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