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 public:
145 static ShenandoahHeap* heap();
146
147 const char* name() const { return "Shenandoah"; }
148 ShenandoahHeap::Name kind() const { return CollectedHeap::Shenandoah; }
149
150 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
151 jint initialize();
152 void post_initialize();
153 void initialize_heuristics();
154
155 void initialize_serviceability();
156
157 void print_on(outputStream* st) const;
158 void print_extended_on(outputStream *st) const;
159 void print_tracing_info() const;
160 void print_heap_regions_on(outputStream* st) const;
161
162 void stop();
163
164 void prepare_for_verify();
165 void verify(VerifyOption vo);
166
167 // ---------- Heap counters and metrics
168 //
169 private:
170 size_t _initial_size;
171 size_t _minimum_size;
172 shenandoah_padding(0);
173 volatile size_t _used;
174 volatile size_t _committed;
175 volatile size_t _bytes_allocated_since_gc_start;
176 shenandoah_padding(1);
177
178 public:
179 void increase_used(size_t bytes);
180 void decrease_used(size_t bytes);
181 void set_used(size_t bytes);
182
183 void increase_committed(size_t bytes);
184 void decrease_committed(size_t bytes);
185 void increase_allocated(size_t bytes);
186
187 size_t bytes_allocated_since_gc_start();
188 void reset_bytes_allocated_since_gc_start();
189
190 size_t min_capacity() const;
191 size_t max_capacity() const;
192 size_t initial_capacity() const;
193 size_t capacity() const;
194 size_t used() const;
195 size_t committed() const;
196
197 // ---------- Workers handling
198 //
199 private:
200 uint _max_workers;
201 ShenandoahWorkGang* _workers;
202 ShenandoahWorkGang* _safepoint_workers;
203
204 public:
205 uint max_workers();
206 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
207
208 WorkGang* workers() const;
209 WorkGang* get_safepoint_workers();
210
211 void gc_threads_do(ThreadClosure* tcl) const;
212 // Runs the given AbstractGangTask with the current active workers.
213 virtual void run_task(AbstractGangTask* task);
214
215 // ---------- Heap regions handling machinery
216 //
217 private:
218 MemRegion _heap_region;
219 bool _heap_region_special;
220 size_t _num_regions;
221 ShenandoahHeapRegion** _regions;
222 ShenandoahRegionIterator _update_refs_iterator;
223
224 public:
225
226 inline HeapWord* base() const { return _heap_region.start(); }
227
228 inline size_t num_regions() const { return _num_regions; }
229 inline bool is_heap_region_special() { return _heap_region_special; }
230
231 inline ShenandoahHeapRegion* const heap_region_containing(const void* addr) const;
232 inline size_t heap_region_index_containing(const void* addr) const;
233
234 inline ShenandoahHeapRegion* const get_region(size_t region_idx) const;
235
236 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
237 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
238
239 // ---------- GC state machinery
240 //
241 // GC state describes the important parts of collector state, that may be
242 // used to make barrier selection decisions in the native and generated code.
243 // Multiple bits can be set at once.
244 //
245 // Important invariant: when GC state is zero, the heap is stable, and no barriers
246 // are required.
247 //
248 public:
249 enum GCStateBitPos {
250 // Heap has forwarded objects: needs LRB barriers.
251 HAS_FORWARDED_BITPOS = 0,
252
253 // Heap is under marking: needs SATB barriers.
254 MARKING_BITPOS = 1,
255
256 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
257 EVACUATION_BITPOS = 2,
258
259 // Heap is under updating: needs no additional barriers.
260 UPDATEREFS_BITPOS = 3,
261 };
262
263 enum GCState {
264 STABLE = 0,
265 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
266 MARKING = 1 << MARKING_BITPOS,
267 EVACUATION = 1 << EVACUATION_BITPOS,
268 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
269 };
270
271 private:
272 ShenandoahSharedBitmap _gc_state;
273 ShenandoahSharedFlag _degenerated_gc_in_progress;
274 ShenandoahSharedFlag _full_gc_in_progress;
275 ShenandoahSharedFlag _full_gc_move_in_progress;
276 ShenandoahSharedFlag _progress_last_gc;
277 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
278 ShenandoahSharedFlag _concurrent_weak_root_in_progress;
279
280 void set_gc_state_all_threads(char state);
281 void set_gc_state_mask(uint mask, bool value);
282
283 public:
284 char gc_state() const;
285 static address gc_state_addr();
286
287 void set_concurrent_mark_in_progress(bool in_progress);
288 void set_evacuation_in_progress(bool in_progress);
289 void set_update_refs_in_progress(bool in_progress);
290 void set_degenerated_gc_in_progress(bool in_progress);
291 void set_full_gc_in_progress(bool in_progress);
292 void set_full_gc_move_in_progress(bool in_progress);
293 void set_has_forwarded_objects(bool cond);
294 void set_concurrent_strong_root_in_progress(bool cond);
295 void set_concurrent_weak_root_in_progress(bool cond);
296
297 inline bool is_stable() const;
298 inline bool is_idle() const;
299 inline bool is_concurrent_mark_in_progress() const;
300 inline bool is_update_refs_in_progress() const;
301 inline bool is_evacuation_in_progress() const;
302 inline bool is_degenerated_gc_in_progress() const;
303 inline bool is_full_gc_in_progress() const;
304 inline bool is_full_gc_move_in_progress() const;
305 inline bool has_forwarded_objects() const;
306 inline bool is_gc_in_progress_mask(uint mask) const;
307 inline bool is_stw_gc_in_progress() const;
308 inline bool is_concurrent_strong_root_in_progress() const;
309 inline bool is_concurrent_weak_root_in_progress() const;
310
311 // ---------- GC cancellation and degeneration machinery
312 //
313 // Cancelled GC flag is used to notify concurrent phases that they should terminate.
314 //
315 public:
316 enum ShenandoahDegenPoint {
317 _degenerated_unset,
318 _degenerated_outside_cycle,
319 _degenerated_mark,
320 _degenerated_evac,
321 _degenerated_updaterefs,
322 _DEGENERATED_LIMIT
323 };
324
325 static const char* degen_point_to_string(ShenandoahDegenPoint point) {
326 switch (point) {
327 case _degenerated_unset:
328 return "<UNSET>";
329 case _degenerated_outside_cycle:
330 return "Outside of Cycle";
331 case _degenerated_mark:
332 return "Mark";
333 case _degenerated_evac:
334 return "Evacuation";
335 case _degenerated_updaterefs:
336 return "Update Refs";
337 default:
338 ShouldNotReachHere();
339 return "ERROR";
340 }
341 };
342
343 private:
344 enum CancelState {
345 // Normal state. GC has not been cancelled and is open for cancellation.
346 // Worker threads can suspend for safepoint.
347 CANCELLABLE,
348
349 // GC has been cancelled. Worker threads can not suspend for
350 // safepoint but must finish their work as soon as possible.
351 CANCELLED,
352
353 // GC has not been cancelled and must not be cancelled. At least
354 // one worker thread checks for pending safepoint and may suspend
355 // if a safepoint is pending.
356 NOT_CANCELLED
357 };
358
359 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
360 bool try_cancel_gc();
361
362 public:
363 static address cancelled_gc_addr();
364
365 inline bool cancelled_gc() const;
366 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
367
368 inline void clear_cancelled_gc();
369
370 void cancel_gc(GCCause::Cause cause);
371
372 // ---------- GC operations entry points
373 //
374 public:
375 // Entry points to STW GC operations, these cause a related safepoint, that then
376 // call the entry method below
377 void vmop_entry_init_mark();
378 void vmop_entry_final_mark();
379 void vmop_entry_init_updaterefs();
380 void vmop_entry_final_updaterefs();
381 void vmop_entry_full(GCCause::Cause cause);
382 void vmop_degenerated(ShenandoahDegenPoint point);
383
384 // Entry methods to normally STW GC operations. These set up logging, monitoring
385 // and workers for net VM operation
386 void entry_init_mark();
387 void entry_final_mark();
388 void entry_init_updaterefs();
389 void entry_final_updaterefs();
390 void entry_full(GCCause::Cause cause);
391 void entry_degenerated(int point);
392
393 // Entry methods to normally concurrent GC operations. These set up logging, monitoring
394 // for concurrent operation.
395 void entry_reset();
396 void entry_mark();
397 void entry_preclean();
398 void entry_weak_roots();
399 void entry_class_unloading();
400 void entry_strong_roots();
401 void entry_cleanup_early();
402 void entry_evac();
403 void entry_updaterefs();
404 void entry_cleanup_complete();
405 void entry_uncommit(double shrink_before);
406
407 private:
408 // Actual work for the phases
409 void op_init_mark();
410 void op_final_mark();
411 void op_init_updaterefs();
412 void op_final_updaterefs();
413 void op_full(GCCause::Cause cause);
414 void op_degenerated(ShenandoahDegenPoint point);
415 void op_degenerated_fail();
416 void op_degenerated_futile();
417
418 void op_reset();
419 void op_mark();
420 void op_preclean();
421 void op_weak_roots();
422 void op_class_unloading();
423 void op_strong_roots();
424 void op_cleanup_early();
425 void op_conc_evac();
426 void op_stw_evac();
427 void op_updaterefs();
428 void op_cleanup_complete();
429 void op_uncommit(double shrink_before);
430
431 // Messages for GC trace events, they have to be immortal for
432 // passing around the logging/tracing systems
433 const char* init_mark_event_message() const;
434 const char* final_mark_event_message() const;
435 const char* conc_mark_event_message() const;
436 const char* degen_event_message(ShenandoahDegenPoint point) const;
437
438 // ---------- GC subsystems
439 //
440 private:
441 ShenandoahControlThread* _control_thread;
442 ShenandoahCollectorPolicy* _shenandoah_policy;
443 ShenandoahMode* _gc_mode;
444 ShenandoahHeuristics* _heuristics;
445 ShenandoahFreeSet* _free_set;
446 ShenandoahConcurrentMark* _scm;
447 ShenandoahMarkCompact* _full_gc;
448 ShenandoahPacer* _pacer;
449 ShenandoahVerifier* _verifier;
450
451 ShenandoahPhaseTimings* _phase_timings;
452
453 ShenandoahControlThread* control_thread() { return _control_thread; }
454 ShenandoahMarkCompact* full_gc() { return _full_gc; }
455
456 public:
457 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
458 ShenandoahMode* mode() const { return _gc_mode; }
459 ShenandoahHeuristics* heuristics() const { return _heuristics; }
460 ShenandoahFreeSet* free_set() const { return _free_set; }
461 ShenandoahConcurrentMark* concurrent_mark() { return _scm; }
462 ShenandoahPacer* pacer() const { return _pacer; }
463
464 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
465
466 ShenandoahVerifier* verifier();
467
468 // ---------- VM subsystem bindings
469 //
470 private:
471 ShenandoahMonitoringSupport* _monitoring_support;
472 MemoryPool* _memory_pool;
473 GCMemoryManager _stw_memory_manager;
474 GCMemoryManager _cycle_memory_manager;
475 ConcurrentGCTimer* _gc_timer;
476 SoftRefPolicy _soft_ref_policy;
477
478 // For exporting to SA
479 int _log_min_obj_alignment_in_bytes;
480 public:
481 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
482 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
483 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
484 SoftRefPolicy* soft_ref_policy() { return &_soft_ref_policy; }
485
486 GrowableArray<GCMemoryManager*> memory_managers();
487 GrowableArray<MemoryPool*> memory_pools();
488 MemoryUsage memory_usage();
489 GCTracer* tracer();
490 ConcurrentGCTimer* gc_timer() const;
491
492 // ---------- Reference processing
493 //
494 private:
495 AlwaysTrueClosure _subject_to_discovery;
496 ReferenceProcessor* _ref_processor;
497 ShenandoahSharedFlag _process_references;
498 bool _ref_proc_mt_discovery;
499 bool _ref_proc_mt_processing;
500
501 void ref_processing_init();
502
503 public:
504 ReferenceProcessor* ref_processor() { return _ref_processor; }
505 bool ref_processor_mt_discovery() { return _ref_proc_mt_discovery; }
506 bool ref_processor_mt_processing() { return _ref_proc_mt_processing; }
507 void set_process_references(bool pr);
508 bool process_references() const;
509
510 // ---------- Class Unloading
511 //
512 private:
513 ShenandoahSharedFlag _unload_classes;
514 ShenandoahUnload _unloader;
515
516 public:
517 void set_unload_classes(bool uc);
518 bool unload_classes() const;
519
520 // Perform STW class unloading and weak root cleaning
521 void parallel_cleaning(bool full_gc);
522
523 private:
524 void stw_unload_classes(bool full_gc);
525 void stw_process_weak_roots(bool full_gc);
526
527 // Prepare concurrent root processing
528 void prepare_concurrent_roots();
529 // Prepare and finish concurrent unloading
530 void prepare_concurrent_unloading();
531 void finish_concurrent_unloading();
532
533 // ---------- Generic interface hooks
534 // Minor things that super-interface expects us to implement to play nice with
535 // the rest of runtime. Some of the things here are not required to be implemented,
536 // and can be stubbed out.
537 //
538 public:
539 AdaptiveSizePolicy* size_policy() shenandoah_not_implemented_return(NULL);
540 bool is_maximal_no_gc() const shenandoah_not_implemented_return(false);
541
542 bool is_in(const void* p) const;
543
544 MemRegion reserved_region() const { return _reserved; }
545 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
546
547 void collect(GCCause::Cause cause);
548 void do_full_collection(bool clear_all_soft_refs);
549
550 // Used for parsing heap during error printing
551 HeapWord* block_start(const void* addr) const;
552 bool block_is_obj(const HeapWord* addr) const;
553 bool print_location(outputStream* st, void* addr) const;
554
555 // Used for native heap walkers: heap dumpers, mostly
556 void object_iterate(ObjectClosure* cl);
557
558 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
559 void keep_alive(oop obj);
560
561 // Used by RMI
562 jlong millis_since_last_gc();
563
564 // ---------- Safepoint interface hooks
565 //
566 public:
567 void safepoint_synchronize_begin();
568 void safepoint_synchronize_end();
569
570 // ---------- Code roots handling hooks
571 //
572 public:
573 void register_nmethod(nmethod* nm);
574 void unregister_nmethod(nmethod* nm);
575 void flush_nmethod(nmethod* nm);
576 void verify_nmethod(nmethod* nm) {}
577
578 // ---------- Pinning hooks
579 //
580 public:
581 // Shenandoah supports per-object (per-region) pinning
582 bool supports_object_pinning() const { return true; }
583
584 oop pin_object(JavaThread* thread, oop obj);
585 void unpin_object(JavaThread* thread, oop obj);
586
587 void sync_pinned_region_status();
588 void assert_pinned_region_status() NOT_DEBUG_RETURN;
589
590 // ---------- Allocation support
591 //
592 private:
593 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
594 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
595 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
596 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
597
598 public:
599 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
600 HeapWord* mem_allocate(size_t size, bool* what);
601 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
602 size_t size,
603 Metaspace::MetadataType mdtype);
604
605 void notify_mutator_alloc_words(size_t words, bool waste);
606
607 // Shenandoah supports TLAB allocation
608 bool supports_tlab_allocation() const { return true; }
609
610 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size);
611 size_t tlab_capacity(Thread *thr) const;
612 size_t unsafe_max_tlab_alloc(Thread *thread) const;
613 size_t max_tlab_size() const;
614 size_t tlab_used(Thread* ignored) const;
615
616 void ensure_parsability(bool retire_labs);
617
618 void labs_make_parsable();
619 void tlabs_retire(bool resize);
620 void gclabs_retire(bool resize);
621
622 // ---------- Marking support
623 //
624 private:
625 ShenandoahMarkingContext* _marking_context;
626 MemRegion _bitmap_region;
627 MemRegion _aux_bitmap_region;
628 MarkBitMap _verification_bit_map;
629 MarkBitMap _aux_bit_map;
630
631 size_t _bitmap_size;
632 size_t _bitmap_regions_per_slice;
633 size_t _bitmap_bytes_per_slice;
634
635 size_t _pretouch_heap_page_size;
636 size_t _pretouch_bitmap_page_size;
637
638 bool _bitmap_region_special;
639 bool _aux_bitmap_region_special;
640
641 ShenandoahLiveData** _liveness_cache;
642
643 public:
644 inline ShenandoahMarkingContext* complete_marking_context() const;
645 inline ShenandoahMarkingContext* marking_context() const;
646 inline void mark_complete_marking_context();
647 inline void mark_incomplete_marking_context();
648
649 template<class T>
650 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
651
652 template<class T>
653 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
654
655 template<class T>
656 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
657
658 void reset_mark_bitmap();
659
660 // SATB barriers hooks
661 inline bool requires_marking(const void* entry) const;
662 void force_satb_flush_all_threads();
663
664 // Support for bitmap uncommits
665 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
666 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
667 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
668
669 // Liveness caching support
670 ShenandoahLiveData* get_liveness_cache(uint worker_id);
671 void flush_liveness_cache(uint worker_id);
672
673 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
674
675 // ---------- Evacuation support
676 //
677 private:
678 ShenandoahCollectionSet* _collection_set;
679 ShenandoahEvacOOMHandler _oom_evac_handler;
680
681 void evacuate_and_update_roots();
682
683 public:
684 static address in_cset_fast_test_addr();
685
686 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
687
688 // Checks if object is in the collection set.
689 inline bool in_collection_set(oop obj) const;
690
691 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
692 inline bool in_collection_set_loc(void* loc) const;
693
694 // Evacuates object src. Returns the evacuated object, either evacuated
695 // by this thread, or by some other thread.
696 inline oop evacuate_object(oop src, Thread* thread);
697
698 // Call before/after evacuation.
699 inline void enter_evacuation(Thread* t);
700 inline void leave_evacuation(Thread* t);
701
702 // ---------- Helper functions
703 //
704 public:
705 template <class T>
706 inline oop evac_update_with_forwarded(T* p);
707
708 template <class T>
709 inline oop maybe_update_with_forwarded(T* p);
710
711 template <class T>
712 inline oop maybe_update_with_forwarded_not_null(T* p, oop obj);
713
714 template <class T>
715 inline oop update_with_forwarded_not_null(T* p, oop obj);
716
717 static inline oop cas_oop(oop n, narrowOop* addr, oop c);
718 static inline oop cas_oop(oop n, oop* addr, oop c);
719 static inline oop cas_oop(oop n, narrowOop* addr, narrowOop c);
720
721 void trash_humongous_region_at(ShenandoahHeapRegion *r);
722
723 void deduplicate_string(oop str);
724
725 private:
726 void trash_cset_regions();
727 void update_heap_references(bool concurrent);
728
729 // ---------- Testing helpers functions
730 //
731 private:
732 ShenandoahSharedFlag _inject_alloc_failure;
733
734 void try_inject_alloc_failure();
735 bool should_inject_alloc_failure();
736 };
737
738 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP