Author: slaurent
Date: Thu Dec 9 22:11:27 2010
New Revision: 1044145
URL: http://svn.apache.org/viewvc?rev=1044145&view=rev
Log:
bug 49159: Improve ThreadLocal memory leak clean-up
https://issues.apache.org/bugzilla/show_bug.cgi?id=49159
Use a dedicated thread when calling web application code when it is started and
stopped (calls to Listeners, Filters, Servlets).
Added:
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
(with props)
tomcat/trunk/test/org/apache/tomcat/util/threads/
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
(with props)
Modified:
tomcat/trunk/java/org/apache/catalina/core/StandardContext.java
Modified: tomcat/trunk/java/org/apache/catalina/core/StandardContext.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/core/StandardContext.java?rev=1044145&r1=1044144&r2=1044145&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/catalina/core/StandardContext.java (original)
+++ tomcat/trunk/java/org/apache/catalina/core/StandardContext.java Thu Dec 9
22:11:27 2010
@@ -37,6 +37,7 @@ import java.util.Map;
import java.util.Set;
import java.util.Stack;
import java.util.TreeMap;
+import java.util.concurrent.Callable;
import javax.management.ListenerNotFoundException;
import javax.management.MBeanNotificationInfo;
@@ -117,6 +118,7 @@ import org.apache.tomcat.JarScanner;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.modeler.Registry;
import org.apache.tomcat.util.scan.StandardJarScanner;
+import org.apache.tomcat.util.threads.DedicatedThreadExecutor;
/**
* Standard implementation of the <b>Context</b> interface. Each
@@ -4966,6 +4968,7 @@ public class StandardContext extends Con
}
}
+ DedicatedThreadExecutor temporaryExecutor = new
DedicatedThreadExecutor();
try {
// Create context attributes that will be required
@@ -4992,7 +4995,21 @@ public class StandardContext extends Con
// Configure and call application event listeners
if (ok) {
- if (!listenerStart()) {
+ // we do it in a dedicated thread for memory leak protection,
in
+ // case the Listeners registers some ThreadLocals that they
+ // forget to cleanup
+ Boolean listenerStarted =
+ temporaryExecutor.execute(new Callable<Boolean>() {
+ public Boolean call() throws Exception {
+ ClassLoader old = bindThread();
+ try {
+ return listenerStart();
+ } finally {
+ unbindThread(old);
+ }
+ }
+ });
+ if (!listenerStarted) {
log.error( "Error listenerStart");
ok = false;
}
@@ -5013,20 +5030,48 @@ public class StandardContext extends Con
// Configure and call application filters
if (ok) {
- if (!filterStart()) {
- log.error( "Error filterStart");
+ // we do it in a dedicated thread for memory leak protection,
in
+ // case the Filters register some ThreadLocals that they forget
+ // to cleanup
+ Boolean filterStarted =
+ temporaryExecutor.execute(new Callable<Boolean>() {
+ public Boolean call() throws Exception {
+ ClassLoader old = bindThread();
+ try {
+ return filterStart();
+ } finally {
+ unbindThread(old);
+ }
+ }
+ });
+ if (!filterStarted) {
+ log.error("Error filterStart");
ok = false;
}
}
// Load and initialize all "load on startup" servlets
if (ok) {
- loadOnStartup(findChildren());
+ // we do it in a dedicated thread for memory leak protection,
in
+ // case the Servlets register some ThreadLocals that they
forget
+ // to cleanup
+ temporaryExecutor.execute(new Callable<Void>() {
+ public Void call() throws Exception {
+ ClassLoader old = bindThread();
+ try {
+ loadOnStartup(findChildren());
+ return null;
+ } finally {
+ unbindThread(old);
+ }
+ }
+ });
}
} finally {
// Unbinding thread
unbindThread(oldCCL);
+ temporaryExecutor.shutdown();
}
// Set available status depending upon startup success
@@ -5159,23 +5204,38 @@ public class StandardContext extends Con
try {
// Stop our child containers, if any
- Container[] children = findChildren();
- for (int i = 0; i < children.length; i++) {
- children[i].stop();
- }
-
- // Stop our filters
- filterStop();
-
- // Stop ContainerBackgroundProcessor thread
- super.threadStop();
-
- if ((manager != null) && (manager instanceof Lifecycle)) {
- ((Lifecycle) manager).stop();
- }
-
- // Stop our application listeners
- listenerStop();
+ final Container[] children = findChildren();
+ // we do it in a dedicated thread for memory leak protection, in
+ // case some webapp code registers some ThreadLocals that they
+ // forget to cleanup
+ DedicatedThreadExecutor.executeInOwnThread(
+ new Callable<Void>() {
+ public Void call() throws Exception {
+ ClassLoader old = bindThread();
+ try {
+ for (int i = 0; i < children.length; i++) {
+ children[i].stop();
+ }
+
+ // Stop our filters
+ filterStop();
+
+ // Stop ContainerBackgroundProcessor thread
+ threadStop();
+
+ if ((manager != null) &&
+ (manager instanceof Lifecycle)) {
+ ((Lifecycle) manager).stop();
+ }
+
+ // Stop our application listeners
+ listenerStop();
+ return null;
+ }finally{
+ unbindThread(old);
+ }
+ }
+ });
// Finalize our character set mapper
setCharsetMapper(null);
Added:
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java?rev=1044145&view=auto
==============================================================================
---
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
(added)
+++
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
Thu Dec 9 22:11:27 2010
@@ -0,0 +1,137 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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 org.apache.tomcat.util.threads;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.ThreadFactory;
+
+/**
+ * A utility class to execute a {...@link Callable} in a dedicated thread.
+ * It can be used either with an instance to reuse the same thread for each
call
+ * to {...@link #execute(Callable)} or with the static method
+ * {...@link #executeInOwnThread(Callable)}. When using an instance,
+ * {...@link #shutdown()} must be called when the instance is no longer needed
to
+ * dispose of the dedicated thread.
+ */
+public class DedicatedThreadExecutor {
+ private final SingleThreadFactory singleThreadFactory =
+ new SingleThreadFactory();
+ private final ExecutorService executorService =
+ Executors.newSingleThreadExecutor(singleThreadFactory);
+
+ /**
+ * Executes the given {...@link Callable} with the thread spawned for the
+ * current {...@link DedicatedThreadExecutor} instance, and returns its
result.
+ *
+ * @param <V>
+ * the type of the returned value
+ * @param callable
+ * @return
+ */
+ public <V> V execute(final Callable<V> callable) {
+ final Future<V> futureTask = executorService.submit(callable);
+
+ boolean interrupted = false;
+ V result;
+ while (true) {
+ try {
+ result = futureTask.get();
+ break;
+ } catch (InterruptedException e) {
+ // keep waiting
+ interrupted = true;
+ } catch (ExecutionException e) {
+ throw new RuntimeException(e);
+ }
+ }
+ if (interrupted) {
+ // set interruption status so that the caller may react to it
+ Thread.currentThread().interrupt();
+ }
+ return result;
+ }
+
+ /**
+ * Stops the dedicated thread and waits for its death.
+ */
+ public void shutdown() {
+ executorService.shutdown();
+ if (singleThreadFactory.singleThread != null) {
+ boolean interrupted = false;
+ while (true) {
+ try {
+ singleThreadFactory.singleThread.join();
+ singleThreadFactory.singleThread = null;
+ break;
+ } catch (InterruptedException e) {
+ // keep waiting
+ interrupted = true;
+ }
+ }
+ if (interrupted) {
+ // set interruption status so that the caller may react to it
+ Thread.currentThread().interrupt();
+ }
+ }
+ }
+
+ /**
+ * Executes the given {...@link Callable} in a new thread and returns the
+ * result after the thread is stopped.
+ *
+ * @param <V>
+ * @param callable
+ * @return
+ */
+ public static <V> V executeInOwnThread(
+ final Callable<V> callable) {
+ DedicatedThreadExecutor executor = new DedicatedThreadExecutor();
+ try {
+ return executor.execute(callable);
+ } finally {
+ executor.shutdown();
+ }
+
+ }
+
+ // we use a ThreadFactory so that we can later call Thread.join().
+ // Indeed, calling shutdown() on an ExecutorService will eventually stop
the
+ // thread but it might still be alive when execute() returns (race
+ // condition).
+ // This can lead to false alarms about potential memory leaks because the
+ // thread may have a web application class loader for its context class
+ // loader.
+ private class SingleThreadFactory implements ThreadFactory {
+ private volatile Thread singleThread;
+
+ @Override
+ public Thread newThread(Runnable r) {
+ if (singleThread != null) {
+ throw new IllegalStateException(
+ "should not have been called more than once");
+ }
+ singleThread = new Thread(r);
+ singleThread.setDaemon(true);
+ return singleThread;
+ }
+
+ }
+}
Propchange:
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
------------------------------------------------------------------------------
svn:eol-style = native
Propchange:
tomcat/trunk/java/org/apache/tomcat/util/threads/DedicatedThreadExecutor.java
------------------------------------------------------------------------------
svn:keywords = Author Date Id Revision
Added:
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java?rev=1044145&view=auto
==============================================================================
---
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
(added)
+++
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
Thu Dec 9 22:11:27 2010
@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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 org.apache.tomcat.util.threads;
+
+import java.util.concurrent.Callable;
+
+import junit.framework.TestCase;
+
+public class DedicatedThreadExecutorTest extends TestCase {
+ private Thread dedicatedThread;
+
+ public void testExecute() {
+ final Thread testingThread = Thread.currentThread();
+ DedicatedThreadExecutor executor = new DedicatedThreadExecutor();
+ Long result = executor.execute(new Callable<Long>() {
+ @Override
+ public Long call() throws Exception {
+ dedicatedThread = Thread.currentThread();
+ DedicatedThreadExecutorTest.assertNotSame(testingThread,
+ dedicatedThread);
+ return 123L;
+ }
+ });
+ assertEquals(123, result.longValue());
+
+ //check that the same thread is reused
+ executor.execute(new Callable<Void>() {
+ @Override
+ public Void call() throws Exception {
+ DedicatedThreadExecutorTest.assertSame(dedicatedThread,
+ Thread.currentThread());
+ return null;
+ }
+ });
+
+ executor.shutdown();
+ assertFalse(dedicatedThread.isAlive());
+ }
+
+ public void testExecuteInOwnThread() {
+ final Thread testingThread = Thread.currentThread();
+ Long result =
+ DedicatedThreadExecutor.executeInOwnThread(new Callable<Long>() {
+ @Override
+ public Long call() throws Exception {
+ dedicatedThread = Thread.currentThread();
+ DedicatedThreadExecutorTest.assertNotSame(testingThread,
+ dedicatedThread);
+ return 456L;
+ }
+ });
+ assertEquals(456, result.longValue());
+ assertFalse(dedicatedThread.isAlive());
+ }
+
+}
Propchange:
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
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svn:eol-style = native
Propchange:
tomcat/trunk/test/org/apache/tomcat/util/threads/DedicatedThreadExecutorTest.java
------------------------------------------------------------------------------
svn:keywords = Author Date Id Revision
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