memory manager: provide the skeleton for the memory manager

Provide memory manager struct and methods that should be implemented.

Signed-off-by: Artyom Lukianov <alukiano@redhat.com>

pkg/kubelet/cm/memorymanager/memory_manager.go

@@ -0,0 +1,151 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package memorymanager
+
+import (
+	"sync"
+	"time"
+
+	cadvisorapi "github.com/google/cadvisor/info/v1"
+
+	v1 "k8s.io/api/core/v1"
+	runtimeapi "k8s.io/cri-api/pkg/apis/runtime/v1alpha2"
+	"k8s.io/kubernetes/pkg/kubelet/cm/containermap"
+	"k8s.io/kubernetes/pkg/kubelet/cm/memorymanager/state"
+	"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager"
+	"k8s.io/kubernetes/pkg/kubelet/config"
+	"k8s.io/kubernetes/pkg/kubelet/status"
+)
+
+// memoryManagerStateFileName is the file name where memory manager stores its state
+const memoryManagerStateFileName = "memory_manager_state"
+
+// ActivePodsFunc is a function that returns a list of pods to reconcile.
+type ActivePodsFunc func() []*v1.Pod
+
+type runtimeService interface {
+	UpdateContainerResources(id string, resources *runtimeapi.LinuxContainerResources) error
+}
+
+type sourcesReadyStub struct{}
+
+func (s *sourcesReadyStub) AddSource(source string) {}
+func (s *sourcesReadyStub) AllReady() bool          { return true }
+
+// Manager interface provides methods for Kubelet to manage pod memory.
+type Manager interface {
+	// Start is called during Kubelet initialization.
+	Start(activePods ActivePodsFunc, sourcesReady config.SourcesReady, podStatusProvider status.PodStatusProvider, containerRuntime runtimeService, initialContainers containermap.ContainerMap) error
+
+	// AddContainer is called between container create and container start
+	// so that initial memory affinity settings can be written through to the
+	// container runtime before the first process begins to execute.
+	AddContainer(p *v1.Pod, c *v1.Container, containerID string) error
+
+	// Allocate is called to pre-allocate memory resources during Pod admission.
+	// This must be called at some point prior to the AddContainer() call for a container, e.g. at pod admission time.
+	Allocate(pod *v1.Pod, container *v1.Container) error
+
+	// RemoveContainer is called after Kubelet decides to kill or delete a
+	// container. After this call, the memory manager stops trying to reconcile
+	// that container, and any memory allocated to the container are freed.
+	RemoveContainer(containerID string) error
+
+	// State returns a read-only interface to the internal memory manager state.
+	State() state.Reader
+
+	// GetTopologyHints implements the topologymanager.HintProvider Interface
+	// and is consulted to achieve NUMA aware resource alignment among this
+	// and other resource controllers.
+	GetTopologyHints(*v1.Pod, *v1.Container) map[string][]topologymanager.TopologyHint
+
+	// GetPodTopologyHints implements the topologymanager.HintProvider Interface
+	// and is consulted to achieve NUMA aware resource alignment among this
+	// and other resource controllers.
+	GetPodTopologyHints(*v1.Pod) map[string][]topologymanager.TopologyHint
+}
+
+type manager struct {
+	sync.Mutex
+	policy Policy
+
+	// state allows to restore information regarding memory allocation for guaranteed pods
+	// in the case of the kubelet restart
+	state state.State
+
+	// containerRuntime is the container runtime service interface needed
+	// to make UpdateContainerResources() calls against the containers.
+	containerRuntime runtimeService
+
+	// activePods is a method for listing active pods on the node
+	// so all the containers can be updated in the reconciliation loop.
+	activePods ActivePodsFunc
+
+	// podStatusProvider provides a method for obtaining pod statuses
+	// and the containerID of their containers
+	podStatusProvider status.PodStatusProvider
+
+	// containerMap provides a mapping from (pod, container) -> containerID
+	// for all containers a pod
+	containerMap containermap.ContainerMap
+
+	nodeAllocatableReservation v1.ResourceList
+
+	// sourcesReady provides the readiness of kubelet configuration sources such as apiserver update readiness.
+	// We use it to determine when we can purge inactive pods from checkpointed state.
+	sourcesReady config.SourcesReady
+
+	// stateFileDirectory holds the directory where the state file for checkpoints is held.
+	stateFileDirectory string
+}
+
+var _ Manager = &manager{}
+
+// NewManager returns new instance of the memory manager
+func NewManager(reconcilePeriod time.Duration, machineInfo *cadvisorapi.MachineInfo, nodeAllocatableReservation v1.ResourceList, stateFileDirectory string, affinity topologymanager.Store) (Manager, error) {
+
+}
+
+// Start starts the memory manager reconcile loop under the kubelet to keep state updated
+func (m *manager) Start(activePods ActivePodsFunc, sourcesReady config.SourcesReady, podStatusProvider status.PodStatusProvider, containerRuntime runtimeService, initialContainers containermap.ContainerMap) error {
+
+}
+
+// AddContainer saves the value of requested memory for the guranteed pod under the state and set memory affinity according to the topolgy manager
+func (m *manager) AddContainer(p *v1.Pod, c *v1.Container, containerID string) error {
+
+}
+
+// Allocate is called to pre-allocate memory resources during Pod admission.
+func (m *manager) Allocate(pod *v1.Pod, container *v1.Container) error {
+
+}
+
+// RemoveContainer removes the container from the state
+func (m *manager) RemoveContainer(containerID string) error {
+
+}
+
+// State returns the state of the manager
+func (m *manager) State() state.Reader {
+	return m.state
+}
+
+// GetTopologyHints returns the topology hints for the topology manager
+func (m *manager) GetTopologyHints(pod *v1.Pod, container *v1.Container) map[string][]topologymanager.TopologyHint {
+
+}