1 /*
2 * Copyright (c) 2016, 2018, 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 "utilities/macros.hpp"
32
33 void PreservedMarks::restore() {
34 while (!_stack.is_empty()) {
35 const OopAndMarkWord elem = _stack.pop();
36 elem.set_mark();
37 }
38 assert_empty();
39 }
40
41 void PreservedMarks::adjust_during_full_gc() {
42 StackIterator<OopAndMarkWord, mtGC> iter(_stack);
43 while (!iter.is_empty()) {
44 OopAndMarkWord* elem = iter.next_addr();
45
46 oop obj = elem->get_oop();
47 if (obj->is_forwarded()) {
48 elem->set_oop(obj->forwardee());
49 }
50 }
51 }
52
53 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
54 const size_t stack_size = size();
55 restore();
56 // Only do the atomic add if the size is > 0.
57 if (stack_size > 0) {
58 Atomic::add(stack_size, total_size_addr);
59 }
60 }
61
62 #ifndef PRODUCT
63 void PreservedMarks::assert_empty() {
64 assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
65 _stack.size());
66 assert(_stack.cache_size() == 0,
67 "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
68 _stack.cache_size());
69 }
70 #endif // ndef PRODUCT
71
72 void RemoveForwardedPointerClosure::do_object(oop obj) {
73 if (obj->is_forwarded()) {
74 PreservedMarks::init_forwarded_mark(obj);
75 }
76 }
77
78 void PreservedMarksSet::init(uint num) {
79 assert(_stacks == NULL && _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 ParRestoreTask : public AbstractGangTask {
95 private:
96 PreservedMarksSet* const _preserved_marks_set;
97 SequentialSubTasksDone _sub_tasks;
98 volatile size_t* const _total_size_addr;
99
100 public:
101 virtual void work(uint worker_id) {
102 uint task_id = 0;
103 while (_sub_tasks.try_claim_task(/* reference */ task_id)) {
104 _preserved_marks_set->get(task_id)->restore_and_increment(_total_size_addr);
105 }
106 _sub_tasks.all_tasks_completed();
107 }
108
109 ParRestoreTask(uint worker_num,
110 PreservedMarksSet* preserved_marks_set,
111 volatile size_t* total_size_addr)
112 : AbstractGangTask("Parallel Preserved Mark Restoration"),
113 _preserved_marks_set(preserved_marks_set),
114 _total_size_addr(total_size_addr) {
115 _sub_tasks.set_n_threads(worker_num);
116 _sub_tasks.set_n_tasks(preserved_marks_set->num());
117 }
118 };
119
120 void PreservedMarksSet::reclaim() {
121 assert_empty();
122
123 for (uint i = 0; i < _num; i += 1) {
124 _stacks[i].~Padded<PreservedMarks>();
125 }
126
127 if (_in_c_heap) {
128 FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
129 } else {
130 // the array was resource-allocated, so nothing to do
131 }
132 _stacks = NULL;
133 _num = 0;
134 }
135
136 #ifndef PRODUCT
137 void PreservedMarksSet::assert_empty() {
138 assert(_stacks != NULL && _num > 0, "should have been initialized");
139 for (uint i = 0; i < _num; i += 1) {
140 get(i)->assert_empty();
141 }
142 }
143 #endif // ndef PRODUCT
144
145 void SharedRestorePreservedMarksTaskExecutor::restore(PreservedMarksSet* preserved_marks_set,
146 volatile size_t* total_size_addr) {
147 if (_workers == NULL) {
148 for (uint i = 0; i < preserved_marks_set->num(); i += 1) {
149 *total_size_addr += preserved_marks_set->get(i)->size();
150 preserved_marks_set->get(i)->restore();
151 }
152 } else {
153 ParRestoreTask task(_workers->active_workers(), preserved_marks_set, total_size_addr);
154 _workers->run_task(&task);
155 }
156 }