1 /* 2 * Copyright (c) 2016, 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 "gc/shared/preservedMarks.inline.hpp" 27 #include "gc/shared/workgroup.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "utilities/macros.hpp" 31 32 void PreservedMarks::restore() { 33 while (!_stack.is_empty()) { 34 const OopAndMarkOop elem = _stack.pop(); 35 elem.set_mark(); 36 } 37 assert_empty(); 38 } 39 40 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) { 41 const size_t stack_size = size(); 42 restore(); 43 // Only do the atomic add if the size is > 0. 44 if (stack_size > 0) { 45 Atomic::add(stack_size, total_size_addr); 46 } 47 } 48 49 #ifndef PRODUCT 50 void PreservedMarks::assert_empty() { 51 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT, 52 _stack.size()); 53 assert(_stack.cache_size() == 0, 54 "stack expected to have no cached segments, cache size = " SIZE_FORMAT, 55 _stack.cache_size()); 56 } 57 #endif // ndef PRODUCT 58 59 void RemoveForwardedPointerClosure::do_object(oop obj) { 60 if (obj->is_forwarded()) { 61 PreservedMarks::init_forwarded_mark(obj); 62 } 63 } 64 65 void PreservedMarksSet::init(uint num) { 66 assert(_stacks == NULL && _num == 0, "do not re-initialize"); 67 assert(num > 0, "pre-condition"); 68 if (_in_c_heap) { 69 _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC); 70 } else { 71 _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num); 72 } 73 for (uint i = 0; i < num; i += 1) { 74 ::new (_stacks + i) PreservedMarks(); 75 } 76 _num = num; 77 78 assert_empty(); 79 } 80 81 class ParRestoreTask : public AbstractGangTask { 82 private: 83 PreservedMarksSet* const _preserved_marks_set; 84 SequentialSubTasksDone _sub_tasks; 85 volatile size_t* const _total_size_addr; 86 87 public: 88 virtual void work(uint worker_id) { 89 uint task_id = 0; 90 while (!_sub_tasks.is_task_claimed(/* reference */ task_id)) { 91 _preserved_marks_set->get(task_id)->restore_and_increment(_total_size_addr); 92 } 93 _sub_tasks.all_tasks_completed(); 94 } 95 96 ParRestoreTask(uint worker_num, 97 PreservedMarksSet* preserved_marks_set, 98 volatile size_t* total_size_addr) 99 : AbstractGangTask("Parallel Preserved Mark Restoration"), 100 _preserved_marks_set(preserved_marks_set), 101 _total_size_addr(total_size_addr) { 102 _sub_tasks.set_n_threads(worker_num); 103 _sub_tasks.set_n_tasks(preserved_marks_set->num()); 104 } 105 }; 106 107 108 void PreservedMarksSet::reclaim() { 109 assert_empty(); 110 111 for (uint i = 0; i < _num; i += 1) { 112 _stacks[i].~Padded<PreservedMarks>(); 113 } 114 115 if (_in_c_heap) { 116 FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks); 117 } else { 118 // the array was resource-allocated, so nothing to do 119 } 120 _stacks = NULL; 121 _num = 0; 122 } 123 124 #ifndef PRODUCT 125 void PreservedMarksSet::assert_empty() { 126 assert(_stacks != NULL && _num > 0, "should have been initialized"); 127 for (uint i = 0; i < _num; i += 1) { 128 get(i)->assert_empty(); 129 } 130 } 131 #endif // ndef PRODUCT 132 133 void SharedRestorePreservedMarksTaskExecutor::restore(PreservedMarksSet* preserved_marks_set, 134 volatile size_t* total_size_addr) { 135 if (_workers == NULL) { 136 for (uint i = 0; i < preserved_marks_set->num(); i += 1) { 137 *total_size_addr += preserved_marks_set->get(i)->size(); 138 preserved_marks_set->get(i)->restore(); 139 } 140 } else { 141 ParRestoreTask task(_workers->active_workers(), preserved_marks_set, total_size_addr); 142 _workers->run_task(&task); 143 } 144 }