Mercurial > hg > truffle
view agent/src/share/classes/sun/jvm/hotspot/tools/FinalizerInfo.java @ 19491:4d66c000d253
Truffle/Instrumentation: more cleanup in Probe
author | Michael Van De Vanter <michael.van.de.vanter@oracle.com> |
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date | Wed, 18 Feb 2015 18:30:49 -0800 |
parents | 89152779163c |
children |
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/* * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ package sun.jvm.hotspot.tools; import sun.jvm.hotspot.debugger.JVMDebugger; import sun.jvm.hotspot.tools.*; import sun.jvm.hotspot.oops.*; import sun.jvm.hotspot.runtime.VM; import sun.jvm.hotspot.utilities.SystemDictionaryHelper; import sun.jvm.hotspot.utilities.ObjectReader; import sun.jvm.hotspot.utilities.MarkBits; import java.util.HashMap; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; /* * Iterates over the queue of object pending finalization and prints a * summary of these objects in the form of a histogram. */ public class FinalizerInfo extends Tool { public FinalizerInfo() { super(); } public FinalizerInfo(JVMDebugger d) { super(d); } public static void main(String[] args) { FinalizerInfo finfo = new FinalizerInfo(); finfo.execute(args); } public void run() { /* * The implementation here has a dependency on the implementation of * java.lang.ref.Finalizer. If the Finalizer implementation changes it's * possible this method will require changes too. We looked into using * ObjectReader to deserialize the objects from the target VM but as * there aren't any public methods to traverse the queue it means using * reflection which will also tie us to the implementation. * * The assumption here is that Finalizer.queue is the ReferenceQueue * with the objects awaiting finalization. The ReferenceQueue queueLength * is the number of objects in the queue, and 'head' is the head of the * queue. */ InstanceKlass ik = SystemDictionaryHelper.findInstanceKlass("java.lang.ref.Finalizer"); final Oop[] queueref = new Oop[1]; ik.iterateStaticFields(new DefaultOopVisitor() { public void doOop(OopField field, boolean isVMField) { String name = field.getID().getName(); if (name.equals("queue")) { queueref[0] = field.getValue(getObj()); } } }); Oop queue = queueref[0]; InstanceKlass k = (InstanceKlass) queue.getKlass(); LongField queueLengthField = (LongField) k.findField("queueLength", "J"); long queueLength = queueLengthField.getValue(queue); OopField headField = (OopField) k.findField("head", "Ljava/lang/ref/Reference;"); Oop head = headField.getValue(queue); System.out.println("Number of objects pending for finalization: " + queueLength); /* * If 'head' is non-NULL then it is the head of a list of References. * We iterate over the list (end of list is when head.next == head) */ if (head != null) { k = (InstanceKlass) head.getKlass(); OopField referentField = (OopField) k.findField("referent", "Ljava/lang/Object;"); OopField nextField = (OopField) k.findField("next", "Ljava/lang/ref/Reference;"); HashMap map = new HashMap(); for (;;) { Oop referent = referentField.getValue(head); Klass klass = referent.getKlass(); if (!map.containsKey(klass)) { map.put(klass, new ObjectHistogramElement(klass)); } ((ObjectHistogramElement)map.get(klass)).updateWith(referent); Oop next = nextField.getValue(head); if (next == null || next.equals(head)) break; head = next; } /* * Sort results - decending order by total size */ ArrayList list = new ArrayList(); list.addAll(map.values()); Collections.sort(list, new Comparator() { public int compare(Object o1, Object o2) { return ((ObjectHistogramElement)o1).compare((ObjectHistogramElement)o2); } }); /* * Print summary of objects in queue */ System.out.println(""); System.out.println("Count" + "\t" + "Class description"); System.out.println("-------------------------------------------------------"); for (int i=0; i<list.size(); i++) { ObjectHistogramElement e = (ObjectHistogramElement)list.get(i); System.out.println(e.getCount() + "\t" + e.getDescription()); } } } }