1 /* 2 * Copyright (c) 2002, 2016, 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/instanceKlass.inline.hpp" 42 #include "oops/instanceMirrorKlass.inline.hpp" 43 #include "oops/objArrayKlass.inline.hpp" 44 #include "oops/oop.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_develop_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 class ParRestoreGCTask : public GCTask { 244 private: 245 const uint _id; 246 PreservedMarksSet* const _preserved_marks_set; 247 volatile size_t* const _total_size_addr; 248 249 public: 250 virtual char* name() { 251 return (char*) "preserved mark restoration task"; 252 } 253 254 virtual void do_it(GCTaskManager* manager, uint which){ 255 _preserved_marks_set->get(_id)->restore_and_increment(_total_size_addr); 256 } 257 258 ParRestoreGCTask(uint id, 259 PreservedMarksSet* preserved_marks_set, 260 volatile size_t* total_size_addr) 261 : _id(id), 262 _preserved_marks_set(preserved_marks_set), 263 _total_size_addr(total_size_addr) { } 264 }; 265 266 class PSRestorePreservedMarksTaskExecutor : public RestorePreservedMarksTaskExecutor { 267 private: 268 GCTaskManager* _gc_task_manager; 269 270 public: 271 PSRestorePreservedMarksTaskExecutor(GCTaskManager* gc_task_manager) 272 : _gc_task_manager(gc_task_manager) { } 273 274 void restore(PreservedMarksSet* preserved_marks_set, 275 volatile size_t* total_size_addr) { 276 // GCTask / GCTaskQueue are ResourceObjs 277 ResourceMark rm; 278 279 GCTaskQueue* q = GCTaskQueue::create(); 280 for (uint i = 0; i < preserved_marks_set->num(); i += 1) { 281 q->enqueue(new ParRestoreGCTask(i, preserved_marks_set, total_size_addr)); 282 } 283 _gc_task_manager->execute_and_wait(q); 284 } 285 }; 286 287 void PSPromotionManager::restore_preserved_marks() { 288 PSRestorePreservedMarksTaskExecutor task_executor(PSScavenge::gc_task_manager()); 289 _preserved_marks_set->restore(&task_executor); 290 } 291 292 void PSPromotionManager::drain_stacks_depth(bool totally_drain) { 293 totally_drain = totally_drain || _totally_drain; 294 295 #ifdef ASSERT 296 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 297 MutableSpace* to_space = heap->young_gen()->to_space(); 298 MutableSpace* old_space = heap->old_gen()->object_space(); 299 #endif /* ASSERT */ 300 301 OopStarTaskQueue* const tq = claimed_stack_depth(); 302 do { 303 StarTask p; 304 305 // Drain overflow stack first, so other threads can steal from 306 // claimed stack while we work. 307 while (tq->pop_overflow(p)) { 308 process_popped_location_depth(p); 309 } 310 311 if (totally_drain) { 312 while (tq->pop_local(p)) { 313 process_popped_location_depth(p); 314 } 315 } else { 316 while (tq->size() > _target_stack_size && tq->pop_local(p)) { 317 process_popped_location_depth(p); 318 } 319 } 320 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty()); 321 322 assert(!totally_drain || tq->taskqueue_empty(), "Sanity"); 323 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity"); 324 assert(tq->overflow_empty(), "Sanity"); 325 } 326 327 void PSPromotionManager::flush_labs() { 328 assert(stacks_empty(), "Attempt to flush lab with live stack"); 329 330 // If either promotion lab fills up, we can flush the 331 // lab but not refill it, so check first. 332 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity"); 333 if (!_young_lab.is_flushed()) 334 _young_lab.flush(); 335 336 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity"); 337 if (!_old_lab.is_flushed()) 338 _old_lab.flush(); 339 340 // Let PSScavenge know if we overflowed 341 if (_young_gen_is_full) { 342 PSScavenge::set_survivor_overflow(true); 343 } 344 } 345 346 template <class T> void PSPromotionManager::process_array_chunk_work( 347 oop obj, 348 int start, int end) { 349 assert(start <= end, "invariant"); 350 T* const base = (T*)objArrayOop(obj)->base(); 351 T* p = base + start; 352 T* const chunk_end = base + end; 353 while (p < chunk_end) { 354 if (PSScavenge::should_scavenge(p)) { 355 claim_or_forward_depth(p); 356 } 357 ++p; 358 } 359 } 360 361 void PSPromotionManager::process_array_chunk(oop old) { 362 assert(PSChunkLargeArrays, "invariant"); 363 assert(old->is_objArray(), "invariant"); 364 assert(old->is_forwarded(), "invariant"); 365 366 TASKQUEUE_STATS_ONLY(++_array_chunks_processed); 367 368 oop const obj = old->forwardee(); 369 370 int start; 371 int const end = arrayOop(old)->length(); 372 if (end > (int) _min_array_size_for_chunking) { 373 // we'll chunk more 374 start = end - _array_chunk_size; 375 assert(start > 0, "invariant"); 376 arrayOop(old)->set_length(start); 377 push_depth(mask_chunked_array_oop(old)); 378 TASKQUEUE_STATS_ONLY(++_masked_pushes); 379 } else { 380 // this is the final chunk for this array 381 start = 0; 382 int const actual_length = arrayOop(obj)->length(); 383 arrayOop(old)->set_length(actual_length); 384 } 385 386 if (UseCompressedOops) { 387 process_array_chunk_work<narrowOop>(obj, start, end); 388 } else { 389 process_array_chunk_work<oop>(obj, start, end); 390 } 391 } 392 393 class PushContentsClosure : public ExtendedOopClosure { 394 PSPromotionManager* _pm; 395 public: 396 PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {} 397 398 template <typename T> void do_oop_nv(T* p) { 399 if (PSScavenge::should_scavenge(p)) { 400 _pm->claim_or_forward_depth(p); 401 } 402 } 403 404 virtual void do_oop(oop* p) { do_oop_nv(p); } 405 virtual void do_oop(narrowOop* p) { do_oop_nv(p); } 406 407 // Don't use the oop verification code in the oop_oop_iterate framework. 408 debug_only(virtual bool should_verify_oops() { return false; }) 409 }; 410 411 void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 412 PushContentsClosure cl(pm); 413 oop_oop_iterate_oop_maps_reverse<true>(obj, &cl); 414 } 415 416 void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 417 // Note that we don't have to follow the mirror -> klass pointer, since all 418 // klasses that are dirty will be scavenged when we iterate over the 419 // ClassLoaderData objects. 420 421 InstanceKlass::oop_ps_push_contents(obj, pm); 422 423 PushContentsClosure cl(pm); 424 oop_oop_iterate_statics<true>(obj, &cl); 425 } 426 427 void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 428 InstanceKlass::oop_ps_push_contents(obj, pm); 429 430 // This is called by the young collector. It will already have taken care of 431 // all class loader data. So, we don't have to follow the class loader -> 432 // class loader data link. 433 } 434 435 template <class T> 436 static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) { 437 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); 438 if (PSScavenge::should_scavenge(referent_addr)) { 439 ReferenceProcessor* rp = PSScavenge::reference_processor(); 440 if (rp->discover_reference(obj, klass->reference_type())) { 441 // reference already enqueued, referent and next will be traversed later 442 klass->InstanceKlass::oop_ps_push_contents(obj, pm); 443 return; 444 } else { 445 // treat referent as normal oop 446 pm->claim_or_forward_depth(referent_addr); 447 } 448 } 449 // Treat discovered as normal oop, if ref is not "active", 450 // i.e. if next is non-NULL. 451 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); 452 T next_oop = oopDesc::load_heap_oop(next_addr); 453 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active" 454 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); 455 log_develop_trace(gc, ref)(" Process discovered as normal " PTR_FORMAT, p2i(discovered_addr)); 456 if (PSScavenge::should_scavenge(discovered_addr)) { 457 pm->claim_or_forward_depth(discovered_addr); 458 } 459 } 460 // Treat next as normal oop; next is a link in the reference queue. 461 if (PSScavenge::should_scavenge(next_addr)) { 462 pm->claim_or_forward_depth(next_addr); 463 } 464 klass->InstanceKlass::oop_ps_push_contents(obj, pm); 465 } 466 467 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 468 if (UseCompressedOops) { 469 oop_ps_push_contents_specialized<narrowOop>(obj, this, pm); 470 } else { 471 oop_ps_push_contents_specialized<oop>(obj, this, pm); 472 } 473 } 474 475 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 476 assert(obj->is_objArray(), "obj must be obj array"); 477 PushContentsClosure cl(pm); 478 oop_oop_iterate_elements<true>(objArrayOop(obj), &cl); 479 } 480 481 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 482 assert(obj->is_typeArray(),"must be a type array"); 483 ShouldNotReachHere(); 484 } 485 486 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) { 487 assert(_old_gen_is_full || PromotionFailureALot, "Sanity"); 488 489 // Attempt to CAS in the header. 490 // This tests if the header is still the same as when 491 // this started. If it is the same (i.e., no forwarding 492 // pointer has been installed), then this thread owns 493 // it. 494 if (obj->cas_forward_to(obj, obj_mark)) { 495 // We won any races, we "own" this object. 496 assert(obj == obj->forwardee(), "Sanity"); 497 498 _promotion_failed_info.register_copy_failure(obj->size()); 499 500 push_contents(obj); 501 502 _preserved_marks->push_if_necessary(obj, obj_mark); 503 } else { 504 // We lost, someone else "owns" this object 505 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed."); 506 507 // No unallocation to worry about. 508 obj = obj->forwardee(); 509 } 510 511 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size()); 512 513 return obj; 514 }