| /** |
| * 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.hadoop.hdfs.server.datanode; |
| |
| import java.io.File; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /* |
| * This class is a container of multiple thread pools, each for a volume, |
| * so that we can schedule async disk operations easily. |
| * |
| * Examples of async disk operations are deletion of block files in FSDataset. |
| * We don't want to create a new thread for each of the deletion request, and |
| * we don't want to do all deletions in the heartbeat thread since deletion |
| * can be slow, and we don't want to use a single thread pool because that |
| * is inefficient when we have more than 1 volume. AsyncDiskService is the |
| * solution for these. |
| * |
| * This class is used inside FSDataset. |
| * |
| * In the future, we should extract AsyncDiskService and put it into common. |
| * The FSDataset-specific logic should reside here. |
| */ |
| class FSDatasetAsyncDiskService { |
| |
| public static final Log LOG = LogFactory.getLog(FSDatasetAsyncDiskService.class); |
| |
| // ThreadPool core pool size |
| private static final int CORE_THREADS_PER_VOLUME = 1; |
| // ThreadPool maximum pool size |
| private static final int MAXIMUM_THREADS_PER_VOLUME = 4; |
| // ThreadPool keep-alive time for threads over core pool size |
| private static final long THREADS_KEEP_ALIVE_SECONDS = 60; |
| |
| private final ThreadGroup threadGroup = new ThreadGroup("async disk service"); |
| |
| private HashMap<File, ThreadPoolExecutor> executors |
| = new HashMap<File, ThreadPoolExecutor>(); |
| |
| /** |
| * Create a AsyncDiskServices with a set of volumes (specified by their |
| * root directories). |
| * |
| * The AsyncDiskServices uses one ThreadPool per volume to do the async |
| * disk operations. |
| * |
| * @param volumes The roots of the data volumes. |
| */ |
| FSDatasetAsyncDiskService(File[] volumes) { |
| |
| // Create one ThreadPool per volume |
| for (int v = 0 ; v < volumes.length; v++) { |
| final File vol = volumes[v]; |
| ThreadFactory threadFactory = new ThreadFactory() { |
| int counter = 0; |
| |
| @Override |
| public Thread newThread(Runnable r) { |
| int thisIndex; |
| synchronized (this) { |
| thisIndex = counter++; |
| } |
| Thread t = new Thread(threadGroup, r); |
| t.setName("Async disk worker #" + thisIndex + |
| " for volume " + vol); |
| return t; |
| } |
| }; |
| |
| ThreadPoolExecutor executor = new ThreadPoolExecutor( |
| CORE_THREADS_PER_VOLUME, MAXIMUM_THREADS_PER_VOLUME, |
| THREADS_KEEP_ALIVE_SECONDS, TimeUnit.SECONDS, |
| new LinkedBlockingQueue<Runnable>(), threadFactory); |
| |
| // This can reduce the number of running threads |
| executor.allowCoreThreadTimeOut(true); |
| executors.put(vol, executor); |
| } |
| |
| } |
| |
| /** |
| * Execute the task sometime in the future, using ThreadPools. |
| */ |
| synchronized void execute(File root, Runnable task) { |
| if (executors == null) { |
| throw new RuntimeException("AsyncDiskService is already shutdown"); |
| } |
| ThreadPoolExecutor executor = executors.get(root); |
| if (executor == null) { |
| throw new RuntimeException("Cannot find root " + root |
| + " for execution of task " + task); |
| } else { |
| executor.execute(task); |
| } |
| } |
| |
| /** |
| * Gracefully shut down all ThreadPool. Will wait for all deletion |
| * tasks to finish. |
| */ |
| synchronized void shutdown() { |
| |
| if (executors == null) { |
| |
| LOG.warn("AsyncDiskService has already shut down."); |
| |
| } else { |
| LOG.info("Shutting down all async disk service threads..."); |
| |
| for (Map.Entry<File, ThreadPoolExecutor> e |
| : executors.entrySet()) { |
| e.getValue().shutdown(); |
| } |
| // clear the executor map so that calling execute again will fail. |
| executors = null; |
| |
| LOG.info("All async disk service threads have been shut down."); |
| } |
| } |
| |
| /** |
| * Delete the block file and meta file from the disk asynchronously, adjust |
| * dfsUsed statistics accordingly. |
| */ |
| void deleteAsync(FSDataset.FSVolume volume, String bpid, File blockFile, |
| File metaFile, String blockName) { |
| DataNode.LOG.info("Scheduling block " + blockName + " file " + blockFile |
| + " for deletion"); |
| ReplicaFileDeleteTask deletionTask = |
| new ReplicaFileDeleteTask(volume, bpid, blockFile, metaFile, |
| blockName); |
| execute(volume.getCurrentDir(), deletionTask); |
| } |
| |
| /** A task for deleting a block file and its associated meta file, as well |
| * as decrement the dfs usage of the volume. |
| */ |
| static class ReplicaFileDeleteTask implements Runnable { |
| final FSDataset.FSVolume volume; |
| final String blockPoolId; |
| final File blockFile; |
| final File metaFile; |
| final String blockName; |
| |
| ReplicaFileDeleteTask(FSDataset.FSVolume volume, String bpid, |
| File blockFile, File metaFile, String blockName) { |
| this.volume = volume; |
| this.blockPoolId = bpid; |
| this.blockFile = blockFile; |
| this.metaFile = metaFile; |
| this.blockName = blockName; |
| } |
| |
| FSDataset.FSVolume getVolume() { |
| return volume; |
| } |
| |
| @Override |
| public String toString() { |
| // Called in AsyncDiskService.execute for displaying error messages. |
| return "deletion of block " + blockPoolId + " " + blockName |
| + " with block file " + blockFile + " and meta file " + metaFile |
| + " from volume " + volume; |
| } |
| |
| @Override |
| public void run() { |
| long dfsBytes = blockFile.length() + metaFile.length(); |
| if ( !blockFile.delete() || ( !metaFile.delete() && metaFile.exists() ) ) { |
| DataNode.LOG.warn("Unexpected error trying to delete block " |
| + blockPoolId + " " + blockName + " at file " + blockFile |
| + ". Ignored."); |
| } else { |
| volume.decDfsUsed(blockPoolId, dfsBytes); |
| DataNode.LOG.info("Deleted block " + blockPoolId + " " + blockName |
| + " at file " + blockFile); |
| } |
| } |
| }; |
| |
| |
| } |