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

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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 edb2250d35
commit 2d2e07578a
1 changed files with 32 additions and 43 deletions
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75
transport/src/main/java/io/netty/channel/DefaultChannelPipeline.java
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@ -29,7 +29,6 @@ import io.netty.util.internal.logging.InternalLoggerFactory;
import java.net.SocketAddress; import java.net.SocketAddress;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.HashMap;
import java.util.IdentityHashMap; import java.util.IdentityHashMap;
import java.util.Iterator; import java.util.Iterator;
import java.util.LinkedHashMap; import java.util.LinkedHashMap;
@ -61,8 +60,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
final AbstractChannelHandlerContext head; final AbstractChannelHandlerContext head;
final AbstractChannelHandlerContext tail; final AbstractChannelHandlerContext tail;
private final Map<String, AbstractChannelHandlerContext> name2ctx =
new HashMap<String, AbstractChannelHandlerContext>(4);
private final boolean touch = ResourceLeakDetector.isEnabled(); private final boolean touch = ResourceLeakDetector.isEnabled();
/** /**
@ -101,7 +98,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addFirst(EventExecutorGroup group, String name, ChannelHandler handler) { public ChannelPipeline addFirst(EventExecutorGroup group, String name, ChannelHandler handler) {
synchronized (this) { synchronized (this) {
name = filterName(name, handler); name = filterName(name, handler);
addFirst0(name, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler)); addFirst0(new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
} }
return this; return this;
} }
@ -110,12 +107,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addFirst(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) { public ChannelPipeline addFirst(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) {
synchronized (this) { synchronized (this) {
name = filterName(name, handler); name = filterName(name, handler);
addFirst0(name, new DefaultChannelHandlerContext(this, invoker, name, handler)); addFirst0(new DefaultChannelHandlerContext(this, invoker, name, handler));
} }
return this; return this;
} }
private void addFirst0(String name, AbstractChannelHandlerContext newCtx) { private void addFirst0(AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx); checkMultiplicity(newCtx);
AbstractChannelHandlerContext nextCtx = head.next; AbstractChannelHandlerContext nextCtx = head.next;
@ -124,8 +121,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
head.next = newCtx; head.next = newCtx;
nextCtx.prev = newCtx; nextCtx.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx); callHandlerAdded(newCtx);
} }
@ -138,7 +133,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addLast(EventExecutorGroup group, String name, ChannelHandler handler) { public ChannelPipeline addLast(EventExecutorGroup group, String name, ChannelHandler handler) {
synchronized (this) { synchronized (this) {
name = filterName(name, handler); name = filterName(name, handler);
addLast0(name, new DefaultChannelHandlerContext(this, findInvoker(group), name, handler)); addLast0(new DefaultChannelHandlerContext(this, findInvoker(group), name, handler));
} }
return this; return this;
} }
@ -147,12 +142,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
public ChannelPipeline addLast(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) { public ChannelPipeline addLast(ChannelHandlerInvoker invoker, String name, ChannelHandler handler) {
synchronized (this) { synchronized (this) {
name = filterName(name, handler); name = filterName(name, handler);
addLast0(name, new DefaultChannelHandlerContext(this, invoker, name, handler)); addLast0(new DefaultChannelHandlerContext(this, invoker, name, handler));
} }
return this; return this;
} }
private void addLast0(final String name, AbstractChannelHandlerContext newCtx) { private void addLast0(AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx); checkMultiplicity(newCtx);
AbstractChannelHandlerContext prev = tail.prev; AbstractChannelHandlerContext prev = tail.prev;
@ -161,8 +156,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
prev.next = newCtx; prev.next = newCtx;
tail.prev = newCtx; tail.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx); callHandlerAdded(newCtx);
} }
@ -176,7 +169,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) { synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName); AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler); 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; return this;
} }
@ -187,13 +180,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) { synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName); AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler); name = filterName(name, handler);
addBefore0(name, ctx, new DefaultChannelHandlerContext(this, invoker, name, handler)); addBefore0(ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
} }
return this; return this;
} }
private void addBefore0( private void addBefore0(AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
final String name, AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx); checkMultiplicity(newCtx);
newCtx.prev = ctx.prev; newCtx.prev = ctx.prev;
@ -201,8 +193,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
ctx.prev.next = newCtx; ctx.prev.next = newCtx;
ctx.prev = newCtx; ctx.prev = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx); callHandlerAdded(newCtx);
} }
@ -216,7 +206,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) { synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName); AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler); 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; return this;
} }
@ -228,12 +218,12 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) { synchronized (this) {
AbstractChannelHandlerContext ctx = getContextOrDie(baseName); AbstractChannelHandlerContext ctx = getContextOrDie(baseName);
name = filterName(name, handler); name = filterName(name, handler);
addAfter0(name, ctx, new DefaultChannelHandlerContext(this, invoker, name, handler)); addAfter0(ctx, new DefaultChannelHandlerContext(this, invoker, name, handler));
} }
return this; return this;
} }
private void addAfter0(String name, AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) { private void addAfter0(AbstractChannelHandlerContext ctx, AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx); checkMultiplicity(newCtx);
newCtx.prev = ctx; newCtx.prev = ctx;
@ -241,8 +231,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
ctx.next.prev = newCtx; ctx.next.prev = newCtx;
ctx.next = newCtx; ctx.next = newCtx;
name2ctx.put(name, newCtx);
callHandlerAdded(newCtx); callHandlerAdded(newCtx);
} }
@ -376,11 +364,11 @@ final class DefaultChannelPipeline implements ChannelPipeline {
synchronized (this) { 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 // 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. // 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'. String baseName = name.substring(0, name.length() - 1); // Strip the trailing '0'.
for (int i = 1;; i ++) { for (int i = 1;; i ++) {
String newName = baseName + i; String newName = baseName + i;
if (!name2ctx.containsKey(newName)) { if (context0(newName) == null) {
name = newName; name = newName;
break; break;
} }
@ -448,7 +436,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
AbstractChannelHandlerContext next = ctx.next; AbstractChannelHandlerContext next = ctx.next;
prev.next = next; prev.next = next;
next.prev = prev; next.prev = prev;
name2ctx.remove(ctx.name());
callHandlerRemoved(ctx); callHandlerRemoved(ctx);
} }
@ -503,15 +490,14 @@ final class DefaultChannelPipeline implements ChannelPipeline {
new DefaultChannelHandlerContext(this, ctx.invoker, newName, newHandler); new DefaultChannelHandlerContext(this, ctx.invoker, newName, newHandler);
if (!newCtx.channel().isRegistered() || newCtx.executor().inEventLoop()) { if (!newCtx.channel().isRegistered() || newCtx.executor().inEventLoop()) {
replace0(ctx, newName, newCtx); replace0(ctx, newCtx);
return ctx.handler(); return ctx.handler();
} else { } else {
final String finalNewName = newName;
future = newCtx.executor().submit(new Runnable() { future = newCtx.executor().submit(new Runnable() {
@Override @Override
public void run() { public void run() {
synchronized (DefaultChannelPipeline.this) { synchronized (DefaultChannelPipeline.this) {
replace0(ctx, finalNewName, newCtx); replace0(ctx, newCtx);
} }
} }
}); });
@ -526,8 +512,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
return ctx.handler(); return ctx.handler();
} }
private void replace0(AbstractChannelHandlerContext oldCtx, String newName, private void replace0(AbstractChannelHandlerContext oldCtx, AbstractChannelHandlerContext newCtx) {
AbstractChannelHandlerContext newCtx) {
checkMultiplicity(newCtx); checkMultiplicity(newCtx);
AbstractChannelHandlerContext prev = oldCtx.prev; AbstractChannelHandlerContext prev = oldCtx.prev;
@ -542,11 +527,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
prev.next = newCtx; prev.next = newCtx;
next.prev = 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 // update the reference to the replacement so forward of buffered content will work correctly
oldCtx.prev = newCtx; oldCtx.prev = newCtx;
oldCtx.next = newCtx; oldCtx.next = newCtx;
@ -724,9 +704,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
throw new NullPointerException("name"); throw new NullPointerException("name");
} }
synchronized (this) { return context0(name);
return name2ctx.get(name);
}
} }
@Override @Override
@ -851,8 +829,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
* Removes all handlers from the pipeline one by one from tail (exclusive) to head (exclusive) to trigger * Removes all handlers from the pipeline one by one from tail (exclusive) to head (exclusive) to trigger
* handlerRemoved(). * handlerRemoved().
* *
* Note that we traverse up the pipeline ({@link #destroyUp(AbstractChannelHandlerContext)}) * Note that we traverse up the pipeline ({@link #destroyUp(AbstractChannelHandlerContext, boolean)})
* before traversing down ({@link #destroyDown(Thread, AbstractChannelHandlerContext)}) so that * before traversing down ({@link #destroyDown(Thread, AbstractChannelHandlerContext, boolean)}) so that
* the handlers are removed after all events are handled. * the handlers are removed after all events are handled.
* *
* See: https://github.com/netty/netty/issues/3156 * See: https://github.com/netty/netty/issues/3156
@ -1063,13 +1041,24 @@ final class DefaultChannelPipeline implements ChannelPipeline {
return generateName(handler); return generateName(handler);
} }
if (!name2ctx.containsKey(name)) { if (context0(name) == null) {
return name; return name;
} }
throw new IllegalArgumentException("Duplicate handler name: " + 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) { private AbstractChannelHandlerContext getContextOrDie(String name) {
AbstractChannelHandlerContext ctx = (AbstractChannelHandlerContext) context(name); AbstractChannelHandlerContext ctx = (AbstractChannelHandlerContext) context(name);
if (ctx == null) { if (ctx == null) {