hy00nc commented on a change in pull request #223: [NEMO-388] Off-heap memory management (reuse ByteBuffer) URL: https://github.com/apache/incubator-nemo/pull/223#discussion_r310888386
########## File path: runtime/executor/src/main/java/org/apache/nemo/runtime/executor/data/MemoryPoolAssigner.java ########## @@ -0,0 +1,170 @@ +/* + * 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.nemo.runtime.executor.data; + +import com.google.common.annotations.VisibleForTesting; +import net.jcip.annotations.ThreadSafe; +import org.apache.reef.tang.annotations.Parameter; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import org.apache.nemo.conf.JobConf; + +import javax.inject.Inject; +import java.nio.ByteBuffer; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.ConcurrentLinkedQueue; + +/** + * The MemoryPoolAssigner assigns the memory that Nemo uses for writing data blocks from the {@link MemoryPool}. + * Memory is represented in chunks of equal size. Consumers of off-heap memory acquire the memory by requesting + * a number of {@link MemoryChunk} they need. + * + * MemoryPoolAssigner currently supports allocation of off-heap memory only. + * + * The MemoryPoolAssigner pre-allocates user-defined amount of memory at the start. + * More memory can be allocated on-demand, but if there is no more memory to allocate, MemoryAllocationException + * is thrown and the job fails. // TODO #397: Separation of JVM heap region and off-heap memory region + */ +@ThreadSafe +public class MemoryPoolAssigner { + + private static final Logger LOG = LoggerFactory.getLogger(MemoryPoolAssigner.class.getName()); + + private final int chunkSize; + + private static final int MIN_CHUNK_SIZE_KB = 4; + + private final MemoryPool memoryPool; + + @Inject + public MemoryPoolAssigner(@Parameter(JobConf.MaxOffheapMb.class) final int maxOffheapMb, + @Parameter(JobConf.ChunkSizeKb.class) final int chunkSizeKb) { + if (chunkSizeKb < MIN_CHUNK_SIZE_KB) { + throw new IllegalArgumentException("Chunk size too small. Minimum chunk size is 4KB"); + } + final long maxNumChunks = (long) maxOffheapMb * 1024 / chunkSizeKb; + if (maxNumChunks > Integer.MAX_VALUE) { Review comment: As we track the number of chunks in integer, this check would make sense. Also, if the number of chunks exceeds MAX_INT, it means that the memory size is set to a too large number (which wouldn't be possible). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
