1 /*
2 * Copyright (c) 2016, 2023, 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 OopAndMarkWord elem = _stack.pop();
39 elem.set_mark();
40 }
41 assert_empty();
42 }
43
44 template <bool ALT_FWD>
45 void PreservedMarks::adjust_during_full_gc_impl() {
46 StackIterator<OopAndMarkWord, mtGC> iter(_stack);
47 while (!iter.is_empty()) {
48 OopAndMarkWord* elem = iter.next_addr();
49
50 oop obj = elem->get_oop();
51 if (obj->is_forwarded()) {
52 elem->set_oop(SlidingForwarding::forwardee<ALT_FWD>(obj));
53 }
54 }
55 }
56
57 void PreservedMarks::adjust_during_full_gc() {
58 if (UseAltGCForwarding) {
59 adjust_during_full_gc_impl<true>();
60 } else {
61 adjust_during_full_gc_impl<false>();
62 }
63 }
64
65 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
66 const size_t stack_size = size();
67 restore();
68 // Only do the atomic add if the size is > 0.
69 if (stack_size > 0) {
70 Atomic::add(total_size_addr, stack_size);
71 }
72 }
73
74 #ifndef PRODUCT
75 void PreservedMarks::assert_empty() {
76 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
77 _stack.size());
78 assert(_stack.cache_size() == 0,
79 "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
80 _stack.cache_size());
81 }
82 #endif // ndef PRODUCT
83
84 void PreservedMarksSet::init(uint num) {
85 assert(_stacks == nullptr && _num == 0, "do not re-initialize");
86 assert(num > 0, "pre-condition");
87 if (_in_c_heap) {
88 _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
89 } else {
90 _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
91 }
92 for (uint i = 0; i < num; i += 1) {
93 ::new (_stacks + i) PreservedMarks();
94 }
95 _num = num;
96
97 assert_empty();
98 }
99
100 class RestorePreservedMarksTask : public WorkerTask {
101 PreservedMarksSet* const _preserved_marks_set;
102 SequentialSubTasksDone _sub_tasks;
103 volatile size_t _total_size;
104 #ifdef ASSERT
105 size_t _total_size_before;
106 #endif // ASSERT
107
108 public:
109 void work(uint worker_id) override {
110 uint task_id = 0;
111 while (_sub_tasks.try_claim_task(task_id)) {
112 _preserved_marks_set->get(task_id)->restore_and_increment(&_total_size);
113 }
114 }
115
116 RestorePreservedMarksTask(PreservedMarksSet* preserved_marks_set)
117 : WorkerTask("Restore Preserved Marks"),
118 _preserved_marks_set(preserved_marks_set),
119 _sub_tasks(preserved_marks_set->num()),
120 _total_size(0)
121 DEBUG_ONLY(COMMA _total_size_before(0)) {
122 #ifdef ASSERT
123 // This is to make sure the total_size we'll calculate below is correct.
124 for (uint i = 0; i < _preserved_marks_set->num(); ++i) {
125 _total_size_before += _preserved_marks_set->get(i)->size();
126 }
127 #endif // ASSERT
128 }
129
130 ~RestorePreservedMarksTask() {
131 assert(_total_size == _total_size_before, "total_size = %zu before = %zu", _total_size, _total_size_before);
132 size_t mem_size = _total_size * (sizeof(oop) + sizeof(markWord));
133 log_trace(gc)("Restored %zu marks, occupying %zu %s", _total_size,
134 byte_size_in_proper_unit(mem_size),
135 proper_unit_for_byte_size(mem_size));
136 }
137 };
138
139 void PreservedMarksSet::restore(WorkerThreads* workers) {
140 {
141 RestorePreservedMarksTask cl(this);
142 if (workers == nullptr) {
143 cl.work(0);
144 } else {
145 workers->run_task(&cl);
146 }
147 }
148
149 assert_empty();
150 }
151
152 WorkerTask* PreservedMarksSet::create_task() {
153 return new RestorePreservedMarksTask(this);
154 }
155
156 void PreservedMarksSet::reclaim() {
157 assert_empty();
158
159 for (uint i = 0; i < _num; i += 1) {
160 _stacks[i].~Padded<PreservedMarks>();
161 }
162
163 if (_in_c_heap) {
164 FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
165 } else {
166 // the array was resource-allocated, so nothing to do
167 }
168 _stacks = nullptr;
169 _num = 0;
170 }
171
172 #ifndef PRODUCT
173 void PreservedMarksSet::assert_empty() {
174 assert(_stacks != nullptr && _num > 0, "should have been initialized");
175 for (uint i = 0; i < _num; i += 1) {
176 get(i)->assert_empty();
177 }
178 }
179 #endif // ndef PRODUCT