| /** |
| * 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.nfs.nfs3; |
| |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * This class is a thread pool to easily schedule async data operations. Current |
| * async data operation is write back operation. In the future, we could use it |
| * for readahead operations too. |
| */ |
| public class AsyncDataService { |
| static final Logger LOG = LoggerFactory.getLogger(AsyncDataService.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 data service"); |
| private ThreadFactory threadFactory = null; |
| private ThreadPoolExecutor executor = null; |
| |
| public AsyncDataService() { |
| threadFactory = new ThreadFactory() { |
| @Override |
| public Thread newThread(Runnable r) { |
| return new Thread(threadGroup, r); |
| } |
| }; |
| |
| 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); |
| } |
| |
| /** |
| * Execute the task sometime in the future. |
| */ |
| synchronized void execute(Runnable task) { |
| if (executor == null) { |
| throw new RuntimeException("AsyncDataService is already shutdown"); |
| } |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Current active thread number: " + executor.getActiveCount() |
| + " queue size: " + executor.getQueue().size() |
| + " scheduled task number: " + executor.getTaskCount()); |
| } |
| executor.execute(task); |
| } |
| |
| /** |
| * Gracefully shut down the ThreadPool. Will wait for all data tasks to |
| * finish. |
| */ |
| synchronized void shutdown() { |
| if (executor == null) { |
| LOG.warn("AsyncDataService has already shut down."); |
| } else { |
| LOG.info("Shutting down all async data service threads..."); |
| executor.shutdown(); |
| |
| // clear the executor so that calling execute again will fail. |
| executor = null; |
| LOG.info("All async data service threads have been shut down"); |
| } |
| } |
| |
| /** |
| * Write the data to HDFS asynchronously |
| */ |
| void writeAsync(OpenFileCtx openFileCtx) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Scheduling write back task for fileId: " |
| + openFileCtx.getLatestAttr().getFileId()); |
| } |
| WriteBackTask wbTask = new WriteBackTask(openFileCtx); |
| execute(wbTask); |
| } |
| |
| /** |
| * A task to write data back to HDFS for a file. Since only one thread can |
| * write to a file, there should only be one task at any time for a file |
| * (in queue or executing), and this should be guaranteed by the caller. |
| */ |
| static class WriteBackTask implements Runnable { |
| |
| OpenFileCtx openFileCtx; |
| |
| WriteBackTask(OpenFileCtx openFileCtx) { |
| this.openFileCtx = openFileCtx; |
| } |
| |
| OpenFileCtx getOpenFileCtx() { |
| return openFileCtx; |
| } |
| |
| @Override |
| public String toString() { |
| // Called in AsyncDataService.execute for displaying error messages. |
| return "write back data for fileId" |
| + openFileCtx.getLatestAttr().getFileId() + " with nextOffset " |
| + openFileCtx.getNextOffset(); |
| } |
| |
| @Override |
| public void run() { |
| try { |
| openFileCtx.executeWriteBack(); |
| } catch (Throwable t) { |
| LOG.error("Async data service got error: ", t); |
| } |
| } |
| } |
| } |