1 /*
2 * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
27
28 #include "gc/shared/markBitMap.hpp"
29 #include "gc/shared/softRefPolicy.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "gc/shenandoah/shenandoahAsserts.hpp"
32 #include "gc/shenandoah/shenandoahAllocRequest.hpp"
33 #include "gc/shenandoah/shenandoahLock.hpp"
34 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
35 #include "gc/shenandoah/shenandoahPadding.hpp"
36 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
37 #include "gc/shenandoah/shenandoahUnload.hpp"
38 #include "services/memoryManager.hpp"
39 #include "utilities/globalDefinitions.hpp"
40
41 class ConcurrentGCTimer;
42 class ReferenceProcessor;
43 class ShenandoahCollectorPolicy;
44 class ShenandoahControlThread;
45 class ShenandoahGCSession;
46 class ShenandoahGCStateResetter;
47 class ShenandoahHeuristics;
48 class ShenandoahMarkingContext;
49 class ShenandoahMarkCompact;
50 class ShenandoahMode;
51 class ShenandoahPhaseTimings;
52 class ShenandoahHeap;
53 class ShenandoahHeapRegion;
54 class ShenandoahHeapRegionClosure;
55 class ShenandoahCollectionSet;
56 class ShenandoahFreeSet;
57 class ShenandoahConcurrentMark;
58 class ShenandoahMarkCompact;
59 class ShenandoahMonitoringSupport;
60 class ShenandoahPacer;
61 class ShenandoahVerifier;
62 class ShenandoahWorkGang;
63 class VMStructs;
64
65 // Used for buffering per-region liveness data.
66 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
67 // The ShenandoahHeap array has max-workers elements, each of which is an array of
68 // uint16_t * max_regions. The choice of uint16_t is not accidental:
69 // there is a tradeoff between static/dynamic footprint that translates
70 // into cache pressure (which is already high during marking), and
71 // too many atomic updates. uint32_t is too large, uint8_t is too small.
72 typedef uint16_t ShenandoahLiveData;
73 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1)
74
75 class ShenandoahRegionIterator : public StackObj {
76 private:
77 ShenandoahHeap* _heap;
78
79 shenandoah_padding(0);
80 volatile size_t _index;
81 shenandoah_padding(1);
82
83 // No implicit copying: iterators should be passed by reference to capture the state
84 NONCOPYABLE(ShenandoahRegionIterator);
85
86 public:
87 ShenandoahRegionIterator();
88 ShenandoahRegionIterator(ShenandoahHeap* heap);
89
90 // Reset iterator to default state
91 void reset();
92
93 // Returns next region, or NULL if there are no more regions.
94 // This is multi-thread-safe.
95 inline ShenandoahHeapRegion* next();
96
97 // This is *not* MT safe. However, in the absence of multithreaded access, it
98 // can be used to determine if there is more work to do.
99 bool has_next() const;
100 };
101
102 class ShenandoahHeapRegionClosure : public StackObj {
103 public:
104 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
105 virtual bool is_thread_safe() { return false; }
106 };
107
108 #ifdef ASSERT
109 class ShenandoahAssertToSpaceClosure : public OopClosure {
110 private:
111 template <class T>
112 void do_oop_work(T* p);
113 public:
114 void do_oop(narrowOop* p);
115 void do_oop(oop* p);
116 };
117 #endif
118
119 typedef ShenandoahLock ShenandoahHeapLock;
120 typedef ShenandoahLocker ShenandoahHeapLocker;
121
122 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
123 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
124 // See ShenandoahControlThread for GC cycle structure.
125 //
126 class ShenandoahHeap : public CollectedHeap {
127 friend class ShenandoahAsserts;
128 friend class VMStructs;
129 friend class ShenandoahGCSession;
130 friend class ShenandoahGCStateResetter;
131
132 // ---------- Locks that guard important data structures in Heap
133 //
134 private:
135 ShenandoahHeapLock _lock;
136
137 public:
138 ShenandoahHeapLock* lock() {
139 return &_lock;
140 }
141
142 // ---------- Initialization, termination, identification, printing routines
143 //
144 private:
145 static ShenandoahHeap* _heap;
146
147 public:
148 static ShenandoahHeap* heap();
149
150 const char* name() const { return "Shenandoah"; }
151 ShenandoahHeap::Name kind() const { return CollectedHeap::Shenandoah; }
152
153 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
154 jint initialize();
155 void post_initialize();
156 void initialize_heuristics();
157
158 void initialize_serviceability();
159
160 void print_on(outputStream* st) const;
161 void print_extended_on(outputStream *st) const;
162 void print_tracing_info() const;
163 void print_heap_regions_on(outputStream* st) const;
164
165 void stop();
166
167 void prepare_for_verify();
168 void verify(VerifyOption vo);
169
170 // ---------- Heap counters and metrics
171 //
172 private:
173 size_t _initial_size;
174 size_t _minimum_size;
175 shenandoah_padding(0);
176 volatile size_t _used;
177 volatile size_t _committed;
178 volatile size_t _bytes_allocated_since_gc_start;
179 shenandoah_padding(1);
180
181 public:
182 void increase_used(size_t bytes);
183 void decrease_used(size_t bytes);
184 void set_used(size_t bytes);
185
186 void increase_committed(size_t bytes);
187 void decrease_committed(size_t bytes);
188 void increase_allocated(size_t bytes);
189
190 size_t bytes_allocated_since_gc_start();
191 void reset_bytes_allocated_since_gc_start();
192
193 size_t min_capacity() const;
194 size_t max_capacity() const;
195 size_t initial_capacity() const;
196 size_t capacity() const;
197 size_t used() const;
198 size_t committed() const;
199
200 // ---------- Workers handling
201 //
202 private:
203 uint _max_workers;
204 ShenandoahWorkGang* _workers;
205 ShenandoahWorkGang* _safepoint_workers;
206
207 public:
208 uint max_workers();
209 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
210
211 WorkGang* workers() const;
212 WorkGang* get_safepoint_workers();
213
214 void gc_threads_do(ThreadClosure* tcl) const;
215
216 // ---------- Heap regions handling machinery
217 //
218 private:
219 MemRegion _heap_region;
220 bool _heap_region_special;
221 size_t _num_regions;
222 ShenandoahHeapRegion** _regions;
223 ShenandoahRegionIterator _update_refs_iterator;
224
225 public:
226
227 inline HeapWord* base() const { return _heap_region.start(); }
228
229 inline size_t num_regions() const { return _num_regions; }
230 inline bool is_heap_region_special() { return _heap_region_special; }
231
232 inline ShenandoahHeapRegion* const heap_region_containing(const void* addr) const;
233 inline size_t heap_region_index_containing(const void* addr) const;
234
235 inline ShenandoahHeapRegion* const get_region(size_t region_idx) const;
236
237 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
238 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
239
240 // ---------- GC state machinery
241 //
242 // GC state describes the important parts of collector state, that may be
243 // used to make barrier selection decisions in the native and generated code.
244 // Multiple bits can be set at once.
245 //
246 // Important invariant: when GC state is zero, the heap is stable, and no barriers
247 // are required.
248 //
249 public:
250 enum GCStateBitPos {
251 // Heap has forwarded objects: needs LRB barriers.
252 HAS_FORWARDED_BITPOS = 0,
253
254 // Heap is under marking: needs SATB barriers.
255 MARKING_BITPOS = 1,
256
257 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
258 EVACUATION_BITPOS = 2,
259
260 // Heap is under updating: needs no additional barriers.
261 UPDATEREFS_BITPOS = 3,
262 };
263
264 enum GCState {
265 STABLE = 0,
266 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
267 MARKING = 1 << MARKING_BITPOS,
268 EVACUATION = 1 << EVACUATION_BITPOS,
269 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
270 };
271
272 private:
273 ShenandoahSharedBitmap _gc_state;
274 ShenandoahSharedFlag _degenerated_gc_in_progress;
275 ShenandoahSharedFlag _full_gc_in_progress;
276 ShenandoahSharedFlag _full_gc_move_in_progress;
277 ShenandoahSharedFlag _progress_last_gc;
278 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
279 ShenandoahSharedFlag _concurrent_weak_root_in_progress;
280
281 void set_gc_state_all_threads(char state);
282 void set_gc_state_mask(uint mask, bool value);
283
284 public:
285 char gc_state() const;
286 static address gc_state_addr();
287
288 void set_concurrent_mark_in_progress(bool in_progress);
289 void set_evacuation_in_progress(bool in_progress);
290 void set_update_refs_in_progress(bool in_progress);
291 void set_degenerated_gc_in_progress(bool in_progress);
292 void set_full_gc_in_progress(bool in_progress);
293 void set_full_gc_move_in_progress(bool in_progress);
294 void set_has_forwarded_objects(bool cond);
295 void set_concurrent_strong_root_in_progress(bool cond);
296 void set_concurrent_weak_root_in_progress(bool cond);
297
298 inline bool is_stable() const;
299 inline bool is_idle() const;
300 inline bool is_concurrent_mark_in_progress() const;
301 inline bool is_update_refs_in_progress() const;
302 inline bool is_evacuation_in_progress() const;
303 inline bool is_degenerated_gc_in_progress() const;
304 inline bool is_full_gc_in_progress() const;
305 inline bool is_full_gc_move_in_progress() const;
306 inline bool has_forwarded_objects() const;
307 inline bool is_gc_in_progress_mask(uint mask) const;
308 inline bool is_stw_gc_in_progress() const;
309 inline bool is_concurrent_strong_root_in_progress() const;
310 inline bool is_concurrent_weak_root_in_progress() const;
311
312 // ---------- GC cancellation and degeneration machinery
313 //
314 // Cancelled GC flag is used to notify concurrent phases that they should terminate.
315 //
316 public:
317 enum ShenandoahDegenPoint {
318 _degenerated_unset,
319 _degenerated_outside_cycle,
320 _degenerated_mark,
321 _degenerated_evac,
322 _degenerated_updaterefs,
323 _DEGENERATED_LIMIT
324 };
325
326 static const char* degen_point_to_string(ShenandoahDegenPoint point) {
327 switch (point) {
328 case _degenerated_unset:
329 return "<UNSET>";
330 case _degenerated_outside_cycle:
331 return "Outside of Cycle";
332 case _degenerated_mark:
333 return "Mark";
334 case _degenerated_evac:
335 return "Evacuation";
336 case _degenerated_updaterefs:
337 return "Update Refs";
338 default:
339 ShouldNotReachHere();
340 return "ERROR";
341 }
342 };
343
344 private:
345 enum CancelState {
346 // Normal state. GC has not been cancelled and is open for cancellation.
347 // Worker threads can suspend for safepoint.
348 CANCELLABLE,
349
350 // GC has been cancelled. Worker threads can not suspend for
351 // safepoint but must finish their work as soon as possible.
352 CANCELLED,
353
354 // GC has not been cancelled and must not be cancelled. At least
355 // one worker thread checks for pending safepoint and may suspend
356 // if a safepoint is pending.
357 NOT_CANCELLED
358 };
359
360 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
361 bool try_cancel_gc();
362
363 public:
364 static address cancelled_gc_addr();
365
366 inline bool cancelled_gc() const;
367 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
368
369 inline void clear_cancelled_gc();
370
371 void cancel_gc(GCCause::Cause cause);
372
373 // ---------- GC operations entry points
374 //
375 public:
376 // Entry points to STW GC operations, these cause a related safepoint, that then
377 // call the entry method below
378 void vmop_entry_init_mark();
379 void vmop_entry_final_mark();
380 void vmop_entry_init_updaterefs();
381 void vmop_entry_final_updaterefs();
382 void vmop_entry_full(GCCause::Cause cause);
383 void vmop_degenerated(ShenandoahDegenPoint point);
384
385 // Entry methods to normally STW GC operations. These set up logging, monitoring
386 // and workers for net VM operation
387 void entry_init_mark();
388 void entry_final_mark();
389 void entry_init_updaterefs();
390 void entry_final_updaterefs();
391 void entry_full(GCCause::Cause cause);
392 void entry_degenerated(int point);
393
394 // Entry methods to normally concurrent GC operations. These set up logging, monitoring
395 // for concurrent operation.
396 void entry_reset();
397 void entry_mark();
398 void entry_preclean();
399 void entry_weak_roots();
400 void entry_class_unloading();
401 void entry_strong_roots();
402 void entry_cleanup_early();
403 void entry_evac();
404 void entry_updaterefs();
405 void entry_cleanup_complete();
406 void entry_uncommit(double shrink_before);
407
408 private:
409 // Actual work for the phases
410 void op_init_mark();
411 void op_final_mark();
412 void op_init_updaterefs();
413 void op_final_updaterefs();
414 void op_full(GCCause::Cause cause);
415 void op_degenerated(ShenandoahDegenPoint point);
416 void op_degenerated_fail();
417 void op_degenerated_futile();
418
419 void op_reset();
420 void op_mark();
421 void op_preclean();
422 void op_weak_roots();
423 void op_class_unloading();
424 void op_strong_roots();
425 void op_cleanup_early();
426 void op_conc_evac();
427 void op_stw_evac();
428 void op_updaterefs();
429 void op_cleanup_complete();
430 void op_uncommit(double shrink_before);
431
432 // Messages for GC trace events, they have to be immortal for
433 // passing around the logging/tracing systems
434 const char* init_mark_event_message() const;
435 const char* final_mark_event_message() const;
436 const char* conc_mark_event_message() const;
437 const char* degen_event_message(ShenandoahDegenPoint point) const;
438
439 // ---------- GC subsystems
440 //
441 private:
442 ShenandoahControlThread* _control_thread;
443 ShenandoahCollectorPolicy* _shenandoah_policy;
444 ShenandoahMode* _gc_mode;
445 ShenandoahHeuristics* _heuristics;
446 ShenandoahFreeSet* _free_set;
447 ShenandoahConcurrentMark* _scm;
448 ShenandoahMarkCompact* _full_gc;
449 ShenandoahPacer* _pacer;
450 ShenandoahVerifier* _verifier;
451
452 ShenandoahPhaseTimings* _phase_timings;
453
454 ShenandoahControlThread* control_thread() { return _control_thread; }
455 ShenandoahMarkCompact* full_gc() { return _full_gc; }
456
457 public:
458 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
459 ShenandoahMode* mode() const { return _gc_mode; }
460 ShenandoahHeuristics* heuristics() const { return _heuristics; }
461 ShenandoahFreeSet* free_set() const { return _free_set; }
462 ShenandoahConcurrentMark* concurrent_mark() { return _scm; }
463 ShenandoahPacer* pacer() const { return _pacer; }
464
465 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
466
467 ShenandoahVerifier* verifier();
468
469 // ---------- VM subsystem bindings
470 //
471 private:
472 ShenandoahMonitoringSupport* _monitoring_support;
473 MemoryPool* _memory_pool;
474 GCMemoryManager _stw_memory_manager;
475 GCMemoryManager _cycle_memory_manager;
476 ConcurrentGCTimer* _gc_timer;
477 SoftRefPolicy _soft_ref_policy;
478
479 // For exporting to SA
480 int _log_min_obj_alignment_in_bytes;
481 public:
482 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
483 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
484 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
485 SoftRefPolicy* soft_ref_policy() { return &_soft_ref_policy; }
486
487 GrowableArray<GCMemoryManager*> memory_managers();
488 GrowableArray<MemoryPool*> memory_pools();
489 MemoryUsage memory_usage();
490 GCTracer* tracer();
491 ConcurrentGCTimer* gc_timer() const;
492
493 // ---------- Reference processing
494 //
495 private:
496 AlwaysTrueClosure _subject_to_discovery;
497 ReferenceProcessor* _ref_processor;
498 ShenandoahSharedFlag _process_references;
499 bool _ref_proc_mt_discovery;
500 bool _ref_proc_mt_processing;
501
502 void ref_processing_init();
503
504 public:
505 ReferenceProcessor* ref_processor() { return _ref_processor; }
506 bool ref_processor_mt_discovery() { return _ref_proc_mt_discovery; }
507 bool ref_processor_mt_processing() { return _ref_proc_mt_processing; }
508 void set_process_references(bool pr);
509 bool process_references() const;
510
511 // ---------- Class Unloading
512 //
513 private:
514 ShenandoahSharedFlag _unload_classes;
515 ShenandoahUnload _unloader;
516
517 public:
518 void set_unload_classes(bool uc);
519 bool unload_classes() const;
520
521 // Perform STW class unloading and weak root cleaning
522 void parallel_cleaning(bool full_gc);
523
524 private:
525 void stw_unload_classes(bool full_gc);
526 void stw_process_weak_roots(bool full_gc);
527
528 // Prepare concurrent root processing
529 void prepare_concurrent_roots();
530 // Prepare and finish concurrent unloading
531 void prepare_concurrent_unloading();
532 void finish_concurrent_unloading();
533
534 // ---------- Generic interface hooks
535 // Minor things that super-interface expects us to implement to play nice with
536 // the rest of runtime. Some of the things here are not required to be implemented,
537 // and can be stubbed out.
538 //
539 public:
540 AdaptiveSizePolicy* size_policy() shenandoah_not_implemented_return(NULL);
541 bool is_maximal_no_gc() const shenandoah_not_implemented_return(false);
542
543 bool is_in(const void* p) const;
544
545 MemRegion reserved_region() const { return _reserved; }
546 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
547
548 void collect(GCCause::Cause cause);
549 void do_full_collection(bool clear_all_soft_refs);
550
551 // Used for parsing heap during error printing
552 HeapWord* block_start(const void* addr) const;
553 bool block_is_obj(const HeapWord* addr) const;
554 bool print_location(outputStream* st, void* addr) const;
555
556 // Used for native heap walkers: heap dumpers, mostly
557 void object_iterate(ObjectClosure* cl);
558
559 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
560 void keep_alive(oop obj);
561
562 // Used by RMI
563 jlong millis_since_last_gc();
564
565 // ---------- Safepoint interface hooks
566 //
567 public:
568 void safepoint_synchronize_begin();
569 void safepoint_synchronize_end();
570
571 // ---------- Code roots handling hooks
572 //
573 public:
574 void register_nmethod(nmethod* nm);
575 void unregister_nmethod(nmethod* nm);
576 void flush_nmethod(nmethod* nm);
577 void verify_nmethod(nmethod* nm) {}
578
579 // ---------- Pinning hooks
580 //
581 public:
582 // Shenandoah supports per-object (per-region) pinning
583 bool supports_object_pinning() const { return true; }
584
585 oop pin_object(JavaThread* thread, oop obj);
586 void unpin_object(JavaThread* thread, oop obj);
587
588 void sync_pinned_region_status();
589 void assert_pinned_region_status() NOT_DEBUG_RETURN;
590
591 // ---------- Allocation support
592 //
593 private:
594 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
595 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
596 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
597 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
598 void retire_and_reset_gclabs();
599
600 public:
601 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
602 HeapWord* mem_allocate(size_t size, bool* what);
603 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
604 size_t size,
605 Metaspace::MetadataType mdtype);
606
607 void notify_mutator_alloc_words(size_t words, bool waste);
608
609 // Shenandoah supports TLAB allocation
610 bool supports_tlab_allocation() const { return true; }
611
612 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size);
613 size_t tlab_capacity(Thread *thr) const;
614 size_t unsafe_max_tlab_alloc(Thread *thread) const;
615 size_t max_tlab_size() const;
616 size_t tlab_used(Thread* ignored) const;
617
618 void resize_tlabs();
619
620 void ensure_parsability(bool retire_tlabs);
621 void make_parsable(bool retire_tlabs);
622
623 // ---------- Marking support
624 //
625 private:
626 ShenandoahMarkingContext* _marking_context;
627 MemRegion _bitmap_region;
628 MemRegion _aux_bitmap_region;
629 MarkBitMap _verification_bit_map;
630 MarkBitMap _aux_bit_map;
631
632 size_t _bitmap_size;
633 size_t _bitmap_regions_per_slice;
634 size_t _bitmap_bytes_per_slice;
635
636 size_t _pretouch_heap_page_size;
637 size_t _pretouch_bitmap_page_size;
638
639 bool _bitmap_region_special;
640 bool _aux_bitmap_region_special;
641
642 ShenandoahLiveData** _liveness_cache;
643
644 public:
645 inline ShenandoahMarkingContext* complete_marking_context() const;
646 inline ShenandoahMarkingContext* marking_context() const;
647 inline void mark_complete_marking_context();
648 inline void mark_incomplete_marking_context();
649
650 template<class T>
651 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
652
653 template<class T>
654 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
655
656 template<class T>
657 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
658
659 void reset_mark_bitmap();
660
661 // SATB barriers hooks
662 template<bool RESOLVE>
663 inline bool requires_marking(const void* entry) const;
664 void force_satb_flush_all_threads();
665
666 // Support for bitmap uncommits
667 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
668 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
669 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
670
671 // Liveness caching support
672 ShenandoahLiveData* get_liveness_cache(uint worker_id);
673 void flush_liveness_cache(uint worker_id);
674
675 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
676
677 // ---------- Evacuation support
678 //
679 private:
680 ShenandoahCollectionSet* _collection_set;
681 ShenandoahEvacOOMHandler _oom_evac_handler;
682
683 void evacuate_and_update_roots();
684
685 public:
686 static address in_cset_fast_test_addr();
687
688 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
689
690 // Checks if object is in the collection set.
691 inline bool in_collection_set(oop obj) const;
692
693 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
694 inline bool in_collection_set_loc(void* loc) const;
695
696 // Evacuates object src. Returns the evacuated object, either evacuated
697 // by this thread, or by some other thread.
698 inline oop evacuate_object(oop src, Thread* thread);
699
700 // Call before/after evacuation.
701 inline void enter_evacuation(Thread* t);
702 inline void leave_evacuation(Thread* t);
703
704 // ---------- Helper functions
705 //
706 public:
707 template <class T>
708 inline oop evac_update_with_forwarded(T* p);
709
710 template <class T>
711 inline oop maybe_update_with_forwarded(T* p);
712
713 template <class T>
714 inline oop maybe_update_with_forwarded_not_null(T* p, oop obj);
715
716 template <class T>
717 inline oop update_with_forwarded_not_null(T* p, oop obj);
718
719 static inline oop cas_oop(oop n, narrowOop* addr, oop c);
720 static inline oop cas_oop(oop n, oop* addr, oop c);
721 static inline oop cas_oop(oop n, narrowOop* addr, narrowOop c);
722
723 void trash_humongous_region_at(ShenandoahHeapRegion *r);
724
725 void deduplicate_string(oop str);
726
727 private:
728 void trash_cset_regions();
729 void update_heap_references(bool concurrent);
730
731 // ---------- Testing helpers functions
732 //
733 private:
734 ShenandoahSharedFlag _inject_alloc_failure;
735
736 void try_inject_alloc_failure();
737 bool should_inject_alloc_failure();
738 };
739
740 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP