1 /*
2 * Copyright (c) 2002, 2018, 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/arrayOop.inline.hpp"
45 #include "oops/compressedOops.inline.hpp"
46 #include "oops/instanceClassLoaderKlass.inline.hpp"
47 #include "oops/instanceKlass.inline.hpp"
48 #include "oops/instanceMirrorKlass.inline.hpp"
49 #include "oops/objArrayKlass.inline.hpp"
50 #include "oops/objArrayOop.inline.hpp"
51 #include "oops/oop.inline.hpp"
52
53 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
54 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
55 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
56 PSOldGen* PSPromotionManager::_old_gen = NULL;
57 MutableSpace* PSPromotionManager::_young_space = NULL;
58
59 void PSPromotionManager::initialize() {
60 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
61
62 _old_gen = heap->old_gen();
63 _young_space = heap->young_gen()->to_space();
64
65 const uint promotion_manager_num = ParallelGCThreads + 1;
66
67 // To prevent false sharing, we pad the PSPromotionManagers
68 // and make sure that the first instance starts at a cache line.
69 assert(_manager_array == NULL, "Attempt to initialize twice");
70 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
71 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
72
73 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
74 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
75
76 // Create and register the PSPromotionManager(s) for the worker threads.
77 for(uint i=0; i<ParallelGCThreads; i++) {
78 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
79 }
80 // The VMThread gets its own PSPromotionManager, which is not available
81 // for work stealing.
82
83 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
84 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
85 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
86 _preserved_marks_set->init(promotion_manager_num);
87 for (uint i = 0; i < promotion_manager_num; i += 1) {
88 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
89 }
90 }
91
92 // Helper functions to get around the circular dependency between
93 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
94 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
95 return PSScavenge::should_scavenge(p, check_to_space);
96 }
97 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
98 return PSScavenge::should_scavenge(p, check_to_space);
99 }
100
101 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
102 assert(index < ParallelGCThreads, "index out of range");
103 assert(_manager_array != NULL, "Sanity");
104 return &_manager_array[index];
105 }
106
107 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
108 assert(_manager_array != NULL, "Sanity");
109 return &_manager_array[ParallelGCThreads];
110 }
111
112 void PSPromotionManager::pre_scavenge() {
113 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
114
115 _preserved_marks_set->assert_empty();
116 _young_space = heap->young_gen()->to_space();
117
118 for(uint i=0; i<ParallelGCThreads+1; i++) {
119 manager_array(i)->reset();
120 }
121 }
122
123 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
124 bool promotion_failure_occurred = false;
125
126 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
127 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
128 PSPromotionManager* manager = manager_array(i);
129 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
130 if (manager->_promotion_failed_info.has_failed()) {
131 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
132 promotion_failure_occurred = true;
133 }
134 manager->flush_labs();
135 }
136 if (!promotion_failure_occurred) {
137 // If there was no promotion failure, the preserved mark stacks
138 // should be empty.
139 _preserved_marks_set->assert_empty();
140 }
141 return promotion_failure_occurred;
142 }
143
144 #if TASKQUEUE_STATS
145 void
146 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
147 #define FMT " " SIZE_FORMAT_W(10)
148 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
149 _arrays_chunked, _array_chunks_processed);
150 #undef FMT
151 }
152
153 static const char* const pm_stats_hdr[] = {
154 " --------masked------- arrays array",
155 "thr push steal chunked chunks",
156 "--- ---------- ---------- ---------- ----------"
157 };
158
159 void
160 PSPromotionManager::print_taskqueue_stats() {
161 if (!log_is_enabled(Trace, gc, task, stats)) {
162 return;
163 }
164 Log(gc, task, stats) log;
165 ResourceMark rm;
166 LogStream ls(log.trace());
167 outputStream* out = &ls;
168 out->print_cr("== GC Tasks Stats, GC %3d",
169 ParallelScavengeHeap::heap()->total_collections());
170
171 TaskQueueStats totals;
172 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
173 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
174 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
175 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
176 out->print("%3d ", i); next.print(out); out->cr();
177 totals += next;
178 }
179 out->print("tot "); totals.print(out); out->cr();
180
181 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
182 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
183 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
184 manager_array(i)->print_local_stats(out, i);
185 }
186 }
187
188 void
189 PSPromotionManager::reset_stats() {
190 claimed_stack_depth()->stats.reset();
191 _masked_pushes = _masked_steals = 0;
192 _arrays_chunked = _array_chunks_processed = 0;
193 }
194 #endif // TASKQUEUE_STATS
195
196 PSPromotionManager::PSPromotionManager() {
197 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
198
199 // We set the old lab's start array.
200 _old_lab.set_start_array(old_gen()->start_array());
201
202 uint queue_size;
203 claimed_stack_depth()->initialize();
204 queue_size = claimed_stack_depth()->max_elems();
205
206 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
207 if (_totally_drain) {
208 _target_stack_size = 0;
209 } else {
210 // don't let the target stack size to be more than 1/4 of the entries
211 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
212 (uint) (queue_size / 4));
213 }
214
215 _array_chunk_size = ParGCArrayScanChunk;
216 // let's choose 1.5x the chunk size
217 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
218
219 _preserved_marks = NULL;
220
221 reset();
222 }
223
224 void PSPromotionManager::reset() {
225 assert(stacks_empty(), "reset of non-empty stack");
226
227 // We need to get an assert in here to make sure the labs are always flushed.
228
229 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
230
231 // Do not prefill the LAB's, save heap wastage!
232 HeapWord* lab_base = young_space()->top();
233 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
234 _young_gen_is_full = false;
235
236 lab_base = old_gen()->object_space()->top();
237 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
238 _old_gen_is_full = false;
239
240 _promotion_failed_info.reset();
241
242 TASKQUEUE_STATS_ONLY(reset_stats());
243 }
244
245 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
246 assert(_preserved_marks == NULL, "do not set it twice");
247 _preserved_marks = preserved_marks;
248 }
249
250 class ParRestoreGCTask : public GCTask {
251 private:
252 const uint _id;
253 PreservedMarksSet* const _preserved_marks_set;
254 volatile size_t* const _total_size_addr;
255
256 public:
257 virtual char* name() {
258 return (char*) "preserved mark restoration task";
259 }
260
261 virtual void do_it(GCTaskManager* manager, uint which){
262 _preserved_marks_set->get(_id)->restore_and_increment(_total_size_addr);
263 }
264
265 ParRestoreGCTask(uint id,
266 PreservedMarksSet* preserved_marks_set,
267 volatile size_t* total_size_addr)
268 : _id(id),
269 _preserved_marks_set(preserved_marks_set),
270 _total_size_addr(total_size_addr) { }
271 };
272
273 class PSRestorePreservedMarksTaskExecutor : public RestorePreservedMarksTaskExecutor {
274 private:
275 GCTaskManager* _gc_task_manager;
276
277 public:
278 PSRestorePreservedMarksTaskExecutor(GCTaskManager* gc_task_manager)
279 : _gc_task_manager(gc_task_manager) { }
280
281 void restore(PreservedMarksSet* preserved_marks_set,
282 volatile size_t* total_size_addr) {
283 // GCTask / GCTaskQueue are ResourceObjs
284 ResourceMark rm;
285
286 GCTaskQueue* q = GCTaskQueue::create();
287 for (uint i = 0; i < preserved_marks_set->num(); i += 1) {
288 q->enqueue(new ParRestoreGCTask(i, preserved_marks_set, total_size_addr));
289 }
290 _gc_task_manager->execute_and_wait(q);
291 }
292 };
293
294 void PSPromotionManager::restore_preserved_marks() {
295 PSRestorePreservedMarksTaskExecutor task_executor(PSScavenge::gc_task_manager());
296 _preserved_marks_set->restore(&task_executor);
297 }
298
299 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
300 totally_drain = totally_drain || _totally_drain;
301
302 #ifdef ASSERT
303 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
304 MutableSpace* to_space = heap->young_gen()->to_space();
305 MutableSpace* old_space = heap->old_gen()->object_space();
306 #endif /* ASSERT */
307
308 OopStarTaskQueue* const tq = claimed_stack_depth();
309 do {
310 StarTask p;
311
312 // Drain overflow stack first, so other threads can steal from
313 // claimed stack while we work.
314 while (tq->pop_overflow(p)) {
315 process_popped_location_depth(p);
316 }
317
318 if (totally_drain) {
319 while (tq->pop_local(p)) {
320 process_popped_location_depth(p);
321 }
322 } else {
323 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
324 process_popped_location_depth(p);
325 }
326 }
327 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
328
329 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
330 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
331 assert(tq->overflow_empty(), "Sanity");
332 }
333
334 void PSPromotionManager::flush_labs() {
335 assert(stacks_empty(), "Attempt to flush lab with live stack");
336
337 // If either promotion lab fills up, we can flush the
338 // lab but not refill it, so check first.
339 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
340 if (!_young_lab.is_flushed())
341 _young_lab.flush();
342
343 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
344 if (!_old_lab.is_flushed())
345 _old_lab.flush();
346
347 // Let PSScavenge know if we overflowed
348 if (_young_gen_is_full) {
349 PSScavenge::set_survivor_overflow(true);
350 }
351 }
352
353 template <class T> void PSPromotionManager::process_array_chunk_work(
354 oop obj,
355 int start, int end) {
356 assert(start <= end, "invariant");
357 T* const base = (T*)objArrayOop(obj)->base();
358 T* p = base + start;
359 T* const chunk_end = base + end;
360 while (p < chunk_end) {
361 if (PSScavenge::should_scavenge(p)) {
362 claim_or_forward_depth(p);
363 }
364 ++p;
365 }
366 }
367
368 void PSPromotionManager::process_array_chunk(oop old) {
369 assert(PSChunkLargeArrays, "invariant");
370 assert(old->is_objArray(), "invariant");
371 assert(old->is_forwarded(), "invariant");
372
373 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
374
375 oop const obj = old->forwardee();
376
377 int start;
378 int const end = arrayOop(old)->length();
379 if (end > (int) _min_array_size_for_chunking) {
380 // we'll chunk more
381 start = end - _array_chunk_size;
382 assert(start > 0, "invariant");
383 arrayOop(old)->set_length(start);
384 push_depth(mask_chunked_array_oop(old));
385 TASKQUEUE_STATS_ONLY(++_masked_pushes);
386 } else {
387 // this is the final chunk for this array
388 start = 0;
389 int const actual_length = arrayOop(obj)->length();
390 arrayOop(old)->set_length(actual_length);
391 }
392
393 if (UseCompressedOops) {
394 process_array_chunk_work<narrowOop>(obj, start, end);
395 } else {
396 process_array_chunk_work<oop>(obj, start, end);
397 }
398 }
399
400 class PushContentsClosure : public BasicOopIterateClosure {
401 PSPromotionManager* _pm;
402 public:
403 PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {}
404
405 template <typename T> void do_oop_work(T* p) {
406 if (PSScavenge::should_scavenge(p)) {
407 _pm->claim_or_forward_depth(p);
408 }
409 }
410
411 virtual void do_oop(oop* p) { do_oop_work(p); }
412 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
413
414 // Don't use the oop verification code in the oop_oop_iterate framework.
415 debug_only(virtual bool should_verify_oops() { return false; })
416 };
417
418 void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
419 PushContentsClosure cl(pm);
420 if (UseCompressedOops) {
421 oop_oop_iterate_oop_maps_reverse<narrowOop>(obj, &cl);
422 } else {
423 oop_oop_iterate_oop_maps_reverse<oop>(obj, &cl);
424 }
425 }
426
427 void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
428 // Note that we don't have to follow the mirror -> klass pointer, since all
429 // klasses that are dirty will be scavenged when we iterate over the
430 // ClassLoaderData objects.
431
432 InstanceKlass::oop_ps_push_contents(obj, pm);
433
434 PushContentsClosure cl(pm);
435 if (UseCompressedOops) {
436 oop_oop_iterate_statics<narrowOop>(obj, &cl);
437 } else {
438 oop_oop_iterate_statics<oop>(obj, &cl);
439 }
440 }
441
442 void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
443 InstanceKlass::oop_ps_push_contents(obj, pm);
444
445 // This is called by the young collector. It will already have taken care of
446 // all class loader data. So, we don't have to follow the class loader ->
447 // class loader data link.
448 }
449
450 template <class T>
451 static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) {
452 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr_raw(obj);
453 if (PSScavenge::should_scavenge(referent_addr)) {
454 ReferenceProcessor* rp = PSScavenge::reference_processor();
455 if (rp->discover_reference(obj, klass->reference_type())) {
456 // reference discovered, referent will be traversed later.
457 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
458 return;
459 } else {
460 // treat referent as normal oop
461 pm->claim_or_forward_depth(referent_addr);
462 }
463 }
464 // Treat discovered as normal oop
465 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr_raw(obj);
466 if (PSScavenge::should_scavenge(discovered_addr)) {
467 pm->claim_or_forward_depth(discovered_addr);
468 }
469 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
470 }
471
472 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
473 if (UseCompressedOops) {
474 oop_ps_push_contents_specialized<narrowOop>(obj, this, pm);
475 } else {
476 oop_ps_push_contents_specialized<oop>(obj, this, pm);
477 }
478 }
479
480 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
481 assert(obj->is_objArray(), "obj must be obj array");
482 PushContentsClosure cl(pm);
483 if (UseCompressedOops) {
484 oop_oop_iterate_elements<narrowOop>(objArrayOop(obj), &cl);
485 } else {
486 oop_oop_iterate_elements<oop>(objArrayOop(obj), &cl);
487 }
488 }
489
490 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
491 assert(obj->is_typeArray(),"must be a type array");
492 ShouldNotReachHere();
493 }
494
495 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
496 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
497
498 // Attempt to CAS in the header.
499 // This tests if the header is still the same as when
500 // this started. If it is the same (i.e., no forwarding
501 // pointer has been installed), then this thread owns
502 // it.
503 if (obj->cas_forward_to(obj, obj_mark)) {
504 // We won any races, we "own" this object.
505 assert(obj == obj->forwardee(), "Sanity");
506
507 _promotion_failed_info.register_copy_failure(obj->size());
508
509 push_contents(obj);
510
511 _preserved_marks->push_if_necessary(obj, obj_mark);
512 } else {
513 // We lost, someone else "owns" this object
514 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
515
516 // No unallocation to worry about.
517 obj = obj->forwardee();
518 }
519
520 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
521
522 return obj;
523 }