1 /* 2 * Copyright (c) 2001, 2013, 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 #include "precompiled.hpp" 26 #include "classfile/classLoaderData.hpp" 27 #include "memory/cardTableRS.hpp" 28 #include "memory/genRemSet.hpp" 29 #include "oops/klass.hpp" 30 31 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and 32 // enumerate ref fields that have been modified (since the last 33 // enumeration.) 34 35 uintx GenRemSet::max_alignment_constraint() { 36 return CardTableRS::ct_max_alignment_constraint(); 37 } 38 39 class HasAccumulatedModifiedOopsClosure : public KlassClosure { 40 bool _found; 41 public: 42 HasAccumulatedModifiedOopsClosure() : _found(false) {} 43 void do_klass(Klass* klass) { 44 if (_found) { 45 return; 46 } 47 48 if (klass->has_accumulated_modified_oops()) { 49 _found = true; 50 } 51 } 52 bool found() { 53 return _found; 54 } 55 }; 56 57 bool KlassRemSet::mod_union_is_clear() { 58 HasAccumulatedModifiedOopsClosure closure; 59 ClassLoaderDataGraph::classes_do(&closure); 60 61 return !closure.found(); 62 } 63 64 65 class ClearKlassModUnionClosure : public KlassClosure { 66 public: 67 void do_klass(Klass* klass) { 68 if (klass->has_accumulated_modified_oops()) { 69 klass->clear_accumulated_modified_oops(); 70 } 71 } 72 }; 73 74 void KlassRemSet::clear_mod_union() { 75 ClearKlassModUnionClosure closure; 76 ClassLoaderDataGraph::classes_do(&closure); 77 }