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 #include "gc/shared/plab.hpp"
31
32 #include "gc/shenandoah/brooksPointer.hpp"
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
36 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
47 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
48 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
49 #include "gc/shenandoah/shenandoahPacer.hpp"
50 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
51 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
52 #include "gc/shenandoah/shenandoahStringDedup.hpp"
53 #include "gc/shenandoah/shenandoahUtils.hpp"
54 #include "gc/shenandoah/shenandoahVerifier.hpp"
55 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
56 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
57 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
58
59 #include "runtime/vmThread.hpp"
60 #include "services/mallocTracker.hpp"
61
62 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
63
64 #ifdef ASSERT
65 template <class T>
66 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
67 T o = oopDesc::load_heap_oop(p);
68 if (! oopDesc::is_null(o)) {
69 oop obj = oopDesc::decode_heap_oop_not_null(o);
70 shenandoah_assert_not_forwarded(p, obj);
71 }
72 }
73
74 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
75 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
76 #endif
77
78 const char* ShenandoahHeap::name() const {
79 return "Shenandoah";
80 }
81
82 class ShenandoahPretouchTask : public AbstractGangTask {
83 private:
84 ShenandoahRegionIterator _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(char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
91 size_t page_size) :
92 AbstractGangTask("Shenandoah PreTouch",
93 Universe::is_fully_initialized() ? GCId::current_raw() :
94 // During VM initialization there is
95 // no GC cycle that this task can be
96 // associated with.
97 GCId::undefined()),
98 _bitmap0_base(bitmap0_base),
99 _bitmap1_base(bitmap1_base),
100 _bitmap_size(bitmap_size),
101 _page_size(page_size) {}
102
103 virtual void work(uint worker_id) {
104 ShenandoahHeapRegion* r = _regions.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(_bitmap0_base + start), p2i(_bitmap0_base + end));
116 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
117
118 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
119 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
120 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
121
122 r = _regions.next();
123 }
124 }
125 };
126
127 jint ShenandoahHeap::initialize() {
128 CollectedHeap::pre_initialize();
129
130 BrooksPointer::initial_checks();
131
132 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
133 size_t max_byte_size = collector_policy()->max_heap_byte_size();
134 size_t heap_alignment = collector_policy()->heap_alignment();
135
136 if (ShenandoahAlwaysPreTouch) {
137 // Enabled pre-touch means the entire heap is committed right away.
138 init_byte_size = max_byte_size;
139 }
140
141 Universe::check_alignment(max_byte_size,
142 ShenandoahHeapRegion::region_size_bytes(),
143 "shenandoah heap");
144 Universe::check_alignment(init_byte_size,
145 ShenandoahHeapRegion::region_size_bytes(),
146 "shenandoah heap");
147
148 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
149 heap_alignment);
150 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
151
152 set_barrier_set(new ShenandoahBarrierSet(this));
153 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
154
155 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
156 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
157 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
158 _committed = _initial_size;
159
160 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
161 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
162 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
163 }
164
165 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
166 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
167
168 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
169 _free_set = new ShenandoahFreeSet(this, _num_regions);
170
171 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
172
173 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
174 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
175 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
176
177 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
178 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
179 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
180
181 if (ShenandoahPacing) {
182 _pacer = new ShenandoahPacer(this);
183 _pacer->setup_for_idle();
184 } else {
185 _pacer = NULL;
186 }
187
188 {
189 ShenandoahHeapLocker locker(lock());
190 for (size_t i = 0; i < _num_regions; i++) {
191 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
192 (HeapWord*) pgc_rs.base() + reg_size_words * i,
193 reg_size_words,
194 i,
195 i < num_committed_regions);
196
197 _complete_top_at_mark_starts_base[i] = r->bottom();
198 _next_top_at_mark_starts_base[i] = r->bottom();
199 _regions[i] = r;
200 assert(!collection_set()->is_in(i), "New region should not be in collection set");
201 }
202
203 _free_set->rebuild();
204 }
205
206 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
207 "misaligned heap: "PTR_FORMAT, p2i(base()));
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 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
218 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
219 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
220 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
221
222 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
223
224 guarantee(bitmap_bytes_per_region != 0,
225 "Bitmap bytes per region should not be zero");
226 guarantee(is_power_of_2(bitmap_bytes_per_region),
227 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
228
229 if (bitmap_page_size > bitmap_bytes_per_region) {
230 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
231 _bitmap_bytes_per_slice = bitmap_page_size;
232 } else {
233 _bitmap_regions_per_slice = 1;
234 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
235 }
236
237 guarantee(_bitmap_regions_per_slice >= 1,
238 "Should have at least one region per slice: " SIZE_FORMAT,
239 _bitmap_regions_per_slice);
240
241 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
242 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
243 _bitmap_bytes_per_slice, bitmap_page_size);
244
245 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
246 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
247 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
248
249 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
250 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
251 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
252
253 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
254 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
255 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
256 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
257 "couldn't allocate initial bitmap");
258 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
259 "couldn't allocate initial bitmap");
260
261 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
262
263 if (ShenandoahVerify) {
264 ReservedSpace verify_bitmap(_bitmap_size, page_size);
265 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
266 "couldn't allocate verification bitmap");
267 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
268 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
269 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
270 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
271 }
272
273 if (ShenandoahAlwaysPreTouch) {
274 assert (!AlwaysPreTouch, "Should have been overridden");
275
276 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
277 // before initialize() below zeroes it with initializing thread. For any given region,
278 // we touch the region and the corresponding bitmaps from the same thread.
279
280 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
281 _num_regions, page_size);
282 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
283 _workers->run_task(&cl);
284 }
285
286 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
287 _complete_mark_bit_map = &_mark_bit_map0;
288
289 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
290 _next_mark_bit_map = &_mark_bit_map1;
291
292 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
293 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
294 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
295 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
296 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
297
298 if (UseShenandoahMatrix) {
299 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
300 } else {
301 _connection_matrix = NULL;
302 }
303
304 _traversal_gc = _shenandoah_policy->can_do_traversal_gc() ?
305 new ShenandoahTraversalGC(this, _num_regions) :
306 NULL;
307
308 _monitoring_support = new ShenandoahMonitoringSupport(this);
309
310 _phase_timings = new ShenandoahPhaseTimings();
311
312 if (ShenandoahAllocationTrace) {
313 _alloc_tracker = new ShenandoahAllocTracker();
314 }
315
316 ShenandoahStringDedup::initialize();
317
318 _control_thread = new ShenandoahControlThread();
319
320 ShenandoahCodeRoots::initialize();
321
322 LogTarget(Trace, gc, region) lt;
323 if (lt.is_enabled()) {
324 ResourceMark rm;
325 LogStream ls(lt);
326 log_trace(gc, region)("All Regions");
327 print_heap_regions_on(&ls);
328 log_trace(gc, region)("Free Regions");
329 _free_set->print_on(&ls);
330 }
331
332 log_info(gc, init)("Safepointing mechanism: %s",
333 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
334 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
335
336 return JNI_OK;
337 }
338
339 #ifdef _MSC_VER
340 #pragma warning( push )
341 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
342 #endif
343
344 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
345 CollectedHeap(),
346 _shenandoah_policy(policy),
347 _regions(NULL),
348 _free_set(NULL),
349 _collection_set(NULL),
350 _update_refs_iterator(this),
351 _bytes_allocated_since_gc_start(0),
352 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
353 _ref_processor(NULL),
354 _next_top_at_mark_starts(NULL),
355 _next_top_at_mark_starts_base(NULL),
356 _complete_top_at_mark_starts(NULL),
357 _complete_top_at_mark_starts_base(NULL),
358 _mark_bit_map0(),
359 _mark_bit_map1(),
360 _aux_bit_map(),
361 _connection_matrix(NULL),
362 _verifier(NULL),
363 _pacer(NULL),
364 _used_at_last_gc(0),
365 _alloc_seq_at_last_gc_start(0),
366 _alloc_seq_at_last_gc_end(0),
367 _safepoint_workers(NULL),
368 _gc_cycle_mode(),
369 #ifdef ASSERT
370 _heap_expansion_count(0),
371 #endif
372 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
373 _phase_timings(NULL),
374 _alloc_tracker(NULL),
375 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
376 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
377 _mutator_gclab_stats(new PLABStats("Shenandoah mutator GCLAB stats", OldPLABSize, PLABWeight)),
378 _collector_gclab_stats(new PLABStats("Shenandoah collector GCLAB stats", YoungPLABSize, PLABWeight)),
379 _memory_pool(NULL)
380 {
381 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
382 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
383 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
384
385 _scm = new ShenandoahConcurrentMark();
386 _full_gc = new ShenandoahMarkCompact();
387 _used = 0;
388
389 _max_workers = MAX2(_max_workers, 1U);
390 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
391 /* are_GC_task_threads */true,
392 /* are_ConcurrentGC_threads */false);
393 if (_workers == NULL) {
394 vm_exit_during_initialization("Failed necessary allocation.");
395 } else {
396 _workers->initialize_workers();
397 }
398
399 if (ParallelSafepointCleanupThreads > 1) {
400 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
401 ParallelSafepointCleanupThreads,
402 false, false);
403 _safepoint_workers->initialize_workers();
404 }
405 }
406
407 #ifdef _MSC_VER
408 #pragma warning( pop )
409 #endif
410
411 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
412 private:
413 ShenandoahRegionIterator _regions;
414
415 public:
416 ShenandoahResetNextBitmapTask() :
417 AbstractGangTask("Parallel Reset Bitmap Task") {}
418
419 void work(uint worker_id) {
420 ShenandoahHeapRegion* region = _regions.next();
421 ShenandoahHeap* heap = ShenandoahHeap::heap();
422 while (region != NULL) {
423 if (heap->is_bitmap_slice_committed(region)) {
424 HeapWord* bottom = region->bottom();
425 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
426 if (top > bottom) {
427 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
428 }
429 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
430 }
431 region = _regions.next();
432 }
433 }
434 };
435
436 void ShenandoahHeap::reset_next_mark_bitmap() {
437 assert_gc_workers(_workers->active_workers());
438
439 ShenandoahResetNextBitmapTask task;
440 _workers->run_task(&task);
441 }
442
443 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
444 private:
445 ShenandoahRegionIterator _regions;
446
447 public:
448 ShenandoahResetNextBitmapTraversalTask() :
449 AbstractGangTask("Parallel Reset Bitmap Task for Traversal") {}
450
451 void work(uint worker_id) {
452 ShenandoahHeap* heap = ShenandoahHeap::heap();
453 ShenandoahHeapRegionSet* traversal_set = heap->traversal_gc()->traversal_set();
454 ShenandoahHeapRegion* region = _regions.next();
455 while (region != NULL) {
456 if (heap->is_bitmap_slice_committed(region)) {
457 if (traversal_set->is_in(region) && !region->is_trash()) {
458 ShenandoahHeapLocker locker(heap->lock());
459 HeapWord* bottom = region->bottom();
460 HeapWord* top = heap->next_top_at_mark_start(bottom);
461 assert(top <= region->top(),
462 "TAMS must smaller/equals than top: TAMS: "PTR_FORMAT", top: "PTR_FORMAT,
463 p2i(top), p2i(region->top()));
464 if (top > bottom) {
465 heap->complete_mark_bit_map()->copy_from(heap->next_mark_bit_map(), MemRegion(bottom, top));
466 heap->set_complete_top_at_mark_start(bottom, top);
467 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
468 heap->set_next_top_at_mark_start(bottom, bottom);
469 }
470 }
471 assert(heap->is_next_bitmap_clear_range(region->bottom(), region->end()),
472 "need clear next bitmap");
473 }
474 region = _regions.next();
475 }
476 }
477 };
478
479 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
480 assert_gc_workers(_workers->active_workers());
481
482 ShenandoahResetNextBitmapTraversalTask task;
483 _workers->run_task(&task);
484 }
485
486 bool ShenandoahHeap::is_next_bitmap_clear() {
487 for (size_t idx = 0; idx < _num_regions; idx++) {
488 ShenandoahHeapRegion* r = get_region(idx);
489 if (is_bitmap_slice_committed(r) && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
490 return false;
491 }
492 }
493 return true;
494 }
495
496 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
497 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
498 }
499
500 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
501 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
502 }
503
504 void ShenandoahHeap::print_on(outputStream* st) const {
505 st->print_cr("Shenandoah Heap");
506 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
507 capacity() / K, committed() / K, used() / K);
508 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
509 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
510
511 st->print("Status: ");
512 if (has_forwarded_objects()) st->print("has forwarded objects, ");
513 if (is_concurrent_mark_in_progress()) st->print("marking, ");
514 if (is_evacuation_in_progress()) st->print("evacuating, ");
515 if (is_update_refs_in_progress()) st->print("updating refs, ");
516 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
517 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
518 if (is_full_gc_in_progress()) st->print("full gc, ");
519 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
520
521 if (cancelled_concgc()) {
522 st->print("conc gc cancelled");
523 } else {
524 st->print("not cancelled");
525 }
526 st->cr();
527
528 st->print_cr("Reserved region:");
529 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
530 p2i(reserved_region().start()),
531 p2i(reserved_region().end()));
532
533 if (UseShenandoahMatrix) {
534 st->print_cr("Matrix:");
535
536 ShenandoahConnectionMatrix* matrix = connection_matrix();
537 if (matrix != NULL) {
538 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
539 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
540 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
541 } else {
542 st->print_cr(" No matrix.");
543 }
544 }
545
546 if (Verbose) {
547 print_heap_regions_on(st);
548 }
549 }
550
551 class ShenandoahInitGCLABClosure : public ThreadClosure {
552 public:
553 void do_thread(Thread* thread) {
554 ShenandoahHeap::heap()->initialize_gclab(thread);
555 }
556 };
557
558 void ShenandoahHeap::post_initialize() {
559 CollectedHeap::post_initialize();
560 MutexLocker ml(Threads_lock);
561
562 ShenandoahInitGCLABClosure init_gclabs;
563 Threads::java_threads_do(&init_gclabs);
564 gc_threads_do(&init_gclabs);
565
566 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
567 // Now, we will let WorkGang to initialize gclab when new worker is created.
568 _workers->set_initialize_gclab();
569
570 _scm->initialize(_max_workers);
571 _full_gc->initialize(_gc_timer);
572
573 ref_processing_init();
574
575 _shenandoah_policy->post_heap_initialize();
576 }
577
578 size_t ShenandoahHeap::used() const {
579 return OrderAccess::load_acquire(&_used);
580 }
581
582 size_t ShenandoahHeap::committed() const {
583 OrderAccess::acquire();
584 return _committed;
585 }
586
587 void ShenandoahHeap::increase_committed(size_t bytes) {
588 assert_heaplock_or_safepoint();
589 _committed += bytes;
590 }
591
592 void ShenandoahHeap::decrease_committed(size_t bytes) {
593 assert_heaplock_or_safepoint();
594 _committed -= bytes;
595 }
596
597 void ShenandoahHeap::increase_used(size_t bytes) {
598 Atomic::add(bytes, &_used);
599 }
600
601 void ShenandoahHeap::set_used(size_t bytes) {
602 OrderAccess::release_store_fence(&_used, bytes);
603 }
604
605 void ShenandoahHeap::decrease_used(size_t bytes) {
606 assert(used() >= bytes, "never decrease heap size by more than we've left");
607 Atomic::sub(bytes, &_used);
608 }
609
610 void ShenandoahHeap::increase_allocated(size_t bytes) {
611 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
612 }
613
614 void ShenandoahHeap::notify_alloc(size_t words, bool waste) {
615 size_t bytes = words * HeapWordSize;
616 if (!waste) {
617 increase_used(bytes);
618 }
619 increase_allocated(bytes);
620 if (ShenandoahPacing) {
621 control_thread()->pacing_notify_alloc(words);
622 if (waste) {
623 pacer()->claim_for_alloc(words, true);
624 }
625 }
626 }
627
628 size_t ShenandoahHeap::capacity() const {
629 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
630 }
631
632 bool ShenandoahHeap::is_maximal_no_gc() const {
633 Unimplemented();
634 return true;
635 }
636
637 size_t ShenandoahHeap::max_capacity() const {
638 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
639 }
640
641 size_t ShenandoahHeap::initial_capacity() const {
642 return _initial_size;
643 }
644
645 bool ShenandoahHeap::is_in(const void* p) const {
646 HeapWord* heap_base = (HeapWord*) base();
647 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
648 return p >= heap_base && p < last_region_end;
649 }
650
651 bool ShenandoahHeap::is_scavengable(oop p) {
652 return true;
653 }
654
655 void ShenandoahHeap::handle_heap_shrinkage(double shrink_before) {
656 if (!ShenandoahUncommit) {
657 return;
658 }
659
660 ShenandoahHeapLocker locker(lock());
661
662 size_t count = 0;
663 for (size_t i = 0; i < num_regions(); i++) {
664 ShenandoahHeapRegion* r = get_region(i);
665 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
666 r->make_uncommitted();
667 count++;
668 }
669 }
670
671 if (count > 0) {
672 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
673 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
674 _control_thread->notify_heap_changed();
675 }
676 }
677
678 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
679 // Retain tlab and allocate object in shared space if
680 // the amount free in the tlab is too large to discard.
681 PLAB* gclab = thread->gclab();
682
683 // Discard gclab and allocate a new one.
684 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
685 gclab->retire();
686 // Figure out size of new GCLAB
687 size_t new_gclab_size;
688 if (thread->is_Java_thread()) {
689 new_gclab_size = _mutator_gclab_stats->desired_plab_sz(Threads::number_of_threads());
690 } else {
691 new_gclab_size = _collector_gclab_stats->desired_plab_sz(workers()->active_workers());
692 }
693
694 // Allocate a new GCLAB...
695 HeapWord* gclab_buf = allocate_new_gclab(new_gclab_size);
696 if (gclab_buf == NULL) {
697 return NULL;
698 }
699
700 if (ZeroTLAB) {
701 // ..and clear it.
702 Copy::zero_to_words(gclab_buf, new_gclab_size);
703 } else {
704 // ...and zap just allocated object.
705 #ifdef ASSERT
706 // Skip mangling the space corresponding to the object header to
707 // ensure that the returned space is not considered parsable by
708 // any concurrent GC thread.
709 size_t hdr_size = oopDesc::header_size();
710 Copy::fill_to_words(gclab_buf + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
711 #endif // ASSERT
712 }
713 gclab->set_buf(gclab_buf, new_gclab_size);
714 return gclab->allocate(size);
715 }
716
717 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
718 #ifdef ASSERT
719 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
720 #endif
721 return allocate_new_lab(word_size, _alloc_tlab);
722 }
723
724 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
725 #ifdef ASSERT
726 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
727 #endif
728 return allocate_new_lab(word_size, _alloc_gclab);
729 }
730
731 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
732 HeapWord* result = allocate_memory(word_size, type);
733
734 if (result != NULL) {
735 assert(! in_collection_set(result), "Never allocate in collection set");
736
737 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
738
739 }
740 return result;
741 }
742
743 ShenandoahHeap* ShenandoahHeap::heap() {
744 CollectedHeap* heap = Universe::heap();
745 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
746 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
747 return (ShenandoahHeap*) heap;
748 }
749
750 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
751 CollectedHeap* heap = Universe::heap();
752 return (ShenandoahHeap*) heap;
753 }
754
755 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
756 ShenandoahAllocTrace trace_alloc(word_size, type);
757
758 bool in_new_region = false;
759 HeapWord* result = NULL;
760
761 if (type == _alloc_tlab || type == _alloc_shared) {
762 if (ShenandoahPacing) {
763 pacer()->pace_for_alloc(word_size);
764 }
765
766 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
767 result = allocate_memory_under_lock(word_size, type, in_new_region);
768 }
769
770 // Allocation failed, try full-GC, then retry allocation.
771 //
772 // It might happen that one of the threads requesting allocation would unblock
773 // way later after full-GC happened, only to fail the second allocation, because
774 // other threads have already depleted the free storage. In this case, a better
775 // strategy would be to try full-GC again.
776 //
777 // Lacking the way to detect progress from "collect" call, we are left with blindly
778 // retrying for some bounded number of times.
779 // TODO: Poll if Full GC made enough progress to warrant retry.
780 int tries = 0;
781 while ((result == NULL) && (tries++ < ShenandoahAllocGCTries)) {
782 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing GC, try %d",
783 p2i(Thread::current()), word_size * HeapWordSize, tries);
784 control_thread()->handle_alloc_failure(word_size);
785 result = allocate_memory_under_lock(word_size, type, in_new_region);
786 }
787 } else {
788 assert(type == _alloc_gclab || type == _alloc_shared_gc, "Can only accept these types here");
789 result = allocate_memory_under_lock(word_size, type, in_new_region);
790 // Do not call handle_alloc_failure() here, because we cannot block.
791 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
792 }
793
794 if (in_new_region) {
795 control_thread()->notify_heap_changed();
796 }
797
798 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
799 word_size, p2i(result), Thread::current()->osthread()->thread_id());
800
801 if (result != NULL) {
802 notify_alloc(word_size, false);
803 }
804
805 return result;
806 }
807
808 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
809 ShenandoahHeapLocker locker(lock());
810 return _free_set->allocate(word_size, type, in_new_region);
811 }
812
813 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
814 bool* gc_overhead_limit_was_exceeded) {
815 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
816 HeapWord* result = filler + BrooksPointer::word_size();
817 if (filler != NULL) {
818 BrooksPointer::initialize(oop(result));
819
820 assert(! in_collection_set(result), "never allocate in targetted region");
821 return result;
822 } else {
823 return NULL;
824 }
825 }
826
827 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
828 private:
829 ShenandoahHeap* _heap;
830 Thread* _thread;
831 public:
832 ShenandoahEvacuateUpdateRootsClosure() :
833 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
834 }
835
836 private:
837 template <class T>
838 void do_oop_work(T* p) {
839 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
840
841 T o = oopDesc::load_heap_oop(p);
842 if (! oopDesc::is_null(o)) {
843 oop obj = oopDesc::decode_heap_oop_not_null(o);
844 if (_heap->in_collection_set(obj)) {
845 shenandoah_assert_marked_complete(p, obj);
846 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
847 if (oopDesc::unsafe_equals(resolved, obj)) {
848 resolved = _heap->evacuate_object(obj, _thread);
849 }
850 oopDesc::encode_store_heap_oop(p, resolved);
851 }
852 }
853 }
854
855 public:
856 void do_oop(oop* p) {
857 do_oop_work(p);
858 }
859 void do_oop(narrowOop* p) {
860 do_oop_work(p);
861 }
862 };
863
864 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
865 private:
866 ShenandoahHeap* _heap;
867 Thread* _thread;
868 public:
869 ShenandoahEvacuateRootsClosure() :
870 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
871 }
872
873 private:
874 template <class T>
875 void do_oop_work(T* p) {
876 T o = oopDesc::load_heap_oop(p);
877 if (! oopDesc::is_null(o)) {
878 oop obj = oopDesc::decode_heap_oop_not_null(o);
879 if (_heap->in_collection_set(obj)) {
880 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
881 if (oopDesc::unsafe_equals(resolved, obj)) {
882 _heap->evacuate_object(obj, _thread);
883 }
884 }
885 }
886 }
887
888 public:
889 void do_oop(oop* p) {
890 do_oop_work(p);
891 }
892 void do_oop(narrowOop* p) {
893 do_oop_work(p);
894 }
895 };
896
897 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
898 private:
899 ShenandoahHeap* const _heap;
900 Thread* const _thread;
901 public:
902 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
903 _heap(heap), _thread(Thread::current()) {}
904
905 void do_object(oop p) {
906 shenandoah_assert_marked_complete(NULL, p);
907 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
908 _heap->evacuate_object(p, _thread);
909 }
910 }
911 };
912
913 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
914 private:
915 ShenandoahHeap* const _sh;
916 ShenandoahCollectionSet* const _cs;
917 ShenandoahSharedFlag _claimed_codecache;
918
919 public:
920 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
921 ShenandoahCollectionSet* cs) :
922 AbstractGangTask("Parallel Evacuation Task"),
923 _cs(cs),
924 _sh(sh)
925 {}
926
927 void work(uint worker_id) {
928
929 ShenandoahEvacOOMScope oom_evac_scope;
930 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
931
932 // If concurrent code cache evac is enabled, evacuate it here.
933 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
934 // nmethods. The update would be handled elsewhere.
935 if (ShenandoahConcurrentEvacCodeRoots && _claimed_codecache.try_set()) {
936 ShenandoahEvacuateRootsClosure cl;
937 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
938 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
939 CodeCache::blobs_do(&blobs);
940 }
941
942 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
943 ShenandoahHeapRegion* r;
944 while ((r =_cs->claim_next()) != NULL) {
945 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
946 worker_id,
947 r->region_number());
948
949 assert(r->has_live(), "all-garbage regions are reclaimed early");
950 _sh->marked_object_iterate(r, &cl);
951
952 if (_sh->check_cancelled_concgc_and_yield()) {
953 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
954 break;
955 }
956
957 if (ShenandoahPacing) {
958 _sh->pacer()->report_evac(r->get_live_data_words());
959 }
960 }
961 }
962 };
963
964 void ShenandoahHeap::trash_cset_regions() {
965 ShenandoahHeapLocker locker(lock());
966
967 ShenandoahCollectionSet* set = collection_set();
968 ShenandoahHeapRegion* r;
969 set->clear_current_index();
970 while ((r = set->next()) != NULL) {
971 r->make_trash();
972 }
973 collection_set()->clear();
974 }
975
976 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
977 st->print_cr("Heap Regions:");
978 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
979 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
980 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
981 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
982
983 for (size_t i = 0; i < num_regions(); i++) {
984 get_region(i)->print_on(st);
985 }
986 }
987
988 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
989 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
990
991 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
992 size_t size = humongous_obj->size() + BrooksPointer::word_size();
993 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
994 size_t index = start->region_number() + required_regions - 1;
995
996 assert(!start->has_live(), "liveness must be zero");
997 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
998
999 for(size_t i = 0; i < required_regions; i++) {
1000 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1001 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1002 ShenandoahHeapRegion* region = get_region(index --);
1003
1004 LogTarget(Trace, gc, humongous) lt;
1005 if (lt.is_enabled()) {
1006 ResourceMark rm;
1007 LogStream ls(lt);
1008 region->print_on(&ls);
1009 }
1010
1011 assert(region->is_humongous(), "expect correct humongous start or continuation");
1012 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1013
1014 region->make_trash();
1015 }
1016 }
1017
1018 #ifdef ASSERT
1019 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1020 bool heap_region_do(ShenandoahHeapRegion* r) {
1021 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1022 return false;
1023 }
1024 };
1025 #endif
1026
1027 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1028 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1029
1030 if (!cancelled_concgc()) {
1031 // Allocations might have happened before we STWed here, record peak:
1032 shenandoahPolicy()->record_peak_occupancy();
1033
1034 make_tlabs_parsable(true);
1035
1036 if (ShenandoahVerify) {
1037 verifier()->verify_after_concmark();
1038 }
1039
1040 trash_cset_regions();
1041
1042 // NOTE: This needs to be done during a stop the world pause, because
1043 // putting regions into the collection set concurrently with Java threads
1044 // will create a race. In particular, acmp could fail because when we
1045 // resolve the first operand, the containing region might not yet be in
1046 // the collection set, and thus return the original oop. When the 2nd
1047 // operand gets resolved, the region could be in the collection set
1048 // and the oop gets evacuated. If both operands have originally been
1049 // the same, we get false negatives.
1050
1051 {
1052 ShenandoahHeapLocker locker(lock());
1053 _collection_set->clear();
1054 _free_set->clear();
1055
1056 #ifdef ASSERT
1057 ShenandoahCheckCollectionSetClosure ccsc;
1058 heap_region_iterate(&ccsc);
1059 #endif
1060
1061 _shenandoah_policy->choose_collection_set(_collection_set);
1062
1063 _free_set->rebuild();
1064 }
1065
1066 Universe::update_heap_info_at_gc();
1067
1068 if (ShenandoahVerify) {
1069 verifier()->verify_before_evacuation();
1070 }
1071 }
1072 }
1073
1074
1075 class ShenandoahRetireTLABClosure : public ThreadClosure {
1076 private:
1077 bool _retire;
1078
1079 public:
1080 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1081
1082 void do_thread(Thread* thread) {
1083 PLAB* gclab = thread->gclab();
1084 if (gclab != NULL) {
1085 gclab->retire();
1086 }
1087 }
1088 };
1089
1090 void ShenandoahHeap::make_tlabs_parsable(bool retire_tlabs) {
1091 if (UseTLAB) {
1092 CollectedHeap::ensure_parsability(retire_tlabs);
1093 }
1094 ShenandoahRetireTLABClosure cl(retire_tlabs);
1095 Threads::java_threads_do(&cl);
1096 gc_threads_do(&cl);
1097 }
1098
1099
1100 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1101 ShenandoahRootEvacuator* _rp;
1102 public:
1103
1104 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1105 AbstractGangTask("Shenandoah evacuate and update roots"),
1106 _rp(rp)
1107 {
1108 // Nothing else to do.
1109 }
1110
1111 void work(uint worker_id) {
1112 ShenandoahEvacOOMScope oom_evac_scope;
1113 ShenandoahEvacuateUpdateRootsClosure cl;
1114
1115 if (ShenandoahConcurrentEvacCodeRoots) {
1116 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1117 } else {
1118 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1119 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1120 }
1121 }
1122 };
1123
1124 class ShenandoahFixRootsTask : public AbstractGangTask {
1125 ShenandoahRootEvacuator* _rp;
1126 public:
1127
1128 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1129 AbstractGangTask("Shenandoah update roots"),
1130 _rp(rp)
1131 {
1132 // Nothing else to do.
1133 }
1134
1135 void work(uint worker_id) {
1136 ShenandoahEvacOOMScope oom_evac_scope;
1137 ShenandoahUpdateRefsClosure cl;
1138 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1139
1140 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1141 }
1142 };
1143
1144 void ShenandoahHeap::evacuate_and_update_roots() {
1145
1146 #if defined(COMPILER2) || INCLUDE_JVMCI
1147 DerivedPointerTable::clear();
1148 #endif
1149 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1150
1151 {
1152 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1153 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1154 workers()->run_task(&roots_task);
1155 }
1156
1157 #if defined(COMPILER2) || INCLUDE_JVMCI
1158 DerivedPointerTable::update_pointers();
1159 #endif
1160 if (cancelled_concgc()) {
1161 fixup_roots();
1162 }
1163 }
1164
1165 void ShenandoahHeap::fixup_roots() {
1166 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1167
1168 // If initial evacuation has been cancelled, we need to update all references
1169 // after all workers have finished. Otherwise we might run into the following problem:
1170 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1171 // GC thread 2 evacuates the same object X to to-space
1172 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1173 // clear() and update_pointers() must always be called in pairs,
1174 // cannot nest with above clear()/update_pointers().
1175 #if defined(COMPILER2) || INCLUDE_JVMCI
1176 DerivedPointerTable::clear();
1177 #endif
1178 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1179 ShenandoahFixRootsTask update_roots_task(&rp);
1180 workers()->run_task(&update_roots_task);
1181 #if defined(COMPILER2) || INCLUDE_JVMCI
1182 DerivedPointerTable::update_pointers();
1183 #endif
1184 }
1185
1186 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1187 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1188
1189 CodeBlobToOopClosure blobsCl(cl, false);
1190 CLDToOopClosure cldCl(cl);
1191
1192 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1193 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1194 }
1195
1196 bool ShenandoahHeap::supports_tlab_allocation() const {
1197 return true;
1198 }
1199
1200 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1201 return MIN2(_free_set->unsafe_peek_free(), max_tlab_size());
1202 }
1203
1204 size_t ShenandoahHeap::max_tlab_size() const {
1205 return ShenandoahHeapRegion::max_tlab_size_bytes();
1206 }
1207
1208 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1209 public:
1210 void do_thread(Thread* thread) {
1211 ShenandoahHeap* heap = ShenandoahHeap::heap();
1212 PLAB* gclab = thread->gclab();
1213 if (gclab != NULL) {
1214 if (thread->is_Java_thread()) {
1215 gclab->flush_and_retire_stats(heap->mutator_gclab_stats());
1216 } else {
1217 gclab->flush_and_retire_stats(heap->collector_gclab_stats());
1218 }
1219 }
1220 }
1221 };
1222
1223 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1224 ShenandoahAccumulateStatisticsGCLABClosure cl;
1225 Threads::java_threads_do(&cl);
1226 gc_threads_do(&cl);
1227 _mutator_gclab_stats->adjust_desired_plab_sz();
1228 _collector_gclab_stats->adjust_desired_plab_sz();
1229 }
1230
1231 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1232 return true;
1233 }
1234
1235 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1236 // Overridden to do nothing.
1237 return new_obj;
1238 }
1239
1240 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1241 return true;
1242 }
1243
1244 bool ShenandoahHeap::card_mark_must_follow_store() const {
1245 return false;
1246 }
1247
1248 void ShenandoahHeap::collect(GCCause::Cause cause) {
1249 _control_thread->handle_explicit_gc(cause);
1250 }
1251
1252 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1253 //assert(false, "Shouldn't need to do full collections");
1254 }
1255
1256 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1257 Unimplemented();
1258 return NULL;
1259
1260 }
1261
1262 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1263 return _shenandoah_policy;
1264 }
1265
1266
1267 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1268 Space* sp = heap_region_containing(addr);
1269 if (sp != NULL) {
1270 return sp->block_start(addr);
1271 }
1272 return NULL;
1273 }
1274
1275 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1276 Space* sp = heap_region_containing(addr);
1277 assert(sp != NULL, "block_size of address outside of heap");
1278 return sp->block_size(addr);
1279 }
1280
1281 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1282 Space* sp = heap_region_containing(addr);
1283 return sp->block_is_obj(addr);
1284 }
1285
1286 jlong ShenandoahHeap::millis_since_last_gc() {
1287 return 0;
1288 }
1289
1290 void ShenandoahHeap::prepare_for_verify() {
1291 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1292 make_tlabs_parsable(false);
1293 }
1294 }
1295
1296 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1297 workers()->print_worker_threads_on(st);
1298 if (ShenandoahStringDedup::is_enabled()) {
1299 ShenandoahStringDedup::print_worker_threads_on(st);
1300 }
1301 }
1302
1303 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1304 workers()->threads_do(tcl);
1305 if (ShenandoahStringDedup::is_enabled()) {
1306 ShenandoahStringDedup::threads_do(tcl);
1307 }
1308 }
1309
1310 void ShenandoahHeap::print_tracing_info() const {
1311 LogTarget(Info, gc, stats) lt;
1312 if (lt.is_enabled()) {
1313 ResourceMark rm;
1314 LogStream ls(lt);
1315
1316 phase_timings()->print_on(&ls);
1317
1318 ls.cr();
1319 ls.cr();
1320
1321 shenandoahPolicy()->print_gc_stats(&ls);
1322
1323 ls.cr();
1324 ls.cr();
1325
1326 if (ShenandoahPacing) {
1327 pacer()->print_on(&ls);
1328 }
1329
1330 ls.cr();
1331 ls.cr();
1332
1333 if (ShenandoahAllocationTrace) {
1334 assert(alloc_tracker() != NULL, "Must be");
1335 alloc_tracker()->print_on(&ls);
1336 } else {
1337 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1338 }
1339 }
1340 }
1341
1342 void ShenandoahHeap::verify(VerifyOption vo) {
1343 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1344 if (ShenandoahVerify) {
1345 verifier()->verify_generic(vo);
1346 } else {
1347 // TODO: Consider allocating verification bitmaps on demand,
1348 // and turn this on unconditionally.
1349 }
1350 }
1351 }
1352 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1353 return _free_set->capacity();
1354 }
1355
1356 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1357 private:
1358 MarkBitMap* _bitmap;
1359 Stack<oop,mtGC>* _oop_stack;
1360
1361 template <class T>
1362 void do_oop_work(T* p) {
1363 T o = oopDesc::load_heap_oop(p);
1364 if (!oopDesc::is_null(o)) {
1365 oop obj = oopDesc::decode_heap_oop_not_null(o);
1366 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1367 assert(oopDesc::is_oop(obj), "must be a valid oop");
1368 if (!_bitmap->isMarked((HeapWord*) obj)) {
1369 _bitmap->mark((HeapWord*) obj);
1370 _oop_stack->push(obj);
1371 }
1372 }
1373 }
1374 public:
1375 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1376 _bitmap(bitmap), _oop_stack(oop_stack) {}
1377 void do_oop(oop* p) { do_oop_work(p); }
1378 void do_oop(narrowOop* p) { do_oop_work(p); }
1379 };
1380
1381 /*
1382 * This is public API, used in preparation of object_iterate().
1383 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1384 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1385 * control, we call SH::make_tlabs_parsable().
1386 */
1387 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1388 // No-op.
1389 }
1390
1391 /*
1392 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1393 *
1394 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1395 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1396 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1397 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1398 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1399 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1400 * wiped the bitmap in preparation for next marking).
1401 *
1402 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1403 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1404 * is allowed to report dead objects, but is not required to do so.
1405 */
1406 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1407 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1408 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1409 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1410 return;
1411 }
1412
1413 Stack<oop,mtGC> oop_stack;
1414
1415 // First, we process all GC roots. This populates the work stack with initial objects.
1416 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1417 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1418 CLDToOopClosure clds(&oops, false);
1419 CodeBlobToOopClosure blobs(&oops, false);
1420 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1421
1422 // Work through the oop stack to traverse heap.
1423 while (! oop_stack.is_empty()) {
1424 oop obj = oop_stack.pop();
1425 assert(oopDesc::is_oop(obj), "must be a valid oop");
1426 cl->do_object(obj);
1427 obj->oop_iterate(&oops);
1428 }
1429
1430 assert(oop_stack.is_empty(), "should be empty");
1431
1432 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1433 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1434 }
1435 }
1436
1437 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1438 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1439 object_iterate(cl);
1440 }
1441
1442 // Apply blk->heap_region_do() on all committed regions in address order,
1443 // terminating the iteration early if heap_region_do() returns true.
1444 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1445 for (size_t i = 0; i < num_regions(); i++) {
1446 ShenandoahHeapRegion* current = get_region(i);
1447 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1448 continue;
1449 }
1450 if (skip_cset_regions && in_collection_set(current)) {
1451 continue;
1452 }
1453 if (blk->heap_region_do(current)) {
1454 return;
1455 }
1456 }
1457 }
1458
1459 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1460 private:
1461 ShenandoahHeap* sh;
1462 public:
1463 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1464
1465 bool heap_region_do(ShenandoahHeapRegion* r) {
1466 r->clear_live_data();
1467 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1468 return false;
1469 }
1470 };
1471
1472 void ShenandoahHeap::op_init_mark() {
1473 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1474
1475 assert(is_next_bitmap_clear(), "need clear marking bitmap");
1476
1477 if (ShenandoahVerify) {
1478 verifier()->verify_before_concmark();
1479 }
1480
1481 {
1482 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1483 accumulate_statistics_all_tlabs();
1484 }
1485
1486 set_concurrent_mark_in_progress(true);
1487 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1488 {
1489 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1490 make_tlabs_parsable(true);
1491 }
1492
1493 {
1494 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1495 ShenandoahClearLivenessClosure clc(this);
1496 heap_region_iterate(&clc);
1497 }
1498
1499 // Make above changes visible to worker threads
1500 OrderAccess::fence();
1501
1502 concurrentMark()->init_mark_roots();
1503
1504 if (UseTLAB) {
1505 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1506 resize_all_tlabs();
1507 }
1508
1509 if (ShenandoahPacing) {
1510 pacer()->setup_for_mark();
1511 }
1512 }
1513
1514 void ShenandoahHeap::op_mark() {
1515 concurrentMark()->mark_from_roots();
1516
1517 // Allocations happen during concurrent mark, record peak after the phase:
1518 shenandoahPolicy()->record_peak_occupancy();
1519 }
1520
1521 void ShenandoahHeap::op_final_mark() {
1522 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1523
1524 // It is critical that we
1525 // evacuate roots right after finishing marking, so that we don't
1526 // get unmarked objects in the roots.
1527
1528 if (! cancelled_concgc()) {
1529 concurrentMark()->finish_mark_from_roots();
1530 stop_concurrent_marking();
1531
1532 {
1533 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1534 prepare_for_concurrent_evacuation();
1535 }
1536
1537 // If collection set has candidates, start evacuation.
1538 // Otherwise, bypass the rest of the cycle.
1539 if (!collection_set()->is_empty()) {
1540 set_evacuation_in_progress(true);
1541 // From here on, we need to update references.
1542 set_has_forwarded_objects(true);
1543
1544 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1545 evacuate_and_update_roots();
1546 }
1547
1548 if (ShenandoahPacing) {
1549 pacer()->setup_for_evac();
1550 }
1551 } else {
1552 concurrentMark()->cancel();
1553 stop_concurrent_marking();
1554
1555 if (process_references()) {
1556 // Abandon reference processing right away: pre-cleaning must have failed.
1557 ReferenceProcessor *rp = ref_processor();
1558 rp->disable_discovery();
1559 rp->abandon_partial_discovery();
1560 rp->verify_no_references_recorded();
1561 }
1562 }
1563 }
1564
1565 void ShenandoahHeap::op_final_evac() {
1566 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1567
1568 accumulate_statistics_all_gclabs();
1569 set_evacuation_in_progress(false);
1570 if (ShenandoahVerify) {
1571 verifier()->verify_after_evacuation();
1572 }
1573 }
1574
1575 void ShenandoahHeap::op_evac() {
1576
1577 LogTarget(Trace, gc, region) lt_region;
1578 LogTarget(Trace, gc, cset) lt_cset;
1579
1580 if (lt_region.is_enabled()) {
1581 ResourceMark rm;
1582 LogStream ls(lt_region);
1583 ls.print_cr("All available regions:");
1584 print_heap_regions_on(&ls);
1585 }
1586
1587 if (lt_cset.is_enabled()) {
1588 ResourceMark rm;
1589 LogStream ls(lt_cset);
1590 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1591 _collection_set->print_on(&ls);
1592
1593 ls.print_cr("Free set:");
1594 _free_set->print_on(&ls);
1595 }
1596
1597 ShenandoahParallelEvacuationTask task(this, _collection_set);
1598 workers()->run_task(&task);
1599
1600 if (lt_cset.is_enabled()) {
1601 ResourceMark rm;
1602 LogStream ls(lt_cset);
1603 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1604 _collection_set->count());
1605 _collection_set->print_on(&ls);
1606
1607 ls.print_cr("After evacuation free set:");
1608 _free_set->print_on(&ls);
1609 }
1610
1611 if (lt_region.is_enabled()) {
1612 ResourceMark rm;
1613 LogStream ls(lt_region);
1614 ls.print_cr("All regions after evacuation:");
1615 print_heap_regions_on(&ls);
1616 }
1617
1618 // Allocations happen during evacuation, record peak after the phase:
1619 shenandoahPolicy()->record_peak_occupancy();
1620 }
1621
1622 void ShenandoahHeap::op_updaterefs() {
1623 update_heap_references(true);
1624
1625 // Allocations happen during update-refs, record peak after the phase:
1626 shenandoahPolicy()->record_peak_occupancy();
1627 }
1628
1629 void ShenandoahHeap::op_cleanup() {
1630 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1631 free_set()->recycle_trash();
1632
1633 // Allocations happen during cleanup, record peak after the phase:
1634 shenandoahPolicy()->record_peak_occupancy();
1635 }
1636
1637 void ShenandoahHeap::op_cleanup_bitmaps() {
1638 op_cleanup();
1639
1640 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1641 reset_next_mark_bitmap();
1642
1643 // Allocations happen during bitmap cleanup, record peak after the phase:
1644 shenandoahPolicy()->record_peak_occupancy();
1645 }
1646
1647 void ShenandoahHeap::op_cleanup_traversal() {
1648
1649 {
1650 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1651 reset_next_mark_bitmap_traversal();
1652 }
1653
1654 op_cleanup();
1655
1656 // Allocations happen during bitmap cleanup, record peak after the phase:
1657 shenandoahPolicy()->record_peak_occupancy();
1658 }
1659
1660 void ShenandoahHeap::op_preclean() {
1661 concurrentMark()->preclean_weak_refs();
1662
1663 // Allocations happen during concurrent preclean, record peak after the phase:
1664 shenandoahPolicy()->record_peak_occupancy();
1665 }
1666
1667 void ShenandoahHeap::op_init_traversal() {
1668 traversal_gc()->init_traversal_collection();
1669 }
1670
1671 void ShenandoahHeap::op_traversal() {
1672 traversal_gc()->concurrent_traversal_collection();
1673 }
1674
1675 void ShenandoahHeap::op_final_traversal() {
1676 traversal_gc()->final_traversal_collection();
1677 }
1678
1679 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1680 full_gc()->do_it(cause);
1681 if (UseTLAB) {
1682 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1683 resize_all_tlabs();
1684 }
1685 }
1686
1687 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1688 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1689 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1690 // some phase, we have to upgrade the Degenerate GC to Full GC.
1691
1692 clear_cancelled_concgc();
1693
1694 size_t used_before = used();
1695
1696 switch (point) {
1697 case _degenerated_evac:
1698 // Not possible to degenerate from here, upgrade to Full GC right away.
1699 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1700 op_degenerated_fail();
1701 return;
1702
1703 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1704 // but enters it at different points, depending on which concurrent phase had
1705 // degenerated.
1706
1707 case _degenerated_traversal:
1708 {
1709 ShenandoahHeapLocker locker(lock());
1710 collection_set()->clear_current_index();
1711 for (size_t i = 0; i < collection_set()->count(); i++) {
1712 ShenandoahHeapRegion* r = collection_set()->next();
1713 r->make_regular_bypass();
1714 }
1715 collection_set()->clear();
1716 }
1717 op_final_traversal();
1718 op_cleanup_traversal();
1719 return;
1720
1721 case _degenerated_outside_cycle:
1722 if (shenandoahPolicy()->can_do_traversal_gc()) {
1723 // Not possible to degenerate from here, upgrade to Full GC right away.
1724 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1725 op_degenerated_fail();
1726 return;
1727 }
1728 op_init_mark();
1729 if (cancelled_concgc()) {
1730 op_degenerated_fail();
1731 return;
1732 }
1733
1734 case _degenerated_mark:
1735 op_final_mark();
1736 if (cancelled_concgc()) {
1737 op_degenerated_fail();
1738 return;
1739 }
1740
1741 op_cleanup();
1742
1743 // If heuristics thinks we should do the cycle, this flag would be set,
1744 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1745 if (is_evacuation_in_progress()) {
1746 op_evac();
1747 if (cancelled_concgc()) {
1748 op_degenerated_fail();
1749 return;
1750 }
1751 }
1752
1753 // If heuristics thinks we should do the cycle, this flag would be set,
1754 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1755 if (has_forwarded_objects()) {
1756 op_init_updaterefs();
1757 if (cancelled_concgc()) {
1758 op_degenerated_fail();
1759 return;
1760 }
1761 }
1762
1763 case _degenerated_updaterefs:
1764 if (has_forwarded_objects()) {
1765 op_final_updaterefs();
1766 if (cancelled_concgc()) {
1767 op_degenerated_fail();
1768 return;
1769 }
1770 }
1771
1772 op_cleanup_bitmaps();
1773 break;
1774
1775 default:
1776 ShouldNotReachHere();
1777 }
1778
1779 if (ShenandoahVerify) {
1780 verifier()->verify_after_degenerated();
1781 }
1782
1783 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1784 // because that probably means the heap is overloaded and/or fragmented.
1785 size_t used_after = used();
1786 size_t difference = (used_before > used_after) ? used_before - used_after : 0;
1787 if (difference < ShenandoahHeapRegion::region_size_words()) {
1788 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1789 op_degenerated_futile();
1790 }
1791 }
1792
1793 void ShenandoahHeap::op_degenerated_fail() {
1794 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1795 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1796 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1797 }
1798
1799 void ShenandoahHeap::op_degenerated_futile() {
1800 log_info(gc)("Degenerated GC had not reclaimed enough, upgrading to Full GC");
1801 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1802 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1803 }
1804
1805 void ShenandoahHeap::swap_mark_bitmaps() {
1806 // Swap bitmaps.
1807 MarkBitMap* tmp1 = _complete_mark_bit_map;
1808 _complete_mark_bit_map = _next_mark_bit_map;
1809 _next_mark_bit_map = tmp1;
1810
1811 // Swap top-at-mark-start pointers
1812 HeapWord** tmp2 = _complete_top_at_mark_starts;
1813 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1814 _next_top_at_mark_starts = tmp2;
1815
1816 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1817 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1818 _next_top_at_mark_starts_base = tmp3;
1819 }
1820
1821
1822 void ShenandoahHeap::stop_concurrent_marking() {
1823 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1824 if (! cancelled_concgc()) {
1825 // If we needed to update refs, and concurrent marking has been cancelled,
1826 // we need to finish updating references.
1827 set_has_forwarded_objects(false);
1828 swap_mark_bitmaps();
1829 }
1830 set_concurrent_mark_in_progress(false);
1831
1832 LogTarget(Trace, gc, region) lt;
1833 if (lt.is_enabled()) {
1834 ResourceMark rm;
1835 LogStream ls(lt);
1836 ls.print_cr("Regions at stopping the concurrent mark:");
1837 print_heap_regions_on(&ls);
1838 }
1839 }
1840
1841 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1842 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1843 _gc_state.set_cond(mask, value);
1844 JavaThread::set_gc_state_all_threads(_gc_state.raw_value());
1845 }
1846
1847 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1848 set_gc_state_mask(MARKING, in_progress);
1849 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1850 }
1851
1852 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1853 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1854 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1855 }
1856
1857 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1858 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1859 set_gc_state_mask(EVACUATION, in_progress);
1860 }
1861
1862 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1863 // Initialize Brooks pointer for the next object
1864 HeapWord* result = obj + BrooksPointer::word_size();
1865 BrooksPointer::initialize(oop(result));
1866 return result;
1867 }
1868
1869 uint ShenandoahHeap::oop_extra_words() {
1870 return BrooksPointer::word_size();
1871 }
1872
1873 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1874 _heap(ShenandoahHeap::heap_no_check()) {
1875 }
1876
1877 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1878 _heap(ShenandoahHeap::heap_no_check()) {
1879 }
1880
1881 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1882 if (oopDesc::is_null(obj)) {
1883 return false;
1884 }
1885 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1886 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_mark_in_progress() || _heap->is_concurrent_traversal_in_progress())
1887 return _heap->is_marked_next(obj);
1888 }
1889
1890 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1891 if (oopDesc::is_null(obj)) {
1892 return false;
1893 }
1894 shenandoah_assert_not_forwarded(NULL, obj);
1895 return _heap->is_marked_next(obj);
1896 }
1897
1898 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1899 return has_forwarded_objects() ?
1900 (BoolObjectClosure*) &_forwarded_is_alive :
1901 (BoolObjectClosure*) &_is_alive;
1902 }
1903
1904 void ShenandoahHeap::ref_processing_init() {
1905 MemRegion mr = reserved_region();
1906
1907 _forwarded_is_alive.init(this);
1908 _is_alive.init(this);
1909 assert(_max_workers > 0, "Sanity");
1910
1911 _ref_processor =
1912 new ReferenceProcessor(mr, // span
1913 ParallelRefProcEnabled, // MT processing
1914 _max_workers, // Degree of MT processing
1915 true, // MT discovery
1916 _max_workers, // Degree of MT discovery
1917 false, // Reference discovery is not atomic
1918 NULL); // No closure, should be installed before use
1919
1920 shenandoah_assert_rp_isalive_not_installed();
1921 }
1922
1923
1924 GCTracer* ShenandoahHeap::tracer() {
1925 return shenandoahPolicy()->tracer();
1926 }
1927
1928 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1929 return _free_set->used();
1930 }
1931
1932 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1933 if (try_cancel_concgc()) {
1934 FormatBuffer<> msg("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1935 log_info(gc)("%s", msg.buffer());
1936 Events::log(Thread::current(), "%s", msg.buffer());
1937 }
1938 }
1939
1940 uint ShenandoahHeap::max_workers() {
1941 return _max_workers;
1942 }
1943
1944 void ShenandoahHeap::stop() {
1945 // The shutdown sequence should be able to terminate when GC is running.
1946
1947 // Step 0. Notify policy to disable event recording.
1948 _shenandoah_policy->record_shutdown();
1949
1950 // Step 1. Notify control thread that we are in shutdown.
1951 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1952 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1953 _control_thread->prepare_for_graceful_shutdown();
1954
1955 // Step 2. Notify GC workers that we are cancelling GC.
1956 cancel_concgc(GCCause::_shenandoah_stop_vm);
1957
1958 // Step 3. Wait until GC worker exits normally.
1959 _control_thread->stop();
1960
1961 // Step 4. Stop String Dedup thread if it is active
1962 if (ShenandoahStringDedup::is_enabled()) {
1963 ShenandoahStringDedup::stop();
1964 }
1965 }
1966
1967 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1968 ShenandoahPhaseTimings::Phase phase_root =
1969 full_gc ?
1970 ShenandoahPhaseTimings::full_gc_purge :
1971 ShenandoahPhaseTimings::purge;
1972
1973 ShenandoahPhaseTimings::Phase phase_unload =
1974 full_gc ?
1975 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1976 ShenandoahPhaseTimings::purge_class_unload;
1977
1978 ShenandoahPhaseTimings::Phase phase_cldg =
1979 full_gc ?
1980 ShenandoahPhaseTimings::full_gc_purge_cldg :
1981 ShenandoahPhaseTimings::purge_cldg;
1982
1983 ShenandoahPhaseTimings::Phase phase_par =
1984 full_gc ?
1985 ShenandoahPhaseTimings::full_gc_purge_par :
1986 ShenandoahPhaseTimings::purge_par;
1987
1988 ShenandoahPhaseTimings::Phase phase_par_classes =
1989 full_gc ?
1990 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1991 ShenandoahPhaseTimings::purge_par_classes;
1992
1993 ShenandoahPhaseTimings::Phase phase_par_codecache =
1994 full_gc ?
1995 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1996 ShenandoahPhaseTimings::purge_par_codecache;
1997
1998 ShenandoahPhaseTimings::Phase phase_par_rmt =
1999 full_gc ?
2000 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
2001 ShenandoahPhaseTimings::purge_par_rmt;
2002
2003 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2004 full_gc ?
2005 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2006 ShenandoahPhaseTimings::purge_par_symbstring;
2007
2008 ShenandoahPhaseTimings::Phase phase_par_sync =
2009 full_gc ?
2010 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2011 ShenandoahPhaseTimings::purge_par_sync;
2012
2013 ShenandoahGCPhase root_phase(phase_root);
2014
2015 BoolObjectClosure* is_alive = is_alive_closure();
2016
2017 bool purged_class;
2018
2019 // Unload classes and purge SystemDictionary.
2020 {
2021 ShenandoahGCPhase phase(phase_unload);
2022 purged_class = SystemDictionary::do_unloading(is_alive,
2023 gc_timer(),
2024 false /* defer cleaning */);
2025 }
2026
2027 {
2028 ShenandoahGCPhase phase(phase_par);
2029 uint active = _workers->active_workers();
2030 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
2031 _workers->run_task(&unlink_task);
2032
2033 ShenandoahPhaseTimings* p = phase_timings();
2034 ParallelCleaningTimes times = unlink_task.times();
2035
2036 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2037 // by active workers to get average time per worker, that would add up to wall time.
2038 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2039 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2040 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
2041 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2042 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2043 }
2044
2045 if (ShenandoahStringDedup::is_enabled()) {
2046 ShenandoahPhaseTimings::Phase phase_par_string_dedup =
2047 full_gc ?
2048 ShenandoahPhaseTimings::full_gc_purge_par_string_dedup :
2049 ShenandoahPhaseTimings::purge_par_string_dedup;
2050 ShenandoahGCPhase phase(phase_par_string_dedup);
2051 ShenandoahStringDedup::parallel_cleanup();
2052 }
2053
2054
2055 {
2056 ShenandoahGCPhase phase(phase_cldg);
2057 ClassLoaderDataGraph::purge();
2058 }
2059 }
2060
2061 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2062 set_gc_state_mask(HAS_FORWARDED, cond);
2063 }
2064
2065 void ShenandoahHeap::set_process_references(bool pr) {
2066 _process_references.set_cond(pr);
2067 }
2068
2069 void ShenandoahHeap::set_unload_classes(bool uc) {
2070 _unload_classes.set_cond(uc);
2071 }
2072
2073 bool ShenandoahHeap::process_references() const {
2074 return _process_references.is_set();
2075 }
2076
2077 bool ShenandoahHeap::unload_classes() const {
2078 return _unload_classes.is_set();
2079 }
2080
2081 //fixme this should be in heapregionset
2082 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2083 size_t region_idx = r->region_number() + 1;
2084 ShenandoahHeapRegion* next = get_region(region_idx);
2085 guarantee(next->region_number() == region_idx, "region number must match");
2086 while (next->is_humongous()) {
2087 region_idx = next->region_number() + 1;
2088 next = get_region(region_idx);
2089 guarantee(next->region_number() == region_idx, "region number must match");
2090 }
2091 return next;
2092 }
2093
2094 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2095 return _monitoring_support;
2096 }
2097
2098 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
2099 return _complete_mark_bit_map;
2100 }
2101
2102 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
2103 return _next_mark_bit_map;
2104 }
2105
2106 address ShenandoahHeap::in_cset_fast_test_addr() {
2107 ShenandoahHeap* heap = ShenandoahHeap::heap();
2108 assert(heap->collection_set() != NULL, "Sanity");
2109 return (address) heap->collection_set()->biased_map_address();
2110 }
2111
2112 address ShenandoahHeap::cancelled_concgc_addr() {
2113 return (address) ShenandoahHeap::heap()->_cancelled_concgc.addr_of();
2114 }
2115
2116 address ShenandoahHeap::gc_state_addr() {
2117 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2118 }
2119
2120 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2121 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2122 }
2123
2124 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2125 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2126 }
2127
2128 ShenandoahPacer* ShenandoahHeap::pacer() const {
2129 assert (_pacer != NULL, "sanity");
2130 return _pacer;
2131 }
2132
2133 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2134 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2135 _next_top_at_mark_starts[index] = addr;
2136 }
2137
2138 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2139 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2140 return _next_top_at_mark_starts[index];
2141 }
2142
2143 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2144 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2145 _complete_top_at_mark_starts[index] = addr;
2146 }
2147
2148 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2149 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2150 return _complete_top_at_mark_starts[index];
2151 }
2152
2153 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2154 _degenerated_gc_in_progress.set_cond(in_progress);
2155 }
2156
2157 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2158 _full_gc_in_progress.set_cond(in_progress);
2159 }
2160
2161 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2162 assert (is_full_gc_in_progress(), "should be");
2163 _full_gc_move_in_progress.set_cond(in_progress);
2164 }
2165
2166 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2167 set_gc_state_mask(UPDATEREFS, in_progress);
2168 }
2169
2170 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2171 ShenandoahCodeRoots::add_nmethod(nm);
2172 }
2173
2174 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2175 ShenandoahCodeRoots::remove_nmethod(nm);
2176 }
2177
2178 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2179 o = BarrierSet::barrier_set()->write_barrier(o);
2180 ShenandoahHeapLocker locker(lock());
2181 heap_region_containing(o)->make_pinned();
2182 return o;
2183 }
2184
2185 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2186 o = BarrierSet::barrier_set()->read_barrier(o);
2187 ShenandoahHeapLocker locker(lock());
2188 heap_region_containing(o)->make_unpinned();
2189 }
2190
2191 GCTimer* ShenandoahHeap::gc_timer() const {
2192 return _gc_timer;
2193 }
2194
2195 #ifdef ASSERT
2196 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2197 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2198
2199 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2200 if (UseDynamicNumberOfGCThreads ||
2201 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2202 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2203 } else {
2204 // Use ParallelGCThreads inside safepoints
2205 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2206 }
2207 } else {
2208 if (UseDynamicNumberOfGCThreads ||
2209 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2210 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2211 } else {
2212 // Use ConcGCThreads outside safepoints
2213 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2214 }
2215 }
2216 }
2217 #endif
2218
2219 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
2220 return _connection_matrix;
2221 }
2222
2223 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2224 return _traversal_gc;
2225 }
2226
2227 ShenandoahVerifier* ShenandoahHeap::verifier() {
2228 guarantee(ShenandoahVerify, "Should be enabled");
2229 assert (_verifier != NULL, "sanity");
2230 return _verifier;
2231 }
2232
2233 template<class T>
2234 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2235 private:
2236 T cl;
2237 ShenandoahHeap* _heap;
2238 ShenandoahRegionIterator* _regions;
2239 bool _concurrent;
2240 public:
2241 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2242 AbstractGangTask("Concurrent Update References Task"),
2243 cl(T()),
2244 _heap(ShenandoahHeap::heap()),
2245 _regions(regions),
2246 _concurrent(concurrent) {
2247 }
2248
2249 void work(uint worker_id) {
2250 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2251 ShenandoahHeapRegion* r = _regions->next();
2252 while (r != NULL) {
2253 if (_heap->in_collection_set(r)) {
2254 HeapWord* bottom = r->bottom();
2255 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2256 if (top > bottom) {
2257 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2258 }
2259 } else {
2260 if (r->is_active()) {
2261 _heap->marked_object_oop_safe_iterate(r, &cl);
2262 if (ShenandoahPacing) {
2263 _heap->pacer()->report_updaterefs(r->get_live_data_words());
2264 }
2265 }
2266 }
2267 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
2268 return;
2269 }
2270 r = _regions->next();
2271 }
2272 }
2273 };
2274
2275 void ShenandoahHeap::update_heap_references(bool concurrent) {
2276 if (UseShenandoahMatrix) {
2277 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(&_update_refs_iterator, concurrent);
2278 workers()->run_task(&task);
2279 } else {
2280 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2281 workers()->run_task(&task);
2282 }
2283 }
2284
2285 void ShenandoahHeap::op_init_updaterefs() {
2286 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2287
2288 if (ShenandoahVerify) {
2289 verifier()->verify_before_updaterefs();
2290 }
2291
2292 accumulate_statistics_all_gclabs();
2293 set_evacuation_in_progress(false);
2294 set_update_refs_in_progress(true);
2295 make_tlabs_parsable(true);
2296 if (UseShenandoahMatrix) {
2297 connection_matrix()->clear_all();
2298 }
2299 for (uint i = 0; i < num_regions(); i++) {
2300 ShenandoahHeapRegion* r = get_region(i);
2301 r->set_concurrent_iteration_safe_limit(r->top());
2302 }
2303
2304 // Reset iterator.
2305 _update_refs_iterator = ShenandoahRegionIterator();
2306
2307 if (ShenandoahPacing) {
2308 pacer()->setup_for_updaterefs();
2309 }
2310 }
2311
2312 void ShenandoahHeap::op_final_updaterefs() {
2313 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2314
2315 // Check if there is left-over work, and finish it
2316 if (_update_refs_iterator.has_next()) {
2317 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2318
2319 // Finish updating references where we left off.
2320 clear_cancelled_concgc();
2321 update_heap_references(false);
2322 }
2323
2324 // Clear cancelled conc GC, if set. On cancellation path, the block before would handle
2325 // everything. On degenerated paths, cancelled gc would not be set anyway.
2326 if (cancelled_concgc()) {
2327 clear_cancelled_concgc();
2328 }
2329 assert(!cancelled_concgc(), "Should have been done right before");
2330
2331 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2332
2333 // Allocations might have happened before we STWed here, record peak:
2334 shenandoahPolicy()->record_peak_occupancy();
2335
2336 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2337
2338 trash_cset_regions();
2339 set_has_forwarded_objects(false);
2340
2341 if (ShenandoahVerify) {
2342 verifier()->verify_after_updaterefs();
2343 }
2344
2345 {
2346 ShenandoahHeapLocker locker(lock());
2347 _free_set->rebuild();
2348 }
2349
2350 set_update_refs_in_progress(false);
2351 }
2352
2353 void ShenandoahHeap::set_alloc_seq_gc_start() {
2354 // Take next number, the start seq number is inclusive
2355 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2356 }
2357
2358 void ShenandoahHeap::set_alloc_seq_gc_end() {
2359 // Take current number, the end seq number is also inclusive
2360 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2361 }
2362
2363
2364 #ifdef ASSERT
2365 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2366 _lock.assert_owned_by_current_thread();
2367 }
2368
2369 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2370 _lock.assert_not_owned_by_current_thread();
2371 }
2372
2373 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2374 _lock.assert_owned_by_current_thread_or_safepoint();
2375 }
2376 #endif
2377
2378 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2379 print_on(st);
2380 print_heap_regions_on(st);
2381 }
2382
2383 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2384 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2385
2386 size_t regions_from = _bitmap_regions_per_slice * slice;
2387 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2388 for (size_t g = regions_from; g < regions_to; g++) {
2389 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2390 if (skip_self && g == r->region_number()) continue;
2391 if (get_region(g)->is_committed()) {
2392 return true;
2393 }
2394 }
2395 return false;
2396 }
2397
2398 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2399 assert_heaplock_owned_by_current_thread();
2400
2401 if (is_bitmap_slice_committed(r, true)) {
2402 // Some other region from the group is already committed, meaning the bitmap
2403 // slice is already committed, we exit right away.
2404 return true;
2405 }
2406
2407 // Commit the bitmap slice:
2408 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2409 size_t off = _bitmap_bytes_per_slice * slice;
2410 size_t len = _bitmap_bytes_per_slice;
2411 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2412 return false;
2413 }
2414 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2415 return false;
2416 }
2417 return true;
2418 }
2419
2420 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2421 assert_heaplock_owned_by_current_thread();
2422
2423 if (is_bitmap_slice_committed(r, true)) {
2424 // Some other region from the group is still committed, meaning the bitmap
2425 // slice is should stay committed, exit right away.
2426 return true;
2427 }
2428
2429 // Uncommit the bitmap slice:
2430 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2431 size_t off = _bitmap_bytes_per_slice * slice;
2432 size_t len = _bitmap_bytes_per_slice;
2433 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2434 return false;
2435 }
2436 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2437 return false;
2438 }
2439 return true;
2440 }
2441
2442 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2443 assert_heaplock_owned_by_current_thread();
2444 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2445
2446 if (is_bitmap_slice_committed(r, true)) {
2447 // Some other region from the group is still committed, meaning the bitmap
2448 // slice is should stay committed, exit right away.
2449 return true;
2450 }
2451
2452 // Idle the bitmap slice:
2453 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2454 size_t off = _bitmap_bytes_per_slice * slice;
2455 size_t len = _bitmap_bytes_per_slice;
2456 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2457 return false;
2458 }
2459 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2460 return false;
2461 }
2462 return true;
2463 }
2464
2465 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2466 assert_heaplock_owned_by_current_thread();
2467 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2468 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2469 size_t off = _bitmap_bytes_per_slice * slice;
2470 size_t len = _bitmap_bytes_per_slice;
2471 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2472 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2473 }
2474
2475 void ShenandoahHeap::safepoint_synchronize_begin() {
2476 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2477 SuspendibleThreadSet::synchronize();
2478 }
2479 }
2480
2481 void ShenandoahHeap::safepoint_synchronize_end() {
2482 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2483 SuspendibleThreadSet::desynchronize();
2484 }
2485 }
2486
2487 void ShenandoahHeap::vmop_entry_init_mark() {
2488 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2489 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2490 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2491
2492 try_inject_alloc_failure();
2493 VM_ShenandoahInitMark op;
2494 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2495 }
2496
2497 void ShenandoahHeap::vmop_entry_final_mark() {
2498 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2499 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2500 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2501
2502 try_inject_alloc_failure();
2503 VM_ShenandoahFinalMarkStartEvac op;
2504 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2505 }
2506
2507 void ShenandoahHeap::vmop_entry_final_evac() {
2508 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2509 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2510 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2511
2512 VM_ShenandoahFinalEvac op;
2513 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2514 }
2515
2516 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2517 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2518 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2519 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2520
2521 try_inject_alloc_failure();
2522 VM_ShenandoahInitUpdateRefs op;
2523 VMThread::execute(&op);
2524 }
2525
2526 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2527 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2528 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2529 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2530
2531 try_inject_alloc_failure();
2532 VM_ShenandoahFinalUpdateRefs op;
2533 VMThread::execute(&op);
2534 }
2535
2536 void ShenandoahHeap::vmop_entry_init_traversal() {
2537 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2538 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2539 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2540
2541 try_inject_alloc_failure();
2542 VM_ShenandoahInitTraversalGC op;
2543 VMThread::execute(&op);
2544 }
2545
2546 void ShenandoahHeap::vmop_entry_final_traversal() {
2547 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2548 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2549 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2550
2551 try_inject_alloc_failure();
2552 VM_ShenandoahFinalTraversalGC op;
2553 VMThread::execute(&op);
2554 }
2555
2556 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2557 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2558 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2559 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2560
2561 try_inject_alloc_failure();
2562 VM_ShenandoahFullGC op(cause);
2563 VMThread::execute(&op);
2564 }
2565
2566 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2567 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2568 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2569 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2570
2571 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2572 VMThread::execute(°enerated_gc);
2573 }
2574
2575 void ShenandoahHeap::entry_init_mark() {
2576 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2577 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2578
2579 FormatBuffer<> msg("Pause Init Mark%s%s%s",
2580 has_forwarded_objects() ? " (update refs)" : "",
2581 process_references() ? " (process refs)" : "",
2582 unload_classes() ? " (unload classes)" : "");
2583 GCTraceTime(Info, gc) time(msg, gc_timer());
2584 EventMark em("%s", msg.buffer());
2585
2586 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_init_marking());
2587
2588 op_init_mark();
2589 }
2590
2591 void ShenandoahHeap::entry_final_mark() {
2592 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2593 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2594
2595 FormatBuffer<> msg("Pause Final Mark%s%s%s",
2596 has_forwarded_objects() ? " (update refs)" : "",
2597 process_references() ? " (process refs)" : "",
2598 unload_classes() ? " (unload classes)" : "");
2599 GCTraceTime(Info, gc) time(msg, gc_timer());
2600 EventMark em("%s", msg.buffer());
2601
2602 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_marking());
2603
2604 op_final_mark();
2605 }
2606
2607 void ShenandoahHeap::entry_final_evac() {
2608 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2609 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2610
2611 FormatBuffer<> msg("Pause Final Evac");
2612 GCTraceTime(Info, gc) time(msg, gc_timer());
2613 EventMark em("%s", msg.buffer());
2614
2615 op_final_evac();
2616 }
2617
2618 void ShenandoahHeap::entry_init_updaterefs() {
2619 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2620 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2621
2622 static const char* msg = "Pause Init Update Refs";
2623 GCTraceTime(Info, gc) time(msg, gc_timer());
2624 EventMark em("%s", msg);
2625
2626 // No workers used in this phase, no setup required
2627
2628 op_init_updaterefs();
2629 }
2630
2631 void ShenandoahHeap::entry_final_updaterefs() {
2632 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2633 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2634
2635 static const char* msg = "Pause Final Update Refs";
2636 GCTraceTime(Info, gc) time(msg, gc_timer());
2637 EventMark em("%s", msg);
2638
2639 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_update_ref());
2640
2641 op_final_updaterefs();
2642 }
2643
2644 void ShenandoahHeap::entry_init_traversal() {
2645 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2646 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2647
2648 static const char* msg = "Pause Init Traversal";
2649 GCTraceTime(Info, gc) time(msg, gc_timer());
2650 EventMark em("%s", msg);
2651
2652 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2653
2654 op_init_traversal();
2655 }
2656
2657 void ShenandoahHeap::entry_final_traversal() {
2658 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2659 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2660
2661 static const char* msg = "Pause Final Traversal";
2662 GCTraceTime(Info, gc) time(msg, gc_timer());
2663 EventMark em("%s", msg);
2664
2665 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2666
2667 op_final_traversal();
2668 }
2669
2670 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2671 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2672 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2673
2674 static const char* msg = "Pause Full";
2675 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2676 EventMark em("%s", msg);
2677
2678 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_fullgc());
2679
2680 op_full(cause);
2681 }
2682
2683 void ShenandoahHeap::entry_degenerated(int point) {
2684 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2685 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2686
2687 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2688 FormatBuffer<> msg("Pause Degenerated GC (%s)", degen_point_to_string(dpoint));
2689 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2690 EventMark em("%s", msg.buffer());
2691
2692 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated());
2693
2694 set_degenerated_gc_in_progress(true);
2695 op_degenerated(dpoint);
2696 set_degenerated_gc_in_progress(false);
2697 }
2698
2699 void ShenandoahHeap::entry_mark() {
2700 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2701
2702 FormatBuffer<> msg("Concurrent marking%s%s%s",
2703 has_forwarded_objects() ? " (update refs)" : "",
2704 process_references() ? " (process refs)" : "",
2705 unload_classes() ? " (unload classes)" : "");
2706 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2707 EventMark em("%s", msg.buffer());
2708
2709 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_marking());
2710
2711 try_inject_alloc_failure();
2712 op_mark();
2713 }
2714
2715 void ShenandoahHeap::entry_evac() {
2716 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2717 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2718
2719 static const char* msg = "Concurrent evacuation";
2720 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2721 EventMark em("%s", msg);
2722
2723 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_evac());
2724
2725 try_inject_alloc_failure();
2726 op_evac();
2727 }
2728
2729 void ShenandoahHeap::entry_updaterefs() {
2730 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2731
2732 static const char* msg = "Concurrent update references";
2733 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2734 EventMark em("%s", msg);
2735
2736 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref());
2737
2738 try_inject_alloc_failure();
2739 op_updaterefs();
2740 }
2741 void ShenandoahHeap::entry_cleanup() {
2742 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2743
2744 static const char* msg = "Concurrent cleanup";
2745 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2746 EventMark em("%s", msg);
2747
2748 // This phase does not use workers, no need for setup
2749
2750 try_inject_alloc_failure();
2751 op_cleanup();
2752 }
2753
2754 void ShenandoahHeap::entry_cleanup_traversal() {
2755 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2756
2757 static const char* msg = "Concurrent cleanup";
2758 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2759 EventMark em("%s", msg);
2760
2761 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2762
2763 try_inject_alloc_failure();
2764 op_cleanup_traversal();
2765 }
2766
2767 void ShenandoahHeap::entry_cleanup_bitmaps() {
2768 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2769
2770 static const char* msg = "Concurrent cleanup";
2771 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2772 EventMark em("%s", msg);
2773
2774 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup());
2775
2776 try_inject_alloc_failure();
2777 op_cleanup_bitmaps();
2778 }
2779
2780 void ShenandoahHeap::entry_preclean() {
2781 if (ShenandoahPreclean && process_references()) {
2782 static const char* msg = "Concurrent precleaning";
2783 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2784 EventMark em("%s", msg);
2785
2786 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2787
2788 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_preclean());
2789
2790 try_inject_alloc_failure();
2791 op_preclean();
2792 }
2793 }
2794
2795 void ShenandoahHeap::entry_traversal() {
2796 static const char* msg = "Concurrent traversal";
2797 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2798 EventMark em("%s", msg);
2799
2800 TraceCollectorStats tcs(is_minor_gc() ? monitoring_support()->partial_collection_counters()
2801 : monitoring_support()->concurrent_collection_counters());
2802
2803 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2804
2805 try_inject_alloc_failure();
2806 op_traversal();
2807 }
2808
2809 void ShenandoahHeap::try_inject_alloc_failure() {
2810 if (ShenandoahAllocFailureALot && !cancelled_concgc() && ((os::random() % 1000) > 950)) {
2811 _inject_alloc_failure.set();
2812 os::naked_short_sleep(1);
2813 if (cancelled_concgc()) {
2814 log_info(gc)("Allocation failure was successfully injected");
2815 }
2816 }
2817 }
2818
2819 bool ShenandoahHeap::should_inject_alloc_failure() {
2820 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2821 }
2822
2823 void ShenandoahHeap::initialize_serviceability() {
2824 _memory_pool = new ShenandoahMemoryPool(this);
2825 _cycle_memory_manager.add_pool(_memory_pool);
2826 _stw_memory_manager.add_pool(_memory_pool);
2827 }
2828
2829 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2830 GrowableArray<GCMemoryManager*> memory_managers(2);
2831 memory_managers.append(&_cycle_memory_manager);
2832 memory_managers.append(&_stw_memory_manager);
2833 return memory_managers;
2834 }
2835
2836 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2837 GrowableArray<MemoryPool*> memory_pools(1);
2838 memory_pools.append(_memory_pool);
2839 return memory_pools;
2840 }
2841
2842 void ShenandoahHeap::enter_evacuation() {
2843 _oom_evac_handler.enter_evacuation();
2844 }
2845
2846 void ShenandoahHeap::leave_evacuation() {
2847 _oom_evac_handler.leave_evacuation();
2848 }
2849
2850 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2851 _index(0),
2852 _heap(ShenandoahHeap::heap()) {}
2853
2854 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2855 _index(0),
2856 _heap(heap) {}
2857
2858 ShenandoahRegionIterator& ShenandoahRegionIterator::operator=(const ShenandoahRegionIterator& o) {
2859 _index = o._index;
2860 assert(_heap == o._heap, "must be same");
2861 return *this;
2862 }
2863
2864 bool ShenandoahRegionIterator::has_next() const {
2865 return _index < _heap->num_regions();
2866 }
2867
2868 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
2869 ShenandoahRegionIterator regions;
2870 ShenandoahHeapRegion* r = regions.next();
2871 while (r != NULL) {
2872 if (cl.heap_region_do(r)) {
2873 break;
2874 }
2875 r = regions.next();
2876 }
2877 }
2878
2879 bool ShenandoahHeap::is_minor_gc() const {
2880 return _gc_cycle_mode.get() == MINOR;
2881 }
2882
2883 bool ShenandoahHeap::is_major_gc() const {
2884 return _gc_cycle_mode.get() == MAJOR;
2885 }
2886
2887 void ShenandoahHeap::set_cycle_mode(GCCycleMode gc_cycle_mode) {
2888 _gc_cycle_mode.set(gc_cycle_mode);
2889 }
2890
2891 char ShenandoahHeap::gc_state() {
2892 return _gc_state.raw_value();
2893 }
2894
2895 void ShenandoahHeap::initialize_gclab(Thread* thread) {
2896 if (thread->is_Java_thread()) {
2897 thread->set_gclab(new PLAB(OldPLABSize));
2898 } else {
2899 thread->set_gclab(new PLAB(YoungPLABSize));
2900 }
2901 }
2902
2903 void ShenandoahHeap::finalize_mutator_gclab(Thread* thread) {
2904 thread->gclab()->flush_and_retire_stats(ShenandoahHeap::heap()->mutator_gclab_stats());
2905 delete thread->gclab();
2906 thread->set_gclab(NULL);
2907 }