diff --git a/linux/list.go b/linux/list.go
deleted file mode 100644
index 0b436f0c5..000000000
--- a/linux/list.go
+++ /dev/null
@@ -1,75 +0,0 @@
-// +build linux
-
-package linux
-
-import (
-	"context"
-	"sync"
-
-	"github.com/containerd/containerd/namespaces"
-)
-
-func newTaskList() *taskList {
-	return &taskList{
-		tasks: make(map[string]map[string]*Task),
-	}
-}
-
-type taskList struct {
-	mu    sync.Mutex
-	tasks map[string]map[string]*Task
-}
-
-func (l *taskList) get(ctx context.Context, id string) (*Task, error) {
-	l.mu.Lock()
-	defer l.mu.Unlock()
-	namespace, err := namespaces.NamespaceRequired(ctx)
-	if err != nil {
-		return nil, err
-	}
-	tasks, ok := l.tasks[namespace]
-	if !ok {
-		return nil, ErrTaskNotExists
-	}
-	t, ok := tasks[id]
-	if !ok {
-		return nil, ErrTaskNotExists
-	}
-	return t, nil
-}
-
-func (l *taskList) add(ctx context.Context, t *Task) error {
-	namespace, err := namespaces.NamespaceRequired(ctx)
-	if err != nil {
-		return err
-	}
-	return l.addWithNamespace(namespace, t)
-}
-
-func (l *taskList) addWithNamespace(namespace string, t *Task) error {
-	l.mu.Lock()
-	defer l.mu.Unlock()
-
-	id := t.id
-	if _, ok := l.tasks[namespace]; !ok {
-		l.tasks[namespace] = make(map[string]*Task)
-	}
-	if _, ok := l.tasks[namespace][id]; ok {
-		return ErrTaskAlreadyExists
-	}
-	l.tasks[namespace][id] = t
-	return nil
-}
-
-func (l *taskList) delete(ctx context.Context, t *Task) {
-	l.mu.Lock()
-	defer l.mu.Unlock()
-	namespace, err := namespaces.NamespaceRequired(ctx)
-	if err != nil {
-		return
-	}
-	tasks, ok := l.tasks[namespace]
-	if ok {
-		delete(tasks, t.id)
-	}
-}
diff --git a/linux/runtime.go b/linux/runtime.go
index 4a7147e6e..cdc6f4af8 100644
--- a/linux/runtime.go
+++ b/linux/runtime.go
@@ -29,10 +29,8 @@ import (
 )
 
 var (
-	ErrTaskNotExists     = errors.New("task does not exist")
-	ErrTaskAlreadyExists = errors.New("task already exists")
-	pluginID             = fmt.Sprintf("%s.%s", plugin.RuntimePlugin, "linux")
-	empty                = &google_protobuf.Empty{}
+	pluginID = fmt.Sprintf("%s.%s", plugin.RuntimePlugin, "linux")
+	empty    = &google_protobuf.Empty{}
 )
 
 const (
@@ -90,7 +88,7 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 		shimDebug: cfg.ShimDebug,
 		runtime:   cfg.Runtime,
 		monitor:   monitor.(runtime.TaskMonitor),
-		tasks:     newTaskList(),
+		tasks:     runtime.NewTaskList(),
 		db:        m.(*bolt.DB),
 		address:   ic.Address,
 	}
@@ -99,7 +97,7 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 		return nil, err
 	}
 	for _, t := range tasks {
-		if err := r.tasks.addWithNamespace(t.namespace, t); err != nil {
+		if err := r.tasks.AddWithNamespace(t.namespace, t); err != nil {
 			return nil, err
 		}
 	}
@@ -115,7 +113,7 @@ type Runtime struct {
 	address   string
 
 	monitor runtime.TaskMonitor
-	tasks   *taskList
+	tasks   *runtime.TaskList
 	db      *bolt.DB
 }
 
@@ -175,7 +173,7 @@ func (r *Runtime) Create(ctx context.Context, id string, opts runtime.CreateOpts
 		return nil, errors.New(grpc.ErrorDesc(err))
 	}
 	t := newTask(id, namespace, s)
-	if err := r.tasks.add(ctx, t); err != nil {
+	if err := r.tasks.Add(ctx, t); err != nil {
 		return nil, err
 	}
 	// after the task is created, add it to the monitor
@@ -204,7 +202,7 @@ func (r *Runtime) Delete(ctx context.Context, c runtime.Task) (*runtime.Exit, er
 	if err := lc.shim.KillShim(ctx); err != nil {
 		log.G(ctx).WithError(err).Error("failed to kill shim")
 	}
-	r.tasks.delete(ctx, lc)
+	r.tasks.Delete(ctx, lc)
 
 	bundle := loadBundle(filepath.Join(r.root, namespace, lc.id), namespace)
 	if err := bundle.Delete(); err != nil {
@@ -218,19 +216,7 @@ func (r *Runtime) Delete(ctx context.Context, c runtime.Task) (*runtime.Exit, er
 }
 
 func (r *Runtime) Tasks(ctx context.Context) ([]runtime.Task, error) {
-	namespace, err := namespaces.NamespaceRequired(ctx)
-	if err != nil {
-		return nil, err
-	}
-	var o []runtime.Task
-	tasks, ok := r.tasks.tasks[namespace]
-	if !ok {
-		return o, nil
-	}
-	for _, t := range tasks {
-		o = append(o, t)
-	}
-	return o, nil
+	return r.tasks.GetAll(ctx)
 }
 
 func (r *Runtime) restoreTasks(ctx context.Context) ([]*Task, error) {
@@ -255,7 +241,7 @@ func (r *Runtime) restoreTasks(ctx context.Context) ([]*Task, error) {
 }
 
 func (r *Runtime) Get(ctx context.Context, id string) (runtime.Task, error) {
-	return r.tasks.get(ctx, id)
+	return r.tasks.Get(ctx, id)
 }
 
 func (r *Runtime) loadTasks(ctx context.Context, ns string) ([]*Task, error) {
diff --git a/runtime/task_list.go b/runtime/task_list.go
new file mode 100644
index 000000000..e5d5c0e53
--- /dev/null
+++ b/runtime/task_list.go
@@ -0,0 +1,95 @@
+package runtime
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"github.com/containerd/containerd/namespaces"
+)
+
+var (
+	ErrTaskNotExists     = errors.New("task does not exist")
+	ErrTaskAlreadyExists = errors.New("task already exists")
+)
+
+func NewTaskList() *TaskList {
+	return &TaskList{
+		tasks: make(map[string]map[string]Task),
+	}
+}
+
+type TaskList struct {
+	mu    sync.Mutex
+	tasks map[string]map[string]Task
+}
+
+func (l *TaskList) Get(ctx context.Context, id string) (Task, error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	namespace, err := namespaces.NamespaceRequired(ctx)
+	if err != nil {
+		return nil, err
+	}
+	tasks, ok := l.tasks[namespace]
+	if !ok {
+		return nil, ErrTaskNotExists
+	}
+	t, ok := tasks[id]
+	if !ok {
+		return nil, ErrTaskNotExists
+	}
+	return t, nil
+}
+
+func (l *TaskList) GetAll(ctx context.Context) ([]Task, error) {
+	namespace, err := namespaces.NamespaceRequired(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var o []Task
+	tasks, ok := l.tasks[namespace]
+	if !ok {
+		return o, nil
+	}
+	for _, t := range tasks {
+		o = append(o, t)
+	}
+	return o, nil
+}
+
+func (l *TaskList) Add(ctx context.Context, t Task) error {
+	namespace, err := namespaces.NamespaceRequired(ctx)
+	if err != nil {
+		return err
+	}
+	return l.AddWithNamespace(namespace, t)
+}
+
+func (l *TaskList) AddWithNamespace(namespace string, t Task) error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	id := t.ID()
+	if _, ok := l.tasks[namespace]; !ok {
+		l.tasks[namespace] = make(map[string]Task)
+	}
+	if _, ok := l.tasks[namespace][id]; ok {
+		return ErrTaskAlreadyExists
+	}
+	l.tasks[namespace][id] = t
+	return nil
+}
+
+func (l *TaskList) Delete(ctx context.Context, t Task) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	namespace, err := namespaces.NamespaceRequired(ctx)
+	if err != nil {
+		return
+	}
+	tasks, ok := l.tasks[namespace]
+	if ok {
+		delete(tasks, t.ID())
+	}
+}