1 /*
2 * Copyright (c) 2016, 2017, 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::adjust_during_full_gc() {
41 StackIterator<OopAndMarkOop, mtGC> iter(_stack);
42 while (!iter.is_empty()) {
43 OopAndMarkOop* elem = iter.next_addr();
44
45 oop obj = elem->get_oop();
46 if (obj->is_forwarded()) {
47 elem->set_oop(obj->forwardee());
48 }
49 }
50 }
51
52 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
53 const size_t stack_size = size();
54 restore();
55 // Only do the atomic add if the size is > 0.
56 if (stack_size > 0) {
57 Atomic::add(stack_size, total_size_addr);
58 }
59 }
60
61 #ifndef PRODUCT
62 void PreservedMarks::assert_empty() {
63 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
64 _stack.size());
65 assert(_stack.cache_size() == 0,
66 "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
67 _stack.cache_size());
68 }
69 #endif // ndef PRODUCT
70
71 void RemoveForwardedPointerClosure::do_object(oop obj) {
72 if (obj->is_forwarded()) {
73 PreservedMarks::init_forwarded_mark(obj);
74 }
75 }
76
77 void PreservedMarksSet::init(uint num) {
78 assert(_stacks == NULL && _num == 0, "do not re-initialize");
79 assert(num > 0, "pre-condition");
80 if (_in_c_heap) {
81 _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
82 } else {
83 _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
84 }
85 for (uint i = 0; i < num; i += 1) {
86 ::new (_stacks + i) PreservedMarks();
87 }
88 _num = num;
89
90 assert_empty();
91 }
92
93 class ParRestoreTask : public AbstractGangTask {
94 private:
95 PreservedMarksSet* const _preserved_marks_set;
96 SequentialSubTasksDone _sub_tasks;
97 volatile size_t* const _total_size_addr;
98
99 public:
100 virtual void work(uint worker_id) {
101 uint task_id = 0;
102 while (!_sub_tasks.is_task_claimed(/* reference */ task_id)) {
103 _preserved_marks_set->get(task_id)->restore_and_increment(_total_size_addr);
104 }
105 _sub_tasks.all_tasks_completed();
106 }
107
108 ParRestoreTask(uint worker_num,
109 PreservedMarksSet* preserved_marks_set,
110 volatile size_t* total_size_addr)
111 : AbstractGangTask("Parallel Preserved Mark Restoration"),
112 _preserved_marks_set(preserved_marks_set),
113 _total_size_addr(total_size_addr) {
114 _sub_tasks.set_n_threads(worker_num);
115 _sub_tasks.set_n_tasks(preserved_marks_set->num());
116 }
117 };
118
119 void PreservedMarksSet::reclaim() {
120 assert_empty();
121
122 for (uint i = 0; i < _num; i += 1) {
123 _stacks[i].~Padded<PreservedMarks>();
124 }
125
126 if (_in_c_heap) {
127 FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
128 } else {
129 // the array was resource-allocated, so nothing to do
130 }
131 _stacks = NULL;
132 _num = 0;
133 }
134
135 #ifndef PRODUCT
136 void PreservedMarksSet::assert_empty() {
137 assert(_stacks != NULL && _num > 0, "should have been initialized");
138 for (uint i = 0; i < _num; i += 1) {
139 get(i)->assert_empty();
140 }
141 }
142 #endif // ndef PRODUCT
143
144 void SharedRestorePreservedMarksTaskExecutor::restore(PreservedMarksSet* preserved_marks_set,
145 volatile size_t* total_size_addr) {
146 if (_workers == NULL) {
147 for (uint i = 0; i < preserved_marks_set->num(); i += 1) {
148 *total_size_addr += preserved_marks_set->get(i)->size();
149 preserved_marks_set->get(i)->restore();
150 }
151 } else {
152 ParRestoreTask task(_workers->active_workers(), preserved_marks_set, total_size_addr);
153 _workers->run_task(&task);
154 }
155 }