Mercurial > hg > truffle
view test/compiler/7190310/Test7190310_unsafe.java @ 10246:194f52aa2f23
7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap
Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich.
Reviewed-by: tschatzl, jmasa
author | johnc |
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date | Thu, 09 May 2013 11:16:39 -0700 |
parents | 09aad8452938 |
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/* * Copyright (c) 2012, 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. * */ /* * @test * @bug 7190310 * @summary Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops * @run main/othervm -Xbatch Test7190310_unsafe */ import java.lang.ref.*; import java.lang.reflect.*; import sun.misc.Unsafe; public class Test7190310_unsafe { static class TestObject { public String toString() { return "TestObject"; } }; private static TestObject str = new TestObject(); private static final WeakReference ref = new WeakReference(str); private TestObject obj; public static void main(String[] args) throws Exception { Class c = Test7190310_unsafe.class.getClassLoader().loadClass("sun.misc.Unsafe"); Field f = c.getDeclaredField("theUnsafe"); f.setAccessible(true); Unsafe unsafe = (Unsafe)f.get(c); f = Reference.class.getDeclaredField("referent"); f.setAccessible(true); long referent_offset = unsafe.objectFieldOffset(f); Test7190310_unsafe t = new Test7190310_unsafe(); TestObject o = new TestObject(); t.obj = o; // Warmup (compile methods) System.err.println("Warmup"); Object obj = null; for (int i = 0; i < 11000; i++) { obj = getRef0(ref); } for (int i = 0; i < 11000; i++) { obj = getRef1(unsafe, ref, referent_offset); } for (int i = 0; i < 11000; i++) { obj = getRef2(unsafe, ref, referent_offset); } for (int i = 0; i < 11000; i++) { obj = getRef3(unsafe, ref, referent_offset); } for (int i = 0; i < 11000; i++) { obj = getRef4(unsafe, t, referent_offset); } // Access verification System.err.println("Verification"); if (!verifyGet(referent_offset, unsafe)) { System.exit(97); } obj = getRef3(unsafe, t, referent_offset); if (obj != o) { System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + o); System.exit(97); } obj = getRef4(unsafe, t, referent_offset); if (obj != o) { System.out.println("FAILED: unsafe.getObject(Test7190310, " + referent_offset + ") " + obj + " != " + o); System.exit(97); } } static boolean verifyGet(long referent_offset, Unsafe unsafe) throws Exception { // Access verification System.out.println("referent: " + str); Object obj = getRef0(ref); if (obj != str) { System.out.println("FAILED: weakRef.get() " + obj + " != " + str); return false; } obj = getRef1(unsafe, ref, referent_offset); if (obj != str) { System.out.println("FAILED: unsafe.getObject(weakRef, " + referent_offset + ") " + obj + " != " + str); return false; } obj = getRef2(unsafe, ref, referent_offset); if (obj != str) { System.out.println("FAILED: unsafe.getObject(abstRef, " + referent_offset + ") " + obj + " != " + str); return false; } obj = getRef3(unsafe, ref, referent_offset); if (obj != str) { System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + str); return false; } return true; } static Object getRef0(WeakReference ref) throws Exception { return ref.get(); } static Object getRef1(Unsafe unsafe, WeakReference ref, long referent_offset) throws Exception { return unsafe.getObject(ref, referent_offset); } static Object getRef2(Unsafe unsafe, Reference ref, long referent_offset) throws Exception { return unsafe.getObject(ref, referent_offset); } static Object getRef3(Unsafe unsafe, Object ref, long referent_offset) throws Exception { return unsafe.getObject(ref, referent_offset); } static Object getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset) throws Exception { return unsafe.getObject(ref, referent_offset); } }