1 /*
2 * Copyright (c) 2013, 2019, 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/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/memAllocator.hpp"
30 #include "gc/shared/parallelCleaning.hpp"
31 #include "gc/shared/plab.hpp"
32
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahBrooksPointer.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
37 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
47 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
48 #include "gc/shenandoah/shenandoahMetrics.hpp"
49 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
50 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
51 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
52 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
53 #include "gc/shenandoah/shenandoahStringDedup.hpp"
54 #include "gc/shenandoah/shenandoahUtils.hpp"
55 #include "gc/shenandoah/shenandoahVerifier.hpp"
56 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
57 #include "gc/shenandoah/shenandoahVMOperations.hpp"
58 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
59 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
66
67 #include "memory/metaspace.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/safepointMechanism.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/mallocTracker.hpp"
72
73 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
74
75 #ifdef ASSERT
76 template <class T>
77 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
78 T o = RawAccess<>::oop_load(p);
79 if (! CompressedOops::is_null(o)) {
80 oop obj = CompressedOops::decode_not_null(o);
81 shenandoah_assert_not_forwarded(p, obj);
82 }
83 }
84
85 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
86 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
87 #endif
88
89 class ShenandoahPretouchTask : public AbstractGangTask {
90 private:
91 ShenandoahRegionIterator _regions;
92 const size_t _bitmap_size;
93 const size_t _page_size;
94 char* _bitmap_base;
95 public:
96 ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
97 AbstractGangTask("Shenandoah PreTouch"),
98 _bitmap_size(bitmap_size),
99 _page_size(page_size),
100 _bitmap_base(bitmap_base) {
101 }
102
103 virtual void work(uint worker_id) {
104 ShenandoahHeapRegion* r = _regions.next();
105 while (r != NULL) {
106 os::pretouch_memory(r->bottom(), r->end(), _page_size);
107
108 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
109 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
110 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
111
112 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
113
114 r = _regions.next();
115 }
116 }
117 };
118
119 jint ShenandoahHeap::initialize() {
120 ShenandoahBrooksPointer::initial_checks();
121
122 initialize_heuristics();
123
124 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
125 size_t max_byte_size = collector_policy()->max_heap_byte_size();
126 size_t heap_alignment = collector_policy()->heap_alignment();
127
128 if (ShenandoahAlwaysPreTouch) {
129 // Enabled pre-touch means the entire heap is committed right away.
130 init_byte_size = max_byte_size;
131 }
132
133 Universe::check_alignment(max_byte_size,
134 ShenandoahHeapRegion::region_size_bytes(),
135 "shenandoah heap");
136 Universe::check_alignment(init_byte_size,
137 ShenandoahHeapRegion::region_size_bytes(),
138 "shenandoah heap");
139
140 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
141 heap_alignment);
142 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
143
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 "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 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
182 SATB_Q_CBL_mon,
183 20 /*G1SATBProcessCompletedThreshold */,
184 60 /* G1SATBBufferEnqueueingThresholdPercent */,
185 Shared_SATB_Q_lock);
186
187 // Reserve space for prev and next bitmap.
188 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
189 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
190 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
191 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
192
193 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
194
195 guarantee(bitmap_bytes_per_region != 0,
196 "Bitmap bytes per region should not be zero");
197 guarantee(is_power_of_2(bitmap_bytes_per_region),
198 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
199
200 if (bitmap_page_size > bitmap_bytes_per_region) {
201 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
202 _bitmap_bytes_per_slice = bitmap_page_size;
203 } else {
204 _bitmap_regions_per_slice = 1;
205 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
206 }
207
208 guarantee(_bitmap_regions_per_slice >= 1,
209 "Should have at least one region per slice: " SIZE_FORMAT,
210 _bitmap_regions_per_slice);
211
212 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
213 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
214 _bitmap_bytes_per_slice, bitmap_page_size);
215
216 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
217 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
218 _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
219
220 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
221 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
222 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
223 os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
224 "couldn't allocate initial bitmap");
225
226 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
227
228 if (ShenandoahVerify) {
229 ReservedSpace verify_bitmap(_bitmap_size, page_size);
230 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
231 "couldn't allocate verification bitmap");
232 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
233 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
234 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
235 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
236 }
237
238 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
239
240 {
241 ShenandoahHeapLocker locker(lock());
242 for (size_t i = 0; i < _num_regions; i++) {
243 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
244 (HeapWord*) pgc_rs.base() + reg_size_words * i,
245 reg_size_words,
246 i,
247 i < num_committed_regions);
248
249 _marking_context->initialize_top_at_mark_start(r);
250 _regions[i] = r;
251 assert(!collection_set()->is_in(i), "New region should not be in collection set");
252 }
253
254 // Initialize to complete
255 _marking_context->mark_complete();
256
257 _free_set->rebuild();
258 }
259
260 if (ShenandoahAlwaysPreTouch) {
261 assert (!AlwaysPreTouch, "Should have been overridden");
262
263 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
264 // before initialize() below zeroes it with initializing thread. For any given region,
265 // we touch the region and the corresponding bitmaps from the same thread.
266 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
267
268 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
269 _num_regions, page_size);
270 ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
271 _workers->run_task(&cl);
272 }
273
274 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
275 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
276 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
277 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
278 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
279
280 _traversal_gc = heuristics()->can_do_traversal_gc() ?
281 new ShenandoahTraversalGC(this, _num_regions) :
282 NULL;
283
284 _monitoring_support = new ShenandoahMonitoringSupport(this);
285
286 _phase_timings = new ShenandoahPhaseTimings();
287
288 if (ShenandoahAllocationTrace) {
289 _alloc_tracker = new ShenandoahAllocTracker();
290 }
291
292 ShenandoahStringDedup::initialize();
293
294 _control_thread = new ShenandoahControlThread();
295
296 ShenandoahCodeRoots::initialize();
297
298 log_info(gc, init)("Safepointing mechanism: %s",
299 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
300 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
301
302 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
303 for (uint worker = 0; worker < _max_workers; worker++) {
304 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
305 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
306 }
307
308 return JNI_OK;
309 }
310
311 void ShenandoahHeap::initialize_heuristics() {
312 if (ShenandoahGCHeuristics != NULL) {
313 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
314 _heuristics = new ShenandoahAggressiveHeuristics();
315 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
316 _heuristics = new ShenandoahStaticHeuristics();
317 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
318 _heuristics = new ShenandoahAdaptiveHeuristics();
319 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
320 _heuristics = new ShenandoahPassiveHeuristics();
321 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
322 _heuristics = new ShenandoahCompactHeuristics();
323 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
324 _heuristics = new ShenandoahTraversalHeuristics();
325 } else {
326 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
327 }
328
329 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
330 vm_exit_during_initialization(
331 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
332 _heuristics->name()));
333 }
334 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
335 vm_exit_during_initialization(
336 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
337 _heuristics->name()));
338 }
339
340 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
341 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
342 }
343 log_info(gc, init)("Shenandoah heuristics: %s",
344 _heuristics->name());
345 } else {
346 ShouldNotReachHere();
347 }
348
349 }
350
351 #ifdef _MSC_VER
352 #pragma warning( push )
353 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
354 #endif
355
356 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
357 CollectedHeap(),
358 _initial_size(0),
359 _used(0),
360 _committed(0),
361 _bytes_allocated_since_gc_start(0),
362 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
363 _workers(NULL),
364 _safepoint_workers(NULL),
365 _num_regions(0),
366 _regions(NULL),
367 _update_refs_iterator(this),
368 _control_thread(NULL),
369 _shenandoah_policy(policy),
370 _heuristics(NULL),
371 _free_set(NULL),
372 _scm(new ShenandoahConcurrentMark()),
373 _traversal_gc(NULL),
374 _full_gc(new ShenandoahMarkCompact()),
375 _pacer(NULL),
376 _verifier(NULL),
377 _alloc_tracker(NULL),
378 _phase_timings(NULL),
379 _monitoring_support(NULL),
380 _memory_pool(NULL),
381 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
382 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
383 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
384 _soft_ref_policy(),
385 _ref_processor(NULL),
386 _marking_context(NULL),
387 _collection_set(NULL)
388 {
389 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
390 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
391
392 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
393
394 _max_workers = MAX2(_max_workers, 1U);
395 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
396 /* are_GC_task_threads */true,
397 /* are_ConcurrentGC_threads */false);
398 if (_workers == NULL) {
399 vm_exit_during_initialization("Failed necessary allocation.");
400 } else {
401 _workers->initialize_workers();
402 }
403
404 if (ShenandoahParallelSafepointThreads > 1) {
405 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
406 ShenandoahParallelSafepointThreads,
407 false, false);
408 _safepoint_workers->initialize_workers();
409 }
410 }
411
412 #ifdef _MSC_VER
413 #pragma warning( pop )
414 #endif
415
416 class ShenandoahResetBitmapTask : public AbstractGangTask {
417 private:
418 ShenandoahRegionIterator _regions;
419
420 public:
421 ShenandoahResetBitmapTask() :
422 AbstractGangTask("Parallel Reset Bitmap Task") {}
423
424 void work(uint worker_id) {
425 ShenandoahHeapRegion* region = _regions.next();
426 ShenandoahHeap* heap = ShenandoahHeap::heap();
427 ShenandoahMarkingContext* const ctx = heap->marking_context();
428 while (region != NULL) {
429 if (heap->is_bitmap_slice_committed(region)) {
430 ctx->clear_bitmap(region);
431 }
432 region = _regions.next();
433 }
434 }
435 };
436
437 void ShenandoahHeap::reset_mark_bitmap() {
438 assert_gc_workers(_workers->active_workers());
439 mark_incomplete_marking_context();
440
441 ShenandoahResetBitmapTask task;
442 _workers->run_task(&task);
443 }
444
445 void ShenandoahHeap::print_on(outputStream* st) const {
446 st->print_cr("Shenandoah Heap");
447 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
448 capacity() / K, committed() / K, used() / K);
449 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
450 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
451
452 st->print("Status: ");
453 if (has_forwarded_objects()) st->print("has forwarded objects, ");
454 if (is_concurrent_mark_in_progress()) st->print("marking, ");
455 if (is_evacuation_in_progress()) st->print("evacuating, ");
456 if (is_update_refs_in_progress()) st->print("updating refs, ");
457 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
458 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
459 if (is_full_gc_in_progress()) st->print("full gc, ");
460 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
461
462 if (cancelled_gc()) {
463 st->print("cancelled");
464 } else {
465 st->print("not cancelled");
466 }
467 st->cr();
468
469 st->print_cr("Reserved region:");
470 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
471 p2i(reserved_region().start()),
472 p2i(reserved_region().end()));
473
474 st->cr();
475 MetaspaceUtils::print_on(st);
476
477 if (Verbose) {
478 print_heap_regions_on(st);
479 }
480 }
481
482 class ShenandoahInitGCLABClosure : public ThreadClosure {
483 public:
484 void do_thread(Thread* thread) {
485 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
486 ShenandoahThreadLocalData::initialize_gclab(thread);
487 }
488 }
489 };
490
491 void ShenandoahHeap::post_initialize() {
492 CollectedHeap::post_initialize();
493 MutexLocker ml(Threads_lock);
494
495 ShenandoahInitGCLABClosure init_gclabs;
496 Threads::threads_do(&init_gclabs);
497 _workers->threads_do(&init_gclabs);
498 _safepoint_workers->threads_do(&init_gclabs);
499
500 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
501 // Now, we will let WorkGang to initialize gclab when new worker is created.
502 _workers->set_initialize_gclab();
503
504 _scm->initialize(_max_workers);
505 _full_gc->initialize(_gc_timer);
506
507 ref_processing_init();
508
509 _heuristics->initialize();
510 }
511
512 size_t ShenandoahHeap::used() const {
513 return OrderAccess::load_acquire(&_used);
514 }
515
516 size_t ShenandoahHeap::committed() const {
517 OrderAccess::acquire();
518 return _committed;
519 }
520
521 void ShenandoahHeap::increase_committed(size_t bytes) {
522 assert_heaplock_or_safepoint();
523 _committed += bytes;
524 }
525
526 void ShenandoahHeap::decrease_committed(size_t bytes) {
527 assert_heaplock_or_safepoint();
528 _committed -= bytes;
529 }
530
531 void ShenandoahHeap::increase_used(size_t bytes) {
532 Atomic::add(bytes, &_used);
533 }
534
535 void ShenandoahHeap::set_used(size_t bytes) {
536 OrderAccess::release_store_fence(&_used, bytes);
537 }
538
539 void ShenandoahHeap::decrease_used(size_t bytes) {
540 assert(used() >= bytes, "never decrease heap size by more than we've left");
541 Atomic::sub(bytes, &_used);
542 }
543
544 void ShenandoahHeap::increase_allocated(size_t bytes) {
545 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
546 }
547
548 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
549 size_t bytes = words * HeapWordSize;
550 if (!waste) {
551 increase_used(bytes);
552 }
553 increase_allocated(bytes);
554 if (ShenandoahPacing) {
555 control_thread()->pacing_notify_alloc(words);
556 if (waste) {
557 pacer()->claim_for_alloc(words, true);
558 }
559 }
560 }
561
562 size_t ShenandoahHeap::capacity() const {
563 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
564 }
565
566 size_t ShenandoahHeap::max_capacity() const {
567 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
568 }
569
570 size_t ShenandoahHeap::initial_capacity() const {
571 return _initial_size;
572 }
573
574 bool ShenandoahHeap::is_in(const void* p) const {
575 HeapWord* heap_base = (HeapWord*) base();
576 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
577 return p >= heap_base && p < last_region_end;
578 }
579
580 void ShenandoahHeap::op_uncommit(double shrink_before) {
581 assert (ShenandoahUncommit, "should be enabled");
582
583 size_t count = 0;
584 for (size_t i = 0; i < num_regions(); i++) {
585 ShenandoahHeapRegion* r = get_region(i);
586 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
587 ShenandoahHeapLocker locker(lock());
588 if (r->is_empty_committed()) {
589 r->make_uncommitted();
590 count++;
591 }
592 }
593 SpinPause(); // allow allocators to take the lock
594 }
595
596 if (count > 0) {
597 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
598 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
599 control_thread()->notify_heap_changed();
600 }
601 }
602
603 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
604 // New object should fit the GCLAB size
605 size_t min_size = MAX2(size, PLAB::min_size());
606
607 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
608 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
609 new_size = MIN2(new_size, PLAB::max_size());
610 new_size = MAX2(new_size, PLAB::min_size());
611
612 // Record new heuristic value even if we take any shortcut. This captures
613 // the case when moderately-sized objects always take a shortcut. At some point,
614 // heuristics should catch up with them.
615 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
616
617 if (new_size < size) {
618 // New size still does not fit the object. Fall back to shared allocation.
619 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
620 return NULL;
621 }
622
623 // Retire current GCLAB, and allocate a new one.
624 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
625 gclab->retire();
626
627 size_t actual_size = 0;
628 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
629 if (gclab_buf == NULL) {
630 return NULL;
631 }
632
633 assert (size <= actual_size, "allocation should fit");
634
635 if (ZeroTLAB) {
636 // ..and clear it.
637 Copy::zero_to_words(gclab_buf, actual_size);
638 } else {
639 // ...and zap just allocated object.
640 #ifdef ASSERT
641 // Skip mangling the space corresponding to the object header to
642 // ensure that the returned space is not considered parsable by
643 // any concurrent GC thread.
644 size_t hdr_size = oopDesc::header_size();
645 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
646 #endif // ASSERT
647 }
648 gclab->set_buf(gclab_buf, actual_size);
649 return gclab->allocate(size);
650 }
651
652 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
653 size_t requested_size,
654 size_t* actual_size) {
655 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
656 HeapWord* res = allocate_memory(req);
657 if (res != NULL) {
658 *actual_size = req.actual_size();
659 } else {
660 *actual_size = 0;
661 }
662 return res;
663 }
664
665 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
666 size_t word_size,
667 size_t* actual_size) {
668 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
669 HeapWord* res = allocate_memory(req);
670 if (res != NULL) {
671 *actual_size = req.actual_size();
672 } else {
673 *actual_size = 0;
674 }
675 return res;
676 }
677
678 ShenandoahHeap* ShenandoahHeap::heap() {
679 CollectedHeap* heap = Universe::heap();
680 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
681 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
682 return (ShenandoahHeap*) heap;
683 }
684
685 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
686 CollectedHeap* heap = Universe::heap();
687 return (ShenandoahHeap*) heap;
688 }
689
690 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
691 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
692
693 intptr_t pacer_epoch = 0;
694 bool in_new_region = false;
695 HeapWord* result = NULL;
696
697 if (req.is_mutator_alloc()) {
698 if (ShenandoahPacing) {
699 pacer()->pace_for_alloc(req.size());
700 pacer_epoch = pacer()->epoch();
701 }
702
703 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
704 result = allocate_memory_under_lock(req, in_new_region);
705 }
706
707 // Allocation failed, block until control thread reacted, then retry allocation.
708 //
709 // It might happen that one of the threads requesting allocation would unblock
710 // way later after GC happened, only to fail the second allocation, because
711 // other threads have already depleted the free storage. In this case, a better
712 // strategy is to try again, as long as GC makes progress.
713 //
714 // Then, we need to make sure the allocation was retried after at least one
715 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
716
717 size_t tries = 0;
718
719 while (result == NULL && _progress_last_gc.is_set()) {
720 tries++;
721 control_thread()->handle_alloc_failure(req.size());
722 result = allocate_memory_under_lock(req, in_new_region);
723 }
724
725 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
726 tries++;
727 control_thread()->handle_alloc_failure(req.size());
728 result = allocate_memory_under_lock(req, in_new_region);
729 }
730
731 } else {
732 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
733 result = allocate_memory_under_lock(req, in_new_region);
734 // Do not call handle_alloc_failure() here, because we cannot block.
735 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
736 }
737
738 if (in_new_region) {
739 control_thread()->notify_heap_changed();
740 }
741
742 if (result != NULL) {
743 size_t requested = req.size();
744 size_t actual = req.actual_size();
745
746 assert (req.is_lab_alloc() || (requested == actual),
747 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
748 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
749
750 if (req.is_mutator_alloc()) {
751 notify_mutator_alloc_words(actual, false);
752
753 // If we requested more than we were granted, give the rest back to pacer.
754 // This only matters if we are in the same pacing epoch: do not try to unpace
755 // over the budget for the other phase.
756 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
757 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
758 }
759 } else {
760 increase_used(actual*HeapWordSize);
761 }
762 }
763
764 return result;
765 }
766
767 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
768 ShenandoahHeapLocker locker(lock());
769 return _free_set->allocate(req, in_new_region);
770 }
771
772 class ShenandoahMemAllocator : public MemAllocator {
773 private:
774 MemAllocator& _initializer;
775 public:
776 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
777 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
778 _initializer(initializer) {}
779
780 protected:
781 virtual HeapWord* mem_allocate(Allocation& allocation) const {
782 HeapWord* result = MemAllocator::mem_allocate(allocation);
783 // Initialize brooks-pointer
784 if (result != NULL) {
785 result += ShenandoahBrooksPointer::word_size();
786 ShenandoahBrooksPointer::initialize(oop(result));
787 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
788 }
789 return result;
790 }
791
792 virtual oop initialize(HeapWord* mem) const {
793 return _initializer.initialize(mem);
794 }
795 };
796
797 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
798 ObjAllocator initializer(klass, size, THREAD);
799 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
800 return allocator.allocate();
801 }
802
803 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
804 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
805 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
806 return allocator.allocate();
807 }
808
809 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
810 ClassAllocator initializer(klass, size, THREAD);
811 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
812 return allocator.allocate();
813 }
814
815 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
816 bool* gc_overhead_limit_was_exceeded) {
817 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
818 return allocate_memory(req);
819 }
820
821 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
822 size_t size,
823 Metaspace::MetadataType mdtype) {
824 MetaWord* result;
825
826 // Inform metaspace OOM to GC heuristics if class unloading is possible.
827 if (heuristics()->can_unload_classes()) {
828 ShenandoahHeuristics* h = heuristics();
829 h->record_metaspace_oom();
830 }
831
832 // Expand and retry allocation
833 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
834 if (result != NULL) {
835 return result;
836 }
837
838 // Start full GC
839 collect(GCCause::_metadata_GC_clear_soft_refs);
840
841 // Retry allocation
842 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
843 if (result != NULL) {
844 return result;
845 }
846
847 // Expand and retry allocation
848 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
849 if (result != NULL) {
850 return result;
851 }
852
853 // Out of memory
854 return NULL;
855 }
856
857 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
858 HeapWord* obj = tlab_post_allocation_setup(start);
859 CollectedHeap::fill_with_object(obj, end);
860 }
861
862 size_t ShenandoahHeap::min_dummy_object_size() const {
863 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
864 }
865
866 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
867 private:
868 ShenandoahHeap* _heap;
869 Thread* _thread;
870 public:
871 ShenandoahEvacuateUpdateRootsClosure() :
872 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
873 }
874
875 private:
876 template <class T>
877 void do_oop_work(T* p) {
878 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
879
880 T o = RawAccess<>::oop_load(p);
881 if (! CompressedOops::is_null(o)) {
882 oop obj = CompressedOops::decode_not_null(o);
883 if (_heap->in_collection_set(obj)) {
884 shenandoah_assert_marked(p, obj);
885 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
886 if (oopDesc::equals_raw(resolved, obj)) {
887 resolved = _heap->evacuate_object(obj, _thread);
888 }
889 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
890 }
891 }
892 }
893
894 public:
895 void do_oop(oop* p) {
896 do_oop_work(p);
897 }
898 void do_oop(narrowOop* p) {
899 do_oop_work(p);
900 }
901 };
902
903 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
904 private:
905 ShenandoahHeap* const _heap;
906 Thread* const _thread;
907 public:
908 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
909 _heap(heap), _thread(Thread::current()) {}
910
911 void do_object(oop p) {
912 shenandoah_assert_marked(NULL, p);
913 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
914 _heap->evacuate_object(p, _thread);
915 }
916 }
917 };
918
919 class ShenandoahEvacuationTask : public AbstractGangTask {
920 private:
921 ShenandoahHeap* const _sh;
922 ShenandoahCollectionSet* const _cs;
923 bool _concurrent;
924 public:
925 ShenandoahEvacuationTask(ShenandoahHeap* sh,
926 ShenandoahCollectionSet* cs,
927 bool concurrent) :
928 AbstractGangTask("Parallel Evacuation Task"),
929 _sh(sh),
930 _cs(cs),
931 _concurrent(concurrent)
932 {}
933
934 void work(uint worker_id) {
935 if (_concurrent) {
936 ShenandoahConcurrentWorkerSession worker_session(worker_id);
937 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
938 ShenandoahEvacOOMScope oom_evac_scope;
939 do_work();
940 } else {
941 ShenandoahParallelWorkerSession worker_session(worker_id);
942 ShenandoahEvacOOMScope oom_evac_scope;
943 do_work();
944 }
945 }
946
947 private:
948 void do_work() {
949 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
950 ShenandoahHeapRegion* r;
951 while ((r =_cs->claim_next()) != NULL) {
952 assert(r->has_live(), "all-garbage regions are reclaimed early");
953 _sh->marked_object_iterate(r, &cl);
954
955 if (ShenandoahPacing) {
956 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
957 }
958
959 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
960 break;
961 }
962 }
963 }
964 };
965
966 void ShenandoahHeap::trash_cset_regions() {
967 ShenandoahHeapLocker locker(lock());
968
969 ShenandoahCollectionSet* set = collection_set();
970 ShenandoahHeapRegion* r;
971 set->clear_current_index();
972 while ((r = set->next()) != NULL) {
973 r->make_trash();
974 }
975 collection_set()->clear();
976 }
977
978 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
979 st->print_cr("Heap Regions:");
980 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
981 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
982 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
983 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
984
985 for (size_t i = 0; i < num_regions(); i++) {
986 get_region(i)->print_on(st);
987 }
988 }
989
990 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
991 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
992
993 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
994 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
995 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
996 size_t index = start->region_number() + required_regions - 1;
997
998 assert(!start->has_live(), "liveness must be zero");
999
1000 for(size_t i = 0; i < required_regions; i++) {
1001 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1002 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1003 ShenandoahHeapRegion* region = get_region(index --);
1004
1005 assert(region->is_humongous(), "expect correct humongous start or continuation");
1006 assert(!region->is_cset(), "Humongous region should not be in collection set");
1007
1008 region->make_trash_immediate();
1009 }
1010 }
1011
1012 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1013 public:
1014 void do_thread(Thread* thread) {
1015 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1016 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1017 gclab->retire();
1018 }
1019 };
1020
1021 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1022 if (UseTLAB) {
1023 CollectedHeap::ensure_parsability(retire_tlabs);
1024 }
1025 ShenandoahRetireGCLABClosure cl;
1026 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1027 cl.do_thread(t);
1028 }
1029 workers()->threads_do(&cl);
1030 _safepoint_workers->threads_do(&cl);
1031 }
1032
1033 void ShenandoahHeap::resize_tlabs() {
1034 CollectedHeap::resize_all_tlabs();
1035 }
1036
1037 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1038 private:
1039 ShenandoahRootEvacuator* _rp;
1040
1041 public:
1042 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1043 AbstractGangTask("Shenandoah evacuate and update roots"),
1044 _rp(rp) {}
1045
1046 void work(uint worker_id) {
1047 ShenandoahParallelWorkerSession worker_session(worker_id);
1048 ShenandoahEvacOOMScope oom_evac_scope;
1049 ShenandoahEvacuateUpdateRootsClosure cl;
1050
1051 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1052 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1053 }
1054 };
1055
1056 void ShenandoahHeap::evacuate_and_update_roots() {
1057 #if defined(COMPILER2) || INCLUDE_JVMCI
1058 DerivedPointerTable::clear();
1059 #endif
1060 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1061
1062 {
1063 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1064 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1065 workers()->run_task(&roots_task);
1066 }
1067
1068 #if defined(COMPILER2) || INCLUDE_JVMCI
1069 DerivedPointerTable::update_pointers();
1070 #endif
1071 }
1072
1073 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1074 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1075
1076 CodeBlobToOopClosure blobsCl(cl, false);
1077 CLDToOopClosure cldCl(cl, ClassLoaderData::_claim_strong);
1078
1079 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1080 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1081 }
1082
1083 // Returns size in bytes
1084 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1085 if (ShenandoahElasticTLAB) {
1086 // With Elastic TLABs, return the max allowed size, and let the allocation path
1087 // figure out the safe size for current allocation.
1088 return ShenandoahHeapRegion::max_tlab_size_bytes();
1089 } else {
1090 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1091 }
1092 }
1093
1094 size_t ShenandoahHeap::max_tlab_size() const {
1095 // Returns size in words
1096 return ShenandoahHeapRegion::max_tlab_size_words();
1097 }
1098
1099 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1100 public:
1101 void do_thread(Thread* thread) {
1102 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1103 gclab->retire();
1104 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1105 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1106 }
1107 }
1108 };
1109
1110 void ShenandoahHeap::retire_and_reset_gclabs() {
1111 ShenandoahRetireAndResetGCLABClosure cl;
1112 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1113 cl.do_thread(t);
1114 }
1115 workers()->threads_do(&cl);
1116 _safepoint_workers->threads_do(&cl);
1117 }
1118
1119 void ShenandoahHeap::collect(GCCause::Cause cause) {
1120 control_thread()->request_gc(cause);
1121 }
1122
1123 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1124 //assert(false, "Shouldn't need to do full collections");
1125 }
1126
1127 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1128 return _shenandoah_policy;
1129 }
1130
1131 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1132 Space* sp = heap_region_containing(addr);
1133 if (sp != NULL) {
1134 return sp->block_start(addr);
1135 }
1136 return NULL;
1137 }
1138
1139 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1140 Space* sp = heap_region_containing(addr);
1141 assert(sp != NULL, "block_size of address outside of heap");
1142 return sp->block_size(addr);
1143 }
1144
1145 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1146 Space* sp = heap_region_containing(addr);
1147 return sp->block_is_obj(addr);
1148 }
1149
1150 jlong ShenandoahHeap::millis_since_last_gc() {
1151 double v = heuristics()->time_since_last_gc() * 1000;
1152 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1153 return (jlong)v;
1154 }
1155
1156 void ShenandoahHeap::prepare_for_verify() {
1157 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1158 make_parsable(false);
1159 }
1160 }
1161
1162 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1163 workers()->print_worker_threads_on(st);
1164 if (ShenandoahStringDedup::is_enabled()) {
1165 ShenandoahStringDedup::print_worker_threads_on(st);
1166 }
1167 }
1168
1169 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1170 workers()->threads_do(tcl);
1171 _safepoint_workers->threads_do(tcl);
1172 if (ShenandoahStringDedup::is_enabled()) {
1173 ShenandoahStringDedup::threads_do(tcl);
1174 }
1175 }
1176
1177 void ShenandoahHeap::print_tracing_info() const {
1178 LogTarget(Info, gc, stats) lt;
1179 if (lt.is_enabled()) {
1180 ResourceMark rm;
1181 LogStream ls(lt);
1182
1183 phase_timings()->print_on(&ls);
1184
1185 ls.cr();
1186 ls.cr();
1187
1188 shenandoah_policy()->print_gc_stats(&ls);
1189
1190 ls.cr();
1191 ls.cr();
1192
1193 if (ShenandoahPacing) {
1194 pacer()->print_on(&ls);
1195 }
1196
1197 ls.cr();
1198 ls.cr();
1199
1200 if (ShenandoahAllocationTrace) {
1201 assert(alloc_tracker() != NULL, "Must be");
1202 alloc_tracker()->print_on(&ls);
1203 } else {
1204 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1205 }
1206 }
1207 }
1208
1209 void ShenandoahHeap::verify(VerifyOption vo) {
1210 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1211 if (ShenandoahVerify) {
1212 verifier()->verify_generic(vo);
1213 } else {
1214 // TODO: Consider allocating verification bitmaps on demand,
1215 // and turn this on unconditionally.
1216 }
1217 }
1218 }
1219 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1220 return _free_set->capacity();
1221 }
1222
1223 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1224 private:
1225 MarkBitMap* _bitmap;
1226 Stack<oop,mtGC>* _oop_stack;
1227
1228 template <class T>
1229 void do_oop_work(T* p) {
1230 T o = RawAccess<>::oop_load(p);
1231 if (!CompressedOops::is_null(o)) {
1232 oop obj = CompressedOops::decode_not_null(o);
1233 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1234 assert(oopDesc::is_oop(obj), "must be a valid oop");
1235 if (!_bitmap->is_marked((HeapWord*) obj)) {
1236 _bitmap->mark((HeapWord*) obj);
1237 _oop_stack->push(obj);
1238 }
1239 }
1240 }
1241 public:
1242 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1243 _bitmap(bitmap), _oop_stack(oop_stack) {}
1244 void do_oop(oop* p) { do_oop_work(p); }
1245 void do_oop(narrowOop* p) { do_oop_work(p); }
1246 };
1247
1248 /*
1249 * This is public API, used in preparation of object_iterate().
1250 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1251 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1252 * control, we call SH::make_tlabs_parsable().
1253 */
1254 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1255 // No-op.
1256 }
1257
1258 /*
1259 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1260 *
1261 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1262 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1263 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1264 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1265 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1266 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1267 * wiped the bitmap in preparation for next marking).
1268 *
1269 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1270 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1271 * is allowed to report dead objects, but is not required to do so.
1272 */
1273 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1274 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1275 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1276 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1277 return;
1278 }
1279
1280 // Reset bitmap
1281 _aux_bit_map.clear();
1282
1283 Stack<oop,mtGC> oop_stack;
1284
1285 // First, we process all GC roots. This populates the work stack with initial objects.
1286 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1287 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1288 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1289 CodeBlobToOopClosure blobs(&oops, false);
1290 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1291
1292 // Work through the oop stack to traverse heap.
1293 while (! oop_stack.is_empty()) {
1294 oop obj = oop_stack.pop();
1295 assert(oopDesc::is_oop(obj), "must be a valid oop");
1296 cl->do_object(obj);
1297 obj->oop_iterate(&oops);
1298 }
1299
1300 assert(oop_stack.is_empty(), "should be empty");
1301
1302 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1303 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1304 }
1305 }
1306
1307 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1308 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1309 object_iterate(cl);
1310 }
1311
1312 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1313 for (size_t i = 0; i < num_regions(); i++) {
1314 ShenandoahHeapRegion* current = get_region(i);
1315 blk->heap_region_do(current);
1316 }
1317 }
1318
1319 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1320 private:
1321 ShenandoahHeap* const _heap;
1322 ShenandoahHeapRegionClosure* const _blk;
1323
1324 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1325 volatile size_t _index;
1326 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1327
1328 public:
1329 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1330 AbstractGangTask("Parallel Region Task"),
1331 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1332
1333 void work(uint worker_id) {
1334 size_t stride = ShenandoahParallelRegionStride;
1335
1336 size_t max = _heap->num_regions();
1337 while (_index < max) {
1338 size_t cur = Atomic::add(stride, &_index) - stride;
1339 size_t start = cur;
1340 size_t end = MIN2(cur + stride, max);
1341 if (start >= max) break;
1342
1343 for (size_t i = cur; i < end; i++) {
1344 ShenandoahHeapRegion* current = _heap->get_region(i);
1345 _blk->heap_region_do(current);
1346 }
1347 }
1348 }
1349 };
1350
1351 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1352 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1353 if (num_regions() > ShenandoahParallelRegionStride) {
1354 ShenandoahParallelHeapRegionTask task(blk);
1355 workers()->run_task(&task);
1356 } else {
1357 heap_region_iterate(blk);
1358 }
1359 }
1360
1361 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1362 private:
1363 ShenandoahMarkingContext* const _ctx;
1364 public:
1365 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1366
1367 void heap_region_do(ShenandoahHeapRegion* r) {
1368 if (r->is_active()) {
1369 r->clear_live_data();
1370 _ctx->capture_top_at_mark_start(r);
1371 } else {
1372 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1373 assert(_ctx->top_at_mark_start(r) == r->top(),
1374 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1375 }
1376 }
1377
1378 bool is_thread_safe() { return true; }
1379 };
1380
1381 void ShenandoahHeap::op_init_mark() {
1382 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1383 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1384
1385 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1386 assert(!marking_context()->is_complete(), "should not be complete");
1387
1388 if (ShenandoahVerify) {
1389 verifier()->verify_before_concmark();
1390 }
1391
1392 if (VerifyBeforeGC) {
1393 Universe::verify();
1394 }
1395
1396 set_concurrent_mark_in_progress(true);
1397 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1398 {
1399 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1400 make_parsable(true);
1401 }
1402
1403 {
1404 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1405 ShenandoahClearLivenessClosure clc;
1406 parallel_heap_region_iterate(&clc);
1407 }
1408
1409 // Make above changes visible to worker threads
1410 OrderAccess::fence();
1411
1412 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1413
1414 if (UseTLAB) {
1415 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1416 resize_tlabs();
1417 }
1418
1419 if (ShenandoahPacing) {
1420 pacer()->setup_for_mark();
1421 }
1422 }
1423
1424 void ShenandoahHeap::op_mark() {
1425 concurrent_mark()->mark_from_roots();
1426 }
1427
1428 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1429 private:
1430 ShenandoahMarkingContext* const _ctx;
1431 public:
1432 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1433
1434 void heap_region_do(ShenandoahHeapRegion* r) {
1435 if (r->is_active()) {
1436 HeapWord *tams = _ctx->top_at_mark_start(r);
1437 HeapWord *top = r->top();
1438 if (top > tams) {
1439 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1440 }
1441 } else {
1442 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1443 assert(_ctx->top_at_mark_start(r) == r->top(),
1444 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1445 }
1446 }
1447
1448 bool is_thread_safe() { return true; }
1449 };
1450
1451 void ShenandoahHeap::op_final_mark() {
1452 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1453
1454 // It is critical that we
1455 // evacuate roots right after finishing marking, so that we don't
1456 // get unmarked objects in the roots.
1457
1458 if (!cancelled_gc()) {
1459 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1460
1461 if (has_forwarded_objects()) {
1462 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1463 }
1464
1465 stop_concurrent_marking();
1466
1467 {
1468 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1469
1470 // All allocations past TAMS are implicitly live, adjust the region data.
1471 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1472 ShenandoahCompleteLivenessClosure cl;
1473 parallel_heap_region_iterate(&cl);
1474 }
1475
1476 {
1477 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1478
1479 make_parsable(true);
1480
1481 trash_cset_regions();
1482
1483 {
1484 ShenandoahHeapLocker locker(lock());
1485 _collection_set->clear();
1486 _free_set->clear();
1487
1488 heuristics()->choose_collection_set(_collection_set);
1489
1490 _free_set->rebuild();
1491 }
1492 }
1493
1494 // If collection set has candidates, start evacuation.
1495 // Otherwise, bypass the rest of the cycle.
1496 if (!collection_set()->is_empty()) {
1497 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1498
1499 if (ShenandoahVerify) {
1500 verifier()->verify_before_evacuation();
1501 }
1502
1503 set_evacuation_in_progress(true);
1504 // From here on, we need to update references.
1505 set_has_forwarded_objects(true);
1506
1507 evacuate_and_update_roots();
1508
1509 if (ShenandoahPacing) {
1510 pacer()->setup_for_evac();
1511 }
1512 } else {
1513 if (ShenandoahVerify) {
1514 verifier()->verify_after_concmark();
1515 }
1516
1517 if (VerifyAfterGC) {
1518 Universe::verify();
1519 }
1520 }
1521
1522 } else {
1523 concurrent_mark()->cancel();
1524 stop_concurrent_marking();
1525
1526 if (process_references()) {
1527 // Abandon reference processing right away: pre-cleaning must have failed.
1528 ReferenceProcessor *rp = ref_processor();
1529 rp->disable_discovery();
1530 rp->abandon_partial_discovery();
1531 rp->verify_no_references_recorded();
1532 }
1533 }
1534 }
1535
1536 void ShenandoahHeap::op_final_evac() {
1537 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1538
1539 set_evacuation_in_progress(false);
1540
1541 retire_and_reset_gclabs();
1542
1543 if (ShenandoahVerify) {
1544 verifier()->verify_after_evacuation();
1545 }
1546
1547 if (VerifyAfterGC) {
1548 Universe::verify();
1549 }
1550 }
1551
1552 void ShenandoahHeap::op_conc_evac() {
1553 ShenandoahEvacuationTask task(this, _collection_set, true);
1554 workers()->run_task(&task);
1555 }
1556
1557 void ShenandoahHeap::op_stw_evac() {
1558 ShenandoahEvacuationTask task(this, _collection_set, false);
1559 workers()->run_task(&task);
1560 }
1561
1562 void ShenandoahHeap::op_updaterefs() {
1563 update_heap_references(true);
1564 }
1565
1566 void ShenandoahHeap::op_cleanup() {
1567 free_set()->recycle_trash();
1568 }
1569
1570 void ShenandoahHeap::op_reset() {
1571 reset_mark_bitmap();
1572 }
1573
1574 void ShenandoahHeap::op_preclean() {
1575 concurrent_mark()->preclean_weak_refs();
1576 }
1577
1578 void ShenandoahHeap::op_init_traversal() {
1579 traversal_gc()->init_traversal_collection();
1580 }
1581
1582 void ShenandoahHeap::op_traversal() {
1583 traversal_gc()->concurrent_traversal_collection();
1584 }
1585
1586 void ShenandoahHeap::op_final_traversal() {
1587 traversal_gc()->final_traversal_collection();
1588 }
1589
1590 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1591 ShenandoahMetricsSnapshot metrics;
1592 metrics.snap_before();
1593
1594 full_gc()->do_it(cause);
1595 if (UseTLAB) {
1596 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1597 resize_all_tlabs();
1598 }
1599
1600 metrics.snap_after();
1601 metrics.print();
1602
1603 if (metrics.is_good_progress("Full GC")) {
1604 _progress_last_gc.set();
1605 } else {
1606 // Nothing to do. Tell the allocation path that we have failed to make
1607 // progress, and it can finally fail.
1608 _progress_last_gc.unset();
1609 }
1610 }
1611
1612 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1613 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1614 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1615 // some phase, we have to upgrade the Degenerate GC to Full GC.
1616
1617 clear_cancelled_gc();
1618
1619 ShenandoahMetricsSnapshot metrics;
1620 metrics.snap_before();
1621
1622 switch (point) {
1623 case _degenerated_traversal:
1624 {
1625 // Drop the collection set. Note: this leaves some already forwarded objects
1626 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1627 // workarounds in ShenandoahTraversalHeuristics.
1628
1629 ShenandoahHeapLocker locker(lock());
1630 collection_set()->clear_current_index();
1631 for (size_t i = 0; i < collection_set()->count(); i++) {
1632 ShenandoahHeapRegion* r = collection_set()->next();
1633 r->make_regular_bypass();
1634 }
1635 collection_set()->clear();
1636 }
1637 op_final_traversal();
1638 op_cleanup();
1639 return;
1640
1641 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1642 // but enters it at different points, depending on which concurrent phase had
1643 // degenerated.
1644
1645 case _degenerated_outside_cycle:
1646 // We have degenerated from outside the cycle, which means something is bad with
1647 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1648 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1649 // we can do the most aggressive degen cycle, which includes processing references and
1650 // class unloading, unless those features are explicitly disabled.
1651 //
1652 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1653 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1654 set_process_references(heuristics()->can_process_references());
1655 set_unload_classes(heuristics()->can_unload_classes());
1656
1657 if (heuristics()->can_do_traversal_gc()) {
1658 // Not possible to degenerate from here, upgrade to Full GC right away.
1659 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1660 op_degenerated_fail();
1661 return;
1662 }
1663
1664 op_reset();
1665
1666 op_init_mark();
1667 if (cancelled_gc()) {
1668 op_degenerated_fail();
1669 return;
1670 }
1671
1672 case _degenerated_mark:
1673 op_final_mark();
1674 if (cancelled_gc()) {
1675 op_degenerated_fail();
1676 return;
1677 }
1678
1679 op_cleanup();
1680
1681 case _degenerated_evac:
1682 // If heuristics thinks we should do the cycle, this flag would be set,
1683 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1684 if (is_evacuation_in_progress()) {
1685
1686 // Degeneration under oom-evac protocol might have left some objects in
1687 // collection set un-evacuated. Restart evacuation from the beginning to
1688 // capture all objects. For all the objects that are already evacuated,
1689 // it would be a simple check, which is supposed to be fast. This is also
1690 // safe to do even without degeneration, as CSet iterator is at beginning
1691 // in preparation for evacuation anyway.
1692 collection_set()->clear_current_index();
1693
1694 op_stw_evac();
1695 if (cancelled_gc()) {
1696 op_degenerated_fail();
1697 return;
1698 }
1699 }
1700
1701 // If heuristics thinks we should do the cycle, this flag would be set,
1702 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1703 if (has_forwarded_objects()) {
1704 op_init_updaterefs();
1705 if (cancelled_gc()) {
1706 op_degenerated_fail();
1707 return;
1708 }
1709 }
1710
1711 case _degenerated_updaterefs:
1712 if (has_forwarded_objects()) {
1713 op_final_updaterefs();
1714 if (cancelled_gc()) {
1715 op_degenerated_fail();
1716 return;
1717 }
1718 }
1719
1720 op_cleanup();
1721 break;
1722
1723 default:
1724 ShouldNotReachHere();
1725 }
1726
1727 if (ShenandoahVerify) {
1728 verifier()->verify_after_degenerated();
1729 }
1730
1731 if (VerifyAfterGC) {
1732 Universe::verify();
1733 }
1734
1735 metrics.snap_after();
1736 metrics.print();
1737
1738 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1739 // because that probably means the heap is overloaded and/or fragmented.
1740 if (!metrics.is_good_progress("Degenerated GC")) {
1741 _progress_last_gc.unset();
1742 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1743 op_degenerated_futile();
1744 } else {
1745 _progress_last_gc.set();
1746 }
1747 }
1748
1749 void ShenandoahHeap::op_degenerated_fail() {
1750 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1751 shenandoah_policy()->record_degenerated_upgrade_to_full();
1752 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1753 }
1754
1755 void ShenandoahHeap::op_degenerated_futile() {
1756 shenandoah_policy()->record_degenerated_upgrade_to_full();
1757 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1758 }
1759
1760 void ShenandoahHeap::stop_concurrent_marking() {
1761 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1762 if (!cancelled_gc()) {
1763 // If we needed to update refs, and concurrent marking has been cancelled,
1764 // we need to finish updating references.
1765 set_has_forwarded_objects(false);
1766 mark_complete_marking_context();
1767 }
1768 set_concurrent_mark_in_progress(false);
1769 }
1770
1771 void ShenandoahHeap::force_satb_flush_all_threads() {
1772 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1773 // No need to flush SATBs
1774 return;
1775 }
1776
1777 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1778 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1779 }
1780 // The threads are not "acquiring" their thread-local data, but it does not
1781 // hurt to "release" the updates here anyway.
1782 OrderAccess::fence();
1783 }
1784
1785 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1786 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1787 ShenandoahThreadLocalData::set_gc_state(t, state);
1788 }
1789 }
1790
1791 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1792 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1793 _gc_state.set_cond(mask, value);
1794 set_gc_state_all_threads(_gc_state.raw_value());
1795 }
1796
1797 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1798 set_gc_state_mask(MARKING, in_progress);
1799 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1800 }
1801
1802 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1803 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1804 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1805 }
1806
1807 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1808 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1809 set_gc_state_mask(EVACUATION, in_progress);
1810 }
1811
1812 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1813 // Initialize Brooks pointer for the next object
1814 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1815 ShenandoahBrooksPointer::initialize(oop(result));
1816 return result;
1817 }
1818
1819 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1820 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1821 }
1822
1823 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1824 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1825 }
1826
1827 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1828 if (CompressedOops::is_null(obj)) {
1829 return false;
1830 }
1831 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1832 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1833 return _mark_context->is_marked(obj);
1834 }
1835
1836 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1837 if (CompressedOops::is_null(obj)) {
1838 return false;
1839 }
1840 shenandoah_assert_not_forwarded(NULL, obj);
1841 return _mark_context->is_marked(obj);
1842 }
1843
1844 void ShenandoahHeap::ref_processing_init() {
1845 assert(_max_workers > 0, "Sanity");
1846
1847 _ref_processor =
1848 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1849 ParallelRefProcEnabled, // MT processing
1850 _max_workers, // Degree of MT processing
1851 true, // MT discovery
1852 _max_workers, // Degree of MT discovery
1853 false, // Reference discovery is not atomic
1854 NULL, // No closure, should be installed before use
1855 true); // Scale worker threads
1856
1857 shenandoah_assert_rp_isalive_not_installed();
1858 }
1859
1860 GCTracer* ShenandoahHeap::tracer() {
1861 return shenandoah_policy()->tracer();
1862 }
1863
1864 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1865 return _free_set->used();
1866 }
1867
1868 bool ShenandoahHeap::try_cancel_gc() {
1869 while (true) {
1870 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1871 if (prev == CANCELLABLE) return true;
1872 else if (prev == CANCELLED) return false;
1873 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1874 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1875 {
1876 // We need to provide a safepoint here, otherwise we might
1877 // spin forever if a SP is pending.
1878 ThreadBlockInVM sp(JavaThread::current());
1879 SpinPause();
1880 }
1881 }
1882 }
1883
1884 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1885 if (try_cancel_gc()) {
1886 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1887 log_info(gc)("%s", msg.buffer());
1888 Events::log(Thread::current(), "%s", msg.buffer());
1889 }
1890 }
1891
1892 uint ShenandoahHeap::max_workers() {
1893 return _max_workers;
1894 }
1895
1896 void ShenandoahHeap::stop() {
1897 // The shutdown sequence should be able to terminate when GC is running.
1898
1899 // Step 0. Notify policy to disable event recording.
1900 _shenandoah_policy->record_shutdown();
1901
1902 // Step 1. Notify control thread that we are in shutdown.
1903 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1904 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1905 control_thread()->prepare_for_graceful_shutdown();
1906
1907 // Step 2. Notify GC workers that we are cancelling GC.
1908 cancel_gc(GCCause::_shenandoah_stop_vm);
1909
1910 // Step 3. Wait until GC worker exits normally.
1911 control_thread()->stop();
1912
1913 // Step 4. Stop String Dedup thread if it is active
1914 if (ShenandoahStringDedup::is_enabled()) {
1915 ShenandoahStringDedup::stop();
1916 }
1917 }
1918
1919 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1920 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1921
1922 ShenandoahGCPhase root_phase(full_gc ?
1923 ShenandoahPhaseTimings::full_gc_purge :
1924 ShenandoahPhaseTimings::purge);
1925
1926 ShenandoahIsAliveSelector alive;
1927 BoolObjectClosure* is_alive = alive.is_alive_closure();
1928
1929 bool purged_class;
1930
1931 // Unload classes and purge SystemDictionary.
1932 {
1933 ShenandoahGCPhase phase(full_gc ?
1934 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1935 ShenandoahPhaseTimings::purge_class_unload);
1936 purged_class = SystemDictionary::do_unloading(gc_timer());
1937 }
1938
1939 {
1940 ShenandoahGCPhase phase(full_gc ?
1941 ShenandoahPhaseTimings::full_gc_purge_par :
1942 ShenandoahPhaseTimings::purge_par);
1943 uint active = _workers->active_workers();
1944 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1945 _workers->run_task(&unlink_task);
1946 }
1947
1948 {
1949 ShenandoahGCPhase phase(full_gc ?
1950 ShenandoahPhaseTimings::full_gc_purge_cldg :
1951 ShenandoahPhaseTimings::purge_cldg);
1952 ClassLoaderDataGraph::purge();
1953 }
1954 }
1955
1956 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1957 set_gc_state_mask(HAS_FORWARDED, cond);
1958 }
1959
1960 void ShenandoahHeap::set_process_references(bool pr) {
1961 _process_references.set_cond(pr);
1962 }
1963
1964 void ShenandoahHeap::set_unload_classes(bool uc) {
1965 _unload_classes.set_cond(uc);
1966 }
1967
1968 bool ShenandoahHeap::process_references() const {
1969 return _process_references.is_set();
1970 }
1971
1972 bool ShenandoahHeap::unload_classes() const {
1973 return _unload_classes.is_set();
1974 }
1975
1976 address ShenandoahHeap::in_cset_fast_test_addr() {
1977 ShenandoahHeap* heap = ShenandoahHeap::heap();
1978 assert(heap->collection_set() != NULL, "Sanity");
1979 return (address) heap->collection_set()->biased_map_address();
1980 }
1981
1982 address ShenandoahHeap::cancelled_gc_addr() {
1983 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1984 }
1985
1986 address ShenandoahHeap::gc_state_addr() {
1987 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1988 }
1989
1990 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1991 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1992 }
1993
1994 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1995 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1996 }
1997
1998 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1999 _degenerated_gc_in_progress.set_cond(in_progress);
2000 }
2001
2002 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2003 _full_gc_in_progress.set_cond(in_progress);
2004 }
2005
2006 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2007 assert (is_full_gc_in_progress(), "should be");
2008 _full_gc_move_in_progress.set_cond(in_progress);
2009 }
2010
2011 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2012 set_gc_state_mask(UPDATEREFS, in_progress);
2013 }
2014
2015 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2016 ShenandoahCodeRoots::add_nmethod(nm);
2017 }
2018
2019 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2020 ShenandoahCodeRoots::remove_nmethod(nm);
2021 }
2022
2023 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2024 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2025 ShenandoahHeapLocker locker(lock());
2026 heap_region_containing(o)->make_pinned();
2027 return o;
2028 }
2029
2030 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2031 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2032 ShenandoahHeapLocker locker(lock());
2033 heap_region_containing(o)->make_unpinned();
2034 }
2035
2036 GCTimer* ShenandoahHeap::gc_timer() const {
2037 return _gc_timer;
2038 }
2039
2040 #ifdef ASSERT
2041 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2042 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2043
2044 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2045 if (UseDynamicNumberOfGCThreads ||
2046 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2047 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2048 } else {
2049 // Use ParallelGCThreads inside safepoints
2050 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2051 }
2052 } else {
2053 if (UseDynamicNumberOfGCThreads ||
2054 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2055 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2056 } else {
2057 // Use ConcGCThreads outside safepoints
2058 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2059 }
2060 }
2061 }
2062 #endif
2063
2064 ShenandoahVerifier* ShenandoahHeap::verifier() {
2065 guarantee(ShenandoahVerify, "Should be enabled");
2066 assert (_verifier != NULL, "sanity");
2067 return _verifier;
2068 }
2069
2070 template<class T>
2071 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2072 private:
2073 T cl;
2074 ShenandoahHeap* _heap;
2075 ShenandoahRegionIterator* _regions;
2076 bool _concurrent;
2077 public:
2078 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2079 AbstractGangTask("Concurrent Update References Task"),
2080 cl(T()),
2081 _heap(ShenandoahHeap::heap()),
2082 _regions(regions),
2083 _concurrent(concurrent) {
2084 }
2085
2086 void work(uint worker_id) {
2087 if (_concurrent) {
2088 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2089 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2090 do_work();
2091 } else {
2092 ShenandoahParallelWorkerSession worker_session(worker_id);
2093 do_work();
2094 }
2095 }
2096
2097 private:
2098 void do_work() {
2099 ShenandoahHeapRegion* r = _regions->next();
2100 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2101 while (r != NULL) {
2102 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2103 assert (top_at_start_ur >= r->bottom(), "sanity");
2104 if (r->is_active() && !r->is_cset()) {
2105 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2106 }
2107 if (ShenandoahPacing) {
2108 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2109 }
2110 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2111 return;
2112 }
2113 r = _regions->next();
2114 }
2115 }
2116 };
2117
2118 void ShenandoahHeap::update_heap_references(bool concurrent) {
2119 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2120 workers()->run_task(&task);
2121 }
2122
2123 void ShenandoahHeap::op_init_updaterefs() {
2124 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2125
2126 set_evacuation_in_progress(false);
2127
2128 retire_and_reset_gclabs();
2129
2130 if (ShenandoahVerify) {
2131 verifier()->verify_before_updaterefs();
2132 }
2133
2134 set_update_refs_in_progress(true);
2135 make_parsable(true);
2136 for (uint i = 0; i < num_regions(); i++) {
2137 ShenandoahHeapRegion* r = get_region(i);
2138 r->set_concurrent_iteration_safe_limit(r->top());
2139 }
2140
2141 // Reset iterator.
2142 _update_refs_iterator.reset();
2143
2144 if (ShenandoahPacing) {
2145 pacer()->setup_for_updaterefs();
2146 }
2147 }
2148
2149 void ShenandoahHeap::op_final_updaterefs() {
2150 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2151
2152 // Check if there is left-over work, and finish it
2153 if (_update_refs_iterator.has_next()) {
2154 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2155
2156 // Finish updating references where we left off.
2157 clear_cancelled_gc();
2158 update_heap_references(false);
2159 }
2160
2161 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2162 // everything. On degenerated paths, cancelled gc would not be set anyway.
2163 if (cancelled_gc()) {
2164 clear_cancelled_gc();
2165 }
2166 assert(!cancelled_gc(), "Should have been done right before");
2167
2168 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2169 ShenandoahPhaseTimings::degen_gc_update_roots:
2170 ShenandoahPhaseTimings::final_update_refs_roots);
2171
2172 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2173
2174 trash_cset_regions();
2175 set_has_forwarded_objects(false);
2176 set_update_refs_in_progress(false);
2177
2178 if (ShenandoahVerify) {
2179 verifier()->verify_after_updaterefs();
2180 }
2181
2182 if (VerifyAfterGC) {
2183 Universe::verify();
2184 }
2185
2186 {
2187 ShenandoahHeapLocker locker(lock());
2188 _free_set->rebuild();
2189 }
2190 }
2191
2192 #ifdef ASSERT
2193 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2194 _lock.assert_owned_by_current_thread();
2195 }
2196
2197 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2198 _lock.assert_not_owned_by_current_thread();
2199 }
2200
2201 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2202 _lock.assert_owned_by_current_thread_or_safepoint();
2203 }
2204 #endif
2205
2206 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2207 print_on(st);
2208 print_heap_regions_on(st);
2209 }
2210
2211 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2212 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2213
2214 size_t regions_from = _bitmap_regions_per_slice * slice;
2215 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2216 for (size_t g = regions_from; g < regions_to; g++) {
2217 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2218 if (skip_self && g == r->region_number()) continue;
2219 if (get_region(g)->is_committed()) {
2220 return true;
2221 }
2222 }
2223 return false;
2224 }
2225
2226 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2227 assert_heaplock_owned_by_current_thread();
2228
2229 if (is_bitmap_slice_committed(r, true)) {
2230 // Some other region from the group is already committed, meaning the bitmap
2231 // slice is already committed, we exit right away.
2232 return true;
2233 }
2234
2235 // Commit the bitmap slice:
2236 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2237 size_t off = _bitmap_bytes_per_slice * slice;
2238 size_t len = _bitmap_bytes_per_slice;
2239 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2240 return false;
2241 }
2242 return true;
2243 }
2244
2245 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2246 assert_heaplock_owned_by_current_thread();
2247
2248 if (is_bitmap_slice_committed(r, true)) {
2249 // Some other region from the group is still committed, meaning the bitmap
2250 // slice is should stay committed, exit right away.
2251 return true;
2252 }
2253
2254 // Uncommit the bitmap slice:
2255 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2256 size_t off = _bitmap_bytes_per_slice * slice;
2257 size_t len = _bitmap_bytes_per_slice;
2258 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2259 return false;
2260 }
2261 return true;
2262 }
2263
2264 void ShenandoahHeap::safepoint_synchronize_begin() {
2265 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2266 SuspendibleThreadSet::synchronize();
2267 }
2268 }
2269
2270 void ShenandoahHeap::safepoint_synchronize_end() {
2271 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2272 SuspendibleThreadSet::desynchronize();
2273 }
2274 }
2275
2276 void ShenandoahHeap::vmop_entry_init_mark() {
2277 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2278 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2279 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2280
2281 try_inject_alloc_failure();
2282 VM_ShenandoahInitMark op;
2283 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2284 }
2285
2286 void ShenandoahHeap::vmop_entry_final_mark() {
2287 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2288 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2289 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2290
2291 try_inject_alloc_failure();
2292 VM_ShenandoahFinalMarkStartEvac op;
2293 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2294 }
2295
2296 void ShenandoahHeap::vmop_entry_final_evac() {
2297 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2298 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2299 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2300
2301 VM_ShenandoahFinalEvac op;
2302 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2303 }
2304
2305 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2306 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2307 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2308 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2309
2310 try_inject_alloc_failure();
2311 VM_ShenandoahInitUpdateRefs op;
2312 VMThread::execute(&op);
2313 }
2314
2315 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2316 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2317 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2318 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2319
2320 try_inject_alloc_failure();
2321 VM_ShenandoahFinalUpdateRefs op;
2322 VMThread::execute(&op);
2323 }
2324
2325 void ShenandoahHeap::vmop_entry_init_traversal() {
2326 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2327 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2328 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2329
2330 try_inject_alloc_failure();
2331 VM_ShenandoahInitTraversalGC op;
2332 VMThread::execute(&op);
2333 }
2334
2335 void ShenandoahHeap::vmop_entry_final_traversal() {
2336 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2337 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2338 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2339
2340 try_inject_alloc_failure();
2341 VM_ShenandoahFinalTraversalGC op;
2342 VMThread::execute(&op);
2343 }
2344
2345 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2346 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2347 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2348 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2349
2350 try_inject_alloc_failure();
2351 VM_ShenandoahFullGC op(cause);
2352 VMThread::execute(&op);
2353 }
2354
2355 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2356 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2357 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2358 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2359
2360 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2361 VMThread::execute(°enerated_gc);
2362 }
2363
2364 void ShenandoahHeap::entry_init_mark() {
2365 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2366 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2367 const char* msg = init_mark_event_message();
2368 GCTraceTime(Info, gc) time(msg, gc_timer());
2369 EventMark em("%s", msg);
2370
2371 ShenandoahWorkerScope scope(workers(),
2372 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2373 "init marking");
2374
2375 op_init_mark();
2376 }
2377
2378 void ShenandoahHeap::entry_final_mark() {
2379 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2380 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2381 const char* msg = final_mark_event_message();
2382 GCTraceTime(Info, gc) time(msg, gc_timer());
2383 EventMark em("%s", msg);
2384
2385 ShenandoahWorkerScope scope(workers(),
2386 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2387 "final marking");
2388
2389 op_final_mark();
2390 }
2391
2392 void ShenandoahHeap::entry_final_evac() {
2393 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2394 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2395 static const char* msg = "Pause Final Evac";
2396 GCTraceTime(Info, gc) time(msg, gc_timer());
2397 EventMark em("%s", msg);
2398
2399 op_final_evac();
2400 }
2401
2402 void ShenandoahHeap::entry_init_updaterefs() {
2403 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2404 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2405
2406 static const char* msg = "Pause Init Update Refs";
2407 GCTraceTime(Info, gc) time(msg, gc_timer());
2408 EventMark em("%s", msg);
2409
2410 // No workers used in this phase, no setup required
2411
2412 op_init_updaterefs();
2413 }
2414
2415 void ShenandoahHeap::entry_final_updaterefs() {
2416 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2417 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2418
2419 static const char* msg = "Pause Final Update Refs";
2420 GCTraceTime(Info, gc) time(msg, gc_timer());
2421 EventMark em("%s", msg);
2422
2423 ShenandoahWorkerScope scope(workers(),
2424 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2425 "final reference update");
2426
2427 op_final_updaterefs();
2428 }
2429
2430 void ShenandoahHeap::entry_init_traversal() {
2431 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2432 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2433
2434 static const char* msg = "Pause Init Traversal";
2435 GCTraceTime(Info, gc) time(msg, gc_timer());
2436 EventMark em("%s", msg);
2437
2438 ShenandoahWorkerScope scope(workers(),
2439 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2440 "init traversal");
2441
2442 op_init_traversal();
2443 }
2444
2445 void ShenandoahHeap::entry_final_traversal() {
2446 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2447 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2448
2449 static const char* msg = "Pause Final Traversal";
2450 GCTraceTime(Info, gc) time(msg, gc_timer());
2451 EventMark em("%s", msg);
2452
2453 ShenandoahWorkerScope scope(workers(),
2454 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2455 "final traversal");
2456
2457 op_final_traversal();
2458 }
2459
2460 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2461 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2462 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2463
2464 static const char* msg = "Pause Full";
2465 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2466 EventMark em("%s", msg);
2467
2468 ShenandoahWorkerScope scope(workers(),
2469 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2470 "full gc");
2471
2472 op_full(cause);
2473 }
2474
2475 void ShenandoahHeap::entry_degenerated(int point) {
2476 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2477 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2478
2479 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2480 const char* msg = degen_event_message(dpoint);
2481 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2482 EventMark em("%s", msg);
2483
2484 ShenandoahWorkerScope scope(workers(),
2485 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2486 "stw degenerated gc");
2487
2488 set_degenerated_gc_in_progress(true);
2489 op_degenerated(dpoint);
2490 set_degenerated_gc_in_progress(false);
2491 }
2492
2493 void ShenandoahHeap::entry_mark() {
2494 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2495
2496 const char* msg = conc_mark_event_message();
2497 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2498 EventMark em("%s", msg);
2499
2500 ShenandoahWorkerScope scope(workers(),
2501 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2502 "concurrent marking");
2503
2504 try_inject_alloc_failure();
2505 op_mark();
2506 }
2507
2508 void ShenandoahHeap::entry_evac() {
2509 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2510 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2511
2512 static const char* msg = "Concurrent evacuation";
2513 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2514 EventMark em("%s", msg);
2515
2516 ShenandoahWorkerScope scope(workers(),
2517 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2518 "concurrent evacuation");
2519
2520 try_inject_alloc_failure();
2521 op_conc_evac();
2522 }
2523
2524 void ShenandoahHeap::entry_updaterefs() {
2525 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2526
2527 static const char* msg = "Concurrent update references";
2528 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2529 EventMark em("%s", msg);
2530
2531 ShenandoahWorkerScope scope(workers(),
2532 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2533 "concurrent reference update");
2534
2535 try_inject_alloc_failure();
2536 op_updaterefs();
2537 }
2538 void ShenandoahHeap::entry_cleanup() {
2539 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2540
2541 static const char* msg = "Concurrent cleanup";
2542 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2543 EventMark em("%s", msg);
2544
2545 // This phase does not use workers, no need for setup
2546
2547 try_inject_alloc_failure();
2548 op_cleanup();
2549 }
2550
2551 void ShenandoahHeap::entry_reset() {
2552 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2553
2554 static const char* msg = "Concurrent reset";
2555 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2556 EventMark em("%s", msg);
2557
2558 ShenandoahWorkerScope scope(workers(),
2559 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2560 "concurrent reset");
2561
2562 try_inject_alloc_failure();
2563 op_reset();
2564 }
2565
2566 void ShenandoahHeap::entry_preclean() {
2567 if (ShenandoahPreclean && process_references()) {
2568 static const char* msg = "Concurrent precleaning";
2569 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2570 EventMark em("%s", msg);
2571
2572 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2573
2574 ShenandoahWorkerScope scope(workers(),
2575 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2576 "concurrent preclean",
2577 /* check_workers = */ false);
2578
2579 try_inject_alloc_failure();
2580 op_preclean();
2581 }
2582 }
2583
2584 void ShenandoahHeap::entry_traversal() {
2585 static const char* msg = "Concurrent traversal";
2586 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2587 EventMark em("%s", msg);
2588
2589 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2590
2591 ShenandoahWorkerScope scope(workers(),
2592 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2593 "concurrent traversal");
2594
2595 try_inject_alloc_failure();
2596 op_traversal();
2597 }
2598
2599 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2600 static const char *msg = "Concurrent uncommit";
2601 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2602 EventMark em("%s", msg);
2603
2604 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2605
2606 op_uncommit(shrink_before);
2607 }
2608
2609 void ShenandoahHeap::try_inject_alloc_failure() {
2610 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2611 _inject_alloc_failure.set();
2612 os::naked_short_sleep(1);
2613 if (cancelled_gc()) {
2614 log_info(gc)("Allocation failure was successfully injected");
2615 }
2616 }
2617 }
2618
2619 bool ShenandoahHeap::should_inject_alloc_failure() {
2620 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2621 }
2622
2623 void ShenandoahHeap::initialize_serviceability() {
2624 _memory_pool = new ShenandoahMemoryPool(this);
2625 _cycle_memory_manager.add_pool(_memory_pool);
2626 _stw_memory_manager.add_pool(_memory_pool);
2627 }
2628
2629 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2630 GrowableArray<GCMemoryManager*> memory_managers(2);
2631 memory_managers.append(&_cycle_memory_manager);
2632 memory_managers.append(&_stw_memory_manager);
2633 return memory_managers;
2634 }
2635
2636 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2637 GrowableArray<MemoryPool*> memory_pools(1);
2638 memory_pools.append(_memory_pool);
2639 return memory_pools;
2640 }
2641
2642 void ShenandoahHeap::enter_evacuation() {
2643 _oom_evac_handler.enter_evacuation();
2644 }
2645
2646 void ShenandoahHeap::leave_evacuation() {
2647 _oom_evac_handler.leave_evacuation();
2648 }
2649
2650 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2651 _heap(ShenandoahHeap::heap()),
2652 _index(0) {}
2653
2654 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2655 _heap(heap),
2656 _index(0) {}
2657
2658 void ShenandoahRegionIterator::reset() {
2659 _index = 0;
2660 }
2661
2662 bool ShenandoahRegionIterator::has_next() const {
2663 return _index < _heap->num_regions();
2664 }
2665
2666 char ShenandoahHeap::gc_state() const {
2667 return _gc_state.raw_value();
2668 }
2669
2670 void ShenandoahHeap::deduplicate_string(oop str) {
2671 assert(java_lang_String::is_instance(str), "invariant");
2672
2673 if (ShenandoahStringDedup::is_enabled()) {
2674 ShenandoahStringDedup::deduplicate(str);
2675 }
2676 }
2677
2678 const char* ShenandoahHeap::init_mark_event_message() const {
2679 bool update_refs = has_forwarded_objects();
2680 bool proc_refs = process_references();
2681 bool unload_cls = unload_classes();
2682
2683 if (update_refs && proc_refs && unload_cls) {
2684 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2685 } else if (update_refs && proc_refs) {
2686 return "Pause Init Mark (update refs) (process weakrefs)";
2687 } else if (update_refs && unload_cls) {
2688 return "Pause Init Mark (update refs) (unload classes)";
2689 } else if (proc_refs && unload_cls) {
2690 return "Pause Init Mark (process weakrefs) (unload classes)";
2691 } else if (update_refs) {
2692 return "Pause Init Mark (update refs)";
2693 } else if (proc_refs) {
2694 return "Pause Init Mark (process weakrefs)";
2695 } else if (unload_cls) {
2696 return "Pause Init Mark (unload classes)";
2697 } else {
2698 return "Pause Init Mark";
2699 }
2700 }
2701
2702 const char* ShenandoahHeap::final_mark_event_message() const {
2703 bool update_refs = has_forwarded_objects();
2704 bool proc_refs = process_references();
2705 bool unload_cls = unload_classes();
2706
2707 if (update_refs && proc_refs && unload_cls) {
2708 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2709 } else if (update_refs && proc_refs) {
2710 return "Pause Final Mark (update refs) (process weakrefs)";
2711 } else if (update_refs && unload_cls) {
2712 return "Pause Final Mark (update refs) (unload classes)";
2713 } else if (proc_refs && unload_cls) {
2714 return "Pause Final Mark (process weakrefs) (unload classes)";
2715 } else if (update_refs) {
2716 return "Pause Final Mark (update refs)";
2717 } else if (proc_refs) {
2718 return "Pause Final Mark (process weakrefs)";
2719 } else if (unload_cls) {
2720 return "Pause Final Mark (unload classes)";
2721 } else {
2722 return "Pause Final Mark";
2723 }
2724 }
2725
2726 const char* ShenandoahHeap::conc_mark_event_message() const {
2727 bool update_refs = has_forwarded_objects();
2728 bool proc_refs = process_references();
2729 bool unload_cls = unload_classes();
2730
2731 if (update_refs && proc_refs && unload_cls) {
2732 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2733 } else if (update_refs && proc_refs) {
2734 return "Concurrent marking (update refs) (process weakrefs)";
2735 } else if (update_refs && unload_cls) {
2736 return "Concurrent marking (update refs) (unload classes)";
2737 } else if (proc_refs && unload_cls) {
2738 return "Concurrent marking (process weakrefs) (unload classes)";
2739 } else if (update_refs) {
2740 return "Concurrent marking (update refs)";
2741 } else if (proc_refs) {
2742 return "Concurrent marking (process weakrefs)";
2743 } else if (unload_cls) {
2744 return "Concurrent marking (unload classes)";
2745 } else {
2746 return "Concurrent marking";
2747 }
2748 }
2749
2750 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2751 switch (point) {
2752 case _degenerated_unset:
2753 return "Pause Degenerated GC (<UNSET>)";
2754 case _degenerated_traversal:
2755 return "Pause Degenerated GC (Traversal)";
2756 case _degenerated_outside_cycle:
2757 return "Pause Degenerated GC (Outside of Cycle)";
2758 case _degenerated_mark:
2759 return "Pause Degenerated GC (Mark)";
2760 case _degenerated_evac:
2761 return "Pause Degenerated GC (Evacuation)";
2762 case _degenerated_updaterefs:
2763 return "Pause Degenerated GC (Update Refs)";
2764 default:
2765 ShouldNotReachHere();
2766 return "ERROR";
2767 }
2768 }
2769
2770 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2771 #ifdef ASSERT
2772 assert(worker_id < _max_workers, "sanity");
2773 for (uint i = 0; i < num_regions(); i++) {
2774 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2775 }
2776 #endif
2777 return _liveness_cache[worker_id];
2778 }
2779
2780 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2781 assert(worker_id < _max_workers, "sanity");
2782 jushort* ld = _liveness_cache[worker_id];
2783 for (uint i = 0; i < num_regions(); i++) {
2784 ShenandoahHeapRegion* r = get_region(i);
2785 jushort live = ld[i];
2786 if (live > 0) {
2787 r->increase_live_data_gc_words(live);
2788 ld[i] = 0;
2789 }
2790 }
2791 }
2792
2793 size_t ShenandoahHeap::obj_size(oop obj) const {
2794 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2795 }
2796
2797 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2798 return ShenandoahBrooksPointer::byte_size();
2799 }
2800
2801 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2802 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2803 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2804 }