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