deps: bump cgroups to v0.0.3, fix tests

For changelog, see https://github.com/opencontainers/cgroups/releases/tag/v0.0.3

This fixes two runc issues:

1. JSON incompatibility introduced in cgroups v0.0.2 (see
   https://github.com/opencontainers/cgroups/pull/22).

2. Bad CPU shares to CPU weight conversion (see
   https://github.com/opencontainers/runc/issues/4772).

Due to item 2, modify some tests accordingly.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

go.mod

@@ -14,7 +14,7 @@ require (
 	github.com/moby/sys/user v0.4.0
 	github.com/moby/sys/userns v0.1.0
 	github.com/mrunalp/fileutils v0.5.1
-	github.com/opencontainers/cgroups v0.0.2
+	github.com/opencontainers/cgroups v0.0.3
 	github.com/opencontainers/runtime-spec v1.2.2-0.20250401095657-e935f995dd67
 	github.com/opencontainers/selinux v1.12.0
 	github.com/seccomp/libseccomp-golang v0.11.0

go.sum

@@ -45,8 +45,8 @@ github.com/moby/sys/userns v0.1.0 h1:tVLXkFOxVu9A64/yh59slHVv9ahO9UIev4JZusOLG/g
 github.com/moby/sys/userns v0.1.0/go.mod h1:IHUYgu/kao6N8YZlp9Cf444ySSvCmDlmzUcYfDHOl28=
 github.com/mrunalp/fileutils v0.5.1 h1:F+S7ZlNKnrwHfSwdlgNSkKo67ReVf8o9fel6C3dkm/Q=
 github.com/mrunalp/fileutils v0.5.1/go.mod h1:M1WthSahJixYnrXQl/DFQuteStB1weuxD2QJNHXfbSQ=
-github.com/opencontainers/cgroups v0.0.2 h1:A+mAPPMfgKNCEZUUtibESFx06uvhAmvo8sSz3Abwk7o=
-github.com/opencontainers/cgroups v0.0.2/go.mod h1:s8lktyhlGUqM7OSRL5P7eAW6Wb+kWPNvt4qvVfzA5vs=
+github.com/opencontainers/cgroups v0.0.3 h1:Jc9dWh/0YLGjdy6J/9Ln8NM5BfTA4W2BY0GMozy3aDU=
+github.com/opencontainers/cgroups v0.0.3/go.mod h1:s8lktyhlGUqM7OSRL5P7eAW6Wb+kWPNvt4qvVfzA5vs=
 github.com/opencontainers/runtime-spec v1.2.2-0.20250401095657-e935f995dd67 h1:Q+KewUGTMamIe6Q39xCD/T1NC1POmaTlWnhjikCrZHA=
 github.com/opencontainers/runtime-spec v1.2.2-0.20250401095657-e935f995dd67/go.mod h1:jwyrGlmzljRJv/Fgzds9SsS/C5hL+LL3ko9hs6T5lQ0=
 github.com/opencontainers/selinux v1.12.0 h1:6n5JV4Cf+4y0KNXW48TLj5DwfXpvWlxXplUkdTrmPb8=

tests/integration/helpers.bash

@@ -352,7 +352,18 @@ function check_cpu_shares() {
 	local shares=$1
 
 	if [ -v CGROUP_V2 ]; then
-		local weight=$((1 + ((shares - 2) * 9999) / 262142))
+		# Same formula as ConvertCPUSharesToCgroupV2Value.
+		local weight
+		weight=$(awk -v shares="$shares" '
+		BEGIN {
+			if (shares == 0) { print 0; exit }
+			if (shares <= 2) { print 1; exit }
+			if (shares >= 262144) { print 10000; exit }
+			l = log(shares) / log(2)
+			exponent = (l*l + 125*l) / 612.0 - 7.0/34.0
+			print int(exp(exponent * log(10)) + 0.99)
+		}')
+
 		check_cpu_weight "$weight"
 	else
 		check_cgroup_value "cpu.shares" "$shares"

tests/integration/update.bats

@@ -545,10 +545,9 @@ EOF
 	runc run -d --console-socket "$CONSOLE_SOCKET" test_update
 	[ "$status" -eq 0 ]
 
-	# Check that initial values were properly set.
+	# Check that initial values (from setup) were properly set.
 	check_cpu_quota 500000 1000000
-	# Initial cpu shares of 100 corresponds to weight of 4.
-	check_cpu_weight 4
+	check_cpu_shares 100
 	check_systemd_value "TasksMax" 20
 
 	runc update -r - test_update <<EOF

vendor/github.com/opencontainers/cgroups/config_linux.go

@@ -29,7 +29,7 @@ type Cgroup struct {
 	ScopePrefix string `json:"scope_prefix,omitempty"`
 
 	// Resources contains various cgroups settings to apply.
-	*Resources `json:"Resources,omitempty"`
+	*Resources
 
 	// Systemd tells if systemd should be used to manage cgroups.
 	Systemd bool `json:"Systemd,omitempty"`

vendor/github.com/opencontainers/cgroups/utils.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"math"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -413,16 +414,30 @@ 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 cpuShares is y = (1 + ((x - 2) * 9999) / 262142)
-// convert from [2-262144] to [1-10000]
-// 262144 comes from Linux kernel definition "#define MAX_SHARES (1UL << 18)"
+// ConvertCPUSharesToCgroupV2Value converts CPU shares, used by cgroup v1,
+// to CPU weight, used by cgroup v2.
+//
+// Cgroup v1 CPU shares has a range of [2^1...2^18], i.e. [2...262144],
+// and the default value is 1024.
+//
+// Cgroup v2 CPU weight has a range of [10^0...10^4], i.e. [1...10000],
+// and the default value is 100.
 func ConvertCPUSharesToCgroupV2Value(cpuShares uint64) uint64 {
+	// The value of 0 means "unset".
 	if cpuShares == 0 {
 		return 0
 	}
-	return (1 + ((cpuShares-2)*9999)/262142)
+	if cpuShares <= 2 {
+		return 1
+	}
+	if cpuShares >= 262144 {
+		return 10000
+	}
+	l := math.Log2(float64(cpuShares))
+	// Quadratic function which fits min, max, and default.
+	exponent := (l*l+125*l)/612.0 - 7.0/34.0
+
+	return uint64(math.Ceil(math.Pow(10, exponent)))
 }
 
 // ConvertMemorySwapToCgroupV2Value converts MemorySwap value from OCI spec

vendor/modules.txt

@@ -51,7 +51,7 @@ github.com/moby/sys/userns
 # github.com/mrunalp/fileutils v0.5.1
 ## explicit; go 1.13
 github.com/mrunalp/fileutils
-# github.com/opencontainers/cgroups v0.0.2
+# github.com/opencontainers/cgroups v0.0.3
 ## explicit; go 1.23.0
 github.com/opencontainers/cgroups
 github.com/opencontainers/cgroups/devices