1 /*
2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2013, 2021, Red Hat, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
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24 */
25
26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
27 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
28
29 #include "gc/shared/markBitMap.hpp"
30 #include "gc/shared/softRefPolicy.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp"
33 #include "gc/shenandoah/shenandoahAsserts.hpp"
34 #include "gc/shenandoah/shenandoahAllocRequest.hpp"
35 #include "gc/shenandoah/shenandoahLock.hpp"
36 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
37 #include "gc/shenandoah/shenandoahPadding.hpp"
38 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
39 #include "gc/shenandoah/shenandoahUnload.hpp"
40 #include "memory/metaspace.hpp"
41 #include "services/memoryManager.hpp"
42 #include "utilities/globalDefinitions.hpp"
43 #include "utilities/stack.hpp"
44
45 class ConcurrentGCTimer;
46 class ObjectIterateScanRootClosure;
47 class ShenandoahCollectorPolicy;
48 class ShenandoahControlThread;
49 class ShenandoahGCSession;
50 class ShenandoahGCStateResetter;
51 class ShenandoahHeuristics;
52 class ShenandoahMarkingContext;
53 class ShenandoahMode;
54 class ShenandoahPhaseTimings;
55 class ShenandoahHeap;
56 class ShenandoahHeapRegion;
57 class ShenandoahHeapRegionClosure;
58 class ShenandoahCollectionSet;
59 class ShenandoahFreeSet;
60 class ShenandoahConcurrentMark;
61 class ShenandoahFullGC;
62 class ShenandoahMonitoringSupport;
63 class ShenandoahPacer;
64 class ShenandoahReferenceProcessor;
65 class ShenandoahVerifier;
66 class ShenandoahWorkerThreads;
67 class VMStructs;
68
69 // Used for buffering per-region liveness data.
70 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
71 // The ShenandoahHeap array has max-workers elements, each of which is an array of
72 // uint16_t * max_regions. The choice of uint16_t is not accidental:
73 // there is a tradeoff between static/dynamic footprint that translates
74 // into cache pressure (which is already high during marking), and
75 // too many atomic updates. uint32_t is too large, uint8_t is too small.
76 typedef uint16_t ShenandoahLiveData;
77 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1)
78
79 class ShenandoahRegionIterator : public StackObj {
80 private:
81 ShenandoahHeap* _heap;
82
83 shenandoah_padding(0);
84 volatile size_t _index;
85 shenandoah_padding(1);
86
87 // No implicit copying: iterators should be passed by reference to capture the state
88 NONCOPYABLE(ShenandoahRegionIterator);
89
90 public:
91 ShenandoahRegionIterator();
92 ShenandoahRegionIterator(ShenandoahHeap* heap);
93
94 // Reset iterator to default state
95 void reset();
96
97 // Returns next region, or null if there are no more regions.
98 // This is multi-thread-safe.
99 inline ShenandoahHeapRegion* next();
100
101 // This is *not* MT safe. However, in the absence of multithreaded access, it
102 // can be used to determine if there is more work to do.
103 bool has_next() const;
104 };
105
106 class ShenandoahHeapRegionClosure : public StackObj {
107 public:
108 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
109 virtual bool is_thread_safe() { return false; }
110 };
111
112 typedef ShenandoahLock ShenandoahHeapLock;
113 typedef ShenandoahLocker ShenandoahHeapLocker;
114 typedef Stack<oop, mtGC> ShenandoahScanObjectStack;
115
116 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
117 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
118 // See ShenandoahControlThread for GC cycle structure.
119 //
120 class ShenandoahHeap : public CollectedHeap, public ShenandoahSpaceInfo {
121 friend class ShenandoahAsserts;
122 friend class VMStructs;
123 friend class ShenandoahGCSession;
124 friend class ShenandoahGCStateResetter;
125 friend class ShenandoahParallelObjectIterator;
126 friend class ShenandoahSafepoint;
127 // Supported GC
128 friend class ShenandoahConcurrentGC;
129 friend class ShenandoahDegenGC;
130 friend class ShenandoahFullGC;
131 friend class ShenandoahUnload;
132
133 // ---------- Locks that guard important data structures in Heap
134 //
135 private:
136 ShenandoahHeapLock _lock;
137
138 public:
139 ShenandoahHeapLock* lock() {
140 return &_lock;
141 }
142
143 // ---------- Initialization, termination, identification, printing routines
144 //
145 public:
146 static ShenandoahHeap* heap();
147
148 const char* name() const override { return "Shenandoah"; }
149 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; }
150
151 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
152 jint initialize() override;
153 void post_initialize() override;
154 void initialize_mode();
155 void initialize_heuristics();
156
157 void initialize_serviceability() override;
158
159 void print_on(outputStream* st) const override;
160 void print_extended_on(outputStream *st) const override;
161 void print_tracing_info() const override;
162 void print_heap_regions_on(outputStream* st) const;
163
164 void stop() override;
165
166 void prepare_for_verify() override;
167 void verify(VerifyOption vo) override;
168
169 // WhiteBox testing support.
170 bool supports_concurrent_gc_breakpoints() const override {
171 return true;
172 }
173
174 // ---------- Heap counters and metrics
175 //
176 private:
177 size_t _initial_size;
178 size_t _minimum_size;
179 volatile size_t _soft_max_size;
180 shenandoah_padding(0);
181 volatile size_t _used;
182 volatile size_t _committed;
183 volatile size_t _bytes_allocated_since_gc_start;
184 shenandoah_padding(1);
185
186 public:
187 void increase_used(size_t bytes);
188 void decrease_used(size_t bytes);
189 void set_used(size_t bytes);
190
191 void increase_committed(size_t bytes);
192 void decrease_committed(size_t bytes);
193 void increase_allocated(size_t bytes);
194
195 size_t bytes_allocated_since_gc_start() const override;
196 void reset_bytes_allocated_since_gc_start();
197
198 size_t min_capacity() const;
199 size_t max_capacity() const override;
200 size_t soft_max_capacity() const override;
201 size_t initial_capacity() const;
202 size_t capacity() const override;
203 size_t used() const override;
204 size_t committed() const;
205 size_t available() const override;
206
207 void set_soft_max_capacity(size_t v);
208
209 // ---------- Workers handling
210 //
211 private:
212 uint _max_workers;
213 ShenandoahWorkerThreads* _workers;
214 ShenandoahWorkerThreads* _safepoint_workers;
215
216 public:
217 uint max_workers();
218 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
219
220 WorkerThreads* workers() const;
221 WorkerThreads* safepoint_workers() override;
222
223 void gc_threads_do(ThreadClosure* tcl) const override;
224
225 // ---------- Heap regions handling machinery
226 //
227 private:
228 MemRegion _heap_region;
229 bool _heap_region_special;
230 size_t _num_regions;
231 ShenandoahHeapRegion** _regions;
232 ShenandoahRegionIterator _update_refs_iterator;
233
234 public:
235
236 inline HeapWord* base() const { return _heap_region.start(); }
237
238 inline size_t num_regions() const { return _num_regions; }
239 inline bool is_heap_region_special() { return _heap_region_special; }
240
241 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const;
242 inline size_t heap_region_index_containing(const void* addr) const;
243
244 inline ShenandoahHeapRegion* get_region(size_t region_idx) const;
245
246 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
247 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
248
249 // ---------- GC state machinery
250 //
251 // GC state describes the important parts of collector state, that may be
252 // used to make barrier selection decisions in the native and generated code.
253 // Multiple bits can be set at once.
254 //
255 // Important invariant: when GC state is zero, the heap is stable, and no barriers
256 // are required.
257 //
258 public:
259 enum GCStateBitPos {
260 // Heap has forwarded objects: needs LRB barriers.
261 HAS_FORWARDED_BITPOS = 0,
262
263 // Heap is under marking: needs SATB barriers.
264 MARKING_BITPOS = 1,
265
266 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
267 EVACUATION_BITPOS = 2,
268
269 // Heap is under updating: needs no additional barriers.
270 UPDATEREFS_BITPOS = 3,
271
272 // Heap is under weak-reference/roots processing: needs weak-LRB barriers.
273 WEAK_ROOTS_BITPOS = 4,
274 };
275
276 enum GCState {
277 STABLE = 0,
278 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
279 MARKING = 1 << MARKING_BITPOS,
280 EVACUATION = 1 << EVACUATION_BITPOS,
281 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
282 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS,
283 };
284
285 private:
286 ShenandoahSharedBitmap _gc_state;
287 ShenandoahSharedFlag _degenerated_gc_in_progress;
288 ShenandoahSharedFlag _full_gc_in_progress;
289 ShenandoahSharedFlag _full_gc_move_in_progress;
290 ShenandoahSharedFlag _progress_last_gc;
291 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
292
293 void set_gc_state_all_threads(char state);
294 void set_gc_state_mask(uint mask, bool value);
295
296 public:
297 char gc_state() const;
298 static address gc_state_addr();
299
300 void set_concurrent_mark_in_progress(bool in_progress);
301 void set_evacuation_in_progress(bool in_progress);
302 void set_update_refs_in_progress(bool in_progress);
303 void set_degenerated_gc_in_progress(bool in_progress);
304 void set_full_gc_in_progress(bool in_progress);
305 void set_full_gc_move_in_progress(bool in_progress);
306 void set_has_forwarded_objects(bool cond);
307 void set_concurrent_strong_root_in_progress(bool cond);
308 void set_concurrent_weak_root_in_progress(bool cond);
309
310 inline bool is_stable() const;
311 inline bool is_idle() const;
312 inline bool is_concurrent_mark_in_progress() const;
313 inline bool is_update_refs_in_progress() const;
314 inline bool is_evacuation_in_progress() const;
315 inline bool is_degenerated_gc_in_progress() const;
316 inline bool is_full_gc_in_progress() const;
317 inline bool is_full_gc_move_in_progress() const;
318 inline bool has_forwarded_objects() const;
319 inline bool is_gc_in_progress_mask(uint mask) const;
320 inline bool is_stw_gc_in_progress() const;
321 inline bool is_concurrent_strong_root_in_progress() const;
322 inline bool is_concurrent_weak_root_in_progress() const;
323
324 private:
325 enum CancelState {
326 // Normal state. GC has not been cancelled and is open for cancellation.
327 // Worker threads can suspend for safepoint.
328 CANCELLABLE,
329
330 // GC has been cancelled. Worker threads can not suspend for
331 // safepoint but must finish their work as soon as possible.
332 CANCELLED
333 };
334
335 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
336 bool try_cancel_gc();
337
338 public:
339 static address cancelled_gc_addr();
340
341 inline bool cancelled_gc() const;
342 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
343
344 inline void clear_cancelled_gc();
345
346 void cancel_gc(GCCause::Cause cause);
347
348 public:
349 // Elastic heap support
350 void entry_uncommit(double shrink_before, size_t shrink_until);
351 void op_uncommit(double shrink_before, size_t shrink_until);
352
353 private:
354 // GC support
355 // Reset bitmap, prepare regions for new GC cycle
356 void prepare_gc();
357 void prepare_regions_and_collection_set(bool concurrent);
358 // Evacuation
359 void prepare_evacuation(bool concurrent);
360 void evacuate_collection_set(bool concurrent);
361 // Concurrent root processing
362 void prepare_concurrent_roots();
363 void finish_concurrent_roots();
364 // Concurrent class unloading support
365 void do_class_unloading();
366 // Reference updating
367 void prepare_update_heap_references(bool concurrent);
368 void update_heap_references(bool concurrent);
369 // Final update region states
370 void update_heap_region_states(bool concurrent);
371 void rebuild_free_set(bool concurrent);
372
373 void rendezvous_threads();
374 void recycle_trash();
375 public:
376 void notify_gc_progress() { _progress_last_gc.set(); }
377 void notify_gc_no_progress() { _progress_last_gc.unset(); }
378
379 //
380 // Mark support
381 private:
382 ShenandoahControlThread* _control_thread;
383 ShenandoahCollectorPolicy* _shenandoah_policy;
384 ShenandoahMode* _gc_mode;
385 ShenandoahHeuristics* _heuristics;
386 ShenandoahFreeSet* _free_set;
387 ShenandoahPacer* _pacer;
388 ShenandoahVerifier* _verifier;
389
390 ShenandoahPhaseTimings* _phase_timings;
391
392 ShenandoahControlThread* control_thread() { return _control_thread; }
393
394 public:
395 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
396 ShenandoahMode* mode() const { return _gc_mode; }
397 ShenandoahHeuristics* heuristics() const { return _heuristics; }
398 ShenandoahFreeSet* free_set() const { return _free_set; }
399 ShenandoahPacer* pacer() const { return _pacer; }
400
401 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
402
403 ShenandoahVerifier* verifier();
404
405 // ---------- VM subsystem bindings
406 //
407 private:
408 ShenandoahMonitoringSupport* _monitoring_support;
409 MemoryPool* _memory_pool;
410 GCMemoryManager _stw_memory_manager;
411 GCMemoryManager _cycle_memory_manager;
412 ConcurrentGCTimer* _gc_timer;
413 SoftRefPolicy _soft_ref_policy;
414
415 // For exporting to SA
416 int _log_min_obj_alignment_in_bytes;
417 public:
418 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
419 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
420 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
421 SoftRefPolicy* soft_ref_policy() override { return &_soft_ref_policy; }
422
423 GrowableArray<GCMemoryManager*> memory_managers() override;
424 GrowableArray<MemoryPool*> memory_pools() override;
425 MemoryUsage memory_usage() override;
426 GCTracer* tracer();
427 ConcurrentGCTimer* gc_timer() const;
428
429 // ---------- Reference processing
430 //
431 private:
432 ShenandoahReferenceProcessor* const _ref_processor;
433
434 public:
435 ShenandoahReferenceProcessor* ref_processor() { return _ref_processor; }
436
437 // ---------- Class Unloading
438 //
439 private:
440 ShenandoahSharedFlag _unload_classes;
441 ShenandoahUnload _unloader;
442
443 public:
444 void set_unload_classes(bool uc);
445 bool unload_classes() const;
446
447 // Perform STW class unloading and weak root cleaning
448 void parallel_cleaning(bool full_gc);
449
450 private:
451 void stw_unload_classes(bool full_gc);
452 void stw_process_weak_roots(bool full_gc);
453 void stw_weak_refs(bool full_gc);
454
455 // Heap iteration support
456 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops);
457 bool prepare_aux_bitmap_for_iteration();
458 void reclaim_aux_bitmap_for_iteration();
459
460 // ---------- Generic interface hooks
461 // Minor things that super-interface expects us to implement to play nice with
462 // the rest of runtime. Some of the things here are not required to be implemented,
463 // and can be stubbed out.
464 //
465 public:
466 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false);
467
468 bool is_in(const void* p) const override;
469
470 bool requires_barriers(stackChunkOop obj) const override;
471
472 MemRegion reserved_region() const { return _reserved; }
473 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
474
475 void collect(GCCause::Cause cause) override;
476 void do_full_collection(bool clear_all_soft_refs) override;
477
478 // Used for parsing heap during error printing
479 HeapWord* block_start(const void* addr) const;
480 bool block_is_obj(const HeapWord* addr) const;
481 bool print_location(outputStream* st, void* addr) const override;
482
483 // Used for native heap walkers: heap dumpers, mostly
484 void object_iterate(ObjectClosure* cl) override;
485 // Parallel heap iteration support
486 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override;
487
488 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
489 void keep_alive(oop obj) override;
490
491 // ---------- Safepoint interface hooks
492 //
493 public:
494 void safepoint_synchronize_begin() override;
495 void safepoint_synchronize_end() override;
496
497 // ---------- Code roots handling hooks
498 //
499 public:
500 void register_nmethod(nmethod* nm) override;
501 void unregister_nmethod(nmethod* nm) override;
502 void verify_nmethod(nmethod* nm) override {}
503
504 // ---------- Pinning hooks
505 //
506 public:
507 // Shenandoah supports per-object (per-region) pinning
508 void pin_object(JavaThread* thread, oop obj) override;
509 void unpin_object(JavaThread* thread, oop obj) override;
510
511 void sync_pinned_region_status();
512 void assert_pinned_region_status() NOT_DEBUG_RETURN;
513
514 // ---------- Concurrent Stack Processing support
515 //
516 public:
517 bool uses_stack_watermark_barrier() const override { return true; }
518
519 // ---------- Allocation support
520 //
521 private:
522 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
523 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
524 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
525 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
526
527 public:
528 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
529 HeapWord* mem_allocate(size_t size, bool* what) override;
530 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
531 size_t size,
532 Metaspace::MetadataType mdtype) override;
533
534 void notify_mutator_alloc_words(size_t words, bool waste);
535
536 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override;
537 size_t tlab_capacity(Thread *thr) const override;
538 size_t unsafe_max_tlab_alloc(Thread *thread) const override;
539 size_t max_tlab_size() const override;
540 size_t tlab_used(Thread* ignored) const override;
541
542 void ensure_parsability(bool retire_labs) override;
543
544 void labs_make_parsable();
545 void tlabs_retire(bool resize);
546 void gclabs_retire(bool resize);
547
548 // ---------- Marking support
549 //
550 private:
551 ShenandoahMarkingContext* _marking_context;
552 MemRegion _bitmap_region;
553 MemRegion _aux_bitmap_region;
554 MarkBitMap _verification_bit_map;
555 MarkBitMap _aux_bit_map;
556
557 size_t _bitmap_size;
558 size_t _bitmap_regions_per_slice;
559 size_t _bitmap_bytes_per_slice;
560
561 size_t _pretouch_heap_page_size;
562 size_t _pretouch_bitmap_page_size;
563
564 bool _bitmap_region_special;
565 bool _aux_bitmap_region_special;
566
567 ShenandoahLiveData** _liveness_cache;
568
569 public:
570 inline ShenandoahMarkingContext* complete_marking_context() const;
571 inline ShenandoahMarkingContext* marking_context() const;
572 inline void mark_complete_marking_context();
573 inline void mark_incomplete_marking_context();
574
575 template<class T>
576 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
577
578 template<class T>
579 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
580
581 template<class T>
582 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
583
584 void reset_mark_bitmap();
585
586 // SATB barriers hooks
587 inline bool requires_marking(const void* entry) const;
588
589 // Support for bitmap uncommits
590 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
591 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
592 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
593
594 // Liveness caching support
595 ShenandoahLiveData* get_liveness_cache(uint worker_id);
596 void flush_liveness_cache(uint worker_id);
597
598 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
599
600 // ---------- Evacuation support
601 //
602 private:
603 ShenandoahCollectionSet* _collection_set;
604 ShenandoahEvacOOMHandler _oom_evac_handler;
605
606 public:
607 static address in_cset_fast_test_addr();
608
609 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
610
611 // Checks if object is in the collection set.
612 inline bool in_collection_set(oop obj) const;
613
614 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
615 inline bool in_collection_set_loc(void* loc) const;
616
617 // Evacuates object src. Returns the evacuated object, either evacuated
618 // by this thread, or by some other thread.
619 inline oop evacuate_object(oop src, Thread* thread);
620
621 // Call before/after evacuation.
622 inline void enter_evacuation(Thread* t);
623 inline void leave_evacuation(Thread* t);
624
625 // ---------- Helper functions
626 //
627 public:
628 template <class T>
629 inline void conc_update_with_forwarded(T* p);
630
631 template <class T>
632 inline void update_with_forwarded(T* p);
633
634 static inline void atomic_update_oop(oop update, oop* addr, oop compare);
635 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare);
636 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare);
637
638 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare);
639 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare);
640 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare);
641
642 static inline void atomic_clear_oop( oop* addr, oop compare);
643 static inline void atomic_clear_oop(narrowOop* addr, oop compare);
644 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare);
645
646 void trash_humongous_region_at(ShenandoahHeapRegion *r);
647
648 private:
649 void trash_cset_regions();
650
651 // ---------- Testing helpers functions
652 //
653 private:
654 ShenandoahSharedFlag _inject_alloc_failure;
655
656 void try_inject_alloc_failure();
657 bool should_inject_alloc_failure();
658 };
659
660 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP