1 /*
2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2013, 2021, Red Hat, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
27 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
28
29 #include "gc/shared/markBitMap.hpp"
30 #include "gc/shared/softRefPolicy.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp"
33 #include "gc/shenandoah/shenandoahAsserts.hpp"
34 #include "gc/shenandoah/shenandoahAllocRequest.hpp"
35 #include "gc/shenandoah/shenandoahLock.hpp"
36 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
37 #include "gc/shenandoah/shenandoahPadding.hpp"
38 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
39 #include "gc/shenandoah/shenandoahUnload.hpp"
40 #include "memory/metaspace.hpp"
41 #include "services/memoryManager.hpp"
42 #include "utilities/globalDefinitions.hpp"
43 #include "utilities/stack.hpp"
44
45 class ConcurrentGCTimer;
46 class ObjectIterateScanRootClosure;
47 class ShenandoahCollectorPolicy;
48 class ShenandoahControlThread;
49 class ShenandoahGCSession;
50 class ShenandoahGCStateResetter;
51 class ShenandoahHeuristics;
52 class ShenandoahMarkingContext;
53 class ShenandoahMode;
54 class ShenandoahPhaseTimings;
55 class ShenandoahHeap;
56 class ShenandoahHeapRegion;
57 class ShenandoahHeapRegionClosure;
58 class ShenandoahCollectionSet;
59 class ShenandoahFreeSet;
60 class ShenandoahConcurrentMark;
61 class ShenandoahFullGC;
62 class ShenandoahMonitoringSupport;
63 class ShenandoahPacer;
64 class ShenandoahReferenceProcessor;
65 class ShenandoahVerifier;
66 class ShenandoahWorkerThreads;
67 class VMStructs;
68
69 // Used for buffering per-region liveness data.
70 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
71 // The ShenandoahHeap array has max-workers elements, each of which is an array of
72 // uint16_t * max_regions. The choice of uint16_t is not accidental:
73 // there is a tradeoff between static/dynamic footprint that translates
74 // into cache pressure (which is already high during marking), and
75 // too many atomic updates. uint32_t is too large, uint8_t is too small.
76 typedef uint16_t ShenandoahLiveData;
77 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1)
78
79 class ShenandoahRegionIterator : public StackObj {
80 private:
81 ShenandoahHeap* _heap;
82
92 ShenandoahRegionIterator(ShenandoahHeap* heap);
93
94 // Reset iterator to default state
95 void reset();
96
97 // Returns next region, or null if there are no more regions.
98 // This is multi-thread-safe.
99 inline ShenandoahHeapRegion* next();
100
101 // This is *not* MT safe. However, in the absence of multithreaded access, it
102 // can be used to determine if there is more work to do.
103 bool has_next() const;
104 };
105
106 class ShenandoahHeapRegionClosure : public StackObj {
107 public:
108 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
109 virtual bool is_thread_safe() { return false; }
110 };
111
112 typedef ShenandoahLock ShenandoahHeapLock;
113 typedef ShenandoahLocker ShenandoahHeapLocker;
114 typedef Stack<oop, mtGC> ShenandoahScanObjectStack;
115
116 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
117 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
118 // See ShenandoahControlThread for GC cycle structure.
119 //
120 class ShenandoahHeap : public CollectedHeap, public ShenandoahSpaceInfo {
121 friend class ShenandoahAsserts;
122 friend class VMStructs;
123 friend class ShenandoahGCSession;
124 friend class ShenandoahGCStateResetter;
125 friend class ShenandoahParallelObjectIterator;
126 friend class ShenandoahSafepoint;
127
128 // Supported GC
129 friend class ShenandoahConcurrentGC;
130 friend class ShenandoahDegenGC;
131 friend class ShenandoahFullGC;
132 friend class ShenandoahUnload;
133
134 // ---------- Locks that guard important data structures in Heap
135 //
136 private:
137 ShenandoahHeapLock _lock;
138
139 public:
140 ShenandoahHeapLock* lock() {
141 return &_lock;
142 }
143
144 // ---------- Initialization, termination, identification, printing routines
145 //
146 public:
147 static ShenandoahHeap* heap();
148
149 const char* name() const override { return "Shenandoah"; }
150 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; }
151
152 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
153 jint initialize() override;
154 void post_initialize() override;
155 void initialize_mode();
156 void initialize_heuristics();
157
158 void initialize_serviceability() override;
159
160 void print_on(outputStream* st) const override;
161 void print_extended_on(outputStream *st) const override;
162 void print_tracing_info() const override;
163 void print_heap_regions_on(outputStream* st) const;
164
165 void stop() override;
166
167 void prepare_for_verify() override;
168 void verify(VerifyOption vo) override;
169
170 // WhiteBox testing support.
171 bool supports_concurrent_gc_breakpoints() const override {
172 return true;
173 }
174
175 // ---------- Heap counters and metrics
176 //
177 private:
178 size_t _initial_size;
179 size_t _minimum_size;
180 volatile size_t _soft_max_size;
181 shenandoah_padding(0);
182 volatile size_t _used;
183 volatile size_t _committed;
184 volatile size_t _bytes_allocated_since_gc_start;
185 shenandoah_padding(1);
186
187 public:
188 void increase_used(size_t bytes);
189 void decrease_used(size_t bytes);
190 void set_used(size_t bytes);
191
192 void increase_committed(size_t bytes);
193 void decrease_committed(size_t bytes);
194 void increase_allocated(size_t bytes);
195
196 size_t bytes_allocated_since_gc_start() const override;
197 void reset_bytes_allocated_since_gc_start();
198
199 size_t min_capacity() const;
200 size_t max_capacity() const override;
201 size_t soft_max_capacity() const override;
202 size_t initial_capacity() const;
203 size_t capacity() const override;
204 size_t used() const override;
205 size_t committed() const;
206 size_t available() const override;
207
208 void set_soft_max_capacity(size_t v);
209
210 // ---------- Periodic Tasks
211 //
212 private:
213 void notify_heap_changed();
214
215 public:
216 void set_forced_counters_update(bool value);
217 void handle_force_counters_update();
218
219 // ---------- Workers handling
220 //
221 private:
222 uint _max_workers;
223 ShenandoahWorkerThreads* _workers;
224 ShenandoahWorkerThreads* _safepoint_workers;
225
226 public:
227 uint max_workers();
228 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
229
230 WorkerThreads* workers() const;
231 WorkerThreads* safepoint_workers() override;
232
233 void gc_threads_do(ThreadClosure* tcl) const override;
234
235 // ---------- Heap regions handling machinery
236 //
237 private:
238 MemRegion _heap_region;
239 bool _heap_region_special;
240 size_t _num_regions;
241 ShenandoahHeapRegion** _regions;
242 ShenandoahRegionIterator _update_refs_iterator;
243
244 public:
245
246 inline HeapWord* base() const { return _heap_region.start(); }
247
248 inline size_t num_regions() const { return _num_regions; }
249 inline bool is_heap_region_special() { return _heap_region_special; }
250
251 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const;
252 inline size_t heap_region_index_containing(const void* addr) const;
253
254 inline ShenandoahHeapRegion* get_region(size_t region_idx) const;
255
256 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
257 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
258
259 // ---------- GC state machinery
260 //
261 // GC state describes the important parts of collector state, that may be
262 // used to make barrier selection decisions in the native and generated code.
263 // Multiple bits can be set at once.
264 //
265 // Important invariant: when GC state is zero, the heap is stable, and no barriers
266 // are required.
267 //
268 public:
269 enum GCStateBitPos {
270 // Heap has forwarded objects: needs LRB barriers.
271 HAS_FORWARDED_BITPOS = 0,
272
273 // Heap is under marking: needs SATB barriers.
274 MARKING_BITPOS = 1,
275
276 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
277 EVACUATION_BITPOS = 2,
278
279 // Heap is under updating: needs no additional barriers.
280 UPDATEREFS_BITPOS = 3,
281
282 // Heap is under weak-reference/roots processing: needs weak-LRB barriers.
283 WEAK_ROOTS_BITPOS = 4,
284 };
285
286 enum GCState {
287 STABLE = 0,
288 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
289 MARKING = 1 << MARKING_BITPOS,
290 EVACUATION = 1 << EVACUATION_BITPOS,
291 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
292 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS,
293 };
294
295 private:
296 bool _gc_state_changed;
297 ShenandoahSharedBitmap _gc_state;
298
299 // tracks if new regions have been allocated or retired since last check
300 ShenandoahSharedFlag _heap_changed;
301 ShenandoahSharedFlag _degenerated_gc_in_progress;
302 ShenandoahSharedFlag _full_gc_in_progress;
303 ShenandoahSharedFlag _full_gc_move_in_progress;
304 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
305
306 size_t _gc_no_progress_count;
307
308 // This updates the singlular, global gc state. This must happen on a safepoint.
309 void set_gc_state(uint mask, bool value);
310
311 public:
312 char gc_state() const;
313
314 // This copies the global gc state into a thread local variable for java threads.
315 // It is primarily intended to support quick access at barriers.
316 void propagate_gc_state_to_java_threads();
317
318 // This is public to support assertions that the state hasn't been changed off of
319 // a safepoint and that any changes were propagated to java threads after the safepoint.
320 bool has_gc_state_changed() const { return _gc_state_changed; }
321
322 // Returns true if allocations have occurred in new regions or if regions have been
323 // uncommitted since the previous calls. This call will reset the flag to false.
324 bool has_changed() {
325 return _heap_changed.try_unset();
326 }
327
328 void set_concurrent_mark_in_progress(bool in_progress);
329 void set_evacuation_in_progress(bool in_progress);
330 void set_update_refs_in_progress(bool in_progress);
331 void set_degenerated_gc_in_progress(bool in_progress);
332 void set_full_gc_in_progress(bool in_progress);
333 void set_full_gc_move_in_progress(bool in_progress);
334 void set_has_forwarded_objects(bool cond);
335 void set_concurrent_strong_root_in_progress(bool cond);
336 void set_concurrent_weak_root_in_progress(bool cond);
337
338 inline bool is_stable() const;
339 inline bool is_idle() const;
340 inline bool is_concurrent_mark_in_progress() const;
341 inline bool is_update_refs_in_progress() const;
342 inline bool is_evacuation_in_progress() const;
343 inline bool is_degenerated_gc_in_progress() const;
344 inline bool is_full_gc_in_progress() const;
345 inline bool is_full_gc_move_in_progress() const;
346 inline bool has_forwarded_objects() const;
347
348 inline bool is_stw_gc_in_progress() const;
349 inline bool is_concurrent_strong_root_in_progress() const;
350 inline bool is_concurrent_weak_root_in_progress() const;
351
352 private:
353 enum CancelState {
354 // Normal state. GC has not been cancelled and is open for cancellation.
355 // Worker threads can suspend for safepoint.
356 CANCELLABLE,
357
358 // GC has been cancelled. Worker threads can not suspend for
359 // safepoint but must finish their work as soon as possible.
360 CANCELLED
361 };
362
363 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
364 bool try_cancel_gc();
365
366 public:
367
368 inline bool cancelled_gc() const;
369 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
370
371 inline void clear_cancelled_gc();
372
373 void cancel_gc(GCCause::Cause cause);
374
375 public:
376 // These will uncommit empty regions if heap::committed > shrink_until
377 // and there exists at least one region which was made empty before shrink_before.
378 void maybe_uncommit(double shrink_before, size_t shrink_until);
379 void op_uncommit(double shrink_before, size_t shrink_until);
380
381 // Returns true if the soft maximum heap has been changed using management APIs.
382 bool check_soft_max_changed();
383
384 private:
385 // GC support
386 // Reset bitmap, prepare regions for new GC cycle
387 void prepare_gc();
388 void prepare_regions_and_collection_set(bool concurrent);
389 // Evacuation
390 void evacuate_collection_set(bool concurrent);
391 // Concurrent root processing
392 void prepare_concurrent_roots();
393 void finish_concurrent_roots();
394 // Concurrent class unloading support
395 void do_class_unloading();
396 // Reference updating
397 void prepare_update_heap_references(bool concurrent);
398 void update_heap_references(bool concurrent);
399 // Final update region states
400 void update_heap_region_states(bool concurrent);
401 void rebuild_free_set(bool concurrent);
402
403 void rendezvous_threads();
404 void recycle_trash();
405 public:
406 void notify_gc_progress();
407 void notify_gc_no_progress();
408 size_t get_gc_no_progress_count() const;
409
410 //
411 // Mark support
412 private:
413 ShenandoahControlThread* _control_thread;
414 ShenandoahCollectorPolicy* _shenandoah_policy;
415 ShenandoahMode* _gc_mode;
416 ShenandoahHeuristics* _heuristics;
417 ShenandoahFreeSet* _free_set;
418 ShenandoahPacer* _pacer;
419 ShenandoahVerifier* _verifier;
420
421 ShenandoahPhaseTimings* _phase_timings;
422
423 ShenandoahControlThread* control_thread() { return _control_thread; }
424
425 public:
426 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
427 ShenandoahMode* mode() const { return _gc_mode; }
428 ShenandoahHeuristics* heuristics() const { return _heuristics; }
429 ShenandoahFreeSet* free_set() const { return _free_set; }
430 ShenandoahPacer* pacer() const { return _pacer; }
431
432 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
433
434 ShenandoahVerifier* verifier();
435
436 // ---------- VM subsystem bindings
437 //
438 private:
439 ShenandoahMonitoringSupport* _monitoring_support;
440 MemoryPool* _memory_pool;
441 GCMemoryManager _stw_memory_manager;
442 GCMemoryManager _cycle_memory_manager;
443 ConcurrentGCTimer* _gc_timer;
444 // For exporting to SA
445 int _log_min_obj_alignment_in_bytes;
446 public:
447 ShenandoahMonitoringSupport* monitoring_support() { return _monitoring_support; }
448 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
449 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
450
451 GrowableArray<GCMemoryManager*> memory_managers() override;
452 GrowableArray<MemoryPool*> memory_pools() override;
453 MemoryUsage memory_usage() override;
454 GCTracer* tracer();
455 ConcurrentGCTimer* gc_timer() const;
456
457 // ---------- Reference processing
458 //
459 private:
460 ShenandoahReferenceProcessor* const _ref_processor;
461
462 public:
463 ShenandoahReferenceProcessor* ref_processor() { return _ref_processor; }
464
465 // ---------- Class Unloading
466 //
467 private:
468 ShenandoahSharedFlag _unload_classes;
469 ShenandoahUnload _unloader;
470
471 public:
472 void set_unload_classes(bool uc);
473 bool unload_classes() const;
474
475 // Perform STW class unloading and weak root cleaning
476 void parallel_cleaning(bool full_gc);
477
478 private:
479 void stw_unload_classes(bool full_gc);
480 void stw_process_weak_roots(bool full_gc);
481 void stw_weak_refs(bool full_gc);
482
483 // Heap iteration support
484 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops);
485 bool prepare_aux_bitmap_for_iteration();
486 void reclaim_aux_bitmap_for_iteration();
487
488 // ---------- Generic interface hooks
489 // Minor things that super-interface expects us to implement to play nice with
490 // the rest of runtime. Some of the things here are not required to be implemented,
491 // and can be stubbed out.
492 //
493 public:
494 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false);
495
496 bool is_in(const void* p) const override;
497
498 bool requires_barriers(stackChunkOop obj) const override;
499
500 MemRegion reserved_region() const { return _reserved; }
501 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
502
503 void collect(GCCause::Cause cause) override;
504 void do_full_collection(bool clear_all_soft_refs) override;
505
506 // Used for parsing heap during error printing
507 HeapWord* block_start(const void* addr) const;
508 bool block_is_obj(const HeapWord* addr) const;
509 bool print_location(outputStream* st, void* addr) const override;
510
511 // Used for native heap walkers: heap dumpers, mostly
512 void object_iterate(ObjectClosure* cl) override;
513 // Parallel heap iteration support
514 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override;
515
516 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
530 void verify_nmethod(nmethod* nm) override {}
531
532 // ---------- Pinning hooks
533 //
534 public:
535 // Shenandoah supports per-object (per-region) pinning
536 void pin_object(JavaThread* thread, oop obj) override;
537 void unpin_object(JavaThread* thread, oop obj) override;
538
539 void sync_pinned_region_status();
540 void assert_pinned_region_status() NOT_DEBUG_RETURN;
541
542 // ---------- Concurrent Stack Processing support
543 //
544 public:
545 bool uses_stack_watermark_barrier() const override { return true; }
546
547 // ---------- Allocation support
548 //
549 private:
550 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
551 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
552 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
553 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
554
555 public:
556 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
557 HeapWord* mem_allocate(size_t size, bool* what) override;
558 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
559 size_t size,
560 Metaspace::MetadataType mdtype) override;
561
562 void notify_mutator_alloc_words(size_t words, bool waste);
563
564 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override;
565 size_t tlab_capacity(Thread *thr) const override;
566 size_t unsafe_max_tlab_alloc(Thread *thread) const override;
567 size_t max_tlab_size() const override;
568 size_t tlab_used(Thread* ignored) const override;
569
570 void ensure_parsability(bool retire_labs) override;
571
572 void labs_make_parsable();
573 void tlabs_retire(bool resize);
574 void gclabs_retire(bool resize);
575
576 // ---------- Marking support
577 //
578 private:
579 ShenandoahMarkingContext* _marking_context;
580 MemRegion _bitmap_region;
581 MemRegion _aux_bitmap_region;
582 MarkBitMap _verification_bit_map;
583 MarkBitMap _aux_bit_map;
584
585 size_t _bitmap_size;
586 size_t _bitmap_regions_per_slice;
587 size_t _bitmap_bytes_per_slice;
588
589 size_t _pretouch_heap_page_size;
590 size_t _pretouch_bitmap_page_size;
591
592 bool _bitmap_region_special;
593 bool _aux_bitmap_region_special;
594
595 ShenandoahLiveData** _liveness_cache;
596
597 public:
598 inline ShenandoahMarkingContext* complete_marking_context() const;
599 inline ShenandoahMarkingContext* marking_context() const;
600 inline void mark_complete_marking_context();
601 inline void mark_incomplete_marking_context();
602
603 template<class T>
604 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
605
606 template<class T>
607 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
608
609 template<class T>
610 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
611
612 void reset_mark_bitmap();
613
614 // SATB barriers hooks
615 inline bool requires_marking(const void* entry) const;
616
617 // Support for bitmap uncommits
618 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
619 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
620 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
621
622 // Liveness caching support
623 ShenandoahLiveData* get_liveness_cache(uint worker_id);
624 void flush_liveness_cache(uint worker_id);
625
626 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
627
628 // ---------- Evacuation support
629 //
630 private:
631 ShenandoahCollectionSet* _collection_set;
632 ShenandoahEvacOOMHandler _oom_evac_handler;
633
634 public:
635 static address in_cset_fast_test_addr();
636
637 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
638
639 // Checks if object is in the collection set.
640 inline bool in_collection_set(oop obj) const;
641
642 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
643 inline bool in_collection_set_loc(void* loc) const;
644
645 // Evacuates object src. Returns the evacuated object, either evacuated
646 // by this thread, or by some other thread.
647 inline oop evacuate_object(oop src, Thread* thread);
648
649 // Call before/after evacuation.
650 inline void enter_evacuation(Thread* t);
651 inline void leave_evacuation(Thread* t);
652
653 // ---------- Helper functions
654 //
655 public:
656 template <class T>
657 inline void conc_update_with_forwarded(T* p);
658
659 template <class T>
660 inline void update_with_forwarded(T* p);
661
662 static inline void atomic_update_oop(oop update, oop* addr, oop compare);
663 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare);
664 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare);
665
666 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare);
667 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare);
668 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare);
669
670 static inline void atomic_clear_oop( oop* addr, oop compare);
671 static inline void atomic_clear_oop(narrowOop* addr, oop compare);
672 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare);
673
674 void trash_humongous_region_at(ShenandoahHeapRegion *r);
675
676 private:
677 void trash_cset_regions();
678
679 // ---------- Testing helpers functions
680 //
681 private:
682 ShenandoahSharedFlag _inject_alloc_failure;
683
684 void try_inject_alloc_failure();
685 bool should_inject_alloc_failure();
686 };
687
688 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
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1 /*
2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2013, 2021, Red Hat, Inc. All rights reserved.
4 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
28 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
29
30 #include "gc/shared/ageTable.hpp"
31 #include "gc/shared/markBitMap.hpp"
32 #include "gc/shared/softRefPolicy.hpp"
33 #include "gc/shared/collectedHeap.hpp"
34 #include "gc/shenandoah/shenandoahAgeCensus.hpp"
35 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp"
36 #include "gc/shenandoah/shenandoahAsserts.hpp"
37 #include "gc/shenandoah/shenandoahAllocRequest.hpp"
38 #include "gc/shenandoah/shenandoahAsserts.hpp"
39 #include "gc/shenandoah/shenandoahController.hpp"
40 #include "gc/shenandoah/shenandoahLock.hpp"
41 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
42 #include "gc/shenandoah/shenandoahEvacTracker.hpp"
43 #include "gc/shenandoah/shenandoahGenerationType.hpp"
44 #include "gc/shenandoah/shenandoahMmuTracker.hpp"
45 #include "gc/shenandoah/shenandoahPadding.hpp"
46 #include "gc/shenandoah/shenandoahScanRemembered.hpp"
47 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
48 #include "gc/shenandoah/shenandoahUnload.hpp"
49 #include "memory/metaspace.hpp"
50 #include "services/memoryManager.hpp"
51 #include "utilities/globalDefinitions.hpp"
52 #include "utilities/stack.hpp"
53
54 class ConcurrentGCTimer;
55 class ObjectIterateScanRootClosure;
56 class PLAB;
57 class ShenandoahCollectorPolicy;
58 class ShenandoahRegulatorThread;
59 class ShenandoahGCSession;
60 class ShenandoahGCStateResetter;
61 class ShenandoahGeneration;
62 class ShenandoahYoungGeneration;
63 class ShenandoahOldGeneration;
64 class ShenandoahHeuristics;
65 class ShenandoahOldHeuristics;
66 class ShenandoahYoungHeuristics;
67 class ShenandoahMarkingContext;
68 class ShenandoahPhaseTimings;
69 class ShenandoahHeap;
70 class ShenandoahHeapRegion;
71 class ShenandoahHeapRegionClosure;
72 class ShenandoahCollectionSet;
73 class ShenandoahFreeSet;
74 class ShenandoahConcurrentMark;
75 class ShenandoahFullGC;
76 class ShenandoahMonitoringSupport;
77 class ShenandoahMode;
78 class ShenandoahPacer;
79 class ShenandoahReferenceProcessor;
80 class ShenandoahVerifier;
81 class ShenandoahWorkerThreads;
82 class VMStructs;
83
84 // Used for buffering per-region liveness data.
85 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
86 // The ShenandoahHeap array has max-workers elements, each of which is an array of
87 // uint16_t * max_regions. The choice of uint16_t is not accidental:
88 // there is a tradeoff between static/dynamic footprint that translates
89 // into cache pressure (which is already high during marking), and
90 // too many atomic updates. uint32_t is too large, uint8_t is too small.
91 typedef uint16_t ShenandoahLiveData;
92 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1)
93
94 class ShenandoahRegionIterator : public StackObj {
95 private:
96 ShenandoahHeap* _heap;
97
107 ShenandoahRegionIterator(ShenandoahHeap* heap);
108
109 // Reset iterator to default state
110 void reset();
111
112 // Returns next region, or null if there are no more regions.
113 // This is multi-thread-safe.
114 inline ShenandoahHeapRegion* next();
115
116 // This is *not* MT safe. However, in the absence of multithreaded access, it
117 // can be used to determine if there is more work to do.
118 bool has_next() const;
119 };
120
121 class ShenandoahHeapRegionClosure : public StackObj {
122 public:
123 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
124 virtual bool is_thread_safe() { return false; }
125 };
126
127 template<ShenandoahGenerationType GENERATION>
128 class ShenandoahGenerationRegionClosure : public ShenandoahHeapRegionClosure {
129 public:
130 explicit ShenandoahGenerationRegionClosure(ShenandoahHeapRegionClosure* cl) : _cl(cl) {}
131 void heap_region_do(ShenandoahHeapRegion* r);
132 virtual bool is_thread_safe() { return _cl->is_thread_safe(); }
133 private:
134 ShenandoahHeapRegionClosure* _cl;
135 };
136
137 typedef ShenandoahLock ShenandoahHeapLock;
138 typedef ShenandoahLocker ShenandoahHeapLocker;
139 typedef Stack<oop, mtGC> ShenandoahScanObjectStack;
140
141 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
142 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
143 // See ShenandoahControlThread for GC cycle structure.
144 //
145 class ShenandoahHeap : public CollectedHeap {
146 friend class ShenandoahAsserts;
147 friend class VMStructs;
148 friend class ShenandoahGCSession;
149 friend class ShenandoahGCStateResetter;
150 friend class ShenandoahParallelObjectIterator;
151 friend class ShenandoahSafepoint;
152
153 // Supported GC
154 friend class ShenandoahConcurrentGC;
155 friend class ShenandoahOldGC;
156 friend class ShenandoahDegenGC;
157 friend class ShenandoahFullGC;
158 friend class ShenandoahUnload;
159
160 // ---------- Locks that guard important data structures in Heap
161 //
162 private:
163 ShenandoahHeapLock _lock;
164 ShenandoahGeneration* _gc_generation;
165
166 public:
167 ShenandoahHeapLock* lock() {
168 return &_lock;
169 }
170
171 ShenandoahGeneration* active_generation() const {
172 // last or latest generation might be a better name here.
173 return _gc_generation;
174 }
175
176 void set_gc_generation(ShenandoahGeneration* generation) {
177 _gc_generation = generation;
178 }
179
180 ShenandoahHeuristics* heuristics();
181 ShenandoahOldHeuristics* old_heuristics();
182 ShenandoahYoungHeuristics* young_heuristics();
183
184 bool doing_mixed_evacuations();
185 bool is_old_bitmap_stable() const;
186 bool is_gc_generation_young() const;
187
188 // ---------- Initialization, termination, identification, printing routines
189 //
190 public:
191 static ShenandoahHeap* heap();
192
193 const char* name() const override { return "Shenandoah"; }
194 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; }
195
196 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
197 jint initialize() override;
198 void post_initialize() override;
199 void initialize_heuristics_generations();
200 virtual void print_init_logger() const;
201 void initialize_serviceability() override;
202
203 void print_on(outputStream* st) const override;
204 void print_extended_on(outputStream *st) const override;
205 void print_tracing_info() const override;
206 void print_heap_regions_on(outputStream* st) const;
207
208 void stop() override;
209
210 void prepare_for_verify() override;
211 void verify(VerifyOption vo) override;
212
213 bool verify_generation_usage(bool verify_old, size_t old_regions, size_t old_bytes, size_t old_waste,
214 bool verify_young, size_t young_regions, size_t young_bytes, size_t young_waste);
215
216 // WhiteBox testing support.
217 bool supports_concurrent_gc_breakpoints() const override {
218 return true;
219 }
220
221 // ---------- Heap counters and metrics
222 //
223 private:
224 size_t _initial_size;
225 size_t _minimum_size;
226
227 volatile size_t _soft_max_size;
228 shenandoah_padding(0);
229 volatile size_t _committed;
230 shenandoah_padding(1);
231
232 void increase_used(const ShenandoahAllocRequest& req);
233
234 public:
235 void increase_used(ShenandoahGeneration* generation, size_t bytes);
236 void decrease_used(ShenandoahGeneration* generation, size_t bytes);
237 void increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes);
238 void decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes);
239
240 void increase_committed(size_t bytes);
241 void decrease_committed(size_t bytes);
242
243 void reset_bytes_allocated_since_gc_start();
244
245 size_t min_capacity() const;
246 size_t max_capacity() const override;
247 size_t soft_max_capacity() const;
248 size_t initial_capacity() const;
249 size_t capacity() const override;
250 size_t used() const override;
251 size_t committed() const;
252
253 void set_soft_max_capacity(size_t v);
254
255 // ---------- Periodic Tasks
256 //
257 private:
258 void notify_heap_changed();
259
260 public:
261 void set_forced_counters_update(bool value);
262 void handle_force_counters_update();
263
264 // ---------- Workers handling
265 //
266 private:
267 uint _max_workers;
268 ShenandoahWorkerThreads* _workers;
269 ShenandoahWorkerThreads* _safepoint_workers;
270
271 virtual void initialize_controller();
272
273 public:
274 uint max_workers();
275 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
276
277 WorkerThreads* workers() const;
278 WorkerThreads* safepoint_workers() override;
279
280 void gc_threads_do(ThreadClosure* tcl) const override;
281
282 // ---------- Heap regions handling machinery
283 //
284 private:
285 MemRegion _heap_region;
286 bool _heap_region_special;
287 size_t _num_regions;
288 ShenandoahHeapRegion** _regions;
289 uint8_t* _affiliations; // Holds array of enum ShenandoahAffiliation, including FREE status in non-generational mode
290 ShenandoahRegionIterator _update_refs_iterator;
291
292 public:
293
294 inline HeapWord* base() const { return _heap_region.start(); }
295
296 inline size_t num_regions() const { return _num_regions; }
297 inline bool is_heap_region_special() { return _heap_region_special; }
298
299 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const;
300 inline size_t heap_region_index_containing(const void* addr) const;
301
302 inline ShenandoahHeapRegion* get_region(size_t region_idx) const;
303
304 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
305 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
306
307 inline ShenandoahMmuTracker* mmu_tracker() { return &_mmu_tracker; };
308
309 // ---------- GC state machinery
310 //
311 // GC state describes the important parts of collector state, that may be
312 // used to make barrier selection decisions in the native and generated code.
313 // Multiple bits can be set at once.
314 //
315 // Important invariant: when GC state is zero, the heap is stable, and no barriers
316 // are required.
317 //
318 public:
319 enum GCStateBitPos {
320 // Heap has forwarded objects: needs LRB barriers.
321 HAS_FORWARDED_BITPOS = 0,
322
323 // Heap is under marking: needs SATB barriers.
324 // For generational mode, it means either young or old marking, or both.
325 MARKING_BITPOS = 1,
326
327 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
328 EVACUATION_BITPOS = 2,
329
330 // Heap is under updating: needs no additional barriers.
331 UPDATEREFS_BITPOS = 3,
332
333 // Heap is under weak-reference/roots processing: needs weak-LRB barriers.
334 WEAK_ROOTS_BITPOS = 4,
335
336 // Young regions are under marking, need SATB barriers.
337 YOUNG_MARKING_BITPOS = 5,
338
339 // Old regions are under marking, need SATB barriers.
340 OLD_MARKING_BITPOS = 6
341 };
342
343 enum GCState {
344 STABLE = 0,
345 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
346 MARKING = 1 << MARKING_BITPOS,
347 EVACUATION = 1 << EVACUATION_BITPOS,
348 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
349 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS,
350 YOUNG_MARKING = 1 << YOUNG_MARKING_BITPOS,
351 OLD_MARKING = 1 << OLD_MARKING_BITPOS
352 };
353
354 private:
355 bool _gc_state_changed;
356 ShenandoahSharedBitmap _gc_state;
357 ShenandoahSharedFlag _heap_changed;
358 ShenandoahSharedFlag _degenerated_gc_in_progress;
359 ShenandoahSharedFlag _full_gc_in_progress;
360 ShenandoahSharedFlag _full_gc_move_in_progress;
361 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
362
363 size_t _gc_no_progress_count;
364
365 // This updates the singlular, global gc state. This must happen on a safepoint.
366 void set_gc_state(uint mask, bool value);
367
368 ShenandoahAgeCensus* _age_census; // Age census used for adapting tenuring threshold in generational mode
369
370 public:
371 char gc_state() const;
372
373 // This copies the global gc state into a thread local variable for java threads.
374 // It is primarily intended to support quick access at barriers.
375 void propagate_gc_state_to_java_threads();
376
377 // This is public to support assertions that the state hasn't been changed off of
378 // a safepoint and that any changes were propagated to java threads after the safepoint.
379 bool has_gc_state_changed() const { return _gc_state_changed; }
380
381 // Returns true if allocations have occurred in new regions or if regions have been
382 // uncommitted since the previous calls. This call will reset the flag to false.
383 bool has_changed() {
384 return _heap_changed.try_unset();
385 }
386
387 void set_concurrent_young_mark_in_progress(bool in_progress);
388 void set_concurrent_old_mark_in_progress(bool in_progress);
389 void set_evacuation_in_progress(bool in_progress);
390 void set_update_refs_in_progress(bool in_progress);
391 void set_degenerated_gc_in_progress(bool in_progress);
392 void set_full_gc_in_progress(bool in_progress);
393 void set_full_gc_move_in_progress(bool in_progress);
394 void set_has_forwarded_objects(bool cond);
395 void set_concurrent_strong_root_in_progress(bool cond);
396 void set_concurrent_weak_root_in_progress(bool cond);
397
398 void set_aging_cycle(bool cond);
399
400 inline bool is_stable() const;
401 inline bool is_idle() const;
402
403 inline bool is_concurrent_mark_in_progress() const;
404 inline bool is_concurrent_young_mark_in_progress() const;
405 inline bool is_concurrent_old_mark_in_progress() const;
406 inline bool is_update_refs_in_progress() const;
407 inline bool is_evacuation_in_progress() const;
408 inline bool is_degenerated_gc_in_progress() const;
409 inline bool is_full_gc_in_progress() const;
410 inline bool is_full_gc_move_in_progress() const;
411 inline bool has_forwarded_objects() const;
412
413 inline bool is_stw_gc_in_progress() const;
414 inline bool is_concurrent_strong_root_in_progress() const;
415 inline bool is_concurrent_weak_root_in_progress() const;
416 bool is_prepare_for_old_mark_in_progress() const;
417 inline bool is_aging_cycle() const;
418
419 // Return the age census object for young gen (in generational mode)
420 inline ShenandoahAgeCensus* age_census() const;
421
422 private:
423 void manage_satb_barrier(bool active);
424
425 enum CancelState {
426 // Normal state. GC has not been cancelled and is open for cancellation.
427 // Worker threads can suspend for safepoint.
428 CANCELLABLE,
429
430 // GC has been cancelled. Worker threads can not suspend for
431 // safepoint but must finish their work as soon as possible.
432 CANCELLED
433 };
434
435 double _cancel_requested_time;
436 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc;
437
438 // Returns true if cancel request was successfully communicated.
439 // Returns false if some other thread already communicated cancel
440 // request. A true return value does not mean GC has been
441 // cancelled, only that the process of cancelling GC has begun.
442 bool try_cancel_gc();
443
444 public:
445 inline bool cancelled_gc() const;
446 inline bool check_cancelled_gc_and_yield(bool sts_active = true);
447
448 inline void clear_cancelled_gc(bool clear_oom_handler = true);
449
450 void cancel_concurrent_mark();
451 void cancel_gc(GCCause::Cause cause);
452
453 public:
454 // These will uncommit empty regions if heap::committed > shrink_until
455 // and there exists at least one region which was made empty before shrink_before.
456 void maybe_uncommit(double shrink_before, size_t shrink_until);
457 void op_uncommit(double shrink_before, size_t shrink_until);
458
459 // Returns true if the soft maximum heap has been changed using management APIs.
460 bool check_soft_max_changed();
461
462 private:
463 // GC support
464 // Evacuation
465 void evacuate_collection_set(bool concurrent);
466 // Concurrent root processing
467 void prepare_concurrent_roots();
468 void finish_concurrent_roots();
469 // Concurrent class unloading support
470 void do_class_unloading();
471 // Reference updating
472 void prepare_update_heap_references(bool concurrent);
473 void update_heap_references(bool concurrent);
474 // Final update region states
475 void update_heap_region_states(bool concurrent);
476
477 void rendezvous_threads();
478 void recycle_trash();
479 public:
480 void rebuild_free_set(bool concurrent);
481 void notify_gc_progress();
482 void notify_gc_no_progress();
483 size_t get_gc_no_progress_count() const;
484
485 //
486 // Mark support
487 private:
488 ShenandoahYoungGeneration* _young_generation;
489 ShenandoahGeneration* _global_generation;
490 ShenandoahOldGeneration* _old_generation;
491
492 protected:
493 ShenandoahController* _control_thread;
494
495 private:
496 ShenandoahCollectorPolicy* _shenandoah_policy;
497 ShenandoahMode* _gc_mode;
498 ShenandoahFreeSet* _free_set;
499 ShenandoahPacer* _pacer;
500 ShenandoahVerifier* _verifier;
501
502 ShenandoahPhaseTimings* _phase_timings;
503 ShenandoahEvacuationTracker* _evac_tracker;
504 ShenandoahMmuTracker _mmu_tracker;
505 ShenandoahGenerationSizer _generation_sizer;
506
507 public:
508 ShenandoahController* control_thread() { return _control_thread; }
509
510 ShenandoahYoungGeneration* young_generation() const { return _young_generation; }
511 ShenandoahGeneration* global_generation() const { return _global_generation; }
512 ShenandoahOldGeneration* old_generation() const { return _old_generation; }
513 ShenandoahGeneration* generation_for(ShenandoahAffiliation affiliation) const;
514 const ShenandoahGenerationSizer* generation_sizer() const { return &_generation_sizer; }
515
516 size_t max_size_for(ShenandoahGeneration* generation) const;
517 size_t min_size_for(ShenandoahGeneration* generation) const;
518
519 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
520 ShenandoahMode* mode() const { return _gc_mode; }
521 ShenandoahFreeSet* free_set() const { return _free_set; }
522 ShenandoahPacer* pacer() const { return _pacer; }
523
524 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
525 ShenandoahEvacuationTracker* evac_tracker() const { return _evac_tracker; }
526
527 void on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation);
528 void on_cycle_end(ShenandoahGeneration* generation);
529
530 ShenandoahVerifier* verifier();
531
532 // ---------- VM subsystem bindings
533 //
534 private:
535 ShenandoahMonitoringSupport* _monitoring_support;
536 MemoryPool* _memory_pool;
537 GCMemoryManager _stw_memory_manager;
538 GCMemoryManager _cycle_memory_manager;
539 ConcurrentGCTimer* _gc_timer;
540 // For exporting to SA
541 int _log_min_obj_alignment_in_bytes;
542 public:
543 ShenandoahMonitoringSupport* monitoring_support() const { return _monitoring_support; }
544 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
545 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
546
547 GrowableArray<GCMemoryManager*> memory_managers() override;
548 GrowableArray<MemoryPool*> memory_pools() override;
549 MemoryUsage memory_usage() override;
550 GCTracer* tracer();
551 ConcurrentGCTimer* gc_timer() const;
552
553 // ---------- Class Unloading
554 //
555 private:
556 ShenandoahSharedFlag _is_aging_cycle;
557 ShenandoahSharedFlag _unload_classes;
558 ShenandoahUnload _unloader;
559
560 public:
561 void set_unload_classes(bool uc);
562 bool unload_classes() const;
563
564 // Perform STW class unloading and weak root cleaning
565 void parallel_cleaning(bool full_gc);
566
567 private:
568 void stw_unload_classes(bool full_gc);
569 void stw_process_weak_roots(bool full_gc);
570 void stw_weak_refs(bool full_gc);
571
572 inline void assert_lock_for_affiliation(ShenandoahAffiliation orig_affiliation,
573 ShenandoahAffiliation new_affiliation);
574
575 // Heap iteration support
576 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops);
577 bool prepare_aux_bitmap_for_iteration();
578 void reclaim_aux_bitmap_for_iteration();
579
580 // ---------- Generic interface hooks
581 // Minor things that super-interface expects us to implement to play nice with
582 // the rest of runtime. Some of the things here are not required to be implemented,
583 // and can be stubbed out.
584 //
585 public:
586 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false);
587
588 inline bool is_in(const void* p) const override;
589
590 inline bool is_in_active_generation(oop obj) const;
591 inline bool is_in_young(const void* p) const;
592 inline bool is_in_old(const void* p) const;
593 inline bool is_old(oop pobj) const;
594
595 inline ShenandoahAffiliation region_affiliation(const ShenandoahHeapRegion* r);
596 inline void set_affiliation(ShenandoahHeapRegion* r, ShenandoahAffiliation new_affiliation);
597
598 inline ShenandoahAffiliation region_affiliation(size_t index);
599
600 bool requires_barriers(stackChunkOop obj) const override;
601
602 MemRegion reserved_region() const { return _reserved; }
603 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
604
605 void collect(GCCause::Cause cause) override;
606 void do_full_collection(bool clear_all_soft_refs) override;
607
608 // Used for parsing heap during error printing
609 HeapWord* block_start(const void* addr) const;
610 bool block_is_obj(const HeapWord* addr) const;
611 bool print_location(outputStream* st, void* addr) const override;
612
613 // Used for native heap walkers: heap dumpers, mostly
614 void object_iterate(ObjectClosure* cl) override;
615 // Parallel heap iteration support
616 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override;
617
618 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
632 void verify_nmethod(nmethod* nm) override {}
633
634 // ---------- Pinning hooks
635 //
636 public:
637 // Shenandoah supports per-object (per-region) pinning
638 void pin_object(JavaThread* thread, oop obj) override;
639 void unpin_object(JavaThread* thread, oop obj) override;
640
641 void sync_pinned_region_status();
642 void assert_pinned_region_status() NOT_DEBUG_RETURN;
643
644 // ---------- Concurrent Stack Processing support
645 //
646 public:
647 bool uses_stack_watermark_barrier() const override { return true; }
648
649 // ---------- Allocation support
650 //
651 private:
652 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region, bool is_promotion);
653
654 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
655 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
656 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
657
658 inline HeapWord* allocate_from_plab(Thread* thread, size_t size, bool is_promotion);
659 HeapWord* allocate_from_plab_slow(Thread* thread, size_t size, bool is_promotion);
660 HeapWord* allocate_new_plab(size_t min_size, size_t word_size, size_t* actual_size);
661
662 public:
663 HeapWord* allocate_memory(ShenandoahAllocRequest& request, bool is_promotion);
664 HeapWord* mem_allocate(size_t size, bool* what) override;
665 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
666 size_t size,
667 Metaspace::MetadataType mdtype) override;
668
669 void notify_mutator_alloc_words(size_t words, size_t waste);
670
671 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override;
672 size_t tlab_capacity(Thread *thr) const override;
673 size_t unsafe_max_tlab_alloc(Thread *thread) const override;
674 size_t max_tlab_size() const override;
675 size_t tlab_used(Thread* ignored) const override;
676
677 void ensure_parsability(bool retire_labs) override;
678
679 void labs_make_parsable();
680 void tlabs_retire(bool resize);
681 void gclabs_retire(bool resize);
682
683 // ---------- Marking support
684 //
685 private:
686 ShenandoahMarkingContext* _marking_context;
687 MemRegion _bitmap_region;
688 MemRegion _aux_bitmap_region;
689 MarkBitMap _verification_bit_map;
690 MarkBitMap _aux_bit_map;
691
692 size_t _bitmap_size;
693 size_t _bitmap_regions_per_slice;
694 size_t _bitmap_bytes_per_slice;
695
696 size_t _pretouch_heap_page_size;
697 size_t _pretouch_bitmap_page_size;
698
699 bool _bitmap_region_special;
700 bool _aux_bitmap_region_special;
701
702 ShenandoahLiveData** _liveness_cache;
703
704 public:
705 inline ShenandoahMarkingContext* complete_marking_context() const;
706 inline ShenandoahMarkingContext* marking_context() const;
707
708 template<class T>
709 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
710
711 template<class T>
712 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
713
714 template<class T>
715 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
716
717 // SATB barriers hooks
718 inline bool requires_marking(const void* entry) const;
719
720 // Support for bitmap uncommits
721 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
722 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
723 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
724
725 // Liveness caching support
726 ShenandoahLiveData* get_liveness_cache(uint worker_id);
727 void flush_liveness_cache(uint worker_id);
728
729 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
730
731 // ---------- Evacuation support
732 //
733 private:
734 ShenandoahCollectionSet* _collection_set;
735 ShenandoahEvacOOMHandler _oom_evac_handler;
736
737 oop try_evacuate_object(oop src, Thread* thread, ShenandoahHeapRegion* from_region, ShenandoahAffiliation target_gen);
738 public:
739
740 static address in_cset_fast_test_addr();
741
742 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
743
744 // Checks if object is in the collection set.
745 inline bool in_collection_set(oop obj) const;
746
747 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
748 inline bool in_collection_set_loc(void* loc) const;
749
750 // Evacuates or promotes object src. Returns the evacuated object, either evacuated
751 // by this thread, or by some other thread.
752 inline oop evacuate_object(oop src, Thread* thread);
753
754 // Call before/after evacuation.
755 inline void enter_evacuation(Thread* t);
756 inline void leave_evacuation(Thread* t);
757
758 // ---------- Generational support
759 //
760 private:
761 RememberedScanner* _card_scan;
762
763 public:
764 inline RememberedScanner* card_scan() { return _card_scan; }
765 void clear_cards_for(ShenandoahHeapRegion* region);
766 void mark_card_as_dirty(void* location);
767 void retire_plab(PLAB* plab);
768 void retire_plab(PLAB* plab, Thread* thread);
769 void cancel_old_gc();
770
771 // ---------- Helper functions
772 //
773 public:
774 template <class T>
775 inline void conc_update_with_forwarded(T* p);
776
777 template <class T>
778 inline void update_with_forwarded(T* p);
779
780 static inline void atomic_update_oop(oop update, oop* addr, oop compare);
781 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare);
782 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare);
783
784 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare);
785 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare);
786 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare);
787
788 static inline void atomic_clear_oop( oop* addr, oop compare);
789 static inline void atomic_clear_oop(narrowOop* addr, oop compare);
790 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare);
791
792 size_t trash_humongous_region_at(ShenandoahHeapRegion *r);
793
794 static inline void increase_object_age(oop obj, uint additional_age);
795
796 // Return the object's age, or a sentinel value when the age can't
797 // necessarily be determined because of concurrent locking by the
798 // mutator
799 static inline uint get_object_age(oop obj);
800
801 void transfer_old_pointers_from_satb();
802
803 void log_heap_status(const char *msg) const;
804
805 private:
806 void trash_cset_regions();
807
808 // ---------- Testing helpers functions
809 //
810 private:
811 ShenandoahSharedFlag _inject_alloc_failure;
812
813 void try_inject_alloc_failure();
814 bool should_inject_alloc_failure();
815 };
816
817 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP
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