1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
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_implementation/shared/gcTimer.hpp"
28 #include "gc_implementation/shenandoah/shenandoahGCTraceTime.hpp"
29 #include "gc_implementation/shared/parallelCleaning.hpp"
30
31 #include "gc_implementation/shenandoah/shenandoahBrooksPointer.hpp"
32 #include "gc_implementation/shenandoah/shenandoahAllocTracker.hpp"
33 #include "gc_implementation/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.hpp"
37 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.inline.hpp"
38 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp"
39 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp"
40 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
41 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
42 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp"
43 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp"
44 #include "gc_implementation/shenandoah/shenandoahMarkCompact.hpp"
45 #include "gc_implementation/shenandoah/shenandoahMarkingContext.inline.hpp"
46 #include "gc_implementation/shenandoah/shenandoahMonitoringSupport.hpp"
47 #include "gc_implementation/shenandoah/shenandoahMetrics.hpp"
48 #include "gc_implementation/shenandoah/shenandoahOopClosures.inline.hpp"
49 #include "gc_implementation/shenandoah/shenandoahPacer.hpp"
50 #include "gc_implementation/shenandoah/shenandoahPacer.inline.hpp"
51 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp"
52 #include "gc_implementation/shenandoah/shenandoahUtils.hpp"
53 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp"
54 #include "gc_implementation/shenandoah/shenandoahCodeRoots.hpp"
55 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp"
56 #include "gc_implementation/shenandoah/shenandoahWorkGroup.hpp"
57 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp"
58 #include "gc_implementation/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
59 #include "gc_implementation/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
60 #include "gc_implementation/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
61 #include "gc_implementation/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
62 #include "gc_implementation/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
63
64 #include "memory/metaspace.hpp"
65 #include "runtime/vmThread.hpp"
66 #include "services/mallocTracker.hpp"
67
68 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
69
70 #ifdef ASSERT
71 template <class T>
72 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
73 T o = oopDesc::load_heap_oop(p);
74 if (! oopDesc::is_null(o)) {
75 oop obj = oopDesc::decode_heap_oop_not_null(o);
76 shenandoah_assert_not_forwarded(p, obj);
77 }
78 }
79
80 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
81 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
82 #endif
83
84 class ShenandoahPretouchTask : public AbstractGangTask {
85 private:
86 ShenandoahRegionIterator _regions;
87 const size_t _bitmap_size;
88 const size_t _page_size;
89 char* _bitmap_base;
90 public:
91 ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
92 AbstractGangTask("Shenandoah PreTouch"),
93 _bitmap_size(bitmap_size),
94 _page_size(page_size),
95 _bitmap_base(bitmap_base) {}
96
97 virtual void work(uint worker_id) {
98 ShenandoahHeapRegion* r = _regions.next();
99 while (r != NULL) {
100 os::pretouch_memory((char*) r->bottom(), (char*) r->end());
101
102 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
103 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
104 assert (end <= _bitmap_size, err_msg("end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size));
105
106 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end);
107
108 r = _regions.next();
109 }
110 }
111 };
112
113 jint ShenandoahHeap::initialize() {
114 CollectedHeap::pre_initialize();
115
116 ShenandoahBrooksPointer::initial_checks();
117
118 initialize_heuristics();
119
120 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
121 size_t max_byte_size = collector_policy()->max_heap_byte_size();
122 size_t heap_alignment = collector_policy()->heap_alignment();
123
124 if (ShenandoahAlwaysPreTouch) {
125 // Enabled pre-touch means the entire heap is committed right away.
126 init_byte_size = max_byte_size;
127 }
128
129 Universe::check_alignment(max_byte_size,
130 ShenandoahHeapRegion::region_size_bytes(),
131 "shenandoah heap");
132 Universe::check_alignment(init_byte_size,
133 ShenandoahHeapRegion::region_size_bytes(),
134 "shenandoah heap");
135
136 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
137 heap_alignment);
138
139 _reserved.set_word_size(0);
140 _reserved.set_start((HeapWord*)heap_rs.base());
141 _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size()));
142
143 set_barrier_set(new ShenandoahBarrierSet(this));
144 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
145
146 _num_regions = ShenandoahHeapRegion::region_count();
147
148 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
149 num_committed_regions = MIN2(num_committed_regions, _num_regions);
150 assert(num_committed_regions <= _num_regions, "sanity");
151
152 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
153 _committed = _initial_size;
154
155 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
156 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
157 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
158 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
159 }
160
161 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
162 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
163
164 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
165 _free_set = new ShenandoahFreeSet(this, _num_regions);
166
167 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
168
169 if (ShenandoahPacing) {
170 _pacer = new ShenandoahPacer(this);
171 _pacer->setup_for_idle();
172 } else {
173 _pacer = NULL;
174 }
175
176 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
177 err_msg("misaligned heap: " PTR_FORMAT, p2i(base())));
178
179 // The call below uses stuff (the SATB* things) that are in G1, but probably
180 // belong into a shared location.
181 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
182 SATB_Q_FL_lock,
183 20 /*G1SATBProcessCompletedThreshold */,
184 Shared_SATB_Q_lock);
185
186 // Reserve space for prev and next bitmap.
187 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
188 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
189 _bitmap_size = align_size_up(_bitmap_size, bitmap_page_size);
190 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
191
192 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
193
194 guarantee(bitmap_bytes_per_region != 0,
195 err_msg("Bitmap bytes per region should not be zero"));
196 guarantee(is_power_of_2(bitmap_bytes_per_region),
197 err_msg("Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region));
198
199 if (bitmap_page_size > bitmap_bytes_per_region) {
200 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
201 _bitmap_bytes_per_slice = bitmap_page_size;
202 } else {
203 _bitmap_regions_per_slice = 1;
204 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
205 }
206
207 guarantee(_bitmap_regions_per_slice >= 1,
208 err_msg("Should have at least one region per slice: " SIZE_FORMAT,
209 _bitmap_regions_per_slice));
210
211 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
212 err_msg("Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
213 _bitmap_bytes_per_slice, bitmap_page_size));
214
215 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
216 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
217 _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
218
219 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
220 align_size_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
221 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
222 os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
223 "couldn't allocate initial bitmap");
224
225 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
226
227 if (ShenandoahVerify) {
228 ReservedSpace verify_bitmap(_bitmap_size, page_size);
229 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
230 "couldn't allocate verification bitmap");
231 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
232 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
233 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
234 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
235 }
236
237 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
238
239 {
240 ShenandoahHeapLocker locker(lock());
241 for (size_t i = 0; i < _num_regions; i++) {
242 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
243 (HeapWord*) pgc_rs.base() + reg_size_words * i,
244 reg_size_words,
245 i,
246 i < num_committed_regions);
247
248 _marking_context->initialize_top_at_mark_start(r);
249 _regions[i] = r;
250 assert(!collection_set()->is_in(i), "New region should not be in collection set");
251 }
252
253 // Initialize to complete
254 _marking_context->mark_complete();
255
256 _free_set->rebuild();
257 }
258
259 if (ShenandoahAlwaysPreTouch) {
260 assert (!AlwaysPreTouch, "Should have been overridden");
261
262 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
263 // before initialize() below zeroes it with initializing thread. For any given region,
264 // we touch the region and the corresponding bitmaps from the same thread.
265 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
266
267 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
268 _num_regions, page_size);
269 ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
270 _workers->run_task(&cl);
271 }
272
273 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
274 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
275 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
276 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
277 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
278
279 _monitoring_support = new ShenandoahMonitoringSupport(this);
280
281 _phase_timings = new ShenandoahPhaseTimings();
282
283 if (ShenandoahAllocationTrace) {
284 _alloc_tracker = new ShenandoahAllocTracker();
285 }
286
287 ShenandoahStringDedup::initialize();
288
289 _control_thread = new ShenandoahControlThread();
290
291 ShenandoahCodeRoots::initialize();
292
293 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
294 for (uint worker = 0; worker < _max_workers; worker++) {
295 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
296 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
297 }
298
299 return JNI_OK;
300 }
301
302 #ifdef _MSC_VER
303 #pragma warning( push )
304 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
305 #endif
306
307 void ShenandoahHeap::initialize_heuristics() {
308 if (ShenandoahGCHeuristics != NULL) {
309 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
310 _heuristics = new ShenandoahAggressiveHeuristics();
311 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
312 _heuristics = new ShenandoahStaticHeuristics();
313 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
314 _heuristics = new ShenandoahAdaptiveHeuristics();
315 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
316 _heuristics = new ShenandoahPassiveHeuristics();
317 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
318 _heuristics = new ShenandoahCompactHeuristics();
319 } else {
320 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
321 }
322
323 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
324 vm_exit_during_initialization(
325 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
326 _heuristics->name()));
327 }
328 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
329 vm_exit_during_initialization(
330 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
331 _heuristics->name()));
332 }
333 log_info(gc, init)("Shenandoah heuristics: %s",
334 _heuristics->name());
335 } else {
336 ShouldNotReachHere();
337 }
338 }
339
340 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
341 SharedHeap(policy),
342 _shenandoah_policy(policy),
343 _regions(NULL),
344 _free_set(NULL),
345 _collection_set(NULL),
346 _update_refs_iterator(this),
347 _bytes_allocated_since_gc_start(0),
348 _max_workers((uint)MAX2(ConcGCThreads, ParallelGCThreads)),
349 _ref_processor(NULL),
350 _marking_context(NULL),
351 _aux_bit_map(),
352 _verifier(NULL),
353 _pacer(NULL),
354 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
355 _phase_timings(NULL),
356 _alloc_tracker(NULL)
357 {
358 log_info(gc, init)("GC threads: " UINTX_FORMAT " parallel, " UINTX_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
359 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
360
361 _scm = new ShenandoahConcurrentMark();
362 _full_gc = new ShenandoahMarkCompact();
363 _used = 0;
364
365 _max_workers = MAX2(_max_workers, 1U);
366 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
367 /* are_GC_task_threads */true,
368 /* are_ConcurrentGC_threads */false);
369 if (_workers == NULL) {
370 vm_exit_during_initialization("Failed necessary allocation.");
371 } else {
372 _workers->initialize_workers();
373 }
374 }
375
376 #ifdef _MSC_VER
377 #pragma warning( pop )
378 #endif
379
380 class ShenandoahResetBitmapTask : public AbstractGangTask {
381 private:
382 ShenandoahRegionIterator _regions;
383
384 public:
385 ShenandoahResetBitmapTask() :
386 AbstractGangTask("Parallel Reset Bitmap Task") {}
387
388 void work(uint worker_id) {
389 ShenandoahHeapRegion* region = _regions.next();
390 ShenandoahHeap* heap = ShenandoahHeap::heap();
391 ShenandoahMarkingContext* const ctx = heap->marking_context();
392 while (region != NULL) {
393 if (heap->is_bitmap_slice_committed(region)) {
394 ctx->clear_bitmap(region);
395 }
396 region = _regions.next();
397 }
398 }
399 };
400
401 void ShenandoahHeap::reset_mark_bitmap() {
402 assert_gc_workers(_workers->active_workers());
403 mark_incomplete_marking_context();
404
405 ShenandoahResetBitmapTask task;
406 _workers->run_task(&task);
407 }
408
409 void ShenandoahHeap::print_on(outputStream* st) const {
410 st->print_cr("Shenandoah Heap");
411 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
412 capacity() / K, committed() / K, used() / K);
413 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
414 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
415
416 st->print("Status: ");
417 if (has_forwarded_objects()) st->print("has forwarded objects, ");
418 if (is_concurrent_mark_in_progress()) st->print("marking, ");
419 if (is_evacuation_in_progress()) st->print("evacuating, ");
420 if (is_update_refs_in_progress()) st->print("updating refs, ");
421 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
422 if (is_full_gc_in_progress()) st->print("full gc, ");
423 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
424
425 if (cancelled_gc()) {
426 st->print("cancelled");
427 } else {
428 st->print("not cancelled");
429 }
430 st->cr();
431
432 st->print_cr("Reserved region:");
433 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
434 p2i(reserved_region().start()),
435 p2i(reserved_region().end()));
436
437 st->cr();
438 MetaspaceAux::print_on(st);
439
440 if (Verbose) {
441 print_heap_regions_on(st);
442 }
443 }
444
445 class ShenandoahInitGCLABClosure : public ThreadClosure {
446 public:
447 void do_thread(Thread* thread) {
448 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
449 thread->gclab().initialize(true);
450 }
451 }
452 };
453
454 void ShenandoahHeap::post_initialize() {
455 if (UseTLAB) {
456 MutexLocker ml(Threads_lock);
457
458 ShenandoahInitGCLABClosure init_gclabs;
459 Threads::java_threads_do(&init_gclabs);
460 _workers->threads_do(&init_gclabs);
461 }
462
463 _scm->initialize(_max_workers);
464 _full_gc->initialize(_gc_timer);
465
466 ref_processing_init();
467
468 _heuristics->initialize();
469 }
470
471 size_t ShenandoahHeap::used() const {
472 OrderAccess::acquire();
473 return (size_t) _used;
474 }
475
476 size_t ShenandoahHeap::committed() const {
477 OrderAccess::acquire();
478 return _committed;
479 }
480
481 void ShenandoahHeap::increase_committed(size_t bytes) {
482 assert_heaplock_or_safepoint();
483 _committed += bytes;
484 }
485
486 void ShenandoahHeap::decrease_committed(size_t bytes) {
487 assert_heaplock_or_safepoint();
488 _committed -= bytes;
489 }
490
491 void ShenandoahHeap::increase_used(size_t bytes) {
492 Atomic::add(bytes, &_used);
493 }
494
495 void ShenandoahHeap::set_used(size_t bytes) {
496 OrderAccess::release_store_fence(&_used, bytes);
497 }
498
499 void ShenandoahHeap::decrease_used(size_t bytes) {
500 assert(used() >= bytes, "never decrease heap size by more than we've left");
501 Atomic::add(-(jlong)bytes, &_used);
502 }
503
504 void ShenandoahHeap::increase_allocated(size_t bytes) {
505 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
506 }
507
508 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
509 size_t bytes = words * HeapWordSize;
510 if (!waste) {
511 increase_used(bytes);
512 }
513 increase_allocated(bytes);
514 if (ShenandoahPacing) {
515 control_thread()->pacing_notify_alloc(words);
516 if (waste) {
517 pacer()->claim_for_alloc(words, true);
518 }
519 }
520 }
521
522 size_t ShenandoahHeap::capacity() const {
523 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
524 }
525
526 size_t ShenandoahHeap::max_capacity() const {
527 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
528 }
529
530 size_t ShenandoahHeap::initial_capacity() const {
531 return _initial_size;
532 }
533
534 bool ShenandoahHeap::is_in(const void* p) const {
535 HeapWord* heap_base = (HeapWord*) base();
536 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
537 return p >= heap_base && p < last_region_end;
538 }
539
540 void ShenandoahHeap::op_uncommit(double shrink_before) {
541 assert (ShenandoahUncommit, "should be enabled");
542
543 size_t count = 0;
544 for (size_t i = 0; i < num_regions(); i++) {
545 ShenandoahHeapRegion* r = get_region(i);
546 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
547 ShenandoahHeapLocker locker(lock());
548 if (r->is_empty_committed()) {
549 r->make_uncommitted();
550 count++;
551 }
552 }
553 SpinPause(); // allow allocators to take the lock
554 }
555
556 if (count > 0) {
557 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
558 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
559 _control_thread->notify_heap_changed();
560 }
561 }
562
563 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
564 // Retain tlab and allocate object in shared space if
565 // the amount free in the tlab is too large to discard.
566 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
567 thread->gclab().record_slow_allocation(size);
568 return NULL;
569 }
570
571 // Discard gclab and allocate a new one.
572 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
573 size_t new_gclab_size = thread->gclab().compute_size(size);
574
575 thread->gclab().clear_before_allocation();
576
577 if (new_gclab_size == 0) {
578 return NULL;
579 }
580
581 // Allocated object should fit in new GCLAB, and new_gclab_size should be larger than min
582 size_t min_size = MAX2(size + ThreadLocalAllocBuffer::alignment_reserve(), ThreadLocalAllocBuffer::min_size());
583 new_gclab_size = MAX2(new_gclab_size, min_size);
584
585 // Allocate a new GCLAB...
586 size_t actual_size = 0;
587 HeapWord* obj = allocate_new_gclab(min_size, new_gclab_size, &actual_size);
588
589 if (obj == NULL) {
590 return NULL;
591 }
592
593 assert (size <= actual_size, "allocation should fit");
594
595 if (ZeroTLAB) {
596 // ..and clear it.
597 Copy::zero_to_words(obj, actual_size);
598 } else {
599 // ...and zap just allocated object.
600 #ifdef ASSERT
601 // Skip mangling the space corresponding to the object header to
602 // ensure that the returned space is not considered parsable by
603 // any concurrent GC thread.
604 size_t hdr_size = oopDesc::header_size();
605 Copy::fill_to_words(obj + hdr_size, actual_size - hdr_size, badHeapWordVal);
606 #endif // ASSERT
607 }
608 thread->gclab().fill(obj, obj + size, actual_size);
609 return obj;
610 }
611
612 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
613 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(word_size);
614 return allocate_memory(req);
615 }
616
617 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
618 size_t word_size,
619 size_t* actual_size) {
620 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
621 HeapWord* res = allocate_memory(req);
622 if (res != NULL) {
623 *actual_size = req.actual_size();
624 } else {
625 *actual_size = 0;
626 }
627 return res;
628 }
629
630 ShenandoahHeap* ShenandoahHeap::heap() {
631 CollectedHeap* heap = Universe::heap();
632 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
633 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
634 return (ShenandoahHeap*) heap;
635 }
636
637 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
638 CollectedHeap* heap = Universe::heap();
639 return (ShenandoahHeap*) heap;
640 }
641
642 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
643 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
644
645 intptr_t pacer_epoch = 0;
646 bool in_new_region = false;
647 HeapWord* result = NULL;
648
649 if (req.is_mutator_alloc()) {
650 if (ShenandoahPacing) {
651 pacer()->pace_for_alloc(req.size());
652 pacer_epoch = pacer()->epoch();
653 }
654
655 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
656 result = allocate_memory_under_lock(req, in_new_region);
657 }
658
659 // Allocation failed, block until control thread reacted, then retry allocation.
660 //
661 // It might happen that one of the threads requesting allocation would unblock
662 // way later after GC happened, only to fail the second allocation, because
663 // other threads have already depleted the free storage. In this case, a better
664 // strategy is to try again, as long as GC makes progress.
665 //
666 // Then, we need to make sure the allocation was retried after at least one
667 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
668
669 size_t tries = 0;
670
671 while (result == NULL && _progress_last_gc.is_set()) {
672 tries++;
673 control_thread()->handle_alloc_failure(req.size());
674 result = allocate_memory_under_lock(req, in_new_region);
675 }
676
677 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
678 tries++;
679 control_thread()->handle_alloc_failure(req.size());
680 result = allocate_memory_under_lock(req, in_new_region);
681 }
682
683 } else {
684 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
685 result = allocate_memory_under_lock(req, in_new_region);
686 // Do not call handle_alloc_failure() here, because we cannot block.
687 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
688 }
689
690 if (in_new_region) {
691 control_thread()->notify_heap_changed();
692 }
693
694 if (result != NULL) {
695 size_t requested = req.size();
696 size_t actual = req.actual_size();
697
698 assert (req.is_lab_alloc() || (requested == actual),
699 err_msg("Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
700 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual));
701
702 if (req.is_mutator_alloc()) {
703 notify_mutator_alloc_words(actual, false);
704
705 // If we requested more than we were granted, give the rest back to pacer.
706 // This only matters if we are in the same pacing epoch: do not try to unpace
707 // over the budget for the other phase.
708 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
709 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
710 }
711 } else {
712 increase_used(actual*HeapWordSize);
713 }
714 }
715
716 return result;
717 }
718
719 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
720 ShenandoahHeapLocker locker(lock());
721 return _free_set->allocate(req, in_new_region);
722 }
723
724 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
725 bool* gc_overhead_limit_was_exceeded) {
726 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size + ShenandoahBrooksPointer::word_size());
727 HeapWord* filler = allocate_memory(req);
728 HeapWord* result = filler + ShenandoahBrooksPointer::word_size();
729 if (filler != NULL) {
730 ShenandoahBrooksPointer::initialize(oop(result));
731
732 assert(! in_collection_set(result), "never allocate in targetted region");
733 return result;
734 } else {
735 return NULL;
736 }
737 }
738
739 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
740 private:
741 ShenandoahHeap* _heap;
742 Thread* _thread;
743 public:
744 ShenandoahEvacuateUpdateRootsClosure() :
745 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
746 }
747
748 private:
749 template <class T>
750 void do_oop_work(T* p) {
751 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
752
753 T o = oopDesc::load_heap_oop(p);
754 if (! oopDesc::is_null(o)) {
755 oop obj = oopDesc::decode_heap_oop_not_null(o);
756 if (_heap->in_collection_set(obj)) {
757 shenandoah_assert_marked(p, obj);
758 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
759 if (oopDesc::unsafe_equals(resolved, obj)) {
760 bool evac;
761 resolved = _heap->evacuate_object(obj, _thread, evac);
762 }
763 oopDesc::encode_store_heap_oop(p, resolved);
764 }
765 }
766 }
767
768 public:
769 void do_oop(oop* p) {
770 do_oop_work(p);
771 }
772 void do_oop(narrowOop* p) {
773 do_oop_work(p);
774 }
775 };
776
777 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
778 private:
779 ShenandoahHeap* const _heap;
780 Thread* const _thread;
781 public:
782 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
783 _heap(heap), _thread(Thread::current()) {}
784
785 void do_object(oop p) {
786 shenandoah_assert_marked(NULL, p);
787 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
788 bool evac;
789 _heap->evacuate_object(p, _thread, evac);
790 }
791 }
792 };
793
794 class ShenandoahEvacuationTask : public AbstractGangTask {
795 private:
796 ShenandoahHeap* const _sh;
797 ShenandoahCollectionSet* const _cs;
798 bool _concurrent;
799 public:
800 ShenandoahEvacuationTask(ShenandoahHeap* sh,
801 ShenandoahCollectionSet* cs,
802 bool concurrent) :
803 AbstractGangTask("Parallel Evacuation Task"),
804 _sh(sh),
805 _cs(cs),
806 _concurrent(concurrent)
807 {}
808
809 void work(uint worker_id) {
810 ShenandoahEvacOOMScope oom_evac_scope;
811 if (_concurrent) {
812 ShenandoahConcurrentWorkerSession worker_session(worker_id);
813 do_work();
814 } else {
815 ShenandoahParallelWorkerSession worker_session(worker_id);
816 do_work();
817 }
818 }
819
820 private:
821 void do_work() {
822 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
823 ShenandoahHeapRegion* r;
824 while ((r =_cs->claim_next()) != NULL) {
825 assert(r->has_live(), "all-garbage regions are reclaimed early");
826 _sh->marked_object_iterate(r, &cl);
827
828 if (ShenandoahPacing) {
829 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
830 }
831
832 if (_sh->cancelled_gc()) {
833 break;
834 }
835 }
836 }
837 };
838
839 void ShenandoahHeap::trash_cset_regions() {
840 ShenandoahHeapLocker locker(lock());
841
842 ShenandoahCollectionSet* set = collection_set();
843 ShenandoahHeapRegion* r;
844 set->clear_current_index();
845 while ((r = set->next()) != NULL) {
846 r->make_trash();
847 }
848 collection_set()->clear();
849 }
850
851 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
852 st->print_cr("Heap Regions:");
853 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
854 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
855 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
856
857 for (size_t i = 0; i < num_regions(); i++) {
858 get_region(i)->print_on(st);
859 }
860 }
861
862 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
863 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
864
865 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
866 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
867 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
868 size_t index = start->region_number() + required_regions - 1;
869
870 assert(!start->has_live(), "liveness must be zero");
871
872 for(size_t i = 0; i < required_regions; i++) {
873 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
874 // as it expects that every region belongs to a humongous region starting with a humongous start region.
875 ShenandoahHeapRegion* region = get_region(index --);
876
877 assert(region->is_humongous(), "expect correct humongous start or continuation");
878 assert(!region->is_cset(), "Humongous region should not be in collection set");
879
880 region->make_trash_immediate();
881 }
882 }
883
884 class ShenandoahRetireGCLABClosure : public ThreadClosure {
885 private:
886 bool _retire;
887 public:
888 ShenandoahRetireGCLABClosure(bool retire) : _retire(retire) {};
889
890 void do_thread(Thread* thread) {
891 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
892 thread->gclab().make_parsable(_retire);
893 }
894 };
895
896 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
897 if (UseTLAB) {
898 CollectedHeap::ensure_parsability(retire_tlabs);
899 ShenandoahRetireGCLABClosure cl(retire_tlabs);
900 Threads::java_threads_do(&cl);
901 _workers->threads_do(&cl);
902 }
903 }
904
905 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
906 private:
907 ShenandoahRootEvacuator* _rp;
908
909 public:
910 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
911 AbstractGangTask("Shenandoah evacuate and update roots"),
912 _rp(rp) {}
913
914 void work(uint worker_id) {
915 ShenandoahParallelWorkerSession worker_session(worker_id);
916 ShenandoahEvacOOMScope oom_evac_scope;
917 ShenandoahEvacuateUpdateRootsClosure cl;
918
919 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
920 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
921 }
922 };
923
924 void ShenandoahHeap::evacuate_and_update_roots() {
925 COMPILER2_PRESENT(DerivedPointerTable::clear());
926
927 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
928
929 {
930 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
931 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
932 workers()->run_task(&roots_task);
933 }
934
935 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
936 }
937
938 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
939 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
940
941 CodeBlobToOopClosure blobsCl(cl, false);
942 CLDToOopClosure cldCl(cl);
943
944 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
945 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
946 }
947
948 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
949 // Returns size in bytes
950 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
951 }
952
953 size_t ShenandoahHeap::max_tlab_size() const {
954 // Returns size in words
955 return ShenandoahHeapRegion::max_tlab_size_words();
956 }
957
958 class ShenandoahResizeGCLABClosure : public ThreadClosure {
959 public:
960 void do_thread(Thread* thread) {
961 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
962 thread->gclab().resize();
963 }
964 };
965
966 void ShenandoahHeap::resize_all_tlabs() {
967 CollectedHeap::resize_all_tlabs();
968
969 ShenandoahResizeGCLABClosure cl;
970 Threads::java_threads_do(&cl);
971 _workers->threads_do(&cl);
972 }
973
974 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
975 public:
976 void do_thread(Thread* thread) {
977 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
978 thread->gclab().accumulate_statistics();
979 thread->gclab().initialize_statistics();
980 }
981 };
982
983 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
984 ShenandoahAccumulateStatisticsGCLABClosure cl;
985 Threads::java_threads_do(&cl);
986 _workers->threads_do(&cl);
987 }
988
989 void ShenandoahHeap::collect(GCCause::Cause cause) {
990 _control_thread->request_gc(cause);
991 }
992
993 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
994 //assert(false, "Shouldn't need to do full collections");
995 }
996
997 CollectorPolicy* ShenandoahHeap::collector_policy() const {
998 return _shenandoah_policy;
999 }
1000
1001 void ShenandoahHeap::resize_tlabs() {
1002 CollectedHeap::resize_all_tlabs();
1003 }
1004
1005 void ShenandoahHeap::accumulate_statistics_tlabs() {
1006 CollectedHeap::accumulate_statistics_all_tlabs();
1007 }
1008
1009 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1010 Space* sp = heap_region_containing(addr);
1011 if (sp != NULL) {
1012 return sp->block_start(addr);
1013 }
1014 return NULL;
1015 }
1016
1017 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1018 Space* sp = heap_region_containing(addr);
1019 assert(sp != NULL, "block_size of address outside of heap");
1020 return sp->block_size(addr);
1021 }
1022
1023 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1024 Space* sp = heap_region_containing(addr);
1025 return sp->block_is_obj(addr);
1026 }
1027
1028 jlong ShenandoahHeap::millis_since_last_gc() {
1029 double v = heuristics()->time_since_last_gc() * 1000;
1030 assert(0 <= v && v <= max_jlong, err_msg("value should fit: %f", v));
1031 return (jlong)v;
1032 }
1033
1034 void ShenandoahHeap::prepare_for_verify() {
1035 if (SafepointSynchronize::is_at_safepoint()) {
1036 make_parsable(false);
1037 }
1038 }
1039
1040 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1041 workers()->print_worker_threads_on(st);
1042 if (ShenandoahStringDedup::is_enabled()) {
1043 ShenandoahStringDedup::print_worker_threads_on(st);
1044 }
1045 }
1046
1047 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1048 workers()->threads_do(tcl);
1049 if (ShenandoahStringDedup::is_enabled()) {
1050 ShenandoahStringDedup::threads_do(tcl);
1051 }
1052 }
1053
1054 void ShenandoahHeap::print_tracing_info() const {
1055 if (PrintGC || TraceGen0Time || TraceGen1Time) {
1056 ResourceMark rm;
1057 outputStream* out = gclog_or_tty;
1058 phase_timings()->print_on(out);
1059
1060 out->cr();
1061 out->cr();
1062
1063 shenandoah_policy()->print_gc_stats(out);
1064
1065 out->cr();
1066 out->cr();
1067
1068 if (ShenandoahPacing) {
1069 pacer()->print_on(out);
1070 }
1071
1072 out->cr();
1073 out->cr();
1074
1075 if (ShenandoahAllocationTrace) {
1076 assert(alloc_tracker() != NULL, "Must be");
1077 alloc_tracker()->print_on(out);
1078 } else {
1079 out->print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1080 }
1081 }
1082 }
1083
1084 void ShenandoahHeap::verify(bool silent, VerifyOption vo) {
1085 if (ShenandoahSafepoint::is_at_shenandoah_safepoint() || ! UseTLAB) {
1086 if (ShenandoahVerify) {
1087 verifier()->verify_generic(vo);
1088 } else {
1089 // TODO: Consider allocating verification bitmaps on demand,
1090 // and turn this on unconditionally.
1091 }
1092 }
1093 }
1094 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1095 return _free_set->capacity();
1096 }
1097
1098 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1099 private:
1100 MarkBitMap* _bitmap;
1101 Stack<oop,mtGC>* _oop_stack;
1102
1103 template <class T>
1104 void do_oop_work(T* p) {
1105 T o = oopDesc::load_heap_oop(p);
1106 if (!oopDesc::is_null(o)) {
1107 oop obj = oopDesc::decode_heap_oop_not_null(o);
1108 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1109 assert(obj->is_oop(), "must be a valid oop");
1110 if (!_bitmap->isMarked((HeapWord*) obj)) {
1111 _bitmap->mark((HeapWord*) obj);
1112 _oop_stack->push(obj);
1113 }
1114 }
1115 }
1116 public:
1117 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1118 _bitmap(bitmap), _oop_stack(oop_stack) {}
1119 void do_oop(oop* p) { do_oop_work(p); }
1120 void do_oop(narrowOop* p) { do_oop_work(p); }
1121 };
1122
1123 /*
1124 * This is public API, used in preparation of object_iterate().
1125 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1126 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1127 * control, we call SH::make_parsable().
1128 */
1129 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1130 // No-op.
1131 }
1132
1133 /*
1134 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1135 *
1136 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1137 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1138 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1139 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1140 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1141 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1142 * wiped the bitmap in preparation for next marking).
1143 *
1144 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1145 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1146 * is allowed to report dead objects, but is not required to do so.
1147 */
1148 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1149 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1150 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1151 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1152 return;
1153 }
1154
1155 // Reset bitmap
1156 _aux_bit_map.clear();
1157
1158 Stack<oop,mtGC> oop_stack;
1159
1160 // First, we process all GC roots. This populates the work stack with initial objects.
1161 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1162 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1163 CLDToOopClosure clds(&oops, false);
1164 CodeBlobToOopClosure blobs(&oops, false);
1165 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1166
1167 // Work through the oop stack to traverse heap.
1168 while (! oop_stack.is_empty()) {
1169 oop obj = oop_stack.pop();
1170 assert(obj->is_oop(), "must be a valid oop");
1171 cl->do_object(obj);
1172 obj->oop_iterate(&oops);
1173 }
1174
1175 assert(oop_stack.is_empty(), "should be empty");
1176
1177 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1178 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1179 }
1180 }
1181
1182 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1183 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1184 object_iterate(cl);
1185 }
1186
1187 void ShenandoahHeap::oop_iterate(ExtendedOopClosure* cl) {
1188 ObjectToOopClosure cl2(cl);
1189 object_iterate(&cl2);
1190 }
1191
1192 class ShenandoahSpaceClosureRegionClosure: public ShenandoahHeapRegionClosure {
1193 SpaceClosure* _cl;
1194 public:
1195 ShenandoahSpaceClosureRegionClosure(SpaceClosure* cl) : _cl(cl) {}
1196 void heap_region_do(ShenandoahHeapRegion* r) {
1197 _cl->do_space(r);
1198 }
1199 };
1200
1201 void ShenandoahHeap::space_iterate(SpaceClosure* cl) {
1202 ShenandoahSpaceClosureRegionClosure blk(cl);
1203 heap_region_iterate(&blk);
1204 }
1205
1206 Space* ShenandoahHeap::space_containing(const void* oop) const {
1207 Space* res = heap_region_containing(oop);
1208 return res;
1209 }
1210
1211 void ShenandoahHeap::gc_prologue(bool b) {
1212 Unimplemented();
1213 }
1214
1215 void ShenandoahHeap::gc_epilogue(bool b) {
1216 Unimplemented();
1217 }
1218
1219 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1220 for (size_t i = 0; i < num_regions(); i++) {
1221 ShenandoahHeapRegion* current = get_region(i);
1222 blk->heap_region_do(current);
1223 }
1224 }
1225
1226 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1227 private:
1228 ShenandoahHeap* const _heap;
1229 ShenandoahHeapRegionClosure* const _blk;
1230
1231 char _pad0[DEFAULT_CACHE_LINE_SIZE];
1232 volatile jint _index;
1233 char _pad1[DEFAULT_CACHE_LINE_SIZE];
1234
1235 public:
1236 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1237 AbstractGangTask("Parallel Region Task"),
1238 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1239
1240 void work(uint worker_id) {
1241 jint stride = (jint)ShenandoahParallelRegionStride;
1242
1243 jint max = (jint)_heap->num_regions();
1244 while (_index < max) {
1245 jint cur = Atomic::add(stride, &_index) - stride;
1246 jint start = cur;
1247 jint end = MIN2(cur + stride, max);
1248 if (start >= max) break;
1249
1250 for (jint i = cur; i < end; i++) {
1251 ShenandoahHeapRegion* current = _heap->get_region((size_t)i);
1252 _blk->heap_region_do(current);
1253 }
1254 }
1255 }
1256 };
1257
1258 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1259 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1260 if (num_regions() > ShenandoahParallelRegionStride) {
1261 ShenandoahParallelHeapRegionTask task(blk);
1262 workers()->run_task(&task);
1263 } else {
1264 heap_region_iterate(blk);
1265 }
1266 }
1267
1268 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1269 private:
1270 ShenandoahMarkingContext* const _ctx;
1271 public:
1272 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1273
1274 void heap_region_do(ShenandoahHeapRegion* r) {
1275 if (r->is_active()) {
1276 r->clear_live_data();
1277 _ctx->capture_top_at_mark_start(r);
1278 } else {
1279 assert(!r->has_live(),
1280 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number()));
1281 assert(_ctx->top_at_mark_start(r) == r->top(),
1282 err_msg("Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()));
1283 }
1284 }
1285
1286 bool is_thread_safe() { return true; }
1287 };
1288
1289 void ShenandoahHeap::op_init_mark() {
1290 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1291 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1292
1293 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1294 assert(!marking_context()->is_complete(), "should not be complete");
1295
1296 if (ShenandoahVerify) {
1297 verifier()->verify_before_concmark();
1298 }
1299
1300 {
1301 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1302 accumulate_statistics_tlabs();
1303 }
1304
1305 if (VerifyBeforeGC) {
1306 Universe::verify();
1307 }
1308
1309 set_concurrent_mark_in_progress(true);
1310 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1311 if (UseTLAB) {
1312 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1313 make_parsable(true);
1314 }
1315
1316 {
1317 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1318 ShenandoahClearLivenessClosure clc;
1319 parallel_heap_region_iterate(&clc);
1320 }
1321
1322 // Make above changes visible to worker threads
1323 OrderAccess::fence();
1324
1325 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1326
1327 if (UseTLAB) {
1328 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1329 resize_tlabs();
1330 }
1331
1332 if (ShenandoahPacing) {
1333 pacer()->setup_for_mark();
1334 }
1335 }
1336
1337 void ShenandoahHeap::op_mark() {
1338 concurrent_mark()->mark_from_roots();
1339 }
1340
1341 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1342 private:
1343 ShenandoahMarkingContext* const _ctx;
1344 public:
1345 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1346
1347 void heap_region_do(ShenandoahHeapRegion* r) {
1348 if (r->is_active()) {
1349 HeapWord *tams = _ctx->top_at_mark_start(r);
1350 HeapWord *top = r->top();
1351 if (top > tams) {
1352 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1353 }
1354 } else {
1355 assert(!r->has_live(),
1356 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number()));
1357 assert(_ctx->top_at_mark_start(r) == r->top(),
1358 err_msg("Region " SIZE_FORMAT " should have correct TAMS", r->region_number()));
1359 }
1360 }
1361
1362 bool is_thread_safe() { return true; }
1363 };
1364
1365 void ShenandoahHeap::op_final_mark() {
1366 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1367
1368 // It is critical that we
1369 // evacuate roots right after finishing marking, so that we don't
1370 // get unmarked objects in the roots.
1371
1372 if (!cancelled_gc()) {
1373 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1374
1375 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->reset_taskqueue_stats());
1376
1377 if (has_forwarded_objects()) {
1378 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1379 }
1380
1381 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->print_taskqueue_stats());
1382
1383 stop_concurrent_marking();
1384
1385 {
1386 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1387
1388 // All allocations past TAMS are implicitly live, adjust the region data.
1389 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1390 ShenandoahCompleteLivenessClosure cl;
1391 parallel_heap_region_iterate(&cl);
1392 }
1393
1394 {
1395 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1396
1397 make_parsable(true);
1398
1399 trash_cset_regions();
1400
1401 {
1402 ShenandoahHeapLocker locker(lock());
1403 _collection_set->clear();
1404 _free_set->clear();
1405
1406 heuristics()->choose_collection_set(_collection_set);
1407 _free_set->rebuild();
1408 }
1409 }
1410
1411 // If collection set has candidates, start evacuation.
1412 // Otherwise, bypass the rest of the cycle.
1413 if (!collection_set()->is_empty()) {
1414 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1415
1416 if (ShenandoahVerify) {
1417 verifier()->verify_before_evacuation();
1418 }
1419
1420 set_evacuation_in_progress(true);
1421 // From here on, we need to update references.
1422 set_has_forwarded_objects(true);
1423
1424 evacuate_and_update_roots();
1425
1426 if (ShenandoahPacing) {
1427 pacer()->setup_for_evac();
1428 }
1429 } else {
1430 if (ShenandoahVerify) {
1431 verifier()->verify_after_concmark();
1432 }
1433
1434 if (VerifyAfterGC) {
1435 Universe::verify();
1436 }
1437 }
1438
1439 } else {
1440 concurrent_mark()->cancel();
1441 stop_concurrent_marking();
1442
1443 if (process_references()) {
1444 // Abandon reference processing right away: pre-cleaning must have failed.
1445 ReferenceProcessor *rp = ref_processor();
1446 rp->disable_discovery();
1447 rp->abandon_partial_discovery();
1448 rp->verify_no_references_recorded();
1449 }
1450 }
1451 }
1452
1453 void ShenandoahHeap::op_final_evac() {
1454 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1455
1456 set_evacuation_in_progress(false);
1457 if (ShenandoahVerify) {
1458 verifier()->verify_after_evacuation();
1459 }
1460
1461 if (VerifyAfterGC) {
1462 Universe::verify();
1463 }
1464 }
1465
1466 void ShenandoahHeap::op_conc_evac() {
1467 ShenandoahEvacuationTask task(this, _collection_set, true);
1468 workers()->run_task(&task);
1469 }
1470
1471 void ShenandoahHeap::op_stw_evac() {
1472 ShenandoahEvacuationTask task(this, _collection_set, false);
1473 workers()->run_task(&task);
1474 }
1475
1476 void ShenandoahHeap::op_updaterefs() {
1477 update_heap_references(true);
1478 }
1479
1480 void ShenandoahHeap::op_cleanup() {
1481 free_set()->recycle_trash();
1482 }
1483
1484 void ShenandoahHeap::op_reset() {
1485 reset_mark_bitmap();
1486 }
1487
1488 void ShenandoahHeap::op_preclean() {
1489 concurrent_mark()->preclean_weak_refs();
1490 }
1491
1492 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1493 ShenandoahMetricsSnapshot metrics;
1494 metrics.snap_before();
1495
1496 full_gc()->do_it(cause);
1497
1498 metrics.snap_after();
1499 metrics.print();
1500
1501 if (metrics.is_good_progress("Full GC")) {
1502 _progress_last_gc.set();
1503 } else {
1504 // Nothing to do. Tell the allocation path that we have failed to make
1505 // progress, and it can finally fail.
1506 _progress_last_gc.unset();
1507 }
1508 }
1509
1510 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1511 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1512 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1513 // some phase, we have to upgrade the Degenerate GC to Full GC.
1514
1515 clear_cancelled_gc();
1516
1517 ShenandoahMetricsSnapshot metrics;
1518 metrics.snap_before();
1519
1520 switch (point) {
1521 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1522 // but enters it at different points, depending on which concurrent phase had
1523 // degenerated.
1524
1525 case _degenerated_outside_cycle:
1526 // We have degenerated from outside the cycle, which means something is bad with
1527 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1528 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1529 // we can do the most aggressive degen cycle, which includes processing references and
1530 // class unloading, unless those features are explicitly disabled.
1531 //
1532 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1533 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1534 set_process_references(heuristics()->can_process_references());
1535 set_unload_classes(heuristics()->can_unload_classes());
1536
1537 op_reset();
1538
1539 op_init_mark();
1540 if (cancelled_gc()) {
1541 op_degenerated_fail();
1542 return;
1543 }
1544
1545 case _degenerated_mark:
1546 op_final_mark();
1547 if (cancelled_gc()) {
1548 op_degenerated_fail();
1549 return;
1550 }
1551
1552 op_cleanup();
1553
1554 case _degenerated_evac:
1555 // If heuristics thinks we should do the cycle, this flag would be set,
1556 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1557 if (is_evacuation_in_progress()) {
1558
1559 // Degeneration under oom-evac protocol might have left some objects in
1560 // collection set un-evacuated. Restart evacuation from the beginning to
1561 // capture all objects. For all the objects that are already evacuated,
1562 // it would be a simple check, which is supposed to be fast. This is also
1563 // safe to do even without degeneration, as CSet iterator is at beginning
1564 // in preparation for evacuation anyway.
1565 collection_set()->clear_current_index();
1566
1567 op_stw_evac();
1568 if (cancelled_gc()) {
1569 op_degenerated_fail();
1570 return;
1571 }
1572 }
1573
1574 // If heuristics thinks we should do the cycle, this flag would be set,
1575 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1576 if (has_forwarded_objects()) {
1577 op_init_updaterefs();
1578 if (cancelled_gc()) {
1579 op_degenerated_fail();
1580 return;
1581 }
1582 }
1583
1584 case _degenerated_updaterefs:
1585 if (has_forwarded_objects()) {
1586 op_final_updaterefs();
1587 if (cancelled_gc()) {
1588 op_degenerated_fail();
1589 return;
1590 }
1591 }
1592
1593 op_cleanup();
1594 break;
1595
1596 default:
1597 ShouldNotReachHere();
1598 }
1599
1600 if (ShenandoahVerify) {
1601 verifier()->verify_after_degenerated();
1602 }
1603
1604 if (VerifyAfterGC) {
1605 Universe::verify();
1606 }
1607
1608 metrics.snap_after();
1609 metrics.print();
1610
1611 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1612 // because that probably means the heap is overloaded and/or fragmented.
1613 if (!metrics.is_good_progress("Degenerated GC")) {
1614 _progress_last_gc.unset();
1615 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1616 op_degenerated_futile();
1617 } else {
1618 _progress_last_gc.set();
1619 }
1620 }
1621
1622 void ShenandoahHeap::op_degenerated_fail() {
1623 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1624 shenandoah_policy()->record_degenerated_upgrade_to_full();
1625 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1626 }
1627
1628 void ShenandoahHeap::op_degenerated_futile() {
1629 shenandoah_policy()->record_degenerated_upgrade_to_full();
1630 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1631 }
1632
1633 void ShenandoahHeap::stop_concurrent_marking() {
1634 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1635 if (!cancelled_gc()) {
1636 // If we needed to update refs, and concurrent marking has been cancelled,
1637 // we need to finish updating references.
1638 set_has_forwarded_objects(false);
1639 mark_complete_marking_context();
1640 }
1641 set_concurrent_mark_in_progress(false);
1642 }
1643
1644 void ShenandoahHeap::force_satb_flush_all_threads() {
1645 if (!is_concurrent_mark_in_progress()) {
1646 // No need to flush SATBs
1647 return;
1648 }
1649
1650 // Do not block if Threads lock is busy. This avoids the potential deadlock
1651 // when this code is called from the periodic task, and something else is
1652 // expecting the periodic task to complete without blocking. On the off-chance
1653 // Threads lock is busy momentarily, try to acquire several times.
1654 for (int t = 0; t < 10; t++) {
1655 if (Threads_lock->try_lock()) {
1656 JavaThread::set_force_satb_flush_all_threads(true);
1657 Threads_lock->unlock();
1658
1659 // The threads are not "acquiring" their thread-local data, but it does not
1660 // hurt to "release" the updates here anyway.
1661 OrderAccess::fence();
1662 break;
1663 }
1664 os::naked_short_sleep(1);
1665 }
1666 }
1667
1668 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1669 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1670 _gc_state.set_cond(mask, value);
1671 JavaThread::set_gc_state_all_threads(_gc_state.raw_value());
1672 }
1673
1674 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1675 set_gc_state_mask(MARKING, in_progress);
1676 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1677 }
1678
1679 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1680 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1681 set_gc_state_mask(EVACUATION, in_progress);
1682 }
1683
1684 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1685 // Initialize Brooks pointer for the next object
1686 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1687 ShenandoahBrooksPointer::initialize(oop(result));
1688 return result;
1689 }
1690
1691 uint ShenandoahHeap::oop_extra_words() {
1692 return ShenandoahBrooksPointer::word_size();
1693 }
1694
1695 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1696 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1697 }
1698
1699 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1700 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1701 }
1702
1703 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1704 if (oopDesc::is_null(obj)) {
1705 return false;
1706 }
1707 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1708 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
1709 return _mark_context->is_marked(obj);
1710 }
1711
1712 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1713 if (oopDesc::is_null(obj)) {
1714 return false;
1715 }
1716 shenandoah_assert_not_forwarded(NULL, obj);
1717 return _mark_context->is_marked(obj);
1718 }
1719
1720 void ShenandoahHeap::ref_processing_init() {
1721 MemRegion mr = reserved_region();
1722
1723 assert(_max_workers > 0, "Sanity");
1724
1725 _ref_processor =
1726 new ReferenceProcessor(mr, // span
1727 ParallelRefProcEnabled, // MT processing
1728 _max_workers, // Degree of MT processing
1729 true, // MT discovery
1730 _max_workers, // Degree of MT discovery
1731 false, // Reference discovery is not atomic
1732 NULL); // No closure, should be installed before use
1733
1734 shenandoah_assert_rp_isalive_not_installed();
1735 }
1736
1737 void ShenandoahHeap::acquire_pending_refs_lock() {
1738 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::acquirePLL);
1739 }
1740
1741 void ShenandoahHeap::release_pending_refs_lock() {
1742 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
1743 }
1744
1745 GCTracer* ShenandoahHeap::tracer() {
1746 return shenandoah_policy()->tracer();
1747 }
1748
1749 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1750 return _free_set->used();
1751 }
1752
1753 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1754 if (try_cancel_gc()) {
1755 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1756 log_info(gc)("%s", msg.buffer());
1757 Events::log(Thread::current(), "%s", msg.buffer());
1758 }
1759 }
1760
1761 uint ShenandoahHeap::max_workers() {
1762 return _max_workers;
1763 }
1764
1765 void ShenandoahHeap::stop() {
1766 // The shutdown sequence should be able to terminate when GC is running.
1767
1768 // Step 0. Notify policy to disable event recording.
1769 _shenandoah_policy->record_shutdown();
1770
1771 // Step 1. Notify control thread that we are in shutdown.
1772 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1773 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1774 _control_thread->prepare_for_graceful_shutdown();
1775
1776 // Step 2. Notify GC workers that we are cancelling GC.
1777 cancel_gc(GCCause::_shenandoah_stop_vm);
1778
1779 // Step 3. Wait until GC worker exits normally.
1780 _control_thread->stop();
1781
1782 // Step 4. Stop String Dedup thread if it is active
1783 if (ShenandoahStringDedup::is_enabled()) {
1784 ShenandoahStringDedup::stop();
1785 }
1786 }
1787
1788 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1789 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1790
1791 ShenandoahGCPhase root_phase(full_gc ?
1792 ShenandoahPhaseTimings::full_gc_purge :
1793 ShenandoahPhaseTimings::purge);
1794
1795 ShenandoahIsAliveSelector alive;
1796 BoolObjectClosure* is_alive = alive.is_alive_closure();
1797
1798 bool purged_class;
1799
1800 // Unload classes and purge SystemDictionary.
1801 {
1802 ShenandoahGCPhase phase(full_gc ?
1803 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1804 ShenandoahPhaseTimings::purge_class_unload);
1805 purged_class = SystemDictionary::do_unloading(is_alive,
1806 full_gc /* do_cleaning*/ );
1807 }
1808
1809 {
1810 ShenandoahGCPhase phase(full_gc ?
1811 ShenandoahPhaseTimings::full_gc_purge_par :
1812 ShenandoahPhaseTimings::purge_par);
1813 uint active = _workers->active_workers();
1814 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
1815 _workers->run_task(&unlink_task);
1816 }
1817
1818 if (ShenandoahStringDedup::is_enabled()) {
1819 ShenandoahGCPhase phase(full_gc ?
1820 ShenandoahPhaseTimings::full_gc_purge_string_dedup :
1821 ShenandoahPhaseTimings::purge_string_dedup);
1822 ShenandoahStringDedup::parallel_cleanup();
1823 }
1824
1825 {
1826 ShenandoahGCPhase phase(full_gc ?
1827 ShenandoahPhaseTimings::full_gc_purge_cldg :
1828 ShenandoahPhaseTimings::purge_cldg);
1829 ClassLoaderDataGraph::purge();
1830 }
1831 }
1832
1833 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1834 set_gc_state_mask(HAS_FORWARDED, cond);
1835 }
1836
1837 void ShenandoahHeap::set_process_references(bool pr) {
1838 _process_references.set_cond(pr);
1839 }
1840
1841 void ShenandoahHeap::set_unload_classes(bool uc) {
1842 _unload_classes.set_cond(uc);
1843 }
1844
1845 bool ShenandoahHeap::process_references() const {
1846 return _process_references.is_set();
1847 }
1848
1849 bool ShenandoahHeap::unload_classes() const {
1850 return _unload_classes.is_set();
1851 }
1852
1853 address ShenandoahHeap::in_cset_fast_test_addr() {
1854 ShenandoahHeap* heap = ShenandoahHeap::heap();
1855 assert(heap->collection_set() != NULL, "Sanity");
1856 return (address) heap->collection_set()->biased_map_address();
1857 }
1858
1859 address ShenandoahHeap::cancelled_gc_addr() {
1860 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1861 }
1862
1863 address ShenandoahHeap::gc_state_addr() {
1864 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1865 }
1866
1867 size_t ShenandoahHeap::conservative_max_heap_alignment() {
1868 size_t align = ShenandoahMaxRegionSize;
1869 if (UseLargePages) {
1870 align = MAX2(align, os::large_page_size());
1871 }
1872 return align;
1873 }
1874
1875 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1876 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1877 }
1878
1879 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1880 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1881 }
1882
1883 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1884 _degenerated_gc_in_progress.set_cond(in_progress);
1885 }
1886
1887 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1888 _full_gc_in_progress.set_cond(in_progress);
1889 }
1890
1891 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
1892 assert (is_full_gc_in_progress(), "should be");
1893 _full_gc_move_in_progress.set_cond(in_progress);
1894 }
1895
1896 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1897 set_gc_state_mask(UPDATEREFS, in_progress);
1898 }
1899
1900 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1901 ShenandoahCodeRoots::add_nmethod(nm);
1902 }
1903
1904 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
1905 ShenandoahCodeRoots::remove_nmethod(nm);
1906 }
1907
1908 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
1909 o = barrier_set()->write_barrier(o);
1910 ShenandoahHeapLocker locker(lock());
1911 heap_region_containing(o)->make_pinned();
1912 return o;
1913 }
1914
1915 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
1916 o = barrier_set()->read_barrier(o);
1917 ShenandoahHeapLocker locker(lock());
1918 heap_region_containing(o)->make_unpinned();
1919 }
1920
1921 GCTimer* ShenandoahHeap::gc_timer() const {
1922 return _gc_timer;
1923 }
1924
1925 #ifdef ASSERT
1926 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
1927 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
1928
1929 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1930 if (UseDynamicNumberOfGCThreads ||
1931 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
1932 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
1933 } else {
1934 // Use ParallelGCThreads inside safepoints
1935 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
1936 }
1937 } else {
1938 if (UseDynamicNumberOfGCThreads ||
1939 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
1940 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
1941 } else {
1942 // Use ConcGCThreads outside safepoints
1943 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
1944 }
1945 }
1946 }
1947 #endif
1948
1949 ShenandoahVerifier* ShenandoahHeap::verifier() {
1950 guarantee(ShenandoahVerify, "Should be enabled");
1951 assert (_verifier != NULL, "sanity");
1952 return _verifier;
1953 }
1954
1955 ShenandoahUpdateHeapRefsClosure::ShenandoahUpdateHeapRefsClosure() :
1956 _heap(ShenandoahHeap::heap()) {}
1957
1958 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
1959 private:
1960 ShenandoahHeap* _heap;
1961 ShenandoahRegionIterator* _regions;
1962 bool _concurrent;
1963
1964 public:
1965 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
1966 AbstractGangTask("Concurrent Update References Task"),
1967 _heap(ShenandoahHeap::heap()),
1968 _regions(regions),
1969 _concurrent(concurrent) {
1970 }
1971
1972 void work(uint worker_id) {
1973 ShenandoahConcurrentWorkerSession worker_session(worker_id);
1974 ShenandoahUpdateHeapRefsClosure cl;
1975 ShenandoahHeapRegion* r = _regions->next();
1976 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
1977 while (r != NULL) {
1978 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
1979 assert (top_at_start_ur >= r->bottom(), "sanity");
1980 if (r->is_active() && !r->is_cset()) {
1981 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
1982 }
1983 if (ShenandoahPacing) {
1984 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
1985 }
1986 if (_heap->cancelled_gc()) {
1987 return;
1988 }
1989 r = _regions->next();
1990 }
1991 }
1992 };
1993
1994 void ShenandoahHeap::update_heap_references(bool concurrent) {
1995 ShenandoahUpdateHeapRefsTask task(&_update_refs_iterator, concurrent);
1996 workers()->run_task(&task);
1997 }
1998
1999 void ShenandoahHeap::op_init_updaterefs() {
2000 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2001
2002 set_evacuation_in_progress(false);
2003
2004 if (ShenandoahVerify) {
2005 verifier()->verify_before_updaterefs();
2006 }
2007
2008 set_update_refs_in_progress(true);
2009 make_parsable(true);
2010 for (uint i = 0; i < num_regions(); i++) {
2011 ShenandoahHeapRegion* r = get_region(i);
2012 r->set_concurrent_iteration_safe_limit(r->top());
2013 }
2014
2015 // Reset iterator.
2016 _update_refs_iterator.reset();
2017
2018 if (ShenandoahPacing) {
2019 pacer()->setup_for_updaterefs();
2020 }
2021 }
2022
2023 void ShenandoahHeap::op_final_updaterefs() {
2024 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2025
2026 // Check if there is left-over work, and finish it
2027 if (_update_refs_iterator.has_next()) {
2028 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2029
2030 // Finish updating references where we left off.
2031 clear_cancelled_gc();
2032 update_heap_references(false);
2033 }
2034
2035 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2036 // everything. On degenerated paths, cancelled gc would not be set anyway.
2037 if (cancelled_gc()) {
2038 clear_cancelled_gc();
2039 }
2040 assert(!cancelled_gc(), "Should have been done right before");
2041
2042 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2043 ShenandoahPhaseTimings::degen_gc_update_roots:
2044 ShenandoahPhaseTimings::final_update_refs_roots);
2045
2046 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2047
2048 trash_cset_regions();
2049 set_has_forwarded_objects(false);
2050 set_update_refs_in_progress(false);
2051
2052 if (ShenandoahVerify) {
2053 verifier()->verify_after_updaterefs();
2054 }
2055
2056 if (VerifyAfterGC) {
2057 Universe::verify();
2058 }
2059
2060 {
2061 ShenandoahHeapLocker locker(lock());
2062 _free_set->rebuild();
2063 }
2064 }
2065
2066 #ifdef ASSERT
2067 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2068 _lock.assert_not_owned_by_current_thread();
2069 }
2070
2071 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2072 _lock.assert_owned_by_current_thread();
2073 }
2074
2075 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2076 _lock.assert_owned_by_current_thread_or_safepoint();
2077 }
2078 #endif
2079
2080 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2081 print_on(st);
2082 print_heap_regions_on(st);
2083 }
2084
2085 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2086 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2087
2088 size_t regions_from = _bitmap_regions_per_slice * slice;
2089 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2090 for (size_t g = regions_from; g < regions_to; g++) {
2091 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2092 if (skip_self && g == r->region_number()) continue;
2093 if (get_region(g)->is_committed()) {
2094 return true;
2095 }
2096 }
2097 return false;
2098 }
2099
2100 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2101 assert_heaplock_owned_by_current_thread();
2102
2103 if (is_bitmap_slice_committed(r, true)) {
2104 // Some other region from the group is already committed, meaning the bitmap
2105 // slice is already committed, we exit right away.
2106 return true;
2107 }
2108
2109 // Commit the bitmap slice:
2110 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2111 size_t off = _bitmap_bytes_per_slice * slice;
2112 size_t len = _bitmap_bytes_per_slice;
2113 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2114 return false;
2115 }
2116 return true;
2117 }
2118
2119 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2120 assert_heaplock_owned_by_current_thread();
2121
2122 if (is_bitmap_slice_committed(r, true)) {
2123 // Some other region from the group is still committed, meaning the bitmap
2124 // slice is should stay committed, exit right away.
2125 return true;
2126 }
2127
2128 // Uncommit the bitmap slice:
2129 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2130 size_t off = _bitmap_bytes_per_slice * slice;
2131 size_t len = _bitmap_bytes_per_slice;
2132 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2133 return false;
2134 }
2135 return true;
2136 }
2137
2138 void ShenandoahHeap::vmop_entry_init_mark() {
2139 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2140 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2141 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2142
2143 try_inject_alloc_failure();
2144 VM_ShenandoahInitMark op;
2145 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2146 }
2147
2148 void ShenandoahHeap::vmop_entry_final_mark() {
2149 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2150 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2151 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2152
2153 try_inject_alloc_failure();
2154 VM_ShenandoahFinalMarkStartEvac op;
2155 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2156 }
2157
2158 void ShenandoahHeap::vmop_entry_final_evac() {
2159 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2160 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2161 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2162
2163 VM_ShenandoahFinalEvac op;
2164 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2165 }
2166
2167 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2168 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2169 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2170 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2171
2172 try_inject_alloc_failure();
2173 VM_ShenandoahInitUpdateRefs op;
2174 VMThread::execute(&op);
2175 }
2176
2177 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2178 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2179 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2180 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2181
2182 try_inject_alloc_failure();
2183 VM_ShenandoahFinalUpdateRefs op;
2184 VMThread::execute(&op);
2185 }
2186
2187 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2188 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2189 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2190 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2191
2192 try_inject_alloc_failure();
2193 VM_ShenandoahFullGC op(cause);
2194 VMThread::execute(&op);
2195 }
2196
2197 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2198 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2199 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2200 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2201
2202 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2203 VMThread::execute(°enerated_gc);
2204 }
2205
2206 void ShenandoahHeap::entry_init_mark() {
2207 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2208 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2209
2210 const char* msg = init_mark_event_message();
2211 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2212 EventMark em("%s", msg);
2213
2214 ShenandoahWorkerScope scope(workers(),
2215 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2216 "init marking");
2217
2218 op_init_mark();
2219 }
2220
2221 void ShenandoahHeap::entry_final_mark() {
2222 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2223 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2224
2225 const char* msg = final_mark_event_message();
2226 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2227 EventMark em("%s", msg);
2228
2229 ShenandoahWorkerScope scope(workers(),
2230 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2231 "final marking");
2232
2233 op_final_mark();
2234 }
2235
2236 void ShenandoahHeap::entry_final_evac() {
2237 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2238 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2239
2240 const char* msg = "Pause Final Evac";
2241 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2242 EventMark em("%s", msg);
2243
2244 op_final_evac();
2245 }
2246
2247 void ShenandoahHeap::entry_init_updaterefs() {
2248 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2249 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2250
2251 static const char* msg = "Pause Init Update Refs";
2252 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2253 EventMark em("%s", msg);
2254
2255 // No workers used in this phase, no setup required
2256
2257 op_init_updaterefs();
2258 }
2259
2260 void ShenandoahHeap::entry_final_updaterefs() {
2261 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2262 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2263
2264 static const char* msg = "Pause Final Update Refs";
2265 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2266 EventMark em("%s", msg);
2267
2268 ShenandoahWorkerScope scope(workers(),
2269 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2270 "final reference update");
2271
2272 op_final_updaterefs();
2273 }
2274
2275 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2276 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2277 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2278
2279 static const char* msg = "Pause Full";
2280 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true);
2281 EventMark em("%s", msg);
2282
2283 ShenandoahWorkerScope scope(workers(),
2284 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2285 "full gc");
2286
2287 op_full(cause);
2288 }
2289
2290 void ShenandoahHeap::entry_degenerated(int point) {
2291 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2292 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2293
2294 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2295 const char* msg = degen_event_message(dpoint);
2296 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true);
2297 EventMark em("%s", msg);
2298
2299 ShenandoahWorkerScope scope(workers(),
2300 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2301 "stw degenerated gc");
2302
2303 set_degenerated_gc_in_progress(true);
2304 op_degenerated(dpoint);
2305 set_degenerated_gc_in_progress(false);
2306 }
2307
2308 void ShenandoahHeap::entry_mark() {
2309 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2310
2311 const char* msg = conc_mark_event_message();
2312 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2313 EventMark em("%s", msg);
2314
2315 ShenandoahWorkerScope scope(workers(),
2316 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2317 "concurrent marking");
2318
2319 try_inject_alloc_failure();
2320 op_mark();
2321 }
2322
2323 void ShenandoahHeap::entry_evac() {
2324 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2325 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2326
2327 static const char *msg = "Concurrent evacuation";
2328 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2329 EventMark em("%s", msg);
2330
2331 ShenandoahWorkerScope scope(workers(),
2332 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2333 "concurrent evacuation");
2334
2335 try_inject_alloc_failure();
2336 op_conc_evac();
2337 }
2338
2339 void ShenandoahHeap::entry_updaterefs() {
2340 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2341
2342 static const char* msg = "Concurrent update references";
2343 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2344 EventMark em("%s", msg);
2345
2346 ShenandoahWorkerScope scope(workers(),
2347 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2348 "concurrent reference update");
2349
2350 try_inject_alloc_failure();
2351 op_updaterefs();
2352 }
2353
2354 void ShenandoahHeap::entry_cleanup() {
2355 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2356
2357 static const char* msg = "Concurrent cleanup";
2358 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2359 EventMark em("%s", msg);
2360
2361 // This phase does not use workers, no need for setup
2362
2363 try_inject_alloc_failure();
2364 op_cleanup();
2365 }
2366
2367 void ShenandoahHeap::entry_reset() {
2368 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2369
2370 static const char* msg = "Concurrent reset";
2371 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2372 EventMark em("%s", msg);
2373
2374 ShenandoahWorkerScope scope(workers(),
2375 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2376 "concurrent reset");
2377
2378 try_inject_alloc_failure();
2379 op_reset();
2380 }
2381
2382 void ShenandoahHeap::entry_preclean() {
2383 if (ShenandoahPreclean && process_references()) {
2384 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2385
2386 static const char* msg = "Concurrent precleaning";
2387 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2388 EventMark em("%s", msg);
2389
2390 ShenandoahWorkerScope scope(workers(),
2391 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2392 "concurrent preclean",
2393 /* check_workers = */ false);
2394
2395 try_inject_alloc_failure();
2396 op_preclean();
2397 }
2398 }
2399
2400 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2401 static const char *msg = "Concurrent uncommit";
2402 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2403 EventMark em("%s", msg);
2404
2405 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2406
2407 op_uncommit(shrink_before);
2408 }
2409
2410 void ShenandoahHeap::try_inject_alloc_failure() {
2411 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2412 _inject_alloc_failure.set();
2413 os::naked_short_sleep(1);
2414 if (cancelled_gc()) {
2415 log_info(gc)("Allocation failure was successfully injected");
2416 }
2417 }
2418 }
2419
2420 bool ShenandoahHeap::should_inject_alloc_failure() {
2421 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2422 }
2423
2424 void ShenandoahHeap::enter_evacuation() {
2425 _oom_evac_handler.enter_evacuation();
2426 }
2427
2428 void ShenandoahHeap::leave_evacuation() {
2429 _oom_evac_handler.leave_evacuation();
2430 }
2431
2432 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2433 _heap(ShenandoahHeap::heap()),
2434 _index(0) {}
2435
2436 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2437 _heap(heap),
2438 _index(0) {}
2439
2440 void ShenandoahRegionIterator::reset() {
2441 _index = 0;
2442 }
2443
2444 bool ShenandoahRegionIterator::has_next() const {
2445 return _index < (jint)_heap->num_regions();
2446 }
2447
2448 char ShenandoahHeap::gc_state() {
2449 return _gc_state.raw_value();
2450 }
2451
2452 const char* ShenandoahHeap::init_mark_event_message() const {
2453 bool update_refs = has_forwarded_objects();
2454 bool proc_refs = process_references();
2455 bool unload_cls = unload_classes();
2456
2457 if (update_refs && proc_refs && unload_cls) {
2458 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2459 } else if (update_refs && proc_refs) {
2460 return "Pause Init Mark (update refs) (process weakrefs)";
2461 } else if (update_refs && unload_cls) {
2462 return "Pause Init Mark (update refs) (unload classes)";
2463 } else if (proc_refs && unload_cls) {
2464 return "Pause Init Mark (process weakrefs) (unload classes)";
2465 } else if (update_refs) {
2466 return "Pause Init Mark (update refs)";
2467 } else if (proc_refs) {
2468 return "Pause Init Mark (process weakrefs)";
2469 } else if (unload_cls) {
2470 return "Pause Init Mark (unload classes)";
2471 } else {
2472 return "Pause Init Mark";
2473 }
2474 }
2475
2476 const char* ShenandoahHeap::final_mark_event_message() const {
2477 bool update_refs = has_forwarded_objects();
2478 bool proc_refs = process_references();
2479 bool unload_cls = unload_classes();
2480
2481 if (update_refs && proc_refs && unload_cls) {
2482 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2483 } else if (update_refs && proc_refs) {
2484 return "Pause Final Mark (update refs) (process weakrefs)";
2485 } else if (update_refs && unload_cls) {
2486 return "Pause Final Mark (update refs) (unload classes)";
2487 } else if (proc_refs && unload_cls) {
2488 return "Pause Final Mark (process weakrefs) (unload classes)";
2489 } else if (update_refs) {
2490 return "Pause Final Mark (update refs)";
2491 } else if (proc_refs) {
2492 return "Pause Final Mark (process weakrefs)";
2493 } else if (unload_cls) {
2494 return "Pause Final Mark (unload classes)";
2495 } else {
2496 return "Pause Final Mark";
2497 }
2498 }
2499
2500 const char* ShenandoahHeap::conc_mark_event_message() const {
2501 bool update_refs = has_forwarded_objects();
2502 bool proc_refs = process_references();
2503 bool unload_cls = unload_classes();
2504
2505 if (update_refs && proc_refs && unload_cls) {
2506 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2507 } else if (update_refs && proc_refs) {
2508 return "Concurrent marking (update refs) (process weakrefs)";
2509 } else if (update_refs && unload_cls) {
2510 return "Concurrent marking (update refs) (unload classes)";
2511 } else if (proc_refs && unload_cls) {
2512 return "Concurrent marking (process weakrefs) (unload classes)";
2513 } else if (update_refs) {
2514 return "Concurrent marking (update refs)";
2515 } else if (proc_refs) {
2516 return "Concurrent marking (process weakrefs)";
2517 } else if (unload_cls) {
2518 return "Concurrent marking (unload classes)";
2519 } else {
2520 return "Concurrent marking";
2521 }
2522 }
2523
2524 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2525 switch (point) {
2526 case _degenerated_unset:
2527 return "Pause Degenerated GC (<UNSET>)";
2528 case _degenerated_outside_cycle:
2529 return "Pause Degenerated GC (Outside of Cycle)";
2530 case _degenerated_mark:
2531 return "Pause Degenerated GC (Mark)";
2532 case _degenerated_evac:
2533 return "Pause Degenerated GC (Evacuation)";
2534 case _degenerated_updaterefs:
2535 return "Pause Degenerated GC (Update Refs)";
2536 default:
2537 ShouldNotReachHere();
2538 return "ERROR";
2539 }
2540 }
2541
2542 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2543 #ifdef ASSERT
2544 assert(worker_id < _max_workers, "sanity");
2545 for (uint i = 0; i < num_regions(); i++) {
2546 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2547 }
2548 #endif
2549 return _liveness_cache[worker_id];
2550 }
2551
2552 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2553 assert(worker_id < _max_workers, "sanity");
2554 jushort* ld = _liveness_cache[worker_id];
2555 for (uint i = 0; i < num_regions(); i++) {
2556 ShenandoahHeapRegion* r = get_region(i);
2557 jushort live = ld[i];
2558 if (live > 0) {
2559 r->increase_live_data_gc_words(live);
2560 ld[i] = 0;
2561 }
2562 }
2563 }
2564
2565 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2566 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2567 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2568 }