Remove HashMap for lookup name / ctx from DefaultChannelPipeline to reduce memory footprint

Motivation:

If you start to have 1M+ concurrent connections memory footprint can be come a big issue. We should try to reduce it as much as possible in the core of netty.

Modifications:

- Remove HashMap that was used to store name to ctx mapping. This was only used for validation and access a handler by name. As a pipeline is not expected to be very long (like 100+ handlers) we can just walk the linked list structure to find the ctx with a given name.

Result:

Less memory footprint of the DefaultChannelPipeline.
This commit is contained in:
Norman Maurer 2015-11-15 08:55:12 -08:00
parent ba19837f2f
commit ab66b1daba

View File

@ -30,7 +30,6 @@ import io.netty.util.internal.logging.InternalLoggerFactory;
import java.net.SocketAddress;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
@ -62,8 +61,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
final AbstractChannelHandlerContext head;
final AbstractChannelHandlerContext tail;
private final Map<String, AbstractChannelHandlerContext> name2ctx =
new HashMap<String, AbstractChannelHandlerContext>(4);
private final boolean touch = ResourceLeakDetector.getLevel() != ResourceLeakDetector.Level.DISABLED;
/**
@ -102,7 +99,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addFirst(EventExecutorGroup group, String name, ChannelHandler handler) {
synchronized (this) {
name = filterName(name, handler);
addFirst0(name, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
addFirst0(new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
}
return this;
}
@ -111,12 +108,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addFirst(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) {
synchronized (this) {
name = filterName(name, handler);
addFirst0(name, new DefaultChannelHandlerContext(this, invoker, name, handler));
addFirst0(new DefaultChannelHandlerContext(this, invoker, name, handler));
}
return this;
}
private void addFirst0(String name, AbstractChannelHandlerContext newCtx) {
private void addFirst0(AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx);
AbstractChannelHandlerContext nextCtx = head.next;
@ -125,8 +122,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
head.next = newCtx;
nextCtx.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx);
}
@ -139,7 +134,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addLast(EventExecutorGroup group, String name, ChannelHandler handler) {
synchronized (this) {
name = filterName(name, handler);
addLast0(name, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
addLast0(new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
}
return this;
}
@ -148,12 +143,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addLast(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) {
synchronized (this) {
name = filterName(name, handler);
addLast0(name, new DefaultChannelHandlerContext(this, invoker, name, handler));
addLast0(new DefaultChannelHandlerContext(this, invoker, name, handler));
}
return this;
}
private void addLast0(final String name, AbstractChannelHandlerContext newCtx) {
private void addLast0(AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx);
AbstractChannelHandlerContext prev = tail.prev;
@ -162,8 +157,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
prev.next = newCtx;
tail.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx);
}
@ -177,7 +170,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler);
addBefore0(name, ctx, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
addBefore0(ctx, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
}
return this;
}
@ -188,13 +181,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler);
addBefore0(name, ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
addBefore0(ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
}
return this;
}
private void addBefore0(
final String name, AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
private void addBefore0(AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx);
newCtx.prev = ctx.prev;
@ -202,8 +194,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
ctx.prev.next = newCtx;
ctx.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx);
}
@ -217,7 +207,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler);
addAfter0(name, ctx, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
addAfter0(ctx, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
}
return this;
}
@ -229,12 +219,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler);
addAfter0(name, ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
addAfter0(ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
}
return this;
}
private void addAfter0(String name, AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
private void addAfter0(AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx);
newCtx.prev = ctx;
@ -242,8 +232,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
ctx.next.prev = newCtx;
ctx.next = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx);
}
@ -377,11 +365,11 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) {
// It's not very likely for a user to put more than one handler of the same type, but make sure to avoid
// any name conflicts. Note that we don't cache the names generated here.
if (name2ctx.containsKey(name)) {
if (context0(name) != null) {
String baseName = name.substring(0, name.length() - 1); // Strip the trailing '0'.
for (int i = 1;; i ++) {
String newName = baseName + i;
if (!name2ctx.containsKey(newName)) {
if (context0(newName) == null) {
name = newName;
break;
}
@ -449,7 +437,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
AbstractChannelHandlerContext next = ctx.next;
prev.next = next;
next.prev = prev;
name2ctx.remove(ctx.name());
callHandlerRemoved(ctx);
}
@ -504,15 +491,14 @@ final class DefaultChannelPipeline implements ChannelPipeline {
new DefaultChannelHandlerContext(this, ctx.invoker, newName, newHandler);
if (!newCtx.channel().isRegistered() || newCtx.executor().inEventLoop()) {
replace0(ctx, newName, newCtx);
replace0(ctx, newCtx);
return ctx.handler();
} else {
final String finalNewName = newName;
future = newCtx.executor().submit(new Runnable() {
@Override
public void run() {
synchronized (DefaultChannelPipeline.this) {
replace0(ctx, finalNewName, newCtx);
replace0(ctx, newCtx);
}
}
});
@ -527,8 +513,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
return ctx.handler();
}
private void replace0(AbstractChannelHandlerContext oldCtx, String newName,
AbstractChannelHandlerContext newCtx) {
private void replace0(AbstractChannelHandlerContext oldCtx, AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx);
AbstractChannelHandlerContext prev = oldCtx.prev;
@ -543,11 +528,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
prev.next = newCtx;
next.prev = newCtx;
if (!oldCtx.name().equals(newName)) {
name2ctx.remove(oldCtx.name());
}
name2ctx.put(newName, newCtx);
// update the reference to the replacement so forward of buffered content will work correctly
oldCtx.prev = newCtx;
oldCtx.next = newCtx;
@ -733,9 +713,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
throw new NullPointerException("name");
}
synchronized (this) {
return name2ctx.get(name);
}
return context0(name);
}
@Override
@ -860,8 +838,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
* Removes all handlers from the pipeline one by one from tail (exclusive) to head (exclusive) to trigger
* handlerRemoved().
*
* Note that we traverse up the pipeline ({@link #destroyUp(AbstractChannelHandlerContext)})
* before traversing down ({@link #destroyDown(Thread, AbstractChannelHandlerContext)}) so that
* Note that we traverse up the pipeline ({@link #destroyUp(AbstractChannelHandlerContext, boolean)})
* before traversing down ({@link #destroyDown(Thread, AbstractChannelHandlerContext, boolean)}) so that
* the handlers are removed after all events are handled.
*
* See: https://github.com/netty/netty/issues/3156
@ -1072,13 +1050,24 @@ final class DefaultChannelPipeline implements ChannelPipeline {
return generateName(handler);
}
if (!name2ctx.containsKey(name)) {
if (context0(name) == null) {
return name;
}
throw new IllegalArgumentException("Duplicate handler name: " + name);
}
private AbstractChannelHandlerContext context0(String name) {
AbstractChannelHandlerContext context = head.next;
while (context != tail) {
if (context.name().equals(name)) {
return context;
}
context = context.next;
}
return null;
}
private AbstractChannelHandlerContext getContextOrDie(String name) {
AbstractChannelHandlerContext ctx = (AbstractChannelHandlerContext) context(name);
if (ctx == null) {