.Resources.BlkioThrottleReadBpsDevice {
 		if err := fscommon.WriteFile(dirPath, "io.max", td.StringName("rbps")); err != nil {
 			return err

libcontainer/cgroups/utils.go

@@ -587,6 +587,14 @@ func isEINVAL(err error) bool {
 	}
 }
 
+// Since the OCI spec is designed for cgroup v1, in some cases
+// there is need to convert from the cgroup v1 configuration to cgroup v2
+// the formula for BlkIOWeight is y = (1 + (x - 10) * 9999 / 990)
+// convert linearly from [10-1000] to [1-10000]
+func ConvertBlkIOToCgroupV2Value(blkIoWeight uint16) uint64 {
+	return uint64(1 + (blkIoWeight-10)*9999/990)
+}
+
 // Since the OCI spec is designed for cgroup v1, in some cases
 // there is need to convert from the cgroup v1 configuration to cgroup v2
 // the formula for cpuShares is y = (1 + ((x - 2) * 9999) / 262142)