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8022321: java/lang/ref/OOMEInReferenceHandler.java fails intermittently

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Preload/preinitialize InterruptedException and Cleaner classes and catch OOME from instanceof operator in ReferenceHandler

Reviewed-by: dholmes, mchung, srikchan
This commit is contained in:
Peter Levart 2014-01-30 15:36:04 +01:00
parent ba68b878a0
commit 91796b96b9
1 changed files with 47 additions and 28 deletions
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59
jdk/src/share/classes/java/lang/ref/Reference.java
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@ -111,7 +111,7 @@ public abstract class Reference<T> {
* therefore critical that any code holding this lock complete as quickly
* as possible, allocate no new objects, and avoid calling user code.
*/
static private class Lock { };
static private class Lock { }
private static Lock lock = new Lock();
@ -126,6 +126,22 @@ public abstract class Reference<T> {
*/
private static class ReferenceHandler extends Thread {
private static void ensureClassInitialized(Class<?> clazz) {
try {
Class.forName(clazz.getName(), true, clazz.getClassLoader());
} catch (ClassNotFoundException e) {
throw (Error) new NoClassDefFoundError(e.getMessage()).initCause(e);
}
}
static {
// pre-load and initialize InterruptedException and Cleaner classes
// so that we don't get into trouble later in the run loop if there's
// memory shortage while loading/initializing them lazily.
ensureClassInitialized(InterruptedException.class);
ensureClassInitialized(Cleaner.class);
}
ReferenceHandler(ThreadGroup g, String name) {
super(g, name);
}
@ -133,37 +149,40 @@ public abstract class Reference<T> {
public void run() {
for (;;) {
Reference<Object> r;
Cleaner c;
try {
synchronized (lock) {
if (pending != null) {
r = pending;
// 'instanceof' might throw OutOfMemoryError sometimes
// so do this before un-linking 'r' from the 'pending' chain...
c = r instanceof Cleaner ? (Cleaner) r : null;
// unlink 'r' from 'pending' chain
pending = r.discovered;
r.discovered = null;
} else {
// The waiting on the lock may cause an OOME because it may try to allocate
// exception objects, so also catch OOME here to avoid silent exit of the
// reference handler thread.
//
// Explicitly define the order of the two exceptions we catch here
// when waiting for the lock.
//
// We do not want to try to potentially load the InterruptedException class
// (which would be done if this was its first use, and InterruptedException
// were checked first) in this situation.
//
// This may lead to the VM not ever trying to load the InterruptedException
// class again.
try {
try {
// The waiting on the lock may cause an OutOfMemoryError
// because it may try to allocate exception objects.
lock.wait();
} catch (OutOfMemoryError x) { }
} catch (InterruptedException x) { }
continue;
}
}
} catch (OutOfMemoryError x) {
// Give other threads CPU time so they hopefully drop some live references
// and GC reclaims some space.
// Also prevent CPU intensive spinning in case 'r instanceof Cleaner' above
// persistently throws OOME for some time...
Thread.yield();
// retry
continue;
} catch (InterruptedException x) {
// retry
continue;
}
// Fast path for cleaners
if (r instanceof Cleaner) {
((Cleaner)r).clean();
if (c != null) {
c.clean();
continue;
}