1 /* 2 * Copyright (c) 2001, 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 #ifndef SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP 26 #define SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP 27 28 #include "gc/shared/gcCause.hpp" 29 #include "gc/shared/gcWhen.hpp" 30 #include "memory/allocation.hpp" 31 #include "runtime/handles.hpp" 32 #include "runtime/perfData.hpp" 33 #include "runtime/safepoint.hpp" 34 #include "utilities/debug.hpp" 35 #include "utilities/events.hpp" 36 #include "utilities/formatBuffer.hpp" 37 #include "utilities/growableArray.hpp" 38 39 // A "CollectedHeap" is an implementation of a java heap for HotSpot. This 40 // is an abstract class: there may be many different kinds of heaps. This 41 // class defines the functions that a heap must implement, and contains 42 // infrastructure common to all heaps. 43 44 class AdaptiveSizePolicy; 45 class BarrierSet; 46 class CollectorPolicy; 47 class GCHeapSummary; 48 class GCTimer; 49 class GCTracer; 50 class GCMemoryManager; 51 class MemoryPool; 52 class MetaspaceSummary; 53 class SoftRefPolicy; 54 class Thread; 55 class ThreadClosure; 56 class VirtualSpaceSummary; 57 class WorkGang; 58 class nmethod; 59 60 class GCMessage : public FormatBuffer<1024> { 61 public: 62 bool is_before; 63 64 public: 65 GCMessage() {} 66 }; 67 68 class CollectedHeap; 69 70 class GCHeapLog : public EventLogBase<GCMessage> { 71 private: 72 void log_heap(CollectedHeap* heap, bool before); 73 74 public: 75 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {} 76 77 void log_heap_before(CollectedHeap* heap) { 78 log_heap(heap, true); 79 } 80 void log_heap_after(CollectedHeap* heap) { 81 log_heap(heap, false); 82 } 83 }; 84 85 // 86 // CollectedHeap 87 // GenCollectedHeap 88 // SerialHeap 89 // CMSHeap 90 // G1CollectedHeap 91 // ParallelScavengeHeap 92 // 93 class CollectedHeap : public CHeapObj<mtInternal> { 94 friend class VMStructs; 95 friend class JVMCIVMStructs; 96 friend class IsGCActiveMark; // Block structured external access to _is_gc_active 97 98 private: 99 #ifdef ASSERT 100 static int _fire_out_of_memory_count; 101 #endif 102 103 GCHeapLog* _gc_heap_log; 104 105 MemRegion _reserved; 106 107 protected: 108 bool _is_gc_active; 109 110 // Used for filler objects (static, but initialized in ctor). 111 static size_t _filler_array_max_size; 112 113 unsigned int _total_collections; // ... started 114 unsigned int _total_full_collections; // ... started 115 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) 116 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) 117 118 // Reason for current garbage collection. Should be set to 119 // a value reflecting no collection between collections. 120 GCCause::Cause _gc_cause; 121 GCCause::Cause _gc_lastcause; 122 PerfStringVariable* _perf_gc_cause; 123 PerfStringVariable* _perf_gc_lastcause; 124 125 // Constructor 126 CollectedHeap(); 127 128 // Create a new tlab. All TLAB allocations must go through this. 129 // To allow more flexible TLAB allocations min_size specifies 130 // the minimum size needed, while requested_size is the requested 131 // size based on ergonomics. The actually allocated size will be 132 // returned in actual_size. 133 virtual HeapWord* allocate_new_tlab(size_t min_size, 134 size_t requested_size, 135 size_t* actual_size); 136 137 // Accumulate statistics on all tlabs. 138 virtual void accumulate_statistics_all_tlabs(); 139 140 // Reinitialize tlabs before resuming mutators. 141 virtual void resize_all_tlabs(); 142 143 // Allocate from the current thread's TLAB, with broken-out slow path. 144 inline static HeapWord* allocate_from_tlab(Klass* klass, size_t size, TRAPS); 145 static HeapWord* allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS); 146 147 inline static HeapWord* allocate_outside_tlab(Klass* klass, size_t size, 148 bool* gc_overhead_limit_was_exceeded, TRAPS); 149 150 // Raw memory allocation facilities 151 // The obj and array allocate methods are covers for these methods. 152 // mem_allocate() should never be 153 // called to allocate TLABs, only individual objects. 154 virtual HeapWord* mem_allocate(size_t size, 155 bool* gc_overhead_limit_was_exceeded) = 0; 156 157 // Allocate an uninitialized block of the given size, or returns NULL if 158 // this is impossible. 159 inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS); 160 161 // Like allocate_init, but the block returned by a successful allocation 162 // is guaranteed initialized to zeros. 163 inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS); 164 165 // Helper functions for (VM) allocation. 166 inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj); 167 inline static void post_allocation_setup_no_klass_install(Klass* klass, 168 HeapWord* objPtr); 169 170 inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size); 171 172 inline static void post_allocation_setup_array(Klass* klass, 173 HeapWord* obj, int length); 174 175 inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size); 176 177 // Clears an allocated object. 178 inline static void init_obj(HeapWord* obj, size_t size); 179 180 // Filler object utilities. 181 static inline size_t filler_array_hdr_size(); 182 static inline size_t filler_array_min_size(); 183 184 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) 185 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) 186 187 // Fill with a single array; caller must ensure filler_array_min_size() <= 188 // words <= filler_array_max_size(). 189 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); 190 191 // Fill with a single object (either an int array or a java.lang.Object). 192 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); 193 194 virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer); 195 196 // Verification functions 197 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) 198 PRODUCT_RETURN; 199 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) 200 PRODUCT_RETURN; 201 debug_only(static void check_for_valid_allocation_state();) 202 203 public: 204 enum Name { 205 None, 206 Serial, 207 Parallel, 208 CMS, 209 G1 210 }; 211 212 static inline size_t filler_array_max_size() { 213 return _filler_array_max_size; 214 } 215 216 virtual Name kind() const = 0; 217 218 virtual const char* name() const = 0; 219 220 /** 221 * Returns JNI error code JNI_ENOMEM if memory could not be allocated, 222 * and JNI_OK on success. 223 */ 224 virtual jint initialize() = 0; 225 226 // In many heaps, there will be a need to perform some initialization activities 227 // after the Universe is fully formed, but before general heap allocation is allowed. 228 // This is the correct place to place such initialization methods. 229 virtual void post_initialize(); 230 231 // Stop any onging concurrent work and prepare for exit. 232 virtual void stop() {} 233 234 // Stop and resume concurrent GC threads interfering with safepoint operations 235 virtual void safepoint_synchronize_begin() {} 236 virtual void safepoint_synchronize_end() {} 237 238 void initialize_reserved_region(HeapWord *start, HeapWord *end); 239 MemRegion reserved_region() const { return _reserved; } 240 address base() const { return (address)reserved_region().start(); } 241 242 virtual size_t capacity() const = 0; 243 virtual size_t used() const = 0; 244 245 // Return "true" if the part of the heap that allocates Java 246 // objects has reached the maximal committed limit that it can 247 // reach, without a garbage collection. 248 virtual bool is_maximal_no_gc() const = 0; 249 250 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of 251 // memory that the vm could make available for storing 'normal' java objects. 252 // This is based on the reserved address space, but should not include space 253 // that the vm uses internally for bookkeeping or temporary storage 254 // (e.g., in the case of the young gen, one of the survivor 255 // spaces). 256 virtual size_t max_capacity() const = 0; 257 258 // Returns "TRUE" if "p" points into the reserved area of the heap. 259 bool is_in_reserved(const void* p) const { 260 return _reserved.contains(p); 261 } 262 263 bool is_in_reserved_or_null(const void* p) const { 264 return p == NULL || is_in_reserved(p); 265 } 266 267 // Returns "TRUE" iff "p" points into the committed areas of the heap. 268 // This method can be expensive so avoid using it in performance critical 269 // code. 270 virtual bool is_in(const void* p) const = 0; 271 272 DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); }) 273 274 // Let's define some terms: a "closed" subset of a heap is one that 275 // 276 // 1) contains all currently-allocated objects, and 277 // 278 // 2) is closed under reference: no object in the closed subset 279 // references one outside the closed subset. 280 // 281 // Membership in a heap's closed subset is useful for assertions. 282 // Clearly, the entire heap is a closed subset, so the default 283 // implementation is to use "is_in_reserved". But this may not be too 284 // liberal to perform useful checking. Also, the "is_in" predicate 285 // defines a closed subset, but may be too expensive, since "is_in" 286 // verifies that its argument points to an object head. The 287 // "closed_subset" method allows a heap to define an intermediate 288 // predicate, allowing more precise checking than "is_in_reserved" at 289 // lower cost than "is_in." 290 291 // One important case is a heap composed of disjoint contiguous spaces, 292 // such as the Garbage-First collector. Such heaps have a convenient 293 // closed subset consisting of the allocated portions of those 294 // contiguous spaces. 295 296 // Return "TRUE" iff the given pointer points into the heap's defined 297 // closed subset (which defaults to the entire heap). 298 virtual bool is_in_closed_subset(const void* p) const { 299 return is_in_reserved(p); 300 } 301 302 bool is_in_closed_subset_or_null(const void* p) const { 303 return p == NULL || is_in_closed_subset(p); 304 } 305 306 void set_gc_cause(GCCause::Cause v) { 307 if (UsePerfData) { 308 _gc_lastcause = _gc_cause; 309 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause)); 310 _perf_gc_cause->set_value(GCCause::to_string(v)); 311 } 312 _gc_cause = v; 313 } 314 GCCause::Cause gc_cause() { return _gc_cause; } 315 316 // General obj/array allocation facilities. 317 inline static oop obj_allocate(Klass* klass, int size, TRAPS); 318 inline static oop array_allocate(Klass* klass, int size, int length, TRAPS); 319 inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS); 320 inline static oop class_allocate(Klass* klass, int size, TRAPS); 321 322 // Raw memory allocation. This may or may not use TLAB allocations to satisfy the 323 // allocation. A GC implementation may override this function to satisfy the allocation 324 // in any way. But the default is to try a TLAB allocation, and otherwise perform 325 // mem_allocate. 326 virtual HeapWord* obj_allocate_raw(Klass* klass, size_t size, 327 bool* gc_overhead_limit_was_exceeded, TRAPS); 328 329 // Utilities for turning raw memory into filler objects. 330 // 331 // min_fill_size() is the smallest region that can be filled. 332 // fill_with_objects() can fill arbitrary-sized regions of the heap using 333 // multiple objects. fill_with_object() is for regions known to be smaller 334 // than the largest array of integers; it uses a single object to fill the 335 // region and has slightly less overhead. 336 static size_t min_fill_size() { 337 return size_t(align_object_size(oopDesc::header_size())); 338 } 339 340 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); 341 342 static void fill_with_object(HeapWord* start, size_t words, bool zap = true); 343 static void fill_with_object(MemRegion region, bool zap = true) { 344 fill_with_object(region.start(), region.word_size(), zap); 345 } 346 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { 347 fill_with_object(start, pointer_delta(end, start), zap); 348 } 349 350 // Return the address "addr" aligned by "alignment_in_bytes" if such 351 // an address is below "end". Return NULL otherwise. 352 inline static HeapWord* align_allocation_or_fail(HeapWord* addr, 353 HeapWord* end, 354 unsigned short alignment_in_bytes); 355 356 // Some heaps may offer a contiguous region for shared non-blocking 357 // allocation, via inlined code (by exporting the address of the top and 358 // end fields defining the extent of the contiguous allocation region.) 359 360 // This function returns "true" iff the heap supports this kind of 361 // allocation. (Default is "no".) 362 virtual bool supports_inline_contig_alloc() const { 363 return false; 364 } 365 // These functions return the addresses of the fields that define the 366 // boundaries of the contiguous allocation area. (These fields should be 367 // physically near to one another.) 368 virtual HeapWord* volatile* top_addr() const { 369 guarantee(false, "inline contiguous allocation not supported"); 370 return NULL; 371 } 372 virtual HeapWord** end_addr() const { 373 guarantee(false, "inline contiguous allocation not supported"); 374 return NULL; 375 } 376 377 // Some heaps may be in an unparseable state at certain times between 378 // collections. This may be necessary for efficient implementation of 379 // certain allocation-related activities. Calling this function before 380 // attempting to parse a heap ensures that the heap is in a parsable 381 // state (provided other concurrent activity does not introduce 382 // unparsability). It is normally expected, therefore, that this 383 // method is invoked with the world stopped. 384 // NOTE: if you override this method, make sure you call 385 // super::ensure_parsability so that the non-generational 386 // part of the work gets done. See implementation of 387 // CollectedHeap::ensure_parsability and, for instance, 388 // that of GenCollectedHeap::ensure_parsability(). 389 // The argument "retire_tlabs" controls whether existing TLABs 390 // are merely filled or also retired, thus preventing further 391 // allocation from them and necessitating allocation of new TLABs. 392 virtual void ensure_parsability(bool retire_tlabs); 393 394 // Section on thread-local allocation buffers (TLABs) 395 // If the heap supports thread-local allocation buffers, it should override 396 // the following methods: 397 // Returns "true" iff the heap supports thread-local allocation buffers. 398 // The default is "no". 399 virtual bool supports_tlab_allocation() const = 0; 400 401 // The amount of space available for thread-local allocation buffers. 402 virtual size_t tlab_capacity(Thread *thr) const = 0; 403 404 // The amount of used space for thread-local allocation buffers for the given thread. 405 virtual size_t tlab_used(Thread *thr) const = 0; 406 407 virtual size_t max_tlab_size() const; 408 409 // An estimate of the maximum allocation that could be performed 410 // for thread-local allocation buffers without triggering any 411 // collection or expansion activity. 412 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { 413 guarantee(false, "thread-local allocation buffers not supported"); 414 return 0; 415 } 416 417 // Perform a collection of the heap; intended for use in implementing 418 // "System.gc". This probably implies as full a collection as the 419 // "CollectedHeap" supports. 420 virtual void collect(GCCause::Cause cause) = 0; 421 422 // Perform a full collection 423 virtual void do_full_collection(bool clear_all_soft_refs) = 0; 424 425 // This interface assumes that it's being called by the 426 // vm thread. It collects the heap assuming that the 427 // heap lock is already held and that we are executing in 428 // the context of the vm thread. 429 virtual void collect_as_vm_thread(GCCause::Cause cause); 430 431 virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 432 size_t size, 433 Metaspace::MetadataType mdtype); 434 435 // Returns "true" iff there is a stop-world GC in progress. (I assume 436 // that it should answer "false" for the concurrent part of a concurrent 437 // collector -- dld). 438 bool is_gc_active() const { return _is_gc_active; } 439 440 // Total number of GC collections (started) 441 unsigned int total_collections() const { return _total_collections; } 442 unsigned int total_full_collections() const { return _total_full_collections;} 443 444 // Increment total number of GC collections (started) 445 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 446 void increment_total_collections(bool full = false) { 447 _total_collections++; 448 if (full) { 449 increment_total_full_collections(); 450 } 451 } 452 453 void increment_total_full_collections() { _total_full_collections++; } 454 455 // Return the CollectorPolicy for the heap 456 virtual CollectorPolicy* collector_policy() const = 0; 457 458 // Return the SoftRefPolicy for the heap; 459 virtual SoftRefPolicy* soft_ref_policy() = 0; 460 461 virtual GrowableArray<GCMemoryManager*> memory_managers() = 0; 462 virtual GrowableArray<MemoryPool*> memory_pools() = 0; 463 464 // Iterate over all objects, calling "cl.do_object" on each. 465 virtual void object_iterate(ObjectClosure* cl) = 0; 466 467 // Similar to object_iterate() except iterates only 468 // over live objects. 469 virtual void safe_object_iterate(ObjectClosure* cl) = 0; 470 471 // NOTE! There is no requirement that a collector implement these 472 // functions. 473 // 474 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 475 // each address in the (reserved) heap is a member of exactly 476 // one block. The defining characteristic of a block is that it is 477 // possible to find its size, and thus to progress forward to the next 478 // block. (Blocks may be of different sizes.) Thus, blocks may 479 // represent Java objects, or they might be free blocks in a 480 // free-list-based heap (or subheap), as long as the two kinds are 481 // distinguishable and the size of each is determinable. 482 483 // Returns the address of the start of the "block" that contains the 484 // address "addr". We say "blocks" instead of "object" since some heaps 485 // may not pack objects densely; a chunk may either be an object or a 486 // non-object. 487 virtual HeapWord* block_start(const void* addr) const = 0; 488 489 // Requires "addr" to be the start of a chunk, and returns its size. 490 // "addr + size" is required to be the start of a new chunk, or the end 491 // of the active area of the heap. 492 virtual size_t block_size(const HeapWord* addr) const = 0; 493 494 // Requires "addr" to be the start of a block, and returns "TRUE" iff 495 // the block is an object. 496 virtual bool block_is_obj(const HeapWord* addr) const = 0; 497 498 // Returns the longest time (in ms) that has elapsed since the last 499 // time that any part of the heap was examined by a garbage collection. 500 virtual jlong millis_since_last_gc() = 0; 501 502 // Perform any cleanup actions necessary before allowing a verification. 503 virtual void prepare_for_verify() = 0; 504 505 // Generate any dumps preceding or following a full gc 506 private: 507 void full_gc_dump(GCTimer* timer, bool before); 508 509 virtual void initialize_serviceability() = 0; 510 511 public: 512 void pre_full_gc_dump(GCTimer* timer); 513 void post_full_gc_dump(GCTimer* timer); 514 515 virtual VirtualSpaceSummary create_heap_space_summary(); 516 GCHeapSummary create_heap_summary(); 517 518 MetaspaceSummary create_metaspace_summary(); 519 520 // Print heap information on the given outputStream. 521 virtual void print_on(outputStream* st) const = 0; 522 // The default behavior is to call print_on() on tty. 523 virtual void print() const { 524 print_on(tty); 525 } 526 // Print more detailed heap information on the given 527 // outputStream. The default behavior is to call print_on(). It is 528 // up to each subclass to override it and add any additional output 529 // it needs. 530 virtual void print_extended_on(outputStream* st) const { 531 print_on(st); 532 } 533 534 virtual void print_on_error(outputStream* st) const; 535 536 // Print all GC threads (other than the VM thread) 537 // used by this heap. 538 virtual void print_gc_threads_on(outputStream* st) const = 0; 539 // The default behavior is to call print_gc_threads_on() on tty. 540 void print_gc_threads() { 541 print_gc_threads_on(tty); 542 } 543 // Iterator for all GC threads (other than VM thread) 544 virtual void gc_threads_do(ThreadClosure* tc) const = 0; 545 546 // Print any relevant tracing info that flags imply. 547 // Default implementation does nothing. 548 virtual void print_tracing_info() const = 0; 549 550 void print_heap_before_gc(); 551 void print_heap_after_gc(); 552 553 // An object is scavengable if its location may move during a scavenge. 554 // (A scavenge is a GC which is not a full GC.) 555 virtual bool is_scavengable(oop obj) = 0; 556 // Registering and unregistering an nmethod (compiled code) with the heap. 557 // Override with specific mechanism for each specialized heap type. 558 virtual void register_nmethod(nmethod* nm) {} 559 virtual void unregister_nmethod(nmethod* nm) {} 560 virtual void verify_nmethod(nmethod* nmethod) {} 561 562 void trace_heap_before_gc(const GCTracer* gc_tracer); 563 void trace_heap_after_gc(const GCTracer* gc_tracer); 564 565 // Heap verification 566 virtual void verify(VerifyOption option) = 0; 567 568 // Return true if concurrent phase control (via 569 // request_concurrent_phase_control) is supported by this collector. 570 // The default implementation returns false. 571 virtual bool supports_concurrent_phase_control() const; 572 573 // Return a NULL terminated array of concurrent phase names provided 574 // by this collector. Supports Whitebox testing. These are the 575 // names recognized by request_concurrent_phase(). The default 576 // implementation returns an array of one NULL element. 577 virtual const char* const* concurrent_phases() const; 578 579 // Request the collector enter the indicated concurrent phase, and 580 // wait until it does so. Supports WhiteBox testing. Only one 581 // request may be active at a time. Phases are designated by name; 582 // the set of names and their meaning is GC-specific. Once the 583 // requested phase has been reached, the collector will attempt to 584 // avoid transitioning to a new phase until a new request is made. 585 // [Note: A collector might not be able to remain in a given phase. 586 // For example, a full collection might cancel an in-progress 587 // concurrent collection.] 588 // 589 // Returns true when the phase is reached. Returns false for an 590 // unknown phase. The default implementation returns false. 591 virtual bool request_concurrent_phase(const char* phase); 592 593 // Provides a thread pool to SafepointSynchronize to use 594 // for parallel safepoint cleanup. 595 // GCs that use a GC worker thread pool may want to share 596 // it for use during safepoint cleanup. This is only possible 597 // if the GC can pause and resume concurrent work (e.g. G1 598 // concurrent marking) for an intermittent non-GC safepoint. 599 // If this method returns NULL, SafepointSynchronize will 600 // perform cleanup tasks serially in the VMThread. 601 virtual WorkGang* get_safepoint_workers() { return NULL; } 602 603 // Support for object pinning. This is used by JNI Get*Critical() 604 // and Release*Critical() family of functions. If supported, the GC 605 // must guarantee that pinned objects never move. 606 virtual bool supports_object_pinning() const; 607 virtual oop pin_object(JavaThread* thread, oop obj); 608 virtual void unpin_object(JavaThread* thread, oop obj); 609 610 // Deduplicate the string, iff the GC supports string deduplication. 611 virtual void deduplicate_string(oop str); 612 613 virtual bool is_oop(oop object) const; 614 615 // Non product verification and debugging. 616 #ifndef PRODUCT 617 // Support for PromotionFailureALot. Return true if it's time to cause a 618 // promotion failure. The no-argument version uses 619 // this->_promotion_failure_alot_count as the counter. 620 bool promotion_should_fail(volatile size_t* count); 621 bool promotion_should_fail(); 622 623 // Reset the PromotionFailureALot counters. Should be called at the end of a 624 // GC in which promotion failure occurred. 625 void reset_promotion_should_fail(volatile size_t* count); 626 void reset_promotion_should_fail(); 627 #endif // #ifndef PRODUCT 628 629 #ifdef ASSERT 630 static int fired_fake_oom() { 631 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); 632 } 633 #endif 634 }; 635 636 // Class to set and reset the GC cause for a CollectedHeap. 637 638 class GCCauseSetter : StackObj { 639 CollectedHeap* _heap; 640 GCCause::Cause _previous_cause; 641 public: 642 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { 643 _heap = heap; 644 _previous_cause = _heap->gc_cause(); 645 _heap->set_gc_cause(cause); 646 } 647 648 ~GCCauseSetter() { 649 _heap->set_gc_cause(_previous_cause); 650 } 651 }; 652 653 #endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP