1 /* 2 * Copyright (c) 2001, 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/systemDictionary.hpp" 27 #include "gc/shared/allocTracer.hpp" 28 #include "gc/shared/barrierSet.hpp" 29 #include "gc/shared/collectedHeap.hpp" 30 #include "gc/shared/collectedHeap.inline.hpp" 31 #include "gc/shared/gcLocker.inline.hpp" 32 #include "gc/shared/gcHeapSummary.hpp" 33 #include "gc/shared/gcTrace.hpp" 34 #include "gc/shared/gcTraceTime.inline.hpp" 35 #include "gc/shared/gcVMOperations.hpp" 36 #include "gc/shared/gcWhen.hpp" 37 #include "gc/shared/memAllocator.hpp" 38 #include "logging/log.hpp" 39 #include "memory/metaspace.hpp" 40 #include "memory/resourceArea.hpp" 41 #include "memory/universe.hpp" 42 #include "oops/instanceMirrorKlass.hpp" 43 #include "oops/oop.inline.hpp" 44 #include "runtime/handles.inline.hpp" 45 #include "runtime/init.hpp" 46 #include "runtime/thread.inline.hpp" 47 #include "runtime/threadSMR.hpp" 48 #include "runtime/vmThread.hpp" 49 #include "services/heapDumper.hpp" 50 #include "utilities/align.hpp" 51 #include "utilities/copy.hpp" 52 53 class ClassLoaderData; 54 55 size_t CollectedHeap::_filler_array_max_size = 0; 56 57 template <> 58 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) { 59 st->print_cr("GC heap %s", m.is_before ? "before" : "after"); 60 st->print_raw(m); 61 } 62 63 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) { 64 if (!should_log()) { 65 return; 66 } 67 68 double timestamp = fetch_timestamp(); 69 MutexLocker ml(&_mutex, Mutex::_no_safepoint_check_flag); 70 int index = compute_log_index(); 71 _records[index].thread = NULL; // Its the GC thread so it's not that interesting. 72 _records[index].timestamp = timestamp; 73 _records[index].data.is_before = before; 74 stringStream st(_records[index].data.buffer(), _records[index].data.size()); 75 76 st.print_cr("{Heap %s GC invocations=%u (full %u):", 77 before ? "before" : "after", 78 heap->total_collections(), 79 heap->total_full_collections()); 80 81 heap->print_on(&st); 82 st.print_cr("}"); 83 } 84 85 size_t CollectedHeap::unused() const { 86 MutexLocker ml(Heap_lock); 87 return capacity() - used(); 88 } 89 90 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() { 91 size_t capacity_in_words = capacity() / HeapWordSize; 92 93 return VirtualSpaceSummary( 94 _reserved.start(), _reserved.start() + capacity_in_words, _reserved.end()); 95 } 96 97 GCHeapSummary CollectedHeap::create_heap_summary() { 98 VirtualSpaceSummary heap_space = create_heap_space_summary(); 99 return GCHeapSummary(heap_space, used()); 100 } 101 102 MetaspaceSummary CollectedHeap::create_metaspace_summary() { 103 const MetaspaceSizes meta_space( 104 MetaspaceUtils::committed_bytes(), 105 MetaspaceUtils::used_bytes(), 106 MetaspaceUtils::reserved_bytes()); 107 const MetaspaceSizes data_space( 108 MetaspaceUtils::committed_bytes(Metaspace::NonClassType), 109 MetaspaceUtils::used_bytes(Metaspace::NonClassType), 110 MetaspaceUtils::reserved_bytes(Metaspace::NonClassType)); 111 const MetaspaceSizes class_space( 112 MetaspaceUtils::committed_bytes(Metaspace::ClassType), 113 MetaspaceUtils::used_bytes(Metaspace::ClassType), 114 MetaspaceUtils::reserved_bytes(Metaspace::ClassType)); 115 116 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary = 117 MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType); 118 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary = 119 MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType); 120 121 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space, 122 ms_chunk_free_list_summary, class_chunk_free_list_summary); 123 } 124 125 void CollectedHeap::print_heap_before_gc() { 126 Universe::print_heap_before_gc(); 127 if (_gc_heap_log != NULL) { 128 _gc_heap_log->log_heap_before(this); 129 } 130 } 131 132 void CollectedHeap::print_heap_after_gc() { 133 Universe::print_heap_after_gc(); 134 if (_gc_heap_log != NULL) { 135 _gc_heap_log->log_heap_after(this); 136 } 137 } 138 139 void CollectedHeap::print() const { print_on(tty); } 140 141 void CollectedHeap::print_on_error(outputStream* st) const { 142 st->print_cr("Heap:"); 143 print_extended_on(st); 144 st->cr(); 145 146 BarrierSet::barrier_set()->print_on(st); 147 } 148 149 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) { 150 const GCHeapSummary& heap_summary = create_heap_summary(); 151 gc_tracer->report_gc_heap_summary(when, heap_summary); 152 153 const MetaspaceSummary& metaspace_summary = create_metaspace_summary(); 154 gc_tracer->report_metaspace_summary(when, metaspace_summary); 155 } 156 157 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) { 158 trace_heap(GCWhen::BeforeGC, gc_tracer); 159 } 160 161 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) { 162 trace_heap(GCWhen::AfterGC, gc_tracer); 163 } 164 165 // Default implementation, for collectors that don't support the feature. 166 bool CollectedHeap::supports_concurrent_gc_breakpoints() const { 167 return false; 168 } 169 170 bool CollectedHeap::is_oop(oop object) const { 171 if (!is_object_aligned(object)) { 172 return false; 173 } 174 175 if (!is_in(object)) { 176 return false; 177 } 178 179 if (is_in(object->klass_or_null())) { 180 return false; 181 } 182 183 return true; 184 } 185 186 // Memory state functions. 187 188 189 CollectedHeap::CollectedHeap() : 190 _is_gc_active(false), 191 _total_collections(0), 192 _total_full_collections(0), 193 _gc_cause(GCCause::_no_gc), 194 _gc_lastcause(GCCause::_no_gc) 195 { 196 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT)); 197 const size_t elements_per_word = HeapWordSize / sizeof(jint); 198 _filler_array_max_size = align_object_size(filler_array_hdr_size() + 199 max_len / elements_per_word); 200 201 NOT_PRODUCT(_promotion_failure_alot_count = 0;) 202 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;) 203 204 if (UsePerfData) { 205 EXCEPTION_MARK; 206 207 // create the gc cause jvmstat counters 208 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause", 209 80, GCCause::to_string(_gc_cause), CHECK); 210 211 _perf_gc_lastcause = 212 PerfDataManager::create_string_variable(SUN_GC, "lastCause", 213 80, GCCause::to_string(_gc_lastcause), CHECK); 214 } 215 216 // Create the ring log 217 if (LogEvents) { 218 _gc_heap_log = new GCHeapLog(); 219 } else { 220 _gc_heap_log = NULL; 221 } 222 } 223 224 // This interface assumes that it's being called by the 225 // vm thread. It collects the heap assuming that the 226 // heap lock is already held and that we are executing in 227 // the context of the vm thread. 228 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) { 229 assert(Thread::current()->is_VM_thread(), "Precondition#1"); 230 assert(Heap_lock->is_locked(), "Precondition#2"); 231 GCCauseSetter gcs(this, cause); 232 switch (cause) { 233 case GCCause::_heap_inspection: 234 case GCCause::_heap_dump: 235 case GCCause::_metadata_GC_threshold : { 236 HandleMark hm; 237 do_full_collection(false); // don't clear all soft refs 238 break; 239 } 240 case GCCause::_metadata_GC_clear_soft_refs: { 241 HandleMark hm; 242 do_full_collection(true); // do clear all soft refs 243 break; 244 } 245 default: 246 ShouldNotReachHere(); // Unexpected use of this function 247 } 248 } 249 250 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 251 size_t word_size, 252 Metaspace::MetadataType mdtype) { 253 uint loop_count = 0; 254 uint gc_count = 0; 255 uint full_gc_count = 0; 256 257 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock"); 258 259 do { 260 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype); 261 if (result != NULL) { 262 return result; 263 } 264 265 if (GCLocker::is_active_and_needs_gc()) { 266 // If the GCLocker is active, just expand and allocate. 267 // If that does not succeed, wait if this thread is not 268 // in a critical section itself. 269 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype); 270 if (result != NULL) { 271 return result; 272 } 273 JavaThread* jthr = JavaThread::current(); 274 if (!jthr->in_critical()) { 275 // Wait for JNI critical section to be exited 276 GCLocker::stall_until_clear(); 277 // The GC invoked by the last thread leaving the critical 278 // section will be a young collection and a full collection 279 // is (currently) needed for unloading classes so continue 280 // to the next iteration to get a full GC. 281 continue; 282 } else { 283 if (CheckJNICalls) { 284 fatal("Possible deadlock due to allocating while" 285 " in jni critical section"); 286 } 287 return NULL; 288 } 289 } 290 291 { // Need lock to get self consistent gc_count's 292 MutexLocker ml(Heap_lock); 293 gc_count = Universe::heap()->total_collections(); 294 full_gc_count = Universe::heap()->total_full_collections(); 295 } 296 297 // Generate a VM operation 298 VM_CollectForMetadataAllocation op(loader_data, 299 word_size, 300 mdtype, 301 gc_count, 302 full_gc_count, 303 GCCause::_metadata_GC_threshold); 304 VMThread::execute(&op); 305 306 // If GC was locked out, try again. Check before checking success because the 307 // prologue could have succeeded and the GC still have been locked out. 308 if (op.gc_locked()) { 309 continue; 310 } 311 312 if (op.prologue_succeeded()) { 313 return op.result(); 314 } 315 loop_count++; 316 if ((QueuedAllocationWarningCount > 0) && 317 (loop_count % QueuedAllocationWarningCount == 0)) { 318 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times," 319 " size=" SIZE_FORMAT, loop_count, word_size); 320 } 321 } while (true); // Until a GC is done 322 } 323 324 MemoryUsage CollectedHeap::memory_usage() { 325 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity()); 326 } 327 328 329 #ifndef PRODUCT 330 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) { 331 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 332 // please note mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word 333 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) { 334 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check"); 335 } 336 } 337 } 338 #endif // PRODUCT 339 340 size_t CollectedHeap::max_tlab_size() const { 341 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE]. 342 // This restriction could be removed by enabling filling with multiple arrays. 343 // If we compute that the reasonable way as 344 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize) 345 // we'll overflow on the multiply, so we do the divide first. 346 // We actually lose a little by dividing first, 347 // but that just makes the TLAB somewhat smaller than the biggest array, 348 // which is fine, since we'll be able to fill that. 349 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) + 350 sizeof(jint) * 351 ((juint) max_jint / (size_t) HeapWordSize); 352 return align_down(max_int_size, MinObjAlignment); 353 } 354 355 size_t CollectedHeap::filler_array_hdr_size() { 356 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long 357 } 358 359 size_t CollectedHeap::filler_array_min_size() { 360 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment 361 } 362 363 #ifdef ASSERT 364 void CollectedHeap::fill_args_check(HeapWord* start, size_t words) 365 { 366 assert(words >= min_fill_size(), "too small to fill"); 367 assert(is_object_aligned(words), "unaligned size"); 368 } 369 370 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap) 371 { 372 if (ZapFillerObjects && zap) { 373 Copy::fill_to_words(start + filler_array_hdr_size(), 374 words - filler_array_hdr_size(), 0XDEAFBABE); 375 } 376 } 377 #endif // ASSERT 378 379 void 380 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap) 381 { 382 assert(words >= filler_array_min_size(), "too small for an array"); 383 assert(words <= filler_array_max_size(), "too big for a single object"); 384 385 const size_t payload_size = words - filler_array_hdr_size(); 386 const size_t len = payload_size * HeapWordSize / sizeof(jint); 387 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len); 388 389 ObjArrayAllocator allocator(Universe::intArrayKlassObj(), words, (int)len, /* do_zero */ false); 390 allocator.initialize(start); 391 DEBUG_ONLY(zap_filler_array(start, words, zap);) 392 } 393 394 void 395 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap) 396 { 397 assert(words <= filler_array_max_size(), "too big for a single object"); 398 399 if (words >= filler_array_min_size()) { 400 fill_with_array(start, words, zap); 401 } else if (words > 0) { 402 assert(words == min_fill_size(), "unaligned size"); 403 ObjAllocator allocator(SystemDictionary::Object_klass(), words); 404 allocator.initialize(start); 405 } 406 } 407 408 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap) 409 { 410 DEBUG_ONLY(fill_args_check(start, words);) 411 HandleMark hm; // Free handles before leaving. 412 fill_with_object_impl(start, words, zap); 413 } 414 415 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap) 416 { 417 DEBUG_ONLY(fill_args_check(start, words);) 418 HandleMark hm; // Free handles before leaving. 419 420 // Multiple objects may be required depending on the filler array maximum size. Fill 421 // the range up to that with objects that are filler_array_max_size sized. The 422 // remainder is filled with a single object. 423 const size_t min = min_fill_size(); 424 const size_t max = filler_array_max_size(); 425 while (words > max) { 426 const size_t cur = (words - max) >= min ? max : max - min; 427 fill_with_array(start, cur, zap); 428 start += cur; 429 words -= cur; 430 } 431 432 fill_with_object_impl(start, words, zap); 433 } 434 435 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) { 436 CollectedHeap::fill_with_object(start, end, zap); 437 } 438 439 size_t CollectedHeap::min_dummy_object_size() const { 440 return oopDesc::header_size(); 441 } 442 443 size_t CollectedHeap::tlab_alloc_reserve() const { 444 size_t min_size = min_dummy_object_size(); 445 return min_size > (size_t)MinObjAlignment ? align_object_size(min_size) : 0; 446 } 447 448 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size, 449 size_t requested_size, 450 size_t* actual_size) { 451 guarantee(false, "thread-local allocation buffers not supported"); 452 return NULL; 453 } 454 455 void CollectedHeap::ensure_parsability(bool retire_tlabs) { 456 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(), 457 "Should only be called at a safepoint or at start-up"); 458 459 ThreadLocalAllocStats stats; 460 461 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) { 462 BarrierSet::barrier_set()->make_parsable(thread); 463 if (UseTLAB) { 464 if (retire_tlabs) { 465 thread->tlab().retire(&stats); 466 } else { 467 thread->tlab().make_parsable(); 468 } 469 } 470 } 471 472 stats.publish(); 473 } 474 475 void CollectedHeap::resize_all_tlabs() { 476 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(), 477 "Should only resize tlabs at safepoint"); 478 479 if (UseTLAB && ResizeTLAB) { 480 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { 481 thread->tlab().resize(); 482 } 483 } 484 } 485 486 Tickspan CollectedHeap::run_task(AbstractGangTask* task) { 487 Ticks start = Ticks::now(); 488 489 // FIXME 490 Unimplemented(); 491 492 return Ticks::now() - start; 493 } 494 495 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) { 496 assert(timer != NULL, "timer is null"); 497 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) { 498 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer); 499 HeapDumper::dump_heap(); 500 } 501 502 LogTarget(Trace, gc, classhisto) lt; 503 if (lt.is_enabled()) { 504 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer); 505 ResourceMark rm; 506 LogStream ls(lt); 507 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */); 508 inspector.doit(); 509 } 510 } 511 512 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) { 513 full_gc_dump(timer, true); 514 } 515 516 void CollectedHeap::post_full_gc_dump(GCTimer* timer) { 517 full_gc_dump(timer, false); 518 } 519 520 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) { 521 // It is important to do this in a way such that concurrent readers can't 522 // temporarily think something is in the heap. (Seen this happen in asserts.) 523 _reserved.set_word_size(0); 524 _reserved.set_start((HeapWord*)rs.base()); 525 _reserved.set_end((HeapWord*)rs.end()); 526 } 527 528 void CollectedHeap::post_initialize() { 529 initialize_serviceability(); 530 } 531 532 #ifndef PRODUCT 533 534 bool CollectedHeap::promotion_should_fail(volatile size_t* count) { 535 // Access to count is not atomic; the value does not have to be exact. 536 if (PromotionFailureALot) { 537 const size_t gc_num = total_collections(); 538 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number; 539 if (elapsed_gcs >= PromotionFailureALotInterval) { 540 // Test for unsigned arithmetic wrap-around. 541 if (++*count >= PromotionFailureALotCount) { 542 *count = 0; 543 return true; 544 } 545 } 546 } 547 return false; 548 } 549 550 bool CollectedHeap::promotion_should_fail() { 551 return promotion_should_fail(&_promotion_failure_alot_count); 552 } 553 554 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) { 555 if (PromotionFailureALot) { 556 _promotion_failure_alot_gc_number = total_collections(); 557 *count = 0; 558 } 559 } 560 561 void CollectedHeap::reset_promotion_should_fail() { 562 reset_promotion_should_fail(&_promotion_failure_alot_count); 563 } 564 565 #endif // #ifndef PRODUCT 566 567 bool CollectedHeap::supports_object_pinning() const { 568 return false; 569 } 570 571 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) { 572 ShouldNotReachHere(); 573 return NULL; 574 } 575 576 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) { 577 ShouldNotReachHere(); 578 } 579 580 void CollectedHeap::deduplicate_string(oop str) { 581 // Do nothing, unless overridden in subclass. 582 } 583 584 size_t CollectedHeap::obj_size(oop obj) const { 585 return obj->size(); 586 } 587 588 uint32_t CollectedHeap::hash_oop(oop obj) const { 589 const uintptr_t addr = cast_from_oop<uintptr_t>(obj); 590 return static_cast<uint32_t>(addr >> LogMinObjAlignment); 591 }