1 /*
2 * Copyright (c) 2013, 2017, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/parallelCleaning.hpp"
30
31 #include "gc/shenandoah/brooksPointer.hpp"
32 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
33 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentThread.hpp"
39 #include "gc/shenandoah/shenandoahFreeSet.hpp"
40 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
41 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
42 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
44 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
45 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
46 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
47 #include "gc/shenandoah/shenandoahPartialGC.hpp"
48 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
49 #include "gc/shenandoah/shenandoahStringDedup.hpp"
50 #include "gc/shenandoah/shenandoahUtils.hpp"
51 #include "gc/shenandoah/shenandoahVerifier.hpp"
52 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
53 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
54
55 #include "runtime/vmThread.hpp"
56 #include "services/mallocTracker.hpp"
57
58 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
59
60 #ifdef ASSERT
61 template <class T>
62 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
63 T o = oopDesc::load_heap_oop(p);
64 if (! oopDesc::is_null(o)) {
65 oop obj = oopDesc::decode_heap_oop_not_null(o);
66 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
67 "need to-space object here obj: "PTR_FORMAT" , rb(obj): "PTR_FORMAT", p: "PTR_FORMAT,
68 p2i(obj), p2i(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), p2i(p));
69 }
70 }
71
72 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
73 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
74 #endif
75
76 const char* ShenandoahHeap::name() const {
77 return "Shenandoah";
78 }
79
80 class ShenandoahPretouchTask : public AbstractGangTask {
81 private:
82 ShenandoahHeapRegionSet* _regions;
83 const size_t _bitmap_size;
84 const size_t _page_size;
85 char* _bitmap0_base;
86 char* _bitmap1_base;
87 public:
88 ShenandoahPretouchTask(ShenandoahHeapRegionSet* regions,
89 char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
90 size_t page_size) :
91 AbstractGangTask("Shenandoah PreTouch",
92 Universe::is_fully_initialized() ? GCId::current_raw() :
93 // During VM initialization there is
94 // no GC cycle that this task can be
95 // associated with.
96 GCId::undefined()),
97 _bitmap0_base(bitmap0_base),
98 _bitmap1_base(bitmap1_base),
99 _regions(regions),
100 _bitmap_size(bitmap_size),
101 _page_size(page_size) {
102 _regions->clear_current_index();
103 };
104
105 virtual void work(uint worker_id) {
106 ShenandoahHeapRegion* r = _regions->claim_next();
107 while (r != NULL) {
108 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
109 r->region_number(), p2i(r->bottom()), p2i(r->end()));
110 os::pretouch_memory(r->bottom(), r->end(), _page_size);
111
112 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
113 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
114 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
115
116 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
117 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
118 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
119
120 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
121 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
122 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
123
124 r = _regions->claim_next();
125 }
126 }
127 };
128
129 jint ShenandoahHeap::initialize() {
130 CollectedHeap::pre_initialize();
131
132 BrooksPointer::initial_checks();
133
134 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
135 size_t max_byte_size = collector_policy()->max_heap_byte_size();
136 size_t heap_alignment = collector_policy()->heap_alignment();
137
138 if (ShenandoahAlwaysPreTouch) {
139 // Enabled pre-touch means the entire heap is committed right away.
140 init_byte_size = max_byte_size;
141 }
142
143 Universe::check_alignment(max_byte_size,
144 ShenandoahHeapRegion::region_size_bytes(),
145 "shenandoah heap");
146 Universe::check_alignment(init_byte_size,
147 ShenandoahHeapRegion::region_size_bytes(),
148 "shenandoah heap");
149
150 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
151 heap_alignment);
152 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
153
154 set_barrier_set(new ShenandoahBarrierSet(this));
155 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
156
157 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
158 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
159 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
160 _committed = _initial_size;
161
162 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
163 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
164 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
165 }
166
167 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
168
169 _ordered_regions = new ShenandoahHeapRegionSet(_num_regions);
170 _free_regions = new ShenandoahFreeSet(_ordered_regions, _num_regions);
171
172 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
173
174 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
175 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
176 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
177
178 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
179 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
180 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
181
182 {
183 ShenandoahHeapLocker locker(lock());
184 for (size_t i = 0; i < _num_regions; i++) {
185 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
186 (HeapWord*) pgc_rs.base() + reg_size_words * i,
187 reg_size_words,
188 i,
189 i < num_committed_regions);
190
191 _complete_top_at_mark_starts_base[i] = r->bottom();
192 _next_top_at_mark_starts_base[i] = r->bottom();
193
194 // Add to ordered regions first.
195 // We use the active size of ordered regions as the number of active regions in heap,
196 // free set and collection set use the number to assert the correctness of incoming regions.
197 _ordered_regions->add_region(r);
198 _free_regions->add_region(r);
199 assert(!collection_set()->is_in(i), "New region should not be in collection set");
200 }
201 }
202
203 assert(_ordered_regions->active_regions() == _num_regions, "Must match");
204 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
205 "misaligned heap: "PTR_FORMAT, p2i(base()));
206
207 LogTarget(Trace, gc, region) lt;
208 if (lt.is_enabled()) {
209 ResourceMark rm;
210 LogStream ls(lt);
211 log_trace(gc, region)("All Regions");
212 _ordered_regions->print_on(&ls);
213 log_trace(gc, region)("Free Regions");
214 _free_regions->print_on(&ls);
215 }
216
217 _recycled_regions = NEW_C_HEAP_ARRAY(size_t, _num_regions, mtGC);
218
219 // The call below uses stuff (the SATB* things) that are in G1, but probably
220 // belong into a shared location.
221 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
222 SATB_Q_FL_lock,
223 20 /*G1SATBProcessCompletedThreshold */,
224 Shared_SATB_Q_lock);
225
226 // Reserve space for prev and next bitmap.
227 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
228 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
229
230 size_t bitmap_bytes_per_region = _bitmap_size / _num_regions;
231 _bitmap_words_per_region = bitmap_bytes_per_region / HeapWordSize;
232
233 guarantee(is_power_of_2(bitmap_bytes_per_region),
234 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
235 guarantee((bitmap_bytes_per_region % os::vm_page_size()) == 0,
236 "Bitmap bytes per region should be page-granular: bpr = " SIZE_FORMAT ", page size = %d",
237 bitmap_bytes_per_region, os::vm_page_size());
238 guarantee(is_power_of_2(_bitmap_words_per_region),
239 "Bitmap words per region Should be power of two: " SIZE_FORMAT, _bitmap_words_per_region);
240 guarantee(bitmap_bytes_per_region >= (size_t)os::vm_page_size(),
241 "Bitmap slice per region (" SIZE_FORMAT ") should be larger than page size (%d)",
242 bitmap_bytes_per_region, os::vm_page_size());
243
244 size_t bitmap_page_size = UseLargePages && (bitmap_bytes_per_region >= (size_t)os::large_page_size()) ?
245 (size_t)os::large_page_size() : (size_t)os::vm_page_size();
246
247 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
248 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
249 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
250
251 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
252 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
253 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
254
255 {
256 ShenandoahHeapLocker locker(lock());
257 for (size_t i = 0; i < _num_regions; i++) {
258 ShenandoahHeapRegion* r = _ordered_regions->get(i);
259 if (r->is_committed()) {
260 commit_bitmaps(r);
261 }
262 }
263 }
264
265 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
266
267 if (ShenandoahVerify) {
268 ReservedSpace verify_bitmap(_bitmap_size, page_size);
269 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
270 "couldn't allocate verification bitmap");
271 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
272 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
273 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
274 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
275 }
276
277 if (ShenandoahAlwaysPreTouch) {
278 assert (!AlwaysPreTouch, "Should have been overridden");
279
280 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
281 // before initialize() below zeroes it with initializing thread. For any given region,
282 // we touch the region and the corresponding bitmaps from the same thread.
283
284 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
285 _ordered_regions->count(), page_size);
286 ShenandoahPretouchTask cl(_ordered_regions, bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
287 _workers->run_task(&cl);
288 }
289
290 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
291 _complete_mark_bit_map = &_mark_bit_map0;
292
293 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
294 _next_mark_bit_map = &_mark_bit_map1;
295
296 if (UseShenandoahMatrix) {
297 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
298 } else {
299 _connection_matrix = NULL;
300 }
301
302 _partial_gc = _shenandoah_policy->can_do_partial_gc() ?
303 new ShenandoahPartialGC(this, _num_regions) :
304 NULL;
305
306 _monitoring_support = new ShenandoahMonitoringSupport(this);
307
308 _phase_timings = new ShenandoahPhaseTimings();
309
310 if (ShenandoahAllocationTrace) {
311 _alloc_tracker = new ShenandoahAllocTracker();
312 }
313
314 ShenandoahStringDedup::initialize();
315
316 _concurrent_gc_thread = new ShenandoahConcurrentThread();
317
318 ShenandoahMarkCompact::initialize();
319
320 ShenandoahCodeRoots::initialize();
321
322 return JNI_OK;
323 }
324
325 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
326 CollectedHeap(),
327 _shenandoah_policy(policy),
328 _concurrent_mark_in_progress(0),
329 _evacuation_in_progress(0),
330 _full_gc_in_progress(false),
331 _update_refs_in_progress(false),
332 _free_regions(NULL),
333 _collection_set(NULL),
334 _bytes_allocated_since_cm(0),
335 _bytes_allocated_during_cm(0),
336 _allocated_last_gc(0),
337 _used_start_gc(0),
338 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
339 _ref_processor(NULL),
340 _next_top_at_mark_starts(NULL),
341 _next_top_at_mark_starts_base(NULL),
342 _complete_top_at_mark_starts(NULL),
343 _complete_top_at_mark_starts_base(NULL),
344 _mark_bit_map0(),
345 _mark_bit_map1(),
346 _connection_matrix(NULL),
347 _cancelled_concgc(0),
348 _need_update_refs(false),
349 _need_reset_bitmaps(false),
350 _verifier(NULL),
351 _heap_lock(0),
352 _used_at_last_gc(0),
353 _alloc_seq_at_last_gc_start(0),
354 _alloc_seq_at_last_gc_end(0),
355 _safepoint_workers(NULL),
356 #ifdef ASSERT
357 _heap_lock_owner(NULL),
358 _heap_expansion_count(0),
359 #endif
360 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
361 _phase_timings(NULL),
362 _alloc_tracker(NULL)
363 {
364 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
365 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
366 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
367
368 _scm = new ShenandoahConcurrentMark();
369 _used = 0;
370
371 _max_workers = MAX2(_max_workers, 1U);
372 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
373 /* are_GC_task_threads */true,
374 /* are_ConcurrentGC_threads */false);
375 if (_workers == NULL) {
376 vm_exit_during_initialization("Failed necessary allocation.");
377 } else {
378 _workers->initialize_workers();
379 }
380
381 if (ParallelSafepointCleanupThreads > 1) {
382 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
383 ParallelSafepointCleanupThreads,
384 false, false);
385 _safepoint_workers->initialize_workers();
386 }
387 }
388
389 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
390 private:
391 ShenandoahHeapRegionSet* _regions;
392
393 public:
394 ShenandoahResetNextBitmapTask(ShenandoahHeapRegionSet* regions) :
395 AbstractGangTask("Parallel Reset Bitmap Task"),
396 _regions(regions) {
397 _regions->clear_current_index();
398 }
399
400 void work(uint worker_id) {
401 ShenandoahHeapRegion* region = _regions->claim_next();
402 ShenandoahHeap* heap = ShenandoahHeap::heap();
403 while (region != NULL) {
404 if (region->is_committed()) {
405 HeapWord* bottom = region->bottom();
406 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
407 if (top > bottom) {
408 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
409 }
410 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
411 }
412 region = _regions->claim_next();
413 }
414 }
415 };
416
417 void ShenandoahHeap::reset_next_mark_bitmap(WorkGang* workers) {
418 assert_gc_workers(workers->active_workers());
419
420 ShenandoahResetNextBitmapTask task = ShenandoahResetNextBitmapTask(_ordered_regions);
421 workers->run_task(&task);
422 }
423
424 class ShenandoahResetCompleteBitmapTask : public AbstractGangTask {
425 private:
426 ShenandoahHeapRegionSet* _regions;
427
428 public:
429 ShenandoahResetCompleteBitmapTask(ShenandoahHeapRegionSet* regions) :
430 AbstractGangTask("Parallel Reset Bitmap Task"),
431 _regions(regions) {
432 _regions->clear_current_index();
433 }
434
435 void work(uint worker_id) {
436 ShenandoahHeapRegion* region = _regions->claim_next();
437 ShenandoahHeap* heap = ShenandoahHeap::heap();
438 while (region != NULL) {
439 if (region->is_committed()) {
440 HeapWord* bottom = region->bottom();
441 HeapWord* top = heap->complete_top_at_mark_start(region->bottom());
442 if (top > bottom) {
443 heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
444 }
445 assert(heap->is_complete_bitmap_clear_range(bottom, region->end()), "must be clear");
446 }
447 region = _regions->claim_next();
448 }
449 }
450 };
451
452 void ShenandoahHeap::reset_complete_mark_bitmap(WorkGang* workers) {
453 assert_gc_workers(workers->active_workers());
454
455 ShenandoahResetCompleteBitmapTask task = ShenandoahResetCompleteBitmapTask(_ordered_regions);
456 workers->run_task(&task);
457 }
458
459 bool ShenandoahHeap::is_next_bitmap_clear() {
460 for (size_t idx = 0; idx < _num_regions; idx++) {
461 ShenandoahHeapRegion* r = _ordered_regions->get(idx);
462 if (r->is_committed() && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
463 return false;
464 }
465 }
466 return true;
467 }
468
469 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
470 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
471 }
472
473 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
474 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
475 }
476
477 void ShenandoahHeap::print_on(outputStream* st) const {
478 st->print_cr("Shenandoah Heap");
479 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
480 capacity() / K, committed() / K, used() / K);
481 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
482 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
483
484 st->print("Status: ");
485 if (concurrent_mark_in_progress()) {
486 st->print("marking ");
487 } else if (is_evacuation_in_progress()) {
488 st->print("evacuating ");
489 } else if (is_update_refs_in_progress()) {
490 st->print("updating refs ");
491 } else {
492 st->print("idle ");
493 }
494 if (cancelled_concgc()) {
495 st->print("cancelled ");
496 }
497 st->cr();
498
499 st->print_cr("Reserved region:");
500 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
501 p2i(reserved_region().start()),
502 p2i(reserved_region().end()));
503
504 if (UseShenandoahMatrix) {
505 st->print_cr("Matrix:");
506
507 ShenandoahConnectionMatrix* matrix = connection_matrix();
508 if (matrix != NULL) {
509 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
510 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
511 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
512 } else {
513 st->print_cr(" No matrix.");
514 }
515 }
516
517 if (Verbose) {
518 print_heap_regions_on(st);
519 }
520 }
521
522 class ShenandoahInitGCLABClosure : public ThreadClosure {
523 public:
524 void do_thread(Thread* thread) {
525 thread->gclab().initialize(true);
526 }
527 };
528
529 void ShenandoahHeap::post_initialize() {
530 if (UseTLAB) {
531 MutexLocker ml(Threads_lock);
532
533 ShenandoahInitGCLABClosure init_gclabs;
534 Threads::java_threads_do(&init_gclabs);
535 gc_threads_do(&init_gclabs);
536
537 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
538 // Now, we will let WorkGang to initialize gclab when new worker is created.
539 _workers->set_initialize_gclab();
540 }
541
542 _scm->initialize(_max_workers);
543
544 ref_processing_init();
545
546 _shenandoah_policy->post_heap_initialize();
547 }
548
549 size_t ShenandoahHeap::used() const {
550 OrderAccess::acquire();
551 return _used;
552 }
553
554 size_t ShenandoahHeap::committed() const {
555 OrderAccess::acquire();
556 return _committed;
557 }
558
559 void ShenandoahHeap::increase_committed(size_t bytes) {
560 assert_heaplock_or_safepoint();
561 _committed += bytes;
562 }
563
564 void ShenandoahHeap::decrease_committed(size_t bytes) {
565 assert_heaplock_or_safepoint();
566 _committed -= bytes;
567 }
568
569 void ShenandoahHeap::increase_used(size_t bytes) {
570 assert_heaplock_or_safepoint();
571 _used += bytes;
572 }
573
574 void ShenandoahHeap::set_used(size_t bytes) {
575 assert_heaplock_or_safepoint();
576 _used = bytes;
577 }
578
579 void ShenandoahHeap::decrease_used(size_t bytes) {
580 assert_heaplock_or_safepoint();
581 assert(_used >= bytes, "never decrease heap size by more than we've left");
582 _used -= bytes;
583 }
584
585 size_t ShenandoahHeap::capacity() const {
586 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
587 }
588
589 bool ShenandoahHeap::is_maximal_no_gc() const {
590 Unimplemented();
591 return true;
592 }
593
594 size_t ShenandoahHeap::max_capacity() const {
595 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
596 }
597
598 size_t ShenandoahHeap::initial_capacity() const {
599 return _initial_size;
600 }
601
602 bool ShenandoahHeap::is_in(const void* p) const {
603 HeapWord* heap_base = (HeapWord*) base();
604 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
605 return p >= heap_base && p < last_region_end;
606 }
607
608 bool ShenandoahHeap::is_scavengable(const void* p) {
609 return true;
610 }
611
612 void ShenandoahHeap::handle_heap_shrinkage() {
613 ShenandoahHeapLocker locker(lock());
614
615 ShenandoahHeapRegionSet* set = regions();
616
617 size_t count = 0;
618 double current = os::elapsedTime();
619 for (size_t i = 0; i < num_regions(); i++) {
620 ShenandoahHeapRegion* r = set->get(i);
621 if (r->is_empty_committed() &&
622 (current - r->empty_time()) * 1000 > ShenandoahUncommitDelay &&
623 r->make_empty_uncommitted()) {
624 count++;
625 }
626 }
627
628 if (count > 0) {
629 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
630 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
631 }
632 }
633
634 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
635 // Retain tlab and allocate object in shared space if
636 // the amount free in the tlab is too large to discard.
637 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
638 thread->gclab().record_slow_allocation(size);
639 return NULL;
640 }
641
642 // Discard gclab and allocate a new one.
643 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
644 size_t new_gclab_size = thread->gclab().compute_size(size);
645
646 thread->gclab().clear_before_allocation();
647
648 if (new_gclab_size == 0) {
649 return NULL;
650 }
651
652 // Allocate a new GCLAB...
653 HeapWord* obj = allocate_new_gclab(new_gclab_size);
654 if (obj == NULL) {
655 return NULL;
656 }
657
658 if (ZeroTLAB) {
659 // ..and clear it.
660 Copy::zero_to_words(obj, new_gclab_size);
661 } else {
662 // ...and zap just allocated object.
663 #ifdef ASSERT
664 // Skip mangling the space corresponding to the object header to
665 // ensure that the returned space is not considered parsable by
666 // any concurrent GC thread.
667 size_t hdr_size = oopDesc::header_size();
668 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
669 #endif // ASSERT
670 }
671 thread->gclab().fill(obj, obj + size, new_gclab_size);
672 return obj;
673 }
674
675 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
676 #ifdef ASSERT
677 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
678 #endif
679 return allocate_new_lab(word_size, _alloc_tlab);
680 }
681
682 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
683 #ifdef ASSERT
684 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
685 #endif
686 return allocate_new_lab(word_size, _alloc_gclab);
687 }
688
689 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
690 HeapWord* result = allocate_memory(word_size, type);
691
692 if (result != NULL) {
693 assert(! in_collection_set(result), "Never allocate in collection set");
694 _bytes_allocated_since_cm += word_size * HeapWordSize;
695
696 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
697
698 }
699 return result;
700 }
701
702 ShenandoahHeap* ShenandoahHeap::heap() {
703 CollectedHeap* heap = Universe::heap();
704 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
705 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
706 return (ShenandoahHeap*) heap;
707 }
708
709 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
710 CollectedHeap* heap = Universe::heap();
711 return (ShenandoahHeap*) heap;
712 }
713
714 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
715 ShenandoahAllocTrace trace_alloc(word_size, type);
716
717 bool in_new_region = false;
718 HeapWord* result = allocate_memory_under_lock(word_size, type, in_new_region);
719
720 if (type == _alloc_tlab || type == _alloc_shared) {
721 // Allocation failed, try full-GC, then retry allocation.
722 //
723 // It might happen that one of the threads requesting allocation would unblock
724 // way later after full-GC happened, only to fail the second allocation, because
725 // other threads have already depleted the free storage. In this case, a better
726 // strategy would be to try full-GC again.
727 //
728 // Lacking the way to detect progress from "collect" call, we are left with blindly
729 // retrying for some bounded number of times.
730 // TODO: Poll if Full GC made enough progress to warrant retry.
731 int tries = 0;
732 while ((result == NULL) && (tries++ < ShenandoahFullGCTries)) {
733 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing full GC, try %d",
734 p2i(Thread::current()), word_size * HeapWordSize, tries);
735 collect(GCCause::_allocation_failure);
736 result = allocate_memory_under_lock(word_size, type, in_new_region);
737 }
738 }
739
740 if (in_new_region) {
741 // Update monitoring counters when we took a new region. This amortizes the
742 // update costs on slow path.
743 concurrent_thread()->trigger_counters_update();
744 }
745
746 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
747 word_size, p2i(result), Thread::current()->osthread()->thread_id());
748
749 return result;
750 }
751
752 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
753 ShenandoahHeapLocker locker(lock());
754 return _free_regions->allocate(word_size, type, in_new_region);
755 }
756
757 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
758 bool* gc_overhead_limit_was_exceeded) {
759 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
760 HeapWord* result = filler + BrooksPointer::word_size();
761 if (filler != NULL) {
762 BrooksPointer::initialize(oop(result));
763 _bytes_allocated_since_cm += size * HeapWordSize;
764
765 assert(! in_collection_set(result), "never allocate in targetted region");
766 return result;
767 } else {
768 return NULL;
769 }
770 }
771
772 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
773 private:
774 ShenandoahHeap* _heap;
775 Thread* _thread;
776 public:
777 ShenandoahEvacuateUpdateRootsClosure() :
778 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
779 }
780
781 private:
782 template <class T>
783 void do_oop_work(T* p) {
784 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
785
786 T o = oopDesc::load_heap_oop(p);
787 if (! oopDesc::is_null(o)) {
788 oop obj = oopDesc::decode_heap_oop_not_null(o);
789 if (_heap->in_collection_set(obj)) {
790 assert(_heap->is_marked_complete(obj), "only evacuate marked objects %d %d",
791 _heap->is_marked_complete(obj), _heap->is_marked_complete(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)));
792 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
793 if (oopDesc::unsafe_equals(resolved, obj)) {
794 bool evac;
795 resolved = _heap->evacuate_object(obj, _thread, evac);
796 }
797 oopDesc::encode_store_heap_oop(p, resolved);
798 }
799 }
800 }
801
802 public:
803 void do_oop(oop* p) {
804 do_oop_work(p);
805 }
806 void do_oop(narrowOop* p) {
807 do_oop_work(p);
808 }
809 };
810
811 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
812 private:
813 ShenandoahHeap* _heap;
814 Thread* _thread;
815 public:
816 ShenandoahEvacuateRootsClosure() :
817 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
818 }
819
820 private:
821 template <class T>
822 void do_oop_work(T* p) {
823 T o = oopDesc::load_heap_oop(p);
824 if (! oopDesc::is_null(o)) {
825 oop obj = oopDesc::decode_heap_oop_not_null(o);
826 if (_heap->in_collection_set(obj)) {
827 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
828 if (oopDesc::unsafe_equals(resolved, obj)) {
829 bool evac;
830 _heap->evacuate_object(obj, _thread, evac);
831 }
832 }
833 }
834 }
835
836 public:
837 void do_oop(oop* p) {
838 do_oop_work(p);
839 }
840 void do_oop(narrowOop* p) {
841 do_oop_work(p);
842 }
843 };
844
845 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
846 private:
847 ShenandoahHeap* const _heap;
848 Thread* const _thread;
849 public:
850 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
851 _heap(heap), _thread(Thread::current()) {}
852
853 void do_object(oop p) {
854 assert(_heap->is_marked_complete(p), "expect only marked objects");
855 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p))) {
856 bool evac;
857 _heap->evacuate_object(p, _thread, evac);
858 }
859 }
860 };
861
862 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
863 private:
864 ShenandoahHeap* const _sh;
865 ShenandoahCollectionSet* const _cs;
866 volatile jbyte _claimed_codecache;
867
868 bool claim_codecache() {
869 jbyte old = Atomic::cmpxchg((jbyte)1, &_claimed_codecache, (jbyte)0);
870 return old == 0;
871 }
872 public:
873 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
874 ShenandoahCollectionSet* cs) :
875 AbstractGangTask("Parallel Evacuation Task"),
876 _cs(cs),
877 _sh(sh),
878 _claimed_codecache(0)
879 {}
880
881 void work(uint worker_id) {
882
883 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
884
885 // If concurrent code cache evac is enabled, evacuate it here.
886 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
887 // nmethods. The update would be handled elsewhere.
888 if (ShenandoahConcurrentEvacCodeRoots && claim_codecache()) {
889 ShenandoahEvacuateRootsClosure cl;
890 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
891 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
892 CodeCache::blobs_do(&blobs);
893 }
894
895 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
896 ShenandoahHeapRegion* r;
897 while ((r =_cs->claim_next()) != NULL) {
898 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
899 worker_id,
900 r->region_number());
901
902 assert(r->has_live(), "all-garbage regions are reclaimed early");
903 _sh->marked_object_iterate(r, &cl);
904
905 if (_sh->check_cancelled_concgc_and_yield()) {
906 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
907 break;
908 }
909 }
910 }
911 };
912
913 void ShenandoahHeap::trash_cset_regions() {
914 ShenandoahHeapLocker locker(lock());
915
916 ShenandoahCollectionSet* set = collection_set();
917 ShenandoahHeapRegion* r;
918 set->clear_current_index();
919 while ((r = set->next()) != NULL) {
920 r->make_trash();
921 }
922 collection_set()->clear();
923 }
924
925 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
926 st->print_cr("Heap Regions:");
927 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
928 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
929 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
930 st->print_cr("FTS=first use timestamp, LTS=last use timestamp");
931
932 _ordered_regions->print_on(st);
933 }
934
935 size_t ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
936 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
937
938 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
939 size_t size = humongous_obj->size() + BrooksPointer::word_size();
940 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
941 size_t index = start->region_number() + required_regions - 1;
942
943 assert(!start->has_live(), "liveness must be zero");
944 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
945
946 for(size_t i = 0; i < required_regions; i++) {
947 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
948 // as it expects that every region belongs to a humongous region starting with a humongous start region.
949 ShenandoahHeapRegion* region = _ordered_regions->get(index --);
950
951 LogTarget(Trace, gc, humongous) lt;
952 if (lt.is_enabled()) {
953 ResourceMark rm;
954 LogStream ls(lt);
955 region->print_on(&ls);
956 }
957
958 assert(region->is_humongous(), "expect correct humongous start or continuation");
959 assert(!in_collection_set(region), "Humongous region should not be in collection set");
960
961 region->make_trash();
962 }
963 return required_regions;
964 }
965
966 #ifdef ASSERT
967 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
968 bool heap_region_do(ShenandoahHeapRegion* r) {
969 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
970 return false;
971 }
972 };
973 #endif
974
975 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
976 assert(_ordered_regions->get(0)->region_number() == 0, "FIXME CHF. FIXME CHF!");
977
978 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
979
980 if (!cancelled_concgc()) {
981 // Allocations might have happened before we STWed here, record peak:
982 shenandoahPolicy()->record_peak_occupancy();
983
984 ensure_parsability(true);
985
986 if (ShenandoahVerify) {
987 verifier()->verify_after_concmark();
988 }
989
990 trash_cset_regions();
991
992 // NOTE: This needs to be done during a stop the world pause, because
993 // putting regions into the collection set concurrently with Java threads
994 // will create a race. In particular, acmp could fail because when we
995 // resolve the first operand, the containing region might not yet be in
996 // the collection set, and thus return the original oop. When the 2nd
997 // operand gets resolved, the region could be in the collection set
998 // and the oop gets evacuated. If both operands have originally been
999 // the same, we get false negatives.
1000
1001 {
1002 ShenandoahHeapLocker locker(lock());
1003 _collection_set->clear();
1004 _free_regions->clear();
1005
1006 #ifdef ASSERT
1007 ShenandoahCheckCollectionSetClosure ccsc;
1008 _ordered_regions->heap_region_iterate(&ccsc);
1009 #endif
1010
1011 _shenandoah_policy->choose_collection_set(_collection_set);
1012
1013 _shenandoah_policy->choose_free_set(_free_regions);
1014 }
1015
1016 _bytes_allocated_since_cm = 0;
1017
1018 Universe::update_heap_info_at_gc();
1019
1020 if (ShenandoahVerify) {
1021 verifier()->verify_before_evacuation();
1022 }
1023 }
1024 }
1025
1026
1027 class ShenandoahRetireTLABClosure : public ThreadClosure {
1028 private:
1029 bool _retire;
1030
1031 public:
1032 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1033
1034 void do_thread(Thread* thread) {
1035 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1036 thread->gclab().make_parsable(_retire);
1037 }
1038 };
1039
1040 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1041 if (UseTLAB) {
1042 CollectedHeap::ensure_parsability(retire_tlabs);
1043 ShenandoahRetireTLABClosure cl(retire_tlabs);
1044 Threads::java_threads_do(&cl);
1045 gc_threads_do(&cl);
1046 }
1047 }
1048
1049
1050 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1051 ShenandoahRootEvacuator* _rp;
1052 public:
1053
1054 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1055 AbstractGangTask("Shenandoah evacuate and update roots"),
1056 _rp(rp)
1057 {
1058 // Nothing else to do.
1059 }
1060
1061 void work(uint worker_id) {
1062 ShenandoahEvacuateUpdateRootsClosure cl;
1063
1064 if (ShenandoahConcurrentEvacCodeRoots) {
1065 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1066 } else {
1067 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1068 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1069 }
1070 }
1071 };
1072
1073 class ShenandoahFixRootsTask : public AbstractGangTask {
1074 ShenandoahRootEvacuator* _rp;
1075 public:
1076
1077 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1078 AbstractGangTask("Shenandoah update roots"),
1079 _rp(rp)
1080 {
1081 // Nothing else to do.
1082 }
1083
1084 void work(uint worker_id) {
1085 ShenandoahUpdateRefsClosure cl;
1086 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1087
1088 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1089 }
1090 };
1091
1092 void ShenandoahHeap::evacuate_and_update_roots() {
1093
1094 #if defined(COMPILER2) || INCLUDE_JVMCI
1095 DerivedPointerTable::clear();
1096 #endif
1097 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1098
1099 {
1100 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1101 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1102 workers()->run_task(&roots_task);
1103 }
1104
1105 #if defined(COMPILER2) || INCLUDE_JVMCI
1106 DerivedPointerTable::update_pointers();
1107 #endif
1108 if (cancelled_concgc()) {
1109 fixup_roots();
1110 }
1111 }
1112
1113
1114 void ShenandoahHeap::fixup_roots() {
1115 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1116
1117 // If initial evacuation has been cancelled, we need to update all references
1118 // after all workers have finished. Otherwise we might run into the following problem:
1119 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1120 // GC thread 2 evacuates the same object X to to-space
1121 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1122 // clear() and update_pointers() must always be called in pairs,
1123 // cannot nest with above clear()/update_pointers().
1124 #if defined(COMPILER2) || INCLUDE_JVMCI
1125 DerivedPointerTable::clear();
1126 #endif
1127 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1128 ShenandoahFixRootsTask update_roots_task(&rp);
1129 workers()->run_task(&update_roots_task);
1130 #if defined(COMPILER2) || INCLUDE_JVMCI
1131 DerivedPointerTable::update_pointers();
1132 #endif
1133 }
1134
1135 void ShenandoahHeap::do_evacuation() {
1136 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
1137
1138 LogTarget(Trace, gc, region) lt_region;
1139 LogTarget(Trace, gc, cset) lt_cset;
1140
1141 if (lt_region.is_enabled()) {
1142 ResourceMark rm;
1143 LogStream ls(lt_region);
1144 ls.print_cr("All available regions:");
1145 print_heap_regions_on(&ls);
1146 }
1147
1148 if (lt_cset.is_enabled()) {
1149 ResourceMark rm;
1150 LogStream ls(lt_cset);
1151 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1152 _collection_set->print_on(&ls);
1153
1154 ls.print_cr("Free set:");
1155 _free_regions->print_on(&ls);
1156 }
1157
1158 ShenandoahParallelEvacuationTask task(this, _collection_set);
1159 workers()->run_task(&task);
1160
1161 if (lt_cset.is_enabled()) {
1162 ResourceMark rm;
1163 LogStream ls(lt_cset);
1164 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1165 _collection_set->count());
1166 _collection_set->print_on(&ls);
1167
1168 ls.print_cr("After evacuation free set:");
1169 _free_regions->print_on(&ls);
1170 }
1171
1172 if (lt_region.is_enabled()) {
1173 ResourceMark rm;
1174 LogStream ls(lt_region);
1175 ls.print_cr("All regions after evacuation:");
1176 print_heap_regions_on(&ls);
1177 }
1178 }
1179
1180 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1181 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1182
1183 CodeBlobToOopClosure blobsCl(cl, false);
1184 CLDToOopClosure cldCl(cl);
1185
1186 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1187 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, 0);
1188 }
1189
1190 bool ShenandoahHeap::supports_tlab_allocation() const {
1191 return true;
1192 }
1193
1194 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1195 return MIN2(_free_regions->unsafe_peek_free(), max_tlab_size());
1196 }
1197
1198 size_t ShenandoahHeap::max_tlab_size() const {
1199 return ShenandoahHeapRegion::max_tlab_size_bytes();
1200 }
1201
1202 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1203 public:
1204 void do_thread(Thread* thread) {
1205 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1206 thread->gclab().resize();
1207 }
1208 };
1209
1210 void ShenandoahHeap::resize_all_tlabs() {
1211 CollectedHeap::resize_all_tlabs();
1212
1213 ShenandoahResizeGCLABClosure cl;
1214 Threads::java_threads_do(&cl);
1215 gc_threads_do(&cl);
1216 }
1217
1218 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1219 public:
1220 void do_thread(Thread* thread) {
1221 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1222 thread->gclab().accumulate_statistics();
1223 thread->gclab().initialize_statistics();
1224 }
1225 };
1226
1227 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1228 ShenandoahAccumulateStatisticsGCLABClosure cl;
1229 Threads::java_threads_do(&cl);
1230 gc_threads_do(&cl);
1231 }
1232
1233 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1234 return true;
1235 }
1236
1237 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1238 // Overridden to do nothing.
1239 return new_obj;
1240 }
1241
1242 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1243 return true;
1244 }
1245
1246 bool ShenandoahHeap::card_mark_must_follow_store() const {
1247 return false;
1248 }
1249
1250 void ShenandoahHeap::collect(GCCause::Cause cause) {
1251 assert(cause != GCCause::_gc_locker, "no JNI critical callback");
1252 if (GCCause::is_user_requested_gc(cause)) {
1253 if (!DisableExplicitGC) {
1254 if (ExplicitGCInvokesConcurrent) {
1255 _concurrent_gc_thread->do_conc_gc();
1256 } else {
1257 _concurrent_gc_thread->do_full_gc(cause);
1258 }
1259 }
1260 } else if (cause == GCCause::_allocation_failure) {
1261 collector_policy()->set_should_clear_all_soft_refs(true);
1262 _concurrent_gc_thread->do_full_gc(cause);
1263 }
1264 }
1265
1266 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1267 //assert(false, "Shouldn't need to do full collections");
1268 }
1269
1270 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1271 Unimplemented();
1272 return NULL;
1273
1274 }
1275
1276 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1277 return _shenandoah_policy;
1278 }
1279
1280
1281 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1282 Space* sp = heap_region_containing(addr);
1283 if (sp != NULL) {
1284 return sp->block_start(addr);
1285 }
1286 return NULL;
1287 }
1288
1289 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1290 Space* sp = heap_region_containing(addr);
1291 assert(sp != NULL, "block_size of address outside of heap");
1292 return sp->block_size(addr);
1293 }
1294
1295 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1296 Space* sp = heap_region_containing(addr);
1297 return sp->block_is_obj(addr);
1298 }
1299
1300 jlong ShenandoahHeap::millis_since_last_gc() {
1301 return 0;
1302 }
1303
1304 void ShenandoahHeap::prepare_for_verify() {
1305 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1306 ensure_parsability(false);
1307 }
1308 }
1309
1310 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1311 workers()->print_worker_threads_on(st);
1312 }
1313
1314 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1315 workers()->threads_do(tcl);
1316 }
1317
1318 void ShenandoahHeap::print_tracing_info() const {
1319 LogTarget(Info, gc, stats) lt;
1320 if (lt.is_enabled()) {
1321 ResourceMark rm;
1322 LogStream ls(lt);
1323
1324 phase_timings()->print_on(&ls);
1325
1326 ls.cr();
1327 ls.cr();
1328
1329 shenandoahPolicy()->print_gc_stats(&ls);
1330
1331 ls.cr();
1332 ls.cr();
1333
1334 if (ShenandoahAllocationTrace) {
1335 assert(alloc_tracker() != NULL, "Must be");
1336 alloc_tracker()->print_on(&ls);
1337 } else {
1338 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1339 }
1340 }
1341 }
1342
1343 void ShenandoahHeap::verify(VerifyOption vo) {
1344 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1345 if (ShenandoahVerify) {
1346 verifier()->verify_generic(vo);
1347 } else {
1348 // TODO: Consider allocating verification bitmaps on demand,
1349 // and turn this on unconditionally.
1350 }
1351 }
1352 }
1353 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1354 return _free_regions->capacity();
1355 }
1356
1357 class ShenandoahIterateObjectClosureRegionClosure: public ShenandoahHeapRegionClosure {
1358 ObjectClosure* _cl;
1359 public:
1360 ShenandoahIterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
1361 bool heap_region_do(ShenandoahHeapRegion* r) {
1362 ShenandoahHeap::heap()->marked_object_iterate(r, _cl);
1363 return false;
1364 }
1365 };
1366
1367 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1368 ShenandoahIterateObjectClosureRegionClosure blk(cl);
1369 heap_region_iterate(&blk, false, true);
1370 }
1371
1372 class ShenandoahSafeObjectIterateAdjustPtrsClosure : public MetadataAwareOopClosure {
1373 private:
1374 ShenandoahHeap* _heap;
1375
1376 public:
1377 ShenandoahSafeObjectIterateAdjustPtrsClosure() : _heap(ShenandoahHeap::heap()) {}
1378
1379 private:
1380 template <class T>
1381 inline void do_oop_work(T* p) {
1382 T o = oopDesc::load_heap_oop(p);
1383 if (!oopDesc::is_null(o)) {
1384 oop obj = oopDesc::decode_heap_oop_not_null(o);
1385 oopDesc::encode_store_heap_oop(p, BrooksPointer::forwardee(obj));
1386 }
1387 }
1388 public:
1389 void do_oop(oop* p) {
1390 do_oop_work(p);
1391 }
1392 void do_oop(narrowOop* p) {
1393 do_oop_work(p);
1394 }
1395 };
1396
1397 class ShenandoahSafeObjectIterateAndUpdate : public ObjectClosure {
1398 private:
1399 ObjectClosure* _cl;
1400 public:
1401 ShenandoahSafeObjectIterateAndUpdate(ObjectClosure *cl) : _cl(cl) {}
1402
1403 virtual void do_object(oop obj) {
1404 assert (oopDesc::unsafe_equals(obj, BrooksPointer::forwardee(obj)),
1405 "avoid double-counting: only non-forwarded objects here");
1406
1407 // Fix up the ptrs.
1408 ShenandoahSafeObjectIterateAdjustPtrsClosure adjust_ptrs;
1409 obj->oop_iterate(&adjust_ptrs);
1410
1411 // Can reply the object now:
1412 _cl->do_object(obj);
1413 }
1414 };
1415
1416 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1417 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1418
1419 // Safe iteration does objects only with correct references.
1420 // This is why we skip collection set regions that have stale copies of objects,
1421 // and fix up the pointers in the returned objects.
1422
1423 ShenandoahSafeObjectIterateAndUpdate safe_cl(cl);
1424 ShenandoahIterateObjectClosureRegionClosure blk(&safe_cl);
1425 heap_region_iterate(&blk,
1426 /* skip_cset_regions = */ true,
1427 /* skip_humongous_continuations = */ true);
1428
1429 _need_update_refs = false; // already updated the references
1430 }
1431
1432 // Apply blk->heap_region_do() on all committed regions in address order,
1433 // terminating the iteration early if heap_region_do() returns true.
1434 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1435 for (size_t i = 0; i < num_regions(); i++) {
1436 ShenandoahHeapRegion* current = _ordered_regions->get(i);
1437 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1438 continue;
1439 }
1440 if (skip_cset_regions && in_collection_set(current)) {
1441 continue;
1442 }
1443 if (blk->heap_region_do(current)) {
1444 return;
1445 }
1446 }
1447 }
1448
1449 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1450 private:
1451 ShenandoahHeap* sh;
1452 public:
1453 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1454
1455 bool heap_region_do(ShenandoahHeapRegion* r) {
1456 r->clear_live_data();
1457 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1458 return false;
1459 }
1460 };
1461
1462 void ShenandoahHeap::start_concurrent_marking() {
1463 if (ShenandoahVerify) {
1464 verifier()->verify_before_concmark();
1465 }
1466
1467 {
1468 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1469 accumulate_statistics_all_tlabs();
1470 }
1471
1472 set_concurrent_mark_in_progress(true);
1473 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1474 if (UseTLAB) {
1475 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1476 ensure_parsability(true);
1477 }
1478
1479 _shenandoah_policy->record_bytes_allocated(_bytes_allocated_since_cm);
1480 _used_start_gc = used();
1481
1482 {
1483 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1484 ShenandoahClearLivenessClosure clc(this);
1485 heap_region_iterate(&clc);
1486 }
1487
1488 // Make above changes visible to worker threads
1489 OrderAccess::fence();
1490
1491 concurrentMark()->init_mark_roots();
1492
1493 if (UseTLAB) {
1494 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1495 resize_all_tlabs();
1496 }
1497 }
1498
1499 void ShenandoahHeap::swap_mark_bitmaps() {
1500 // Swap bitmaps.
1501 MarkBitMap* tmp1 = _complete_mark_bit_map;
1502 _complete_mark_bit_map = _next_mark_bit_map;
1503 _next_mark_bit_map = tmp1;
1504
1505 // Swap top-at-mark-start pointers
1506 HeapWord** tmp2 = _complete_top_at_mark_starts;
1507 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1508 _next_top_at_mark_starts = tmp2;
1509
1510 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1511 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1512 _next_top_at_mark_starts_base = tmp3;
1513 }
1514
1515
1516 void ShenandoahHeap::stop_concurrent_marking() {
1517 assert(concurrent_mark_in_progress(), "How else could we get here?");
1518 if (! cancelled_concgc()) {
1519 // If we needed to update refs, and concurrent marking has been cancelled,
1520 // we need to finish updating references.
1521 set_need_update_refs(false);
1522 swap_mark_bitmaps();
1523 }
1524 set_concurrent_mark_in_progress(false);
1525
1526 LogTarget(Trace, gc, region) lt;
1527 if (lt.is_enabled()) {
1528 ResourceMark rm;
1529 LogStream ls(lt);
1530 ls.print_cr("Regions at stopping the concurrent mark:");
1531 print_heap_regions_on(&ls);
1532 }
1533 }
1534
1535 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1536 _concurrent_mark_in_progress = in_progress ? 1 : 0;
1537 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1538 }
1539
1540 void ShenandoahHeap::set_evacuation_in_progress_concurrently(bool in_progress) {
1541 // Note: it is important to first release the _evacuation_in_progress flag here,
1542 // so that Java threads can get out of oom_during_evacuation() and reach a safepoint,
1543 // in case a VM task is pending.
1544 set_evacuation_in_progress(in_progress);
1545 MutexLocker mu(Threads_lock);
1546 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1547 }
1548
1549 void ShenandoahHeap::set_evacuation_in_progress_at_safepoint(bool in_progress) {
1550 assert(SafepointSynchronize::is_at_safepoint(), "Only call this at safepoint");
1551 set_evacuation_in_progress(in_progress);
1552 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1553 }
1554
1555 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1556 _evacuation_in_progress = in_progress ? 1 : 0;
1557 OrderAccess::fence();
1558 }
1559
1560 void ShenandoahHeap::oom_during_evacuation() {
1561 log_develop_trace(gc)("Out of memory during evacuation, cancel evacuation, schedule full GC by thread %d",
1562 Thread::current()->osthread()->thread_id());
1563
1564 // We ran out of memory during evacuation. Cancel evacuation, and schedule a full-GC.
1565 collector_policy()->set_should_clear_all_soft_refs(true);
1566 concurrent_thread()->try_set_full_gc();
1567 cancel_concgc(_oom_evacuation);
1568
1569 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
1570 assert(! Threads_lock->owned_by_self()
1571 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here");
1572 log_warning(gc)("OOM during evacuation. Let Java thread wait until evacuation finishes.");
1573 while (_evacuation_in_progress) { // wait.
1574 Thread::current()->_ParkEvent->park(1);
1575 }
1576 }
1577
1578 }
1579
1580 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1581 // Initialize Brooks pointer for the next object
1582 HeapWord* result = obj + BrooksPointer::word_size();
1583 BrooksPointer::initialize(oop(result));
1584 return result;
1585 }
1586
1587 uint ShenandoahHeap::oop_extra_words() {
1588 return BrooksPointer::word_size();
1589 }
1590
1591 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1592 _heap(ShenandoahHeap::heap_no_check()) {
1593 }
1594
1595 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1596 assert(_heap != NULL, "sanity");
1597 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1598 #ifdef ASSERT
1599 if (_heap->concurrent_mark_in_progress()) {
1600 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1601 }
1602 #endif
1603 assert(!oopDesc::is_null(obj), "null");
1604 return _heap->is_marked_next(obj);
1605 }
1606
1607 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1608 _heap(ShenandoahHeap::heap_no_check()) {
1609 }
1610
1611 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1612 assert(_heap != NULL, "sanity");
1613 assert(!oopDesc::is_null(obj), "null");
1614 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1615 return _heap->is_marked_next(obj);
1616 }
1617
1618 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1619 return need_update_refs() ?
1620 (BoolObjectClosure*) &_forwarded_is_alive :
1621 (BoolObjectClosure*) &_is_alive;
1622 }
1623
1624 void ShenandoahHeap::ref_processing_init() {
1625 MemRegion mr = reserved_region();
1626
1627 _forwarded_is_alive.init(ShenandoahHeap::heap());
1628 _is_alive.init(ShenandoahHeap::heap());
1629 assert(_max_workers > 0, "Sanity");
1630
1631 _ref_processor =
1632 new ReferenceProcessor(mr, // span
1633 ParallelRefProcEnabled, // MT processing
1634 _max_workers, // Degree of MT processing
1635 true, // MT discovery
1636 _max_workers, // Degree of MT discovery
1637 false, // Reference discovery is not atomic
1638 &_forwarded_is_alive); // Pessimistically assume "forwarded"
1639 }
1640
1641
1642 GCTracer* ShenandoahHeap::tracer() {
1643 return shenandoahPolicy()->tracer();
1644 }
1645
1646 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1647 return _free_regions->used();
1648 }
1649
1650 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1651 if (try_cancel_concgc()) {
1652 log_info(gc)("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1653 _shenandoah_policy->report_concgc_cancelled();
1654 }
1655 }
1656
1657 void ShenandoahHeap::cancel_concgc(ShenandoahCancelCause cause) {
1658 if (try_cancel_concgc()) {
1659 log_info(gc)("Cancelling concurrent GC: %s", cancel_cause_to_string(cause));
1660 _shenandoah_policy->report_concgc_cancelled();
1661 }
1662 }
1663
1664 const char* ShenandoahHeap::cancel_cause_to_string(ShenandoahCancelCause cause) {
1665 switch (cause) {
1666 case _oom_evacuation:
1667 return "Out of memory for evacuation";
1668 case _vm_stop:
1669 return "Stopping VM";
1670 default:
1671 return "Unknown";
1672 }
1673 }
1674
1675 uint ShenandoahHeap::max_workers() {
1676 return _max_workers;
1677 }
1678
1679 void ShenandoahHeap::stop() {
1680 // The shutdown sequence should be able to terminate when GC is running.
1681
1682 // Step 0. Notify policy to disable event recording.
1683 _shenandoah_policy->record_shutdown();
1684
1685 // Step 1. Notify control thread that we are in shutdown.
1686 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1687 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1688 _concurrent_gc_thread->prepare_for_graceful_shutdown();
1689
1690 // Step 2. Notify GC workers that we are cancelling GC.
1691 cancel_concgc(_vm_stop);
1692
1693 // Step 3. Wait until GC worker exits normally.
1694 _concurrent_gc_thread->stop();
1695 }
1696
1697 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1698 ShenandoahPhaseTimings::Phase phase_root =
1699 full_gc ?
1700 ShenandoahPhaseTimings::full_gc_purge :
1701 ShenandoahPhaseTimings::purge;
1702
1703 ShenandoahPhaseTimings::Phase phase_unload =
1704 full_gc ?
1705 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1706 ShenandoahPhaseTimings::purge_class_unload;
1707
1708 ShenandoahPhaseTimings::Phase phase_cldg =
1709 full_gc ?
1710 ShenandoahPhaseTimings::full_gc_purge_cldg :
1711 ShenandoahPhaseTimings::purge_cldg;
1712
1713 ShenandoahPhaseTimings::Phase phase_par =
1714 full_gc ?
1715 ShenandoahPhaseTimings::full_gc_purge_par :
1716 ShenandoahPhaseTimings::purge_par;
1717
1718 ShenandoahPhaseTimings::Phase phase_par_classes =
1719 full_gc ?
1720 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1721 ShenandoahPhaseTimings::purge_par_classes;
1722
1723 ShenandoahPhaseTimings::Phase phase_par_codecache =
1724 full_gc ?
1725 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1726 ShenandoahPhaseTimings::purge_par_codecache;
1727
1728 ShenandoahPhaseTimings::Phase phase_par_rmt =
1729 full_gc ?
1730 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
1731 ShenandoahPhaseTimings::purge_par_rmt;
1732
1733 ShenandoahPhaseTimings::Phase phase_par_symbstring =
1734 full_gc ?
1735 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
1736 ShenandoahPhaseTimings::purge_par_symbstring;
1737
1738 ShenandoahPhaseTimings::Phase phase_par_sync =
1739 full_gc ?
1740 ShenandoahPhaseTimings::full_gc_purge_par_sync :
1741 ShenandoahPhaseTimings::purge_par_sync;
1742
1743 ShenandoahGCPhase root_phase(phase_root);
1744
1745 BoolObjectClosure* is_alive = is_alive_closure();
1746
1747 bool purged_class;
1748
1749 // Unload classes and purge SystemDictionary.
1750 {
1751 ShenandoahGCPhase phase(phase_unload);
1752 purged_class = SystemDictionary::do_unloading(is_alive,
1753 full_gc ? ShenandoahMarkCompact::gc_timer() : gc_timer(),
1754 true);
1755 }
1756
1757 {
1758 ShenandoahGCPhase phase(phase_par);
1759 uint active = _workers->active_workers();
1760 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
1761 _workers->run_task(&unlink_task);
1762
1763 ShenandoahPhaseTimings* p = ShenandoahHeap::heap()->phase_timings();
1764 ParallelCleaningTimes times = unlink_task.times();
1765
1766 // "times" report total time, phase_tables_cc reports wall time. Divide total times
1767 // by active workers to get average time per worker, that would add up to wall time.
1768 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
1769 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
1770 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
1771 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
1772 p->record_phase_time(phase_par_sync, times.sync_us() / active);
1773 }
1774
1775 {
1776 ShenandoahGCPhase phase(phase_cldg);
1777 ClassLoaderDataGraph::purge();
1778 }
1779 }
1780
1781 void ShenandoahHeap::set_need_update_refs(bool need_update_refs) {
1782 _need_update_refs = need_update_refs;
1783 }
1784
1785 //fixme this should be in heapregionset
1786 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
1787 size_t region_idx = r->region_number() + 1;
1788 ShenandoahHeapRegion* next = _ordered_regions->get(region_idx);
1789 guarantee(next->region_number() == region_idx, "region number must match");
1790 while (next->is_humongous()) {
1791 region_idx = next->region_number() + 1;
1792 next = _ordered_regions->get(region_idx);
1793 guarantee(next->region_number() == region_idx, "region number must match");
1794 }
1795 return next;
1796 }
1797
1798 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
1799 return _monitoring_support;
1800 }
1801
1802 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
1803 return _complete_mark_bit_map;
1804 }
1805
1806 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
1807 return _next_mark_bit_map;
1808 }
1809
1810 void ShenandoahHeap::add_free_region(ShenandoahHeapRegion* r) {
1811 _free_regions->add_region(r);
1812 }
1813
1814 void ShenandoahHeap::clear_free_regions() {
1815 _free_regions->clear();
1816 }
1817
1818 address ShenandoahHeap::in_cset_fast_test_addr() {
1819 ShenandoahHeap* heap = ShenandoahHeap::heap();
1820 assert(heap->collection_set() != NULL, "Sanity");
1821 return (address) heap->collection_set()->biased_map_address();
1822 }
1823
1824 address ShenandoahHeap::cancelled_concgc_addr() {
1825 return (address) &(ShenandoahHeap::heap()->_cancelled_concgc);
1826 }
1827
1828
1829 size_t ShenandoahHeap::conservative_max_heap_alignment() {
1830 return ShenandoahMaxRegionSize;
1831 }
1832
1833 size_t ShenandoahHeap::bytes_allocated_since_cm() {
1834 return _bytes_allocated_since_cm;
1835 }
1836
1837 void ShenandoahHeap::set_bytes_allocated_since_cm(size_t bytes) {
1838 _bytes_allocated_since_cm = bytes;
1839 }
1840
1841 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
1842 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1843 _next_top_at_mark_starts[index] = addr;
1844 }
1845
1846 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
1847 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1848 return _next_top_at_mark_starts[index];
1849 }
1850
1851 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
1852 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1853 _complete_top_at_mark_starts[index] = addr;
1854 }
1855
1856 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
1857 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1858 return _complete_top_at_mark_starts[index];
1859 }
1860
1861 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1862 _full_gc_in_progress = in_progress;
1863 }
1864
1865 bool ShenandoahHeap::is_full_gc_in_progress() const {
1866 return _full_gc_in_progress;
1867 }
1868
1869 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1870 _update_refs_in_progress = in_progress;
1871 }
1872
1873 bool ShenandoahHeap::is_update_refs_in_progress() const {
1874 return _update_refs_in_progress;
1875 }
1876
1877 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1878 ShenandoahCodeRoots::add_nmethod(nm);
1879 }
1880
1881 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
1882 ShenandoahCodeRoots::remove_nmethod(nm);
1883 }
1884
1885 void ShenandoahHeap::pin_object(oop o) {
1886 ShenandoahHeapLocker locker(lock());
1887 heap_region_containing(o)->make_pinned();
1888 }
1889
1890 void ShenandoahHeap::unpin_object(oop o) {
1891 ShenandoahHeapLocker locker(lock());
1892 heap_region_containing(o)->make_unpinned();
1893 }
1894
1895 GCTimer* ShenandoahHeap::gc_timer() const {
1896 return _gc_timer;
1897 }
1898
1899 #ifdef ASSERT
1900 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
1901 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
1902
1903 if (SafepointSynchronize::is_at_safepoint()) {
1904 if (UseDynamicNumberOfGCThreads ||
1905 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
1906 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
1907 } else {
1908 // Use ParallelGCThreads inside safepoints
1909 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
1910 }
1911 } else {
1912 if (UseDynamicNumberOfGCThreads ||
1913 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
1914 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
1915 } else {
1916 // Use ConcGCThreads outside safepoints
1917 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
1918 }
1919 }
1920 }
1921 #endif
1922
1923 class ShenandoahCountGarbageClosure : public ShenandoahHeapRegionClosure {
1924 private:
1925 size_t _garbage;
1926 public:
1927 ShenandoahCountGarbageClosure() : _garbage(0) {
1928 }
1929
1930 bool heap_region_do(ShenandoahHeapRegion* r) {
1931 if (r->is_regular()) {
1932 _garbage += r->garbage();
1933 }
1934 return false;
1935 }
1936
1937 size_t garbage() {
1938 return _garbage;
1939 }
1940 };
1941
1942 size_t ShenandoahHeap::garbage() {
1943 ShenandoahCountGarbageClosure cl;
1944 heap_region_iterate(&cl);
1945 return cl.garbage();
1946 }
1947
1948 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
1949 return _connection_matrix;
1950 }
1951
1952 ShenandoahPartialGC* ShenandoahHeap::partial_gc() {
1953 return _partial_gc;
1954 }
1955
1956 void ShenandoahHeap::do_partial_collection() {
1957 partial_gc()->do_partial_collection();
1958 }
1959
1960 ShenandoahVerifier* ShenandoahHeap::verifier() {
1961 guarantee(ShenandoahVerify, "Should be enabled");
1962 assert (_verifier != NULL, "sanity");
1963 return _verifier;
1964 }
1965
1966 template<class T>
1967 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
1968 private:
1969 T cl;
1970 ShenandoahHeap* _heap;
1971 ShenandoahHeapRegionSet* _regions;
1972 bool _concurrent;
1973 public:
1974 ShenandoahUpdateHeapRefsTask(ShenandoahHeapRegionSet* regions, bool concurrent) :
1975 AbstractGangTask("Concurrent Update References Task"),
1976 cl(T()),
1977 _heap(ShenandoahHeap::heap()),
1978 _regions(regions),
1979 _concurrent(concurrent) {
1980 }
1981
1982 void work(uint worker_id) {
1983 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
1984 ShenandoahHeapRegion* r = _regions->claim_next();
1985 while (r != NULL) {
1986 if (_heap->in_collection_set(r)) {
1987 HeapWord* bottom = r->bottom();
1988 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
1989 if (top > bottom) {
1990 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
1991 }
1992 } else {
1993 if (r->is_active()) {
1994 _heap->marked_object_oop_safe_iterate(r, &cl);
1995 }
1996 }
1997 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
1998 return;
1999 }
2000 r = _regions->claim_next();
2001 }
2002 }
2003 };
2004
2005 void ShenandoahHeap::update_heap_references(ShenandoahHeapRegionSet* update_regions, bool concurrent) {
2006 if (UseShenandoahMatrix) {
2007 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(update_regions, concurrent);
2008 workers()->run_task(&task);
2009 } else {
2010 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(update_regions, concurrent);
2011 workers()->run_task(&task);
2012 }
2013 }
2014
2015 void ShenandoahHeap::concurrent_update_heap_references() {
2016 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2017 ShenandoahHeapRegionSet* update_regions = regions();
2018 update_regions->clear_current_index();
2019 update_heap_references(update_regions, true);
2020 }
2021
2022 void ShenandoahHeap::prepare_update_refs() {
2023 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2024
2025 if (ShenandoahVerify) {
2026 verifier()->verify_before_updaterefs();
2027 }
2028
2029 set_evacuation_in_progress_at_safepoint(false);
2030 set_update_refs_in_progress(true);
2031 ensure_parsability(true);
2032 if (UseShenandoahMatrix) {
2033 connection_matrix()->clear_all();
2034 }
2035 for (uint i = 0; i < num_regions(); i++) {
2036 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2037 r->set_concurrent_iteration_safe_limit(r->top());
2038 }
2039 }
2040
2041 void ShenandoahHeap::finish_update_refs() {
2042 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2043
2044 if (cancelled_concgc()) {
2045 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2046
2047 // Finish updating references where we left off.
2048 clear_cancelled_concgc();
2049 ShenandoahHeapRegionSet* update_regions = regions();
2050 update_heap_references(update_regions, false);
2051 }
2052
2053 assert(! cancelled_concgc(), "Should have been done right before");
2054 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2055
2056 if (ShenandoahStringDedup::is_enabled()) {
2057 ShenandoahGCPhase final_str_dedup_table(ShenandoahPhaseTimings::final_update_refs_dedup_table);
2058 ShenandoahStringDedup::parallel_update_refs();
2059 }
2060
2061 // Allocations might have happened before we STWed here, record peak:
2062 shenandoahPolicy()->record_peak_occupancy();
2063
2064 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2065
2066 trash_cset_regions();
2067 set_need_update_refs(false);
2068
2069 if (ShenandoahVerify) {
2070 verifier()->verify_after_updaterefs();
2071 }
2072
2073 {
2074 // Rebuild the free set
2075 ShenandoahHeapLocker locker(lock());
2076 _free_regions->clear();
2077 size_t end = _ordered_regions->active_regions();
2078 for (size_t i = 0; i < end; i++) {
2079 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2080 if (r->is_alloc_allowed()) {
2081 assert (!in_collection_set(r), "collection set should be clear");
2082 _free_regions->add_region(r);
2083 }
2084 }
2085 }
2086 set_update_refs_in_progress(false);
2087 }
2088
2089 void ShenandoahHeap::set_alloc_seq_gc_start() {
2090 // Take next number, the start seq number is inclusive
2091 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::alloc_seq_num() + 1;
2092 }
2093
2094 void ShenandoahHeap::set_alloc_seq_gc_end() {
2095 // Take current number, the end seq number is also inclusive
2096 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::alloc_seq_num();
2097 }
2098
2099
2100 #ifdef ASSERT
2101 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2102 _lock.assert_owned_by_current_thread();
2103 }
2104
2105 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2106 _lock.assert_not_owned_by_current_thread();
2107 }
2108
2109 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2110 _lock.assert_owned_by_current_thread_or_safepoint();
2111 }
2112 #endif
2113
2114 void ShenandoahHeap::recycle_trash_assist(size_t limit) {
2115 assert_heaplock_owned_by_current_thread();
2116
2117 size_t count = 0;
2118 for (size_t i = 0; (i < num_regions()) && (count < limit); i++) {
2119 ShenandoahHeapRegion *r = _ordered_regions->get(i);
2120 if (r->is_trash()) {
2121 decrease_used(r->used());
2122 r->recycle();
2123 _free_regions->add_region(r);
2124 count++;
2125 }
2126 }
2127 }
2128
2129 void ShenandoahHeap::recycle_trash() {
2130 // lock is not reentrable, check we don't have it
2131 assert_heaplock_not_owned_by_current_thread();
2132
2133 size_t bytes_reclaimed = 0;
2134
2135 if (UseShenandoahMatrix) {
2136 // The complication for matrix cleanup is that we want the batched update
2137 // to alleviate costs. We also cannot add regions to freeset until matrix
2138 // is clean, otherwise we race with the actual allocations.
2139
2140 size_t count = 0;
2141 for (size_t i = 0; i < num_regions(); i++) {
2142 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2143 if (r->is_trash()) {
2144 ShenandoahHeapLocker locker(lock());
2145 if (r->is_trash()) {
2146 bytes_reclaimed += r->used();
2147 decrease_used(r->used());
2148 r->recycle_no_matrix();
2149 _recycled_regions[count++] = r->region_number();
2150 }
2151 }
2152 SpinPause(); // allow allocators to barge the lock
2153 }
2154
2155 connection_matrix()->clear_batched(_recycled_regions, count);
2156
2157 {
2158 ShenandoahHeapLocker locker(lock());
2159 for (size_t i = 0; i < count; i++) {
2160 ShenandoahHeapRegion *r = _ordered_regions->get(_recycled_regions[i]);
2161 _free_regions->add_region(r);
2162 }
2163 }
2164
2165 } else {
2166 for (size_t i = 0; i < num_regions(); i++) {
2167 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2168 if (r->is_trash()) {
2169 ShenandoahHeapLocker locker(lock());
2170 if (r->is_trash()) {
2171 bytes_reclaimed += r->used();
2172 decrease_used(r->used());
2173 r->recycle();
2174 _free_regions->add_region(r);
2175 }
2176 }
2177 SpinPause(); // allow allocators to barge the lock
2178 }
2179 }
2180
2181 _shenandoah_policy->record_bytes_reclaimed(bytes_reclaimed);
2182 }
2183
2184 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2185 print_on(st);
2186 print_heap_regions_on(st);
2187 }
2188
2189 bool ShenandoahHeap::commit_bitmaps(ShenandoahHeapRegion* r) {
2190 size_t len = _bitmap_words_per_region * HeapWordSize;
2191 size_t off = r->region_number() * _bitmap_words_per_region;
2192 if (!os::commit_memory((char*)(_bitmap0_region.start() + off), len, false)) {
2193 return false;
2194 }
2195 if (!os::commit_memory((char*)(_bitmap1_region.start() + off), len, false)) {
2196 return false;
2197 }
2198 return true;
2199 }
2200
2201 bool ShenandoahHeap::uncommit_bitmaps(ShenandoahHeapRegion* r) {
2202 size_t len = _bitmap_words_per_region * HeapWordSize;
2203 size_t off = r->region_number() * _bitmap_words_per_region;
2204 if (!os::uncommit_memory((char*)(_bitmap0_region.start() + off), len)) {
2205 return false;
2206 }
2207 if (!os::uncommit_memory((char*)(_bitmap1_region.start() + off), len)) {
2208 return false;
2209 }
2210 return true;
2211 }