1 /*
2 * Copyright (c) 2016, 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/parallel/gcTaskManager.hpp"
27 #include "gc/shared/preservedMarks.inline.hpp"
28 #include "gc/shared/workgroup.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31
32 void PreservedMarks::restore() {
33 while (!_stack.is_empty()) {
34 const OopAndMarkOop elem = _stack.pop();
35 elem.set_mark();
36 }
37 assert_empty();
38 }
39
40 #ifndef PRODUCT
41 void PreservedMarks::assert_empty() {
42 assert(_stack.is_empty(), "stack expected to be empty, size = "SIZE_FORMAT,
43 _stack.size());
44 assert(_stack.cache_size() == 0,
45 "stack expected to have no cached segments, cache size = "SIZE_FORMAT,
46 _stack.cache_size());
47 }
48 #endif // ndef PRODUCT
49
50 void RemoveForwardedPointerClosure::do_object(oop obj) {
51 if (obj->is_forwarded()) {
52 PreservedMarks::init_forwarded_mark(obj);
53 }
54 }
55
56 void PreservedMarksSet::init(uint num) {
57 assert(_stacks == NULL && _num == 0, "do not re-initialize");
58 assert(num > 0, "pre-condition");
59 if (_in_c_heap) {
60 _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
61 } else {
62 _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
63 }
64 for (uint i = 0; i < num; i += 1) {
65 ::new (_stacks + i) PreservedMarks();
66 }
67 _num = num;
68
69 assert_empty();
70 }
71
72 class ParRestoreTask : public AbstractGangTask {
73 private:
74 PreservedMarksSet* const _preserved_marks_set;
75 SequentialSubTasksDone _sub_tasks;
76 volatile size_t* const _total_size_addr;
77
78 public:
79 virtual void work(uint worker_id) {
80 uint task_id = 0;
81 while (!_sub_tasks.is_task_claimed(/* reference */ task_id)) {
82 PreservedMarks* const preserved_marks = _preserved_marks_set->get(task_id);
83 const size_t size = preserved_marks->size();
84 preserved_marks->restore();
85 // Only do the atomic add if the size is > 0.
86 if (size > 0) {
87 Atomic::add(size, _total_size_addr);
88 }
89 }
90 _sub_tasks.all_tasks_completed();
91 }
92
93 ParRestoreTask(uint worker_num,
94 PreservedMarksSet* preserved_marks_set,
95 volatile size_t* total_size_addr)
96 : AbstractGangTask("Parallel Preserved Mark Restoration"),
97 _preserved_marks_set(preserved_marks_set),
98 _total_size_addr(total_size_addr) {
99 _sub_tasks.set_n_threads(worker_num);
100 _sub_tasks.set_n_tasks(preserved_marks_set->num());
101 }
102 };
103
104 void PreservedMarksSet::restore_internal(WorkGang* workers,
105 volatile size_t* total_size_addr) {
106 assert(workers != NULL, "pre-condition");
107 ParRestoreTask task(workers->active_workers(), this, total_size_addr);
108 workers->run_task(&task);
109 }
110
111 class ParRestoreGCTask : public GCTask {
112 private:
113 const uint _id;
114 PreservedMarksSet* const _preserved_marks_set;
115 volatile size_t* const _total_size_addr;
116
117 public:
118 virtual char* name() { return (char*) "preserved mark restoration task"; }
119
120 virtual void do_it(GCTaskManager* manager, uint which) {
121 PreservedMarks* const preserved_marks = _preserved_marks_set->get(_id);
122 const size_t size = preserved_marks->size();
123 preserved_marks->restore();
124 // Only do the atomic add if the size is > 0.
125 if (size > 0) {
126 Atomic::add(size, _total_size_addr);
127 }
128 }
129
130 ParRestoreGCTask(uint id,
131 PreservedMarksSet* preserved_marks_set,
132 volatile size_t* total_size_addr)
133 : _id(id),
134 _preserved_marks_set(preserved_marks_set),
135 _total_size_addr(total_size_addr) { }
136 };
137
138 void PreservedMarksSet::restore_internal(GCTaskManager* gc_task_manager,
139 volatile size_t* total_size_addr) {
140 // GCTask / GCTaskQueue are ResourceObjs
141 ResourceMark rm;
142
143 GCTaskQueue* q = GCTaskQueue::create();
144 for (uint i = 0; i < num(); i += 1) {
145 q->enqueue(new ParRestoreGCTask(i, this, total_size_addr));
146 }
147 gc_task_manager->execute_and_wait(q);
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 = NULL;
163 _num = 0;
164 }
165
166 #ifndef PRODUCT
167 void PreservedMarksSet::assert_empty() {
168 assert(_stacks != NULL && _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