cgroups

Documentation

Overview

Package cgroups provides utilities to access Linux control group (CGroups) parameters (total memory, for example) for a given process. The original implementation is taken from https://github.com/uber-go/automaxprocs

Index

• func IsCGroupV2() (bool, error)
• func MemoryQuotaV2() (int64, bool, error)
• type CGroup
  • func NewCGroup(path string) *CGroup
  • func (cg *CGroup) ParamPath(param string) string
  • func (cg *CGroup) Path() string
• type CGroupSubsys
  • func NewCGroupSubsysFromLine(line string) (*CGroupSubsys, error)
• type CGroups
  • func NewCGroups(procPathMountInfo, procPathCGroup string) (CGroups, error)
  • func NewCGroupsForCurrentProcess() (CGroups, error)
  • func (cg CGroups) MemoryQuota() (int64, bool, error)
• type MountPoint
  • func NewMountPointFromLine(line string) (*MountPoint, error)
  • func (mp *MountPoint) Translate(absPath string) (string, error)

Functions

func IsCGroupV2

func IsCGroupV2() (bool, error)

IsCGroupV2 returns true if the system supports and uses cgroup2. It gets the required information for deciding from mountinfo file.

func MemoryQuotaV2

func MemoryQuotaV2() (int64, bool, error)

MemoryQuotaV2 returns the total memory limit of the process It is a result of cgroupv2 `memory.max`. If the value of `memory.max` was not set (max), the method returns `(-1, false, nil)`.

Types

type CGroup

type CGroup struct {
	// contains filtered or unexported fields
}

CGroup represents the data structure for a Linux control group.

func NewCGroup

func NewCGroup(path string) *CGroup

NewCGroup returns a new *CGroup from a given path.

func (*CGroup) ParamPath

func (cg *CGroup) ParamPath(param string) string

ParamPath returns the path of the given cgroup param under itself.

func (*CGroup) Path

func (cg *CGroup) Path() string

Path returns the path of the CGroup*.

type CGroupSubsys

type CGroupSubsys struct {
	ID         int
	Subsystems []string
	Name       string
}

CGroupSubsys represents the data structure for entities in `/proc/$PID/cgroup`. See also proc(5) for more information.

func NewCGroupSubsysFromLine

func NewCGroupSubsysFromLine(line string) (*CGroupSubsys, error)

NewCGroupSubsysFromLine returns a new *CGroupSubsys by parsing a string in the format of `/proc/$PID/cgroup`

type CGroups

type CGroups map[string]*CGroup

CGroups is a map that associates each CGroup with its subsystem name.

func NewCGroups

func NewCGroups(procPathMountInfo, procPathCGroup string) (CGroups, error)

NewCGroups returns a new *CGroups from given `mountinfo` and `cgroup` files under for some process under `/proc` file system (see also proc(5) for more information).

func NewCGroupsForCurrentProcess

func NewCGroupsForCurrentProcess() (CGroups, error)

NewCGroupsForCurrentProcess returns a new *CGroups instance for the current process.

func (CGroups) MemoryQuota

func (cg CGroups) MemoryQuota() (int64, bool, error)

MemoryQuota returns the total memory limit of the process It is a result of `memory.limit_in_bytes`. If the value of `memory.limit_in_bytes` was not set (-1) or (9223372036854771712), the method returns `(-1, false, nil)`.

type MountPoint

type MountPoint struct {
	MountID        int
	ParentID       int
	DeviceID       string
	Root           string
	MountPoint     string
	Options        []string
	OptionalFields []string
	FSType         string
	MountSource    string
	SuperOptions   []string
}

MountPoint is the data structure for the mount points in `/proc/$PID/mountinfo`. See also proc(5) for more information.

func NewMountPointFromLine

func NewMountPointFromLine(line string) (*MountPoint, error)

NewMountPointFromLine parses a line read from `/proc/$PID/mountinfo` and returns a new *MountPoint.

func (*MountPoint) Translate

func (mp *MountPoint) Translate(absPath string) (string, error)

Translate converts an absolute path inside the *MountPoint's file system to the host file system path in the mount namespace the *MountPoint belongs to.