1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/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.hpp"
39 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
40 #include "gc/shenandoah/shenandoahControlThread.hpp"
41 #include "gc/shenandoah/shenandoahFreeSet.hpp"
42 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
43 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
45 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
46 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
47 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
48 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
49 #include "gc/shenandoah/shenandoahMetrics.hpp"
50 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
51 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
52 #include "gc/shenandoah/shenandoahPacer.hpp"
53 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
54 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
55 #include "gc/shenandoah/shenandoahStringDedup.hpp"
56 #include "gc/shenandoah/shenandoahUtils.hpp"
57 #include "gc/shenandoah/shenandoahVerifier.hpp"
58 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
59 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
60 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
61 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
67 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
68
69 #include "memory/metaspace.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 ShenandoahBarrierSet::satb_mark_queue_set().set_buffer_size(ShenandoahSATBBufferSize);
180
181 // The call below uses stuff (the SATB* things) that are in G1, but probably
182 // belong into a shared location.
183 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
184 SATB_Q_CBL_mon,
185 SATB_Q_FL_lock,
186 20 /*G1SATBProcessCompletedThreshold */,
187 60 /* G1SATBBufferEnqueueingThresholdPercent */,
188 Shared_SATB_Q_lock);
189
190 // Reserve space for prev and next bitmap.
191 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
192 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
193 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
194 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
195
196 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
197
198 guarantee(bitmap_bytes_per_region != 0,
199 "Bitmap bytes per region should not be zero");
200 guarantee(is_power_of_2(bitmap_bytes_per_region),
201 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
202
203 if (bitmap_page_size > bitmap_bytes_per_region) {
204 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
205 _bitmap_bytes_per_slice = bitmap_page_size;
206 } else {
207 _bitmap_regions_per_slice = 1;
208 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
209 }
210
211 guarantee(_bitmap_regions_per_slice >= 1,
212 "Should have at least one region per slice: " SIZE_FORMAT,
213 _bitmap_regions_per_slice);
214
215 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
216 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
217 _bitmap_bytes_per_slice, bitmap_page_size);
218
219 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
220 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
221 _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
222
223 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
224 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
225 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
226 os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
227 "couldn't allocate initial bitmap");
228
229 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
230
231 if (ShenandoahVerify) {
232 ReservedSpace verify_bitmap(_bitmap_size, page_size);
233 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
234 "couldn't allocate verification bitmap");
235 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
236 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
237 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
238 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
239 }
240
241 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
242
243 {
244 ShenandoahHeapLocker locker(lock());
245 for (size_t i = 0; i < _num_regions; i++) {
246 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
247 (HeapWord*) pgc_rs.base() + reg_size_words * i,
248 reg_size_words,
249 i,
250 i < num_committed_regions);
251
252 _marking_context->initialize_top_at_mark_start(r);
253 _regions[i] = r;
254 assert(!collection_set()->is_in(i), "New region should not be in collection set");
255 }
256
257 // Initialize to complete
258 _marking_context->mark_complete();
259
260 _free_set->rebuild();
261 }
262
263 if (ShenandoahAlwaysPreTouch) {
264 assert (!AlwaysPreTouch, "Should have been overridden");
265
266 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
267 // before initialize() below zeroes it with initializing thread. For any given region,
268 // we touch the region and the corresponding bitmaps from the same thread.
269 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
270
271 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
272 _num_regions, page_size);
273 ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
274 _workers->run_task(&cl);
275 }
276
277 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
278 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
279 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
280 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
281 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
282
283 _traversal_gc = heuristics()->can_do_traversal_gc() ?
284 new ShenandoahTraversalGC(this, _num_regions) :
285 NULL;
286
287 _monitoring_support = new ShenandoahMonitoringSupport(this);
288
289 _phase_timings = new ShenandoahPhaseTimings();
290
291 if (ShenandoahAllocationTrace) {
292 _alloc_tracker = new ShenandoahAllocTracker();
293 }
294
295 ShenandoahStringDedup::initialize();
296
297 _control_thread = new ShenandoahControlThread();
298
299 ShenandoahCodeRoots::initialize();
300
301 log_info(gc, init)("Safepointing mechanism: %s",
302 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
303 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
304
305 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
306 for (uint worker = 0; worker < _max_workers; worker++) {
307 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
308 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
309 }
310
311 return JNI_OK;
312 }
313
314 void ShenandoahHeap::initialize_heuristics() {
315 if (ShenandoahGCHeuristics != NULL) {
316 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
317 _heuristics = new ShenandoahAggressiveHeuristics();
318 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
319 _heuristics = new ShenandoahStaticHeuristics();
320 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
321 _heuristics = new ShenandoahAdaptiveHeuristics();
322 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
323 _heuristics = new ShenandoahPassiveHeuristics();
324 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
325 _heuristics = new ShenandoahCompactHeuristics();
326 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
327 _heuristics = new ShenandoahTraversalHeuristics();
328 } else {
329 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
330 }
331
332 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
333 vm_exit_during_initialization(
334 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
335 _heuristics->name()));
336 }
337 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
338 vm_exit_during_initialization(
339 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
340 _heuristics->name()));
341 }
342
343 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
344 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
345 }
346 log_info(gc, init)("Shenandoah heuristics: %s",
347 _heuristics->name());
348 } else {
349 ShouldNotReachHere();
350 }
351
352 }
353
354 #ifdef _MSC_VER
355 #pragma warning( push )
356 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
357 #endif
358
359 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
360 CollectedHeap(),
361 _initial_size(0),
362 _used(0),
363 _committed(0),
364 _bytes_allocated_since_gc_start(0),
365 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
366 _workers(NULL),
367 _safepoint_workers(NULL),
368 _num_regions(0),
369 _regions(NULL),
370 _update_refs_iterator(this),
371 _control_thread(NULL),
372 _shenandoah_policy(policy),
373 _heuristics(NULL),
374 _free_set(NULL),
375 _scm(new ShenandoahConcurrentMark()),
376 _traversal_gc(NULL),
377 _full_gc(new ShenandoahMarkCompact()),
378 _pacer(NULL),
379 _verifier(NULL),
380 _alloc_tracker(NULL),
381 _phase_timings(NULL),
382 _monitoring_support(NULL),
383 _memory_pool(NULL),
384 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
385 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
386 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
387 _soft_ref_policy(),
388 _ref_processor(NULL),
389 _marking_context(NULL),
390 _collection_set(NULL)
391 {
392 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
393 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
394
395 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
396
397 _max_workers = MAX2(_max_workers, 1U);
398 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
399 /* are_GC_task_threads */true,
400 /* are_ConcurrentGC_threads */false);
401 if (_workers == NULL) {
402 vm_exit_during_initialization("Failed necessary allocation.");
403 } else {
404 _workers->initialize_workers();
405 }
406
407 if (ParallelSafepointCleanupThreads > 1) {
408 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
409 ParallelSafepointCleanupThreads,
410 false, false);
411 _safepoint_workers->initialize_workers();
412 }
413 }
414
415 #ifdef _MSC_VER
416 #pragma warning( pop )
417 #endif
418
419 class ShenandoahResetBitmapTask : public AbstractGangTask {
420 private:
421 ShenandoahRegionIterator _regions;
422
423 public:
424 ShenandoahResetBitmapTask() :
425 AbstractGangTask("Parallel Reset Bitmap Task") {}
426
427 void work(uint worker_id) {
428 ShenandoahHeapRegion* region = _regions.next();
429 ShenandoahHeap* heap = ShenandoahHeap::heap();
430 ShenandoahMarkingContext* const ctx = heap->marking_context();
431 while (region != NULL) {
432 if (heap->is_bitmap_slice_committed(region)) {
433 ctx->clear_bitmap(region);
434 }
435 region = _regions.next();
436 }
437 }
438 };
439
440 void ShenandoahHeap::reset_mark_bitmap() {
441 assert_gc_workers(_workers->active_workers());
442 mark_incomplete_marking_context();
443
444 ShenandoahResetBitmapTask task;
445 _workers->run_task(&task);
446 }
447
448 void ShenandoahHeap::print_on(outputStream* st) const {
449 st->print_cr("Shenandoah Heap");
450 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
451 capacity() / K, committed() / K, used() / K);
452 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
453 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
454
455 st->print("Status: ");
456 if (has_forwarded_objects()) st->print("has forwarded objects, ");
457 if (is_concurrent_mark_in_progress()) st->print("marking, ");
458 if (is_evacuation_in_progress()) st->print("evacuating, ");
459 if (is_update_refs_in_progress()) st->print("updating refs, ");
460 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
461 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
462 if (is_full_gc_in_progress()) st->print("full gc, ");
463 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
464
465 if (cancelled_gc()) {
466 st->print("cancelled");
467 } else {
468 st->print("not cancelled");
469 }
470 st->cr();
471
472 st->print_cr("Reserved region:");
473 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
474 p2i(reserved_region().start()),
475 p2i(reserved_region().end()));
476
477 st->cr();
478 MetaspaceUtils::print_on(st);
479
480 if (Verbose) {
481 print_heap_regions_on(st);
482 }
483 }
484
485 class ShenandoahInitGCLABClosure : public ThreadClosure {
486 public:
487 void do_thread(Thread* thread) {
488 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
489 ShenandoahThreadLocalData::initialize_gclab(thread);
490 }
491 }
492 };
493
494 void ShenandoahHeap::post_initialize() {
495 CollectedHeap::post_initialize();
496 MutexLocker ml(Threads_lock);
497
498 ShenandoahInitGCLABClosure init_gclabs;
499 Threads::threads_do(&init_gclabs);
500 _workers->threads_do(&init_gclabs);
501 _safepoint_workers->threads_do(&init_gclabs);
502
503 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
504 // Now, we will let WorkGang to initialize gclab when new worker is created.
505 _workers->set_initialize_gclab();
506
507 _scm->initialize(_max_workers);
508 _full_gc->initialize(_gc_timer);
509
510 ref_processing_init();
511
512 _heuristics->initialize();
513 }
514
515 size_t ShenandoahHeap::used() const {
516 return OrderAccess::load_acquire(&_used);
517 }
518
519 size_t ShenandoahHeap::committed() const {
520 OrderAccess::acquire();
521 return _committed;
522 }
523
524 void ShenandoahHeap::increase_committed(size_t bytes) {
525 assert_heaplock_or_safepoint();
526 _committed += bytes;
527 }
528
529 void ShenandoahHeap::decrease_committed(size_t bytes) {
530 assert_heaplock_or_safepoint();
531 _committed -= bytes;
532 }
533
534 void ShenandoahHeap::increase_used(size_t bytes) {
535 Atomic::add(bytes, &_used);
536 }
537
538 void ShenandoahHeap::set_used(size_t bytes) {
539 OrderAccess::release_store_fence(&_used, bytes);
540 }
541
542 void ShenandoahHeap::decrease_used(size_t bytes) {
543 assert(used() >= bytes, "never decrease heap size by more than we've left");
544 Atomic::sub(bytes, &_used);
545 }
546
547 void ShenandoahHeap::increase_allocated(size_t bytes) {
548 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
549 }
550
551 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
552 size_t bytes = words * HeapWordSize;
553 if (!waste) {
554 increase_used(bytes);
555 }
556 increase_allocated(bytes);
557 if (ShenandoahPacing) {
558 control_thread()->pacing_notify_alloc(words);
559 if (waste) {
560 pacer()->claim_for_alloc(words, true);
561 }
562 }
563 }
564
565 size_t ShenandoahHeap::capacity() const {
566 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
567 }
568
569 size_t ShenandoahHeap::max_capacity() const {
570 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
571 }
572
573 size_t ShenandoahHeap::initial_capacity() const {
574 return _initial_size;
575 }
576
577 bool ShenandoahHeap::is_in(const void* p) const {
578 HeapWord* heap_base = (HeapWord*) base();
579 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
580 return p >= heap_base && p < last_region_end;
581 }
582
583 void ShenandoahHeap::op_uncommit(double shrink_before) {
584 assert (ShenandoahUncommit, "should be enabled");
585
586 size_t count = 0;
587 for (size_t i = 0; i < num_regions(); i++) {
588 ShenandoahHeapRegion* r = get_region(i);
589 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
590 ShenandoahHeapLocker locker(lock());
591 if (r->is_empty_committed()) {
592 r->make_uncommitted();
593 count++;
594 }
595 }
596 SpinPause(); // allow allocators to take the lock
597 }
598
599 if (count > 0) {
600 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
601 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
602 control_thread()->notify_heap_changed();
603 }
604 }
605
606 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
607 // New object should fit the GCLAB size
608 size_t min_size = MAX2(size, PLAB::min_size());
609
610 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
611 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
612 new_size = MIN2(new_size, PLAB::max_size());
613 new_size = MAX2(new_size, PLAB::min_size());
614
615 // Record new heuristic value even if we take any shortcut. This captures
616 // the case when moderately-sized objects always take a shortcut. At some point,
617 // heuristics should catch up with them.
618 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
619
620 if (new_size < size) {
621 // New size still does not fit the object. Fall back to shared allocation.
622 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
623 return NULL;
624 }
625
626 // Retire current GCLAB, and allocate a new one.
627 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
628 gclab->retire();
629
630 size_t actual_size = 0;
631 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
632 if (gclab_buf == NULL) {
633 return NULL;
634 }
635
636 assert (size <= actual_size, "allocation should fit");
637
638 if (ZeroTLAB) {
639 // ..and clear it.
640 Copy::zero_to_words(gclab_buf, actual_size);
641 } else {
642 // ...and zap just allocated object.
643 #ifdef ASSERT
644 // Skip mangling the space corresponding to the object header to
645 // ensure that the returned space is not considered parsable by
646 // any concurrent GC thread.
647 size_t hdr_size = oopDesc::header_size();
648 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
649 #endif // ASSERT
650 }
651 gclab->set_buf(gclab_buf, actual_size);
652 return gclab->allocate(size);
653 }
654
655 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
656 size_t requested_size,
657 size_t* actual_size) {
658 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
659 HeapWord* res = allocate_memory(req);
660 if (res != NULL) {
661 *actual_size = req.actual_size();
662 } else {
663 *actual_size = 0;
664 }
665 return res;
666 }
667
668 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
669 size_t word_size,
670 size_t* actual_size) {
671 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
672 HeapWord* res = allocate_memory(req);
673 if (res != NULL) {
674 *actual_size = req.actual_size();
675 } else {
676 *actual_size = 0;
677 }
678 return res;
679 }
680
681 ShenandoahHeap* ShenandoahHeap::heap() {
682 CollectedHeap* heap = Universe::heap();
683 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
684 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
685 return (ShenandoahHeap*) heap;
686 }
687
688 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
689 CollectedHeap* heap = Universe::heap();
690 return (ShenandoahHeap*) heap;
691 }
692
693 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
694 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
695
696 intptr_t pacer_epoch = 0;
697 bool in_new_region = false;
698 HeapWord* result = NULL;
699
700 if (req.is_mutator_alloc()) {
701 if (ShenandoahPacing) {
702 pacer()->pace_for_alloc(req.size());
703 pacer_epoch = pacer()->epoch();
704 }
705
706 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
707 result = allocate_memory_under_lock(req, in_new_region);
708 }
709
710 // Allocation failed, block until control thread reacted, then retry allocation.
711 //
712 // It might happen that one of the threads requesting allocation would unblock
713 // way later after GC happened, only to fail the second allocation, because
714 // other threads have already depleted the free storage. In this case, a better
715 // strategy is to try again, as long as GC makes progress.
716 //
717 // Then, we need to make sure the allocation was retried after at least one
718 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
719
720 size_t tries = 0;
721
722 while (result == NULL && _progress_last_gc.is_set()) {
723 tries++;
724 control_thread()->handle_alloc_failure(req.size());
725 result = allocate_memory_under_lock(req, in_new_region);
726 }
727
728 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
729 tries++;
730 control_thread()->handle_alloc_failure(req.size());
731 result = allocate_memory_under_lock(req, in_new_region);
732 }
733
734 } else {
735 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
736 result = allocate_memory_under_lock(req, in_new_region);
737 // Do not call handle_alloc_failure() here, because we cannot block.
738 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
739 }
740
741 if (in_new_region) {
742 control_thread()->notify_heap_changed();
743 }
744
745 if (result != NULL) {
746 size_t requested = req.size();
747 size_t actual = req.actual_size();
748
749 assert (req.is_lab_alloc() || (requested == actual),
750 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
751 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
752
753 if (req.is_mutator_alloc()) {
754 notify_mutator_alloc_words(actual, false);
755
756 // If we requested more than we were granted, give the rest back to pacer.
757 // This only matters if we are in the same pacing epoch: do not try to unpace
758 // over the budget for the other phase.
759 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
760 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
761 }
762 } else {
763 increase_used(actual*HeapWordSize);
764 }
765 }
766
767 return result;
768 }
769
770 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
771 ShenandoahHeapLocker locker(lock());
772 return _free_set->allocate(req, in_new_region);
773 }
774
775 class ShenandoahMemAllocator : public MemAllocator {
776 private:
777 MemAllocator& _initializer;
778 public:
779 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
780 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
781 _initializer(initializer) {}
782
783 protected:
784 virtual HeapWord* mem_allocate(Allocation& allocation) const {
785 HeapWord* result = MemAllocator::mem_allocate(allocation);
786 // Initialize brooks-pointer
787 if (result != NULL) {
788 result += ShenandoahBrooksPointer::word_size();
789 ShenandoahBrooksPointer::initialize(oop(result));
790 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
791 }
792 return result;
793 }
794
795 virtual oop initialize(HeapWord* mem) const {
796 return _initializer.initialize(mem);
797 }
798 };
799
800 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
801 ObjAllocator initializer(klass, size, THREAD);
802 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
803 return allocator.allocate();
804 }
805
806 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
807 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
808 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
809 return allocator.allocate();
810 }
811
812 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
813 ClassAllocator initializer(klass, size, THREAD);
814 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
815 return allocator.allocate();
816 }
817
818 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
819 bool* gc_overhead_limit_was_exceeded) {
820 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
821 return allocate_memory(req);
822 }
823
824 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
825 size_t size,
826 Metaspace::MetadataType mdtype) {
827 MetaWord* result;
828
829 // Inform metaspace OOM to GC heuristics if class unloading is possible.
830 if (heuristics()->can_unload_classes()) {
831 ShenandoahHeuristics* h = heuristics();
832 h->record_metaspace_oom();
833 }
834
835 // Expand and retry allocation
836 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
837 if (result != NULL) {
838 return result;
839 }
840
841 // Start full GC
842 collect(GCCause::_metadata_GC_clear_soft_refs);
843
844 // Retry allocation
845 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
846 if (result != NULL) {
847 return result;
848 }
849
850 // Expand and retry allocation
851 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
852 if (result != NULL) {
853 return result;
854 }
855
856 // Out of memory
857 return NULL;
858 }
859
860 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
861 HeapWord* obj = tlab_post_allocation_setup(start);
862 CollectedHeap::fill_with_object(obj, end);
863 }
864
865 size_t ShenandoahHeap::min_dummy_object_size() const {
866 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
867 }
868
869 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
870 private:
871 ShenandoahHeap* _heap;
872 Thread* _thread;
873 public:
874 ShenandoahEvacuateUpdateRootsClosure() :
875 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
876 }
877
878 private:
879 template <class T>
880 void do_oop_work(T* p) {
881 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
882
883 T o = RawAccess<>::oop_load(p);
884 if (! CompressedOops::is_null(o)) {
885 oop obj = CompressedOops::decode_not_null(o);
886 if (_heap->in_collection_set(obj)) {
887 shenandoah_assert_marked(p, obj);
888 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
889 if (oopDesc::equals_raw(resolved, obj)) {
890 resolved = _heap->evacuate_object(obj, _thread);
891 }
892 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
893 }
894 }
895 }
896
897 public:
898 void do_oop(oop* p) {
899 do_oop_work(p);
900 }
901 void do_oop(narrowOop* p) {
902 do_oop_work(p);
903 }
904 };
905
906 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
907 private:
908 ShenandoahHeap* const _heap;
909 Thread* const _thread;
910 public:
911 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
912 _heap(heap), _thread(Thread::current()) {}
913
914 void do_object(oop p) {
915 shenandoah_assert_marked(NULL, p);
916 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
917 _heap->evacuate_object(p, _thread);
918 }
919 }
920 };
921
922 class ShenandoahEvacuationTask : public AbstractGangTask {
923 private:
924 ShenandoahHeap* const _sh;
925 ShenandoahCollectionSet* const _cs;
926 bool _concurrent;
927 public:
928 ShenandoahEvacuationTask(ShenandoahHeap* sh,
929 ShenandoahCollectionSet* cs,
930 bool concurrent) :
931 AbstractGangTask("Parallel Evacuation Task"),
932 _sh(sh),
933 _cs(cs),
934 _concurrent(concurrent)
935 {}
936
937 void work(uint worker_id) {
938 if (_concurrent) {
939 ShenandoahConcurrentWorkerSession worker_session(worker_id);
940 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
941 ShenandoahEvacOOMScope oom_evac_scope;
942 do_work();
943 } else {
944 ShenandoahParallelWorkerSession worker_session(worker_id);
945 ShenandoahEvacOOMScope oom_evac_scope;
946 do_work();
947 }
948 }
949
950 private:
951 void do_work() {
952 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
953 ShenandoahHeapRegion* r;
954 while ((r =_cs->claim_next()) != NULL) {
955 assert(r->has_live(), "all-garbage regions are reclaimed early");
956 _sh->marked_object_iterate(r, &cl);
957
958 if (ShenandoahPacing) {
959 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
960 }
961
962 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
963 break;
964 }
965 }
966 }
967 };
968
969 void ShenandoahHeap::trash_cset_regions() {
970 ShenandoahHeapLocker locker(lock());
971
972 ShenandoahCollectionSet* set = collection_set();
973 ShenandoahHeapRegion* r;
974 set->clear_current_index();
975 while ((r = set->next()) != NULL) {
976 r->make_trash();
977 }
978 collection_set()->clear();
979 }
980
981 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
982 st->print_cr("Heap Regions:");
983 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
984 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
985 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
986 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
987
988 for (size_t i = 0; i < num_regions(); i++) {
989 get_region(i)->print_on(st);
990 }
991 }
992
993 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
994 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
995
996 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
997 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
998 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
999 size_t index = start->region_number() + required_regions - 1;
1000
1001 assert(!start->has_live(), "liveness must be zero");
1002
1003 for(size_t i = 0; i < required_regions; i++) {
1004 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1005 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1006 ShenandoahHeapRegion* region = get_region(index --);
1007
1008 assert(region->is_humongous(), "expect correct humongous start or continuation");
1009 assert(!region->is_cset(), "Humongous region should not be in collection set");
1010
1011 region->make_trash_immediate();
1012 }
1013 }
1014
1015 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1016 public:
1017 void do_thread(Thread* thread) {
1018 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1019 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1020 gclab->retire();
1021 }
1022 };
1023
1024 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1025 if (UseTLAB) {
1026 CollectedHeap::ensure_parsability(retire_tlabs);
1027 }
1028 ShenandoahRetireGCLABClosure cl;
1029 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1030 cl.do_thread(t);
1031 }
1032 workers()->threads_do(&cl);
1033 _safepoint_workers->threads_do(&cl);
1034 }
1035
1036 void ShenandoahHeap::resize_tlabs() {
1037 CollectedHeap::resize_all_tlabs();
1038 }
1039
1040 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1041 private:
1042 ShenandoahRootEvacuator* _rp;
1043
1044 public:
1045 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1046 AbstractGangTask("Shenandoah evacuate and update roots"),
1047 _rp(rp) {}
1048
1049 void work(uint worker_id) {
1050 ShenandoahParallelWorkerSession worker_session(worker_id);
1051 ShenandoahEvacOOMScope oom_evac_scope;
1052 ShenandoahEvacuateUpdateRootsClosure cl;
1053
1054 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1055 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1056 }
1057 };
1058
1059 void ShenandoahHeap::evacuate_and_update_roots() {
1060 #if defined(COMPILER2) || INCLUDE_JVMCI
1061 DerivedPointerTable::clear();
1062 #endif
1063 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1064
1065 {
1066 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1067 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1068 workers()->run_task(&roots_task);
1069 }
1070
1071 #if defined(COMPILER2) || INCLUDE_JVMCI
1072 DerivedPointerTable::update_pointers();
1073 #endif
1074 }
1075
1076 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1077 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1078
1079 CodeBlobToOopClosure blobsCl(cl, false);
1080 CLDToOopClosure cldCl(cl, ClassLoaderData::_claim_strong);
1081
1082 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1083 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1084 }
1085
1086 // Returns size in bytes
1087 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1088 if (ShenandoahElasticTLAB) {
1089 // With Elastic TLABs, return the max allowed size, and let the allocation path
1090 // figure out the safe size for current allocation.
1091 return ShenandoahHeapRegion::max_tlab_size_bytes();
1092 } else {
1093 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1094 }
1095 }
1096
1097 size_t ShenandoahHeap::max_tlab_size() const {
1098 // Returns size in words
1099 return ShenandoahHeapRegion::max_tlab_size_words();
1100 }
1101
1102 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1103 public:
1104 void do_thread(Thread* thread) {
1105 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1106 gclab->retire();
1107 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1108 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1109 }
1110 }
1111 };
1112
1113 void ShenandoahHeap::retire_and_reset_gclabs() {
1114 ShenandoahRetireAndResetGCLABClosure cl;
1115 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1116 cl.do_thread(t);
1117 }
1118 workers()->threads_do(&cl);
1119 _safepoint_workers->threads_do(&cl);
1120 }
1121
1122 void ShenandoahHeap::collect(GCCause::Cause cause) {
1123 control_thread()->request_gc(cause);
1124 }
1125
1126 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1127 //assert(false, "Shouldn't need to do full collections");
1128 }
1129
1130 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1131 return _shenandoah_policy;
1132 }
1133
1134 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1135 Space* sp = heap_region_containing(addr);
1136 if (sp != NULL) {
1137 return sp->block_start(addr);
1138 }
1139 return NULL;
1140 }
1141
1142 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1143 Space* sp = heap_region_containing(addr);
1144 assert(sp != NULL, "block_size of address outside of heap");
1145 return sp->block_size(addr);
1146 }
1147
1148 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1149 Space* sp = heap_region_containing(addr);
1150 return sp->block_is_obj(addr);
1151 }
1152
1153 jlong ShenandoahHeap::millis_since_last_gc() {
1154 double v = heuristics()->time_since_last_gc() * 1000;
1155 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1156 return (jlong)v;
1157 }
1158
1159 void ShenandoahHeap::prepare_for_verify() {
1160 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1161 make_parsable(false);
1162 }
1163 }
1164
1165 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1166 workers()->print_worker_threads_on(st);
1167 if (ShenandoahStringDedup::is_enabled()) {
1168 ShenandoahStringDedup::print_worker_threads_on(st);
1169 }
1170 }
1171
1172 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1173 workers()->threads_do(tcl);
1174 _safepoint_workers->threads_do(tcl);
1175 if (ShenandoahStringDedup::is_enabled()) {
1176 ShenandoahStringDedup::threads_do(tcl);
1177 }
1178 }
1179
1180 void ShenandoahHeap::print_tracing_info() const {
1181 LogTarget(Info, gc, stats) lt;
1182 if (lt.is_enabled()) {
1183 ResourceMark rm;
1184 LogStream ls(lt);
1185
1186 phase_timings()->print_on(&ls);
1187
1188 ls.cr();
1189 ls.cr();
1190
1191 shenandoah_policy()->print_gc_stats(&ls);
1192
1193 ls.cr();
1194 ls.cr();
1195
1196 if (ShenandoahPacing) {
1197 pacer()->print_on(&ls);
1198 }
1199
1200 ls.cr();
1201 ls.cr();
1202
1203 if (ShenandoahAllocationTrace) {
1204 assert(alloc_tracker() != NULL, "Must be");
1205 alloc_tracker()->print_on(&ls);
1206 } else {
1207 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1208 }
1209 }
1210 }
1211
1212 void ShenandoahHeap::verify(VerifyOption vo) {
1213 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1214 if (ShenandoahVerify) {
1215 verifier()->verify_generic(vo);
1216 } else {
1217 // TODO: Consider allocating verification bitmaps on demand,
1218 // and turn this on unconditionally.
1219 }
1220 }
1221 }
1222 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1223 return _free_set->capacity();
1224 }
1225
1226 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1227 private:
1228 MarkBitMap* _bitmap;
1229 Stack<oop,mtGC>* _oop_stack;
1230
1231 template <class T>
1232 void do_oop_work(T* p) {
1233 T o = RawAccess<>::oop_load(p);
1234 if (!CompressedOops::is_null(o)) {
1235 oop obj = CompressedOops::decode_not_null(o);
1236 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1237 assert(oopDesc::is_oop(obj), "must be a valid oop");
1238 if (!_bitmap->is_marked((HeapWord*) obj)) {
1239 _bitmap->mark((HeapWord*) obj);
1240 _oop_stack->push(obj);
1241 }
1242 }
1243 }
1244 public:
1245 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1246 _bitmap(bitmap), _oop_stack(oop_stack) {}
1247 void do_oop(oop* p) { do_oop_work(p); }
1248 void do_oop(narrowOop* p) { do_oop_work(p); }
1249 };
1250
1251 /*
1252 * This is public API, used in preparation of object_iterate().
1253 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1254 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1255 * control, we call SH::make_tlabs_parsable().
1256 */
1257 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1258 // No-op.
1259 }
1260
1261 /*
1262 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1263 *
1264 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1265 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1266 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1267 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1268 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1269 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1270 * wiped the bitmap in preparation for next marking).
1271 *
1272 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1273 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1274 * is allowed to report dead objects, but is not required to do so.
1275 */
1276 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1277 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1278 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1279 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1280 return;
1281 }
1282
1283 // Reset bitmap
1284 _aux_bit_map.clear();
1285
1286 Stack<oop,mtGC> oop_stack;
1287
1288 // First, we process all GC roots. This populates the work stack with initial objects.
1289 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1290 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1291 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1292 CodeBlobToOopClosure blobs(&oops, false);
1293 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1294
1295 // Work through the oop stack to traverse heap.
1296 while (! oop_stack.is_empty()) {
1297 oop obj = oop_stack.pop();
1298 assert(oopDesc::is_oop(obj), "must be a valid oop");
1299 cl->do_object(obj);
1300 obj->oop_iterate(&oops);
1301 }
1302
1303 assert(oop_stack.is_empty(), "should be empty");
1304
1305 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1306 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1307 }
1308 }
1309
1310 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1311 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1312 object_iterate(cl);
1313 }
1314
1315 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1316 for (size_t i = 0; i < num_regions(); i++) {
1317 ShenandoahHeapRegion* current = get_region(i);
1318 blk->heap_region_do(current);
1319 }
1320 }
1321
1322 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1323 private:
1324 ShenandoahHeap* const _heap;
1325 ShenandoahHeapRegionClosure* const _blk;
1326
1327 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1328 volatile size_t _index;
1329 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1330
1331 public:
1332 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1333 AbstractGangTask("Parallel Region Task"),
1334 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1335
1336 void work(uint worker_id) {
1337 size_t stride = ShenandoahParallelRegionStride;
1338
1339 size_t max = _heap->num_regions();
1340 while (_index < max) {
1341 size_t cur = Atomic::add(stride, &_index) - stride;
1342 size_t start = cur;
1343 size_t end = MIN2(cur + stride, max);
1344 if (start >= max) break;
1345
1346 for (size_t i = cur; i < end; i++) {
1347 ShenandoahHeapRegion* current = _heap->get_region(i);
1348 _blk->heap_region_do(current);
1349 }
1350 }
1351 }
1352 };
1353
1354 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1355 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1356 if (num_regions() > ShenandoahParallelRegionStride) {
1357 ShenandoahParallelHeapRegionTask task(blk);
1358 workers()->run_task(&task);
1359 } else {
1360 heap_region_iterate(blk);
1361 }
1362 }
1363
1364 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1365 private:
1366 ShenandoahMarkingContext* const _ctx;
1367 public:
1368 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1369
1370 void heap_region_do(ShenandoahHeapRegion* r) {
1371 if (r->is_active()) {
1372 r->clear_live_data();
1373 _ctx->capture_top_at_mark_start(r);
1374 } else {
1375 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1376 assert(_ctx->top_at_mark_start(r) == r->top(),
1377 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1378 }
1379 }
1380
1381 bool is_thread_safe() { return true; }
1382 };
1383
1384 void ShenandoahHeap::op_init_mark() {
1385 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1386 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1387
1388 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1389 assert(!marking_context()->is_complete(), "should not be complete");
1390
1391 if (ShenandoahVerify) {
1392 verifier()->verify_before_concmark();
1393 }
1394
1395 if (VerifyBeforeGC) {
1396 Universe::verify();
1397 }
1398
1399 set_concurrent_mark_in_progress(true);
1400 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1401 {
1402 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1403 make_parsable(true);
1404 }
1405
1406 {
1407 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1408 ShenandoahClearLivenessClosure clc;
1409 parallel_heap_region_iterate(&clc);
1410 }
1411
1412 // Make above changes visible to worker threads
1413 OrderAccess::fence();
1414
1415 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1416
1417 if (UseTLAB) {
1418 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1419 resize_tlabs();
1420 }
1421
1422 if (ShenandoahPacing) {
1423 pacer()->setup_for_mark();
1424 }
1425 }
1426
1427 void ShenandoahHeap::op_mark() {
1428 concurrent_mark()->mark_from_roots();
1429 }
1430
1431 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1432 private:
1433 ShenandoahMarkingContext* const _ctx;
1434 public:
1435 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1436
1437 void heap_region_do(ShenandoahHeapRegion* r) {
1438 if (r->is_active()) {
1439 HeapWord *tams = _ctx->top_at_mark_start(r);
1440 HeapWord *top = r->top();
1441 if (top > tams) {
1442 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1443 }
1444 } else {
1445 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1446 assert(_ctx->top_at_mark_start(r) == r->top(),
1447 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1448 }
1449 }
1450
1451 bool is_thread_safe() { return true; }
1452 };
1453
1454 void ShenandoahHeap::op_final_mark() {
1455 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1456
1457 // It is critical that we
1458 // evacuate roots right after finishing marking, so that we don't
1459 // get unmarked objects in the roots.
1460
1461 if (!cancelled_gc()) {
1462 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1463
1464 if (has_forwarded_objects()) {
1465 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1466 }
1467
1468 stop_concurrent_marking();
1469
1470 {
1471 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1472
1473 // All allocations past TAMS are implicitly live, adjust the region data.
1474 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1475 ShenandoahCompleteLivenessClosure cl;
1476 parallel_heap_region_iterate(&cl);
1477 }
1478
1479 {
1480 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1481
1482 make_parsable(true);
1483
1484 trash_cset_regions();
1485
1486 {
1487 ShenandoahHeapLocker locker(lock());
1488 _collection_set->clear();
1489 _free_set->clear();
1490
1491 heuristics()->choose_collection_set(_collection_set);
1492
1493 _free_set->rebuild();
1494 }
1495 }
1496
1497 // If collection set has candidates, start evacuation.
1498 // Otherwise, bypass the rest of the cycle.
1499 if (!collection_set()->is_empty()) {
1500 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1501
1502 if (ShenandoahVerify) {
1503 verifier()->verify_before_evacuation();
1504 }
1505
1506 set_evacuation_in_progress(true);
1507 // From here on, we need to update references.
1508 set_has_forwarded_objects(true);
1509
1510 evacuate_and_update_roots();
1511
1512 if (ShenandoahPacing) {
1513 pacer()->setup_for_evac();
1514 }
1515 } else {
1516 if (ShenandoahVerify) {
1517 verifier()->verify_after_concmark();
1518 }
1519
1520 if (VerifyAfterGC) {
1521 Universe::verify();
1522 }
1523 }
1524
1525 } else {
1526 concurrent_mark()->cancel();
1527 stop_concurrent_marking();
1528
1529 if (process_references()) {
1530 // Abandon reference processing right away: pre-cleaning must have failed.
1531 ReferenceProcessor *rp = ref_processor();
1532 rp->disable_discovery();
1533 rp->abandon_partial_discovery();
1534 rp->verify_no_references_recorded();
1535 }
1536 }
1537 }
1538
1539 void ShenandoahHeap::op_final_evac() {
1540 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1541
1542 set_evacuation_in_progress(false);
1543
1544 retire_and_reset_gclabs();
1545
1546 if (ShenandoahVerify) {
1547 verifier()->verify_after_evacuation();
1548 }
1549
1550 if (VerifyAfterGC) {
1551 Universe::verify();
1552 }
1553 }
1554
1555 void ShenandoahHeap::op_conc_evac() {
1556 ShenandoahEvacuationTask task(this, _collection_set, true);
1557 workers()->run_task(&task);
1558 }
1559
1560 void ShenandoahHeap::op_stw_evac() {
1561 ShenandoahEvacuationTask task(this, _collection_set, false);
1562 workers()->run_task(&task);
1563 }
1564
1565 void ShenandoahHeap::op_updaterefs() {
1566 update_heap_references(true);
1567 }
1568
1569 void ShenandoahHeap::op_cleanup() {
1570 free_set()->recycle_trash();
1571 }
1572
1573 void ShenandoahHeap::op_reset() {
1574 reset_mark_bitmap();
1575 }
1576
1577 void ShenandoahHeap::op_preclean() {
1578 concurrent_mark()->preclean_weak_refs();
1579 }
1580
1581 void ShenandoahHeap::op_init_traversal() {
1582 traversal_gc()->init_traversal_collection();
1583 }
1584
1585 void ShenandoahHeap::op_traversal() {
1586 traversal_gc()->concurrent_traversal_collection();
1587 }
1588
1589 void ShenandoahHeap::op_final_traversal() {
1590 traversal_gc()->final_traversal_collection();
1591 }
1592
1593 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1594 ShenandoahMetricsSnapshot metrics;
1595 metrics.snap_before();
1596
1597 full_gc()->do_it(cause);
1598 if (UseTLAB) {
1599 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1600 resize_all_tlabs();
1601 }
1602
1603 metrics.snap_after();
1604 metrics.print();
1605
1606 if (metrics.is_good_progress("Full GC")) {
1607 _progress_last_gc.set();
1608 } else {
1609 // Nothing to do. Tell the allocation path that we have failed to make
1610 // progress, and it can finally fail.
1611 _progress_last_gc.unset();
1612 }
1613 }
1614
1615 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1616 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1617 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1618 // some phase, we have to upgrade the Degenerate GC to Full GC.
1619
1620 clear_cancelled_gc();
1621
1622 ShenandoahMetricsSnapshot metrics;
1623 metrics.snap_before();
1624
1625 switch (point) {
1626 case _degenerated_traversal:
1627 {
1628 // Drop the collection set. Note: this leaves some already forwarded objects
1629 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1630 // workarounds in ShenandoahTraversalHeuristics.
1631
1632 ShenandoahHeapLocker locker(lock());
1633 collection_set()->clear_current_index();
1634 for (size_t i = 0; i < collection_set()->count(); i++) {
1635 ShenandoahHeapRegion* r = collection_set()->next();
1636 r->make_regular_bypass();
1637 }
1638 collection_set()->clear();
1639 }
1640 op_final_traversal();
1641 op_cleanup();
1642 return;
1643
1644 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1645 // but enters it at different points, depending on which concurrent phase had
1646 // degenerated.
1647
1648 case _degenerated_outside_cycle:
1649 // We have degenerated from outside the cycle, which means something is bad with
1650 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1651 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1652 // we can do the most aggressive degen cycle, which includes processing references and
1653 // class unloading, unless those features are explicitly disabled.
1654 //
1655 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1656 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1657 set_process_references(heuristics()->can_process_references());
1658 set_unload_classes(heuristics()->can_unload_classes());
1659
1660 if (heuristics()->can_do_traversal_gc()) {
1661 // Not possible to degenerate from here, upgrade to Full GC right away.
1662 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1663 op_degenerated_fail();
1664 return;
1665 }
1666
1667 op_reset();
1668
1669 op_init_mark();
1670 if (cancelled_gc()) {
1671 op_degenerated_fail();
1672 return;
1673 }
1674
1675 case _degenerated_mark:
1676 op_final_mark();
1677 if (cancelled_gc()) {
1678 op_degenerated_fail();
1679 return;
1680 }
1681
1682 op_cleanup();
1683
1684 case _degenerated_evac:
1685 // If heuristics thinks we should do the cycle, this flag would be set,
1686 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1687 if (is_evacuation_in_progress()) {
1688
1689 // Degeneration under oom-evac protocol might have left some objects in
1690 // collection set un-evacuated. Restart evacuation from the beginning to
1691 // capture all objects. For all the objects that are already evacuated,
1692 // it would be a simple check, which is supposed to be fast. This is also
1693 // safe to do even without degeneration, as CSet iterator is at beginning
1694 // in preparation for evacuation anyway.
1695 collection_set()->clear_current_index();
1696
1697 op_stw_evac();
1698 if (cancelled_gc()) {
1699 op_degenerated_fail();
1700 return;
1701 }
1702 }
1703
1704 // If heuristics thinks we should do the cycle, this flag would be set,
1705 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1706 if (has_forwarded_objects()) {
1707 op_init_updaterefs();
1708 if (cancelled_gc()) {
1709 op_degenerated_fail();
1710 return;
1711 }
1712 }
1713
1714 case _degenerated_updaterefs:
1715 if (has_forwarded_objects()) {
1716 op_final_updaterefs();
1717 if (cancelled_gc()) {
1718 op_degenerated_fail();
1719 return;
1720 }
1721 }
1722
1723 op_cleanup();
1724 break;
1725
1726 default:
1727 ShouldNotReachHere();
1728 }
1729
1730 if (ShenandoahVerify) {
1731 verifier()->verify_after_degenerated();
1732 }
1733
1734 if (VerifyAfterGC) {
1735 Universe::verify();
1736 }
1737
1738 metrics.snap_after();
1739 metrics.print();
1740
1741 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1742 // because that probably means the heap is overloaded and/or fragmented.
1743 if (!metrics.is_good_progress("Degenerated GC")) {
1744 _progress_last_gc.unset();
1745 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1746 op_degenerated_futile();
1747 } else {
1748 _progress_last_gc.set();
1749 }
1750 }
1751
1752 void ShenandoahHeap::op_degenerated_fail() {
1753 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1754 shenandoah_policy()->record_degenerated_upgrade_to_full();
1755 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1756 }
1757
1758 void ShenandoahHeap::op_degenerated_futile() {
1759 shenandoah_policy()->record_degenerated_upgrade_to_full();
1760 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1761 }
1762
1763 void ShenandoahHeap::stop_concurrent_marking() {
1764 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1765 if (!cancelled_gc()) {
1766 // If we needed to update refs, and concurrent marking has been cancelled,
1767 // we need to finish updating references.
1768 set_has_forwarded_objects(false);
1769 mark_complete_marking_context();
1770 }
1771 set_concurrent_mark_in_progress(false);
1772 }
1773
1774 void ShenandoahHeap::force_satb_flush_all_threads() {
1775 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1776 // No need to flush SATBs
1777 return;
1778 }
1779
1780 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1781 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1782 }
1783 // The threads are not "acquiring" their thread-local data, but it does not
1784 // hurt to "release" the updates here anyway.
1785 OrderAccess::fence();
1786 }
1787
1788 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1789 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1790 ShenandoahThreadLocalData::set_gc_state(t, state);
1791 }
1792 }
1793
1794 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1795 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1796 _gc_state.set_cond(mask, value);
1797 set_gc_state_all_threads(_gc_state.raw_value());
1798 }
1799
1800 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1801 set_gc_state_mask(MARKING, in_progress);
1802 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1803 }
1804
1805 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1806 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1807 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1808 }
1809
1810 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1811 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1812 set_gc_state_mask(EVACUATION, in_progress);
1813 }
1814
1815 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1816 // Initialize Brooks pointer for the next object
1817 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1818 ShenandoahBrooksPointer::initialize(oop(result));
1819 return result;
1820 }
1821
1822 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1823 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1824 }
1825
1826 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1827 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1828 }
1829
1830 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1831 if (CompressedOops::is_null(obj)) {
1832 return false;
1833 }
1834 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1835 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1836 return _mark_context->is_marked(obj);
1837 }
1838
1839 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1840 if (CompressedOops::is_null(obj)) {
1841 return false;
1842 }
1843 shenandoah_assert_not_forwarded(NULL, obj);
1844 return _mark_context->is_marked(obj);
1845 }
1846
1847 void ShenandoahHeap::ref_processing_init() {
1848 assert(_max_workers > 0, "Sanity");
1849
1850 _ref_processor =
1851 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1852 ParallelRefProcEnabled, // MT processing
1853 _max_workers, // Degree of MT processing
1854 true, // MT discovery
1855 _max_workers, // Degree of MT discovery
1856 false, // Reference discovery is not atomic
1857 NULL, // No closure, should be installed before use
1858 true); // Scale worker threads
1859
1860 shenandoah_assert_rp_isalive_not_installed();
1861 }
1862
1863 GCTracer* ShenandoahHeap::tracer() {
1864 return shenandoah_policy()->tracer();
1865 }
1866
1867 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1868 return _free_set->used();
1869 }
1870
1871 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1872 if (try_cancel_gc()) {
1873 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1874 log_info(gc)("%s", msg.buffer());
1875 Events::log(Thread::current(), "%s", msg.buffer());
1876 }
1877 }
1878
1879 uint ShenandoahHeap::max_workers() {
1880 return _max_workers;
1881 }
1882
1883 void ShenandoahHeap::stop() {
1884 // The shutdown sequence should be able to terminate when GC is running.
1885
1886 // Step 0. Notify policy to disable event recording.
1887 _shenandoah_policy->record_shutdown();
1888
1889 // Step 1. Notify control thread that we are in shutdown.
1890 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1891 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1892 control_thread()->prepare_for_graceful_shutdown();
1893
1894 // Step 2. Notify GC workers that we are cancelling GC.
1895 cancel_gc(GCCause::_shenandoah_stop_vm);
1896
1897 // Step 3. Wait until GC worker exits normally.
1898 control_thread()->stop();
1899
1900 // Step 4. Stop String Dedup thread if it is active
1901 if (ShenandoahStringDedup::is_enabled()) {
1902 ShenandoahStringDedup::stop();
1903 }
1904 }
1905
1906 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1907 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1908
1909 ShenandoahGCPhase root_phase(full_gc ?
1910 ShenandoahPhaseTimings::full_gc_purge :
1911 ShenandoahPhaseTimings::purge);
1912
1913 ShenandoahIsAliveSelector alive;
1914 BoolObjectClosure* is_alive = alive.is_alive_closure();
1915
1916 bool purged_class;
1917
1918 // Unload classes and purge SystemDictionary.
1919 {
1920 ShenandoahGCPhase phase(full_gc ?
1921 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1922 ShenandoahPhaseTimings::purge_class_unload);
1923 purged_class = SystemDictionary::do_unloading(gc_timer());
1924 }
1925
1926 {
1927 ShenandoahGCPhase phase(full_gc ?
1928 ShenandoahPhaseTimings::full_gc_purge_par :
1929 ShenandoahPhaseTimings::purge_par);
1930 uint active = _workers->active_workers();
1931 StringDedupUnlinkOrOopsDoClosure dedup_cl(is_alive, NULL);
1932 ParallelCleaningTask unlink_task(is_alive, &dedup_cl, active, purged_class);
1933 _workers->run_task(&unlink_task);
1934 }
1935
1936 if (ShenandoahStringDedup::is_enabled()) {
1937 ShenandoahGCPhase phase(full_gc ?
1938 ShenandoahPhaseTimings::full_gc_purge_string_dedup :
1939 ShenandoahPhaseTimings::purge_string_dedup);
1940 ShenandoahStringDedup::parallel_cleanup();
1941 }
1942
1943 {
1944 ShenandoahGCPhase phase(full_gc ?
1945 ShenandoahPhaseTimings::full_gc_purge_cldg :
1946 ShenandoahPhaseTimings::purge_cldg);
1947 ClassLoaderDataGraph::purge();
1948 }
1949 }
1950
1951 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1952 set_gc_state_mask(HAS_FORWARDED, cond);
1953 }
1954
1955 void ShenandoahHeap::set_process_references(bool pr) {
1956 _process_references.set_cond(pr);
1957 }
1958
1959 void ShenandoahHeap::set_unload_classes(bool uc) {
1960 _unload_classes.set_cond(uc);
1961 }
1962
1963 bool ShenandoahHeap::process_references() const {
1964 return _process_references.is_set();
1965 }
1966
1967 bool ShenandoahHeap::unload_classes() const {
1968 return _unload_classes.is_set();
1969 }
1970
1971 address ShenandoahHeap::in_cset_fast_test_addr() {
1972 ShenandoahHeap* heap = ShenandoahHeap::heap();
1973 assert(heap->collection_set() != NULL, "Sanity");
1974 return (address) heap->collection_set()->biased_map_address();
1975 }
1976
1977 address ShenandoahHeap::cancelled_gc_addr() {
1978 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1979 }
1980
1981 address ShenandoahHeap::gc_state_addr() {
1982 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1983 }
1984
1985 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1986 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1987 }
1988
1989 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1990 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1991 }
1992
1993 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1994 _degenerated_gc_in_progress.set_cond(in_progress);
1995 }
1996
1997 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1998 _full_gc_in_progress.set_cond(in_progress);
1999 }
2000
2001 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2002 assert (is_full_gc_in_progress(), "should be");
2003 _full_gc_move_in_progress.set_cond(in_progress);
2004 }
2005
2006 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2007 set_gc_state_mask(UPDATEREFS, in_progress);
2008 }
2009
2010 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2011 ShenandoahCodeRoots::add_nmethod(nm);
2012 }
2013
2014 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2015 ShenandoahCodeRoots::remove_nmethod(nm);
2016 }
2017
2018 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2019 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2020 ShenandoahHeapLocker locker(lock());
2021 heap_region_containing(o)->make_pinned();
2022 return o;
2023 }
2024
2025 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2026 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2027 ShenandoahHeapLocker locker(lock());
2028 heap_region_containing(o)->make_unpinned();
2029 }
2030
2031 GCTimer* ShenandoahHeap::gc_timer() const {
2032 return _gc_timer;
2033 }
2034
2035 #ifdef ASSERT
2036 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2037 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2038
2039 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2040 if (UseDynamicNumberOfGCThreads ||
2041 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2042 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2043 } else {
2044 // Use ParallelGCThreads inside safepoints
2045 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2046 }
2047 } else {
2048 if (UseDynamicNumberOfGCThreads ||
2049 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2050 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2051 } else {
2052 // Use ConcGCThreads outside safepoints
2053 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2054 }
2055 }
2056 }
2057 #endif
2058
2059 ShenandoahVerifier* ShenandoahHeap::verifier() {
2060 guarantee(ShenandoahVerify, "Should be enabled");
2061 assert (_verifier != NULL, "sanity");
2062 return _verifier;
2063 }
2064
2065 template<class T>
2066 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2067 private:
2068 T cl;
2069 ShenandoahHeap* _heap;
2070 ShenandoahRegionIterator* _regions;
2071 bool _concurrent;
2072 public:
2073 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2074 AbstractGangTask("Concurrent Update References Task"),
2075 cl(T()),
2076 _heap(ShenandoahHeap::heap()),
2077 _regions(regions),
2078 _concurrent(concurrent) {
2079 }
2080
2081 void work(uint worker_id) {
2082 if (_concurrent) {
2083 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2084 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2085 do_work();
2086 } else {
2087 ShenandoahParallelWorkerSession worker_session(worker_id);
2088 do_work();
2089 }
2090 }
2091
2092 private:
2093 void do_work() {
2094 ShenandoahHeapRegion* r = _regions->next();
2095 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2096 while (r != NULL) {
2097 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2098 assert (top_at_start_ur >= r->bottom(), "sanity");
2099 if (r->is_active() && !r->is_cset()) {
2100 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2101 }
2102 if (ShenandoahPacing) {
2103 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2104 }
2105 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2106 return;
2107 }
2108 r = _regions->next();
2109 }
2110 }
2111 };
2112
2113 void ShenandoahHeap::update_heap_references(bool concurrent) {
2114 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2115 workers()->run_task(&task);
2116 }
2117
2118 void ShenandoahHeap::op_init_updaterefs() {
2119 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2120
2121 set_evacuation_in_progress(false);
2122
2123 retire_and_reset_gclabs();
2124
2125 if (ShenandoahVerify) {
2126 verifier()->verify_before_updaterefs();
2127 }
2128
2129 set_update_refs_in_progress(true);
2130 make_parsable(true);
2131 for (uint i = 0; i < num_regions(); i++) {
2132 ShenandoahHeapRegion* r = get_region(i);
2133 r->set_concurrent_iteration_safe_limit(r->top());
2134 }
2135
2136 // Reset iterator.
2137 _update_refs_iterator.reset();
2138
2139 if (ShenandoahPacing) {
2140 pacer()->setup_for_updaterefs();
2141 }
2142 }
2143
2144 void ShenandoahHeap::op_final_updaterefs() {
2145 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2146
2147 // Check if there is left-over work, and finish it
2148 if (_update_refs_iterator.has_next()) {
2149 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2150
2151 // Finish updating references where we left off.
2152 clear_cancelled_gc();
2153 update_heap_references(false);
2154 }
2155
2156 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2157 // everything. On degenerated paths, cancelled gc would not be set anyway.
2158 if (cancelled_gc()) {
2159 clear_cancelled_gc();
2160 }
2161 assert(!cancelled_gc(), "Should have been done right before");
2162
2163 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2164 ShenandoahPhaseTimings::degen_gc_update_roots:
2165 ShenandoahPhaseTimings::final_update_refs_roots);
2166
2167 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2168
2169 trash_cset_regions();
2170 set_has_forwarded_objects(false);
2171 set_update_refs_in_progress(false);
2172
2173 if (ShenandoahVerify) {
2174 verifier()->verify_after_updaterefs();
2175 }
2176
2177 if (VerifyAfterGC) {
2178 Universe::verify();
2179 }
2180
2181 {
2182 ShenandoahHeapLocker locker(lock());
2183 _free_set->rebuild();
2184 }
2185 }
2186
2187 #ifdef ASSERT
2188 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2189 _lock.assert_owned_by_current_thread();
2190 }
2191
2192 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2193 _lock.assert_not_owned_by_current_thread();
2194 }
2195
2196 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2197 _lock.assert_owned_by_current_thread_or_safepoint();
2198 }
2199 #endif
2200
2201 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2202 print_on(st);
2203 print_heap_regions_on(st);
2204 }
2205
2206 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2207 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2208
2209 size_t regions_from = _bitmap_regions_per_slice * slice;
2210 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2211 for (size_t g = regions_from; g < regions_to; g++) {
2212 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2213 if (skip_self && g == r->region_number()) continue;
2214 if (get_region(g)->is_committed()) {
2215 return true;
2216 }
2217 }
2218 return false;
2219 }
2220
2221 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2222 assert_heaplock_owned_by_current_thread();
2223
2224 if (is_bitmap_slice_committed(r, true)) {
2225 // Some other region from the group is already committed, meaning the bitmap
2226 // slice is already committed, we exit right away.
2227 return true;
2228 }
2229
2230 // Commit the bitmap slice:
2231 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2232 size_t off = _bitmap_bytes_per_slice * slice;
2233 size_t len = _bitmap_bytes_per_slice;
2234 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2235 return false;
2236 }
2237 return true;
2238 }
2239
2240 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2241 assert_heaplock_owned_by_current_thread();
2242
2243 if (is_bitmap_slice_committed(r, true)) {
2244 // Some other region from the group is still committed, meaning the bitmap
2245 // slice is should stay committed, exit right away.
2246 return true;
2247 }
2248
2249 // Uncommit the bitmap slice:
2250 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2251 size_t off = _bitmap_bytes_per_slice * slice;
2252 size_t len = _bitmap_bytes_per_slice;
2253 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2254 return false;
2255 }
2256 return true;
2257 }
2258
2259 void ShenandoahHeap::safepoint_synchronize_begin() {
2260 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2261 SuspendibleThreadSet::synchronize();
2262 }
2263 }
2264
2265 void ShenandoahHeap::safepoint_synchronize_end() {
2266 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2267 SuspendibleThreadSet::desynchronize();
2268 }
2269 }
2270
2271 void ShenandoahHeap::vmop_entry_init_mark() {
2272 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2273 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2274 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2275
2276 try_inject_alloc_failure();
2277 VM_ShenandoahInitMark op;
2278 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2279 }
2280
2281 void ShenandoahHeap::vmop_entry_final_mark() {
2282 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2283 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2284 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2285
2286 try_inject_alloc_failure();
2287 VM_ShenandoahFinalMarkStartEvac op;
2288 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2289 }
2290
2291 void ShenandoahHeap::vmop_entry_final_evac() {
2292 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2293 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2294 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2295
2296 VM_ShenandoahFinalEvac op;
2297 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2298 }
2299
2300 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2301 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2302 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2303 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2304
2305 try_inject_alloc_failure();
2306 VM_ShenandoahInitUpdateRefs op;
2307 VMThread::execute(&op);
2308 }
2309
2310 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2311 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2312 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2313 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2314
2315 try_inject_alloc_failure();
2316 VM_ShenandoahFinalUpdateRefs op;
2317 VMThread::execute(&op);
2318 }
2319
2320 void ShenandoahHeap::vmop_entry_init_traversal() {
2321 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2322 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2323 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2324
2325 try_inject_alloc_failure();
2326 VM_ShenandoahInitTraversalGC op;
2327 VMThread::execute(&op);
2328 }
2329
2330 void ShenandoahHeap::vmop_entry_final_traversal() {
2331 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2332 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2333 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2334
2335 try_inject_alloc_failure();
2336 VM_ShenandoahFinalTraversalGC op;
2337 VMThread::execute(&op);
2338 }
2339
2340 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2341 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2342 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2343 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2344
2345 try_inject_alloc_failure();
2346 VM_ShenandoahFullGC op(cause);
2347 VMThread::execute(&op);
2348 }
2349
2350 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2351 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2352 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2353 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2354
2355 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2356 VMThread::execute(°enerated_gc);
2357 }
2358
2359 void ShenandoahHeap::entry_init_mark() {
2360 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2361 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2362 const char* msg = init_mark_event_message();
2363 GCTraceTime(Info, gc) time(msg, gc_timer());
2364 EventMark em("%s", msg);
2365
2366 ShenandoahWorkerScope scope(workers(),
2367 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2368 "init marking");
2369
2370 op_init_mark();
2371 }
2372
2373 void ShenandoahHeap::entry_final_mark() {
2374 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2375 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2376 const char* msg = final_mark_event_message();
2377 GCTraceTime(Info, gc) time(msg, gc_timer());
2378 EventMark em("%s", msg);
2379
2380 ShenandoahWorkerScope scope(workers(),
2381 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2382 "final marking");
2383
2384 op_final_mark();
2385 }
2386
2387 void ShenandoahHeap::entry_final_evac() {
2388 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2389 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2390 static const char* msg = "Pause Final Evac";
2391 GCTraceTime(Info, gc) time(msg, gc_timer());
2392 EventMark em("%s", msg);
2393
2394 op_final_evac();
2395 }
2396
2397 void ShenandoahHeap::entry_init_updaterefs() {
2398 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2399 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2400
2401 static const char* msg = "Pause Init Update Refs";
2402 GCTraceTime(Info, gc) time(msg, gc_timer());
2403 EventMark em("%s", msg);
2404
2405 // No workers used in this phase, no setup required
2406
2407 op_init_updaterefs();
2408 }
2409
2410 void ShenandoahHeap::entry_final_updaterefs() {
2411 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2412 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2413
2414 static const char* msg = "Pause Final Update Refs";
2415 GCTraceTime(Info, gc) time(msg, gc_timer());
2416 EventMark em("%s", msg);
2417
2418 ShenandoahWorkerScope scope(workers(),
2419 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2420 "final reference update");
2421
2422 op_final_updaterefs();
2423 }
2424
2425 void ShenandoahHeap::entry_init_traversal() {
2426 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2427 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2428
2429 static const char* msg = "Pause Init Traversal";
2430 GCTraceTime(Info, gc) time(msg, gc_timer());
2431 EventMark em("%s", msg);
2432
2433 ShenandoahWorkerScope scope(workers(),
2434 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2435 "init traversal");
2436
2437 op_init_traversal();
2438 }
2439
2440 void ShenandoahHeap::entry_final_traversal() {
2441 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2442 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2443
2444 static const char* msg = "Pause Final Traversal";
2445 GCTraceTime(Info, gc) time(msg, gc_timer());
2446 EventMark em("%s", msg);
2447
2448 ShenandoahWorkerScope scope(workers(),
2449 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2450 "final traversal");
2451
2452 op_final_traversal();
2453 }
2454
2455 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2456 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2457 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2458
2459 static const char* msg = "Pause Full";
2460 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2461 EventMark em("%s", msg);
2462
2463 ShenandoahWorkerScope scope(workers(),
2464 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2465 "full gc");
2466
2467 op_full(cause);
2468 }
2469
2470 void ShenandoahHeap::entry_degenerated(int point) {
2471 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2472 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2473
2474 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2475 const char* msg = degen_event_message(dpoint);
2476 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2477 EventMark em("%s", msg);
2478
2479 ShenandoahWorkerScope scope(workers(),
2480 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2481 "stw degenerated gc");
2482
2483 set_degenerated_gc_in_progress(true);
2484 op_degenerated(dpoint);
2485 set_degenerated_gc_in_progress(false);
2486 }
2487
2488 void ShenandoahHeap::entry_mark() {
2489 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2490
2491 const char* msg = conc_mark_event_message();
2492 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2493 EventMark em("%s", msg);
2494
2495 ShenandoahWorkerScope scope(workers(),
2496 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2497 "concurrent marking");
2498
2499 try_inject_alloc_failure();
2500 op_mark();
2501 }
2502
2503 void ShenandoahHeap::entry_evac() {
2504 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2505 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2506
2507 static const char* msg = "Concurrent evacuation";
2508 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2509 EventMark em("%s", msg);
2510
2511 ShenandoahWorkerScope scope(workers(),
2512 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2513 "concurrent evacuation");
2514
2515 try_inject_alloc_failure();
2516 op_conc_evac();
2517 }
2518
2519 void ShenandoahHeap::entry_updaterefs() {
2520 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2521
2522 static const char* msg = "Concurrent update references";
2523 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2524 EventMark em("%s", msg);
2525
2526 ShenandoahWorkerScope scope(workers(),
2527 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2528 "concurrent reference update");
2529
2530 try_inject_alloc_failure();
2531 op_updaterefs();
2532 }
2533 void ShenandoahHeap::entry_cleanup() {
2534 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2535
2536 static const char* msg = "Concurrent cleanup";
2537 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2538 EventMark em("%s", msg);
2539
2540 // This phase does not use workers, no need for setup
2541
2542 try_inject_alloc_failure();
2543 op_cleanup();
2544 }
2545
2546 void ShenandoahHeap::entry_reset() {
2547 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2548
2549 static const char* msg = "Concurrent reset";
2550 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2551 EventMark em("%s", msg);
2552
2553 ShenandoahWorkerScope scope(workers(),
2554 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2555 "concurrent reset");
2556
2557 try_inject_alloc_failure();
2558 op_reset();
2559 }
2560
2561 void ShenandoahHeap::entry_preclean() {
2562 if (ShenandoahPreclean && process_references()) {
2563 static const char* msg = "Concurrent precleaning";
2564 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2565 EventMark em("%s", msg);
2566
2567 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2568
2569 ShenandoahWorkerScope scope(workers(),
2570 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2571 "concurrent preclean",
2572 /* check_workers = */ false);
2573
2574 try_inject_alloc_failure();
2575 op_preclean();
2576 }
2577 }
2578
2579 void ShenandoahHeap::entry_traversal() {
2580 static const char* msg = "Concurrent traversal";
2581 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2582 EventMark em("%s", msg);
2583
2584 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2585
2586 ShenandoahWorkerScope scope(workers(),
2587 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2588 "concurrent traversal");
2589
2590 try_inject_alloc_failure();
2591 op_traversal();
2592 }
2593
2594 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2595 static const char *msg = "Concurrent uncommit";
2596 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2597 EventMark em("%s", msg);
2598
2599 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2600
2601 op_uncommit(shrink_before);
2602 }
2603
2604 void ShenandoahHeap::try_inject_alloc_failure() {
2605 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2606 _inject_alloc_failure.set();
2607 os::naked_short_sleep(1);
2608 if (cancelled_gc()) {
2609 log_info(gc)("Allocation failure was successfully injected");
2610 }
2611 }
2612 }
2613
2614 bool ShenandoahHeap::should_inject_alloc_failure() {
2615 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2616 }
2617
2618 void ShenandoahHeap::initialize_serviceability() {
2619 _memory_pool = new ShenandoahMemoryPool(this);
2620 _cycle_memory_manager.add_pool(_memory_pool);
2621 _stw_memory_manager.add_pool(_memory_pool);
2622 }
2623
2624 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2625 GrowableArray<GCMemoryManager*> memory_managers(2);
2626 memory_managers.append(&_cycle_memory_manager);
2627 memory_managers.append(&_stw_memory_manager);
2628 return memory_managers;
2629 }
2630
2631 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2632 GrowableArray<MemoryPool*> memory_pools(1);
2633 memory_pools.append(_memory_pool);
2634 return memory_pools;
2635 }
2636
2637 void ShenandoahHeap::enter_evacuation() {
2638 _oom_evac_handler.enter_evacuation();
2639 }
2640
2641 void ShenandoahHeap::leave_evacuation() {
2642 _oom_evac_handler.leave_evacuation();
2643 }
2644
2645 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2646 _heap(ShenandoahHeap::heap()),
2647 _index(0) {}
2648
2649 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2650 _heap(heap),
2651 _index(0) {}
2652
2653 void ShenandoahRegionIterator::reset() {
2654 _index = 0;
2655 }
2656
2657 bool ShenandoahRegionIterator::has_next() const {
2658 return _index < _heap->num_regions();
2659 }
2660
2661 char ShenandoahHeap::gc_state() const {
2662 return _gc_state.raw_value();
2663 }
2664
2665 void ShenandoahHeap::deduplicate_string(oop str) {
2666 assert(java_lang_String::is_instance(str), "invariant");
2667
2668 if (ShenandoahStringDedup::is_enabled()) {
2669 ShenandoahStringDedup::deduplicate(str);
2670 }
2671 }
2672
2673 const char* ShenandoahHeap::init_mark_event_message() const {
2674 bool update_refs = has_forwarded_objects();
2675 bool proc_refs = process_references();
2676 bool unload_cls = unload_classes();
2677
2678 if (update_refs && proc_refs && unload_cls) {
2679 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2680 } else if (update_refs && proc_refs) {
2681 return "Pause Init Mark (update refs) (process weakrefs)";
2682 } else if (update_refs && unload_cls) {
2683 return "Pause Init Mark (update refs) (unload classes)";
2684 } else if (proc_refs && unload_cls) {
2685 return "Pause Init Mark (process weakrefs) (unload classes)";
2686 } else if (update_refs) {
2687 return "Pause Init Mark (update refs)";
2688 } else if (proc_refs) {
2689 return "Pause Init Mark (process weakrefs)";
2690 } else if (unload_cls) {
2691 return "Pause Init Mark (unload classes)";
2692 } else {
2693 return "Pause Init Mark";
2694 }
2695 }
2696
2697 const char* ShenandoahHeap::final_mark_event_message() const {
2698 bool update_refs = has_forwarded_objects();
2699 bool proc_refs = process_references();
2700 bool unload_cls = unload_classes();
2701
2702 if (update_refs && proc_refs && unload_cls) {
2703 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2704 } else if (update_refs && proc_refs) {
2705 return "Pause Final Mark (update refs) (process weakrefs)";
2706 } else if (update_refs && unload_cls) {
2707 return "Pause Final Mark (update refs) (unload classes)";
2708 } else if (proc_refs && unload_cls) {
2709 return "Pause Final Mark (process weakrefs) (unload classes)";
2710 } else if (update_refs) {
2711 return "Pause Final Mark (update refs)";
2712 } else if (proc_refs) {
2713 return "Pause Final Mark (process weakrefs)";
2714 } else if (unload_cls) {
2715 return "Pause Final Mark (unload classes)";
2716 } else {
2717 return "Pause Final Mark";
2718 }
2719 }
2720
2721 const char* ShenandoahHeap::conc_mark_event_message() const {
2722 bool update_refs = has_forwarded_objects();
2723 bool proc_refs = process_references();
2724 bool unload_cls = unload_classes();
2725
2726 if (update_refs && proc_refs && unload_cls) {
2727 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2728 } else if (update_refs && proc_refs) {
2729 return "Concurrent marking (update refs) (process weakrefs)";
2730 } else if (update_refs && unload_cls) {
2731 return "Concurrent marking (update refs) (unload classes)";
2732 } else if (proc_refs && unload_cls) {
2733 return "Concurrent marking (process weakrefs) (unload classes)";
2734 } else if (update_refs) {
2735 return "Concurrent marking (update refs)";
2736 } else if (proc_refs) {
2737 return "Concurrent marking (process weakrefs)";
2738 } else if (unload_cls) {
2739 return "Concurrent marking (unload classes)";
2740 } else {
2741 return "Concurrent marking";
2742 }
2743 }
2744
2745 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2746 switch (point) {
2747 case _degenerated_unset:
2748 return "Pause Degenerated GC (<UNSET>)";
2749 case _degenerated_traversal:
2750 return "Pause Degenerated GC (Traversal)";
2751 case _degenerated_outside_cycle:
2752 return "Pause Degenerated GC (Outside of Cycle)";
2753 case _degenerated_mark:
2754 return "Pause Degenerated GC (Mark)";
2755 case _degenerated_evac:
2756 return "Pause Degenerated GC (Evacuation)";
2757 case _degenerated_updaterefs:
2758 return "Pause Degenerated GC (Update Refs)";
2759 default:
2760 ShouldNotReachHere();
2761 return "ERROR";
2762 }
2763 }
2764
2765 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2766 #ifdef ASSERT
2767 assert(worker_id < _max_workers, "sanity");
2768 for (uint i = 0; i < num_regions(); i++) {
2769 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2770 }
2771 #endif
2772 return _liveness_cache[worker_id];
2773 }
2774
2775 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2776 assert(worker_id < _max_workers, "sanity");
2777 jushort* ld = _liveness_cache[worker_id];
2778 for (uint i = 0; i < num_regions(); i++) {
2779 ShenandoahHeapRegion* r = get_region(i);
2780 jushort live = ld[i];
2781 if (live > 0) {
2782 r->increase_live_data_gc_words(live);
2783 ld[i] = 0;
2784 }
2785 }
2786 }
2787
2788 size_t ShenandoahHeap::obj_size(oop obj) const {
2789 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2790 }
2791
2792 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2793 return ShenandoahBrooksPointer::byte_size();
2794 }
2795
2796 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2797 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2798 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2799 }