1 /*
2 * Copyright (c) 2013, 2019, 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_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
25 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
26
27 #include "gc/shared/markBitMap.hpp"
28 #include "gc/shared/softRefPolicy.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shenandoah/shenandoahAsserts.hpp"
31 #include "gc/shenandoah/shenandoahAllocRequest.hpp"
32 #include "gc/shenandoah/shenandoahHeapLock.hpp"
33 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
34 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
35 #include "services/memoryManager.hpp"
36
37 class ConcurrentGCTimer;
38 class ReferenceProcessor;
39 class ShenandoahAllocTracker;
40 class ShenandoahCollectorPolicy;
41 class ShenandoahControlThread;
42 class ShenandoahGCSession;
43 class ShenandoahHeuristics;
44 class ShenandoahMarkingContext;
45 class ShenandoahPhaseTimings;
46 class ShenandoahHeap;
47 class ShenandoahHeapRegion;
48 class ShenandoahHeapRegionClosure;
49 class ShenandoahCollectionSet;
50 class ShenandoahFreeSet;
51 class ShenandoahConcurrentMark;
52 class ShenandoahMarkCompact;
53 class ShenandoahMonitoringSupport;
54 class ShenandoahPacer;
55 class ShenandoahTraversalGC;
56 class ShenandoahVerifier;
57 class ShenandoahWorkGang;
58 class VMStructs;
59
60 class ShenandoahRegionIterator : public StackObj {
61 private:
62 ShenandoahHeap* _heap;
63
64 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
65 volatile size_t _index;
66 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
67
68 // No implicit copying: iterators should be passed by reference to capture the state
69 ShenandoahRegionIterator(const ShenandoahRegionIterator& that);
70 ShenandoahRegionIterator& operator=(const ShenandoahRegionIterator& o);
71
72 public:
73 ShenandoahRegionIterator();
74 ShenandoahRegionIterator(ShenandoahHeap* heap);
75
76 // Reset iterator to default state
77 void reset();
78
79 // Returns next region, or NULL if there are no more regions.
80 // This is multi-thread-safe.
81 inline ShenandoahHeapRegion* next();
82
83 // This is *not* MT safe. However, in the absence of multithreaded access, it
84 // can be used to determine if there is more work to do.
85 bool has_next() const;
86 };
87
88 class ShenandoahHeapRegionClosure : public StackObj {
89 public:
90 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
91 virtual bool is_thread_safe() { return false; }
92 };
93
94 #ifdef ASSERT
95 class ShenandoahAssertToSpaceClosure : public OopClosure {
96 private:
97 template <class T>
98 void do_oop_work(T* p);
99 public:
100 void do_oop(narrowOop* p);
101 void do_oop(oop* p);
102 };
103 #endif
104
105
106 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
107 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
108 // See ShenandoahControlThread for GC cycle structure.
109 //
110 class ShenandoahHeap : public CollectedHeap {
111 friend class ShenandoahAsserts;
112 friend class VMStructs;
113 friend class ShenandoahGCSession;
114
115 // ---------- Locks that guard important data structures in Heap
116 //
117 private:
118 ShenandoahHeapLock _lock;
119
120 public:
121 ShenandoahHeapLock* lock() {
122 return &_lock;
123 }
124
125 void assert_heaplock_owned_by_current_thread() NOT_DEBUG_RETURN;
126 void assert_heaplock_not_owned_by_current_thread() NOT_DEBUG_RETURN;
127 void assert_heaplock_or_safepoint() NOT_DEBUG_RETURN;
128
129 // ---------- Initialization, termination, identification, printing routines
130 //
131 public:
132 static ShenandoahHeap* heap();
133 static ShenandoahHeap* heap_no_check();
134
135 const char* name() const { return "Shenandoah"; }
136 ShenandoahHeap::Name kind() const { return CollectedHeap::Shenandoah; }
137
138 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
139 jint initialize();
140 void post_initialize();
141 void initialize_heuristics();
142
143 void initialize_serviceability();
144
145 void print_on(outputStream* st) const;
146 void print_extended_on(outputStream *st) const;
147 void print_tracing_info() const;
148 void print_gc_threads_on(outputStream* st) const;
149 void print_heap_regions_on(outputStream* st) const;
150
151 void stop();
152
153 void prepare_for_verify();
154 void verify(VerifyOption vo);
155
156 // ---------- Heap counters and metrics
157 //
158 private:
159 size_t _initial_size;
160 size_t _minimum_size;
161 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
162 volatile size_t _used;
163 volatile size_t _committed;
164 volatile size_t _bytes_allocated_since_gc_start;
165 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
166
167 public:
168 void increase_used(size_t bytes);
169 void decrease_used(size_t bytes);
170 void set_used(size_t bytes);
171
172 void increase_committed(size_t bytes);
173 void decrease_committed(size_t bytes);
174 void increase_allocated(size_t bytes);
175
176 size_t bytes_allocated_since_gc_start();
177 void reset_bytes_allocated_since_gc_start();
178
179 size_t min_capacity() const;
180 size_t max_capacity() const;
181 size_t initial_capacity() const;
182 size_t capacity() const;
183 size_t used() const;
184 size_t committed() const;
185
186 // ---------- Workers handling
187 //
188 private:
189 uint _max_workers;
190 ShenandoahWorkGang* _workers;
191 ShenandoahWorkGang* _safepoint_workers;
192
193 public:
194 uint max_workers();
195 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
196
197 WorkGang* workers() const;
198 WorkGang* get_safepoint_workers();
199
200 void gc_threads_do(ThreadClosure* tcl) const;
201
202 // ---------- Heap regions handling machinery
203 //
204 private:
205 MemRegion _heap_region;
206 bool _heap_region_special;
207 size_t _num_regions;
208 ShenandoahHeapRegion** _regions;
209 ShenandoahRegionIterator _update_refs_iterator;
210
211 public:
212 inline size_t num_regions() const { return _num_regions; }
213 inline bool is_heap_region_special() { return _heap_region_special; }
214
215 inline ShenandoahHeapRegion* const heap_region_containing(const void* addr) const;
216 inline size_t heap_region_index_containing(const void* addr) const;
217
218 inline ShenandoahHeapRegion* const get_region(size_t region_idx) const;
219
220 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
221 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
222
223 // ---------- GC state machinery
224 //
225 // GC state describes the important parts of collector state, that may be
226 // used to make barrier selection decisions in the native and generated code.
227 // Multiple bits can be set at once.
228 //
229 // Important invariant: when GC state is zero, the heap is stable, and no barriers
230 // are required.
231 //
232 public:
233 enum GCStateBitPos {
234 // Heap has forwarded objects: needs LRB barriers.
235 HAS_FORWARDED_BITPOS = 0,
236
237 // Heap is under marking: needs SATB barriers.
238 MARKING_BITPOS = 1,
239
240 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
241 EVACUATION_BITPOS = 2,
242
243 // Heap is under updating: needs no additional barriers.
244 UPDATEREFS_BITPOS = 3,
245
246 // Heap is under traversal collection
247 TRAVERSAL_BITPOS = 4,
248 };
249
250 enum GCState {
251 STABLE = 0,
252 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
253 MARKING = 1 << MARKING_BITPOS,
254 EVACUATION = 1 << EVACUATION_BITPOS,
255 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
256 TRAVERSAL = 1 << TRAVERSAL_BITPOS,
257 };
258
259 private:
260 ShenandoahSharedBitmap _gc_state;
261 ShenandoahSharedFlag _degenerated_gc_in_progress;
262 ShenandoahSharedFlag _full_gc_in_progress;
263 ShenandoahSharedFlag _full_gc_move_in_progress;
264 ShenandoahSharedFlag _progress_last_gc;
265
266 void set_gc_state_all_threads(char state);
267 void set_gc_state_mask(uint mask, bool value);
268
269 public:
270 char gc_state() const;
271 static address gc_state_addr();
272
273 void set_concurrent_mark_in_progress(bool in_progress);
274 void set_evacuation_in_progress(bool in_progress);
275 void set_update_refs_in_progress(bool in_progress);
276 void set_degenerated_gc_in_progress(bool in_progress);
277 void set_full_gc_in_progress(bool in_progress);
278 void set_full_gc_move_in_progress(bool in_progress);
279 void set_concurrent_traversal_in_progress(bool in_progress);
280 void set_has_forwarded_objects(bool cond);
281
282 inline bool is_stable() const;
283 inline bool is_idle() const;
284 inline bool is_concurrent_mark_in_progress() const;
285 inline bool is_update_refs_in_progress() const;
286 inline bool is_evacuation_in_progress() const;
287 inline bool is_degenerated_gc_in_progress() const;
288 inline bool is_full_gc_in_progress() const;
289 inline bool is_full_gc_move_in_progress() const;
290 inline bool is_concurrent_traversal_in_progress() const;
291 inline bool has_forwarded_objects() const;
292 inline bool is_gc_in_progress_mask(uint mask) const;
293
294 // ---------- GC cancellation and degeneration machinery
295 //
296 // Cancelled GC flag is used to notify concurrent phases that they should terminate.
297 //
298 public:
299 enum ShenandoahDegenPoint {
300 _degenerated_unset,
301 _degenerated_traversal,
302 _degenerated_outside_cycle,
303 _degenerated_mark,
304 _degenerated_evac,
305 _degenerated_updaterefs,
306 _DEGENERATED_LIMIT,
307 };
308
309 static const char* degen_point_to_string(ShenandoahDegenPoint point) {
310 switch (point) {
311 case _degenerated_unset:
312 return "<UNSET>";
313 case _degenerated_traversal:
314 return "Traversal";
315 case _degenerated_outside_cycle:
316 return "Outside of Cycle";
317 case _degenerated_mark:
318 return "Mark";
319 case _degenerated_evac:
320 return "Evacuation";
321 case _degenerated_updaterefs:
322 return "Update Refs";
323 default:
324 ShouldNotReachHere();
325 return "ERROR";
326 }
327 };
328
329 private:
330 enum CancelState {
331 // Normal state. GC has not been cancelled and is open for cancellation.
332 // Worker threads can suspend for safepoint.
333 CANCELLABLE,
334
335 // GC has been cancelled. Worker threads can not suspend for
336 // safepoint but must finish their work as soon as possible.
337 CANCELLED,
338
339 // GC has not been cancelled and must not be cancelled. At least
340 // one worker thread checks for pending safepoint and may suspend
341 // if a safepoint is pending.
342 NOT_CANCELLED
343 };
344
345 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
346 bool try_cancel_gc();
347
348 public:
349 static address cancelled_gc_addr();
350
351 inline bool cancelled_gc() const;
352 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
353
354 inline void clear_cancelled_gc();
355
356 void cancel_gc(GCCause::Cause cause);
357
358 // ---------- GC operations entry points
359 //
360 public:
361 // Entry points to STW GC operations, these cause a related safepoint, that then
362 // call the entry method below
363 void vmop_entry_init_mark();
364 void vmop_entry_final_mark();
365 void vmop_entry_final_evac();
366 void vmop_entry_init_updaterefs();
367 void vmop_entry_final_updaterefs();
368 void vmop_entry_init_traversal();
369 void vmop_entry_final_traversal();
370 void vmop_entry_full(GCCause::Cause cause);
371 void vmop_degenerated(ShenandoahDegenPoint point);
372
373 // Entry methods to normally STW GC operations. These set up logging, monitoring
374 // and workers for net VM operation
375 void entry_init_mark();
376 void entry_final_mark();
377 void entry_final_evac();
378 void entry_init_updaterefs();
379 void entry_final_updaterefs();
380 void entry_init_traversal();
381 void entry_final_traversal();
382 void entry_full(GCCause::Cause cause);
383 void entry_degenerated(int point);
384
385 // Entry methods to normally concurrent GC operations. These set up logging, monitoring
386 // for concurrent operation.
387 void entry_reset();
388 void entry_mark();
389 void entry_preclean();
390 void entry_cleanup();
391 void entry_evac();
392 void entry_updaterefs();
393 void entry_traversal();
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_init_traversal();
404 void op_final_traversal();
405 void op_full(GCCause::Cause cause);
406 void op_degenerated(ShenandoahDegenPoint point);
407 void op_degenerated_fail();
408 void op_degenerated_futile();
409
410 void op_reset();
411 void op_mark();
412 void op_preclean();
413 void op_cleanup();
414 void op_conc_evac();
415 void op_stw_evac();
416 void op_updaterefs();
417 void op_traversal();
418 void op_uncommit(double shrink_before);
419
420 // Messages for GC trace events, they have to be immortal for
421 // passing around the logging/tracing systems
422 const char* init_mark_event_message() const;
423 const char* final_mark_event_message() const;
424 const char* conc_mark_event_message() const;
425 const char* degen_event_message(ShenandoahDegenPoint point) const;
426
427 // ---------- GC subsystems
428 //
429 private:
430 ShenandoahControlThread* _control_thread;
431 ShenandoahCollectorPolicy* _shenandoah_policy;
432 ShenandoahHeuristics* _heuristics;
433 ShenandoahFreeSet* _free_set;
434 ShenandoahConcurrentMark* _scm;
435 ShenandoahTraversalGC* _traversal_gc;
436 ShenandoahMarkCompact* _full_gc;
437 ShenandoahPacer* _pacer;
438 ShenandoahVerifier* _verifier;
439
440 ShenandoahAllocTracker* _alloc_tracker;
441 ShenandoahPhaseTimings* _phase_timings;
442
443 ShenandoahControlThread* control_thread() { return _control_thread; }
444 ShenandoahMarkCompact* full_gc() { return _full_gc; }
445
446 public:
447 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
448 ShenandoahHeuristics* heuristics() const { return _heuristics; }
449 ShenandoahFreeSet* free_set() const { return _free_set; }
450 ShenandoahConcurrentMark* concurrent_mark() { return _scm; }
451 ShenandoahTraversalGC* traversal_gc() { return _traversal_gc; }
452 ShenandoahPacer* pacer() const { return _pacer; }
453
454 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
455 ShenandoahAllocTracker* alloc_tracker() const { return _alloc_tracker; }
456
457 ShenandoahVerifier* verifier();
458
459 // ---------- VM subsystem bindings
460 //
461 private:
462 ShenandoahMonitoringSupport* _monitoring_support;
463 MemoryPool* _memory_pool;
464 GCMemoryManager _stw_memory_manager;
465 GCMemoryManager _cycle_memory_manager;
466 ConcurrentGCTimer* _gc_timer;
467 SoftRefPolicy _soft_ref_policy;
468
469 // For exporting to SA
470 int _log_min_obj_alignment_in_bytes;
471 public:
472 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
473 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
474 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
475 SoftRefPolicy* soft_ref_policy() { return &_soft_ref_policy; }
476
477 GrowableArray<GCMemoryManager*> memory_managers();
478 GrowableArray<MemoryPool*> memory_pools();
479 MemoryUsage memory_usage();
480 GCTracer* tracer();
481 GCTimer* gc_timer() const;
482 CollectorPolicy* collector_policy() const;
483
484 // ---------- Reference processing
485 //
486 private:
487 AlwaysTrueClosure _subject_to_discovery;
488 ReferenceProcessor* _ref_processor;
489 ShenandoahSharedFlag _process_references;
490
491 void ref_processing_init();
492
493 public:
494 ReferenceProcessor* ref_processor() { return _ref_processor; }
495 void set_process_references(bool pr);
496 bool process_references() const;
497
498 // ---------- Class Unloading
499 //
500 private:
501 ShenandoahSharedFlag _unload_classes;
502
503 public:
504 void set_unload_classes(bool uc);
505 bool unload_classes() const;
506
507 // Delete entries for dead interned string and clean up unreferenced symbols
508 // in symbol table, possibly in parallel.
509 void unload_classes_and_cleanup_tables(bool full_gc);
510
511 // ---------- Generic interface hooks
512 // Minor things that super-interface expects us to implement to play nice with
513 // the rest of runtime. Some of the things here are not required to be implemented,
514 // and can be stubbed out.
515 //
516 public:
517 AdaptiveSizePolicy* size_policy() shenandoah_not_implemented_return(NULL);
518 bool is_maximal_no_gc() const shenandoah_not_implemented_return(false);
519
520 bool is_in(const void* p) const;
521
522 size_t obj_size(oop obj) const;
523 virtual ptrdiff_t cell_header_size() const;
524
525 void collect(GCCause::Cause cause);
526 void do_full_collection(bool clear_all_soft_refs);
527
528 // Used for parsing heap during error printing
529 HeapWord* block_start(const void* addr) const;
530 bool block_is_obj(const HeapWord* addr) const;
531
532 // Used for native heap walkers: heap dumpers, mostly
533 void object_iterate(ObjectClosure* cl);
534 void safe_object_iterate(ObjectClosure* cl);
535
536 // Used by RMI
537 jlong millis_since_last_gc();
538
539 // ---------- Safepoint interface hooks
540 //
541 public:
542 void safepoint_synchronize_begin();
543 void safepoint_synchronize_end();
544
545 // ---------- Code roots handling hooks
546 //
547 public:
548 void register_nmethod(nmethod* nm);
549 void unregister_nmethod(nmethod* nm);
550 void flush_nmethod(nmethod* nm) {}
551 void verify_nmethod(nmethod* nm) {}
552
553 // ---------- Pinning hooks
554 //
555 public:
556 // Shenandoah supports per-object (per-region) pinning
557 bool supports_object_pinning() const { return true; }
558
559 oop pin_object(JavaThread* thread, oop obj);
560 void unpin_object(JavaThread* thread, oop obj);
561
562 // ---------- Allocation support
563 //
564 private:
565 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
566 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
567 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
568 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
569 void retire_and_reset_gclabs();
570
571 public:
572 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
573 HeapWord* mem_allocate(size_t size, bool* what);
574 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
575 size_t size,
576 Metaspace::MetadataType mdtype);
577
578 oop obj_allocate(Klass* klass, int size, TRAPS);
579 oop array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS);
580 oop class_allocate(Klass* klass, int size, TRAPS);
581
582 void notify_mutator_alloc_words(size_t words, bool waste);
583
584 // Shenandoah supports TLAB allocation
585 bool supports_tlab_allocation() const { return true; }
586
587 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size);
588 size_t tlab_capacity(Thread *thr) const;
589 size_t unsafe_max_tlab_alloc(Thread *thread) const;
590 size_t max_tlab_size() const;
591 size_t tlab_used(Thread* ignored) const;
592
593 HeapWord* tlab_post_allocation_setup(HeapWord* obj);
594 void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap);
595 size_t min_dummy_object_size() const;
596
597 void resize_tlabs();
598
599 void ensure_parsability(bool retire_tlabs);
600 void make_parsable(bool retire_tlabs);
601
602 // ---------- Marking support
603 //
604 private:
605 ShenandoahMarkingContext* _marking_context;
606 MemRegion _bitmap_region;
607 MemRegion _aux_bitmap_region;
608 MarkBitMap _verification_bit_map;
609 MarkBitMap _aux_bit_map;
610
611 size_t _bitmap_size;
612 size_t _bitmap_regions_per_slice;
613 size_t _bitmap_bytes_per_slice;
614
615 bool _bitmap_region_special;
616 bool _aux_bitmap_region_special;
617
618 // Used for buffering per-region liveness data.
619 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
620 //
621 // The array has max-workers elements, each of which is an array of
622 // jushort * max_regions. The choice of jushort is not accidental:
623 // there is a tradeoff between static/dynamic footprint that translates
624 // into cache pressure (which is already high during marking), and
625 // too many atomic updates. size_t/jint is too large, jbyte is too small.
626 jushort** _liveness_cache;
627
628 public:
629 inline ShenandoahMarkingContext* complete_marking_context() const;
630 inline ShenandoahMarkingContext* marking_context() const;
631 inline void mark_complete_marking_context();
632 inline void mark_incomplete_marking_context();
633
634 template<class T>
635 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
636
637 template<class T>
638 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
639
640 template<class T>
641 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
642
643 void reset_mark_bitmap();
644
645 // SATB barriers hooks
646 template<bool RESOLVE>
647 inline bool requires_marking(const void* entry) const;
648 void force_satb_flush_all_threads();
649
650 // Support for bitmap uncommits
651 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
652 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
653 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
654
655 // Liveness caching support
656 jushort* get_liveness_cache(uint worker_id);
657 void flush_liveness_cache(uint worker_id);
658
659 // ---------- Evacuation support
660 //
661 private:
662 ShenandoahCollectionSet* _collection_set;
663 ShenandoahEvacOOMHandler _oom_evac_handler;
664
665 void evacuate_and_update_roots();
666
667 public:
668 static address in_cset_fast_test_addr();
669
670 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
671
672 template <class T>
673 inline bool in_collection_set(T obj) const;
674
675 // Avoid accidentally calling the method above with ShenandoahHeapRegion*, which would be *wrong*.
676 inline bool in_collection_set(ShenandoahHeapRegion* r) shenandoah_not_implemented_return(false);
677
678 // Evacuates object src. Returns the evacuated object, either evacuated
679 // by this thread, or by some other thread.
680 inline oop evacuate_object(oop src, Thread* thread);
681
682 // Call before/after evacuation.
683 void enter_evacuation();
684 void leave_evacuation();
685
686 // ---------- Helper functions
687 //
688 public:
689 template <class T>
690 inline oop evac_update_with_forwarded(T* p);
691
692 template <class T>
693 inline oop maybe_update_with_forwarded(T* p);
694
695 template <class T>
696 inline oop maybe_update_with_forwarded_not_null(T* p, oop obj);
697
698 template <class T>
699 inline oop update_with_forwarded_not_null(T* p, oop obj);
700
701 inline oop atomic_compare_exchange_oop(oop n, narrowOop* addr, oop c);
702 inline oop atomic_compare_exchange_oop(oop n, oop* addr, oop c);
703
704 void trash_humongous_region_at(ShenandoahHeapRegion *r);
705
706 void deduplicate_string(oop str);
707
708 void stop_concurrent_marking();
709
710 private:
711 void trash_cset_regions();
712 void update_heap_references(bool concurrent);
713
714 // ---------- Testing helpers functions
715 //
716 private:
717 ShenandoahSharedFlag _inject_alloc_failure;
718
719 void try_inject_alloc_failure();
720 bool should_inject_alloc_failure();
721 };
722
723 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP