1 /*
2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/memAllocator.hpp"
30 #include "gc/shared/parallelCleaning.hpp"
31 #include "gc/shared/plab.hpp"
32
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahBrooksPointer.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
37 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
47 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
48 #include "gc/shenandoah/shenandoahMetrics.hpp"
49 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
50 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
51 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
52 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
53 #include "gc/shenandoah/shenandoahStringDedup.hpp"
54 #include "gc/shenandoah/shenandoahUtils.hpp"
55 #include "gc/shenandoah/shenandoahVerifier.hpp"
56 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
57 #include "gc/shenandoah/shenandoahVMOperations.hpp"
58 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
59 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
66
67 #include "memory/metaspace.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/safepointMechanism.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/mallocTracker.hpp"
72
73 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
74
75 #ifdef ASSERT
76 template <class T>
77 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
78 T o = RawAccess<>::oop_load(p);
79 if (! CompressedOops::is_null(o)) {
80 oop obj = CompressedOops::decode_not_null(o);
81 shenandoah_assert_not_forwarded(p, obj);
82 }
83 }
84
85 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
86 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
87 #endif
88
89 class ShenandoahPretouchTask : public AbstractGangTask {
90 private:
91 ShenandoahRegionIterator _regions;
92 char* _bitmap_base;
93 const size_t _bitmap_size;
94 const size_t _heap_page_size;
95 const size_t _bitmap_page_size;
96 public:
97 ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t heap_page_size, size_t bitmap_page_size) :
98 AbstractGangTask("Shenandoah PreTouch"),
99 _bitmap_base(bitmap_base),
100 _bitmap_size(bitmap_size),
101 _heap_page_size(heap_page_size),
102 _bitmap_page_size(bitmap_page_size) {}
103
104 virtual void work(uint worker_id) {
105 ShenandoahHeapRegion* r = _regions.next();
106 while (r != NULL) {
107 os::pretouch_memory(r->bottom(), r->end(), _heap_page_size);
108
109 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
110 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
111 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
112
113 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _bitmap_page_size);
114
115 r = _regions.next();
116 }
117 }
118 };
119
120 jint ShenandoahHeap::initialize() {
121 ShenandoahBrooksPointer::initial_checks();
122
123 initialize_heuristics();
124
125 //
126 // Figure out heap sizing
127 //
128
129 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
130 size_t max_byte_size = collector_policy()->max_heap_byte_size();
131 size_t heap_alignment = collector_policy()->heap_alignment();
132
133 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
134
135 if (ShenandoahAlwaysPreTouch) {
136 // Enabled pre-touch means the entire heap is committed right away.
137 init_byte_size = max_byte_size;
138 }
139
140 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
141 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
142
143 _num_regions = ShenandoahHeapRegion::region_count();
144
145 size_t num_committed_regions = init_byte_size / reg_size_bytes;
146 num_committed_regions = MIN2(num_committed_regions, _num_regions);
147 assert(num_committed_regions <= _num_regions, "sanity");
148
149 _initial_size = num_committed_regions * reg_size_bytes;
150 _committed = _initial_size;
151
152 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
153 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
154
155 //
156 // Reserve and commit memory for heap
157 //
158
159 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
160 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
161 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
162
163 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
164 "Misaligned heap: " PTR_FORMAT, p2i(base()));
165
166 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
167 os::commit_memory_or_exit(sh_rs.base(), _initial_size, false,
168 "Cannot commit heap memory");
169
170 //
171 // Reserve and commit memory for bitmap(s)
172 //
173
174 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
175 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
176
177 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
178
179 guarantee(bitmap_bytes_per_region != 0,
180 "Bitmap bytes per region should not be zero");
181 guarantee(is_power_of_2(bitmap_bytes_per_region),
182 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
183
184 if (bitmap_page_size > bitmap_bytes_per_region) {
185 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
186 _bitmap_bytes_per_slice = bitmap_page_size;
187 } else {
188 _bitmap_regions_per_slice = 1;
189 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
190 }
191
192 guarantee(_bitmap_regions_per_slice >= 1,
193 "Should have at least one region per slice: " SIZE_FORMAT,
194 _bitmap_regions_per_slice);
195
196 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
197 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
198 _bitmap_bytes_per_slice, bitmap_page_size);
199
200 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
201 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
202 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
203
204 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
205 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
206 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
207 os::commit_memory_or_exit((char *)_bitmap_region.start(), bitmap_init_commit, false,
208 "Cannot commit bitmap memory");
209
210 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
211
212 if (ShenandoahVerify) {
213 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
214 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
215 "Cannot commit verification bitmap memory");
216 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
217 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
218 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
219 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
220 }
221
222 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
223 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
224 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
225 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
226 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
227
228 //
229 // Create regions and region sets
230 //
231
232 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
233 _free_set = new ShenandoahFreeSet(this, _num_regions);
234 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)sh_rs.base());
235
236 {
237 ShenandoahHeapLocker locker(lock());
238
239 size_t size_words = ShenandoahHeapRegion::region_size_words();
240
241 for (size_t i = 0; i < _num_regions; i++) {
242 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
243 bool is_committed = i < num_committed_regions;
244 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
245
246 _marking_context->initialize_top_at_mark_start(r);
247 _regions[i] = r;
248 assert(!collection_set()->is_in(i), "New region should not be in collection set");
249 }
250
251 // Initialize to complete
252 _marking_context->mark_complete();
253
254 _free_set->rebuild();
255 }
256
257 if (ShenandoahAlwaysPreTouch) {
258 assert(!AlwaysPreTouch, "Should have been overridden");
259
260 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
261 // before initialize() below zeroes it with initializing thread. For any given region,
262 // we touch the region and the corresponding bitmaps from the same thread.
263 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
264
265 log_info(gc, init)("Pretouch " SIZE_FORMAT " regions; page sizes: " SIZE_FORMAT " heap, " SIZE_FORMAT " bitmap",
266 _num_regions, heap_page_size, bitmap_page_size);
267 ShenandoahPretouchTask cl(bitmap.base(), _bitmap_size, heap_page_size, bitmap_page_size);
268 _workers->run_task(&cl);
269 }
270
271 //
272 // Initialize the rest of GC subsystems
273 //
274
275 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
276 for (uint worker = 0; worker < _max_workers; worker++) {
277 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
278 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
279 }
280
281 // The call below uses stuff (the SATB* things) that are in G1, but probably
282 // belong into a shared location.
283 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
284 SATB_Q_CBL_mon,
285 20 /* G1SATBProcessCompletedThreshold */,
286 60 /* G1SATBBufferEnqueueingThresholdPercent */);
287
288 _monitoring_support = new ShenandoahMonitoringSupport(this);
289 _phase_timings = new ShenandoahPhaseTimings();
290 ShenandoahStringDedup::initialize();
291 ShenandoahCodeRoots::initialize();
292
293 if (ShenandoahAllocationTrace) {
294 _alloc_tracker = new ShenandoahAllocTracker();
295 }
296
297 if (ShenandoahPacing) {
298 _pacer = new ShenandoahPacer(this);
299 _pacer->setup_for_idle();
300 } else {
301 _pacer = NULL;
302 }
303
304 _traversal_gc = heuristics()->can_do_traversal_gc() ?
305 new ShenandoahTraversalGC(this, _num_regions) :
306 NULL;
307
308 _control_thread = new ShenandoahControlThread();
309
310 log_info(gc, init)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
311 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
312
313 log_info(gc, init)("Safepointing mechanism: %s",
314 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
315 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
316
317 return JNI_OK;
318 }
319
320 void ShenandoahHeap::initialize_heuristics() {
321 if (ShenandoahGCHeuristics != NULL) {
322 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
323 _heuristics = new ShenandoahAggressiveHeuristics();
324 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
325 _heuristics = new ShenandoahStaticHeuristics();
326 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
327 _heuristics = new ShenandoahAdaptiveHeuristics();
328 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
329 _heuristics = new ShenandoahPassiveHeuristics();
330 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
331 _heuristics = new ShenandoahCompactHeuristics();
332 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
333 _heuristics = new ShenandoahTraversalHeuristics();
334 } else {
335 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
336 }
337
338 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
339 vm_exit_during_initialization(
340 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
341 _heuristics->name()));
342 }
343 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
344 vm_exit_during_initialization(
345 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
346 _heuristics->name()));
347 }
348
349 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
350 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
351 }
352 log_info(gc, init)("Shenandoah heuristics: %s",
353 _heuristics->name());
354 } else {
355 ShouldNotReachHere();
356 }
357
358 }
359
360 #ifdef _MSC_VER
361 #pragma warning( push )
362 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
363 #endif
364
365 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
366 CollectedHeap(),
367 _initial_size(0),
368 _used(0),
369 _committed(0),
370 _bytes_allocated_since_gc_start(0),
371 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
372 _workers(NULL),
373 _safepoint_workers(NULL),
374 _num_regions(0),
375 _regions(NULL),
376 _update_refs_iterator(this),
377 _control_thread(NULL),
378 _shenandoah_policy(policy),
379 _heuristics(NULL),
380 _free_set(NULL),
381 _scm(new ShenandoahConcurrentMark()),
382 _traversal_gc(NULL),
383 _full_gc(new ShenandoahMarkCompact()),
384 _pacer(NULL),
385 _verifier(NULL),
386 _alloc_tracker(NULL),
387 _phase_timings(NULL),
388 _monitoring_support(NULL),
389 _memory_pool(NULL),
390 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
391 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
392 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
393 _soft_ref_policy(),
394 _ref_processor(NULL),
395 _marking_context(NULL),
396 _bitmap_size(0),
397 _bitmap_regions_per_slice(0),
398 _bitmap_bytes_per_slice(0),
399 _liveness_cache(NULL),
400 _collection_set(NULL)
401 {
402 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
403 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
404
405 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
406
407 _max_workers = MAX2(_max_workers, 1U);
408 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
409 /* are_GC_task_threads */true,
410 /* are_ConcurrentGC_threads */false);
411 if (_workers == NULL) {
412 vm_exit_during_initialization("Failed necessary allocation.");
413 } else {
414 _workers->initialize_workers();
415 }
416
417 if (ShenandoahParallelSafepointThreads > 1) {
418 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
419 ShenandoahParallelSafepointThreads,
420 false, false);
421 _safepoint_workers->initialize_workers();
422 }
423 }
424
425 #ifdef _MSC_VER
426 #pragma warning( pop )
427 #endif
428
429 class ShenandoahResetBitmapTask : public AbstractGangTask {
430 private:
431 ShenandoahRegionIterator _regions;
432
433 public:
434 ShenandoahResetBitmapTask() :
435 AbstractGangTask("Parallel Reset Bitmap Task") {}
436
437 void work(uint worker_id) {
438 ShenandoahHeapRegion* region = _regions.next();
439 ShenandoahHeap* heap = ShenandoahHeap::heap();
440 ShenandoahMarkingContext* const ctx = heap->marking_context();
441 while (region != NULL) {
442 if (heap->is_bitmap_slice_committed(region)) {
443 ctx->clear_bitmap(region);
444 }
445 region = _regions.next();
446 }
447 }
448 };
449
450 void ShenandoahHeap::reset_mark_bitmap() {
451 assert_gc_workers(_workers->active_workers());
452 mark_incomplete_marking_context();
453
454 ShenandoahResetBitmapTask task;
455 _workers->run_task(&task);
456 }
457
458 void ShenandoahHeap::print_on(outputStream* st) const {
459 st->print_cr("Shenandoah Heap");
460 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
461 capacity() / K, committed() / K, used() / K);
462 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
463 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
464
465 st->print("Status: ");
466 if (has_forwarded_objects()) st->print("has forwarded objects, ");
467 if (is_concurrent_mark_in_progress()) st->print("marking, ");
468 if (is_evacuation_in_progress()) st->print("evacuating, ");
469 if (is_update_refs_in_progress()) st->print("updating refs, ");
470 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
471 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
472 if (is_full_gc_in_progress()) st->print("full gc, ");
473 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
474
475 if (cancelled_gc()) {
476 st->print("cancelled");
477 } else {
478 st->print("not cancelled");
479 }
480 st->cr();
481
482 st->print_cr("Reserved region:");
483 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
484 p2i(reserved_region().start()),
485 p2i(reserved_region().end()));
486
487 st->cr();
488 MetaspaceUtils::print_on(st);
489
490 if (Verbose) {
491 print_heap_regions_on(st);
492 }
493 }
494
495 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
496 public:
497 void do_thread(Thread* thread) {
498 assert(thread != NULL, "Sanity");
499 assert(thread->is_Worker_thread(), "Only worker thread expected");
500 ShenandoahThreadLocalData::initialize_gclab(thread);
501 }
502 };
503
504 void ShenandoahHeap::post_initialize() {
505 CollectedHeap::post_initialize();
506 MutexLocker ml(Threads_lock);
507
508 ShenandoahInitWorkerGCLABClosure init_gclabs;
509 _workers->threads_do(&init_gclabs);
510
511 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
512 // Now, we will let WorkGang to initialize gclab when new worker is created.
513 _workers->set_initialize_gclab();
514
515 _scm->initialize(_max_workers);
516 _full_gc->initialize(_gc_timer);
517
518 ref_processing_init();
519
520 _heuristics->initialize();
521 }
522
523 size_t ShenandoahHeap::used() const {
524 return OrderAccess::load_acquire(&_used);
525 }
526
527 size_t ShenandoahHeap::committed() const {
528 OrderAccess::acquire();
529 return _committed;
530 }
531
532 void ShenandoahHeap::increase_committed(size_t bytes) {
533 assert_heaplock_or_safepoint();
534 _committed += bytes;
535 }
536
537 void ShenandoahHeap::decrease_committed(size_t bytes) {
538 assert_heaplock_or_safepoint();
539 _committed -= bytes;
540 }
541
542 void ShenandoahHeap::increase_used(size_t bytes) {
543 Atomic::add(bytes, &_used);
544 }
545
546 void ShenandoahHeap::set_used(size_t bytes) {
547 OrderAccess::release_store_fence(&_used, bytes);
548 }
549
550 void ShenandoahHeap::decrease_used(size_t bytes) {
551 assert(used() >= bytes, "never decrease heap size by more than we've left");
552 Atomic::sub(bytes, &_used);
553 }
554
555 void ShenandoahHeap::increase_allocated(size_t bytes) {
556 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
557 }
558
559 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
560 size_t bytes = words * HeapWordSize;
561 if (!waste) {
562 increase_used(bytes);
563 }
564 increase_allocated(bytes);
565 if (ShenandoahPacing) {
566 control_thread()->pacing_notify_alloc(words);
567 if (waste) {
568 pacer()->claim_for_alloc(words, true);
569 }
570 }
571 }
572
573 size_t ShenandoahHeap::capacity() const {
574 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
575 }
576
577 size_t ShenandoahHeap::max_capacity() const {
578 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
579 }
580
581 size_t ShenandoahHeap::initial_capacity() const {
582 return _initial_size;
583 }
584
585 bool ShenandoahHeap::is_in(const void* p) const {
586 HeapWord* heap_base = (HeapWord*) base();
587 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
588 return p >= heap_base && p < last_region_end;
589 }
590
591 void ShenandoahHeap::op_uncommit(double shrink_before) {
592 assert (ShenandoahUncommit, "should be enabled");
593
594 size_t count = 0;
595 for (size_t i = 0; i < num_regions(); i++) {
596 ShenandoahHeapRegion* r = get_region(i);
597 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
598 ShenandoahHeapLocker locker(lock());
599 if (r->is_empty_committed()) {
600 r->make_uncommitted();
601 count++;
602 }
603 }
604 SpinPause(); // allow allocators to take the lock
605 }
606
607 if (count > 0) {
608 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
609 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
610 control_thread()->notify_heap_changed();
611 }
612 }
613
614 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
615 // New object should fit the GCLAB size
616 size_t min_size = MAX2(size, PLAB::min_size());
617
618 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
619 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
620 new_size = MIN2(new_size, PLAB::max_size());
621 new_size = MAX2(new_size, PLAB::min_size());
622
623 // Record new heuristic value even if we take any shortcut. This captures
624 // the case when moderately-sized objects always take a shortcut. At some point,
625 // heuristics should catch up with them.
626 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
627
628 if (new_size < size) {
629 // New size still does not fit the object. Fall back to shared allocation.
630 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
631 return NULL;
632 }
633
634 // Retire current GCLAB, and allocate a new one.
635 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
636 gclab->retire();
637
638 size_t actual_size = 0;
639 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
640 if (gclab_buf == NULL) {
641 return NULL;
642 }
643
644 assert (size <= actual_size, "allocation should fit");
645
646 if (ZeroTLAB) {
647 // ..and clear it.
648 Copy::zero_to_words(gclab_buf, actual_size);
649 } else {
650 // ...and zap just allocated object.
651 #ifdef ASSERT
652 // Skip mangling the space corresponding to the object header to
653 // ensure that the returned space is not considered parsable by
654 // any concurrent GC thread.
655 size_t hdr_size = oopDesc::header_size();
656 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
657 #endif // ASSERT
658 }
659 gclab->set_buf(gclab_buf, actual_size);
660 return gclab->allocate(size);
661 }
662
663 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
664 size_t requested_size,
665 size_t* actual_size) {
666 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
667 HeapWord* res = allocate_memory(req);
668 if (res != NULL) {
669 *actual_size = req.actual_size();
670 } else {
671 *actual_size = 0;
672 }
673 return res;
674 }
675
676 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
677 size_t word_size,
678 size_t* actual_size) {
679 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
680 HeapWord* res = allocate_memory(req);
681 if (res != NULL) {
682 *actual_size = req.actual_size();
683 } else {
684 *actual_size = 0;
685 }
686 return res;
687 }
688
689 ShenandoahHeap* ShenandoahHeap::heap() {
690 CollectedHeap* heap = Universe::heap();
691 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
692 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
693 return (ShenandoahHeap*) heap;
694 }
695
696 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
697 CollectedHeap* heap = Universe::heap();
698 return (ShenandoahHeap*) heap;
699 }
700
701 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
702 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
703
704 intptr_t pacer_epoch = 0;
705 bool in_new_region = false;
706 HeapWord* result = NULL;
707
708 if (req.is_mutator_alloc()) {
709 if (ShenandoahPacing) {
710 pacer()->pace_for_alloc(req.size());
711 pacer_epoch = pacer()->epoch();
712 }
713
714 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
715 result = allocate_memory_under_lock(req, in_new_region);
716 }
717
718 // Allocation failed, block until control thread reacted, then retry allocation.
719 //
720 // It might happen that one of the threads requesting allocation would unblock
721 // way later after GC happened, only to fail the second allocation, because
722 // other threads have already depleted the free storage. In this case, a better
723 // strategy is to try again, as long as GC makes progress.
724 //
725 // Then, we need to make sure the allocation was retried after at least one
726 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
727
728 size_t tries = 0;
729
730 while (result == NULL && _progress_last_gc.is_set()) {
731 tries++;
732 control_thread()->handle_alloc_failure(req.size());
733 result = allocate_memory_under_lock(req, in_new_region);
734 }
735
736 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
737 tries++;
738 control_thread()->handle_alloc_failure(req.size());
739 result = allocate_memory_under_lock(req, in_new_region);
740 }
741
742 } else {
743 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
744 result = allocate_memory_under_lock(req, in_new_region);
745 // Do not call handle_alloc_failure() here, because we cannot block.
746 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
747 }
748
749 if (in_new_region) {
750 control_thread()->notify_heap_changed();
751 }
752
753 if (result != NULL) {
754 size_t requested = req.size();
755 size_t actual = req.actual_size();
756
757 assert (req.is_lab_alloc() || (requested == actual),
758 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
759 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
760
761 if (req.is_mutator_alloc()) {
762 notify_mutator_alloc_words(actual, false);
763
764 // If we requested more than we were granted, give the rest back to pacer.
765 // This only matters if we are in the same pacing epoch: do not try to unpace
766 // over the budget for the other phase.
767 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
768 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
769 }
770 } else {
771 increase_used(actual*HeapWordSize);
772 }
773 }
774
775 return result;
776 }
777
778 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
779 ShenandoahHeapLocker locker(lock());
780 return _free_set->allocate(req, in_new_region);
781 }
782
783 class ShenandoahMemAllocator : public MemAllocator {
784 private:
785 MemAllocator& _initializer;
786 public:
787 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
788 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
789 _initializer(initializer) {}
790
791 protected:
792 virtual HeapWord* mem_allocate(Allocation& allocation) const {
793 HeapWord* result = MemAllocator::mem_allocate(allocation);
794 // Initialize brooks-pointer
795 if (result != NULL) {
796 result += ShenandoahBrooksPointer::word_size();
797 ShenandoahBrooksPointer::initialize(oop(result));
798 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
799 }
800 return result;
801 }
802
803 virtual oop initialize(HeapWord* mem) const {
804 return _initializer.initialize(mem);
805 }
806 };
807
808 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
809 ObjAllocator initializer(klass, size, THREAD);
810 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
811 return allocator.allocate();
812 }
813
814 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
815 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
816 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
817 return allocator.allocate();
818 }
819
820 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
821 ClassAllocator initializer(klass, size, THREAD);
822 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
823 return allocator.allocate();
824 }
825
826 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
827 bool* gc_overhead_limit_was_exceeded) {
828 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
829 return allocate_memory(req);
830 }
831
832 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
833 size_t size,
834 Metaspace::MetadataType mdtype) {
835 MetaWord* result;
836
837 // Inform metaspace OOM to GC heuristics if class unloading is possible.
838 if (heuristics()->can_unload_classes()) {
839 ShenandoahHeuristics* h = heuristics();
840 h->record_metaspace_oom();
841 }
842
843 // Expand and retry allocation
844 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
845 if (result != NULL) {
846 return result;
847 }
848
849 // Start full GC
850 collect(GCCause::_metadata_GC_clear_soft_refs);
851
852 // Retry allocation
853 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
854 if (result != NULL) {
855 return result;
856 }
857
858 // Expand and retry allocation
859 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
860 if (result != NULL) {
861 return result;
862 }
863
864 // Out of memory
865 return NULL;
866 }
867
868 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
869 HeapWord* obj = tlab_post_allocation_setup(start);
870 CollectedHeap::fill_with_object(obj, end);
871 }
872
873 size_t ShenandoahHeap::min_dummy_object_size() const {
874 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
875 }
876
877 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
878 private:
879 ShenandoahHeap* _heap;
880 Thread* _thread;
881 public:
882 ShenandoahEvacuateUpdateRootsClosure() :
883 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
884 }
885
886 private:
887 template <class T>
888 void do_oop_work(T* p) {
889 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
890
891 T o = RawAccess<>::oop_load(p);
892 if (! CompressedOops::is_null(o)) {
893 oop obj = CompressedOops::decode_not_null(o);
894 if (_heap->in_collection_set(obj)) {
895 shenandoah_assert_marked(p, obj);
896 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
897 if (oopDesc::equals_raw(resolved, obj)) {
898 resolved = _heap->evacuate_object(obj, _thread);
899 }
900 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
901 }
902 }
903 }
904
905 public:
906 void do_oop(oop* p) {
907 do_oop_work(p);
908 }
909 void do_oop(narrowOop* p) {
910 do_oop_work(p);
911 }
912 };
913
914 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
915 private:
916 ShenandoahHeap* const _heap;
917 Thread* const _thread;
918 public:
919 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
920 _heap(heap), _thread(Thread::current()) {}
921
922 void do_object(oop p) {
923 shenandoah_assert_marked(NULL, p);
924 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
925 _heap->evacuate_object(p, _thread);
926 }
927 }
928 };
929
930 class ShenandoahEvacuationTask : public AbstractGangTask {
931 private:
932 ShenandoahHeap* const _sh;
933 ShenandoahCollectionSet* const _cs;
934 bool _concurrent;
935 public:
936 ShenandoahEvacuationTask(ShenandoahHeap* sh,
937 ShenandoahCollectionSet* cs,
938 bool concurrent) :
939 AbstractGangTask("Parallel Evacuation Task"),
940 _sh(sh),
941 _cs(cs),
942 _concurrent(concurrent)
943 {}
944
945 void work(uint worker_id) {
946 if (_concurrent) {
947 ShenandoahConcurrentWorkerSession worker_session(worker_id);
948 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
949 ShenandoahEvacOOMScope oom_evac_scope;
950 do_work();
951 } else {
952 ShenandoahParallelWorkerSession worker_session(worker_id);
953 ShenandoahEvacOOMScope oom_evac_scope;
954 do_work();
955 }
956 }
957
958 private:
959 void do_work() {
960 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
961 ShenandoahHeapRegion* r;
962 while ((r =_cs->claim_next()) != NULL) {
963 assert(r->has_live(), "all-garbage regions are reclaimed early");
964 _sh->marked_object_iterate(r, &cl);
965
966 if (ShenandoahPacing) {
967 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
968 }
969
970 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
971 break;
972 }
973 }
974 }
975 };
976
977 void ShenandoahHeap::trash_cset_regions() {
978 ShenandoahHeapLocker locker(lock());
979
980 ShenandoahCollectionSet* set = collection_set();
981 ShenandoahHeapRegion* r;
982 set->clear_current_index();
983 while ((r = set->next()) != NULL) {
984 r->make_trash();
985 }
986 collection_set()->clear();
987 }
988
989 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
990 st->print_cr("Heap Regions:");
991 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
992 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
993 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
994 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
995
996 for (size_t i = 0; i < num_regions(); i++) {
997 get_region(i)->print_on(st);
998 }
999 }
1000
1001 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1002 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1003
1004 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
1005 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
1006 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1007 size_t index = start->region_number() + required_regions - 1;
1008
1009 assert(!start->has_live(), "liveness must be zero");
1010
1011 for(size_t i = 0; i < required_regions; i++) {
1012 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1013 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1014 ShenandoahHeapRegion* region = get_region(index --);
1015
1016 assert(region->is_humongous(), "expect correct humongous start or continuation");
1017 assert(!region->is_cset(), "Humongous region should not be in collection set");
1018
1019 region->make_trash_immediate();
1020 }
1021 }
1022
1023 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1024 public:
1025 void do_thread(Thread* thread) {
1026 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1027 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1028 gclab->retire();
1029 }
1030 };
1031
1032 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1033 if (UseTLAB) {
1034 CollectedHeap::ensure_parsability(retire_tlabs);
1035 }
1036 ShenandoahRetireGCLABClosure cl;
1037 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1038 cl.do_thread(t);
1039 }
1040 workers()->threads_do(&cl);
1041 }
1042
1043 void ShenandoahHeap::resize_tlabs() {
1044 CollectedHeap::resize_all_tlabs();
1045 }
1046
1047 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1048 private:
1049 ShenandoahRootEvacuator* _rp;
1050
1051 public:
1052 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1053 AbstractGangTask("Shenandoah evacuate and update roots"),
1054 _rp(rp) {}
1055
1056 void work(uint worker_id) {
1057 ShenandoahParallelWorkerSession worker_session(worker_id);
1058 ShenandoahEvacOOMScope oom_evac_scope;
1059 ShenandoahEvacuateUpdateRootsClosure cl;
1060
1061 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1062 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1063 }
1064 };
1065
1066 void ShenandoahHeap::evacuate_and_update_roots() {
1067 #if defined(COMPILER2) || INCLUDE_JVMCI
1068 DerivedPointerTable::clear();
1069 #endif
1070 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1071
1072 {
1073 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1074 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1075 workers()->run_task(&roots_task);
1076 }
1077
1078 #if defined(COMPILER2) || INCLUDE_JVMCI
1079 DerivedPointerTable::update_pointers();
1080 #endif
1081 }
1082
1083 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1084 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1085
1086 CodeBlobToOopClosure blobsCl(cl, false);
1087 CLDToOopClosure cldCl(cl, ClassLoaderData::_claim_strong);
1088
1089 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1090 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1091 }
1092
1093 // Returns size in bytes
1094 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1095 if (ShenandoahElasticTLAB) {
1096 // With Elastic TLABs, return the max allowed size, and let the allocation path
1097 // figure out the safe size for current allocation.
1098 return ShenandoahHeapRegion::max_tlab_size_bytes();
1099 } else {
1100 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1101 }
1102 }
1103
1104 size_t ShenandoahHeap::max_tlab_size() const {
1105 // Returns size in words
1106 return ShenandoahHeapRegion::max_tlab_size_words();
1107 }
1108
1109 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1110 public:
1111 void do_thread(Thread* thread) {
1112 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1113 gclab->retire();
1114 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1115 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1116 }
1117 }
1118 };
1119
1120 void ShenandoahHeap::retire_and_reset_gclabs() {
1121 ShenandoahRetireAndResetGCLABClosure cl;
1122 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1123 cl.do_thread(t);
1124 }
1125 workers()->threads_do(&cl);
1126 }
1127
1128 void ShenandoahHeap::collect(GCCause::Cause cause) {
1129 control_thread()->request_gc(cause);
1130 }
1131
1132 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1133 //assert(false, "Shouldn't need to do full collections");
1134 }
1135
1136 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1137 return _shenandoah_policy;
1138 }
1139
1140 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1141 Space* sp = heap_region_containing(addr);
1142 if (sp != NULL) {
1143 return sp->block_start(addr);
1144 }
1145 return NULL;
1146 }
1147
1148 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1149 Space* sp = heap_region_containing(addr);
1150 assert(sp != NULL, "block_size of address outside of heap");
1151 return sp->block_size(addr);
1152 }
1153
1154 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1155 Space* sp = heap_region_containing(addr);
1156 return sp->block_is_obj(addr);
1157 }
1158
1159 jlong ShenandoahHeap::millis_since_last_gc() {
1160 double v = heuristics()->time_since_last_gc() * 1000;
1161 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1162 return (jlong)v;
1163 }
1164
1165 void ShenandoahHeap::prepare_for_verify() {
1166 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1167 make_parsable(false);
1168 }
1169 }
1170
1171 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1172 workers()->print_worker_threads_on(st);
1173 if (ShenandoahStringDedup::is_enabled()) {
1174 ShenandoahStringDedup::print_worker_threads_on(st);
1175 }
1176 }
1177
1178 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1179 workers()->threads_do(tcl);
1180 _safepoint_workers->threads_do(tcl);
1181 if (ShenandoahStringDedup::is_enabled()) {
1182 ShenandoahStringDedup::threads_do(tcl);
1183 }
1184 }
1185
1186 void ShenandoahHeap::print_tracing_info() const {
1187 LogTarget(Info, gc, stats) lt;
1188 if (lt.is_enabled()) {
1189 ResourceMark rm;
1190 LogStream ls(lt);
1191
1192 phase_timings()->print_on(&ls);
1193
1194 ls.cr();
1195 ls.cr();
1196
1197 shenandoah_policy()->print_gc_stats(&ls);
1198
1199 ls.cr();
1200 ls.cr();
1201
1202 if (ShenandoahPacing) {
1203 pacer()->print_on(&ls);
1204 }
1205
1206 ls.cr();
1207 ls.cr();
1208
1209 if (ShenandoahAllocationTrace) {
1210 assert(alloc_tracker() != NULL, "Must be");
1211 alloc_tracker()->print_on(&ls);
1212 } else {
1213 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1214 }
1215 }
1216 }
1217
1218 void ShenandoahHeap::verify(VerifyOption vo) {
1219 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1220 if (ShenandoahVerify) {
1221 verifier()->verify_generic(vo);
1222 } else {
1223 // TODO: Consider allocating verification bitmaps on demand,
1224 // and turn this on unconditionally.
1225 }
1226 }
1227 }
1228 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1229 return _free_set->capacity();
1230 }
1231
1232 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1233 private:
1234 MarkBitMap* _bitmap;
1235 Stack<oop,mtGC>* _oop_stack;
1236
1237 template <class T>
1238 void do_oop_work(T* p) {
1239 T o = RawAccess<>::oop_load(p);
1240 if (!CompressedOops::is_null(o)) {
1241 oop obj = CompressedOops::decode_not_null(o);
1242 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1243 assert(oopDesc::is_oop(obj), "must be a valid oop");
1244 if (!_bitmap->is_marked((HeapWord*) obj)) {
1245 _bitmap->mark((HeapWord*) obj);
1246 _oop_stack->push(obj);
1247 }
1248 }
1249 }
1250 public:
1251 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1252 _bitmap(bitmap), _oop_stack(oop_stack) {}
1253 void do_oop(oop* p) { do_oop_work(p); }
1254 void do_oop(narrowOop* p) { do_oop_work(p); }
1255 };
1256
1257 /*
1258 * This is public API, used in preparation of object_iterate().
1259 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1260 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1261 * control, we call SH::make_tlabs_parsable().
1262 */
1263 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1264 // No-op.
1265 }
1266
1267 /*
1268 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1269 *
1270 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1271 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1272 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1273 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1274 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1275 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1276 * wiped the bitmap in preparation for next marking).
1277 *
1278 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1279 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1280 * is allowed to report dead objects, but is not required to do so.
1281 */
1282 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1283 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1284 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1285 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1286 return;
1287 }
1288
1289 // Reset bitmap
1290 _aux_bit_map.clear();
1291
1292 Stack<oop,mtGC> oop_stack;
1293
1294 // First, we process all GC roots. This populates the work stack with initial objects.
1295 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1296 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1297 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1298 CodeBlobToOopClosure blobs(&oops, false);
1299 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1300
1301 // Work through the oop stack to traverse heap.
1302 while (! oop_stack.is_empty()) {
1303 oop obj = oop_stack.pop();
1304 assert(oopDesc::is_oop(obj), "must be a valid oop");
1305 cl->do_object(obj);
1306 obj->oop_iterate(&oops);
1307 }
1308
1309 assert(oop_stack.is_empty(), "should be empty");
1310
1311 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1312 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1313 }
1314 }
1315
1316 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1317 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1318 object_iterate(cl);
1319 }
1320
1321 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1322 for (size_t i = 0; i < num_regions(); i++) {
1323 ShenandoahHeapRegion* current = get_region(i);
1324 blk->heap_region_do(current);
1325 }
1326 }
1327
1328 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1329 private:
1330 ShenandoahHeap* const _heap;
1331 ShenandoahHeapRegionClosure* const _blk;
1332
1333 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1334 volatile size_t _index;
1335 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1336
1337 public:
1338 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1339 AbstractGangTask("Parallel Region Task"),
1340 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1341
1342 void work(uint worker_id) {
1343 size_t stride = ShenandoahParallelRegionStride;
1344
1345 size_t max = _heap->num_regions();
1346 while (_index < max) {
1347 size_t cur = Atomic::add(stride, &_index) - stride;
1348 size_t start = cur;
1349 size_t end = MIN2(cur + stride, max);
1350 if (start >= max) break;
1351
1352 for (size_t i = cur; i < end; i++) {
1353 ShenandoahHeapRegion* current = _heap->get_region(i);
1354 _blk->heap_region_do(current);
1355 }
1356 }
1357 }
1358 };
1359
1360 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1361 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1362 if (num_regions() > ShenandoahParallelRegionStride) {
1363 ShenandoahParallelHeapRegionTask task(blk);
1364 workers()->run_task(&task);
1365 } else {
1366 heap_region_iterate(blk);
1367 }
1368 }
1369
1370 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1371 private:
1372 ShenandoahMarkingContext* const _ctx;
1373 public:
1374 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1375
1376 void heap_region_do(ShenandoahHeapRegion* r) {
1377 if (r->is_active()) {
1378 r->clear_live_data();
1379 _ctx->capture_top_at_mark_start(r);
1380 } else {
1381 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1382 assert(_ctx->top_at_mark_start(r) == r->top(),
1383 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1384 }
1385 }
1386
1387 bool is_thread_safe() { return true; }
1388 };
1389
1390 void ShenandoahHeap::op_init_mark() {
1391 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1392 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1393
1394 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1395 assert(!marking_context()->is_complete(), "should not be complete");
1396
1397 if (ShenandoahVerify) {
1398 verifier()->verify_before_concmark();
1399 }
1400
1401 if (VerifyBeforeGC) {
1402 Universe::verify();
1403 }
1404
1405 set_concurrent_mark_in_progress(true);
1406 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1407 {
1408 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1409 make_parsable(true);
1410 }
1411
1412 {
1413 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1414 ShenandoahClearLivenessClosure clc;
1415 parallel_heap_region_iterate(&clc);
1416 }
1417
1418 // Make above changes visible to worker threads
1419 OrderAccess::fence();
1420
1421 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1422
1423 if (UseTLAB) {
1424 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1425 resize_tlabs();
1426 }
1427
1428 if (ShenandoahPacing) {
1429 pacer()->setup_for_mark();
1430 }
1431 }
1432
1433 void ShenandoahHeap::op_mark() {
1434 concurrent_mark()->mark_from_roots();
1435 }
1436
1437 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1438 private:
1439 ShenandoahMarkingContext* const _ctx;
1440 public:
1441 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1442
1443 void heap_region_do(ShenandoahHeapRegion* r) {
1444 if (r->is_active()) {
1445 HeapWord *tams = _ctx->top_at_mark_start(r);
1446 HeapWord *top = r->top();
1447 if (top > tams) {
1448 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1449 }
1450 } else {
1451 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1452 assert(_ctx->top_at_mark_start(r) == r->top(),
1453 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1454 }
1455 }
1456
1457 bool is_thread_safe() { return true; }
1458 };
1459
1460 void ShenandoahHeap::op_final_mark() {
1461 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1462
1463 // It is critical that we
1464 // evacuate roots right after finishing marking, so that we don't
1465 // get unmarked objects in the roots.
1466
1467 if (!cancelled_gc()) {
1468 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1469
1470 if (has_forwarded_objects()) {
1471 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1472 }
1473
1474 stop_concurrent_marking();
1475
1476 {
1477 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1478
1479 // All allocations past TAMS are implicitly live, adjust the region data.
1480 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1481 ShenandoahCompleteLivenessClosure cl;
1482 parallel_heap_region_iterate(&cl);
1483 }
1484
1485 {
1486 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1487
1488 make_parsable(true);
1489
1490 trash_cset_regions();
1491
1492 {
1493 ShenandoahHeapLocker locker(lock());
1494 _collection_set->clear();
1495 _free_set->clear();
1496
1497 heuristics()->choose_collection_set(_collection_set);
1498
1499 _free_set->rebuild();
1500 }
1501 }
1502
1503 // If collection set has candidates, start evacuation.
1504 // Otherwise, bypass the rest of the cycle.
1505 if (!collection_set()->is_empty()) {
1506 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1507
1508 if (ShenandoahVerify) {
1509 verifier()->verify_before_evacuation();
1510 }
1511
1512 set_evacuation_in_progress(true);
1513 // From here on, we need to update references.
1514 set_has_forwarded_objects(true);
1515
1516 evacuate_and_update_roots();
1517
1518 if (ShenandoahPacing) {
1519 pacer()->setup_for_evac();
1520 }
1521 } else {
1522 if (ShenandoahVerify) {
1523 verifier()->verify_after_concmark();
1524 }
1525
1526 if (VerifyAfterGC) {
1527 Universe::verify();
1528 }
1529 }
1530
1531 } else {
1532 concurrent_mark()->cancel();
1533 stop_concurrent_marking();
1534
1535 if (process_references()) {
1536 // Abandon reference processing right away: pre-cleaning must have failed.
1537 ReferenceProcessor *rp = ref_processor();
1538 rp->disable_discovery();
1539 rp->abandon_partial_discovery();
1540 rp->verify_no_references_recorded();
1541 }
1542 }
1543 }
1544
1545 void ShenandoahHeap::op_final_evac() {
1546 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1547
1548 set_evacuation_in_progress(false);
1549
1550 retire_and_reset_gclabs();
1551
1552 if (ShenandoahVerify) {
1553 verifier()->verify_after_evacuation();
1554 }
1555
1556 if (VerifyAfterGC) {
1557 Universe::verify();
1558 }
1559 }
1560
1561 void ShenandoahHeap::op_conc_evac() {
1562 ShenandoahEvacuationTask task(this, _collection_set, true);
1563 workers()->run_task(&task);
1564 }
1565
1566 void ShenandoahHeap::op_stw_evac() {
1567 ShenandoahEvacuationTask task(this, _collection_set, false);
1568 workers()->run_task(&task);
1569 }
1570
1571 void ShenandoahHeap::op_updaterefs() {
1572 update_heap_references(true);
1573 }
1574
1575 void ShenandoahHeap::op_cleanup() {
1576 free_set()->recycle_trash();
1577 }
1578
1579 void ShenandoahHeap::op_reset() {
1580 reset_mark_bitmap();
1581 }
1582
1583 void ShenandoahHeap::op_preclean() {
1584 concurrent_mark()->preclean_weak_refs();
1585 }
1586
1587 void ShenandoahHeap::op_init_traversal() {
1588 traversal_gc()->init_traversal_collection();
1589 }
1590
1591 void ShenandoahHeap::op_traversal() {
1592 traversal_gc()->concurrent_traversal_collection();
1593 }
1594
1595 void ShenandoahHeap::op_final_traversal() {
1596 traversal_gc()->final_traversal_collection();
1597 }
1598
1599 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1600 ShenandoahMetricsSnapshot metrics;
1601 metrics.snap_before();
1602
1603 full_gc()->do_it(cause);
1604 if (UseTLAB) {
1605 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1606 resize_all_tlabs();
1607 }
1608
1609 metrics.snap_after();
1610 metrics.print();
1611
1612 if (metrics.is_good_progress("Full GC")) {
1613 _progress_last_gc.set();
1614 } else {
1615 // Nothing to do. Tell the allocation path that we have failed to make
1616 // progress, and it can finally fail.
1617 _progress_last_gc.unset();
1618 }
1619 }
1620
1621 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1622 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1623 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1624 // some phase, we have to upgrade the Degenerate GC to Full GC.
1625
1626 clear_cancelled_gc();
1627
1628 ShenandoahMetricsSnapshot metrics;
1629 metrics.snap_before();
1630
1631 switch (point) {
1632 case _degenerated_traversal:
1633 {
1634 // Drop the collection set. Note: this leaves some already forwarded objects
1635 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1636 // workarounds in ShenandoahTraversalHeuristics.
1637
1638 ShenandoahHeapLocker locker(lock());
1639 collection_set()->clear_current_index();
1640 for (size_t i = 0; i < collection_set()->count(); i++) {
1641 ShenandoahHeapRegion* r = collection_set()->next();
1642 r->make_regular_bypass();
1643 }
1644 collection_set()->clear();
1645 }
1646 op_final_traversal();
1647 op_cleanup();
1648 return;
1649
1650 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1651 // but enters it at different points, depending on which concurrent phase had
1652 // degenerated.
1653
1654 case _degenerated_outside_cycle:
1655 // We have degenerated from outside the cycle, which means something is bad with
1656 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1657 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1658 // we can do the most aggressive degen cycle, which includes processing references and
1659 // class unloading, unless those features are explicitly disabled.
1660 //
1661 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1662 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1663 set_process_references(heuristics()->can_process_references());
1664 set_unload_classes(heuristics()->can_unload_classes());
1665
1666 if (heuristics()->can_do_traversal_gc()) {
1667 // Not possible to degenerate from here, upgrade to Full GC right away.
1668 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1669 op_degenerated_fail();
1670 return;
1671 }
1672
1673 op_reset();
1674
1675 op_init_mark();
1676 if (cancelled_gc()) {
1677 op_degenerated_fail();
1678 return;
1679 }
1680
1681 case _degenerated_mark:
1682 op_final_mark();
1683 if (cancelled_gc()) {
1684 op_degenerated_fail();
1685 return;
1686 }
1687
1688 op_cleanup();
1689
1690 case _degenerated_evac:
1691 // If heuristics thinks we should do the cycle, this flag would be set,
1692 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1693 if (is_evacuation_in_progress()) {
1694
1695 // Degeneration under oom-evac protocol might have left some objects in
1696 // collection set un-evacuated. Restart evacuation from the beginning to
1697 // capture all objects. For all the objects that are already evacuated,
1698 // it would be a simple check, which is supposed to be fast. This is also
1699 // safe to do even without degeneration, as CSet iterator is at beginning
1700 // in preparation for evacuation anyway.
1701 collection_set()->clear_current_index();
1702
1703 op_stw_evac();
1704 if (cancelled_gc()) {
1705 op_degenerated_fail();
1706 return;
1707 }
1708 }
1709
1710 // If heuristics thinks we should do the cycle, this flag would be set,
1711 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1712 if (has_forwarded_objects()) {
1713 op_init_updaterefs();
1714 if (cancelled_gc()) {
1715 op_degenerated_fail();
1716 return;
1717 }
1718 }
1719
1720 case _degenerated_updaterefs:
1721 if (has_forwarded_objects()) {
1722 op_final_updaterefs();
1723 if (cancelled_gc()) {
1724 op_degenerated_fail();
1725 return;
1726 }
1727 }
1728
1729 op_cleanup();
1730 break;
1731
1732 default:
1733 ShouldNotReachHere();
1734 }
1735
1736 if (ShenandoahVerify) {
1737 verifier()->verify_after_degenerated();
1738 }
1739
1740 if (VerifyAfterGC) {
1741 Universe::verify();
1742 }
1743
1744 metrics.snap_after();
1745 metrics.print();
1746
1747 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1748 // because that probably means the heap is overloaded and/or fragmented.
1749 if (!metrics.is_good_progress("Degenerated GC")) {
1750 _progress_last_gc.unset();
1751 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1752 op_degenerated_futile();
1753 } else {
1754 _progress_last_gc.set();
1755 }
1756 }
1757
1758 void ShenandoahHeap::op_degenerated_fail() {
1759 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1760 shenandoah_policy()->record_degenerated_upgrade_to_full();
1761 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1762 }
1763
1764 void ShenandoahHeap::op_degenerated_futile() {
1765 shenandoah_policy()->record_degenerated_upgrade_to_full();
1766 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1767 }
1768
1769 void ShenandoahHeap::stop_concurrent_marking() {
1770 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1771 if (!cancelled_gc()) {
1772 // If we needed to update refs, and concurrent marking has been cancelled,
1773 // we need to finish updating references.
1774 set_has_forwarded_objects(false);
1775 mark_complete_marking_context();
1776 }
1777 set_concurrent_mark_in_progress(false);
1778 }
1779
1780 void ShenandoahHeap::force_satb_flush_all_threads() {
1781 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1782 // No need to flush SATBs
1783 return;
1784 }
1785
1786 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1787 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1788 }
1789 // The threads are not "acquiring" their thread-local data, but it does not
1790 // hurt to "release" the updates here anyway.
1791 OrderAccess::fence();
1792 }
1793
1794 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1795 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1796 ShenandoahThreadLocalData::set_gc_state(t, state);
1797 }
1798 }
1799
1800 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1801 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1802 _gc_state.set_cond(mask, value);
1803 set_gc_state_all_threads(_gc_state.raw_value());
1804 }
1805
1806 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1807 set_gc_state_mask(MARKING, in_progress);
1808 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1809 }
1810
1811 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1812 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1813 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1814 }
1815
1816 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1817 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1818 set_gc_state_mask(EVACUATION, in_progress);
1819 }
1820
1821 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1822 // Initialize Brooks pointer for the next object
1823 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1824 ShenandoahBrooksPointer::initialize(oop(result));
1825 return result;
1826 }
1827
1828 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1829 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1830 }
1831
1832 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1833 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1834 }
1835
1836 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1837 if (CompressedOops::is_null(obj)) {
1838 return false;
1839 }
1840 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1841 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1842 return _mark_context->is_marked(obj);
1843 }
1844
1845 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1846 if (CompressedOops::is_null(obj)) {
1847 return false;
1848 }
1849 shenandoah_assert_not_forwarded(NULL, obj);
1850 return _mark_context->is_marked(obj);
1851 }
1852
1853 void ShenandoahHeap::ref_processing_init() {
1854 assert(_max_workers > 0, "Sanity");
1855
1856 _ref_processor =
1857 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1858 ParallelRefProcEnabled, // MT processing
1859 _max_workers, // Degree of MT processing
1860 true, // MT discovery
1861 _max_workers, // Degree of MT discovery
1862 false, // Reference discovery is not atomic
1863 NULL, // No closure, should be installed before use
1864 true); // Scale worker threads
1865
1866 shenandoah_assert_rp_isalive_not_installed();
1867 }
1868
1869 GCTracer* ShenandoahHeap::tracer() {
1870 return shenandoah_policy()->tracer();
1871 }
1872
1873 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1874 return _free_set->used();
1875 }
1876
1877 bool ShenandoahHeap::try_cancel_gc() {
1878 while (true) {
1879 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1880 if (prev == CANCELLABLE) return true;
1881 else if (prev == CANCELLED) return false;
1882 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1883 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1884 {
1885 // We need to provide a safepoint here, otherwise we might
1886 // spin forever if a SP is pending.
1887 ThreadBlockInVM sp(JavaThread::current());
1888 SpinPause();
1889 }
1890 }
1891 }
1892
1893 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1894 if (try_cancel_gc()) {
1895 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1896 log_info(gc)("%s", msg.buffer());
1897 Events::log(Thread::current(), "%s", msg.buffer());
1898 }
1899 }
1900
1901 uint ShenandoahHeap::max_workers() {
1902 return _max_workers;
1903 }
1904
1905 void ShenandoahHeap::stop() {
1906 // The shutdown sequence should be able to terminate when GC is running.
1907
1908 // Step 0. Notify policy to disable event recording.
1909 _shenandoah_policy->record_shutdown();
1910
1911 // Step 1. Notify control thread that we are in shutdown.
1912 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1913 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1914 control_thread()->prepare_for_graceful_shutdown();
1915
1916 // Step 2. Notify GC workers that we are cancelling GC.
1917 cancel_gc(GCCause::_shenandoah_stop_vm);
1918
1919 // Step 3. Wait until GC worker exits normally.
1920 control_thread()->stop();
1921
1922 // Step 4. Stop String Dedup thread if it is active
1923 if (ShenandoahStringDedup::is_enabled()) {
1924 ShenandoahStringDedup::stop();
1925 }
1926 }
1927
1928 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1929 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1930
1931 ShenandoahGCPhase root_phase(full_gc ?
1932 ShenandoahPhaseTimings::full_gc_purge :
1933 ShenandoahPhaseTimings::purge);
1934
1935 ShenandoahIsAliveSelector alive;
1936 BoolObjectClosure* is_alive = alive.is_alive_closure();
1937
1938 bool purged_class;
1939
1940 // Unload classes and purge SystemDictionary.
1941 {
1942 ShenandoahGCPhase phase(full_gc ?
1943 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1944 ShenandoahPhaseTimings::purge_class_unload);
1945 purged_class = SystemDictionary::do_unloading(gc_timer());
1946 }
1947
1948 {
1949 ShenandoahGCPhase phase(full_gc ?
1950 ShenandoahPhaseTimings::full_gc_purge_par :
1951 ShenandoahPhaseTimings::purge_par);
1952 uint active = _workers->active_workers();
1953 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1954 _workers->run_task(&unlink_task);
1955 }
1956
1957 {
1958 ShenandoahGCPhase phase(full_gc ?
1959 ShenandoahPhaseTimings::full_gc_purge_cldg :
1960 ShenandoahPhaseTimings::purge_cldg);
1961 ClassLoaderDataGraph::purge();
1962 }
1963 }
1964
1965 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1966 set_gc_state_mask(HAS_FORWARDED, cond);
1967 }
1968
1969 void ShenandoahHeap::set_process_references(bool pr) {
1970 _process_references.set_cond(pr);
1971 }
1972
1973 void ShenandoahHeap::set_unload_classes(bool uc) {
1974 _unload_classes.set_cond(uc);
1975 }
1976
1977 bool ShenandoahHeap::process_references() const {
1978 return _process_references.is_set();
1979 }
1980
1981 bool ShenandoahHeap::unload_classes() const {
1982 return _unload_classes.is_set();
1983 }
1984
1985 address ShenandoahHeap::in_cset_fast_test_addr() {
1986 ShenandoahHeap* heap = ShenandoahHeap::heap();
1987 assert(heap->collection_set() != NULL, "Sanity");
1988 return (address) heap->collection_set()->biased_map_address();
1989 }
1990
1991 address ShenandoahHeap::cancelled_gc_addr() {
1992 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1993 }
1994
1995 address ShenandoahHeap::gc_state_addr() {
1996 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1997 }
1998
1999 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2000 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2001 }
2002
2003 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2004 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2005 }
2006
2007 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2008 _degenerated_gc_in_progress.set_cond(in_progress);
2009 }
2010
2011 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2012 _full_gc_in_progress.set_cond(in_progress);
2013 }
2014
2015 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2016 assert (is_full_gc_in_progress(), "should be");
2017 _full_gc_move_in_progress.set_cond(in_progress);
2018 }
2019
2020 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2021 set_gc_state_mask(UPDATEREFS, in_progress);
2022 }
2023
2024 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2025 ShenandoahCodeRoots::add_nmethod(nm);
2026 }
2027
2028 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2029 ShenandoahCodeRoots::remove_nmethod(nm);
2030 }
2031
2032 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2033 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2034 ShenandoahHeapLocker locker(lock());
2035 heap_region_containing(o)->make_pinned();
2036 return o;
2037 }
2038
2039 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2040 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2041 ShenandoahHeapLocker locker(lock());
2042 heap_region_containing(o)->make_unpinned();
2043 }
2044
2045 GCTimer* ShenandoahHeap::gc_timer() const {
2046 return _gc_timer;
2047 }
2048
2049 #ifdef ASSERT
2050 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2051 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2052
2053 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2054 if (UseDynamicNumberOfGCThreads ||
2055 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2056 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2057 } else {
2058 // Use ParallelGCThreads inside safepoints
2059 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2060 }
2061 } else {
2062 if (UseDynamicNumberOfGCThreads ||
2063 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2064 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2065 } else {
2066 // Use ConcGCThreads outside safepoints
2067 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2068 }
2069 }
2070 }
2071 #endif
2072
2073 ShenandoahVerifier* ShenandoahHeap::verifier() {
2074 guarantee(ShenandoahVerify, "Should be enabled");
2075 assert (_verifier != NULL, "sanity");
2076 return _verifier;
2077 }
2078
2079 template<class T>
2080 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2081 private:
2082 T cl;
2083 ShenandoahHeap* _heap;
2084 ShenandoahRegionIterator* _regions;
2085 bool _concurrent;
2086 public:
2087 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2088 AbstractGangTask("Concurrent Update References Task"),
2089 cl(T()),
2090 _heap(ShenandoahHeap::heap()),
2091 _regions(regions),
2092 _concurrent(concurrent) {
2093 }
2094
2095 void work(uint worker_id) {
2096 if (_concurrent) {
2097 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2098 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2099 do_work();
2100 } else {
2101 ShenandoahParallelWorkerSession worker_session(worker_id);
2102 do_work();
2103 }
2104 }
2105
2106 private:
2107 void do_work() {
2108 ShenandoahHeapRegion* r = _regions->next();
2109 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2110 while (r != NULL) {
2111 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2112 assert (top_at_start_ur >= r->bottom(), "sanity");
2113 if (r->is_active() && !r->is_cset()) {
2114 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2115 }
2116 if (ShenandoahPacing) {
2117 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2118 }
2119 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2120 return;
2121 }
2122 r = _regions->next();
2123 }
2124 }
2125 };
2126
2127 void ShenandoahHeap::update_heap_references(bool concurrent) {
2128 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2129 workers()->run_task(&task);
2130 }
2131
2132 void ShenandoahHeap::op_init_updaterefs() {
2133 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2134
2135 set_evacuation_in_progress(false);
2136
2137 retire_and_reset_gclabs();
2138
2139 if (ShenandoahVerify) {
2140 verifier()->verify_before_updaterefs();
2141 }
2142
2143 set_update_refs_in_progress(true);
2144 make_parsable(true);
2145 for (uint i = 0; i < num_regions(); i++) {
2146 ShenandoahHeapRegion* r = get_region(i);
2147 r->set_concurrent_iteration_safe_limit(r->top());
2148 }
2149
2150 // Reset iterator.
2151 _update_refs_iterator.reset();
2152
2153 if (ShenandoahPacing) {
2154 pacer()->setup_for_updaterefs();
2155 }
2156 }
2157
2158 void ShenandoahHeap::op_final_updaterefs() {
2159 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2160
2161 // Check if there is left-over work, and finish it
2162 if (_update_refs_iterator.has_next()) {
2163 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2164
2165 // Finish updating references where we left off.
2166 clear_cancelled_gc();
2167 update_heap_references(false);
2168 }
2169
2170 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2171 // everything. On degenerated paths, cancelled gc would not be set anyway.
2172 if (cancelled_gc()) {
2173 clear_cancelled_gc();
2174 }
2175 assert(!cancelled_gc(), "Should have been done right before");
2176
2177 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2178 ShenandoahPhaseTimings::degen_gc_update_roots:
2179 ShenandoahPhaseTimings::final_update_refs_roots);
2180
2181 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2182
2183 trash_cset_regions();
2184 set_has_forwarded_objects(false);
2185 set_update_refs_in_progress(false);
2186
2187 if (ShenandoahVerify) {
2188 verifier()->verify_after_updaterefs();
2189 }
2190
2191 if (VerifyAfterGC) {
2192 Universe::verify();
2193 }
2194
2195 {
2196 ShenandoahHeapLocker locker(lock());
2197 _free_set->rebuild();
2198 }
2199 }
2200
2201 #ifdef ASSERT
2202 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2203 _lock.assert_owned_by_current_thread();
2204 }
2205
2206 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2207 _lock.assert_not_owned_by_current_thread();
2208 }
2209
2210 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2211 _lock.assert_owned_by_current_thread_or_safepoint();
2212 }
2213 #endif
2214
2215 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2216 print_on(st);
2217 print_heap_regions_on(st);
2218 }
2219
2220 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2221 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2222
2223 size_t regions_from = _bitmap_regions_per_slice * slice;
2224 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2225 for (size_t g = regions_from; g < regions_to; g++) {
2226 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2227 if (skip_self && g == r->region_number()) continue;
2228 if (get_region(g)->is_committed()) {
2229 return true;
2230 }
2231 }
2232 return false;
2233 }
2234
2235 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2236 assert_heaplock_owned_by_current_thread();
2237
2238 if (is_bitmap_slice_committed(r, true)) {
2239 // Some other region from the group is already committed, meaning the bitmap
2240 // slice is already committed, we exit right away.
2241 return true;
2242 }
2243
2244 // Commit the bitmap slice:
2245 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2246 size_t off = _bitmap_bytes_per_slice * slice;
2247 size_t len = _bitmap_bytes_per_slice;
2248 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2249 return false;
2250 }
2251 return true;
2252 }
2253
2254 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2255 assert_heaplock_owned_by_current_thread();
2256
2257 if (is_bitmap_slice_committed(r, true)) {
2258 // Some other region from the group is still committed, meaning the bitmap
2259 // slice is should stay committed, exit right away.
2260 return true;
2261 }
2262
2263 // Uncommit the bitmap slice:
2264 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2265 size_t off = _bitmap_bytes_per_slice * slice;
2266 size_t len = _bitmap_bytes_per_slice;
2267 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2268 return false;
2269 }
2270 return true;
2271 }
2272
2273 void ShenandoahHeap::safepoint_synchronize_begin() {
2274 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2275 SuspendibleThreadSet::synchronize();
2276 }
2277 }
2278
2279 void ShenandoahHeap::safepoint_synchronize_end() {
2280 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2281 SuspendibleThreadSet::desynchronize();
2282 }
2283 }
2284
2285 void ShenandoahHeap::vmop_entry_init_mark() {
2286 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2287 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2288 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2289
2290 try_inject_alloc_failure();
2291 VM_ShenandoahInitMark op;
2292 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2293 }
2294
2295 void ShenandoahHeap::vmop_entry_final_mark() {
2296 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2297 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2298 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2299
2300 try_inject_alloc_failure();
2301 VM_ShenandoahFinalMarkStartEvac op;
2302 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2303 }
2304
2305 void ShenandoahHeap::vmop_entry_final_evac() {
2306 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2307 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2308 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2309
2310 VM_ShenandoahFinalEvac op;
2311 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2312 }
2313
2314 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2315 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2316 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2317 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2318
2319 try_inject_alloc_failure();
2320 VM_ShenandoahInitUpdateRefs op;
2321 VMThread::execute(&op);
2322 }
2323
2324 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2325 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2326 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2327 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2328
2329 try_inject_alloc_failure();
2330 VM_ShenandoahFinalUpdateRefs op;
2331 VMThread::execute(&op);
2332 }
2333
2334 void ShenandoahHeap::vmop_entry_init_traversal() {
2335 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2336 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2337 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2338
2339 try_inject_alloc_failure();
2340 VM_ShenandoahInitTraversalGC op;
2341 VMThread::execute(&op);
2342 }
2343
2344 void ShenandoahHeap::vmop_entry_final_traversal() {
2345 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2346 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2347 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2348
2349 try_inject_alloc_failure();
2350 VM_ShenandoahFinalTraversalGC op;
2351 VMThread::execute(&op);
2352 }
2353
2354 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2355 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2356 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2357 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2358
2359 try_inject_alloc_failure();
2360 VM_ShenandoahFullGC op(cause);
2361 VMThread::execute(&op);
2362 }
2363
2364 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2365 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2366 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2367 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2368
2369 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2370 VMThread::execute(°enerated_gc);
2371 }
2372
2373 void ShenandoahHeap::entry_init_mark() {
2374 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2375 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2376 const char* msg = init_mark_event_message();
2377 GCTraceTime(Info, gc) time(msg, gc_timer());
2378 EventMark em("%s", msg);
2379
2380 ShenandoahWorkerScope scope(workers(),
2381 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2382 "init marking");
2383
2384 op_init_mark();
2385 }
2386
2387 void ShenandoahHeap::entry_final_mark() {
2388 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2389 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2390 const char* msg = final_mark_event_message();
2391 GCTraceTime(Info, gc) time(msg, gc_timer());
2392 EventMark em("%s", msg);
2393
2394 ShenandoahWorkerScope scope(workers(),
2395 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2396 "final marking");
2397
2398 op_final_mark();
2399 }
2400
2401 void ShenandoahHeap::entry_final_evac() {
2402 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2403 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2404 static const char* msg = "Pause Final Evac";
2405 GCTraceTime(Info, gc) time(msg, gc_timer());
2406 EventMark em("%s", msg);
2407
2408 op_final_evac();
2409 }
2410
2411 void ShenandoahHeap::entry_init_updaterefs() {
2412 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2413 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2414
2415 static const char* msg = "Pause Init Update Refs";
2416 GCTraceTime(Info, gc) time(msg, gc_timer());
2417 EventMark em("%s", msg);
2418
2419 // No workers used in this phase, no setup required
2420
2421 op_init_updaterefs();
2422 }
2423
2424 void ShenandoahHeap::entry_final_updaterefs() {
2425 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2426 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2427
2428 static const char* msg = "Pause Final Update Refs";
2429 GCTraceTime(Info, gc) time(msg, gc_timer());
2430 EventMark em("%s", msg);
2431
2432 ShenandoahWorkerScope scope(workers(),
2433 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2434 "final reference update");
2435
2436 op_final_updaterefs();
2437 }
2438
2439 void ShenandoahHeap::entry_init_traversal() {
2440 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2441 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2442
2443 static const char* msg = "Pause Init Traversal";
2444 GCTraceTime(Info, gc) time(msg, gc_timer());
2445 EventMark em("%s", msg);
2446
2447 ShenandoahWorkerScope scope(workers(),
2448 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2449 "init traversal");
2450
2451 op_init_traversal();
2452 }
2453
2454 void ShenandoahHeap::entry_final_traversal() {
2455 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2456 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2457
2458 static const char* msg = "Pause Final Traversal";
2459 GCTraceTime(Info, gc) time(msg, gc_timer());
2460 EventMark em("%s", msg);
2461
2462 ShenandoahWorkerScope scope(workers(),
2463 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2464 "final traversal");
2465
2466 op_final_traversal();
2467 }
2468
2469 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2470 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2471 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2472
2473 static const char* msg = "Pause Full";
2474 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2475 EventMark em("%s", msg);
2476
2477 ShenandoahWorkerScope scope(workers(),
2478 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2479 "full gc");
2480
2481 op_full(cause);
2482 }
2483
2484 void ShenandoahHeap::entry_degenerated(int point) {
2485 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2486 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2487
2488 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2489 const char* msg = degen_event_message(dpoint);
2490 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2491 EventMark em("%s", msg);
2492
2493 ShenandoahWorkerScope scope(workers(),
2494 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2495 "stw degenerated gc");
2496
2497 set_degenerated_gc_in_progress(true);
2498 op_degenerated(dpoint);
2499 set_degenerated_gc_in_progress(false);
2500 }
2501
2502 void ShenandoahHeap::entry_mark() {
2503 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2504
2505 const char* msg = conc_mark_event_message();
2506 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2507 EventMark em("%s", msg);
2508
2509 ShenandoahWorkerScope scope(workers(),
2510 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2511 "concurrent marking");
2512
2513 try_inject_alloc_failure();
2514 op_mark();
2515 }
2516
2517 void ShenandoahHeap::entry_evac() {
2518 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2519 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2520
2521 static const char* msg = "Concurrent evacuation";
2522 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2523 EventMark em("%s", msg);
2524
2525 ShenandoahWorkerScope scope(workers(),
2526 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2527 "concurrent evacuation");
2528
2529 try_inject_alloc_failure();
2530 op_conc_evac();
2531 }
2532
2533 void ShenandoahHeap::entry_updaterefs() {
2534 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2535
2536 static const char* msg = "Concurrent update references";
2537 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2538 EventMark em("%s", msg);
2539
2540 ShenandoahWorkerScope scope(workers(),
2541 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2542 "concurrent reference update");
2543
2544 try_inject_alloc_failure();
2545 op_updaterefs();
2546 }
2547 void ShenandoahHeap::entry_cleanup() {
2548 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2549
2550 static const char* msg = "Concurrent cleanup";
2551 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2552 EventMark em("%s", msg);
2553
2554 // This phase does not use workers, no need for setup
2555
2556 try_inject_alloc_failure();
2557 op_cleanup();
2558 }
2559
2560 void ShenandoahHeap::entry_reset() {
2561 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2562
2563 static const char* msg = "Concurrent reset";
2564 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2565 EventMark em("%s", msg);
2566
2567 ShenandoahWorkerScope scope(workers(),
2568 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2569 "concurrent reset");
2570
2571 try_inject_alloc_failure();
2572 op_reset();
2573 }
2574
2575 void ShenandoahHeap::entry_preclean() {
2576 if (ShenandoahPreclean && process_references()) {
2577 static const char* msg = "Concurrent precleaning";
2578 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2579 EventMark em("%s", msg);
2580
2581 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2582
2583 ShenandoahWorkerScope scope(workers(),
2584 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2585 "concurrent preclean",
2586 /* check_workers = */ false);
2587
2588 try_inject_alloc_failure();
2589 op_preclean();
2590 }
2591 }
2592
2593 void ShenandoahHeap::entry_traversal() {
2594 static const char* msg = "Concurrent traversal";
2595 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2596 EventMark em("%s", msg);
2597
2598 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2599
2600 ShenandoahWorkerScope scope(workers(),
2601 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2602 "concurrent traversal");
2603
2604 try_inject_alloc_failure();
2605 op_traversal();
2606 }
2607
2608 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2609 static const char *msg = "Concurrent uncommit";
2610 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2611 EventMark em("%s", msg);
2612
2613 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2614
2615 op_uncommit(shrink_before);
2616 }
2617
2618 void ShenandoahHeap::try_inject_alloc_failure() {
2619 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2620 _inject_alloc_failure.set();
2621 os::naked_short_sleep(1);
2622 if (cancelled_gc()) {
2623 log_info(gc)("Allocation failure was successfully injected");
2624 }
2625 }
2626 }
2627
2628 bool ShenandoahHeap::should_inject_alloc_failure() {
2629 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2630 }
2631
2632 void ShenandoahHeap::initialize_serviceability() {
2633 _memory_pool = new ShenandoahMemoryPool(this);
2634 _cycle_memory_manager.add_pool(_memory_pool);
2635 _stw_memory_manager.add_pool(_memory_pool);
2636 }
2637
2638 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2639 GrowableArray<GCMemoryManager*> memory_managers(2);
2640 memory_managers.append(&_cycle_memory_manager);
2641 memory_managers.append(&_stw_memory_manager);
2642 return memory_managers;
2643 }
2644
2645 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2646 GrowableArray<MemoryPool*> memory_pools(1);
2647 memory_pools.append(_memory_pool);
2648 return memory_pools;
2649 }
2650
2651 MemoryUsage ShenandoahHeap::memory_usage() {
2652 return _memory_pool->get_memory_usage();
2653 }
2654
2655 void ShenandoahHeap::enter_evacuation() {
2656 _oom_evac_handler.enter_evacuation();
2657 }
2658
2659 void ShenandoahHeap::leave_evacuation() {
2660 _oom_evac_handler.leave_evacuation();
2661 }
2662
2663 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2664 _heap(ShenandoahHeap::heap()),
2665 _index(0) {}
2666
2667 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2668 _heap(heap),
2669 _index(0) {}
2670
2671 void ShenandoahRegionIterator::reset() {
2672 _index = 0;
2673 }
2674
2675 bool ShenandoahRegionIterator::has_next() const {
2676 return _index < _heap->num_regions();
2677 }
2678
2679 char ShenandoahHeap::gc_state() const {
2680 return _gc_state.raw_value();
2681 }
2682
2683 void ShenandoahHeap::deduplicate_string(oop str) {
2684 assert(java_lang_String::is_instance(str), "invariant");
2685
2686 if (ShenandoahStringDedup::is_enabled()) {
2687 ShenandoahStringDedup::deduplicate(str);
2688 }
2689 }
2690
2691 const char* ShenandoahHeap::init_mark_event_message() const {
2692 bool update_refs = has_forwarded_objects();
2693 bool proc_refs = process_references();
2694 bool unload_cls = unload_classes();
2695
2696 if (update_refs && proc_refs && unload_cls) {
2697 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2698 } else if (update_refs && proc_refs) {
2699 return "Pause Init Mark (update refs) (process weakrefs)";
2700 } else if (update_refs && unload_cls) {
2701 return "Pause Init Mark (update refs) (unload classes)";
2702 } else if (proc_refs && unload_cls) {
2703 return "Pause Init Mark (process weakrefs) (unload classes)";
2704 } else if (update_refs) {
2705 return "Pause Init Mark (update refs)";
2706 } else if (proc_refs) {
2707 return "Pause Init Mark (process weakrefs)";
2708 } else if (unload_cls) {
2709 return "Pause Init Mark (unload classes)";
2710 } else {
2711 return "Pause Init Mark";
2712 }
2713 }
2714
2715 const char* ShenandoahHeap::final_mark_event_message() const {
2716 bool update_refs = has_forwarded_objects();
2717 bool proc_refs = process_references();
2718 bool unload_cls = unload_classes();
2719
2720 if (update_refs && proc_refs && unload_cls) {
2721 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2722 } else if (update_refs && proc_refs) {
2723 return "Pause Final Mark (update refs) (process weakrefs)";
2724 } else if (update_refs && unload_cls) {
2725 return "Pause Final Mark (update refs) (unload classes)";
2726 } else if (proc_refs && unload_cls) {
2727 return "Pause Final Mark (process weakrefs) (unload classes)";
2728 } else if (update_refs) {
2729 return "Pause Final Mark (update refs)";
2730 } else if (proc_refs) {
2731 return "Pause Final Mark (process weakrefs)";
2732 } else if (unload_cls) {
2733 return "Pause Final Mark (unload classes)";
2734 } else {
2735 return "Pause Final Mark";
2736 }
2737 }
2738
2739 const char* ShenandoahHeap::conc_mark_event_message() const {
2740 bool update_refs = has_forwarded_objects();
2741 bool proc_refs = process_references();
2742 bool unload_cls = unload_classes();
2743
2744 if (update_refs && proc_refs && unload_cls) {
2745 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2746 } else if (update_refs && proc_refs) {
2747 return "Concurrent marking (update refs) (process weakrefs)";
2748 } else if (update_refs && unload_cls) {
2749 return "Concurrent marking (update refs) (unload classes)";
2750 } else if (proc_refs && unload_cls) {
2751 return "Concurrent marking (process weakrefs) (unload classes)";
2752 } else if (update_refs) {
2753 return "Concurrent marking (update refs)";
2754 } else if (proc_refs) {
2755 return "Concurrent marking (process weakrefs)";
2756 } else if (unload_cls) {
2757 return "Concurrent marking (unload classes)";
2758 } else {
2759 return "Concurrent marking";
2760 }
2761 }
2762
2763 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2764 switch (point) {
2765 case _degenerated_unset:
2766 return "Pause Degenerated GC (<UNSET>)";
2767 case _degenerated_traversal:
2768 return "Pause Degenerated GC (Traversal)";
2769 case _degenerated_outside_cycle:
2770 return "Pause Degenerated GC (Outside of Cycle)";
2771 case _degenerated_mark:
2772 return "Pause Degenerated GC (Mark)";
2773 case _degenerated_evac:
2774 return "Pause Degenerated GC (Evacuation)";
2775 case _degenerated_updaterefs:
2776 return "Pause Degenerated GC (Update Refs)";
2777 default:
2778 ShouldNotReachHere();
2779 return "ERROR";
2780 }
2781 }
2782
2783 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2784 #ifdef ASSERT
2785 assert(_liveness_cache != NULL, "sanity");
2786 assert(worker_id < _max_workers, "sanity");
2787 for (uint i = 0; i < num_regions(); i++) {
2788 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2789 }
2790 #endif
2791 return _liveness_cache[worker_id];
2792 }
2793
2794 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2795 assert(worker_id < _max_workers, "sanity");
2796 assert(_liveness_cache != NULL, "sanity");
2797 jushort* ld = _liveness_cache[worker_id];
2798 for (uint i = 0; i < num_regions(); i++) {
2799 ShenandoahHeapRegion* r = get_region(i);
2800 jushort live = ld[i];
2801 if (live > 0) {
2802 r->increase_live_data_gc_words(live);
2803 ld[i] = 0;
2804 }
2805 }
2806 }
2807
2808 size_t ShenandoahHeap::obj_size(oop obj) const {
2809 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2810 }
2811
2812 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2813 return ShenandoahBrooksPointer::byte_size();
2814 }
2815
2816 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2817 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2818 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2819 }