Do not convert blkio weight value using blkio->io conversion scheme

bfq weight controller (i.e. io.bfq.weight if present) is still using the same bfq weight scheme (i.e 1->1000, see [1].) Unfortunaly the documentation for this was wrong, and only fixed recently [2]. Therefore, if we map blkio weight to io.bfq.weight, there's no need to do any conversion. [1] https://github.com/torvalds/linux/blob/master/Documentation/block/bfq-iosched.rst [2] torvalds/linux@65752ae Signed-off-by: Daniel Dao <[email protected]>
opencontainers · Feb 3, 2021 · 29e782f · 29e782f
1 parent 7e3c3e8
commit 29e782f
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Showing 3 changed files with 1 addition and 26 deletions.
diff --git a/libcontainer/cgroups/fs2/io.go b/libcontainer/cgroups/fs2/io.go
@@ -29,7 +29,7 @@ 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(cgroups.ConvertBlkIOToCgroupV2Value(cgroup.Resources.BlkioWeight), 10)); err != nil {
+			strconv.FormatUint(uint64(cgroup.Resources.BlkioWeight), 10)); err != nil {
 			return err
 		}
 	}

diff --git a/libcontainer/cgroups/utils.go b/libcontainer/cgroups/utils.go
@@ -400,17 +400,6 @@ func WriteCgroupProc(dir string, pid int) error {
 	return err
 }
 
-// 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 {
-	if blkIoWeight == 0 {
-		return 0
-	}
-	return uint64(1 + (uint64(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)

diff --git a/libcontainer/cgroups/utils_test.go b/libcontainer/cgroups/utils_test.go
@@ -548,20 +548,6 @@ func TestGetHugePageSizeImpl(t *testing.T) {
 	}
 }
 
-func TestConvertBlkIOToCgroupV2Value(t *testing.T) {
-	cases := map[uint16]uint64{
-		0:    0,
-		10:   1,
-		1000: 10000,
-	}
-	for i, expected := range cases {
-		got := ConvertBlkIOToCgroupV2Value(i)
-		if got != expected {
-			t.Errorf("expected ConvertBlkIOToCgroupV2Value(%d) to be %d, got %d", i, expected, got)
-		}
-	}
-}
-
 func TestConvertCPUSharesToCgroupV2Value(t *testing.T) {
 	cases := map[uint64]uint64{
 		0:      0,