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