1 /* 2 * Copyright (c) 2001, 2017, 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 38 // A "CollectedHeap" is an implementation of a java heap for HotSpot. This 39 // is an abstract class: there may be many different kinds of heaps. This 40 // class defines the functions that a heap must implement, and contains 41 // infrastructure common to all heaps. 42 43 class AdaptiveSizePolicy; 44 class BarrierSet; 45 class CollectorPolicy; 46 class GCHeapSummary; 47 class GCTimer; 48 class GCTracer; 49 class MetaspaceSummary; 50 class Thread; 51 class ThreadClosure; 52 class VirtualSpaceSummary; 53 class nmethod; 54 55 class GCMessage : public FormatBuffer<1024> { 56 public: 57 bool is_before; 58 59 public: 60 GCMessage() {} 61 }; 62 63 class CollectedHeap; 64 65 class GCHeapLog : public EventLogBase<GCMessage> { 66 private: 67 void log_heap(CollectedHeap* heap, bool before); 68 69 public: 70 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {} 71 72 void log_heap_before(CollectedHeap* heap) { 73 log_heap(heap, true); 74 } 75 void log_heap_after(CollectedHeap* heap) { 76 log_heap(heap, false); 77 } 78 }; 79 80 // 81 // CollectedHeap 82 // GenCollectedHeap 83 // G1CollectedHeap 84 // ParallelScavengeHeap 85 // 86 class CollectedHeap : public CHeapObj<mtInternal> { 87 friend class VMStructs; 88 friend class JVMCIVMStructs; 89 friend class IsGCActiveMark; // Block structured external access to _is_gc_active 90 91 private: 92 #ifdef ASSERT 93 static int _fire_out_of_memory_count; 94 #endif 95 96 GCHeapLog* _gc_heap_log; 97 98 // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 99 // or INCLUDE_JVMCI is being used 100 bool _defer_initial_card_mark; 101 102 MemRegion _reserved; 103 104 protected: 105 BarrierSet* _barrier_set; 106 bool _is_gc_active; 107 108 // Used for filler objects (static, but initialized in ctor). 109 static size_t _filler_array_max_size; 110 111 unsigned int _total_collections; // ... started 112 unsigned int _total_full_collections; // ... started 113 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) 114 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) 115 116 // Reason for current garbage collection. Should be set to 117 // a value reflecting no collection between collections. 118 GCCause::Cause _gc_cause; 119 GCCause::Cause _gc_lastcause; 120 PerfStringVariable* _perf_gc_cause; 121 PerfStringVariable* _perf_gc_lastcause; 122 123 // Constructor 124 CollectedHeap(); 125 126 // Do common initializations that must follow instance construction, 127 // for example, those needing virtual calls. 128 // This code could perhaps be moved into initialize() but would 129 // be slightly more awkward because we want the latter to be a 130 // pure virtual. 131 void pre_initialize(); 132 133 // Create a new tlab. All TLAB allocations must go through this. 134 virtual HeapWord* allocate_new_tlab(size_t size); 135 136 // Accumulate statistics on all tlabs. 137 virtual void accumulate_statistics_all_tlabs(); 138 139 // Reinitialize tlabs before resuming mutators. 140 virtual void resize_all_tlabs(); 141 142 // Allocate from the current thread's TLAB, with broken-out slow path. 143 inline static HeapWord* allocate_from_tlab(Klass* klass, Thread* thread, size_t size); 144 static HeapWord* allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size); 145 146 // Allocate an uninitialized block of the given size, or returns NULL if 147 // this is impossible. 148 inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS); 149 150 // Like allocate_init, but the block returned by a successful allocation 151 // is guaranteed initialized to zeros. 152 inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS); 153 154 // Helper functions for (VM) allocation. 155 inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj); 156 inline static void post_allocation_setup_no_klass_install(Klass* klass, 157 HeapWord* objPtr); 158 159 inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size); 160 161 inline static void post_allocation_setup_array(Klass* klass, 162 HeapWord* obj, int length); 163 164 inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size); 165 166 // Clears an allocated object. 167 inline static void init_obj(HeapWord* obj, size_t size); 168 169 // Filler object utilities. 170 static inline size_t filler_array_hdr_size(); 171 static inline size_t filler_array_min_size(); 172 173 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) 174 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) 175 176 // Fill with a single array; caller must ensure filler_array_min_size() <= 177 // words <= filler_array_max_size(). 178 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); 179 180 // Fill with a single object (either an int array or a java.lang.Object). 181 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); 182 183 virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer); 184 185 // Verification functions 186 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) 187 PRODUCT_RETURN; 188 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) 189 PRODUCT_RETURN; 190 debug_only(static void check_for_valid_allocation_state();) 191 192 public: 193 enum Name { 194 GenCollectedHeap, 195 ParallelScavengeHeap, 196 G1CollectedHeap 197 }; 198 199 static inline size_t filler_array_max_size() { 200 return _filler_array_max_size; 201 } 202 203 virtual Name kind() const = 0; 204 205 virtual const char* name() const = 0; 206 207 /** 208 * Returns JNI error code JNI_ENOMEM if memory could not be allocated, 209 * and JNI_OK on success. 210 */ 211 virtual jint initialize() = 0; 212 213 // In many heaps, there will be a need to perform some initialization activities 214 // after the Universe is fully formed, but before general heap allocation is allowed. 215 // This is the correct place to place such initialization methods. 216 virtual void post_initialize() = 0; 217 218 // Stop any onging concurrent work and prepare for exit. 219 virtual void stop() {} 220 221 void initialize_reserved_region(HeapWord *start, HeapWord *end); 222 MemRegion reserved_region() const { return _reserved; } 223 address base() const { return (address)reserved_region().start(); } 224 225 virtual size_t capacity() const = 0; 226 virtual size_t used() const = 0; 227 228 // Return "true" if the part of the heap that allocates Java 229 // objects has reached the maximal committed limit that it can 230 // reach, without a garbage collection. 231 virtual bool is_maximal_no_gc() const = 0; 232 233 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of 234 // memory that the vm could make available for storing 'normal' java objects. 235 // This is based on the reserved address space, but should not include space 236 // that the vm uses internally for bookkeeping or temporary storage 237 // (e.g., in the case of the young gen, one of the survivor 238 // spaces). 239 virtual size_t max_capacity() const = 0; 240 241 // Returns "TRUE" if "p" points into the reserved area of the heap. 242 bool is_in_reserved(const void* p) const { 243 return _reserved.contains(p); 244 } 245 246 bool is_in_reserved_or_null(const void* p) const { 247 return p == NULL || is_in_reserved(p); 248 } 249 250 // Returns "TRUE" iff "p" points into the committed areas of the heap. 251 // This method can be expensive so avoid using it in performance critical 252 // code. 253 virtual bool is_in(const void* p) const = 0; 254 255 DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); }) 256 257 // Let's define some terms: a "closed" subset of a heap is one that 258 // 259 // 1) contains all currently-allocated objects, and 260 // 261 // 2) is closed under reference: no object in the closed subset 262 // references one outside the closed subset. 263 // 264 // Membership in a heap's closed subset is useful for assertions. 265 // Clearly, the entire heap is a closed subset, so the default 266 // implementation is to use "is_in_reserved". But this may not be too 267 // liberal to perform useful checking. Also, the "is_in" predicate 268 // defines a closed subset, but may be too expensive, since "is_in" 269 // verifies that its argument points to an object head. The 270 // "closed_subset" method allows a heap to define an intermediate 271 // predicate, allowing more precise checking than "is_in_reserved" at 272 // lower cost than "is_in." 273 274 // One important case is a heap composed of disjoint contiguous spaces, 275 // such as the Garbage-First collector. Such heaps have a convenient 276 // closed subset consisting of the allocated portions of those 277 // contiguous spaces. 278 279 // Return "TRUE" iff the given pointer points into the heap's defined 280 // closed subset (which defaults to the entire heap). 281 virtual bool is_in_closed_subset(const void* p) const { 282 return is_in_reserved(p); 283 } 284 285 bool is_in_closed_subset_or_null(const void* p) const { 286 return p == NULL || is_in_closed_subset(p); 287 } 288 289 // An object is scavengable if its location may move during a scavenge. 290 // (A scavenge is a GC which is not a full GC.) 291 virtual bool is_scavengable(const void *p) = 0; 292 293 void set_gc_cause(GCCause::Cause v) { 294 if (UsePerfData) { 295 _gc_lastcause = _gc_cause; 296 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause)); 297 _perf_gc_cause->set_value(GCCause::to_string(v)); 298 } 299 _gc_cause = v; 300 } 301 GCCause::Cause gc_cause() { return _gc_cause; } 302 303 // General obj/array allocation facilities. 304 inline static oop obj_allocate(Klass* klass, int size, TRAPS); 305 inline static oop array_allocate(Klass* klass, int size, int length, TRAPS); 306 inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS); 307 inline static oop class_allocate(Klass* klass, int size, TRAPS); 308 309 // Raw memory allocation facilities 310 // The obj and array allocate methods are covers for these methods. 311 // mem_allocate() should never be 312 // called to allocate TLABs, only individual objects. 313 virtual HeapWord* mem_allocate(size_t size, 314 bool* gc_overhead_limit_was_exceeded) = 0; 315 316 // Utilities for turning raw memory into filler objects. 317 // 318 // min_fill_size() is the smallest region that can be filled. 319 // fill_with_objects() can fill arbitrary-sized regions of the heap using 320 // multiple objects. fill_with_object() is for regions known to be smaller 321 // than the largest array of integers; it uses a single object to fill the 322 // region and has slightly less overhead. 323 static size_t min_fill_size() { 324 return size_t(align_object_size(oopDesc::header_size())); 325 } 326 327 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); 328 329 static void fill_with_object(HeapWord* start, size_t words, bool zap = true); 330 static void fill_with_object(MemRegion region, bool zap = true) { 331 fill_with_object(region.start(), region.word_size(), zap); 332 } 333 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { 334 fill_with_object(start, pointer_delta(end, start), zap); 335 } 336 337 // Return the address "addr" aligned by "alignment_in_bytes" if such 338 // an address is below "end". Return NULL otherwise. 339 inline static HeapWord* align_allocation_or_fail(HeapWord* addr, 340 HeapWord* end, 341 unsigned short alignment_in_bytes); 342 343 // Some heaps may offer a contiguous region for shared non-blocking 344 // allocation, via inlined code (by exporting the address of the top and 345 // end fields defining the extent of the contiguous allocation region.) 346 347 // This function returns "true" iff the heap supports this kind of 348 // allocation. (Default is "no".) 349 virtual bool supports_inline_contig_alloc() const { 350 return false; 351 } 352 // These functions return the addresses of the fields that define the 353 // boundaries of the contiguous allocation area. (These fields should be 354 // physically near to one another.) 355 virtual HeapWord* volatile* top_addr() const { 356 guarantee(false, "inline contiguous allocation not supported"); 357 return NULL; 358 } 359 virtual HeapWord** end_addr() const { 360 guarantee(false, "inline contiguous allocation not supported"); 361 return NULL; 362 } 363 364 // Some heaps may be in an unparseable state at certain times between 365 // collections. This may be necessary for efficient implementation of 366 // certain allocation-related activities. Calling this function before 367 // attempting to parse a heap ensures that the heap is in a parsable 368 // state (provided other concurrent activity does not introduce 369 // unparsability). It is normally expected, therefore, that this 370 // method is invoked with the world stopped. 371 // NOTE: if you override this method, make sure you call 372 // super::ensure_parsability so that the non-generational 373 // part of the work gets done. See implementation of 374 // CollectedHeap::ensure_parsability and, for instance, 375 // that of GenCollectedHeap::ensure_parsability(). 376 // The argument "retire_tlabs" controls whether existing TLABs 377 // are merely filled or also retired, thus preventing further 378 // allocation from them and necessitating allocation of new TLABs. 379 virtual void ensure_parsability(bool retire_tlabs); 380 381 // Section on thread-local allocation buffers (TLABs) 382 // If the heap supports thread-local allocation buffers, it should override 383 // the following methods: 384 // Returns "true" iff the heap supports thread-local allocation buffers. 385 // The default is "no". 386 virtual bool supports_tlab_allocation() const = 0; 387 388 // The amount of space available for thread-local allocation buffers. 389 virtual size_t tlab_capacity(Thread *thr) const = 0; 390 391 // The amount of used space for thread-local allocation buffers for the given thread. 392 virtual size_t tlab_used(Thread *thr) const = 0; 393 394 virtual size_t max_tlab_size() const; 395 396 // An estimate of the maximum allocation that could be performed 397 // for thread-local allocation buffers without triggering any 398 // collection or expansion activity. 399 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { 400 guarantee(false, "thread-local allocation buffers not supported"); 401 return 0; 402 } 403 404 // Can a compiler initialize a new object without store barriers? 405 // This permission only extends from the creation of a new object 406 // via a TLAB up to the first subsequent safepoint. If such permission 407 // is granted for this heap type, the compiler promises to call 408 // defer_store_barrier() below on any slow path allocation of 409 // a new object for which such initializing store barriers will 410 // have been elided. 411 virtual bool can_elide_tlab_store_barriers() const = 0; 412 413 // If a compiler is eliding store barriers for TLAB-allocated objects, 414 // there is probably a corresponding slow path which can produce 415 // an object allocated anywhere. The compiler's runtime support 416 // promises to call this function on such a slow-path-allocated 417 // object before performing initializations that have elided 418 // store barriers. Returns new_obj, or maybe a safer copy thereof. 419 virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj); 420 421 // Answers whether an initializing store to a new object currently 422 // allocated at the given address doesn't need a store 423 // barrier. Returns "true" if it doesn't need an initializing 424 // store barrier; answers "false" if it does. 425 virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0; 426 427 // If a compiler is eliding store barriers for TLAB-allocated objects, 428 // we will be informed of a slow-path allocation by a call 429 // to new_store_pre_barrier() above. Such a call precedes the 430 // initialization of the object itself, and no post-store-barriers will 431 // be issued. Some heap types require that the barrier strictly follows 432 // the initializing stores. (This is currently implemented by deferring the 433 // barrier until the next slow-path allocation or gc-related safepoint.) 434 // This interface answers whether a particular heap type needs the card 435 // mark to be thus strictly sequenced after the stores. 436 virtual bool card_mark_must_follow_store() const = 0; 437 438 // If the CollectedHeap was asked to defer a store barrier above, 439 // this informs it to flush such a deferred store barrier to the 440 // remembered set. 441 virtual void flush_deferred_store_barrier(JavaThread* thread); 442 443 // Perform a collection of the heap; intended for use in implementing 444 // "System.gc". This probably implies as full a collection as the 445 // "CollectedHeap" supports. 446 virtual void collect(GCCause::Cause cause) = 0; 447 448 // Perform a full collection 449 virtual void do_full_collection(bool clear_all_soft_refs) = 0; 450 451 // This interface assumes that it's being called by the 452 // vm thread. It collects the heap assuming that the 453 // heap lock is already held and that we are executing in 454 // the context of the vm thread. 455 virtual void collect_as_vm_thread(GCCause::Cause cause); 456 457 // Returns the barrier set for this heap 458 BarrierSet* barrier_set() { return _barrier_set; } 459 void set_barrier_set(BarrierSet* barrier_set); 460 461 // Returns "true" iff there is a stop-world GC in progress. (I assume 462 // that it should answer "false" for the concurrent part of a concurrent 463 // collector -- dld). 464 bool is_gc_active() const { return _is_gc_active; } 465 466 // Total number of GC collections (started) 467 unsigned int total_collections() const { return _total_collections; } 468 unsigned int total_full_collections() const { return _total_full_collections;} 469 470 // Increment total number of GC collections (started) 471 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 472 void increment_total_collections(bool full = false) { 473 _total_collections++; 474 if (full) { 475 increment_total_full_collections(); 476 } 477 } 478 479 void increment_total_full_collections() { _total_full_collections++; } 480 481 // Return the AdaptiveSizePolicy for the heap. 482 virtual AdaptiveSizePolicy* size_policy() = 0; 483 484 // Return the CollectorPolicy for the heap 485 virtual CollectorPolicy* collector_policy() const = 0; 486 487 // Iterate over all objects, calling "cl.do_object" on each. 488 virtual void object_iterate(ObjectClosure* cl) = 0; 489 490 // Similar to object_iterate() except iterates only 491 // over live objects. 492 virtual void safe_object_iterate(ObjectClosure* cl) = 0; 493 494 // NOTE! There is no requirement that a collector implement these 495 // functions. 496 // 497 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 498 // each address in the (reserved) heap is a member of exactly 499 // one block. The defining characteristic of a block is that it is 500 // possible to find its size, and thus to progress forward to the next 501 // block. (Blocks may be of different sizes.) Thus, blocks may 502 // represent Java objects, or they might be free blocks in a 503 // free-list-based heap (or subheap), as long as the two kinds are 504 // distinguishable and the size of each is determinable. 505 506 // Returns the address of the start of the "block" that contains the 507 // address "addr". We say "blocks" instead of "object" since some heaps 508 // may not pack objects densely; a chunk may either be an object or a 509 // non-object. 510 virtual HeapWord* block_start(const void* addr) const = 0; 511 512 // Requires "addr" to be the start of a chunk, and returns its size. 513 // "addr + size" is required to be the start of a new chunk, or the end 514 // of the active area of the heap. 515 virtual size_t block_size(const HeapWord* addr) const = 0; 516 517 // Requires "addr" to be the start of a block, and returns "TRUE" iff 518 // the block is an object. 519 virtual bool block_is_obj(const HeapWord* addr) const = 0; 520 521 // Returns the longest time (in ms) that has elapsed since the last 522 // time that any part of the heap was examined by a garbage collection. 523 virtual jlong millis_since_last_gc() = 0; 524 525 // Perform any cleanup actions necessary before allowing a verification. 526 virtual void prepare_for_verify() = 0; 527 528 // Generate any dumps preceding or following a full gc 529 private: 530 void full_gc_dump(GCTimer* timer, bool before); 531 public: 532 void pre_full_gc_dump(GCTimer* timer); 533 void post_full_gc_dump(GCTimer* timer); 534 535 VirtualSpaceSummary create_heap_space_summary(); 536 GCHeapSummary create_heap_summary(); 537 538 MetaspaceSummary create_metaspace_summary(); 539 540 // Print heap information on the given outputStream. 541 virtual void print_on(outputStream* st) const = 0; 542 // The default behavior is to call print_on() on tty. 543 virtual void print() const { 544 print_on(tty); 545 } 546 // Print more detailed heap information on the given 547 // outputStream. The default behavior is to call print_on(). It is 548 // up to each subclass to override it and add any additional output 549 // it needs. 550 virtual void print_extended_on(outputStream* st) const { 551 print_on(st); 552 } 553 554 virtual void print_on_error(outputStream* st) const; 555 556 // Print all GC threads (other than the VM thread) 557 // used by this heap. 558 virtual void print_gc_threads_on(outputStream* st) const = 0; 559 // The default behavior is to call print_gc_threads_on() on tty. 560 void print_gc_threads() { 561 print_gc_threads_on(tty); 562 } 563 // Iterator for all GC threads (other than VM thread) 564 virtual void gc_threads_do(ThreadClosure* tc) const = 0; 565 566 // Print any relevant tracing info that flags imply. 567 // Default implementation does nothing. 568 virtual void print_tracing_info() const = 0; 569 570 void print_heap_before_gc(); 571 void print_heap_after_gc(); 572 573 // Registering and unregistering an nmethod (compiled code) with the heap. 574 // Override with specific mechanism for each specialized heap type. 575 virtual void register_nmethod(nmethod* nm); 576 virtual void unregister_nmethod(nmethod* nm); 577 578 void trace_heap_before_gc(const GCTracer* gc_tracer); 579 void trace_heap_after_gc(const GCTracer* gc_tracer); 580 581 // Heap verification 582 virtual void verify(VerifyOption option) = 0; 583 584 // Return true if concurrent phase control (via 585 // request_concurrent_phase_control) is supported by this collector. 586 // The default implementation returns false. 587 virtual bool supports_concurrent_phase_control() const; 588 589 // Return a NULL terminated array of concurrent phase names provided 590 // by this collector. Supports Whitebox testing. These are the 591 // names recognized by request_concurrent_phase(). The default 592 // implementation returns an array of one NULL element. 593 virtual const char* const* concurrent_phases() const; 594 595 // Request the collector enter the indicated concurrent phase, and 596 // wait until it does so. Supports WhiteBox testing. Only one 597 // request may be active at a time. Phases are designated by name; 598 // the set of names and their meaning is GC-specific. Once the 599 // requested phase has been reached, the collector will attempt to 600 // avoid transitioning to a new phase until a new request is made. 601 // [Note: A collector might not be able to remain in a given phase. 602 // For example, a full collection might cancel an in-progress 603 // concurrent collection.] 604 // 605 // Returns true when the phase is reached. Returns false for an 606 // unknown phase. The default implementation returns false. 607 virtual bool request_concurrent_phase(const char* phase); 608 609 // Non product verification and debugging. 610 #ifndef PRODUCT 611 // Support for PromotionFailureALot. Return true if it's time to cause a 612 // promotion failure. The no-argument version uses 613 // this->_promotion_failure_alot_count as the counter. 614 inline bool promotion_should_fail(volatile size_t* count); 615 inline bool promotion_should_fail(); 616 617 // Reset the PromotionFailureALot counters. Should be called at the end of a 618 // GC in which promotion failure occurred. 619 inline void reset_promotion_should_fail(volatile size_t* count); 620 inline void reset_promotion_should_fail(); 621 #endif // #ifndef PRODUCT 622 623 #ifdef ASSERT 624 static int fired_fake_oom() { 625 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); 626 } 627 #endif 628 629 public: 630 // Copy the current allocation context statistics for the specified contexts. 631 // For each context in contexts, set the corresponding entries in the totals 632 // and accuracy arrays to the current values held by the statistics. Each 633 // array should be of length len. 634 // Returns true if there are more stats available. 635 virtual bool copy_allocation_context_stats(const jint* contexts, 636 jlong* totals, 637 jbyte* accuracy, 638 jint len) { 639 return false; 640 } 641 642 }; 643 644 // Class to set and reset the GC cause for a CollectedHeap. 645 646 class GCCauseSetter : StackObj { 647 CollectedHeap* _heap; 648 GCCause::Cause _previous_cause; 649 public: 650 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { 651 assert(SafepointSynchronize::is_at_safepoint(), 652 "This method manipulates heap state without locking"); 653 _heap = heap; 654 _previous_cause = _heap->gc_cause(); 655 _heap->set_gc_cause(cause); 656 } 657 658 ~GCCauseSetter() { 659 assert(SafepointSynchronize::is_at_safepoint(), 660 "This method manipulates heap state without locking"); 661 _heap->set_gc_cause(_previous_cause); 662 } 663 }; 664 665 #endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP