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