1 /* 2 * Copyright (c) 2001, 2019, 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 // WhiteBox API support for concurrent collectors. These are the 166 // default implementations, for collectors which don't support this 167 // feature. 168 bool CollectedHeap::supports_concurrent_phase_control() const { 169 return false; 170 } 171 172 bool CollectedHeap::request_concurrent_phase(const char* phase) { 173 return false; 174 } 175 176 bool CollectedHeap::is_oop(oop object) const { 177 if (!is_object_aligned(object)) { 178 return false; 179 } 180 181 if (!is_in(object)) { 182 return false; 183 } 184 185 if (is_in(object->klass_or_null())) { 186 return false; 187 } 188 189 return true; 190 } 191 192 // Memory state functions. 193 194 195 CollectedHeap::CollectedHeap() : 196 _is_gc_active(false), 197 _total_collections(0), 198 _total_full_collections(0), 199 _gc_cause(GCCause::_no_gc), 200 _gc_lastcause(GCCause::_no_gc) 201 { 202 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT)); 203 const size_t elements_per_word = HeapWordSize / sizeof(jint); 204 _filler_array_max_size = align_object_size(filler_array_hdr_size() + 205 max_len / elements_per_word); 206 207 NOT_PRODUCT(_promotion_failure_alot_count = 0;) 208 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;) 209 210 if (UsePerfData) { 211 EXCEPTION_MARK; 212 213 // create the gc cause jvmstat counters 214 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause", 215 80, GCCause::to_string(_gc_cause), CHECK); 216 217 _perf_gc_lastcause = 218 PerfDataManager::create_string_variable(SUN_GC, "lastCause", 219 80, GCCause::to_string(_gc_lastcause), CHECK); 220 } 221 222 // Create the ring log 223 if (LogEvents) { 224 _gc_heap_log = new GCHeapLog(); 225 } else { 226 _gc_heap_log = NULL; 227 } 228 } 229 230 // This interface assumes that it's being called by the 231 // vm thread. It collects the heap assuming that the 232 // heap lock is already held and that we are executing in 233 // the context of the vm thread. 234 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) { 235 assert(Thread::current()->is_VM_thread(), "Precondition#1"); 236 assert(Heap_lock->is_locked(), "Precondition#2"); 237 GCCauseSetter gcs(this, cause); 238 switch (cause) { 239 case GCCause::_heap_inspection: 240 case GCCause::_heap_dump: 241 case GCCause::_metadata_GC_threshold : { 242 HandleMark hm; 243 do_full_collection(false); // don't clear all soft refs 244 break; 245 } 246 case GCCause::_metadata_GC_clear_soft_refs: { 247 HandleMark hm; 248 do_full_collection(true); // do clear all soft refs 249 break; 250 } 251 default: 252 ShouldNotReachHere(); // Unexpected use of this function 253 } 254 } 255 256 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 257 size_t word_size, 258 Metaspace::MetadataType mdtype) { 259 uint loop_count = 0; 260 uint gc_count = 0; 261 uint full_gc_count = 0; 262 263 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock"); 264 265 do { 266 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype); 267 if (result != NULL) { 268 return result; 269 } 270 271 if (GCLocker::is_active_and_needs_gc()) { 272 // If the GCLocker is active, just expand and allocate. 273 // If that does not succeed, wait if this thread is not 274 // in a critical section itself. 275 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype); 276 if (result != NULL) { 277 return result; 278 } 279 JavaThread* jthr = JavaThread::current(); 280 if (!jthr->in_critical()) { 281 // Wait for JNI critical section to be exited 282 GCLocker::stall_until_clear(); 283 // The GC invoked by the last thread leaving the critical 284 // section will be a young collection and a full collection 285 // is (currently) needed for unloading classes so continue 286 // to the next iteration to get a full GC. 287 continue; 288 } else { 289 if (CheckJNICalls) { 290 fatal("Possible deadlock due to allocating while" 291 " in jni critical section"); 292 } 293 return NULL; 294 } 295 } 296 297 { // Need lock to get self consistent gc_count's 298 MutexLocker ml(Heap_lock); 299 gc_count = Universe::heap()->total_collections(); 300 full_gc_count = Universe::heap()->total_full_collections(); 301 } 302 303 // Generate a VM operation 304 VM_CollectForMetadataAllocation op(loader_data, 305 word_size, 306 mdtype, 307 gc_count, 308 full_gc_count, 309 GCCause::_metadata_GC_threshold); 310 VMThread::execute(&op); 311 312 // If GC was locked out, try again. Check before checking success because the 313 // prologue could have succeeded and the GC still have been locked out. 314 if (op.gc_locked()) { 315 continue; 316 } 317 318 if (op.prologue_succeeded()) { 319 return op.result(); 320 } 321 loop_count++; 322 if ((QueuedAllocationWarningCount > 0) && 323 (loop_count % QueuedAllocationWarningCount == 0)) { 324 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times," 325 " size=" SIZE_FORMAT, loop_count, word_size); 326 } 327 } while (true); // Until a GC is done 328 } 329 330 MemoryUsage CollectedHeap::memory_usage() { 331 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity()); 332 } 333 334 335 #ifndef PRODUCT 336 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) { 337 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 338 // please not mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word 339 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) { 340 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check"); 341 } 342 } 343 } 344 #endif // PRODUCT 345 346 size_t CollectedHeap::max_tlab_size() const { 347 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE]. 348 // This restriction could be removed by enabling filling with multiple arrays. 349 // If we compute that the reasonable way as 350 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize) 351 // we'll overflow on the multiply, so we do the divide first. 352 // We actually lose a little by dividing first, 353 // but that just makes the TLAB somewhat smaller than the biggest array, 354 // which is fine, since we'll be able to fill that. 355 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) + 356 sizeof(jint) * 357 ((juint) max_jint / (size_t) HeapWordSize); 358 return align_down(max_int_size, MinObjAlignment); 359 } 360 361 size_t CollectedHeap::filler_array_hdr_size() { 362 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long 363 } 364 365 size_t CollectedHeap::filler_array_min_size() { 366 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment 367 } 368 369 #ifdef ASSERT 370 void CollectedHeap::fill_args_check(HeapWord* start, size_t words) 371 { 372 assert(words >= min_fill_size(), "too small to fill"); 373 assert(is_object_aligned(words), "unaligned size"); 374 } 375 376 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap) 377 { 378 if (ZapFillerObjects && zap) { 379 Copy::fill_to_words(start + filler_array_hdr_size(), 380 words - filler_array_hdr_size(), 0XDEAFBABE); 381 } 382 } 383 #endif // ASSERT 384 385 void 386 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap) 387 { 388 assert(words >= filler_array_min_size(), "too small for an array"); 389 assert(words <= filler_array_max_size(), "too big for a single object"); 390 391 const size_t payload_size = words - filler_array_hdr_size(); 392 const size_t len = payload_size * HeapWordSize / sizeof(jint); 393 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len); 394 395 ObjArrayAllocator allocator(Universe::intArrayKlassObj(), words, (int)len, /* do_zero */ false); 396 allocator.initialize(start); 397 DEBUG_ONLY(zap_filler_array(start, words, zap);) 398 } 399 400 void 401 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap) 402 { 403 assert(words <= filler_array_max_size(), "too big for a single object"); 404 405 if (words >= filler_array_min_size()) { 406 fill_with_array(start, words, zap); 407 } else if (words > 0) { 408 assert(words == min_fill_size(), "unaligned size"); 409 ObjAllocator allocator(SystemDictionary::Object_klass(), words); 410 allocator.initialize(start); 411 } 412 } 413 414 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap) 415 { 416 DEBUG_ONLY(fill_args_check(start, words);) 417 HandleMark hm; // Free handles before leaving. 418 fill_with_object_impl(start, words, zap); 419 } 420 421 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap) 422 { 423 DEBUG_ONLY(fill_args_check(start, words);) 424 HandleMark hm; // Free handles before leaving. 425 426 // Multiple objects may be required depending on the filler array maximum size. Fill 427 // the range up to that with objects that are filler_array_max_size sized. The 428 // remainder is filled with a single object. 429 const size_t min = min_fill_size(); 430 const size_t max = filler_array_max_size(); 431 while (words > max) { 432 const size_t cur = (words - max) >= min ? max : max - min; 433 fill_with_array(start, cur, zap); 434 start += cur; 435 words -= cur; 436 } 437 438 fill_with_object_impl(start, words, zap); 439 } 440 441 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) { 442 CollectedHeap::fill_with_object(start, end, zap); 443 } 444 445 size_t CollectedHeap::min_dummy_object_size() const { 446 return oopDesc::header_size(); 447 } 448 449 size_t CollectedHeap::tlab_alloc_reserve() const { 450 size_t min_size = min_dummy_object_size(); 451 return min_size > (size_t)MinObjAlignment ? align_object_size(min_size) : 0; 452 } 453 454 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size, 455 size_t requested_size, 456 size_t* actual_size) { 457 guarantee(false, "thread-local allocation buffers not supported"); 458 return NULL; 459 } 460 461 void CollectedHeap::ensure_parsability(bool retire_tlabs) { 462 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(), 463 "Should only be called at a safepoint or at start-up"); 464 465 ThreadLocalAllocStats stats; 466 467 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) { 468 BarrierSet::barrier_set()->make_parsable(thread); 469 if (UseTLAB) { 470 if (retire_tlabs) { 471 thread->tlab().retire(&stats); 472 } else { 473 thread->tlab().make_parsable(); 474 } 475 } 476 } 477 478 stats.publish(); 479 } 480 481 void CollectedHeap::resize_all_tlabs() { 482 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(), 483 "Should only resize tlabs at safepoint"); 484 485 if (UseTLAB && ResizeTLAB) { 486 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { 487 thread->tlab().resize(); 488 } 489 } 490 } 491 492 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) { 493 assert(timer != NULL, "timer is null"); 494 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) { 495 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer); 496 HeapDumper::dump_heap(); 497 } 498 499 LogTarget(Trace, gc, classhisto) lt; 500 if (lt.is_enabled()) { 501 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer); 502 ResourceMark rm; 503 LogStream ls(lt); 504 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */); 505 inspector.doit(); 506 } 507 } 508 509 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) { 510 full_gc_dump(timer, true); 511 } 512 513 void CollectedHeap::post_full_gc_dump(GCTimer* timer) { 514 full_gc_dump(timer, false); 515 } 516 517 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) { 518 // It is important to do this in a way such that concurrent readers can't 519 // temporarily think something is in the heap. (Seen this happen in asserts.) 520 _reserved.set_word_size(0); 521 _reserved.set_start((HeapWord*)rs.base()); 522 _reserved.set_end((HeapWord*)rs.end()); 523 } 524 525 void CollectedHeap::post_initialize() { 526 initialize_serviceability(); 527 } 528 529 #ifndef PRODUCT 530 531 bool CollectedHeap::promotion_should_fail(volatile size_t* count) { 532 // Access to count is not atomic; the value does not have to be exact. 533 if (PromotionFailureALot) { 534 const size_t gc_num = total_collections(); 535 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number; 536 if (elapsed_gcs >= PromotionFailureALotInterval) { 537 // Test for unsigned arithmetic wrap-around. 538 if (++*count >= PromotionFailureALotCount) { 539 *count = 0; 540 return true; 541 } 542 } 543 } 544 return false; 545 } 546 547 bool CollectedHeap::promotion_should_fail() { 548 return promotion_should_fail(&_promotion_failure_alot_count); 549 } 550 551 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) { 552 if (PromotionFailureALot) { 553 _promotion_failure_alot_gc_number = total_collections(); 554 *count = 0; 555 } 556 } 557 558 void CollectedHeap::reset_promotion_should_fail() { 559 reset_promotion_should_fail(&_promotion_failure_alot_count); 560 } 561 562 #endif // #ifndef PRODUCT 563 564 bool CollectedHeap::supports_object_pinning() const { 565 return false; 566 } 567 568 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) { 569 ShouldNotReachHere(); 570 return NULL; 571 } 572 573 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) { 574 ShouldNotReachHere(); 575 } 576 577 void CollectedHeap::deduplicate_string(oop str) { 578 // Do nothing, unless overridden in subclass. 579 } 580 581 size_t CollectedHeap::obj_size(oop obj) const { 582 return obj->size(); 583 } 584 585 uint32_t CollectedHeap::hash_oop(oop obj) const { 586 const uintptr_t addr = cast_from_oop<uintptr_t>(obj); 587 return static_cast<uint32_t>(addr >> LogMinObjAlignment); 588 }