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/vmThread.hpp"
69 #include "services/mallocTracker.hpp"
70
71 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
72
73 #ifdef ASSERT
74 template <class T>
75 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
76 T o = RawAccess<>::oop_load(p);
77 if (! CompressedOops::is_null(o)) {
78 oop obj = CompressedOops::decode_not_null(o);
79 shenandoah_assert_not_forwarded(p, obj);
80 }
81 }
82
83 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
84 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
85 #endif
86
87 class ShenandoahPretouchTask : public AbstractGangTask {
88 private:
89 ShenandoahRegionIterator _regions;
90 const size_t _bitmap_size;
91 const size_t _page_size;
92 char* _bitmap_base;
93 public:
94 ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
95 AbstractGangTask("Shenandoah PreTouch"),
96 _bitmap_size(bitmap_size),
97 _page_size(page_size),
98 _bitmap_base(bitmap_base) {
99 }
100
101 virtual void work(uint worker_id) {
102 ShenandoahHeapRegion* r = _regions.next();
103 while (r != NULL) {
104 os::pretouch_memory(r->bottom(), r->end(), _page_size);
105
106 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
107 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
108 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
109
110 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
111
112 r = _regions.next();
113 }
114 }
115 };
116
117 jint ShenandoahHeap::initialize() {
118 ShenandoahBrooksPointer::initial_checks();
119
120 initialize_heuristics();
121
122 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
123 size_t max_byte_size = collector_policy()->max_heap_byte_size();
124 size_t heap_alignment = collector_policy()->heap_alignment();
125
126 if (ShenandoahAlwaysPreTouch) {
127 // Enabled pre-touch means the entire heap is committed right away.
128 init_byte_size = max_byte_size;
129 }
130
131 Universe::check_alignment(max_byte_size,
132 ShenandoahHeapRegion::region_size_bytes(),
133 "shenandoah heap");
134 Universe::check_alignment(init_byte_size,
135 ShenandoahHeapRegion::region_size_bytes(),
136 "shenandoah heap");
137
138 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
139 heap_alignment);
140 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
141
142 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
143
144 _num_regions = ShenandoahHeapRegion::region_count();
145
146 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
147 num_committed_regions = MIN2(num_committed_regions, _num_regions);
148 assert(num_committed_regions <= _num_regions, "sanity");
149
150 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
151 _committed = _initial_size;
152
153 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
154 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
155 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
156 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
157 }
158
159 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
160 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
161
162 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
163 _free_set = new ShenandoahFreeSet(this, _num_regions);
164
165 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
166
167 if (ShenandoahPacing) {
168 _pacer = new ShenandoahPacer(this);
169 _pacer->setup_for_idle();
170 } else {
171 _pacer = NULL;
172 }
173
174 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
175 "misaligned heap: " PTR_FORMAT, p2i(base()));
176
177 // The call below uses stuff (the SATB* things) that are in G1, but probably
178 // belong into a shared location.
179 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
180 SATB_Q_CBL_mon,
181 20 /*G1SATBProcessCompletedThreshold */,
182 60 /* G1SATBBufferEnqueueingThresholdPercent */,
183 Shared_SATB_Q_lock);
184
185 // Reserve space for prev and next bitmap.
186 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
187 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
188 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
189 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
190
191 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
192
193 guarantee(bitmap_bytes_per_region != 0,
194 "Bitmap bytes per region should not be zero");
195 guarantee(is_power_of_2(bitmap_bytes_per_region),
196 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
197
198 if (bitmap_page_size > bitmap_bytes_per_region) {
199 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
200 _bitmap_bytes_per_slice = bitmap_page_size;
201 } else {
202 _bitmap_regions_per_slice = 1;
203 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
204 }
205
206 guarantee(_bitmap_regions_per_slice >= 1,
207 "Should have at least one region per slice: " SIZE_FORMAT,
208 _bitmap_regions_per_slice);
209
210 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
211 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
212 _bitmap_bytes_per_slice, bitmap_page_size);
213
214 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
215 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
216 _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
217
218 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
219 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
220 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
221 os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
222 "couldn't allocate initial bitmap");
223
224 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
225
226 if (ShenandoahVerify) {
227 ReservedSpace verify_bitmap(_bitmap_size, page_size);
228 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
229 "couldn't allocate verification bitmap");
230 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
231 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
232 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
233 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
234 }
235
236 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
237
238 {
239 ShenandoahHeapLocker locker(lock());
240 for (size_t i = 0; i < _num_regions; i++) {
241 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
242 (HeapWord*) pgc_rs.base() + reg_size_words * i,
243 reg_size_words,
244 i,
245 i < num_committed_regions);
246
247 _marking_context->initialize_top_at_mark_start(r);
248 _regions[i] = r;
249 assert(!collection_set()->is_in(i), "New region should not be in collection set");
250 }
251
252 // Initialize to complete
253 _marking_context->mark_complete();
254
255 _free_set->rebuild();
256 }
257
258 if (ShenandoahAlwaysPreTouch) {
259 assert (!AlwaysPreTouch, "Should have been overridden");
260
261 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
262 // before initialize() below zeroes it with initializing thread. For any given region,
263 // we touch the region and the corresponding bitmaps from the same thread.
264 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
265
266 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
267 _num_regions, page_size);
268 ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
269 _workers->run_task(&cl);
270 }
271
272 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
273 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
274 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
275 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
276 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
277
278 _traversal_gc = heuristics()->can_do_traversal_gc() ?
279 new ShenandoahTraversalGC(this, _num_regions) :
280 NULL;
281
282 _monitoring_support = new ShenandoahMonitoringSupport(this);
283
284 _phase_timings = new ShenandoahPhaseTimings();
285
286 if (ShenandoahAllocationTrace) {
287 _alloc_tracker = new ShenandoahAllocTracker();
288 }
289
290 ShenandoahStringDedup::initialize();
291
292 _control_thread = new ShenandoahControlThread();
293
294 ShenandoahCodeRoots::initialize();
295
296 log_info(gc, init)("Safepointing mechanism: %s",
297 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
298 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
299
300 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
301 for (uint worker = 0; worker < _max_workers; worker++) {
302 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
303 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
304 }
305
306 return JNI_OK;
307 }
308
309 void ShenandoahHeap::initialize_heuristics() {
310 if (ShenandoahGCHeuristics != NULL) {
311 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
312 _heuristics = new ShenandoahAggressiveHeuristics();
313 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
314 _heuristics = new ShenandoahStaticHeuristics();
315 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
316 _heuristics = new ShenandoahAdaptiveHeuristics();
317 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
318 _heuristics = new ShenandoahPassiveHeuristics();
319 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
320 _heuristics = new ShenandoahCompactHeuristics();
321 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
322 _heuristics = new ShenandoahTraversalHeuristics();
323 } else {
324 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
325 }
326
327 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
328 vm_exit_during_initialization(
329 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
330 _heuristics->name()));
331 }
332 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
333 vm_exit_during_initialization(
334 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
335 _heuristics->name()));
336 }
337
338 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
339 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
340 }
341 log_info(gc, init)("Shenandoah heuristics: %s",
342 _heuristics->name());
343 } else {
344 ShouldNotReachHere();
345 }
346
347 }
348
349 #ifdef _MSC_VER
350 #pragma warning( push )
351 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
352 #endif
353
354 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
355 CollectedHeap(),
356 _initial_size(0),
357 _used(0),
358 _committed(0),
359 _bytes_allocated_since_gc_start(0),
360 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
361 _workers(NULL),
362 _safepoint_workers(NULL),
363 _num_regions(0),
364 _regions(NULL),
365 _update_refs_iterator(this),
366 _control_thread(NULL),
367 _shenandoah_policy(policy),
368 _heuristics(NULL),
369 _free_set(NULL),
370 _scm(new ShenandoahConcurrentMark()),
371 _traversal_gc(NULL),
372 _full_gc(new ShenandoahMarkCompact()),
373 _pacer(NULL),
374 _verifier(NULL),
375 _alloc_tracker(NULL),
376 _phase_timings(NULL),
377 _monitoring_support(NULL),
378 _memory_pool(NULL),
379 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
380 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
381 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
382 _soft_ref_policy(),
383 _ref_processor(NULL),
384 _marking_context(NULL),
385 _collection_set(NULL)
386 {
387 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
388 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
389
390 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
391
392 _max_workers = MAX2(_max_workers, 1U);
393 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
394 /* are_GC_task_threads */true,
395 /* are_ConcurrentGC_threads */false);
396 if (_workers == NULL) {
397 vm_exit_during_initialization("Failed necessary allocation.");
398 } else {
399 _workers->initialize_workers();
400 }
401
402 if (ShenandoahParallelSafepointThreads > 1) {
403 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
404 ShenandoahParallelSafepointThreads,
405 false, false);
406 _safepoint_workers->initialize_workers();
407 }
408 }
409
410 #ifdef _MSC_VER
411 #pragma warning( pop )
412 #endif
413
414 class ShenandoahResetBitmapTask : public AbstractGangTask {
415 private:
416 ShenandoahRegionIterator _regions;
417
418 public:
419 ShenandoahResetBitmapTask() :
420 AbstractGangTask("Parallel Reset Bitmap Task") {}
421
422 void work(uint worker_id) {
423 ShenandoahHeapRegion* region = _regions.next();
424 ShenandoahHeap* heap = ShenandoahHeap::heap();
425 ShenandoahMarkingContext* const ctx = heap->marking_context();
426 while (region != NULL) {
427 if (heap->is_bitmap_slice_committed(region)) {
428 ctx->clear_bitmap(region);
429 }
430 region = _regions.next();
431 }
432 }
433 };
434
435 void ShenandoahHeap::reset_mark_bitmap() {
436 assert_gc_workers(_workers->active_workers());
437 mark_incomplete_marking_context();
438
439 ShenandoahResetBitmapTask task;
440 _workers->run_task(&task);
441 }
442
443 void ShenandoahHeap::print_on(outputStream* st) const {
444 st->print_cr("Shenandoah Heap");
445 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
446 capacity() / K, committed() / K, used() / K);
447 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
448 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
449
450 st->print("Status: ");
451 if (has_forwarded_objects()) st->print("has forwarded objects, ");
452 if (is_concurrent_mark_in_progress()) st->print("marking, ");
453 if (is_evacuation_in_progress()) st->print("evacuating, ");
454 if (is_update_refs_in_progress()) st->print("updating refs, ");
455 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
456 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
457 if (is_full_gc_in_progress()) st->print("full gc, ");
458 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
459
460 if (cancelled_gc()) {
461 st->print("cancelled");
462 } else {
463 st->print("not cancelled");
464 }
465 st->cr();
466
467 st->print_cr("Reserved region:");
468 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
469 p2i(reserved_region().start()),
470 p2i(reserved_region().end()));
471
472 st->cr();
473 MetaspaceUtils::print_on(st);
474
475 if (Verbose) {
476 print_heap_regions_on(st);
477 }
478 }
479
480 class ShenandoahInitGCLABClosure : public ThreadClosure {
481 public:
482 void do_thread(Thread* thread) {
483 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
484 ShenandoahThreadLocalData::initialize_gclab(thread);
485 }
486 }
487 };
488
489 void ShenandoahHeap::post_initialize() {
490 CollectedHeap::post_initialize();
491 MutexLocker ml(Threads_lock);
492
493 ShenandoahInitGCLABClosure init_gclabs;
494 Threads::threads_do(&init_gclabs);
495 _workers->threads_do(&init_gclabs);
496 _safepoint_workers->threads_do(&init_gclabs);
497
498 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
499 // Now, we will let WorkGang to initialize gclab when new worker is created.
500 _workers->set_initialize_gclab();
501
502 _scm->initialize(_max_workers);
503 _full_gc->initialize(_gc_timer);
504
505 ref_processing_init();
506
507 _heuristics->initialize();
508 }
509
510 size_t ShenandoahHeap::used() const {
511 return OrderAccess::load_acquire(&_used);
512 }
513
514 size_t ShenandoahHeap::committed() const {
515 OrderAccess::acquire();
516 return _committed;
517 }
518
519 void ShenandoahHeap::increase_committed(size_t bytes) {
520 assert_heaplock_or_safepoint();
521 _committed += bytes;
522 }
523
524 void ShenandoahHeap::decrease_committed(size_t bytes) {
525 assert_heaplock_or_safepoint();
526 _committed -= bytes;
527 }
528
529 void ShenandoahHeap::increase_used(size_t bytes) {
530 Atomic::add(bytes, &_used);
531 }
532
533 void ShenandoahHeap::set_used(size_t bytes) {
534 OrderAccess::release_store_fence(&_used, bytes);
535 }
536
537 void ShenandoahHeap::decrease_used(size_t bytes) {
538 assert(used() >= bytes, "never decrease heap size by more than we've left");
539 Atomic::sub(bytes, &_used);
540 }
541
542 void ShenandoahHeap::increase_allocated(size_t bytes) {
543 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
544 }
545
546 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
547 size_t bytes = words * HeapWordSize;
548 if (!waste) {
549 increase_used(bytes);
550 }
551 increase_allocated(bytes);
552 if (ShenandoahPacing) {
553 control_thread()->pacing_notify_alloc(words);
554 if (waste) {
555 pacer()->claim_for_alloc(words, true);
556 }
557 }
558 }
559
560 size_t ShenandoahHeap::capacity() const {
561 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
562 }
563
564 size_t ShenandoahHeap::max_capacity() const {
565 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
566 }
567
568 size_t ShenandoahHeap::initial_capacity() const {
569 return _initial_size;
570 }
571
572 bool ShenandoahHeap::is_in(const void* p) const {
573 HeapWord* heap_base = (HeapWord*) base();
574 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
575 return p >= heap_base && p < last_region_end;
576 }
577
578 void ShenandoahHeap::op_uncommit(double shrink_before) {
579 assert (ShenandoahUncommit, "should be enabled");
580
581 size_t count = 0;
582 for (size_t i = 0; i < num_regions(); i++) {
583 ShenandoahHeapRegion* r = get_region(i);
584 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
585 ShenandoahHeapLocker locker(lock());
586 if (r->is_empty_committed()) {
587 r->make_uncommitted();
588 count++;
589 }
590 }
591 SpinPause(); // allow allocators to take the lock
592 }
593
594 if (count > 0) {
595 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
596 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
597 control_thread()->notify_heap_changed();
598 }
599 }
600
601 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
602 // New object should fit the GCLAB size
603 size_t min_size = MAX2(size, PLAB::min_size());
604
605 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
606 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
607 new_size = MIN2(new_size, PLAB::max_size());
608 new_size = MAX2(new_size, PLAB::min_size());
609
610 // Record new heuristic value even if we take any shortcut. This captures
611 // the case when moderately-sized objects always take a shortcut. At some point,
612 // heuristics should catch up with them.
613 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
614
615 if (new_size < size) {
616 // New size still does not fit the object. Fall back to shared allocation.
617 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
618 return NULL;
619 }
620
621 // Retire current GCLAB, and allocate a new one.
622 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
623 gclab->retire();
624
625 size_t actual_size = 0;
626 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
627 if (gclab_buf == NULL) {
628 return NULL;
629 }
630
631 assert (size <= actual_size, "allocation should fit");
632
633 if (ZeroTLAB) {
634 // ..and clear it.
635 Copy::zero_to_words(gclab_buf, actual_size);
636 } else {
637 // ...and zap just allocated object.
638 #ifdef ASSERT
639 // Skip mangling the space corresponding to the object header to
640 // ensure that the returned space is not considered parsable by
641 // any concurrent GC thread.
642 size_t hdr_size = oopDesc::header_size();
643 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
644 #endif // ASSERT
645 }
646 gclab->set_buf(gclab_buf, actual_size);
647 return gclab->allocate(size);
648 }
649
650 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
651 size_t requested_size,
652 size_t* actual_size) {
653 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
654 HeapWord* res = allocate_memory(req);
655 if (res != NULL) {
656 *actual_size = req.actual_size();
657 } else {
658 *actual_size = 0;
659 }
660 return res;
661 }
662
663 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
664 size_t word_size,
665 size_t* actual_size) {
666 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
667 HeapWord* res = allocate_memory(req);
668 if (res != NULL) {
669 *actual_size = req.actual_size();
670 } else {
671 *actual_size = 0;
672 }
673 return res;
674 }
675
676 ShenandoahHeap* ShenandoahHeap::heap() {
677 CollectedHeap* heap = Universe::heap();
678 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
679 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
680 return (ShenandoahHeap*) heap;
681 }
682
683 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
684 CollectedHeap* heap = Universe::heap();
685 return (ShenandoahHeap*) heap;
686 }
687
688 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
689 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
690
691 intptr_t pacer_epoch = 0;
692 bool in_new_region = false;
693 HeapWord* result = NULL;
694
695 if (req.is_mutator_alloc()) {
696 if (ShenandoahPacing) {
697 pacer()->pace_for_alloc(req.size());
698 pacer_epoch = pacer()->epoch();
699 }
700
701 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
702 result = allocate_memory_under_lock(req, in_new_region);
703 }
704
705 // Allocation failed, block until control thread reacted, then retry allocation.
706 //
707 // It might happen that one of the threads requesting allocation would unblock
708 // way later after GC happened, only to fail the second allocation, because
709 // other threads have already depleted the free storage. In this case, a better
710 // strategy is to try again, as long as GC makes progress.
711 //
712 // Then, we need to make sure the allocation was retried after at least one
713 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
714
715 size_t tries = 0;
716
717 while (result == NULL && _progress_last_gc.is_set()) {
718 tries++;
719 control_thread()->handle_alloc_failure(req.size());
720 result = allocate_memory_under_lock(req, in_new_region);
721 }
722
723 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
724 tries++;
725 control_thread()->handle_alloc_failure(req.size());
726 result = allocate_memory_under_lock(req, in_new_region);
727 }
728
729 } else {
730 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
731 result = allocate_memory_under_lock(req, in_new_region);
732 // Do not call handle_alloc_failure() here, because we cannot block.
733 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
734 }
735
736 if (in_new_region) {
737 control_thread()->notify_heap_changed();
738 }
739
740 if (result != NULL) {
741 size_t requested = req.size();
742 size_t actual = req.actual_size();
743
744 assert (req.is_lab_alloc() || (requested == actual),
745 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
746 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
747
748 if (req.is_mutator_alloc()) {
749 notify_mutator_alloc_words(actual, false);
750
751 // If we requested more than we were granted, give the rest back to pacer.
752 // This only matters if we are in the same pacing epoch: do not try to unpace
753 // over the budget for the other phase.
754 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
755 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
756 }
757 } else {
758 increase_used(actual*HeapWordSize);
759 }
760 }
761
762 return result;
763 }
764
765 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
766 ShenandoahHeapLocker locker(lock());
767 return _free_set->allocate(req, in_new_region);
768 }
769
770 class ShenandoahMemAllocator : public MemAllocator {
771 private:
772 MemAllocator& _initializer;
773 public:
774 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
775 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
776 _initializer(initializer) {}
777
778 protected:
779 virtual HeapWord* mem_allocate(Allocation& allocation) const {
780 HeapWord* result = MemAllocator::mem_allocate(allocation);
781 // Initialize brooks-pointer
782 if (result != NULL) {
783 result += ShenandoahBrooksPointer::word_size();
784 ShenandoahBrooksPointer::initialize(oop(result));
785 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
786 }
787 return result;
788 }
789
790 virtual oop initialize(HeapWord* mem) const {
791 return _initializer.initialize(mem);
792 }
793 };
794
795 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
796 ObjAllocator initializer(klass, size, THREAD);
797 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
798 return allocator.allocate();
799 }
800
801 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
802 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
803 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
804 return allocator.allocate();
805 }
806
807 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
808 ClassAllocator initializer(klass, size, THREAD);
809 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
810 return allocator.allocate();
811 }
812
813 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
814 bool* gc_overhead_limit_was_exceeded) {
815 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
816 return allocate_memory(req);
817 }
818
819 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
820 size_t size,
821 Metaspace::MetadataType mdtype) {
822 MetaWord* result;
823
824 // Inform metaspace OOM to GC heuristics if class unloading is possible.
825 if (heuristics()->can_unload_classes()) {
826 ShenandoahHeuristics* h = heuristics();
827 h->record_metaspace_oom();
828 }
829
830 // Expand and retry allocation
831 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
832 if (result != NULL) {
833 return result;
834 }
835
836 // Start full GC
837 collect(GCCause::_metadata_GC_clear_soft_refs);
838
839 // Retry allocation
840 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
841 if (result != NULL) {
842 return result;
843 }
844
845 // Expand and retry allocation
846 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
847 if (result != NULL) {
848 return result;
849 }
850
851 // Out of memory
852 return NULL;
853 }
854
855 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
856 HeapWord* obj = tlab_post_allocation_setup(start);
857 CollectedHeap::fill_with_object(obj, end);
858 }
859
860 size_t ShenandoahHeap::min_dummy_object_size() const {
861 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
862 }
863
864 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
865 private:
866 ShenandoahHeap* _heap;
867 Thread* _thread;
868 public:
869 ShenandoahEvacuateUpdateRootsClosure() :
870 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
871 }
872
873 private:
874 template <class T>
875 void do_oop_work(T* p) {
876 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
877
878 T o = RawAccess<>::oop_load(p);
879 if (! CompressedOops::is_null(o)) {
880 oop obj = CompressedOops::decode_not_null(o);
881 if (_heap->in_collection_set(obj)) {
882 shenandoah_assert_marked(p, obj);
883 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
884 if (oopDesc::equals_raw(resolved, obj)) {
885 resolved = _heap->evacuate_object(obj, _thread);
886 }
887 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
888 }
889 }
890 }
891
892 public:
893 void do_oop(oop* p) {
894 do_oop_work(p);
895 }
896 void do_oop(narrowOop* p) {
897 do_oop_work(p);
898 }
899 };
900
901 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
902 private:
903 ShenandoahHeap* const _heap;
904 Thread* const _thread;
905 public:
906 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
907 _heap(heap), _thread(Thread::current()) {}
908
909 void do_object(oop p) {
910 shenandoah_assert_marked(NULL, p);
911 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
912 _heap->evacuate_object(p, _thread);
913 }
914 }
915 };
916
917 class ShenandoahEvacuationTask : public AbstractGangTask {
918 private:
919 ShenandoahHeap* const _sh;
920 ShenandoahCollectionSet* const _cs;
921 bool _concurrent;
922 public:
923 ShenandoahEvacuationTask(ShenandoahHeap* sh,
924 ShenandoahCollectionSet* cs,
925 bool concurrent) :
926 AbstractGangTask("Parallel Evacuation Task"),
927 _sh(sh),
928 _cs(cs),
929 _concurrent(concurrent)
930 {}
931
932 void work(uint worker_id) {
933 if (_concurrent) {
934 ShenandoahConcurrentWorkerSession worker_session(worker_id);
935 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
936 ShenandoahEvacOOMScope oom_evac_scope;
937 do_work();
938 } else {
939 ShenandoahParallelWorkerSession worker_session(worker_id);
940 ShenandoahEvacOOMScope oom_evac_scope;
941 do_work();
942 }
943 }
944
945 private:
946 void do_work() {
947 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
948 ShenandoahHeapRegion* r;
949 while ((r =_cs->claim_next()) != NULL) {
950 assert(r->has_live(), "all-garbage regions are reclaimed early");
951 _sh->marked_object_iterate(r, &cl);
952
953 if (ShenandoahPacing) {
954 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
955 }
956
957 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
958 break;
959 }
960 }
961 }
962 };
963
964 void ShenandoahHeap::trash_cset_regions() {
965 ShenandoahHeapLocker locker(lock());
966
967 ShenandoahCollectionSet* set = collection_set();
968 ShenandoahHeapRegion* r;
969 set->clear_current_index();
970 while ((r = set->next()) != NULL) {
971 r->make_trash();
972 }
973 collection_set()->clear();
974 }
975
976 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
977 st->print_cr("Heap Regions:");
978 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
979 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
980 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
981 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
982
983 for (size_t i = 0; i < num_regions(); i++) {
984 get_region(i)->print_on(st);
985 }
986 }
987
988 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
989 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
990
991 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
992 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
993 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
994 size_t index = start->region_number() + required_regions - 1;
995
996 assert(!start->has_live(), "liveness must be zero");
997
998 for(size_t i = 0; i < required_regions; i++) {
999 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1000 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1001 ShenandoahHeapRegion* region = get_region(index --);
1002
1003 assert(region->is_humongous(), "expect correct humongous start or continuation");
1004 assert(!region->is_cset(), "Humongous region should not be in collection set");
1005
1006 region->make_trash_immediate();
1007 }
1008 }
1009
1010 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1011 public:
1012 void do_thread(Thread* thread) {
1013 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1014 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1015 gclab->retire();
1016 }
1017 };
1018
1019 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1020 if (UseTLAB) {
1021 CollectedHeap::ensure_parsability(retire_tlabs);
1022 }
1023 ShenandoahRetireGCLABClosure cl;
1024 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1025 cl.do_thread(t);
1026 }
1027 workers()->threads_do(&cl);
1028 _safepoint_workers->threads_do(&cl);
1029 }
1030
1031 void ShenandoahHeap::resize_tlabs() {
1032 CollectedHeap::resize_all_tlabs();
1033 }
1034
1035 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1036 private:
1037 ShenandoahRootEvacuator* _rp;
1038
1039 public:
1040 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1041 AbstractGangTask("Shenandoah evacuate and update roots"),
1042 _rp(rp) {}
1043
1044 void work(uint worker_id) {
1045 ShenandoahParallelWorkerSession worker_session(worker_id);
1046 ShenandoahEvacOOMScope oom_evac_scope;
1047 ShenandoahEvacuateUpdateRootsClosure cl;
1048
1049 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1050 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1051 }
1052 };
1053
1054 void ShenandoahHeap::evacuate_and_update_roots() {
1055 #if defined(COMPILER2) || INCLUDE_JVMCI
1056 DerivedPointerTable::clear();
1057 #endif
1058 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1059
1060 {
1061 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1062 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1063 workers()->run_task(&roots_task);
1064 }
1065
1066 #if defined(COMPILER2) || INCLUDE_JVMCI
1067 DerivedPointerTable::update_pointers();
1068 #endif
1069 }
1070
1071 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1072 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1073
1074 CodeBlobToOopClosure blobsCl(cl, false);
1075 CLDToOopClosure cldCl(cl, ClassLoaderData::_claim_strong);
1076
1077 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1078 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1079 }
1080
1081 // Returns size in bytes
1082 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1083 if (ShenandoahElasticTLAB) {
1084 // With Elastic TLABs, return the max allowed size, and let the allocation path
1085 // figure out the safe size for current allocation.
1086 return ShenandoahHeapRegion::max_tlab_size_bytes();
1087 } else {
1088 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1089 }
1090 }
1091
1092 size_t ShenandoahHeap::max_tlab_size() const {
1093 // Returns size in words
1094 return ShenandoahHeapRegion::max_tlab_size_words();
1095 }
1096
1097 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1098 public:
1099 void do_thread(Thread* thread) {
1100 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1101 gclab->retire();
1102 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1103 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1104 }
1105 }
1106 };
1107
1108 void ShenandoahHeap::retire_and_reset_gclabs() {
1109 ShenandoahRetireAndResetGCLABClosure cl;
1110 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1111 cl.do_thread(t);
1112 }
1113 workers()->threads_do(&cl);
1114 _safepoint_workers->threads_do(&cl);
1115 }
1116
1117 void ShenandoahHeap::collect(GCCause::Cause cause) {
1118 control_thread()->request_gc(cause);
1119 }
1120
1121 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1122 //assert(false, "Shouldn't need to do full collections");
1123 }
1124
1125 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1126 return _shenandoah_policy;
1127 }
1128
1129 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1130 Space* sp = heap_region_containing(addr);
1131 if (sp != NULL) {
1132 return sp->block_start(addr);
1133 }
1134 return NULL;
1135 }
1136
1137 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1138 Space* sp = heap_region_containing(addr);
1139 assert(sp != NULL, "block_size of address outside of heap");
1140 return sp->block_size(addr);
1141 }
1142
1143 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1144 Space* sp = heap_region_containing(addr);
1145 return sp->block_is_obj(addr);
1146 }
1147
1148 jlong ShenandoahHeap::millis_since_last_gc() {
1149 double v = heuristics()->time_since_last_gc() * 1000;
1150 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1151 return (jlong)v;
1152 }
1153
1154 void ShenandoahHeap::prepare_for_verify() {
1155 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1156 make_parsable(false);
1157 }
1158 }
1159
1160 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1161 workers()->print_worker_threads_on(st);
1162 if (ShenandoahStringDedup::is_enabled()) {
1163 ShenandoahStringDedup::print_worker_threads_on(st);
1164 }
1165 }
1166
1167 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1168 workers()->threads_do(tcl);
1169 _safepoint_workers->threads_do(tcl);
1170 if (ShenandoahStringDedup::is_enabled()) {
1171 ShenandoahStringDedup::threads_do(tcl);
1172 }
1173 }
1174
1175 void ShenandoahHeap::print_tracing_info() const {
1176 LogTarget(Info, gc, stats) lt;
1177 if (lt.is_enabled()) {
1178 ResourceMark rm;
1179 LogStream ls(lt);
1180
1181 phase_timings()->print_on(&ls);
1182
1183 ls.cr();
1184 ls.cr();
1185
1186 shenandoah_policy()->print_gc_stats(&ls);
1187
1188 ls.cr();
1189 ls.cr();
1190
1191 if (ShenandoahPacing) {
1192 pacer()->print_on(&ls);
1193 }
1194
1195 ls.cr();
1196 ls.cr();
1197
1198 if (ShenandoahAllocationTrace) {
1199 assert(alloc_tracker() != NULL, "Must be");
1200 alloc_tracker()->print_on(&ls);
1201 } else {
1202 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1203 }
1204 }
1205 }
1206
1207 void ShenandoahHeap::verify(VerifyOption vo) {
1208 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1209 if (ShenandoahVerify) {
1210 verifier()->verify_generic(vo);
1211 } else {
1212 // TODO: Consider allocating verification bitmaps on demand,
1213 // and turn this on unconditionally.
1214 }
1215 }
1216 }
1217 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1218 return _free_set->capacity();
1219 }
1220
1221 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1222 private:
1223 MarkBitMap* _bitmap;
1224 Stack<oop,mtGC>* _oop_stack;
1225
1226 template <class T>
1227 void do_oop_work(T* p) {
1228 T o = RawAccess<>::oop_load(p);
1229 if (!CompressedOops::is_null(o)) {
1230 oop obj = CompressedOops::decode_not_null(o);
1231 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1232 assert(oopDesc::is_oop(obj), "must be a valid oop");
1233 if (!_bitmap->is_marked((HeapWord*) obj)) {
1234 _bitmap->mark((HeapWord*) obj);
1235 _oop_stack->push(obj);
1236 }
1237 }
1238 }
1239 public:
1240 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1241 _bitmap(bitmap), _oop_stack(oop_stack) {}
1242 void do_oop(oop* p) { do_oop_work(p); }
1243 void do_oop(narrowOop* p) { do_oop_work(p); }
1244 };
1245
1246 /*
1247 * This is public API, used in preparation of object_iterate().
1248 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1249 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1250 * control, we call SH::make_tlabs_parsable().
1251 */
1252 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1253 // No-op.
1254 }
1255
1256 /*
1257 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1258 *
1259 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1260 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1261 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1262 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1263 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1264 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1265 * wiped the bitmap in preparation for next marking).
1266 *
1267 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1268 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1269 * is allowed to report dead objects, but is not required to do so.
1270 */
1271 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1272 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1273 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1274 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1275 return;
1276 }
1277
1278 // Reset bitmap
1279 _aux_bit_map.clear();
1280
1281 Stack<oop,mtGC> oop_stack;
1282
1283 // First, we process all GC roots. This populates the work stack with initial objects.
1284 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1285 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1286 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1287 CodeBlobToOopClosure blobs(&oops, false);
1288 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1289
1290 // Work through the oop stack to traverse heap.
1291 while (! oop_stack.is_empty()) {
1292 oop obj = oop_stack.pop();
1293 assert(oopDesc::is_oop(obj), "must be a valid oop");
1294 cl->do_object(obj);
1295 obj->oop_iterate(&oops);
1296 }
1297
1298 assert(oop_stack.is_empty(), "should be empty");
1299
1300 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1301 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1302 }
1303 }
1304
1305 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1306 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1307 object_iterate(cl);
1308 }
1309
1310 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1311 for (size_t i = 0; i < num_regions(); i++) {
1312 ShenandoahHeapRegion* current = get_region(i);
1313 blk->heap_region_do(current);
1314 }
1315 }
1316
1317 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1318 private:
1319 ShenandoahHeap* const _heap;
1320 ShenandoahHeapRegionClosure* const _blk;
1321
1322 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1323 volatile size_t _index;
1324 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1325
1326 public:
1327 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1328 AbstractGangTask("Parallel Region Task"),
1329 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1330
1331 void work(uint worker_id) {
1332 size_t stride = ShenandoahParallelRegionStride;
1333
1334 size_t max = _heap->num_regions();
1335 while (_index < max) {
1336 size_t cur = Atomic::add(stride, &_index) - stride;
1337 size_t start = cur;
1338 size_t end = MIN2(cur + stride, max);
1339 if (start >= max) break;
1340
1341 for (size_t i = cur; i < end; i++) {
1342 ShenandoahHeapRegion* current = _heap->get_region(i);
1343 _blk->heap_region_do(current);
1344 }
1345 }
1346 }
1347 };
1348
1349 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1350 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1351 if (num_regions() > ShenandoahParallelRegionStride) {
1352 ShenandoahParallelHeapRegionTask task(blk);
1353 workers()->run_task(&task);
1354 } else {
1355 heap_region_iterate(blk);
1356 }
1357 }
1358
1359 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1360 private:
1361 ShenandoahMarkingContext* const _ctx;
1362 public:
1363 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1364
1365 void heap_region_do(ShenandoahHeapRegion* r) {
1366 if (r->is_active()) {
1367 r->clear_live_data();
1368 _ctx->capture_top_at_mark_start(r);
1369 } else {
1370 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1371 assert(_ctx->top_at_mark_start(r) == r->top(),
1372 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1373 }
1374 }
1375
1376 bool is_thread_safe() { return true; }
1377 };
1378
1379 void ShenandoahHeap::op_init_mark() {
1380 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1381 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1382
1383 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1384 assert(!marking_context()->is_complete(), "should not be complete");
1385
1386 if (ShenandoahVerify) {
1387 verifier()->verify_before_concmark();
1388 }
1389
1390 if (VerifyBeforeGC) {
1391 Universe::verify();
1392 }
1393
1394 set_concurrent_mark_in_progress(true);
1395 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1396 {
1397 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1398 make_parsable(true);
1399 }
1400
1401 {
1402 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1403 ShenandoahClearLivenessClosure clc;
1404 parallel_heap_region_iterate(&clc);
1405 }
1406
1407 // Make above changes visible to worker threads
1408 OrderAccess::fence();
1409
1410 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1411
1412 if (UseTLAB) {
1413 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1414 resize_tlabs();
1415 }
1416
1417 if (ShenandoahPacing) {
1418 pacer()->setup_for_mark();
1419 }
1420 }
1421
1422 void ShenandoahHeap::op_mark() {
1423 concurrent_mark()->mark_from_roots();
1424 }
1425
1426 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1427 private:
1428 ShenandoahMarkingContext* const _ctx;
1429 public:
1430 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1431
1432 void heap_region_do(ShenandoahHeapRegion* r) {
1433 if (r->is_active()) {
1434 HeapWord *tams = _ctx->top_at_mark_start(r);
1435 HeapWord *top = r->top();
1436 if (top > tams) {
1437 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1438 }
1439 } else {
1440 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1441 assert(_ctx->top_at_mark_start(r) == r->top(),
1442 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1443 }
1444 }
1445
1446 bool is_thread_safe() { return true; }
1447 };
1448
1449 void ShenandoahHeap::op_final_mark() {
1450 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1451
1452 // It is critical that we
1453 // evacuate roots right after finishing marking, so that we don't
1454 // get unmarked objects in the roots.
1455
1456 if (!cancelled_gc()) {
1457 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1458
1459 if (has_forwarded_objects()) {
1460 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1461 }
1462
1463 stop_concurrent_marking();
1464
1465 {
1466 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1467
1468 // All allocations past TAMS are implicitly live, adjust the region data.
1469 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1470 ShenandoahCompleteLivenessClosure cl;
1471 parallel_heap_region_iterate(&cl);
1472 }
1473
1474 {
1475 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1476
1477 make_parsable(true);
1478
1479 trash_cset_regions();
1480
1481 {
1482 ShenandoahHeapLocker locker(lock());
1483 _collection_set->clear();
1484 _free_set->clear();
1485
1486 heuristics()->choose_collection_set(_collection_set);
1487
1488 _free_set->rebuild();
1489 }
1490 }
1491
1492 // If collection set has candidates, start evacuation.
1493 // Otherwise, bypass the rest of the cycle.
1494 if (!collection_set()->is_empty()) {
1495 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1496
1497 if (ShenandoahVerify) {
1498 verifier()->verify_before_evacuation();
1499 }
1500
1501 set_evacuation_in_progress(true);
1502 // From here on, we need to update references.
1503 set_has_forwarded_objects(true);
1504
1505 evacuate_and_update_roots();
1506
1507 if (ShenandoahPacing) {
1508 pacer()->setup_for_evac();
1509 }
1510 } else {
1511 if (ShenandoahVerify) {
1512 verifier()->verify_after_concmark();
1513 }
1514
1515 if (VerifyAfterGC) {
1516 Universe::verify();
1517 }
1518 }
1519
1520 } else {
1521 concurrent_mark()->cancel();
1522 stop_concurrent_marking();
1523
1524 if (process_references()) {
1525 // Abandon reference processing right away: pre-cleaning must have failed.
1526 ReferenceProcessor *rp = ref_processor();
1527 rp->disable_discovery();
1528 rp->abandon_partial_discovery();
1529 rp->verify_no_references_recorded();
1530 }
1531 }
1532 }
1533
1534 void ShenandoahHeap::op_final_evac() {
1535 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1536
1537 set_evacuation_in_progress(false);
1538
1539 retire_and_reset_gclabs();
1540
1541 if (ShenandoahVerify) {
1542 verifier()->verify_after_evacuation();
1543 }
1544
1545 if (VerifyAfterGC) {
1546 Universe::verify();
1547 }
1548 }
1549
1550 void ShenandoahHeap::op_conc_evac() {
1551 ShenandoahEvacuationTask task(this, _collection_set, true);
1552 workers()->run_task(&task);
1553 }
1554
1555 void ShenandoahHeap::op_stw_evac() {
1556 ShenandoahEvacuationTask task(this, _collection_set, false);
1557 workers()->run_task(&task);
1558 }
1559
1560 void ShenandoahHeap::op_updaterefs() {
1561 update_heap_references(true);
1562 }
1563
1564 void ShenandoahHeap::op_cleanup() {
1565 free_set()->recycle_trash();
1566 }
1567
1568 void ShenandoahHeap::op_reset() {
1569 reset_mark_bitmap();
1570 }
1571
1572 void ShenandoahHeap::op_preclean() {
1573 concurrent_mark()->preclean_weak_refs();
1574 }
1575
1576 void ShenandoahHeap::op_init_traversal() {
1577 traversal_gc()->init_traversal_collection();
1578 }
1579
1580 void ShenandoahHeap::op_traversal() {
1581 traversal_gc()->concurrent_traversal_collection();
1582 }
1583
1584 void ShenandoahHeap::op_final_traversal() {
1585 traversal_gc()->final_traversal_collection();
1586 }
1587
1588 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1589 ShenandoahMetricsSnapshot metrics;
1590 metrics.snap_before();
1591
1592 full_gc()->do_it(cause);
1593 if (UseTLAB) {
1594 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1595 resize_all_tlabs();
1596 }
1597
1598 metrics.snap_after();
1599 metrics.print();
1600
1601 if (metrics.is_good_progress("Full GC")) {
1602 _progress_last_gc.set();
1603 } else {
1604 // Nothing to do. Tell the allocation path that we have failed to make
1605 // progress, and it can finally fail.
1606 _progress_last_gc.unset();
1607 }
1608 }
1609
1610 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1611 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1612 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1613 // some phase, we have to upgrade the Degenerate GC to Full GC.
1614
1615 clear_cancelled_gc();
1616
1617 ShenandoahMetricsSnapshot metrics;
1618 metrics.snap_before();
1619
1620 switch (point) {
1621 case _degenerated_traversal:
1622 {
1623 // Drop the collection set. Note: this leaves some already forwarded objects
1624 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1625 // workarounds in ShenandoahTraversalHeuristics.
1626
1627 ShenandoahHeapLocker locker(lock());
1628 collection_set()->clear_current_index();
1629 for (size_t i = 0; i < collection_set()->count(); i++) {
1630 ShenandoahHeapRegion* r = collection_set()->next();
1631 r->make_regular_bypass();
1632 }
1633 collection_set()->clear();
1634 }
1635 op_final_traversal();
1636 op_cleanup();
1637 return;
1638
1639 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1640 // but enters it at different points, depending on which concurrent phase had
1641 // degenerated.
1642
1643 case _degenerated_outside_cycle:
1644 // We have degenerated from outside the cycle, which means something is bad with
1645 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1646 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1647 // we can do the most aggressive degen cycle, which includes processing references and
1648 // class unloading, unless those features are explicitly disabled.
1649 //
1650 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1651 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1652 set_process_references(heuristics()->can_process_references());
1653 set_unload_classes(heuristics()->can_unload_classes());
1654
1655 if (heuristics()->can_do_traversal_gc()) {
1656 // Not possible to degenerate from here, upgrade to Full GC right away.
1657 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1658 op_degenerated_fail();
1659 return;
1660 }
1661
1662 op_reset();
1663
1664 op_init_mark();
1665 if (cancelled_gc()) {
1666 op_degenerated_fail();
1667 return;
1668 }
1669
1670 case _degenerated_mark:
1671 op_final_mark();
1672 if (cancelled_gc()) {
1673 op_degenerated_fail();
1674 return;
1675 }
1676
1677 op_cleanup();
1678
1679 case _degenerated_evac:
1680 // If heuristics thinks we should do the cycle, this flag would be set,
1681 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1682 if (is_evacuation_in_progress()) {
1683
1684 // Degeneration under oom-evac protocol might have left some objects in
1685 // collection set un-evacuated. Restart evacuation from the beginning to
1686 // capture all objects. For all the objects that are already evacuated,
1687 // it would be a simple check, which is supposed to be fast. This is also
1688 // safe to do even without degeneration, as CSet iterator is at beginning
1689 // in preparation for evacuation anyway.
1690 collection_set()->clear_current_index();
1691
1692 op_stw_evac();
1693 if (cancelled_gc()) {
1694 op_degenerated_fail();
1695 return;
1696 }
1697 }
1698
1699 // If heuristics thinks we should do the cycle, this flag would be set,
1700 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1701 if (has_forwarded_objects()) {
1702 op_init_updaterefs();
1703 if (cancelled_gc()) {
1704 op_degenerated_fail();
1705 return;
1706 }
1707 }
1708
1709 case _degenerated_updaterefs:
1710 if (has_forwarded_objects()) {
1711 op_final_updaterefs();
1712 if (cancelled_gc()) {
1713 op_degenerated_fail();
1714 return;
1715 }
1716 }
1717
1718 op_cleanup();
1719 break;
1720
1721 default:
1722 ShouldNotReachHere();
1723 }
1724
1725 if (ShenandoahVerify) {
1726 verifier()->verify_after_degenerated();
1727 }
1728
1729 if (VerifyAfterGC) {
1730 Universe::verify();
1731 }
1732
1733 metrics.snap_after();
1734 metrics.print();
1735
1736 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1737 // because that probably means the heap is overloaded and/or fragmented.
1738 if (!metrics.is_good_progress("Degenerated GC")) {
1739 _progress_last_gc.unset();
1740 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1741 op_degenerated_futile();
1742 } else {
1743 _progress_last_gc.set();
1744 }
1745 }
1746
1747 void ShenandoahHeap::op_degenerated_fail() {
1748 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1749 shenandoah_policy()->record_degenerated_upgrade_to_full();
1750 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1751 }
1752
1753 void ShenandoahHeap::op_degenerated_futile() {
1754 shenandoah_policy()->record_degenerated_upgrade_to_full();
1755 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1756 }
1757
1758 void ShenandoahHeap::stop_concurrent_marking() {
1759 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1760 if (!cancelled_gc()) {
1761 // If we needed to update refs, and concurrent marking has been cancelled,
1762 // we need to finish updating references.
1763 set_has_forwarded_objects(false);
1764 mark_complete_marking_context();
1765 }
1766 set_concurrent_mark_in_progress(false);
1767 }
1768
1769 void ShenandoahHeap::force_satb_flush_all_threads() {
1770 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1771 // No need to flush SATBs
1772 return;
1773 }
1774
1775 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1776 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1777 }
1778 // The threads are not "acquiring" their thread-local data, but it does not
1779 // hurt to "release" the updates here anyway.
1780 OrderAccess::fence();
1781 }
1782
1783 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1784 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1785 ShenandoahThreadLocalData::set_gc_state(t, state);
1786 }
1787 }
1788
1789 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1790 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1791 _gc_state.set_cond(mask, value);
1792 set_gc_state_all_threads(_gc_state.raw_value());
1793 }
1794
1795 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1796 set_gc_state_mask(MARKING, in_progress);
1797 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1798 }
1799
1800 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1801 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1802 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1803 }
1804
1805 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1806 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1807 set_gc_state_mask(EVACUATION, in_progress);
1808 }
1809
1810 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1811 // Initialize Brooks pointer for the next object
1812 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1813 ShenandoahBrooksPointer::initialize(oop(result));
1814 return result;
1815 }
1816
1817 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1818 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1819 }
1820
1821 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1822 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1823 }
1824
1825 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1826 if (CompressedOops::is_null(obj)) {
1827 return false;
1828 }
1829 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1830 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1831 return _mark_context->is_marked(obj);
1832 }
1833
1834 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1835 if (CompressedOops::is_null(obj)) {
1836 return false;
1837 }
1838 shenandoah_assert_not_forwarded(NULL, obj);
1839 return _mark_context->is_marked(obj);
1840 }
1841
1842 void ShenandoahHeap::ref_processing_init() {
1843 assert(_max_workers > 0, "Sanity");
1844
1845 _ref_processor =
1846 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1847 ParallelRefProcEnabled, // MT processing
1848 _max_workers, // Degree of MT processing
1849 true, // MT discovery
1850 _max_workers, // Degree of MT discovery
1851 false, // Reference discovery is not atomic
1852 NULL, // No closure, should be installed before use
1853 true); // Scale worker threads
1854
1855 shenandoah_assert_rp_isalive_not_installed();
1856 }
1857
1858 GCTracer* ShenandoahHeap::tracer() {
1859 return shenandoah_policy()->tracer();
1860 }
1861
1862 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1863 return _free_set->used();
1864 }
1865
1866 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1867 if (try_cancel_gc()) {
1868 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1869 log_info(gc)("%s", msg.buffer());
1870 Events::log(Thread::current(), "%s", msg.buffer());
1871 }
1872 }
1873
1874 uint ShenandoahHeap::max_workers() {
1875 return _max_workers;
1876 }
1877
1878 void ShenandoahHeap::stop() {
1879 // The shutdown sequence should be able to terminate when GC is running.
1880
1881 // Step 0. Notify policy to disable event recording.
1882 _shenandoah_policy->record_shutdown();
1883
1884 // Step 1. Notify control thread that we are in shutdown.
1885 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1886 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1887 control_thread()->prepare_for_graceful_shutdown();
1888
1889 // Step 2. Notify GC workers that we are cancelling GC.
1890 cancel_gc(GCCause::_shenandoah_stop_vm);
1891
1892 // Step 3. Wait until GC worker exits normally.
1893 control_thread()->stop();
1894
1895 // Step 4. Stop String Dedup thread if it is active
1896 if (ShenandoahStringDedup::is_enabled()) {
1897 ShenandoahStringDedup::stop();
1898 }
1899 }
1900
1901 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1902 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1903
1904 ShenandoahGCPhase root_phase(full_gc ?
1905 ShenandoahPhaseTimings::full_gc_purge :
1906 ShenandoahPhaseTimings::purge);
1907
1908 ShenandoahIsAliveSelector alive;
1909 BoolObjectClosure* is_alive = alive.is_alive_closure();
1910
1911 bool purged_class;
1912
1913 // Unload classes and purge SystemDictionary.
1914 {
1915 ShenandoahGCPhase phase(full_gc ?
1916 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1917 ShenandoahPhaseTimings::purge_class_unload);
1918 purged_class = SystemDictionary::do_unloading(gc_timer());
1919 }
1920
1921 {
1922 ShenandoahGCPhase phase(full_gc ?
1923 ShenandoahPhaseTimings::full_gc_purge_par :
1924 ShenandoahPhaseTimings::purge_par);
1925 uint active = _workers->active_workers();
1926 StringDedupUnlinkOrOopsDoClosure dedup_cl(is_alive, NULL);
1927 ParallelCleaningTask unlink_task(is_alive, &dedup_cl, active, purged_class);
1928 _workers->run_task(&unlink_task);
1929 }
1930
1931 {
1932 ShenandoahGCPhase phase(full_gc ?
1933 ShenandoahPhaseTimings::full_gc_purge_cldg :
1934 ShenandoahPhaseTimings::purge_cldg);
1935 ClassLoaderDataGraph::purge();
1936 }
1937 }
1938
1939 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1940 set_gc_state_mask(HAS_FORWARDED, cond);
1941 }
1942
1943 void ShenandoahHeap::set_process_references(bool pr) {
1944 _process_references.set_cond(pr);
1945 }
1946
1947 void ShenandoahHeap::set_unload_classes(bool uc) {
1948 _unload_classes.set_cond(uc);
1949 }
1950
1951 bool ShenandoahHeap::process_references() const {
1952 return _process_references.is_set();
1953 }
1954
1955 bool ShenandoahHeap::unload_classes() const {
1956 return _unload_classes.is_set();
1957 }
1958
1959 address ShenandoahHeap::in_cset_fast_test_addr() {
1960 ShenandoahHeap* heap = ShenandoahHeap::heap();
1961 assert(heap->collection_set() != NULL, "Sanity");
1962 return (address) heap->collection_set()->biased_map_address();
1963 }
1964
1965 address ShenandoahHeap::cancelled_gc_addr() {
1966 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1967 }
1968
1969 address ShenandoahHeap::gc_state_addr() {
1970 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1971 }
1972
1973 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1974 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1975 }
1976
1977 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1978 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1979 }
1980
1981 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1982 _degenerated_gc_in_progress.set_cond(in_progress);
1983 }
1984
1985 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1986 _full_gc_in_progress.set_cond(in_progress);
1987 }
1988
1989 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
1990 assert (is_full_gc_in_progress(), "should be");
1991 _full_gc_move_in_progress.set_cond(in_progress);
1992 }
1993
1994 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1995 set_gc_state_mask(UPDATEREFS, in_progress);
1996 }
1997
1998 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1999 ShenandoahCodeRoots::add_nmethod(nm);
2000 }
2001
2002 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2003 ShenandoahCodeRoots::remove_nmethod(nm);
2004 }
2005
2006 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2007 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2008 ShenandoahHeapLocker locker(lock());
2009 heap_region_containing(o)->make_pinned();
2010 return o;
2011 }
2012
2013 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2014 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2015 ShenandoahHeapLocker locker(lock());
2016 heap_region_containing(o)->make_unpinned();
2017 }
2018
2019 GCTimer* ShenandoahHeap::gc_timer() const {
2020 return _gc_timer;
2021 }
2022
2023 #ifdef ASSERT
2024 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2025 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2026
2027 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2028 if (UseDynamicNumberOfGCThreads ||
2029 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2030 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2031 } else {
2032 // Use ParallelGCThreads inside safepoints
2033 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2034 }
2035 } else {
2036 if (UseDynamicNumberOfGCThreads ||
2037 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2038 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2039 } else {
2040 // Use ConcGCThreads outside safepoints
2041 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2042 }
2043 }
2044 }
2045 #endif
2046
2047 ShenandoahVerifier* ShenandoahHeap::verifier() {
2048 guarantee(ShenandoahVerify, "Should be enabled");
2049 assert (_verifier != NULL, "sanity");
2050 return _verifier;
2051 }
2052
2053 template<class T>
2054 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2055 private:
2056 T cl;
2057 ShenandoahHeap* _heap;
2058 ShenandoahRegionIterator* _regions;
2059 bool _concurrent;
2060 public:
2061 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2062 AbstractGangTask("Concurrent Update References Task"),
2063 cl(T()),
2064 _heap(ShenandoahHeap::heap()),
2065 _regions(regions),
2066 _concurrent(concurrent) {
2067 }
2068
2069 void work(uint worker_id) {
2070 if (_concurrent) {
2071 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2072 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2073 do_work();
2074 } else {
2075 ShenandoahParallelWorkerSession worker_session(worker_id);
2076 do_work();
2077 }
2078 }
2079
2080 private:
2081 void do_work() {
2082 ShenandoahHeapRegion* r = _regions->next();
2083 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2084 while (r != NULL) {
2085 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2086 assert (top_at_start_ur >= r->bottom(), "sanity");
2087 if (r->is_active() && !r->is_cset()) {
2088 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2089 }
2090 if (ShenandoahPacing) {
2091 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2092 }
2093 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2094 return;
2095 }
2096 r = _regions->next();
2097 }
2098 }
2099 };
2100
2101 void ShenandoahHeap::update_heap_references(bool concurrent) {
2102 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2103 workers()->run_task(&task);
2104 }
2105
2106 void ShenandoahHeap::op_init_updaterefs() {
2107 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2108
2109 set_evacuation_in_progress(false);
2110
2111 retire_and_reset_gclabs();
2112
2113 if (ShenandoahVerify) {
2114 verifier()->verify_before_updaterefs();
2115 }
2116
2117 set_update_refs_in_progress(true);
2118 make_parsable(true);
2119 for (uint i = 0; i < num_regions(); i++) {
2120 ShenandoahHeapRegion* r = get_region(i);
2121 r->set_concurrent_iteration_safe_limit(r->top());
2122 }
2123
2124 // Reset iterator.
2125 _update_refs_iterator.reset();
2126
2127 if (ShenandoahPacing) {
2128 pacer()->setup_for_updaterefs();
2129 }
2130 }
2131
2132 void ShenandoahHeap::op_final_updaterefs() {
2133 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2134
2135 // Check if there is left-over work, and finish it
2136 if (_update_refs_iterator.has_next()) {
2137 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2138
2139 // Finish updating references where we left off.
2140 clear_cancelled_gc();
2141 update_heap_references(false);
2142 }
2143
2144 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2145 // everything. On degenerated paths, cancelled gc would not be set anyway.
2146 if (cancelled_gc()) {
2147 clear_cancelled_gc();
2148 }
2149 assert(!cancelled_gc(), "Should have been done right before");
2150
2151 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2152 ShenandoahPhaseTimings::degen_gc_update_roots:
2153 ShenandoahPhaseTimings::final_update_refs_roots);
2154
2155 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2156
2157 trash_cset_regions();
2158 set_has_forwarded_objects(false);
2159 set_update_refs_in_progress(false);
2160
2161 if (ShenandoahVerify) {
2162 verifier()->verify_after_updaterefs();
2163 }
2164
2165 if (VerifyAfterGC) {
2166 Universe::verify();
2167 }
2168
2169 {
2170 ShenandoahHeapLocker locker(lock());
2171 _free_set->rebuild();
2172 }
2173 }
2174
2175 #ifdef ASSERT
2176 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2177 _lock.assert_owned_by_current_thread();
2178 }
2179
2180 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2181 _lock.assert_not_owned_by_current_thread();
2182 }
2183
2184 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2185 _lock.assert_owned_by_current_thread_or_safepoint();
2186 }
2187 #endif
2188
2189 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2190 print_on(st);
2191 print_heap_regions_on(st);
2192 }
2193
2194 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2195 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2196
2197 size_t regions_from = _bitmap_regions_per_slice * slice;
2198 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2199 for (size_t g = regions_from; g < regions_to; g++) {
2200 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2201 if (skip_self && g == r->region_number()) continue;
2202 if (get_region(g)->is_committed()) {
2203 return true;
2204 }
2205 }
2206 return false;
2207 }
2208
2209 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2210 assert_heaplock_owned_by_current_thread();
2211
2212 if (is_bitmap_slice_committed(r, true)) {
2213 // Some other region from the group is already committed, meaning the bitmap
2214 // slice is already committed, we exit right away.
2215 return true;
2216 }
2217
2218 // Commit the bitmap slice:
2219 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2220 size_t off = _bitmap_bytes_per_slice * slice;
2221 size_t len = _bitmap_bytes_per_slice;
2222 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2223 return false;
2224 }
2225 return true;
2226 }
2227
2228 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2229 assert_heaplock_owned_by_current_thread();
2230
2231 if (is_bitmap_slice_committed(r, true)) {
2232 // Some other region from the group is still committed, meaning the bitmap
2233 // slice is should stay committed, exit right away.
2234 return true;
2235 }
2236
2237 // Uncommit the bitmap slice:
2238 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2239 size_t off = _bitmap_bytes_per_slice * slice;
2240 size_t len = _bitmap_bytes_per_slice;
2241 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2242 return false;
2243 }
2244 return true;
2245 }
2246
2247 void ShenandoahHeap::safepoint_synchronize_begin() {
2248 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2249 SuspendibleThreadSet::synchronize();
2250 }
2251 }
2252
2253 void ShenandoahHeap::safepoint_synchronize_end() {
2254 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2255 SuspendibleThreadSet::desynchronize();
2256 }
2257 }
2258
2259 void ShenandoahHeap::vmop_entry_init_mark() {
2260 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2261 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2262 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2263
2264 try_inject_alloc_failure();
2265 VM_ShenandoahInitMark op;
2266 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2267 }
2268
2269 void ShenandoahHeap::vmop_entry_final_mark() {
2270 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2271 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2272 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2273
2274 try_inject_alloc_failure();
2275 VM_ShenandoahFinalMarkStartEvac op;
2276 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2277 }
2278
2279 void ShenandoahHeap::vmop_entry_final_evac() {
2280 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2281 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2282 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2283
2284 VM_ShenandoahFinalEvac op;
2285 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2286 }
2287
2288 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2289 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2290 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2291 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2292
2293 try_inject_alloc_failure();
2294 VM_ShenandoahInitUpdateRefs op;
2295 VMThread::execute(&op);
2296 }
2297
2298 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2299 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2300 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2301 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2302
2303 try_inject_alloc_failure();
2304 VM_ShenandoahFinalUpdateRefs op;
2305 VMThread::execute(&op);
2306 }
2307
2308 void ShenandoahHeap::vmop_entry_init_traversal() {
2309 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2310 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2311 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2312
2313 try_inject_alloc_failure();
2314 VM_ShenandoahInitTraversalGC op;
2315 VMThread::execute(&op);
2316 }
2317
2318 void ShenandoahHeap::vmop_entry_final_traversal() {
2319 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2320 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2321 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2322
2323 try_inject_alloc_failure();
2324 VM_ShenandoahFinalTraversalGC op;
2325 VMThread::execute(&op);
2326 }
2327
2328 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2329 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2330 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2331 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2332
2333 try_inject_alloc_failure();
2334 VM_ShenandoahFullGC op(cause);
2335 VMThread::execute(&op);
2336 }
2337
2338 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2339 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2340 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2341 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2342
2343 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2344 VMThread::execute(°enerated_gc);
2345 }
2346
2347 void ShenandoahHeap::entry_init_mark() {
2348 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2349 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2350 const char* msg = init_mark_event_message();
2351 GCTraceTime(Info, gc) time(msg, gc_timer());
2352 EventMark em("%s", msg);
2353
2354 ShenandoahWorkerScope scope(workers(),
2355 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2356 "init marking");
2357
2358 op_init_mark();
2359 }
2360
2361 void ShenandoahHeap::entry_final_mark() {
2362 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2363 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2364 const char* msg = final_mark_event_message();
2365 GCTraceTime(Info, gc) time(msg, gc_timer());
2366 EventMark em("%s", msg);
2367
2368 ShenandoahWorkerScope scope(workers(),
2369 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2370 "final marking");
2371
2372 op_final_mark();
2373 }
2374
2375 void ShenandoahHeap::entry_final_evac() {
2376 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2377 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2378 static const char* msg = "Pause Final Evac";
2379 GCTraceTime(Info, gc) time(msg, gc_timer());
2380 EventMark em("%s", msg);
2381
2382 op_final_evac();
2383 }
2384
2385 void ShenandoahHeap::entry_init_updaterefs() {
2386 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2387 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2388
2389 static const char* msg = "Pause Init Update Refs";
2390 GCTraceTime(Info, gc) time(msg, gc_timer());
2391 EventMark em("%s", msg);
2392
2393 // No workers used in this phase, no setup required
2394
2395 op_init_updaterefs();
2396 }
2397
2398 void ShenandoahHeap::entry_final_updaterefs() {
2399 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2400 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2401
2402 static const char* msg = "Pause Final Update Refs";
2403 GCTraceTime(Info, gc) time(msg, gc_timer());
2404 EventMark em("%s", msg);
2405
2406 ShenandoahWorkerScope scope(workers(),
2407 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2408 "final reference update");
2409
2410 op_final_updaterefs();
2411 }
2412
2413 void ShenandoahHeap::entry_init_traversal() {
2414 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2415 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2416
2417 static const char* msg = "Pause Init Traversal";
2418 GCTraceTime(Info, gc) time(msg, gc_timer());
2419 EventMark em("%s", msg);
2420
2421 ShenandoahWorkerScope scope(workers(),
2422 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2423 "init traversal");
2424
2425 op_init_traversal();
2426 }
2427
2428 void ShenandoahHeap::entry_final_traversal() {
2429 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2430 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2431
2432 static const char* msg = "Pause Final Traversal";
2433 GCTraceTime(Info, gc) time(msg, gc_timer());
2434 EventMark em("%s", msg);
2435
2436 ShenandoahWorkerScope scope(workers(),
2437 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2438 "final traversal");
2439
2440 op_final_traversal();
2441 }
2442
2443 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2444 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2445 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2446
2447 static const char* msg = "Pause Full";
2448 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2449 EventMark em("%s", msg);
2450
2451 ShenandoahWorkerScope scope(workers(),
2452 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2453 "full gc");
2454
2455 op_full(cause);
2456 }
2457
2458 void ShenandoahHeap::entry_degenerated(int point) {
2459 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2460 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2461
2462 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2463 const char* msg = degen_event_message(dpoint);
2464 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2465 EventMark em("%s", msg);
2466
2467 ShenandoahWorkerScope scope(workers(),
2468 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2469 "stw degenerated gc");
2470
2471 set_degenerated_gc_in_progress(true);
2472 op_degenerated(dpoint);
2473 set_degenerated_gc_in_progress(false);
2474 }
2475
2476 void ShenandoahHeap::entry_mark() {
2477 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2478
2479 const char* msg = conc_mark_event_message();
2480 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2481 EventMark em("%s", msg);
2482
2483 ShenandoahWorkerScope scope(workers(),
2484 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2485 "concurrent marking");
2486
2487 try_inject_alloc_failure();
2488 op_mark();
2489 }
2490
2491 void ShenandoahHeap::entry_evac() {
2492 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2493 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2494
2495 static const char* msg = "Concurrent evacuation";
2496 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2497 EventMark em("%s", msg);
2498
2499 ShenandoahWorkerScope scope(workers(),
2500 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2501 "concurrent evacuation");
2502
2503 try_inject_alloc_failure();
2504 op_conc_evac();
2505 }
2506
2507 void ShenandoahHeap::entry_updaterefs() {
2508 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2509
2510 static const char* msg = "Concurrent update references";
2511 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2512 EventMark em("%s", msg);
2513
2514 ShenandoahWorkerScope scope(workers(),
2515 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2516 "concurrent reference update");
2517
2518 try_inject_alloc_failure();
2519 op_updaterefs();
2520 }
2521 void ShenandoahHeap::entry_cleanup() {
2522 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2523
2524 static const char* msg = "Concurrent cleanup";
2525 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2526 EventMark em("%s", msg);
2527
2528 // This phase does not use workers, no need for setup
2529
2530 try_inject_alloc_failure();
2531 op_cleanup();
2532 }
2533
2534 void ShenandoahHeap::entry_reset() {
2535 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2536
2537 static const char* msg = "Concurrent reset";
2538 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2539 EventMark em("%s", msg);
2540
2541 ShenandoahWorkerScope scope(workers(),
2542 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2543 "concurrent reset");
2544
2545 try_inject_alloc_failure();
2546 op_reset();
2547 }
2548
2549 void ShenandoahHeap::entry_preclean() {
2550 if (ShenandoahPreclean && process_references()) {
2551 static const char* msg = "Concurrent precleaning";
2552 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2553 EventMark em("%s", msg);
2554
2555 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2556
2557 ShenandoahWorkerScope scope(workers(),
2558 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2559 "concurrent preclean",
2560 /* check_workers = */ false);
2561
2562 try_inject_alloc_failure();
2563 op_preclean();
2564 }
2565 }
2566
2567 void ShenandoahHeap::entry_traversal() {
2568 static const char* msg = "Concurrent traversal";
2569 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2570 EventMark em("%s", msg);
2571
2572 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2573
2574 ShenandoahWorkerScope scope(workers(),
2575 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2576 "concurrent traversal");
2577
2578 try_inject_alloc_failure();
2579 op_traversal();
2580 }
2581
2582 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2583 static const char *msg = "Concurrent uncommit";
2584 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2585 EventMark em("%s", msg);
2586
2587 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2588
2589 op_uncommit(shrink_before);
2590 }
2591
2592 void ShenandoahHeap::try_inject_alloc_failure() {
2593 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2594 _inject_alloc_failure.set();
2595 os::naked_short_sleep(1);
2596 if (cancelled_gc()) {
2597 log_info(gc)("Allocation failure was successfully injected");
2598 }
2599 }
2600 }
2601
2602 bool ShenandoahHeap::should_inject_alloc_failure() {
2603 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2604 }
2605
2606 void ShenandoahHeap::initialize_serviceability() {
2607 _memory_pool = new ShenandoahMemoryPool(this);
2608 _cycle_memory_manager.add_pool(_memory_pool);
2609 _stw_memory_manager.add_pool(_memory_pool);
2610 }
2611
2612 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2613 GrowableArray<GCMemoryManager*> memory_managers(2);
2614 memory_managers.append(&_cycle_memory_manager);
2615 memory_managers.append(&_stw_memory_manager);
2616 return memory_managers;
2617 }
2618
2619 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2620 GrowableArray<MemoryPool*> memory_pools(1);
2621 memory_pools.append(_memory_pool);
2622 return memory_pools;
2623 }
2624
2625 void ShenandoahHeap::enter_evacuation() {
2626 _oom_evac_handler.enter_evacuation();
2627 }
2628
2629 void ShenandoahHeap::leave_evacuation() {
2630 _oom_evac_handler.leave_evacuation();
2631 }
2632
2633 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2634 _heap(ShenandoahHeap::heap()),
2635 _index(0) {}
2636
2637 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2638 _heap(heap),
2639 _index(0) {}
2640
2641 void ShenandoahRegionIterator::reset() {
2642 _index = 0;
2643 }
2644
2645 bool ShenandoahRegionIterator::has_next() const {
2646 return _index < _heap->num_regions();
2647 }
2648
2649 char ShenandoahHeap::gc_state() const {
2650 return _gc_state.raw_value();
2651 }
2652
2653 void ShenandoahHeap::deduplicate_string(oop str) {
2654 assert(java_lang_String::is_instance(str), "invariant");
2655
2656 if (ShenandoahStringDedup::is_enabled()) {
2657 ShenandoahStringDedup::deduplicate(str);
2658 }
2659 }
2660
2661 const char* ShenandoahHeap::init_mark_event_message() const {
2662 bool update_refs = has_forwarded_objects();
2663 bool proc_refs = process_references();
2664 bool unload_cls = unload_classes();
2665
2666 if (update_refs && proc_refs && unload_cls) {
2667 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2668 } else if (update_refs && proc_refs) {
2669 return "Pause Init Mark (update refs) (process weakrefs)";
2670 } else if (update_refs && unload_cls) {
2671 return "Pause Init Mark (update refs) (unload classes)";
2672 } else if (proc_refs && unload_cls) {
2673 return "Pause Init Mark (process weakrefs) (unload classes)";
2674 } else if (update_refs) {
2675 return "Pause Init Mark (update refs)";
2676 } else if (proc_refs) {
2677 return "Pause Init Mark (process weakrefs)";
2678 } else if (unload_cls) {
2679 return "Pause Init Mark (unload classes)";
2680 } else {
2681 return "Pause Init Mark";
2682 }
2683 }
2684
2685 const char* ShenandoahHeap::final_mark_event_message() const {
2686 bool update_refs = has_forwarded_objects();
2687 bool proc_refs = process_references();
2688 bool unload_cls = unload_classes();
2689
2690 if (update_refs && proc_refs && unload_cls) {
2691 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2692 } else if (update_refs && proc_refs) {
2693 return "Pause Final Mark (update refs) (process weakrefs)";
2694 } else if (update_refs && unload_cls) {
2695 return "Pause Final Mark (update refs) (unload classes)";
2696 } else if (proc_refs && unload_cls) {
2697 return "Pause Final Mark (process weakrefs) (unload classes)";
2698 } else if (update_refs) {
2699 return "Pause Final Mark (update refs)";
2700 } else if (proc_refs) {
2701 return "Pause Final Mark (process weakrefs)";
2702 } else if (unload_cls) {
2703 return "Pause Final Mark (unload classes)";
2704 } else {
2705 return "Pause Final Mark";
2706 }
2707 }
2708
2709 const char* ShenandoahHeap::conc_mark_event_message() const {
2710 bool update_refs = has_forwarded_objects();
2711 bool proc_refs = process_references();
2712 bool unload_cls = unload_classes();
2713
2714 if (update_refs && proc_refs && unload_cls) {
2715 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2716 } else if (update_refs && proc_refs) {
2717 return "Concurrent marking (update refs) (process weakrefs)";
2718 } else if (update_refs && unload_cls) {
2719 return "Concurrent marking (update refs) (unload classes)";
2720 } else if (proc_refs && unload_cls) {
2721 return "Concurrent marking (process weakrefs) (unload classes)";
2722 } else if (update_refs) {
2723 return "Concurrent marking (update refs)";
2724 } else if (proc_refs) {
2725 return "Concurrent marking (process weakrefs)";
2726 } else if (unload_cls) {
2727 return "Concurrent marking (unload classes)";
2728 } else {
2729 return "Concurrent marking";
2730 }
2731 }
2732
2733 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2734 switch (point) {
2735 case _degenerated_unset:
2736 return "Pause Degenerated GC (<UNSET>)";
2737 case _degenerated_traversal:
2738 return "Pause Degenerated GC (Traversal)";
2739 case _degenerated_outside_cycle:
2740 return "Pause Degenerated GC (Outside of Cycle)";
2741 case _degenerated_mark:
2742 return "Pause Degenerated GC (Mark)";
2743 case _degenerated_evac:
2744 return "Pause Degenerated GC (Evacuation)";
2745 case _degenerated_updaterefs:
2746 return "Pause Degenerated GC (Update Refs)";
2747 default:
2748 ShouldNotReachHere();
2749 return "ERROR";
2750 }
2751 }
2752
2753 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2754 #ifdef ASSERT
2755 assert(worker_id < _max_workers, "sanity");
2756 for (uint i = 0; i < num_regions(); i++) {
2757 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2758 }
2759 #endif
2760 return _liveness_cache[worker_id];
2761 }
2762
2763 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2764 assert(worker_id < _max_workers, "sanity");
2765 jushort* ld = _liveness_cache[worker_id];
2766 for (uint i = 0; i < num_regions(); i++) {
2767 ShenandoahHeapRegion* r = get_region(i);
2768 jushort live = ld[i];
2769 if (live > 0) {
2770 r->increase_live_data_gc_words(live);
2771 ld[i] = 0;
2772 }
2773 }
2774 }
2775
2776 size_t ShenandoahHeap::obj_size(oop obj) const {
2777 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2778 }
2779
2780 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2781 return ShenandoahBrooksPointer::byte_size();
2782 }
2783
2784 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2785 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2786 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2787 }