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/workerThread.hpp"
28 #include "gc/shared/workerUtils.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/atomic.hpp"
33 #include "utilities/macros.hpp"
34
35 void PreservedMarks::restore() {
36 while (!_stack.is_empty()) {
37 const PreservedMark elem = _stack.pop();
38 elem.set_mark();
39 }
40 assert_empty();
41 }
42
43 void PreservedMarks::adjust_preserved_mark(PreservedMark* elem) {
44 oop obj = elem->get_oop();
45 if (obj->is_forwarded()) {
46 elem->set_oop(obj->forwardee());
47 }
48 }
49
50 void PreservedMarks::adjust_during_full_gc() {
51 StackIterator<PreservedMark, mtGC> iter(_stack);
52 while (!iter.is_empty()) {
53 PreservedMark* elem = iter.next_addr();
54 adjust_preserved_mark(elem);
55 }
56 }
57
58 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
59 const size_t stack_size = size();
60 restore();
61 // Only do the atomic add if the size is > 0.
62 if (stack_size > 0) {
63 Atomic::add(total_size_addr, stack_size);
64 }
65 }
66
67 #ifndef PRODUCT
68 void PreservedMarks::assert_empty() {
69 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
70 _stack.size());
71 assert(_stack.cache_size() == 0,
72 "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
73 _stack.cache_size());
74 }
75 #endif // ndef PRODUCT
76
77 void PreservedMarksSet::init(uint num) {
78 assert(_stacks == nullptr && _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 RestorePreservedMarksTask : public WorkerTask {
94 PreservedMarksSet* const _preserved_marks_set;
95 SequentialSubTasksDone _sub_tasks;
96 volatile size_t _total_size;
97 #ifdef ASSERT
98 size_t _total_size_before;
99 #endif // ASSERT
100
101 public:
102 void work(uint worker_id) override {
103 uint task_id = 0;
104 while (_sub_tasks.try_claim_task(task_id)) {
105 _preserved_marks_set->get(task_id)->restore_and_increment(&_total_size);
106 }
107 }
108
109 RestorePreservedMarksTask(PreservedMarksSet* preserved_marks_set)
110 : WorkerTask("Restore Preserved Marks"),
111 _preserved_marks_set(preserved_marks_set),
112 _sub_tasks(preserved_marks_set->num()),
113 _total_size(0)
114 DEBUG_ONLY(COMMA _total_size_before(0)) {
115 #ifdef ASSERT
116 // This is to make sure the total_size we'll calculate below is correct.
117 for (uint i = 0; i < _preserved_marks_set->num(); ++i) {
118 _total_size_before += _preserved_marks_set->get(i)->size();
119 }
120 #endif // ASSERT
121 }
122
123 ~RestorePreservedMarksTask() {
124 assert(_total_size == _total_size_before, "total_size = %zu before = %zu", _total_size, _total_size_before);
125 size_t mem_size = _total_size * (sizeof(oop) + sizeof(markWord));
126 log_trace(gc)("Restored %zu marks, occupying %zu %s", _total_size,
127 byte_size_in_proper_unit(mem_size),
128 proper_unit_for_byte_size(mem_size));
129 }
130 };
131
132 void PreservedMarksSet::restore(WorkerThreads* 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 WorkerTask* 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