1 /*
2 * Copyright (c) 2005, 2025, 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 "gc/parallel/objectStartArray.hpp"
26 #include "gc/parallel/parallelScavengeHeap.hpp"
27 #include "gc/parallel/parMarkBitMap.inline.hpp"
28 #include "gc/parallel/psCompactionManager.inline.hpp"
29 #include "gc/parallel/psOldGen.hpp"
30 #include "gc/parallel/psParallelCompact.inline.hpp"
31 #include "gc/shared/partialArraySplitter.inline.hpp"
32 #include "gc/shared/partialArrayState.hpp"
33 #include "gc/shared/preservedMarks.inline.hpp"
34 #include "gc/shared/taskqueue.inline.hpp"
35 #include "logging/log.hpp"
36 #include "memory/iterator.inline.hpp"
37 #include "oops/access.inline.hpp"
38 #include "oops/compressedOops.inline.hpp"
39 #include "oops/instanceKlass.inline.hpp"
40 #include "oops/instanceMirrorKlass.inline.hpp"
41 #include "oops/objArrayKlass.inline.hpp"
42 #include "oops/oop.inline.hpp"
43
44 PSOldGen* ParCompactionManager::_old_gen = nullptr;
45 ParCompactionManager** ParCompactionManager::_manager_array = nullptr;
46
47 ParCompactionManager::PSMarkTasksQueueSet* ParCompactionManager::_marking_stacks = nullptr;
48 ParCompactionManager::RegionTaskQueueSet* ParCompactionManager::_region_task_queues = nullptr;
49 PartialArrayStateManager* ParCompactionManager::_partial_array_state_manager = nullptr;
50
51 ObjectStartArray* ParCompactionManager::_start_array = nullptr;
52 ParMarkBitMap* ParCompactionManager::_mark_bitmap = nullptr;
53 GrowableArray<size_t >* ParCompactionManager::_shadow_region_array = nullptr;
54 Monitor* ParCompactionManager::_shadow_region_monitor = nullptr;
55
56 PreservedMarksSet* ParCompactionManager::_preserved_marks_set = nullptr;
57
58 ParCompactionManager::ParCompactionManager(PreservedMarks* preserved_marks,
59 ReferenceProcessor* ref_processor,
60 uint parallel_gc_threads)
61 :_partial_array_splitter(_partial_array_state_manager, parallel_gc_threads),
62 _mark_and_push_closure(this, ref_processor) {
63
64 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
65
66 _old_gen = heap->old_gen();
67 _start_array = old_gen()->start_array();
68
69 _preserved_marks = preserved_marks;
70 _marking_stats_cache = nullptr;
71 }
72
73 void ParCompactionManager::initialize(ParMarkBitMap* mbm) {
74 assert(ParallelScavengeHeap::heap() != nullptr, "Needed for initialization");
75 assert(PSParallelCompact::ref_processor() != nullptr, "precondition");
76 assert(ParallelScavengeHeap::heap()->workers().max_workers() != 0, "Not initialized?");
77
78 _mark_bitmap = mbm;
79
80 uint parallel_gc_threads = ParallelScavengeHeap::heap()->workers().max_workers();
81
82 assert(_manager_array == nullptr, "Attempt to initialize twice");
83 _manager_array = NEW_C_HEAP_ARRAY(ParCompactionManager*, parallel_gc_threads, mtGC);
84
85 assert(_partial_array_state_manager == nullptr, "Attempt to initialize twice");
86 _partial_array_state_manager
87 = new PartialArrayStateManager(parallel_gc_threads);
88 _marking_stacks = new PSMarkTasksQueueSet(parallel_gc_threads);
89 _region_task_queues = new RegionTaskQueueSet(parallel_gc_threads);
90
91 _preserved_marks_set = new PreservedMarksSet(true);
92 _preserved_marks_set->init(parallel_gc_threads);
93
94 // Create and register the ParCompactionManager(s) for the worker threads.
95 for(uint i=0; i<parallel_gc_threads; i++) {
96 _manager_array[i] = new ParCompactionManager(_preserved_marks_set->get(i),
97 PSParallelCompact::ref_processor(),
98 parallel_gc_threads);
99 marking_stacks()->register_queue(i, _manager_array[i]->marking_stack());
100 region_task_queues()->register_queue(i, _manager_array[i]->region_stack());
101 }
102
103 _shadow_region_array = new (mtGC) GrowableArray<size_t >(10, mtGC);
104
105 _shadow_region_monitor = new Monitor(Mutex::nosafepoint, "CompactionManager_lock");
106 }
107
108 void ParCompactionManager::flush_all_string_dedup_requests() {
109 uint parallel_gc_threads = ParallelScavengeHeap::heap()->workers().max_workers();
110 for (uint i=0; i<parallel_gc_threads; i++) {
111 _manager_array[i]->flush_string_dedup_requests();
112 }
113 }
114
115 ParCompactionManager*
116 ParCompactionManager::gc_thread_compaction_manager(uint index) {
117 assert(index < ParallelGCThreads, "index out of range");
118 assert(_manager_array != nullptr, "Sanity");
119 return _manager_array[index];
120 }
121
122 void ParCompactionManager::push_objArray(oop obj) {
123 assert(obj->is_objArray(), "precondition");
124 _mark_and_push_closure.do_klass(obj->klass());
125
126 objArrayOop obj_array = objArrayOop(obj);
127 size_t array_length = obj_array->length();
128 size_t initial_chunk_size =
129 _partial_array_splitter.start(&_marking_stack, obj_array, nullptr, array_length);
130 follow_array(obj_array, 0, initial_chunk_size);
131 }
132
133 void ParCompactionManager::process_array_chunk(PartialArrayState* state, bool stolen) {
134 // Access before release by claim().
135 oop obj = state->source();
136 PartialArraySplitter::Claim claim =
137 _partial_array_splitter.claim(state, &_marking_stack, stolen);
138 follow_array(objArrayOop(obj), claim._start, claim._end);
139 }
140
141 void ParCompactionManager::follow_marking_stacks() {
142 ScannerTask task;
143 do {
144 // First, try to move tasks from the overflow stack into the shared buffer, so
145 // that other threads can steal. Otherwise process the overflow stack first.
146 while (marking_stack()->pop_overflow(task)) {
147 if (!marking_stack()->try_push_to_taskqueue(task)) {
148 follow_contents(task, false);
149 }
150 }
151 while (marking_stack()->pop_local(task)) {
152 follow_contents(task, false);
153 }
154 } while (!marking_stack_empty());
155
156 assert(marking_stack_empty(), "Sanity");
157 }
158
159 void ParCompactionManager::drain_region_stacks() {
160 do {
161 // Drain overflow stack first so other threads can steal.
162 size_t region_index;
163 while (region_stack()->pop_overflow(region_index)) {
164 PSParallelCompact::fill_and_update_region(this, region_index);
165 }
166
167 while (region_stack()->pop_local(region_index)) {
168 PSParallelCompact::fill_and_update_region(this, region_index);
169 }
170 } while (!region_stack()->is_empty());
171 }
172
173 size_t ParCompactionManager::pop_shadow_region_mt_safe(PSParallelCompact::RegionData* region_ptr) {
174 MonitorLocker ml(_shadow_region_monitor, Mutex::_no_safepoint_check_flag);
175 while (true) {
176 if (!_shadow_region_array->is_empty()) {
177 return _shadow_region_array->pop();
178 }
179 // Check if the corresponding heap region is available now.
180 // If so, we don't need to get a shadow region anymore, and
181 // we return InvalidShadow to indicate such a case.
182 if (region_ptr->claimed()) {
183 return InvalidShadow;
184 }
185 ml.wait(1);
186 }
187 }
188
189 void ParCompactionManager::push_shadow_region_mt_safe(size_t shadow_region) {
190 MonitorLocker ml(_shadow_region_monitor, Mutex::_no_safepoint_check_flag);
191 _shadow_region_array->push(shadow_region);
192 ml.notify();
193 }
194
195 void ParCompactionManager::push_shadow_region(size_t shadow_region) {
196 _shadow_region_array->push(shadow_region);
197 }
198
199 void ParCompactionManager::remove_all_shadow_regions() {
200 _shadow_region_array->clear();
201 }
202
203
204 #if TASKQUEUE_STATS
205 void ParCompactionManager::print_and_reset_taskqueue_stats() {
206 marking_stacks()->print_and_reset_taskqueue_stats("Marking Stacks");
207
208 auto get_pa_stats = [&](uint i) {
209 return _manager_array[i]->partial_array_task_stats();
210 };
211 PartialArrayTaskStats::log_set(ParallelGCThreads, get_pa_stats,
212 "Partial Array Task Stats");
213 uint parallel_gc_threads = ParallelScavengeHeap::heap()->workers().max_workers();
214 for (uint i = 0; i < parallel_gc_threads; ++i) {
215 get_pa_stats(i)->reset();
216 }
217 }
218
219 PartialArrayTaskStats* ParCompactionManager::partial_array_task_stats() {
220 return _partial_array_splitter.stats();
221 }
222 #endif // TASKQUEUE_STATS
223
224 #ifdef ASSERT
225 void ParCompactionManager::verify_all_marking_stack_empty() {
226 uint parallel_gc_threads = ParallelGCThreads;
227 for (uint i = 0; i < parallel_gc_threads; i++) {
228 assert(_manager_array[i]->marking_stack_empty(), "Marking stack should be empty");
229 }
230 }
231
232 void ParCompactionManager::verify_all_region_stack_empty() {
233 uint parallel_gc_threads = ParallelGCThreads;
234 for (uint i = 0; i < parallel_gc_threads; i++) {
235 assert(_manager_array[i]->region_stack()->is_empty(), "Region stack should be empty");
236 }
237 }
238 #endif