package gc

import "github.com/containerd/containerd/gc"

Package gc experiments with providing central gc tooling to ensure deterministic resource removal within containerd.

For now, we just have a single exported implementation that can be used under certain use cases.

Index ¶

• func ConcurrentMark(ctx context.Context, root <-chan Node, refs func(context.Context, Node, func(Node)) error) (map[Node]struct{}, error)
• func Sweep(reachable map[Node]struct{}, all []Node, remove func(Node) error) error
• func Tricolor(roots []Node, refs func(ref Node) ([]Node, error)) (map[Node]struct{}, error)
• type Node
• type ResourceType
• type Stats

Functions ¶

func ConcurrentMark ¶

func ConcurrentMark(ctx context.Context, root <-chan Node, refs func(context.Context, Node, func(Node)) error) (map[Node]struct{}, error)

ConcurrentMark implements simple, concurrent GC. All the roots are scanned and the complete set of references is formed by calling the refs function for each seen object. This function returns a map of all object reachable from a root.

Correct usage requires that the caller not allow the arguments to change until the result is used to delete objects in the system.

It will allocate memory proportional to the size of the reachable set.

func Sweep ¶

func Sweep(reachable map[Node]struct{}, all []Node, remove func(Node) error) error

Sweep removes all nodes returned through the channel which are not in the reachable set by calling the provided remove function.

func Tricolor ¶

func Tricolor(roots []Node, refs func(ref Node) ([]Node, error)) (map[Node]struct{}, error)

Tricolor implements basic, single-thread tri-color GC. Given the roots, the complete set and a refs function, this function returns a map of all reachable objects.

Correct usage requires that the caller not allow the arguments to change until the result is used to delete objects in the system.

It will allocate memory proportional to the size of the reachable set.

We can probably use this to inform a design for incremental GC by injecting callbacks to the set modification algorithms.

Types ¶

type Node ¶

type Node struct {
	Type      ResourceType
	Namespace string
	Key       string
}

Node presents a resource which has a type and key, this node can be used to lookup other nodes.

type ResourceType ¶

type ResourceType uint8

ResourceType represents type of resource at a node

type Stats ¶

type Stats interface {
	Elapsed() time.Duration
}

Stats about a garbage collection run

Source Files ¶

gc.go

Directories ¶