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