1 /*
2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/memAllocator.hpp"
30 #include "gc/shared/parallelCleaning.hpp"
31 #include "gc/shared/plab.hpp"
32
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahBrooksPointer.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
37 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
47 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
48 #include "gc/shenandoah/shenandoahMetrics.hpp"
49 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
50 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
51 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
52 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
53 #include "gc/shenandoah/shenandoahStringDedup.hpp"
54 #include "gc/shenandoah/shenandoahUtils.hpp"
55 #include "gc/shenandoah/shenandoahVerifier.hpp"
56 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
57 #include "gc/shenandoah/shenandoahVMOperations.hpp"
58 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
59 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
66
67 #include "memory/metaspace.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/safepointMechanism.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/mallocTracker.hpp"
72
73 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
74
75 #ifdef ASSERT
76 template <class T>
77 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
78 T o = RawAccess<>::oop_load(p);
79 if (! CompressedOops::is_null(o)) {
80 oop obj = CompressedOops::decode_not_null(o);
81 shenandoah_assert_not_forwarded(p, obj);
82 }
83 }
84
85 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
86 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
87 #endif
88
89 class ShenandoahPretouchHeapTask : public AbstractGangTask {
90 private:
91 ShenandoahRegionIterator _regions;
92 const size_t _page_size;
93 public:
94 ShenandoahPretouchHeapTask(size_t page_size) :
95 AbstractGangTask("Shenandoah Pretouch Heap"),
96 _page_size(page_size) {}
97
98 virtual void work(uint worker_id) {
99 ShenandoahHeapRegion* r = _regions.next();
100 while (r != NULL) {
101 os::pretouch_memory(r->bottom(), r->end(), _page_size);
102 r = _regions.next();
103 }
104 }
105 };
106
107 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
108 private:
109 ShenandoahRegionIterator _regions;
110 char* _bitmap_base;
111 const size_t _bitmap_size;
112 const size_t _page_size;
113 public:
114 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
115 AbstractGangTask("Shenandoah Pretouch Bitmap"),
116 _bitmap_base(bitmap_base),
117 _bitmap_size(bitmap_size),
118 _page_size(page_size) {}
119
120 virtual void work(uint worker_id) {
121 ShenandoahHeapRegion* r = _regions.next();
122 while (r != NULL) {
123 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
124 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
125 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
126
127 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
128
129 r = _regions.next();
130 }
131 }
132 };
133
134 jint ShenandoahHeap::initialize() {
135 ShenandoahBrooksPointer::initial_checks();
136
137 initialize_heuristics();
138
139 //
140 // Figure out heap sizing
141 //
142
143 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
144 size_t max_byte_size = collector_policy()->max_heap_byte_size();
145 size_t heap_alignment = collector_policy()->heap_alignment();
146
147 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
148
149 if (ShenandoahAlwaysPreTouch) {
150 // Enabled pre-touch means the entire heap is committed right away.
151 init_byte_size = max_byte_size;
152 }
153
154 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
155 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
156
157 _num_regions = ShenandoahHeapRegion::region_count();
158
159 size_t num_committed_regions = init_byte_size / reg_size_bytes;
160 num_committed_regions = MIN2(num_committed_regions, _num_regions);
161 assert(num_committed_regions <= _num_regions, "sanity");
162
163 _initial_size = num_committed_regions * reg_size_bytes;
164 _committed = _initial_size;
165
166 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
167 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
168
169 //
170 // Reserve and commit memory for heap
171 //
172
173 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
174 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
175 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
176 _heap_region_special = heap_rs.special();
177
178 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
179 "Misaligned heap: " PTR_FORMAT, p2i(base()));
180
181 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
182 if (!_heap_region_special) {
183 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
184 "Cannot commit heap memory");
185 }
186
187 //
188 // Reserve and commit memory for bitmap(s)
189 //
190
191 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
192 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
193
194 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
195
196 guarantee(bitmap_bytes_per_region != 0,
197 "Bitmap bytes per region should not be zero");
198 guarantee(is_power_of_2(bitmap_bytes_per_region),
199 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
200
201 if (bitmap_page_size > bitmap_bytes_per_region) {
202 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
203 _bitmap_bytes_per_slice = bitmap_page_size;
204 } else {
205 _bitmap_regions_per_slice = 1;
206 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
207 }
208
209 guarantee(_bitmap_regions_per_slice >= 1,
210 "Should have at least one region per slice: " SIZE_FORMAT,
211 _bitmap_regions_per_slice);
212
213 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
214 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
215 _bitmap_bytes_per_slice, bitmap_page_size);
216
217 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
218 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
219 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
220 _bitmap_region_special = bitmap.special();
221
222 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
223 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
224 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
225 if (!_bitmap_region_special) {
226 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
227 "Cannot commit bitmap memory");
228 }
229
230 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
231
232 if (ShenandoahVerify) {
233 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
234 if (!verify_bitmap.special()) {
235 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
236 "Cannot commit verification bitmap memory");
237 }
238 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
239 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
240 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
241 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
242 }
243
244 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
245 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
246 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
247 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
248 _aux_bitmap_region_special = aux_bitmap.special();
249 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
250
251 //
252 // Create regions and region sets
253 //
254
255 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
256 _free_set = new ShenandoahFreeSet(this, _num_regions);
257 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)sh_rs.base());
258
259 {
260 ShenandoahHeapLocker locker(lock());
261
262 size_t size_words = ShenandoahHeapRegion::region_size_words();
263
264 for (size_t i = 0; i < _num_regions; i++) {
265 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
266 bool is_committed = i < num_committed_regions;
267 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
268
269 _marking_context->initialize_top_at_mark_start(r);
270 _regions[i] = r;
271 assert(!collection_set()->is_in(i), "New region should not be in collection set");
272 }
273
274 // Initialize to complete
275 _marking_context->mark_complete();
276
277 _free_set->rebuild();
278 }
279
280 if (ShenandoahAlwaysPreTouch) {
281 assert(!AlwaysPreTouch, "Should have been overridden");
282
283 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
284 // before initialize() below zeroes it with initializing thread. For any given region,
285 // we touch the region and the corresponding bitmaps from the same thread.
286 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
287
288 size_t pretouch_heap_page_size = heap_page_size;
289 size_t pretouch_bitmap_page_size = bitmap_page_size;
290
291 #ifdef LINUX
292 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
293 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
294 // them into huge one. Therefore, we need to pretouch with smaller pages.
295 if (UseTransparentHugePages) {
296 pretouch_heap_page_size = (size_t)os::vm_page_size();
297 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
298 }
299 #endif
300
301 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
302 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
303
304 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
305 _num_regions, pretouch_bitmap_page_size);
306 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
307 _workers->run_task(&bcl);
308
309 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
310 _num_regions, pretouch_heap_page_size);
311 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
312 _workers->run_task(&hcl);
313 }
314
315 //
316 // Initialize the rest of GC subsystems
317 //
318
319 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
320 for (uint worker = 0; worker < _max_workers; worker++) {
321 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
322 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
323 }
324
325 // The call below uses stuff (the SATB* things) that are in G1, but probably
326 // belong into a shared location.
327 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
328 SATB_Q_CBL_mon,
329 20 /* G1SATBProcessCompletedThreshold */,
330 60 /* G1SATBBufferEnqueueingThresholdPercent */);
331
332 _monitoring_support = new ShenandoahMonitoringSupport(this);
333 _phase_timings = new ShenandoahPhaseTimings();
334 ShenandoahStringDedup::initialize();
335 ShenandoahCodeRoots::initialize();
336
337 if (ShenandoahAllocationTrace) {
338 _alloc_tracker = new ShenandoahAllocTracker();
339 }
340
341 if (ShenandoahPacing) {
342 _pacer = new ShenandoahPacer(this);
343 _pacer->setup_for_idle();
344 } else {
345 _pacer = NULL;
346 }
347
348 _traversal_gc = heuristics()->can_do_traversal_gc() ?
349 new ShenandoahTraversalGC(this, _num_regions) :
350 NULL;
351
352 _control_thread = new ShenandoahControlThread();
353
354 log_info(gc, init)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
355 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
356
357 log_info(gc, init)("Safepointing mechanism: %s",
358 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
359 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
360
361 return JNI_OK;
362 }
363
364 void ShenandoahHeap::initialize_heuristics() {
365 if (ShenandoahGCHeuristics != NULL) {
366 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
367 _heuristics = new ShenandoahAggressiveHeuristics();
368 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
369 _heuristics = new ShenandoahStaticHeuristics();
370 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
371 _heuristics = new ShenandoahAdaptiveHeuristics();
372 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
373 _heuristics = new ShenandoahPassiveHeuristics();
374 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
375 _heuristics = new ShenandoahCompactHeuristics();
376 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
377 _heuristics = new ShenandoahTraversalHeuristics();
378 } else {
379 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
380 }
381
382 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
383 vm_exit_during_initialization(
384 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
385 _heuristics->name()));
386 }
387 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
388 vm_exit_during_initialization(
389 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
390 _heuristics->name()));
391 }
392 log_info(gc, init)("Shenandoah heuristics: %s",
393 _heuristics->name());
394 } else {
395 ShouldNotReachHere();
396 }
397
398 }
399
400 #ifdef _MSC_VER
401 #pragma warning( push )
402 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
403 #endif
404
405 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
406 CollectedHeap(),
407 _initial_size(0),
408 _used(0),
409 _committed(0),
410 _bytes_allocated_since_gc_start(0),
411 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
412 _workers(NULL),
413 _safepoint_workers(NULL),
414 _heap_region_special(false),
415 _num_regions(0),
416 _regions(NULL),
417 _update_refs_iterator(this),
418 _control_thread(NULL),
419 _shenandoah_policy(policy),
420 _heuristics(NULL),
421 _free_set(NULL),
422 _scm(new ShenandoahConcurrentMark()),
423 _traversal_gc(NULL),
424 _full_gc(new ShenandoahMarkCompact()),
425 _pacer(NULL),
426 _verifier(NULL),
427 _alloc_tracker(NULL),
428 _phase_timings(NULL),
429 _monitoring_support(NULL),
430 _memory_pool(NULL),
431 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
432 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
433 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
434 _soft_ref_policy(),
435 _ref_processor(NULL),
436 _marking_context(NULL),
437 _bitmap_size(0),
438 _bitmap_regions_per_slice(0),
439 _bitmap_bytes_per_slice(0),
440 _bitmap_region_special(false),
441 _aux_bitmap_region_special(false),
442 _liveness_cache(NULL),
443 _collection_set(NULL)
444 {
445 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
446 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
447
448 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
449
450 _max_workers = MAX2(_max_workers, 1U);
451 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
452 /* are_GC_task_threads */true,
453 /* are_ConcurrentGC_threads */false);
454 if (_workers == NULL) {
455 vm_exit_during_initialization("Failed necessary allocation.");
456 } else {
457 _workers->initialize_workers();
458 }
459
460 if (ShenandoahParallelSafepointThreads > 1) {
461 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
462 ShenandoahParallelSafepointThreads,
463 false, false);
464 _safepoint_workers->initialize_workers();
465 }
466 }
467
468 #ifdef _MSC_VER
469 #pragma warning( pop )
470 #endif
471
472 class ShenandoahResetBitmapTask : public AbstractGangTask {
473 private:
474 ShenandoahRegionIterator _regions;
475
476 public:
477 ShenandoahResetBitmapTask() :
478 AbstractGangTask("Parallel Reset Bitmap Task") {}
479
480 void work(uint worker_id) {
481 ShenandoahHeapRegion* region = _regions.next();
482 ShenandoahHeap* heap = ShenandoahHeap::heap();
483 ShenandoahMarkingContext* const ctx = heap->marking_context();
484 while (region != NULL) {
485 if (heap->is_bitmap_slice_committed(region)) {
486 ctx->clear_bitmap(region);
487 }
488 region = _regions.next();
489 }
490 }
491 };
492
493 void ShenandoahHeap::reset_mark_bitmap() {
494 assert_gc_workers(_workers->active_workers());
495 mark_incomplete_marking_context();
496
497 ShenandoahResetBitmapTask task;
498 _workers->run_task(&task);
499 }
500
501 void ShenandoahHeap::print_on(outputStream* st) const {
502 st->print_cr("Shenandoah Heap");
503 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
504 capacity() / K, committed() / K, used() / K);
505 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
506 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
507
508 st->print("Status: ");
509 if (has_forwarded_objects()) st->print("has forwarded objects, ");
510 if (is_concurrent_mark_in_progress()) st->print("marking, ");
511 if (is_evacuation_in_progress()) st->print("evacuating, ");
512 if (is_update_refs_in_progress()) st->print("updating refs, ");
513 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
514 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
515 if (is_full_gc_in_progress()) st->print("full gc, ");
516 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
517
518 if (cancelled_gc()) {
519 st->print("cancelled");
520 } else {
521 st->print("not cancelled");
522 }
523 st->cr();
524
525 st->print_cr("Reserved region:");
526 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
527 p2i(reserved_region().start()),
528 p2i(reserved_region().end()));
529
530 st->cr();
531 MetaspaceUtils::print_on(st);
532
533 if (Verbose) {
534 print_heap_regions_on(st);
535 }
536 }
537
538 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
539 public:
540 void do_thread(Thread* thread) {
541 assert(thread != NULL, "Sanity");
542 assert(thread->is_Worker_thread(), "Only worker thread expected");
543 ShenandoahThreadLocalData::initialize_gclab(thread);
544 }
545 };
546
547 void ShenandoahHeap::post_initialize() {
548 CollectedHeap::post_initialize();
549 MutexLocker ml(Threads_lock);
550
551 ShenandoahInitWorkerGCLABClosure init_gclabs;
552 _workers->threads_do(&init_gclabs);
553
554 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
555 // Now, we will let WorkGang to initialize gclab when new worker is created.
556 _workers->set_initialize_gclab();
557
558 _scm->initialize(_max_workers);
559 _full_gc->initialize(_gc_timer);
560
561 ref_processing_init();
562
563 _heuristics->initialize();
564 }
565
566 size_t ShenandoahHeap::used() const {
567 return OrderAccess::load_acquire(&_used);
568 }
569
570 size_t ShenandoahHeap::committed() const {
571 OrderAccess::acquire();
572 return _committed;
573 }
574
575 void ShenandoahHeap::increase_committed(size_t bytes) {
576 assert_heaplock_or_safepoint();
577 _committed += bytes;
578 }
579
580 void ShenandoahHeap::decrease_committed(size_t bytes) {
581 assert_heaplock_or_safepoint();
582 _committed -= bytes;
583 }
584
585 void ShenandoahHeap::increase_used(size_t bytes) {
586 Atomic::add(bytes, &_used);
587 }
588
589 void ShenandoahHeap::set_used(size_t bytes) {
590 OrderAccess::release_store_fence(&_used, bytes);
591 }
592
593 void ShenandoahHeap::decrease_used(size_t bytes) {
594 assert(used() >= bytes, "never decrease heap size by more than we've left");
595 Atomic::sub(bytes, &_used);
596 }
597
598 void ShenandoahHeap::increase_allocated(size_t bytes) {
599 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
600 }
601
602 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
603 size_t bytes = words * HeapWordSize;
604 if (!waste) {
605 increase_used(bytes);
606 }
607 increase_allocated(bytes);
608 if (ShenandoahPacing) {
609 control_thread()->pacing_notify_alloc(words);
610 if (waste) {
611 pacer()->claim_for_alloc(words, true);
612 }
613 }
614 }
615
616 size_t ShenandoahHeap::capacity() const {
617 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
618 }
619
620 size_t ShenandoahHeap::max_capacity() const {
621 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
622 }
623
624 size_t ShenandoahHeap::initial_capacity() const {
625 return _initial_size;
626 }
627
628 bool ShenandoahHeap::is_in(const void* p) const {
629 HeapWord* heap_base = (HeapWord*) base();
630 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
631 return p >= heap_base && p < last_region_end;
632 }
633
634 void ShenandoahHeap::op_uncommit(double shrink_before) {
635 assert (ShenandoahUncommit, "should be enabled");
636
637 size_t count = 0;
638 for (size_t i = 0; i < num_regions(); i++) {
639 ShenandoahHeapRegion* r = get_region(i);
640 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
641 ShenandoahHeapLocker locker(lock());
642 if (r->is_empty_committed()) {
643 r->make_uncommitted();
644 count++;
645 }
646 }
647 SpinPause(); // allow allocators to take the lock
648 }
649
650 if (count > 0) {
651 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
652 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
653 control_thread()->notify_heap_changed();
654 }
655 }
656
657 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
658 // New object should fit the GCLAB size
659 size_t min_size = MAX2(size, PLAB::min_size());
660
661 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
662 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
663 new_size = MIN2(new_size, PLAB::max_size());
664 new_size = MAX2(new_size, PLAB::min_size());
665
666 // Record new heuristic value even if we take any shortcut. This captures
667 // the case when moderately-sized objects always take a shortcut. At some point,
668 // heuristics should catch up with them.
669 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
670
671 if (new_size < size) {
672 // New size still does not fit the object. Fall back to shared allocation.
673 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
674 return NULL;
675 }
676
677 // Retire current GCLAB, and allocate a new one.
678 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
679 gclab->retire();
680
681 size_t actual_size = 0;
682 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
683 if (gclab_buf == NULL) {
684 return NULL;
685 }
686
687 assert (size <= actual_size, "allocation should fit");
688
689 if (ZeroTLAB) {
690 // ..and clear it.
691 Copy::zero_to_words(gclab_buf, actual_size);
692 } else {
693 // ...and zap just allocated object.
694 #ifdef ASSERT
695 // Skip mangling the space corresponding to the object header to
696 // ensure that the returned space is not considered parsable by
697 // any concurrent GC thread.
698 size_t hdr_size = oopDesc::header_size();
699 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
700 #endif // ASSERT
701 }
702 gclab->set_buf(gclab_buf, actual_size);
703 return gclab->allocate(size);
704 }
705
706 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
707 size_t requested_size,
708 size_t* actual_size) {
709 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
710 HeapWord* res = allocate_memory(req);
711 if (res != NULL) {
712 *actual_size = req.actual_size();
713 } else {
714 *actual_size = 0;
715 }
716 return res;
717 }
718
719 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
720 size_t word_size,
721 size_t* actual_size) {
722 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
723 HeapWord* res = allocate_memory(req);
724 if (res != NULL) {
725 *actual_size = req.actual_size();
726 } else {
727 *actual_size = 0;
728 }
729 return res;
730 }
731
732 ShenandoahHeap* ShenandoahHeap::heap() {
733 CollectedHeap* heap = Universe::heap();
734 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
735 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
736 return (ShenandoahHeap*) heap;
737 }
738
739 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
740 CollectedHeap* heap = Universe::heap();
741 return (ShenandoahHeap*) heap;
742 }
743
744 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
745 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
746
747 intptr_t pacer_epoch = 0;
748 bool in_new_region = false;
749 HeapWord* result = NULL;
750
751 if (req.is_mutator_alloc()) {
752 if (ShenandoahPacing) {
753 pacer()->pace_for_alloc(req.size());
754 pacer_epoch = pacer()->epoch();
755 }
756
757 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
758 result = allocate_memory_under_lock(req, in_new_region);
759 }
760
761 // Allocation failed, block until control thread reacted, then retry allocation.
762 //
763 // It might happen that one of the threads requesting allocation would unblock
764 // way later after GC happened, only to fail the second allocation, because
765 // other threads have already depleted the free storage. In this case, a better
766 // strategy is to try again, as long as GC makes progress.
767 //
768 // Then, we need to make sure the allocation was retried after at least one
769 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
770
771 size_t tries = 0;
772
773 while (result == NULL && _progress_last_gc.is_set()) {
774 tries++;
775 control_thread()->handle_alloc_failure(req.size());
776 result = allocate_memory_under_lock(req, in_new_region);
777 }
778
779 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
780 tries++;
781 control_thread()->handle_alloc_failure(req.size());
782 result = allocate_memory_under_lock(req, in_new_region);
783 }
784
785 } else {
786 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
787 result = allocate_memory_under_lock(req, in_new_region);
788 // Do not call handle_alloc_failure() here, because we cannot block.
789 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
790 }
791
792 if (in_new_region) {
793 control_thread()->notify_heap_changed();
794 }
795
796 if (result != NULL) {
797 size_t requested = req.size();
798 size_t actual = req.actual_size();
799
800 assert (req.is_lab_alloc() || (requested == actual),
801 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
802 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
803
804 if (req.is_mutator_alloc()) {
805 notify_mutator_alloc_words(actual, false);
806
807 // If we requested more than we were granted, give the rest back to pacer.
808 // This only matters if we are in the same pacing epoch: do not try to unpace
809 // over the budget for the other phase.
810 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
811 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
812 }
813 } else {
814 increase_used(actual*HeapWordSize);
815 }
816 }
817
818 return result;
819 }
820
821 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
822 ShenandoahHeapLocker locker(lock());
823 return _free_set->allocate(req, in_new_region);
824 }
825
826 class ShenandoahMemAllocator : public MemAllocator {
827 private:
828 MemAllocator& _initializer;
829 public:
830 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
831 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
832 _initializer(initializer) {}
833
834 protected:
835 virtual HeapWord* mem_allocate(Allocation& allocation) const {
836 HeapWord* result = MemAllocator::mem_allocate(allocation);
837 // Initialize brooks-pointer
838 if (result != NULL) {
839 result += ShenandoahBrooksPointer::word_size();
840 ShenandoahBrooksPointer::initialize(oop(result));
841 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
842 }
843 return result;
844 }
845
846 virtual oop initialize(HeapWord* mem) const {
847 return _initializer.initialize(mem);
848 }
849 };
850
851 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
852 ObjAllocator initializer(klass, size, THREAD);
853 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
854 return allocator.allocate();
855 }
856
857 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
858 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
859 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
860 return allocator.allocate();
861 }
862
863 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
864 ClassAllocator initializer(klass, size, THREAD);
865 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
866 return allocator.allocate();
867 }
868
869 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
870 bool* gc_overhead_limit_was_exceeded) {
871 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
872 return allocate_memory(req);
873 }
874
875 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
876 size_t size,
877 Metaspace::MetadataType mdtype) {
878 MetaWord* result;
879
880 // Inform metaspace OOM to GC heuristics if class unloading is possible.
881 if (heuristics()->can_unload_classes()) {
882 ShenandoahHeuristics* h = heuristics();
883 h->record_metaspace_oom();
884 }
885
886 // Expand and retry allocation
887 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
888 if (result != NULL) {
889 return result;
890 }
891
892 // Start full GC
893 collect(GCCause::_metadata_GC_clear_soft_refs);
894
895 // Retry allocation
896 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
897 if (result != NULL) {
898 return result;
899 }
900
901 // Expand and retry allocation
902 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
903 if (result != NULL) {
904 return result;
905 }
906
907 // Out of memory
908 return NULL;
909 }
910
911 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
912 HeapWord* obj = tlab_post_allocation_setup(start);
913 CollectedHeap::fill_with_object(obj, end);
914 }
915
916 size_t ShenandoahHeap::min_dummy_object_size() const {
917 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
918 }
919
920 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
921 private:
922 ShenandoahHeap* _heap;
923 Thread* _thread;
924 public:
925 ShenandoahEvacuateUpdateRootsClosure() :
926 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
927 }
928
929 private:
930 template <class T>
931 void do_oop_work(T* p) {
932 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
933
934 T o = RawAccess<>::oop_load(p);
935 if (! CompressedOops::is_null(o)) {
936 oop obj = CompressedOops::decode_not_null(o);
937 if (_heap->in_collection_set(obj)) {
938 shenandoah_assert_marked(p, obj);
939 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
940 if (oopDesc::equals_raw(resolved, obj)) {
941 resolved = _heap->evacuate_object(obj, _thread);
942 }
943 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
944 }
945 }
946 }
947
948 public:
949 void do_oop(oop* p) {
950 do_oop_work(p);
951 }
952 void do_oop(narrowOop* p) {
953 do_oop_work(p);
954 }
955 };
956
957 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
958 private:
959 ShenandoahHeap* const _heap;
960 Thread* const _thread;
961 public:
962 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
963 _heap(heap), _thread(Thread::current()) {}
964
965 void do_object(oop p) {
966 shenandoah_assert_marked(NULL, p);
967 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
968 _heap->evacuate_object(p, _thread);
969 }
970 }
971 };
972
973 class ShenandoahEvacuationTask : public AbstractGangTask {
974 private:
975 ShenandoahHeap* const _sh;
976 ShenandoahCollectionSet* const _cs;
977 bool _concurrent;
978 public:
979 ShenandoahEvacuationTask(ShenandoahHeap* sh,
980 ShenandoahCollectionSet* cs,
981 bool concurrent) :
982 AbstractGangTask("Parallel Evacuation Task"),
983 _sh(sh),
984 _cs(cs),
985 _concurrent(concurrent)
986 {}
987
988 void work(uint worker_id) {
989 if (_concurrent) {
990 ShenandoahConcurrentWorkerSession worker_session(worker_id);
991 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
992 ShenandoahEvacOOMScope oom_evac_scope;
993 do_work();
994 } else {
995 ShenandoahParallelWorkerSession worker_session(worker_id);
996 ShenandoahEvacOOMScope oom_evac_scope;
997 do_work();
998 }
999 }
1000
1001 private:
1002 void do_work() {
1003 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
1004 ShenandoahHeapRegion* r;
1005 while ((r =_cs->claim_next()) != NULL) {
1006 assert(r->has_live(), "all-garbage regions are reclaimed early");
1007 _sh->marked_object_iterate(r, &cl);
1008
1009 if (ShenandoahPacing) {
1010 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1011 }
1012
1013 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
1014 break;
1015 }
1016 }
1017 }
1018 };
1019
1020 void ShenandoahHeap::trash_cset_regions() {
1021 ShenandoahHeapLocker locker(lock());
1022
1023 ShenandoahCollectionSet* set = collection_set();
1024 ShenandoahHeapRegion* r;
1025 set->clear_current_index();
1026 while ((r = set->next()) != NULL) {
1027 r->make_trash();
1028 }
1029 collection_set()->clear();
1030 }
1031
1032 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1033 st->print_cr("Heap Regions:");
1034 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1035 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1036 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1037 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1038
1039 for (size_t i = 0; i < num_regions(); i++) {
1040 get_region(i)->print_on(st);
1041 }
1042 }
1043
1044 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1045 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1046
1047 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
1048 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
1049 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1050 size_t index = start->region_number() + required_regions - 1;
1051
1052 assert(!start->has_live(), "liveness must be zero");
1053
1054 for(size_t i = 0; i < required_regions; i++) {
1055 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1056 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1057 ShenandoahHeapRegion* region = get_region(index --);
1058
1059 assert(region->is_humongous(), "expect correct humongous start or continuation");
1060 assert(!region->is_cset(), "Humongous region should not be in collection set");
1061
1062 region->make_trash_immediate();
1063 }
1064 }
1065
1066 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1067 public:
1068 void do_thread(Thread* thread) {
1069 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1070 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1071 gclab->retire();
1072 }
1073 };
1074
1075 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1076 if (UseTLAB) {
1077 CollectedHeap::ensure_parsability(retire_tlabs);
1078 }
1079 ShenandoahRetireGCLABClosure cl;
1080 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1081 cl.do_thread(t);
1082 }
1083 workers()->threads_do(&cl);
1084 }
1085
1086 void ShenandoahHeap::resize_tlabs() {
1087 CollectedHeap::resize_all_tlabs();
1088 }
1089
1090 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1091 private:
1092 ShenandoahRootEvacuator* _rp;
1093
1094 public:
1095 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1096 AbstractGangTask("Shenandoah evacuate and update roots"),
1097 _rp(rp) {}
1098
1099 void work(uint worker_id) {
1100 ShenandoahParallelWorkerSession worker_session(worker_id);
1101 ShenandoahEvacOOMScope oom_evac_scope;
1102 ShenandoahEvacuateUpdateRootsClosure cl;
1103 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1104 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1105 }
1106 };
1107
1108 void ShenandoahHeap::evacuate_and_update_roots() {
1109 #if defined(COMPILER2) || INCLUDE_JVMCI
1110 DerivedPointerTable::clear();
1111 #endif
1112 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1113
1114 {
1115 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1116 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1117 workers()->run_task(&roots_task);
1118 }
1119
1120 #if defined(COMPILER2) || INCLUDE_JVMCI
1121 DerivedPointerTable::update_pointers();
1122 #endif
1123 }
1124
1125 // Returns size in bytes
1126 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1127 if (ShenandoahElasticTLAB) {
1128 // With Elastic TLABs, return the max allowed size, and let the allocation path
1129 // figure out the safe size for current allocation.
1130 return ShenandoahHeapRegion::max_tlab_size_bytes();
1131 } else {
1132 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1133 }
1134 }
1135
1136 size_t ShenandoahHeap::max_tlab_size() const {
1137 // Returns size in words
1138 return ShenandoahHeapRegion::max_tlab_size_words();
1139 }
1140
1141 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1142 public:
1143 void do_thread(Thread* thread) {
1144 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1145 gclab->retire();
1146 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1147 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1148 }
1149 }
1150 };
1151
1152 void ShenandoahHeap::retire_and_reset_gclabs() {
1153 ShenandoahRetireAndResetGCLABClosure cl;
1154 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1155 cl.do_thread(t);
1156 }
1157 workers()->threads_do(&cl);
1158 }
1159
1160 void ShenandoahHeap::collect(GCCause::Cause cause) {
1161 control_thread()->request_gc(cause);
1162 }
1163
1164 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1165 //assert(false, "Shouldn't need to do full collections");
1166 }
1167
1168 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1169 return _shenandoah_policy;
1170 }
1171
1172 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1173 Space* sp = heap_region_containing(addr);
1174 if (sp != NULL) {
1175 return sp->block_start(addr);
1176 }
1177 return NULL;
1178 }
1179
1180 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1181 Space* sp = heap_region_containing(addr);
1182 return sp->block_is_obj(addr);
1183 }
1184
1185 jlong ShenandoahHeap::millis_since_last_gc() {
1186 double v = heuristics()->time_since_last_gc() * 1000;
1187 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1188 return (jlong)v;
1189 }
1190
1191 void ShenandoahHeap::prepare_for_verify() {
1192 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1193 make_parsable(false);
1194 }
1195 }
1196
1197 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1198 workers()->print_worker_threads_on(st);
1199 if (ShenandoahStringDedup::is_enabled()) {
1200 ShenandoahStringDedup::print_worker_threads_on(st);
1201 }
1202 }
1203
1204 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1205 workers()->threads_do(tcl);
1206 _safepoint_workers->threads_do(tcl);
1207 if (ShenandoahStringDedup::is_enabled()) {
1208 ShenandoahStringDedup::threads_do(tcl);
1209 }
1210 }
1211
1212 void ShenandoahHeap::print_tracing_info() const {
1213 LogTarget(Info, gc, stats) lt;
1214 if (lt.is_enabled()) {
1215 ResourceMark rm;
1216 LogStream ls(lt);
1217
1218 phase_timings()->print_on(&ls);
1219
1220 ls.cr();
1221 ls.cr();
1222
1223 shenandoah_policy()->print_gc_stats(&ls);
1224
1225 ls.cr();
1226 ls.cr();
1227
1228 if (ShenandoahPacing) {
1229 pacer()->print_on(&ls);
1230 }
1231
1232 ls.cr();
1233 ls.cr();
1234
1235 if (ShenandoahAllocationTrace) {
1236 assert(alloc_tracker() != NULL, "Must be");
1237 alloc_tracker()->print_on(&ls);
1238 } else {
1239 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1240 }
1241 }
1242 }
1243
1244 void ShenandoahHeap::verify(VerifyOption vo) {
1245 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1246 if (ShenandoahVerify) {
1247 verifier()->verify_generic(vo);
1248 } else {
1249 // TODO: Consider allocating verification bitmaps on demand,
1250 // and turn this on unconditionally.
1251 }
1252 }
1253 }
1254 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1255 return _free_set->capacity();
1256 }
1257
1258 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1259 private:
1260 MarkBitMap* _bitmap;
1261 Stack<oop,mtGC>* _oop_stack;
1262
1263 template <class T>
1264 void do_oop_work(T* p) {
1265 T o = RawAccess<>::oop_load(p);
1266 if (!CompressedOops::is_null(o)) {
1267 oop obj = CompressedOops::decode_not_null(o);
1268 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1269 assert(oopDesc::is_oop(obj), "must be a valid oop");
1270 if (!_bitmap->is_marked((HeapWord*) obj)) {
1271 _bitmap->mark((HeapWord*) obj);
1272 _oop_stack->push(obj);
1273 }
1274 }
1275 }
1276 public:
1277 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1278 _bitmap(bitmap), _oop_stack(oop_stack) {}
1279 void do_oop(oop* p) { do_oop_work(p); }
1280 void do_oop(narrowOop* p) { do_oop_work(p); }
1281 };
1282
1283 /*
1284 * This is public API, used in preparation of object_iterate().
1285 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1286 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1287 * control, we call SH::make_tlabs_parsable().
1288 */
1289 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1290 // No-op.
1291 }
1292
1293 /*
1294 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1295 *
1296 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1297 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1298 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1299 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1300 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1301 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1302 * wiped the bitmap in preparation for next marking).
1303 *
1304 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1305 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1306 * is allowed to report dead objects, but is not required to do so.
1307 */
1308 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1309 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1310 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1311 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1312 return;
1313 }
1314
1315 // Reset bitmap
1316 _aux_bit_map.clear();
1317
1318 Stack<oop,mtGC> oop_stack;
1319
1320 // First, we process all GC roots. This populates the work stack with initial objects.
1321 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1322 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1323 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1324 CodeBlobToOopClosure blobs(&oops, false);
1325 rp.process_all_roots(&oops, &clds, &blobs, NULL, 0);
1326
1327 // Work through the oop stack to traverse heap.
1328 while (! oop_stack.is_empty()) {
1329 oop obj = oop_stack.pop();
1330 assert(oopDesc::is_oop(obj), "must be a valid oop");
1331 cl->do_object(obj);
1332 obj->oop_iterate(&oops);
1333 }
1334
1335 assert(oop_stack.is_empty(), "should be empty");
1336
1337 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1338 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1339 }
1340 }
1341
1342 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1343 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1344 object_iterate(cl);
1345 }
1346
1347 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1348 for (size_t i = 0; i < num_regions(); i++) {
1349 ShenandoahHeapRegion* current = get_region(i);
1350 blk->heap_region_do(current);
1351 }
1352 }
1353
1354 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1355 private:
1356 ShenandoahHeap* const _heap;
1357 ShenandoahHeapRegionClosure* const _blk;
1358
1359 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1360 volatile size_t _index;
1361 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1362
1363 public:
1364 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1365 AbstractGangTask("Parallel Region Task"),
1366 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1367
1368 void work(uint worker_id) {
1369 size_t stride = ShenandoahParallelRegionStride;
1370
1371 size_t max = _heap->num_regions();
1372 while (_index < max) {
1373 size_t cur = Atomic::add(stride, &_index) - stride;
1374 size_t start = cur;
1375 size_t end = MIN2(cur + stride, max);
1376 if (start >= max) break;
1377
1378 for (size_t i = cur; i < end; i++) {
1379 ShenandoahHeapRegion* current = _heap->get_region(i);
1380 _blk->heap_region_do(current);
1381 }
1382 }
1383 }
1384 };
1385
1386 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1387 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1388 if (num_regions() > ShenandoahParallelRegionStride) {
1389 ShenandoahParallelHeapRegionTask task(blk);
1390 workers()->run_task(&task);
1391 } else {
1392 heap_region_iterate(blk);
1393 }
1394 }
1395
1396 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1397 private:
1398 ShenandoahMarkingContext* const _ctx;
1399 public:
1400 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1401
1402 void heap_region_do(ShenandoahHeapRegion* r) {
1403 if (r->is_active()) {
1404 r->clear_live_data();
1405 _ctx->capture_top_at_mark_start(r);
1406 } else {
1407 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1408 assert(_ctx->top_at_mark_start(r) == r->top(),
1409 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1410 }
1411 }
1412
1413 bool is_thread_safe() { return true; }
1414 };
1415
1416 void ShenandoahHeap::op_init_mark() {
1417 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1418 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1419
1420 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1421 assert(!marking_context()->is_complete(), "should not be complete");
1422
1423 if (ShenandoahVerify) {
1424 verifier()->verify_before_concmark();
1425 }
1426
1427 if (VerifyBeforeGC) {
1428 Universe::verify();
1429 }
1430
1431 set_concurrent_mark_in_progress(true);
1432 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1433 {
1434 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1435 make_parsable(true);
1436 }
1437
1438 {
1439 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1440 ShenandoahClearLivenessClosure clc;
1441 parallel_heap_region_iterate(&clc);
1442 }
1443
1444 // Make above changes visible to worker threads
1445 OrderAccess::fence();
1446
1447 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1448
1449 if (UseTLAB) {
1450 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1451 resize_tlabs();
1452 }
1453
1454 if (ShenandoahPacing) {
1455 pacer()->setup_for_mark();
1456 }
1457 }
1458
1459 void ShenandoahHeap::op_mark() {
1460 concurrent_mark()->mark_from_roots();
1461 }
1462
1463 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1464 private:
1465 ShenandoahMarkingContext* const _ctx;
1466 public:
1467 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1468
1469 void heap_region_do(ShenandoahHeapRegion* r) {
1470 if (r->is_active()) {
1471 HeapWord *tams = _ctx->top_at_mark_start(r);
1472 HeapWord *top = r->top();
1473 if (top > tams) {
1474 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1475 }
1476 } else {
1477 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1478 assert(_ctx->top_at_mark_start(r) == r->top(),
1479 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1480 }
1481 }
1482
1483 bool is_thread_safe() { return true; }
1484 };
1485
1486 void ShenandoahHeap::op_final_mark() {
1487 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1488
1489 // It is critical that we
1490 // evacuate roots right after finishing marking, so that we don't
1491 // get unmarked objects in the roots.
1492
1493 if (!cancelled_gc()) {
1494 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1495
1496 if (has_forwarded_objects()) {
1497 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1498 }
1499
1500 stop_concurrent_marking();
1501
1502 {
1503 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1504
1505 // All allocations past TAMS are implicitly live, adjust the region data.
1506 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1507 ShenandoahCompleteLivenessClosure cl;
1508 parallel_heap_region_iterate(&cl);
1509 }
1510
1511 {
1512 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1513
1514 make_parsable(true);
1515
1516 trash_cset_regions();
1517
1518 {
1519 ShenandoahHeapLocker locker(lock());
1520 _collection_set->clear();
1521 _free_set->clear();
1522
1523 heuristics()->choose_collection_set(_collection_set);
1524
1525 _free_set->rebuild();
1526 }
1527 }
1528
1529 // If collection set has candidates, start evacuation.
1530 // Otherwise, bypass the rest of the cycle.
1531 if (!collection_set()->is_empty()) {
1532 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1533
1534 if (ShenandoahVerify) {
1535 verifier()->verify_before_evacuation();
1536 }
1537
1538 set_evacuation_in_progress(true);
1539 // From here on, we need to update references.
1540 set_has_forwarded_objects(true);
1541
1542 evacuate_and_update_roots();
1543
1544 if (ShenandoahPacing) {
1545 pacer()->setup_for_evac();
1546 }
1547 } else {
1548 if (ShenandoahVerify) {
1549 verifier()->verify_after_concmark();
1550 }
1551
1552 if (VerifyAfterGC) {
1553 Universe::verify();
1554 }
1555 }
1556
1557 } else {
1558 concurrent_mark()->cancel();
1559 stop_concurrent_marking();
1560
1561 if (process_references()) {
1562 // Abandon reference processing right away: pre-cleaning must have failed.
1563 ReferenceProcessor *rp = ref_processor();
1564 rp->disable_discovery();
1565 rp->abandon_partial_discovery();
1566 rp->verify_no_references_recorded();
1567 }
1568 }
1569 }
1570
1571 void ShenandoahHeap::op_final_evac() {
1572 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1573
1574 set_evacuation_in_progress(false);
1575
1576 retire_and_reset_gclabs();
1577
1578 if (ShenandoahVerify) {
1579 verifier()->verify_after_evacuation();
1580 }
1581
1582 if (VerifyAfterGC) {
1583 Universe::verify();
1584 }
1585 }
1586
1587 void ShenandoahHeap::op_conc_evac() {
1588 ShenandoahEvacuationTask task(this, _collection_set, true);
1589 workers()->run_task(&task);
1590 }
1591
1592 void ShenandoahHeap::op_stw_evac() {
1593 ShenandoahEvacuationTask task(this, _collection_set, false);
1594 workers()->run_task(&task);
1595 }
1596
1597 void ShenandoahHeap::op_updaterefs() {
1598 update_heap_references(true);
1599 }
1600
1601 void ShenandoahHeap::op_cleanup() {
1602 free_set()->recycle_trash();
1603 }
1604
1605 void ShenandoahHeap::op_reset() {
1606 reset_mark_bitmap();
1607 }
1608
1609 void ShenandoahHeap::op_preclean() {
1610 concurrent_mark()->preclean_weak_refs();
1611 }
1612
1613 void ShenandoahHeap::op_init_traversal() {
1614 traversal_gc()->init_traversal_collection();
1615 }
1616
1617 void ShenandoahHeap::op_traversal() {
1618 traversal_gc()->concurrent_traversal_collection();
1619 }
1620
1621 void ShenandoahHeap::op_final_traversal() {
1622 traversal_gc()->final_traversal_collection();
1623 }
1624
1625 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1626 ShenandoahMetricsSnapshot metrics;
1627 metrics.snap_before();
1628
1629 full_gc()->do_it(cause);
1630 if (UseTLAB) {
1631 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1632 resize_all_tlabs();
1633 }
1634
1635 metrics.snap_after();
1636 metrics.print();
1637
1638 if (metrics.is_good_progress("Full GC")) {
1639 _progress_last_gc.set();
1640 } else {
1641 // Nothing to do. Tell the allocation path that we have failed to make
1642 // progress, and it can finally fail.
1643 _progress_last_gc.unset();
1644 }
1645 }
1646
1647 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1648 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1649 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1650 // some phase, we have to upgrade the Degenerate GC to Full GC.
1651
1652 clear_cancelled_gc();
1653
1654 ShenandoahMetricsSnapshot metrics;
1655 metrics.snap_before();
1656
1657 switch (point) {
1658 case _degenerated_traversal:
1659 {
1660 // Drop the collection set. Note: this leaves some already forwarded objects
1661 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1662 // workarounds in ShenandoahTraversalHeuristics.
1663
1664 ShenandoahHeapLocker locker(lock());
1665 collection_set()->clear_current_index();
1666 for (size_t i = 0; i < collection_set()->count(); i++) {
1667 ShenandoahHeapRegion* r = collection_set()->next();
1668 r->make_regular_bypass();
1669 }
1670 collection_set()->clear();
1671 }
1672 op_final_traversal();
1673 op_cleanup();
1674 return;
1675
1676 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1677 // but enters it at different points, depending on which concurrent phase had
1678 // degenerated.
1679
1680 case _degenerated_outside_cycle:
1681 // We have degenerated from outside the cycle, which means something is bad with
1682 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1683 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1684 // we can do the most aggressive degen cycle, which includes processing references and
1685 // class unloading, unless those features are explicitly disabled.
1686 //
1687 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1688 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1689 set_process_references(heuristics()->can_process_references());
1690 set_unload_classes(heuristics()->can_unload_classes());
1691
1692 if (heuristics()->can_do_traversal_gc()) {
1693 // Not possible to degenerate from here, upgrade to Full GC right away.
1694 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1695 op_degenerated_fail();
1696 return;
1697 }
1698
1699 op_reset();
1700
1701 op_init_mark();
1702 if (cancelled_gc()) {
1703 op_degenerated_fail();
1704 return;
1705 }
1706
1707 case _degenerated_mark:
1708 op_final_mark();
1709 if (cancelled_gc()) {
1710 op_degenerated_fail();
1711 return;
1712 }
1713
1714 op_cleanup();
1715
1716 case _degenerated_evac:
1717 // If heuristics thinks we should do the cycle, this flag would be set,
1718 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1719 if (is_evacuation_in_progress()) {
1720
1721 // Degeneration under oom-evac protocol might have left some objects in
1722 // collection set un-evacuated. Restart evacuation from the beginning to
1723 // capture all objects. For all the objects that are already evacuated,
1724 // it would be a simple check, which is supposed to be fast. This is also
1725 // safe to do even without degeneration, as CSet iterator is at beginning
1726 // in preparation for evacuation anyway.
1727 collection_set()->clear_current_index();
1728
1729 op_stw_evac();
1730 if (cancelled_gc()) {
1731 op_degenerated_fail();
1732 return;
1733 }
1734 }
1735
1736 // If heuristics thinks we should do the cycle, this flag would be set,
1737 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1738 if (has_forwarded_objects()) {
1739 op_init_updaterefs();
1740 if (cancelled_gc()) {
1741 op_degenerated_fail();
1742 return;
1743 }
1744 }
1745
1746 case _degenerated_updaterefs:
1747 if (has_forwarded_objects()) {
1748 op_final_updaterefs();
1749 if (cancelled_gc()) {
1750 op_degenerated_fail();
1751 return;
1752 }
1753 }
1754
1755 op_cleanup();
1756 break;
1757
1758 default:
1759 ShouldNotReachHere();
1760 }
1761
1762 if (ShenandoahVerify) {
1763 verifier()->verify_after_degenerated();
1764 }
1765
1766 if (VerifyAfterGC) {
1767 Universe::verify();
1768 }
1769
1770 metrics.snap_after();
1771 metrics.print();
1772
1773 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1774 // because that probably means the heap is overloaded and/or fragmented.
1775 if (!metrics.is_good_progress("Degenerated GC")) {
1776 _progress_last_gc.unset();
1777 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1778 op_degenerated_futile();
1779 } else {
1780 _progress_last_gc.set();
1781 }
1782 }
1783
1784 void ShenandoahHeap::op_degenerated_fail() {
1785 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1786 shenandoah_policy()->record_degenerated_upgrade_to_full();
1787 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1788 }
1789
1790 void ShenandoahHeap::op_degenerated_futile() {
1791 shenandoah_policy()->record_degenerated_upgrade_to_full();
1792 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1793 }
1794
1795 void ShenandoahHeap::stop_concurrent_marking() {
1796 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1797 if (!cancelled_gc()) {
1798 // If we needed to update refs, and concurrent marking has been cancelled,
1799 // we need to finish updating references.
1800 set_has_forwarded_objects(false);
1801 mark_complete_marking_context();
1802 }
1803 set_concurrent_mark_in_progress(false);
1804 }
1805
1806 void ShenandoahHeap::force_satb_flush_all_threads() {
1807 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1808 // No need to flush SATBs
1809 return;
1810 }
1811
1812 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1813 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1814 }
1815 // The threads are not "acquiring" their thread-local data, but it does not
1816 // hurt to "release" the updates here anyway.
1817 OrderAccess::fence();
1818 }
1819
1820 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1821 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1822 ShenandoahThreadLocalData::set_gc_state(t, state);
1823 }
1824 }
1825
1826 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1827 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1828 _gc_state.set_cond(mask, value);
1829 set_gc_state_all_threads(_gc_state.raw_value());
1830 }
1831
1832 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1833 set_gc_state_mask(MARKING, in_progress);
1834 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1835 }
1836
1837 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1838 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1839 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1840 }
1841
1842 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1843 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1844 set_gc_state_mask(EVACUATION, in_progress);
1845 }
1846
1847 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1848 // Initialize Brooks pointer for the next object
1849 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1850 ShenandoahBrooksPointer::initialize(oop(result));
1851 return result;
1852 }
1853
1854 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1855 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1856 }
1857
1858 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1859 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1860 }
1861
1862 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1863 if (CompressedOops::is_null(obj)) {
1864 return false;
1865 }
1866 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1867 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1868 return _mark_context->is_marked(obj);
1869 }
1870
1871 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1872 if (CompressedOops::is_null(obj)) {
1873 return false;
1874 }
1875 shenandoah_assert_not_forwarded(NULL, obj);
1876 return _mark_context->is_marked(obj);
1877 }
1878
1879 void ShenandoahHeap::ref_processing_init() {
1880 assert(_max_workers > 0, "Sanity");
1881
1882 _ref_processor =
1883 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1884 ParallelRefProcEnabled, // MT processing
1885 _max_workers, // Degree of MT processing
1886 true, // MT discovery
1887 _max_workers, // Degree of MT discovery
1888 false, // Reference discovery is not atomic
1889 NULL, // No closure, should be installed before use
1890 true); // Scale worker threads
1891
1892 shenandoah_assert_rp_isalive_not_installed();
1893 }
1894
1895 GCTracer* ShenandoahHeap::tracer() {
1896 return shenandoah_policy()->tracer();
1897 }
1898
1899 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1900 return _free_set->used();
1901 }
1902
1903 bool ShenandoahHeap::try_cancel_gc() {
1904 while (true) {
1905 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1906 if (prev == CANCELLABLE) return true;
1907 else if (prev == CANCELLED) return false;
1908 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1909 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1910 {
1911 // We need to provide a safepoint here, otherwise we might
1912 // spin forever if a SP is pending.
1913 ThreadBlockInVM sp(JavaThread::current());
1914 SpinPause();
1915 }
1916 }
1917 }
1918
1919 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1920 if (try_cancel_gc()) {
1921 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1922 log_info(gc)("%s", msg.buffer());
1923 Events::log(Thread::current(), "%s", msg.buffer());
1924 }
1925 }
1926
1927 uint ShenandoahHeap::max_workers() {
1928 return _max_workers;
1929 }
1930
1931 void ShenandoahHeap::stop() {
1932 // The shutdown sequence should be able to terminate when GC is running.
1933
1934 // Step 0. Notify policy to disable event recording.
1935 _shenandoah_policy->record_shutdown();
1936
1937 // Step 1. Notify control thread that we are in shutdown.
1938 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1939 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1940 control_thread()->prepare_for_graceful_shutdown();
1941
1942 // Step 2. Notify GC workers that we are cancelling GC.
1943 cancel_gc(GCCause::_shenandoah_stop_vm);
1944
1945 // Step 3. Wait until GC worker exits normally.
1946 control_thread()->stop();
1947
1948 // Step 4. Stop String Dedup thread if it is active
1949 if (ShenandoahStringDedup::is_enabled()) {
1950 ShenandoahStringDedup::stop();
1951 }
1952 }
1953
1954 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1955 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1956
1957 ShenandoahGCPhase root_phase(full_gc ?
1958 ShenandoahPhaseTimings::full_gc_purge :
1959 ShenandoahPhaseTimings::purge);
1960
1961 ShenandoahIsAliveSelector alive;
1962 BoolObjectClosure* is_alive = alive.is_alive_closure();
1963
1964 bool purged_class;
1965
1966 // Unload classes and purge SystemDictionary.
1967 {
1968 ShenandoahGCPhase phase(full_gc ?
1969 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1970 ShenandoahPhaseTimings::purge_class_unload);
1971 purged_class = SystemDictionary::do_unloading(gc_timer());
1972 }
1973
1974 {
1975 ShenandoahGCPhase phase(full_gc ?
1976 ShenandoahPhaseTimings::full_gc_purge_par :
1977 ShenandoahPhaseTimings::purge_par);
1978 uint active = _workers->active_workers();
1979 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1980 _workers->run_task(&unlink_task);
1981 }
1982
1983 {
1984 ShenandoahGCPhase phase(full_gc ?
1985 ShenandoahPhaseTimings::full_gc_purge_cldg :
1986 ShenandoahPhaseTimings::purge_cldg);
1987 ClassLoaderDataGraph::purge();
1988 }
1989 }
1990
1991 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1992 set_gc_state_mask(HAS_FORWARDED, cond);
1993 }
1994
1995 void ShenandoahHeap::set_process_references(bool pr) {
1996 _process_references.set_cond(pr);
1997 }
1998
1999 void ShenandoahHeap::set_unload_classes(bool uc) {
2000 _unload_classes.set_cond(uc);
2001 }
2002
2003 bool ShenandoahHeap::process_references() const {
2004 return _process_references.is_set();
2005 }
2006
2007 bool ShenandoahHeap::unload_classes() const {
2008 return _unload_classes.is_set();
2009 }
2010
2011 address ShenandoahHeap::in_cset_fast_test_addr() {
2012 ShenandoahHeap* heap = ShenandoahHeap::heap();
2013 assert(heap->collection_set() != NULL, "Sanity");
2014 return (address) heap->collection_set()->biased_map_address();
2015 }
2016
2017 address ShenandoahHeap::cancelled_gc_addr() {
2018 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2019 }
2020
2021 address ShenandoahHeap::gc_state_addr() {
2022 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2023 }
2024
2025 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2026 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2027 }
2028
2029 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2030 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2031 }
2032
2033 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2034 _degenerated_gc_in_progress.set_cond(in_progress);
2035 }
2036
2037 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2038 _full_gc_in_progress.set_cond(in_progress);
2039 }
2040
2041 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2042 assert (is_full_gc_in_progress(), "should be");
2043 _full_gc_move_in_progress.set_cond(in_progress);
2044 }
2045
2046 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2047 set_gc_state_mask(UPDATEREFS, in_progress);
2048 }
2049
2050 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2051 ShenandoahCodeRoots::add_nmethod(nm);
2052 }
2053
2054 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2055 ShenandoahCodeRoots::remove_nmethod(nm);
2056 }
2057
2058 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2059 ShenandoahHeapLocker locker(lock());
2060 heap_region_containing(o)->make_pinned();
2061 return o;
2062 }
2063
2064 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2065 ShenandoahHeapLocker locker(lock());
2066 heap_region_containing(o)->make_unpinned();
2067 }
2068
2069 GCTimer* ShenandoahHeap::gc_timer() const {
2070 return _gc_timer;
2071 }
2072
2073 #ifdef ASSERT
2074 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2075 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2076
2077 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2078 if (UseDynamicNumberOfGCThreads ||
2079 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2080 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2081 } else {
2082 // Use ParallelGCThreads inside safepoints
2083 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2084 }
2085 } else {
2086 if (UseDynamicNumberOfGCThreads ||
2087 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2088 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2089 } else {
2090 // Use ConcGCThreads outside safepoints
2091 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2092 }
2093 }
2094 }
2095 #endif
2096
2097 ShenandoahVerifier* ShenandoahHeap::verifier() {
2098 guarantee(ShenandoahVerify, "Should be enabled");
2099 assert (_verifier != NULL, "sanity");
2100 return _verifier;
2101 }
2102
2103 template<class T>
2104 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2105 private:
2106 T cl;
2107 ShenandoahHeap* _heap;
2108 ShenandoahRegionIterator* _regions;
2109 bool _concurrent;
2110 public:
2111 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2112 AbstractGangTask("Concurrent Update References Task"),
2113 cl(T()),
2114 _heap(ShenandoahHeap::heap()),
2115 _regions(regions),
2116 _concurrent(concurrent) {
2117 }
2118
2119 void work(uint worker_id) {
2120 if (_concurrent) {
2121 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2122 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2123 do_work();
2124 } else {
2125 ShenandoahParallelWorkerSession worker_session(worker_id);
2126 do_work();
2127 }
2128 }
2129
2130 private:
2131 void do_work() {
2132 ShenandoahHeapRegion* r = _regions->next();
2133 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2134 while (r != NULL) {
2135 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2136 assert (top_at_start_ur >= r->bottom(), "sanity");
2137 if (r->is_active() && !r->is_cset()) {
2138 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2139 }
2140 if (ShenandoahPacing) {
2141 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2142 }
2143 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2144 return;
2145 }
2146 r = _regions->next();
2147 }
2148 }
2149 };
2150
2151 void ShenandoahHeap::update_heap_references(bool concurrent) {
2152 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2153 workers()->run_task(&task);
2154 }
2155
2156 void ShenandoahHeap::op_init_updaterefs() {
2157 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2158
2159 set_evacuation_in_progress(false);
2160
2161 retire_and_reset_gclabs();
2162
2163 if (ShenandoahVerify) {
2164 verifier()->verify_before_updaterefs();
2165 }
2166
2167 set_update_refs_in_progress(true);
2168 make_parsable(true);
2169 for (uint i = 0; i < num_regions(); i++) {
2170 ShenandoahHeapRegion* r = get_region(i);
2171 r->set_concurrent_iteration_safe_limit(r->top());
2172 }
2173
2174 // Reset iterator.
2175 _update_refs_iterator.reset();
2176
2177 if (ShenandoahPacing) {
2178 pacer()->setup_for_updaterefs();
2179 }
2180 }
2181
2182 void ShenandoahHeap::op_final_updaterefs() {
2183 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2184
2185 // Check if there is left-over work, and finish it
2186 if (_update_refs_iterator.has_next()) {
2187 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2188
2189 // Finish updating references where we left off.
2190 clear_cancelled_gc();
2191 update_heap_references(false);
2192 }
2193
2194 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2195 // everything. On degenerated paths, cancelled gc would not be set anyway.
2196 if (cancelled_gc()) {
2197 clear_cancelled_gc();
2198 }
2199 assert(!cancelled_gc(), "Should have been done right before");
2200
2201 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2202 ShenandoahPhaseTimings::degen_gc_update_roots:
2203 ShenandoahPhaseTimings::final_update_refs_roots);
2204
2205 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2206
2207 trash_cset_regions();
2208 set_has_forwarded_objects(false);
2209 set_update_refs_in_progress(false);
2210
2211 if (ShenandoahVerify) {
2212 verifier()->verify_after_updaterefs();
2213 }
2214
2215 if (VerifyAfterGC) {
2216 Universe::verify();
2217 }
2218
2219 {
2220 ShenandoahHeapLocker locker(lock());
2221 _free_set->rebuild();
2222 }
2223 }
2224
2225 #ifdef ASSERT
2226 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2227 _lock.assert_owned_by_current_thread();
2228 }
2229
2230 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2231 _lock.assert_not_owned_by_current_thread();
2232 }
2233
2234 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2235 _lock.assert_owned_by_current_thread_or_safepoint();
2236 }
2237 #endif
2238
2239 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2240 print_on(st);
2241 print_heap_regions_on(st);
2242 }
2243
2244 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2245 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2246
2247 size_t regions_from = _bitmap_regions_per_slice * slice;
2248 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2249 for (size_t g = regions_from; g < regions_to; g++) {
2250 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2251 if (skip_self && g == r->region_number()) continue;
2252 if (get_region(g)->is_committed()) {
2253 return true;
2254 }
2255 }
2256 return false;
2257 }
2258
2259 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2260 assert_heaplock_owned_by_current_thread();
2261
2262 // Bitmaps in special regions do not need commits
2263 if (_bitmap_region_special) {
2264 return true;
2265 }
2266
2267 if (is_bitmap_slice_committed(r, true)) {
2268 // Some other region from the group is already committed, meaning the bitmap
2269 // slice is already committed, we exit right away.
2270 return true;
2271 }
2272
2273 // Commit the bitmap slice:
2274 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2275 size_t off = _bitmap_bytes_per_slice * slice;
2276 size_t len = _bitmap_bytes_per_slice;
2277 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2278 return false;
2279 }
2280 return true;
2281 }
2282
2283 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2284 assert_heaplock_owned_by_current_thread();
2285
2286 // Bitmaps in special regions do not need uncommits
2287 if (_bitmap_region_special) {
2288 return true;
2289 }
2290
2291 if (is_bitmap_slice_committed(r, true)) {
2292 // Some other region from the group is still committed, meaning the bitmap
2293 // slice is should stay committed, exit right away.
2294 return true;
2295 }
2296
2297 // Uncommit the bitmap slice:
2298 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2299 size_t off = _bitmap_bytes_per_slice * slice;
2300 size_t len = _bitmap_bytes_per_slice;
2301 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2302 return false;
2303 }
2304 return true;
2305 }
2306
2307 void ShenandoahHeap::safepoint_synchronize_begin() {
2308 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2309 SuspendibleThreadSet::synchronize();
2310 }
2311 }
2312
2313 void ShenandoahHeap::safepoint_synchronize_end() {
2314 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2315 SuspendibleThreadSet::desynchronize();
2316 }
2317 }
2318
2319 void ShenandoahHeap::vmop_entry_init_mark() {
2320 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2321 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2322 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2323
2324 try_inject_alloc_failure();
2325 VM_ShenandoahInitMark op;
2326 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2327 }
2328
2329 void ShenandoahHeap::vmop_entry_final_mark() {
2330 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2331 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2332 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2333
2334 try_inject_alloc_failure();
2335 VM_ShenandoahFinalMarkStartEvac op;
2336 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2337 }
2338
2339 void ShenandoahHeap::vmop_entry_final_evac() {
2340 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2341 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2342 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2343
2344 VM_ShenandoahFinalEvac op;
2345 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2346 }
2347
2348 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2349 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2350 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2351 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2352
2353 try_inject_alloc_failure();
2354 VM_ShenandoahInitUpdateRefs op;
2355 VMThread::execute(&op);
2356 }
2357
2358 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2359 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2360 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2361 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2362
2363 try_inject_alloc_failure();
2364 VM_ShenandoahFinalUpdateRefs op;
2365 VMThread::execute(&op);
2366 }
2367
2368 void ShenandoahHeap::vmop_entry_init_traversal() {
2369 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2370 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2371 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2372
2373 try_inject_alloc_failure();
2374 VM_ShenandoahInitTraversalGC op;
2375 VMThread::execute(&op);
2376 }
2377
2378 void ShenandoahHeap::vmop_entry_final_traversal() {
2379 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2380 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2381 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2382
2383 try_inject_alloc_failure();
2384 VM_ShenandoahFinalTraversalGC op;
2385 VMThread::execute(&op);
2386 }
2387
2388 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2389 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2390 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2391 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2392
2393 try_inject_alloc_failure();
2394 VM_ShenandoahFullGC op(cause);
2395 VMThread::execute(&op);
2396 }
2397
2398 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2399 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2400 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2401 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2402
2403 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2404 VMThread::execute(°enerated_gc);
2405 }
2406
2407 void ShenandoahHeap::entry_init_mark() {
2408 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2409 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2410 const char* msg = init_mark_event_message();
2411 GCTraceTime(Info, gc) time(msg, gc_timer());
2412 EventMark em("%s", msg);
2413
2414 ShenandoahWorkerScope scope(workers(),
2415 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2416 "init marking");
2417
2418 op_init_mark();
2419 }
2420
2421 void ShenandoahHeap::entry_final_mark() {
2422 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2423 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2424 const char* msg = final_mark_event_message();
2425 GCTraceTime(Info, gc) time(msg, gc_timer());
2426 EventMark em("%s", msg);
2427
2428 ShenandoahWorkerScope scope(workers(),
2429 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2430 "final marking");
2431
2432 op_final_mark();
2433 }
2434
2435 void ShenandoahHeap::entry_final_evac() {
2436 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2437 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2438 static const char* msg = "Pause Final Evac";
2439 GCTraceTime(Info, gc) time(msg, gc_timer());
2440 EventMark em("%s", msg);
2441
2442 op_final_evac();
2443 }
2444
2445 void ShenandoahHeap::entry_init_updaterefs() {
2446 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2447 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2448
2449 static const char* msg = "Pause Init Update Refs";
2450 GCTraceTime(Info, gc) time(msg, gc_timer());
2451 EventMark em("%s", msg);
2452
2453 // No workers used in this phase, no setup required
2454
2455 op_init_updaterefs();
2456 }
2457
2458 void ShenandoahHeap::entry_final_updaterefs() {
2459 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2460 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2461
2462 static const char* msg = "Pause Final Update Refs";
2463 GCTraceTime(Info, gc) time(msg, gc_timer());
2464 EventMark em("%s", msg);
2465
2466 ShenandoahWorkerScope scope(workers(),
2467 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2468 "final reference update");
2469
2470 op_final_updaterefs();
2471 }
2472
2473 void ShenandoahHeap::entry_init_traversal() {
2474 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2475 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2476
2477 static const char* msg = "Pause Init Traversal";
2478 GCTraceTime(Info, gc) time(msg, gc_timer());
2479 EventMark em("%s", msg);
2480
2481 ShenandoahWorkerScope scope(workers(),
2482 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2483 "init traversal");
2484
2485 op_init_traversal();
2486 }
2487
2488 void ShenandoahHeap::entry_final_traversal() {
2489 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2490 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2491
2492 static const char* msg = "Pause Final Traversal";
2493 GCTraceTime(Info, gc) time(msg, gc_timer());
2494 EventMark em("%s", msg);
2495
2496 ShenandoahWorkerScope scope(workers(),
2497 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2498 "final traversal");
2499
2500 op_final_traversal();
2501 }
2502
2503 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2504 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2505 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2506
2507 static const char* msg = "Pause Full";
2508 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2509 EventMark em("%s", msg);
2510
2511 ShenandoahWorkerScope scope(workers(),
2512 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2513 "full gc");
2514
2515 op_full(cause);
2516 }
2517
2518 void ShenandoahHeap::entry_degenerated(int point) {
2519 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2520 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2521
2522 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2523 const char* msg = degen_event_message(dpoint);
2524 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2525 EventMark em("%s", msg);
2526
2527 ShenandoahWorkerScope scope(workers(),
2528 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2529 "stw degenerated gc");
2530
2531 set_degenerated_gc_in_progress(true);
2532 op_degenerated(dpoint);
2533 set_degenerated_gc_in_progress(false);
2534 }
2535
2536 void ShenandoahHeap::entry_mark() {
2537 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2538
2539 const char* msg = conc_mark_event_message();
2540 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2541 EventMark em("%s", msg);
2542
2543 ShenandoahWorkerScope scope(workers(),
2544 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2545 "concurrent marking");
2546
2547 try_inject_alloc_failure();
2548 op_mark();
2549 }
2550
2551 void ShenandoahHeap::entry_evac() {
2552 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2553 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2554
2555 static const char* msg = "Concurrent evacuation";
2556 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2557 EventMark em("%s", msg);
2558
2559 ShenandoahWorkerScope scope(workers(),
2560 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2561 "concurrent evacuation");
2562
2563 try_inject_alloc_failure();
2564 op_conc_evac();
2565 }
2566
2567 void ShenandoahHeap::entry_updaterefs() {
2568 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2569
2570 static const char* msg = "Concurrent update references";
2571 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2572 EventMark em("%s", msg);
2573
2574 ShenandoahWorkerScope scope(workers(),
2575 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2576 "concurrent reference update");
2577
2578 try_inject_alloc_failure();
2579 op_updaterefs();
2580 }
2581 void ShenandoahHeap::entry_cleanup() {
2582 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2583
2584 static const char* msg = "Concurrent cleanup";
2585 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2586 EventMark em("%s", msg);
2587
2588 // This phase does not use workers, no need for setup
2589
2590 try_inject_alloc_failure();
2591 op_cleanup();
2592 }
2593
2594 void ShenandoahHeap::entry_reset() {
2595 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2596
2597 static const char* msg = "Concurrent reset";
2598 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2599 EventMark em("%s", msg);
2600
2601 ShenandoahWorkerScope scope(workers(),
2602 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2603 "concurrent reset");
2604
2605 try_inject_alloc_failure();
2606 op_reset();
2607 }
2608
2609 void ShenandoahHeap::entry_preclean() {
2610 if (ShenandoahPreclean && process_references()) {
2611 static const char* msg = "Concurrent precleaning";
2612 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2613 EventMark em("%s", msg);
2614
2615 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2616
2617 ShenandoahWorkerScope scope(workers(),
2618 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2619 "concurrent preclean",
2620 /* check_workers = */ false);
2621
2622 try_inject_alloc_failure();
2623 op_preclean();
2624 }
2625 }
2626
2627 void ShenandoahHeap::entry_traversal() {
2628 static const char* msg = "Concurrent traversal";
2629 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2630 EventMark em("%s", msg);
2631
2632 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2633
2634 ShenandoahWorkerScope scope(workers(),
2635 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2636 "concurrent traversal");
2637
2638 try_inject_alloc_failure();
2639 op_traversal();
2640 }
2641
2642 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2643 static const char *msg = "Concurrent uncommit";
2644 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2645 EventMark em("%s", msg);
2646
2647 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2648
2649 op_uncommit(shrink_before);
2650 }
2651
2652 void ShenandoahHeap::try_inject_alloc_failure() {
2653 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2654 _inject_alloc_failure.set();
2655 os::naked_short_sleep(1);
2656 if (cancelled_gc()) {
2657 log_info(gc)("Allocation failure was successfully injected");
2658 }
2659 }
2660 }
2661
2662 bool ShenandoahHeap::should_inject_alloc_failure() {
2663 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2664 }
2665
2666 void ShenandoahHeap::initialize_serviceability() {
2667 _memory_pool = new ShenandoahMemoryPool(this);
2668 _cycle_memory_manager.add_pool(_memory_pool);
2669 _stw_memory_manager.add_pool(_memory_pool);
2670 }
2671
2672 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2673 GrowableArray<GCMemoryManager*> memory_managers(2);
2674 memory_managers.append(&_cycle_memory_manager);
2675 memory_managers.append(&_stw_memory_manager);
2676 return memory_managers;
2677 }
2678
2679 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2680 GrowableArray<MemoryPool*> memory_pools(1);
2681 memory_pools.append(_memory_pool);
2682 return memory_pools;
2683 }
2684
2685 MemoryUsage ShenandoahHeap::memory_usage() {
2686 return _memory_pool->get_memory_usage();
2687 }
2688
2689 void ShenandoahHeap::enter_evacuation() {
2690 _oom_evac_handler.enter_evacuation();
2691 }
2692
2693 void ShenandoahHeap::leave_evacuation() {
2694 _oom_evac_handler.leave_evacuation();
2695 }
2696
2697 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2698 _heap(ShenandoahHeap::heap()),
2699 _index(0) {}
2700
2701 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2702 _heap(heap),
2703 _index(0) {}
2704
2705 void ShenandoahRegionIterator::reset() {
2706 _index = 0;
2707 }
2708
2709 bool ShenandoahRegionIterator::has_next() const {
2710 return _index < _heap->num_regions();
2711 }
2712
2713 char ShenandoahHeap::gc_state() const {
2714 return _gc_state.raw_value();
2715 }
2716
2717 void ShenandoahHeap::deduplicate_string(oop str) {
2718 assert(java_lang_String::is_instance(str), "invariant");
2719
2720 if (ShenandoahStringDedup::is_enabled()) {
2721 ShenandoahStringDedup::deduplicate(str);
2722 }
2723 }
2724
2725 const char* ShenandoahHeap::init_mark_event_message() const {
2726 bool update_refs = has_forwarded_objects();
2727 bool proc_refs = process_references();
2728 bool unload_cls = unload_classes();
2729
2730 if (update_refs && proc_refs && unload_cls) {
2731 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2732 } else if (update_refs && proc_refs) {
2733 return "Pause Init Mark (update refs) (process weakrefs)";
2734 } else if (update_refs && unload_cls) {
2735 return "Pause Init Mark (update refs) (unload classes)";
2736 } else if (proc_refs && unload_cls) {
2737 return "Pause Init Mark (process weakrefs) (unload classes)";
2738 } else if (update_refs) {
2739 return "Pause Init Mark (update refs)";
2740 } else if (proc_refs) {
2741 return "Pause Init Mark (process weakrefs)";
2742 } else if (unload_cls) {
2743 return "Pause Init Mark (unload classes)";
2744 } else {
2745 return "Pause Init Mark";
2746 }
2747 }
2748
2749 const char* ShenandoahHeap::final_mark_event_message() const {
2750 bool update_refs = has_forwarded_objects();
2751 bool proc_refs = process_references();
2752 bool unload_cls = unload_classes();
2753
2754 if (update_refs && proc_refs && unload_cls) {
2755 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2756 } else if (update_refs && proc_refs) {
2757 return "Pause Final Mark (update refs) (process weakrefs)";
2758 } else if (update_refs && unload_cls) {
2759 return "Pause Final Mark (update refs) (unload classes)";
2760 } else if (proc_refs && unload_cls) {
2761 return "Pause Final Mark (process weakrefs) (unload classes)";
2762 } else if (update_refs) {
2763 return "Pause Final Mark (update refs)";
2764 } else if (proc_refs) {
2765 return "Pause Final Mark (process weakrefs)";
2766 } else if (unload_cls) {
2767 return "Pause Final Mark (unload classes)";
2768 } else {
2769 return "Pause Final Mark";
2770 }
2771 }
2772
2773 const char* ShenandoahHeap::conc_mark_event_message() const {
2774 bool update_refs = has_forwarded_objects();
2775 bool proc_refs = process_references();
2776 bool unload_cls = unload_classes();
2777
2778 if (update_refs && proc_refs && unload_cls) {
2779 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2780 } else if (update_refs && proc_refs) {
2781 return "Concurrent marking (update refs) (process weakrefs)";
2782 } else if (update_refs && unload_cls) {
2783 return "Concurrent marking (update refs) (unload classes)";
2784 } else if (proc_refs && unload_cls) {
2785 return "Concurrent marking (process weakrefs) (unload classes)";
2786 } else if (update_refs) {
2787 return "Concurrent marking (update refs)";
2788 } else if (proc_refs) {
2789 return "Concurrent marking (process weakrefs)";
2790 } else if (unload_cls) {
2791 return "Concurrent marking (unload classes)";
2792 } else {
2793 return "Concurrent marking";
2794 }
2795 }
2796
2797 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2798 switch (point) {
2799 case _degenerated_unset:
2800 return "Pause Degenerated GC (<UNSET>)";
2801 case _degenerated_traversal:
2802 return "Pause Degenerated GC (Traversal)";
2803 case _degenerated_outside_cycle:
2804 return "Pause Degenerated GC (Outside of Cycle)";
2805 case _degenerated_mark:
2806 return "Pause Degenerated GC (Mark)";
2807 case _degenerated_evac:
2808 return "Pause Degenerated GC (Evacuation)";
2809 case _degenerated_updaterefs:
2810 return "Pause Degenerated GC (Update Refs)";
2811 default:
2812 ShouldNotReachHere();
2813 return "ERROR";
2814 }
2815 }
2816
2817 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2818 #ifdef ASSERT
2819 assert(_liveness_cache != NULL, "sanity");
2820 assert(worker_id < _max_workers, "sanity");
2821 for (uint i = 0; i < num_regions(); i++) {
2822 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2823 }
2824 #endif
2825 return _liveness_cache[worker_id];
2826 }
2827
2828 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2829 assert(worker_id < _max_workers, "sanity");
2830 assert(_liveness_cache != NULL, "sanity");
2831 jushort* ld = _liveness_cache[worker_id];
2832 for (uint i = 0; i < num_regions(); i++) {
2833 ShenandoahHeapRegion* r = get_region(i);
2834 jushort live = ld[i];
2835 if (live > 0) {
2836 r->increase_live_data_gc_words(live);
2837 ld[i] = 0;
2838 }
2839 }
2840 }
2841
2842 size_t ShenandoahHeap::obj_size(oop obj) const {
2843 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2844 }
2845
2846 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2847 return ShenandoahBrooksPointer::byte_size();
2848 }
2849
2850 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2851 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2852 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2853 }