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