1 /* 2 * Copyright (c) 2001, 2010, 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 #ifndef SHARE_VM_MEMORY_DEFNEWGENERATION_INLINE_HPP 26 #define SHARE_VM_MEMORY_DEFNEWGENERATION_INLINE_HPP 27 28 #include "memory/cardTableRS.hpp" 29 #include "memory/defNewGeneration.hpp" 30 #include "memory/space.hpp" 31 32 // Methods of protected closure types 33 34 template <class T> 35 inline void DefNewGeneration::KeepAliveClosure::do_oop_work(T* p) { 36 #ifdef ASSERT 37 { 38 // We never expect to see a null reference being processed 39 // as a weak reference. 40 assert (!oopDesc::is_null(*p), "expected non-null ref"); 41 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 42 assert (obj->is_oop(), "expected an oop while scanning weak refs"); 43 } 44 #endif // ASSERT 45 46 _cl->do_oop_nv(p); 47 48 // Card marking is trickier for weak refs. 49 // This oop is a 'next' field which was filled in while we 50 // were discovering weak references. While we might not need 51 // to take a special action to keep this reference alive, we 52 // will need to dirty a card as the field was modified. 53 // 54 // Alternatively, we could create a method which iterates through 55 // each generation, allowing them in turn to examine the modified 56 // field. 57 // 58 // We could check that p is also in an older generation, but 59 // dirty cards in the youngest gen are never scanned, so the 60 // extra check probably isn't worthwhile. 61 if (Universe::heap()->is_in_reserved(p)) { 62 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 63 _rs->inline_write_ref_field_gc(p, obj); 64 } 65 } 66 67 template <class T> 68 inline void DefNewGeneration::FastKeepAliveClosure::do_oop_work(T* p) { 69 #ifdef ASSERT 70 { 71 // We never expect to see a null reference being processed 72 // as a weak reference. 73 assert (!oopDesc::is_null(*p), "expected non-null ref"); 74 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 75 assert (obj->is_oop(), "expected an oop while scanning weak refs"); 76 } 77 #endif // ASSERT 78 79 _cl->do_oop_nv(p); 80 81 // Optimized for Defnew generation if it's the youngest generation: 82 // we set a younger_gen card if we have an older->youngest 83 // generation pointer. 84 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 85 if (((HeapWord*)obj < _boundary) && Universe::heap()->is_in_reserved(p)) { 86 _rs->inline_write_ref_field_gc(p, obj); 87 } 88 } 89 90 #endif // SHARE_VM_MEMORY_DEFNEWGENERATION_INLINE_HPP