1 /*
2 * Copyright (c) 2023, 2024, 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
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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/shenandoahAllocRequest.hpp"
34 #include "gc/shenandoah/shenandoahAsserts.hpp"
35 #include "gc/shenandoah/shenandoahController.hpp"
36 #include "gc/shenandoah/shenandoahLock.hpp"
37 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
38 #include "gc/shenandoah/shenandoahEvacTracker.hpp"
39 #include "gc/shenandoah/shenandoahGenerationType.hpp"
40 #include "gc/shenandoah/shenandoahGenerationSizer.hpp"
41 #include "gc/shenandoah/shenandoahMmuTracker.hpp"
42 #include "gc/shenandoah/mode/shenandoahMode.hpp"
43 #include "gc/shenandoah/shenandoahPadding.hpp"
44 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
45 #include "gc/shenandoah/shenandoahUnload.hpp"
46 #include "memory/metaspace.hpp"
47 #include "services/memoryManager.hpp"
48 #include "utilities/globalDefinitions.hpp"
49 #include "utilities/stack.hpp"
50
51 class ConcurrentGCTimer;
52 class ObjectIterateScanRootClosure;
53 class ShenandoahCollectorPolicy;
54 class ShenandoahGCSession;
55 class ShenandoahGCStateResetter;
56 class ShenandoahGeneration;
57 class ShenandoahYoungGeneration;
58 class ShenandoahOldGeneration;
59 class ShenandoahHeuristics;
60 class ShenandoahMarkingContext;
61 class ShenandoahMode;
62 class ShenandoahPhaseTimings;
63 class ShenandoahHeap;
64 class ShenandoahHeapRegion;
65 class ShenandoahHeapRegionClosure;
66 class ShenandoahCollectionSet;
67 class ShenandoahFreeSet;
68 class ShenandoahConcurrentMark;
69 class ShenandoahFullGC;
70 class ShenandoahMonitoringSupport;
71 class ShenandoahPacer;
72 class ShenandoahReferenceProcessor;
73 class ShenandoahVerifier;
74 class ShenandoahWorkerThreads;
75 class VMStructs;
76
77 // Used for buffering per-region liveness data.
78 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
79 // The ShenandoahHeap array has max-workers elements, each of which is an array of
80 // uint16_t * max_regions. The choice of uint16_t is not accidental:
81 // there is a tradeoff between static/dynamic footprint that translates
82 // into cache pressure (which is already high during marking), and
83 // too many atomic updates. uint32_t is too large, uint8_t is too small.
84 typedef uint16_t ShenandoahLiveData;
85 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1)
86
87 class ShenandoahRegionIterator : public StackObj {
88 private:
89 ShenandoahHeap* _heap;
90
91 shenandoah_padding(0);
92 volatile size_t _index;
93 shenandoah_padding(1);
94
95 // No implicit copying: iterators should be passed by reference to capture the state
96 NONCOPYABLE(ShenandoahRegionIterator);
97
98 public:
99 ShenandoahRegionIterator();
100 ShenandoahRegionIterator(ShenandoahHeap* heap);
101
102 // Reset iterator to default state
103 void reset();
104
105 // Returns next region, or null if there are no more regions.
106 // This is multi-thread-safe.
107 inline ShenandoahHeapRegion* next();
108
109 // This is *not* MT safe. However, in the absence of multithreaded access, it
110 // can be used to determine if there is more work to do.
111 bool has_next() const;
112 };
113
114 class ShenandoahHeapRegionClosure : public StackObj {
115 public:
116 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0;
117 virtual bool is_thread_safe() { return false; }
118 };
119
120 typedef ShenandoahLock ShenandoahHeapLock;
121 typedef ShenandoahLocker ShenandoahHeapLocker;
122 typedef Stack<oop, mtGC> ShenandoahScanObjectStack;
123
124 class ShenandoahSynchronizePinnedRegionStates : public ShenandoahHeapRegionClosure {
125 private:
126 ShenandoahHeapLock* const _lock;
127
128 public:
129 ShenandoahSynchronizePinnedRegionStates();
130
131 void heap_region_do(ShenandoahHeapRegion* r) override;
132 bool is_thread_safe() override { return true; }
133 };
134
135 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers
136 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding.
137 // See ShenandoahControlThread for GC cycle structure.
138 //
139 class ShenandoahHeap : public CollectedHeap {
140 friend class ShenandoahAsserts;
141 friend class VMStructs;
142 friend class ShenandoahGCSession;
143 friend class ShenandoahGCStateResetter;
144 friend class ShenandoahParallelObjectIterator;
145 friend class ShenandoahSafepoint;
146
147 // Supported GC
148 friend class ShenandoahConcurrentGC;
149 friend class ShenandoahOldGC;
150 friend class ShenandoahDegenGC;
151 friend class ShenandoahFullGC;
152 friend class ShenandoahUnload;
153
154 // ---------- Locks that guard important data structures in Heap
155 //
156 private:
157 ShenandoahHeapLock _lock;
158
159 // Indicates the generation whose collection is in
160 // progress. Mutator threads aren't allowed to read
161 // this field.
162 ShenandoahGeneration* _gc_generation;
163
164 // This is set and cleared by only the VMThread
165 // at each STW pause (safepoint) to the value seen in
166 // _gc_generation. This allows the value to be always consistently
167 // seen by all mutators as well as all GC worker threads.
168 // In that sense, it's a stable snapshot of _gc_generation that is
169 // updated at each STW pause associated with a ShenandoahVMOp.
170 ShenandoahGeneration* _active_generation;
171
172 public:
173 ShenandoahHeapLock* lock() {
174 return &_lock;
175 }
176
177 ShenandoahGeneration* gc_generation() const {
178 // We don't want this field read by a mutator thread
179 assert(!Thread::current()->is_Java_thread(), "Not allowed");
180 // value of _gc_generation field, see above
181 return _gc_generation;
182 }
183
184 ShenandoahGeneration* active_generation() const {
185 // value of _active_generation field, see above
186 return _active_generation;
187 }
188
189 // Set the _gc_generation field
190 void set_gc_generation(ShenandoahGeneration* generation);
191
192 // Copy the value in the _gc_generation field into
193 // the _active_generation field: can only be called at
194 // a safepoint by the VMThread.
195 void set_active_generation();
196
197 ShenandoahHeuristics* heuristics();
198
199 // ---------- Initialization, termination, identification, printing routines
200 //
201 public:
202 static ShenandoahHeap* heap();
203
204 const char* name() const override { return "Shenandoah"; }
205 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; }
206
207 ShenandoahHeap(ShenandoahCollectorPolicy* policy);
208 jint initialize() override;
209 void post_initialize() override;
210 void initialize_mode();
211 virtual void initialize_heuristics();
212 virtual void print_init_logger() const;
213 void initialize_serviceability() override;
214
215 void print_on(outputStream* st) const override;
216 void print_extended_on(outputStream *st) const override;
217 void print_tracing_info() const override;
218 void print_heap_regions_on(outputStream* st) const;
219
220 void stop() override;
221
222 void prepare_for_verify() override;
223 void verify(VerifyOption vo) override;
224
225 // WhiteBox testing support.
226 bool supports_concurrent_gc_breakpoints() const override {
227 return true;
228 }
229
230 // ---------- Heap counters and metrics
231 //
232 private:
233 size_t _initial_size;
234 size_t _minimum_size;
235
236 volatile size_t _soft_max_size;
237 shenandoah_padding(0);
238 volatile size_t _committed;
239 shenandoah_padding(1);
240
241 void increase_used(const ShenandoahAllocRequest& req);
242
243 public:
244 void increase_used(ShenandoahGeneration* generation, size_t bytes);
245 void decrease_used(ShenandoahGeneration* generation, size_t bytes);
246 void increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes);
247 void decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes);
248
249 void increase_committed(size_t bytes);
250 void decrease_committed(size_t bytes);
251
252 void reset_bytes_allocated_since_gc_start();
253
254 size_t min_capacity() const;
255 size_t max_capacity() const override;
256 size_t soft_max_capacity() const;
257 size_t initial_capacity() const;
258 size_t capacity() const override;
259 size_t used() const override;
260 size_t committed() const;
261
262 void set_soft_max_capacity(size_t v);
263
264 // ---------- Periodic Tasks
265 //
266 private:
267 void notify_heap_changed();
268
269 public:
270 void set_forced_counters_update(bool value);
271 void handle_force_counters_update();
272
273 // ---------- Workers handling
274 //
275 private:
276 uint _max_workers;
277 ShenandoahWorkerThreads* _workers;
278 ShenandoahWorkerThreads* _safepoint_workers;
279
280 virtual void initialize_controller();
281
282 public:
283 uint max_workers();
284 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN;
285
286 WorkerThreads* workers() const;
287 WorkerThreads* safepoint_workers() override;
288
289 void gc_threads_do(ThreadClosure* tcl) const override;
290
291 // ---------- Heap regions handling machinery
292 //
293 private:
294 MemRegion _heap_region;
295 bool _heap_region_special;
296 size_t _num_regions;
297 ShenandoahHeapRegion** _regions;
298 uint8_t* _affiliations; // Holds array of enum ShenandoahAffiliation, including FREE status in non-generational mode
299
300 public:
301
302 inline HeapWord* base() const { return _heap_region.start(); }
303
304 inline size_t num_regions() const { return _num_regions; }
305 inline bool is_heap_region_special() { return _heap_region_special; }
306
307 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const;
308 inline size_t heap_region_index_containing(const void* addr) const;
309
310 inline ShenandoahHeapRegion* get_region(size_t region_idx) const;
311
312 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
313 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const;
314
315 inline ShenandoahMmuTracker* mmu_tracker() { return &_mmu_tracker; };
316
317 // ---------- GC state machinery
318 //
319 // GC state describes the important parts of collector state, that may be
320 // used to make barrier selection decisions in the native and generated code.
321 // Multiple bits can be set at once.
322 //
323 // Important invariant: when GC state is zero, the heap is stable, and no barriers
324 // are required.
325 //
326 public:
327 enum GCStateBitPos {
328 // Heap has forwarded objects: needs LRB barriers.
329 HAS_FORWARDED_BITPOS = 0,
330
331 // Heap is under marking: needs SATB barriers.
332 // For generational mode, it means either young or old marking, or both.
333 MARKING_BITPOS = 1,
334
335 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED)
336 EVACUATION_BITPOS = 2,
337
338 // Heap is under updating: needs no additional barriers.
339 UPDATEREFS_BITPOS = 3,
340
341 // Heap is under weak-reference/roots processing: needs weak-LRB barriers.
342 WEAK_ROOTS_BITPOS = 4,
343
344 // Young regions are under marking, need SATB barriers.
345 YOUNG_MARKING_BITPOS = 5,
346
347 // Old regions are under marking, need SATB barriers.
348 OLD_MARKING_BITPOS = 6
349 };
350
351 enum GCState {
352 STABLE = 0,
353 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS,
354 MARKING = 1 << MARKING_BITPOS,
355 EVACUATION = 1 << EVACUATION_BITPOS,
356 UPDATEREFS = 1 << UPDATEREFS_BITPOS,
357 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS,
358 YOUNG_MARKING = 1 << YOUNG_MARKING_BITPOS,
359 OLD_MARKING = 1 << OLD_MARKING_BITPOS
360 };
361
362 private:
363 bool _gc_state_changed;
364 ShenandoahSharedBitmap _gc_state;
365 ShenandoahSharedFlag _heap_changed;
366 ShenandoahSharedFlag _degenerated_gc_in_progress;
367 ShenandoahSharedFlag _full_gc_in_progress;
368 ShenandoahSharedFlag _full_gc_move_in_progress;
369 ShenandoahSharedFlag _concurrent_strong_root_in_progress;
370
371 size_t _gc_no_progress_count;
372
373 // This updates the singlular, global gc state. This must happen on a safepoint.
374 void set_gc_state(uint mask, bool value);
375
376 public:
377 char gc_state() const;
378
379 // This copies the global gc state into a thread local variable for java threads.
380 // It is primarily intended to support quick access at barriers.
381 void propagate_gc_state_to_java_threads();
382
383 // This is public to support assertions that the state hasn't been changed off of
384 // a safepoint and that any changes were propagated to java threads after the safepoint.
385 bool has_gc_state_changed() const { return _gc_state_changed; }
386
387 // Returns true if allocations have occurred in new regions or if regions have been
388 // uncommitted since the previous calls. This call will reset the flag to false.
389 bool has_changed() {
390 return _heap_changed.try_unset();
391 }
392
393 void set_concurrent_young_mark_in_progress(bool in_progress);
394 void set_concurrent_old_mark_in_progress(bool in_progress);
395 void set_evacuation_in_progress(bool in_progress);
396 void set_update_refs_in_progress(bool in_progress);
397 void set_degenerated_gc_in_progress(bool in_progress);
398 void set_full_gc_in_progress(bool in_progress);
399 void set_full_gc_move_in_progress(bool in_progress);
400 void set_has_forwarded_objects(bool cond);
401 void set_concurrent_strong_root_in_progress(bool cond);
402 void set_concurrent_weak_root_in_progress(bool cond);
403
404 inline bool is_stable() const;
405 inline bool is_idle() const;
406
407 inline bool is_concurrent_mark_in_progress() const;
408 inline bool is_concurrent_young_mark_in_progress() const;
409 inline bool is_concurrent_old_mark_in_progress() const;
410 inline bool is_update_refs_in_progress() const;
411 inline bool is_evacuation_in_progress() const;
412 inline bool is_degenerated_gc_in_progress() const;
413 inline bool is_full_gc_in_progress() const;
414 inline bool is_full_gc_move_in_progress() const;
415 inline bool has_forwarded_objects() const;
416
417 inline bool is_stw_gc_in_progress() const;
418 inline bool is_concurrent_strong_root_in_progress() const;
419 inline bool is_concurrent_weak_root_in_progress() const;
420 bool is_prepare_for_old_mark_in_progress() 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 protected:
463 // This is shared between shConcurrentGC and shDegenerateGC so that degenerated
464 // GC can resume update refs from where the concurrent GC was cancelled. It is
465 // also used in shGenerationalHeap, which uses a different closure for update refs.
466 ShenandoahRegionIterator _update_refs_iterator;
467
468 private:
469 // GC support
470 // Evacuation
471 virtual void evacuate_collection_set(bool concurrent);
472 // Concurrent root processing
473 void prepare_concurrent_roots();
474 void finish_concurrent_roots();
475 // Concurrent class unloading support
476 void do_class_unloading();
477 // Reference updating
478 void prepare_update_heap_references(bool concurrent);
479 virtual void update_heap_references(bool concurrent);
480 // Final update region states
481 void update_heap_region_states(bool concurrent);
482 virtual void final_update_refs_update_region_states();
483
484 void rendezvous_threads(const char* name);
485 void recycle_trash();
486 public:
487 void rebuild_free_set(bool concurrent);
488 void notify_gc_progress();
489 void notify_gc_no_progress();
490 size_t get_gc_no_progress_count() const;
491
492 //
493 // Mark support
494 private:
495 ShenandoahGeneration* _global_generation;
496
497 protected:
498 ShenandoahController* _control_thread;
499
500 ShenandoahYoungGeneration* _young_generation;
501 ShenandoahOldGeneration* _old_generation;
502
503 private:
504 ShenandoahCollectorPolicy* _shenandoah_policy;
505 ShenandoahMode* _gc_mode;
506 ShenandoahFreeSet* _free_set;
507 ShenandoahPacer* _pacer;
508 ShenandoahVerifier* _verifier;
509
510 ShenandoahPhaseTimings* _phase_timings;
511 ShenandoahMmuTracker _mmu_tracker;
512
513 public:
514 ShenandoahController* control_thread() { return _control_thread; }
515
516 ShenandoahGeneration* global_generation() const { return _global_generation; }
517 ShenandoahYoungGeneration* young_generation() const {
518 assert(mode()->is_generational(), "Young generation requires generational mode");
519 return _young_generation;
520 }
521
522 ShenandoahOldGeneration* old_generation() const {
523 assert(mode()->is_generational(), "Old generation requires generational mode");
524 return _old_generation;
525 }
526
527 ShenandoahGeneration* generation_for(ShenandoahAffiliation affiliation) const;
528
529 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; }
530 ShenandoahMode* mode() const { return _gc_mode; }
531 ShenandoahFreeSet* free_set() const { return _free_set; }
532 ShenandoahPacer* pacer() const { return _pacer; }
533
534 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; }
535
536 ShenandoahEvacOOMHandler* oom_evac_handler() { return &_oom_evac_handler; }
537
538 void on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation);
539 void on_cycle_end(ShenandoahGeneration* generation);
540
541 ShenandoahVerifier* verifier();
542
543 // ---------- VM subsystem bindings
544 //
545 private:
546 ShenandoahMonitoringSupport* _monitoring_support;
547 MemoryPool* _memory_pool;
548 GCMemoryManager _stw_memory_manager;
549 GCMemoryManager _cycle_memory_manager;
550 ConcurrentGCTimer* _gc_timer;
551 // For exporting to SA
552 int _log_min_obj_alignment_in_bytes;
553 public:
554 ShenandoahMonitoringSupport* monitoring_support() const { return _monitoring_support; }
555 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; }
556 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; }
557
558 GrowableArray<GCMemoryManager*> memory_managers() override;
559 GrowableArray<MemoryPool*> memory_pools() override;
560 MemoryUsage memory_usage() override;
561 GCTracer* tracer();
562 ConcurrentGCTimer* gc_timer() const;
563
564 // ---------- Class Unloading
565 //
566 private:
567 ShenandoahSharedFlag _unload_classes;
568 ShenandoahUnload _unloader;
569
570 public:
571 void set_unload_classes(bool uc);
572 bool unload_classes() const;
573
574 // Perform STW class unloading and weak root cleaning
575 void parallel_cleaning(bool full_gc);
576
577 private:
578 void stw_unload_classes(bool full_gc);
579 void stw_process_weak_roots(bool full_gc);
580 void stw_weak_refs(bool full_gc);
581
582 inline void assert_lock_for_affiliation(ShenandoahAffiliation orig_affiliation,
583 ShenandoahAffiliation new_affiliation);
584
585 // Heap iteration support
586 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops);
587 bool prepare_aux_bitmap_for_iteration();
588 void reclaim_aux_bitmap_for_iteration();
589
590 // ---------- Generic interface hooks
591 // Minor things that super-interface expects us to implement to play nice with
592 // the rest of runtime. Some of the things here are not required to be implemented,
593 // and can be stubbed out.
594 //
595 public:
596 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false);
597
598 // Check the pointer is in active part of Java heap.
599 // Use is_in_reserved to check if object is within heap bounds.
600 bool is_in(const void* p) const override;
601
602 // Returns true if the given oop belongs to a generation that is actively being collected.
603 inline bool is_in_active_generation(oop obj) const;
604 inline bool is_in_young(const void* p) const;
605 inline bool is_in_old(const void* p) const;
606
607 // Returns true iff the young generation is being collected and the given pointer
608 // is in the old generation. This is used to prevent the young collection from treating
609 // such an object as unreachable.
610 inline bool is_in_old_during_young_collection(oop obj) const;
611
612 inline ShenandoahAffiliation region_affiliation(const ShenandoahHeapRegion* r);
613 inline void set_affiliation(ShenandoahHeapRegion* r, ShenandoahAffiliation new_affiliation);
614
615 inline ShenandoahAffiliation region_affiliation(size_t index);
616
617 bool requires_barriers(stackChunkOop obj) const override;
618
619 MemRegion reserved_region() const { return _reserved; }
620 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); }
621
622 void collect(GCCause::Cause cause) override;
623 void do_full_collection(bool clear_all_soft_refs) override;
624
625 // Used for parsing heap during error printing
626 HeapWord* block_start(const void* addr) const;
627 bool block_is_obj(const HeapWord* addr) const;
628 bool print_location(outputStream* st, void* addr) const override;
629
630 // Used for native heap walkers: heap dumpers, mostly
631 void object_iterate(ObjectClosure* cl) override;
632 // Parallel heap iteration support
633 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override;
634
635 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
636 void keep_alive(oop obj) override;
637
638 // ---------- Safepoint interface hooks
639 //
640 public:
641 void safepoint_synchronize_begin() override;
642 void safepoint_synchronize_end() override;
643
644 // ---------- Code roots handling hooks
645 //
646 public:
647 void register_nmethod(nmethod* nm) override;
648 void unregister_nmethod(nmethod* nm) override;
649 void verify_nmethod(nmethod* nm) override {}
650
651 // ---------- Pinning hooks
652 //
653 public:
654 // Shenandoah supports per-object (per-region) pinning
655 void pin_object(JavaThread* thread, oop obj) override;
656 void unpin_object(JavaThread* thread, oop obj) override;
657
658 void sync_pinned_region_status();
659 void assert_pinned_region_status() NOT_DEBUG_RETURN;
660
661 // ---------- CDS archive support
662
663 bool can_load_archived_objects() const override { return !ShenandoahCardBarrier; }
664 HeapWord* allocate_loaded_archive_space(size_t size) override;
665 void complete_loaded_archive_space(MemRegion archive_space) override;
666
667 // ---------- Allocation support
668 //
669 protected:
670 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size);
671
672 private:
673 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region);
674 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size);
675 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size);
676
677 public:
678 HeapWord* allocate_memory(ShenandoahAllocRequest& request);
679 HeapWord* mem_allocate(size_t size, bool* what) override;
680 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
681 size_t size,
682 Metaspace::MetadataType mdtype) override;
683
684 void notify_mutator_alloc_words(size_t words, size_t waste);
685
686 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override;
687 size_t tlab_capacity(Thread *thr) const override;
688 size_t unsafe_max_tlab_alloc(Thread *thread) const override;
689 size_t max_tlab_size() const override;
690 size_t tlab_used(Thread* ignored) const override;
691
692 void ensure_parsability(bool retire_labs) override;
693
694 void labs_make_parsable();
695 void tlabs_retire(bool resize);
696 void gclabs_retire(bool resize);
697
698 // ---------- Marking support
699 //
700 private:
701 ShenandoahMarkingContext* _marking_context;
702 MemRegion _bitmap_region;
703 MemRegion _aux_bitmap_region;
704 MarkBitMap _verification_bit_map;
705 MarkBitMap _aux_bit_map;
706
707 size_t _bitmap_size;
708 size_t _bitmap_regions_per_slice;
709 size_t _bitmap_bytes_per_slice;
710
711 size_t _pretouch_heap_page_size;
712 size_t _pretouch_bitmap_page_size;
713
714 bool _bitmap_region_special;
715 bool _aux_bitmap_region_special;
716
717 ShenandoahLiveData** _liveness_cache;
718
719 public:
720 inline ShenandoahMarkingContext* complete_marking_context() const;
721 inline ShenandoahMarkingContext* marking_context() const;
722
723 template<class T>
724 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl);
725
726 template<class T>
727 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
728
729 template<class T>
730 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit);
731
732 // SATB barriers hooks
733 inline bool requires_marking(const void* entry) const;
734
735 // Support for bitmap uncommits
736 bool commit_bitmap_slice(ShenandoahHeapRegion *r);
737 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r);
738 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false);
739
740 // Liveness caching support
741 ShenandoahLiveData* get_liveness_cache(uint worker_id);
742 void flush_liveness_cache(uint worker_id);
743
744 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; }
745
746 // ---------- Evacuation support
747 //
748 private:
749 ShenandoahCollectionSet* _collection_set;
750 ShenandoahEvacOOMHandler _oom_evac_handler;
751
752 oop try_evacuate_object(oop src, Thread* thread, ShenandoahHeapRegion* from_region, ShenandoahAffiliation target_gen);
753 public:
754
755 static address in_cset_fast_test_addr();
756
757 ShenandoahCollectionSet* collection_set() const { return _collection_set; }
758
759 // Checks if object is in the collection set.
760 inline bool in_collection_set(oop obj) const;
761
762 // Checks if location is in the collection set. Can be interior pointer, not the oop itself.
763 inline bool in_collection_set_loc(void* loc) const;
764
765 // Evacuates or promotes object src. Returns the evacuated object, either evacuated
766 // by this thread, or by some other thread.
767 virtual oop evacuate_object(oop src, Thread* thread);
768
769 // Call before/after evacuation.
770 inline void enter_evacuation(Thread* t);
771 inline void leave_evacuation(Thread* t);
772
773 // ---------- Helper functions
774 //
775 public:
776 template <class T>
777 inline void conc_update_with_forwarded(T* p);
778
779 template <class T>
780 inline void non_conc_update_with_forwarded(T* p);
781
782 static inline void atomic_update_oop(oop update, oop* addr, oop compare);
783 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare);
784 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare);
785
786 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare);
787 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare);
788 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare);
789
790 static inline void atomic_clear_oop( oop* addr, oop compare);
791 static inline void atomic_clear_oop(narrowOop* addr, oop compare);
792 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare);
793
794 size_t trash_humongous_region_at(ShenandoahHeapRegion *r);
795
796 static inline void increase_object_age(oop obj, uint additional_age);
797
798 // Return the object's age, or a sentinel value when the age can't
799 // necessarily be determined because of concurrent locking by the
800 // mutator
801 static inline uint get_object_age(oop obj);
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