1 /*
2 * Copyright (c) 2023, 2024, 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
128 // Supported GC
129 friend class ShenandoahConcurrentGC;
130 friend class ShenandoahDegenGC;
131 friend class ShenandoahFullGC;
132 friend class ShenandoahUnload;
133
134 // ---------- Locks that guard important data structures in Heap
135 //
136 private:
137 ShenandoahHeapLock _lock;
138
139 public:
140 ShenandoahHeapLock* lock() {
141 return &_lock;
142 }
143
144 // ---------- Initialization, termination, identification, printing routines
145 //
146 public:
147 static ShenandoahHeap* heap();
148
149 const char* name() const override { return "Shenandoah"; }
150 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; }
151
152 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
153 jint initialize() override;
154 void post_initialize() override;
155 void initialize_mode();
156 void initialize_heuristics();
157
158 void initialize_serviceability() override;
159
160 void print_on(outputStream* st) const override;
161 void print_extended_on(outputStream *st) const override;
162 void print_tracing_info() const override;
163 void print_heap_regions_on(outputStream* st) const;
164
165 void stop() override;
166
167 void prepare_for_verify() override;
168 void verify(VerifyOption vo) override;
169
170 // WhiteBox testing support.
171 bool supports_concurrent_gc_breakpoints() const override {
172 return true;
173 }
174
175 // ---------- Heap counters and metrics
176 //
177 private:
178 size_t _initial_size;
179 size_t _minimum_size;
180 volatile size_t _soft_max_size;
181 shenandoah_padding(0);
182 volatile size_t _used;
183 volatile size_t _committed;
184 volatile size_t _bytes_allocated_since_gc_start;
185 shenandoah_padding(1);
186
187 public:
188 void increase_used(size_t bytes);
189 void decrease_used(size_t bytes);
190 void set_used(size_t bytes);
191
192 void increase_committed(size_t bytes);
193 void decrease_committed(size_t bytes);
194 void increase_allocated(size_t bytes);
195
196 size_t bytes_allocated_since_gc_start() const override;
197 void reset_bytes_allocated_since_gc_start();
198
199 size_t min_capacity() const;
200 size_t max_capacity() const override;
201 size_t soft_max_capacity() const override;
202 size_t initial_capacity() const;
203 size_t capacity() const override;
204 size_t used() const override;
205 size_t committed() const;
206 size_t available() const override;
207
208 void set_soft_max_capacity(size_t v);
209
210 // ---------- Periodic Tasks
211 //
212 private:
213 void notify_heap_changed();
214
215 public:
216 void set_forced_counters_update(bool value);
217 void handle_force_counters_update();
218
219 // ---------- Workers handling
220 //
221 private:
222 uint _max_workers;
223 ShenandoahWorkerThreads* _workers;
224 ShenandoahWorkerThreads* _safepoint_workers;
225
226 public:
227 uint max_workers();
228 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
229
230 WorkerThreads* workers() const;
231 WorkerThreads* safepoint_workers() override;
232
233 void gc_threads_do(ThreadClosure* tcl) const override;
234
235 // ---------- Heap regions handling machinery
236 //
237 private:
238 MemRegion _heap_region;
239 bool _heap_region_special;
240 size_t _num_regions;
241 ShenandoahHeapRegion** _regions;
242 ShenandoahRegionIterator _update_refs_iterator;
243
244 public:
245
246 inline HeapWord* base() const { return _heap_region.start(); }
247
248 inline size_t num_regions() const { return _num_regions; }
249 inline bool is_heap_region_special() { return _heap_region_special; }
250
251 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const;
252 inline size_t heap_region_index_containing(const void* addr) const;
253
254 inline ShenandoahHeapRegion* get_region(size_t region_idx) const;
255
256 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
257 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
258
259 // ---------- GC state machinery
260 //
261 // GC state describes the important parts of collector state, that may be
262 // used to make barrier selection decisions in the native and generated code.
263 // Multiple bits can be set at once.
264 //
265 // Important invariant: when GC state is zero, the heap is stable, and no barriers
266 // are required.
267 //
268 public:
269 enum GCStateBitPos {
270 // Heap has forwarded objects: needs LRB barriers.
271 HAS_FORWARDED_BITPOS = 0,
272
273 // Heap is under marking: needs SATB barriers.
274 MARKING_BITPOS = 1,
275
276 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
277 EVACUATION_BITPOS = 2,
278
279 // Heap is under updating: needs no additional barriers.
280 UPDATEREFS_BITPOS = 3,
281
282 // Heap is under weak-reference/roots processing: needs weak-LRB barriers.
283 WEAK_ROOTS_BITPOS = 4,
284 };
285
286 enum GCState {
287 STABLE = 0,
288 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
289 MARKING = 1 << MARKING_BITPOS,
290 EVACUATION = 1 << EVACUATION_BITPOS,
291 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
292 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS,
293 };
294
295 private:
296 bool _gc_state_changed;
297 ShenandoahSharedBitmap _gc_state;
298
299 // tracks if new regions have been allocated or retired since last check
300 ShenandoahSharedFlag _heap_changed;
301 ShenandoahSharedFlag _degenerated_gc_in_progress;
302 ShenandoahSharedFlag _full_gc_in_progress;
303 ShenandoahSharedFlag _full_gc_move_in_progress;
304 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
305
306 size_t _gc_no_progress_count;
307
308 // This updates the singlular, global gc state. This must happen on a safepoint.
309 void set_gc_state(uint mask, bool value);
310
311 public:
312 char gc_state() const;
313
314 // This copies the global gc state into a thread local variable for java threads.
315 // It is primarily intended to support quick access at barriers.
316 void propagate_gc_state_to_java_threads();
317
318 // This is public to support assertions that the state hasn't been changed off of
319 // a safepoint and that any changes were propagated to java threads after the safepoint.
320 bool has_gc_state_changed() const { return _gc_state_changed; }
321
322 // Returns true if allocations have occurred in new regions or if regions have been
323 // uncommitted since the previous calls. This call will reset the flag to false.
324 bool has_changed() {
325 return _heap_changed.try_unset();
326 }
327
328 void set_concurrent_mark_in_progress(bool in_progress);
329 void set_evacuation_in_progress(bool in_progress);
330 void set_update_refs_in_progress(bool in_progress);
331 void set_degenerated_gc_in_progress(bool in_progress);
332 void set_full_gc_in_progress(bool in_progress);
333 void set_full_gc_move_in_progress(bool in_progress);
334 void set_has_forwarded_objects(bool cond);
335 void set_concurrent_strong_root_in_progress(bool cond);
336 void set_concurrent_weak_root_in_progress(bool cond);
337
338 inline bool is_stable() const;
339 inline bool is_idle() const;
340 inline bool is_concurrent_mark_in_progress() const;
341 inline bool is_update_refs_in_progress() const;
342 inline bool is_evacuation_in_progress() const;
343 inline bool is_degenerated_gc_in_progress() const;
344 inline bool is_full_gc_in_progress() const;
345 inline bool is_full_gc_move_in_progress() const;
346 inline bool has_forwarded_objects() const;
347
348 inline bool is_stw_gc_in_progress() const;
349 inline bool is_concurrent_strong_root_in_progress() const;
350 inline bool is_concurrent_weak_root_in_progress() const;
351
352 private:
353 enum CancelState {
354 // Normal state. GC has not been cancelled and is open for cancellation.
355 // Worker threads can suspend for safepoint.
356 CANCELLABLE,
357
358 // GC has been cancelled. Worker threads can not suspend for
359 // safepoint but must finish their work as soon as possible.
360 CANCELLED
361 };
362
363 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
364 bool try_cancel_gc();
365
366 public:
367
368 inline bool cancelled_gc() const;
369 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
370
371 inline void clear_cancelled_gc();
372
373 void cancel_gc(GCCause::Cause cause);
374
375 public:
376 // These will uncommit empty regions if heap::committed > shrink_until
377 // and there exists at least one region which was made empty before shrink_before.
378 void maybe_uncommit(double shrink_before, size_t shrink_until);
379 void op_uncommit(double shrink_before, size_t shrink_until);
380
381 // Returns true if the soft maximum heap has been changed using management APIs.
382 bool check_soft_max_changed();
383
384 private:
385 // GC support
386 // Reset bitmap, prepare regions for new GC cycle
387 void prepare_gc();
388 void prepare_regions_and_collection_set(bool concurrent);
389 // Evacuation
390 void evacuate_collection_set(bool concurrent);
391 // Concurrent root processing
392 void prepare_concurrent_roots();
393 void finish_concurrent_roots();
394 // Concurrent class unloading support
395 void do_class_unloading();
396 // Reference updating
397 void prepare_update_heap_references(bool concurrent);
398 void update_heap_references(bool concurrent);
399 // Final update region states
400 void update_heap_region_states(bool concurrent);
401 void rebuild_free_set(bool concurrent);
402
403 void rendezvous_threads(const char* name);
404 void recycle_trash();
405 public:
406 void notify_gc_progress();
407 void notify_gc_no_progress();
408 size_t get_gc_no_progress_count() const;
409
410 //
411 // Mark support
412 private:
413 ShenandoahControlThread* _control_thread;
414 ShenandoahCollectorPolicy* _shenandoah_policy;
415 ShenandoahMode* _gc_mode;
416 ShenandoahHeuristics* _heuristics;
417 ShenandoahFreeSet* _free_set;
418 ShenandoahPacer* _pacer;
419 ShenandoahVerifier* _verifier;
420
421 ShenandoahPhaseTimings* _phase_timings;
422
423 ShenandoahControlThread* control_thread() { return _control_thread; }
424
425 public:
426 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
427 ShenandoahMode* mode() const { return _gc_mode; }
428 ShenandoahHeuristics* heuristics() const { return _heuristics; }
429 ShenandoahFreeSet* free_set() const { return _free_set; }
430 ShenandoahPacer* pacer() const { return _pacer; }
431
432 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
433
434 ShenandoahVerifier* verifier();
435
436 // ---------- VM subsystem bindings
437 //
438 private:
439 ShenandoahMonitoringSupport* _monitoring_support;
440 MemoryPool* _memory_pool;
441 GCMemoryManager _stw_memory_manager;
442 GCMemoryManager _cycle_memory_manager;
443 ConcurrentGCTimer* _gc_timer;
444 // For exporting to SA
445 int _log_min_obj_alignment_in_bytes;
446 public:
447 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
448 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
449 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
450
451 GrowableArray<GCMemoryManager*> memory_managers() override;
452 GrowableArray<MemoryPool*> memory_pools() override;
453 MemoryUsage memory_usage() override;
454 GCTracer* tracer();
455 ConcurrentGCTimer* gc_timer() const;
456
457 // ---------- Reference processing
458 //
459 private:
460 ShenandoahReferenceProcessor* const _ref_processor;
461
462 public:
463 ShenandoahReferenceProcessor* ref_processor() { return _ref_processor; }
464
465 // ---------- Class Unloading
466 //
467 private:
468 ShenandoahSharedFlag _unload_classes;
469 ShenandoahUnload _unloader;
470
471 public:
472 void set_unload_classes(bool uc);
473 bool unload_classes() const;
474
475 // Perform STW class unloading and weak root cleaning
476 void parallel_cleaning(bool full_gc);
477
478 private:
479 void stw_unload_classes(bool full_gc);
480 void stw_process_weak_roots(bool full_gc);
481 void stw_weak_refs(bool full_gc);
482
483 // Heap iteration support
484 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops);
485 bool prepare_aux_bitmap_for_iteration();
486 void reclaim_aux_bitmap_for_iteration();
487
488 // ---------- Generic interface hooks
489 // Minor things that super-interface expects us to implement to play nice with
490 // the rest of runtime. Some of the things here are not required to be implemented,
491 // and can be stubbed out.
492 //
493 public:
494 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false);
495
496 // Check the pointer is in active part of Java heap.
497 // Use is_in_reserved to check if object is within heap bounds.
498 bool is_in(const void* p) const override;
499
500 bool requires_barriers(stackChunkOop obj) const override;
501
502 MemRegion reserved_region() const { return _reserved; }
503 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
504
505 void collect(GCCause::Cause cause) override;
506 void do_full_collection(bool clear_all_soft_refs) override;
507
508 // Used for parsing heap during error printing
509 HeapWord* block_start(const void* addr) const;
510 bool block_is_obj(const HeapWord* addr) const;
511 bool print_location(outputStream* st, void* addr) const override;
512
513 // Used for native heap walkers: heap dumpers, mostly
514 void object_iterate(ObjectClosure* cl) override;
515 // Parallel heap iteration support
516 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override;
517
518 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
519 void keep_alive(oop obj) override;
520
521 // ---------- Safepoint interface hooks
522 //
523 public:
524 void safepoint_synchronize_begin() override;
525 void safepoint_synchronize_end() override;
526
527 // ---------- Code roots handling hooks
528 //
529 public:
530 void register_nmethod(nmethod* nm) override;
531 void unregister_nmethod(nmethod* nm) override;
532 void verify_nmethod(nmethod* nm) override {}
533
534 // ---------- Pinning hooks
535 //
536 public:
537 // Shenandoah supports per-object (per-region) pinning
538 void pin_object(JavaThread* thread, oop obj) override;
539 void unpin_object(JavaThread* thread, oop obj) override;
540
541 void sync_pinned_region_status();
542 void assert_pinned_region_status() NOT_DEBUG_RETURN;
543
544 // ---------- CDS archive support
545
546 bool can_load_archived_objects() const override { return true; }
547 HeapWord* allocate_loaded_archive_space(size_t size) override;
548 void complete_loaded_archive_space(MemRegion archive_space) override;
549
550 // ---------- Allocation support
551 //
552 private:
553 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
554 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
555 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
556 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
557
558 public:
559 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
560 HeapWord* mem_allocate(size_t size, bool* what) override;
561 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
562 size_t size,
563 Metaspace::MetadataType mdtype) override;
564
565 void notify_mutator_alloc_words(size_t words, bool waste);
566
567 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override;
568 size_t tlab_capacity(Thread *thr) const override;
569 size_t unsafe_max_tlab_alloc(Thread *thread) const override;
570 size_t max_tlab_size() const override;
571 size_t tlab_used(Thread* ignored) const override;
572
573 void ensure_parsability(bool retire_labs) override;
574
575 void labs_make_parsable();
576 void tlabs_retire(bool resize);
577 void gclabs_retire(bool resize);
578
579 // ---------- Marking support
580 //
581 private:
582 ShenandoahMarkingContext* _marking_context;
583 MemRegion _bitmap_region;
584 MemRegion _aux_bitmap_region;
585 MarkBitMap _verification_bit_map;
586 MarkBitMap _aux_bit_map;
587
588 size_t _bitmap_size;
589 size_t _bitmap_regions_per_slice;
590 size_t _bitmap_bytes_per_slice;
591
592 size_t _pretouch_heap_page_size;
593 size_t _pretouch_bitmap_page_size;
594
595 bool _bitmap_region_special;
596 bool _aux_bitmap_region_special;
597
598 ShenandoahLiveData** _liveness_cache;
599
600 public:
601 inline ShenandoahMarkingContext* complete_marking_context() const;
602 inline ShenandoahMarkingContext* marking_context() const;
603 inline void mark_complete_marking_context();
604 inline void mark_incomplete_marking_context();
605
606 template<class T>
607 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
608
609 template<class T>
610 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
611
612 template<class T>
613 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
614
615 void reset_mark_bitmap();
616
617 // SATB barriers hooks
618 inline bool requires_marking(const void* entry) const;
619
620 // Support for bitmap uncommits
621 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
622 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
623 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
624
625 // Liveness caching support
626 ShenandoahLiveData* get_liveness_cache(uint worker_id);
627 void flush_liveness_cache(uint worker_id);
628
629 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
630
631 // ---------- Evacuation support
632 //
633 private:
634 ShenandoahCollectionSet* _collection_set;
635 ShenandoahEvacOOMHandler _oom_evac_handler;
636
637 public:
638 static address in_cset_fast_test_addr();
639
640 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
641
642 // Checks if object is in the collection set.
643 inline bool in_collection_set(oop obj) const;
644
645 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
646 inline bool in_collection_set_loc(void* loc) const;
647
648 // Evacuates object src. Returns the evacuated object, either evacuated
649 // by this thread, or by some other thread.
650 oop evacuate_object(oop src, Thread* thread);
651
652 // Call before/after evacuation.
653 inline void enter_evacuation(Thread* t);
654 inline void leave_evacuation(Thread* t);
655
656 // ---------- Helper functions
657 //
658 public:
659 template <class T>
660 inline void conc_update_with_forwarded(T* p);
661
662 template <class T>
663 inline void non_conc_update_with_forwarded(T* p);
664
665 static inline void atomic_update_oop(oop update, oop* addr, oop compare);
666 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare);
667 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare);
668
669 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare);
670 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare);
671 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare);
672
673 static inline void atomic_clear_oop( oop* addr, oop compare);
674 static inline void atomic_clear_oop(narrowOop* addr, oop compare);
675 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare);
676
677 void trash_humongous_region_at(ShenandoahHeapRegion *r);
678
679 private:
680 void trash_cset_regions();
681
682 // ---------- Testing helpers functions
683 //
684 private:
685 ShenandoahSharedFlag _inject_alloc_failure;
686
687 void try_inject_alloc_failure();
688 bool should_inject_alloc_failure();
689 };
690
691 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP