1 /*
2 * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
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/parallelCleaning.hpp"
30
31 #include "gc/shenandoah/brooksPointer.hpp"
32 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
33 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
34 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
35 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
36 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentThread.hpp"
38 #include "gc/shenandoah/shenandoahFreeSet.hpp"
39 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
40 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
41 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
42 #include "gc/shenandoah/shenandoahHumongous.hpp"
43 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
44 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
45 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
46 #include "gc/shenandoah/shenandoahPartialGC.hpp"
47 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
48 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
49
50 #include "runtime/vmThread.hpp"
51 #include "services/mallocTracker.hpp"
52
53 SCMUpdateRefsClosure::SCMUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
54
55 #ifdef ASSERT
56 template <class T>
57 void AssertToSpaceClosure::do_oop_nv(T* p) {
58 T o = oopDesc::load_heap_oop(p);
59 if (! oopDesc::is_null(o)) {
60 oop obj = oopDesc::decode_heap_oop_not_null(o);
61 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
62 "need to-space object here obj: "PTR_FORMAT" , rb(obj): "PTR_FORMAT", p: "PTR_FORMAT,
63 p2i(obj), p2i(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), p2i(p));
64 }
65 }
66
67 void AssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
68 void AssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
69 #endif
70
71 const char* ShenandoahHeap::name() const {
72 return "Shenandoah";
73 }
74
75 void ShenandoahHeap::print_heap_locations(HeapWord* start, HeapWord* end) {
76 HeapWord* cur = NULL;
77 for (cur = start; cur < end; cur++) {
78 tty->print_cr(PTR_FORMAT" : "PTR_FORMAT, p2i(cur), p2i(*((HeapWord**) cur)));
79 }
80 }
81
82 class ShenandoahPretouchTask : public AbstractGangTask {
83 private:
84 ShenandoahHeapRegionSet* _regions;
85 const size_t _bitmap_size;
86 const size_t _page_size;
87 char* _bitmap0_base;
88 char* _bitmap1_base;
89 public:
90 ShenandoahPretouchTask(ShenandoahHeapRegionSet* regions,
91 char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
92 size_t page_size) :
93 AbstractGangTask("Shenandoah PreTouch",
94 Universe::is_fully_initialized() ? GCId::current_raw() :
95 // During VM initialization there is
96 // no GC cycle that this task can be
97 // associated with.
98 GCId::undefined()),
99 _bitmap0_base(bitmap0_base),
100 _bitmap1_base(bitmap1_base),
101 _regions(regions),
102 _bitmap_size(bitmap_size),
103 _page_size(page_size) {
104 _regions->clear_current_index();
105 };
106
107 virtual void work(uint worker_id) {
108 ShenandoahHeapRegion* r = _regions->claim_next();
109 while (r != NULL) {
110 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
111 r->region_number(), p2i(r->bottom()), p2i(r->end()));
112 os::pretouch_memory(r->bottom(), r->end(), _page_size);
113
114 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / CMBitMap::heap_map_factor();
115 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / CMBitMap::heap_map_factor();
116 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
117
118 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
119 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
120 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
121
122 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
123 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
124 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
125
126 r = _regions->claim_next();
127 }
128 }
129 };
130
131 jint ShenandoahHeap::initialize() {
132 CollectedHeap::pre_initialize();
133
134 BrooksPointer::initial_checks();
135
136 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
137 size_t max_byte_size = collector_policy()->max_heap_byte_size();
138
139 Universe::check_alignment(max_byte_size,
140 ShenandoahHeapRegion::region_size_bytes(),
141 "shenandoah heap");
142 Universe::check_alignment(init_byte_size,
143 ShenandoahHeapRegion::region_size_bytes(),
144 "shenandoah heap");
145
146 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
147 Arguments::conservative_max_heap_alignment());
148 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
149
150 set_barrier_set(new ShenandoahBarrierSet(this));
151 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
152 _storage.initialize(pgc_rs, init_byte_size);
153
154 _num_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
155 _max_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
156 _initialSize = _num_regions * ShenandoahHeapRegion::region_size_bytes();
157 size_t regionSizeWords = ShenandoahHeapRegion::region_size_bytes() / HeapWordSize;
158 assert(init_byte_size == _initialSize, "tautology");
159 _ordered_regions = new ShenandoahHeapRegionSet(_max_regions);
160 _collection_set = new ShenandoahCollectionSet(_max_regions);
161 _free_regions = new ShenandoahFreeSet(_max_regions);
162
163 // Initialize fast collection set test structure.
164 _in_cset_fast_test_length = _max_regions;
165 _in_cset_fast_test_base =
166 NEW_C_HEAP_ARRAY(bool, _in_cset_fast_test_length, mtGC);
167 _in_cset_fast_test = _in_cset_fast_test_base -
168 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_shift());
169
170 _next_top_at_mark_starts_base =
171 NEW_C_HEAP_ARRAY(HeapWord*, _max_regions, mtGC);
172 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
173 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_shift());
174
175 _complete_top_at_mark_starts_base =
176 NEW_C_HEAP_ARRAY(HeapWord*, _max_regions, mtGC);
177 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
178 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_shift());
179
180 size_t i = 0;
181 for (i = 0; i < _num_regions; i++) {
182 _in_cset_fast_test_base[i] = false; // Not in cset
183 HeapWord* bottom = (HeapWord*) pgc_rs.base() + regionSizeWords * i;
184 _complete_top_at_mark_starts_base[i] = bottom;
185 _next_top_at_mark_starts_base[i] = bottom;
186 }
187
188 {
189 ShenandoahHeapLock lock(this);
190 for (i = 0; i < _num_regions; i++) {
191 ShenandoahHeapRegion* current = new ShenandoahHeapRegion(this, (HeapWord*) pgc_rs.base() +
192 regionSizeWords * i, regionSizeWords, i);
193 _free_regions->add_region(current);
194 _ordered_regions->add_region(current);
195 }
196 }
197 assert(((size_t) _ordered_regions->active_regions()) == _num_regions, "");
198 _first_region = _ordered_regions->get(0);
199 assert((((size_t) base()) &
200 (ShenandoahHeapRegion::region_size_bytes() - 1)) == 0,
201 "misaligned heap: "PTR_FORMAT, p2i(base()));
202
203 if (log_is_enabled(Trace, gc, region)) {
204 ResourceMark rm;
205 outputStream* out = Log(gc, region)::trace_stream();
206 log_trace(gc, region)("All Regions");
207 _ordered_regions->print(out);
208 log_trace(gc, region)("Free Regions");
209 _free_regions->print(out);
210 }
211
212 // The call below uses stuff (the SATB* things) that are in G1, but probably
213 // belong into a shared location.
214 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
215 SATB_Q_FL_lock,
216 20 /*G1SATBProcessCompletedThreshold */,
217 Shared_SATB_Q_lock);
218
219 // Reserve space for prev and next bitmap.
220 _bitmap_size = CMBitMap::compute_size(heap_rs.size());
221 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
222
223 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
224
225 ReservedSpace bitmap0(_bitmap_size, page_size);
226 os::commit_memory_or_exit(bitmap0.base(), bitmap0.size(), false, "couldn't allocate mark bitmap");
227 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
228 MemRegion bitmap_region0 = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
229
230 ReservedSpace bitmap1(_bitmap_size, page_size);
231 os::commit_memory_or_exit(bitmap1.base(), bitmap1.size(), false, "couldn't allocate mark bitmap");
232 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
233 MemRegion bitmap_region1 = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
234
235 if (ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix)) {
236 ReservedSpace verify_bitmap(_bitmap_size, page_size);
237 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
238 "couldn't allocate verification bitmap");
239 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
240 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
241 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
242 }
243
244 if (ShenandoahAlwaysPreTouch) {
245 assert (!AlwaysPreTouch, "Should have been overridden");
246
247 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
248 // before initialize() below zeroes it with initializing thread. For any given region,
249 // we touch the region and the corresponding bitmaps from the same thread.
250
251 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
252 _ordered_regions->count(), page_size);
253 ShenandoahPretouchTask cl(_ordered_regions, bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
254 _workers->run_task(&cl);
255 }
256
257 _mark_bit_map0.initialize(_heap_region, bitmap_region0);
258 _complete_mark_bit_map = &_mark_bit_map0;
259
260 _mark_bit_map1.initialize(_heap_region, bitmap_region1);
261 _next_mark_bit_map = &_mark_bit_map1;
262
263 _connection_matrix = new ShenandoahConnectionMatrix(_max_regions);
264 _partial_gc = new ShenandoahPartialGC(this, _max_regions);
265
266 _monitoring_support = new ShenandoahMonitoringSupport(this);
267
268 _concurrent_gc_thread = new ShenandoahConcurrentThread();
269
270 ShenandoahMarkCompact::initialize();
271
272 return JNI_OK;
273 }
274
275 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
276 CollectedHeap(),
277 _shenandoah_policy(policy),
278 _concurrent_mark_in_progress(0),
279 _evacuation_in_progress(0),
280 _full_gc_in_progress(false),
281 _update_refs_in_progress(false),
282 _free_regions(NULL),
283 _collection_set(NULL),
284 _bytes_allocated_since_cm(0),
285 _bytes_allocated_during_cm(0),
286 _allocated_last_gc(0),
287 _used_start_gc(0),
288 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
289 _ref_processor(NULL),
290 _in_cset_fast_test(NULL),
291 _in_cset_fast_test_base(NULL),
292 _next_top_at_mark_starts(NULL),
293 _next_top_at_mark_starts_base(NULL),
294 _complete_top_at_mark_starts(NULL),
295 _complete_top_at_mark_starts_base(NULL),
296 _mark_bit_map0(),
297 _mark_bit_map1(),
298 _connection_matrix(NULL),
299 _cancelled_concgc(false),
300 _need_update_refs(false),
301 _need_reset_bitmaps(false),
302 _heap_lock(0),
303 #ifdef ASSERT
304 _heap_lock_owner(NULL),
305 #endif
306 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer())
307
308 {
309 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
310 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
311 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
312
313 _scm = new ShenandoahConcurrentMark();
314 _used = 0;
315
316 _max_workers = MAX2(_max_workers, 1U);
317 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
318 /* are_GC_task_threads */true,
319 /* are_ConcurrentGC_threads */false);
320 if (_workers == NULL) {
321 vm_exit_during_initialization("Failed necessary allocation.");
322 } else {
323 _workers->initialize_workers();
324 }
325 }
326
327 class ResetNextBitmapTask : public AbstractGangTask {
328 private:
329 ShenandoahHeapRegionSet* _regions;
330
331 public:
332 ResetNextBitmapTask(ShenandoahHeapRegionSet* regions) :
333 AbstractGangTask("Parallel Reset Bitmap Task"),
334 _regions(regions) {
335 _regions->clear_current_index();
336 }
337
338 void work(uint worker_id) {
339 ShenandoahHeapRegion* region = _regions->claim_next();
340 ShenandoahHeap* heap = ShenandoahHeap::heap();
341 while (region != NULL) {
342 HeapWord* bottom = region->bottom();
343 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
344 if (top > bottom) {
345 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
346 }
347 region = _regions->claim_next();
348 }
349 }
350 };
351
352 void ShenandoahHeap::reset_next_mark_bitmap(WorkGang* workers) {
353 ResetNextBitmapTask task = ResetNextBitmapTask(_ordered_regions);
354 workers->run_task(&task);
355 }
356
357 class ResetCompleteBitmapTask : public AbstractGangTask {
358 private:
359 ShenandoahHeapRegionSet* _regions;
360
361 public:
362 ResetCompleteBitmapTask(ShenandoahHeapRegionSet* regions) :
363 AbstractGangTask("Parallel Reset Bitmap Task"),
364 _regions(regions) {
365 _regions->clear_current_index();
366 }
367
368 void work(uint worker_id) {
369 ShenandoahHeapRegion* region = _regions->claim_next();
370 ShenandoahHeap* heap = ShenandoahHeap::heap();
371 while (region != NULL) {
372 HeapWord* bottom = region->bottom();
373 HeapWord* top = heap->complete_top_at_mark_start(region->bottom());
374 if (top > bottom) {
375 heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
376 }
377 region = _regions->claim_next();
378 }
379 }
380 };
381
382 void ShenandoahHeap::reset_complete_mark_bitmap(WorkGang* workers) {
383 ResetCompleteBitmapTask task = ResetCompleteBitmapTask(_ordered_regions);
384 workers->run_task(&task);
385 }
386
387 bool ShenandoahHeap::is_next_bitmap_clear() {
388 HeapWord* start = _ordered_regions->bottom();
389 HeapWord* end = _ordered_regions->end();
390 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
391 }
392
393 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
394 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
395 }
396
397 void ShenandoahHeap::print_on(outputStream* st) const {
398 st->print("Shenandoah Heap");
399 st->print(" total = " SIZE_FORMAT " K, used " SIZE_FORMAT " K ", capacity()/ K, used() /K);
400 st->print(" [" PTR_FORMAT ", " PTR_FORMAT ") ",
401 p2i(reserved_region().start()),
402 p2i(reserved_region().end()));
403 st->print("Region size = " SIZE_FORMAT "K ", ShenandoahHeapRegion::region_size_bytes() / K);
404 if (_concurrent_mark_in_progress) {
405 st->print("marking ");
406 }
407 if (_evacuation_in_progress) {
408 st->print("evacuating ");
409 }
410 if (cancelled_concgc()) {
411 st->print("cancelled ");
412 }
413 st->print("\n");
414
415 // Adapted from VirtualSpace::print_on(), which is non-PRODUCT only
416 st->print ("Virtual space:");
417 if (_storage.special()) st->print(" (pinned in memory)");
418 st->cr();
419 st->print_cr(" - committed: " SIZE_FORMAT, _storage.committed_size());
420 st->print_cr(" - reserved: " SIZE_FORMAT, _storage.reserved_size());
421 st->print_cr(" - [low, high]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", p2i(_storage.low()), p2i(_storage.high()));
422 st->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", p2i(_storage.low_boundary()), p2i(_storage.high_boundary()));
423
424 if (Verbose) {
425 print_heap_regions(st);
426 }
427 }
428
429 class InitGCLABClosure : public ThreadClosure {
430 public:
431 void do_thread(Thread* thread) {
432 thread->gclab().initialize(true);
433 }
434 };
435
436 void ShenandoahHeap::post_initialize() {
437 if (UseTLAB) {
438 // This is a very tricky point in VM lifetime. We cannot easily call Threads::threads_do
439 // here, because some system threads (VMThread, WatcherThread, etc) are not yet available.
440 // Their initialization should be handled separately. Is we miss some threads here,
441 // then any other TLAB-related activity would fail with asserts.
442
443 InitGCLABClosure init_gclabs;
444 {
445 MutexLocker ml(Threads_lock);
446 for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
447 init_gclabs.do_thread(thread);
448 }
449 }
450 gc_threads_do(&init_gclabs);
451
452 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
453 // Now, we will let WorkGang to initialize gclab when new worker is created.
454 _workers->set_initialize_gclab();
455 }
456
457 _scm->initialize(_max_workers);
458
459 ref_processing_init();
460 }
461
462 class CalculateUsedRegionClosure : public ShenandoahHeapRegionClosure {
463 size_t sum;
464 public:
465
466 CalculateUsedRegionClosure() {
467 sum = 0;
468 }
469
470 bool doHeapRegion(ShenandoahHeapRegion* r) {
471 sum = sum + r->used();
472 return false;
473 }
474
475 size_t getResult() { return sum;}
476 };
477
478 size_t ShenandoahHeap::calculateUsed() {
479 CalculateUsedRegionClosure cl;
480 heap_region_iterate(&cl);
481 return cl.getResult();
482 }
483
484 void ShenandoahHeap::verify_heap_size_consistency() {
485
486 assert(calculateUsed() == used(),
487 "heap used size must be consistent heap-used: "SIZE_FORMAT" regions-used: "SIZE_FORMAT, used(), calculateUsed());
488 }
489
490 size_t ShenandoahHeap::used() const {
491 OrderAccess::acquire();
492 return _used;
493 }
494
495 void ShenandoahHeap::increase_used(size_t bytes) {
496 assert_heaplock_or_safepoint();
497 _used += bytes;
498 }
499
500 void ShenandoahHeap::set_used(size_t bytes) {
501 assert_heaplock_or_safepoint();
502 _used = bytes;
503 }
504
505 void ShenandoahHeap::decrease_used(size_t bytes) {
506 assert_heaplock_or_safepoint();
507 assert(_used >= bytes, "never decrease heap size by more than we've left");
508 _used -= bytes;
509 }
510
511 size_t ShenandoahHeap::capacity() const {
512 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
513 }
514
515 bool ShenandoahHeap::is_maximal_no_gc() const {
516 Unimplemented();
517 return true;
518 }
519
520 size_t ShenandoahHeap::max_capacity() const {
521 return _max_regions * ShenandoahHeapRegion::region_size_bytes();
522 }
523
524 size_t ShenandoahHeap::min_capacity() const {
525 return _initialSize;
526 }
527
528 VirtualSpace* ShenandoahHeap::storage() const {
529 return (VirtualSpace*) &_storage;
530 }
531
532 bool ShenandoahHeap::is_in(const void* p) const {
533 HeapWord* heap_base = (HeapWord*) base();
534 HeapWord* last_region_end = heap_base + (ShenandoahHeapRegion::region_size_bytes() / HeapWordSize) * _num_regions;
535 return p >= heap_base && p < last_region_end;
536 }
537
538 bool ShenandoahHeap::is_scavengable(const void* p) {
539 return true;
540 }
541
542 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
543 // Retain tlab and allocate object in shared space if
544 // the amount free in the tlab is too large to discard.
545 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
546 thread->gclab().record_slow_allocation(size);
547 return NULL;
548 }
549
550 // Discard gclab and allocate a new one.
551 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
552 size_t new_gclab_size = thread->gclab().compute_size(size);
553
554 thread->gclab().clear_before_allocation();
555
556 if (new_gclab_size == 0) {
557 return NULL;
558 }
559
560 // Allocate a new GCLAB...
561 HeapWord* obj = allocate_new_gclab(new_gclab_size);
562 if (obj == NULL) {
563 return NULL;
564 }
565
566 if (ZeroTLAB) {
567 // ..and clear it.
568 Copy::zero_to_words(obj, new_gclab_size);
569 } else {
570 // ...and zap just allocated object.
571 #ifdef ASSERT
572 // Skip mangling the space corresponding to the object header to
573 // ensure that the returned space is not considered parsable by
574 // any concurrent GC thread.
575 size_t hdr_size = oopDesc::header_size();
576 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
577 #endif // ASSERT
578 }
579 thread->gclab().fill(obj, obj + size, new_gclab_size);
580 return obj;
581 }
582
583 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
584 return allocate_new_tlab(word_size, false);
585 }
586
587 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
588 return allocate_new_tlab(word_size, true);
589 }
590
591 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size, bool evacuating) {
592 HeapWord* result = allocate_memory(word_size, evacuating);
593
594 if (result != NULL) {
595 assert(! in_collection_set(result), "Never allocate in dirty region");
596 _bytes_allocated_since_cm += word_size * HeapWordSize;
597
598 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
599
600 }
601 return result;
602 }
603
604 ShenandoahHeap* ShenandoahHeap::heap() {
605 CollectedHeap* heap = Universe::heap();
606 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
607 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
608 return (ShenandoahHeap*) heap;
609 }
610
611 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
612 CollectedHeap* heap = Universe::heap();
613 return (ShenandoahHeap*) heap;
614 }
615
616 HeapWord* ShenandoahHeap::allocate_memory_work(size_t word_size) {
617
618 ShenandoahHeapLock heap_lock(this);
619
620 HeapWord* result = allocate_memory_under_lock(word_size);
621 size_t grow_by = (word_size * HeapWordSize + ShenandoahHeapRegion::region_size_bytes() - 1) / ShenandoahHeapRegion::region_size_bytes();
622
623 while (result == NULL && _num_regions + grow_by <= _max_regions) {
624 grow_heap_by(grow_by);
625 result = allocate_memory_under_lock(word_size);
626 }
627
628 return result;
629 }
630
631 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, bool evacuating) {
632 HeapWord* result = NULL;
633 result = allocate_memory_work(word_size);
634
635 if (!evacuating) {
636 // Allocation failed, try full-GC, then retry allocation.
637 //
638 // It might happen that one of the threads requesting allocation would unblock
639 // way later after full-GC happened, only to fail the second allocation, because
640 // other threads have already depleted the free storage. In this case, a better
641 // strategy would be to try full-GC again.
642 //
643 // Lacking the way to detect progress from "collect" call, we are left with blindly
644 // retrying for some bounded number of times.
645 // TODO: Poll if Full GC made enough progress to warrant retry.
646 int tries = 0;
647 while ((result == NULL) && (tries++ < ShenandoahFullGCTries)) {
648 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing full GC, try %d",
649 p2i(Thread::current()), word_size * HeapWordSize, tries);
650 collect(GCCause::_allocation_failure);
651 result = allocate_memory_work(word_size);
652 }
653 }
654
655 // Only update monitoring counters when not calling from a write-barrier.
656 // Otherwise we might attempt to grab the Service_lock, which we must
657 // not do when coming from a write-barrier (because the thread might
658 // already hold the Compile_lock).
659 if (! evacuating) {
660 monitoring_support()->update_counters();
661 }
662
663 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
664 word_size, p2i(result), Thread::current()->osthread()->thread_id());
665
666 return result;
667 }
668
669 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size) {
670 assert_heaplock_owned_by_current_thread();
671
672 if (word_size * HeapWordSize > ShenandoahHeapRegion::region_size_bytes()) {
673 return allocate_large_memory(word_size);
674 }
675
676 // Not enough memory in free region set.
677 // Coming out of full GC, it is possible that there is not
678 // free region available, so current_index may not be valid.
679 if (word_size * HeapWordSize > _free_regions->capacity()) return NULL;
680
681 ShenandoahHeapRegion* my_current_region = _free_regions->current_no_humongous();
682
683 if (my_current_region == NULL) {
684 return NULL; // No more room to make a new region. OOM.
685 }
686 assert(my_current_region != NULL, "should have a region at this point");
687
688 #ifdef ASSERT
689 if (in_collection_set(my_current_region)) {
690 print_heap_regions();
691 }
692 #endif
693 assert(! in_collection_set(my_current_region), "never get targetted regions in free-lists");
694 assert(! my_current_region->is_humongous(), "never attempt to allocate from humongous object regions");
695
696 HeapWord* result = my_current_region->allocate(word_size);
697
698 while (result == NULL) {
699 // 2nd attempt. Try next region.
700 _free_regions->increase_used(my_current_region->free());
701 ShenandoahHeapRegion* next_region = _free_regions->next_no_humongous();
702 assert(next_region != my_current_region, "must not get current again");
703 my_current_region = next_region;
704
705 if (my_current_region == NULL) {
706 return NULL; // No more room to make a new region. OOM.
707 }
708 assert(my_current_region != NULL, "should have a region at this point");
709 assert(! in_collection_set(my_current_region), "never get targetted regions in free-lists");
710 assert(! my_current_region->is_humongous(), "never attempt to allocate from humongous object regions");
711 result = my_current_region->allocate(word_size);
712 }
713
714 my_current_region->increase_live_data_words(word_size);
715 increase_used(word_size * HeapWordSize);
716 _free_regions->increase_used(word_size * HeapWordSize);
717 return result;
718 }
719
720 HeapWord* ShenandoahHeap::allocate_large_memory(size_t words) {
721 assert_heaplock_owned_by_current_thread();
722
723 size_t required_regions = ShenandoahHumongous::required_regions(words * HeapWordSize);
724 if (required_regions > _max_regions) return NULL;
725
726 ShenandoahHeapRegion* r = _free_regions->allocate_contiguous(required_regions);
727
728 HeapWord* result = NULL;
729
730 if (r != NULL) {
731 result = r->bottom();
732
733 log_debug(gc, humongous)("allocating humongous object of size: "SIZE_FORMAT" KB at location "PTR_FORMAT" in start region "SIZE_FORMAT,
734 (words * HeapWordSize) / K, p2i(result), r->region_number());
735 } else {
736 log_debug(gc, humongous)("allocating humongous object of size: "SIZE_FORMAT" KB at location "PTR_FORMAT" failed",
737 (words * HeapWordSize) / K, p2i(result));
738 }
739
740
741 return result;
742
743 }
744
745 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
746 bool* gc_overhead_limit_was_exceeded) {
747
748 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), false);
749 HeapWord* result = filler + BrooksPointer::word_size();
750 if (filler != NULL) {
751 BrooksPointer::initialize(oop(result));
752 _bytes_allocated_since_cm += size * HeapWordSize;
753
754 assert(! in_collection_set(result), "never allocate in targetted region");
755 return result;
756 } else {
757 /*
758 tty->print_cr("Out of memory. Requested number of words: "SIZE_FORMAT" used heap: "INT64_FORMAT", bytes allocated since last CM: "INT64_FORMAT,
759 size, used(), _bytes_allocated_since_cm);
760 {
761 print_heap_regions();
762 tty->print("Printing "SIZE_FORMAT" free regions:\n", _free_regions->count());
763 _free_regions->print();
764 }
765 */
766 return NULL;
767 }
768 }
769
770 class ParallelEvacuateRegionObjectClosure : public ObjectClosure {
771 private:
772 ShenandoahHeap* _heap;
773 Thread* _thread;
774 public:
775 ParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
776 _heap(heap), _thread(Thread::current()) {
777 }
778
779 void do_object(oop p) {
780
781 log_develop_trace(gc, compaction)("Calling ParallelEvacuateRegionObjectClosure on "PTR_FORMAT" of size %d\n", p2i((HeapWord*) p), p->size());
782
783 assert(_heap->is_marked_complete(p), "expect only marked objects");
784 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p))) {
785 bool evac;
786 _heap->evacuate_object(p, _thread, evac);
787 }
788 }
789 };
790
791 #ifdef ASSERT
792 class VerifyEvacuatedObjectClosure : public ObjectClosure {
793
794 public:
795
796 void do_object(oop p) {
797 if (ShenandoahHeap::heap()->is_marked_complete(p)) {
798 oop p_prime = oopDesc::bs()->read_barrier(p);
799 assert(! oopDesc::unsafe_equals(p, p_prime), "Should point to evacuated copy");
800 if (p->klass() != p_prime->klass()) {
801 tty->print_cr("copy has different class than original:");
802 p->klass()->print_on(tty);
803 p_prime->klass()->print_on(tty);
804 }
805 assert(p->klass() == p_prime->klass(), "Should have the same class p: "PTR_FORMAT", p_prime: "PTR_FORMAT, p2i(p), p2i(p_prime));
806 // assert(p->mark() == p_prime->mark(), "Should have the same mark");
807 assert(p->size() == p_prime->size(), "Should be the same size");
808 assert(oopDesc::unsafe_equals(p_prime, oopDesc::bs()->read_barrier(p_prime)), "One forward once");
809 }
810 }
811 };
812
813 void ShenandoahHeap::verify_evacuated_region(ShenandoahHeapRegion* from_region) {
814 VerifyEvacuatedObjectClosure verify_evacuation;
815 marked_object_iterate(from_region, &verify_evacuation);
816 }
817 #endif
818
819 void ShenandoahHeap::parallel_evacuate_region(ShenandoahHeapRegion* from_region) {
820
821 assert(from_region->has_live(), "all-garbage regions are reclaimed earlier");
822
823 ParallelEvacuateRegionObjectClosure evacuate_region(this);
824
825 marked_object_iterate(from_region, &evacuate_region);
826
827 #ifdef ASSERT
828 if (ShenandoahVerify && ! cancelled_concgc()) {
829 verify_evacuated_region(from_region);
830 }
831 #endif
832 }
833
834 class ParallelEvacuationTask : public AbstractGangTask {
835 private:
836 ShenandoahHeap* _sh;
837 ShenandoahCollectionSet* _cs;
838
839 public:
840 ParallelEvacuationTask(ShenandoahHeap* sh,
841 ShenandoahCollectionSet* cs) :
842 AbstractGangTask("Parallel Evacuation Task"),
843 _cs(cs),
844 _sh(sh) {}
845
846 void work(uint worker_id) {
847
848 ShenandoahHeapRegion* from_hr = _cs->claim_next();
849
850 while (from_hr != NULL) {
851 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
852 worker_id,
853 from_hr->region_number());
854
855 assert(from_hr->has_live(), "all-garbage regions are reclaimed early");
856 _sh->parallel_evacuate_region(from_hr);
857
858 if (_sh->cancelled_concgc()) {
859 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT "\n", from_hr->region_number());
860 break;
861 }
862 from_hr = _cs->claim_next();
863 }
864 }
865 };
866
867 class RecycleDirtyRegionsClosure: public ShenandoahHeapRegionClosure {
868 private:
869 ShenandoahHeap* _heap;
870 size_t _bytes_reclaimed;
871 public:
872 RecycleDirtyRegionsClosure() : _heap(ShenandoahHeap::heap()) {}
873
874 bool doHeapRegion(ShenandoahHeapRegion* r) {
875
876 assert (! _heap->cancelled_concgc(), "no recycling after cancelled marking");
877
878 if (_heap->in_collection_set(r)) {
879 log_develop_trace(gc, region)("Recycling region " SIZE_FORMAT ":", r->region_number());
880 _heap->decrease_used(r->used());
881 _bytes_reclaimed += r->used();
882 r->recycle();
883 }
884
885 return false;
886 }
887 size_t bytes_reclaimed() { return _bytes_reclaimed;}
888 void clear_bytes_reclaimed() {_bytes_reclaimed = 0;}
889 };
890
891 void ShenandoahHeap::recycle_dirty_regions() {
892 RecycleDirtyRegionsClosure cl;
893 cl.clear_bytes_reclaimed();
894
895 heap_region_iterate(&cl);
896
897 _shenandoah_policy->record_bytes_reclaimed(cl.bytes_reclaimed());
898 if (! cancelled_concgc()) {
899 clear_cset_fast_test();
900 }
901 }
902
903 ShenandoahFreeSet* ShenandoahHeap::free_regions() {
904 return _free_regions;
905 }
906
907 void ShenandoahHeap::print_heap_regions(outputStream* st) const {
908 _ordered_regions->print(st);
909 }
910
911 class PrintAllRefsOopClosure: public ExtendedOopClosure {
912 private:
913 int _index;
914 const char* _prefix;
915
916 public:
917 PrintAllRefsOopClosure(const char* prefix) : _index(0), _prefix(prefix) {}
918
919 private:
920 template <class T>
921 inline void do_oop_work(T* p) {
922 oop o = oopDesc::load_decode_heap_oop(p);
923 if (o != NULL) {
924 if (ShenandoahHeap::heap()->is_in(o) && o->is_oop()) {
925 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT")-> "PTR_FORMAT" (marked: %s) (%s "PTR_FORMAT")",
926 _prefix, _index,
927 p2i(p), p2i(o),
928 BOOL_TO_STR(ShenandoahHeap::heap()->is_marked_complete(o)),
929 o->klass()->internal_name(), p2i(o->klass()));
930 } else {
931 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT" dirty -> "PTR_FORMAT" (not in heap, possibly corrupted or dirty)",
932 _prefix, _index,
933 p2i(p), p2i(o));
934 }
935 } else {
936 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT") -> "PTR_FORMAT, _prefix, _index, p2i(p), p2i((HeapWord*) o));
937 }
938 _index++;
939 }
940
941 public:
942 void do_oop(oop* p) {
943 do_oop_work(p);
944 }
945
946 void do_oop(narrowOop* p) {
947 do_oop_work(p);
948 }
949
950 };
951
952 class PrintAllRefsObjectClosure : public ObjectClosure {
953 const char* _prefix;
954
955 public:
956 PrintAllRefsObjectClosure(const char* prefix) : _prefix(prefix) {}
957
958 void do_object(oop p) {
959 if (ShenandoahHeap::heap()->is_in(p)) {
960 tty->print_cr("%s object "PTR_FORMAT" (marked: %s) (%s "PTR_FORMAT") refers to:",
961 _prefix, p2i(p),
962 BOOL_TO_STR(ShenandoahHeap::heap()->is_marked_complete(p)),
963 p->klass()->internal_name(), p2i(p->klass()));
964 PrintAllRefsOopClosure cl(_prefix);
965 p->oop_iterate(&cl);
966 }
967 }
968 };
969
970 void ShenandoahHeap::print_all_refs(const char* prefix) {
971 tty->print_cr("printing all references in the heap");
972 tty->print_cr("root references:");
973
974 ensure_parsability(false);
975
976 PrintAllRefsOopClosure cl(prefix);
977 roots_iterate(&cl);
978
979 tty->print_cr("heap references:");
980 PrintAllRefsObjectClosure cl2(prefix);
981 object_iterate(&cl2);
982 }
983
984 class VerifyAfterMarkingOopClosure: public ExtendedOopClosure {
985 private:
986 ShenandoahHeap* _heap;
987
988 public:
989 VerifyAfterMarkingOopClosure() :
990 _heap(ShenandoahHeap::heap()) { }
991
992 private:
993 template <class T>
994 inline void do_oop_work(T* p) {
995 oop o = oopDesc::load_decode_heap_oop(p);
996 if (o != NULL) {
997 if (! _heap->is_marked_complete(o)) {
998 _heap->print_heap_regions();
999 _heap->print_all_refs("post-mark");
1000 tty->print_cr("oop not marked, although referrer is marked: "PTR_FORMAT": in_heap: %s, is_marked: %s",
1001 p2i((HeapWord*) o), BOOL_TO_STR(_heap->is_in(o)), BOOL_TO_STR(_heap->is_marked_complete(o)));
1002 _heap->print_heap_locations((HeapWord*) o, (HeapWord*) o + o->size());
1003
1004 tty->print_cr("oop class: %s", o->klass()->internal_name());
1005 if (_heap->is_in(p)) {
1006 oop referrer = oop(_heap->heap_region_containing(p)->block_start_const(p));
1007 tty->print_cr("Referrer starts at addr "PTR_FORMAT, p2i((HeapWord*) referrer));
1008 referrer->print();
1009 _heap->print_heap_locations((HeapWord*) referrer, (HeapWord*) referrer + referrer->size());
1010 }
1011 tty->print_cr("heap region containing object:");
1012 _heap->heap_region_containing(o)->print();
1013 tty->print_cr("heap region containing referrer:");
1014 _heap->heap_region_containing(p)->print();
1015 tty->print_cr("heap region containing forwardee:");
1016 _heap->heap_region_containing(oopDesc::bs()->read_barrier(o))->print();
1017 }
1018 assert(o->is_oop(), "oop must be an oop");
1019 assert(Metaspace::contains(o->klass()), "klass pointer must go to metaspace");
1020 if (! oopDesc::unsafe_equals(o, oopDesc::bs()->read_barrier(o))) {
1021 tty->print_cr("oops has forwardee: p: "PTR_FORMAT" (%s), o = "PTR_FORMAT" (%s), new-o: "PTR_FORMAT" (%s)",
1022 p2i(p),
1023 BOOL_TO_STR(_heap->in_collection_set(p)),
1024 p2i(o),
1025 BOOL_TO_STR(_heap->in_collection_set(o)),
1026 p2i((HeapWord*) oopDesc::bs()->read_barrier(o)),
1027 BOOL_TO_STR(_heap->in_collection_set(oopDesc::bs()->read_barrier(o))));
1028 tty->print_cr("oop class: %s", o->klass()->internal_name());
1029 }
1030 assert(oopDesc::unsafe_equals(o, oopDesc::bs()->read_barrier(o)), "oops must not be forwarded");
1031 assert(! _heap->in_collection_set(o), "references must not point to dirty heap regions");
1032 assert(_heap->is_marked_complete(o), "live oops must be marked current");
1033 }
1034 }
1035
1036 public:
1037 void do_oop(oop* p) {
1038 do_oop_work(p);
1039 }
1040
1041 void do_oop(narrowOop* p) {
1042 do_oop_work(p);
1043 }
1044
1045 };
1046
1047 void ShenandoahHeap::verify_heap_after_marking() {
1048
1049 verify_heap_size_consistency();
1050
1051 log_trace(gc)("verifying heap after marking");
1052
1053 VerifyAfterMarkingOopClosure cl;
1054 roots_iterate(&cl);
1055 ObjectToOopClosure objs(&cl);
1056 object_iterate(&objs);
1057 }
1058
1059
1060 void ShenandoahHeap::reclaim_humongous_region_at(ShenandoahHeapRegion* r) {
1061 assert(r->is_humongous_start(), "reclaim regions starting with the first one");
1062
1063 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size());
1064 size_t size = humongous_obj->size() + BrooksPointer::word_size();
1065 size_t required_regions = ShenandoahHumongous::required_regions(size * HeapWordSize);
1066 size_t index = r->region_number();
1067
1068
1069 assert(!r->has_live(), "liveness must be zero");
1070
1071 for(size_t i = 0; i < required_regions; i++) {
1072
1073 ShenandoahHeapRegion* region = _ordered_regions->get(index++);
1074
1075 assert((region->is_humongous_start() || region->is_humongous_continuation()),
1076 "expect correct humongous start or continuation");
1077
1078 if (log_is_enabled(Debug, gc, humongous)) {
1079 log_debug(gc, humongous)("reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
1080 ResourceMark rm;
1081 outputStream* out = Log(gc, humongous)::debug_stream();
1082 region->print_on(out);
1083 }
1084
1085 region->recycle();
1086 ShenandoahHeap::heap()->decrease_used(ShenandoahHeapRegion::region_size_bytes());
1087 }
1088 }
1089
1090 class ShenandoahReclaimHumongousRegionsClosure : public ShenandoahHeapRegionClosure {
1091
1092 bool doHeapRegion(ShenandoahHeapRegion* r) {
1093 ShenandoahHeap* heap = ShenandoahHeap::heap();
1094
1095 if (r->is_humongous_start()) {
1096 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size());
1097 if (! heap->is_marked_complete(humongous_obj)) {
1098
1099 heap->reclaim_humongous_region_at(r);
1100 }
1101 }
1102 return false;
1103 }
1104 };
1105
1106 #ifdef ASSERT
1107 class CheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1108 bool doHeapRegion(ShenandoahHeapRegion* r) {
1109 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1110 return false;
1111 }
1112 };
1113 #endif
1114
1115 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1116 assert(_ordered_regions->get(0)->region_number() == 0, "FIXME CHF. FIXME CHF!");
1117
1118 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1119
1120 if (!cancelled_concgc()) {
1121
1122 recycle_dirty_regions();
1123
1124 ensure_parsability(true);
1125
1126 if (UseShenandoahMatrix && PrintShenandoahMatrix) {
1127 outputStream* log = Log(gc)::info_stream();
1128 connection_matrix()->print_on(log);
1129 }
1130
1131 if (ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix)) {
1132 verify_heap_reachable_at_safepoint();
1133 }
1134
1135 #ifdef ASSERT
1136 if (ShenandoahVerify) {
1137 verify_heap_after_marking();
1138 }
1139 #endif
1140
1141 // NOTE: This needs to be done during a stop the world pause, because
1142 // putting regions into the collection set concurrently with Java threads
1143 // will create a race. In particular, acmp could fail because when we
1144 // resolve the first operand, the containing region might not yet be in
1145 // the collection set, and thus return the original oop. When the 2nd
1146 // operand gets resolved, the region could be in the collection set
1147 // and the oop gets evacuated. If both operands have originally been
1148 // the same, we get false negatives.
1149
1150 {
1151 ShenandoahHeapLock lock(this);
1152 _collection_set->clear();
1153 _free_regions->clear();
1154
1155 ShenandoahReclaimHumongousRegionsClosure reclaim;
1156 heap_region_iterate(&reclaim);
1157
1158 #ifdef ASSERT
1159 CheckCollectionSetClosure ccsc;
1160 _ordered_regions->heap_region_iterate(&ccsc);
1161 #endif
1162
1163 _shenandoah_policy->choose_collection_set(_collection_set);
1164
1165 _shenandoah_policy->choose_free_set(_free_regions);
1166 }
1167
1168 _bytes_allocated_since_cm = 0;
1169
1170 Universe::update_heap_info_at_gc();
1171 }
1172 }
1173
1174
1175 class RetireTLABClosure : public ThreadClosure {
1176 private:
1177 bool _retire;
1178
1179 public:
1180 RetireTLABClosure(bool retire) : _retire(retire) {
1181 }
1182
1183 void do_thread(Thread* thread) {
1184 thread->gclab().make_parsable(_retire);
1185 }
1186 };
1187
1188 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1189 if (UseTLAB) {
1190 CollectedHeap::ensure_parsability(retire_tlabs);
1191 RetireTLABClosure cl(retire_tlabs);
1192 Threads::threads_do(&cl);
1193 }
1194 }
1195
1196 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
1197 private:
1198 ShenandoahHeap* _heap;
1199 Thread* _thread;
1200 public:
1201 ShenandoahEvacuateUpdateRootsClosure() :
1202 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
1203 }
1204
1205 private:
1206 template <class T>
1207 void do_oop_work(T* p) {
1208 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
1209
1210 T o = oopDesc::load_heap_oop(p);
1211 if (! oopDesc::is_null(o)) {
1212 oop obj = oopDesc::decode_heap_oop_not_null(o);
1213 if (_heap->in_collection_set(obj)) {
1214 assert(_heap->is_marked_complete(obj), "only evacuate marked objects %d %d",
1215 _heap->is_marked_complete(obj), _heap->is_marked_complete(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)));
1216 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1217 if (oopDesc::unsafe_equals(resolved, obj)) {
1218 bool evac;
1219 resolved = _heap->evacuate_object(obj, _thread, evac);
1220 }
1221 oopDesc::encode_store_heap_oop(p, resolved);
1222 }
1223 }
1224 #ifdef ASSERT
1225 else {
1226 // tty->print_cr("not updating root at: "PTR_FORMAT" with object: "PTR_FORMAT", is_in_heap: %s, is_in_cset: %s, is_marked: %s",
1227 // p2i(p),
1228 // p2i((HeapWord*) obj),
1229 // BOOL_TO_STR(_heap->is_in(obj)),
1230 // BOOL_TO_STR(_heap->in_cset_fast_test(obj)),
1231 // BOOL_TO_STR(_heap->is_marked_complete(obj)));
1232 }
1233 #endif
1234 }
1235
1236 public:
1237 void do_oop(oop* p) {
1238 do_oop_work(p);
1239 }
1240 void do_oop(narrowOop* p) {
1241 do_oop_work(p);
1242 }
1243 };
1244
1245 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1246 ShenandoahRootEvacuator* _rp;
1247 public:
1248
1249 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1250 AbstractGangTask("Shenandoah evacuate and update roots"),
1251 _rp(rp)
1252 {
1253 // Nothing else to do.
1254 }
1255
1256 void work(uint worker_id) {
1257 ShenandoahEvacuateUpdateRootsClosure cl;
1258 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1259
1260 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1261 }
1262 };
1263
1264 class ShenandoahFixRootsTask : public AbstractGangTask {
1265 ShenandoahRootEvacuator* _rp;
1266 public:
1267
1268 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1269 AbstractGangTask("Shenandoah update roots"),
1270 _rp(rp)
1271 {
1272 // Nothing else to do.
1273 }
1274
1275 void work(uint worker_id) {
1276 SCMUpdateRefsClosure cl;
1277 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1278
1279 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1280 }
1281 };
1282 void ShenandoahHeap::evacuate_and_update_roots() {
1283
1284 COMPILER2_PRESENT(DerivedPointerTable::clear());
1285
1286 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1287
1288 {
1289 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahCollectorPolicy::init_evac);
1290 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1291 workers()->run_task(&roots_task);
1292 }
1293
1294 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1295
1296 if (cancelled_concgc()) {
1297 // If initial evacuation has been cancelled, we need to update all references
1298 // after all workers have finished. Otherwise we might run into the following problem:
1299 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1300 // GC thread 2 evacuates the same object X to to-space
1301 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1302 // clear() and update_pointers() must always be called in pairs,
1303 // cannot nest with above clear()/update_pointers().
1304 COMPILER2_PRESENT(DerivedPointerTable::clear());
1305 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahCollectorPolicy::init_evac);
1306 ShenandoahFixRootsTask update_roots_task(&rp);
1307 workers()->run_task(&update_roots_task);
1308 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1309 }
1310
1311 #ifdef ASSERT
1312 {
1313 AssertToSpaceClosure cl;
1314 CodeBlobToOopClosure code_cl(&cl, !CodeBlobToOopClosure::FixRelocations);
1315 ShenandoahRootEvacuator rp(this, 1);
1316 rp.process_evacuate_roots(&cl, &code_cl, 0);
1317 }
1318 #endif
1319 }
1320
1321
1322 void ShenandoahHeap::do_evacuation() {
1323
1324 parallel_evacuate();
1325
1326 if (ShenandoahVerify && ! cancelled_concgc()) {
1327 VM_ShenandoahVerifyHeapAfterEvacuation verify_after_evacuation;
1328 if (Thread::current()->is_VM_thread()) {
1329 verify_after_evacuation.doit();
1330 } else {
1331 VMThread::execute(&verify_after_evacuation);
1332 }
1333 }
1334
1335 }
1336
1337 void ShenandoahHeap::parallel_evacuate() {
1338 log_develop_trace(gc)("starting parallel_evacuate");
1339
1340 _shenandoah_policy->record_phase_start(ShenandoahCollectorPolicy::conc_evac);
1341
1342 if (log_is_enabled(Trace, gc, region)) {
1343 ResourceMark rm;
1344 outputStream *out = Log(gc, region)::trace_stream();
1345 out->print("Printing all available regions");
1346 print_heap_regions(out);
1347 }
1348
1349 if (log_is_enabled(Trace, gc, cset)) {
1350 ResourceMark rm;
1351 outputStream *out = Log(gc, cset)::trace_stream();
1352 out->print("Printing collection set which contains "SIZE_FORMAT" regions:\n", _collection_set->count());
1353 _collection_set->print(out);
1354
1355 out->print("Printing free set which contains "SIZE_FORMAT" regions:\n", _free_regions->count());
1356 _free_regions->print(out);
1357 }
1358
1359 ParallelEvacuationTask evacuationTask = ParallelEvacuationTask(this, _collection_set);
1360
1361
1362 workers()->run_task(&evacuationTask);
1363
1364 if (log_is_enabled(Trace, gc, cset)) {
1365 ResourceMark rm;
1366 outputStream *out = Log(gc, cset)::trace_stream();
1367 out->print("Printing postgc collection set which contains "SIZE_FORMAT" regions:\n",
1368 _collection_set->count());
1369
1370 _collection_set->print(out);
1371
1372 out->print("Printing postgc free regions which contain "SIZE_FORMAT" free regions:\n",
1373 _free_regions->count());
1374 _free_regions->print(out);
1375
1376 }
1377
1378 if (log_is_enabled(Trace, gc, region)) {
1379 ResourceMark rm;
1380 outputStream *out = Log(gc, region)::trace_stream();
1381 out->print_cr("all regions after evacuation:");
1382 print_heap_regions(out);
1383 }
1384
1385 _shenandoah_policy->record_phase_end(ShenandoahCollectorPolicy::conc_evac);
1386 }
1387
1388 class VerifyEvacuationClosure: public ExtendedOopClosure {
1389 private:
1390 ShenandoahHeap* _heap;
1391 ShenandoahHeapRegion* _from_region;
1392
1393 public:
1394 VerifyEvacuationClosure(ShenandoahHeapRegion* from_region) :
1395 _heap(ShenandoahHeap::heap()), _from_region(from_region) { }
1396 private:
1397 template <class T>
1398 inline void do_oop_work(T* p) {
1399 oop heap_oop = oopDesc::load_decode_heap_oop(p);
1400 if (! oopDesc::is_null(heap_oop)) {
1401 guarantee(! _from_region->is_in(heap_oop), "no references to from-region allowed after evacuation: "PTR_FORMAT, p2i((HeapWord*) heap_oop));
1402 }
1403 }
1404
1405 public:
1406 void do_oop(oop* p) {
1407 do_oop_work(p);
1408 }
1409
1410 void do_oop(narrowOop* p) {
1411 do_oop_work(p);
1412 }
1413
1414 };
1415
1416 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1417
1418 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1419
1420 CodeBlobToOopClosure blobsCl(cl, false);
1421 CLDToOopClosure cldCl(cl);
1422
1423 ShenandoahRootProcessor rp(this, 1);
1424 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, 0);
1425 }
1426
1427 void ShenandoahHeap::verify_evacuation(ShenandoahHeapRegion* from_region) {
1428
1429 VerifyEvacuationClosure rootsCl(from_region);
1430 roots_iterate(&rootsCl);
1431
1432 }
1433
1434 bool ShenandoahHeap::supports_tlab_allocation() const {
1435 return true;
1436 }
1437
1438
1439 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1440 size_t idx = _free_regions->current_index();
1441 ShenandoahHeapRegion* current = _free_regions->get(idx);
1442 if (current == NULL) {
1443 return 0;
1444 } else if (current->free() > MinTLABSize) {
1445 // Current region has enough space left, can use it.
1446 return current->free();
1447 } else {
1448 // No more space in current region, we will take next free region
1449 // on the next TLAB allocation.
1450 return ShenandoahHeapRegion::region_size_bytes();
1451 }
1452 }
1453
1454 size_t ShenandoahHeap::max_tlab_size() const {
1455 return ShenandoahHeapRegion::region_size_bytes();
1456 }
1457
1458 class ResizeGCLABClosure : public ThreadClosure {
1459 public:
1460 void do_thread(Thread* thread) {
1461 thread->gclab().resize();
1462 }
1463 };
1464
1465 void ShenandoahHeap::resize_all_tlabs() {
1466 CollectedHeap::resize_all_tlabs();
1467
1468 ResizeGCLABClosure cl;
1469 Threads::threads_do(&cl);
1470 }
1471
1472 class AccumulateStatisticsGCLABClosure : public ThreadClosure {
1473 public:
1474 void do_thread(Thread* thread) {
1475 thread->gclab().accumulate_statistics();
1476 thread->gclab().initialize_statistics();
1477 }
1478 };
1479
1480 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1481 AccumulateStatisticsGCLABClosure cl;
1482 Threads::threads_do(&cl);
1483 }
1484
1485 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1486 return true;
1487 }
1488
1489 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1490 // Overridden to do nothing.
1491 return new_obj;
1492 }
1493
1494 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1495 return true;
1496 }
1497
1498 bool ShenandoahHeap::card_mark_must_follow_store() const {
1499 return false;
1500 }
1501
1502 void ShenandoahHeap::collect(GCCause::Cause cause) {
1503 assert(cause != GCCause::_gc_locker, "no JNI critical callback");
1504 if (GCCause::is_user_requested_gc(cause)) {
1505 if (! DisableExplicitGC) {
1506 _concurrent_gc_thread->do_full_gc(cause);
1507 }
1508 } else if (cause == GCCause::_allocation_failure) {
1509 collector_policy()->set_should_clear_all_soft_refs(true);
1510 _concurrent_gc_thread->do_full_gc(cause);
1511 }
1512 }
1513
1514 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1515 //assert(false, "Shouldn't need to do full collections");
1516 }
1517
1518 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1519 Unimplemented();
1520 return NULL;
1521
1522 }
1523
1524 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1525 return _shenandoah_policy;
1526 }
1527
1528
1529 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1530 Space* sp = heap_region_containing(addr);
1531 if (sp != NULL) {
1532 return sp->block_start(addr);
1533 }
1534 return NULL;
1535 }
1536
1537 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1538 Space* sp = heap_region_containing(addr);
1539 assert(sp != NULL, "block_size of address outside of heap");
1540 return sp->block_size(addr);
1541 }
1542
1543 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1544 Space* sp = heap_region_containing(addr);
1545 return sp->block_is_obj(addr);
1546 }
1547
1548 jlong ShenandoahHeap::millis_since_last_gc() {
1549 return 0;
1550 }
1551
1552 void ShenandoahHeap::prepare_for_verify() {
1553 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1554 ensure_parsability(false);
1555 }
1556 }
1557
1558 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1559 workers()->print_worker_threads_on(st);
1560 }
1561
1562 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1563 workers()->threads_do(tcl);
1564 }
1565
1566 void ShenandoahHeap::print_tracing_info() const {
1567 if (log_is_enabled(Info, gc, stats)) {
1568 ResourceMark rm;
1569 outputStream* out = Log(gc, stats)::info_stream();
1570 _shenandoah_policy->print_tracing_info(out);
1571 }
1572 }
1573
1574 class ShenandoahVerifyRootsClosure: public ExtendedOopClosure {
1575 private:
1576 ShenandoahHeap* _heap;
1577 VerifyOption _vo;
1578 bool _failures;
1579 public:
1580 // _vo == UsePrevMarking -> use "prev" marking information,
1581 // _vo == UseNextMarking -> use "next" marking information,
1582 // _vo == UseMarkWord -> use mark word from object header.
1583 ShenandoahVerifyRootsClosure(VerifyOption vo) :
1584 _heap(ShenandoahHeap::heap()),
1585 _vo(vo),
1586 _failures(false) { }
1587
1588 bool failures() { return _failures; }
1589
1590 private:
1591 template <class T>
1592 inline void do_oop_work(T* p) {
1593 oop obj = oopDesc::load_decode_heap_oop(p);
1594 if (! oopDesc::is_null(obj) && ! obj->is_oop()) {
1595 { // Just for debugging.
1596 tty->print_cr("Root location "PTR_FORMAT
1597 "verified "PTR_FORMAT, p2i(p), p2i((void*) obj));
1598 // obj->print_on(tty);
1599 }
1600 }
1601 guarantee(obj->is_oop_or_null(), "is oop or null");
1602 }
1603
1604 public:
1605 void do_oop(oop* p) {
1606 do_oop_work(p);
1607 }
1608
1609 void do_oop(narrowOop* p) {
1610 do_oop_work(p);
1611 }
1612
1613 };
1614
1615 class ShenandoahVerifyHeapClosure: public ObjectClosure {
1616 private:
1617 ShenandoahVerifyRootsClosure _rootsCl;
1618 public:
1619 ShenandoahVerifyHeapClosure(ShenandoahVerifyRootsClosure rc) :
1620 _rootsCl(rc) {};
1621
1622 void do_object(oop p) {
1623 _rootsCl.do_oop(&p);
1624 }
1625 };
1626
1627 void ShenandoahHeap::verify(VerifyOption vo) {
1628 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1629
1630 ShenandoahVerifyRootsClosure rootsCl(vo);
1631
1632 assert(Thread::current()->is_VM_thread(),
1633 "Expected to be executed serially by the VM thread at this point");
1634
1635 roots_iterate(&rootsCl);
1636
1637 bool failures = rootsCl.failures();
1638 log_trace(gc)("verify failures: %s", BOOL_TO_STR(failures));
1639
1640 ShenandoahVerifyHeapClosure heapCl(rootsCl);
1641
1642 object_iterate(&heapCl);
1643 // TODO: Implement rest of it.
1644 } else {
1645 tty->print("(SKIPPING roots, heapRegions, remset) ");
1646 }
1647 }
1648 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1649 return _free_regions->capacity();
1650 }
1651
1652 class ShenandoahIterateObjectClosureRegionClosure: public ShenandoahHeapRegionClosure {
1653 ObjectClosure* _cl;
1654 public:
1655 ShenandoahIterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
1656 bool doHeapRegion(ShenandoahHeapRegion* r) {
1657 ShenandoahHeap::heap()->marked_object_iterate(r, _cl);
1658 return false;
1659 }
1660 };
1661
1662 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1663 ShenandoahIterateObjectClosureRegionClosure blk(cl);
1664 heap_region_iterate(&blk, false, true);
1665 }
1666
1667 class ShenandoahSafeObjectIterateAdjustPtrsClosure : public MetadataAwareOopClosure {
1668 private:
1669 ShenandoahHeap* _heap;
1670
1671 public:
1672 ShenandoahSafeObjectIterateAdjustPtrsClosure() : _heap(ShenandoahHeap::heap()) {}
1673
1674 private:
1675 template <class T>
1676 inline void do_oop_work(T* p) {
1677 T o = oopDesc::load_heap_oop(p);
1678 if (!oopDesc::is_null(o)) {
1679 oop obj = oopDesc::decode_heap_oop_not_null(o);
1680 oopDesc::encode_store_heap_oop(p, BrooksPointer::forwardee(obj));
1681 }
1682 }
1683 public:
1684 void do_oop(oop* p) {
1685 do_oop_work(p);
1686 }
1687 void do_oop(narrowOop* p) {
1688 do_oop_work(p);
1689 }
1690 };
1691
1692 class ShenandoahSafeObjectIterateAndUpdate : public ObjectClosure {
1693 private:
1694 ObjectClosure* _cl;
1695 public:
1696 ShenandoahSafeObjectIterateAndUpdate(ObjectClosure *cl) : _cl(cl) {}
1697
1698 virtual void do_object(oop obj) {
1699 assert (oopDesc::unsafe_equals(obj, BrooksPointer::forwardee(obj)),
1700 "avoid double-counting: only non-forwarded objects here");
1701
1702 // Fix up the ptrs.
1703 ShenandoahSafeObjectIterateAdjustPtrsClosure adjust_ptrs;
1704 obj->oop_iterate(&adjust_ptrs);
1705
1706 // Can reply the object now:
1707 _cl->do_object(obj);
1708 }
1709 };
1710
1711 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1712 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1713
1714 // Safe iteration does objects only with correct references.
1715 // This is why we skip dirty regions that have stale copies of objects,
1716 // and fix up the pointers in the returned objects.
1717
1718 ShenandoahSafeObjectIterateAndUpdate safe_cl(cl);
1719 ShenandoahIterateObjectClosureRegionClosure blk(&safe_cl);
1720 heap_region_iterate(&blk,
1721 /* skip_dirty_regions = */ true,
1722 /* skip_humongous_continuations = */ true);
1723
1724 _need_update_refs = false; // already updated the references
1725 }
1726
1727 // Apply blk->doHeapRegion() on all committed regions in address order,
1728 // terminating the iteration early if doHeapRegion() returns true.
1729 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_dirty_regions, bool skip_humongous_continuation) const {
1730 for (size_t i = 0; i < _num_regions; i++) {
1731 ShenandoahHeapRegion* current = _ordered_regions->get(i);
1732 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1733 continue;
1734 }
1735 if (skip_dirty_regions && in_collection_set(current)) {
1736 continue;
1737 }
1738 if (blk->doHeapRegion(current)) {
1739 return;
1740 }
1741 }
1742 }
1743
1744 class ClearLivenessClosure : public ShenandoahHeapRegionClosure {
1745 ShenandoahHeap* sh;
1746 public:
1747 ClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) { }
1748
1749 bool doHeapRegion(ShenandoahHeapRegion* r) {
1750 r->clear_live_data();
1751 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1752 return false;
1753 }
1754 };
1755
1756 void ShenandoahHeap::start_concurrent_marking() {
1757
1758 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::accumulate_stats);
1759 accumulate_statistics_all_tlabs();
1760 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::accumulate_stats);
1761
1762 set_concurrent_mark_in_progress(true);
1763 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1764 if (UseTLAB) {
1765 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::make_parsable);
1766 ensure_parsability(true);
1767 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::make_parsable);
1768 }
1769
1770 _shenandoah_policy->record_bytes_allocated(_bytes_allocated_since_cm);
1771 _used_start_gc = used();
1772
1773 #ifdef ASSERT
1774 if (ShenandoahDumpHeapBeforeConcurrentMark) {
1775 ensure_parsability(false);
1776 print_all_refs("pre-mark");
1777 }
1778 #endif
1779
1780 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::clear_liveness);
1781 ClearLivenessClosure clc(this);
1782 heap_region_iterate(&clc);
1783 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::clear_liveness);
1784
1785 if (UseShenandoahMatrix) {
1786 connection_matrix()->clear_all();
1787 }
1788 // print_all_refs("pre -mark");
1789
1790 // oopDesc::_debug = true;
1791
1792 // Make above changes visible to worker threads
1793 OrderAccess::fence();
1794
1795 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::scan_roots);
1796 concurrentMark()->init_mark_roots();
1797 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::scan_roots);
1798
1799 // print_all_refs("pre-mark2");
1800 }
1801
1802 class VerifyAfterEvacuationClosure : public ExtendedOopClosure {
1803
1804 ShenandoahHeap* _sh;
1805
1806 public:
1807 VerifyAfterEvacuationClosure() : _sh ( ShenandoahHeap::heap() ) {}
1808
1809 template<class T> void do_oop_nv(T* p) {
1810 T heap_oop = oopDesc::load_heap_oop(p);
1811 if (!oopDesc::is_null(heap_oop)) {
1812 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1813 guarantee(_sh->in_collection_set(obj) == (! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))),
1814 "forwarded objects can only exist in dirty (from-space) regions is_dirty: %s, is_forwarded: %s obj-klass: %s, marked: %s",
1815 BOOL_TO_STR(_sh->in_collection_set(obj)),
1816 BOOL_TO_STR(! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))),
1817 obj->klass()->external_name(),
1818 BOOL_TO_STR(_sh->is_marked_complete(obj))
1819 );
1820 obj = oopDesc::bs()->read_barrier(obj);
1821 guarantee(! _sh->in_collection_set(obj), "forwarded oops must not point to dirty regions");
1822 guarantee(obj->is_oop(), "is_oop");
1823 guarantee(Metaspace::contains(obj->klass()), "klass pointer must go to metaspace");
1824 }
1825 }
1826
1827 void do_oop(oop* p) { do_oop_nv(p); }
1828 void do_oop(narrowOop* p) { do_oop_nv(p); }
1829
1830 };
1831
1832 void ShenandoahHeap::verify_heap_after_evacuation() {
1833
1834 verify_heap_size_consistency();
1835
1836 ensure_parsability(false);
1837
1838 VerifyAfterEvacuationClosure cl;
1839 roots_iterate(&cl);
1840
1841 ObjectToOopClosure objs(&cl);
1842 object_iterate(&objs);
1843
1844 }
1845
1846 void ShenandoahHeap::swap_mark_bitmaps() {
1847 // Swap bitmaps.
1848 CMBitMap* tmp1 = _complete_mark_bit_map;
1849 _complete_mark_bit_map = _next_mark_bit_map;
1850 _next_mark_bit_map = tmp1;
1851
1852 // Swap top-at-mark-start pointers
1853 HeapWord** tmp2 = _complete_top_at_mark_starts;
1854 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1855 _next_top_at_mark_starts = tmp2;
1856
1857 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1858 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1859 _next_top_at_mark_starts_base = tmp3;
1860 }
1861
1862 class VerifyReachableHeapClosure : public ExtendedOopClosure {
1863 private:
1864 SCMObjToScanQueue* _queue;
1865 ShenandoahHeap* _heap;
1866 CMBitMap* _map;
1867 bool _check_matrix;
1868 oop _obj;
1869 public:
1870 VerifyReachableHeapClosure(SCMObjToScanQueue* queue, CMBitMap* map, bool check_matrix) :
1871 _queue(queue), _heap(ShenandoahHeap::heap()), _map(map), _check_matrix(check_matrix) {};
1872 template <class T>
1873 void do_oop_work(T* p) {
1874 T o = oopDesc::load_heap_oop(p);
1875 if (!oopDesc::is_null(o)) {
1876 oop obj = oopDesc::decode_heap_oop_not_null(o);
1877 guarantee(check_obj_alignment(obj), "sanity");
1878
1879 guarantee(!oopDesc::is_null(obj), "sanity");
1880 guarantee(_heap->is_in(obj), "sanity");
1881
1882 oop forw = BrooksPointer::forwardee(obj);
1883 guarantee(!oopDesc::is_null(forw), "sanity");
1884 guarantee(_heap->is_in(forw), "sanity");
1885
1886 guarantee(oopDesc::unsafe_equals(obj, forw), "should not be forwarded");
1887
1888 if (_check_matrix) {
1889 size_t from_idx = _heap->heap_region_index_containing(p);
1890 size_t to_idx = _heap->heap_region_index_containing(obj);
1891 if (!_heap->connection_matrix()->is_connected(from_idx, to_idx)) {
1892 tty->print_cr("from-obj: ");
1893 _obj->print_on(tty);
1894 tty->print_cr("to-obj:");
1895 obj->print_on(tty);
1896 tty->print_cr("from-obj allocated after mark: %s", BOOL_TO_STR(_heap->allocated_after_complete_mark_start((HeapWord*) _obj)));
1897 tty->print_cr("to-obj allocated after mark: %s", BOOL_TO_STR(_heap->allocated_after_complete_mark_start((HeapWord*) obj)));
1898 tty->print_cr("from-obj marked: %s", BOOL_TO_STR(_heap->is_marked_complete(_obj)));
1899 tty->print_cr("to-obj marked: %s", BOOL_TO_STR(_heap->is_marked_complete(obj)));
1900 tty->print_cr("from-idx: " SIZE_FORMAT ", to-idx: " SIZE_FORMAT, from_idx, to_idx);
1901
1902 oop fwd_from = BrooksPointer::forwardee(_obj);
1903 oop fwd_to = BrooksPointer::forwardee(obj);
1904 tty->print_cr("from-obj forwardee: " PTR_FORMAT, p2i(fwd_from));
1905 tty->print_cr("to-obj forwardee: " PTR_FORMAT, p2i(fwd_to));
1906 tty->print_cr("forward(from-obj) marked: %s", BOOL_TO_STR(_heap->is_marked_complete(fwd_from)));
1907 tty->print_cr("forward(to-obj) marked: %s", BOOL_TO_STR(_heap->is_marked_complete(fwd_to)));
1908 size_t fwd_from_idx = _heap->heap_region_index_containing(fwd_from);
1909 size_t fwd_to_idx = _heap->heap_region_index_containing(fwd_to);
1910 tty->print_cr("forward(from-idx): " SIZE_FORMAT ", forward(to-idx): " SIZE_FORMAT, fwd_from_idx, fwd_to_idx);
1911 tty->print_cr("forward(from) connected with forward(to)? %s", BOOL_TO_STR(_heap->connection_matrix()->is_connected(fwd_from_idx, fwd_to_idx)));
1912 }
1913 guarantee(oopDesc::unsafe_equals(ShenandoahBarrierSet::resolve_oop_static_not_null(obj), obj), "polizeilich verboten");
1914 guarantee(_heap->connection_matrix()->is_connected(from_idx, to_idx), "must be connected");
1915 }
1916
1917 if (_map->parMark((HeapWord*) obj)) {
1918 _queue->push(SCMTask(obj));
1919 }
1920 }
1921 }
1922
1923 void do_oop(oop* p) { do_oop_work(p); }
1924 void do_oop(narrowOop* p) { do_oop_work(p); }
1925 void set_obj(oop o) { _obj = o; }
1926 };
1927
1928 void ShenandoahHeap::verify_heap_reachable_at_safepoint() {
1929 guarantee(SafepointSynchronize::is_at_safepoint(), "only when nothing else happens");
1930 guarantee(ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix),
1931 "only when these are enabled, and bitmap is initialized in ShenandoahHeap::initialize");
1932
1933 OrderAccess::fence();
1934 ensure_parsability(false);
1935
1936 // Allocate temporary bitmap for storing marking wavefront:
1937 MemRegion mr = MemRegion(_verification_bit_map.startWord(), _verification_bit_map.endWord());
1938 _verification_bit_map.clear_range_large(mr);
1939
1940 // Initialize a single queue
1941 SCMObjToScanQueue* q = new SCMObjToScanQueue();
1942 q->initialize();
1943
1944 // Scan root set
1945 ShenandoahRootProcessor rp(this, 1);
1946
1947 {
1948 VerifyReachableHeapClosure cl(q, &_verification_bit_map, false);
1949 CLDToOopClosure cld_cl(&cl);
1950 CodeBlobToOopClosure code_cl(&cl, ! CodeBlobToOopClosure::FixRelocations);
1951 rp.process_all_roots(&cl, &cl, &cld_cl, &code_cl, 0);
1952 }
1953
1954 // Finish the scan
1955 {
1956 VerifyReachableHeapClosure cl(q, &_verification_bit_map, UseShenandoahMatrix && VerifyShenandoahMatrix);
1957 SCMTask task;
1958 while ((q->pop_buffer(task) ||
1959 q->pop_local(task) ||
1960 q->pop_overflow(task))) {
1961 oop obj = task.obj();
1962 assert(!oopDesc::is_null(obj), "must not be null");
1963 cl.set_obj(obj);
1964 obj->oop_iterate(&cl);
1965 }
1966 }
1967
1968 // Clean up!
1969 delete(q);
1970 }
1971
1972 void ShenandoahHeap::stop_concurrent_marking() {
1973 assert(concurrent_mark_in_progress(), "How else could we get here?");
1974 if (! cancelled_concgc()) {
1975 // If we needed to update refs, and concurrent marking has been cancelled,
1976 // we need to finish updating references.
1977 set_need_update_refs(false);
1978 swap_mark_bitmaps();
1979 }
1980 set_concurrent_mark_in_progress(false);
1981
1982 if (log_is_enabled(Trace, gc, region)) {
1983 ResourceMark rm;
1984 outputStream* out = Log(gc, region)::trace_stream();
1985 print_heap_regions(out);
1986 }
1987
1988 }
1989
1990 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1991 _concurrent_mark_in_progress = in_progress ? 1 : 0;
1992 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1993 }
1994
1995 void ShenandoahHeap::set_evacuation_in_progress_concurrently(bool in_progress) {
1996 // Note: it is important to first release the _evacuation_in_progress flag here,
1997 // so that Java threads can get out of oom_during_evacuation() and reach a safepoint,
1998 // in case a VM task is pending.
1999 set_evacuation_in_progress(in_progress);
2000 MutexLocker mu(Threads_lock);
2001 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
2002 }
2003
2004 void ShenandoahHeap::set_evacuation_in_progress_at_safepoint(bool in_progress) {
2005 assert(SafepointSynchronize::is_at_safepoint(), "Only call this at safepoint");
2006 set_evacuation_in_progress(in_progress);
2007 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
2008 }
2009
2010 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2011 _evacuation_in_progress = in_progress ? 1 : 0;
2012 OrderAccess::fence();
2013 }
2014
2015 void ShenandoahHeap::verify_copy(oop p,oop c){
2016 assert(! oopDesc::unsafe_equals(p, oopDesc::bs()->read_barrier(p)), "forwarded correctly");
2017 assert(oopDesc::unsafe_equals(oopDesc::bs()->read_barrier(p), c), "verify pointer is correct");
2018 if (p->klass() != c->klass()) {
2019 print_heap_regions();
2020 }
2021 assert(p->klass() == c->klass(), "verify class p-size: "INT32_FORMAT" c-size: "INT32_FORMAT, p->size(), c->size());
2022 assert(p->size() == c->size(), "verify size");
2023 // Object may have been locked between copy and verification
2024 // assert(p->mark() == c->mark(), "verify mark");
2025 assert(oopDesc::unsafe_equals(c, oopDesc::bs()->read_barrier(c)), "verify only forwarded once");
2026 }
2027
2028 void ShenandoahHeap::oom_during_evacuation() {
2029 log_develop_trace(gc)("Out of memory during evacuation, cancel evacuation, schedule full GC by thread %d",
2030 Thread::current()->osthread()->thread_id());
2031
2032 // We ran out of memory during evacuation. Cancel evacuation, and schedule a full-GC.
2033 collector_policy()->set_should_clear_all_soft_refs(true);
2034 concurrent_thread()->try_set_full_gc();
2035 cancel_concgc(_oom_evacuation);
2036
2037 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
2038 assert(! Threads_lock->owned_by_self()
2039 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here");
2040 log_warning(gc)("OOM during evacuation. Let Java thread wait until evacuation finishes.");
2041 while (_evacuation_in_progress) { // wait.
2042 Thread::current()->_ParkEvent->park(1);
2043 }
2044 }
2045
2046 }
2047
2048 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
2049 // Initialize Brooks pointer for the next object
2050 HeapWord* result = obj + BrooksPointer::word_size();
2051 BrooksPointer::initialize(oop(result));
2052 return result;
2053 }
2054
2055 uint ShenandoahHeap::oop_extra_words() {
2056 return BrooksPointer::word_size();
2057 }
2058
2059 void ShenandoahHeap::grow_heap_by(size_t num_regions) {
2060 size_t old_num_regions = _num_regions;
2061 ensure_new_regions(num_regions);
2062 for (size_t i = 0; i < num_regions; i++) {
2063 size_t new_region_index = i + old_num_regions;
2064 HeapWord* start = ((HeapWord*) base()) + (ShenandoahHeapRegion::region_size_bytes() / HeapWordSize) * new_region_index;
2065 ShenandoahHeapRegion* new_region = new ShenandoahHeapRegion(this, start, ShenandoahHeapRegion::region_size_bytes() / HeapWordSize, new_region_index);
2066
2067 if (log_is_enabled(Trace, gc, region)) {
2068 ResourceMark rm;
2069 outputStream* out = Log(gc, region)::trace_stream();
2070 out->print_cr("allocating new region at index: "SIZE_FORMAT, new_region_index);
2071 new_region->print_on(out);
2072 }
2073
2074 assert(_ordered_regions->active_regions() == new_region->region_number(), "must match");
2075 _ordered_regions->add_region(new_region);
2076 _in_cset_fast_test_base[new_region_index] = false; // Not in cset
2077 _next_top_at_mark_starts_base[new_region_index] = new_region->bottom();
2078 _complete_top_at_mark_starts_base[new_region_index] = new_region->bottom();
2079
2080 _free_regions->add_region(new_region);
2081 }
2082 }
2083
2084 void ShenandoahHeap::ensure_new_regions(size_t new_regions) {
2085
2086 size_t num_regions = _num_regions;
2087 size_t new_num_regions = num_regions + new_regions;
2088 assert(new_num_regions <= _max_regions, "we checked this earlier");
2089
2090 size_t expand_size = new_regions * ShenandoahHeapRegion::region_size_bytes();
2091 log_trace(gc, region)("expanding storage by "SIZE_FORMAT_HEX" bytes, for "SIZE_FORMAT" new regions", expand_size, new_regions);
2092 bool success = _storage.expand_by(expand_size, ShenandoahAlwaysPreTouch);
2093 assert(success, "should always be able to expand by requested size");
2094
2095 _num_regions = new_num_regions;
2096
2097 }
2098
2099 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
2100 _heap(ShenandoahHeap::heap_no_check()) {
2101 }
2102
2103 void ShenandoahForwardedIsAliveClosure::init(ShenandoahHeap* heap) {
2104 _heap = heap;
2105 }
2106
2107 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
2108
2109 assert(_heap != NULL, "sanity");
2110 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
2111 #ifdef ASSERT
2112 if (_heap->concurrent_mark_in_progress()) {
2113 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
2114 }
2115 #endif
2116 assert(!oopDesc::is_null(obj), "null");
2117 return _heap->is_marked_next(obj);
2118 }
2119
2120 void ShenandoahHeap::ref_processing_init() {
2121 MemRegion mr = reserved_region();
2122
2123 isAlive.init(ShenandoahHeap::heap());
2124 assert(_max_workers > 0, "Sanity");
2125
2126 _ref_processor =
2127 new ReferenceProcessor(mr, // span
2128 ParallelRefProcEnabled,
2129 // mt processing
2130 _max_workers,
2131 // degree of mt processing
2132 true,
2133 // mt discovery
2134 _max_workers,
2135 // degree of mt discovery
2136 false,
2137 // Reference discovery is not atomic
2138 &isAlive);
2139 }
2140
2141 size_t ShenandoahHeap::num_regions() {
2142 return _num_regions;
2143 }
2144
2145 size_t ShenandoahHeap::max_regions() {
2146 return _max_regions;
2147 }
2148
2149 GCTracer* ShenandoahHeap::tracer() {
2150 return shenandoahPolicy()->tracer();
2151 }
2152
2153 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2154 return _free_regions->used();
2155 }
2156
2157 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
2158 if (try_cancel_concgc()) {
2159 log_info(gc)("Cancelling concurrent GC: %s", GCCause::to_string(cause));
2160 _shenandoah_policy->report_concgc_cancelled();
2161 }
2162 }
2163
2164 void ShenandoahHeap::cancel_concgc(ShenandoahCancelCause cause) {
2165 if (try_cancel_concgc()) {
2166 log_info(gc)("Cancelling concurrent GC: %s", cancel_cause_to_string(cause));
2167 _shenandoah_policy->report_concgc_cancelled();
2168 }
2169 }
2170
2171 const char* ShenandoahHeap::cancel_cause_to_string(ShenandoahCancelCause cause) {
2172 switch (cause) {
2173 case _oom_evacuation:
2174 return "Out of memory for evacuation";
2175 case _vm_stop:
2176 return "Stopping VM";
2177 default:
2178 return "Unknown";
2179 }
2180 }
2181
2182 uint ShenandoahHeap::max_workers() {
2183 return _max_workers;
2184 }
2185
2186 void ShenandoahHeap::stop() {
2187 // The shutdown sequence should be able to terminate when GC is running.
2188
2189 // Step 1. Notify control thread that we are in shutdown.
2190 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2191 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2192 _concurrent_gc_thread->prepare_for_graceful_shutdown();
2193
2194 // Step 2. Notify GC workers that we are cancelling GC.
2195 cancel_concgc(_vm_stop);
2196
2197 // Step 3. Wait until GC worker exits normally.
2198 _concurrent_gc_thread->stop();
2199 }
2200
2201 void ShenandoahHeap::unload_classes_and_cleanup_tables() {
2202 ShenandoahForwardedIsAliveClosure is_alive;
2203 // Unload classes and purge SystemDictionary.
2204 bool purged_class = SystemDictionary::do_unloading(&is_alive, true);
2205 ParallelCleaningTask unlink_task(&is_alive, true, true, _workers->active_workers(), purged_class);
2206 _workers->run_task(&unlink_task);
2207 ClassLoaderDataGraph::purge();
2208 }
2209
2210 void ShenandoahHeap::set_need_update_refs(bool need_update_refs) {
2211 _need_update_refs = need_update_refs;
2212 }
2213
2214 //fixme this should be in heapregionset
2215 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2216 size_t region_idx = r->region_number() + 1;
2217 ShenandoahHeapRegion* next = _ordered_regions->get(region_idx);
2218 guarantee(next->region_number() == region_idx, "region number must match");
2219 while (next->is_humongous()) {
2220 region_idx = next->region_number() + 1;
2221 next = _ordered_regions->get(region_idx);
2222 guarantee(next->region_number() == region_idx, "region number must match");
2223 }
2224 return next;
2225 }
2226
2227 void ShenandoahHeap::set_region_in_collection_set(size_t region_index, bool b) {
2228 _in_cset_fast_test_base[region_index] = b;
2229 }
2230
2231 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2232 return _monitoring_support;
2233 }
2234
2235 CMBitMap* ShenandoahHeap::complete_mark_bit_map() {
2236 return _complete_mark_bit_map;
2237 }
2238
2239 CMBitMap* ShenandoahHeap::next_mark_bit_map() {
2240 return _next_mark_bit_map;
2241 }
2242
2243 void ShenandoahHeap::add_free_region(ShenandoahHeapRegion* r) {
2244 _free_regions->add_region(r);
2245 }
2246
2247 void ShenandoahHeap::clear_free_regions() {
2248 _free_regions->clear();
2249 }
2250
2251 address ShenandoahHeap::in_cset_fast_test_addr() {
2252 return (address) (ShenandoahHeap::heap()->_in_cset_fast_test);
2253 }
2254
2255 address ShenandoahHeap::cancelled_concgc_addr() {
2256 return (address) &(ShenandoahHeap::heap()->_cancelled_concgc);
2257 }
2258
2259 void ShenandoahHeap::clear_cset_fast_test() {
2260 assert(_in_cset_fast_test_base != NULL, "sanity");
2261 memset(_in_cset_fast_test_base, false,
2262 _in_cset_fast_test_length * sizeof(bool));
2263 }
2264
2265 size_t ShenandoahHeap::conservative_max_heap_alignment() {
2266 return ShenandoahMaxRegionSize;
2267 }
2268
2269 size_t ShenandoahHeap::bytes_allocated_since_cm() {
2270 return _bytes_allocated_since_cm;
2271 }
2272
2273 void ShenandoahHeap::set_bytes_allocated_since_cm(size_t bytes) {
2274 _bytes_allocated_since_cm = bytes;
2275 }
2276
2277 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2278 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2279 _next_top_at_mark_starts[index] = addr;
2280 }
2281
2282 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2283 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2284 return _next_top_at_mark_starts[index];
2285 }
2286
2287 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2288 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2289 _complete_top_at_mark_starts[index] = addr;
2290 }
2291
2292 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2293 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2294 return _complete_top_at_mark_starts[index];
2295 }
2296
2297 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2298 _full_gc_in_progress = in_progress;
2299 }
2300
2301 bool ShenandoahHeap::is_full_gc_in_progress() const {
2302 return _full_gc_in_progress;
2303 }
2304
2305 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2306 _update_refs_in_progress = in_progress;
2307 }
2308
2309 bool ShenandoahHeap::is_update_refs_in_progress() const {
2310 return _update_refs_in_progress;
2311 }
2312
2313 class NMethodOopInitializer : public OopClosure {
2314 private:
2315 ShenandoahHeap* _heap;
2316 public:
2317 NMethodOopInitializer() : _heap(ShenandoahHeap::heap()) {
2318 }
2319
2320 private:
2321 template <class T>
2322 inline void do_oop_work(T* p) {
2323 T o = oopDesc::load_heap_oop(p);
2324 if (! oopDesc::is_null(o)) {
2325 oop obj1 = oopDesc::decode_heap_oop_not_null(o);
2326 oop obj2 = oopDesc::bs()->write_barrier(obj1);
2327 if (! oopDesc::unsafe_equals(obj1, obj2)) {
2328 oopDesc::encode_store_heap_oop(p, obj2);
2329 }
2330 }
2331 }
2332
2333 public:
2334 void do_oop(oop* o) {
2335 do_oop_work(o);
2336 }
2337 void do_oop(narrowOop* o) {
2338 do_oop_work(o);
2339 }
2340 };
2341
2342 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2343 NMethodOopInitializer init;
2344 nm->oops_do(&init);
2345 nm->fix_oop_relocations();
2346 }
2347
2348 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2349 }
2350
2351 void ShenandoahHeap::pin_object(oop o) {
2352 heap_region_containing(o)->pin();
2353 }
2354
2355 void ShenandoahHeap::unpin_object(oop o) {
2356 heap_region_containing(o)->unpin();
2357 }
2358
2359
2360 GCTimer* ShenandoahHeap::gc_timer() const {
2361 return _gc_timer;
2362 }
2363
2364 class ShenandoahCountGarbageClosure : public ShenandoahHeapRegionClosure {
2365 private:
2366 size_t _garbage;
2367 public:
2368 ShenandoahCountGarbageClosure() : _garbage(0) {
2369 }
2370
2371 bool doHeapRegion(ShenandoahHeapRegion* r) {
2372 if (! r->is_humongous() && ! r->is_pinned() && ! r->in_collection_set()) {
2373 _garbage += r->garbage();
2374 }
2375 return false;
2376 }
2377
2378 size_t garbage() {
2379 return _garbage;
2380 }
2381 };
2382
2383 size_t ShenandoahHeap::garbage() {
2384 ShenandoahCountGarbageClosure cl;
2385 heap_region_iterate(&cl);
2386 return cl.garbage();
2387 }
2388
2389 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() {
2390 return _connection_matrix;
2391 }
2392
2393 ShenandoahPartialGC* ShenandoahHeap::partial_gc() {
2394 return _partial_gc;
2395 }
2396
2397 void ShenandoahHeap::do_partial_collection() {
2398 partial_gc()->do_partial_collection();
2399 }
2400
2401 template<class T>
2402 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2403 private:
2404 T cl;
2405 ShenandoahHeap* _heap;
2406 ShenandoahHeapRegionSet* _regions;
2407
2408 public:
2409 ShenandoahUpdateHeapRefsTask() :
2410 AbstractGangTask("Concurrent Update References Task"),
2411 cl(T()),
2412 _heap(ShenandoahHeap::heap()),
2413 _regions(ShenandoahHeap::heap()->regions()) {
2414 _regions->clear_current_index();
2415 }
2416
2417 void work(uint worker_id) {
2418 ShenandoahHeapRegion* r = _regions->claim_next();
2419 while (r != NULL && ! _heap->cancelled_concgc()) {
2420 if (! _heap->in_collection_set(r) &&
2421 ! r->is_empty()) {
2422 _heap->marked_object_oop_safe_iterate(r, &cl);
2423 } else if (_heap->in_collection_set(r)) {
2424 HeapWord* bottom = r->bottom();
2425 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2426 if (top > bottom) {
2427 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2428 }
2429 }
2430 r = _regions->claim_next();
2431 }
2432 }
2433 };
2434
2435 void ShenandoahHeap::concurrent_update_heap_references() {
2436 _shenandoah_policy->record_phase_start(ShenandoahCollectorPolicy::conc_update_refs);
2437 if (UseShenandoahMatrix) {
2438 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task;
2439 workers()->run_task(&task);
2440 } else {
2441 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task;
2442 workers()->run_task(&task);
2443 }
2444 _shenandoah_policy->record_phase_end(ShenandoahCollectorPolicy::conc_update_refs);
2445 }
2446
2447 void ShenandoahHeap::prepare_update_refs() {
2448 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2449 set_evacuation_in_progress_at_safepoint(false);
2450 set_update_refs_in_progress(true);
2451 ensure_parsability(true);
2452 connection_matrix()->clear_all();
2453 for (uint i = 0; i < _num_regions; i++) {
2454 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2455 r->set_concurrent_iteration_safe_limit(r->top());
2456 }
2457 }
2458
2459 void ShenandoahHeap::finish_update_refs() {
2460 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2461
2462 if (! cancelled_concgc()) {
2463 concurrentMark()->update_roots(ShenandoahCollectorPolicy::final_update_refs_roots);
2464 recycle_dirty_regions();
2465 set_need_update_refs(false);
2466
2467 if (ShenandoahVerify) {
2468 verify_update_refs();
2469 }
2470
2471 {
2472 // Rebuild the free set
2473 ShenandoahHeapLock hl(this);
2474 _free_regions->clear();
2475 size_t end = _ordered_regions->active_regions();
2476 for (size_t i = 0; i < end; i++) {
2477 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2478 if (!r->is_humongous()) {
2479 assert (!in_collection_set(r), "collection set should be clear");
2480 _free_regions->add_region(r);
2481 }
2482 }
2483 }
2484 }
2485 set_update_refs_in_progress(false);
2486 }
2487
2488 class ShenandoahVerifyUpdateRefsClosure : public ExtendedOopClosure {
2489 private:
2490 template <class T>
2491 void do_oop_work(T* p) {
2492 T o = oopDesc::load_heap_oop(p);
2493 if (! oopDesc::is_null(o)) {
2494 oop obj = oopDesc::decode_heap_oop_not_null(o);
2495 guarantee(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
2496 "must not be forwarded");
2497 }
2498 }
2499 public:
2500 void do_oop(oop* p) { do_oop_work(p); }
2501 void do_oop(narrowOop* p) { do_oop_work(p); }
2502 };
2503
2504 void ShenandoahHeap::verify_update_refs() {
2505
2506 ensure_parsability(false);
2507
2508 ShenandoahVerifyUpdateRefsClosure cl;
2509
2510 // Verify roots.
2511 {
2512 CodeBlobToOopClosure blobsCl(&cl, false);
2513 CLDToOopClosure cldCl(&cl);
2514 ShenandoahRootProcessor rp(this, 1);
2515 rp.process_all_roots(&cl, &cl, &cldCl, &blobsCl, 0);
2516 }
2517
2518 // Verify heap.
2519 for (uint i = 0; i < num_regions(); i++) {
2520 ShenandoahHeapRegion* r = regions()->get(i);
2521 marked_object_oop_iterate(r, &cl);
2522 }
2523 }
2524
2525 #ifdef ASSERT
2526 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2527 assert(_heap_lock == locked, "must be locked");
2528 assert(_heap_lock_owner == Thread::current(), "must be owned by current thread");
2529 }
2530
2531 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2532 Thread* thr = Thread::current();
2533 assert((_heap_lock == locked && _heap_lock_owner == thr) ||
2534 (SafepointSynchronize::is_at_safepoint() && thr->is_VM_thread()),
2535 "must own heap lock or by VM thread at safepoint");
2536 }
2537
2538 #endif