1 /* 2 * Copyright (c) 2001, 2014, 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_INTERFACE_COLLECTEDHEAP_HPP 26 #define SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP 27 28 #include "gc_interface/gcCause.hpp" 29 #include "gc_implementation/shared/gcWhen.hpp" 30 #include "memory/allocation.hpp" 31 #include "memory/barrierSet.hpp" 32 #include "runtime/handles.hpp" 33 #include "runtime/perfData.hpp" 34 #include "runtime/safepoint.hpp" 35 #include "utilities/events.hpp" 36 37 // A "CollectedHeap" is an implementation of a java heap for HotSpot. This 38 // is an abstract class: there may be many different kinds of heaps. This 39 // class defines the functions that a heap must implement, and contains 40 // infrastructure common to all heaps. 41 42 class AdaptiveSizePolicy; 43 class BarrierSet; 44 class CollectorPolicy; 45 class GCHeapSummary; 46 class GCTimer; 47 class GCTracer; 48 class MetaspaceSummary; 49 class Thread; 50 class ThreadClosure; 51 class VirtualSpaceSummary; 52 class nmethod; 53 54 class GCMessage : public FormatBuffer<1024> { 55 public: 56 bool is_before; 57 58 public: 59 GCMessage() {} 60 }; 61 62 class GCHeapLog : public EventLogBase<GCMessage> { 63 private: 64 void log_heap(bool before); 65 66 public: 67 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {} 68 69 void log_heap_before() { 70 log_heap(true); 71 } 72 void log_heap_after() { 73 log_heap(false); 74 } 75 }; 76 77 // 78 // CollectedHeap 79 // SharedHeap 80 // GenCollectedHeap 81 // G1CollectedHeap 82 // ShenandoahHeap 83 // ParallelScavengeHeap 84 // 85 class CollectedHeap : public CHeapObj<mtInternal> { 86 friend class VMStructs; 87 friend class IsGCActiveMark; // Block structured external access to _is_gc_active 88 89 #ifdef ASSERT 90 static int _fire_out_of_memory_count; 91 #endif 92 93 // Used for filler objects (static, but initialized in ctor). 94 static size_t _filler_array_max_size; 95 96 GCHeapLog* _gc_heap_log; 97 98 // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 is being used 99 bool _defer_initial_card_mark; 100 101 protected: 102 MemRegion _reserved; 103 BarrierSet* _barrier_set; 104 bool _is_gc_active; 105 uint _n_par_threads; 106 107 unsigned int _total_collections; // ... started 108 unsigned int _total_full_collections; // ... started 109 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) 110 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) 111 112 // Reason for current garbage collection. Should be set to 113 // a value reflecting no collection between collections. 114 GCCause::Cause _gc_cause; 115 GCCause::Cause _gc_lastcause; 116 PerfStringVariable* _perf_gc_cause; 117 PerfStringVariable* _perf_gc_lastcause; 118 119 // Constructor 120 CollectedHeap(); 121 122 // Do common initializations that must follow instance construction, 123 // for example, those needing virtual calls. 124 // This code could perhaps be moved into initialize() but would 125 // be slightly more awkward because we want the latter to be a 126 // pure virtual. 127 void pre_initialize(); 128 129 // Create a new tlab. All TLAB allocations must go through this. 130 virtual HeapWord* allocate_new_tlab(size_t size); 131 132 // Accumulate statistics on all tlabs. 133 virtual void accumulate_statistics_all_tlabs(); 134 135 // Reinitialize tlabs before resuming mutators. 136 virtual void resize_all_tlabs(); 137 138 // Allocate from the current thread's TLAB, with broken-out slow path. 139 inline static HeapWord* allocate_from_tlab(KlassHandle klass, Thread* thread, size_t size); 140 static HeapWord* allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size); 141 142 // Allocate an uninitialized block of the given size, or returns NULL if 143 // this is impossible. 144 inline static HeapWord* common_mem_allocate_noinit(KlassHandle klass, size_t size, TRAPS); 145 146 // Like allocate_init, but the block returned by a successful allocation 147 // is guaranteed initialized to zeros. 148 inline static HeapWord* common_mem_allocate_init(KlassHandle klass, size_t size, TRAPS); 149 150 // Helper functions for (VM) allocation. 151 inline static void post_allocation_setup_common(KlassHandle klass, HeapWord* obj); 152 inline static void post_allocation_setup_no_klass_install(KlassHandle klass, 153 HeapWord* objPtr); 154 155 inline static void post_allocation_setup_obj(KlassHandle klass, HeapWord* obj, int size); 156 157 inline static void post_allocation_setup_array(KlassHandle klass, 158 HeapWord* obj, int length); 159 160 // Clears an allocated object. 161 inline static void init_obj(HeapWord* obj, size_t size); 162 163 // Filler object utilities. 164 static inline size_t filler_array_hdr_size(); 165 static inline size_t filler_array_min_size(); 166 167 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) 168 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) 169 170 // Fill with a single array; caller must ensure filler_array_min_size() <= 171 // words <= filler_array_max_size(). 172 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); 173 174 // Fill with a single object (either an int array or a java.lang.Object). 175 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); 176 177 virtual void trace_heap(GCWhen::Type when, GCTracer* tracer); 178 179 // Verification functions 180 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) 181 PRODUCT_RETURN; 182 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) 183 PRODUCT_RETURN; 184 debug_only(static void check_for_valid_allocation_state();) 185 186 public: 187 enum Name { 188 Abstract, 189 SharedHeap, 190 GenCollectedHeap, 191 ParallelScavengeHeap, 192 G1CollectedHeap, 193 ShenandoahHeap 194 }; 195 196 static inline size_t filler_array_max_size() { 197 return _filler_array_max_size; 198 } 199 200 virtual CollectedHeap::Name kind() const { return CollectedHeap::Abstract; } 201 202 virtual HeapWord* tlab_post_allocation_setup(HeapWord* obj); 203 204 /** 205 * Returns JNI error code JNI_ENOMEM if memory could not be allocated, 206 * and JNI_OK on success. 207 */ 208 virtual jint initialize() = 0; 209 210 // In many heaps, there will be a need to perform some initialization activities 211 // after the Universe is fully formed, but before general heap allocation is allowed. 212 // This is the correct place to place such initialization methods. 213 virtual void post_initialize() = 0; 214 215 // Stop any onging concurrent work and prepare for exit. 216 virtual void stop() {} 217 218 MemRegion reserved_region() const { return _reserved; } 219 address base() const { return (address)reserved_region().start(); } 220 221 virtual size_t capacity() const = 0; 222 virtual size_t used() const = 0; 223 224 // Return "true" if the part of the heap that allocates Java 225 // objects has reached the maximal committed limit that it can 226 // reach, without a garbage collection. 227 virtual bool is_maximal_no_gc() const = 0; 228 229 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of 230 // memory that the vm could make available for storing 'normal' java objects. 231 // This is based on the reserved address space, but should not include space 232 // that the vm uses internally for bookkeeping or temporary storage 233 // (e.g., in the case of the young gen, one of the survivor 234 // spaces). 235 virtual size_t max_capacity() const = 0; 236 237 // Returns "TRUE" if "p" points into the reserved area of the heap. 238 bool is_in_reserved(const void* p) const { 239 return _reserved.contains(p); 240 } 241 242 bool is_in_reserved_or_null(const void* p) const { 243 return p == NULL || is_in_reserved(p); 244 } 245 246 // Returns "TRUE" iff "p" points into the committed areas of the heap. 247 // Since this method can be expensive in general, we restrict its 248 // use to assertion checking only. 249 virtual bool is_in(const void* p) const = 0; 250 251 bool is_in_or_null(const void* p) const { 252 return p == NULL || is_in(p); 253 } 254 255 bool is_in_place(Metadata** p) { 256 return !Universe::heap()->is_in(p); 257 } 258 bool is_in_place(oop* p) { return Universe::heap()->is_in(p); } 259 bool is_in_place(narrowOop* p) { 260 oop o = oopDesc::load_decode_heap_oop_not_null(p); 261 return Universe::heap()->is_in((const void*)o); 262 } 263 264 // Let's define some terms: a "closed" subset of a heap is one that 265 // 266 // 1) contains all currently-allocated objects, and 267 // 268 // 2) is closed under reference: no object in the closed subset 269 // references one outside the closed subset. 270 // 271 // Membership in a heap's closed subset is useful for assertions. 272 // Clearly, the entire heap is a closed subset, so the default 273 // implementation is to use "is_in_reserved". But this may not be too 274 // liberal to perform useful checking. Also, the "is_in" predicate 275 // defines a closed subset, but may be too expensive, since "is_in" 276 // verifies that its argument points to an object head. The 277 // "closed_subset" method allows a heap to define an intermediate 278 // predicate, allowing more precise checking than "is_in_reserved" at 279 // lower cost than "is_in." 280 281 // One important case is a heap composed of disjoint contiguous spaces, 282 // such as the Garbage-First collector. Such heaps have a convenient 283 // closed subset consisting of the allocated portions of those 284 // contiguous spaces. 285 286 // Return "TRUE" iff the given pointer points into the heap's defined 287 // closed subset (which defaults to the entire heap). 288 virtual bool is_in_closed_subset(const void* p) const { 289 return is_in_reserved(p); 290 } 291 292 bool is_in_closed_subset_or_null(const void* p) const { 293 return p == NULL || is_in_closed_subset(p); 294 } 295 296 #ifdef ASSERT 297 // Returns true if "p" is in the part of the 298 // heap being collected. 299 virtual bool is_in_partial_collection(const void *p) = 0; 300 #endif 301 302 // An object is scavengable if its location may move during a scavenge. 303 // (A scavenge is a GC which is not a full GC.) 304 virtual bool is_scavengable(const void *p) = 0; 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 // Number of threads currently working on GC tasks. 317 uint n_par_threads() { return _n_par_threads; } 318 319 // May be overridden to set additional parallelism. 320 virtual void set_par_threads(uint t) { _n_par_threads = t; }; 321 322 // General obj/array allocation facilities. 323 inline static oop obj_allocate(KlassHandle klass, int size, TRAPS); 324 inline static oop array_allocate(KlassHandle klass, int size, int length, TRAPS); 325 inline static oop array_allocate_nozero(KlassHandle klass, int size, int length, TRAPS); 326 327 inline static void post_allocation_install_obj_klass(KlassHandle klass, 328 oop obj); 329 330 virtual uint oop_extra_words(); 331 332 #ifndef CC_INTERP 333 virtual void compile_prepare_oop(MacroAssembler* masm, Register obj); 334 #endif 335 336 // Raw memory allocation facilities 337 // The obj and array allocate methods are covers for these methods. 338 // mem_allocate() should never be 339 // called to allocate TLABs, only individual objects. 340 virtual HeapWord* mem_allocate(size_t size, 341 bool* gc_overhead_limit_was_exceeded) = 0; 342 343 // Utilities for turning raw memory into filler objects. 344 // 345 // min_fill_size() is the smallest region that can be filled. 346 // fill_with_objects() can fill arbitrary-sized regions of the heap using 347 // multiple objects. fill_with_object() is for regions known to be smaller 348 // than the largest array of integers; it uses a single object to fill the 349 // region and has slightly less overhead. 350 static size_t min_fill_size() { 351 return size_t(align_object_size(oopDesc::header_size())); 352 } 353 354 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); 355 356 static void fill_with_object(HeapWord* start, size_t words, bool zap = true); 357 static void fill_with_object(MemRegion region, bool zap = true) { 358 fill_with_object(region.start(), region.word_size(), zap); 359 } 360 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { 361 fill_with_object(start, pointer_delta(end, start), zap); 362 } 363 364 // Return the address "addr" aligned by "alignment_in_bytes" if such 365 // an address is below "end". Return NULL otherwise. 366 inline static HeapWord* align_allocation_or_fail(HeapWord* addr, 367 HeapWord* end, 368 unsigned short alignment_in_bytes); 369 370 // Some heaps may offer a contiguous region for shared non-blocking 371 // allocation, via inlined code (by exporting the address of the top and 372 // end fields defining the extent of the contiguous allocation region.) 373 374 // This function returns "true" iff the heap supports this kind of 375 // allocation. (Default is "no".) 376 virtual bool supports_inline_contig_alloc() const { 377 return false; 378 } 379 // These functions return the addresses of the fields that define the 380 // boundaries of the contiguous allocation area. (These fields should be 381 // physically near to one another.) 382 virtual HeapWord** top_addr() const { 383 guarantee(false, "inline contiguous allocation not supported"); 384 return NULL; 385 } 386 virtual HeapWord** end_addr() const { 387 guarantee(false, "inline contiguous allocation not supported"); 388 return NULL; 389 } 390 391 // Some heaps may be in an unparseable state at certain times between 392 // collections. This may be necessary for efficient implementation of 393 // certain allocation-related activities. Calling this function before 394 // attempting to parse a heap ensures that the heap is in a parsable 395 // state (provided other concurrent activity does not introduce 396 // unparsability). It is normally expected, therefore, that this 397 // method is invoked with the world stopped. 398 // NOTE: if you override this method, make sure you call 399 // super::ensure_parsability so that the non-generational 400 // part of the work gets done. See implementation of 401 // CollectedHeap::ensure_parsability and, for instance, 402 // that of GenCollectedHeap::ensure_parsability(). 403 // The argument "retire_tlabs" controls whether existing TLABs 404 // are merely filled or also retired, thus preventing further 405 // allocation from them and necessitating allocation of new TLABs. 406 virtual void ensure_parsability(bool retire_tlabs); 407 408 // Section on thread-local allocation buffers (TLABs) 409 // If the heap supports thread-local allocation buffers, it should override 410 // the following methods: 411 // Returns "true" iff the heap supports thread-local allocation buffers. 412 // The default is "no". 413 virtual bool supports_tlab_allocation() const = 0; 414 415 // The amount of space available for thread-local allocation buffers. 416 virtual size_t tlab_capacity(Thread *thr) const = 0; 417 418 // The amount of used space for thread-local allocation buffers for the given thread. 419 virtual size_t tlab_used(Thread *thr) const = 0; 420 421 virtual size_t max_tlab_size() const; 422 423 // An estimate of the maximum allocation that could be performed 424 // for thread-local allocation buffers without triggering any 425 // collection or expansion activity. 426 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { 427 guarantee(false, "thread-local allocation buffers not supported"); 428 return 0; 429 } 430 431 // Can a compiler initialize a new object without store barriers? 432 // This permission only extends from the creation of a new object 433 // via a TLAB up to the first subsequent safepoint. If such permission 434 // is granted for this heap type, the compiler promises to call 435 // defer_store_barrier() below on any slow path allocation of 436 // a new object for which such initializing store barriers will 437 // have been elided. 438 virtual bool can_elide_tlab_store_barriers() const = 0; 439 440 // If a compiler is eliding store barriers for TLAB-allocated objects, 441 // there is probably a corresponding slow path which can produce 442 // an object allocated anywhere. The compiler's runtime support 443 // promises to call this function on such a slow-path-allocated 444 // object before performing initializations that have elided 445 // store barriers. Returns new_obj, or maybe a safer copy thereof. 446 virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj); 447 448 // Answers whether an initializing store to a new object currently 449 // allocated at the given address doesn't need a store 450 // barrier. Returns "true" if it doesn't need an initializing 451 // store barrier; answers "false" if it does. 452 virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0; 453 454 // If a compiler is eliding store barriers for TLAB-allocated objects, 455 // we will be informed of a slow-path allocation by a call 456 // to new_store_pre_barrier() above. Such a call precedes the 457 // initialization of the object itself, and no post-store-barriers will 458 // be issued. Some heap types require that the barrier strictly follows 459 // the initializing stores. (This is currently implemented by deferring the 460 // barrier until the next slow-path allocation or gc-related safepoint.) 461 // This interface answers whether a particular heap type needs the card 462 // mark to be thus strictly sequenced after the stores. 463 virtual bool card_mark_must_follow_store() const = 0; 464 465 // If the CollectedHeap was asked to defer a store barrier above, 466 // this informs it to flush such a deferred store barrier to the 467 // remembered set. 468 virtual void flush_deferred_store_barrier(JavaThread* thread); 469 470 // Does this heap support heap inspection (+PrintClassHistogram?) 471 virtual bool supports_heap_inspection() const = 0; 472 473 // Perform a collection of the heap; intended for use in implementing 474 // "System.gc". This probably implies as full a collection as the 475 // "CollectedHeap" supports. 476 virtual void collect(GCCause::Cause cause) = 0; 477 478 // Perform a full collection 479 virtual void do_full_collection(bool clear_all_soft_refs) = 0; 480 481 // This interface assumes that it's being called by the 482 // vm thread. It collects the heap assuming that the 483 // heap lock is already held and that we are executing in 484 // the context of the vm thread. 485 virtual void collect_as_vm_thread(GCCause::Cause cause); 486 487 // Returns the barrier set for this heap 488 BarrierSet* barrier_set() { return _barrier_set; } 489 490 // Returns "true" iff there is a stop-world GC in progress. (I assume 491 // that it should answer "false" for the concurrent part of a concurrent 492 // collector -- dld). 493 bool is_gc_active() const { return _is_gc_active; } 494 495 // Total number of GC collections (started) 496 unsigned int total_collections() const { return _total_collections; } 497 unsigned int total_full_collections() const { return _total_full_collections;} 498 499 // Increment total number of GC collections (started) 500 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 501 void increment_total_collections(bool full = false) { 502 _total_collections++; 503 if (full) { 504 increment_total_full_collections(); 505 } 506 } 507 508 void increment_total_full_collections() { _total_full_collections++; } 509 510 // Return the AdaptiveSizePolicy for the heap. 511 virtual AdaptiveSizePolicy* size_policy() = 0; 512 513 // Return the CollectorPolicy for the heap 514 virtual CollectorPolicy* collector_policy() const = 0; 515 516 void oop_iterate_no_header(OopClosure* cl); 517 518 // Iterate over all the ref-containing fields of all objects, calling 519 // "cl.do_oop" on each. 520 virtual void oop_iterate(ExtendedOopClosure* cl) = 0; 521 522 // Iterate over all objects, calling "cl.do_object" on each. 523 virtual void object_iterate(ObjectClosure* cl) = 0; 524 525 // Similar to object_iterate() except iterates only 526 // over live objects. 527 virtual void safe_object_iterate(ObjectClosure* cl) = 0; 528 529 // NOTE! There is no requirement that a collector implement these 530 // functions. 531 // 532 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 533 // each address in the (reserved) heap is a member of exactly 534 // one block. The defining characteristic of a block is that it is 535 // possible to find its size, and thus to progress forward to the next 536 // block. (Blocks may be of different sizes.) Thus, blocks may 537 // represent Java objects, or they might be free blocks in a 538 // free-list-based heap (or subheap), as long as the two kinds are 539 // distinguishable and the size of each is determinable. 540 541 // Returns the address of the start of the "block" that contains the 542 // address "addr". We say "blocks" instead of "object" since some heaps 543 // may not pack objects densely; a chunk may either be an object or a 544 // non-object. 545 virtual HeapWord* block_start(const void* addr) const = 0; 546 547 // Requires "addr" to be the start of a chunk, and returns its size. 548 // "addr + size" is required to be the start of a new chunk, or the end 549 // of the active area of the heap. 550 virtual size_t block_size(const HeapWord* addr) const = 0; 551 552 // Requires "addr" to be the start of a block, and returns "TRUE" iff 553 // the block is an object. 554 virtual bool block_is_obj(const HeapWord* addr) const = 0; 555 556 // Returns the longest time (in ms) that has elapsed since the last 557 // time that any part of the heap was examined by a garbage collection. 558 virtual jlong millis_since_last_gc() = 0; 559 560 // Perform any cleanup actions necessary before allowing a verification. 561 virtual void prepare_for_verify() = 0; 562 563 // Generate any dumps preceding or following a full gc 564 void pre_full_gc_dump(GCTimer* timer); 565 void post_full_gc_dump(GCTimer* timer); 566 567 VirtualSpaceSummary create_heap_space_summary(); 568 GCHeapSummary create_heap_summary(); 569 570 MetaspaceSummary create_metaspace_summary(); 571 572 // Print heap information on the given outputStream. 573 virtual void print_on(outputStream* st) const = 0; 574 // The default behavior is to call print_on() on tty. 575 virtual void print() const { 576 print_on(tty); 577 } 578 // Print more detailed heap information on the given 579 // outputStream. The default behavior is to call print_on(). It is 580 // up to each subclass to override it and add any additional output 581 // it needs. 582 virtual void print_extended_on(outputStream* st) const { 583 print_on(st); 584 } 585 586 virtual void print_on_error(outputStream* st) const { 587 st->print_cr("Heap:"); 588 print_extended_on(st); 589 st->cr(); 590 591 _barrier_set->print_on(st); 592 } 593 594 // Print all GC threads (other than the VM thread) 595 // used by this heap. 596 virtual void print_gc_threads_on(outputStream* st) const = 0; 597 // The default behavior is to call print_gc_threads_on() on tty. 598 void print_gc_threads() { 599 print_gc_threads_on(tty); 600 } 601 // Iterator for all GC threads (other than VM thread) 602 virtual void gc_threads_do(ThreadClosure* tc) const = 0; 603 604 // Print any relevant tracing info that flags imply. 605 // Default implementation does nothing. 606 virtual void print_tracing_info() const = 0; 607 608 void print_heap_before_gc(); 609 void print_heap_after_gc(); 610 611 // Registering and unregistering an nmethod (compiled code) with the heap. 612 // Override with specific mechanism for each specialized heap type. 613 virtual void register_nmethod(nmethod* nm); 614 virtual void unregister_nmethod(nmethod* nm); 615 616 void trace_heap_before_gc(GCTracer* gc_tracer); 617 void trace_heap_after_gc(GCTracer* gc_tracer); 618 619 // Heap verification 620 virtual void verify(bool silent, VerifyOption option) = 0; 621 622 // Shut down all GC workers and other GC related threads. 623 virtual void shutdown(); 624 625 // Accumulate additional statistics from GCLABs. 626 virtual void accumulate_statistics_all_gclabs(); 627 628 // Support for object pinning. This is used by JNI Get*Critical() 629 // and Release*Critical() family of functions. If supported, the GC 630 // must guarantee that pinned objects never move. 631 virtual bool supports_object_pinning() const; 632 virtual oop pin_object(JavaThread* thread, oop obj); 633 virtual void unpin_object(JavaThread* thread, oop obj); 634 635 // Non product verification and debugging. 636 #ifndef PRODUCT 637 // Support for PromotionFailureALot. Return true if it's time to cause a 638 // promotion failure. The no-argument version uses 639 // this->_promotion_failure_alot_count as the counter. 640 inline bool promotion_should_fail(volatile size_t* count); 641 inline bool promotion_should_fail(); 642 643 // Reset the PromotionFailureALot counters. Should be called at the end of a 644 // GC in which promotion failure occurred. 645 inline void reset_promotion_should_fail(volatile size_t* count); 646 inline void reset_promotion_should_fail(); 647 #endif // #ifndef PRODUCT 648 649 #ifdef ASSERT 650 static int fired_fake_oom() { 651 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); 652 } 653 #endif 654 655 public: 656 // This is a convenience method that is used in cases where 657 // the actual number of GC worker threads is not pertinent but 658 // only whether there more than 0. Use of this method helps 659 // reduce the occurrence of ParallelGCThreads to uses where the 660 // actual number may be germane. 661 static bool use_parallel_gc_threads() { return ParallelGCThreads > 0; } 662 663 // Copy the current allocation context statistics for the specified contexts. 664 // For each context in contexts, set the corresponding entries in the totals 665 // and accuracy arrays to the current values held by the statistics. Each 666 // array should be of length len. 667 // Returns true if there are more stats available. 668 virtual bool copy_allocation_context_stats(const jint* contexts, 669 jlong* totals, 670 jbyte* accuracy, 671 jint len) { 672 return false; 673 } 674 675 /////////////// Unit tests /////////////// 676 677 NOT_PRODUCT(static void test_is_in();) 678 }; 679 680 // Class to set and reset the GC cause for a CollectedHeap. 681 682 class GCCauseSetter : StackObj { 683 CollectedHeap* _heap; 684 GCCause::Cause _previous_cause; 685 public: 686 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { 687 assert(SafepointSynchronize::is_at_safepoint(), 688 "This method manipulates heap state without locking"); 689 _heap = heap; 690 _previous_cause = _heap->gc_cause(); 691 _heap->set_gc_cause(cause); 692 } 693 694 ~GCCauseSetter() { 695 assert(SafepointSynchronize::is_at_safepoint(), 696 "This method manipulates heap state without locking"); 697 _heap->set_gc_cause(_previous_cause); 698 } 699 }; 700 701 #endif // SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP