1 /*
2 * Copyright (c) 2013, 2017, 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/shenandoahAllocTracker.hpp"
33 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentThread.hpp"
39 #include "gc/shenandoah/shenandoahFreeSet.hpp"
40 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
41 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
42 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
44 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
45 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
46 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
47 #include "gc/shenandoah/shenandoahPartialGC.hpp"
48 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
49 #include "gc/shenandoah/shenandoahStringDedup.hpp"
50 #include "gc/shenandoah/shenandoahUtils.hpp"
51 #include "gc/shenandoah/shenandoahVerifier.hpp"
52 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
53 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
54
55 #include "runtime/vmThread.hpp"
56 #include "services/mallocTracker.hpp"
57
58 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
59
60 #ifdef ASSERT
61 template <class T>
62 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
63 T o = oopDesc::load_heap_oop(p);
64 if (! oopDesc::is_null(o)) {
65 oop obj = oopDesc::decode_heap_oop_not_null(o);
66 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
67 "need to-space object here obj: "PTR_FORMAT" , rb(obj): "PTR_FORMAT", p: "PTR_FORMAT,
68 p2i(obj), p2i(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), p2i(p));
69 }
70 }
71
72 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
73 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
74 #endif
75
76 const char* ShenandoahHeap::name() const {
77 return "Shenandoah";
78 }
79
80 class ShenandoahPretouchTask : public AbstractGangTask {
81 private:
82 ShenandoahHeapRegionSet* _regions;
83 const size_t _bitmap_size;
84 const size_t _page_size;
85 char* _bitmap_base;
86 public:
87 ShenandoahPretouchTask(ShenandoahHeapRegionSet* regions,
88 char* bitmap_base, size_t bitmap_size,
89 size_t page_size) :
90 AbstractGangTask("Shenandoah PreTouch",
91 Universe::is_fully_initialized() ? GCId::current_raw() :
92 // During VM initialization there is
93 // no GC cycle that this task can be
94 // associated with.
95 GCId::undefined()),
96 _bitmap_base(bitmap_base),
97 _regions(regions),
98 _bitmap_size(bitmap_size),
99 _page_size(page_size) {
100 _regions->clear_current_index();
101 };
102
103 virtual void work(uint worker_id) {
104 ShenandoahHeapRegion* r = _regions->claim_next();
105 while (r != NULL) {
106 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
107 r->region_number(), p2i(r->bottom()), p2i(r->end()));
108 os::pretouch_memory(r->bottom(), r->end(), _page_size);
109
110 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
111 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
112 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
113
114 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
115 r->region_number(), p2i(_bitmap_base + start), p2i(_bitmap_base + end));
116 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
117
118 r = _regions->claim_next();
119 }
120 }
121 };
122
123 jint ShenandoahHeap::initialize() {
124 CollectedHeap::pre_initialize();
125
126 BrooksPointer::initial_checks();
127
128 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
129 size_t max_byte_size = collector_policy()->max_heap_byte_size();
130 size_t heap_alignment = collector_policy()->heap_alignment();
131
132 if (ShenandoahAlwaysPreTouch) {
133 // Enabled pre-touch means the entire heap is committed right away.
134 init_byte_size = max_byte_size;
135 }
136
137 Universe::check_alignment(max_byte_size,
138 ShenandoahHeapRegion::region_size_bytes(),
139 "shenandoah heap");
140 Universe::check_alignment(init_byte_size,
141 ShenandoahHeapRegion::region_size_bytes(),
142 "shenandoah heap");
143
144 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
145 heap_alignment);
146 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
147
148 set_barrier_set(new ShenandoahBarrierSet(this));
149 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
150
151 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
152 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
153 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
154 _committed = _initial_size;
155
156 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
157 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
158 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
159 }
160
161 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
162
163 _ordered_regions = new ShenandoahHeapRegionSet(_num_regions);
164 _free_regions = new ShenandoahFreeSet(_ordered_regions, _num_regions);
165
166 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
167
168 _top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
169 _top_at_mark_starts = _top_at_mark_starts_base -
170 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
171
172
173 {
174 ShenandoahHeapLocker locker(lock());
175 for (size_t i = 0; i < _num_regions; i++) {
176 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
177 (HeapWord*) pgc_rs.base() + reg_size_words * i,
178 reg_size_words,
179 i,
180 i < num_committed_regions);
181
182 _top_at_mark_starts_base[i] = r->bottom();
183
184 // Add to ordered regions first.
185 // We use the active size of ordered regions as the number of active regions in heap,
186 // free set and collection set use the number to assert the correctness of incoming regions.
187 _ordered_regions->add_region(r);
188 _free_regions->add_region(r);
189 assert(!collection_set()->is_in(i), "New region should not be in collection set");
190 }
191 }
192
193 assert(_ordered_regions->active_regions() == _num_regions, "Must match");
194 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
195 "misaligned heap: "PTR_FORMAT, p2i(base()));
196
197 LogTarget(Trace, gc, region) lt;
198 if (lt.is_enabled()) {
199 ResourceMark rm;
200 LogStream ls(lt);
201 log_trace(gc, region)("All Regions");
202 _ordered_regions->print_on(&ls);
203 log_trace(gc, region)("Free Regions");
204 _free_regions->print_on(&ls);
205 }
206
207 _recycled_regions = NEW_C_HEAP_ARRAY(size_t, _num_regions, mtGC);
208
209 // The call below uses stuff (the SATB* things) that are in G1, but probably
210 // belong into a shared location.
211 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
212 SATB_Q_FL_lock,
213 20 /*G1SATBProcessCompletedThreshold */,
214 Shared_SATB_Q_lock);
215
216 // Reserve space for prev and next bitmap.
217 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
218 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
219
220 size_t bitmap_bytes_per_region = _bitmap_size / _num_regions;
221 _bitmap_words_per_region = bitmap_bytes_per_region / HeapWordSize;
222
223 guarantee(is_power_of_2(bitmap_bytes_per_region),
224 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
225 guarantee((bitmap_bytes_per_region % os::vm_page_size()) == 0,
226 "Bitmap bytes per region should be page-granular: bpr = " SIZE_FORMAT ", page size = %d",
227 bitmap_bytes_per_region, os::vm_page_size());
228 guarantee(is_power_of_2(_bitmap_words_per_region),
229 "Bitmap words per region Should be power of two: " SIZE_FORMAT, _bitmap_words_per_region);
230 guarantee(bitmap_bytes_per_region >= (size_t)os::vm_page_size(),
231 "Bitmap slice per region (" SIZE_FORMAT ") should be larger than page size (%d)",
232 bitmap_bytes_per_region, os::vm_page_size());
233
234 size_t bitmap_page_size = UseLargePages && (bitmap_bytes_per_region >= (size_t)os::large_page_size()) ?
235 (size_t)os::large_page_size() : (size_t)os::vm_page_size();
236
237 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
238 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
239 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
240
241 {
242 ShenandoahHeapLocker locker(lock());
243 for (size_t i = 0; i < _num_regions; i++) {
244 ShenandoahHeapRegion* r = _ordered_regions->get(i);
245 if (r->is_committed()) {
246 commit_bitmaps(r);
247 }
248 }
249 }
250
251 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
252
253 if (ShenandoahVerify) {
254 ReservedSpace verify_bitmap(_bitmap_size, page_size);
255 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
256 "couldn't allocate verification bitmap");
257 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
258 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
259 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
260 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
261 }
262
263 if (ShenandoahAlwaysPreTouch) {
264 assert (!AlwaysPreTouch, "Should have been overridden");
265
266 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
267 // before initialize() below zeroes it with initializing thread. For any given region,
268 // we touch the region and the corresponding bitmaps from the same thread.
269
270 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
271 _ordered_regions->count(), page_size);
272 ShenandoahPretouchTask cl(_ordered_regions, bitmap.base(), _bitmap_size, page_size);
273 _workers->run_task(&cl);
274 }
275
276 __mark_bit_map.initialize(_heap_region, _bitmap_region);
277 _mark_bit_map = & __mark_bit_map;
278
279 if (UseShenandoahMatrix) {
280 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
281 } else {
282 _connection_matrix = NULL;
283 }
284
285 _partial_gc = _shenandoah_policy->can_do_partial_gc() ?
286 new ShenandoahPartialGC(this, _num_regions) :
287 NULL;
288
289 _monitoring_support = new ShenandoahMonitoringSupport(this);
290
291 _phase_timings = new ShenandoahPhaseTimings();
292
293 if (ShenandoahAllocationTrace) {
294 _alloc_tracker = new ShenandoahAllocTracker();
295 }
296
297 ShenandoahStringDedup::initialize();
298
299 _concurrent_gc_thread = new ShenandoahConcurrentThread();
300
301 ShenandoahMarkCompact::initialize();
302
303 ShenandoahCodeRoots::initialize();
304
305 return JNI_OK;
306 }
307
308 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
309 CollectedHeap(),
310 _shenandoah_policy(policy),
311 _concurrent_mark_in_progress(0),
312 _evacuation_in_progress(0),
313 _full_gc_in_progress(false),
314 _update_refs_in_progress(false),
315 _free_regions(NULL),
316 _collection_set(NULL),
317 _bytes_allocated_since_cm(0),
318 _bytes_allocated_during_cm(0),
319 _allocated_last_gc(0),
320 _used_start_gc(0),
321 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
322 _ref_processor(NULL),
323 _top_at_mark_starts(NULL),
324 _top_at_mark_starts_base(NULL),
325 __mark_bit_map(),
326 _mark_bit_map(NULL),
327 _connection_matrix(NULL),
328 _cancelled_concgc(0),
329 _need_update_refs(false),
330 _need_reset_bitmap(false),
331 _bitmap_valid(true),
332 _verifier(NULL),
333 _heap_lock(0),
334 _used_at_last_gc(0),
335 _alloc_seq_at_last_gc_start(0),
336 _alloc_seq_at_last_gc_end(0),
337 _safepoint_workers(NULL),
338 #ifdef ASSERT
339 _heap_lock_owner(NULL),
340 _heap_expansion_count(0),
341 #endif
342 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
343 _phase_timings(NULL),
344 _alloc_tracker(NULL)
345 {
346 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
347 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
348 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
349
350 _scm = new ShenandoahConcurrentMark();
351 _used = 0;
352
353 _max_workers = MAX2(_max_workers, 1U);
354 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
355 /* are_GC_task_threads */true,
356 /* are_ConcurrentGC_threads */false);
357 if (_workers == NULL) {
358 vm_exit_during_initialization("Failed necessary allocation.");
359 } else {
360 _workers->initialize_workers();
361 }
362
363 if (ParallelSafepointCleanupThreads > 1) {
364 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
365 ParallelSafepointCleanupThreads,
366 false, false);
367 _safepoint_workers->initialize_workers();
368 }
369 }
370
371 class ShenandoahResetBitmapTask : public AbstractGangTask {
372 private:
373 ShenandoahHeapRegionSet* _regions;
374
375 public:
376 ShenandoahResetBitmapTask(ShenandoahHeapRegionSet* regions) :
377 AbstractGangTask("Parallel Reset Bitmap Task"),
378 _regions(regions) {
379 _regions->clear_current_index();
380 }
381
382 void work(uint worker_id) {
383 ShenandoahHeapRegion* region = _regions->claim_next();
384 ShenandoahHeap* heap = ShenandoahHeap::heap();
385 while (region != NULL) {
386 if (region->is_committed()) {
387 HeapWord* bottom = region->bottom();
388 HeapWord* top = heap->top_at_mark_start(region->bottom());
389 if (top > bottom) {
390 heap->mark_bit_map()->clear_range_large(MemRegion(bottom, top));
391 }
392 assert(heap->is_bitmap_clear_range(bottom, region->end()), "must be clear");
393 }
394 region = _regions->claim_next();
395 }
396 }
397 };
398
399 void ShenandoahHeap::reset_mark_bitmap(WorkGang* workers) {
400 assert_gc_workers(workers->active_workers());
401
402 ShenandoahResetBitmapTask task = ShenandoahResetBitmapTask(_ordered_regions);
403 workers->run_task(&task);
404 }
405
406 bool ShenandoahHeap::is_bitmap_clear() {
407 for (size_t idx = 0; idx < _num_regions; idx++) {
408 ShenandoahHeapRegion* r = _ordered_regions->get(idx);
409 if (r->is_committed() && !is_bitmap_clear_range(r->bottom(), r->end())) {
410 return false;
411 }
412 }
413 return true;
414 }
415
416 bool ShenandoahHeap::is_bitmap_clear_range(HeapWord* start, HeapWord* end) {
417 return _mark_bit_map->getNextMarkedWordAddress(start, end) == end;
418 }
419
420 void ShenandoahHeap::print_on(outputStream* st) const {
421 st->print_cr("Shenandoah Heap");
422 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
423 capacity() / K, committed() / K, used() / K);
424 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
425 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
426
427 st->print("Status: ");
428 if (concurrent_mark_in_progress()) {
429 st->print("marking ");
430 } else if (is_evacuation_in_progress()) {
431 st->print("evacuating ");
432 } else if (is_update_refs_in_progress()) {
433 st->print("updating refs ");
434 } else {
435 st->print("idle ");
436 }
437 if (cancelled_concgc()) {
438 st->print("cancelled ");
439 }
440 st->cr();
441
442 st->print_cr("Reserved region:");
443 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
444 p2i(reserved_region().start()),
445 p2i(reserved_region().end()));
446
447 if (UseShenandoahMatrix) {
448 st->print_cr("Matrix:");
449
450 ShenandoahConnectionMatrix* matrix = connection_matrix();
451 if (matrix != NULL) {
452 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
453 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
454 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
455 } else {
456 st->print_cr(" No matrix.");
457 }
458 }
459
460 if (Verbose) {
461 print_heap_regions_on(st);
462 }
463 }
464
465 class ShenandoahInitGCLABClosure : public ThreadClosure {
466 public:
467 void do_thread(Thread* thread) {
468 thread->gclab().initialize(true);
469 }
470 };
471
472 void ShenandoahHeap::post_initialize() {
473 if (UseTLAB) {
474 MutexLocker ml(Threads_lock);
475
476 ShenandoahInitGCLABClosure init_gclabs;
477 Threads::java_threads_do(&init_gclabs);
478 gc_threads_do(&init_gclabs);
479
480 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
481 // Now, we will let WorkGang to initialize gclab when new worker is created.
482 _workers->set_initialize_gclab();
483 }
484
485 _scm->initialize(_max_workers);
486
487 ref_processing_init();
488
489 _shenandoah_policy->post_heap_initialize();
490 }
491
492 size_t ShenandoahHeap::used() const {
493 OrderAccess::acquire();
494 return _used;
495 }
496
497 size_t ShenandoahHeap::committed() const {
498 OrderAccess::acquire();
499 return _committed;
500 }
501
502 void ShenandoahHeap::increase_committed(size_t bytes) {
503 assert_heaplock_or_safepoint();
504 _committed += bytes;
505 }
506
507 void ShenandoahHeap::decrease_committed(size_t bytes) {
508 assert_heaplock_or_safepoint();
509 _committed -= bytes;
510 }
511
512 void ShenandoahHeap::increase_used(size_t bytes) {
513 assert_heaplock_or_safepoint();
514 _used += bytes;
515 }
516
517 void ShenandoahHeap::set_used(size_t bytes) {
518 assert_heaplock_or_safepoint();
519 _used = bytes;
520 }
521
522 void ShenandoahHeap::decrease_used(size_t bytes) {
523 assert_heaplock_or_safepoint();
524 assert(_used >= bytes, "never decrease heap size by more than we've left");
525 _used -= bytes;
526 }
527
528 size_t ShenandoahHeap::capacity() const {
529 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
530 }
531
532 bool ShenandoahHeap::is_maximal_no_gc() const {
533 Unimplemented();
534 return true;
535 }
536
537 size_t ShenandoahHeap::max_capacity() const {
538 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
539 }
540
541 size_t ShenandoahHeap::initial_capacity() const {
542 return _initial_size;
543 }
544
545 bool ShenandoahHeap::is_in(const void* p) const {
546 HeapWord* heap_base = (HeapWord*) base();
547 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
548 return p >= heap_base && p < last_region_end;
549 }
550
551 bool ShenandoahHeap::is_scavengable(const void* p) {
552 return true;
553 }
554
555 void ShenandoahHeap::handle_heap_shrinkage() {
556 ShenandoahHeapLocker locker(lock());
557
558 ShenandoahHeapRegionSet* set = regions();
559
560 size_t count = 0;
561 double current = os::elapsedTime();
562 for (size_t i = 0; i < num_regions(); i++) {
563 ShenandoahHeapRegion* r = set->get(i);
564 if (r->is_empty_committed() &&
565 (current - r->empty_time()) * 1000 > ShenandoahUncommitDelay &&
566 r->make_empty_uncommitted()) {
567 count++;
568 }
569 }
570
571 if (count > 0) {
572 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
573 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
574 }
575 }
576
577 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
578 // Retain tlab and allocate object in shared space if
579 // the amount free in the tlab is too large to discard.
580 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
581 thread->gclab().record_slow_allocation(size);
582 return NULL;
583 }
584
585 // Discard gclab and allocate a new one.
586 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
587 size_t new_gclab_size = thread->gclab().compute_size(size);
588
589 thread->gclab().clear_before_allocation();
590
591 if (new_gclab_size == 0) {
592 return NULL;
593 }
594
595 // Allocate a new GCLAB...
596 HeapWord* obj = allocate_new_gclab(new_gclab_size);
597 if (obj == NULL) {
598 return NULL;
599 }
600
601 if (ZeroTLAB) {
602 // ..and clear it.
603 Copy::zero_to_words(obj, new_gclab_size);
604 } else {
605 // ...and zap just allocated object.
606 #ifdef ASSERT
607 // Skip mangling the space corresponding to the object header to
608 // ensure that the returned space is not considered parsable by
609 // any concurrent GC thread.
610 size_t hdr_size = oopDesc::header_size();
611 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
612 #endif // ASSERT
613 }
614 thread->gclab().fill(obj, obj + size, new_gclab_size);
615 return obj;
616 }
617
618 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
619 #ifdef ASSERT
620 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
621 #endif
622 return allocate_new_lab(word_size, _alloc_tlab);
623 }
624
625 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
626 #ifdef ASSERT
627 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
628 #endif
629 return allocate_new_lab(word_size, _alloc_gclab);
630 }
631
632 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
633 HeapWord* result = allocate_memory(word_size, type);
634
635 if (result != NULL) {
636 assert(! in_collection_set(result), "Never allocate in collection set");
637 _bytes_allocated_since_cm += word_size * HeapWordSize;
638
639 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
640
641 }
642 return result;
643 }
644
645 ShenandoahHeap* ShenandoahHeap::heap() {
646 CollectedHeap* heap = Universe::heap();
647 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
648 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
649 return (ShenandoahHeap*) heap;
650 }
651
652 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
653 CollectedHeap* heap = Universe::heap();
654 return (ShenandoahHeap*) heap;
655 }
656
657 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
658 ShenandoahAllocTrace trace_alloc(word_size, type);
659
660 bool in_new_region = false;
661 HeapWord* result = allocate_memory_under_lock(word_size, type, in_new_region);
662
663 if (type == _alloc_tlab || type == _alloc_shared) {
664 // Allocation failed, try full-GC, then retry allocation.
665 //
666 // It might happen that one of the threads requesting allocation would unblock
667 // way later after full-GC happened, only to fail the second allocation, because
668 // other threads have already depleted the free storage. In this case, a better
669 // strategy would be to try full-GC again.
670 //
671 // Lacking the way to detect progress from "collect" call, we are left with blindly
672 // retrying for some bounded number of times.
673 // TODO: Poll if Full GC made enough progress to warrant retry.
674 int tries = 0;
675 while ((result == NULL) && (tries++ < ShenandoahFullGCTries)) {
676 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing full GC, try %d",
677 p2i(Thread::current()), word_size * HeapWordSize, tries);
678 collect(GCCause::_allocation_failure);
679 result = allocate_memory_under_lock(word_size, type, in_new_region);
680 }
681 }
682
683 if (in_new_region) {
684 // Update monitoring counters when we took a new region. This amortizes the
685 // update costs on slow path.
686 concurrent_thread()->trigger_counters_update();
687 }
688
689 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
690 word_size, p2i(result), Thread::current()->osthread()->thread_id());
691
692 return result;
693 }
694
695 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
696 ShenandoahHeapLocker locker(lock());
697 return _free_regions->allocate(word_size, type, in_new_region);
698 }
699
700 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
701 bool* gc_overhead_limit_was_exceeded) {
702 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
703 HeapWord* result = filler + BrooksPointer::word_size();
704 if (filler != NULL) {
705 BrooksPointer::initialize(oop(result));
706 _bytes_allocated_since_cm += size * HeapWordSize;
707
708 assert(! in_collection_set(result), "never allocate in targetted region");
709 return result;
710 } else {
711 return NULL;
712 }
713 }
714
715 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
716 private:
717 ShenandoahHeap* _heap;
718 Thread* _thread;
719 public:
720 ShenandoahEvacuateUpdateRootsClosure() :
721 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
722 }
723
724 private:
725 template <class T>
726 void do_oop_work(T* p) {
727 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
728
729 T o = oopDesc::load_heap_oop(p);
730 if (! oopDesc::is_null(o)) {
731 oop obj = oopDesc::decode_heap_oop_not_null(o);
732 if (_heap->in_collection_set(obj)) {
733 assert(_heap->is_marked(obj), "only evacuate marked objects %d %d",
734 _heap->is_marked(obj), _heap->is_marked(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)));
735 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
736 if (oopDesc::unsafe_equals(resolved, obj)) {
737 bool evac;
738 resolved = _heap->evacuate_object(obj, _thread, evac);
739 }
740 oopDesc::encode_store_heap_oop(p, resolved);
741 }
742 }
743 }
744
745 public:
746 void do_oop(oop* p) {
747 do_oop_work(p);
748 }
749 void do_oop(narrowOop* p) {
750 do_oop_work(p);
751 }
752 };
753
754 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
755 private:
756 ShenandoahHeap* _heap;
757 Thread* _thread;
758 public:
759 ShenandoahEvacuateRootsClosure() :
760 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
761 }
762
763 private:
764 template <class T>
765 void do_oop_work(T* p) {
766 T o = oopDesc::load_heap_oop(p);
767 if (! oopDesc::is_null(o)) {
768 oop obj = oopDesc::decode_heap_oop_not_null(o);
769 if (_heap->in_collection_set(obj)) {
770 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
771 if (oopDesc::unsafe_equals(resolved, obj)) {
772 bool evac;
773 _heap->evacuate_object(obj, _thread, evac);
774 }
775 }
776 }
777 }
778
779 public:
780 void do_oop(oop* p) {
781 do_oop_work(p);
782 }
783 void do_oop(narrowOop* p) {
784 do_oop_work(p);
785 }
786 };
787
788 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
789 private:
790 ShenandoahHeap* const _heap;
791 Thread* const _thread;
792 public:
793 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
794 _heap(heap), _thread(Thread::current()) {}
795
796 void do_object(oop p) {
797 assert(_heap->is_marked(p), "expect only marked objects");
798 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p))) {
799 bool evac;
800 _heap->evacuate_object(p, _thread, evac);
801 }
802 }
803 };
804
805 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
806 private:
807 ShenandoahHeap* const _sh;
808 ShenandoahCollectionSet* const _cs;
809 volatile jbyte _claimed_codecache;
810
811 bool claim_codecache() {
812 jbyte old = Atomic::cmpxchg((jbyte)1, &_claimed_codecache, (jbyte)0);
813 return old == 0;
814 }
815 public:
816 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
817 ShenandoahCollectionSet* cs) :
818 AbstractGangTask("Parallel Evacuation Task"),
819 _cs(cs),
820 _sh(sh),
821 _claimed_codecache(0)
822 {}
823
824 void work(uint worker_id) {
825
826 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
827
828 // If concurrent code cache evac is enabled, evacuate it here.
829 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
830 // nmethods. The update would be handled elsewhere.
831 if (ShenandoahConcurrentEvacCodeRoots && claim_codecache()) {
832 ShenandoahEvacuateRootsClosure cl;
833 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
834 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
835 CodeCache::blobs_do(&blobs);
836 }
837
838 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
839 ShenandoahHeapRegion* r;
840 while ((r =_cs->claim_next()) != NULL) {
841 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
842 worker_id,
843 r->region_number());
844
845 assert(r->has_live(), "all-garbage regions are reclaimed early");
846 _sh->marked_object_iterate(r, &cl);
847
848 if (_sh->check_cancelled_concgc_and_yield()) {
849 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
850 break;
851 }
852 }
853 }
854 };
855
856 void ShenandoahHeap::trash_cset_regions() {
857 ShenandoahHeapLocker locker(lock());
858
859 ShenandoahCollectionSet* set = collection_set();
860 ShenandoahHeapRegion* r;
861 set->clear_current_index();
862 while ((r = set->next()) != NULL) {
863 r->make_trash();
864 }
865 collection_set()->clear();
866 }
867
868 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
869 st->print_cr("Heap Regions:");
870 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
871 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
872 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
873 st->print_cr("FTS=first use timestamp, LTS=last use timestamp");
874
875 _ordered_regions->print_on(st);
876 }
877
878 size_t ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
879 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
880
881 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
882 size_t size = humongous_obj->size() + BrooksPointer::word_size();
883 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
884 size_t index = start->region_number() + required_regions - 1;
885
886 assert(!start->has_live(), "liveness must be zero");
887 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
888
889 for(size_t i = 0; i < required_regions; i++) {
890 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
891 // as it expects that every region belongs to a humongous region starting with a humongous start region.
892 ShenandoahHeapRegion* region = _ordered_regions->get(index --);
893
894 LogTarget(Trace, gc, humongous) lt;
895 if (lt.is_enabled()) {
896 ResourceMark rm;
897 LogStream ls(lt);
898 region->print_on(&ls);
899 }
900
901 assert(region->is_humongous(), "expect correct humongous start or continuation");
902 assert(!in_collection_set(region), "Humongous region should not be in collection set");
903
904 region->make_trash();
905 }
906 return required_regions;
907 }
908
909 #ifdef ASSERT
910 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
911 bool heap_region_do(ShenandoahHeapRegion* r) {
912 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
913 return false;
914 }
915 };
916 #endif
917
918 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
919 assert(_ordered_regions->get(0)->region_number() == 0, "FIXME CHF. FIXME CHF!");
920
921 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
922
923 if (!cancelled_concgc()) {
924 // Allocations might have happened before we STWed here, record peak:
925 shenandoahPolicy()->record_peak_occupancy();
926
927 ensure_parsability(true);
928
929 if (ShenandoahVerify) {
930 verifier()->verify_after_concmark();
931 }
932
933 trash_cset_regions();
934
935 // NOTE: This needs to be done during a stop the world pause, because
936 // putting regions into the collection set concurrently with Java threads
937 // will create a race. In particular, acmp could fail because when we
938 // resolve the first operand, the containing region might not yet be in
939 // the collection set, and thus return the original oop. When the 2nd
940 // operand gets resolved, the region could be in the collection set
941 // and the oop gets evacuated. If both operands have originally been
942 // the same, we get false negatives.
943
944 {
945 ShenandoahHeapLocker locker(lock());
946 _collection_set->clear();
947 _free_regions->clear();
948
949 #ifdef ASSERT
950 ShenandoahCheckCollectionSetClosure ccsc;
951 _ordered_regions->heap_region_iterate(&ccsc);
952 #endif
953
954 _shenandoah_policy->choose_collection_set(_collection_set);
955
956 _shenandoah_policy->choose_free_set(_free_regions);
957 }
958
959 _bytes_allocated_since_cm = 0;
960
961 Universe::update_heap_info_at_gc();
962
963 if (ShenandoahVerify) {
964 verifier()->verify_before_evacuation();
965 }
966 }
967 }
968
969
970 class ShenandoahRetireTLABClosure : public ThreadClosure {
971 private:
972 bool _retire;
973
974 public:
975 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
976
977 void do_thread(Thread* thread) {
978 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
979 thread->gclab().make_parsable(_retire);
980 }
981 };
982
983 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
984 if (UseTLAB) {
985 CollectedHeap::ensure_parsability(retire_tlabs);
986 ShenandoahRetireTLABClosure cl(retire_tlabs);
987 Threads::java_threads_do(&cl);
988 gc_threads_do(&cl);
989 }
990 }
991
992
993 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
994 ShenandoahRootEvacuator* _rp;
995 public:
996
997 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
998 AbstractGangTask("Shenandoah evacuate and update roots"),
999 _rp(rp)
1000 {
1001 // Nothing else to do.
1002 }
1003
1004 void work(uint worker_id) {
1005 ShenandoahEvacuateUpdateRootsClosure cl;
1006
1007 if (ShenandoahConcurrentEvacCodeRoots) {
1008 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1009 } else {
1010 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1011 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1012 }
1013 }
1014 };
1015
1016 class ShenandoahFixRootsTask : public AbstractGangTask {
1017 ShenandoahRootEvacuator* _rp;
1018 public:
1019
1020 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1021 AbstractGangTask("Shenandoah update roots"),
1022 _rp(rp)
1023 {
1024 // Nothing else to do.
1025 }
1026
1027 void work(uint worker_id) {
1028 ShenandoahUpdateRefsClosure cl;
1029 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1030
1031 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1032 }
1033 };
1034
1035 void ShenandoahHeap::evacuate_and_update_roots() {
1036
1037 #if defined(COMPILER2) || INCLUDE_JVMCI
1038 DerivedPointerTable::clear();
1039 #endif
1040 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1041
1042 {
1043 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1044 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1045 workers()->run_task(&roots_task);
1046 }
1047
1048 #if defined(COMPILER2) || INCLUDE_JVMCI
1049 DerivedPointerTable::update_pointers();
1050 #endif
1051 if (cancelled_concgc()) {
1052 fixup_roots();
1053 }
1054 }
1055
1056
1057 void ShenandoahHeap::fixup_roots() {
1058 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1059
1060 // If initial evacuation has been cancelled, we need to update all references
1061 // after all workers have finished. Otherwise we might run into the following problem:
1062 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1063 // GC thread 2 evacuates the same object X to to-space
1064 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1065 // clear() and update_pointers() must always be called in pairs,
1066 // cannot nest with above clear()/update_pointers().
1067 #if defined(COMPILER2) || INCLUDE_JVMCI
1068 DerivedPointerTable::clear();
1069 #endif
1070 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1071 ShenandoahFixRootsTask update_roots_task(&rp);
1072 workers()->run_task(&update_roots_task);
1073 #if defined(COMPILER2) || INCLUDE_JVMCI
1074 DerivedPointerTable::update_pointers();
1075 #endif
1076 }
1077
1078 void ShenandoahHeap::do_evacuation() {
1079 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
1080
1081 LogTarget(Trace, gc, region) lt_region;
1082 LogTarget(Trace, gc, cset) lt_cset;
1083
1084 if (lt_region.is_enabled()) {
1085 ResourceMark rm;
1086 LogStream ls(lt_region);
1087 ls.print_cr("All available regions:");
1088 print_heap_regions_on(&ls);
1089 }
1090
1091 if (lt_cset.is_enabled()) {
1092 ResourceMark rm;
1093 LogStream ls(lt_cset);
1094 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1095 _collection_set->print_on(&ls);
1096
1097 ls.print_cr("Free set:");
1098 _free_regions->print_on(&ls);
1099 }
1100
1101 ShenandoahParallelEvacuationTask task(this, _collection_set);
1102 workers()->run_task(&task);
1103
1104 if (lt_cset.is_enabled()) {
1105 ResourceMark rm;
1106 LogStream ls(lt_cset);
1107 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1108 _collection_set->count());
1109 _collection_set->print_on(&ls);
1110
1111 ls.print_cr("After evacuation free set:");
1112 _free_regions->print_on(&ls);
1113 }
1114
1115 if (lt_region.is_enabled()) {
1116 ResourceMark rm;
1117 LogStream ls(lt_region);
1118 ls.print_cr("All regions after evacuation:");
1119 print_heap_regions_on(&ls);
1120 }
1121 }
1122
1123 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1124 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1125
1126 CodeBlobToOopClosure blobsCl(cl, false);
1127 CLDToOopClosure cldCl(cl);
1128
1129 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1130 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, 0);
1131 }
1132
1133 bool ShenandoahHeap::supports_tlab_allocation() const {
1134 return true;
1135 }
1136
1137 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1138 return MIN2(_free_regions->unsafe_peek_free(), max_tlab_size());
1139 }
1140
1141 size_t ShenandoahHeap::max_tlab_size() const {
1142 return ShenandoahHeapRegion::max_tlab_size_bytes();
1143 }
1144
1145 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1146 public:
1147 void do_thread(Thread* thread) {
1148 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1149 thread->gclab().resize();
1150 }
1151 };
1152
1153 void ShenandoahHeap::resize_all_tlabs() {
1154 CollectedHeap::resize_all_tlabs();
1155
1156 ShenandoahResizeGCLABClosure cl;
1157 Threads::java_threads_do(&cl);
1158 gc_threads_do(&cl);
1159 }
1160
1161 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1162 public:
1163 void do_thread(Thread* thread) {
1164 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1165 thread->gclab().accumulate_statistics();
1166 thread->gclab().initialize_statistics();
1167 }
1168 };
1169
1170 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1171 ShenandoahAccumulateStatisticsGCLABClosure cl;
1172 Threads::java_threads_do(&cl);
1173 gc_threads_do(&cl);
1174 }
1175
1176 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1177 return true;
1178 }
1179
1180 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1181 // Overridden to do nothing.
1182 return new_obj;
1183 }
1184
1185 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1186 return true;
1187 }
1188
1189 bool ShenandoahHeap::card_mark_must_follow_store() const {
1190 return false;
1191 }
1192
1193 void ShenandoahHeap::collect(GCCause::Cause cause) {
1194 assert(cause != GCCause::_gc_locker, "no JNI critical callback");
1195 if (GCCause::is_user_requested_gc(cause)) {
1196 if (!DisableExplicitGC) {
1197 if (ExplicitGCInvokesConcurrent) {
1198 _concurrent_gc_thread->do_conc_gc();
1199 } else {
1200 _concurrent_gc_thread->do_full_gc(cause);
1201 }
1202 }
1203 } else if (cause == GCCause::_allocation_failure) {
1204 collector_policy()->set_should_clear_all_soft_refs(true);
1205 _concurrent_gc_thread->do_full_gc(cause);
1206 }
1207 }
1208
1209 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1210 //assert(false, "Shouldn't need to do full collections");
1211 }
1212
1213 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1214 Unimplemented();
1215 return NULL;
1216
1217 }
1218
1219 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1220 return _shenandoah_policy;
1221 }
1222
1223
1224 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1225 Space* sp = heap_region_containing(addr);
1226 if (sp != NULL) {
1227 return sp->block_start(addr);
1228 }
1229 return NULL;
1230 }
1231
1232 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1233 Space* sp = heap_region_containing(addr);
1234 assert(sp != NULL, "block_size of address outside of heap");
1235 return sp->block_size(addr);
1236 }
1237
1238 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1239 Space* sp = heap_region_containing(addr);
1240 return sp->block_is_obj(addr);
1241 }
1242
1243 jlong ShenandoahHeap::millis_since_last_gc() {
1244 return 0;
1245 }
1246
1247 void ShenandoahHeap::prepare_for_verify() {
1248 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1249 ensure_parsability(false);
1250 }
1251 }
1252
1253 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1254 workers()->print_worker_threads_on(st);
1255 }
1256
1257 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1258 workers()->threads_do(tcl);
1259 }
1260
1261 void ShenandoahHeap::print_tracing_info() const {
1262 LogTarget(Info, gc, stats) lt;
1263 if (lt.is_enabled()) {
1264 ResourceMark rm;
1265 LogStream ls(lt);
1266
1267 phase_timings()->print_on(&ls);
1268
1269 ls.cr();
1270 ls.cr();
1271
1272 shenandoahPolicy()->print_gc_stats(&ls);
1273
1274 ls.cr();
1275 ls.cr();
1276
1277 if (ShenandoahAllocationTrace) {
1278 assert(alloc_tracker() != NULL, "Must be");
1279 alloc_tracker()->print_on(&ls);
1280 } else {
1281 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1282 }
1283 }
1284 }
1285
1286 void ShenandoahHeap::verify(VerifyOption vo) {
1287 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1288 if (ShenandoahVerify) {
1289 verifier()->verify_generic(vo);
1290 } else {
1291 // TODO: Consider allocating verification bitmaps on demand,
1292 // and turn this on unconditionally.
1293 }
1294 }
1295 }
1296 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1297 return _free_regions->capacity();
1298 }
1299
1300 class ShenandoahIterateObjectClosureRegionClosure: public ShenandoahHeapRegionClosure {
1301 ObjectClosure* _cl;
1302 public:
1303 ShenandoahIterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
1304 bool heap_region_do(ShenandoahHeapRegion* r) {
1305 ShenandoahHeap::heap()->marked_object_iterate(r, _cl);
1306 return false;
1307 }
1308 };
1309
1310 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1311 ShenandoahIterateObjectClosureRegionClosure blk(cl);
1312 heap_region_iterate(&blk, false, true);
1313 }
1314
1315 class ShenandoahSafeObjectIterateAdjustPtrsClosure : public MetadataAwareOopClosure {
1316 private:
1317 ShenandoahHeap* _heap;
1318
1319 public:
1320 ShenandoahSafeObjectIterateAdjustPtrsClosure() : _heap(ShenandoahHeap::heap()) {}
1321
1322 private:
1323 template <class T>
1324 inline void do_oop_work(T* p) {
1325 T o = oopDesc::load_heap_oop(p);
1326 if (!oopDesc::is_null(o)) {
1327 oop obj = oopDesc::decode_heap_oop_not_null(o);
1328 oopDesc::encode_store_heap_oop(p, BrooksPointer::forwardee(obj));
1329 }
1330 }
1331 public:
1332 void do_oop(oop* p) {
1333 do_oop_work(p);
1334 }
1335 void do_oop(narrowOop* p) {
1336 do_oop_work(p);
1337 }
1338 };
1339
1340 class ShenandoahSafeObjectIterateAndUpdate : public ObjectClosure {
1341 private:
1342 ObjectClosure* _cl;
1343 public:
1344 ShenandoahSafeObjectIterateAndUpdate(ObjectClosure *cl) : _cl(cl) {}
1345
1346 virtual void do_object(oop obj) {
1347 assert (oopDesc::unsafe_equals(obj, BrooksPointer::forwardee(obj)),
1348 "avoid double-counting: only non-forwarded objects here");
1349
1350 // Fix up the ptrs.
1351 ShenandoahSafeObjectIterateAdjustPtrsClosure adjust_ptrs;
1352 obj->oop_iterate(&adjust_ptrs);
1353
1354 // Can reply the object now:
1355 _cl->do_object(obj);
1356 }
1357 };
1358
1359 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1360 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1361
1362 // Safe iteration does objects only with correct references.
1363 // This is why we skip collection set regions that have stale copies of objects,
1364 // and fix up the pointers in the returned objects.
1365
1366 ShenandoahSafeObjectIterateAndUpdate safe_cl(cl);
1367 ShenandoahIterateObjectClosureRegionClosure blk(&safe_cl);
1368 heap_region_iterate(&blk,
1369 /* skip_cset_regions = */ true,
1370 /* skip_humongous_continuations = */ true);
1371
1372 _need_update_refs = false; // already updated the references
1373 }
1374
1375 // Apply blk->heap_region_do() on all committed regions in address order,
1376 // terminating the iteration early if heap_region_do() returns true.
1377 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1378 for (size_t i = 0; i < num_regions(); i++) {
1379 ShenandoahHeapRegion* current = _ordered_regions->get(i);
1380 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1381 continue;
1382 }
1383 if (skip_cset_regions && in_collection_set(current)) {
1384 continue;
1385 }
1386 if (blk->heap_region_do(current)) {
1387 return;
1388 }
1389 }
1390 }
1391
1392 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1393 private:
1394 ShenandoahHeap* sh;
1395 public:
1396 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1397
1398 bool heap_region_do(ShenandoahHeapRegion* r) {
1399 r->clear_live_data();
1400 sh->set_top_at_mark_start(r->bottom(), r->top());
1401 return false;
1402 }
1403 };
1404
1405 void ShenandoahHeap::start_concurrent_marking() {
1406 if (ShenandoahVerify) {
1407 verifier()->verify_before_concmark();
1408 }
1409
1410 {
1411 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1412 accumulate_statistics_all_tlabs();
1413 }
1414
1415 set_concurrent_mark_in_progress(true);
1416 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1417 if (UseTLAB) {
1418 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1419 ensure_parsability(true);
1420 }
1421
1422 _shenandoah_policy->record_bytes_allocated(_bytes_allocated_since_cm);
1423 _used_start_gc = used();
1424
1425 {
1426 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1427 ShenandoahClearLivenessClosure clc(this);
1428 heap_region_iterate(&clc);
1429 }
1430
1431 // Make above changes visible to worker threads
1432 OrderAccess::fence();
1433
1434 concurrentMark()->init_mark_roots();
1435
1436 if (UseTLAB) {
1437 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1438 resize_all_tlabs();
1439 }
1440 }
1441
1442 void ShenandoahHeap::stop_concurrent_marking() {
1443 assert(concurrent_mark_in_progress(), "How else could we get here?");
1444 if (! cancelled_concgc()) {
1445 // If we needed to update refs, and concurrent marking has been cancelled,
1446 // we need to finish updating references.
1447 set_need_update_refs(false);
1448 }
1449 set_concurrent_mark_in_progress(false);
1450
1451 LogTarget(Trace, gc, region) lt;
1452 if (lt.is_enabled()) {
1453 ResourceMark rm;
1454 LogStream ls(lt);
1455 ls.print_cr("Regions at stopping the concurrent mark:");
1456 print_heap_regions_on(&ls);
1457 }
1458 }
1459
1460 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1461 _concurrent_mark_in_progress = in_progress ? 1 : 0;
1462 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1463 }
1464
1465 void ShenandoahHeap::set_evacuation_in_progress_concurrently(bool in_progress) {
1466 // Note: it is important to first release the _evacuation_in_progress flag here,
1467 // so that Java threads can get out of oom_during_evacuation() and reach a safepoint,
1468 // in case a VM task is pending.
1469 set_evacuation_in_progress(in_progress);
1470 MutexLocker mu(Threads_lock);
1471 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1472 }
1473
1474 void ShenandoahHeap::set_evacuation_in_progress_at_safepoint(bool in_progress) {
1475 assert(SafepointSynchronize::is_at_safepoint(), "Only call this at safepoint");
1476 set_evacuation_in_progress(in_progress);
1477 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1478 }
1479
1480 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1481 _evacuation_in_progress = in_progress ? 1 : 0;
1482 OrderAccess::fence();
1483 }
1484
1485 void ShenandoahHeap::oom_during_evacuation() {
1486 log_develop_trace(gc)("Out of memory during evacuation, cancel evacuation, schedule full GC by thread %d",
1487 Thread::current()->osthread()->thread_id());
1488
1489 // We ran out of memory during evacuation. Cancel evacuation, and schedule a full-GC.
1490 collector_policy()->set_should_clear_all_soft_refs(true);
1491 concurrent_thread()->try_set_full_gc();
1492 cancel_concgc(_oom_evacuation);
1493
1494 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
1495 assert(! Threads_lock->owned_by_self()
1496 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here");
1497 log_warning(gc)("OOM during evacuation. Let Java thread wait until evacuation finishes.");
1498 while (_evacuation_in_progress) { // wait.
1499 Thread::current()->_ParkEvent->park(1);
1500 }
1501 }
1502
1503 }
1504
1505 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1506 // Initialize Brooks pointer for the next object
1507 HeapWord* result = obj + BrooksPointer::word_size();
1508 BrooksPointer::initialize(oop(result));
1509 return result;
1510 }
1511
1512 uint ShenandoahHeap::oop_extra_words() {
1513 return BrooksPointer::word_size();
1514 }
1515
1516 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1517 _heap(ShenandoahHeap::heap_no_check()) {
1518 }
1519
1520 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1521 assert(_heap != NULL, "sanity");
1522 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1523 #ifdef ASSERT
1524 if (_heap->concurrent_mark_in_progress()) {
1525 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1526 }
1527 #endif
1528 assert(!oopDesc::is_null(obj), "null");
1529 return _heap->is_marked(obj);
1530 }
1531
1532 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1533 _heap(ShenandoahHeap::heap_no_check()) {
1534 }
1535
1536 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1537 assert(_heap != NULL, "sanity");
1538 assert(!oopDesc::is_null(obj), "null");
1539 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1540 return _heap->is_marked(obj);
1541 }
1542
1543 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1544 return need_update_refs() ?
1545 (BoolObjectClosure*) &_forwarded_is_alive :
1546 (BoolObjectClosure*) &_is_alive;
1547 }
1548
1549 void ShenandoahHeap::ref_processing_init() {
1550 MemRegion mr = reserved_region();
1551
1552 _forwarded_is_alive.init(ShenandoahHeap::heap());
1553 _is_alive.init(ShenandoahHeap::heap());
1554 assert(_max_workers > 0, "Sanity");
1555
1556 _ref_processor =
1557 new ReferenceProcessor(mr, // span
1558 ParallelRefProcEnabled, // MT processing
1559 _max_workers, // Degree of MT processing
1560 true, // MT discovery
1561 _max_workers, // Degree of MT discovery
1562 false, // Reference discovery is not atomic
1563 &_forwarded_is_alive); // Pessimistically assume "forwarded"
1564 }
1565
1566
1567 GCTracer* ShenandoahHeap::tracer() {
1568 return shenandoahPolicy()->tracer();
1569 }
1570
1571 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1572 return _free_regions->used();
1573 }
1574
1575 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1576 if (try_cancel_concgc()) {
1577 log_info(gc)("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1578 _shenandoah_policy->report_concgc_cancelled();
1579 }
1580 }
1581
1582 void ShenandoahHeap::cancel_concgc(ShenandoahCancelCause cause) {
1583 if (try_cancel_concgc()) {
1584 log_info(gc)("Cancelling concurrent GC: %s", cancel_cause_to_string(cause));
1585 _shenandoah_policy->report_concgc_cancelled();
1586 }
1587 }
1588
1589 const char* ShenandoahHeap::cancel_cause_to_string(ShenandoahCancelCause cause) {
1590 switch (cause) {
1591 case _oom_evacuation:
1592 return "Out of memory for evacuation";
1593 case _vm_stop:
1594 return "Stopping VM";
1595 default:
1596 return "Unknown";
1597 }
1598 }
1599
1600 uint ShenandoahHeap::max_workers() {
1601 return _max_workers;
1602 }
1603
1604 void ShenandoahHeap::stop() {
1605 // The shutdown sequence should be able to terminate when GC is running.
1606
1607 // Step 0. Notify policy to disable event recording.
1608 _shenandoah_policy->record_shutdown();
1609
1610 // Step 1. Notify control thread that we are in shutdown.
1611 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1612 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1613 _concurrent_gc_thread->prepare_for_graceful_shutdown();
1614
1615 // Step 2. Notify GC workers that we are cancelling GC.
1616 cancel_concgc(_vm_stop);
1617
1618 // Step 3. Wait until GC worker exits normally.
1619 _concurrent_gc_thread->stop();
1620 }
1621
1622 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1623 ShenandoahPhaseTimings::Phase phase_root =
1624 full_gc ?
1625 ShenandoahPhaseTimings::full_gc_purge :
1626 ShenandoahPhaseTimings::purge;
1627
1628 ShenandoahPhaseTimings::Phase phase_unload =
1629 full_gc ?
1630 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1631 ShenandoahPhaseTimings::purge_class_unload;
1632
1633 ShenandoahPhaseTimings::Phase phase_cldg =
1634 full_gc ?
1635 ShenandoahPhaseTimings::full_gc_purge_cldg :
1636 ShenandoahPhaseTimings::purge_cldg;
1637
1638 ShenandoahPhaseTimings::Phase phase_par =
1639 full_gc ?
1640 ShenandoahPhaseTimings::full_gc_purge_par :
1641 ShenandoahPhaseTimings::purge_par;
1642
1643 ShenandoahPhaseTimings::Phase phase_par_classes =
1644 full_gc ?
1645 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1646 ShenandoahPhaseTimings::purge_par_classes;
1647
1648 ShenandoahPhaseTimings::Phase phase_par_codecache =
1649 full_gc ?
1650 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1651 ShenandoahPhaseTimings::purge_par_codecache;
1652
1653 ShenandoahPhaseTimings::Phase phase_par_rmt =
1654 full_gc ?
1655 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
1656 ShenandoahPhaseTimings::purge_par_rmt;
1657
1658 ShenandoahPhaseTimings::Phase phase_par_symbstring =
1659 full_gc ?
1660 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
1661 ShenandoahPhaseTimings::purge_par_symbstring;
1662
1663 ShenandoahPhaseTimings::Phase phase_par_sync =
1664 full_gc ?
1665 ShenandoahPhaseTimings::full_gc_purge_par_sync :
1666 ShenandoahPhaseTimings::purge_par_sync;
1667
1668 ShenandoahGCPhase root_phase(phase_root);
1669
1670 BoolObjectClosure* is_alive = is_alive_closure();
1671
1672 bool purged_class;
1673
1674 // Unload classes and purge SystemDictionary.
1675 {
1676 ShenandoahGCPhase phase(phase_unload);
1677 purged_class = SystemDictionary::do_unloading(is_alive,
1678 full_gc ? ShenandoahMarkCompact::gc_timer() : gc_timer(),
1679 true);
1680 }
1681
1682 {
1683 ShenandoahGCPhase phase(phase_par);
1684 uint active = _workers->active_workers();
1685 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
1686 _workers->run_task(&unlink_task);
1687
1688 ShenandoahPhaseTimings* p = ShenandoahHeap::heap()->phase_timings();
1689 ParallelCleaningTimes times = unlink_task.times();
1690
1691 // "times" report total time, phase_tables_cc reports wall time. Divide total times
1692 // by active workers to get average time per worker, that would add up to wall time.
1693 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
1694 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
1695 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
1696 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
1697 p->record_phase_time(phase_par_sync, times.sync_us() / active);
1698 }
1699
1700 {
1701 ShenandoahGCPhase phase(phase_cldg);
1702 ClassLoaderDataGraph::purge();
1703 }
1704 }
1705
1706 void ShenandoahHeap::set_need_update_refs(bool need_update_refs) {
1707 _need_update_refs = need_update_refs;
1708 }
1709
1710 //fixme this should be in heapregionset
1711 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
1712 size_t region_idx = r->region_number() + 1;
1713 ShenandoahHeapRegion* next = _ordered_regions->get(region_idx);
1714 guarantee(next->region_number() == region_idx, "region number must match");
1715 while (next->is_humongous()) {
1716 region_idx = next->region_number() + 1;
1717 next = _ordered_regions->get(region_idx);
1718 guarantee(next->region_number() == region_idx, "region number must match");
1719 }
1720 return next;
1721 }
1722
1723 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
1724 return _monitoring_support;
1725 }
1726
1727 MarkBitMap* ShenandoahHeap::mark_bit_map() {
1728 return _mark_bit_map;
1729 }
1730
1731 void ShenandoahHeap::add_free_region(ShenandoahHeapRegion* r) {
1732 _free_regions->add_region(r);
1733 }
1734
1735 void ShenandoahHeap::clear_free_regions() {
1736 _free_regions->clear();
1737 }
1738
1739 address ShenandoahHeap::in_cset_fast_test_addr() {
1740 ShenandoahHeap* heap = ShenandoahHeap::heap();
1741 assert(heap->collection_set() != NULL, "Sanity");
1742 return (address) heap->collection_set()->biased_map_address();
1743 }
1744
1745 address ShenandoahHeap::cancelled_concgc_addr() {
1746 return (address) &(ShenandoahHeap::heap()->_cancelled_concgc);
1747 }
1748
1749
1750 size_t ShenandoahHeap::conservative_max_heap_alignment() {
1751 return ShenandoahMaxRegionSize;
1752 }
1753
1754 size_t ShenandoahHeap::bytes_allocated_since_cm() {
1755 return _bytes_allocated_since_cm;
1756 }
1757
1758 void ShenandoahHeap::set_bytes_allocated_since_cm(size_t bytes) {
1759 _bytes_allocated_since_cm = bytes;
1760 }
1761
1762 void ShenandoahHeap::set_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
1763 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1764 _top_at_mark_starts[index] = addr;
1765 }
1766
1767 HeapWord* ShenandoahHeap::top_at_mark_start(HeapWord* region_base) {
1768 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1769 return _top_at_mark_starts[index];
1770 }
1771
1772 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1773 _full_gc_in_progress = in_progress;
1774 }
1775
1776 bool ShenandoahHeap::is_full_gc_in_progress() const {
1777 return _full_gc_in_progress;
1778 }
1779
1780 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1781 _update_refs_in_progress = in_progress;
1782 }
1783
1784 bool ShenandoahHeap::is_update_refs_in_progress() const {
1785 return _update_refs_in_progress;
1786 }
1787
1788 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1789 ShenandoahCodeRoots::add_nmethod(nm);
1790 }
1791
1792 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
1793 ShenandoahCodeRoots::remove_nmethod(nm);
1794 }
1795
1796 void ShenandoahHeap::pin_object(oop o) {
1797 ShenandoahHeapLocker locker(lock());
1798 heap_region_containing(o)->make_pinned();
1799 }
1800
1801 void ShenandoahHeap::unpin_object(oop o) {
1802 ShenandoahHeapLocker locker(lock());
1803 heap_region_containing(o)->make_unpinned();
1804 }
1805
1806 GCTimer* ShenandoahHeap::gc_timer() const {
1807 return _gc_timer;
1808 }
1809
1810 #ifdef ASSERT
1811 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
1812 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
1813
1814 if (SafepointSynchronize::is_at_safepoint()) {
1815 if (UseDynamicNumberOfGCThreads ||
1816 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
1817 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
1818 } else {
1819 // Use ParallelGCThreads inside safepoints
1820 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
1821 }
1822 } else {
1823 if (UseDynamicNumberOfGCThreads ||
1824 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
1825 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
1826 } else {
1827 // Use ConcGCThreads outside safepoints
1828 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
1829 }
1830 }
1831 }
1832 #endif
1833
1834 class ShenandoahCountGarbageClosure : public ShenandoahHeapRegionClosure {
1835 private:
1836 size_t _garbage;
1837 public:
1838 ShenandoahCountGarbageClosure() : _garbage(0) {
1839 }
1840
1841 bool heap_region_do(ShenandoahHeapRegion* r) {
1842 if (r->is_regular()) {
1843 _garbage += r->garbage();
1844 }
1845 return false;
1846 }
1847
1848 size_t garbage() {
1849 return _garbage;
1850 }
1851 };
1852
1853 size_t ShenandoahHeap::garbage() {
1854 ShenandoahCountGarbageClosure cl;
1855 heap_region_iterate(&cl);
1856 return cl.garbage();
1857 }
1858
1859 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
1860 return _connection_matrix;
1861 }
1862
1863 ShenandoahPartialGC* ShenandoahHeap::partial_gc() {
1864 return _partial_gc;
1865 }
1866
1867 void ShenandoahHeap::do_partial_collection() {
1868 partial_gc()->do_partial_collection();
1869 }
1870
1871 ShenandoahVerifier* ShenandoahHeap::verifier() {
1872 guarantee(ShenandoahVerify, "Should be enabled");
1873 assert (_verifier != NULL, "sanity");
1874 return _verifier;
1875 }
1876
1877 template<class T>
1878 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
1879 private:
1880 T cl;
1881 ShenandoahHeap* _heap;
1882 ShenandoahHeapRegionSet* _regions;
1883 bool _concurrent;
1884 public:
1885 ShenandoahUpdateHeapRefsTask(ShenandoahHeapRegionSet* regions, bool concurrent) :
1886 AbstractGangTask("Concurrent Update References Task"),
1887 cl(T()),
1888 _heap(ShenandoahHeap::heap()),
1889 _regions(regions),
1890 _concurrent(concurrent) {
1891 }
1892
1893 void work(uint worker_id) {
1894 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
1895 ShenandoahHeapRegion* r = _regions->claim_next();
1896 while (r != NULL) {
1897 if (_heap->in_collection_set(r)) {
1898 HeapWord* bottom = r->bottom();
1899 HeapWord* top = _heap->top_at_mark_start(r->bottom());
1900 if (top > bottom) {
1901 _heap->mark_bit_map()->clear_range_large(MemRegion(bottom, top));
1902 }
1903 } else {
1904 if (r->is_active()) {
1905 _heap->marked_object_oop_safe_iterate(r, &cl);
1906 }
1907 }
1908 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
1909 return;
1910 }
1911 r = _regions->claim_next();
1912 }
1913 }
1914 };
1915
1916 void ShenandoahHeap::update_heap_references(ShenandoahHeapRegionSet* update_regions, bool concurrent) {
1917 if (UseShenandoahMatrix) {
1918 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(update_regions, concurrent);
1919 workers()->run_task(&task);
1920 } else {
1921 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(update_regions, concurrent);
1922 workers()->run_task(&task);
1923 }
1924 }
1925
1926 void ShenandoahHeap::concurrent_update_heap_references() {
1927 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
1928 ShenandoahHeapRegionSet* update_regions = regions();
1929 update_regions->clear_current_index();
1930 update_heap_references(update_regions, true);
1931 }
1932
1933 void ShenandoahHeap::prepare_update_refs() {
1934 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1935
1936 if (ShenandoahVerify) {
1937 verifier()->verify_before_updaterefs();
1938 }
1939
1940 set_evacuation_in_progress_at_safepoint(false);
1941 set_update_refs_in_progress(true);
1942 ensure_parsability(true);
1943 if (UseShenandoahMatrix) {
1944 connection_matrix()->clear_all();
1945 }
1946 for (uint i = 0; i < num_regions(); i++) {
1947 ShenandoahHeapRegion* r = _ordered_regions->get(i);
1948 r->set_concurrent_iteration_safe_limit(r->top());
1949 }
1950 }
1951
1952 void ShenandoahHeap::finish_update_refs() {
1953 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1954
1955 if (cancelled_concgc()) {
1956 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
1957
1958 // Finish updating references where we left off.
1959 clear_cancelled_concgc();
1960 ShenandoahHeapRegionSet* update_regions = regions();
1961 update_heap_references(update_regions, false);
1962 }
1963
1964 assert(! cancelled_concgc(), "Should have been done right before");
1965 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
1966
1967 if (ShenandoahStringDedup::is_enabled()) {
1968 ShenandoahGCPhase final_str_dedup_table(ShenandoahPhaseTimings::final_update_refs_dedup_table);
1969 ShenandoahStringDedup::parallel_update_refs();
1970 }
1971
1972 // Allocations might have happened before we STWed here, record peak:
1973 shenandoahPolicy()->record_peak_occupancy();
1974
1975 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
1976
1977 trash_cset_regions();
1978 set_need_update_refs(false);
1979
1980 if (ShenandoahVerify) {
1981 verifier()->verify_after_updaterefs();
1982 }
1983
1984 {
1985 // Rebuild the free set
1986 ShenandoahHeapLocker locker(lock());
1987 _free_regions->clear();
1988 size_t end = _ordered_regions->active_regions();
1989 for (size_t i = 0; i < end; i++) {
1990 ShenandoahHeapRegion* r = _ordered_regions->get(i);
1991 if (r->is_alloc_allowed()) {
1992 assert (!in_collection_set(r), "collection set should be clear");
1993 _free_regions->add_region(r);
1994 }
1995 }
1996 }
1997 set_update_refs_in_progress(false);
1998 }
1999
2000 void ShenandoahHeap::set_alloc_seq_gc_start() {
2001 // Take next number, the start seq number is inclusive
2002 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::alloc_seq_num() + 1;
2003 }
2004
2005 void ShenandoahHeap::set_alloc_seq_gc_end() {
2006 // Take current number, the end seq number is also inclusive
2007 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::alloc_seq_num();
2008 }
2009
2010
2011 #ifdef ASSERT
2012 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2013 _lock.assert_owned_by_current_thread();
2014 }
2015
2016 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2017 _lock.assert_not_owned_by_current_thread();
2018 }
2019
2020 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2021 _lock.assert_owned_by_current_thread_or_safepoint();
2022 }
2023 #endif
2024
2025 void ShenandoahHeap::recycle_trash_assist(size_t limit) {
2026 assert_heaplock_owned_by_current_thread();
2027
2028 size_t count = 0;
2029 for (size_t i = 0; (i < num_regions()) && (count < limit); i++) {
2030 ShenandoahHeapRegion *r = _ordered_regions->get(i);
2031 if (r->is_trash()) {
2032 decrease_used(r->used());
2033 r->recycle();
2034 _free_regions->add_region(r);
2035 count++;
2036 }
2037 }
2038 }
2039
2040 void ShenandoahHeap::recycle_trash() {
2041 // lock is not reentrable, check we don't have it
2042 assert_heaplock_not_owned_by_current_thread();
2043
2044 size_t bytes_reclaimed = 0;
2045
2046 if (UseShenandoahMatrix) {
2047 // The complication for matrix cleanup is that we want the batched update
2048 // to alleviate costs. We also cannot add regions to freeset until matrix
2049 // is clean, otherwise we race with the actual allocations.
2050
2051 size_t count = 0;
2052 for (size_t i = 0; i < num_regions(); i++) {
2053 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2054 if (r->is_trash()) {
2055 ShenandoahHeapLocker locker(lock());
2056 if (r->is_trash()) {
2057 bytes_reclaimed += r->used();
2058 decrease_used(r->used());
2059 r->recycle_no_matrix();
2060 _recycled_regions[count++] = r->region_number();
2061 }
2062 }
2063 SpinPause(); // allow allocators to barge the lock
2064 }
2065
2066 connection_matrix()->clear_batched(_recycled_regions, count);
2067
2068 {
2069 ShenandoahHeapLocker locker(lock());
2070 for (size_t i = 0; i < count; i++) {
2071 ShenandoahHeapRegion *r = _ordered_regions->get(_recycled_regions[i]);
2072 _free_regions->add_region(r);
2073 }
2074 }
2075
2076 } else {
2077 for (size_t i = 0; i < num_regions(); i++) {
2078 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2079 if (r->is_trash()) {
2080 ShenandoahHeapLocker locker(lock());
2081 if (r->is_trash()) {
2082 bytes_reclaimed += r->used();
2083 decrease_used(r->used());
2084 r->recycle();
2085 _free_regions->add_region(r);
2086 }
2087 }
2088 SpinPause(); // allow allocators to barge the lock
2089 }
2090 }
2091
2092 _shenandoah_policy->record_bytes_reclaimed(bytes_reclaimed);
2093 }
2094
2095 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2096 print_on(st);
2097 print_heap_regions_on(st);
2098 }
2099
2100 bool ShenandoahHeap::commit_bitmaps(ShenandoahHeapRegion* r) {
2101 size_t len = _bitmap_words_per_region * HeapWordSize;
2102 size_t off = r->region_number() * _bitmap_words_per_region;
2103 if (!os::commit_memory((char*)(_bitmap_region.start() + off), len, false)) {
2104 return false;
2105 }
2106 return true;
2107 }
2108
2109 bool ShenandoahHeap::uncommit_bitmaps(ShenandoahHeapRegion* r) {
2110 size_t len = _bitmap_words_per_region * HeapWordSize;
2111 size_t off = r->region_number() * _bitmap_words_per_region;
2112 if (!os::uncommit_memory((char*)(_bitmap_region.start() + off), len)) {
2113 return false;
2114 }
2115 return true;
2116 }