1 /*
2 * Copyright (c) 2016, 2021, 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 "oops/oop.inline.hpp"
31 #include "runtime/atomic.hpp"
32 #include "utilities/macros.hpp"
33
34 void PreservedMarks::restore() {
35 while (!_stack.is_empty()) {
36 const OopAndMarkWord elem = _stack.pop();
37 elem.set_mark();
38 }
39 assert_empty();
40 }
41
42 void PreservedMarks::adjust_during_full_gc() {
43 StackIterator<OopAndMarkWord, mtGC> iter(_stack);
44 while (!iter.is_empty()) {
45 OopAndMarkWord* elem = iter.next_addr();
46
47 oop obj = elem->get_oop();
48 if (obj->is_forwarded()) {
49 elem->set_oop(obj->forwardee());
50 }
51 }
52 }
53
54 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
55 const size_t stack_size = size();
56 restore();
57 // Only do the atomic add if the size is > 0.
58 if (stack_size > 0) {
59 Atomic::add(total_size_addr, stack_size);
60 }
61 }
62
63 #ifndef PRODUCT
64 void PreservedMarks::assert_empty() {
65 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
66 _stack.size());
67 assert(_stack.cache_size() == 0,
68 "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
69 _stack.cache_size());
70 }
71 #endif // ndef PRODUCT
72
73 void RemoveForwardedPointerClosure::do_object(oop obj) {
74 if (obj->is_forwarded()) {
75 PreservedMarks::init_forwarded_mark(obj);
76 }
77 }
78
79 void PreservedMarksSet::init(uint num) {
80 assert(_stacks == nullptr && _num == 0, "do not re-initialize");
81 assert(num > 0, "pre-condition");
82 if (_in_c_heap) {
83 _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
84 } else {
85 _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
86 }
87 for (uint i = 0; i < num; i += 1) {
88 ::new (_stacks + i) PreservedMarks();
89 }
90 _num = num;
91
92 assert_empty();
93 }
94
95 class RestorePreservedMarksTask : public AbstractGangTask {
96 PreservedMarksSet* const _preserved_marks_set;
97 SequentialSubTasksDone _sub_tasks;
98 volatile size_t _total_size;
99 #ifdef ASSERT
100 size_t _total_size_before;
101 #endif // ASSERT
102
103 public:
104 void work(uint worker_id) override {
105 uint task_id = 0;
106 while (_sub_tasks.try_claim_task(task_id)) {
107 _preserved_marks_set->get(task_id)->restore_and_increment(&_total_size);
108 }
109 }
110
111 RestorePreservedMarksTask(PreservedMarksSet* preserved_marks_set)
112 : AbstractGangTask("Restore Preserved Marks"),
113 _preserved_marks_set(preserved_marks_set),
114 _sub_tasks(preserved_marks_set->num()),
115 _total_size(0)
116 DEBUG_ONLY(COMMA _total_size_before(0)) {
117 #ifdef ASSERT
118 // This is to make sure the total_size we'll calculate below is correct.
119 for (uint i = 0; i < _preserved_marks_set->num(); ++i) {
120 _total_size_before += _preserved_marks_set->get(i)->size();
121 }
122 #endif // ASSERT
123 }
124
125 ~RestorePreservedMarksTask() {
126 assert(_total_size == _total_size_before, "total_size = %zu before = %zu", _total_size, _total_size_before);
127
128 log_trace(gc)("Restored %zu marks", _total_size);
129 }
130 };
131
132 void PreservedMarksSet::restore(WorkGang* workers) {
133 {
134 RestorePreservedMarksTask cl(this);
135 if (workers == nullptr) {
136 cl.work(0);
137 } else {
138 workers->run_task(&cl);
139 }
140 }
141
142 assert_empty();
143 }
144
145 AbstractGangTask* PreservedMarksSet::create_task() {
146 return new RestorePreservedMarksTask(this);
147 }
148
149 void PreservedMarksSet::reclaim() {
150 assert_empty();
151
152 for (uint i = 0; i < _num; i += 1) {
153 _stacks[i].~Padded<PreservedMarks>();
154 }
155
156 if (_in_c_heap) {
157 FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
158 } else {
159 // the array was resource-allocated, so nothing to do
160 }
161 _stacks = nullptr;
162 _num = 0;
163 }
164
165 #ifndef PRODUCT
166 void PreservedMarksSet::assert_empty() {
167 assert(_stacks != nullptr && _num > 0, "should have been initialized");
168 for (uint i = 0; i < _num; i += 1) {
169 get(i)->assert_empty();
170 }
171 }
172 #endif // ndef PRODUCT
--- EOF ---