1 /* 2 * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.gc.shared; 26 27 import java.io.*; 28 import java.util.*; 29 import sun.jvm.hotspot.debugger.*; 30 import sun.jvm.hotspot.memory.*; 31 import sun.jvm.hotspot.runtime.*; 32 import sun.jvm.hotspot.types.*; 33 34 /** <P> A Space describes a heap area. Class Space is an abstract base 35 class. </P> 36 37 <P> Space supports allocation, size computation and GC support is 38 provided. </P> 39 40 <P> Invariant: bottom() and end() are on page_size boundaries and: </P> 41 42 <P> bottom() <= top() <= end() </P> 43 44 <P> top() is inclusive and end() is exclusive. </P> */ 45 46 public abstract class Space extends VMObject { 47 private static AddressField bottomField; 48 private static AddressField endField; 49 50 static { 51 VM.registerVMInitializedObserver(new Observer() { 52 public void update(Observable o, Object data) { 53 initialize(VM.getVM().getTypeDataBase()); 54 } 55 }); 56 } 57 58 private static synchronized void initialize(TypeDataBase db) { 59 Type type = db.lookupType("Space"); 60 61 bottomField = type.getAddressField("_bottom"); 62 endField = type.getAddressField("_end"); 63 } 64 65 public Space(Address addr) { 66 super(addr); 67 } 68 69 public Address bottom() { return bottomField.getValue(addr); } 70 public Address end() { return endField.getValue(addr); } 71 72 /** Returns a subregion of the space containing all the objects in 73 the space. */ 74 public MemRegion usedRegion() { 75 return new MemRegion(bottom(), end()); 76 } 77 78 /** Support for iteration over heap -- not sure how this will 79 interact with GC in reflective system, but necessary for the 80 debugging mechanism */ 81 public OopHandle bottomAsOopHandle() { 82 return bottomField.getOopHandle(addr); 83 } 84 85 /** Support for iteration over heap -- not sure how this will 86 interact with GC in reflective system, but necessary for the 87 debugging mechanism */ 88 public OopHandle nextOopHandle(OopHandle handle, long size) { 89 return handle.addOffsetToAsOopHandle(size); 90 } 91 92 /** Returned value is in bytes */ 93 public long capacity() { return end().minus(bottom()); } 94 /** Returned value is in bytes */ 95 public abstract long used(); 96 /** Returned value is in bytes */ 97 public abstract long free(); 98 99 /** Testers */ 100 public boolean contains(Address p) { 101 return (bottom().lessThanOrEqual(p) && end().greaterThan(p)); 102 } 103 104 public void print() { printOn(System.out); } 105 public void printOn(PrintStream tty) { 106 tty.print(" space capacity = "); 107 tty.print(capacity()); 108 tty.print(", "); 109 tty.print((double) used() * 100.0/ capacity()); 110 tty.print(" used"); 111 } 112 }