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