1 /*
2 * Copyright (c) 2002, 2019, 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 "classfile/javaClasses.inline.hpp"
27 #include "gc/parallel/gcTaskManager.hpp"
28 #include "gc/parallel/mutableSpace.hpp"
29 #include "gc/parallel/parallelScavengeHeap.hpp"
30 #include "gc/parallel/psOldGen.hpp"
31 #include "gc/parallel/psPromotionManager.inline.hpp"
32 #include "gc/parallel/psScavenge.inline.hpp"
33 #include "gc/shared/gcTrace.hpp"
34 #include "gc/shared/preservedMarks.inline.hpp"
35 #include "gc/shared/taskqueue.inline.hpp"
36 #include "logging/log.hpp"
37 #include "logging/logStream.hpp"
38 #include "memory/allocation.inline.hpp"
39 #include "memory/iterator.inline.hpp"
40 #include "memory/memRegion.hpp"
41 #include "memory/padded.inline.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "oops/access.inline.hpp"
44 #include "oops/compressedOops.inline.hpp"
45
46 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
47 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
48 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
49 PSOldGen* PSPromotionManager::_old_gen = NULL;
50 MutableSpace* PSPromotionManager::_young_space = NULL;
51
52 void PSPromotionManager::initialize() {
53 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
54
55 _old_gen = heap->old_gen();
56 _young_space = heap->young_gen()->to_space();
57
58 const uint promotion_manager_num = ParallelGCThreads + 1;
59
60 // To prevent false sharing, we pad the PSPromotionManagers
61 // and make sure that the first instance starts at a cache line.
62 assert(_manager_array == NULL, "Attempt to initialize twice");
63 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
64 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
65
66 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
67 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
68
69 // Create and register the PSPromotionManager(s) for the worker threads.
70 for(uint i=0; i<ParallelGCThreads; i++) {
71 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
72 }
73 // The VMThread gets its own PSPromotionManager, which is not available
74 // for work stealing.
75
76 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
77 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
78 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
79 _preserved_marks_set->init(promotion_manager_num);
80 for (uint i = 0; i < promotion_manager_num; i += 1) {
81 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
82 }
83 }
84
85 // Helper functions to get around the circular dependency between
86 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
87 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
88 return PSScavenge::should_scavenge(p, check_to_space);
89 }
90 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
91 return PSScavenge::should_scavenge(p, check_to_space);
92 }
93
94 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
95 assert(index < ParallelGCThreads, "index out of range");
96 assert(_manager_array != NULL, "Sanity");
97 return &_manager_array[index];
98 }
99
100 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
101 assert(_manager_array != NULL, "Sanity");
102 return &_manager_array[ParallelGCThreads];
103 }
104
105 void PSPromotionManager::pre_scavenge() {
106 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
107
108 _preserved_marks_set->assert_empty();
109 _young_space = heap->young_gen()->to_space();
110
111 for(uint i=0; i<ParallelGCThreads+1; i++) {
112 manager_array(i)->reset();
113 }
114 }
115
116 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
117 bool promotion_failure_occurred = false;
118
119 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
120 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
121 PSPromotionManager* manager = manager_array(i);
122 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
123 if (manager->_promotion_failed_info.has_failed()) {
124 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
125 promotion_failure_occurred = true;
126 }
127 manager->flush_labs();
128 }
129 if (!promotion_failure_occurred) {
130 // If there was no promotion failure, the preserved mark stacks
131 // should be empty.
132 _preserved_marks_set->assert_empty();
133 }
134 return promotion_failure_occurred;
135 }
136
137 #if TASKQUEUE_STATS
138 void
139 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
140 #define FMT " " SIZE_FORMAT_W(10)
141 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
142 _arrays_chunked, _array_chunks_processed);
143 #undef FMT
144 }
145
146 static const char* const pm_stats_hdr[] = {
147 " --------masked------- arrays array",
148 "thr push steal chunked chunks",
149 "--- ---------- ---------- ---------- ----------"
150 };
151
152 void
153 PSPromotionManager::print_taskqueue_stats() {
154 if (!log_is_enabled(Trace, gc, task, stats)) {
155 return;
156 }
157 Log(gc, task, stats) log;
158 ResourceMark rm;
159 LogStream ls(log.trace());
160 outputStream* out = &ls;
161 out->print_cr("== GC Tasks Stats, GC %3d",
162 ParallelScavengeHeap::heap()->total_collections());
163
164 TaskQueueStats totals;
165 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
166 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
167 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
168 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
169 out->print("%3d ", i); next.print(out); out->cr();
170 totals += next;
171 }
172 out->print("tot "); totals.print(out); out->cr();
173
174 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
175 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
176 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
177 manager_array(i)->print_local_stats(out, i);
178 }
179 }
180
181 void
182 PSPromotionManager::reset_stats() {
183 claimed_stack_depth()->stats.reset();
184 _masked_pushes = _masked_steals = 0;
185 _arrays_chunked = _array_chunks_processed = 0;
186 }
187 #endif // TASKQUEUE_STATS
188
189 PSPromotionManager::PSPromotionManager() {
190 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
191
192 // We set the old lab's start array.
193 _old_lab.set_start_array(old_gen()->start_array());
194
195 uint queue_size;
196 claimed_stack_depth()->initialize();
197 queue_size = claimed_stack_depth()->max_elems();
198
199 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
200 if (_totally_drain) {
201 _target_stack_size = 0;
202 } else {
203 // don't let the target stack size to be more than 1/4 of the entries
204 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
205 (uint) (queue_size / 4));
206 }
207
208 _array_chunk_size = ParGCArrayScanChunk;
209 // let's choose 1.5x the chunk size
210 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
211
212 _preserved_marks = NULL;
213
214 reset();
215 }
216
217 void PSPromotionManager::reset() {
218 assert(stacks_empty(), "reset of non-empty stack");
219
220 // We need to get an assert in here to make sure the labs are always flushed.
221
222 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
223
224 // Do not prefill the LAB's, save heap wastage!
225 HeapWord* lab_base = young_space()->top();
226 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
227 _young_gen_is_full = false;
228
229 lab_base = old_gen()->object_space()->top();
230 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
231 _old_gen_is_full = false;
232
233 _promotion_failed_info.reset();
234
235 TASKQUEUE_STATS_ONLY(reset_stats());
236 }
237
238 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
239 assert(_preserved_marks == NULL, "do not set it twice");
240 _preserved_marks = preserved_marks;
241 }
242
243 void PSPromotionManager::restore_preserved_marks() {
244 SharedRestorePreservedMarksTaskExecutor task_executor(&ParallelScavengeHeap::heap()->workers());
245 _preserved_marks_set->restore(&task_executor);
246 }
247
248 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
249 totally_drain = totally_drain || _totally_drain;
250
251 #ifdef ASSERT
252 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
253 MutableSpace* to_space = heap->young_gen()->to_space();
254 MutableSpace* old_space = heap->old_gen()->object_space();
255 #endif /* ASSERT */
256
257 OopStarTaskQueue* const tq = claimed_stack_depth();
258 do {
259 StarTask p;
260
261 // Drain overflow stack first, so other threads can steal from
262 // claimed stack while we work.
263 while (tq->pop_overflow(p)) {
264 process_popped_location_depth(p);
265 }
266
267 if (totally_drain) {
268 while (tq->pop_local(p)) {
269 process_popped_location_depth(p);
270 }
271 } else {
272 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
273 process_popped_location_depth(p);
274 }
275 }
276 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
277
278 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
279 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
280 assert(tq->overflow_empty(), "Sanity");
281 }
282
283 void PSPromotionManager::flush_labs() {
284 assert(stacks_empty(), "Attempt to flush lab with live stack");
285
286 // If either promotion lab fills up, we can flush the
287 // lab but not refill it, so check first.
288 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
289 if (!_young_lab.is_flushed())
290 _young_lab.flush();
291
292 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
293 if (!_old_lab.is_flushed())
294 _old_lab.flush();
295
296 // Let PSScavenge know if we overflowed
297 if (_young_gen_is_full) {
298 PSScavenge::set_survivor_overflow(true);
299 }
300 }
301
302 template <class T> void PSPromotionManager::process_array_chunk_work(
303 oop obj,
304 int start, int end) {
305 assert(start <= end, "invariant");
306 T* const base = (T*)objArrayOop(obj)->base();
307 T* p = base + start;
308 T* const chunk_end = base + end;
309 while (p < chunk_end) {
310 if (PSScavenge::should_scavenge(p)) {
311 claim_or_forward_depth(p);
312 }
313 ++p;
314 }
315 }
316
317 void PSPromotionManager::process_array_chunk(oop old) {
318 assert(PSChunkLargeArrays, "invariant");
319 assert(old->is_objArray(), "invariant");
320 assert(old->is_forwarded(), "invariant");
321
322 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
323
324 oop const obj = old->forwardee();
325
326 int start;
327 int const end = arrayOop(old)->length();
328 if (end > (int) _min_array_size_for_chunking) {
329 // we'll chunk more
330 start = end - _array_chunk_size;
331 assert(start > 0, "invariant");
332 arrayOop(old)->set_length(start);
333 push_depth(mask_chunked_array_oop(old));
334 TASKQUEUE_STATS_ONLY(++_masked_pushes);
335 } else {
336 // this is the final chunk for this array
337 start = 0;
338 int const actual_length = arrayOop(obj)->length();
339 arrayOop(old)->set_length(actual_length);
340 }
341
342 if (UseCompressedOops) {
343 process_array_chunk_work<narrowOop>(obj, start, end);
344 } else {
345 process_array_chunk_work<oop>(obj, start, end);
346 }
347 }
348
349 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
350 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
351
352 // Attempt to CAS in the header.
353 // This tests if the header is still the same as when
354 // this started. If it is the same (i.e., no forwarding
355 // pointer has been installed), then this thread owns
356 // it.
357 if (obj->cas_forward_to(obj, obj_mark)) {
358 // We won any races, we "own" this object.
359 assert(obj == obj->forwardee(), "Sanity");
360
361 _promotion_failed_info.register_copy_failure(obj->size());
362
363 push_contents(obj);
364
365 _preserved_marks->push_if_necessary(obj, obj_mark);
366 } else {
367 // We lost, someone else "owns" this object
368 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
369
370 // No unallocation to worry about.
371 obj = obj->forwardee();
372 }
373
374 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
375
376 return obj;
377 }