1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc_implementation/shared/gcTimer.hpp"
28 #include "gc_implementation/shenandoah/shenandoahGCTraceTime.hpp"
29 #include "gc_implementation/shared/parallelCleaning.hpp"
30
31 #include "gc_implementation/shenandoah/shenandoahBrooksPointer.hpp"
32 #include "gc_implementation/shenandoah/shenandoahAllocTracker.hpp"
33 #include "gc_implementation/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.inline.hpp"
37 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp"
38 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp"
39 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
40 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
41 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp"
42 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp"
43 #include "gc_implementation/shenandoah/shenandoahMarkCompact.hpp"
44 #include "gc_implementation/shenandoah/shenandoahMarkingContext.inline.hpp"
45 #include "gc_implementation/shenandoah/shenandoahMonitoringSupport.hpp"
46 #include "gc_implementation/shenandoah/shenandoahMetrics.hpp"
47 #include "gc_implementation/shenandoah/shenandoahOopClosures.inline.hpp"
48 #include "gc_implementation/shenandoah/shenandoahPacer.inline.hpp"
49 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp"
50 #include "gc_implementation/shenandoah/shenandoahUtils.hpp"
51 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp"
52 #include "gc_implementation/shenandoah/shenandoahCodeRoots.hpp"
53 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp"
54 #include "gc_implementation/shenandoah/shenandoahWorkGroup.hpp"
55 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp"
56 #include "gc_implementation/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
57 #include "gc_implementation/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
58 #include "gc_implementation/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
59 #include "gc_implementation/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
60 #include "gc_implementation/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
61
62 #include "memory/metaspace.hpp"
63 #include "runtime/vmThread.hpp"
64 #include "services/mallocTracker.hpp"
65
66 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
67
68 #ifdef ASSERT
69 template <class T>
70 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
71 T o = oopDesc::load_heap_oop(p);
72 if (! oopDesc::is_null(o)) {
73 oop obj = oopDesc::decode_heap_oop_not_null(o);
74 shenandoah_assert_not_forwarded(p, obj);
75 }
76 }
77
78 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
79 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
80 #endif
81
82 class ShenandoahPretouchHeapTask : public AbstractGangTask {
83 private:
84 ShenandoahRegionIterator _regions;
85 const size_t _page_size;
86 public:
87 ShenandoahPretouchHeapTask(size_t page_size) :
88 AbstractGangTask("Shenandoah Pretouch Heap"),
89 _page_size(page_size) {}
90
91 virtual void work(uint worker_id) {
92 ShenandoahHeapRegion* r = _regions.next();
93 while (r != NULL) {
94 os::pretouch_memory((char*) r->bottom(), (char*) r->end());
95 r = _regions.next();
96 }
97 }
98 };
99
100 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
101 private:
102 ShenandoahRegionIterator _regions;
103 char* _bitmap_base;
104 const size_t _bitmap_size;
105 const size_t _page_size;
106 public:
107 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
108 AbstractGangTask("Shenandoah Pretouch Bitmap"),
109 _bitmap_base(bitmap_base),
110 _bitmap_size(bitmap_size),
111 _page_size(page_size) {}
112
113 virtual void work(uint worker_id) {
114 ShenandoahHeapRegion* r = _regions.next();
115 while (r != NULL) {
116 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
117 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
118 assert (end <= _bitmap_size, err_msg("end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size));
119
120 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end);
121
122 r = _regions.next();
123 }
124 }
125 };
126
127 jint ShenandoahHeap::initialize() {
128 CollectedHeap::pre_initialize();
129
130 ShenandoahBrooksPointer::initial_checks();
131
132 initialize_heuristics();
133
134 //
135 // Figure out heap sizing
136 //
137
138 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
139 size_t max_byte_size = collector_policy()->max_heap_byte_size();
140 size_t heap_alignment = collector_policy()->heap_alignment();
141
142 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
143
144 if (ShenandoahAlwaysPreTouch) {
145 // Enabled pre-touch means the entire heap is committed right away.
146 init_byte_size = max_byte_size;
147 }
148
149 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
150 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
151
152 _num_regions = ShenandoahHeapRegion::region_count();
153
154 size_t num_committed_regions = init_byte_size / reg_size_bytes;
155 num_committed_regions = MIN2(num_committed_regions, _num_regions);
156 assert(num_committed_regions <= _num_regions, "sanity");
157
158 _initial_size = num_committed_regions * reg_size_bytes;
159 _committed = _initial_size;
160
161 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
162 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
163
164 //
165 // Reserve and commit memory for heap
166 //
167
168 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
169 _reserved.set_word_size(0);
170 _reserved.set_start((HeapWord*)heap_rs.base());
171 _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size()));
172 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
173 _heap_region_special = heap_rs.special();
174
175 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
176 err_msg("Misaligned heap: " PTR_FORMAT, p2i(base())));
177
178 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
179 if (!_heap_region_special) {
180 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
181 "Cannot commit heap memory");
182 }
183
184 //
185 // Reserve and commit memory for bitmap(s)
186 //
187
188 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
189 _bitmap_size = align_size_up(_bitmap_size, bitmap_page_size);
190
191 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
192
193 guarantee(bitmap_bytes_per_region != 0,
194 err_msg("Bitmap bytes per region should not be zero"));
195 guarantee(is_power_of_2(bitmap_bytes_per_region),
196 err_msg("Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region));
197
198 if (bitmap_page_size > bitmap_bytes_per_region) {
199 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
200 _bitmap_bytes_per_slice = bitmap_page_size;
201 } else {
202 _bitmap_regions_per_slice = 1;
203 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
204 }
205
206 guarantee(_bitmap_regions_per_slice >= 1,
207 err_msg("Should have at least one region per slice: " SIZE_FORMAT,
208 _bitmap_regions_per_slice));
209
210 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
211 err_msg("Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
212 _bitmap_bytes_per_slice, bitmap_page_size));
213
214 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
215 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
216 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
217 _bitmap_region_special = bitmap.special();
218
219 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
220 align_size_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
221 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
222 if (!_bitmap_region_special) {
223 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
224 "Cannot commit bitmap memory");
225 }
226
227 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
228
229 if (ShenandoahVerify) {
230 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
231 if (!verify_bitmap.special()) {
232 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
233 "Cannot commit verification bitmap memory");
234 }
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 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
242 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
243 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
244 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
245 _aux_bitmap_region_special = aux_bitmap.special();
246 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
247
248 //
249 // Create regions and region sets
250 //
251
252 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
253 _free_set = new ShenandoahFreeSet(this, _num_regions);
254 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)sh_rs.base());
255
256 {
257 ShenandoahHeapLocker locker(lock());
258
259 size_t size_words = ShenandoahHeapRegion::region_size_words();
260
261 for (size_t i = 0; i < _num_regions; i++) {
262 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
263 bool is_committed = i < num_committed_regions;
264 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
265
266 _marking_context->initialize_top_at_mark_start(r);
267 _regions[i] = r;
268 assert(!collection_set()->is_in(i), "New region should not be in collection set");
269 }
270
271 // Initialize to complete
272 _marking_context->mark_complete();
273
274 _free_set->rebuild();
275 }
276
277 if (ShenandoahAlwaysPreTouch) {
278 assert(!AlwaysPreTouch, "Should have been overridden");
279
280 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
281 // before initialize() below zeroes it with initializing thread. For any given region,
282 // we touch the region and the corresponding bitmaps from the same thread.
283 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
284
285 size_t pretouch_heap_page_size = heap_page_size;
286 size_t pretouch_bitmap_page_size = bitmap_page_size;
287
288 #ifdef LINUX
289 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
290 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
291 // them into huge one. Therefore, we need to pretouch with smaller pages.
292 if (UseTransparentHugePages) {
293 pretouch_heap_page_size = (size_t)os::vm_page_size();
294 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
295 }
296 #endif
297
298 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
299 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
300
301 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
302 _num_regions, pretouch_bitmap_page_size);
303 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
304 _workers->run_task(&bcl);
305
306 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
307 _num_regions, pretouch_heap_page_size);
308 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
309 _workers->run_task(&hcl);
310 }
311
312 //
313 // Initialize the rest of GC subsystems
314 //
315
316 set_barrier_set(new ShenandoahBarrierSet(this));
317
318 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
319 for (uint worker = 0; worker < _max_workers; worker++) {
320 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
321 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
322 }
323
324 // The call below uses stuff (the SATB* things) that are in G1, but probably
325 // belong into a shared location.
326 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
327 SATB_Q_FL_lock,
328 20 /*G1SATBProcessCompletedThreshold */,
329 Shared_SATB_Q_lock);
330
331 _monitoring_support = new ShenandoahMonitoringSupport(this);
332 _phase_timings = new ShenandoahPhaseTimings();
333 ShenandoahStringDedup::initialize();
334 ShenandoahCodeRoots::initialize();
335
336 if (ShenandoahAllocationTrace) {
337 _alloc_tracker = new ShenandoahAllocTracker();
338 }
339
340 if (ShenandoahPacing) {
341 _pacer = new ShenandoahPacer(this);
342 _pacer->setup_for_idle();
343 } else {
344 _pacer = NULL;
345 }
346
347 _control_thread = new ShenandoahControlThread();
348
349 log_info(gc, init)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
350 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
351
352 return JNI_OK;
353 }
354
355 #ifdef _MSC_VER
356 #pragma warning( push )
357 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
358 #endif
359
360 void ShenandoahHeap::initialize_heuristics() {
361 if (ShenandoahGCHeuristics != NULL) {
362 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
363 _heuristics = new ShenandoahAggressiveHeuristics();
364 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
365 _heuristics = new ShenandoahStaticHeuristics();
366 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
367 _heuristics = new ShenandoahAdaptiveHeuristics();
368 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
369 _heuristics = new ShenandoahPassiveHeuristics();
370 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
371 _heuristics = new ShenandoahCompactHeuristics();
372 } else {
373 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
374 }
375
376 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
377 vm_exit_during_initialization(
378 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
379 _heuristics->name()));
380 }
381 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
382 vm_exit_during_initialization(
383 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
384 _heuristics->name()));
385 }
386 log_info(gc, init)("Shenandoah heuristics: %s",
387 _heuristics->name());
388 } else {
389 ShouldNotReachHere();
390 }
391 }
392
393 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
394 SharedHeap(policy),
395 _shenandoah_policy(policy),
396 _heap_region_special(false),
397 _regions(NULL),
398 _free_set(NULL),
399 _collection_set(NULL),
400 _update_refs_iterator(this),
401 _bytes_allocated_since_gc_start(0),
402 _max_workers((uint)MAX2(ConcGCThreads, ParallelGCThreads)),
403 _ref_processor(NULL),
404 _marking_context(NULL),
405 _bitmap_size(0),
406 _bitmap_regions_per_slice(0),
407 _bitmap_bytes_per_slice(0),
408 _bitmap_region_special(false),
409 _aux_bitmap_region_special(false),
410 _liveness_cache(NULL),
411 _aux_bit_map(),
412 _verifier(NULL),
413 _pacer(NULL),
414 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
415 _phase_timings(NULL),
416 _alloc_tracker(NULL)
417 {
418 log_info(gc, init)("GC threads: " UINTX_FORMAT " parallel, " UINTX_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
419 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
420
421 _scm = new ShenandoahConcurrentMark();
422 _full_gc = new ShenandoahMarkCompact();
423 _used = 0;
424
425 _max_workers = MAX2(_max_workers, 1U);
426 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
427 /* are_GC_task_threads */true,
428 /* are_ConcurrentGC_threads */false);
429 if (_workers == NULL) {
430 vm_exit_during_initialization("Failed necessary allocation.");
431 } else {
432 _workers->initialize_workers();
433 }
434 }
435
436 #ifdef _MSC_VER
437 #pragma warning( pop )
438 #endif
439
440 class ShenandoahResetBitmapTask : public AbstractGangTask {
441 private:
442 ShenandoahRegionIterator _regions;
443
444 public:
445 ShenandoahResetBitmapTask() :
446 AbstractGangTask("Parallel Reset Bitmap Task") {}
447
448 void work(uint worker_id) {
449 ShenandoahHeapRegion* region = _regions.next();
450 ShenandoahHeap* heap = ShenandoahHeap::heap();
451 ShenandoahMarkingContext* const ctx = heap->marking_context();
452 while (region != NULL) {
453 if (heap->is_bitmap_slice_committed(region)) {
454 ctx->clear_bitmap(region);
455 }
456 region = _regions.next();
457 }
458 }
459 };
460
461 void ShenandoahHeap::reset_mark_bitmap() {
462 assert_gc_workers(_workers->active_workers());
463 mark_incomplete_marking_context();
464
465 ShenandoahResetBitmapTask task;
466 _workers->run_task(&task);
467 }
468
469 void ShenandoahHeap::print_on(outputStream* st) const {
470 st->print_cr("Shenandoah Heap");
471 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
472 capacity() / K, committed() / K, used() / K);
473 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
474 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
475
476 st->print("Status: ");
477 if (has_forwarded_objects()) st->print("has forwarded objects, ");
478 if (is_concurrent_mark_in_progress()) st->print("marking, ");
479 if (is_evacuation_in_progress()) st->print("evacuating, ");
480 if (is_update_refs_in_progress()) st->print("updating refs, ");
481 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
482 if (is_full_gc_in_progress()) st->print("full gc, ");
483 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
484
485 if (cancelled_gc()) {
486 st->print("cancelled");
487 } else {
488 st->print("not cancelled");
489 }
490 st->cr();
491
492 st->print_cr("Reserved region:");
493 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
494 p2i(reserved_region().start()),
495 p2i(reserved_region().end()));
496
497 st->cr();
498 MetaspaceAux::print_on(st);
499
500 if (Verbose) {
501 print_heap_regions_on(st);
502 }
503 }
504
505 class ShenandoahInitGCLABClosure : public ThreadClosure {
506 public:
507 void do_thread(Thread* thread) {
508 assert(thread == NULL || !thread->is_Java_thread(), "Don't expect JavaThread this early");
509 if (thread != NULL && thread->is_Worker_thread()) {
510 thread->gclab().initialize(true);
511 }
512 }
513 };
514
515 void ShenandoahHeap::post_initialize() {
516 if (UseTLAB) {
517 MutexLocker ml(Threads_lock);
518
519 ShenandoahInitGCLABClosure init_gclabs;
520 Threads::threads_do(&init_gclabs);
521 }
522
523 _scm->initialize(_max_workers);
524 _full_gc->initialize(_gc_timer);
525
526 ref_processing_init();
527
528 _heuristics->initialize();
529 }
530
531 size_t ShenandoahHeap::used() const {
532 OrderAccess::acquire();
533 return (size_t) _used;
534 }
535
536 size_t ShenandoahHeap::committed() const {
537 OrderAccess::acquire();
538 return _committed;
539 }
540
541 void ShenandoahHeap::increase_committed(size_t bytes) {
542 assert_heaplock_or_safepoint();
543 _committed += bytes;
544 }
545
546 void ShenandoahHeap::decrease_committed(size_t bytes) {
547 assert_heaplock_or_safepoint();
548 _committed -= bytes;
549 }
550
551 void ShenandoahHeap::increase_used(size_t bytes) {
552 Atomic::add(bytes, &_used);
553 }
554
555 void ShenandoahHeap::set_used(size_t bytes) {
556 OrderAccess::release_store_fence(&_used, bytes);
557 }
558
559 void ShenandoahHeap::decrease_used(size_t bytes) {
560 assert(used() >= bytes, "never decrease heap size by more than we've left");
561 Atomic::add(-(jlong)bytes, &_used);
562 }
563
564 void ShenandoahHeap::increase_allocated(size_t bytes) {
565 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
566 }
567
568 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
569 size_t bytes = words * HeapWordSize;
570 if (!waste) {
571 increase_used(bytes);
572 }
573 increase_allocated(bytes);
574 if (ShenandoahPacing) {
575 control_thread()->pacing_notify_alloc(words);
576 if (waste) {
577 pacer()->claim_for_alloc(words, true);
578 }
579 }
580 }
581
582 size_t ShenandoahHeap::capacity() const {
583 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
584 }
585
586 size_t ShenandoahHeap::max_capacity() const {
587 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
588 }
589
590 size_t ShenandoahHeap::initial_capacity() const {
591 return _initial_size;
592 }
593
594 bool ShenandoahHeap::is_in(const void* p) const {
595 HeapWord* heap_base = (HeapWord*) base();
596 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
597 return p >= heap_base && p < last_region_end;
598 }
599
600 void ShenandoahHeap::op_uncommit(double shrink_before) {
601 assert (ShenandoahUncommit, "should be enabled");
602
603 size_t count = 0;
604 for (size_t i = 0; i < num_regions(); i++) {
605 ShenandoahHeapRegion* r = get_region(i);
606 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
607 ShenandoahHeapLocker locker(lock());
608 if (r->is_empty_committed()) {
609 r->make_uncommitted();
610 count++;
611 }
612 }
613 SpinPause(); // allow allocators to take the lock
614 }
615
616 if (count > 0) {
617 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
618 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
619 _control_thread->notify_heap_changed();
620 }
621 }
622
623 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
624 // Retain tlab and allocate object in shared space if
625 // the amount free in the tlab is too large to discard.
626 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
627 thread->gclab().record_slow_allocation(size);
628 return NULL;
629 }
630
631 // Discard gclab and allocate a new one.
632 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
633 size_t new_gclab_size = thread->gclab().compute_size(size);
634
635 thread->gclab().clear_before_allocation();
636
637 if (new_gclab_size == 0) {
638 return NULL;
639 }
640
641 // Allocated object should fit in new GCLAB, and new_gclab_size should be larger than min
642 size_t min_size = MAX2(size + ThreadLocalAllocBuffer::alignment_reserve(), ThreadLocalAllocBuffer::min_size());
643 new_gclab_size = MAX2(new_gclab_size, min_size);
644
645 // Allocate a new GCLAB...
646 size_t actual_size = 0;
647 HeapWord* obj = allocate_new_gclab(min_size, new_gclab_size, &actual_size);
648
649 if (obj == NULL) {
650 return NULL;
651 }
652
653 assert (size <= actual_size, "allocation should fit");
654
655 if (ZeroTLAB) {
656 // ..and clear it.
657 Copy::zero_to_words(obj, actual_size);
658 } else {
659 // ...and zap just allocated object.
660 #ifdef ASSERT
661 // Skip mangling the space corresponding to the object header to
662 // ensure that the returned space is not considered parsable by
663 // any concurrent GC thread.
664 size_t hdr_size = oopDesc::header_size();
665 Copy::fill_to_words(obj + hdr_size, actual_size - hdr_size, badHeapWordVal);
666 #endif // ASSERT
667 }
668 thread->gclab().fill(obj, obj + size, actual_size);
669 return obj;
670 }
671
672 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
673 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(word_size);
674 return allocate_memory(req);
675 }
676
677 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
678 size_t word_size,
679 size_t* actual_size) {
680 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
681 HeapWord* res = allocate_memory(req);
682 if (res != NULL) {
683 *actual_size = req.actual_size();
684 } else {
685 *actual_size = 0;
686 }
687 return res;
688 }
689
690 ShenandoahHeap* ShenandoahHeap::heap() {
691 CollectedHeap* heap = Universe::heap();
692 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
693 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
694 return (ShenandoahHeap*) heap;
695 }
696
697 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
698 CollectedHeap* heap = Universe::heap();
699 return (ShenandoahHeap*) heap;
700 }
701
702 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
703 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
704
705 intptr_t pacer_epoch = 0;
706 bool in_new_region = false;
707 HeapWord* result = NULL;
708
709 if (req.is_mutator_alloc()) {
710 if (ShenandoahPacing) {
711 pacer()->pace_for_alloc(req.size());
712 pacer_epoch = pacer()->epoch();
713 }
714
715 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
716 result = allocate_memory_under_lock(req, in_new_region);
717 }
718
719 // Allocation failed, block until control thread reacted, then retry allocation.
720 //
721 // It might happen that one of the threads requesting allocation would unblock
722 // way later after GC happened, only to fail the second allocation, because
723 // other threads have already depleted the free storage. In this case, a better
724 // strategy is to try again, as long as GC makes progress.
725 //
726 // Then, we need to make sure the allocation was retried after at least one
727 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
728
729 size_t tries = 0;
730
731 while (result == NULL && _progress_last_gc.is_set()) {
732 tries++;
733 control_thread()->handle_alloc_failure(req.size());
734 result = allocate_memory_under_lock(req, in_new_region);
735 }
736
737 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
738 tries++;
739 control_thread()->handle_alloc_failure(req.size());
740 result = allocate_memory_under_lock(req, in_new_region);
741 }
742
743 } else {
744 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
745 result = allocate_memory_under_lock(req, in_new_region);
746 // Do not call handle_alloc_failure() here, because we cannot block.
747 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
748 }
749
750 if (in_new_region) {
751 control_thread()->notify_heap_changed();
752 }
753
754 if (result != NULL) {
755 size_t requested = req.size();
756 size_t actual = req.actual_size();
757
758 assert (req.is_lab_alloc() || (requested == actual),
759 err_msg("Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
760 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual));
761
762 if (req.is_mutator_alloc()) {
763 notify_mutator_alloc_words(actual, false);
764
765 // If we requested more than we were granted, give the rest back to pacer.
766 // This only matters if we are in the same pacing epoch: do not try to unpace
767 // over the budget for the other phase.
768 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
769 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
770 }
771 } else {
772 increase_used(actual*HeapWordSize);
773 }
774 }
775
776 return result;
777 }
778
779 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
780 ShenandoahHeapLocker locker(lock());
781 return _free_set->allocate(req, in_new_region);
782 }
783
784 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
785 bool* gc_overhead_limit_was_exceeded) {
786 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size + ShenandoahBrooksPointer::word_size());
787 HeapWord* filler = allocate_memory(req);
788 HeapWord* result = filler + ShenandoahBrooksPointer::word_size();
789 if (filler != NULL) {
790 ShenandoahBrooksPointer::initialize(oop(result));
791
792 assert(! in_collection_set(result), "never allocate in targetted region");
793 return result;
794 } else {
795 return NULL;
796 }
797 }
798
799 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
800 private:
801 ShenandoahHeap* _heap;
802 Thread* _thread;
803 public:
804 ShenandoahEvacuateUpdateRootsClosure() :
805 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
806 }
807
808 private:
809 template <class T>
810 void do_oop_work(T* p) {
811 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
812
813 T o = oopDesc::load_heap_oop(p);
814 if (! oopDesc::is_null(o)) {
815 oop obj = oopDesc::decode_heap_oop_not_null(o);
816 if (_heap->in_collection_set(obj)) {
817 shenandoah_assert_marked(p, obj);
818 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
819 if (oopDesc::unsafe_equals(resolved, obj)) {
820 bool evac;
821 resolved = _heap->evacuate_object(obj, _thread, evac);
822 }
823 oopDesc::encode_store_heap_oop(p, resolved);
824 }
825 }
826 }
827
828 public:
829 void do_oop(oop* p) {
830 do_oop_work(p);
831 }
832 void do_oop(narrowOop* p) {
833 do_oop_work(p);
834 }
835 };
836
837 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
838 private:
839 ShenandoahHeap* const _heap;
840 Thread* const _thread;
841 public:
842 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
843 _heap(heap), _thread(Thread::current()) {}
844
845 void do_object(oop p) {
846 shenandoah_assert_marked(NULL, p);
847 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
848 bool evac;
849 _heap->evacuate_object(p, _thread, evac);
850 }
851 }
852 };
853
854 class ShenandoahEvacuationTask : public AbstractGangTask {
855 private:
856 ShenandoahHeap* const _sh;
857 ShenandoahCollectionSet* const _cs;
858 bool _concurrent;
859 public:
860 ShenandoahEvacuationTask(ShenandoahHeap* sh,
861 ShenandoahCollectionSet* cs,
862 bool concurrent) :
863 AbstractGangTask("Parallel Evacuation Task"),
864 _sh(sh),
865 _cs(cs),
866 _concurrent(concurrent)
867 {}
868
869 void work(uint worker_id) {
870 ShenandoahEvacOOMScope oom_evac_scope;
871 if (_concurrent) {
872 ShenandoahConcurrentWorkerSession worker_session(worker_id);
873 do_work();
874 } else {
875 ShenandoahParallelWorkerSession worker_session(worker_id);
876 do_work();
877 }
878 }
879
880 private:
881 void do_work() {
882 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
883 ShenandoahHeapRegion* r;
884 while ((r =_cs->claim_next()) != NULL) {
885 assert(r->has_live(), "all-garbage regions are reclaimed early");
886 _sh->marked_object_iterate(r, &cl);
887
888 if (ShenandoahPacing) {
889 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
890 }
891
892 if (_sh->cancelled_gc()) {
893 break;
894 }
895 }
896 }
897 };
898
899 void ShenandoahHeap::trash_cset_regions() {
900 ShenandoahHeapLocker locker(lock());
901
902 ShenandoahCollectionSet* set = collection_set();
903 ShenandoahHeapRegion* r;
904 set->clear_current_index();
905 while ((r = set->next()) != NULL) {
906 r->make_trash();
907 }
908 collection_set()->clear();
909 }
910
911 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
912 st->print_cr("Heap Regions:");
913 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
914 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
915 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
916
917 for (size_t i = 0; i < num_regions(); i++) {
918 get_region(i)->print_on(st);
919 }
920 }
921
922 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
923 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
924
925 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
926 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
927 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
928 size_t index = start->region_number() + required_regions - 1;
929
930 assert(!start->has_live(), "liveness must be zero");
931
932 for(size_t i = 0; i < required_regions; i++) {
933 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
934 // as it expects that every region belongs to a humongous region starting with a humongous start region.
935 ShenandoahHeapRegion* region = get_region(index --);
936
937 assert(region->is_humongous(), "expect correct humongous start or continuation");
938 assert(!region->is_cset(), "Humongous region should not be in collection set");
939
940 region->make_trash_immediate();
941 }
942 }
943
944 class ShenandoahRetireGCLABClosure : public ThreadClosure {
945 private:
946 bool _retire;
947 public:
948 ShenandoahRetireGCLABClosure(bool retire) : _retire(retire) {};
949
950 void do_thread(Thread* thread) {
951 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
952 thread->gclab().make_parsable(_retire);
953 }
954 };
955
956 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
957 if (UseTLAB) {
958 CollectedHeap::ensure_parsability(retire_tlabs);
959 ShenandoahRetireGCLABClosure cl(retire_tlabs);
960 Threads::java_threads_do(&cl);
961 _workers->threads_do(&cl);
962 }
963 }
964
965 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
966 private:
967 ShenandoahRootEvacuator* _rp;
968
969 public:
970 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
971 AbstractGangTask("Shenandoah evacuate and update roots"),
972 _rp(rp) {}
973
974 void work(uint worker_id) {
975 ShenandoahParallelWorkerSession worker_session(worker_id);
976 ShenandoahEvacOOMScope oom_evac_scope;
977 ShenandoahEvacuateUpdateRootsClosure cl;
978
979 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
980 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
981 }
982 };
983
984 void ShenandoahHeap::evacuate_and_update_roots() {
985 COMPILER2_PRESENT(DerivedPointerTable::clear());
986
987 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
988
989 {
990 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
991 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
992 workers()->run_task(&roots_task);
993 }
994
995 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
996 }
997
998 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
999 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1000
1001 CodeBlobToOopClosure blobsCl(cl, false);
1002 CLDToOopClosure cldCl(cl);
1003
1004 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1005 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1006 }
1007
1008 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1009 // Returns size in bytes
1010 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1011 }
1012
1013 size_t ShenandoahHeap::max_tlab_size() const {
1014 // Returns size in words
1015 return ShenandoahHeapRegion::max_tlab_size_words();
1016 }
1017
1018 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1019 public:
1020 void do_thread(Thread* thread) {
1021 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
1022 thread->gclab().resize();
1023 }
1024 };
1025
1026 void ShenandoahHeap::resize_all_tlabs() {
1027 CollectedHeap::resize_all_tlabs();
1028
1029 ShenandoahResizeGCLABClosure cl;
1030 Threads::java_threads_do(&cl);
1031 _workers->threads_do(&cl);
1032 }
1033
1034 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1035 public:
1036 void do_thread(Thread* thread) {
1037 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name()));
1038 thread->gclab().accumulate_statistics();
1039 thread->gclab().initialize_statistics();
1040 }
1041 };
1042
1043 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1044 ShenandoahAccumulateStatisticsGCLABClosure cl;
1045 Threads::java_threads_do(&cl);
1046 _workers->threads_do(&cl);
1047 }
1048
1049 void ShenandoahHeap::collect(GCCause::Cause cause) {
1050 _control_thread->request_gc(cause);
1051 }
1052
1053 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1054 //assert(false, "Shouldn't need to do full collections");
1055 }
1056
1057 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1058 return _shenandoah_policy;
1059 }
1060
1061 void ShenandoahHeap::resize_tlabs() {
1062 CollectedHeap::resize_all_tlabs();
1063 }
1064
1065 void ShenandoahHeap::accumulate_statistics_tlabs() {
1066 CollectedHeap::accumulate_statistics_all_tlabs();
1067 }
1068
1069 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1070 Space* sp = heap_region_containing(addr);
1071 if (sp != NULL) {
1072 return sp->block_start(addr);
1073 }
1074 return NULL;
1075 }
1076
1077 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1078 Space* sp = heap_region_containing(addr);
1079 assert(sp != NULL, "block_size of address outside of heap");
1080 return sp->block_size(addr);
1081 }
1082
1083 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1084 Space* sp = heap_region_containing(addr);
1085 return sp->block_is_obj(addr);
1086 }
1087
1088 jlong ShenandoahHeap::millis_since_last_gc() {
1089 double v = heuristics()->time_since_last_gc() * 1000;
1090 assert(0 <= v && v <= max_jlong, err_msg("value should fit: %f", v));
1091 return (jlong)v;
1092 }
1093
1094 void ShenandoahHeap::prepare_for_verify() {
1095 if (SafepointSynchronize::is_at_safepoint()) {
1096 make_parsable(false);
1097 }
1098 }
1099
1100 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1101 workers()->print_worker_threads_on(st);
1102 if (ShenandoahStringDedup::is_enabled()) {
1103 ShenandoahStringDedup::print_worker_threads_on(st);
1104 }
1105 }
1106
1107 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1108 workers()->threads_do(tcl);
1109 if (ShenandoahStringDedup::is_enabled()) {
1110 ShenandoahStringDedup::threads_do(tcl);
1111 }
1112 }
1113
1114 void ShenandoahHeap::print_tracing_info() const {
1115 if (PrintGC || TraceGen0Time || TraceGen1Time) {
1116 ResourceMark rm;
1117 outputStream* out = gclog_or_tty;
1118 phase_timings()->print_on(out);
1119
1120 out->cr();
1121 out->cr();
1122
1123 shenandoah_policy()->print_gc_stats(out);
1124
1125 out->cr();
1126 out->cr();
1127
1128 if (ShenandoahPacing) {
1129 pacer()->print_on(out);
1130 }
1131
1132 out->cr();
1133 out->cr();
1134
1135 if (ShenandoahAllocationTrace) {
1136 assert(alloc_tracker() != NULL, "Must be");
1137 alloc_tracker()->print_on(out);
1138 } else {
1139 out->print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1140 }
1141 }
1142 }
1143
1144 void ShenandoahHeap::verify(bool silent, VerifyOption vo) {
1145 if (ShenandoahSafepoint::is_at_shenandoah_safepoint() || ! UseTLAB) {
1146 if (ShenandoahVerify) {
1147 verifier()->verify_generic(vo);
1148 } else {
1149 // TODO: Consider allocating verification bitmaps on demand,
1150 // and turn this on unconditionally.
1151 }
1152 }
1153 }
1154 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1155 return _free_set->capacity();
1156 }
1157
1158 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1159 private:
1160 MarkBitMap* _bitmap;
1161 Stack<oop,mtGC>* _oop_stack;
1162
1163 template <class T>
1164 void do_oop_work(T* p) {
1165 T o = oopDesc::load_heap_oop(p);
1166 if (!oopDesc::is_null(o)) {
1167 oop obj = oopDesc::decode_heap_oop_not_null(o);
1168 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1169 assert(obj->is_oop(), "must be a valid oop");
1170 if (!_bitmap->isMarked((HeapWord*) obj)) {
1171 _bitmap->mark((HeapWord*) obj);
1172 _oop_stack->push(obj);
1173 }
1174 }
1175 }
1176 public:
1177 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1178 _bitmap(bitmap), _oop_stack(oop_stack) {}
1179 void do_oop(oop* p) { do_oop_work(p); }
1180 void do_oop(narrowOop* p) { do_oop_work(p); }
1181 };
1182
1183 /*
1184 * This is public API, used in preparation of object_iterate().
1185 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1186 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1187 * control, we call SH::make_parsable().
1188 */
1189 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1190 // No-op.
1191 }
1192
1193 /*
1194 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1195 *
1196 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1197 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1198 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1199 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1200 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1201 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1202 * wiped the bitmap in preparation for next marking).
1203 *
1204 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1205 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1206 * is allowed to report dead objects, but is not required to do so.
1207 */
1208 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1209 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1210 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1211 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1212 return;
1213 }
1214
1215 // Reset bitmap
1216 _aux_bit_map.clear();
1217
1218 Stack<oop,mtGC> oop_stack;
1219
1220 // First, we process all GC roots. This populates the work stack with initial objects.
1221 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1222 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1223 CLDToOopClosure clds(&oops, false);
1224 CodeBlobToOopClosure blobs(&oops, false);
1225 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1226
1227 // Work through the oop stack to traverse heap.
1228 while (! oop_stack.is_empty()) {
1229 oop obj = oop_stack.pop();
1230 assert(obj->is_oop(), "must be a valid oop");
1231 cl->do_object(obj);
1232 obj->oop_iterate(&oops);
1233 }
1234
1235 assert(oop_stack.is_empty(), "should be empty");
1236
1237 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1238 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1239 }
1240 }
1241
1242 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1243 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1244 object_iterate(cl);
1245 }
1246
1247 void ShenandoahHeap::oop_iterate(ExtendedOopClosure* cl) {
1248 ObjectToOopClosure cl2(cl);
1249 object_iterate(&cl2);
1250 }
1251
1252 class ShenandoahSpaceClosureRegionClosure: public ShenandoahHeapRegionClosure {
1253 SpaceClosure* _cl;
1254 public:
1255 ShenandoahSpaceClosureRegionClosure(SpaceClosure* cl) : _cl(cl) {}
1256 void heap_region_do(ShenandoahHeapRegion* r) {
1257 _cl->do_space(r);
1258 }
1259 };
1260
1261 void ShenandoahHeap::space_iterate(SpaceClosure* cl) {
1262 ShenandoahSpaceClosureRegionClosure blk(cl);
1263 heap_region_iterate(&blk);
1264 }
1265
1266 Space* ShenandoahHeap::space_containing(const void* oop) const {
1267 Space* res = heap_region_containing(oop);
1268 return res;
1269 }
1270
1271 void ShenandoahHeap::gc_prologue(bool b) {
1272 Unimplemented();
1273 }
1274
1275 void ShenandoahHeap::gc_epilogue(bool b) {
1276 Unimplemented();
1277 }
1278
1279 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1280 for (size_t i = 0; i < num_regions(); i++) {
1281 ShenandoahHeapRegion* current = get_region(i);
1282 blk->heap_region_do(current);
1283 }
1284 }
1285
1286 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1287 private:
1288 ShenandoahHeap* const _heap;
1289 ShenandoahHeapRegionClosure* const _blk;
1290
1291 char _pad0[DEFAULT_CACHE_LINE_SIZE];
1292 volatile jint _index;
1293 char _pad1[DEFAULT_CACHE_LINE_SIZE];
1294
1295 public:
1296 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1297 AbstractGangTask("Parallel Region Task"),
1298 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1299
1300 void work(uint worker_id) {
1301 jint stride = (jint)ShenandoahParallelRegionStride;
1302
1303 jint max = (jint)_heap->num_regions();
1304 while (_index < max) {
1305 jint cur = Atomic::add(stride, &_index) - stride;
1306 jint start = cur;
1307 jint end = MIN2(cur + stride, max);
1308 if (start >= max) break;
1309
1310 for (jint i = cur; i < end; i++) {
1311 ShenandoahHeapRegion* current = _heap->get_region((size_t)i);
1312 _blk->heap_region_do(current);
1313 }
1314 }
1315 }
1316 };
1317
1318 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1319 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1320 if (num_regions() > ShenandoahParallelRegionStride) {
1321 ShenandoahParallelHeapRegionTask task(blk);
1322 workers()->run_task(&task);
1323 } else {
1324 heap_region_iterate(blk);
1325 }
1326 }
1327
1328 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1329 private:
1330 ShenandoahMarkingContext* const _ctx;
1331 public:
1332 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1333
1334 void heap_region_do(ShenandoahHeapRegion* r) {
1335 if (r->is_active()) {
1336 r->clear_live_data();
1337 _ctx->capture_top_at_mark_start(r);
1338 } else {
1339 assert(!r->has_live(),
1340 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number()));
1341 assert(_ctx->top_at_mark_start(r) == r->top(),
1342 err_msg("Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()));
1343 }
1344 }
1345
1346 bool is_thread_safe() { return true; }
1347 };
1348
1349 void ShenandoahHeap::op_init_mark() {
1350 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1351 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1352
1353 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1354 assert(!marking_context()->is_complete(), "should not be complete");
1355
1356 if (ShenandoahVerify) {
1357 verifier()->verify_before_concmark();
1358 }
1359
1360 {
1361 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1362 accumulate_statistics_tlabs();
1363 }
1364
1365 if (VerifyBeforeGC) {
1366 Universe::verify();
1367 }
1368
1369 set_concurrent_mark_in_progress(true);
1370 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1371 if (UseTLAB) {
1372 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1373 make_parsable(true);
1374 }
1375
1376 {
1377 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1378 ShenandoahClearLivenessClosure clc;
1379 parallel_heap_region_iterate(&clc);
1380 }
1381
1382 // Make above changes visible to worker threads
1383 OrderAccess::fence();
1384
1385 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1386
1387 if (UseTLAB) {
1388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1389 resize_tlabs();
1390 }
1391
1392 if (ShenandoahPacing) {
1393 pacer()->setup_for_mark();
1394 }
1395 }
1396
1397 void ShenandoahHeap::op_mark() {
1398 concurrent_mark()->mark_from_roots();
1399 }
1400
1401 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1402 private:
1403 ShenandoahMarkingContext* const _ctx;
1404 public:
1405 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1406
1407 void heap_region_do(ShenandoahHeapRegion* r) {
1408 if (r->is_active()) {
1409 HeapWord *tams = _ctx->top_at_mark_start(r);
1410 HeapWord *top = r->top();
1411 if (top > tams) {
1412 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1413 }
1414 } else {
1415 assert(!r->has_live(),
1416 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number()));
1417 assert(_ctx->top_at_mark_start(r) == r->top(),
1418 err_msg("Region " SIZE_FORMAT " should have correct TAMS", r->region_number()));
1419 }
1420 }
1421
1422 bool is_thread_safe() { return true; }
1423 };
1424
1425 void ShenandoahHeap::op_final_mark() {
1426 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1427
1428 // It is critical that we
1429 // evacuate roots right after finishing marking, so that we don't
1430 // get unmarked objects in the roots.
1431
1432 if (!cancelled_gc()) {
1433 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1434
1435 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->reset_taskqueue_stats());
1436
1437 if (has_forwarded_objects()) {
1438 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1439 }
1440
1441 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->print_taskqueue_stats());
1442
1443 stop_concurrent_marking();
1444
1445 {
1446 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1447
1448 // All allocations past TAMS are implicitly live, adjust the region data.
1449 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1450 ShenandoahCompleteLivenessClosure cl;
1451 parallel_heap_region_iterate(&cl);
1452 }
1453
1454 {
1455 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1456
1457 make_parsable(true);
1458
1459 trash_cset_regions();
1460
1461 {
1462 ShenandoahHeapLocker locker(lock());
1463 _collection_set->clear();
1464 _free_set->clear();
1465
1466 heuristics()->choose_collection_set(_collection_set);
1467 _free_set->rebuild();
1468 }
1469 }
1470
1471 // If collection set has candidates, start evacuation.
1472 // Otherwise, bypass the rest of the cycle.
1473 if (!collection_set()->is_empty()) {
1474 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1475
1476 if (ShenandoahVerify) {
1477 verifier()->verify_before_evacuation();
1478 }
1479
1480 set_evacuation_in_progress(true);
1481 // From here on, we need to update references.
1482 set_has_forwarded_objects(true);
1483
1484 evacuate_and_update_roots();
1485
1486 if (ShenandoahPacing) {
1487 pacer()->setup_for_evac();
1488 }
1489 } else {
1490 if (ShenandoahVerify) {
1491 verifier()->verify_after_concmark();
1492 }
1493
1494 if (VerifyAfterGC) {
1495 Universe::verify();
1496 }
1497 }
1498
1499 } else {
1500 concurrent_mark()->cancel();
1501 stop_concurrent_marking();
1502
1503 if (process_references()) {
1504 // Abandon reference processing right away: pre-cleaning must have failed.
1505 ReferenceProcessor *rp = ref_processor();
1506 rp->disable_discovery();
1507 rp->abandon_partial_discovery();
1508 rp->verify_no_references_recorded();
1509 }
1510 }
1511 }
1512
1513 void ShenandoahHeap::op_final_evac() {
1514 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1515
1516 set_evacuation_in_progress(false);
1517 if (ShenandoahVerify) {
1518 verifier()->verify_after_evacuation();
1519 }
1520
1521 if (VerifyAfterGC) {
1522 Universe::verify();
1523 }
1524 }
1525
1526 void ShenandoahHeap::op_conc_evac() {
1527 ShenandoahEvacuationTask task(this, _collection_set, true);
1528 workers()->run_task(&task);
1529 }
1530
1531 void ShenandoahHeap::op_stw_evac() {
1532 ShenandoahEvacuationTask task(this, _collection_set, false);
1533 workers()->run_task(&task);
1534 }
1535
1536 void ShenandoahHeap::op_updaterefs() {
1537 update_heap_references(true);
1538 }
1539
1540 void ShenandoahHeap::op_cleanup() {
1541 free_set()->recycle_trash();
1542 }
1543
1544 void ShenandoahHeap::op_reset() {
1545 reset_mark_bitmap();
1546 }
1547
1548 void ShenandoahHeap::op_preclean() {
1549 concurrent_mark()->preclean_weak_refs();
1550 }
1551
1552 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1553 ShenandoahMetricsSnapshot metrics;
1554 metrics.snap_before();
1555
1556 full_gc()->do_it(cause);
1557
1558 metrics.snap_after();
1559 metrics.print();
1560
1561 if (metrics.is_good_progress("Full GC")) {
1562 _progress_last_gc.set();
1563 } else {
1564 // Nothing to do. Tell the allocation path that we have failed to make
1565 // progress, and it can finally fail.
1566 _progress_last_gc.unset();
1567 }
1568 }
1569
1570 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1571 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1572 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1573 // some phase, we have to upgrade the Degenerate GC to Full GC.
1574
1575 clear_cancelled_gc();
1576
1577 ShenandoahMetricsSnapshot metrics;
1578 metrics.snap_before();
1579
1580 switch (point) {
1581 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1582 // but enters it at different points, depending on which concurrent phase had
1583 // degenerated.
1584
1585 case _degenerated_outside_cycle:
1586 // We have degenerated from outside the cycle, which means something is bad with
1587 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1588 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1589 // we can do the most aggressive degen cycle, which includes processing references and
1590 // class unloading, unless those features are explicitly disabled.
1591 //
1592 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1593 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1594 set_process_references(heuristics()->can_process_references());
1595 set_unload_classes(heuristics()->can_unload_classes());
1596
1597 op_reset();
1598
1599 op_init_mark();
1600 if (cancelled_gc()) {
1601 op_degenerated_fail();
1602 return;
1603 }
1604
1605 case _degenerated_mark:
1606 op_final_mark();
1607 if (cancelled_gc()) {
1608 op_degenerated_fail();
1609 return;
1610 }
1611
1612 op_cleanup();
1613
1614 case _degenerated_evac:
1615 // If heuristics thinks we should do the cycle, this flag would be set,
1616 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1617 if (is_evacuation_in_progress()) {
1618
1619 // Degeneration under oom-evac protocol might have left some objects in
1620 // collection set un-evacuated. Restart evacuation from the beginning to
1621 // capture all objects. For all the objects that are already evacuated,
1622 // it would be a simple check, which is supposed to be fast. This is also
1623 // safe to do even without degeneration, as CSet iterator is at beginning
1624 // in preparation for evacuation anyway.
1625 collection_set()->clear_current_index();
1626
1627 op_stw_evac();
1628 if (cancelled_gc()) {
1629 op_degenerated_fail();
1630 return;
1631 }
1632 }
1633
1634 // If heuristics thinks we should do the cycle, this flag would be set,
1635 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1636 if (has_forwarded_objects()) {
1637 op_init_updaterefs();
1638 if (cancelled_gc()) {
1639 op_degenerated_fail();
1640 return;
1641 }
1642 }
1643
1644 case _degenerated_updaterefs:
1645 if (has_forwarded_objects()) {
1646 op_final_updaterefs();
1647 if (cancelled_gc()) {
1648 op_degenerated_fail();
1649 return;
1650 }
1651 }
1652
1653 op_cleanup();
1654 break;
1655
1656 default:
1657 ShouldNotReachHere();
1658 }
1659
1660 if (ShenandoahVerify) {
1661 verifier()->verify_after_degenerated();
1662 }
1663
1664 if (VerifyAfterGC) {
1665 Universe::verify();
1666 }
1667
1668 metrics.snap_after();
1669 metrics.print();
1670
1671 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1672 // because that probably means the heap is overloaded and/or fragmented.
1673 if (!metrics.is_good_progress("Degenerated GC")) {
1674 _progress_last_gc.unset();
1675 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1676 op_degenerated_futile();
1677 } else {
1678 _progress_last_gc.set();
1679 }
1680 }
1681
1682 void ShenandoahHeap::op_degenerated_fail() {
1683 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1684 shenandoah_policy()->record_degenerated_upgrade_to_full();
1685 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1686 }
1687
1688 void ShenandoahHeap::op_degenerated_futile() {
1689 shenandoah_policy()->record_degenerated_upgrade_to_full();
1690 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1691 }
1692
1693 void ShenandoahHeap::stop_concurrent_marking() {
1694 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1695 if (!cancelled_gc()) {
1696 // If we needed to update refs, and concurrent marking has been cancelled,
1697 // we need to finish updating references.
1698 set_has_forwarded_objects(false);
1699 mark_complete_marking_context();
1700 }
1701 set_concurrent_mark_in_progress(false);
1702 }
1703
1704 void ShenandoahHeap::force_satb_flush_all_threads() {
1705 if (!is_concurrent_mark_in_progress()) {
1706 // No need to flush SATBs
1707 return;
1708 }
1709
1710 // Do not block if Threads lock is busy. This avoids the potential deadlock
1711 // when this code is called from the periodic task, and something else is
1712 // expecting the periodic task to complete without blocking. On the off-chance
1713 // Threads lock is busy momentarily, try to acquire several times.
1714 for (int t = 0; t < 10; t++) {
1715 if (Threads_lock->try_lock()) {
1716 JavaThread::set_force_satb_flush_all_threads(true);
1717 Threads_lock->unlock();
1718
1719 // The threads are not "acquiring" their thread-local data, but it does not
1720 // hurt to "release" the updates here anyway.
1721 OrderAccess::fence();
1722 break;
1723 }
1724 os::naked_short_sleep(1);
1725 }
1726 }
1727
1728 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1729 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1730 _gc_state.set_cond(mask, value);
1731 JavaThread::set_gc_state_all_threads(_gc_state.raw_value());
1732 }
1733
1734 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1735 set_gc_state_mask(MARKING, in_progress);
1736 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1737 }
1738
1739 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1740 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1741 set_gc_state_mask(EVACUATION, in_progress);
1742 }
1743
1744 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1745 // Initialize Brooks pointer for the next object
1746 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1747 ShenandoahBrooksPointer::initialize(oop(result));
1748 return result;
1749 }
1750
1751 uint ShenandoahHeap::oop_extra_words() {
1752 return ShenandoahBrooksPointer::word_size();
1753 }
1754
1755 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1756 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1757 }
1758
1759 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1760 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1761 }
1762
1763 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1764 if (oopDesc::is_null(obj)) {
1765 return false;
1766 }
1767 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1768 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
1769 return _mark_context->is_marked(obj);
1770 }
1771
1772 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1773 if (oopDesc::is_null(obj)) {
1774 return false;
1775 }
1776 shenandoah_assert_not_forwarded(NULL, obj);
1777 return _mark_context->is_marked(obj);
1778 }
1779
1780 void ShenandoahHeap::ref_processing_init() {
1781 MemRegion mr = reserved_region();
1782
1783 assert(_max_workers > 0, "Sanity");
1784
1785 _ref_processor =
1786 new ReferenceProcessor(mr, // span
1787 ParallelRefProcEnabled, // MT processing
1788 _max_workers, // Degree of MT processing
1789 true, // MT discovery
1790 _max_workers, // Degree of MT discovery
1791 false, // Reference discovery is not atomic
1792 NULL); // No closure, should be installed before use
1793
1794 shenandoah_assert_rp_isalive_not_installed();
1795 }
1796
1797 void ShenandoahHeap::acquire_pending_refs_lock() {
1798 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::acquirePLL);
1799 }
1800
1801 void ShenandoahHeap::release_pending_refs_lock() {
1802 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
1803 }
1804
1805 GCTracer* ShenandoahHeap::tracer() {
1806 return shenandoah_policy()->tracer();
1807 }
1808
1809 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1810 return _free_set->used();
1811 }
1812
1813 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1814 if (try_cancel_gc()) {
1815 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1816 log_info(gc)("%s", msg.buffer());
1817 Events::log(Thread::current(), "%s", msg.buffer());
1818 }
1819 }
1820
1821 uint ShenandoahHeap::max_workers() {
1822 return _max_workers;
1823 }
1824
1825 void ShenandoahHeap::stop() {
1826 // The shutdown sequence should be able to terminate when GC is running.
1827
1828 // Step 0. Notify policy to disable event recording.
1829 _shenandoah_policy->record_shutdown();
1830
1831 // Step 1. Notify control thread that we are in shutdown.
1832 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1833 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1834 _control_thread->prepare_for_graceful_shutdown();
1835
1836 // Step 2. Notify GC workers that we are cancelling GC.
1837 cancel_gc(GCCause::_shenandoah_stop_vm);
1838
1839 // Step 3. Wait until GC worker exits normally.
1840 _control_thread->stop();
1841
1842 // Step 4. Stop String Dedup thread if it is active
1843 if (ShenandoahStringDedup::is_enabled()) {
1844 ShenandoahStringDedup::stop();
1845 }
1846 }
1847
1848 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1849 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1850
1851 ShenandoahGCPhase root_phase(full_gc ?
1852 ShenandoahPhaseTimings::full_gc_purge :
1853 ShenandoahPhaseTimings::purge);
1854
1855 ShenandoahIsAliveSelector alive;
1856 BoolObjectClosure* is_alive = alive.is_alive_closure();
1857
1858 bool purged_class;
1859
1860 // Unload classes and purge SystemDictionary.
1861 {
1862 ShenandoahGCPhase phase(full_gc ?
1863 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1864 ShenandoahPhaseTimings::purge_class_unload);
1865 purged_class = SystemDictionary::do_unloading(is_alive,
1866 full_gc /* do_cleaning*/ );
1867 }
1868
1869 {
1870 ShenandoahGCPhase phase(full_gc ?
1871 ShenandoahPhaseTimings::full_gc_purge_par :
1872 ShenandoahPhaseTimings::purge_par);
1873 uint active = _workers->active_workers();
1874 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
1875 _workers->run_task(&unlink_task);
1876 }
1877
1878 if (ShenandoahStringDedup::is_enabled()) {
1879 ShenandoahGCPhase phase(full_gc ?
1880 ShenandoahPhaseTimings::full_gc_purge_string_dedup :
1881 ShenandoahPhaseTimings::purge_string_dedup);
1882 ShenandoahStringDedup::parallel_cleanup();
1883 }
1884
1885 {
1886 ShenandoahGCPhase phase(full_gc ?
1887 ShenandoahPhaseTimings::full_gc_purge_cldg :
1888 ShenandoahPhaseTimings::purge_cldg);
1889 ClassLoaderDataGraph::purge();
1890 }
1891 }
1892
1893 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1894 set_gc_state_mask(HAS_FORWARDED, cond);
1895 }
1896
1897 void ShenandoahHeap::set_process_references(bool pr) {
1898 _process_references.set_cond(pr);
1899 }
1900
1901 void ShenandoahHeap::set_unload_classes(bool uc) {
1902 _unload_classes.set_cond(uc);
1903 }
1904
1905 bool ShenandoahHeap::process_references() const {
1906 return _process_references.is_set();
1907 }
1908
1909 bool ShenandoahHeap::unload_classes() const {
1910 return _unload_classes.is_set();
1911 }
1912
1913 address ShenandoahHeap::in_cset_fast_test_addr() {
1914 ShenandoahHeap* heap = ShenandoahHeap::heap();
1915 assert(heap->collection_set() != NULL, "Sanity");
1916 return (address) heap->collection_set()->biased_map_address();
1917 }
1918
1919 address ShenandoahHeap::cancelled_gc_addr() {
1920 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
1921 }
1922
1923 address ShenandoahHeap::gc_state_addr() {
1924 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
1925 }
1926
1927 size_t ShenandoahHeap::conservative_max_heap_alignment() {
1928 size_t align = ShenandoahMaxRegionSize;
1929 if (UseLargePages) {
1930 align = MAX2(align, os::large_page_size());
1931 }
1932 return align;
1933 }
1934
1935 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
1936 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
1937 }
1938
1939 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
1940 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
1941 }
1942
1943 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
1944 _degenerated_gc_in_progress.set_cond(in_progress);
1945 }
1946
1947 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1948 _full_gc_in_progress.set_cond(in_progress);
1949 }
1950
1951 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
1952 assert (is_full_gc_in_progress(), "should be");
1953 _full_gc_move_in_progress.set_cond(in_progress);
1954 }
1955
1956 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1957 set_gc_state_mask(UPDATEREFS, in_progress);
1958 }
1959
1960 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1961 ShenandoahCodeRoots::add_nmethod(nm);
1962 }
1963
1964 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
1965 ShenandoahCodeRoots::remove_nmethod(nm);
1966 }
1967
1968 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
1969 o = barrier_set()->write_barrier(o);
1970 ShenandoahHeapLocker locker(lock());
1971 heap_region_containing(o)->make_pinned();
1972 return o;
1973 }
1974
1975 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
1976 o = barrier_set()->read_barrier(o);
1977 ShenandoahHeapLocker locker(lock());
1978 heap_region_containing(o)->make_unpinned();
1979 }
1980
1981 GCTimer* ShenandoahHeap::gc_timer() const {
1982 return _gc_timer;
1983 }
1984
1985 #ifdef ASSERT
1986 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
1987 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
1988
1989 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1990 if (UseDynamicNumberOfGCThreads ||
1991 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
1992 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
1993 } else {
1994 // Use ParallelGCThreads inside safepoints
1995 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
1996 }
1997 } else {
1998 if (UseDynamicNumberOfGCThreads ||
1999 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2000 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2001 } else {
2002 // Use ConcGCThreads outside safepoints
2003 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2004 }
2005 }
2006 }
2007 #endif
2008
2009 ShenandoahVerifier* ShenandoahHeap::verifier() {
2010 guarantee(ShenandoahVerify, "Should be enabled");
2011 assert (_verifier != NULL, "sanity");
2012 return _verifier;
2013 }
2014
2015 ShenandoahUpdateHeapRefsClosure::ShenandoahUpdateHeapRefsClosure() :
2016 _heap(ShenandoahHeap::heap()) {}
2017
2018 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2019 private:
2020 ShenandoahHeap* _heap;
2021 ShenandoahRegionIterator* _regions;
2022 bool _concurrent;
2023
2024 public:
2025 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2026 AbstractGangTask("Concurrent Update References Task"),
2027 _heap(ShenandoahHeap::heap()),
2028 _regions(regions),
2029 _concurrent(concurrent) {
2030 }
2031
2032 void work(uint worker_id) {
2033 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2034 ShenandoahUpdateHeapRefsClosure cl;
2035 ShenandoahHeapRegion* r = _regions->next();
2036 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2037 while (r != NULL) {
2038 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2039 assert (top_at_start_ur >= r->bottom(), "sanity");
2040 if (r->is_active() && !r->is_cset()) {
2041 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2042 }
2043 if (ShenandoahPacing) {
2044 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2045 }
2046 if (_heap->cancelled_gc()) {
2047 return;
2048 }
2049 r = _regions->next();
2050 }
2051 }
2052 };
2053
2054 void ShenandoahHeap::update_heap_references(bool concurrent) {
2055 ShenandoahUpdateHeapRefsTask task(&_update_refs_iterator, concurrent);
2056 workers()->run_task(&task);
2057 }
2058
2059 void ShenandoahHeap::op_init_updaterefs() {
2060 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2061
2062 set_evacuation_in_progress(false);
2063
2064 if (ShenandoahVerify) {
2065 verifier()->verify_before_updaterefs();
2066 }
2067
2068 set_update_refs_in_progress(true);
2069 make_parsable(true);
2070 for (uint i = 0; i < num_regions(); i++) {
2071 ShenandoahHeapRegion* r = get_region(i);
2072 r->set_concurrent_iteration_safe_limit(r->top());
2073 }
2074
2075 // Reset iterator.
2076 _update_refs_iterator.reset();
2077
2078 if (ShenandoahPacing) {
2079 pacer()->setup_for_updaterefs();
2080 }
2081 }
2082
2083 void ShenandoahHeap::op_final_updaterefs() {
2084 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2085
2086 // Check if there is left-over work, and finish it
2087 if (_update_refs_iterator.has_next()) {
2088 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2089
2090 // Finish updating references where we left off.
2091 clear_cancelled_gc();
2092 update_heap_references(false);
2093 }
2094
2095 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2096 // everything. On degenerated paths, cancelled gc would not be set anyway.
2097 if (cancelled_gc()) {
2098 clear_cancelled_gc();
2099 }
2100 assert(!cancelled_gc(), "Should have been done right before");
2101
2102 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2103 ShenandoahPhaseTimings::degen_gc_update_roots:
2104 ShenandoahPhaseTimings::final_update_refs_roots);
2105
2106 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2107
2108 trash_cset_regions();
2109 set_has_forwarded_objects(false);
2110 set_update_refs_in_progress(false);
2111
2112 if (ShenandoahVerify) {
2113 verifier()->verify_after_updaterefs();
2114 }
2115
2116 if (VerifyAfterGC) {
2117 Universe::verify();
2118 }
2119
2120 {
2121 ShenandoahHeapLocker locker(lock());
2122 _free_set->rebuild();
2123 }
2124 }
2125
2126 #ifdef ASSERT
2127 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2128 _lock.assert_not_owned_by_current_thread();
2129 }
2130
2131 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2132 _lock.assert_owned_by_current_thread();
2133 }
2134
2135 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2136 _lock.assert_owned_by_current_thread_or_safepoint();
2137 }
2138 #endif
2139
2140 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2141 print_on(st);
2142 print_heap_regions_on(st);
2143 }
2144
2145 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2146 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2147
2148 size_t regions_from = _bitmap_regions_per_slice * slice;
2149 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2150 for (size_t g = regions_from; g < regions_to; g++) {
2151 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2152 if (skip_self && g == r->region_number()) continue;
2153 if (get_region(g)->is_committed()) {
2154 return true;
2155 }
2156 }
2157 return false;
2158 }
2159
2160 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2161 assert_heaplock_owned_by_current_thread();
2162
2163 // Bitmaps in special regions do not need commits
2164 if (_bitmap_region_special) {
2165 return true;
2166 }
2167
2168 if (is_bitmap_slice_committed(r, true)) {
2169 // Some other region from the group is already committed, meaning the bitmap
2170 // slice is already committed, we exit right away.
2171 return true;
2172 }
2173
2174 // Commit the bitmap slice:
2175 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2176 size_t off = _bitmap_bytes_per_slice * slice;
2177 size_t len = _bitmap_bytes_per_slice;
2178 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2179 return false;
2180 }
2181 return true;
2182 }
2183
2184 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2185 assert_heaplock_owned_by_current_thread();
2186
2187 // Bitmaps in special regions do not need uncommits
2188 if (_bitmap_region_special) {
2189 return true;
2190 }
2191
2192 if (is_bitmap_slice_committed(r, true)) {
2193 // Some other region from the group is still committed, meaning the bitmap
2194 // slice is should stay committed, exit right away.
2195 return true;
2196 }
2197
2198 // Uncommit the bitmap slice:
2199 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2200 size_t off = _bitmap_bytes_per_slice * slice;
2201 size_t len = _bitmap_bytes_per_slice;
2202 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2203 return false;
2204 }
2205 return true;
2206 }
2207
2208 void ShenandoahHeap::vmop_entry_init_mark() {
2209 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2210 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2211 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2212
2213 try_inject_alloc_failure();
2214 VM_ShenandoahInitMark op;
2215 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2216 }
2217
2218 void ShenandoahHeap::vmop_entry_final_mark() {
2219 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2220 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2221 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2222
2223 try_inject_alloc_failure();
2224 VM_ShenandoahFinalMarkStartEvac op;
2225 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2226 }
2227
2228 void ShenandoahHeap::vmop_entry_final_evac() {
2229 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2230 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2231 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2232
2233 VM_ShenandoahFinalEvac op;
2234 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2235 }
2236
2237 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2238 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2239 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2240 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2241
2242 try_inject_alloc_failure();
2243 VM_ShenandoahInitUpdateRefs op;
2244 VMThread::execute(&op);
2245 }
2246
2247 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2248 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2249 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2250 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2251
2252 try_inject_alloc_failure();
2253 VM_ShenandoahFinalUpdateRefs op;
2254 VMThread::execute(&op);
2255 }
2256
2257 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2258 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2259 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2260 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2261
2262 try_inject_alloc_failure();
2263 VM_ShenandoahFullGC op(cause);
2264 VMThread::execute(&op);
2265 }
2266
2267 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2268 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2269 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2270 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2271
2272 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2273 VMThread::execute(°enerated_gc);
2274 }
2275
2276 void ShenandoahHeap::entry_init_mark() {
2277 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2278 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2279
2280 const char* msg = init_mark_event_message();
2281 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2282 EventMark em("%s", msg);
2283
2284 ShenandoahWorkerScope scope(workers(),
2285 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2286 "init marking");
2287
2288 op_init_mark();
2289 }
2290
2291 void ShenandoahHeap::entry_final_mark() {
2292 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2293 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2294
2295 const char* msg = final_mark_event_message();
2296 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2297 EventMark em("%s", msg);
2298
2299 ShenandoahWorkerScope scope(workers(),
2300 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2301 "final marking");
2302
2303 op_final_mark();
2304 }
2305
2306 void ShenandoahHeap::entry_final_evac() {
2307 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2308 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2309
2310 const char* msg = "Pause Final Evac";
2311 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2312 EventMark em("%s", msg);
2313
2314 op_final_evac();
2315 }
2316
2317 void ShenandoahHeap::entry_init_updaterefs() {
2318 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2319 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2320
2321 static const char* msg = "Pause Init Update Refs";
2322 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2323 EventMark em("%s", msg);
2324
2325 // No workers used in this phase, no setup required
2326
2327 op_init_updaterefs();
2328 }
2329
2330 void ShenandoahHeap::entry_final_updaterefs() {
2331 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2332 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2333
2334 static const char* msg = "Pause Final Update Refs";
2335 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id());
2336 EventMark em("%s", msg);
2337
2338 ShenandoahWorkerScope scope(workers(),
2339 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2340 "final reference update");
2341
2342 op_final_updaterefs();
2343 }
2344
2345 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2346 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2347 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2348
2349 static const char* msg = "Pause Full";
2350 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true);
2351 EventMark em("%s", msg);
2352
2353 ShenandoahWorkerScope scope(workers(),
2354 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2355 "full gc");
2356
2357 op_full(cause);
2358 }
2359
2360 void ShenandoahHeap::entry_degenerated(int point) {
2361 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2362 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2363
2364 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2365 const char* msg = degen_event_message(dpoint);
2366 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true);
2367 EventMark em("%s", msg);
2368
2369 ShenandoahWorkerScope scope(workers(),
2370 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2371 "stw degenerated gc");
2372
2373 set_degenerated_gc_in_progress(true);
2374 op_degenerated(dpoint);
2375 set_degenerated_gc_in_progress(false);
2376 }
2377
2378 void ShenandoahHeap::entry_mark() {
2379 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2380
2381 const char* msg = conc_mark_event_message();
2382 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2383 EventMark em("%s", msg);
2384
2385 ShenandoahWorkerScope scope(workers(),
2386 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2387 "concurrent marking");
2388
2389 try_inject_alloc_failure();
2390 op_mark();
2391 }
2392
2393 void ShenandoahHeap::entry_evac() {
2394 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2395 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2396
2397 static const char *msg = "Concurrent evacuation";
2398 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2399 EventMark em("%s", msg);
2400
2401 ShenandoahWorkerScope scope(workers(),
2402 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2403 "concurrent evacuation");
2404
2405 try_inject_alloc_failure();
2406 op_conc_evac();
2407 }
2408
2409 void ShenandoahHeap::entry_updaterefs() {
2410 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2411
2412 static const char* msg = "Concurrent update references";
2413 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2414 EventMark em("%s", msg);
2415
2416 ShenandoahWorkerScope scope(workers(),
2417 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2418 "concurrent reference update");
2419
2420 try_inject_alloc_failure();
2421 op_updaterefs();
2422 }
2423
2424 void ShenandoahHeap::entry_cleanup() {
2425 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2426
2427 static const char* msg = "Concurrent cleanup";
2428 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2429 EventMark em("%s", msg);
2430
2431 // This phase does not use workers, no need for setup
2432
2433 try_inject_alloc_failure();
2434 op_cleanup();
2435 }
2436
2437 void ShenandoahHeap::entry_reset() {
2438 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2439
2440 static const char* msg = "Concurrent reset";
2441 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2442 EventMark em("%s", msg);
2443
2444 ShenandoahWorkerScope scope(workers(),
2445 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2446 "concurrent reset");
2447
2448 try_inject_alloc_failure();
2449 op_reset();
2450 }
2451
2452 void ShenandoahHeap::entry_preclean() {
2453 if (ShenandoahPreclean && process_references()) {
2454 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2455
2456 static const char* msg = "Concurrent precleaning";
2457 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2458 EventMark em("%s", msg);
2459
2460 ShenandoahWorkerScope scope(workers(),
2461 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2462 "concurrent preclean",
2463 /* check_workers = */ false);
2464
2465 try_inject_alloc_failure();
2466 op_preclean();
2467 }
2468 }
2469
2470 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2471 static const char *msg = "Concurrent uncommit";
2472 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true);
2473 EventMark em("%s", msg);
2474
2475 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2476
2477 op_uncommit(shrink_before);
2478 }
2479
2480 void ShenandoahHeap::try_inject_alloc_failure() {
2481 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2482 _inject_alloc_failure.set();
2483 os::naked_short_sleep(1);
2484 if (cancelled_gc()) {
2485 log_info(gc)("Allocation failure was successfully injected");
2486 }
2487 }
2488 }
2489
2490 bool ShenandoahHeap::should_inject_alloc_failure() {
2491 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2492 }
2493
2494 void ShenandoahHeap::enter_evacuation() {
2495 _oom_evac_handler.enter_evacuation();
2496 }
2497
2498 void ShenandoahHeap::leave_evacuation() {
2499 _oom_evac_handler.leave_evacuation();
2500 }
2501
2502 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2503 _heap(ShenandoahHeap::heap()),
2504 _index(0) {}
2505
2506 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2507 _heap(heap),
2508 _index(0) {}
2509
2510 void ShenandoahRegionIterator::reset() {
2511 _index = 0;
2512 }
2513
2514 bool ShenandoahRegionIterator::has_next() const {
2515 return _index < (jint)_heap->num_regions();
2516 }
2517
2518 char ShenandoahHeap::gc_state() {
2519 return _gc_state.raw_value();
2520 }
2521
2522 const char* ShenandoahHeap::init_mark_event_message() const {
2523 bool update_refs = has_forwarded_objects();
2524 bool proc_refs = process_references();
2525 bool unload_cls = unload_classes();
2526
2527 if (update_refs && proc_refs && unload_cls) {
2528 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2529 } else if (update_refs && proc_refs) {
2530 return "Pause Init Mark (update refs) (process weakrefs)";
2531 } else if (update_refs && unload_cls) {
2532 return "Pause Init Mark (update refs) (unload classes)";
2533 } else if (proc_refs && unload_cls) {
2534 return "Pause Init Mark (process weakrefs) (unload classes)";
2535 } else if (update_refs) {
2536 return "Pause Init Mark (update refs)";
2537 } else if (proc_refs) {
2538 return "Pause Init Mark (process weakrefs)";
2539 } else if (unload_cls) {
2540 return "Pause Init Mark (unload classes)";
2541 } else {
2542 return "Pause Init Mark";
2543 }
2544 }
2545
2546 const char* ShenandoahHeap::final_mark_event_message() const {
2547 bool update_refs = has_forwarded_objects();
2548 bool proc_refs = process_references();
2549 bool unload_cls = unload_classes();
2550
2551 if (update_refs && proc_refs && unload_cls) {
2552 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2553 } else if (update_refs && proc_refs) {
2554 return "Pause Final Mark (update refs) (process weakrefs)";
2555 } else if (update_refs && unload_cls) {
2556 return "Pause Final Mark (update refs) (unload classes)";
2557 } else if (proc_refs && unload_cls) {
2558 return "Pause Final Mark (process weakrefs) (unload classes)";
2559 } else if (update_refs) {
2560 return "Pause Final Mark (update refs)";
2561 } else if (proc_refs) {
2562 return "Pause Final Mark (process weakrefs)";
2563 } else if (unload_cls) {
2564 return "Pause Final Mark (unload classes)";
2565 } else {
2566 return "Pause Final Mark";
2567 }
2568 }
2569
2570 const char* ShenandoahHeap::conc_mark_event_message() const {
2571 bool update_refs = has_forwarded_objects();
2572 bool proc_refs = process_references();
2573 bool unload_cls = unload_classes();
2574
2575 if (update_refs && proc_refs && unload_cls) {
2576 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2577 } else if (update_refs && proc_refs) {
2578 return "Concurrent marking (update refs) (process weakrefs)";
2579 } else if (update_refs && unload_cls) {
2580 return "Concurrent marking (update refs) (unload classes)";
2581 } else if (proc_refs && unload_cls) {
2582 return "Concurrent marking (process weakrefs) (unload classes)";
2583 } else if (update_refs) {
2584 return "Concurrent marking (update refs)";
2585 } else if (proc_refs) {
2586 return "Concurrent marking (process weakrefs)";
2587 } else if (unload_cls) {
2588 return "Concurrent marking (unload classes)";
2589 } else {
2590 return "Concurrent marking";
2591 }
2592 }
2593
2594 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2595 switch (point) {
2596 case _degenerated_unset:
2597 return "Pause Degenerated GC (<UNSET>)";
2598 case _degenerated_outside_cycle:
2599 return "Pause Degenerated GC (Outside of Cycle)";
2600 case _degenerated_mark:
2601 return "Pause Degenerated GC (Mark)";
2602 case _degenerated_evac:
2603 return "Pause Degenerated GC (Evacuation)";
2604 case _degenerated_updaterefs:
2605 return "Pause Degenerated GC (Update Refs)";
2606 default:
2607 ShouldNotReachHere();
2608 return "ERROR";
2609 }
2610 }
2611
2612 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2613 #ifdef ASSERT
2614 assert(_liveness_cache != NULL, "sanity");
2615 assert(worker_id < _max_workers, "sanity");
2616 for (uint i = 0; i < num_regions(); i++) {
2617 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2618 }
2619 #endif
2620 return _liveness_cache[worker_id];
2621 }
2622
2623 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2624 assert(worker_id < _max_workers, "sanity");
2625 assert(_liveness_cache != NULL, "sanity");
2626 jushort* ld = _liveness_cache[worker_id];
2627 for (uint i = 0; i < num_regions(); i++) {
2628 ShenandoahHeapRegion* r = get_region(i);
2629 jushort live = ld[i];
2630 if (live > 0) {
2631 r->increase_live_data_gc_words(live);
2632 ld[i] = 0;
2633 }
2634 }
2635 }
2636
2637 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2638 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2639 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2640 }