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 shenandoahPolicy()->record_peak_occupancy();
893 RecycleDirtyRegionsClosure cl;
894 cl.clear_bytes_reclaimed();
895
896 heap_region_iterate(&cl);
897
898 _shenandoah_policy->record_bytes_reclaimed(cl.bytes_reclaimed());
899 if (! cancelled_concgc()) {
900 clear_cset_fast_test();
901 }
902 }
903
904 ShenandoahFreeSet* ShenandoahHeap::free_regions() {
905 return _free_regions;
906 }
907
908 void ShenandoahHeap::print_heap_regions(outputStream* st) const {
909 _ordered_regions->print(st);
910 }
911
912 class PrintAllRefsOopClosure: public ExtendedOopClosure {
913 private:
914 int _index;
915 const char* _prefix;
916
917 public:
918 PrintAllRefsOopClosure(const char* prefix) : _index(0), _prefix(prefix) {}
919
920 private:
921 template <class T>
922 inline void do_oop_work(T* p) {
923 oop o = oopDesc::load_decode_heap_oop(p);
924 if (o != NULL) {
925 if (ShenandoahHeap::heap()->is_in(o) && o->is_oop()) {
926 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT")-> "PTR_FORMAT" (marked: %s) (%s "PTR_FORMAT")",
927 _prefix, _index,
928 p2i(p), p2i(o),
929 BOOL_TO_STR(ShenandoahHeap::heap()->is_marked_complete(o)),
930 o->klass()->internal_name(), p2i(o->klass()));
931 } else {
932 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT" dirty -> "PTR_FORMAT" (not in heap, possibly corrupted or dirty)",
933 _prefix, _index,
934 p2i(p), p2i(o));
935 }
936 } else {
937 tty->print_cr("%s "INT32_FORMAT" ("PTR_FORMAT") -> "PTR_FORMAT, _prefix, _index, p2i(p), p2i((HeapWord*) o));
938 }
939 _index++;
940 }
941
942 public:
943 void do_oop(oop* p) {
944 do_oop_work(p);
945 }
946
947 void do_oop(narrowOop* p) {
948 do_oop_work(p);
949 }
950
951 };
952
953 class PrintAllRefsObjectClosure : public ObjectClosure {
954 const char* _prefix;
955
956 public:
957 PrintAllRefsObjectClosure(const char* prefix) : _prefix(prefix) {}
958
959 void do_object(oop p) {
960 if (ShenandoahHeap::heap()->is_in(p)) {
961 tty->print_cr("%s object "PTR_FORMAT" (marked: %s) (%s "PTR_FORMAT") refers to:",
962 _prefix, p2i(p),
963 BOOL_TO_STR(ShenandoahHeap::heap()->is_marked_complete(p)),
964 p->klass()->internal_name(), p2i(p->klass()));
965 PrintAllRefsOopClosure cl(_prefix);
966 p->oop_iterate(&cl);
967 }
968 }
969 };
970
971 void ShenandoahHeap::print_all_refs(const char* prefix) {
972 tty->print_cr("printing all references in the heap");
973 tty->print_cr("root references:");
974
975 ensure_parsability(false);
976
977 PrintAllRefsOopClosure cl(prefix);
978 roots_iterate(&cl);
979
980 tty->print_cr("heap references:");
981 PrintAllRefsObjectClosure cl2(prefix);
982 object_iterate(&cl2);
983 }
984
985 class VerifyAfterMarkingOopClosure: public ExtendedOopClosure {
986 private:
987 ShenandoahHeap* _heap;
988
989 public:
990 VerifyAfterMarkingOopClosure() :
991 _heap(ShenandoahHeap::heap()) { }
992
993 private:
994 template <class T>
995 inline void do_oop_work(T* p) {
996 oop o = oopDesc::load_decode_heap_oop(p);
997 if (o != NULL) {
998 if (! _heap->is_marked_complete(o)) {
999 _heap->print_heap_regions();
1000 _heap->print_all_refs("post-mark");
1001 tty->print_cr("oop not marked, although referrer is marked: "PTR_FORMAT": in_heap: %s, is_marked: %s",
1002 p2i((HeapWord*) o), BOOL_TO_STR(_heap->is_in(o)), BOOL_TO_STR(_heap->is_marked_complete(o)));
1003 _heap->print_heap_locations((HeapWord*) o, (HeapWord*) o + o->size());
1004
1005 tty->print_cr("oop class: %s", o->klass()->internal_name());
1006 if (_heap->is_in(p)) {
1007 oop referrer = oop(_heap->heap_region_containing(p)->block_start_const(p));
1008 tty->print_cr("Referrer starts at addr "PTR_FORMAT, p2i((HeapWord*) referrer));
1009 referrer->print();
1010 _heap->print_heap_locations((HeapWord*) referrer, (HeapWord*) referrer + referrer->size());
1011 }
1012 tty->print_cr("heap region containing object:");
1013 _heap->heap_region_containing(o)->print();
1014 tty->print_cr("heap region containing referrer:");
1015 _heap->heap_region_containing(p)->print();
1016 tty->print_cr("heap region containing forwardee:");
1017 _heap->heap_region_containing(oopDesc::bs()->read_barrier(o))->print();
1018 }
1019 assert(o->is_oop(), "oop must be an oop");
1020 assert(Metaspace::contains(o->klass()), "klass pointer must go to metaspace");
1021 if (! oopDesc::unsafe_equals(o, oopDesc::bs()->read_barrier(o))) {
1022 tty->print_cr("oops has forwardee: p: "PTR_FORMAT" (%s), o = "PTR_FORMAT" (%s), new-o: "PTR_FORMAT" (%s)",
1023 p2i(p),
1024 BOOL_TO_STR(_heap->in_collection_set(p)),
1025 p2i(o),
1026 BOOL_TO_STR(_heap->in_collection_set(o)),
1027 p2i((HeapWord*) oopDesc::bs()->read_barrier(o)),
1028 BOOL_TO_STR(_heap->in_collection_set(oopDesc::bs()->read_barrier(o))));
1029 tty->print_cr("oop class: %s", o->klass()->internal_name());
1030 }
1031 assert(oopDesc::unsafe_equals(o, oopDesc::bs()->read_barrier(o)), "oops must not be forwarded");
1032 assert(! _heap->in_collection_set(o), "references must not point to dirty heap regions");
1033 assert(_heap->is_marked_complete(o), "live oops must be marked current");
1034 }
1035 }
1036
1037 public:
1038 void do_oop(oop* p) {
1039 do_oop_work(p);
1040 }
1041
1042 void do_oop(narrowOop* p) {
1043 do_oop_work(p);
1044 }
1045
1046 };
1047
1048 void ShenandoahHeap::verify_heap_after_marking() {
1049
1050 verify_heap_size_consistency();
1051
1052 log_trace(gc)("verifying heap after marking");
1053
1054 VerifyAfterMarkingOopClosure cl;
1055 roots_iterate(&cl);
1056 ObjectToOopClosure objs(&cl);
1057 object_iterate(&objs);
1058 }
1059
1060
1061 void ShenandoahHeap::reclaim_humongous_region_at(ShenandoahHeapRegion* r) {
1062 assert(r->is_humongous_start(), "reclaim regions starting with the first one");
1063
1064 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size());
1065 size_t size = humongous_obj->size() + BrooksPointer::word_size();
1066 size_t required_regions = ShenandoahHumongous::required_regions(size * HeapWordSize);
1067 size_t index = r->region_number();
1068
1069
1070 assert(!r->has_live(), "liveness must be zero");
1071
1072 for(size_t i = 0; i < required_regions; i++) {
1073
1074 ShenandoahHeapRegion* region = _ordered_regions->get(index++);
1075
1076 assert((region->is_humongous_start() || region->is_humongous_continuation()),
1077 "expect correct humongous start or continuation");
1078
1079 if (log_is_enabled(Debug, gc, humongous)) {
1080 log_debug(gc, humongous)("reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
1081 ResourceMark rm;
1082 outputStream* out = Log(gc, humongous)::debug_stream();
1083 region->print_on(out);
1084 }
1085
1086 region->recycle();
1087 ShenandoahHeap::heap()->decrease_used(ShenandoahHeapRegion::region_size_bytes());
1088 }
1089 }
1090
1091 class ShenandoahReclaimHumongousRegionsClosure : public ShenandoahHeapRegionClosure {
1092
1093 bool doHeapRegion(ShenandoahHeapRegion* r) {
1094 ShenandoahHeap* heap = ShenandoahHeap::heap();
1095
1096 if (r->is_humongous_start()) {
1097 oop humongous_obj = oop(r->bottom() + BrooksPointer::word_size());
1098 if (! heap->is_marked_complete(humongous_obj)) {
1099
1100 heap->reclaim_humongous_region_at(r);
1101 }
1102 }
1103 return false;
1104 }
1105 };
1106
1107 #ifdef ASSERT
1108 class CheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1109 bool doHeapRegion(ShenandoahHeapRegion* r) {
1110 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1111 return false;
1112 }
1113 };
1114 #endif
1115
1116 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1117 assert(_ordered_regions->get(0)->region_number() == 0, "FIXME CHF. FIXME CHF!");
1118
1119 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1120
1121 if (!cancelled_concgc()) {
1122
1123 recycle_dirty_regions();
1124
1125 ensure_parsability(true);
1126
1127 if (UseShenandoahMatrix && PrintShenandoahMatrix) {
1128 outputStream* log = Log(gc)::info_stream();
1129 connection_matrix()->print_on(log);
1130 }
1131
1132 if (ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix)) {
1133 verify_heap_reachable_at_safepoint();
1134 }
1135
1136 #ifdef ASSERT
1137 if (ShenandoahVerify) {
1138 verify_heap_after_marking();
1139 }
1140 #endif
1141
1142 // NOTE: This needs to be done during a stop the world pause, because
1143 // putting regions into the collection set concurrently with Java threads
1144 // will create a race. In particular, acmp could fail because when we
1145 // resolve the first operand, the containing region might not yet be in
1146 // the collection set, and thus return the original oop. When the 2nd
1147 // operand gets resolved, the region could be in the collection set
1148 // and the oop gets evacuated. If both operands have originally been
1149 // the same, we get false negatives.
1150
1151 {
1152 ShenandoahHeapLock lock(this);
1153 _collection_set->clear();
1154 _free_regions->clear();
1155
1156 ShenandoahReclaimHumongousRegionsClosure reclaim;
1157 heap_region_iterate(&reclaim);
1158
1159 #ifdef ASSERT
1160 CheckCollectionSetClosure ccsc;
1161 _ordered_regions->heap_region_iterate(&ccsc);
1162 #endif
1163
1164 _shenandoah_policy->choose_collection_set(_collection_set);
1165
1166 _shenandoah_policy->choose_free_set(_free_regions);
1167 }
1168
1169 _bytes_allocated_since_cm = 0;
1170
1171 Universe::update_heap_info_at_gc();
1172 }
1173 }
1174
1175
1176 class RetireTLABClosure : public ThreadClosure {
1177 private:
1178 bool _retire;
1179
1180 public:
1181 RetireTLABClosure(bool retire) : _retire(retire) {
1182 }
1183
1184 void do_thread(Thread* thread) {
1185 thread->gclab().make_parsable(_retire);
1186 }
1187 };
1188
1189 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1190 if (UseTLAB) {
1191 CollectedHeap::ensure_parsability(retire_tlabs);
1192 RetireTLABClosure cl(retire_tlabs);
1193 Threads::threads_do(&cl);
1194 }
1195 }
1196
1197 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
1198 private:
1199 ShenandoahHeap* _heap;
1200 Thread* _thread;
1201 public:
1202 ShenandoahEvacuateUpdateRootsClosure() :
1203 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
1204 }
1205
1206 private:
1207 template <class T>
1208 void do_oop_work(T* p) {
1209 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
1210
1211 T o = oopDesc::load_heap_oop(p);
1212 if (! oopDesc::is_null(o)) {
1213 oop obj = oopDesc::decode_heap_oop_not_null(o);
1214 if (_heap->in_collection_set(obj)) {
1215 assert(_heap->is_marked_complete(obj), "only evacuate marked objects %d %d",
1216 _heap->is_marked_complete(obj), _heap->is_marked_complete(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)));
1217 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1218 if (oopDesc::unsafe_equals(resolved, obj)) {
1219 bool evac;
1220 resolved = _heap->evacuate_object(obj, _thread, evac);
1221 }
1222 oopDesc::encode_store_heap_oop(p, resolved);
1223 }
1224 }
1225 #ifdef ASSERT
1226 else {
1227 // tty->print_cr("not updating root at: "PTR_FORMAT" with object: "PTR_FORMAT", is_in_heap: %s, is_in_cset: %s, is_marked: %s",
1228 // p2i(p),
1229 // p2i((HeapWord*) obj),
1230 // BOOL_TO_STR(_heap->is_in(obj)),
1231 // BOOL_TO_STR(_heap->in_cset_fast_test(obj)),
1232 // BOOL_TO_STR(_heap->is_marked_complete(obj)));
1233 }
1234 #endif
1235 }
1236
1237 public:
1238 void do_oop(oop* p) {
1239 do_oop_work(p);
1240 }
1241 void do_oop(narrowOop* p) {
1242 do_oop_work(p);
1243 }
1244 };
1245
1246 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1247 ShenandoahRootEvacuator* _rp;
1248 public:
1249
1250 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1251 AbstractGangTask("Shenandoah evacuate and update roots"),
1252 _rp(rp)
1253 {
1254 // Nothing else to do.
1255 }
1256
1257 void work(uint worker_id) {
1258 ShenandoahEvacuateUpdateRootsClosure cl;
1259 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1260
1261 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1262 }
1263 };
1264
1265 class ShenandoahFixRootsTask : public AbstractGangTask {
1266 ShenandoahRootEvacuator* _rp;
1267 public:
1268
1269 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1270 AbstractGangTask("Shenandoah update roots"),
1271 _rp(rp)
1272 {
1273 // Nothing else to do.
1274 }
1275
1276 void work(uint worker_id) {
1277 SCMUpdateRefsClosure cl;
1278 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1279
1280 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1281 }
1282 };
1283 void ShenandoahHeap::evacuate_and_update_roots() {
1284
1285 COMPILER2_PRESENT(DerivedPointerTable::clear());
1286
1287 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1288
1289 {
1290 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahCollectorPolicy::init_evac);
1291 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1292 workers()->run_task(&roots_task);
1293 }
1294
1295 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1296
1297 if (cancelled_concgc()) {
1298 // If initial evacuation has been cancelled, we need to update all references
1299 // after all workers have finished. Otherwise we might run into the following problem:
1300 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1301 // GC thread 2 evacuates the same object X to to-space
1302 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1303 // clear() and update_pointers() must always be called in pairs,
1304 // cannot nest with above clear()/update_pointers().
1305 COMPILER2_PRESENT(DerivedPointerTable::clear());
1306 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahCollectorPolicy::init_evac);
1307 ShenandoahFixRootsTask update_roots_task(&rp);
1308 workers()->run_task(&update_roots_task);
1309 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1310 }
1311
1312 #ifdef ASSERT
1313 {
1314 AssertToSpaceClosure cl;
1315 CodeBlobToOopClosure code_cl(&cl, !CodeBlobToOopClosure::FixRelocations);
1316 ShenandoahRootEvacuator rp(this, 1);
1317 rp.process_evacuate_roots(&cl, &code_cl, 0);
1318 }
1319 #endif
1320 }
1321
1322
1323 void ShenandoahHeap::do_evacuation() {
1324
1325 parallel_evacuate();
1326
1327 if (ShenandoahVerify && ! cancelled_concgc()) {
1328 VM_ShenandoahVerifyHeapAfterEvacuation verify_after_evacuation;
1329 if (Thread::current()->is_VM_thread()) {
1330 verify_after_evacuation.doit();
1331 } else {
1332 VMThread::execute(&verify_after_evacuation);
1333 }
1334 }
1335
1336 }
1337
1338 void ShenandoahHeap::parallel_evacuate() {
1339 log_develop_trace(gc)("starting parallel_evacuate");
1340
1341 _shenandoah_policy->record_phase_start(ShenandoahCollectorPolicy::conc_evac);
1342
1343 if (log_is_enabled(Trace, gc, region)) {
1344 ResourceMark rm;
1345 outputStream *out = Log(gc, region)::trace_stream();
1346 out->print("Printing all available regions");
1347 print_heap_regions(out);
1348 }
1349
1350 if (log_is_enabled(Trace, gc, cset)) {
1351 ResourceMark rm;
1352 outputStream *out = Log(gc, cset)::trace_stream();
1353 out->print("Printing collection set which contains "SIZE_FORMAT" regions:\n", _collection_set->count());
1354 _collection_set->print(out);
1355
1356 out->print("Printing free set which contains "SIZE_FORMAT" regions:\n", _free_regions->count());
1357 _free_regions->print(out);
1358 }
1359
1360 ParallelEvacuationTask evacuationTask = ParallelEvacuationTask(this, _collection_set);
1361
1362
1363 workers()->run_task(&evacuationTask);
1364
1365 if (log_is_enabled(Trace, gc, cset)) {
1366 ResourceMark rm;
1367 outputStream *out = Log(gc, cset)::trace_stream();
1368 out->print("Printing postgc collection set which contains "SIZE_FORMAT" regions:\n",
1369 _collection_set->count());
1370
1371 _collection_set->print(out);
1372
1373 out->print("Printing postgc free regions which contain "SIZE_FORMAT" free regions:\n",
1374 _free_regions->count());
1375 _free_regions->print(out);
1376
1377 }
1378
1379 if (log_is_enabled(Trace, gc, region)) {
1380 ResourceMark rm;
1381 outputStream *out = Log(gc, region)::trace_stream();
1382 out->print_cr("all regions after evacuation:");
1383 print_heap_regions(out);
1384 }
1385
1386 _shenandoah_policy->record_phase_end(ShenandoahCollectorPolicy::conc_evac);
1387 }
1388
1389 class VerifyEvacuationClosure: public ExtendedOopClosure {
1390 private:
1391 ShenandoahHeap* _heap;
1392 ShenandoahHeapRegion* _from_region;
1393
1394 public:
1395 VerifyEvacuationClosure(ShenandoahHeapRegion* from_region) :
1396 _heap(ShenandoahHeap::heap()), _from_region(from_region) { }
1397 private:
1398 template <class T>
1399 inline void do_oop_work(T* p) {
1400 oop heap_oop = oopDesc::load_decode_heap_oop(p);
1401 if (! oopDesc::is_null(heap_oop)) {
1402 guarantee(! _from_region->is_in(heap_oop), "no references to from-region allowed after evacuation: "PTR_FORMAT, p2i((HeapWord*) heap_oop));
1403 }
1404 }
1405
1406 public:
1407 void do_oop(oop* p) {
1408 do_oop_work(p);
1409 }
1410
1411 void do_oop(narrowOop* p) {
1412 do_oop_work(p);
1413 }
1414
1415 };
1416
1417 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1418
1419 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1420
1421 CodeBlobToOopClosure blobsCl(cl, false);
1422 CLDToOopClosure cldCl(cl);
1423
1424 ShenandoahRootProcessor rp(this, 1);
1425 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, 0);
1426 }
1427
1428 void ShenandoahHeap::verify_evacuation(ShenandoahHeapRegion* from_region) {
1429
1430 VerifyEvacuationClosure rootsCl(from_region);
1431 roots_iterate(&rootsCl);
1432
1433 }
1434
1435 bool ShenandoahHeap::supports_tlab_allocation() const {
1436 return true;
1437 }
1438
1439
1440 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1441 size_t idx = _free_regions->current_index();
1442 ShenandoahHeapRegion* current = _free_regions->get_or_null(idx);
1443 if (current == NULL) {
1444 return 0;
1445 } else if (current->free() > MinTLABSize) {
1446 // Current region has enough space left, can use it.
1447 return current->free();
1448 } else {
1449 // No more space in current region, we will take next free region
1450 // on the next TLAB allocation.
1451 return ShenandoahHeapRegion::region_size_bytes();
1452 }
1453 }
1454
1455 size_t ShenandoahHeap::max_tlab_size() const {
1456 return ShenandoahHeapRegion::region_size_bytes();
1457 }
1458
1459 class ResizeGCLABClosure : public ThreadClosure {
1460 public:
1461 void do_thread(Thread* thread) {
1462 thread->gclab().resize();
1463 }
1464 };
1465
1466 void ShenandoahHeap::resize_all_tlabs() {
1467 CollectedHeap::resize_all_tlabs();
1468
1469 ResizeGCLABClosure cl;
1470 Threads::threads_do(&cl);
1471 }
1472
1473 class AccumulateStatisticsGCLABClosure : public ThreadClosure {
1474 public:
1475 void do_thread(Thread* thread) {
1476 thread->gclab().accumulate_statistics();
1477 thread->gclab().initialize_statistics();
1478 }
1479 };
1480
1481 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1482 AccumulateStatisticsGCLABClosure cl;
1483 Threads::threads_do(&cl);
1484 }
1485
1486 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1487 return true;
1488 }
1489
1490 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1491 // Overridden to do nothing.
1492 return new_obj;
1493 }
1494
1495 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1496 return true;
1497 }
1498
1499 bool ShenandoahHeap::card_mark_must_follow_store() const {
1500 return false;
1501 }
1502
1503 void ShenandoahHeap::collect(GCCause::Cause cause) {
1504 assert(cause != GCCause::_gc_locker, "no JNI critical callback");
1505 if (GCCause::is_user_requested_gc(cause)) {
1506 if (! DisableExplicitGC) {
1507 _concurrent_gc_thread->do_full_gc(cause);
1508 }
1509 } else if (cause == GCCause::_allocation_failure) {
1510 collector_policy()->set_should_clear_all_soft_refs(true);
1511 _concurrent_gc_thread->do_full_gc(cause);
1512 }
1513 }
1514
1515 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1516 //assert(false, "Shouldn't need to do full collections");
1517 }
1518
1519 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1520 Unimplemented();
1521 return NULL;
1522
1523 }
1524
1525 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1526 return _shenandoah_policy;
1527 }
1528
1529
1530 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1531 Space* sp = heap_region_containing(addr);
1532 if (sp != NULL) {
1533 return sp->block_start(addr);
1534 }
1535 return NULL;
1536 }
1537
1538 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1539 Space* sp = heap_region_containing(addr);
1540 assert(sp != NULL, "block_size of address outside of heap");
1541 return sp->block_size(addr);
1542 }
1543
1544 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1545 Space* sp = heap_region_containing(addr);
1546 return sp->block_is_obj(addr);
1547 }
1548
1549 jlong ShenandoahHeap::millis_since_last_gc() {
1550 return 0;
1551 }
1552
1553 void ShenandoahHeap::prepare_for_verify() {
1554 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1555 ensure_parsability(false);
1556 }
1557 }
1558
1559 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1560 workers()->print_worker_threads_on(st);
1561 }
1562
1563 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1564 workers()->threads_do(tcl);
1565 }
1566
1567 void ShenandoahHeap::print_tracing_info() const {
1568 if (log_is_enabled(Info, gc, stats)) {
1569 ResourceMark rm;
1570 outputStream* out = Log(gc, stats)::info_stream();
1571 _shenandoah_policy->print_tracing_info(out);
1572 }
1573 }
1574
1575 class ShenandoahVerifyRootsClosure: public ExtendedOopClosure {
1576 private:
1577 ShenandoahHeap* _heap;
1578 VerifyOption _vo;
1579 bool _failures;
1580 public:
1581 // _vo == UsePrevMarking -> use "prev" marking information,
1582 // _vo == UseNextMarking -> use "next" marking information,
1583 // _vo == UseMarkWord -> use mark word from object header.
1584 ShenandoahVerifyRootsClosure(VerifyOption vo) :
1585 _heap(ShenandoahHeap::heap()),
1586 _vo(vo),
1587 _failures(false) { }
1588
1589 bool failures() { return _failures; }
1590
1591 private:
1592 template <class T>
1593 inline void do_oop_work(T* p) {
1594 oop obj = oopDesc::load_decode_heap_oop(p);
1595 if (! oopDesc::is_null(obj) && ! obj->is_oop()) {
1596 { // Just for debugging.
1597 tty->print_cr("Root location "PTR_FORMAT
1598 "verified "PTR_FORMAT, p2i(p), p2i((void*) obj));
1599 // obj->print_on(tty);
1600 }
1601 }
1602 guarantee(obj->is_oop_or_null(), "is oop or null");
1603 }
1604
1605 public:
1606 void do_oop(oop* p) {
1607 do_oop_work(p);
1608 }
1609
1610 void do_oop(narrowOop* p) {
1611 do_oop_work(p);
1612 }
1613
1614 };
1615
1616 class ShenandoahVerifyHeapClosure: public ObjectClosure {
1617 private:
1618 ShenandoahVerifyRootsClosure _rootsCl;
1619 public:
1620 ShenandoahVerifyHeapClosure(ShenandoahVerifyRootsClosure rc) :
1621 _rootsCl(rc) {};
1622
1623 void do_object(oop p) {
1624 _rootsCl.do_oop(&p);
1625 }
1626 };
1627
1628 void ShenandoahHeap::verify(VerifyOption vo) {
1629 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1630
1631 ShenandoahVerifyRootsClosure rootsCl(vo);
1632
1633 assert(Thread::current()->is_VM_thread(),
1634 "Expected to be executed serially by the VM thread at this point");
1635
1636 roots_iterate(&rootsCl);
1637
1638 bool failures = rootsCl.failures();
1639 log_trace(gc)("verify failures: %s", BOOL_TO_STR(failures));
1640
1641 ShenandoahVerifyHeapClosure heapCl(rootsCl);
1642
1643 object_iterate(&heapCl);
1644 // TODO: Implement rest of it.
1645 } else {
1646 tty->print("(SKIPPING roots, heapRegions, remset) ");
1647 }
1648 }
1649 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1650 return _free_regions->capacity();
1651 }
1652
1653 class ShenandoahIterateObjectClosureRegionClosure: public ShenandoahHeapRegionClosure {
1654 ObjectClosure* _cl;
1655 public:
1656 ShenandoahIterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
1657 bool doHeapRegion(ShenandoahHeapRegion* r) {
1658 ShenandoahHeap::heap()->marked_object_iterate(r, _cl);
1659 return false;
1660 }
1661 };
1662
1663 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1664 ShenandoahIterateObjectClosureRegionClosure blk(cl);
1665 heap_region_iterate(&blk, false, true);
1666 }
1667
1668 class ShenandoahSafeObjectIterateAdjustPtrsClosure : public MetadataAwareOopClosure {
1669 private:
1670 ShenandoahHeap* _heap;
1671
1672 public:
1673 ShenandoahSafeObjectIterateAdjustPtrsClosure() : _heap(ShenandoahHeap::heap()) {}
1674
1675 private:
1676 template <class T>
1677 inline void do_oop_work(T* p) {
1678 T o = oopDesc::load_heap_oop(p);
1679 if (!oopDesc::is_null(o)) {
1680 oop obj = oopDesc::decode_heap_oop_not_null(o);
1681 oopDesc::encode_store_heap_oop(p, BrooksPointer::forwardee(obj));
1682 }
1683 }
1684 public:
1685 void do_oop(oop* p) {
1686 do_oop_work(p);
1687 }
1688 void do_oop(narrowOop* p) {
1689 do_oop_work(p);
1690 }
1691 };
1692
1693 class ShenandoahSafeObjectIterateAndUpdate : public ObjectClosure {
1694 private:
1695 ObjectClosure* _cl;
1696 public:
1697 ShenandoahSafeObjectIterateAndUpdate(ObjectClosure *cl) : _cl(cl) {}
1698
1699 virtual void do_object(oop obj) {
1700 assert (oopDesc::unsafe_equals(obj, BrooksPointer::forwardee(obj)),
1701 "avoid double-counting: only non-forwarded objects here");
1702
1703 // Fix up the ptrs.
1704 ShenandoahSafeObjectIterateAdjustPtrsClosure adjust_ptrs;
1705 obj->oop_iterate(&adjust_ptrs);
1706
1707 // Can reply the object now:
1708 _cl->do_object(obj);
1709 }
1710 };
1711
1712 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1713 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1714
1715 // Safe iteration does objects only with correct references.
1716 // This is why we skip dirty regions that have stale copies of objects,
1717 // and fix up the pointers in the returned objects.
1718
1719 ShenandoahSafeObjectIterateAndUpdate safe_cl(cl);
1720 ShenandoahIterateObjectClosureRegionClosure blk(&safe_cl);
1721 heap_region_iterate(&blk,
1722 /* skip_dirty_regions = */ true,
1723 /* skip_humongous_continuations = */ true);
1724
1725 _need_update_refs = false; // already updated the references
1726 }
1727
1728 // Apply blk->doHeapRegion() on all committed regions in address order,
1729 // terminating the iteration early if doHeapRegion() returns true.
1730 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_dirty_regions, bool skip_humongous_continuation) const {
1731 for (size_t i = 0; i < _num_regions; i++) {
1732 ShenandoahHeapRegion* current = _ordered_regions->get(i);
1733 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1734 continue;
1735 }
1736 if (skip_dirty_regions && in_collection_set(current)) {
1737 continue;
1738 }
1739 if (blk->doHeapRegion(current)) {
1740 return;
1741 }
1742 }
1743 }
1744
1745 class ClearLivenessClosure : public ShenandoahHeapRegionClosure {
1746 ShenandoahHeap* sh;
1747 public:
1748 ClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) { }
1749
1750 bool doHeapRegion(ShenandoahHeapRegion* r) {
1751 r->clear_live_data();
1752 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1753 return false;
1754 }
1755 };
1756
1757 void ShenandoahHeap::start_concurrent_marking() {
1758
1759 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::accumulate_stats);
1760 accumulate_statistics_all_tlabs();
1761 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::accumulate_stats);
1762
1763 set_concurrent_mark_in_progress(true);
1764 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1765 if (UseTLAB) {
1766 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::make_parsable);
1767 ensure_parsability(true);
1768 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::make_parsable);
1769 }
1770
1771 _shenandoah_policy->record_bytes_allocated(_bytes_allocated_since_cm);
1772 _used_start_gc = used();
1773
1774 #ifdef ASSERT
1775 if (ShenandoahDumpHeapBeforeConcurrentMark) {
1776 ensure_parsability(false);
1777 print_all_refs("pre-mark");
1778 }
1779 #endif
1780
1781 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::clear_liveness);
1782 ClearLivenessClosure clc(this);
1783 heap_region_iterate(&clc);
1784 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::clear_liveness);
1785
1786 if (UseShenandoahMatrix) {
1787 connection_matrix()->clear_all();
1788 }
1789 // print_all_refs("pre -mark");
1790
1791 // oopDesc::_debug = true;
1792
1793 // Make above changes visible to worker threads
1794 OrderAccess::fence();
1795
1796 shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::scan_roots);
1797 concurrentMark()->init_mark_roots();
1798 shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::scan_roots);
1799
1800 // print_all_refs("pre-mark2");
1801 }
1802
1803 class VerifyAfterEvacuationClosure : public ExtendedOopClosure {
1804
1805 ShenandoahHeap* _sh;
1806
1807 public:
1808 VerifyAfterEvacuationClosure() : _sh ( ShenandoahHeap::heap() ) {}
1809
1810 template<class T> void do_oop_nv(T* p) {
1811 T heap_oop = oopDesc::load_heap_oop(p);
1812 if (!oopDesc::is_null(heap_oop)) {
1813 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1814 guarantee(_sh->in_collection_set(obj) == (! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))),
1815 "forwarded objects can only exist in dirty (from-space) regions is_dirty: %s, is_forwarded: %s obj-klass: %s, marked: %s",
1816 BOOL_TO_STR(_sh->in_collection_set(obj)),
1817 BOOL_TO_STR(! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))),
1818 obj->klass()->external_name(),
1819 BOOL_TO_STR(_sh->is_marked_complete(obj))
1820 );
1821 obj = oopDesc::bs()->read_barrier(obj);
1822 guarantee(! _sh->in_collection_set(obj), "forwarded oops must not point to dirty regions");
1823 guarantee(obj->is_oop(), "is_oop");
1824 guarantee(Metaspace::contains(obj->klass()), "klass pointer must go to metaspace");
1825 }
1826 }
1827
1828 void do_oop(oop* p) { do_oop_nv(p); }
1829 void do_oop(narrowOop* p) { do_oop_nv(p); }
1830
1831 };
1832
1833 void ShenandoahHeap::verify_heap_after_evacuation() {
1834
1835 verify_heap_size_consistency();
1836
1837 ensure_parsability(false);
1838
1839 VerifyAfterEvacuationClosure cl;
1840 roots_iterate(&cl);
1841
1842 ObjectToOopClosure objs(&cl);
1843 object_iterate(&objs);
1844
1845 }
1846
1847 void ShenandoahHeap::swap_mark_bitmaps() {
1848 // Swap bitmaps.
1849 CMBitMap* tmp1 = _complete_mark_bit_map;
1850 _complete_mark_bit_map = _next_mark_bit_map;
1851 _next_mark_bit_map = tmp1;
1852
1853 // Swap top-at-mark-start pointers
1854 HeapWord** tmp2 = _complete_top_at_mark_starts;
1855 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1856 _next_top_at_mark_starts = tmp2;
1857
1858 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1859 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1860 _next_top_at_mark_starts_base = tmp3;
1861 }
1862
1863 class VerifyReachableHeapClosure : public ExtendedOopClosure {
1864 private:
1865 SCMObjToScanQueue* _queue;
1866 ShenandoahHeap* _heap;
1867 CMBitMap* _map;
1868 bool _check_matrix;
1869 oop _obj;
1870 public:
1871 VerifyReachableHeapClosure(SCMObjToScanQueue* queue, CMBitMap* map, bool check_matrix) :
1872 _queue(queue), _heap(ShenandoahHeap::heap()), _map(map), _check_matrix(check_matrix) {};
1873 template <class T>
1874 void do_oop_work(T* p) {
1875 T o = oopDesc::load_heap_oop(p);
1876 if (!oopDesc::is_null(o)) {
1877 oop obj = oopDesc::decode_heap_oop_not_null(o);
1878 guarantee(check_obj_alignment(obj), "sanity");
1879
1880 guarantee(!oopDesc::is_null(obj), "sanity");
1881 guarantee(_heap->is_in(obj), "sanity");
1882
1883 oop forw = BrooksPointer::forwardee(obj);
1884 guarantee(!oopDesc::is_null(forw), "sanity");
1885 guarantee(_heap->is_in(forw), "sanity");
1886
1887 guarantee(oopDesc::unsafe_equals(obj, forw), "should not be forwarded");
1888
1889 if (_check_matrix) {
1890 size_t from_idx = _heap->heap_region_index_containing(p);
1891 size_t to_idx = _heap->heap_region_index_containing(obj);
1892 if (!_heap->connection_matrix()->is_connected(from_idx, to_idx)) {
1893 tty->print_cr("from-obj: ");
1894 _obj->print_on(tty);
1895 tty->print_cr("to-obj:");
1896 obj->print_on(tty);
1897 tty->print_cr("from-obj allocated after mark: %s", BOOL_TO_STR(_heap->allocated_after_complete_mark_start((HeapWord*) _obj)));
1898 tty->print_cr("to-obj allocated after mark: %s", BOOL_TO_STR(_heap->allocated_after_complete_mark_start((HeapWord*) obj)));
1899 tty->print_cr("from-obj marked: %s", BOOL_TO_STR(_heap->is_marked_complete(_obj)));
1900 tty->print_cr("to-obj marked: %s", BOOL_TO_STR(_heap->is_marked_complete(obj)));
1901 tty->print_cr("from-idx: " SIZE_FORMAT ", to-idx: " SIZE_FORMAT, from_idx, to_idx);
1902
1903 oop fwd_from = BrooksPointer::forwardee(_obj);
1904 oop fwd_to = BrooksPointer::forwardee(obj);
1905 tty->print_cr("from-obj forwardee: " PTR_FORMAT, p2i(fwd_from));
1906 tty->print_cr("to-obj forwardee: " PTR_FORMAT, p2i(fwd_to));
1907 tty->print_cr("forward(from-obj) marked: %s", BOOL_TO_STR(_heap->is_marked_complete(fwd_from)));
1908 tty->print_cr("forward(to-obj) marked: %s", BOOL_TO_STR(_heap->is_marked_complete(fwd_to)));
1909 size_t fwd_from_idx = _heap->heap_region_index_containing(fwd_from);
1910 size_t fwd_to_idx = _heap->heap_region_index_containing(fwd_to);
1911 tty->print_cr("forward(from-idx): " SIZE_FORMAT ", forward(to-idx): " SIZE_FORMAT, fwd_from_idx, fwd_to_idx);
1912 tty->print_cr("forward(from) connected with forward(to)? %s", BOOL_TO_STR(_heap->connection_matrix()->is_connected(fwd_from_idx, fwd_to_idx)));
1913 }
1914 guarantee(oopDesc::unsafe_equals(ShenandoahBarrierSet::resolve_oop_static_not_null(obj), obj), "polizeilich verboten");
1915 guarantee(_heap->connection_matrix()->is_connected(from_idx, to_idx), "must be connected");
1916 }
1917
1918 if (_map->parMark((HeapWord*) obj)) {
1919 _queue->push(SCMTask(obj));
1920 }
1921 }
1922 }
1923
1924 void do_oop(oop* p) { do_oop_work(p); }
1925 void do_oop(narrowOop* p) { do_oop_work(p); }
1926 void set_obj(oop o) { _obj = o; }
1927 };
1928
1929 void ShenandoahHeap::verify_heap_reachable_at_safepoint() {
1930 guarantee(SafepointSynchronize::is_at_safepoint(), "only when nothing else happens");
1931 guarantee(ShenandoahVerify || (UseShenandoahMatrix && VerifyShenandoahMatrix),
1932 "only when these are enabled, and bitmap is initialized in ShenandoahHeap::initialize");
1933
1934 OrderAccess::fence();
1935 ensure_parsability(false);
1936
1937 // Allocate temporary bitmap for storing marking wavefront:
1938 MemRegion mr = MemRegion(_verification_bit_map.startWord(), _verification_bit_map.endWord());
1939 _verification_bit_map.clear_range_large(mr);
1940
1941 // Initialize a single queue
1942 SCMObjToScanQueue* q = new SCMObjToScanQueue();
1943 q->initialize();
1944
1945 // Scan root set
1946 ShenandoahRootProcessor rp(this, 1);
1947
1948 {
1949 VerifyReachableHeapClosure cl(q, &_verification_bit_map, false);
1950 CLDToOopClosure cld_cl(&cl);
1951 CodeBlobToOopClosure code_cl(&cl, ! CodeBlobToOopClosure::FixRelocations);
1952 rp.process_all_roots(&cl, &cl, &cld_cl, &code_cl, 0);
1953 }
1954
1955 // Finish the scan
1956 {
1957 VerifyReachableHeapClosure cl(q, &_verification_bit_map, UseShenandoahMatrix && VerifyShenandoahMatrix);
1958 SCMTask task;
1959 while ((q->pop_buffer(task) ||
1960 q->pop_local(task) ||
1961 q->pop_overflow(task))) {
1962 oop obj = task.obj();
1963 assert(!oopDesc::is_null(obj), "must not be null");
1964 cl.set_obj(obj);
1965 obj->oop_iterate(&cl);
1966 }
1967 }
1968
1969 // Clean up!
1970 delete(q);
1971 }
1972
1973 void ShenandoahHeap::stop_concurrent_marking() {
1974 assert(concurrent_mark_in_progress(), "How else could we get here?");
1975 if (! cancelled_concgc()) {
1976 // If we needed to update refs, and concurrent marking has been cancelled,
1977 // we need to finish updating references.
1978 set_need_update_refs(false);
1979 swap_mark_bitmaps();
1980 }
1981 set_concurrent_mark_in_progress(false);
1982
1983 if (log_is_enabled(Trace, gc, region)) {
1984 ResourceMark rm;
1985 outputStream* out = Log(gc, region)::trace_stream();
1986 print_heap_regions(out);
1987 }
1988
1989 }
1990
1991 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1992 _concurrent_mark_in_progress = in_progress ? 1 : 0;
1993 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1994 }
1995
1996 void ShenandoahHeap::set_evacuation_in_progress_concurrently(bool in_progress) {
1997 // Note: it is important to first release the _evacuation_in_progress flag here,
1998 // so that Java threads can get out of oom_during_evacuation() and reach a safepoint,
1999 // in case a VM task is pending.
2000 set_evacuation_in_progress(in_progress);
2001 MutexLocker mu(Threads_lock);
2002 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
2003 }
2004
2005 void ShenandoahHeap::set_evacuation_in_progress_at_safepoint(bool in_progress) {
2006 assert(SafepointSynchronize::is_at_safepoint(), "Only call this at safepoint");
2007 set_evacuation_in_progress(in_progress);
2008 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
2009 }
2010
2011 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2012 _evacuation_in_progress = in_progress ? 1 : 0;
2013 OrderAccess::fence();
2014 }
2015
2016 void ShenandoahHeap::verify_copy(oop p,oop c){
2017 assert(! oopDesc::unsafe_equals(p, oopDesc::bs()->read_barrier(p)), "forwarded correctly");
2018 assert(oopDesc::unsafe_equals(oopDesc::bs()->read_barrier(p), c), "verify pointer is correct");
2019 if (p->klass() != c->klass()) {
2020 print_heap_regions();
2021 }
2022 assert(p->klass() == c->klass(), "verify class p-size: "INT32_FORMAT" c-size: "INT32_FORMAT, p->size(), c->size());
2023 assert(p->size() == c->size(), "verify size");
2024 // Object may have been locked between copy and verification
2025 // assert(p->mark() == c->mark(), "verify mark");
2026 assert(oopDesc::unsafe_equals(c, oopDesc::bs()->read_barrier(c)), "verify only forwarded once");
2027 }
2028
2029 void ShenandoahHeap::oom_during_evacuation() {
2030 log_develop_trace(gc)("Out of memory during evacuation, cancel evacuation, schedule full GC by thread %d",
2031 Thread::current()->osthread()->thread_id());
2032
2033 // We ran out of memory during evacuation. Cancel evacuation, and schedule a full-GC.
2034 collector_policy()->set_should_clear_all_soft_refs(true);
2035 concurrent_thread()->try_set_full_gc();
2036 cancel_concgc(_oom_evacuation);
2037
2038 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
2039 assert(! Threads_lock->owned_by_self()
2040 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here");
2041 log_warning(gc)("OOM during evacuation. Let Java thread wait until evacuation finishes.");
2042 while (_evacuation_in_progress) { // wait.
2043 Thread::current()->_ParkEvent->park(1);
2044 }
2045 }
2046
2047 }
2048
2049 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
2050 // Initialize Brooks pointer for the next object
2051 HeapWord* result = obj + BrooksPointer::word_size();
2052 BrooksPointer::initialize(oop(result));
2053 return result;
2054 }
2055
2056 uint ShenandoahHeap::oop_extra_words() {
2057 return BrooksPointer::word_size();
2058 }
2059
2060 void ShenandoahHeap::grow_heap_by(size_t num_regions) {
2061 size_t old_num_regions = _num_regions;
2062 ensure_new_regions(num_regions);
2063 for (size_t i = 0; i < num_regions; i++) {
2064 size_t new_region_index = i + old_num_regions;
2065 HeapWord* start = ((HeapWord*) base()) + (ShenandoahHeapRegion::region_size_bytes() / HeapWordSize) * new_region_index;
2066 ShenandoahHeapRegion* new_region = new ShenandoahHeapRegion(this, start, ShenandoahHeapRegion::region_size_bytes() / HeapWordSize, new_region_index);
2067
2068 if (log_is_enabled(Trace, gc, region)) {
2069 ResourceMark rm;
2070 outputStream* out = Log(gc, region)::trace_stream();
2071 out->print_cr("allocating new region at index: "SIZE_FORMAT, new_region_index);
2072 new_region->print_on(out);
2073 }
2074
2075 assert(_ordered_regions->active_regions() == new_region->region_number(), "must match");
2076 _ordered_regions->add_region(new_region);
2077 _in_cset_fast_test_base[new_region_index] = false; // Not in cset
2078 _next_top_at_mark_starts_base[new_region_index] = new_region->bottom();
2079 _complete_top_at_mark_starts_base[new_region_index] = new_region->bottom();
2080
2081 _free_regions->add_region(new_region);
2082 }
2083 }
2084
2085 void ShenandoahHeap::ensure_new_regions(size_t new_regions) {
2086
2087 size_t num_regions = _num_regions;
2088 size_t new_num_regions = num_regions + new_regions;
2089 assert(new_num_regions <= _max_regions, "we checked this earlier");
2090
2091 size_t expand_size = new_regions * ShenandoahHeapRegion::region_size_bytes();
2092 log_trace(gc, region)("expanding storage by "SIZE_FORMAT_HEX" bytes, for "SIZE_FORMAT" new regions", expand_size, new_regions);
2093 bool success = _storage.expand_by(expand_size, ShenandoahAlwaysPreTouch);
2094 assert(success, "should always be able to expand by requested size");
2095
2096 _num_regions = new_num_regions;
2097
2098 }
2099
2100 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
2101 _heap(ShenandoahHeap::heap_no_check()) {
2102 }
2103
2104 void ShenandoahForwardedIsAliveClosure::init(ShenandoahHeap* heap) {
2105 _heap = heap;
2106 }
2107
2108 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
2109
2110 assert(_heap != NULL, "sanity");
2111 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
2112 #ifdef ASSERT
2113 if (_heap->concurrent_mark_in_progress()) {
2114 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
2115 }
2116 #endif
2117 assert(!oopDesc::is_null(obj), "null");
2118 return _heap->is_marked_next(obj);
2119 }
2120
2121 void ShenandoahHeap::ref_processing_init() {
2122 MemRegion mr = reserved_region();
2123
2124 isAlive.init(ShenandoahHeap::heap());
2125 assert(_max_workers > 0, "Sanity");
2126
2127 _ref_processor =
2128 new ReferenceProcessor(mr, // span
2129 ParallelRefProcEnabled,
2130 // mt processing
2131 _max_workers,
2132 // degree of mt processing
2133 true,
2134 // mt discovery
2135 _max_workers,
2136 // degree of mt discovery
2137 false,
2138 // Reference discovery is not atomic
2139 &isAlive);
2140 }
2141
2142 size_t ShenandoahHeap::num_regions() {
2143 return _num_regions;
2144 }
2145
2146 size_t ShenandoahHeap::max_regions() {
2147 return _max_regions;
2148 }
2149
2150 GCTracer* ShenandoahHeap::tracer() {
2151 return shenandoahPolicy()->tracer();
2152 }
2153
2154 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2155 return _free_regions->used();
2156 }
2157
2158 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
2159 if (try_cancel_concgc()) {
2160 log_info(gc)("Cancelling concurrent GC: %s", GCCause::to_string(cause));
2161 _shenandoah_policy->report_concgc_cancelled();
2162 }
2163 }
2164
2165 void ShenandoahHeap::cancel_concgc(ShenandoahCancelCause cause) {
2166 if (try_cancel_concgc()) {
2167 log_info(gc)("Cancelling concurrent GC: %s", cancel_cause_to_string(cause));
2168 _shenandoah_policy->report_concgc_cancelled();
2169 }
2170 }
2171
2172 const char* ShenandoahHeap::cancel_cause_to_string(ShenandoahCancelCause cause) {
2173 switch (cause) {
2174 case _oom_evacuation:
2175 return "Out of memory for evacuation";
2176 case _vm_stop:
2177 return "Stopping VM";
2178 default:
2179 return "Unknown";
2180 }
2181 }
2182
2183 uint ShenandoahHeap::max_workers() {
2184 return _max_workers;
2185 }
2186
2187 void ShenandoahHeap::stop() {
2188 // The shutdown sequence should be able to terminate when GC is running.
2189
2190 // Step 1. Notify control thread that we are in shutdown.
2191 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2192 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2193 _concurrent_gc_thread->prepare_for_graceful_shutdown();
2194
2195 // Step 2. Notify GC workers that we are cancelling GC.
2196 cancel_concgc(_vm_stop);
2197
2198 // Step 3. Wait until GC worker exits normally.
2199 _concurrent_gc_thread->stop();
2200 }
2201
2202 void ShenandoahHeap::unload_classes_and_cleanup_tables() {
2203 ShenandoahForwardedIsAliveClosure is_alive;
2204 // Unload classes and purge SystemDictionary.
2205 bool purged_class = SystemDictionary::do_unloading(&is_alive, true);
2206 ParallelCleaningTask unlink_task(&is_alive, true, true, _workers->active_workers(), purged_class);
2207 _workers->run_task(&unlink_task);
2208 ClassLoaderDataGraph::purge();
2209 }
2210
2211 void ShenandoahHeap::set_need_update_refs(bool need_update_refs) {
2212 _need_update_refs = need_update_refs;
2213 }
2214
2215 //fixme this should be in heapregionset
2216 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2217 size_t region_idx = r->region_number() + 1;
2218 ShenandoahHeapRegion* next = _ordered_regions->get(region_idx);
2219 guarantee(next->region_number() == region_idx, "region number must match");
2220 while (next->is_humongous()) {
2221 region_idx = next->region_number() + 1;
2222 next = _ordered_regions->get(region_idx);
2223 guarantee(next->region_number() == region_idx, "region number must match");
2224 }
2225 return next;
2226 }
2227
2228 void ShenandoahHeap::set_region_in_collection_set(size_t region_index, bool b) {
2229 _in_cset_fast_test_base[region_index] = b;
2230 }
2231
2232 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2233 return _monitoring_support;
2234 }
2235
2236 CMBitMap* ShenandoahHeap::complete_mark_bit_map() {
2237 return _complete_mark_bit_map;
2238 }
2239
2240 CMBitMap* ShenandoahHeap::next_mark_bit_map() {
2241 return _next_mark_bit_map;
2242 }
2243
2244 void ShenandoahHeap::add_free_region(ShenandoahHeapRegion* r) {
2245 _free_regions->add_region(r);
2246 }
2247
2248 void ShenandoahHeap::clear_free_regions() {
2249 _free_regions->clear();
2250 }
2251
2252 address ShenandoahHeap::in_cset_fast_test_addr() {
2253 return (address) (ShenandoahHeap::heap()->_in_cset_fast_test);
2254 }
2255
2256 address ShenandoahHeap::cancelled_concgc_addr() {
2257 return (address) &(ShenandoahHeap::heap()->_cancelled_concgc);
2258 }
2259
2260 void ShenandoahHeap::clear_cset_fast_test() {
2261 assert(_in_cset_fast_test_base != NULL, "sanity");
2262 memset(_in_cset_fast_test_base, false,
2263 _in_cset_fast_test_length * sizeof(bool));
2264 }
2265
2266 size_t ShenandoahHeap::conservative_max_heap_alignment() {
2267 return ShenandoahMaxRegionSize;
2268 }
2269
2270 size_t ShenandoahHeap::bytes_allocated_since_cm() {
2271 return _bytes_allocated_since_cm;
2272 }
2273
2274 void ShenandoahHeap::set_bytes_allocated_since_cm(size_t bytes) {
2275 _bytes_allocated_since_cm = bytes;
2276 }
2277
2278 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2279 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2280 _next_top_at_mark_starts[index] = addr;
2281 }
2282
2283 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2284 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2285 return _next_top_at_mark_starts[index];
2286 }
2287
2288 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2289 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2290 _complete_top_at_mark_starts[index] = addr;
2291 }
2292
2293 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2294 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_shift();
2295 return _complete_top_at_mark_starts[index];
2296 }
2297
2298 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2299 _full_gc_in_progress = in_progress;
2300 }
2301
2302 bool ShenandoahHeap::is_full_gc_in_progress() const {
2303 return _full_gc_in_progress;
2304 }
2305
2306 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2307 _update_refs_in_progress = in_progress;
2308 }
2309
2310 bool ShenandoahHeap::is_update_refs_in_progress() const {
2311 return _update_refs_in_progress;
2312 }
2313
2314 class NMethodOopInitializer : public OopClosure {
2315 private:
2316 ShenandoahHeap* _heap;
2317 public:
2318 NMethodOopInitializer() : _heap(ShenandoahHeap::heap()) {
2319 }
2320
2321 private:
2322 template <class T>
2323 inline void do_oop_work(T* p) {
2324 T o = oopDesc::load_heap_oop(p);
2325 if (! oopDesc::is_null(o)) {
2326 oop obj1 = oopDesc::decode_heap_oop_not_null(o);
2327 oop obj2 = oopDesc::bs()->write_barrier(obj1);
2328 if (! oopDesc::unsafe_equals(obj1, obj2)) {
2329 oopDesc::encode_store_heap_oop(p, obj2);
2330 }
2331 }
2332 }
2333
2334 public:
2335 void do_oop(oop* o) {
2336 do_oop_work(o);
2337 }
2338 void do_oop(narrowOop* o) {
2339 do_oop_work(o);
2340 }
2341 };
2342
2343 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2344 NMethodOopInitializer init;
2345 nm->oops_do(&init);
2346 nm->fix_oop_relocations();
2347 }
2348
2349 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2350 }
2351
2352 void ShenandoahHeap::pin_object(oop o) {
2353 heap_region_containing(o)->pin();
2354 }
2355
2356 void ShenandoahHeap::unpin_object(oop o) {
2357 heap_region_containing(o)->unpin();
2358 }
2359
2360
2361 GCTimer* ShenandoahHeap::gc_timer() const {
2362 return _gc_timer;
2363 }
2364
2365 class ShenandoahCountGarbageClosure : public ShenandoahHeapRegionClosure {
2366 private:
2367 size_t _garbage;
2368 public:
2369 ShenandoahCountGarbageClosure() : _garbage(0) {
2370 }
2371
2372 bool doHeapRegion(ShenandoahHeapRegion* r) {
2373 if (! r->is_humongous() && ! r->is_pinned() && ! r->in_collection_set()) {
2374 _garbage += r->garbage();
2375 }
2376 return false;
2377 }
2378
2379 size_t garbage() {
2380 return _garbage;
2381 }
2382 };
2383
2384 size_t ShenandoahHeap::garbage() {
2385 ShenandoahCountGarbageClosure cl;
2386 heap_region_iterate(&cl);
2387 return cl.garbage();
2388 }
2389
2390 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() {
2391 return _connection_matrix;
2392 }
2393
2394 ShenandoahPartialGC* ShenandoahHeap::partial_gc() {
2395 return _partial_gc;
2396 }
2397
2398 void ShenandoahHeap::do_partial_collection() {
2399 partial_gc()->do_partial_collection();
2400 }
2401
2402 template<class T>
2403 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2404 private:
2405 T cl;
2406 ShenandoahHeap* _heap;
2407 ShenandoahHeapRegionSet* _regions;
2408
2409 public:
2410 ShenandoahUpdateHeapRefsTask(ShenandoahHeapRegionSet* regions) :
2411 AbstractGangTask("Concurrent Update References Task"),
2412 cl(T()),
2413 _heap(ShenandoahHeap::heap()),
2414 _regions(regions) {
2415 }
2416
2417 void work(uint worker_id) {
2418 ShenandoahHeapRegion* r = _regions->claim_next();
2419 while (r != NULL) {
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 if (_heap->cancelled_concgc()) {
2431 return;
2432 }
2433 r = _regions->claim_next();
2434 }
2435 }
2436 };
2437
2438 void ShenandoahHeap::update_heap_references(ShenandoahHeapRegionSet* update_regions) {
2439 if (UseShenandoahMatrix) {
2440 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(update_regions);
2441 workers()->run_task(&task);
2442 } else {
2443 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(update_regions);
2444 workers()->run_task(&task);
2445 }
2446 }
2447
2448 void ShenandoahHeap::concurrent_update_heap_references() {
2449 _shenandoah_policy->record_phase_start(ShenandoahCollectorPolicy::conc_update_refs);
2450 ShenandoahHeapRegionSet* update_regions = regions();
2451 update_regions->clear_current_index();
2452 update_heap_references(update_regions);
2453 _shenandoah_policy->record_phase_end(ShenandoahCollectorPolicy::conc_update_refs);
2454 }
2455
2456 void ShenandoahHeap::prepare_update_refs() {
2457 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2458 set_evacuation_in_progress_at_safepoint(false);
2459 set_update_refs_in_progress(true);
2460 ensure_parsability(true);
2461 if (UseShenandoahMatrix) {
2462 connection_matrix()->clear_all();
2463 }
2464 for (uint i = 0; i < _num_regions; i++) {
2465 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2466 r->set_concurrent_iteration_safe_limit(r->top());
2467 }
2468 }
2469
2470 void ShenandoahHeap::finish_update_refs() {
2471 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2472
2473 if (cancelled_concgc()) {
2474 // Finish updating references where we left off.
2475 clear_cancelled_concgc();
2476 ShenandoahHeapRegionSet* update_regions = regions();
2477 update_heap_references(update_regions);
2478 }
2479
2480 assert(! cancelled_concgc(), "Should have been done right before");
2481 concurrentMark()->update_roots(ShenandoahCollectorPolicy::final_update_refs_roots);
2482 recycle_dirty_regions();
2483 set_need_update_refs(false);
2484
2485 if (ShenandoahVerify) {
2486 verify_update_refs();
2487 }
2488
2489 {
2490 // Rebuild the free set
2491 ShenandoahHeapLock hl(this);
2492 _free_regions->clear();
2493 size_t end = _ordered_regions->active_regions();
2494 for (size_t i = 0; i < end; i++) {
2495 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2496 if (!r->is_humongous()) {
2497 assert (!in_collection_set(r), "collection set should be clear");
2498 _free_regions->add_region(r);
2499 }
2500 }
2501 }
2502 set_update_refs_in_progress(false);
2503 }
2504
2505 class ShenandoahVerifyUpdateRefsClosure : public ExtendedOopClosure {
2506 private:
2507 template <class T>
2508 void do_oop_work(T* p) {
2509 T o = oopDesc::load_heap_oop(p);
2510 if (! oopDesc::is_null(o)) {
2511 oop obj = oopDesc::decode_heap_oop_not_null(o);
2512 guarantee(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
2513 "must not be forwarded");
2514 }
2515 }
2516 public:
2517 void do_oop(oop* p) { do_oop_work(p); }
2518 void do_oop(narrowOop* p) { do_oop_work(p); }
2519 };
2520
2521 void ShenandoahHeap::verify_update_refs() {
2522
2523 ensure_parsability(false);
2524
2525 ShenandoahVerifyUpdateRefsClosure cl;
2526
2527 // Verify roots.
2528 {
2529 CodeBlobToOopClosure blobsCl(&cl, false);
2530 CLDToOopClosure cldCl(&cl);
2531 ShenandoahRootProcessor rp(this, 1);
2532 rp.process_all_roots(&cl, &cl, &cldCl, &blobsCl, 0);
2533 }
2534
2535 // Verify heap.
2536 for (uint i = 0; i < num_regions(); i++) {
2537 ShenandoahHeapRegion* r = regions()->get(i);
2538 marked_object_oop_iterate(r, &cl);
2539 }
2540 }
2541
2542 #ifdef ASSERT
2543 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2544 assert(_heap_lock == locked, "must be locked");
2545 assert(_heap_lock_owner == Thread::current(), "must be owned by current thread");
2546 }
2547
2548 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2549 Thread* thr = Thread::current();
2550 assert((_heap_lock == locked && _heap_lock_owner == thr) ||
2551 (SafepointSynchronize::is_at_safepoint() && thr->is_VM_thread()),
2552 "must own heap lock or by VM thread at safepoint");
2553 }
2554
2555 #endif