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
393 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
394 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
395 }
396 log_info(gc, init)("Shenandoah heuristics: %s",
397 _heuristics->name());
398 } else {
399 ShouldNotReachHere();
400 }
401
402 }
403
404 #ifdef _MSC_VER
405 #pragma warning( push )
406 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
407 #endif
408
409 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
410 CollectedHeap(),
411 _initial_size(0),
412 _used(0),
413 _committed(0),
414 _bytes_allocated_since_gc_start(0),
415 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
416 _workers(NULL),
417 _safepoint_workers(NULL),
418 _heap_region_special(false),
419 _num_regions(0),
420 _regions(NULL),
421 _update_refs_iterator(this),
422 _control_thread(NULL),
423 _shenandoah_policy(policy),
424 _heuristics(NULL),
425 _free_set(NULL),
426 _scm(new ShenandoahConcurrentMark()),
427 _traversal_gc(NULL),
428 _full_gc(new ShenandoahMarkCompact()),
429 _pacer(NULL),
430 _verifier(NULL),
431 _alloc_tracker(NULL),
432 _phase_timings(NULL),
433 _monitoring_support(NULL),
434 _memory_pool(NULL),
435 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
436 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
437 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
438 _soft_ref_policy(),
439 _ref_processor(NULL),
440 _marking_context(NULL),
441 _bitmap_size(0),
442 _bitmap_regions_per_slice(0),
443 _bitmap_bytes_per_slice(0),
444 _bitmap_region_special(false),
445 _aux_bitmap_region_special(false),
446 _liveness_cache(NULL),
447 _collection_set(NULL)
448 {
449 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
450 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
451
452 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
453
454 _max_workers = MAX2(_max_workers, 1U);
455 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
456 /* are_GC_task_threads */true,
457 /* are_ConcurrentGC_threads */false);
458 if (_workers == NULL) {
459 vm_exit_during_initialization("Failed necessary allocation.");
460 } else {
461 _workers->initialize_workers();
462 }
463
464 if (ShenandoahParallelSafepointThreads > 1) {
465 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
466 ShenandoahParallelSafepointThreads,
467 false, false);
468 _safepoint_workers->initialize_workers();
469 }
470 }
471
472 #ifdef _MSC_VER
473 #pragma warning( pop )
474 #endif
475
476 class ShenandoahResetBitmapTask : public AbstractGangTask {
477 private:
478 ShenandoahRegionIterator _regions;
479
480 public:
481 ShenandoahResetBitmapTask() :
482 AbstractGangTask("Parallel Reset Bitmap Task") {}
483
484 void work(uint worker_id) {
485 ShenandoahHeapRegion* region = _regions.next();
486 ShenandoahHeap* heap = ShenandoahHeap::heap();
487 ShenandoahMarkingContext* const ctx = heap->marking_context();
488 while (region != NULL) {
489 if (heap->is_bitmap_slice_committed(region)) {
490 ctx->clear_bitmap(region);
491 }
492 region = _regions.next();
493 }
494 }
495 };
496
497 void ShenandoahHeap::reset_mark_bitmap() {
498 assert_gc_workers(_workers->active_workers());
499 mark_incomplete_marking_context();
500
501 ShenandoahResetBitmapTask task;
502 _workers->run_task(&task);
503 }
504
505 void ShenandoahHeap::print_on(outputStream* st) const {
506 st->print_cr("Shenandoah Heap");
507 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
508 capacity() / K, committed() / K, used() / K);
509 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
510 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
511
512 st->print("Status: ");
513 if (has_forwarded_objects()) st->print("has forwarded objects, ");
514 if (is_concurrent_mark_in_progress()) st->print("marking, ");
515 if (is_evacuation_in_progress()) st->print("evacuating, ");
516 if (is_update_refs_in_progress()) st->print("updating refs, ");
517 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
518 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
519 if (is_full_gc_in_progress()) st->print("full gc, ");
520 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
521
522 if (cancelled_gc()) {
523 st->print("cancelled");
524 } else {
525 st->print("not cancelled");
526 }
527 st->cr();
528
529 st->print_cr("Reserved region:");
530 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
531 p2i(reserved_region().start()),
532 p2i(reserved_region().end()));
533
534 st->cr();
535 MetaspaceUtils::print_on(st);
536
537 if (Verbose) {
538 print_heap_regions_on(st);
539 }
540 }
541
542 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
543 public:
544 void do_thread(Thread* thread) {
545 assert(thread != NULL, "Sanity");
546 assert(thread->is_Worker_thread(), "Only worker thread expected");
547 ShenandoahThreadLocalData::initialize_gclab(thread);
548 }
549 };
550
551 void ShenandoahHeap::post_initialize() {
552 CollectedHeap::post_initialize();
553 MutexLocker ml(Threads_lock);
554
555 ShenandoahInitWorkerGCLABClosure init_gclabs;
556 _workers->threads_do(&init_gclabs);
557
558 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
559 // Now, we will let WorkGang to initialize gclab when new worker is created.
560 _workers->set_initialize_gclab();
561
562 _scm->initialize(_max_workers);
563 _full_gc->initialize(_gc_timer);
564
565 ref_processing_init();
566
567 _heuristics->initialize();
568 }
569
570 size_t ShenandoahHeap::used() const {
571 return OrderAccess::load_acquire(&_used);
572 }
573
574 size_t ShenandoahHeap::committed() const {
575 OrderAccess::acquire();
576 return _committed;
577 }
578
579 void ShenandoahHeap::increase_committed(size_t bytes) {
580 assert_heaplock_or_safepoint();
581 _committed += bytes;
582 }
583
584 void ShenandoahHeap::decrease_committed(size_t bytes) {
585 assert_heaplock_or_safepoint();
586 _committed -= bytes;
587 }
588
589 void ShenandoahHeap::increase_used(size_t bytes) {
590 Atomic::add(bytes, &_used);
591 }
592
593 void ShenandoahHeap::set_used(size_t bytes) {
594 OrderAccess::release_store_fence(&_used, bytes);
595 }
596
597 void ShenandoahHeap::decrease_used(size_t bytes) {
598 assert(used() >= bytes, "never decrease heap size by more than we've left");
599 Atomic::sub(bytes, &_used);
600 }
601
602 void ShenandoahHeap::increase_allocated(size_t bytes) {
603 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
604 }
605
606 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
607 size_t bytes = words * HeapWordSize;
608 if (!waste) {
609 increase_used(bytes);
610 }
611 increase_allocated(bytes);
612 if (ShenandoahPacing) {
613 control_thread()->pacing_notify_alloc(words);
614 if (waste) {
615 pacer()->claim_for_alloc(words, true);
616 }
617 }
618 }
619
620 size_t ShenandoahHeap::capacity() const {
621 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
622 }
623
624 size_t ShenandoahHeap::max_capacity() const {
625 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
626 }
627
628 size_t ShenandoahHeap::initial_capacity() const {
629 return _initial_size;
630 }
631
632 bool ShenandoahHeap::is_in(const void* p) const {
633 HeapWord* heap_base = (HeapWord*) base();
634 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
635 return p >= heap_base && p < last_region_end;
636 }
637
638 void ShenandoahHeap::op_uncommit(double shrink_before) {
639 assert (ShenandoahUncommit, "should be enabled");
640
641 size_t count = 0;
642 for (size_t i = 0; i < num_regions(); i++) {
643 ShenandoahHeapRegion* r = get_region(i);
644 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
645 ShenandoahHeapLocker locker(lock());
646 if (r->is_empty_committed()) {
647 r->make_uncommitted();
648 count++;
649 }
650 }
651 SpinPause(); // allow allocators to take the lock
652 }
653
654 if (count > 0) {
655 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
656 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
657 control_thread()->notify_heap_changed();
658 }
659 }
660
661 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
662 // New object should fit the GCLAB size
663 size_t min_size = MAX2(size, PLAB::min_size());
664
665 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
666 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
667 new_size = MIN2(new_size, PLAB::max_size());
668 new_size = MAX2(new_size, PLAB::min_size());
669
670 // Record new heuristic value even if we take any shortcut. This captures
671 // the case when moderately-sized objects always take a shortcut. At some point,
672 // heuristics should catch up with them.
673 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
674
675 if (new_size < size) {
676 // New size still does not fit the object. Fall back to shared allocation.
677 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
678 return NULL;
679 }
680
681 // Retire current GCLAB, and allocate a new one.
682 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
683 gclab->retire();
684
685 size_t actual_size = 0;
686 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
687 if (gclab_buf == NULL) {
688 return NULL;
689 }
690
691 assert (size <= actual_size, "allocation should fit");
692
693 if (ZeroTLAB) {
694 // ..and clear it.
695 Copy::zero_to_words(gclab_buf, actual_size);
696 } else {
697 // ...and zap just allocated object.
698 #ifdef ASSERT
699 // Skip mangling the space corresponding to the object header to
700 // ensure that the returned space is not considered parsable by
701 // any concurrent GC thread.
702 size_t hdr_size = oopDesc::header_size();
703 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
704 #endif // ASSERT
705 }
706 gclab->set_buf(gclab_buf, actual_size);
707 return gclab->allocate(size);
708 }
709
710 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
711 size_t requested_size,
712 size_t* actual_size) {
713 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
714 HeapWord* res = allocate_memory(req);
715 if (res != NULL) {
716 *actual_size = req.actual_size();
717 } else {
718 *actual_size = 0;
719 }
720 return res;
721 }
722
723 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
724 size_t word_size,
725 size_t* actual_size) {
726 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
727 HeapWord* res = allocate_memory(req);
728 if (res != NULL) {
729 *actual_size = req.actual_size();
730 } else {
731 *actual_size = 0;
732 }
733 return res;
734 }
735
736 ShenandoahHeap* ShenandoahHeap::heap() {
737 CollectedHeap* heap = Universe::heap();
738 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
739 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
740 return (ShenandoahHeap*) heap;
741 }
742
743 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
744 CollectedHeap* heap = Universe::heap();
745 return (ShenandoahHeap*) heap;
746 }
747
748 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
749 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
750
751 intptr_t pacer_epoch = 0;
752 bool in_new_region = false;
753 HeapWord* result = NULL;
754
755 if (req.is_mutator_alloc()) {
756 if (ShenandoahPacing) {
757 pacer()->pace_for_alloc(req.size());
758 pacer_epoch = pacer()->epoch();
759 }
760
761 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
762 result = allocate_memory_under_lock(req, in_new_region);
763 }
764
765 // Allocation failed, block until control thread reacted, then retry allocation.
766 //
767 // It might happen that one of the threads requesting allocation would unblock
768 // way later after GC happened, only to fail the second allocation, because
769 // other threads have already depleted the free storage. In this case, a better
770 // strategy is to try again, as long as GC makes progress.
771 //
772 // Then, we need to make sure the allocation was retried after at least one
773 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
774
775 size_t tries = 0;
776
777 while (result == NULL && _progress_last_gc.is_set()) {
778 tries++;
779 control_thread()->handle_alloc_failure(req.size());
780 result = allocate_memory_under_lock(req, in_new_region);
781 }
782
783 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
784 tries++;
785 control_thread()->handle_alloc_failure(req.size());
786 result = allocate_memory_under_lock(req, in_new_region);
787 }
788
789 } else {
790 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
791 result = allocate_memory_under_lock(req, in_new_region);
792 // Do not call handle_alloc_failure() here, because we cannot block.
793 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
794 }
795
796 if (in_new_region) {
797 control_thread()->notify_heap_changed();
798 }
799
800 if (result != NULL) {
801 size_t requested = req.size();
802 size_t actual = req.actual_size();
803
804 assert (req.is_lab_alloc() || (requested == actual),
805 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
806 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
807
808 if (req.is_mutator_alloc()) {
809 notify_mutator_alloc_words(actual, false);
810
811 // If we requested more than we were granted, give the rest back to pacer.
812 // This only matters if we are in the same pacing epoch: do not try to unpace
813 // over the budget for the other phase.
814 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
815 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
816 }
817 } else {
818 increase_used(actual*HeapWordSize);
819 }
820 }
821
822 return result;
823 }
824
825 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
826 ShenandoahHeapLocker locker(lock());
827 return _free_set->allocate(req, in_new_region);
828 }
829
830 class ShenandoahMemAllocator : public MemAllocator {
831 private:
832 MemAllocator& _initializer;
833 public:
834 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
835 MemAllocator(klass, word_size + ShenandoahBrooksPointer::word_size(), thread),
836 _initializer(initializer) {}
837
838 protected:
839 virtual HeapWord* mem_allocate(Allocation& allocation) const {
840 HeapWord* result = MemAllocator::mem_allocate(allocation);
841 // Initialize brooks-pointer
842 if (result != NULL) {
843 result += ShenandoahBrooksPointer::word_size();
844 ShenandoahBrooksPointer::initialize(oop(result));
845 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
846 }
847 return result;
848 }
849
850 virtual oop initialize(HeapWord* mem) const {
851 return _initializer.initialize(mem);
852 }
853 };
854
855 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
856 ObjAllocator initializer(klass, size, THREAD);
857 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
858 return allocator.allocate();
859 }
860
861 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
862 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
863 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
864 return allocator.allocate();
865 }
866
867 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
868 ClassAllocator initializer(klass, size, THREAD);
869 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
870 return allocator.allocate();
871 }
872
873 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
874 bool* gc_overhead_limit_was_exceeded) {
875 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
876 return allocate_memory(req);
877 }
878
879 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
880 size_t size,
881 Metaspace::MetadataType mdtype) {
882 MetaWord* result;
883
884 // Inform metaspace OOM to GC heuristics if class unloading is possible.
885 if (heuristics()->can_unload_classes()) {
886 ShenandoahHeuristics* h = heuristics();
887 h->record_metaspace_oom();
888 }
889
890 // Expand and retry allocation
891 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
892 if (result != NULL) {
893 return result;
894 }
895
896 // Start full GC
897 collect(GCCause::_metadata_GC_clear_soft_refs);
898
899 // Retry allocation
900 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
901 if (result != NULL) {
902 return result;
903 }
904
905 // Expand and retry allocation
906 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
907 if (result != NULL) {
908 return result;
909 }
910
911 // Out of memory
912 return NULL;
913 }
914
915 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
916 HeapWord* obj = tlab_post_allocation_setup(start);
917 CollectedHeap::fill_with_object(obj, end);
918 }
919
920 size_t ShenandoahHeap::min_dummy_object_size() const {
921 return CollectedHeap::min_dummy_object_size() + ShenandoahBrooksPointer::word_size();
922 }
923
924 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
925 private:
926 ShenandoahHeap* _heap;
927 Thread* _thread;
928 public:
929 ShenandoahEvacuateUpdateRootsClosure() :
930 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
931 }
932
933 private:
934 template <class T>
935 void do_oop_work(T* p) {
936 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
937
938 T o = RawAccess<>::oop_load(p);
939 if (! CompressedOops::is_null(o)) {
940 oop obj = CompressedOops::decode_not_null(o);
941 if (_heap->in_collection_set(obj)) {
942 shenandoah_assert_marked(p, obj);
943 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
944 if (oopDesc::equals_raw(resolved, obj)) {
945 resolved = _heap->evacuate_object(obj, _thread);
946 }
947 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
948 }
949 }
950 }
951
952 public:
953 void do_oop(oop* p) {
954 do_oop_work(p);
955 }
956 void do_oop(narrowOop* p) {
957 do_oop_work(p);
958 }
959 };
960
961 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
962 private:
963 ShenandoahHeap* const _heap;
964 Thread* const _thread;
965 public:
966 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
967 _heap(heap), _thread(Thread::current()) {}
968
969 void do_object(oop p) {
970 shenandoah_assert_marked(NULL, p);
971 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
972 _heap->evacuate_object(p, _thread);
973 }
974 }
975 };
976
977 class ShenandoahEvacuationTask : public AbstractGangTask {
978 private:
979 ShenandoahHeap* const _sh;
980 ShenandoahCollectionSet* const _cs;
981 bool _concurrent;
982 public:
983 ShenandoahEvacuationTask(ShenandoahHeap* sh,
984 ShenandoahCollectionSet* cs,
985 bool concurrent) :
986 AbstractGangTask("Parallel Evacuation Task"),
987 _sh(sh),
988 _cs(cs),
989 _concurrent(concurrent)
990 {}
991
992 void work(uint worker_id) {
993 if (_concurrent) {
994 ShenandoahConcurrentWorkerSession worker_session(worker_id);
995 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
996 ShenandoahEvacOOMScope oom_evac_scope;
997 do_work();
998 } else {
999 ShenandoahParallelWorkerSession worker_session(worker_id);
1000 ShenandoahEvacOOMScope oom_evac_scope;
1001 do_work();
1002 }
1003 }
1004
1005 private:
1006 void do_work() {
1007 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
1008 ShenandoahHeapRegion* r;
1009 while ((r =_cs->claim_next()) != NULL) {
1010 assert(r->has_live(), "all-garbage regions are reclaimed early");
1011 _sh->marked_object_iterate(r, &cl);
1012
1013 if (ShenandoahPacing) {
1014 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1015 }
1016
1017 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
1018 break;
1019 }
1020 }
1021 }
1022 };
1023
1024 void ShenandoahHeap::trash_cset_regions() {
1025 ShenandoahHeapLocker locker(lock());
1026
1027 ShenandoahCollectionSet* set = collection_set();
1028 ShenandoahHeapRegion* r;
1029 set->clear_current_index();
1030 while ((r = set->next()) != NULL) {
1031 r->make_trash();
1032 }
1033 collection_set()->clear();
1034 }
1035
1036 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1037 st->print_cr("Heap Regions:");
1038 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1039 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1040 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1041 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1042
1043 for (size_t i = 0; i < num_regions(); i++) {
1044 get_region(i)->print_on(st);
1045 }
1046 }
1047
1048 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1049 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1050
1051 oop humongous_obj = oop(start->bottom() + ShenandoahBrooksPointer::word_size());
1052 size_t size = humongous_obj->size() + ShenandoahBrooksPointer::word_size();
1053 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1054 size_t index = start->region_number() + required_regions - 1;
1055
1056 assert(!start->has_live(), "liveness must be zero");
1057
1058 for(size_t i = 0; i < required_regions; i++) {
1059 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1060 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1061 ShenandoahHeapRegion* region = get_region(index --);
1062
1063 assert(region->is_humongous(), "expect correct humongous start or continuation");
1064 assert(!region->is_cset(), "Humongous region should not be in collection set");
1065
1066 region->make_trash_immediate();
1067 }
1068 }
1069
1070 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1071 public:
1072 void do_thread(Thread* thread) {
1073 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1074 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1075 gclab->retire();
1076 }
1077 };
1078
1079 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1080 if (UseTLAB) {
1081 CollectedHeap::ensure_parsability(retire_tlabs);
1082 }
1083 ShenandoahRetireGCLABClosure cl;
1084 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1085 cl.do_thread(t);
1086 }
1087 workers()->threads_do(&cl);
1088 }
1089
1090 void ShenandoahHeap::resize_tlabs() {
1091 CollectedHeap::resize_all_tlabs();
1092 }
1093
1094 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1095 private:
1096 ShenandoahRootEvacuator* _rp;
1097
1098 public:
1099 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1100 AbstractGangTask("Shenandoah evacuate and update roots"),
1101 _rp(rp) {}
1102
1103 void work(uint worker_id) {
1104 ShenandoahParallelWorkerSession worker_session(worker_id);
1105 ShenandoahEvacOOMScope oom_evac_scope;
1106 ShenandoahEvacuateUpdateRootsClosure cl;
1107
1108 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1109 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1110 }
1111 };
1112
1113 void ShenandoahHeap::evacuate_and_update_roots() {
1114 #if defined(COMPILER2) || INCLUDE_JVMCI
1115 DerivedPointerTable::clear();
1116 #endif
1117 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1118
1119 {
1120 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1121 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1122 workers()->run_task(&roots_task);
1123 }
1124
1125 #if defined(COMPILER2) || INCLUDE_JVMCI
1126 DerivedPointerTable::update_pointers();
1127 #endif
1128 }
1129
1130 // Returns size in bytes
1131 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1132 if (ShenandoahElasticTLAB) {
1133 // With Elastic TLABs, return the max allowed size, and let the allocation path
1134 // figure out the safe size for current allocation.
1135 return ShenandoahHeapRegion::max_tlab_size_bytes();
1136 } else {
1137 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1138 }
1139 }
1140
1141 size_t ShenandoahHeap::max_tlab_size() const {
1142 // Returns size in words
1143 return ShenandoahHeapRegion::max_tlab_size_words();
1144 }
1145
1146 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1147 public:
1148 void do_thread(Thread* thread) {
1149 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1150 gclab->retire();
1151 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1152 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1153 }
1154 }
1155 };
1156
1157 void ShenandoahHeap::retire_and_reset_gclabs() {
1158 ShenandoahRetireAndResetGCLABClosure cl;
1159 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1160 cl.do_thread(t);
1161 }
1162 workers()->threads_do(&cl);
1163 }
1164
1165 void ShenandoahHeap::collect(GCCause::Cause cause) {
1166 control_thread()->request_gc(cause);
1167 }
1168
1169 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1170 //assert(false, "Shouldn't need to do full collections");
1171 }
1172
1173 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1174 return _shenandoah_policy;
1175 }
1176
1177 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1178 Space* sp = heap_region_containing(addr);
1179 if (sp != NULL) {
1180 return sp->block_start(addr);
1181 }
1182 return NULL;
1183 }
1184
1185 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1186 Space* sp = heap_region_containing(addr);
1187 return sp->block_is_obj(addr);
1188 }
1189
1190 jlong ShenandoahHeap::millis_since_last_gc() {
1191 double v = heuristics()->time_since_last_gc() * 1000;
1192 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1193 return (jlong)v;
1194 }
1195
1196 void ShenandoahHeap::prepare_for_verify() {
1197 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1198 make_parsable(false);
1199 }
1200 }
1201
1202 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1203 workers()->print_worker_threads_on(st);
1204 if (ShenandoahStringDedup::is_enabled()) {
1205 ShenandoahStringDedup::print_worker_threads_on(st);
1206 }
1207 }
1208
1209 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1210 workers()->threads_do(tcl);
1211 _safepoint_workers->threads_do(tcl);
1212 if (ShenandoahStringDedup::is_enabled()) {
1213 ShenandoahStringDedup::threads_do(tcl);
1214 }
1215 }
1216
1217 void ShenandoahHeap::print_tracing_info() const {
1218 LogTarget(Info, gc, stats) lt;
1219 if (lt.is_enabled()) {
1220 ResourceMark rm;
1221 LogStream ls(lt);
1222
1223 phase_timings()->print_on(&ls);
1224
1225 ls.cr();
1226 ls.cr();
1227
1228 shenandoah_policy()->print_gc_stats(&ls);
1229
1230 ls.cr();
1231 ls.cr();
1232
1233 if (ShenandoahPacing) {
1234 pacer()->print_on(&ls);
1235 }
1236
1237 ls.cr();
1238 ls.cr();
1239
1240 if (ShenandoahAllocationTrace) {
1241 assert(alloc_tracker() != NULL, "Must be");
1242 alloc_tracker()->print_on(&ls);
1243 } else {
1244 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1245 }
1246 }
1247 }
1248
1249 void ShenandoahHeap::verify(VerifyOption vo) {
1250 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1251 if (ShenandoahVerify) {
1252 verifier()->verify_generic(vo);
1253 } else {
1254 // TODO: Consider allocating verification bitmaps on demand,
1255 // and turn this on unconditionally.
1256 }
1257 }
1258 }
1259 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1260 return _free_set->capacity();
1261 }
1262
1263 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1264 private:
1265 MarkBitMap* _bitmap;
1266 Stack<oop,mtGC>* _oop_stack;
1267
1268 template <class T>
1269 void do_oop_work(T* p) {
1270 T o = RawAccess<>::oop_load(p);
1271 if (!CompressedOops::is_null(o)) {
1272 oop obj = CompressedOops::decode_not_null(o);
1273 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1274 assert(oopDesc::is_oop(obj), "must be a valid oop");
1275 if (!_bitmap->is_marked((HeapWord*) obj)) {
1276 _bitmap->mark((HeapWord*) obj);
1277 _oop_stack->push(obj);
1278 }
1279 }
1280 }
1281 public:
1282 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1283 _bitmap(bitmap), _oop_stack(oop_stack) {}
1284 void do_oop(oop* p) { do_oop_work(p); }
1285 void do_oop(narrowOop* p) { do_oop_work(p); }
1286 };
1287
1288 /*
1289 * This is public API, used in preparation of object_iterate().
1290 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1291 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1292 * control, we call SH::make_tlabs_parsable().
1293 */
1294 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1295 // No-op.
1296 }
1297
1298 /*
1299 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1300 *
1301 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1302 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1303 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1304 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1305 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1306 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1307 * wiped the bitmap in preparation for next marking).
1308 *
1309 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1310 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1311 * is allowed to report dead objects, but is not required to do so.
1312 */
1313 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1314 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1315 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1316 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1317 return;
1318 }
1319
1320 // Reset bitmap
1321 _aux_bit_map.clear();
1322
1323 Stack<oop,mtGC> oop_stack;
1324
1325 // First, we process all GC roots. This populates the work stack with initial objects.
1326 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1327 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1328 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1329 CodeBlobToOopClosure blobs(&oops, false);
1330 rp.process_all_roots(&oops, &clds, &blobs, NULL, 0);
1331
1332 // Work through the oop stack to traverse heap.
1333 while (! oop_stack.is_empty()) {
1334 oop obj = oop_stack.pop();
1335 assert(oopDesc::is_oop(obj), "must be a valid oop");
1336 cl->do_object(obj);
1337 obj->oop_iterate(&oops);
1338 }
1339
1340 assert(oop_stack.is_empty(), "should be empty");
1341
1342 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1343 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1344 }
1345 }
1346
1347 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1348 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1349 object_iterate(cl);
1350 }
1351
1352 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1353 for (size_t i = 0; i < num_regions(); i++) {
1354 ShenandoahHeapRegion* current = get_region(i);
1355 blk->heap_region_do(current);
1356 }
1357 }
1358
1359 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1360 private:
1361 ShenandoahHeap* const _heap;
1362 ShenandoahHeapRegionClosure* const _blk;
1363
1364 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1365 volatile size_t _index;
1366 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1367
1368 public:
1369 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1370 AbstractGangTask("Parallel Region Task"),
1371 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1372
1373 void work(uint worker_id) {
1374 size_t stride = ShenandoahParallelRegionStride;
1375
1376 size_t max = _heap->num_regions();
1377 while (_index < max) {
1378 size_t cur = Atomic::add(stride, &_index) - stride;
1379 size_t start = cur;
1380 size_t end = MIN2(cur + stride, max);
1381 if (start >= max) break;
1382
1383 for (size_t i = cur; i < end; i++) {
1384 ShenandoahHeapRegion* current = _heap->get_region(i);
1385 _blk->heap_region_do(current);
1386 }
1387 }
1388 }
1389 };
1390
1391 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1392 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1393 if (num_regions() > ShenandoahParallelRegionStride) {
1394 ShenandoahParallelHeapRegionTask task(blk);
1395 workers()->run_task(&task);
1396 } else {
1397 heap_region_iterate(blk);
1398 }
1399 }
1400
1401 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1402 private:
1403 ShenandoahMarkingContext* const _ctx;
1404 public:
1405 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1406
1407 void heap_region_do(ShenandoahHeapRegion* r) {
1408 if (r->is_active()) {
1409 r->clear_live_data();
1410 _ctx->capture_top_at_mark_start(r);
1411 } else {
1412 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1413 assert(_ctx->top_at_mark_start(r) == r->top(),
1414 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1415 }
1416 }
1417
1418 bool is_thread_safe() { return true; }
1419 };
1420
1421 void ShenandoahHeap::op_init_mark() {
1422 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1423 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1424
1425 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1426 assert(!marking_context()->is_complete(), "should not be complete");
1427
1428 if (ShenandoahVerify) {
1429 verifier()->verify_before_concmark();
1430 }
1431
1432 if (VerifyBeforeGC) {
1433 Universe::verify();
1434 }
1435
1436 set_concurrent_mark_in_progress(true);
1437 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1438 {
1439 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1440 make_parsable(true);
1441 }
1442
1443 {
1444 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1445 ShenandoahClearLivenessClosure clc;
1446 parallel_heap_region_iterate(&clc);
1447 }
1448
1449 // Make above changes visible to worker threads
1450 OrderAccess::fence();
1451
1452 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1453
1454 if (UseTLAB) {
1455 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1456 resize_tlabs();
1457 }
1458
1459 if (ShenandoahPacing) {
1460 pacer()->setup_for_mark();
1461 }
1462 }
1463
1464 void ShenandoahHeap::op_mark() {
1465 concurrent_mark()->mark_from_roots();
1466 }
1467
1468 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1469 private:
1470 ShenandoahMarkingContext* const _ctx;
1471 public:
1472 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1473
1474 void heap_region_do(ShenandoahHeapRegion* r) {
1475 if (r->is_active()) {
1476 HeapWord *tams = _ctx->top_at_mark_start(r);
1477 HeapWord *top = r->top();
1478 if (top > tams) {
1479 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1480 }
1481 } else {
1482 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1483 assert(_ctx->top_at_mark_start(r) == r->top(),
1484 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1485 }
1486 }
1487
1488 bool is_thread_safe() { return true; }
1489 };
1490
1491 void ShenandoahHeap::op_final_mark() {
1492 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1493
1494 // It is critical that we
1495 // evacuate roots right after finishing marking, so that we don't
1496 // get unmarked objects in the roots.
1497
1498 if (!cancelled_gc()) {
1499 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1500
1501 if (has_forwarded_objects()) {
1502 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots);
1503 }
1504
1505 stop_concurrent_marking();
1506
1507 {
1508 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1509
1510 // All allocations past TAMS are implicitly live, adjust the region data.
1511 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1512 ShenandoahCompleteLivenessClosure cl;
1513 parallel_heap_region_iterate(&cl);
1514 }
1515
1516 {
1517 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1518
1519 make_parsable(true);
1520
1521 trash_cset_regions();
1522
1523 {
1524 ShenandoahHeapLocker locker(lock());
1525 _collection_set->clear();
1526 _free_set->clear();
1527
1528 heuristics()->choose_collection_set(_collection_set);
1529
1530 _free_set->rebuild();
1531 }
1532 }
1533
1534 // If collection set has candidates, start evacuation.
1535 // Otherwise, bypass the rest of the cycle.
1536 if (!collection_set()->is_empty()) {
1537 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1538
1539 if (ShenandoahVerify) {
1540 verifier()->verify_before_evacuation();
1541 }
1542
1543 set_evacuation_in_progress(true);
1544 // From here on, we need to update references.
1545 set_has_forwarded_objects(true);
1546
1547 evacuate_and_update_roots();
1548
1549 if (ShenandoahPacing) {
1550 pacer()->setup_for_evac();
1551 }
1552 } else {
1553 if (ShenandoahVerify) {
1554 verifier()->verify_after_concmark();
1555 }
1556
1557 if (VerifyAfterGC) {
1558 Universe::verify();
1559 }
1560 }
1561
1562 } else {
1563 concurrent_mark()->cancel();
1564 stop_concurrent_marking();
1565
1566 if (process_references()) {
1567 // Abandon reference processing right away: pre-cleaning must have failed.
1568 ReferenceProcessor *rp = ref_processor();
1569 rp->disable_discovery();
1570 rp->abandon_partial_discovery();
1571 rp->verify_no_references_recorded();
1572 }
1573 }
1574 }
1575
1576 void ShenandoahHeap::op_final_evac() {
1577 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1578
1579 set_evacuation_in_progress(false);
1580
1581 retire_and_reset_gclabs();
1582
1583 if (ShenandoahVerify) {
1584 verifier()->verify_after_evacuation();
1585 }
1586
1587 if (VerifyAfterGC) {
1588 Universe::verify();
1589 }
1590 }
1591
1592 void ShenandoahHeap::op_conc_evac() {
1593 ShenandoahEvacuationTask task(this, _collection_set, true);
1594 workers()->run_task(&task);
1595 }
1596
1597 void ShenandoahHeap::op_stw_evac() {
1598 ShenandoahEvacuationTask task(this, _collection_set, false);
1599 workers()->run_task(&task);
1600 }
1601
1602 void ShenandoahHeap::op_updaterefs() {
1603 update_heap_references(true);
1604 }
1605
1606 void ShenandoahHeap::op_cleanup() {
1607 free_set()->recycle_trash();
1608 }
1609
1610 void ShenandoahHeap::op_reset() {
1611 reset_mark_bitmap();
1612 }
1613
1614 void ShenandoahHeap::op_preclean() {
1615 concurrent_mark()->preclean_weak_refs();
1616 }
1617
1618 void ShenandoahHeap::op_init_traversal() {
1619 traversal_gc()->init_traversal_collection();
1620 }
1621
1622 void ShenandoahHeap::op_traversal() {
1623 traversal_gc()->concurrent_traversal_collection();
1624 }
1625
1626 void ShenandoahHeap::op_final_traversal() {
1627 traversal_gc()->final_traversal_collection();
1628 }
1629
1630 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1631 ShenandoahMetricsSnapshot metrics;
1632 metrics.snap_before();
1633
1634 full_gc()->do_it(cause);
1635 if (UseTLAB) {
1636 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1637 resize_all_tlabs();
1638 }
1639
1640 metrics.snap_after();
1641 metrics.print();
1642
1643 if (metrics.is_good_progress("Full GC")) {
1644 _progress_last_gc.set();
1645 } else {
1646 // Nothing to do. Tell the allocation path that we have failed to make
1647 // progress, and it can finally fail.
1648 _progress_last_gc.unset();
1649 }
1650 }
1651
1652 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1653 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1654 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1655 // some phase, we have to upgrade the Degenerate GC to Full GC.
1656
1657 clear_cancelled_gc();
1658
1659 ShenandoahMetricsSnapshot metrics;
1660 metrics.snap_before();
1661
1662 switch (point) {
1663 case _degenerated_traversal:
1664 {
1665 // Drop the collection set. Note: this leaves some already forwarded objects
1666 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1667 // workarounds in ShenandoahTraversalHeuristics.
1668
1669 ShenandoahHeapLocker locker(lock());
1670 collection_set()->clear_current_index();
1671 for (size_t i = 0; i < collection_set()->count(); i++) {
1672 ShenandoahHeapRegion* r = collection_set()->next();
1673 r->make_regular_bypass();
1674 }
1675 collection_set()->clear();
1676 }
1677 op_final_traversal();
1678 op_cleanup();
1679 return;
1680
1681 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1682 // but enters it at different points, depending on which concurrent phase had
1683 // degenerated.
1684
1685 case _degenerated_outside_cycle:
1686 // We have degenerated from outside the cycle, which means something is bad with
1687 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1688 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1689 // we can do the most aggressive degen cycle, which includes processing references and
1690 // class unloading, unless those features are explicitly disabled.
1691 //
1692 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1693 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1694 set_process_references(heuristics()->can_process_references());
1695 set_unload_classes(heuristics()->can_unload_classes());
1696
1697 if (heuristics()->can_do_traversal_gc()) {
1698 // Not possible to degenerate from here, upgrade to Full GC right away.
1699 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1700 op_degenerated_fail();
1701 return;
1702 }
1703
1704 op_reset();
1705
1706 op_init_mark();
1707 if (cancelled_gc()) {
1708 op_degenerated_fail();
1709 return;
1710 }
1711
1712 case _degenerated_mark:
1713 op_final_mark();
1714 if (cancelled_gc()) {
1715 op_degenerated_fail();
1716 return;
1717 }
1718
1719 op_cleanup();
1720
1721 case _degenerated_evac:
1722 // If heuristics thinks we should do the cycle, this flag would be set,
1723 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1724 if (is_evacuation_in_progress()) {
1725
1726 // Degeneration under oom-evac protocol might have left some objects in
1727 // collection set un-evacuated. Restart evacuation from the beginning to
1728 // capture all objects. For all the objects that are already evacuated,
1729 // it would be a simple check, which is supposed to be fast. This is also
1730 // safe to do even without degeneration, as CSet iterator is at beginning
1731 // in preparation for evacuation anyway.
1732 collection_set()->clear_current_index();
1733
1734 op_stw_evac();
1735 if (cancelled_gc()) {
1736 op_degenerated_fail();
1737 return;
1738 }
1739 }
1740
1741 // If heuristics thinks we should do the cycle, this flag would be set,
1742 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1743 if (has_forwarded_objects()) {
1744 op_init_updaterefs();
1745 if (cancelled_gc()) {
1746 op_degenerated_fail();
1747 return;
1748 }
1749 }
1750
1751 case _degenerated_updaterefs:
1752 if (has_forwarded_objects()) {
1753 op_final_updaterefs();
1754 if (cancelled_gc()) {
1755 op_degenerated_fail();
1756 return;
1757 }
1758 }
1759
1760 op_cleanup();
1761 break;
1762
1763 default:
1764 ShouldNotReachHere();
1765 }
1766
1767 if (ShenandoahVerify) {
1768 verifier()->verify_after_degenerated();
1769 }
1770
1771 if (VerifyAfterGC) {
1772 Universe::verify();
1773 }
1774
1775 metrics.snap_after();
1776 metrics.print();
1777
1778 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1779 // because that probably means the heap is overloaded and/or fragmented.
1780 if (!metrics.is_good_progress("Degenerated GC")) {
1781 _progress_last_gc.unset();
1782 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1783 op_degenerated_futile();
1784 } else {
1785 _progress_last_gc.set();
1786 }
1787 }
1788
1789 void ShenandoahHeap::op_degenerated_fail() {
1790 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1791 shenandoah_policy()->record_degenerated_upgrade_to_full();
1792 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1793 }
1794
1795 void ShenandoahHeap::op_degenerated_futile() {
1796 shenandoah_policy()->record_degenerated_upgrade_to_full();
1797 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1798 }
1799
1800 void ShenandoahHeap::stop_concurrent_marking() {
1801 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1802 if (!cancelled_gc()) {
1803 // If we needed to update refs, and concurrent marking has been cancelled,
1804 // we need to finish updating references.
1805 set_has_forwarded_objects(false);
1806 mark_complete_marking_context();
1807 }
1808 set_concurrent_mark_in_progress(false);
1809 }
1810
1811 void ShenandoahHeap::force_satb_flush_all_threads() {
1812 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1813 // No need to flush SATBs
1814 return;
1815 }
1816
1817 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1818 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1819 }
1820 // The threads are not "acquiring" their thread-local data, but it does not
1821 // hurt to "release" the updates here anyway.
1822 OrderAccess::fence();
1823 }
1824
1825 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1826 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1827 ShenandoahThreadLocalData::set_gc_state(t, state);
1828 }
1829 }
1830
1831 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1832 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1833 _gc_state.set_cond(mask, value);
1834 set_gc_state_all_threads(_gc_state.raw_value());
1835 }
1836
1837 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1838 set_gc_state_mask(MARKING, in_progress);
1839 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1840 }
1841
1842 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1843 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1844 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1845 }
1846
1847 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1848 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1849 set_gc_state_mask(EVACUATION, in_progress);
1850 }
1851
1852 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1853 // Initialize Brooks pointer for the next object
1854 HeapWord* result = obj + ShenandoahBrooksPointer::word_size();
1855 ShenandoahBrooksPointer::initialize(oop(result));
1856 return result;
1857 }
1858
1859 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1860 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1861 }
1862
1863 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1864 _mark_context(ShenandoahHeap::heap()->marking_context()) {
1865 }
1866
1867 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1868 if (CompressedOops::is_null(obj)) {
1869 return false;
1870 }
1871 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1872 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1873 return _mark_context->is_marked(obj);
1874 }
1875
1876 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1877 if (CompressedOops::is_null(obj)) {
1878 return false;
1879 }
1880 shenandoah_assert_not_forwarded(NULL, obj);
1881 return _mark_context->is_marked(obj);
1882 }
1883
1884 void ShenandoahHeap::ref_processing_init() {
1885 assert(_max_workers > 0, "Sanity");
1886
1887 _ref_processor =
1888 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1889 ParallelRefProcEnabled, // MT processing
1890 _max_workers, // Degree of MT processing
1891 true, // MT discovery
1892 _max_workers, // Degree of MT discovery
1893 false, // Reference discovery is not atomic
1894 NULL, // No closure, should be installed before use
1895 true); // Scale worker threads
1896
1897 shenandoah_assert_rp_isalive_not_installed();
1898 }
1899
1900 GCTracer* ShenandoahHeap::tracer() {
1901 return shenandoah_policy()->tracer();
1902 }
1903
1904 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1905 return _free_set->used();
1906 }
1907
1908 bool ShenandoahHeap::try_cancel_gc() {
1909 while (true) {
1910 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1911 if (prev == CANCELLABLE) return true;
1912 else if (prev == CANCELLED) return false;
1913 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1914 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1915 {
1916 // We need to provide a safepoint here, otherwise we might
1917 // spin forever if a SP is pending.
1918 ThreadBlockInVM sp(JavaThread::current());
1919 SpinPause();
1920 }
1921 }
1922 }
1923
1924 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1925 if (try_cancel_gc()) {
1926 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1927 log_info(gc)("%s", msg.buffer());
1928 Events::log(Thread::current(), "%s", msg.buffer());
1929 }
1930 }
1931
1932 uint ShenandoahHeap::max_workers() {
1933 return _max_workers;
1934 }
1935
1936 void ShenandoahHeap::stop() {
1937 // The shutdown sequence should be able to terminate when GC is running.
1938
1939 // Step 0. Notify policy to disable event recording.
1940 _shenandoah_policy->record_shutdown();
1941
1942 // Step 1. Notify control thread that we are in shutdown.
1943 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1944 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1945 control_thread()->prepare_for_graceful_shutdown();
1946
1947 // Step 2. Notify GC workers that we are cancelling GC.
1948 cancel_gc(GCCause::_shenandoah_stop_vm);
1949
1950 // Step 3. Wait until GC worker exits normally.
1951 control_thread()->stop();
1952
1953 // Step 4. Stop String Dedup thread if it is active
1954 if (ShenandoahStringDedup::is_enabled()) {
1955 ShenandoahStringDedup::stop();
1956 }
1957 }
1958
1959 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1960 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1961
1962 ShenandoahGCPhase root_phase(full_gc ?
1963 ShenandoahPhaseTimings::full_gc_purge :
1964 ShenandoahPhaseTimings::purge);
1965
1966 ShenandoahIsAliveSelector alive;
1967 BoolObjectClosure* is_alive = alive.is_alive_closure();
1968
1969 bool purged_class;
1970
1971 // Unload classes and purge SystemDictionary.
1972 {
1973 ShenandoahGCPhase phase(full_gc ?
1974 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1975 ShenandoahPhaseTimings::purge_class_unload);
1976 purged_class = SystemDictionary::do_unloading(gc_timer());
1977 }
1978
1979 {
1980 ShenandoahGCPhase phase(full_gc ?
1981 ShenandoahPhaseTimings::full_gc_purge_par :
1982 ShenandoahPhaseTimings::purge_par);
1983 uint active = _workers->active_workers();
1984 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1985 _workers->run_task(&unlink_task);
1986 }
1987
1988 {
1989 ShenandoahGCPhase phase(full_gc ?
1990 ShenandoahPhaseTimings::full_gc_purge_cldg :
1991 ShenandoahPhaseTimings::purge_cldg);
1992 ClassLoaderDataGraph::purge();
1993 }
1994 }
1995
1996 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1997 set_gc_state_mask(HAS_FORWARDED, cond);
1998 }
1999
2000 void ShenandoahHeap::set_process_references(bool pr) {
2001 _process_references.set_cond(pr);
2002 }
2003
2004 void ShenandoahHeap::set_unload_classes(bool uc) {
2005 _unload_classes.set_cond(uc);
2006 }
2007
2008 bool ShenandoahHeap::process_references() const {
2009 return _process_references.is_set();
2010 }
2011
2012 bool ShenandoahHeap::unload_classes() const {
2013 return _unload_classes.is_set();
2014 }
2015
2016 address ShenandoahHeap::in_cset_fast_test_addr() {
2017 ShenandoahHeap* heap = ShenandoahHeap::heap();
2018 assert(heap->collection_set() != NULL, "Sanity");
2019 return (address) heap->collection_set()->biased_map_address();
2020 }
2021
2022 address ShenandoahHeap::cancelled_gc_addr() {
2023 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2024 }
2025
2026 address ShenandoahHeap::gc_state_addr() {
2027 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2028 }
2029
2030 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2031 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2032 }
2033
2034 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2035 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2036 }
2037
2038 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2039 _degenerated_gc_in_progress.set_cond(in_progress);
2040 }
2041
2042 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2043 _full_gc_in_progress.set_cond(in_progress);
2044 }
2045
2046 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2047 assert (is_full_gc_in_progress(), "should be");
2048 _full_gc_move_in_progress.set_cond(in_progress);
2049 }
2050
2051 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2052 set_gc_state_mask(UPDATEREFS, in_progress);
2053 }
2054
2055 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2056 ShenandoahCodeRoots::add_nmethod(nm);
2057 }
2058
2059 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2060 ShenandoahCodeRoots::remove_nmethod(nm);
2061 }
2062
2063 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2064 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2065 ShenandoahHeapLocker locker(lock());
2066 heap_region_containing(o)->make_pinned();
2067 return o;
2068 }
2069
2070 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2071 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2072 ShenandoahHeapLocker locker(lock());
2073 heap_region_containing(o)->make_unpinned();
2074 }
2075
2076 GCTimer* ShenandoahHeap::gc_timer() const {
2077 return _gc_timer;
2078 }
2079
2080 #ifdef ASSERT
2081 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2082 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2083
2084 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2085 if (UseDynamicNumberOfGCThreads ||
2086 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2087 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2088 } else {
2089 // Use ParallelGCThreads inside safepoints
2090 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2091 }
2092 } else {
2093 if (UseDynamicNumberOfGCThreads ||
2094 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2095 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2096 } else {
2097 // Use ConcGCThreads outside safepoints
2098 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2099 }
2100 }
2101 }
2102 #endif
2103
2104 ShenandoahVerifier* ShenandoahHeap::verifier() {
2105 guarantee(ShenandoahVerify, "Should be enabled");
2106 assert (_verifier != NULL, "sanity");
2107 return _verifier;
2108 }
2109
2110 template<class T>
2111 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2112 private:
2113 T cl;
2114 ShenandoahHeap* _heap;
2115 ShenandoahRegionIterator* _regions;
2116 bool _concurrent;
2117 public:
2118 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2119 AbstractGangTask("Concurrent Update References Task"),
2120 cl(T()),
2121 _heap(ShenandoahHeap::heap()),
2122 _regions(regions),
2123 _concurrent(concurrent) {
2124 }
2125
2126 void work(uint worker_id) {
2127 if (_concurrent) {
2128 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2129 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2130 do_work();
2131 } else {
2132 ShenandoahParallelWorkerSession worker_session(worker_id);
2133 do_work();
2134 }
2135 }
2136
2137 private:
2138 void do_work() {
2139 ShenandoahHeapRegion* r = _regions->next();
2140 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2141 while (r != NULL) {
2142 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2143 assert (top_at_start_ur >= r->bottom(), "sanity");
2144 if (r->is_active() && !r->is_cset()) {
2145 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2146 }
2147 if (ShenandoahPacing) {
2148 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2149 }
2150 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2151 return;
2152 }
2153 r = _regions->next();
2154 }
2155 }
2156 };
2157
2158 void ShenandoahHeap::update_heap_references(bool concurrent) {
2159 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2160 workers()->run_task(&task);
2161 }
2162
2163 void ShenandoahHeap::op_init_updaterefs() {
2164 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2165
2166 set_evacuation_in_progress(false);
2167
2168 retire_and_reset_gclabs();
2169
2170 if (ShenandoahVerify) {
2171 verifier()->verify_before_updaterefs();
2172 }
2173
2174 set_update_refs_in_progress(true);
2175 make_parsable(true);
2176 for (uint i = 0; i < num_regions(); i++) {
2177 ShenandoahHeapRegion* r = get_region(i);
2178 r->set_concurrent_iteration_safe_limit(r->top());
2179 }
2180
2181 // Reset iterator.
2182 _update_refs_iterator.reset();
2183
2184 if (ShenandoahPacing) {
2185 pacer()->setup_for_updaterefs();
2186 }
2187 }
2188
2189 void ShenandoahHeap::op_final_updaterefs() {
2190 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2191
2192 // Check if there is left-over work, and finish it
2193 if (_update_refs_iterator.has_next()) {
2194 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2195
2196 // Finish updating references where we left off.
2197 clear_cancelled_gc();
2198 update_heap_references(false);
2199 }
2200
2201 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2202 // everything. On degenerated paths, cancelled gc would not be set anyway.
2203 if (cancelled_gc()) {
2204 clear_cancelled_gc();
2205 }
2206 assert(!cancelled_gc(), "Should have been done right before");
2207
2208 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2209 ShenandoahPhaseTimings::degen_gc_update_roots:
2210 ShenandoahPhaseTimings::final_update_refs_roots);
2211
2212 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2213
2214 trash_cset_regions();
2215 set_has_forwarded_objects(false);
2216 set_update_refs_in_progress(false);
2217
2218 if (ShenandoahVerify) {
2219 verifier()->verify_after_updaterefs();
2220 }
2221
2222 if (VerifyAfterGC) {
2223 Universe::verify();
2224 }
2225
2226 {
2227 ShenandoahHeapLocker locker(lock());
2228 _free_set->rebuild();
2229 }
2230 }
2231
2232 #ifdef ASSERT
2233 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2234 _lock.assert_owned_by_current_thread();
2235 }
2236
2237 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2238 _lock.assert_not_owned_by_current_thread();
2239 }
2240
2241 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2242 _lock.assert_owned_by_current_thread_or_safepoint();
2243 }
2244 #endif
2245
2246 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2247 print_on(st);
2248 print_heap_regions_on(st);
2249 }
2250
2251 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2252 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2253
2254 size_t regions_from = _bitmap_regions_per_slice * slice;
2255 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2256 for (size_t g = regions_from; g < regions_to; g++) {
2257 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2258 if (skip_self && g == r->region_number()) continue;
2259 if (get_region(g)->is_committed()) {
2260 return true;
2261 }
2262 }
2263 return false;
2264 }
2265
2266 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2267 assert_heaplock_owned_by_current_thread();
2268
2269 // Bitmaps in special regions do not need commits
2270 if (_bitmap_region_special) {
2271 return true;
2272 }
2273
2274 if (is_bitmap_slice_committed(r, true)) {
2275 // Some other region from the group is already committed, meaning the bitmap
2276 // slice is already committed, we exit right away.
2277 return true;
2278 }
2279
2280 // Commit the bitmap slice:
2281 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2282 size_t off = _bitmap_bytes_per_slice * slice;
2283 size_t len = _bitmap_bytes_per_slice;
2284 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2285 return false;
2286 }
2287 return true;
2288 }
2289
2290 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2291 assert_heaplock_owned_by_current_thread();
2292
2293 // Bitmaps in special regions do not need uncommits
2294 if (_bitmap_region_special) {
2295 return true;
2296 }
2297
2298 if (is_bitmap_slice_committed(r, true)) {
2299 // Some other region from the group is still committed, meaning the bitmap
2300 // slice is should stay committed, exit right away.
2301 return true;
2302 }
2303
2304 // Uncommit the bitmap slice:
2305 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2306 size_t off = _bitmap_bytes_per_slice * slice;
2307 size_t len = _bitmap_bytes_per_slice;
2308 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2309 return false;
2310 }
2311 return true;
2312 }
2313
2314 void ShenandoahHeap::safepoint_synchronize_begin() {
2315 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2316 SuspendibleThreadSet::synchronize();
2317 }
2318 }
2319
2320 void ShenandoahHeap::safepoint_synchronize_end() {
2321 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2322 SuspendibleThreadSet::desynchronize();
2323 }
2324 }
2325
2326 void ShenandoahHeap::vmop_entry_init_mark() {
2327 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2328 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2329 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2330
2331 try_inject_alloc_failure();
2332 VM_ShenandoahInitMark op;
2333 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2334 }
2335
2336 void ShenandoahHeap::vmop_entry_final_mark() {
2337 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2338 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2339 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2340
2341 try_inject_alloc_failure();
2342 VM_ShenandoahFinalMarkStartEvac op;
2343 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2344 }
2345
2346 void ShenandoahHeap::vmop_entry_final_evac() {
2347 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2348 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2349 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2350
2351 VM_ShenandoahFinalEvac op;
2352 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2353 }
2354
2355 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2356 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2357 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2358 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2359
2360 try_inject_alloc_failure();
2361 VM_ShenandoahInitUpdateRefs op;
2362 VMThread::execute(&op);
2363 }
2364
2365 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2366 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2367 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2368 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2369
2370 try_inject_alloc_failure();
2371 VM_ShenandoahFinalUpdateRefs op;
2372 VMThread::execute(&op);
2373 }
2374
2375 void ShenandoahHeap::vmop_entry_init_traversal() {
2376 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2377 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2378 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2379
2380 try_inject_alloc_failure();
2381 VM_ShenandoahInitTraversalGC op;
2382 VMThread::execute(&op);
2383 }
2384
2385 void ShenandoahHeap::vmop_entry_final_traversal() {
2386 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2387 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2389
2390 try_inject_alloc_failure();
2391 VM_ShenandoahFinalTraversalGC op;
2392 VMThread::execute(&op);
2393 }
2394
2395 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2396 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2397 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2398 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2399
2400 try_inject_alloc_failure();
2401 VM_ShenandoahFullGC op(cause);
2402 VMThread::execute(&op);
2403 }
2404
2405 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2406 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2407 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2408 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2409
2410 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2411 VMThread::execute(°enerated_gc);
2412 }
2413
2414 void ShenandoahHeap::entry_init_mark() {
2415 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2416 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2417 const char* msg = init_mark_event_message();
2418 GCTraceTime(Info, gc) time(msg, gc_timer());
2419 EventMark em("%s", msg);
2420
2421 ShenandoahWorkerScope scope(workers(),
2422 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2423 "init marking");
2424
2425 op_init_mark();
2426 }
2427
2428 void ShenandoahHeap::entry_final_mark() {
2429 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2430 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2431 const char* msg = final_mark_event_message();
2432 GCTraceTime(Info, gc) time(msg, gc_timer());
2433 EventMark em("%s", msg);
2434
2435 ShenandoahWorkerScope scope(workers(),
2436 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2437 "final marking");
2438
2439 op_final_mark();
2440 }
2441
2442 void ShenandoahHeap::entry_final_evac() {
2443 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2444 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2445 static const char* msg = "Pause Final Evac";
2446 GCTraceTime(Info, gc) time(msg, gc_timer());
2447 EventMark em("%s", msg);
2448
2449 op_final_evac();
2450 }
2451
2452 void ShenandoahHeap::entry_init_updaterefs() {
2453 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2454 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2455
2456 static const char* msg = "Pause Init Update Refs";
2457 GCTraceTime(Info, gc) time(msg, gc_timer());
2458 EventMark em("%s", msg);
2459
2460 // No workers used in this phase, no setup required
2461
2462 op_init_updaterefs();
2463 }
2464
2465 void ShenandoahHeap::entry_final_updaterefs() {
2466 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2467 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2468
2469 static const char* msg = "Pause Final Update Refs";
2470 GCTraceTime(Info, gc) time(msg, gc_timer());
2471 EventMark em("%s", msg);
2472
2473 ShenandoahWorkerScope scope(workers(),
2474 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2475 "final reference update");
2476
2477 op_final_updaterefs();
2478 }
2479
2480 void ShenandoahHeap::entry_init_traversal() {
2481 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2482 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2483
2484 static const char* msg = "Pause Init Traversal";
2485 GCTraceTime(Info, gc) time(msg, gc_timer());
2486 EventMark em("%s", msg);
2487
2488 ShenandoahWorkerScope scope(workers(),
2489 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2490 "init traversal");
2491
2492 op_init_traversal();
2493 }
2494
2495 void ShenandoahHeap::entry_final_traversal() {
2496 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2497 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2498
2499 static const char* msg = "Pause Final Traversal";
2500 GCTraceTime(Info, gc) time(msg, gc_timer());
2501 EventMark em("%s", msg);
2502
2503 ShenandoahWorkerScope scope(workers(),
2504 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2505 "final traversal");
2506
2507 op_final_traversal();
2508 }
2509
2510 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2511 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2512 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2513
2514 static const char* msg = "Pause Full";
2515 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2516 EventMark em("%s", msg);
2517
2518 ShenandoahWorkerScope scope(workers(),
2519 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2520 "full gc");
2521
2522 op_full(cause);
2523 }
2524
2525 void ShenandoahHeap::entry_degenerated(int point) {
2526 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2527 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2528
2529 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2530 const char* msg = degen_event_message(dpoint);
2531 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2532 EventMark em("%s", msg);
2533
2534 ShenandoahWorkerScope scope(workers(),
2535 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2536 "stw degenerated gc");
2537
2538 set_degenerated_gc_in_progress(true);
2539 op_degenerated(dpoint);
2540 set_degenerated_gc_in_progress(false);
2541 }
2542
2543 void ShenandoahHeap::entry_mark() {
2544 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2545
2546 const char* msg = conc_mark_event_message();
2547 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2548 EventMark em("%s", msg);
2549
2550 ShenandoahWorkerScope scope(workers(),
2551 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2552 "concurrent marking");
2553
2554 try_inject_alloc_failure();
2555 op_mark();
2556 }
2557
2558 void ShenandoahHeap::entry_evac() {
2559 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2560 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2561
2562 static const char* msg = "Concurrent evacuation";
2563 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2564 EventMark em("%s", msg);
2565
2566 ShenandoahWorkerScope scope(workers(),
2567 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2568 "concurrent evacuation");
2569
2570 try_inject_alloc_failure();
2571 op_conc_evac();
2572 }
2573
2574 void ShenandoahHeap::entry_updaterefs() {
2575 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2576
2577 static const char* msg = "Concurrent update references";
2578 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2579 EventMark em("%s", msg);
2580
2581 ShenandoahWorkerScope scope(workers(),
2582 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2583 "concurrent reference update");
2584
2585 try_inject_alloc_failure();
2586 op_updaterefs();
2587 }
2588 void ShenandoahHeap::entry_cleanup() {
2589 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2590
2591 static const char* msg = "Concurrent cleanup";
2592 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2593 EventMark em("%s", msg);
2594
2595 // This phase does not use workers, no need for setup
2596
2597 try_inject_alloc_failure();
2598 op_cleanup();
2599 }
2600
2601 void ShenandoahHeap::entry_reset() {
2602 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2603
2604 static const char* msg = "Concurrent reset";
2605 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2606 EventMark em("%s", msg);
2607
2608 ShenandoahWorkerScope scope(workers(),
2609 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2610 "concurrent reset");
2611
2612 try_inject_alloc_failure();
2613 op_reset();
2614 }
2615
2616 void ShenandoahHeap::entry_preclean() {
2617 if (ShenandoahPreclean && process_references()) {
2618 static const char* msg = "Concurrent precleaning";
2619 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2620 EventMark em("%s", msg);
2621
2622 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2623
2624 ShenandoahWorkerScope scope(workers(),
2625 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2626 "concurrent preclean",
2627 /* check_workers = */ false);
2628
2629 try_inject_alloc_failure();
2630 op_preclean();
2631 }
2632 }
2633
2634 void ShenandoahHeap::entry_traversal() {
2635 static const char* msg = "Concurrent traversal";
2636 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2637 EventMark em("%s", msg);
2638
2639 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2640
2641 ShenandoahWorkerScope scope(workers(),
2642 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2643 "concurrent traversal");
2644
2645 try_inject_alloc_failure();
2646 op_traversal();
2647 }
2648
2649 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2650 static const char *msg = "Concurrent uncommit";
2651 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2652 EventMark em("%s", msg);
2653
2654 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2655
2656 op_uncommit(shrink_before);
2657 }
2658
2659 void ShenandoahHeap::try_inject_alloc_failure() {
2660 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2661 _inject_alloc_failure.set();
2662 os::naked_short_sleep(1);
2663 if (cancelled_gc()) {
2664 log_info(gc)("Allocation failure was successfully injected");
2665 }
2666 }
2667 }
2668
2669 bool ShenandoahHeap::should_inject_alloc_failure() {
2670 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2671 }
2672
2673 void ShenandoahHeap::initialize_serviceability() {
2674 _memory_pool = new ShenandoahMemoryPool(this);
2675 _cycle_memory_manager.add_pool(_memory_pool);
2676 _stw_memory_manager.add_pool(_memory_pool);
2677 }
2678
2679 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2680 GrowableArray<GCMemoryManager*> memory_managers(2);
2681 memory_managers.append(&_cycle_memory_manager);
2682 memory_managers.append(&_stw_memory_manager);
2683 return memory_managers;
2684 }
2685
2686 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2687 GrowableArray<MemoryPool*> memory_pools(1);
2688 memory_pools.append(_memory_pool);
2689 return memory_pools;
2690 }
2691
2692 MemoryUsage ShenandoahHeap::memory_usage() {
2693 return _memory_pool->get_memory_usage();
2694 }
2695
2696 void ShenandoahHeap::enter_evacuation() {
2697 _oom_evac_handler.enter_evacuation();
2698 }
2699
2700 void ShenandoahHeap::leave_evacuation() {
2701 _oom_evac_handler.leave_evacuation();
2702 }
2703
2704 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2705 _heap(ShenandoahHeap::heap()),
2706 _index(0) {}
2707
2708 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2709 _heap(heap),
2710 _index(0) {}
2711
2712 void ShenandoahRegionIterator::reset() {
2713 _index = 0;
2714 }
2715
2716 bool ShenandoahRegionIterator::has_next() const {
2717 return _index < _heap->num_regions();
2718 }
2719
2720 char ShenandoahHeap::gc_state() const {
2721 return _gc_state.raw_value();
2722 }
2723
2724 void ShenandoahHeap::deduplicate_string(oop str) {
2725 assert(java_lang_String::is_instance(str), "invariant");
2726
2727 if (ShenandoahStringDedup::is_enabled()) {
2728 ShenandoahStringDedup::deduplicate(str);
2729 }
2730 }
2731
2732 const char* ShenandoahHeap::init_mark_event_message() const {
2733 bool update_refs = has_forwarded_objects();
2734 bool proc_refs = process_references();
2735 bool unload_cls = unload_classes();
2736
2737 if (update_refs && proc_refs && unload_cls) {
2738 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2739 } else if (update_refs && proc_refs) {
2740 return "Pause Init Mark (update refs) (process weakrefs)";
2741 } else if (update_refs && unload_cls) {
2742 return "Pause Init Mark (update refs) (unload classes)";
2743 } else if (proc_refs && unload_cls) {
2744 return "Pause Init Mark (process weakrefs) (unload classes)";
2745 } else if (update_refs) {
2746 return "Pause Init Mark (update refs)";
2747 } else if (proc_refs) {
2748 return "Pause Init Mark (process weakrefs)";
2749 } else if (unload_cls) {
2750 return "Pause Init Mark (unload classes)";
2751 } else {
2752 return "Pause Init Mark";
2753 }
2754 }
2755
2756 const char* ShenandoahHeap::final_mark_event_message() const {
2757 bool update_refs = has_forwarded_objects();
2758 bool proc_refs = process_references();
2759 bool unload_cls = unload_classes();
2760
2761 if (update_refs && proc_refs && unload_cls) {
2762 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2763 } else if (update_refs && proc_refs) {
2764 return "Pause Final Mark (update refs) (process weakrefs)";
2765 } else if (update_refs && unload_cls) {
2766 return "Pause Final Mark (update refs) (unload classes)";
2767 } else if (proc_refs && unload_cls) {
2768 return "Pause Final Mark (process weakrefs) (unload classes)";
2769 } else if (update_refs) {
2770 return "Pause Final Mark (update refs)";
2771 } else if (proc_refs) {
2772 return "Pause Final Mark (process weakrefs)";
2773 } else if (unload_cls) {
2774 return "Pause Final Mark (unload classes)";
2775 } else {
2776 return "Pause Final Mark";
2777 }
2778 }
2779
2780 const char* ShenandoahHeap::conc_mark_event_message() const {
2781 bool update_refs = has_forwarded_objects();
2782 bool proc_refs = process_references();
2783 bool unload_cls = unload_classes();
2784
2785 if (update_refs && proc_refs && unload_cls) {
2786 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2787 } else if (update_refs && proc_refs) {
2788 return "Concurrent marking (update refs) (process weakrefs)";
2789 } else if (update_refs && unload_cls) {
2790 return "Concurrent marking (update refs) (unload classes)";
2791 } else if (proc_refs && unload_cls) {
2792 return "Concurrent marking (process weakrefs) (unload classes)";
2793 } else if (update_refs) {
2794 return "Concurrent marking (update refs)";
2795 } else if (proc_refs) {
2796 return "Concurrent marking (process weakrefs)";
2797 } else if (unload_cls) {
2798 return "Concurrent marking (unload classes)";
2799 } else {
2800 return "Concurrent marking";
2801 }
2802 }
2803
2804 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2805 switch (point) {
2806 case _degenerated_unset:
2807 return "Pause Degenerated GC (<UNSET>)";
2808 case _degenerated_traversal:
2809 return "Pause Degenerated GC (Traversal)";
2810 case _degenerated_outside_cycle:
2811 return "Pause Degenerated GC (Outside of Cycle)";
2812 case _degenerated_mark:
2813 return "Pause Degenerated GC (Mark)";
2814 case _degenerated_evac:
2815 return "Pause Degenerated GC (Evacuation)";
2816 case _degenerated_updaterefs:
2817 return "Pause Degenerated GC (Update Refs)";
2818 default:
2819 ShouldNotReachHere();
2820 return "ERROR";
2821 }
2822 }
2823
2824 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2825 #ifdef ASSERT
2826 assert(_liveness_cache != NULL, "sanity");
2827 assert(worker_id < _max_workers, "sanity");
2828 for (uint i = 0; i < num_regions(); i++) {
2829 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2830 }
2831 #endif
2832 return _liveness_cache[worker_id];
2833 }
2834
2835 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2836 assert(worker_id < _max_workers, "sanity");
2837 assert(_liveness_cache != NULL, "sanity");
2838 jushort* ld = _liveness_cache[worker_id];
2839 for (uint i = 0; i < num_regions(); i++) {
2840 ShenandoahHeapRegion* r = get_region(i);
2841 jushort live = ld[i];
2842 if (live > 0) {
2843 r->increase_live_data_gc_words(live);
2844 ld[i] = 0;
2845 }
2846 }
2847 }
2848
2849 size_t ShenandoahHeap::obj_size(oop obj) const {
2850 return CollectedHeap::obj_size(obj) + ShenandoahBrooksPointer::word_size();
2851 }
2852
2853 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2854 return ShenandoahBrooksPointer::byte_size();
2855 }
2856
2857 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
2858 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
2859 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
2860 }