1 /*
2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/memAllocator.hpp"
30 #include "gc/shared/parallelCleaning.hpp"
31 #include "gc/shared/plab.hpp"
32
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahBrooksPointer.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
37 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
47 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
48 #include "gc/shenandoah/shenandoahMetrics.hpp"
49 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
50 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
51 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
52 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
53 #include "gc/shenandoah/shenandoahStringDedup.hpp"
54 #include "gc/shenandoah/shenandoahUtils.hpp"
55 #include "gc/shenandoah/shenandoahVerifier.hpp"
56 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
57 #include "gc/shenandoah/shenandoahVMOperations.hpp"
58 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
59 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
66
67 #include "memory/metaspace.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/safepointMechanism.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/mallocTracker.hpp"
72
73 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
74
75 #ifdef ASSERT
76 template <class T>
77 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
78 T o = RawAccess<>::oop_load(p);
79 if (! CompressedOops::is_null(o)) {
80 oop obj = CompressedOops::decode_not_null(o);
81 shenandoah_assert_not_forwarded(p, obj);
82 }
83 }
84
85 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
86 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
87 #endif
88
89 class ShenandoahPretouchTask : public AbstractGangTask {
90 private:
91 ShenandoahRegionIterator _regions;
92 const size_t _bitmap_size;
93 const size_t _page_size;
94 char* _bitmap_base;
95 public:
96 ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
97 AbstractGangTask("Shenandoah PreTouch"),
98 _bitmap_size(bitmap_size),
99 _page_size(page_size),
100 _bitmap_base(bitmap_base) {
101 }
102
103 virtual void work(uint worker_id) {
104 ShenandoahHeapRegion* r = _regions.next();
105 while (r != NULL) {
106 os::pretouch_memory(r->bottom(), r->end(), _page_size);
107
108 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
109 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
110 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
111
112 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
113
114 r = _regions.next();
115 }
116 }
117 };
118
119 jint ShenandoahHeap::initialize() {
120 ShenandoahBrooksPointer::initial_checks();
121
122 initialize_heuristics();
123
124 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
125 size_t max_byte_size = collector_policy()->max_heap_byte_size();
126 size_t heap_alignment = collector_policy()->heap_alignment();
127
128 if (ShenandoahAlwaysPreTouch) {
129 // Enabled pre-touch means the entire heap is committed right away.
130 init_byte_size = max_byte_size;
131 }
132
133 Universe::check_alignment(max_byte_size,
134 ShenandoahHeapRegion::region_size_bytes(),
135 "shenandoah heap");
136 Universe::check_alignment(init_byte_size,
137 ShenandoahHeapRegion::region_size_bytes(),
138 "shenandoah heap");
139
140 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
141 heap_alignment);
142 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
143
144 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
145
146 _num_regions = ShenandoahHeapRegion::region_count();
147
148 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
149 num_committed_regions = MIN2(num_committed_regions, _num_regions);
150 assert(num_committed_regions <= _num_regions, "sanity");
151
152 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
153 _committed = _initial_size;
154
155 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
156 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
157 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
158 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
159 }
160
161 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
162 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
163
164 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
165 _free_set = new ShenandoahFreeSet(this, _num_regions);
166
167 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
168
169 if (ShenandoahPacing) {
170 _pacer = new ShenandoahPacer(this);
171 _pacer->setup_for_idle();
172 } else {
173 _pacer = NULL;
174 }
175
176 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
177 "misaligned heap: " PTR_FORMAT, p2i(base()));
178
179 // The call below uses stuff (the SATB* things) that are in G1, but probably
180 // belong into a shared location.
181 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
182 SATB_Q_CBL_mon,
183 20 /* G1SATBProcessCompletedThreshold */,
184 60 /* G1SATBBufferEnqueueingThresholdPercent */);
185
186 // Reserve space for prev and next bitmap.
187 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
188 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
189 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
190 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
191
192 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
193
194 guarantee(bitmap_bytes_per_region != 0,
195 "Bitmap bytes per region should not be zero");
196 guarantee(is_power_of_2(bitmap_bytes_per_region),
197 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
198
199 if (bitmap_page_size > bitmap_bytes_per_region) {
200 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
201 _bitmap_bytes_per_slice = bitmap_page_size;
202 } else {
203 _bitmap_regions_per_slice = 1;
204 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
205 }
206
207 guarantee(_bitmap_regions_per_slice >= 1,
208 "Should have at least one region per slice: " SIZE_FORMAT,
209 _bitmap_regions_per_slice);
210
211 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
212 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
213 _bitmap_bytes_per_slice, bitmap_page_size);
214
215 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
216 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
217 _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
218
219 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
220 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
221 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
222 os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
223 "couldn't allocate initial bitmap");
224
225 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
226
227 if (ShenandoahVerify) {
228 ReservedSpace verify_bitmap(_bitmap_size, page_size);
229 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
230 "couldn't allocate verification bitmap");
231 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
232 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
233 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
234 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
235 }
236
237 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
238
239 {
240 ShenandoahHeapLocker locker(lock());
241 for (size_t i = 0; i < _num_regions; i++) {
242 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
243 (HeapWord*) pgc_rs.base() + reg_size_words * i,
244 reg_size_words,
245 i,
246 i < num_committed_regions);
247
248 _marking_context->initialize_top_at_mark_start(r);
249 _regions[i] = r;
250 assert(!collection_set()->is_in(i), "New region should not be in collection set");
251 }
252
253 // Initialize to complete
254 _marking_context->mark_complete();
255
256 _free_set->rebuild();
257 }
258
259 if (ShenandoahAlwaysPreTouch) {
260 assert (!AlwaysPreTouch, "Should have been overridden");
261
262 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
263 // before initialize() below zeroes it with initializing thread. For any given region,
264 // we touch the region and the corresponding bitmaps from the same thread.
265 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
266
267 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
268 _num_regions, page_size);
269 ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
270 _workers->run_task(&cl);
271 }
272
273 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
274 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
275 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
276 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
277 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
278
279 _traversal_gc = heuristics()->can_do_traversal_gc() ?
280 new ShenandoahTraversalGC(this, _num_regions) :
281 NULL;
282
283 _monitoring_support = new ShenandoahMonitoringSupport(this);
284
285 _phase_timings = new ShenandoahPhaseTimings();
286
287 if (ShenandoahAllocationTrace) {
288 _alloc_tracker = new ShenandoahAllocTracker();
289 }
290
291 ShenandoahStringDedup::initialize();
292
293 _control_thread = new ShenandoahControlThread();
294
295 ShenandoahCodeRoots::initialize();
296
297 log_info(gc, init)("Safepointing mechanism: %s",
298 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
299 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
300
301 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
302 for (uint worker = 0; worker < _max_workers; worker++) {
303 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
304 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
305 }
306
307 return JNI_OK;
308 }
309
310 void ShenandoahHeap::initialize_heuristics() {
311 if (ShenandoahGCHeuristics != NULL) {
312 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
313 _heuristics = new ShenandoahAggressiveHeuristics();
314 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
315 _heuristics = new ShenandoahStaticHeuristics();
316 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
317 _heuristics = new ShenandoahAdaptiveHeuristics();
318 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
319 _heuristics = new ShenandoahPassiveHeuristics();
320 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
321 _heuristics = new ShenandoahCompactHeuristics();
322 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
323 _heuristics = new ShenandoahTraversalHeuristics();
324 } else {
325 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
326 }
327
328 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
329 vm_exit_during_initialization(
330 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
331 _heuristics->name()));
332 }
333 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
334 vm_exit_during_initialization(
335 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
336 _heuristics->name()));
337 }
338
339 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
340 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
341 }
342 log_info(gc, init)("Shenandoah heuristics: %s",
343 _heuristics->name());
344 } else {
345 ShouldNotReachHere();
346 }
347
348 }
349
350 #ifdef _MSC_VER
351 #pragma warning( push )
352 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
353 #endif
354
355 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
356 CollectedHeap(),
357 _initial_size(0),
358 _used(0),
359 _committed(0),
360 _bytes_allocated_since_gc_start(0),
361 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
362 _workers(NULL),
363 _safepoint_workers(NULL),
364 _num_regions(0),
365 _regions(NULL),
366 _update_refs_iterator(this),
367 _control_thread(NULL),
368 _shenandoah_policy(policy),
369 _heuristics(NULL),
370 _free_set(NULL),
371 _scm(new ShenandoahConcurrentMark()),
372 _traversal_gc(NULL),
373 _full_gc(new ShenandoahMarkCompact()),
374 _pacer(NULL),
375 _verifier(NULL),
376 _alloc_tracker(NULL),
377 _phase_timings(NULL),
378 _monitoring_support(NULL),
379 _memory_pool(NULL),
380 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
381 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
382 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
383 _soft_ref_policy(),
384 _ref_processor(NULL),
385 _marking_context(NULL),
386 _collection_set(NULL)
387 {
388 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
389 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
390
391 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
392
393 _max_workers = MAX2(_max_workers, 1U);
394 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
395 /* are_GC_task_threads */true,
396 /* are_ConcurrentGC_threads */false);
397 if (_workers == NULL) {
398 vm_exit_during_initialization("Failed necessary allocation.");
399 } else {
400 _workers->initialize_workers();
401 }
402
403 if (ShenandoahParallelSafepointThreads > 1) {
404 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
405 ShenandoahParallelSafepointThreads,
406 false, false);
407 _safepoint_workers->initialize_workers();
408 }
409 }
410
411 #ifdef _MSC_VER
412 #pragma warning( pop )
413 #endif
414
415 class ShenandoahResetBitmapTask : public AbstractGangTask {
416 private:
417 ShenandoahRegionIterator _regions;
418
419 public:
420 ShenandoahResetBitmapTask() :
421 AbstractGangTask("Parallel Reset Bitmap Task") {}
422
423 void work(uint worker_id) {
424 ShenandoahHeapRegion* region = _regions.next();
425 ShenandoahHeap* heap = ShenandoahHeap::heap();
426 ShenandoahMarkingContext* const ctx = heap->marking_context();
427 while (region != NULL) {
428 if (heap->is_bitmap_slice_committed(region)) {
429 ctx->clear_bitmap(region);
430 }
431 region = _regions.next();
432 }
433 }
434 };
435
436 void ShenandoahHeap::reset_mark_bitmap() {
437 assert_gc_workers(_workers->active_workers());
438 mark_incomplete_marking_context();
439
440 ShenandoahResetBitmapTask task;
441 _workers->run_task(&task);
442 }
443
444 void ShenandoahHeap::print_on(outputStream* st) const {
445 st->print_cr("Shenandoah Heap");
446 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
447 capacity() / K, committed() / K, used() / K);
448 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
449 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
450
451 st->print("Status: ");
452 if (has_forwarded_objects()) st->print("has forwarded objects, ");
453 if (is_concurrent_mark_in_progress()) st->print("marking, ");
454 if (is_evacuation_in_progress()) st->print("evacuating, ");
455 if (is_update_refs_in_progress()) st->print("updating refs, ");
456 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
457 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
458 if (is_full_gc_in_progress()) st->print("full gc, ");
459 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
460
461 if (cancelled_gc()) {
462 st->print("cancelled");
463 } else {
464 st->print("not cancelled");
465 }
466 st->cr();
467
468 st->print_cr("Reserved region:");
469 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
470 p2i(reserved_region().start()),
471 p2i(reserved_region().end()));
472
473 st->cr();
474 MetaspaceUtils::print_on(st);
475
476 if (Verbose) {
477 print_heap_regions_on(st);
478 }
479 }
480
481 class ShenandoahInitGCLABClosure : public ThreadClosure {
482 public:
483 void do_thread(Thread* thread) {
484 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
485 ShenandoahThreadLocalData::initialize_gclab(thread);
486 }
487 }
488 };
489
490 void ShenandoahHeap::post_initialize() {
491 CollectedHeap::post_initialize();
492 MutexLocker ml(Threads_lock);
493
494 ShenandoahInitGCLABClosure init_gclabs;
495 Threads::threads_do(&init_gclabs);
496 _workers->threads_do(&init_gclabs);
497 _safepoint_workers->threads_do(&init_gclabs);
498
499 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
500 // Now, we will let WorkGang to initialize gclab when new worker is created.
501 _workers->set_initialize_gclab();
502
503 _scm->initialize(_max_workers);
504 _full_gc->initialize(_gc_timer);
505
506 ref_processing_init();
507
508 _heuristics->initialize();
509 }
510
511 size_t ShenandoahHeap::used() const {
512 return OrderAccess::load_acquire(&_used);
513 }
514
515 size_t ShenandoahHeap::committed() const {
516 OrderAccess::acquire();
517 return _committed;
518 }
519
520 void ShenandoahHeap::increase_committed(size_t bytes) {
521 assert_heaplock_or_safepoint();
522 _committed += bytes;
523 }
524
525 void ShenandoahHeap::decrease_committed(size_t bytes) {
526 assert_heaplock_or_safepoint();
527 _committed -= bytes;
528 }
529
530 void ShenandoahHeap::increase_used(size_t bytes) {
531 Atomic::add(bytes, &_used);
532 }
533
534 void ShenandoahHeap::set_used(size_t bytes) {
535 OrderAccess::release_store_fence(&_used, bytes);
536 }
537
538 void ShenandoahHeap::decrease_used(size_t bytes) {
539 assert(used() >= bytes, "never decrease heap size by more than we've left");
540 Atomic::sub(bytes, &_used);
541 }
542
543 void ShenandoahHeap::increase_allocated(size_t bytes) {
544 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
545 }
546
547 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
548 size_t bytes = words * HeapWordSize;
549 if (!waste) {
550 increase_used(bytes);
551 }
552 increase_allocated(bytes);
553 if (ShenandoahPacing) {
554 control_thread()->pacing_notify_alloc(words);
555 if (waste) {
556 pacer()->claim_for_alloc(words, true);
557 }
558 }
559 }
560
561 size_t ShenandoahHeap::capacity() const {
562 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
563 }
564
565 size_t ShenandoahHeap::max_capacity() const {
566 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
567 }
568
569 size_t ShenandoahHeap::initial_capacity() const {
570 return _initial_size;
571 }
572
573 bool ShenandoahHeap::is_in(const void* p) const {
574 HeapWord* heap_base = (HeapWord*) base();
575 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
576 return p >= heap_base && p < last_region_end;
577 }
578
579 void ShenandoahHeap::op_uncommit(double shrink_before) {
580 assert (ShenandoahUncommit, "should be enabled");
581
582 size_t count = 0;
583 for (size_t i = 0; i < num_regions(); i++) {
584 ShenandoahHeapRegion* r = get_region(i);
585 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
586 ShenandoahHeapLocker locker(lock());
587 if (r->is_empty_committed()) {
588 r->make_uncommitted();
589 count++;
590 }
591 }
592 SpinPause(); // allow allocators to take the lock
593 }
594
595 if (count > 0) {
596 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
597 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
598 control_thread()->notify_heap_changed();
599 }
600 }
601
602 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
603 // New object should fit the GCLAB size
604 size_t min_size = MAX2(size, PLAB::min_size());
605
606 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
607 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
608 new_size = MIN2(new_size, PLAB::max_size());
609 new_size = MAX2(new_size, PLAB::min_size());
610
611 // Record new heuristic value even if we take any shortcut. This captures
612 // the case when moderately-sized objects always take a shortcut. At some point,
613 // heuristics should catch up with them.
614 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
615
616 if (new_size < size) {
617 // New size still does not fit the object. Fall back to shared allocation.
618 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
619 return NULL;
620 }
621
622 // Retire current GCLAB, and allocate a new one.
623 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
624 gclab->retire();
625
626 size_t actual_size = 0;
627 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
628 if (gclab_buf == NULL) {
629 return NULL;
630 }
631
632 assert (size <= actual_size, "allocation should fit");
633
634 if (ZeroTLAB) {
635 // ..and clear it.
636 Copy::zero_to_words(gclab_buf, actual_size);
637 } else {
638 // ...and zap just allocated object.
639 #ifdef ASSERT
640 // Skip mangling the space corresponding to the object header to
641 // ensure that the returned space is not considered parsable by
642 // any concurrent GC thread.
643 size_t hdr_size = oopDesc::header_size();
644 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
645 #endif // ASSERT
646 }
647 gclab->set_buf(gclab_buf, actual_size);
648 return gclab->allocate(size);
649 }
650
651 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
652 size_t requested_size,
653 size_t* actual_size) {
654 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
655 HeapWord* res = allocate_memory(req);
656 if (res != NULL) {
657 *actual_size = req.actual_size();
658 } else {
659 *actual_size = 0;
660 }
661 return res;
662 }
663
664 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
665 size_t word_size,
666 size_t* actual_size) {
667 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
668 HeapWord* res = allocate_memory(req);
669 if (res != NULL) {
670 *actual_size = req.actual_size();
671 } else {
672 *actual_size = 0;
673 }
674 return res;
675 }
676
677 ShenandoahHeap* ShenandoahHeap::heap() {
678 CollectedHeap* heap = Universe::heap();
679 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
680 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
681 return (ShenandoahHeap*) heap;
682 }
683
684 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
685 CollectedHeap* heap = Universe::heap();
686 return (ShenandoahHeap*) heap;
687 }
688
689 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
690 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
691
692 intptr_t pacer_epoch = 0;
693 bool in_new_region = false;
694 HeapWord* result = NULL;
695
696 if (req.is_mutator_alloc()) {
697 if (ShenandoahPacing) {
698 pacer()->pace_for_alloc(req.size());
699 pacer_epoch = pacer()->epoch();
700 }
701
702 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
703 result = allocate_memory_under_lock(req, in_new_region);
704 }
705
706 // Allocation failed, block until control thread reacted, then retry allocation.
707 //
708 // It might happen that one of the threads requesting allocation would unblock
709 // way later after GC happened, only to fail the second allocation, because
710 // other threads have already depleted the free storage. In this case, a better
711 // strategy is to try again, as long as GC makes progress.
712 //
713 // Then, we need to make sure the allocation was retried after at least one
714 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
715
716 size_t tries = 0;
717
718 while (result == NULL && _progress_last_gc.is_set()) {
719 tries++;
720 control_thread()->handle_alloc_failure(req.size());
721 result = allocate_memory_under_lock(req, in_new_region);
722 }
723
724 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
725 tries++;
726 control_thread()->handle_alloc_failure(req.size());
727 result = allocate_memory_under_lock(req, in_new_region);
728 }
729
730 } else {
731 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
732 result = allocate_memory_under_lock(req, in_new_region);
733 // Do not call handle_alloc_failure() here, because we cannot block.
734 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
735 }
736
737 if (in_new_region) {
738 control_thread()->notify_heap_changed();
739 }
740
741 if (result != NULL) {
742 size_t requested = req.size();
743 size_t actual = req.actual_size();
744
745 assert (req.is_lab_alloc() || (requested == actual),
746 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
747 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
748
749 if (req.is_mutator_alloc()) {
750 notify_mutator_alloc_words(actual, false);
751
752 // If we requested more than we were granted, give the rest back to pacer.
753 // This only matters if we are in the same pacing epoch: do not try to unpace
754 // over the budget for the other phase.
755 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
756 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
757 }
758 } else {
759 increase_used(actual*HeapWordSize);
760 }
761 }
762
763 return result;
764 }
765
766 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
767 ShenandoahHeapLocker locker(lock());
768 return _free_set->allocate(req, in_new_region);
769 }
770
771 class ShenandoahMemAllocator : public MemAllocator {
772 private:
773 MemAllocator& _initializer;
774 public:
775 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
776 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
777 _initializer(initializer) {}
778
779 protected:
780 virtual HeapWord* mem_allocate(Allocation& allocation) const {
781 HeapWord* result = MemAllocator::mem_allocate(allocation);
782 // Initialize brooks-pointer
783 if (result != NULL) {
784 result += ShenandoahBrooksPointer::word_size();
785 ShenandoahBrooksPointer::initialize(oop(result));
786 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
787 }
788 return result;
789 }
790
791 virtual oop initialize(HeapWord* mem) const {
792 return _initializer.initialize(mem);
793 }
794 };
795
796 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
797 ObjAllocator initializer(klass, size, THREAD);
798 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
799 return allocator.allocate();
800 }
801
802 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
803 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
804 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
805 return allocator.allocate();
806 }
807
808 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
809 ClassAllocator initializer(klass, size, THREAD);
810 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
811 return allocator.allocate();
812 }
813
814 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
815 bool* gc_overhead_limit_was_exceeded) {
816 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
817 return allocate_memory(req);
818 }
819
820 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
821 size_t size,
822 Metaspace::MetadataType mdtype) {
823 MetaWord* result;
824
825 // Inform metaspace OOM to GC heuristics if class unloading is possible.
826 if (heuristics()->can_unload_classes()) {
827 ShenandoahHeuristics* h = heuristics();
828 h->record_metaspace_oom();
829 }
830
831 // Expand and retry allocation
832 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
833 if (result != NULL) {
834 return result;
835 }
836
837 // Start full GC
838 collect(GCCause::_metadata_GC_clear_soft_refs);
839
840 // Retry allocation
841 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
842 if (result != NULL) {
843 return result;
844 }
845
846 // Expand and retry allocation
847 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
848 if (result != NULL) {
849 return result;
850 }
851
852 // Out of memory
853 return NULL;
854 }
855
856 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
857 HeapWord* obj = tlab_post_allocation_setup(start);
858 CollectedHeap::fill_with_object(obj, end);
859 }
860
861 size_t ShenandoahHeap::min_dummy_object_size() const {
862 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
863 }
864
865 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
866 private:
867 ShenandoahHeap* _heap;
868 Thread* _thread;
869 public:
870 ShenandoahEvacuateUpdateRootsClosure() :
871 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
872 }
873
874 private:
875 template <class T>
876 void do_oop_work(T* p) {
877 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
878
879 T o = RawAccess<>::oop_load(p);
880 if (! CompressedOops::is_null(o)) {
881 oop obj = CompressedOops::decode_not_null(o);
882 if (_heap->in_collection_set(obj)) {
883 shenandoah_assert_marked(p, obj);
884 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
885 if (oopDesc::equals_raw(resolved, obj)) {
886 resolved = _heap->evacuate_object(obj, _thread);
887 }
888 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
889 }
890 }
891 }
892
893 public:
894 void do_oop(oop* p) {
895 do_oop_work(p);
896 }
897 void do_oop(narrowOop* p) {
898 do_oop_work(p);
899 }
900 };
901
902 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
903 private:
904 ShenandoahHeap* const _heap;
905 Thread* const _thread;
906 public:
907 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
908 _heap(heap), _thread(Thread::current()) {}
909
910 void do_object(oop p) {
911 shenandoah_assert_marked(NULL, p);
912 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
913 _heap->evacuate_object(p, _thread);
914 }
915 }
916 };
917
918 class ShenandoahEvacuationTask : public AbstractGangTask {
919 private:
920 ShenandoahHeap* const _sh;
921 ShenandoahCollectionSet* const _cs;
922 bool _concurrent;
923 public:
924 ShenandoahEvacuationTask(ShenandoahHeap* sh,
925 ShenandoahCollectionSet* cs,
926 bool concurrent) :
927 AbstractGangTask("Parallel Evacuation Task"),
928 _sh(sh),
929 _cs(cs),
930 _concurrent(concurrent)
931 {}
932
933 void work(uint worker_id) {
934 if (_concurrent) {
935 ShenandoahConcurrentWorkerSession worker_session(worker_id);
936 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
937 ShenandoahEvacOOMScope oom_evac_scope;
938 do_work();
939 } else {
940 ShenandoahParallelWorkerSession worker_session(worker_id);
941 ShenandoahEvacOOMScope oom_evac_scope;
942 do_work();
943 }
944 }
945
946 private:
947 void do_work() {
948 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
949 ShenandoahHeapRegion* r;
950 while ((r =_cs->claim_next()) != NULL) {
951 assert(r->has_live(), "all-garbage regions are reclaimed early");
952 _sh->marked_object_iterate(r, &cl);
953
954 if (ShenandoahPacing) {
955 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
956 }
957
958 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
959 break;
960 }
961 }
962 }
963 };
964
965 void ShenandoahHeap::trash_cset_regions() {
966 ShenandoahHeapLocker locker(lock());
967
968 ShenandoahCollectionSet* set = collection_set();
969 ShenandoahHeapRegion* r;
970 set->clear_current_index();
971 while ((r = set->next()) != NULL) {
972 r->make_trash();
973 }
974 collection_set()->clear();
975 }
976
977 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
978 st->print_cr("Heap Regions:");
979 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
980 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
981 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
982 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
983
984 for (size_t i = 0; i < num_regions(); i++) {
985 get_region(i)->print_on(st);
986 }
987 }
988
989 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
990 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
991
992 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
993 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
994 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
995 size_t index = start->region_number() + required_regions - 1;
996
997 assert(!start->has_live(), "liveness must be zero");
998
999 for(size_t i = 0; i < required_regions; i++) {
1000 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1001 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1002 ShenandoahHeapRegion* region = get_region(index --);
1003
1004 assert(region->is_humongous(), "expect correct humongous start or continuation");
1005 assert(!region->is_cset(), "Humongous region should not be in collection set");
1006
1007 region->make_trash_immediate();
1008 }
1009 }
1010
1011 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1012 public:
1013 void do_thread(Thread* thread) {
1014 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1015 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1016 gclab->retire();
1017 }
1018 };
1019
1020 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1021 if (UseTLAB) {
1022 CollectedHeap::ensure_parsability(retire_tlabs);
1023 }
1024 ShenandoahRetireGCLABClosure cl;
1025 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1026 cl.do_thread(t);
1027 }
1028 workers()->threads_do(&cl);
1029 _safepoint_workers->threads_do(&cl);
1030 }
1031
1032 void ShenandoahHeap::resize_tlabs() {
1033 CollectedHeap::resize_all_tlabs();
1034 }
1035
1036 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1037 private:
1038 ShenandoahRootEvacuator* _rp;
1039
1040 public:
1041 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1042 AbstractGangTask("Shenandoah evacuate and update roots"),
1043 _rp(rp) {}
1044
1045 void work(uint worker_id) {
1046 ShenandoahParallelWorkerSession worker_session(worker_id);
1047 ShenandoahEvacOOMScope oom_evac_scope;
1048 ShenandoahEvacuateUpdateRootsClosure cl;
1049
1050 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1051 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1052 }
1053 };
1054
1055 void ShenandoahHeap::evacuate_and_update_roots() {
1056 #if defined(COMPILER2) || INCLUDE_JVMCI
1057 DerivedPointerTable::clear();
1058 #endif
1059 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1060
1061 {
1062 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1063 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1064 workers()->run_task(&roots_task);
1065 }
1066
1067 #if defined(COMPILER2) || INCLUDE_JVMCI
1068 DerivedPointerTable::update_pointers();
1069 #endif
1070 }
1071
1072 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1073 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1074
1075 CodeBlobToOopClosure blobsCl(cl, false);
1076 CLDToOopClosure cldCl(cl, ClassLoaderData::_claim_strong);
1077
1078 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1079 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1080 }
1081
1082 // Returns size in bytes
1083 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1084 if (ShenandoahElasticTLAB) {
1085 // With Elastic TLABs, return the max allowed size, and let the allocation path
1086 // figure out the safe size for current allocation.
1087 return ShenandoahHeapRegion::max_tlab_size_bytes();
1088 } else {
1089 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1090 }
1091 }
1092
1093 size_t ShenandoahHeap::max_tlab_size() const {
1094 // Returns size in words
1095 return ShenandoahHeapRegion::max_tlab_size_words();
1096 }
1097
1098 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1099 public:
1100 void do_thread(Thread* thread) {
1101 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1102 gclab->retire();
1103 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1104 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1105 }
1106 }
1107 };
1108
1109 void ShenandoahHeap::retire_and_reset_gclabs() {
1110 ShenandoahRetireAndResetGCLABClosure cl;
1111 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1112 cl.do_thread(t);
1113 }
1114 workers()->threads_do(&cl);
1115 _safepoint_workers->threads_do(&cl);
1116 }
1117
1118 void ShenandoahHeap::collect(GCCause::Cause cause) {
1119 control_thread()->request_gc(cause);
1120 }
1121
1122 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1123 //assert(false, "Shouldn't need to do full collections");
1124 }
1125
1126 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1127 return _shenandoah_policy;
1128 }
1129
1130 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1131 Space* sp = heap_region_containing(addr);
1132 if (sp != NULL) {
1133 return sp->block_start(addr);
1134 }
1135 return NULL;
1136 }
1137
1138 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1139 Space* sp = heap_region_containing(addr);
1140 assert(sp != NULL, "block_size of address outside of heap");
1141 return sp->block_size(addr);
1142 }
1143
1144 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1145 Space* sp = heap_region_containing(addr);
1146 return sp->block_is_obj(addr);
1147 }
1148
1149 jlong ShenandoahHeap::millis_since_last_gc() {
1150 double v = heuristics()->time_since_last_gc() * 1000;
1151 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1152 return (jlong)v;
1153 }
1154
1155 void ShenandoahHeap::prepare_for_verify() {
1156 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1157 make_parsable(false);
1158 }
1159 }
1160
1161 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1162 workers()->print_worker_threads_on(st);
1163 if (ShenandoahStringDedup::is_enabled()) {
1164 ShenandoahStringDedup::print_worker_threads_on(st);
1165 }
1166 }
1167
1168 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1169 workers()->threads_do(tcl);
1170 _safepoint_workers->threads_do(tcl);
1171 if (ShenandoahStringDedup::is_enabled()) {
1172 ShenandoahStringDedup::threads_do(tcl);
1173 }
1174 }
1175
1176 void ShenandoahHeap::print_tracing_info() const {
1177 LogTarget(Info, gc, stats) lt;
1178 if (lt.is_enabled()) {
1179 ResourceMark rm;
1180 LogStream ls(lt);
1181
1182 phase_timings()->print_on(&ls);
1183
1184 ls.cr();
1185 ls.cr();
1186
1187 shenandoah_policy()->print_gc_stats(&ls);
1188
1189 ls.cr();
1190 ls.cr();
1191
1192 if (ShenandoahPacing) {
1193 pacer()->print_on(&ls);
1194 }
1195
1196 ls.cr();
1197 ls.cr();
1198
1199 if (ShenandoahAllocationTrace) {
1200 assert(alloc_tracker() != NULL, "Must be");
1201 alloc_tracker()->print_on(&ls);
1202 } else {
1203 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1204 }
1205 }
1206 }
1207
1208 void ShenandoahHeap::verify(VerifyOption vo) {
1209 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1210 if (ShenandoahVerify) {
1211 verifier()->verify_generic(vo);
1212 } else {
1213 // TODO: Consider allocating verification bitmaps on demand,
1214 // and turn this on unconditionally.
1215 }
1216 }
1217 }
1218 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1219 return _free_set->capacity();
1220 }
1221
1222 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1223 private:
1224 MarkBitMap* _bitmap;
1225 Stack<oop,mtGC>* _oop_stack;
1226
1227 template <class T>
1228 void do_oop_work(T* p) {
1229 T o = RawAccess<>::oop_load(p);
1230 if (!CompressedOops::is_null(o)) {
1231 oop obj = CompressedOops::decode_not_null(o);
1232 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1233 assert(oopDesc::is_oop(obj), "must be a valid oop");
1234 if (!_bitmap->is_marked((HeapWord*) obj)) {
1235 _bitmap->mark((HeapWord*) obj);
1236 _oop_stack->push(obj);
1237 }
1238 }
1239 }
1240 public:
1241 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1242 _bitmap(bitmap), _oop_stack(oop_stack) {}
1243 void do_oop(oop* p) { do_oop_work(p); }
1244 void do_oop(narrowOop* p) { do_oop_work(p); }
1245 };
1246
1247 /*
1248 * This is public API, used in preparation of object_iterate().
1249 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1250 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1251 * control, we call SH::make_tlabs_parsable().
1252 */
1253 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1254 // No-op.
1255 }
1256
1257 /*
1258 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1259 *
1260 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1261 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1262 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1263 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1264 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1265 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1266 * wiped the bitmap in preparation for next marking).
1267 *
1268 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1269 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1270 * is allowed to report dead objects, but is not required to do so.
1271 */
1272 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1273 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1274 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1275 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1276 return;
1277 }
1278
1279 // Reset bitmap
1280 _aux_bit_map.clear();
1281
1282 Stack<oop,mtGC> oop_stack;
1283
1284 // First, we process all GC roots. This populates the work stack with initial objects.
1285 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1286 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1287 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1288 CodeBlobToOopClosure blobs(&oops, false);
1289 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1290
1291 // Work through the oop stack to traverse heap.
1292 while (! oop_stack.is_empty()) {
1293 oop obj = oop_stack.pop();
1294 assert(oopDesc::is_oop(obj), "must be a valid oop");
1295 cl->do_object(obj);
1296 obj->oop_iterate(&oops);
1297 }
1298
1299 assert(oop_stack.is_empty(), "should be empty");
1300
1301 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1302 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1303 }
1304 }
1305
1306 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1307 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1308 object_iterate(cl);
1309 }
1310
1311 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1312 for (size_t i = 0; i < num_regions(); i++) {
1313 ShenandoahHeapRegion* current = get_region(i);
1314 blk->heap_region_do(current);
1315 }
1316 }
1317
1318 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1319 private:
1320 ShenandoahHeap* const _heap;
1321 ShenandoahHeapRegionClosure* const _blk;
1322
1323 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1324 volatile size_t _index;
1325 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1326
1327 public:
1328 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1329 AbstractGangTask("Parallel Region Task"),
1330 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1331
1332 void work(uint worker_id) {
1333 size_t stride = ShenandoahParallelRegionStride;
1334
1335 size_t max = _heap->num_regions();
1336 while (_index < max) {
1337 size_t cur = Atomic::add(stride, &_index) - stride;
1338 size_t start = cur;
1339 size_t end = MIN2(cur + stride, max);
1340 if (start >= max) break;
1341
1342 for (size_t i = cur; i < end; i++) {
1343 ShenandoahHeapRegion* current = _heap->get_region(i);
1344 _blk->heap_region_do(current);
1345 }
1346 }
1347 }
1348 };
1349
1350 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1351 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1352 if (num_regions() > ShenandoahParallelRegionStride) {
1353 ShenandoahParallelHeapRegionTask task(blk);
1354 workers()->run_task(&task);
1355 } else {
1356 heap_region_iterate(blk);
1357 }
1358 }
1359
1360 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1361 private:
1362 ShenandoahMarkingContext* const _ctx;
1363 public:
1364 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1365
1366 void heap_region_do(ShenandoahHeapRegion* r) {
1367 if (r->is_active()) {
1368 r->clear_live_data();
1369 _ctx->capture_top_at_mark_start(r);
1370 } else {
1371 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1372 assert(_ctx->top_at_mark_start(r) == r->top(),
1373 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1374 }
1375 }
1376
1377 bool is_thread_safe() { return true; }
1378 };
1379
1380 void ShenandoahHeap::op_init_mark() {
1381 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1382 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1383
1384 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1385 assert(!marking_context()->is_complete(), "should not be complete");
1386
1387 if (ShenandoahVerify) {
1388 verifier()->verify_before_concmark();
1389 }
1390
1391 if (VerifyBeforeGC) {
1392 Universe::verify();
1393 }
1394
1395 set_concurrent_mark_in_progress(true);
1396 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1397 {
1398 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1399 make_parsable(true);
1400 }
1401
1402 {
1403 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1404 ShenandoahClearLivenessClosure clc;
1405 parallel_heap_region_iterate(&clc);
1406 }
1407
1408 // Make above changes visible to worker threads
1409 OrderAccess::fence();
1410
1411 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1412
1413 if (UseTLAB) {
1414 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1415 resize_tlabs();
1416 }
1417
1418 if (ShenandoahPacing) {
1419 pacer()->setup_for_mark();
1420 }
1421 }
1422
1423 void ShenandoahHeap::op_mark() {
1424 concurrent_mark()->mark_from_roots();
1425 }
1426
1427 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1428 private:
1429 ShenandoahMarkingContext* const _ctx;
1430 public:
1431 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1432
1433 void heap_region_do(ShenandoahHeapRegion* r) {
1434 if (r->is_active()) {
1435 HeapWord *tams = _ctx->top_at_mark_start(r);
1436 HeapWord *top = r->top();
1437 if (top > tams) {
1438 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1439 }
1440 } else {
1441 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1442 assert(_ctx->top_at_mark_start(r) == r->top(),
1443 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1444 }
1445 }
1446
1447 bool is_thread_safe() { return true; }
1448 };
1449
1450 void ShenandoahHeap::op_final_mark() {
1451 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1452
1453 // It is critical that we
1454 // evacuate roots right after finishing marking, so that we don't
1455 // get unmarked objects in the roots.
1456
1457 if (!cancelled_gc()) {
1458 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1459
1460 if (has_forwarded_objects()) {
1461 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1462 }
1463
1464 stop_concurrent_marking();
1465
1466 {
1467 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1468
1469 // All allocations past TAMS are implicitly live, adjust the region data.
1470 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1471 ShenandoahCompleteLivenessClosure cl;
1472 parallel_heap_region_iterate(&cl);
1473 }
1474
1475 {
1476 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1477
1478 make_parsable(true);
1479
1480 trash_cset_regions();
1481
1482 {
1483 ShenandoahHeapLocker locker(lock());
1484 _collection_set->clear();
1485 _free_set->clear();
1486
1487 heuristics()->choose_collection_set(_collection_set);
1488
1489 _free_set->rebuild();
1490 }
1491 }
1492
1493 // If collection set has candidates, start evacuation.
1494 // Otherwise, bypass the rest of the cycle.
1495 if (!collection_set()->is_empty()) {
1496 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1497
1498 if (ShenandoahVerify) {
1499 verifier()->verify_before_evacuation();
1500 }
1501
1502 set_evacuation_in_progress(true);
1503 // From here on, we need to update references.
1504 set_has_forwarded_objects(true);
1505
1506 evacuate_and_update_roots();
1507
1508 if (ShenandoahPacing) {
1509 pacer()->setup_for_evac();
1510 }
1511 } else {
1512 if (ShenandoahVerify) {
1513 verifier()->verify_after_concmark();
1514 }
1515
1516 if (VerifyAfterGC) {
1517 Universe::verify();
1518 }
1519 }
1520
1521 } else {
1522 concurrent_mark()->cancel();
1523 stop_concurrent_marking();
1524
1525 if (process_references()) {
1526 // Abandon reference processing right away: pre-cleaning must have failed.
1527 ReferenceProcessor *rp = ref_processor();
1528 rp->disable_discovery();
1529 rp->abandon_partial_discovery();
1530 rp->verify_no_references_recorded();
1531 }
1532 }
1533 }
1534
1535 void ShenandoahHeap::op_final_evac() {
1536 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1537
1538 set_evacuation_in_progress(false);
1539
1540 retire_and_reset_gclabs();
1541
1542 if (ShenandoahVerify) {
1543 verifier()->verify_after_evacuation();
1544 }
1545
1546 if (VerifyAfterGC) {
1547 Universe::verify();
1548 }
1549 }
1550
1551 void ShenandoahHeap::op_conc_evac() {
1552 ShenandoahEvacuationTask task(this, _collection_set, true);
1553 workers()->run_task(&task);
1554 }
1555
1556 void ShenandoahHeap::op_stw_evac() {
1557 ShenandoahEvacuationTask task(this, _collection_set, false);
1558 workers()->run_task(&task);
1559 }
1560
1561 void ShenandoahHeap::op_updaterefs() {
1562 update_heap_references(true);
1563 }
1564
1565 void ShenandoahHeap::op_cleanup() {
1566 free_set()->recycle_trash();
1567 }
1568
1569 void ShenandoahHeap::op_reset() {
1570 reset_mark_bitmap();
1571 }
1572
1573 void ShenandoahHeap::op_preclean() {
1574 concurrent_mark()->preclean_weak_refs();
1575 }
1576
1577 void ShenandoahHeap::op_init_traversal() {
1578 traversal_gc()->init_traversal_collection();
1579 }
1580
1581 void ShenandoahHeap::op_traversal() {
1582 traversal_gc()->concurrent_traversal_collection();
1583 }
1584
1585 void ShenandoahHeap::op_final_traversal() {
1586 traversal_gc()->final_traversal_collection();
1587 }
1588
1589 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1590 ShenandoahMetricsSnapshot metrics;
1591 metrics.snap_before();
1592
1593 full_gc()->do_it(cause);
1594 if (UseTLAB) {
1595 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1596 resize_all_tlabs();
1597 }
1598
1599 metrics.snap_after();
1600 metrics.print();
1601
1602 if (metrics.is_good_progress("Full GC")) {
1603 _progress_last_gc.set();
1604 } else {
1605 // Nothing to do. Tell the allocation path that we have failed to make
1606 // progress, and it can finally fail.
1607 _progress_last_gc.unset();
1608 }
1609 }
1610
1611 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1612 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1613 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1614 // some phase, we have to upgrade the Degenerate GC to Full GC.
1615
1616 clear_cancelled_gc();
1617
1618 ShenandoahMetricsSnapshot metrics;
1619 metrics.snap_before();
1620
1621 switch (point) {
1622 case _degenerated_traversal:
1623 {
1624 // Drop the collection set. Note: this leaves some already forwarded objects
1625 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1626 // workarounds in ShenandoahTraversalHeuristics.
1627
1628 ShenandoahHeapLocker locker(lock());
1629 collection_set()->clear_current_index();
1630 for (size_t i = 0; i < collection_set()->count(); i++) {
1631 ShenandoahHeapRegion* r = collection_set()->next();
1632 r->make_regular_bypass();
1633 }
1634 collection_set()->clear();
1635 }
1636 op_final_traversal();
1637 op_cleanup();
1638 return;
1639
1640 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1641 // but enters it at different points, depending on which concurrent phase had
1642 // degenerated.
1643
1644 case _degenerated_outside_cycle:
1645 // We have degenerated from outside the cycle, which means something is bad with
1646 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1647 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1648 // we can do the most aggressive degen cycle, which includes processing references and
1649 // class unloading, unless those features are explicitly disabled.
1650 //
1651 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1652 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1653 set_process_references(heuristics()->can_process_references());
1654 set_unload_classes(heuristics()->can_unload_classes());
1655
1656 if (heuristics()->can_do_traversal_gc()) {
1657 // Not possible to degenerate from here, upgrade to Full GC right away.
1658 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1659 op_degenerated_fail();
1660 return;
1661 }
1662
1663 op_reset();
1664
1665 op_init_mark();
1666 if (cancelled_gc()) {
1667 op_degenerated_fail();
1668 return;
1669 }
1670
1671 case _degenerated_mark:
1672 op_final_mark();
1673 if (cancelled_gc()) {
1674 op_degenerated_fail();
1675 return;
1676 }
1677
1678 op_cleanup();
1679
1680 case _degenerated_evac:
1681 // If heuristics thinks we should do the cycle, this flag would be set,
1682 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1683 if (is_evacuation_in_progress()) {
1684
1685 // Degeneration under oom-evac protocol might have left some objects in
1686 // collection set un-evacuated. Restart evacuation from the beginning to
1687 // capture all objects. For all the objects that are already evacuated,
1688 // it would be a simple check, which is supposed to be fast. This is also
1689 // safe to do even without degeneration, as CSet iterator is at beginning
1690 // in preparation for evacuation anyway.
1691 collection_set()->clear_current_index();
1692
1693 op_stw_evac();
1694 if (cancelled_gc()) {
1695 op_degenerated_fail();
1696 return;
1697 }
1698 }
1699
1700 // If heuristics thinks we should do the cycle, this flag would be set,
1701 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1702 if (has_forwarded_objects()) {
1703 op_init_updaterefs();
1704 if (cancelled_gc()) {
1705 op_degenerated_fail();
1706 return;
1707 }
1708 }
1709
1710 case _degenerated_updaterefs:
1711 if (has_forwarded_objects()) {
1712 op_final_updaterefs();
1713 if (cancelled_gc()) {
1714 op_degenerated_fail();
1715 return;
1716 }
1717 }
1718
1719 op_cleanup();
1720 break;
1721
1722 default:
1723 ShouldNotReachHere();
1724 }
1725
1726 if (ShenandoahVerify) {
1727 verifier()->verify_after_degenerated();
1728 }
1729
1730 if (VerifyAfterGC) {
1731 Universe::verify();
1732 }
1733
1734 metrics.snap_after();
1735 metrics.print();
1736
1737 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1738 // because that probably means the heap is overloaded and/or fragmented.
1739 if (!metrics.is_good_progress("Degenerated GC")) {
1740 _progress_last_gc.unset();
1741 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1742 op_degenerated_futile();
1743 } else {
1744 _progress_last_gc.set();
1745 }
1746 }
1747
1748 void ShenandoahHeap::op_degenerated_fail() {
1749 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1750 shenandoah_policy()->record_degenerated_upgrade_to_full();
1751 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1752 }
1753
1754 void ShenandoahHeap::op_degenerated_futile() {
1755 shenandoah_policy()->record_degenerated_upgrade_to_full();
1756 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1757 }
1758
1759 void ShenandoahHeap::stop_concurrent_marking() {
1760 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1761 if (!cancelled_gc()) {
1762 // If we needed to update refs, and concurrent marking has been cancelled,
1763 // we need to finish updating references.
1764 set_has_forwarded_objects(false);
1765 mark_complete_marking_context();
1766 }
1767 set_concurrent_mark_in_progress(false);
1768 }
1769
1770 void ShenandoahHeap::force_satb_flush_all_threads() {
1771 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1772 // No need to flush SATBs
1773 return;
1774 }
1775
1776 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1777 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1778 }
1779 // The threads are not "acquiring" their thread-local data, but it does not
1780 // hurt to "release" the updates here anyway.
1781 OrderAccess::fence();
1782 }
1783
1784 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1785 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1786 ShenandoahThreadLocalData::set_gc_state(t, state);
1787 }
1788 }
1789
1790 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1791 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1792 _gc_state.set_cond(mask, value);
1793 set_gc_state_all_threads(_gc_state.raw_value());
1794 }
1795
1796 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1797 set_gc_state_mask(MARKING, in_progress);
1798 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1799 }
1800
1801 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1802 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1803 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1804 }
1805
1806 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1807 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1808 set_gc_state_mask(EVACUATION, in_progress);
1809 }
1810
1811 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1812 // Initialize Brooks pointer for the next object
1813 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1814 ShenandoahBrooksPointer::initialize(oop(result));
1815 return result;
1816 }
1817
1818 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1819 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1820 }
1821
1822 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1823 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1824 }
1825
1826 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1827 if (CompressedOops::is_null(obj)) {
1828 return false;
1829 }
1830 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1831 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1832 return _mark_context->is_marked(obj);
1833 }
1834
1835 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1836 if (CompressedOops::is_null(obj)) {
1837 return false;
1838 }
1839 shenandoah_assert_not_forwarded(NULL, obj);
1840 return _mark_context->is_marked(obj);
1841 }
1842
1843 void ShenandoahHeap::ref_processing_init() {
1844 assert(_max_workers > 0, "Sanity");
1845
1846 _ref_processor =
1847 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1848 ParallelRefProcEnabled, // MT processing
1849 _max_workers, // Degree of MT processing
1850 true, // MT discovery
1851 _max_workers, // Degree of MT discovery
1852 false, // Reference discovery is not atomic
1853 NULL, // No closure, should be installed before use
1854 true); // Scale worker threads
1855
1856 shenandoah_assert_rp_isalive_not_installed();
1857 }
1858
1859 GCTracer* ShenandoahHeap::tracer() {
1860 return shenandoah_policy()->tracer();
1861 }
1862
1863 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1864 return _free_set->used();
1865 }
1866
1867 bool ShenandoahHeap::try_cancel_gc() {
1868 while (true) {
1869 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1870 if (prev == CANCELLABLE) return true;
1871 else if (prev == CANCELLED) return false;
1872 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1873 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1874 {
1875 // We need to provide a safepoint here, otherwise we might
1876 // spin forever if a SP is pending.
1877 ThreadBlockInVM sp(JavaThread::current());
1878 SpinPause();
1879 }
1880 }
1881 }
1882
1883 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1884 if (try_cancel_gc()) {
1885 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1886 log_info(gc)("%s", msg.buffer());
1887 Events::log(Thread::current(), "%s", msg.buffer());
1888 }
1889 }
1890
1891 uint ShenandoahHeap::max_workers() {
1892 return _max_workers;
1893 }
1894
1895 void ShenandoahHeap::stop() {
1896 // The shutdown sequence should be able to terminate when GC is running.
1897
1898 // Step 0. Notify policy to disable event recording.
1899 _shenandoah_policy->record_shutdown();
1900
1901 // Step 1. Notify control thread that we are in shutdown.
1902 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1903 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1904 control_thread()->prepare_for_graceful_shutdown();
1905
1906 // Step 2. Notify GC workers that we are cancelling GC.
1907 cancel_gc(GCCause::_shenandoah_stop_vm);
1908
1909 // Step 3. Wait until GC worker exits normally.
1910 control_thread()->stop();
1911
1912 // Step 4. Stop String Dedup thread if it is active
1913 if (ShenandoahStringDedup::is_enabled()) {
1914 ShenandoahStringDedup::stop();
1915 }
1916 }
1917
1918 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1919 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1920
1921 ShenandoahGCPhase root_phase(full_gc ?
1922 ShenandoahPhaseTimings::full_gc_purge :
1923 ShenandoahPhaseTimings::purge);
1924
1925 ShenandoahIsAliveSelector alive;
1926 BoolObjectClosure* is_alive = alive.is_alive_closure();
1927
1928 bool purged_class;
1929
1930 // Unload classes and purge SystemDictionary.
1931 {
1932 ShenandoahGCPhase phase(full_gc ?
1933 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1934 ShenandoahPhaseTimings::purge_class_unload);
1935 purged_class = SystemDictionary::do_unloading(gc_timer());
1936 }
1937
1938 {
1939 ShenandoahGCPhase phase(full_gc ?
1940 ShenandoahPhaseTimings::full_gc_purge_par :
1941 ShenandoahPhaseTimings::purge_par);
1942 uint active = _workers->active_workers();
1943 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1944 _workers->run_task(&unlink_task);
1945 }
1946
1947 {
1948 ShenandoahGCPhase phase(full_gc ?
1949 ShenandoahPhaseTimings::full_gc_purge_cldg :
1950 ShenandoahPhaseTimings::purge_cldg);
1951 ClassLoaderDataGraph::purge();
1952 }
1953 }
1954
1955 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1956 set_gc_state_mask(HAS_FORWARDED, cond);
1957 }
1958
1959 void ShenandoahHeap::set_process_references(bool pr) {
1960 _process_references.set_cond(pr);
1961 }
1962
1963 void ShenandoahHeap::set_unload_classes(bool uc) {
1964 _unload_classes.set_cond(uc);
1965 }
1966
1967 bool ShenandoahHeap::process_references() const {
1968 return _process_references.is_set();
1969 }
1970
1971 bool ShenandoahHeap::unload_classes() const {
1972 return _unload_classes.is_set();
1973 }
1974
1975 address ShenandoahHeap::in_cset_fast_test_addr() {
1976 ShenandoahHeap* heap = ShenandoahHeap::heap();
1977 assert(heap->collection_set() != NULL, "Sanity");
1978 return (address) heap->collection_set()->biased_map_address();
1979 }
1980
1981 address ShenandoahHeap::cancelled_gc_addr() {
1982 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1983 }
1984
1985 address ShenandoahHeap::gc_state_addr() {
1986 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1987 }
1988
1989 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1990 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1991 }
1992
1993 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1994 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1995 }
1996
1997 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1998 _degenerated_gc_in_progress.set_cond(in_progress);
1999 }
2000
2001 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2002 _full_gc_in_progress.set_cond(in_progress);
2003 }
2004
2005 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2006 assert (is_full_gc_in_progress(), "should be");
2007 _full_gc_move_in_progress.set_cond(in_progress);
2008 }
2009
2010 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2011 set_gc_state_mask(UPDATEREFS, in_progress);
2012 }
2013
2014 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2015 ShenandoahCodeRoots::add_nmethod(nm);
2016 }
2017
2018 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2019 ShenandoahCodeRoots::remove_nmethod(nm);
2020 }
2021
2022 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2023 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2024 ShenandoahHeapLocker locker(lock());
2025 heap_region_containing(o)->make_pinned();
2026 return o;
2027 }
2028
2029 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2030 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2031 ShenandoahHeapLocker locker(lock());
2032 heap_region_containing(o)->make_unpinned();
2033 }
2034
2035 GCTimer* ShenandoahHeap::gc_timer() const {
2036 return _gc_timer;
2037 }
2038
2039 #ifdef ASSERT
2040 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2041 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2042
2043 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2044 if (UseDynamicNumberOfGCThreads ||
2045 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2046 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2047 } else {
2048 // Use ParallelGCThreads inside safepoints
2049 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2050 }
2051 } else {
2052 if (UseDynamicNumberOfGCThreads ||
2053 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2054 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2055 } else {
2056 // Use ConcGCThreads outside safepoints
2057 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2058 }
2059 }
2060 }
2061 #endif
2062
2063 ShenandoahVerifier* ShenandoahHeap::verifier() {
2064 guarantee(ShenandoahVerify, "Should be enabled");
2065 assert (_verifier != NULL, "sanity");
2066 return _verifier;
2067 }
2068
2069 template<class T>
2070 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2071 private:
2072 T cl;
2073 ShenandoahHeap* _heap;
2074 ShenandoahRegionIterator* _regions;
2075 bool _concurrent;
2076 public:
2077 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2078 AbstractGangTask("Concurrent Update References Task"),
2079 cl(T()),
2080 _heap(ShenandoahHeap::heap()),
2081 _regions(regions),
2082 _concurrent(concurrent) {
2083 }
2084
2085 void work(uint worker_id) {
2086 if (_concurrent) {
2087 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2088 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2089 do_work();
2090 } else {
2091 ShenandoahParallelWorkerSession worker_session(worker_id);
2092 do_work();
2093 }
2094 }
2095
2096 private:
2097 void do_work() {
2098 ShenandoahHeapRegion* r = _regions->next();
2099 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2100 while (r != NULL) {
2101 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2102 assert (top_at_start_ur >= r->bottom(), "sanity");
2103 if (r->is_active() && !r->is_cset()) {
2104 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2105 }
2106 if (ShenandoahPacing) {
2107 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2108 }
2109 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2110 return;
2111 }
2112 r = _regions->next();
2113 }
2114 }
2115 };
2116
2117 void ShenandoahHeap::update_heap_references(bool concurrent) {
2118 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2119 workers()->run_task(&task);
2120 }
2121
2122 void ShenandoahHeap::op_init_updaterefs() {
2123 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2124
2125 set_evacuation_in_progress(false);
2126
2127 retire_and_reset_gclabs();
2128
2129 if (ShenandoahVerify) {
2130 verifier()->verify_before_updaterefs();
2131 }
2132
2133 set_update_refs_in_progress(true);
2134 make_parsable(true);
2135 for (uint i = 0; i < num_regions(); i++) {
2136 ShenandoahHeapRegion* r = get_region(i);
2137 r->set_concurrent_iteration_safe_limit(r->top());
2138 }
2139
2140 // Reset iterator.
2141 _update_refs_iterator.reset();
2142
2143 if (ShenandoahPacing) {
2144 pacer()->setup_for_updaterefs();
2145 }
2146 }
2147
2148 void ShenandoahHeap::op_final_updaterefs() {
2149 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2150
2151 // Check if there is left-over work, and finish it
2152 if (_update_refs_iterator.has_next()) {
2153 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2154
2155 // Finish updating references where we left off.
2156 clear_cancelled_gc();
2157 update_heap_references(false);
2158 }
2159
2160 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2161 // everything. On degenerated paths, cancelled gc would not be set anyway.
2162 if (cancelled_gc()) {
2163 clear_cancelled_gc();
2164 }
2165 assert(!cancelled_gc(), "Should have been done right before");
2166
2167 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2168 ShenandoahPhaseTimings::degen_gc_update_roots:
2169 ShenandoahPhaseTimings::final_update_refs_roots);
2170
2171 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2172
2173 trash_cset_regions();
2174 set_has_forwarded_objects(false);
2175 set_update_refs_in_progress(false);
2176
2177 if (ShenandoahVerify) {
2178 verifier()->verify_after_updaterefs();
2179 }
2180
2181 if (VerifyAfterGC) {
2182 Universe::verify();
2183 }
2184
2185 {
2186 ShenandoahHeapLocker locker(lock());
2187 _free_set->rebuild();
2188 }
2189 }
2190
2191 #ifdef ASSERT
2192 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2193 _lock.assert_owned_by_current_thread();
2194 }
2195
2196 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2197 _lock.assert_not_owned_by_current_thread();
2198 }
2199
2200 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2201 _lock.assert_owned_by_current_thread_or_safepoint();
2202 }
2203 #endif
2204
2205 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2206 print_on(st);
2207 print_heap_regions_on(st);
2208 }
2209
2210 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2211 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2212
2213 size_t regions_from = _bitmap_regions_per_slice * slice;
2214 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2215 for (size_t g = regions_from; g < regions_to; g++) {
2216 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2217 if (skip_self && g == r->region_number()) continue;
2218 if (get_region(g)->is_committed()) {
2219 return true;
2220 }
2221 }
2222 return false;
2223 }
2224
2225 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2226 assert_heaplock_owned_by_current_thread();
2227
2228 if (is_bitmap_slice_committed(r, true)) {
2229 // Some other region from the group is already committed, meaning the bitmap
2230 // slice is already committed, we exit right away.
2231 return true;
2232 }
2233
2234 // Commit the bitmap slice:
2235 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2236 size_t off = _bitmap_bytes_per_slice * slice;
2237 size_t len = _bitmap_bytes_per_slice;
2238 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2239 return false;
2240 }
2241 return true;
2242 }
2243
2244 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2245 assert_heaplock_owned_by_current_thread();
2246
2247 if (is_bitmap_slice_committed(r, true)) {
2248 // Some other region from the group is still committed, meaning the bitmap
2249 // slice is should stay committed, exit right away.
2250 return true;
2251 }
2252
2253 // Uncommit the bitmap slice:
2254 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2255 size_t off = _bitmap_bytes_per_slice * slice;
2256 size_t len = _bitmap_bytes_per_slice;
2257 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2258 return false;
2259 }
2260 return true;
2261 }
2262
2263 void ShenandoahHeap::safepoint_synchronize_begin() {
2264 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2265 SuspendibleThreadSet::synchronize();
2266 }
2267 }
2268
2269 void ShenandoahHeap::safepoint_synchronize_end() {
2270 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2271 SuspendibleThreadSet::desynchronize();
2272 }
2273 }
2274
2275 void ShenandoahHeap::vmop_entry_init_mark() {
2276 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2277 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2278 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2279
2280 try_inject_alloc_failure();
2281 VM_ShenandoahInitMark op;
2282 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2283 }
2284
2285 void ShenandoahHeap::vmop_entry_final_mark() {
2286 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2287 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2288 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2289
2290 try_inject_alloc_failure();
2291 VM_ShenandoahFinalMarkStartEvac op;
2292 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2293 }
2294
2295 void ShenandoahHeap::vmop_entry_final_evac() {
2296 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2297 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2298 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2299
2300 VM_ShenandoahFinalEvac op;
2301 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2302 }
2303
2304 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2305 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2306 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2307 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2308
2309 try_inject_alloc_failure();
2310 VM_ShenandoahInitUpdateRefs op;
2311 VMThread::execute(&op);
2312 }
2313
2314 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2315 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2316 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2317 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2318
2319 try_inject_alloc_failure();
2320 VM_ShenandoahFinalUpdateRefs op;
2321 VMThread::execute(&op);
2322 }
2323
2324 void ShenandoahHeap::vmop_entry_init_traversal() {
2325 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2326 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2327 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2328
2329 try_inject_alloc_failure();
2330 VM_ShenandoahInitTraversalGC op;
2331 VMThread::execute(&op);
2332 }
2333
2334 void ShenandoahHeap::vmop_entry_final_traversal() {
2335 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2336 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2337 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2338
2339 try_inject_alloc_failure();
2340 VM_ShenandoahFinalTraversalGC op;
2341 VMThread::execute(&op);
2342 }
2343
2344 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2345 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2346 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2347 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2348
2349 try_inject_alloc_failure();
2350 VM_ShenandoahFullGC op(cause);
2351 VMThread::execute(&op);
2352 }
2353
2354 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2355 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2356 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2357 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2358
2359 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2360 VMThread::execute(°enerated_gc);
2361 }
2362
2363 void ShenandoahHeap::entry_init_mark() {
2364 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2365 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2366 const char* msg = init_mark_event_message();
2367 GCTraceTime(Info, gc) time(msg, gc_timer());
2368 EventMark em("%s", msg);
2369
2370 ShenandoahWorkerScope scope(workers(),
2371 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2372 "init marking");
2373
2374 op_init_mark();
2375 }
2376
2377 void ShenandoahHeap::entry_final_mark() {
2378 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2379 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2380 const char* msg = final_mark_event_message();
2381 GCTraceTime(Info, gc) time(msg, gc_timer());
2382 EventMark em("%s", msg);
2383
2384 ShenandoahWorkerScope scope(workers(),
2385 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2386 "final marking");
2387
2388 op_final_mark();
2389 }
2390
2391 void ShenandoahHeap::entry_final_evac() {
2392 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2393 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2394 static const char* msg = "Pause Final Evac";
2395 GCTraceTime(Info, gc) time(msg, gc_timer());
2396 EventMark em("%s", msg);
2397
2398 op_final_evac();
2399 }
2400
2401 void ShenandoahHeap::entry_init_updaterefs() {
2402 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2403 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2404
2405 static const char* msg = "Pause Init Update Refs";
2406 GCTraceTime(Info, gc) time(msg, gc_timer());
2407 EventMark em("%s", msg);
2408
2409 // No workers used in this phase, no setup required
2410
2411 op_init_updaterefs();
2412 }
2413
2414 void ShenandoahHeap::entry_final_updaterefs() {
2415 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2416 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2417
2418 static const char* msg = "Pause Final Update Refs";
2419 GCTraceTime(Info, gc) time(msg, gc_timer());
2420 EventMark em("%s", msg);
2421
2422 ShenandoahWorkerScope scope(workers(),
2423 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2424 "final reference update");
2425
2426 op_final_updaterefs();
2427 }
2428
2429 void ShenandoahHeap::entry_init_traversal() {
2430 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2431 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2432
2433 static const char* msg = "Pause Init Traversal";
2434 GCTraceTime(Info, gc) time(msg, gc_timer());
2435 EventMark em("%s", msg);
2436
2437 ShenandoahWorkerScope scope(workers(),
2438 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2439 "init traversal");
2440
2441 op_init_traversal();
2442 }
2443
2444 void ShenandoahHeap::entry_final_traversal() {
2445 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2446 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2447
2448 static const char* msg = "Pause Final Traversal";
2449 GCTraceTime(Info, gc) time(msg, gc_timer());
2450 EventMark em("%s", msg);
2451
2452 ShenandoahWorkerScope scope(workers(),
2453 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2454 "final traversal");
2455
2456 op_final_traversal();
2457 }
2458
2459 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2460 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2461 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2462
2463 static const char* msg = "Pause Full";
2464 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2465 EventMark em("%s", msg);
2466
2467 ShenandoahWorkerScope scope(workers(),
2468 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2469 "full gc");
2470
2471 op_full(cause);
2472 }
2473
2474 void ShenandoahHeap::entry_degenerated(int point) {
2475 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2476 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2477
2478 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2479 const char* msg = degen_event_message(dpoint);
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_stw_degenerated(),
2485 "stw degenerated gc");
2486
2487 set_degenerated_gc_in_progress(true);
2488 op_degenerated(dpoint);
2489 set_degenerated_gc_in_progress(false);
2490 }
2491
2492 void ShenandoahHeap::entry_mark() {
2493 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2494
2495 const char* msg = conc_mark_event_message();
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_marking(),
2501 "concurrent marking");
2502
2503 try_inject_alloc_failure();
2504 op_mark();
2505 }
2506
2507 void ShenandoahHeap::entry_evac() {
2508 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2509 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2510
2511 static const char* msg = "Concurrent evacuation";
2512 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2513 EventMark em("%s", msg);
2514
2515 ShenandoahWorkerScope scope(workers(),
2516 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2517 "concurrent evacuation");
2518
2519 try_inject_alloc_failure();
2520 op_conc_evac();
2521 }
2522
2523 void ShenandoahHeap::entry_updaterefs() {
2524 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2525
2526 static const char* msg = "Concurrent update references";
2527 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2528 EventMark em("%s", msg);
2529
2530 ShenandoahWorkerScope scope(workers(),
2531 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2532 "concurrent reference update");
2533
2534 try_inject_alloc_failure();
2535 op_updaterefs();
2536 }
2537 void ShenandoahHeap::entry_cleanup() {
2538 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2539
2540 static const char* msg = "Concurrent cleanup";
2541 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2542 EventMark em("%s", msg);
2543
2544 // This phase does not use workers, no need for setup
2545
2546 try_inject_alloc_failure();
2547 op_cleanup();
2548 }
2549
2550 void ShenandoahHeap::entry_reset() {
2551 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2552
2553 static const char* msg = "Concurrent reset";
2554 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2555 EventMark em("%s", msg);
2556
2557 ShenandoahWorkerScope scope(workers(),
2558 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2559 "concurrent reset");
2560
2561 try_inject_alloc_failure();
2562 op_reset();
2563 }
2564
2565 void ShenandoahHeap::entry_preclean() {
2566 if (ShenandoahPreclean && process_references()) {
2567 static const char* msg = "Concurrent precleaning";
2568 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2569 EventMark em("%s", msg);
2570
2571 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2572
2573 ShenandoahWorkerScope scope(workers(),
2574 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2575 "concurrent preclean",
2576 /* check_workers = */ false);
2577
2578 try_inject_alloc_failure();
2579 op_preclean();
2580 }
2581 }
2582
2583 void ShenandoahHeap::entry_traversal() {
2584 static const char* msg = "Concurrent traversal";
2585 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2586 EventMark em("%s", msg);
2587
2588 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2589
2590 ShenandoahWorkerScope scope(workers(),
2591 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2592 "concurrent traversal");
2593
2594 try_inject_alloc_failure();
2595 op_traversal();
2596 }
2597
2598 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2599 static const char *msg = "Concurrent uncommit";
2600 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2601 EventMark em("%s", msg);
2602
2603 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2604
2605 op_uncommit(shrink_before);
2606 }
2607
2608 void ShenandoahHeap::try_inject_alloc_failure() {
2609 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2610 _inject_alloc_failure.set();
2611 os::naked_short_sleep(1);
2612 if (cancelled_gc()) {
2613 log_info(gc)("Allocation failure was successfully injected");
2614 }
2615 }
2616 }
2617
2618 bool ShenandoahHeap::should_inject_alloc_failure() {
2619 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2620 }
2621
2622 void ShenandoahHeap::initialize_serviceability() {
2623 _memory_pool = new ShenandoahMemoryPool(this);
2624 _cycle_memory_manager.add_pool(_memory_pool);
2625 _stw_memory_manager.add_pool(_memory_pool);
2626 }
2627
2628 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2629 GrowableArray<GCMemoryManager*> memory_managers(2);
2630 memory_managers.append(&_cycle_memory_manager);
2631 memory_managers.append(&_stw_memory_manager);
2632 return memory_managers;
2633 }
2634
2635 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2636 GrowableArray<MemoryPool*> memory_pools(1);
2637 memory_pools.append(_memory_pool);
2638 return memory_pools;
2639 }
2640
2641 void ShenandoahHeap::enter_evacuation() {
2642 _oom_evac_handler.enter_evacuation();
2643 }
2644
2645 void ShenandoahHeap::leave_evacuation() {
2646 _oom_evac_handler.leave_evacuation();
2647 }
2648
2649 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2650 _heap(ShenandoahHeap::heap()),
2651 _index(0) {}
2652
2653 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2654 _heap(heap),
2655 _index(0) {}
2656
2657 void ShenandoahRegionIterator::reset() {
2658 _index = 0;
2659 }
2660
2661 bool ShenandoahRegionIterator::has_next() const {
2662 return _index < _heap->num_regions();
2663 }
2664
2665 char ShenandoahHeap::gc_state() const {
2666 return _gc_state.raw_value();
2667 }
2668
2669 void ShenandoahHeap::deduplicate_string(oop str) {
2670 assert(java_lang_String::is_instance(str), "invariant");
2671
2672 if (ShenandoahStringDedup::is_enabled()) {
2673 ShenandoahStringDedup::deduplicate(str);
2674 }
2675 }
2676
2677 const char* ShenandoahHeap::init_mark_event_message() const {
2678 bool update_refs = has_forwarded_objects();
2679 bool proc_refs = process_references();
2680 bool unload_cls = unload_classes();
2681
2682 if (update_refs && proc_refs && unload_cls) {
2683 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2684 } else if (update_refs && proc_refs) {
2685 return "Pause Init Mark (update refs) (process weakrefs)";
2686 } else if (update_refs && unload_cls) {
2687 return "Pause Init Mark (update refs) (unload classes)";
2688 } else if (proc_refs && unload_cls) {
2689 return "Pause Init Mark (process weakrefs) (unload classes)";
2690 } else if (update_refs) {
2691 return "Pause Init Mark (update refs)";
2692 } else if (proc_refs) {
2693 return "Pause Init Mark (process weakrefs)";
2694 } else if (unload_cls) {
2695 return "Pause Init Mark (unload classes)";
2696 } else {
2697 return "Pause Init Mark";
2698 }
2699 }
2700
2701 const char* ShenandoahHeap::final_mark_event_message() const {
2702 bool update_refs = has_forwarded_objects();
2703 bool proc_refs = process_references();
2704 bool unload_cls = unload_classes();
2705
2706 if (update_refs && proc_refs && unload_cls) {
2707 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2708 } else if (update_refs && proc_refs) {
2709 return "Pause Final Mark (update refs) (process weakrefs)";
2710 } else if (update_refs && unload_cls) {
2711 return "Pause Final Mark (update refs) (unload classes)";
2712 } else if (proc_refs && unload_cls) {
2713 return "Pause Final Mark (process weakrefs) (unload classes)";
2714 } else if (update_refs) {
2715 return "Pause Final Mark (update refs)";
2716 } else if (proc_refs) {
2717 return "Pause Final Mark (process weakrefs)";
2718 } else if (unload_cls) {
2719 return "Pause Final Mark (unload classes)";
2720 } else {
2721 return "Pause Final Mark";
2722 }
2723 }
2724
2725 const char* ShenandoahHeap::conc_mark_event_message() const {
2726 bool update_refs = has_forwarded_objects();
2727 bool proc_refs = process_references();
2728 bool unload_cls = unload_classes();
2729
2730 if (update_refs && proc_refs && unload_cls) {
2731 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2732 } else if (update_refs && proc_refs) {
2733 return "Concurrent marking (update refs) (process weakrefs)";
2734 } else if (update_refs && unload_cls) {
2735 return "Concurrent marking (update refs) (unload classes)";
2736 } else if (proc_refs && unload_cls) {
2737 return "Concurrent marking (process weakrefs) (unload classes)";
2738 } else if (update_refs) {
2739 return "Concurrent marking (update refs)";
2740 } else if (proc_refs) {
2741 return "Concurrent marking (process weakrefs)";
2742 } else if (unload_cls) {
2743 return "Concurrent marking (unload classes)";
2744 } else {
2745 return "Concurrent marking";
2746 }
2747 }
2748
2749 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2750 switch (point) {
2751 case _degenerated_unset:
2752 return "Pause Degenerated GC (<UNSET>)";
2753 case _degenerated_traversal:
2754 return "Pause Degenerated GC (Traversal)";
2755 case _degenerated_outside_cycle:
2756 return "Pause Degenerated GC (Outside of Cycle)";
2757 case _degenerated_mark:
2758 return "Pause Degenerated GC (Mark)";
2759 case _degenerated_evac:
2760 return "Pause Degenerated GC (Evacuation)";
2761 case _degenerated_updaterefs:
2762 return "Pause Degenerated GC (Update Refs)";
2763 default:
2764 ShouldNotReachHere();
2765 return "ERROR";
2766 }
2767 }
2768
2769 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2770 #ifdef ASSERT
2771 assert(worker_id < _max_workers, "sanity");
2772 for (uint i = 0; i < num_regions(); i++) {
2773 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2774 }
2775 #endif
2776 return _liveness_cache[worker_id];
2777 }
2778
2779 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2780 assert(worker_id < _max_workers, "sanity");
2781 jushort* ld = _liveness_cache[worker_id];
2782 for (uint i = 0; i < num_regions(); i++) {
2783 ShenandoahHeapRegion* r = get_region(i);
2784 jushort live = ld[i];
2785 if (live > 0) {
2786 r->increase_live_data_gc_words(live);
2787 ld[i] = 0;
2788 }
2789 }
2790 }
2791
2792 size_t ShenandoahHeap::obj_size(oop obj) const {
2793 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2794 }
2795
2796 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2797 return ShenandoahBrooksPointer::byte_size();
2798 }
2799
2800 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2801 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2802 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2803 }