/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.flink.runtime.instance;
import org.apache.flink.runtime.clusterframework.types.ResourceProfile;
import org.apache.flink.runtime.executiongraph.Execution;
import org.apache.flink.api.common.JobID;
import org.apache.flink.runtime.jobmanager.scheduler.Locality;
import org.apache.flink.runtime.jobmanager.slots.AllocatedSlot;
import org.apache.flink.runtime.jobmanager.slots.SlotOwner;
import org.apache.flink.runtime.jobmanager.slots.TaskManagerGateway;
import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
import org.apache.flink.util.AbstractID;
import javax.annotation.Nullable;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
/**
* A SimpleSlot represents a single slot on a TaskManager instance, or a slot within a shared slot.
*
* <p>If this slot is part of a {@link SharedSlot}, then the parent attribute will point to that shared slot.
* If not, then the parent attribute is null.
*/
public class SimpleSlot extends Slot {
/** The updater used to atomically swap in the execution */
private static final AtomicReferenceFieldUpdater<SimpleSlot, Execution> VERTEX_UPDATER =
AtomicReferenceFieldUpdater.newUpdater(SimpleSlot.class, Execution.class, "executedTask");
// ------------------------------------------------------------------------
/** Task being executed in the slot. Volatile to force a memory barrier and allow for correct double-checking */
private volatile Execution executedTask;
/** The locality attached to the slot, defining whether the slot was allocated at the desired location. */
private volatile Locality locality = Locality.UNCONSTRAINED;
// ------------------------------------------------------------------------
// Old Constructors (prior FLIP-6)
// ------------------------------------------------------------------------
/**
* Creates a new simple slot that stands alone and does not belong to shared slot.
*
* @param jobID The ID of the job that the slot is allocated for.
* @param owner The component from which this slot is allocated.
* @param location The location info of the TaskManager where the slot was allocated from
* @param slotNumber The number of the task slot on the instance.
* @param taskManagerGateway The gateway to communicate with the TaskManager of this slot
*/
public SimpleSlot(
JobID jobID, SlotOwner owner, TaskManagerLocation location, int slotNumber,
TaskManagerGateway taskManagerGateway) {
this(jobID, owner, location, slotNumber, taskManagerGateway, null, null);
}
/**
* Creates a new simple slot that belongs to the given shared slot and
* is identified by the given ID.
*
* @param jobID The ID of the job that the slot is allocated for.
* @param owner The component from which this slot is allocated.
* @param location The location info of the TaskManager where the slot was allocated from
* @param slotNumber The number of the simple slot in its parent shared slot.
* @param taskManagerGateway to communicate with the associated task manager.
* @param parent The parent shared slot.
* @param groupID The ID that identifies the group that the slot belongs to.
*/
public SimpleSlot(
JobID jobID, SlotOwner owner, TaskManagerLocation location, int slotNumber,
TaskManagerGateway taskManagerGateway,
@Nullable SharedSlot parent, @Nullable AbstractID groupID) {
super(parent != null ?
parent.getAllocatedSlot() :
new AllocatedSlot(NO_ALLOCATION_ID, jobID, location, slotNumber,
ResourceProfile.UNKNOWN, taskManagerGateway),
owner, slotNumber, parent, groupID);
}
// ------------------------------------------------------------------------
// Constructors
// ------------------------------------------------------------------------
/**
* Creates a new simple slot that stands alone and does not belong to shared slot.
*
* @param allocatedSlot The allocated slot that this slot represents.
* @param owner The component from which this slot is allocated.
* @param slotNumber The number of the task slot on the instance.
*/
public SimpleSlot(AllocatedSlot allocatedSlot, SlotOwner owner, int slotNumber) {
this(allocatedSlot, owner, slotNumber, null, null);
}
/**
* Creates a new simple slot that belongs to the given shared slot and
* is identified by the given ID..
*
* @param parent The parent shared slot.
* @param owner The component from which this slot is allocated.
* @param slotNumber The number of the simple slot in its parent shared slot.
* @param groupID The ID that identifies the group that the slot belongs to.
*/
public SimpleSlot(SharedSlot parent, SlotOwner owner, int slotNumber, AbstractID groupID) {
this(parent.getAllocatedSlot(), owner, slotNumber, parent, groupID);
}
/**
* Creates a new simple slot that belongs to the given shared slot and
* is identified by the given ID..
*
* @param allocatedSlot The allocated slot that this slot represents.
* @param owner The component from which this slot is allocated.
* @param slotNumber The number of the simple slot in its parent shared slot.
* @param parent The parent shared slot.
* @param groupID The ID that identifies the group that the slot belongs to.
*/
private SimpleSlot(
AllocatedSlot allocatedSlot, SlotOwner owner, int slotNumber,
@Nullable SharedSlot parent, @Nullable AbstractID groupID) {
super(allocatedSlot, owner, slotNumber, parent, groupID);
}
// ------------------------------------------------------------------------
// Properties
// ------------------------------------------------------------------------
@Override
public int getNumberLeaves() {
return 1;
}
/**
* Gets the task execution attempt currently executed in this slot. This may return null, if no
* task execution attempt has been placed into this slot.
*
* @return The slot's task execution attempt, or null, if no task is executed in this slot, yet.
*/
public Execution getExecutedVertex() {
return executedTask;
}
/**
* Atomically sets the executed vertex, if no vertex has been assigned to this slot so far.
*
* @param executedVertex The vertex to assign to this slot.
* @return True, if the vertex was assigned, false, otherwise.
*/
public boolean setExecutedVertex(Execution executedVertex) {
if (executedVertex == null) {
throw new NullPointerException();
}
// check that we can actually run in this slot
if (isCanceled()) {
return false;
}
// atomically assign the vertex
if (!VERTEX_UPDATER.compareAndSet(this, null, executedVertex)) {
return false;
}
// we need to do a double check that we were not cancelled in the meantime
if (isCanceled()) {
this.executedTask = null;
return false;
}
return true;
}
/**
* Gets the locality information attached to this slot.
* @return The locality attached to the slot.
*/
public Locality getLocality() {
return locality;
}
/**
* Attached locality information to this slot.
* @param locality The locality attached to the slot.
*/
public void setLocality(Locality locality) {
this.locality = locality;
}
// ------------------------------------------------------------------------
// Cancelling & Releasing
// ------------------------------------------------------------------------
@Override
public void releaseSlot() {
if (!isCanceled()) {
// kill all tasks currently running in this slot
Execution exec = this.executedTask;
if (exec != null && !exec.isFinished()) {
exec.fail(new Exception("TaskManager was lost/killed: " + getTaskManagerLocation()));
}
// release directly (if we are directly allocated),
// otherwise release through the parent shared slot
if (getParent() == null) {
// we have to give back the slot to the owning instance
if (markCancelled()) {
getOwner().returnAllocatedSlot(this);
}
} else {
// we have to ask our parent to dispose us
getParent().releaseChild(this);
}
}
}
// ------------------------------------------------------------------------
// Utilities
// ------------------------------------------------------------------------
@Override
public String toString() {
return "SimpleSlot " + super.toString();
}
}