cgroup

Documentation

Index

• Constants
• func Subsys(name string, executor executor.Executor, timeout time.Duration) (bool, error)
• func SubsysMounts(executor executor.Executor, timeout time.Duration) (map[string]string, error)
• func SubsysPath(name string, executor executor.Executor, timeout time.Duration) (string, error)
• type ByPathLength
  • func (b ByPathLength) Len() int
  • func (b ByPathLength) Less(i, j int) bool
  • func (b ByPathLength) Swap(i int, j int)
• type CPUSet
  • func NewCPUSet(path string, cpus, mems isolation.IntSet, cpuExclusive, memExclusive bool) (CPUSet, error)
  • func NewCPUSetWithExecutor(path string, cpus isolation.IntSet, mems isolation.IntSet, cpuExclusive bool, ...) (CPUSet, error)
• type Cgroup
  • func NewCgroup(controllers []string, path string) (Cgroup, error)
  • func NewCgroupWithExecutor(controllers []string, path string, executor executor.Executor, ...) (Cgroup, error)
• type Filesystem
• type Metadata

Constants

const (
	// CPUSetController is the canonical name of the cgroups cpuset controller.
	CPUSetController = "cpuset"

	// CPUController is the canonical name of the cgroups cpu controller.
	CPUController = "cpu"

	// MemoryController is the canonical name of the cgroups memory controller.
	MemoryController = "memory"

	// DefaultCommandTimeout is the default amount of time to wait for
	// dispatched commands to finish executing.
	DefaultCommandTimeout = 10 * time.Second
)

const (
	// CPUSetMems is the name of the memory node attribute for a cpuset.
	CPUSetMems = "cpuset.mems"

	// CPUSetCpus is the name of the cpus attribute for a cpuset.
	CPUSetCpus = "cpuset.cpus"

	// CPUSetCPUExclusive is the name of the exclusive cpu attribute
	// for a cpuset.
	CPUSetCPUExclusive = "cpuset.cpu_exclusive"

	// CPUSetMemExclusive is the name of the exclusive memory node attribute
	// for a cpuset.
	CPUSetMemExclusive = "cpuset.mem_exclusive"
)

Functions

func Subsys

func Subsys(name string, executor executor.Executor, timeout time.Duration) (bool, error)

Subsys returns true if the named subsystem is mounted.

func SubsysMounts

func SubsysMounts(executor executor.Executor, timeout time.Duration) (map[string]string, error)

SubsysMounts returns a map of cgroup subsystem controller names to mount points in the file system.

func SubsysPath

func SubsysPath(name string, executor executor.Executor, timeout time.Duration) (string, error)

SubsysPath returns the absolute path where the supplied subsystem is mounted. Returns the empty string if the subsystem is not mounted.

Types

type ByPathLength

type ByPathLength []Cgroup

ByPathLength implements sort.Interface for []Cgroup. We define a partial order on Cgroups based on path length. For a slice of Cgroups in an ancestry chain this yields a topological sort beginning with the root of the Cgroup hierarchy.

func (ByPathLength) Len

func (b ByPathLength) Len() int

Len returns the length of the Cgroup slice. This method satisfies part of sort.Interface.

func (ByPathLength) Less

func (b ByPathLength) Less(i, j int) bool

Less returns true if the Cgroup at index i has a shorter path than the Cgroup at index j.. This method satisfies part of sort.Interface.

func (ByPathLength) Swap

func (b ByPathLength) Swap(i int, j int)

Swap swaps two elements in the Cgroup slice. This method satisfies part of sort.Interface.

type CPUSet

type CPUSet interface {
	isolation.Isolation

	// Cgroup returns the underlying cgroup for this CPUSet.
	Cgroup() Cgroup

	// Cpus returns the set of cpus allocated to this CPUSet.
	Cpus() isolation.IntSet

	// Cpus returns the set of memory nodes allocated to this CPUSet.
	Mems() isolation.IntSet

	// CPUExclusive returns true if this CPUSet's cpus are allocated
	// exclusively..
	CPUExclusive() bool

	// MemExclusive returns true if this CPUSet's memory nodes are allocated
	// exclusively..
	MemExclusive() bool
}

CPUSet represents a cgroup in the cpuset hierarchy.

func NewCPUSet

func NewCPUSet(path string, cpus, mems isolation.IntSet, cpuExclusive, memExclusive bool) (CPUSet, error)

NewCPUSet creates a new CPUSet with the default (local) executor and default timeout.

func NewCPUSetWithExecutor

func NewCPUSetWithExecutor(path string,
	cpus isolation.IntSet,
	mems isolation.IntSet,
	cpuExclusive bool,
	memExclusive bool,
	executor executor.Executor,
	timeout time.Duration) (CPUSet, error)

NewCPUSetWithExecutor creates a new CPUSet with the supplied executor and timeout.

type Cgroup

type Cgroup interface {
	isolation.Isolation
	Metadata
	Filesystem
}

Cgroup represents a Linux control group. See https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt

Usage of this interface requires the libcgroup tools to be installed on the system. This library interacts with cgroups by shelling out to utility programs like `cgcreate`, `cgexec`, `cgget` and friends.

func NewCgroup

func NewCgroup(controllers []string, path string) (Cgroup, error)

NewCgroup returns a new Cgroup with the supplied controllers and path. Returns an error if no controllers are specified or the path is empty.

func NewCgroupWithExecutor

func NewCgroupWithExecutor(controllers []string,
	path string,
	executor executor.Executor,
	cmdTimeout time.Duration) (Cgroup, error)

NewCgroupWithExecutor returns a new Cgroup with the supplied controllers, path and executor. Returns an error if no controllers are specified or the path is empty.

type Filesystem

type Filesystem interface {
	// AbsPath returns the absolute path to this cgroup within the
	// VFS mount for the specified controller.
	// Returns the empty string if the controller is not a member of
	// this cgroup's controllers.
	// e.g. `d, err := cgroup.AbsPath("cpuset")`
	AbsPath(controller string) string

	// Exists returns `true` iff this cgroup is present in all of its
	// controller hierarchies.
	Exists() (bool, error)

	// Destroy removes this cgroup.
	// If recursive is specified, also destroy this cgroup's children.
	// Returns an error if this cgroup has children but recurvisve was not
	// specified.
	// Returns an error if this cgroup cannot be destroyed.
	Destroy(recursive bool) error

	// Tasks returns the pids for this cgroup and the supplied controller.
	// Returns an error if the controller is not a member of
	// this cgroup's controllers.
	//
	// NB: Linux pid range is [0,  2^22]; see /proc/sys/kernel/pid_max.
	Tasks(controller string) (isolation.IntSet, error)

	// Get returns the value of an attribute for this Cgroup.
	Get(name string) (string, error)

	// Set overwrites the value of an attribute for this Cgroup.
	Set(name string, value string) error

	// SetAndCheck overwrites the value of an attribute for this Cgroup and
	// returns an error if a subsequent read of the same attribute does
	// not exactly match the written value.
	SetAndCheck(name string, value string) error
}

Filesystem represents Linux control group's backing virtual file system. These methods shell out to external libcgroup-tools programs.

type Metadata

type Metadata interface {
	// Controllers returns this cgroup's controllers.
	Controllers() []string

	// Path returns this cgroup's path in the hierarchy.
	Path() string

	// IsRoot returns true if this cgroup is the root of the hierarchy.
	IsRoot() bool

	// Parent returns the direct ancestor of this cgroup, or nil if this
	// is the root.
	Parent() Cgroup

	// Ancestors returns all ancestors of this cgroup, in depth order
	// beginning with the root of the hierarchy. The result does not
	// contain this cgroup.
	Ancestors() []Cgroup

	// Spec returns an identifier compatible with libcgroup-tools.
	// Returns a string like 'cpu,cpuset:/my/cool/group'.
	Spec() string
}

Metadata represents a Linux control group's metadata. These methods do not shell out to external libcgroup-tools programs.