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
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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 // ZCollectedHeap
93 //
94 class CollectedHeap : public CHeapObj<mtInternal> {
95 friend class VMStructs;
96 friend class JVMCIVMStructs;
97 friend class IsGCActiveMark; // Block structured external access to _is_gc_active
98
99 private:
100 #ifdef ASSERT
101 static int _fire_out_of_memory_count;
102 #endif
103
104 GCHeapLog* _gc_heap_log;
105
106 MemRegion _reserved;
107
108 protected:
109 bool _is_gc_active;
110
111 // Used for filler objects (static, but initialized in ctor).
112 static size_t _filler_array_max_size;
113
114 unsigned int _total_collections; // ... started
115 unsigned int _total_full_collections; // ... started
116 NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;)
117 NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;)
118
119 // Reason for current garbage collection. Should be set to
120 // a value reflecting no collection between collections.
121 GCCause::Cause _gc_cause;
122 GCCause::Cause _gc_lastcause;
123 PerfStringVariable* _perf_gc_cause;
124 PerfStringVariable* _perf_gc_lastcause;
125
126 // Constructor
127 CollectedHeap();
128
129 // Create a new tlab. All TLAB allocations must go through this.
130 // To allow more flexible TLAB allocations min_size specifies
131 // the minimum size needed, while requested_size is the requested
132 // size based on ergonomics. The actually allocated size will be
133 // returned in actual_size.
134 virtual HeapWord* allocate_new_tlab(size_t min_size,
135 size_t requested_size,
136 size_t* actual_size);
137
138 // Accumulate statistics on all tlabs.
139 virtual void accumulate_statistics_all_tlabs();
140
141 // Reinitialize tlabs before resuming mutators.
142 virtual void resize_all_tlabs();
143
144 // Allocate from the current thread's TLAB, with broken-out slow path.
145 inline static HeapWord* allocate_from_tlab(Klass* klass, size_t size, TRAPS);
146 static HeapWord* allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS);
147
148 inline static HeapWord* allocate_outside_tlab(Klass* klass, size_t size,
149 bool* gc_overhead_limit_was_exceeded, TRAPS);
150
151 // Raw memory allocation facilities
152 // The obj and array allocate methods are covers for these methods.
153 // mem_allocate() should never be
154 // called to allocate TLABs, only individual objects.
155 virtual HeapWord* mem_allocate(size_t size,
156 bool* gc_overhead_limit_was_exceeded) = 0;
157
158 // Allocate an uninitialized block of the given size, or returns NULL if
159 // this is impossible.
160 inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS);
161
162 // Like allocate_init, but the block returned by a successful allocation
163 // is guaranteed initialized to zeros.
164 inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS);
165
166 // Helper functions for (VM) allocation.
167 inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj);
168 inline static void post_allocation_setup_no_klass_install(Klass* klass,
169 HeapWord* objPtr);
170
171 inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size);
172
173 inline static void post_allocation_setup_array(Klass* klass,
174 HeapWord* obj, int length);
175
176 inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size);
177
178 // Clears an allocated object.
179 inline static void init_obj(HeapWord* obj, size_t size);
180
181 // Filler object utilities.
182 static inline size_t filler_array_hdr_size();
183 static inline size_t filler_array_min_size();
184
185 DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
186 DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);)
187
188 // Fill with a single array; caller must ensure filler_array_min_size() <=
189 // words <= filler_array_max_size().
190 static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true);
191
192 // Fill with a single object (either an int array or a java.lang.Object).
193 static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true);
194
195 virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer);
196
197 // Verification functions
198 virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
199 PRODUCT_RETURN;
200 virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)
201 PRODUCT_RETURN;
202 debug_only(static void check_for_valid_allocation_state();)
203
204 public:
205 enum Name {
206 None,
207 Serial,
208 Parallel,
209 CMS,
210 G1,
211 Z
212 };
213
214 static inline size_t filler_array_max_size() {
215 return _filler_array_max_size;
216 }
217
218 virtual Name kind() const = 0;
219
220 virtual const char* name() const = 0;
221
222 /**
223 * Returns JNI error code JNI_ENOMEM if memory could not be allocated,
224 * and JNI_OK on success.
225 */
226 virtual jint initialize() = 0;
227
228 // In many heaps, there will be a need to perform some initialization activities
229 // after the Universe is fully formed, but before general heap allocation is allowed.
230 // This is the correct place to place such initialization methods.
231 virtual void post_initialize();
232
233 // Stop any onging concurrent work and prepare for exit.
234 virtual void stop() {}
235
236 // Stop and resume concurrent GC threads interfering with safepoint operations
237 virtual void safepoint_synchronize_begin() {}
238 virtual void safepoint_synchronize_end() {}
239
240 void initialize_reserved_region(HeapWord *start, HeapWord *end);
241 MemRegion reserved_region() const { return _reserved; }
242 address base() const { return (address)reserved_region().start(); }
243
244 virtual size_t capacity() const = 0;
245 virtual size_t used() const = 0;
246
247 // Return "true" if the part of the heap that allocates Java
248 // objects has reached the maximal committed limit that it can
249 // reach, without a garbage collection.
250 virtual bool is_maximal_no_gc() const = 0;
251
252 // Support for java.lang.Runtime.maxMemory(): return the maximum amount of
253 // memory that the vm could make available for storing 'normal' java objects.
254 // This is based on the reserved address space, but should not include space
255 // that the vm uses internally for bookkeeping or temporary storage
256 // (e.g., in the case of the young gen, one of the survivor
257 // spaces).
258 virtual size_t max_capacity() const = 0;
259
260 // Returns "TRUE" if "p" points into the reserved area of the heap.
261 bool is_in_reserved(const void* p) const {
262 return _reserved.contains(p);
263 }
264
265 bool is_in_reserved_or_null(const void* p) const {
266 return p == NULL || is_in_reserved(p);
267 }
268
269 // Returns "TRUE" iff "p" points into the committed areas of the heap.
270 // This method can be expensive so avoid using it in performance critical
271 // code.
272 virtual bool is_in(const void* p) const = 0;
273
274 DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); })
275
276 // Let's define some terms: a "closed" subset of a heap is one that
277 //
278 // 1) contains all currently-allocated objects, and
279 //
280 // 2) is closed under reference: no object in the closed subset
281 // references one outside the closed subset.
282 //
283 // Membership in a heap's closed subset is useful for assertions.
284 // Clearly, the entire heap is a closed subset, so the default
285 // implementation is to use "is_in_reserved". But this may not be too
286 // liberal to perform useful checking. Also, the "is_in" predicate
287 // defines a closed subset, but may be too expensive, since "is_in"
288 // verifies that its argument points to an object head. The
289 // "closed_subset" method allows a heap to define an intermediate
290 // predicate, allowing more precise checking than "is_in_reserved" at
291 // lower cost than "is_in."
292
293 // One important case is a heap composed of disjoint contiguous spaces,
294 // such as the Garbage-First collector. Such heaps have a convenient
295 // closed subset consisting of the allocated portions of those
296 // contiguous spaces.
297
298 // Return "TRUE" iff the given pointer points into the heap's defined
299 // closed subset (which defaults to the entire heap).
300 virtual bool is_in_closed_subset(const void* p) const {
301 return is_in_reserved(p);
302 }
303
304 bool is_in_closed_subset_or_null(const void* p) const {
305 return p == NULL || is_in_closed_subset(p);
306 }
307
308 void set_gc_cause(GCCause::Cause v) {
309 if (UsePerfData) {
310 _gc_lastcause = _gc_cause;
311 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
312 _perf_gc_cause->set_value(GCCause::to_string(v));
313 }
314 _gc_cause = v;
315 }
316 GCCause::Cause gc_cause() { return _gc_cause; }
317
318 // General obj/array allocation facilities.
319 inline static oop obj_allocate(Klass* klass, int size, TRAPS);
320 inline static oop array_allocate(Klass* klass, int size, int length, TRAPS);
321 inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS);
322 inline static oop class_allocate(Klass* klass, int size, TRAPS);
323
324 // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
325 // allocation. A GC implementation may override this function to satisfy the allocation
326 // in any way. But the default is to try a TLAB allocation, and otherwise perform
327 // mem_allocate.
328 virtual HeapWord* obj_allocate_raw(Klass* klass, size_t size,
329 bool* gc_overhead_limit_was_exceeded, TRAPS);
330
331 // Utilities for turning raw memory into filler objects.
332 //
333 // min_fill_size() is the smallest region that can be filled.
334 // fill_with_objects() can fill arbitrary-sized regions of the heap using
335 // multiple objects. fill_with_object() is for regions known to be smaller
336 // than the largest array of integers; it uses a single object to fill the
337 // region and has slightly less overhead.
338 static size_t min_fill_size() {
339 return size_t(align_object_size(oopDesc::header_size()));
340 }
341
342 static void fill_with_objects(HeapWord* start, size_t words, bool zap = true);
343
344 static void fill_with_object(HeapWord* start, size_t words, bool zap = true);
345 static void fill_with_object(MemRegion region, bool zap = true) {
346 fill_with_object(region.start(), region.word_size(), zap);
347 }
348 static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) {
349 fill_with_object(start, pointer_delta(end, start), zap);
350 }
351
352 // Return the address "addr" aligned by "alignment_in_bytes" if such
353 // an address is below "end". Return NULL otherwise.
354 inline static HeapWord* align_allocation_or_fail(HeapWord* addr,
355 HeapWord* end,
356 unsigned short alignment_in_bytes);
357
358 // Some heaps may offer a contiguous region for shared non-blocking
359 // allocation, via inlined code (by exporting the address of the top and
360 // end fields defining the extent of the contiguous allocation region.)
361
362 // This function returns "true" iff the heap supports this kind of
363 // allocation. (Default is "no".)
364 virtual bool supports_inline_contig_alloc() const {
365 return false;
366 }
367 // These functions return the addresses of the fields that define the
368 // boundaries of the contiguous allocation area. (These fields should be
369 // physically near to one another.)
370 virtual HeapWord* volatile* top_addr() const {
371 guarantee(false, "inline contiguous allocation not supported");
372 return NULL;
373 }
374 virtual HeapWord** end_addr() const {
375 guarantee(false, "inline contiguous allocation not supported");
376 return NULL;
377 }
378
379 // Some heaps may be in an unparseable state at certain times between
380 // collections. This may be necessary for efficient implementation of
381 // certain allocation-related activities. Calling this function before
382 // attempting to parse a heap ensures that the heap is in a parsable
383 // state (provided other concurrent activity does not introduce
384 // unparsability). It is normally expected, therefore, that this
385 // method is invoked with the world stopped.
386 // NOTE: if you override this method, make sure you call
387 // super::ensure_parsability so that the non-generational
388 // part of the work gets done. See implementation of
389 // CollectedHeap::ensure_parsability and, for instance,
390 // that of GenCollectedHeap::ensure_parsability().
391 // The argument "retire_tlabs" controls whether existing TLABs
392 // are merely filled or also retired, thus preventing further
393 // allocation from them and necessitating allocation of new TLABs.
394 virtual void ensure_parsability(bool retire_tlabs);
395
396 // Section on thread-local allocation buffers (TLABs)
397 // If the heap supports thread-local allocation buffers, it should override
398 // the following methods:
399 // Returns "true" iff the heap supports thread-local allocation buffers.
400 // The default is "no".
401 virtual bool supports_tlab_allocation() const = 0;
402
403 // The amount of space available for thread-local allocation buffers.
404 virtual size_t tlab_capacity(Thread *thr) const = 0;
405
406 // The amount of used space for thread-local allocation buffers for the given thread.
407 virtual size_t tlab_used(Thread *thr) const = 0;
408
409 virtual size_t max_tlab_size() const;
410
411 // An estimate of the maximum allocation that could be performed
412 // for thread-local allocation buffers without triggering any
413 // collection or expansion activity.
414 virtual size_t unsafe_max_tlab_alloc(Thread *thr) const {
415 guarantee(false, "thread-local allocation buffers not supported");
416 return 0;
417 }
418
419 // Perform a collection of the heap; intended for use in implementing
420 // "System.gc". This probably implies as full a collection as the
421 // "CollectedHeap" supports.
422 virtual void collect(GCCause::Cause cause) = 0;
423
424 // Perform a full collection
425 virtual void do_full_collection(bool clear_all_soft_refs) = 0;
426
427 // This interface assumes that it's being called by the
428 // vm thread. It collects the heap assuming that the
429 // heap lock is already held and that we are executing in
430 // the context of the vm thread.
431 virtual void collect_as_vm_thread(GCCause::Cause cause);
432
433 virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
434 size_t size,
435 Metaspace::MetadataType mdtype);
436
437 // Returns "true" iff there is a stop-world GC in progress. (I assume
438 // that it should answer "false" for the concurrent part of a concurrent
439 // collector -- dld).
440 bool is_gc_active() const { return _is_gc_active; }
441
442 // Total number of GC collections (started)
443 unsigned int total_collections() const { return _total_collections; }
444 unsigned int total_full_collections() const { return _total_full_collections;}
445
446 // Increment total number of GC collections (started)
447 // Should be protected but used by PSMarkSweep - cleanup for 1.4.2
448 void increment_total_collections(bool full = false) {
449 _total_collections++;
450 if (full) {
451 increment_total_full_collections();
452 }
453 }
454
455 void increment_total_full_collections() { _total_full_collections++; }
456
457 // Return the CollectorPolicy for the heap
458 virtual CollectorPolicy* collector_policy() const = 0;
459
460 // Return the SoftRefPolicy for the heap;
461 virtual SoftRefPolicy* soft_ref_policy() = 0;
462
463 virtual GrowableArray<GCMemoryManager*> memory_managers() = 0;
464 virtual GrowableArray<MemoryPool*> memory_pools() = 0;
465
466 // Iterate over all objects, calling "cl.do_object" on each.
467 virtual void object_iterate(ObjectClosure* cl) = 0;
468
469 // Similar to object_iterate() except iterates only
470 // over live objects.
471 virtual void safe_object_iterate(ObjectClosure* cl) = 0;
472
473 // NOTE! There is no requirement that a collector implement these
474 // functions.
475 //
476 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
477 // each address in the (reserved) heap is a member of exactly
478 // one block. The defining characteristic of a block is that it is
479 // possible to find its size, and thus to progress forward to the next
480 // block. (Blocks may be of different sizes.) Thus, blocks may
481 // represent Java objects, or they might be free blocks in a
482 // free-list-based heap (or subheap), as long as the two kinds are
483 // distinguishable and the size of each is determinable.
484
485 // Returns the address of the start of the "block" that contains the
486 // address "addr". We say "blocks" instead of "object" since some heaps
487 // may not pack objects densely; a chunk may either be an object or a
488 // non-object.
489 virtual HeapWord* block_start(const void* addr) const = 0;
490
491 // Requires "addr" to be the start of a chunk, and returns its size.
492 // "addr + size" is required to be the start of a new chunk, or the end
493 // of the active area of the heap.
494 virtual size_t block_size(const HeapWord* addr) const = 0;
495
496 // Requires "addr" to be the start of a block, and returns "TRUE" iff
497 // the block is an object.
498 virtual bool block_is_obj(const HeapWord* addr) const = 0;
499
500 // Returns the longest time (in ms) that has elapsed since the last
501 // time that any part of the heap was examined by a garbage collection.
502 virtual jlong millis_since_last_gc() = 0;
503
504 // Perform any cleanup actions necessary before allowing a verification.
505 virtual void prepare_for_verify() = 0;
506
507 // Generate any dumps preceding or following a full gc
508 private:
509 void full_gc_dump(GCTimer* timer, bool before);
510
511 virtual void initialize_serviceability() = 0;
512
513 public:
514 void pre_full_gc_dump(GCTimer* timer);
515 void post_full_gc_dump(GCTimer* timer);
516
517 virtual VirtualSpaceSummary create_heap_space_summary();
518 GCHeapSummary create_heap_summary();
519
520 MetaspaceSummary create_metaspace_summary();
521
522 // Print heap information on the given outputStream.
523 virtual void print_on(outputStream* st) const = 0;
524 // The default behavior is to call print_on() on tty.
525 virtual void print() const {
526 print_on(tty);
527 }
528 // Print more detailed heap information on the given
529 // outputStream. The default behavior is to call print_on(). It is
530 // up to each subclass to override it and add any additional output
531 // it needs.
532 virtual void print_extended_on(outputStream* st) const {
533 print_on(st);
534 }
535
536 virtual void print_on_error(outputStream* st) const;
537
538 // Print all GC threads (other than the VM thread)
539 // used by this heap.
540 virtual void print_gc_threads_on(outputStream* st) const = 0;
541 // The default behavior is to call print_gc_threads_on() on tty.
542 void print_gc_threads() {
543 print_gc_threads_on(tty);
544 }
545 // Iterator for all GC threads (other than VM thread)
546 virtual void gc_threads_do(ThreadClosure* tc) const = 0;
547
548 // Print any relevant tracing info that flags imply.
549 // Default implementation does nothing.
550 virtual void print_tracing_info() const = 0;
551
552 void print_heap_before_gc();
553 void print_heap_after_gc();
554
555 // An object is scavengable if its location may move during a scavenge.
556 // (A scavenge is a GC which is not a full GC.)
557 virtual bool is_scavengable(oop obj) = 0;
558 // Registering and unregistering an nmethod (compiled code) with the heap.
559 // Override with specific mechanism for each specialized heap type.
560 virtual void register_nmethod(nmethod* nm) {}
561 virtual void unregister_nmethod(nmethod* nm) {}
562 virtual void verify_nmethod(nmethod* nmethod) {}
563
564 void trace_heap_before_gc(const GCTracer* gc_tracer);
565 void trace_heap_after_gc(const GCTracer* gc_tracer);
566
567 // Heap verification
568 virtual void verify(VerifyOption option) = 0;
569
570 // Return true if concurrent phase control (via
571 // request_concurrent_phase_control) is supported by this collector.
572 // The default implementation returns false.
573 virtual bool supports_concurrent_phase_control() const;
574
575 // Return a NULL terminated array of concurrent phase names provided
576 // by this collector. Supports Whitebox testing. These are the
577 // names recognized by request_concurrent_phase(). The default
578 // implementation returns an array of one NULL element.
579 virtual const char* const* concurrent_phases() const;
580
581 // Request the collector enter the indicated concurrent phase, and
582 // wait until it does so. Supports WhiteBox testing. Only one
583 // request may be active at a time. Phases are designated by name;
584 // the set of names and their meaning is GC-specific. Once the
585 // requested phase has been reached, the collector will attempt to
586 // avoid transitioning to a new phase until a new request is made.
587 // [Note: A collector might not be able to remain in a given phase.
588 // For example, a full collection might cancel an in-progress
589 // concurrent collection.]
590 //
591 // Returns true when the phase is reached. Returns false for an
592 // unknown phase. The default implementation returns false.
593 virtual bool request_concurrent_phase(const char* phase);
594
595 // Provides a thread pool to SafepointSynchronize to use
596 // for parallel safepoint cleanup.
597 // GCs that use a GC worker thread pool may want to share
598 // it for use during safepoint cleanup. This is only possible
599 // if the GC can pause and resume concurrent work (e.g. G1
600 // concurrent marking) for an intermittent non-GC safepoint.
601 // If this method returns NULL, SafepointSynchronize will
602 // perform cleanup tasks serially in the VMThread.
603 virtual WorkGang* get_safepoint_workers() { return NULL; }
604
605 // Support for object pinning. This is used by JNI Get*Critical()
606 // and Release*Critical() family of functions. If supported, the GC
607 // must guarantee that pinned objects never move.
608 virtual bool supports_object_pinning() const;
609 virtual oop pin_object(JavaThread* thread, oop obj);
610 virtual void unpin_object(JavaThread* thread, oop obj);
611
612 // Deduplicate the string, iff the GC supports string deduplication.
613 virtual void deduplicate_string(oop str);
614
615 virtual bool is_oop(oop object) const;
616
617 // Non product verification and debugging.
618 #ifndef PRODUCT
619 // Support for PromotionFailureALot. Return true if it's time to cause a
620 // promotion failure. The no-argument version uses
621 // this->_promotion_failure_alot_count as the counter.
622 bool promotion_should_fail(volatile size_t* count);
623 bool promotion_should_fail();
624
625 // Reset the PromotionFailureALot counters. Should be called at the end of a
626 // GC in which promotion failure occurred.
627 void reset_promotion_should_fail(volatile size_t* count);
628 void reset_promotion_should_fail();
629 #endif // #ifndef PRODUCT
630
631 #ifdef ASSERT
632 static int fired_fake_oom() {
633 return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt);
634 }
635 #endif
636 };
637
638 // Class to set and reset the GC cause for a CollectedHeap.
639
640 class GCCauseSetter : StackObj {
641 CollectedHeap* _heap;
642 GCCause::Cause _previous_cause;
643 public:
644 GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) {
645 _heap = heap;
646 _previous_cause = _heap->gc_cause();
647 _heap->set_gc_cause(cause);
648 }
649
650 ~GCCauseSetter() {
651 _heap->set_gc_cause(_previous_cause);
652 }
653 };
654
655 #endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP