[chore]: Bump github.com/KimMachineGun/automemlimit from 0.4.0 to 0.5.0 (#2560)

vendor/github.com/KimMachineGun/automemlimit/memlimit/cgroups_linux.go

@@ -0,0 +1,98 @@
+//go:build linux
+// +build linux
+
+package memlimit
+
+import (
+	"math"
+	"os"
+	"path/filepath"
+
+	"github.com/containerd/cgroups/v3"
+	"github.com/containerd/cgroups/v3/cgroup1"
+	"github.com/containerd/cgroups/v3/cgroup2"
+)
+
+const (
+	cgroupMountPoint = "/sys/fs/cgroup"
+)
+
+// FromCgroup returns the memory limit based on the cgroups version on this system.
+func FromCgroup() (uint64, error) {
+	switch cgroups.Mode() {
+	case cgroups.Legacy:
+		return FromCgroupV1()
+	case cgroups.Hybrid:
+		return FromCgroupHybrid()
+	case cgroups.Unified:
+		return FromCgroupV2()
+	}
+	return 0, ErrNoCgroup
+}
+
+// FromCgroupV1 returns the memory limit from the cgroup v1.
+func FromCgroupV1() (uint64, error) {
+	cg, err := cgroup1.Load(cgroup1.RootPath, cgroup1.WithHiearchy(
+		cgroup1.SingleSubsystem(cgroup1.Default, cgroup1.Memory),
+	))
+	if err != nil {
+		return 0, err
+	}
+
+	metrics, err := cg.Stat(cgroup1.IgnoreNotExist)
+	if err != nil {
+		return 0, err
+	}
+
+	if limit := metrics.GetMemory().GetHierarchicalMemoryLimit(); limit != 0 && limit != getCgroupV1NoLimit() {
+		return limit, nil
+	}
+
+	return 0, ErrNoLimit
+}
+
+func getCgroupV1NoLimit() uint64 {
+	ps := uint64(os.Getpagesize())
+	return math.MaxInt64 / ps * ps
+}
+
+// FromCgroupHybrid returns the memory limit from the cgroup v1 or v2.
+// It checks the cgroup v2 first, and if it fails, it falls back to cgroup v1.
+func FromCgroupHybrid() (uint64, error) {
+	limit, err := fromCgroupV2(filepath.Join(cgroupMountPoint, "unified"))
+	if err == nil {
+		return limit, nil
+	} else if err != ErrNoLimit {
+		return 0, err
+	}
+
+	return FromCgroupV1()
+}
+
+// FromCgroupV2 returns the memory limit from the cgroup v2.
+func FromCgroupV2() (uint64, error) {
+	return fromCgroupV2(cgroupMountPoint)
+}
+
+func fromCgroupV2(mountPoint string) (uint64, error) {
+	path, err := cgroup2.NestedGroupPath("")
+	if err != nil {
+		return 0, err
+	}
+
+	m, err := cgroup2.Load(path, cgroup2.WithMountpoint(mountPoint))
+	if err != nil {
+		return 0, err
+	}
+
+	stats, err := m.Stat()
+	if err != nil {
+		return 0, err
+	}
+
+	if limit := stats.GetMemory().GetUsageLimit(); limit != 0 && limit != math.MaxUint64 {
+		return limit, nil
+	}
+
+	return 0, ErrNoLimit
+}