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[#995] Replace AtomicReference usage with AtomicReferenceFieldUpdater

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This will safe as an example 2gb mem when have 10 DefaultHandlerContext instances per connection and the connection count is 1000000.
Also kind of related to [#920]
This commit is contained in:
Norman Maurer 2013-01-30 13:41:41 +01:00
parent 03de5f479a
commit 1bb003d9ae
1 changed files with 47 additions and 29 deletions
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76
transport/src/main/java/io/netty/channel/DefaultChannelHandlerContext.java
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@ -32,7 +32,7 @@ import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import static io.netty.channel.DefaultChannelPipeline.*;
@ -64,10 +64,28 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
// To avoid such situation, we lazily creates an additional thread-safe buffer called
// 'bridge' so that the two handlers access each other's buffer only via the bridges.
// The content written into a bridge is flushed into the actual buffer by flushBridge().
private final AtomicReference<MessageBridge> inMsgBridge;
private AtomicReference<MessageBridge> outMsgBridge;
private final AtomicReference<ByteBridge> inByteBridge;
private AtomicReference<ByteBridge> outByteBridge;
//
// Note we use an AtomicReferenceFieldUpdater for atomic operations on these to safe memory. This will safe us
// 64 bytes per Bridge.
private volatile MessageBridge inMsgBridge;
private volatile MessageBridge outMsgBridge;
private volatile ByteBridge inByteBridge;
private volatile ByteBridge outByteBridge;
private static final AtomicReferenceFieldUpdater<DefaultChannelHandlerContext, MessageBridge> IN_MSG_BRIDGE_UPDATER
= AtomicReferenceFieldUpdater.newUpdater(DefaultChannelHandlerContext.class,
MessageBridge.class, "inMsgBridge");
private static final AtomicReferenceFieldUpdater<DefaultChannelHandlerContext, MessageBridge> OUT_MSG_BRIDGE_UPDATER
= AtomicReferenceFieldUpdater.newUpdater(DefaultChannelHandlerContext.class,
MessageBridge.class, "outMsgBridge");
private static final AtomicReferenceFieldUpdater<DefaultChannelHandlerContext, ByteBridge> IN_BYTE_BRIDGE_UPDATER
= AtomicReferenceFieldUpdater.newUpdater(DefaultChannelHandlerContext.class,
ByteBridge.class, "inByteBridge");
private static final AtomicReferenceFieldUpdater<DefaultChannelHandlerContext, ByteBridge> OUT_BYTE_BRIDGE_UPDATER
= AtomicReferenceFieldUpdater.newUpdater(DefaultChannelHandlerContext.class,
ByteBridge.class, "outByteBridge");
// Lazily instantiated tasks used to trigger events to a handler with different executor.
private Runnable invokeChannelRegisteredTask;
@ -148,14 +166,14 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (buf instanceof ByteBuf) {
inByteBuf = (ByteBuf) buf;
inByteBridge = new AtomicReference<ByteBridge>();
inByteBridge = null;
inMsgBuf = null;
inMsgBridge = null;
} else if (buf instanceof MessageBuf) {
inByteBuf = null;
inByteBridge = null;
inMsgBuf = (MessageBuf<Object>) buf;
inMsgBridge = new AtomicReference<MessageBridge>();
inMsgBridge = null;
} else {
throw new Error();
}
@ -252,7 +270,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (buf instanceof ByteBuf) {
outByteBuf = (ByteBuf) buf;
outByteBridge = new AtomicReference<ByteBridge>();
outByteBridge = null;
outMsgBuf = null;
outMsgBridge = null;
} else if (buf instanceof MessageBuf) {
@ -261,7 +279,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
@SuppressWarnings("unchecked")
MessageBuf<Object> msgBuf = (MessageBuf<Object>) buf;
outMsgBuf = msgBuf;
outMsgBridge = new AtomicReference<MessageBridge>();
outMsgBridge = null;
} else {
throw new Error();
}
@ -269,24 +287,24 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
private void fillBridge() {
if (inMsgBridge != null) {
MessageBridge bridge = inMsgBridge.get();
MessageBridge bridge = inMsgBridge;
if (bridge != null) {
bridge.fill();
}
} else if (inByteBridge != null) {
ByteBridge bridge = inByteBridge.get();
ByteBridge bridge = inByteBridge;
if (bridge != null) {
bridge.fill();
}
}
if (outMsgBridge != null) {
MessageBridge bridge = outMsgBridge.get();
MessageBridge bridge = outMsgBridge;
if (bridge != null) {
bridge.fill();
}
} else if (outByteBridge != null) {
ByteBridge bridge = outByteBridge.get();
ByteBridge bridge = outByteBridge;
if (bridge != null) {
bridge.fill();
}
@ -295,24 +313,24 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
private void flushBridge() {
if (inMsgBridge != null) {
MessageBridge bridge = inMsgBridge.get();
MessageBridge bridge = inMsgBridge;
if (bridge != null) {
bridge.flush(inMsgBuf);
}
} else if (inByteBridge != null) {
ByteBridge bridge = inByteBridge.get();
ByteBridge bridge = inByteBridge;
if (bridge != null) {
bridge.flush(inByteBuf);
}
}
if (outMsgBridge != null) {
MessageBridge bridge = outMsgBridge.get();
MessageBridge bridge = outMsgBridge;
if (bridge != null) {
bridge.flush(outMsgBuf);
}
} else if (outByteBridge != null) {
ByteBridge bridge = outByteBridge.get();
ByteBridge bridge = outByteBridge;
if (bridge != null) {
bridge.flush(outByteBuf);
}
@ -771,11 +789,11 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (ctx.executor().inEventLoop()) {
return ctx.inboundByteBuffer();
} else {
ByteBridge bridge = ctx.inByteBridge.get();
ByteBridge bridge = ctx.inByteBridge;
if (bridge == null) {
bridge = new ByteBridge(ctx);
if (!ctx.inByteBridge.compareAndSet(null, bridge)) {
bridge = ctx.inByteBridge.get();
if (!IN_BYTE_BRIDGE_UPDATER.compareAndSet(ctx, null, bridge)) {
bridge = ctx.inByteBridge;
}
}
return bridge.byteBuf;
@ -807,11 +825,11 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (ctx.executor().inEventLoop()) {
return ctx.inboundMessageBuffer();
} else {
MessageBridge bridge = ctx.inMsgBridge.get();
MessageBridge bridge = ctx.inMsgBridge;
if (bridge == null) {
bridge = new MessageBridge();
if (!ctx.inMsgBridge.compareAndSet(null, bridge)) {
bridge = ctx.inMsgBridge.get();
if (!IN_MSG_BRIDGE_UPDATER.compareAndSet(ctx, null, bridge)) {
bridge = ctx.inMsgBridge;
}
}
return bridge.msgBuf;
@ -830,11 +848,11 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (ctx.executor().inEventLoop()) {
return ctx.outboundByteBuffer();
} else {
ByteBridge bridge = ctx.outByteBridge.get();
ByteBridge bridge = ctx.outByteBridge;
if (bridge == null) {
bridge = new ByteBridge(ctx);
if (!ctx.outByteBridge.compareAndSet(null, bridge)) {
bridge = ctx.outByteBridge.get();
if (!OUT_BYTE_BRIDGE_UPDATER.compareAndSet(ctx, null, bridge)) {
bridge = ctx.outByteBridge;
}
}
return bridge.byteBuf;
@ -867,11 +885,11 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
if (ctx.executor().inEventLoop()) {
return ctx.outboundMessageBuffer();
} else {
MessageBridge bridge = ctx.outMsgBridge.get();
MessageBridge bridge = ctx.outMsgBridge;
if (bridge == null) {
bridge = new MessageBridge();
if (!ctx.outMsgBridge.compareAndSet(null, bridge)) {
bridge = ctx.outMsgBridge.get();
if (!OUT_MSG_BRIDGE_UPDATER.compareAndSet(ctx, null, bridge)) {
bridge = ctx.outMsgBridge;
}
}
return bridge.msgBuf;