1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
26
27 #include "gc_implementation/shared/markBitMap.hpp"
28 #include "gc_implementation/shenandoah/shenandoahAsserts.hpp"
29 #include "gc_implementation/shenandoah/shenandoahAllocRequest.hpp"
30 #include "gc_implementation/shenandoah/shenandoahHeapLock.hpp"
31 #include "gc_implementation/shenandoah/shenandoahEvacOOMHandler.hpp"
32 #include "gc_implementation/shenandoah/shenandoahSharedVariables.hpp"
33
34 class ConcurrentGCTimer;
35
36 class ShenandoahAllocTracker;
37 class ShenandoahCollectionSet;
38 class ShenandoahCollectorPolicy;
39 class ShenandoahConcurrentMark;
40 class ShenandoahControlThread;
41 class ShenandoahGCSession;
42 class ShenandoahFreeSet;
43 class ShenandoahHeapRegion;
44 class ShenandoahHeapRegionClosure;
45 class ShenandoahMarkCompact;
46 class ShenandoahMonitoringSupport;
47 class ShenandoahHeuristics;
48 class ShenandoahMarkingContext;
49 class ShenandoahPhaseTimings;
50 class ShenandoahPacer;
51 class ShenandoahVerifier;
52 class ShenandoahWorkGang;
53 class VMStructs;
54
55 class ShenandoahRegionIterator : public StackObj {
56 private:
57 ShenandoahHeap* _heap;
58
59 char _pad0[DEFAULT_CACHE_LINE_SIZE];
60 volatile jint _index;
61 char _pad1[DEFAULT_CACHE_LINE_SIZE];
62
63 // No implicit copying: iterators should be passed by reference to capture the state
64 ShenandoahRegionIterator(const ShenandoahRegionIterator& that);
65 ShenandoahRegionIterator& operator=(const ShenandoahRegionIterator& o);
66
67 public:
68 ShenandoahRegionIterator();
69 ShenandoahRegionIterator(ShenandoahHeap* heap);
70
71 // Reset iterator to default state
72 void reset();
73
74 // Returns next region, or NULL if there are no more regions.
75 // This is multi-thread-safe.
76 inline ShenandoahHeapRegion* next();
77
78 // This is *not* MT safe. However, in the absence of multithreaded access, it
79 // can be used to determine if there is more work to do.
80 bool has_next() const;
81 };
82
83 class ShenandoahHeapRegionClosure : public StackObj {
84 public:
85 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
86 virtual bool is_thread_safe() { return false; }
87 };
88
89 class ShenandoahUpdateRefsClosure: public OopClosure {
90 private:
91 ShenandoahHeap* _heap;
92
93 template <class T>
94 inline void do_oop_work(T* p);
95
96 public:
97 ShenandoahUpdateRefsClosure();
98 inline void do_oop(oop* p);
99 inline void do_oop(narrowOop* p);
100 };
101
102 #ifdef ASSERT
103 class ShenandoahAssertToSpaceClosure : public OopClosure {
104 private:
105 template <class T>
106 void do_oop_nv(T* p);
107 public:
108 void do_oop(narrowOop* p);
109 void do_oop(oop* p);
110 };
111 #endif
112
113 class ShenandoahAlwaysTrueClosure : public BoolObjectClosure {
114 public:
115 bool do_object_b(oop p) { return true; }
116 };
117
118 class ShenandoahForwardedIsAliveClosure: public BoolObjectClosure {
119 private:
120 ShenandoahMarkingContext* const _mark_context;
121 public:
122 ShenandoahForwardedIsAliveClosure();
123 bool do_object_b(oop obj);
124 };
125
126 class ShenandoahIsAliveClosure: public BoolObjectClosure {
127 private:
128 ShenandoahMarkingContext* const _mark_context;
129 public:
130 ShenandoahIsAliveClosure();
131 bool do_object_b(oop obj);
132 };
133
134 class ShenandoahIsAliveSelector : public StackObj {
135 private:
136 ShenandoahIsAliveClosure _alive_cl;
137 ShenandoahForwardedIsAliveClosure _fwd_alive_cl;
138 public:
139 BoolObjectClosure* is_alive_closure();
140 };
141
142 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
143 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
144 // See ShenandoahControlThread for GC cycle structure.
145 //
146 class ShenandoahHeap : public SharedHeap {
147 friend class ShenandoahAsserts;
148 friend class VMStructs;
149 friend class ShenandoahGCSession;
150
151 // ---------- Locks that guard important data structures in Heap
152 //
153 private:
154 ShenandoahHeapLock _lock;
155
156 public:
157 ShenandoahHeapLock* lock() {
158 return &_lock;
159 }
160
161 void assert_heaplock_owned_by_current_thread() NOT_DEBUG_RETURN;
162 void assert_heaplock_not_owned_by_current_thread() NOT_DEBUG_RETURN;
163 void assert_heaplock_or_safepoint() NOT_DEBUG_RETURN;
164
165 // ---------- Initialization, termination, identification, printing routines
166 //
167 public:
168 static ShenandoahHeap* heap();
169 static ShenandoahHeap* heap_no_check();
170 static size_t conservative_max_heap_alignment();
171
172 const char* name() const { return "Shenandoah"; }
173 ShenandoahHeap::Name kind() const { return CollectedHeap::ShenandoahHeap; }
174
175 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
176 jint initialize();
177 void post_initialize();
178 void initialize_heuristics();
179
180 void print_on(outputStream* st) const;
181 void print_extended_on(outputStream *st) const;
182 void print_tracing_info() const;
183 void print_gc_threads_on(outputStream* st) const;
184 void print_heap_regions_on(outputStream* st) const;
185
186 void stop();
187
188 void prepare_for_verify();
189 void verify(bool silent, VerifyOption vo);
190
191 // ---------- Heap counters and metrics
192 //
193 private:
194 size_t _initial_size;
195 char _pad0[DEFAULT_CACHE_LINE_SIZE];
196 volatile jlong _used;
197 volatile size_t _committed;
198 volatile jlong _bytes_allocated_since_gc_start;
199 char _pad1[DEFAULT_CACHE_LINE_SIZE];
200
201 public:
202 void increase_used(size_t bytes);
203 void decrease_used(size_t bytes);
204 void set_used(size_t bytes);
205
206 void increase_committed(size_t bytes);
207 void decrease_committed(size_t bytes);
208 void increase_allocated(size_t bytes);
209
210 size_t bytes_allocated_since_gc_start();
211 void reset_bytes_allocated_since_gc_start();
212
213 size_t max_capacity() const;
214 size_t initial_capacity() const;
215 size_t capacity() const;
216 size_t used() const;
217 size_t committed() const;
218
219 // ---------- Workers handling
220 //
221 private:
222 uint _max_workers;
223 ShenandoahWorkGang* _workers;
224
225 public:
226 uint max_workers();
227 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
228
229 ShenandoahWorkGang* workers() const;
230
231 void gc_threads_do(ThreadClosure* tcl) const;
232
233 // ---------- Heap regions handling machinery
234 //
235 private:
236 MemRegion _heap_region;
237 bool _heap_region_special;
238 size_t _num_regions;
239 ShenandoahHeapRegion** _regions;
240 ShenandoahRegionIterator _update_refs_iterator;
241
242 public:
243 inline size_t num_regions() const { return _num_regions; }
244 inline bool is_heap_region_special() { return _heap_region_special; }
245
246 inline ShenandoahHeapRegion* const heap_region_containing(const void* addr) const;
247 inline size_t heap_region_index_containing(const void* addr) const;
248
249 inline ShenandoahHeapRegion* const get_region(size_t region_idx) const;
250
251 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
252 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
253
254 // ---------- GC state machinery
255 //
256 // GC state describes the important parts of collector state, that may be
257 // used to make barrier selection decisions in the native and generated code.
258 // Multiple bits can be set at once.
259 //
260 // Important invariant: when GC state is zero, the heap is stable, and no barriers
261 // are required.
262 //
263 public:
264 enum GCStateBitPos {
265 // Heap has forwarded objects: need RB, ACMP, CAS barriers.
266 HAS_FORWARDED_BITPOS = 0,
267
268 // Heap is under marking: needs SATB barriers.
269 MARKING_BITPOS = 1,
270
271 // Heap is under evacuation: needs WB barriers. (Set together with UNSTABLE)
272 EVACUATION_BITPOS = 2,
273
274 // Heap is under updating: needs SVRB/SVWB barriers.
275 UPDATEREFS_BITPOS = 3,
276 };
277
278 enum GCState {
279 STABLE = 0,
280 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
281 MARKING = 1 << MARKING_BITPOS,
282 EVACUATION = 1 << EVACUATION_BITPOS,
283 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
284 };
285
286 private:
287 ShenandoahSharedBitmap _gc_state;
288 ShenandoahSharedFlag _degenerated_gc_in_progress;
289 ShenandoahSharedFlag _full_gc_in_progress;
290 ShenandoahSharedFlag _full_gc_move_in_progress;
291 ShenandoahSharedFlag _progress_last_gc;
292
293 void set_gc_state_mask(uint mask, bool value);
294
295 public:
296 char gc_state();
297 static address gc_state_addr();
298
299 void set_concurrent_mark_in_progress(bool in_progress);
300 void set_evacuation_in_progress(bool in_progress);
301 void set_update_refs_in_progress(bool in_progress);
302 void set_degenerated_gc_in_progress(bool in_progress);
303 void set_full_gc_in_progress(bool in_progress);
304 void set_full_gc_move_in_progress(bool in_progress);
305 void set_has_forwarded_objects(bool cond);
306
307 inline bool is_stable() const;
308 inline bool is_idle() const;
309 inline bool is_concurrent_mark_in_progress() const;
310 inline bool is_update_refs_in_progress() const;
311 inline bool is_evacuation_in_progress() const;
312 inline bool is_degenerated_gc_in_progress() const;
313 inline bool is_full_gc_in_progress() const;
314 inline bool is_full_gc_move_in_progress() const;
315 inline bool has_forwarded_objects() const;
316 inline bool is_gc_in_progress_mask(uint mask) const;
317
318 // ---------- GC cancellation and degeneration machinery
319 //
320 // Cancelled GC flag is used to notify concurrent phases that they should terminate.
321 //
322 public:
323 enum ShenandoahDegenPoint {
324 _degenerated_unset,
325 _degenerated_outside_cycle,
326 _degenerated_mark,
327 _degenerated_evac,
328 _degenerated_updaterefs,
329 _DEGENERATED_LIMIT,
330 };
331
332 static const char* degen_point_to_string(ShenandoahDegenPoint point) {
333 switch (point) {
334 case _degenerated_unset:
335 return "<UNSET>";
336 case _degenerated_outside_cycle:
337 return "Outside of Cycle";
338 case _degenerated_mark:
339 return "Mark";
340 case _degenerated_evac:
341 return "Evacuation";
342 case _degenerated_updaterefs:
343 return "Update Refs";
344 default:
345 ShouldNotReachHere();
346 return "ERROR";
347 }
348 };
349
350 private:
351 ShenandoahSharedFlag _cancelled_gc;
352 inline bool try_cancel_gc();
353
354 public:
355 static address cancelled_gc_addr();
356
357 inline bool cancelled_gc() const;
358
359 inline void clear_cancelled_gc();
360
361 void cancel_gc(GCCause::Cause cause);
362
363 // ---------- GC operations entry points
364 //
365 public:
366 // Entry points to STW GC operations, these cause a related safepoint, that then
367 // call the entry method below
368 void vmop_entry_init_mark();
369 void vmop_entry_final_mark();
370 void vmop_entry_final_evac();
371 void vmop_entry_init_updaterefs();
372 void vmop_entry_final_updaterefs();
373 void vmop_entry_full(GCCause::Cause cause);
374 void vmop_degenerated(ShenandoahDegenPoint point);
375
376 // Entry methods to normally STW GC operations. These set up logging, monitoring
377 // and workers for net VM operation
378 void entry_init_mark();
379 void entry_final_mark();
380 void entry_final_evac();
381 void entry_init_updaterefs();
382 void entry_final_updaterefs();
383 void entry_full(GCCause::Cause cause);
384 void entry_degenerated(int point);
385
386 // Entry methods to normally concurrent GC operations. These set up logging, monitoring
387 // for concurrent operation.
388 void entry_reset();
389 void entry_mark();
390 void entry_preclean();
391 void entry_cleanup();
392 void entry_evac();
393 void entry_updaterefs();
394 void entry_uncommit(double shrink_before);
395
396 private:
397 // Actual work for the phases
398 void op_init_mark();
399 void op_final_mark();
400 void op_final_evac();
401 void op_init_updaterefs();
402 void op_final_updaterefs();
403 void op_full(GCCause::Cause cause);
404 void op_degenerated(ShenandoahDegenPoint point);
405 void op_degenerated_fail();
406 void op_degenerated_futile();
407
408 void op_reset();
409 void op_mark();
410 void op_preclean();
411 void op_cleanup();
412 void op_conc_evac();
413 void op_stw_evac();
414 void op_updaterefs();
415 void op_uncommit(double shrink_before);
416
417 // Messages for GC trace event, they have to be immortal for
418 // passing around the logging/tracing systems
419 const char* init_mark_event_message() const;
420 const char* final_mark_event_message() const;
421 const char* conc_mark_event_message() const;
422 const char* degen_event_message(ShenandoahDegenPoint point) const;
423
424 // ---------- GC subsystems
425 //
426 private:
427 ShenandoahControlThread* _control_thread;
428 ShenandoahCollectorPolicy* _shenandoah_policy;
429 ShenandoahHeuristics* _heuristics;
430 ShenandoahFreeSet* _free_set;
431 ShenandoahConcurrentMark* _scm;
432 ShenandoahMarkCompact* _full_gc;
433 ShenandoahPacer* _pacer;
434 ShenandoahVerifier* _verifier;
435
436 ShenandoahAllocTracker* _alloc_tracker;
437 ShenandoahPhaseTimings* _phase_timings;
438
439 ShenandoahControlThread* control_thread() { return _control_thread; }
440 ShenandoahMarkCompact* full_gc() { return _full_gc; }
441
442 public:
443 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
444 ShenandoahHeuristics* heuristics() const { return _heuristics; }
445 ShenandoahFreeSet* free_set() const { return _free_set; }
446 ShenandoahConcurrentMark* concurrent_mark() { return _scm; }
447 ShenandoahPacer* pacer() const { return _pacer; }
448
449 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
450 ShenandoahAllocTracker* alloc_tracker() const { return _alloc_tracker; }
451
452 ShenandoahVerifier* verifier();
453
454 // ---------- VM subsystem bindings
455 //
456 private:
457 ShenandoahMonitoringSupport* _monitoring_support;
458 ConcurrentGCTimer* _gc_timer;
459
460 public:
461 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
462
463 GCTracer* tracer();
464 GCTimer* gc_timer() const;
465 CollectorPolicy* collector_policy() const;
466
467 // ---------- Reference processing
468 //
469 private:
470 ReferenceProcessor* _ref_processor;
471 ShenandoahSharedFlag _process_references;
472
473 void ref_processing_init();
474
475 public:
476 ReferenceProcessor* ref_processor() { return _ref_processor;}
477 void set_process_references(bool pr);
478 bool process_references() const;
479
480 // ---------- Class Unloading
481 //
482 private:
483 ShenandoahSharedFlag _unload_classes;
484
485 public:
486 void set_unload_classes(bool uc);
487 bool unload_classes() const;
488
489 // Delete entries for dead interned string and clean up unreferenced symbols
490 // in symbol table, possibly in parallel.
491 void unload_classes_and_cleanup_tables(bool full_gc);
492
493 // ---------- Generic interface hooks
494 // Minor things that super-interface expects us to implement to play nice with
495 // the rest of runtime. Some of the things here are not required to be implemented,
496 // and can be stubbed out.
497 //
498 public:
499 AdaptiveSizePolicy* size_policy() shenandoah_not_implemented_return(NULL);
500 bool is_maximal_no_gc() const shenandoah_not_implemented_return(false);
501
502 bool is_in(const void* p) const;
503
504 // All objects can potentially move
505 bool is_scavengable(const void* addr) { return true; }
506
507 void collect(GCCause::Cause cause);
508 void do_full_collection(bool clear_all_soft_refs);
509
510 // Used for parsing heap during error printing
511 HeapWord* block_start(const void* addr) const;
512 size_t block_size(const HeapWord* addr) const;
513 bool block_is_obj(const HeapWord* addr) const;
514
515 // Used for native heap walkers: heap dumpers, mostly
516 void object_iterate(ObjectClosure* cl);
517 void safe_object_iterate(ObjectClosure* cl);
518 void space_iterate(SpaceClosure* scl);
519 void oop_iterate(ExtendedOopClosure* cl);
520 Space* space_containing(const void* oop) const;
521
522 // Used by RMI
523 jlong millis_since_last_gc();
524
525 bool can_elide_tlab_store_barriers() const { return true; }
526 oop new_store_pre_barrier(JavaThread* thread, oop new_obj) { return new_obj; }
527 bool can_elide_initializing_store_barrier(oop new_obj) { return true; }
528 bool card_mark_must_follow_store() const { return false; }
529
530 bool is_in_partial_collection(const void* p) shenandoah_not_implemented_return(false);
531 bool supports_heap_inspection() const { return true; }
532
533 void gc_prologue(bool b);
534 void gc_epilogue(bool b);
535
536 void acquire_pending_refs_lock();
537 void release_pending_refs_lock();
538
539 // ---------- Code roots handling hooks
540 //
541 public:
542 void register_nmethod(nmethod* nm);
543 void unregister_nmethod(nmethod* nm);
544
545 // ---------- Pinning hooks
546 //
547 public:
548 // Shenandoah supports per-object (per-region) pinning
549 bool supports_object_pinning() const { return true; }
550
551 oop pin_object(JavaThread* thread, oop obj);
552 void unpin_object(JavaThread* thread, oop obj);
553
554 // ---------- Allocation support
555 //
556 private:
557 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
558 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
559 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
560 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
561
562 public:
563 #ifndef CC_INTERP
564 void compile_prepare_oop(MacroAssembler* masm, Register obj);
565 #endif
566
567 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
568 HeapWord* mem_allocate(size_t size, bool* what);
569
570 uint oop_extra_words();
571
572 void notify_mutator_alloc_words(size_t words, bool waste);
573
574 // Shenandoah supports TLAB allocation
575 bool supports_tlab_allocation() const { return true; }
576
577 HeapWord* allocate_new_tlab(size_t word_size);
578 size_t tlab_capacity(Thread *thr) const;
579 size_t unsafe_max_tlab_alloc(Thread *thread) const;
580 size_t max_tlab_size() const;
581 size_t tlab_used(Thread* ignored) const;
582
583 HeapWord* tlab_post_allocation_setup(HeapWord* obj);
584
585 void resize_tlabs();
586 void resize_all_tlabs();
587
588 void accumulate_statistics_tlabs();
589 void accumulate_statistics_all_gclabs();
590
591 void make_parsable(bool retire_tlabs);
592 void ensure_parsability(bool retire_tlabs);
593
594 // ---------- Marking support
595 //
596 private:
597 ShenandoahMarkingContext* _marking_context;
598 MemRegion _bitmap_region;
599 MemRegion _aux_bitmap_region;
600 MarkBitMap _verification_bit_map;
601 MarkBitMap _aux_bit_map;
602
603 size_t _bitmap_size;
604 size_t _bitmap_regions_per_slice;
605 size_t _bitmap_bytes_per_slice;
606
607 bool _bitmap_region_special;
608 bool _aux_bitmap_region_special;
609
610 // Used for buffering per-region liveness data.
611 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
612 //
613 // The array has max-workers elements, each of which is an array of
614 // jushort * max_regions. The choice of jushort is not accidental:
615 // there is a tradeoff between static/dynamic footprint that translates
616 // into cache pressure (which is already high during marking), and
617 // too many atomic updates. size_t/jint is too large, jbyte is too small.
618 jushort** _liveness_cache;
619
620 public:
621 inline ShenandoahMarkingContext* complete_marking_context() const;
622 inline ShenandoahMarkingContext* marking_context() const;
623 inline void mark_complete_marking_context();
624 inline void mark_incomplete_marking_context();
625
626 template<class T>
627 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
628
629 template<class T>
630 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
631
632 template<class T>
633 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
634
635 void reset_mark_bitmap();
636
637 // SATB barriers hooks
638 inline bool requires_marking(const void* entry) const;
639 void force_satb_flush_all_threads();
640
641 // Support for bitmap uncommits
642 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
643 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
644 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
645
646 // Liveness caching support
647 jushort* get_liveness_cache(uint worker_id);
648 void flush_liveness_cache(uint worker_id);
649
650 // ---------- Evacuation support
651 //
652 private:
653 ShenandoahCollectionSet* _collection_set;
654 ShenandoahEvacOOMHandler _oom_evac_handler;
655
656 void evacuate_and_update_roots();
657
658 public:
659 static address in_cset_fast_test_addr();
660
661 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
662
663 template <class T>
664 inline bool in_collection_set(T obj) const;
665
666 // Avoid accidentally calling the method above with ShenandoahHeapRegion*, which would be *wrong*.
667 inline bool in_collection_set(ShenandoahHeapRegion* r) shenandoah_not_implemented_return(false);
668
669 // Evacuates object src. Returns the evacuated object, either evacuated
670 // by this thread, or by some other thread.
671 inline oop evacuate_object(oop src, Thread* thread, bool& evacuated);
672
673 // Call before/after evacuation.
674 void enter_evacuation();
675 void leave_evacuation();
676
677 // ---------- Helper functions
678 //
679 public:
680 template <class T>
681 inline oop maybe_update_with_forwarded(T* p);
682
683 template <class T>
684 inline oop maybe_update_with_forwarded_not_null(T* p, oop obj);
685
686 template <class T>
687 inline oop update_with_forwarded_not_null(T* p, oop obj);
688
689 inline oop atomic_compare_exchange_oop(oop n, narrowOop* addr, oop c);
690 inline oop atomic_compare_exchange_oop(oop n, oop* addr, oop c);
691
692 void trash_humongous_region_at(ShenandoahHeapRegion *r);
693
694 void stop_concurrent_marking();
695
696 void roots_iterate(OopClosure* cl);
697
698 private:
699 void trash_cset_regions();
700 void update_heap_references(bool concurrent);
701
702 // ---------- Testing helpers functions
703 //
704 private:
705 ShenandoahSharedFlag _inject_alloc_failure;
706
707 void try_inject_alloc_failure();
708 bool should_inject_alloc_failure();
709 };
710
711 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_HPP