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 // CMSHeap 86 // 87 class CollectedHeap : public CHeapObj<mtInternal> { 88 friend class VMStructs; 89 friend class JVMCIVMStructs; 90 friend class IsGCActiveMark; // Block structured external access to _is_gc_active 91 92 private: 93 #ifdef ASSERT 94 static int _fire_out_of_memory_count; 95 #endif 96 97 GCHeapLog* _gc_heap_log; 98 99 // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 100 // or INCLUDE_JVMCI is being used 101 bool _defer_initial_card_mark; 102 103 MemRegion _reserved; 104 105 protected: 106 BarrierSet* _barrier_set; 107 bool _is_gc_active; 108 109 // Used for filler objects (static, but initialized in ctor). 110 static size_t _filler_array_max_size; 111 112 unsigned int _total_collections; // ... started 113 unsigned int _total_full_collections; // ... started 114 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) 115 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) 116 117 // Reason for current garbage collection. Should be set to 118 // a value reflecting no collection between collections. 119 GCCause::Cause _gc_cause; 120 GCCause::Cause _gc_lastcause; 121 PerfStringVariable* _perf_gc_cause; 122 PerfStringVariable* _perf_gc_lastcause; 123 124 // Constructor 125 CollectedHeap(); 126 127 // Do common initializations that must follow instance construction, 128 // for example, those needing virtual calls. 129 // This code could perhaps be moved into initialize() but would 130 // be slightly more awkward because we want the latter to be a 131 // pure virtual. 132 void pre_initialize(); 133 134 // Create a new tlab. All TLAB allocations must go through this. 135 virtual HeapWord* allocate_new_tlab(size_t 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, Thread* thread, size_t size); 145 static HeapWord* allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size); 146 147 // Allocate an uninitialized block of the given size, or returns NULL if 148 // this is impossible. 149 inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS); 150 151 // Like allocate_init, but the block returned by a successful allocation 152 // is guaranteed initialized to zeros. 153 inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS); 154 155 // Helper functions for (VM) allocation. 156 inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj); 157 inline static void post_allocation_setup_no_klass_install(Klass* klass, 158 HeapWord* objPtr); 159 160 inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size); 161 162 inline static void post_allocation_setup_array(Klass* klass, 163 HeapWord* obj, int length); 164 165 inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size); 166 167 // Clears an allocated object. 168 inline static void init_obj(HeapWord* obj, size_t size); 169 170 // Filler object utilities. 171 static inline size_t filler_array_hdr_size(); 172 static inline size_t filler_array_min_size(); 173 174 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) 175 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) 176 177 // Fill with a single array; caller must ensure filler_array_min_size() <= 178 // words <= filler_array_max_size(). 179 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); 180 181 // Fill with a single object (either an int array or a java.lang.Object). 182 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); 183 184 virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer); 185 186 // Verification functions 187 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) 188 PRODUCT_RETURN; 189 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) 190 PRODUCT_RETURN; 191 debug_only(static void check_for_valid_allocation_state();) 192 193 public: 194 enum Name { 195 GenCollectedHeap, 196 ParallelScavengeHeap, 197 G1CollectedHeap, 198 CMSHeap 199 }; 200 201 static inline size_t filler_array_max_size() { 202 return _filler_array_max_size; 203 } 204 205 virtual Name kind() const = 0; 206 207 virtual const char* name() const = 0; 208 209 /** 210 * Returns JNI error code JNI_ENOMEM if memory could not be allocated, 211 * and JNI_OK on success. 212 */ 213 virtual jint initialize() = 0; 214 215 // In many heaps, there will be a need to perform some initialization activities 216 // after the Universe is fully formed, but before general heap allocation is allowed. 217 // This is the correct place to place such initialization methods. 218 virtual void post_initialize() = 0; 219 220 // Stop any onging concurrent work and prepare for exit. 221 virtual void stop() {} 222 223 void initialize_reserved_region(HeapWord *start, HeapWord *end); 224 MemRegion reserved_region() const { return _reserved; } 225 address base() const { return (address)reserved_region().start(); } 226 227 virtual size_t capacity() const = 0; 228 virtual size_t used() const = 0; 229 230 // Return "true" if the part of the heap that allocates Java 231 // objects has reached the maximal committed limit that it can 232 // reach, without a garbage collection. 233 virtual bool is_maximal_no_gc() const = 0; 234 235 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of 236 // memory that the vm could make available for storing 'normal' java objects. 237 // This is based on the reserved address space, but should not include space 238 // that the vm uses internally for bookkeeping or temporary storage 239 // (e.g., in the case of the young gen, one of the survivor 240 // spaces). 241 virtual size_t max_capacity() const = 0; 242 243 // Returns "TRUE" if "p" points into the reserved area of the heap. 244 bool is_in_reserved(const void* p) const { 245 return _reserved.contains(p); 246 } 247 248 bool is_in_reserved_or_null(const void* p) const { 249 return p == NULL || is_in_reserved(p); 250 } 251 252 // Returns "TRUE" iff "p" points into the committed areas of the heap. 253 // This method can be expensive so avoid using it in performance critical 254 // code. 255 virtual bool is_in(const void* p) const = 0; 256 257 DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); }) 258 259 // Let's define some terms: a "closed" subset of a heap is one that 260 // 261 // 1) contains all currently-allocated objects, and 262 // 263 // 2) is closed under reference: no object in the closed subset 264 // references one outside the closed subset. 265 // 266 // Membership in a heap's closed subset is useful for assertions. 267 // Clearly, the entire heap is a closed subset, so the default 268 // implementation is to use "is_in_reserved". But this may not be too 269 // liberal to perform useful checking. Also, the "is_in" predicate 270 // defines a closed subset, but may be too expensive, since "is_in" 271 // verifies that its argument points to an object head. The 272 // "closed_subset" method allows a heap to define an intermediate 273 // predicate, allowing more precise checking than "is_in_reserved" at 274 // lower cost than "is_in." 275 276 // One important case is a heap composed of disjoint contiguous spaces, 277 // such as the Garbage-First collector. Such heaps have a convenient 278 // closed subset consisting of the allocated portions of those 279 // contiguous spaces. 280 281 // Return "TRUE" iff the given pointer points into the heap's defined 282 // closed subset (which defaults to the entire heap). 283 virtual bool is_in_closed_subset(const void* p) const { 284 return is_in_reserved(p); 285 } 286 287 bool is_in_closed_subset_or_null(const void* p) const { 288 return p == NULL || is_in_closed_subset(p); 289 } 290 291 // An object is scavengable if its location may move during a scavenge. 292 // (A scavenge is a GC which is not a full GC.) 293 virtual bool is_scavengable(const void *p) = 0; 294 295 void set_gc_cause(GCCause::Cause v) { 296 if (UsePerfData) { 297 _gc_lastcause = _gc_cause; 298 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause)); 299 _perf_gc_cause->set_value(GCCause::to_string(v)); 300 } 301 _gc_cause = v; 302 } 303 GCCause::Cause gc_cause() { return _gc_cause; } 304 305 // General obj/array allocation facilities. 306 inline static oop obj_allocate(Klass* klass, int size, TRAPS); 307 inline static oop array_allocate(Klass* klass, int size, int length, TRAPS); 308 inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS); 309 inline static oop class_allocate(Klass* klass, int size, TRAPS); 310 311 // Raw memory allocation facilities 312 // The obj and array allocate methods are covers for these methods. 313 // mem_allocate() should never be 314 // called to allocate TLABs, only individual objects. 315 virtual HeapWord* mem_allocate(size_t size, 316 bool* gc_overhead_limit_was_exceeded) = 0; 317 318 // Utilities for turning raw memory into filler objects. 319 // 320 // min_fill_size() is the smallest region that can be filled. 321 // fill_with_objects() can fill arbitrary-sized regions of the heap using 322 // multiple objects. fill_with_object() is for regions known to be smaller 323 // than the largest array of integers; it uses a single object to fill the 324 // region and has slightly less overhead. 325 static size_t min_fill_size() { 326 return size_t(align_object_size(oopDesc::header_size())); 327 } 328 329 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); 330 331 static void fill_with_object(HeapWord* start, size_t words, bool zap = true); 332 static void fill_with_object(MemRegion region, bool zap = true) { 333 fill_with_object(region.start(), region.word_size(), zap); 334 } 335 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { 336 fill_with_object(start, pointer_delta(end, start), zap); 337 } 338 339 // Return the address "addr" aligned by "alignment_in_bytes" if such 340 // an address is below "end". Return NULL otherwise. 341 inline static HeapWord* align_allocation_or_fail(HeapWord* addr, 342 HeapWord* end, 343 unsigned short alignment_in_bytes); 344 345 // Some heaps may offer a contiguous region for shared non-blocking 346 // allocation, via inlined code (by exporting the address of the top and 347 // end fields defining the extent of the contiguous allocation region.) 348 349 // This function returns "true" iff the heap supports this kind of 350 // allocation. (Default is "no".) 351 virtual bool supports_inline_contig_alloc() const { 352 return false; 353 } 354 // These functions return the addresses of the fields that define the 355 // boundaries of the contiguous allocation area. (These fields should be 356 // physically near to one another.) 357 virtual HeapWord* volatile* top_addr() const { 358 guarantee(false, "inline contiguous allocation not supported"); 359 return NULL; 360 } 361 virtual HeapWord** end_addr() const { 362 guarantee(false, "inline contiguous allocation not supported"); 363 return NULL; 364 } 365 366 // Some heaps may be in an unparseable state at certain times between 367 // collections. This may be necessary for efficient implementation of 368 // certain allocation-related activities. Calling this function before 369 // attempting to parse a heap ensures that the heap is in a parsable 370 // state (provided other concurrent activity does not introduce 371 // unparsability). It is normally expected, therefore, that this 372 // method is invoked with the world stopped. 373 // NOTE: if you override this method, make sure you call 374 // super::ensure_parsability so that the non-generational 375 // part of the work gets done. See implementation of 376 // CollectedHeap::ensure_parsability and, for instance, 377 // that of GenCollectedHeap::ensure_parsability(). 378 // The argument "retire_tlabs" controls whether existing TLABs 379 // are merely filled or also retired, thus preventing further 380 // allocation from them and necessitating allocation of new TLABs. 381 virtual void ensure_parsability(bool retire_tlabs); 382 383 // Section on thread-local allocation buffers (TLABs) 384 // If the heap supports thread-local allocation buffers, it should override 385 // the following methods: 386 // Returns "true" iff the heap supports thread-local allocation buffers. 387 // The default is "no". 388 virtual bool supports_tlab_allocation() const = 0; 389 390 // The amount of space available for thread-local allocation buffers. 391 virtual size_t tlab_capacity(Thread *thr) const = 0; 392 393 // The amount of used space for thread-local allocation buffers for the given thread. 394 virtual size_t tlab_used(Thread *thr) const = 0; 395 396 virtual size_t max_tlab_size() const; 397 398 // An estimate of the maximum allocation that could be performed 399 // for thread-local allocation buffers without triggering any 400 // collection or expansion activity. 401 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { 402 guarantee(false, "thread-local allocation buffers not supported"); 403 return 0; 404 } 405 406 // Can a compiler initialize a new object without store barriers? 407 // This permission only extends from the creation of a new object 408 // via a TLAB up to the first subsequent safepoint. If such permission 409 // is granted for this heap type, the compiler promises to call 410 // defer_store_barrier() below on any slow path allocation of 411 // a new object for which such initializing store barriers will 412 // have been elided. 413 virtual bool can_elide_tlab_store_barriers() const = 0; 414 415 // If a compiler is eliding store barriers for TLAB-allocated objects, 416 // there is probably a corresponding slow path which can produce 417 // an object allocated anywhere. The compiler's runtime support 418 // promises to call this function on such a slow-path-allocated 419 // object before performing initializations that have elided 420 // store barriers. Returns new_obj, or maybe a safer copy thereof. 421 virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj); 422 423 // Answers whether an initializing store to a new object currently 424 // allocated at the given address doesn't need a store 425 // barrier. Returns "true" if it doesn't need an initializing 426 // store barrier; answers "false" if it does. 427 virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0; 428 429 // If a compiler is eliding store barriers for TLAB-allocated objects, 430 // we will be informed of a slow-path allocation by a call 431 // to new_store_pre_barrier() above. Such a call precedes the 432 // initialization of the object itself, and no post-store-barriers will 433 // be issued. Some heap types require that the barrier strictly follows 434 // the initializing stores. (This is currently implemented by deferring the 435 // barrier until the next slow-path allocation or gc-related safepoint.) 436 // This interface answers whether a particular heap type needs the card 437 // mark to be thus strictly sequenced after the stores. 438 virtual bool card_mark_must_follow_store() const = 0; 439 440 // If the CollectedHeap was asked to defer a store barrier above, 441 // this informs it to flush such a deferred store barrier to the 442 // remembered set. 443 virtual void flush_deferred_store_barrier(JavaThread* thread); 444 445 // Perform a collection of the heap; intended for use in implementing 446 // "System.gc". This probably implies as full a collection as the 447 // "CollectedHeap" supports. 448 virtual void collect(GCCause::Cause cause) = 0; 449 450 // Perform a full collection 451 virtual void do_full_collection(bool clear_all_soft_refs) = 0; 452 453 // This interface assumes that it's being called by the 454 // vm thread. It collects the heap assuming that the 455 // heap lock is already held and that we are executing in 456 // the context of the vm thread. 457 virtual void collect_as_vm_thread(GCCause::Cause cause); 458 459 // Returns the barrier set for this heap 460 BarrierSet* barrier_set() { return _barrier_set; } 461 void set_barrier_set(BarrierSet* barrier_set); 462 463 // Returns "true" iff there is a stop-world GC in progress. (I assume 464 // that it should answer "false" for the concurrent part of a concurrent 465 // collector -- dld). 466 bool is_gc_active() const { return _is_gc_active; } 467 468 // Total number of GC collections (started) 469 unsigned int total_collections() const { return _total_collections; } 470 unsigned int total_full_collections() const { return _total_full_collections;} 471 472 // Increment total number of GC collections (started) 473 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 474 void increment_total_collections(bool full = false) { 475 _total_collections++; 476 if (full) { 477 increment_total_full_collections(); 478 } 479 } 480 481 void increment_total_full_collections() { _total_full_collections++; } 482 483 // Return the AdaptiveSizePolicy for the heap. 484 virtual AdaptiveSizePolicy* size_policy() = 0; 485 486 // Return the CollectorPolicy for the heap 487 virtual CollectorPolicy* collector_policy() const = 0; 488 489 // Iterate over all objects, calling "cl.do_object" on each. 490 virtual void object_iterate(ObjectClosure* cl) = 0; 491 492 // Similar to object_iterate() except iterates only 493 // over live objects. 494 virtual void safe_object_iterate(ObjectClosure* cl) = 0; 495 496 // NOTE! There is no requirement that a collector implement these 497 // functions. 498 // 499 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 500 // each address in the (reserved) heap is a member of exactly 501 // one block. The defining characteristic of a block is that it is 502 // possible to find its size, and thus to progress forward to the next 503 // block. (Blocks may be of different sizes.) Thus, blocks may 504 // represent Java objects, or they might be free blocks in a 505 // free-list-based heap (or subheap), as long as the two kinds are 506 // distinguishable and the size of each is determinable. 507 508 // Returns the address of the start of the "block" that contains the 509 // address "addr". We say "blocks" instead of "object" since some heaps 510 // may not pack objects densely; a chunk may either be an object or a 511 // non-object. 512 virtual HeapWord* block_start(const void* addr) const = 0; 513 514 // Requires "addr" to be the start of a chunk, and returns its size. 515 // "addr + size" is required to be the start of a new chunk, or the end 516 // of the active area of the heap. 517 virtual size_t block_size(const HeapWord* addr) const = 0; 518 519 // Requires "addr" to be the start of a block, and returns "TRUE" iff 520 // the block is an object. 521 virtual bool block_is_obj(const HeapWord* addr) const = 0; 522 523 // Returns the longest time (in ms) that has elapsed since the last 524 // time that any part of the heap was examined by a garbage collection. 525 virtual jlong millis_since_last_gc() = 0; 526 527 // Perform any cleanup actions necessary before allowing a verification. 528 virtual void prepare_for_verify() = 0; 529 530 // Generate any dumps preceding or following a full gc 531 private: 532 void full_gc_dump(GCTimer* timer, bool before); 533 public: 534 void pre_full_gc_dump(GCTimer* timer); 535 void post_full_gc_dump(GCTimer* timer); 536 537 VirtualSpaceSummary create_heap_space_summary(); 538 GCHeapSummary create_heap_summary(); 539 540 MetaspaceSummary create_metaspace_summary(); 541 542 // Print heap information on the given outputStream. 543 virtual void print_on(outputStream* st) const = 0; 544 // The default behavior is to call print_on() on tty. 545 virtual void print() const { 546 print_on(tty); 547 } 548 // Print more detailed heap information on the given 549 // outputStream. The default behavior is to call print_on(). It is 550 // up to each subclass to override it and add any additional output 551 // it needs. 552 virtual void print_extended_on(outputStream* st) const { 553 print_on(st); 554 } 555 556 virtual void print_on_error(outputStream* st) const; 557 558 // Print all GC threads (other than the VM thread) 559 // used by this heap. 560 virtual void print_gc_threads_on(outputStream* st) const = 0; 561 // The default behavior is to call print_gc_threads_on() on tty. 562 void print_gc_threads() { 563 print_gc_threads_on(tty); 564 } 565 // Iterator for all GC threads (other than VM thread) 566 virtual void gc_threads_do(ThreadClosure* tc) const = 0; 567 568 // Print any relevant tracing info that flags imply. 569 // Default implementation does nothing. 570 virtual void print_tracing_info() const = 0; 571 572 void print_heap_before_gc(); 573 void print_heap_after_gc(); 574 575 // Registering and unregistering an nmethod (compiled code) with the heap. 576 // Override with specific mechanism for each specialized heap type. 577 virtual void register_nmethod(nmethod* nm); 578 virtual void unregister_nmethod(nmethod* nm); 579 580 void trace_heap_before_gc(const GCTracer* gc_tracer); 581 void trace_heap_after_gc(const GCTracer* gc_tracer); 582 583 // Heap verification 584 virtual void verify(VerifyOption option) = 0; 585 586 // Return true if concurrent phase control (via 587 // request_concurrent_phase_control) is supported by this collector. 588 // The default implementation returns false. 589 virtual bool supports_concurrent_phase_control() const; 590 591 // Return a NULL terminated array of concurrent phase names provided 592 // by this collector. Supports Whitebox testing. These are the 593 // names recognized by request_concurrent_phase(). The default 594 // implementation returns an array of one NULL element. 595 virtual const char* const* concurrent_phases() const; 596 597 // Request the collector enter the indicated concurrent phase, and 598 // wait until it does so. Supports WhiteBox testing. Only one 599 // request may be active at a time. Phases are designated by name; 600 // the set of names and their meaning is GC-specific. Once the 601 // requested phase has been reached, the collector will attempt to 602 // avoid transitioning to a new phase until a new request is made. 603 // [Note: A collector might not be able to remain in a given phase. 604 // For example, a full collection might cancel an in-progress 605 // concurrent collection.] 606 // 607 // Returns true when the phase is reached. Returns false for an 608 // unknown phase. The default implementation returns false. 609 virtual bool request_concurrent_phase(const char* phase); 610 611 // Non product verification and debugging. 612 #ifndef PRODUCT 613 // Support for PromotionFailureALot. Return true if it's time to cause a 614 // promotion failure. The no-argument version uses 615 // this->_promotion_failure_alot_count as the counter. 616 inline bool promotion_should_fail(volatile size_t* count); 617 inline bool promotion_should_fail(); 618 619 // Reset the PromotionFailureALot counters. Should be called at the end of a 620 // GC in which promotion failure occurred. 621 inline void reset_promotion_should_fail(volatile size_t* count); 622 inline void reset_promotion_should_fail(); 623 #endif // #ifndef PRODUCT 624 625 #ifdef ASSERT 626 static int fired_fake_oom() { 627 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); 628 } 629 #endif 630 631 public: 632 // Copy the current allocation context statistics for the specified contexts. 633 // For each context in contexts, set the corresponding entries in the totals 634 // and accuracy arrays to the current values held by the statistics. Each 635 // array should be of length len. 636 // Returns true if there are more stats available. 637 virtual bool copy_allocation_context_stats(const jint* contexts, 638 jlong* totals, 639 jbyte* accuracy, 640 jint len) { 641 return false; 642 } 643 644 }; 645 646 // Class to set and reset the GC cause for a CollectedHeap. 647 648 class GCCauseSetter : StackObj { 649 CollectedHeap* _heap; 650 GCCause::Cause _previous_cause; 651 public: 652 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { 653 assert(SafepointSynchronize::is_at_safepoint(), 654 "This method manipulates heap state without locking"); 655 _heap = heap; 656 _previous_cause = _heap->gc_cause(); 657 _heap->set_gc_cause(cause); 658 } 659 660 ~GCCauseSetter() { 661 assert(SafepointSynchronize::is_at_safepoint(), 662 "This method manipulates heap state without locking"); 663 _heap->set_gc_cause(_previous_cause); 664 } 665 }; 666 667 #endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP