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