1 /*
2 * Copyright (c) 2002, 2020, 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/mutableSpace.hpp"
28 #include "gc/parallel/parallelScavengeHeap.hpp"
29 #include "gc/parallel/psOldGen.hpp"
30 #include "gc/parallel/psPromotionManager.inline.hpp"
31 #include "gc/parallel/psScavenge.inline.hpp"
32 #include "gc/shared/gcTrace.hpp"
33 #include "gc/shared/preservedMarks.inline.hpp"
34 #include "gc/shared/taskqueue.inline.hpp"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "memory/memRegion.hpp"
40 #include "memory/padded.inline.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "oops/access.inline.hpp"
43 #include "oops/compressedOops.inline.hpp"
44
45 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
46 PSPromotionManager::OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
47 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
48 PSOldGen* PSPromotionManager::_old_gen = NULL;
49 MutableSpace* PSPromotionManager::_young_space = NULL;
50
51 void PSPromotionManager::initialize() {
52 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
53
54 _old_gen = heap->old_gen();
55 _young_space = heap->young_gen()->to_space();
56
57 const uint promotion_manager_num = ParallelGCThreads + 1;
58
59 // To prevent false sharing, we pad the PSPromotionManagers
60 // and make sure that the first instance starts at a cache line.
61 assert(_manager_array == NULL, "Attempt to initialize twice");
62 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
63 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
64
65 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
66 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
67
68 // Create and register the PSPromotionManager(s) for the worker threads.
69 for(uint i=0; i<ParallelGCThreads; i++) {
70 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
71 }
72 // The VMThread gets its own PSPromotionManager, which is not available
73 // for work stealing.
74
75 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
76 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
77 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
78 _preserved_marks_set->init(promotion_manager_num);
79 for (uint i = 0; i < promotion_manager_num; i += 1) {
80 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
81 }
82 }
83
84 // Helper functions to get around the circular dependency between
85 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
86 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
87 return PSScavenge::should_scavenge(p, check_to_space);
88 }
89 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
90 return PSScavenge::should_scavenge(p, check_to_space);
91 }
92
93 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
94 assert(index < ParallelGCThreads, "index out of range");
95 assert(_manager_array != NULL, "Sanity");
96 return &_manager_array[index];
97 }
98
99 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
100 assert(_manager_array != NULL, "Sanity");
101 return &_manager_array[ParallelGCThreads];
102 }
103
104 void PSPromotionManager::pre_scavenge() {
105 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
106
107 _preserved_marks_set->assert_empty();
108 _young_space = heap->young_gen()->to_space();
109
110 for(uint i=0; i<ParallelGCThreads+1; i++) {
111 manager_array(i)->reset();
112 }
113 }
114
115 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
116 bool promotion_failure_occurred = false;
117
118 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
119 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
120 PSPromotionManager* manager = manager_array(i);
121 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
122 if (manager->_promotion_failed_info.has_failed()) {
123 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
124 promotion_failure_occurred = true;
125 }
126 manager->flush_labs();
127 }
128 if (!promotion_failure_occurred) {
129 // If there was no promotion failure, the preserved mark stacks
130 // should be empty.
131 _preserved_marks_set->assert_empty();
132 }
133 return promotion_failure_occurred;
134 }
135
136 #if TASKQUEUE_STATS
137 void
138 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
139 #define FMT " " SIZE_FORMAT_W(10)
140 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
141 _arrays_chunked, _array_chunks_processed);
142 #undef FMT
143 }
144
145 static const char* const pm_stats_hdr[] = {
146 " --------masked------- arrays array",
147 "thr push steal chunked chunks",
148 "--- ---------- ---------- ---------- ----------"
149 };
150
151 void
152 PSPromotionManager::print_taskqueue_stats() {
153 if (!log_is_enabled(Trace, gc, task, stats)) {
154 return;
155 }
156 Log(gc, task, stats) log;
157 ResourceMark rm;
158 LogStream ls(log.trace());
159 outputStream* out = &ls;
160 out->print_cr("== GC Tasks Stats, GC %3d",
161 ParallelScavengeHeap::heap()->total_collections());
162
163 TaskQueueStats totals;
164 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
165 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
166 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
167 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
168 out->print("%3d ", i); next.print(out); out->cr();
169 totals += next;
170 }
171 out->print("tot "); totals.print(out); out->cr();
172
173 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
174 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
175 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
176 manager_array(i)->print_local_stats(out, i);
177 }
178 }
179
180 void
181 PSPromotionManager::reset_stats() {
182 claimed_stack_depth()->stats.reset();
183 _masked_pushes = _masked_steals = 0;
184 _arrays_chunked = _array_chunks_processed = 0;
185 }
186 #endif // TASKQUEUE_STATS
187
188 PSPromotionManager::PSPromotionManager() {
189 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
190
191 // We set the old lab's start array.
192 _old_lab.set_start_array(old_gen()->start_array());
193
194 uint queue_size;
195 claimed_stack_depth()->initialize();
196 queue_size = claimed_stack_depth()->max_elems();
197
198 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
199 if (_totally_drain) {
200 _target_stack_size = 0;
201 } else {
202 // don't let the target stack size to be more than 1/4 of the entries
203 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
204 (uint) (queue_size / 4));
205 }
206
207 _array_chunk_size = ParGCArrayScanChunk;
208 // let's choose 1.5x the chunk size
209 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
210
211 _preserved_marks = NULL;
212
213 reset();
214 }
215
216 void PSPromotionManager::reset() {
217 assert(stacks_empty(), "reset of non-empty stack");
218
219 // We need to get an assert in here to make sure the labs are always flushed.
220
221 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
222
223 // Do not prefill the LAB's, save heap wastage!
224 HeapWord* lab_base = young_space()->top();
225 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
226 _young_gen_is_full = false;
227
228 lab_base = old_gen()->object_space()->top();
229 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
230 _old_gen_is_full = false;
231
232 _promotion_failed_info.reset();
233
234 TASKQUEUE_STATS_ONLY(reset_stats());
235 }
236
237 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
238 assert(_preserved_marks == NULL, "do not set it twice");
239 _preserved_marks = preserved_marks;
240 }
241
242 void PSPromotionManager::restore_preserved_marks() {
243 _preserved_marks_set->restore(&ParallelScavengeHeap::heap()->workers());
244 }
245
246 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
247 totally_drain = totally_drain || _totally_drain;
248
249 #ifdef ASSERT
250 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
251 MutableSpace* to_space = heap->young_gen()->to_space();
252 MutableSpace* old_space = heap->old_gen()->object_space();
253 #endif /* ASSERT */
254
255 OopStarTaskQueue* const tq = claimed_stack_depth();
256 do {
257 StarTask p;
258
259 // Drain overflow stack first, so other threads can steal from
260 // claimed stack while we work.
261 while (tq->pop_overflow(p)) {
262 process_popped_location_depth(p);
263 }
264
265 if (totally_drain) {
266 while (tq->pop_local(p)) {
267 process_popped_location_depth(p);
268 }
269 } else {
270 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
271 process_popped_location_depth(p);
272 }
273 }
274 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
275
276 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
277 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
278 assert(tq->overflow_empty(), "Sanity");
279 }
280
281 void PSPromotionManager::flush_labs() {
282 assert(stacks_empty(), "Attempt to flush lab with live stack");
283
284 // If either promotion lab fills up, we can flush the
285 // lab but not refill it, so check first.
286 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
287 if (!_young_lab.is_flushed())
288 _young_lab.flush();
289
290 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
291 if (!_old_lab.is_flushed())
292 _old_lab.flush();
293
294 // Let PSScavenge know if we overflowed
295 if (_young_gen_is_full) {
296 PSScavenge::set_survivor_overflow(true);
297 }
298 }
299
300 template <class T> void PSPromotionManager::process_array_chunk_work(
301 oop obj,
302 int start, int end) {
303 assert(start <= end, "invariant");
304 T* const base = (T*)objArrayOop(obj)->base();
305 T* p = base + start;
306 T* const chunk_end = base + end;
307 while (p < chunk_end) {
308 if (PSScavenge::should_scavenge(p)) {
309 claim_or_forward_depth(p);
310 }
311 ++p;
312 }
313 }
314
315 void PSPromotionManager::process_array_chunk(oop old) {
316 assert(PSChunkLargeArrays, "invariant");
317 assert(old->is_objArray(), "invariant");
318 assert(old->is_forwarded(), "invariant");
319
320 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
321
322 oop const obj = old->forwardee();
323
324 int start;
325 int const end = arrayOop(old)->length();
326 if (end > (int) _min_array_size_for_chunking) {
327 // we'll chunk more
328 start = end - _array_chunk_size;
329 assert(start > 0, "invariant");
330 arrayOop(old)->set_length(start);
331 push_depth(mask_chunked_array_oop(old));
332 TASKQUEUE_STATS_ONLY(++_masked_pushes);
333 } else {
334 // this is the final chunk for this array
335 start = 0;
336 int const actual_length = arrayOop(obj)->length();
337 arrayOop(old)->set_length(actual_length);
338 }
339
340 if (UseCompressedOops) {
341 process_array_chunk_work<narrowOop>(obj, start, end);
342 } else {
343 process_array_chunk_work<oop>(obj, start, end);
344 }
345 }
346
347 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) {
348 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
349
350 // Attempt to CAS in the header.
351 // This tests if the header is still the same as when
352 // this started. If it is the same (i.e., no forwarding
353 // pointer has been installed), then this thread owns
354 // it.
355 if (obj->cas_forward_to(obj, obj_mark)) {
356 // We won any races, we "own" this object.
357 assert(obj == obj->forwardee(), "Sanity");
358
359 _promotion_failed_info.register_copy_failure(obj->size());
360
361 push_contents(obj);
362
363 _preserved_marks->push_if_necessary(obj, obj_mark);
364 } else {
365 // We lost, someone else "owns" this object
366 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
367
368 // No unallocation to worry about.
369 obj = obj->forwardee();
370 }
371
372 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
373
374 return obj;
375 }