blob: e9f0f34c69e95f3cc0fe0019557f710518fa414c [file] [log] [blame]
/**
* 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.mapred;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.RandomAccessFile;
import com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.io.ReadaheadPool;
import org.apache.hadoop.io.ReadaheadPool.ReadaheadRequest;
import org.apache.hadoop.io.nativeio.NativeIO;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.hadoop.io.nativeio.NativeIO.POSIX.POSIX_FADV_DONTNEED;
import org.jboss.netty.handler.stream.ChunkedFile;
public class FadvisedChunkedFile extends ChunkedFile {
private static final Logger LOG =
LoggerFactory.getLogger(FadvisedChunkedFile.class);
private final Object closeLock = new Object();
private final boolean manageOsCache;
private final int readaheadLength;
private final ReadaheadPool readaheadPool;
private final FileDescriptor fd;
private final String identifier;
private volatile ReadaheadRequest readaheadRequest;
public FadvisedChunkedFile(RandomAccessFile file, long position, long count,
int chunkSize, boolean manageOsCache, int readaheadLength,
ReadaheadPool readaheadPool, String identifier) throws IOException {
super(file, position, count, chunkSize);
this.manageOsCache = manageOsCache;
this.readaheadLength = readaheadLength;
this.readaheadPool = readaheadPool;
this.fd = file.getFD();
this.identifier = identifier;
}
@VisibleForTesting
FileDescriptor getFd() {
return fd;
}
@Override
public Object nextChunk() throws Exception {
synchronized (closeLock) {
if (fd.valid()) {
if (manageOsCache && readaheadPool != null) {
readaheadRequest = readaheadPool
.readaheadStream(
identifier, fd, getCurrentOffset(), readaheadLength,
getEndOffset(), readaheadRequest);
}
return super.nextChunk();
} else {
return null;
}
}
}
@Override
public void close() throws Exception {
synchronized (closeLock) {
if (readaheadRequest != null) {
readaheadRequest.cancel();
readaheadRequest = null;
}
if (fd.valid() &&
manageOsCache && getEndOffset() - getStartOffset() > 0) {
try {
NativeIO.POSIX.getCacheManipulator().posixFadviseIfPossible(
identifier,
fd,
getStartOffset(), getEndOffset() - getStartOffset(),
POSIX_FADV_DONTNEED);
} catch (Throwable t) {
LOG.warn("Failed to manage OS cache for " + identifier +
" fd " + fd.toString(), t);
}
}
// fd becomes invalid upon closing
super.close();
}
}
}