cgroupfs

Documentation

Overview

Package cgroupfs implements cgroupfs.

A cgroup is a collection of tasks on the system, organized into a tree-like structure similar to a filesystem directory tree. In fact, each cgroup is represented by a directory on cgroupfs, and is manipulated through control files in the directory.

All cgroups on a system are organized into hierarchies. Hierarchies are a distinct tree of cgroups, with a common set of controllers. One or more cgroupfs mounts may point to each hierarchy. These mounts provide a common view into the same tree of cgroups.

A controller (also known as a "resource controller", or a cgroup "subsystem") determines the behaviour of each cgroup.

In addition to cgroupfs, the kernel has a cgroup registry that tracks system-wide state related to cgroups such as active hierarchies and the controllers associated with them.

Since cgroupfs doesn't allow hardlinks, there is a unique mapping between cgroupfs dentries and inodes.

Synchronization

Cgroup hierarchy creation and destruction is protected by the kernel.CgroupRegistry.mu. Once created, a hierarchy's set of controllers, the filesystem associated with it, and the root cgroup for the hierarchy are immutable.

Membership of tasks within cgroups is protected by cgroupfs.filesystem.tasksMu. Tasks also maintain a set of all cgroups they're in, and this list is protected by Task.mu.

Lock order:

kernel.CgroupRegistry.mu

cgroupfs.filesystem.mu
  Task.mu
    cgroupfs.filesystem.tasksMu.

Index

• Constants
• Variables
• type FilesystemType
  • func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, ...) (*vfs.Filesystem, *vfs.Dentry, error)
  • func (FilesystemType) Name() string
  • func (FilesystemType) Release(ctx context.Context)
  • func (fsType *FilesystemType) StateFields() []string
  • func (fsType *FilesystemType) StateLoad(stateSourceObject state.Source)
  • func (fsType *FilesystemType) StateSave(stateSinkObject state.Sink)
  • func (fsType *FilesystemType) StateTypeName() string
• type InternalData
  • func (i *InternalData) StateFields() []string
  • func (i *InternalData) StateLoad(stateSourceObject state.Source)
  • func (i *InternalData) StateSave(stateSinkObject state.Sink)
  • func (i *InternalData) StateTypeName() string

Constants

const (
	// Name is the default filesystem name.
	Name = "cgroup"
)

Variables

var SupportedMountOptions = []string{"all", "cpu", "cpuacct", "cpuset", "job", "memory"}

SupportedMountOptions is the set of supported mount options for cgroupfs.

Types

type FilesystemType

type FilesystemType struct{}

FilesystemType implements vfs.FilesystemType.

+stateify savable

func (FilesystemType) GetFilesystem

func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error)

GetFilesystem implements vfs.FilesystemType.GetFilesystem.

func (FilesystemType) Name

func (FilesystemType) Name() string

Name implements vfs.FilesystemType.Name.

func (FilesystemType) Release

func (FilesystemType) Release(ctx context.Context)

Release implements vfs.FilesystemType.Release.

func (*FilesystemType) StateFields

func (fsType *FilesystemType) StateFields() []string

func (*FilesystemType) StateLoad

func (fsType *FilesystemType) StateLoad(stateSourceObject state.Source)

+checklocksignore

func (*FilesystemType) StateSave

func (fsType *FilesystemType) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*FilesystemType) StateTypeName

func (fsType *FilesystemType) StateTypeName() string

type InternalData

type InternalData struct {
	DefaultControlValues map[string]int64
}

InternalData contains internal data passed in to the cgroupfs mount via vfs.GetFilesystemOptions.InternalData.

+stateify savable

func (*InternalData) StateFields

func (i *InternalData) StateFields() []string

func (*InternalData) StateLoad

func (i *InternalData) StateLoad(stateSourceObject state.Source)

+checklocksignore

func (*InternalData) StateSave

func (i *InternalData) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*InternalData) StateTypeName

func (i *InternalData) StateTypeName() string