085a61a310
Motivation: When Netty runs in a managed environment such as web application server, Netty needs to provide an explicit way to remove the thread-local variables it created to prevent class loader leaks. FastThreadLocal uses different execution paths for storing a thread-local variable depending on the type of the current thread. It increases the complexity of thread-local removal. Modifications: - Moved FastThreadLocal and FastThreadLocalThread out of the internal package so that a user can use it. - FastThreadLocal now keeps track of all thread local variables it has initialized, and calling FastThreadLocal.removeAll() will remove all thread-local variables of the caller thread. - Added FastThreadLocal.size() for diagnostics and tests - Introduce InternalThreadLocalMap which is a mixture of hard-wired thread local variable fields and extensible indexed variables - FastThreadLocal now uses InternalThreadLocalMap to implement a thread-local variable. - Added ThreadDeathWatcher.unwatch() so that PooledByteBufAllocator tells it to stop watching when its thread-local cache has been freed by FastThreadLocal.removeAll(). - Added FastThreadLocalTest to ensure that removeAll() works - Added microbenchmark for FastThreadLocal and JDK ThreadLocal - Upgraded to JMH 0.9 Result: - A user can remove all thread-local variables Netty created, as long as he or she did not exit from the current thread. (Note that there's no way to remove a thread-local variable from outside of the thread.) - FastThreadLocal exposes more useful operations such as isSet() because we always implement a thread local variable via InternalThreadLocalMap instead of falling back to JDK ThreadLocal. - FastThreadLocalBenchmark shows that this change improves the performance of FastThreadLocal even more.
58 lines
2.0 KiB
Java
58 lines
2.0 KiB
Java
/*
|
|
* Copyright 2014 The Netty Project
|
|
*
|
|
* The Netty Project 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 io.netty.util.internal;
|
|
|
|
import io.netty.util.concurrent.FastThreadLocal;
|
|
|
|
import java.nio.charset.Charset;
|
|
import java.nio.charset.CharsetDecoder;
|
|
import java.nio.charset.CharsetEncoder;
|
|
import java.util.Map;
|
|
import java.util.concurrent.atomic.AtomicInteger;
|
|
|
|
/**
|
|
* The internal data structure that stores the thread-local variables for Netty and all {@link FastThreadLocal}s.
|
|
* Note that this class is for internal use only and is subject to change at any time. Use {@link FastThreadLocal}
|
|
* unless you know what you are doing.
|
|
*/
|
|
class UnpaddedInternalThreadLocalMap {
|
|
|
|
static ThreadLocal<InternalThreadLocalMap> slowThreadLocalMap;
|
|
static final AtomicInteger nextIndex = new AtomicInteger();
|
|
|
|
/** Used by {@link FastThreadLocal} */
|
|
Object[] indexedVariables;
|
|
|
|
// Core thread-locals
|
|
int futureListenerStackDepth;
|
|
int localChannelReaderStackDepth;
|
|
Map<Class<?>, Boolean> handlerSharableCache;
|
|
IntegerHolder counterHashCode;
|
|
ThreadLocalRandom random;
|
|
Map<Class<?>, TypeParameterMatcher> typeParameterMatcherGetCache;
|
|
Map<Class<?>, Map<String, TypeParameterMatcher>> typeParameterMatcherFindCache;
|
|
|
|
// String-related thread-locals
|
|
StringBuilder stringBuilder;
|
|
Map<Charset, CharsetEncoder> charsetEncoderCache;
|
|
Map<Charset, CharsetDecoder> charsetDecoderCache;
|
|
|
|
UnpaddedInternalThreadLocalMap(Object[] indexedVariables) {
|
|
this.indexedVariables = indexedVariables;
|
|
}
|
|
}
|