[FLINK-1320] [core] Add an off-heap variant of the managed memory

This closes #1093

flink-core/src/main/java/org/apache/flink/configuration/ConfigConstants.java

@@ -125,9 +125,14 @@ public final class ConfigConstants {
 	public static final String TASK_MANAGER_MEMORY_FRACTION_KEY = "taskmanager.memory.fraction";
 
 	/**
-	 * The key for the config parameter defining whether the memory manager allocates memory lazy.
+	 * The fraction of off-heap memory relative to the heap size.
 	 */
-	public static final String TASK_MANAGER_MEMORY_LAZY_ALLOCATION_KEY = "taskmanager.memory.lazyalloc";
+	public static final String TASK_MANAGER_MEMORY_OFF_HEAP_RATIO_KEY = "taskmanager.memory.off-heap-ratio";
+
+	/**
+	 * The config parameter defining the memory allocation method (JVM heap or off-heap).
+	*/
+	public static final String TASK_MANAGER_MEMORY_OFF_HEAP_KEY = "taskmanager.memory.off-heap";
 
 	/**
 	 * The config parameter defining the number of buffers used in the network stack. This defines the
@@ -542,6 +547,11 @@ public final class ConfigConstants {
 	 */
 	public static final float DEFAULT_MEMORY_MANAGER_MEMORY_FRACTION = 0.7f;
 
+	/**
+	 * The default ratio of heap to off-heap memory, when the TaskManager is started with off-heap memory.
+	 */
+	public static final float DEFAULT_MEMORY_MANAGER_MEMORY_OFF_HEAP_RATIO = 3.0f;
+
 	/**
 	 * Default number of buffers used in the network stack.
 	 */

flink-core/src/main/java/org/apache/flink/core/memory/HeapMemorySegment.java

@@ -0,0 +1,203 @@
+/*
+ * 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.core.memory;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Objects;
+
+/**
+ * This class represents a piece of heap memory managed by Flink.
+ * The segment is backed by a byte array and features random put and get methods for the basic types,
+ * as well as compare and swap methods.
+ * <p>
+ * This class specialized byte access and byte copy calls for heap memory, while reusing the
+ * multi-byte type accesses and cross-segment operations from the MemorySegment.
+ * <p>
+ * Note that memory segments should usually not be allocated manually, but rather through the
+ * {@link MemorySegmentFactory}.
+ */
+public final class HeapMemorySegment extends MemorySegment {
+
+	/** An extra reference to the heap memory, so we can let byte array checks fail 
+	 *  by the built-in checks automatically without extra checks */
+	private byte[] memory;
+
+	/**
+	 * Creates a new memory segment that represents the data in the given byte array.
+	 * The owner of this memory segment is null.
+	 *
+	 * @param memory The byte array that holds the data.
+	 */
+	HeapMemorySegment(byte[] memory) {
+		this(memory, null);
+	}
+
+	/**
+	 * Creates a new memory segment that represents the data in the given byte array.
+	 * The memory segment references the given owner.
+	 *
+	 * @param memory The byte array that holds the data.
+	 * @param owner The owner referenced by the memory segment.
+	 */
+	HeapMemorySegment(byte[] memory, Object owner) {
+		super(Objects.requireNonNull(memory), owner);
+		this.memory = memory;
+	}
+
+	// -------------------------------------------------------------------------
+	//  MemorySegment operations
+	// -------------------------------------------------------------------------
+
+	@Override
+	public void free() {
+		super.free();
+		this.memory = null;
+	}
+
+	@Override
+	public ByteBuffer wrap(int offset, int length) {
+		try {
+			return ByteBuffer.wrap(this.memory, offset, length);
+		}
+		catch (NullPointerException e) {
+			throw new IllegalStateException("segment has been freed");
+		}
+	}
+
+	/**
+	 * Gets the byte array that backs this memory segment.
+	 *
+	 * @return The byte array that backs this memory segment, or null, if the segment has been freed.
+	 */
+	public byte[] getArray() {
+		return this.heapMemory;
+	}
+
+	// ------------------------------------------------------------------------
+	//                    Random Access get() and put() methods
+	// ------------------------------------------------------------------------
+
+	@Override
+	public final byte get(int index) {
+		return this.memory[index];
+	}
+
+	@Override
+	public final void put(int index, byte b) {
+		this.memory[index] = b;
+	}
+
+	@Override
+	public final void get(int index, byte[] dst) {
+		get(index, dst, 0, dst.length);
+	}
+
+	@Override
+	public final void put(int index, byte[] src) {
+		put(index, src, 0, src.length);
+	}
+
+	@Override
+	public final void get(int index, byte[] dst, int offset, int length) {
+		// system arraycopy does the boundary checks anyways, no need to check extra
+		System.arraycopy(this.memory, index, dst, offset, length);
+	}
+
+	@Override
+	public final void put(int index, byte[] src, int offset, int length) {
+		// system arraycopy does the boundary checks anyways, no need to check extra
+		System.arraycopy(src, offset, this.memory, index, length);
+	}
+
+	@Override
+	public final boolean getBoolean(int index) {
+		return this.memory[index] != 0;
+	}
+
+	@Override
+	public final void putBoolean(int index, boolean value) {
+		this.memory[index] = (byte) (value ? 1 : 0);
+	}
+
+	// -------------------------------------------------------------------------
+	//                     Bulk Read and Write Methods
+	// -------------------------------------------------------------------------
+
+	@Override
+	public final void get(DataOutput out, int offset, int length) throws IOException {
+		out.write(this.memory, offset, length);
+	}
+
+	@Override
+	public final void put(DataInput in, int offset, int length) throws IOException {
+		in.readFully(this.memory, offset, length);
+	}
+
+	@Override
+	public final void get(int offset, ByteBuffer target, int numBytes) {
+		// ByteBuffer performs the boundary checks
+		target.put(this.memory, offset, numBytes);
+	}
+
+	@Override
+	public final void put(int offset, ByteBuffer source, int numBytes) {
+		// ByteBuffer performs the boundary checks
+		source.get(this.memory, offset, numBytes);
+	}
+
+	// -------------------------------------------------------------------------
+	//                             Factoring
+	// -------------------------------------------------------------------------
+
+	/**
+	 * A memory segment factory that produces heap memory segments. Note that this factory does not
+	 * support to allocate off-heap memory.
+	 */
+	public static final class HeapMemorySegmentFactory implements MemorySegmentFactory.Factory {
+
+		@Override
+		public HeapMemorySegment wrap(byte[] memory) {
+			return new HeapMemorySegment(memory);
+		}
+
+		@Override
+		public HeapMemorySegment allocateUnpooledSegment(int size, Object owner) {
+			return new HeapMemorySegment(new byte[size], owner);
+		}
+
+		@Override
+		public HeapMemorySegment wrapPooledHeapMemory(byte[] memory, Object owner) {
+			return new HeapMemorySegment(memory, owner);
+		}
+
+		@Override
+		public HeapMemorySegment wrapPooledOffHeapMemory(ByteBuffer memory, Object owner) {
+			throw new UnsupportedOperationException(
+					"The MemorySegment factory was not initialized for off-heap memory.");
+		}
+
+		/** prevent external instantiation */
+		HeapMemorySegmentFactory() {}
+	};
+
+	public static final HeapMemorySegmentFactory FACTORY = new HeapMemorySegmentFactory();
+}