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