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HDFS-7790. Do not create optional fields in DFSInputStream unless they are needed (cmccabe) 

(cherry picked from commit 871cb56152)
This commit is contained in:
Colin Patrick Mccabe 2015-02-12 11:12:26 -08:00
parent 5696376e29
commit a9a361c549
2 changed files with 19 additions and 6 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -329,6 +329,9 @@ Release 2.7.0 - UNRELEASED
HDFS-7684. The host:port settings of the daemons should be trimmed before
use. (Anu Engineer via aajisaka)
HDFS-7790. Do not create optional fields in DFSInputStream unless they are
needed (cmccabe)
OPTIMIZATIONS
HDFS-7454. Reduce memory footprint for AclEntries in NameNode.

22
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
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@ -127,8 +127,15 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
* The value type can be either ByteBufferPool or ClientMmap, depending on
* whether we this is a memory-mapped buffer or not.
*/
private final IdentityHashStore<ByteBuffer, Object>
private IdentityHashStore<ByteBuffer, Object> extendedReadBuffers;
private synchronized IdentityHashStore<ByteBuffer, Object>
getExtendedReadBuffers() {
if (extendedReadBuffers == null) {
extendedReadBuffers = new IdentityHashStore<ByteBuffer, Object>(0);
}
return extendedReadBuffers;
}
public static class ReadStatistics {
public ReadStatistics() {
@ -236,7 +243,7 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
private final ConcurrentHashMap<DatanodeInfo, DatanodeInfo> deadNodes =
new ConcurrentHashMap<DatanodeInfo, DatanodeInfo>();
private final byte[] oneByteBuf = new byte[1]; // used for 'int read()'
private byte[] oneByteBuf; // used for 'int read()'
void addToDeadNodes(DatanodeInfo dnInfo) {
deadNodes.put(dnInfo, dnInfo);
@ -670,7 +677,7 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
}
dfsClient.checkOpen();
if (!extendedReadBuffers.isEmpty()) {
if ((extendedReadBuffers != null) && (!extendedReadBuffers.isEmpty())) {
final StringBuilder builder = new StringBuilder();
extendedReadBuffers.visitAll(new IdentityHashStore.Visitor<ByteBuffer, Object>() {
private String prefix = "";
@ -690,6 +697,9 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
@Override
public synchronized int read() throws IOException {
if (oneByteBuf == null) {
oneByteBuf = new byte[1];
}
int ret = read( oneByteBuf, 0, 1 );
return ( ret <= 0 ) ? -1 : (oneByteBuf[0] & 0xff);
}
@ -1708,7 +1718,7 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
}
buffer = ByteBufferUtil.fallbackRead(this, bufferPool, maxLength);
if (buffer != null) {
extendedReadBuffers.put(buffer, bufferPool);
getExtendedReadBuffers().put(buffer, bufferPool);
}
return buffer;
}
@ -1787,7 +1797,7 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
buffer = clientMmap.getMappedByteBuffer().asReadOnlyBuffer();
buffer.position((int)blockPos);
buffer.limit((int)(blockPos + length));
extendedReadBuffers.put(buffer, clientMmap);
getExtendedReadBuffers().put(buffer, clientMmap);
synchronized (infoLock) {
readStatistics.addZeroCopyBytes(length);
}
@ -1808,7 +1818,7 @@ implements ByteBufferReadable, CanSetDropBehind, CanSetReadahead,
@Override
public synchronized void releaseBuffer(ByteBuffer buffer) {
if (buffer == EMPTY_BUFFER) return;
Object val = extendedReadBuffers.remove(buffer);
Object val = getExtendedReadBuffers().remove(buffer);
if (val == null) {
throw new IllegalArgumentException("tried to release a buffer " +
"that was not created by this stream, " + buffer);