1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/memAllocator.hpp"
30 #include "gc/shared/parallelCleaning.hpp"
31 #include "gc/shared/plab.hpp"
32
33 #include "gc/shenandoah/brooksPointer.hpp"
34 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
35 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
37 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
39 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
40 #include "gc/shenandoah/shenandoahControlThread.hpp"
41 #include "gc/shenandoah/shenandoahFreeSet.hpp"
42 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
43 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
45 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
46 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
47 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
48 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
49 #include "gc/shenandoah/shenandoahMetrics.hpp"
50 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
51 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
52 #include "gc/shenandoah/shenandoahPacer.hpp"
53 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
54 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
55 #include "gc/shenandoah/shenandoahStringDedup.hpp"
56 #include "gc/shenandoah/shenandoahUtils.hpp"
57 #include "gc/shenandoah/shenandoahVerifier.hpp"
58 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
59 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
60 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
67
68 #include "memory/metaspace.hpp"
69 #include "runtime/vmThread.hpp"
70 #include "services/mallocTracker.hpp"
71
72 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
73
74 #ifdef ASSERT
75 template <class T>
76 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
77 T o = RawAccess<>::oop_load(p);
78 if (! CompressedOops::is_null(o)) {
79 oop obj = CompressedOops::decode_not_null(o);
80 shenandoah_assert_not_forwarded(p, obj);
81 }
82 }
83
84 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
85 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
86 #endif
87
88 const char* ShenandoahHeap::name() const {
89 return "Shenandoah";
90 }
91
92 class ShenandoahPretouchTask : public AbstractGangTask {
93 private:
94 ShenandoahRegionIterator _regions;
95 const size_t _bitmap_size;
96 const size_t _page_size;
97 char* _bitmap0_base;
98 char* _bitmap1_base;
99 public:
100 ShenandoahPretouchTask(char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
101 size_t page_size) :
102 AbstractGangTask("Shenandoah PreTouch"),
103 _bitmap_size(bitmap_size),
104 _page_size(page_size),
105 _bitmap0_base(bitmap0_base),
106 _bitmap1_base(bitmap1_base) {
107 }
108
109 virtual void work(uint worker_id) {
110 ShenandoahHeapRegion* r = _regions.next();
111 while (r != NULL) {
112 os::pretouch_memory(r->bottom(), r->end(), _page_size);
113
114 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
115 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
116 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
117
118 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
119 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
120
121 r = _regions.next();
122 }
123 }
124 };
125
126 jint ShenandoahHeap::initialize() {
127
128 BrooksPointer::initial_checks();
129
130 initialize_heuristics();
131
132 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
133 size_t max_byte_size = collector_policy()->max_heap_byte_size();
134 size_t heap_alignment = collector_policy()->heap_alignment();
135
136 if (ShenandoahAlwaysPreTouch) {
137 // Enabled pre-touch means the entire heap is committed right away.
138 init_byte_size = max_byte_size;
139 }
140
141 Universe::check_alignment(max_byte_size,
142 ShenandoahHeapRegion::region_size_bytes(),
143 "shenandoah heap");
144 Universe::check_alignment(init_byte_size,
145 ShenandoahHeapRegion::region_size_bytes(),
146 "shenandoah heap");
147
148 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
149 heap_alignment);
150 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
151
152 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
153
154 _num_regions = ShenandoahHeapRegion::region_count();
155 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
156 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
157 _committed = _initial_size;
158
159 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
160 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
161 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
162 }
163
164 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
165 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
166
167 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
168 _free_set = new ShenandoahFreeSet(this, _num_regions);
169
170 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
171
172 if (ShenandoahPacing) {
173 _pacer = new ShenandoahPacer(this);
174 _pacer->setup_for_idle();
175 } else {
176 _pacer = NULL;
177 }
178
179 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
180 "misaligned heap: "PTR_FORMAT, p2i(base()));
181
182 ShenandoahBarrierSet::satb_mark_queue_set().set_buffer_size(ShenandoahSATBBufferSize);
183
184 // The call below uses stuff (the SATB* things) that are in G1, but probably
185 // belong into a shared location.
186 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
187 SATB_Q_CBL_mon,
188 SATB_Q_FL_lock,
189 20 /*G1SATBProcessCompletedThreshold */,
190 60 /* G1SATBBufferEnqueueingThresholdPercent */,
191 Shared_SATB_Q_lock);
192
193 // Reserve space for prev and next bitmap.
194 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
195 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
196 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
197 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
198
199 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
200
201 guarantee(bitmap_bytes_per_region != 0,
202 "Bitmap bytes per region should not be zero");
203 guarantee(is_power_of_2(bitmap_bytes_per_region),
204 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
205
206 if (bitmap_page_size > bitmap_bytes_per_region) {
207 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
208 _bitmap_bytes_per_slice = bitmap_page_size;
209 } else {
210 _bitmap_regions_per_slice = 1;
211 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
212 }
213
214 guarantee(_bitmap_regions_per_slice >= 1,
215 "Should have at least one region per slice: " SIZE_FORMAT,
216 _bitmap_regions_per_slice);
217
218 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
219 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
220 _bitmap_bytes_per_slice, bitmap_page_size);
221
222 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
223 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
224 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
225
226 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
227 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
228 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
229
230 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
231 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
232 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
233 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
234 "couldn't allocate initial bitmap");
235 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
236 "couldn't allocate initial bitmap");
237
238 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
239
240 if (ShenandoahVerify) {
241 ReservedSpace verify_bitmap(_bitmap_size, page_size);
242 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
243 "couldn't allocate verification bitmap");
244 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
245 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
246 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
247 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
248 }
249
250 _complete_marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap0_region, _num_regions);
251 _next_marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap1_region, _num_regions);
252
253 {
254 ShenandoahHeapLocker locker(lock());
255 for (size_t i = 0; i < _num_regions; i++) {
256 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
257 (HeapWord*) pgc_rs.base() + reg_size_words * i,
258 reg_size_words,
259 i,
260 i < num_committed_regions);
261
262 _complete_marking_context->set_top_at_mark_start(i, r->bottom());
263 _next_marking_context->set_top_at_mark_start(i, r->bottom());
264 _regions[i] = r;
265 assert(!collection_set()->is_in(i), "New region should not be in collection set");
266 }
267
268 _free_set->rebuild();
269 }
270
271 if (ShenandoahAlwaysPreTouch) {
272 assert (!AlwaysPreTouch, "Should have been overridden");
273
274 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
275 // before initialize() below zeroes it with initializing thread. For any given region,
276 // we touch the region and the corresponding bitmaps from the same thread.
277 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
278
279 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
280 _num_regions, page_size);
281 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
282 _workers->run_task(&cl);
283 }
284
285
286 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
287 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
288 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
289 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
290 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
291
292 _traversal_gc = heuristics()->can_do_traversal_gc() ?
293 new ShenandoahTraversalGC(this, _num_regions) :
294 NULL;
295
296 _monitoring_support = new ShenandoahMonitoringSupport(this);
297
298 _phase_timings = new ShenandoahPhaseTimings();
299
300 if (ShenandoahAllocationTrace) {
301 _alloc_tracker = new ShenandoahAllocTracker();
302 }
303
304 ShenandoahStringDedup::initialize();
305
306 _control_thread = new ShenandoahControlThread();
307
308 ShenandoahCodeRoots::initialize();
309
310 log_info(gc, init)("Safepointing mechanism: %s",
311 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
312 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
313
314 return JNI_OK;
315 }
316
317 void ShenandoahHeap::initialize_heuristics() {
318 if (ShenandoahGCHeuristics != NULL) {
319 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
320 _heuristics = new ShenandoahAggressiveHeuristics();
321 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
322 _heuristics = new ShenandoahStaticHeuristics();
323 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
324 _heuristics = new ShenandoahAdaptiveHeuristics();
325 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
326 _heuristics = new ShenandoahPassiveHeuristics();
327 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
328 _heuristics = new ShenandoahCompactHeuristics();
329 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
330 _heuristics = new ShenandoahTraversalHeuristics();
331 } else {
332 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
333 }
334
335 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
336 vm_exit_during_initialization(
337 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
338 _heuristics->name()));
339 }
340 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
341 vm_exit_during_initialization(
342 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
343 _heuristics->name()));
344 }
345
346 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
347 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
348 }
349 log_info(gc, init)("Shenandoah heuristics: %s",
350 _heuristics->name());
351 } else {
352 ShouldNotReachHere();
353 }
354
355 }
356
357 #ifdef _MSC_VER
358 #pragma warning( push )
359 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
360 #endif
361
362 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
363 CollectedHeap(),
364 _shenandoah_policy(policy),
365 _soft_ref_policy(),
366 _regions(NULL),
367 _free_set(NULL),
368 _collection_set(NULL),
369 _update_refs_iterator(this),
370 _scm(new ShenandoahConcurrentMark()),
371 _full_gc(new ShenandoahMarkCompact()),
372 _traversal_gc(NULL),
373 _verifier(NULL),
374 _pacer(NULL),
375 _phase_timings(NULL),
376 _alloc_tracker(NULL),
377 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
378 _safepoint_workers(NULL),
379 _used(0),
380 _complete_marking_context(NULL),
381 _next_marking_context(NULL),
382 _bytes_allocated_since_gc_start(0),
383 _ref_processor(NULL),
384 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
385 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
386 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
387 _memory_pool(NULL),
388 #ifdef ASSERT
389 _heap_expansion_count(0),
390 #endif
391 _alloc_seq_at_last_gc_start(0),
392 _alloc_seq_at_last_gc_end(0),
393 _used_at_last_gc(0) {
394 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
395 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
396
397 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
398
399 _max_workers = MAX2(_max_workers, 1U);
400 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
401 /* are_GC_task_threads */true,
402 /* are_ConcurrentGC_threads */false);
403 if (_workers == NULL) {
404 vm_exit_during_initialization("Failed necessary allocation.");
405 } else {
406 _workers->initialize_workers();
407 }
408
409 if (ParallelSafepointCleanupThreads > 1) {
410 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
411 ParallelSafepointCleanupThreads,
412 false, false);
413 _safepoint_workers->initialize_workers();
414 }
415 }
416
417 #ifdef _MSC_VER
418 #pragma warning( pop )
419 #endif
420
421 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
422 private:
423 ShenandoahRegionIterator _regions;
424
425 public:
426 ShenandoahResetNextBitmapTask() :
427 AbstractGangTask("Parallel Reset Bitmap Task") {}
428
429 void work(uint worker_id) {
430 ShenandoahHeapRegion* region = _regions.next();
431 ShenandoahHeap* heap = ShenandoahHeap::heap();
432 ShenandoahMarkingContext* const ctx = heap->next_marking_context();
433 while (region != NULL) {
434 if (heap->is_bitmap_slice_committed(region)) {
435 HeapWord* bottom = region->bottom();
436 HeapWord* top = ctx->top_at_mark_start(region->region_number());
437 if (top > bottom) {
438 ctx->clear_bitmap(bottom, top);
439 }
440 assert(ctx->is_bitmap_clear_range(bottom, region->end()), "must be clear");
441 }
442 region = _regions.next();
443 }
444 }
445 };
446
447 void ShenandoahHeap::reset_next_mark_bitmap() {
448 assert_gc_workers(_workers->active_workers());
449
450 ShenandoahResetNextBitmapTask task;
451 _workers->run_task(&task);
452 }
453
454 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
455 private:
456 ShenandoahHeapRegionSetIterator& _regions;
457
458 public:
459 ShenandoahResetNextBitmapTraversalTask(ShenandoahHeapRegionSetIterator& regions) :
460 AbstractGangTask("Parallel Reset Bitmap Task for Traversal"),
461 _regions(regions) {}
462
463 void work(uint worker_id) {
464 ShenandoahHeap* heap = ShenandoahHeap::heap();
465 ShenandoahHeapRegion* region = _regions.claim_next();
466 ShenandoahMarkingContext* const next_ctx = heap->next_marking_context();
467 ShenandoahMarkingContext* const compl_ctx = heap->complete_marking_context();
468 while (region != NULL) {
469 assert(!region->is_trash() && !region->is_empty_uncommitted(), "sanity");
470 assert(heap->is_bitmap_slice_committed(region), "sanity");
471 HeapWord* bottom = region->bottom();
472 HeapWord* top = next_ctx->top_at_mark_start(region->region_number());
473 if (top > bottom) {
474 compl_ctx->mark_bit_map()->copy_from(next_ctx->mark_bit_map(), MemRegion(bottom, top));
475 compl_ctx->set_top_at_mark_start(region->region_number(), top);
476 next_ctx->clear_bitmap(bottom, top);
477 next_ctx->set_top_at_mark_start(region->region_number(), bottom);
478 }
479 assert(next_ctx->is_bitmap_clear_range(region->bottom(), region->end()),
480 "need clear next bitmap");
481 region = _regions.claim_next();
482 }
483 }
484 };
485
486 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
487 assert_gc_workers(_workers->active_workers());
488
489 ShenandoahHeapRegionSet* regions = traversal_gc()->traversal_set();
490 ShenandoahHeapRegionSetIterator iter(regions);
491 ShenandoahResetNextBitmapTraversalTask task(iter);
492 _workers->run_task(&task);
493 assert(next_marking_context()->is_bitmap_clear(), "need clean mark bitmap");
494 }
495
496 void ShenandoahHeap::print_on(outputStream* st) const {
497 st->print_cr("Shenandoah Heap");
498 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
499 capacity() / K, committed() / K, used() / K);
500 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
501 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
502
503 st->print("Status: ");
504 if (has_forwarded_objects()) st->print("has forwarded objects, ");
505 if (is_concurrent_mark_in_progress()) st->print("marking, ");
506 if (is_evacuation_in_progress()) st->print("evacuating, ");
507 if (is_update_refs_in_progress()) st->print("updating refs, ");
508 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
509 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
510 if (is_full_gc_in_progress()) st->print("full gc, ");
511 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
512
513 if (cancelled_gc()) {
514 st->print("cancelled");
515 } else {
516 st->print("not cancelled");
517 }
518 st->cr();
519
520 st->print_cr("Reserved region:");
521 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
522 p2i(reserved_region().start()),
523 p2i(reserved_region().end()));
524
525 st->cr();
526 MetaspaceUtils::print_on(st);
527
528 if (Verbose) {
529 print_heap_regions_on(st);
530 }
531 }
532
533 class ShenandoahInitGCLABClosure : public ThreadClosure {
534 public:
535 void do_thread(Thread* thread) {
536 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread())) {
537 ShenandoahThreadLocalData::initialize_gclab(thread);
538 }
539 }
540 };
541
542 void ShenandoahHeap::post_initialize() {
543 CollectedHeap::post_initialize();
544 MutexLocker ml(Threads_lock);
545
546 ShenandoahInitGCLABClosure init_gclabs;
547 Threads::threads_do(&init_gclabs);
548 _workers->threads_do(&init_gclabs);
549
550 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
551 // Now, we will let WorkGang to initialize gclab when new worker is created.
552 _workers->set_initialize_gclab();
553
554 _scm->initialize(_max_workers);
555 _full_gc->initialize(_gc_timer);
556
557 ref_processing_init();
558
559 _heuristics->initialize();
560 }
561
562 size_t ShenandoahHeap::used() const {
563 return OrderAccess::load_acquire(&_used);
564 }
565
566 size_t ShenandoahHeap::committed() const {
567 OrderAccess::acquire();
568 return _committed;
569 }
570
571 void ShenandoahHeap::increase_committed(size_t bytes) {
572 assert_heaplock_or_safepoint();
573 _committed += bytes;
574 }
575
576 void ShenandoahHeap::decrease_committed(size_t bytes) {
577 assert_heaplock_or_safepoint();
578 _committed -= bytes;
579 }
580
581 void ShenandoahHeap::increase_used(size_t bytes) {
582 Atomic::add(bytes, &_used);
583 }
584
585 void ShenandoahHeap::set_used(size_t bytes) {
586 OrderAccess::release_store_fence(&_used, bytes);
587 }
588
589 void ShenandoahHeap::decrease_used(size_t bytes) {
590 assert(used() >= bytes, "never decrease heap size by more than we've left");
591 Atomic::sub(bytes, &_used);
592 }
593
594 void ShenandoahHeap::increase_allocated(size_t bytes) {
595 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
596 }
597
598 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
599 size_t bytes = words * HeapWordSize;
600 if (!waste) {
601 increase_used(bytes);
602 }
603 increase_allocated(bytes);
604 if (ShenandoahPacing) {
605 control_thread()->pacing_notify_alloc(words);
606 if (waste) {
607 pacer()->claim_for_alloc(words, true);
608 }
609 }
610 }
611
612 size_t ShenandoahHeap::capacity() const {
613 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
614 }
615
616 bool ShenandoahHeap::is_maximal_no_gc() const {
617 Unimplemented();
618 return true;
619 }
620
621 size_t ShenandoahHeap::max_capacity() const {
622 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
623 }
624
625 size_t ShenandoahHeap::initial_capacity() const {
626 return _initial_size;
627 }
628
629 bool ShenandoahHeap::is_in(const void* p) const {
630 HeapWord* heap_base = (HeapWord*) base();
631 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
632 return p >= heap_base && p < last_region_end;
633 }
634
635 bool ShenandoahHeap::is_scavengable(oop p) {
636 return true;
637 }
638
639 void ShenandoahHeap::op_uncommit(double shrink_before) {
640 assert (ShenandoahUncommit, "should be enabled");
641
642 size_t count = 0;
643 for (size_t i = 0; i < num_regions(); i++) {
644 ShenandoahHeapRegion* r = get_region(i);
645 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
646 ShenandoahHeapLocker locker(lock());
647 if (r->is_empty_committed()) {
648 r->make_uncommitted();
649 count++;
650 }
651 }
652 SpinPause(); // allow allocators to take the lock
653 }
654
655 if (count > 0) {
656 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
657 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
658 control_thread()->notify_heap_changed();
659 }
660 }
661
662 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
663 // New object should fit the GCLAB size
664 size_t min_size = MAX2(size, PLAB::min_size());
665
666 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
667 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
668 new_size = MIN2(new_size, PLAB::max_size());
669 new_size = MAX2(new_size, PLAB::min_size());
670
671 // Record new heuristic value even if we take any shortcut. This captures
672 // the case when moderately-sized objects always take a shortcut. At some point,
673 // heuristics should catch up with them.
674 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
675
676 if (new_size < size) {
677 // New size still does not fit the object. Fall back to shared allocation.
678 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
679 return NULL;
680 }
681
682 // Retire current GCLAB, and allocate a new one.
683 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
684 gclab->retire();
685
686 size_t actual_size = 0;
687 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
688 if (gclab_buf == NULL) {
689 return NULL;
690 }
691
692 assert (size <= actual_size, "allocation should fit");
693
694 if (ZeroTLAB) {
695 // ..and clear it.
696 Copy::zero_to_words(gclab_buf, actual_size);
697 } else {
698 // ...and zap just allocated object.
699 #ifdef ASSERT
700 // Skip mangling the space corresponding to the object header to
701 // ensure that the returned space is not considered parsable by
702 // any concurrent GC thread.
703 size_t hdr_size = oopDesc::header_size();
704 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
705 #endif // ASSERT
706 }
707 gclab->set_buf(gclab_buf, actual_size);
708 return gclab->allocate(size);
709 }
710
711 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
712 size_t requested_size,
713 size_t* actual_size) {
714 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_tlab(min_size, requested_size);
715 HeapWord* res = allocate_memory(req);
716 if (res != NULL) {
717 *actual_size = req.actual_size();
718 } else {
719 *actual_size = 0;
720 }
721 return res;
722 }
723
724 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
725 size_t word_size,
726 size_t* actual_size) {
727 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_gclab(min_size, word_size);
728 HeapWord* res = allocate_memory(req);
729 if (res != NULL) {
730 *actual_size = req.actual_size();
731 } else {
732 *actual_size = 0;
733 }
734 return res;
735 }
736
737 ShenandoahHeap* ShenandoahHeap::heap() {
738 CollectedHeap* heap = Universe::heap();
739 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
740 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
741 return (ShenandoahHeap*) heap;
742 }
743
744 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
745 CollectedHeap* heap = Universe::heap();
746 return (ShenandoahHeap*) heap;
747 }
748
749 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocationRequest& req) {
750 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
751
752 intptr_t pacer_epoch = 0;
753 bool in_new_region = false;
754 HeapWord* result = NULL;
755
756 if (req.is_mutator_alloc()) {
757 if (ShenandoahPacing) {
758 pacer()->pace_for_alloc(req.size());
759 pacer_epoch = pacer()->epoch();
760 }
761
762 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
763 result = allocate_memory_under_lock(req, in_new_region);
764 }
765
766 // Allocation failed, block until control thread reacted, then retry allocation.
767 //
768 // It might happen that one of the threads requesting allocation would unblock
769 // way later after GC happened, only to fail the second allocation, because
770 // other threads have already depleted the free storage. In this case, a better
771 // strategy is to try again, as long as GC makes progress.
772 //
773 // Then, we need to make sure the allocation was retried after at least one
774 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
775
776 size_t tries = 0;
777
778 while (result == NULL && last_gc_made_progress()) {
779 tries++;
780 control_thread()->handle_alloc_failure(req.size());
781 result = allocate_memory_under_lock(req, in_new_region);
782 }
783
784 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
785 tries++;
786 control_thread()->handle_alloc_failure(req.size());
787 result = allocate_memory_under_lock(req, in_new_region);
788 }
789
790 } else {
791 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
792 result = allocate_memory_under_lock(req, in_new_region);
793 // Do not call handle_alloc_failure() here, because we cannot block.
794 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
795 }
796
797 if (in_new_region) {
798 control_thread()->notify_heap_changed();
799 }
800
801 if (result != NULL) {
802 size_t requested = req.size();
803 size_t actual = req.actual_size();
804
805 assert (req.is_lab_alloc() || (requested == actual),
806 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
807 alloc_type_to_string(req.type()), requested, actual);
808
809 if (req.is_mutator_alloc()) {
810 notify_mutator_alloc_words(actual, false);
811
812 // If we requested more than we were granted, give the rest back to pacer.
813 // This only matters if we are in the same pacing epoch: do not try to unpace
814 // over the budget for the other phase.
815 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
816 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
817 }
818 } else {
819 increase_used(actual*HeapWordSize);
820 }
821 }
822
823 return result;
824 }
825
826 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocationRequest& req, bool& in_new_region) {
827 ShenandoahHeapLocker locker(lock());
828 return _free_set->allocate(req, in_new_region);
829 }
830
831 class ShenandoahObjAllocator : public ObjAllocator {
832 public:
833 ShenandoahObjAllocator(Klass* klass, size_t word_size, Thread* thread) :
834 ObjAllocator(klass, word_size, thread) {}
835
836 virtual HeapWord* mem_allocate(Allocation& allocation) {
837 // Allocate object.
838 _word_size += BrooksPointer::word_size();
839 HeapWord* result = ObjAllocator::mem_allocate(allocation);
840 _word_size -= BrooksPointer::word_size();
841 // Initialize brooks-pointer
842 if (result != NULL) {
843 result += BrooksPointer::word_size();
844 BrooksPointer::initialize(oop(result));
845 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
846 }
847 return result;
848 }
849 };
850
851 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
852 ShenandoahObjAllocator allocator(klass, size, THREAD);
853 return allocator.allocate();
854 }
855
856 class ShenandoahObjArrayAllocator : public ObjArrayAllocator {
857 public:
858 ShenandoahObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero,
859 Thread* thread) :
860 ObjArrayAllocator(klass, word_size, length, do_zero, thread) {}
861
862 virtual HeapWord* mem_allocate(Allocation& allocation) {
863 // Allocate object.
864 _word_size += BrooksPointer::word_size();
865 HeapWord* result = ObjArrayAllocator::mem_allocate(allocation);
866 _word_size -= BrooksPointer::word_size();
867 if (result != NULL) {
868 result += BrooksPointer::word_size();
869 BrooksPointer::initialize(oop(result));
870 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
871 }
872 return result;
873 }
874
875 };
876
877 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
878 ShenandoahObjArrayAllocator allocator(klass, size, length, do_zero, THREAD);
879 return allocator.allocate();
880 }
881
882 class ShenandoahClassAllocator : public ClassAllocator {
883 public:
884 ShenandoahClassAllocator(Klass* klass, size_t word_size, Thread* thread) :
885 ClassAllocator(klass, word_size, thread) {}
886
887 virtual HeapWord* mem_allocate(Allocation& allocation) {
888 _word_size += BrooksPointer::word_size();
889 HeapWord* result = ClassAllocator::mem_allocate(allocation);
890 _word_size -= BrooksPointer::word_size();
891 if (result != NULL) {
892 result += BrooksPointer::word_size();
893 BrooksPointer::initialize(oop(result));
894 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
895 }
896 return result;
897 }
898
899 };
900
901 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
902 ShenandoahClassAllocator allocator(klass, size, THREAD);
903 return allocator.allocate();
904 }
905
906 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
907 bool* gc_overhead_limit_was_exceeded) {
908 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_shared(size);
909 return allocate_memory(req);
910 }
911
912 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
913 HeapWord* obj = tlab_post_allocation_setup(start);
914 CollectedHeap::fill_with_object(obj, end);
915 }
916
917 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
918 private:
919 ShenandoahHeap* _heap;
920 Thread* _thread;
921 public:
922 ShenandoahEvacuateUpdateRootsClosure() :
923 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
924 }
925
926 private:
927 template <class T>
928 void do_oop_work(T* p) {
929 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
930
931 T o = RawAccess<>::oop_load(p);
932 if (! CompressedOops::is_null(o)) {
933 oop obj = CompressedOops::decode_not_null(o);
934 if (_heap->in_collection_set(obj)) {
935 shenandoah_assert_marked_complete(p, obj);
936 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
937 if (oopDesc::unsafe_equals(resolved, obj)) {
938 resolved = _heap->evacuate_object(obj, _thread);
939 }
940 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
941 }
942 }
943 }
944
945 public:
946 void do_oop(oop* p) {
947 do_oop_work(p);
948 }
949 void do_oop(narrowOop* p) {
950 do_oop_work(p);
951 }
952 };
953
954 class ShenandoahEvacuateRootsClosure: public BasicOopIterateClosure {
955 private:
956 ShenandoahHeap* _heap;
957 Thread* _thread;
958 public:
959 ShenandoahEvacuateRootsClosure() :
960 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
961 }
962
963 private:
964 template <class T>
965 void do_oop_work(T* p) {
966 T o = RawAccess<>::oop_load(p);
967 if (! CompressedOops::is_null(o)) {
968 oop obj = CompressedOops::decode_not_null(o);
969 if (_heap->in_collection_set(obj)) {
970 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
971 if (oopDesc::unsafe_equals(resolved, obj)) {
972 _heap->evacuate_object(obj, _thread);
973 }
974 }
975 }
976 }
977
978 public:
979 void do_oop(oop* p) {
980 do_oop_work(p);
981 }
982 void do_oop(narrowOop* p) {
983 do_oop_work(p);
984 }
985 };
986
987 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
988 private:
989 ShenandoahHeap* const _heap;
990 Thread* const _thread;
991 public:
992 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
993 _heap(heap), _thread(Thread::current()) {}
994
995 void do_object(oop p) {
996 shenandoah_assert_marked_complete(NULL, p);
997 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
998 _heap->evacuate_object(p, _thread);
999 }
1000 }
1001 };
1002
1003 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
1004 private:
1005 ShenandoahHeap* const _sh;
1006 ShenandoahCollectionSet* const _cs;
1007
1008 public:
1009 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
1010 ShenandoahCollectionSet* cs) :
1011 AbstractGangTask("Parallel Evacuation Task"),
1012 _sh(sh),
1013 _cs(cs)
1014 {}
1015
1016 void work(uint worker_id) {
1017 ShenandoahWorkerSession worker_session(worker_id);
1018 ShenandoahEvacOOMScope oom_evac_scope;
1019 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
1020
1021 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
1022 ShenandoahHeapRegion* r;
1023 while ((r =_cs->claim_next()) != NULL) {
1024 assert(r->has_live(), "all-garbage regions are reclaimed early");
1025 _sh->marked_object_iterate(r, &cl);
1026
1027 if (ShenandoahPacing) {
1028 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1029 }
1030
1031 if (_sh->check_cancelled_gc_and_yield()) {
1032 break;
1033 }
1034 }
1035 }
1036 };
1037
1038 void ShenandoahHeap::trash_cset_regions() {
1039 ShenandoahHeapLocker locker(lock());
1040
1041 ShenandoahCollectionSet* set = collection_set();
1042 ShenandoahHeapRegion* r;
1043 set->clear_current_index();
1044 while ((r = set->next()) != NULL) {
1045 r->make_trash();
1046 }
1047 collection_set()->clear();
1048 }
1049
1050 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1051 st->print_cr("Heap Regions:");
1052 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1053 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1054 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1055 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1056
1057 for (size_t i = 0; i < num_regions(); i++) {
1058 get_region(i)->print_on(st);
1059 }
1060 }
1061
1062 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1063 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1064
1065 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
1066 size_t size = humongous_obj->size() + BrooksPointer::word_size();
1067 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1068 size_t index = start->region_number() + required_regions - 1;
1069
1070 assert(!start->has_live(), "liveness must be zero");
1071
1072 for(size_t i = 0; i < required_regions; i++) {
1073 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1074 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1075 ShenandoahHeapRegion* region = get_region(index --);
1076
1077 assert(region->is_humongous(), "expect correct humongous start or continuation");
1078 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1079
1080 region->make_trash();
1081 }
1082 }
1083
1084 #ifdef ASSERT
1085 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1086 bool heap_region_do(ShenandoahHeapRegion* r) {
1087 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1088 return false;
1089 }
1090 };
1091 #endif
1092
1093 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1094 if (!cancelled_gc()) {
1095 make_parsable(true);
1096
1097 if (ShenandoahVerify) {
1098 verifier()->verify_after_concmark();
1099 }
1100
1101 trash_cset_regions();
1102
1103 // NOTE: This needs to be done during a stop the world pause, because
1104 // putting regions into the collection set concurrently with Java threads
1105 // will create a race. In particular, acmp could fail because when we
1106 // resolve the first operand, the containing region might not yet be in
1107 // the collection set, and thus return the original oop. When the 2nd
1108 // operand gets resolved, the region could be in the collection set
1109 // and the oop gets evacuated. If both operands have originally been
1110 // the same, we get false negatives.
1111
1112 {
1113 ShenandoahHeapLocker locker(lock());
1114 _collection_set->clear();
1115 _free_set->clear();
1116
1117 #ifdef ASSERT
1118 ShenandoahCheckCollectionSetClosure ccsc;
1119 heap_region_iterate(&ccsc);
1120 #endif
1121
1122 heuristics()->choose_collection_set(_collection_set);
1123
1124 _free_set->rebuild();
1125 }
1126
1127 if (ShenandoahVerify) {
1128 verifier()->verify_before_evacuation();
1129 }
1130 }
1131 }
1132
1133
1134 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1135 public:
1136 void do_thread(Thread* thread) {
1137 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1138 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1139 gclab->retire();
1140 }
1141 };
1142
1143 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1144 if (UseTLAB) {
1145 CollectedHeap::ensure_parsability(retire_tlabs);
1146 }
1147 ShenandoahRetireGCLABClosure cl;
1148 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1149 cl.do_thread(t);
1150 }
1151 workers()->threads_do(&cl);
1152 }
1153
1154 void ShenandoahHeap::resize_tlabs() {
1155 CollectedHeap::resize_all_tlabs();
1156 }
1157
1158 void ShenandoahHeap::accumulate_statistics_tlabs() {
1159 CollectedHeap::accumulate_statistics_all_tlabs();
1160 }
1161
1162 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1163 ShenandoahRootEvacuator* _rp;
1164 public:
1165
1166 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1167 AbstractGangTask("Shenandoah evacuate and update roots"),
1168 _rp(rp)
1169 {
1170 // Nothing else to do.
1171 }
1172
1173 void work(uint worker_id) {
1174 ShenandoahWorkerSession worker_session(worker_id);
1175 ShenandoahEvacOOMScope oom_evac_scope;
1176 ShenandoahEvacuateUpdateRootsClosure cl;
1177
1178 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1179 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1180 }
1181 };
1182
1183 class ShenandoahFixRootsTask : public AbstractGangTask {
1184 ShenandoahRootEvacuator* _rp;
1185 public:
1186
1187 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1188 AbstractGangTask("Shenandoah update roots"),
1189 _rp(rp)
1190 {
1191 // Nothing else to do.
1192 }
1193
1194 void work(uint worker_id) {
1195 ShenandoahWorkerSession worker_session(worker_id);
1196 ShenandoahEvacOOMScope oom_evac_scope;
1197 ShenandoahUpdateRefsClosure cl;
1198 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1199
1200 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1201 }
1202 };
1203
1204 void ShenandoahHeap::evacuate_and_update_roots() {
1205
1206 #if defined(COMPILER2) || INCLUDE_JVMCI
1207 DerivedPointerTable::clear();
1208 #endif
1209 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1210
1211 {
1212 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1213 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1214 workers()->run_task(&roots_task);
1215 }
1216
1217 #if defined(COMPILER2) || INCLUDE_JVMCI
1218 DerivedPointerTable::update_pointers();
1219 #endif
1220 if (cancelled_gc()) {
1221 fixup_roots();
1222 }
1223 }
1224
1225 void ShenandoahHeap::fixup_roots() {
1226 assert(cancelled_gc(), "Only after concurrent cycle failed");
1227
1228 // If initial evacuation has been cancelled, we need to update all references
1229 // after all workers have finished. Otherwise we might run into the following problem:
1230 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1231 // GC thread 2 evacuates the same object X to to-space
1232 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1233 // clear() and update_pointers() must always be called in pairs,
1234 // cannot nest with above clear()/update_pointers().
1235 #if defined(COMPILER2) || INCLUDE_JVMCI
1236 DerivedPointerTable::clear();
1237 #endif
1238 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1239 ShenandoahFixRootsTask update_roots_task(&rp);
1240 workers()->run_task(&update_roots_task);
1241 #if defined(COMPILER2) || INCLUDE_JVMCI
1242 DerivedPointerTable::update_pointers();
1243 #endif
1244 }
1245
1246 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1247 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1248
1249 CodeBlobToOopClosure blobsCl(cl, false);
1250 CLDToOopClosure cldCl(cl);
1251
1252 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1253 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1254 }
1255
1256 bool ShenandoahHeap::supports_tlab_allocation() const {
1257 return true;
1258 }
1259
1260 // Returns size in bytes
1261 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1262 if (ShenandoahElasticTLAB) {
1263 // With Elastic TLABs, return the max allowed size, and let the allocation path
1264 // figure out the safe size for current allocation.
1265 return ShenandoahHeapRegion::max_tlab_size_bytes();
1266 } else {
1267 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1268 }
1269 }
1270
1271 size_t ShenandoahHeap::max_tlab_size() const {
1272 // Returns size in words
1273 return ShenandoahHeapRegion::max_tlab_size_words();
1274 }
1275
1276 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1277 public:
1278 void do_thread(Thread* thread) {
1279 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1280 gclab->retire();
1281 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1282 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1283 }
1284 }
1285 };
1286
1287 void ShenandoahHeap::retire_and_reset_gclabs() {
1288 ShenandoahRetireAndResetGCLABClosure cl;
1289 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1290 cl.do_thread(t);
1291 }
1292 workers()->threads_do(&cl);
1293 }
1294
1295 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1296 return true;
1297 }
1298
1299 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1300 // Overridden to do nothing.
1301 return new_obj;
1302 }
1303
1304 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1305 return true;
1306 }
1307
1308 bool ShenandoahHeap::card_mark_must_follow_store() const {
1309 return false;
1310 }
1311
1312 void ShenandoahHeap::collect(GCCause::Cause cause) {
1313 control_thread()->handle_explicit_gc(cause);
1314 }
1315
1316 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1317 //assert(false, "Shouldn't need to do full collections");
1318 }
1319
1320 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1321 Unimplemented();
1322 return NULL;
1323
1324 }
1325
1326 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1327 return _shenandoah_policy;
1328 }
1329
1330
1331 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1332 Space* sp = heap_region_containing(addr);
1333 if (sp != NULL) {
1334 return sp->block_start(addr);
1335 }
1336 return NULL;
1337 }
1338
1339 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1340 Space* sp = heap_region_containing(addr);
1341 assert(sp != NULL, "block_size of address outside of heap");
1342 return sp->block_size(addr);
1343 }
1344
1345 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1346 Space* sp = heap_region_containing(addr);
1347 return sp->block_is_obj(addr);
1348 }
1349
1350 jlong ShenandoahHeap::millis_since_last_gc() {
1351 return 0;
1352 }
1353
1354 void ShenandoahHeap::prepare_for_verify() {
1355 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1356 make_parsable(false);
1357 }
1358 }
1359
1360 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1361 workers()->print_worker_threads_on(st);
1362 if (ShenandoahStringDedup::is_enabled()) {
1363 ShenandoahStringDedup::print_worker_threads_on(st);
1364 }
1365 }
1366
1367 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1368 workers()->threads_do(tcl);
1369 if (ShenandoahStringDedup::is_enabled()) {
1370 ShenandoahStringDedup::threads_do(tcl);
1371 }
1372 }
1373
1374 void ShenandoahHeap::print_tracing_info() const {
1375 LogTarget(Info, gc, stats) lt;
1376 if (lt.is_enabled()) {
1377 ResourceMark rm;
1378 LogStream ls(lt);
1379
1380 phase_timings()->print_on(&ls);
1381
1382 ls.cr();
1383 ls.cr();
1384
1385 shenandoahPolicy()->print_gc_stats(&ls);
1386
1387 ls.cr();
1388 ls.cr();
1389
1390 if (ShenandoahPacing) {
1391 pacer()->print_on(&ls);
1392 }
1393
1394 ls.cr();
1395 ls.cr();
1396
1397 if (ShenandoahAllocationTrace) {
1398 assert(alloc_tracker() != NULL, "Must be");
1399 alloc_tracker()->print_on(&ls);
1400 } else {
1401 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1402 }
1403 }
1404 }
1405
1406 void ShenandoahHeap::verify(VerifyOption vo) {
1407 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1408 if (ShenandoahVerify) {
1409 verifier()->verify_generic(vo);
1410 } else {
1411 // TODO: Consider allocating verification bitmaps on demand,
1412 // and turn this on unconditionally.
1413 }
1414 }
1415 }
1416 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1417 return _free_set->capacity();
1418 }
1419
1420 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1421 private:
1422 MarkBitMap* _bitmap;
1423 Stack<oop,mtGC>* _oop_stack;
1424
1425 template <class T>
1426 void do_oop_work(T* p) {
1427 T o = RawAccess<>::oop_load(p);
1428 if (!CompressedOops::is_null(o)) {
1429 oop obj = CompressedOops::decode_not_null(o);
1430 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1431 assert(oopDesc::is_oop(obj), "must be a valid oop");
1432 if (!_bitmap->is_marked((HeapWord*) obj)) {
1433 _bitmap->mark((HeapWord*) obj);
1434 _oop_stack->push(obj);
1435 }
1436 }
1437 }
1438 public:
1439 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1440 _bitmap(bitmap), _oop_stack(oop_stack) {}
1441 void do_oop(oop* p) { do_oop_work(p); }
1442 void do_oop(narrowOop* p) { do_oop_work(p); }
1443 };
1444
1445 /*
1446 * This is public API, used in preparation of object_iterate().
1447 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1448 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1449 * control, we call SH::make_tlabs_parsable().
1450 */
1451 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1452 // No-op.
1453 }
1454
1455 /*
1456 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1457 *
1458 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1459 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1460 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1461 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1462 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1463 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1464 * wiped the bitmap in preparation for next marking).
1465 *
1466 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1467 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1468 * is allowed to report dead objects, but is not required to do so.
1469 */
1470 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1471 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1472 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1473 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1474 return;
1475 }
1476
1477 // Reset bitmap
1478 MemRegion mr = _aux_bit_map.covered();
1479 _aux_bit_map.clear_range_large(mr);
1480
1481 Stack<oop,mtGC> oop_stack;
1482
1483 // First, we process all GC roots. This populates the work stack with initial objects.
1484 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1485 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1486 CLDToOopClosure clds(&oops, false);
1487 CodeBlobToOopClosure blobs(&oops, false);
1488 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1489
1490 // Work through the oop stack to traverse heap.
1491 while (! oop_stack.is_empty()) {
1492 oop obj = oop_stack.pop();
1493 assert(oopDesc::is_oop(obj), "must be a valid oop");
1494 cl->do_object(obj);
1495 obj->oop_iterate(&oops);
1496 }
1497
1498 assert(oop_stack.is_empty(), "should be empty");
1499
1500 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1501 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1502 }
1503 }
1504
1505 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1506 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1507 object_iterate(cl);
1508 }
1509
1510 // Apply blk->heap_region_do() on all committed regions in address order,
1511 // terminating the iteration early if heap_region_do() returns true.
1512 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1513 for (size_t i = 0; i < num_regions(); i++) {
1514 ShenandoahHeapRegion* current = get_region(i);
1515 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1516 continue;
1517 }
1518 if (skip_cset_regions && in_collection_set(current)) {
1519 continue;
1520 }
1521 if (blk->heap_region_do(current)) {
1522 return;
1523 }
1524 }
1525 }
1526
1527 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1528 private:
1529 ShenandoahHeap* sh;
1530 public:
1531 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1532
1533 bool heap_region_do(ShenandoahHeapRegion* r) {
1534 r->clear_live_data();
1535 sh->next_marking_context()->set_top_at_mark_start(r->region_number(), r->top());
1536 return false;
1537 }
1538 };
1539
1540 void ShenandoahHeap::op_init_mark() {
1541 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1542
1543 assert(next_marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1544
1545 if (ShenandoahVerify) {
1546 verifier()->verify_before_concmark();
1547 }
1548
1549 {
1550 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1551 accumulate_statistics_tlabs();
1552 }
1553
1554 set_concurrent_mark_in_progress(true);
1555 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1556 {
1557 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1558 make_parsable(true);
1559 }
1560
1561 {
1562 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1563 ShenandoahClearLivenessClosure clc(this);
1564 heap_region_iterate(&clc);
1565 }
1566
1567 // Make above changes visible to worker threads
1568 OrderAccess::fence();
1569
1570 concurrentMark()->init_mark_roots();
1571
1572 if (UseTLAB) {
1573 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1574 resize_tlabs();
1575 }
1576
1577 if (ShenandoahPacing) {
1578 pacer()->setup_for_mark();
1579 }
1580 }
1581
1582 void ShenandoahHeap::op_mark() {
1583 concurrentMark()->mark_from_roots();
1584 }
1585
1586 void ShenandoahHeap::op_final_mark() {
1587 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1588
1589 // It is critical that we
1590 // evacuate roots right after finishing marking, so that we don't
1591 // get unmarked objects in the roots.
1592
1593 if (!cancelled_gc()) {
1594 concurrentMark()->finish_mark_from_roots();
1595 stop_concurrent_marking();
1596
1597 {
1598 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1599
1600 // All allocations past TAMS are implicitly live, adjust the region data.
1601 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1602 for (size_t i = 0; i < num_regions(); i++) {
1603 ShenandoahHeapRegion* r = get_region(i);
1604 if (!r->is_active()) continue;
1605
1606 HeapWord* tams = complete_marking_context()->top_at_mark_start(r->region_number());
1607 HeapWord* top = r->top();
1608 if (top > tams) {
1609 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1610 }
1611 }
1612 }
1613
1614 {
1615 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1616 prepare_for_concurrent_evacuation();
1617 }
1618
1619 // If collection set has candidates, start evacuation.
1620 // Otherwise, bypass the rest of the cycle.
1621 if (!collection_set()->is_empty()) {
1622 set_evacuation_in_progress(true);
1623 // From here on, we need to update references.
1624 set_has_forwarded_objects(true);
1625
1626 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1627 evacuate_and_update_roots();
1628 }
1629
1630 if (ShenandoahPacing) {
1631 pacer()->setup_for_evac();
1632 }
1633 } else {
1634 concurrentMark()->cancel();
1635 stop_concurrent_marking();
1636
1637 if (process_references()) {
1638 // Abandon reference processing right away: pre-cleaning must have failed.
1639 ReferenceProcessor *rp = ref_processor();
1640 rp->disable_discovery();
1641 rp->abandon_partial_discovery();
1642 rp->verify_no_references_recorded();
1643 }
1644 }
1645 }
1646
1647 void ShenandoahHeap::op_final_evac() {
1648 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1649
1650 set_evacuation_in_progress(false);
1651
1652 retire_and_reset_gclabs();
1653
1654 if (ShenandoahVerify) {
1655 verifier()->verify_after_evacuation();
1656 }
1657 }
1658
1659 void ShenandoahHeap::op_evac() {
1660 ShenandoahParallelEvacuationTask task(this, _collection_set);
1661 workers()->run_task(&task);
1662 }
1663
1664 void ShenandoahHeap::op_updaterefs() {
1665 update_heap_references(true);
1666 }
1667
1668 void ShenandoahHeap::op_cleanup() {
1669 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1670 free_set()->recycle_trash();
1671 }
1672
1673 void ShenandoahHeap::op_cleanup_bitmaps() {
1674 op_cleanup();
1675
1676 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1677 reset_next_mark_bitmap();
1678 }
1679
1680 void ShenandoahHeap::op_cleanup_traversal() {
1681 op_cleanup();
1682
1683 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1684 reset_next_mark_bitmap_traversal();
1685 }
1686
1687 void ShenandoahHeap::op_preclean() {
1688 concurrentMark()->preclean_weak_refs();
1689 }
1690
1691 void ShenandoahHeap::op_init_traversal() {
1692 traversal_gc()->init_traversal_collection();
1693 }
1694
1695 void ShenandoahHeap::op_traversal() {
1696 traversal_gc()->concurrent_traversal_collection();
1697 }
1698
1699 void ShenandoahHeap::op_final_traversal() {
1700 traversal_gc()->final_traversal_collection();
1701 }
1702
1703 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1704 ShenandoahMetricsSnapshot metrics;
1705 metrics.snap_before();
1706
1707 full_gc()->do_it(cause);
1708 if (UseTLAB) {
1709 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1710 resize_all_tlabs();
1711 }
1712
1713 metrics.snap_after();
1714 metrics.print();
1715
1716 if (metrics.is_good_progress("Full GC")) {
1717 _progress_last_gc.set();
1718 } else {
1719 // Nothing to do. Tell the allocation path that we have failed to make
1720 // progress, and it can finally fail.
1721 _progress_last_gc.unset();
1722 }
1723 }
1724
1725 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1726 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1727 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1728 // some phase, we have to upgrade the Degenerate GC to Full GC.
1729
1730 clear_cancelled_gc();
1731
1732 ShenandoahMetricsSnapshot metrics;
1733 metrics.snap_before();
1734
1735 switch (point) {
1736 case _degenerated_traversal:
1737 {
1738 // Drop the collection set. Note: this leaves some already forwarded objects
1739 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1740 // workarounds in ShenandoahTraversalHeuristics.
1741
1742 ShenandoahHeapLocker locker(lock());
1743 collection_set()->clear_current_index();
1744 for (size_t i = 0; i < collection_set()->count(); i++) {
1745 ShenandoahHeapRegion* r = collection_set()->next();
1746 r->make_regular_bypass();
1747 }
1748 collection_set()->clear();
1749 }
1750 op_final_traversal();
1751 op_cleanup_traversal();
1752 return;
1753
1754 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1755 // but enters it at different points, depending on which concurrent phase had
1756 // degenerated.
1757
1758 case _degenerated_outside_cycle:
1759 // We have degenerated from outside the cycle, which means something is bad with
1760 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1761 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1762 // we can do the most aggressive degen cycle, which includes processing references and
1763 // class unloading, unless those features are explicitly disabled.
1764 //
1765 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1766 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1767 set_process_references(ShenandoahRefProcFrequency != 0);
1768 set_unload_classes(ClassUnloading);
1769
1770 if (heuristics()->can_do_traversal_gc()) {
1771 // Not possible to degenerate from here, upgrade to Full GC right away.
1772 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1773 op_degenerated_fail();
1774 return;
1775 }
1776 op_init_mark();
1777 if (cancelled_gc()) {
1778 op_degenerated_fail();
1779 return;
1780 }
1781
1782 case _degenerated_mark:
1783 op_final_mark();
1784 if (cancelled_gc()) {
1785 op_degenerated_fail();
1786 return;
1787 }
1788
1789 op_cleanup();
1790
1791 case _degenerated_evac:
1792 // If heuristics thinks we should do the cycle, this flag would be set,
1793 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1794 if (is_evacuation_in_progress()) {
1795
1796 // Degeneration under oom-evac protocol might have left some objects in
1797 // collection set un-evacuated. Restart evacuation from the beginning to
1798 // capture all objects. For all the objects that are already evacuated,
1799 // it would be a simple check, which is supposed to be fast. This is also
1800 // safe to do even without degeneration, as CSet iterator is at beginning
1801 // in preparation for evacuation anyway.
1802 collection_set()->clear_current_index();
1803
1804 op_evac();
1805 if (cancelled_gc()) {
1806 op_degenerated_fail();
1807 return;
1808 }
1809 }
1810
1811 // If heuristics thinks we should do the cycle, this flag would be set,
1812 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1813 if (has_forwarded_objects()) {
1814 op_init_updaterefs();
1815 if (cancelled_gc()) {
1816 op_degenerated_fail();
1817 return;
1818 }
1819 }
1820
1821 case _degenerated_updaterefs:
1822 if (has_forwarded_objects()) {
1823 op_final_updaterefs();
1824 if (cancelled_gc()) {
1825 op_degenerated_fail();
1826 return;
1827 }
1828 }
1829
1830 op_cleanup_bitmaps();
1831 break;
1832
1833 default:
1834 ShouldNotReachHere();
1835 }
1836
1837 if (ShenandoahVerify) {
1838 verifier()->verify_after_degenerated();
1839 }
1840
1841 metrics.snap_after();
1842 metrics.print();
1843
1844 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1845 // because that probably means the heap is overloaded and/or fragmented.
1846 if (!metrics.is_good_progress("Degenerated GC")) {
1847 _progress_last_gc.unset();
1848 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1849 op_degenerated_futile();
1850 } else {
1851 _progress_last_gc.set();
1852 }
1853 }
1854
1855 void ShenandoahHeap::op_degenerated_fail() {
1856 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1857 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1858 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1859 }
1860
1861 void ShenandoahHeap::op_degenerated_futile() {
1862 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1863 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1864 }
1865
1866 void ShenandoahHeap::swap_mark_contexts() {
1867 ShenandoahMarkingContext* tmp = _complete_marking_context;
1868 _complete_marking_context = _next_marking_context;
1869 _next_marking_context = tmp;
1870 }
1871
1872
1873 void ShenandoahHeap::stop_concurrent_marking() {
1874 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1875 if (!cancelled_gc()) {
1876 // If we needed to update refs, and concurrent marking has been cancelled,
1877 // we need to finish updating references.
1878 set_has_forwarded_objects(false);
1879 swap_mark_contexts();
1880 }
1881 set_concurrent_mark_in_progress(false);
1882 }
1883
1884 void ShenandoahHeap::force_satb_flush_all_threads() {
1885 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1886 // No need to flush SATBs
1887 return;
1888 }
1889
1890 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1891 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1892 }
1893 // The threads are not "acquiring" their thread-local data, but it does not
1894 // hurt to "release" the updates here anyway.
1895 OrderAccess::fence();
1896 }
1897
1898 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1899 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1900 ShenandoahThreadLocalData::set_gc_state(t, state);
1901 }
1902 }
1903
1904 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1905 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1906 _gc_state.set_cond(mask, value);
1907 set_gc_state_all_threads(_gc_state.raw_value());
1908 }
1909
1910 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1911 set_gc_state_mask(MARKING, in_progress);
1912 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1913 }
1914
1915 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1916 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1917 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1918 }
1919
1920 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1921 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1922 set_gc_state_mask(EVACUATION, in_progress);
1923 }
1924
1925 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1926 // Initialize Brooks pointer for the next object
1927 HeapWord* result = obj + BrooksPointer::word_size();
1928 BrooksPointer::initialize(oop(result));
1929 return result;
1930 }
1931
1932 uint ShenandoahHeap::oop_extra_words() {
1933 return BrooksPointer::word_size();
1934 }
1935
1936 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1937 _mark_context(ShenandoahHeap::heap()->next_marking_context()) {
1938 }
1939
1940 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1941 _mark_context(ShenandoahHeap::heap()->next_marking_context()) {
1942 }
1943
1944 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1945 if (CompressedOops::is_null(obj)) {
1946 return false;
1947 }
1948 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1949 shenandoah_assert_not_forwarded_if(NULL, obj, ShenandoahHeap::heap()->is_concurrent_mark_in_progress() || ShenandoahHeap::heap()->is_concurrent_traversal_in_progress());
1950 return _mark_context->is_marked(obj);
1951 }
1952
1953 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1954 if (CompressedOops::is_null(obj)) {
1955 return false;
1956 }
1957 shenandoah_assert_not_forwarded(NULL, obj);
1958 return _mark_context->is_marked(obj);
1959 }
1960
1961 void ShenandoahHeap::ref_processing_init() {
1962 MemRegion mr = reserved_region();
1963
1964 assert(_max_workers > 0, "Sanity");
1965
1966 _ref_processor =
1967 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1968 true, // MT processing
1969 ParallelRefProcEnabled ? _max_workers : 1, // Degree of MT processing
1970 true, // MT discovery
1971 _max_workers, // Degree of MT discovery
1972 false, // Reference discovery is not atomic
1973 NULL, // No closure, should be installed before use
1974 true); // Scale worker threads
1975
1976 shenandoah_assert_rp_isalive_not_installed();
1977 }
1978
1979
1980 GCTracer* ShenandoahHeap::tracer() {
1981 return shenandoahPolicy()->tracer();
1982 }
1983
1984 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1985 return _free_set->used();
1986 }
1987
1988 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1989 if (try_cancel_gc()) {
1990 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1991 log_info(gc)("%s", msg.buffer());
1992 Events::log(Thread::current(), "%s", msg.buffer());
1993 }
1994 }
1995
1996 uint ShenandoahHeap::max_workers() {
1997 return _max_workers;
1998 }
1999
2000 void ShenandoahHeap::stop() {
2001 // The shutdown sequence should be able to terminate when GC is running.
2002
2003 // Step 0. Notify policy to disable event recording.
2004 _shenandoah_policy->record_shutdown();
2005
2006 // Step 1. Notify control thread that we are in shutdown.
2007 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2008 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2009 control_thread()->prepare_for_graceful_shutdown();
2010
2011 // Step 2. Notify GC workers that we are cancelling GC.
2012 cancel_gc(GCCause::_shenandoah_stop_vm);
2013
2014 // Step 3. Wait until GC worker exits normally.
2015 control_thread()->stop();
2016
2017 // Step 4. Stop String Dedup thread if it is active
2018 if (ShenandoahStringDedup::is_enabled()) {
2019 ShenandoahStringDedup::stop();
2020 }
2021 }
2022
2023 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
2024 assert(ClassUnloading || full_gc, "Class unloading should be enabled");
2025
2026 ShenandoahPhaseTimings::Phase phase_root =
2027 full_gc ?
2028 ShenandoahPhaseTimings::full_gc_purge :
2029 ShenandoahPhaseTimings::purge;
2030
2031 ShenandoahPhaseTimings::Phase phase_unload =
2032 full_gc ?
2033 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2034 ShenandoahPhaseTimings::purge_class_unload;
2035
2036 ShenandoahPhaseTimings::Phase phase_cldg =
2037 full_gc ?
2038 ShenandoahPhaseTimings::full_gc_purge_cldg :
2039 ShenandoahPhaseTimings::purge_cldg;
2040
2041 ShenandoahPhaseTimings::Phase phase_par =
2042 full_gc ?
2043 ShenandoahPhaseTimings::full_gc_purge_par :
2044 ShenandoahPhaseTimings::purge_par;
2045
2046 ShenandoahPhaseTimings::Phase phase_par_classes =
2047 full_gc ?
2048 ShenandoahPhaseTimings::full_gc_purge_par_classes :
2049 ShenandoahPhaseTimings::purge_par_classes;
2050
2051 ShenandoahPhaseTimings::Phase phase_par_codecache =
2052 full_gc ?
2053 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
2054 ShenandoahPhaseTimings::purge_par_codecache;
2055
2056 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2057 full_gc ?
2058 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2059 ShenandoahPhaseTimings::purge_par_symbstring;
2060
2061 ShenandoahPhaseTimings::Phase phase_par_sync =
2062 full_gc ?
2063 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2064 ShenandoahPhaseTimings::purge_par_sync;
2065
2066 ShenandoahGCPhase root_phase(phase_root);
2067
2068 ShenandoahIsAliveSelector alive;
2069 BoolObjectClosure* is_alive = alive.is_alive_closure();
2070
2071 bool purged_class;
2072
2073 // Unload classes and purge SystemDictionary.
2074 {
2075 ShenandoahGCPhase phase(phase_unload);
2076 purged_class = SystemDictionary::do_unloading(gc_timer(),
2077 full_gc /* do_cleaning*/ );
2078 }
2079
2080 {
2081 ShenandoahGCPhase phase(phase_par);
2082 uint active = _workers->active_workers();
2083 StringDedupUnlinkOrOopsDoClosure dedup_cl(is_alive, NULL);
2084 ParallelCleaningTask unlink_task(is_alive, &dedup_cl, active, purged_class);
2085 _workers->run_task(&unlink_task);
2086
2087 /*
2088 ShenandoahPhaseTimings* p = phase_timings();
2089 ParallelCleaningTimes times = unlink_task.times();
2090
2091 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2092 // by active workers to get average time per worker, that would add up to wall time.
2093 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2094 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2095 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2096 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2097 */
2098 }
2099
2100 if (ShenandoahStringDedup::is_enabled()) {
2101 ShenandoahPhaseTimings::Phase phase_purge_dedup =
2102 full_gc ?
2103 ShenandoahPhaseTimings::full_gc_purge_string_dedup :
2104 ShenandoahPhaseTimings::purge_string_dedup;
2105 ShenandoahGCPhase phase(phase_purge_dedup);
2106 ShenandoahStringDedup::parallel_cleanup();
2107 }
2108
2109 {
2110 ShenandoahGCPhase phase(phase_cldg);
2111 ClassLoaderDataGraph::purge();
2112 }
2113 }
2114
2115 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2116 set_gc_state_mask(HAS_FORWARDED, cond);
2117 }
2118
2119 bool ShenandoahHeap::last_gc_made_progress() const {
2120 return _progress_last_gc.is_set();
2121 }
2122
2123 void ShenandoahHeap::set_process_references(bool pr) {
2124 _process_references.set_cond(pr);
2125 }
2126
2127 void ShenandoahHeap::set_unload_classes(bool uc) {
2128 _unload_classes.set_cond(uc);
2129 }
2130
2131 bool ShenandoahHeap::process_references() const {
2132 return _process_references.is_set();
2133 }
2134
2135 bool ShenandoahHeap::unload_classes() const {
2136 return _unload_classes.is_set();
2137 }
2138
2139 //fixme this should be in heapregionset
2140 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2141 size_t region_idx = r->region_number() + 1;
2142 ShenandoahHeapRegion* next = get_region(region_idx);
2143 guarantee(next->region_number() == region_idx, "region number must match");
2144 while (next->is_humongous()) {
2145 region_idx = next->region_number() + 1;
2146 next = get_region(region_idx);
2147 guarantee(next->region_number() == region_idx, "region number must match");
2148 }
2149 return next;
2150 }
2151
2152 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2153 return _monitoring_support;
2154 }
2155
2156 address ShenandoahHeap::in_cset_fast_test_addr() {
2157 ShenandoahHeap* heap = ShenandoahHeap::heap();
2158 assert(heap->collection_set() != NULL, "Sanity");
2159 return (address) heap->collection_set()->biased_map_address();
2160 }
2161
2162 address ShenandoahHeap::cancelled_gc_addr() {
2163 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2164 }
2165
2166 address ShenandoahHeap::gc_state_addr() {
2167 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2168 }
2169
2170 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2171 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2172 }
2173
2174 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2175 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2176 }
2177
2178 ShenandoahPacer* ShenandoahHeap::pacer() const {
2179 assert (_pacer != NULL, "sanity");
2180 return _pacer;
2181 }
2182
2183 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2184 _degenerated_gc_in_progress.set_cond(in_progress);
2185 }
2186
2187 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2188 _full_gc_in_progress.set_cond(in_progress);
2189 }
2190
2191 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2192 assert (is_full_gc_in_progress(), "should be");
2193 _full_gc_move_in_progress.set_cond(in_progress);
2194 }
2195
2196 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2197 set_gc_state_mask(UPDATEREFS, in_progress);
2198 }
2199
2200 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2201 ShenandoahCodeRoots::add_nmethod(nm);
2202 }
2203
2204 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2205 ShenandoahCodeRoots::remove_nmethod(nm);
2206 }
2207
2208 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2209 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2210 ShenandoahHeapLocker locker(lock());
2211 heap_region_containing(o)->make_pinned();
2212 return o;
2213 }
2214
2215 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2216 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2217 ShenandoahHeapLocker locker(lock());
2218 heap_region_containing(o)->make_unpinned();
2219 }
2220
2221 GCTimer* ShenandoahHeap::gc_timer() const {
2222 return _gc_timer;
2223 }
2224
2225 #ifdef ASSERT
2226 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2227 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2228
2229 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2230 if (UseDynamicNumberOfGCThreads ||
2231 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2232 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2233 } else {
2234 // Use ParallelGCThreads inside safepoints
2235 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2236 }
2237 } else {
2238 if (UseDynamicNumberOfGCThreads ||
2239 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2240 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2241 } else {
2242 // Use ConcGCThreads outside safepoints
2243 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2244 }
2245 }
2246 }
2247 #endif
2248
2249 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2250 return _traversal_gc;
2251 }
2252
2253 ShenandoahVerifier* ShenandoahHeap::verifier() {
2254 guarantee(ShenandoahVerify, "Should be enabled");
2255 assert (_verifier != NULL, "sanity");
2256 return _verifier;
2257 }
2258
2259 template<class T>
2260 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2261 private:
2262 T cl;
2263 ShenandoahHeap* _heap;
2264 ShenandoahRegionIterator* _regions;
2265 bool _concurrent;
2266 public:
2267 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2268 AbstractGangTask("Concurrent Update References Task"),
2269 cl(T()),
2270 _heap(ShenandoahHeap::heap()),
2271 _regions(regions),
2272 _concurrent(concurrent) {
2273 }
2274
2275 void work(uint worker_id) {
2276 ShenandoahWorkerSession worker_session(worker_id);
2277 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2278 ShenandoahHeapRegion* r = _regions->next();
2279 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2280 while (r != NULL) {
2281 if (_heap->in_collection_set(r)) {
2282 HeapWord* bottom = r->bottom();
2283 HeapWord* top = ctx->top_at_mark_start(r->region_number());
2284 if (top > bottom) {
2285 ctx->clear_bitmap(bottom, top);
2286 }
2287 } else {
2288 if (r->is_active()) {
2289 _heap->marked_object_oop_safe_iterate(r, &cl);
2290 }
2291 }
2292 if (ShenandoahPacing) {
2293 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2294 assert (top_at_start_ur >= r->bottom(), "sanity");
2295 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2296 }
2297 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2298 return;
2299 }
2300 r = _regions->next();
2301 }
2302 }
2303 };
2304
2305 void ShenandoahHeap::update_heap_references(bool concurrent) {
2306 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2307 workers()->run_task(&task);
2308 }
2309
2310 void ShenandoahHeap::op_init_updaterefs() {
2311 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2312
2313 set_evacuation_in_progress(false);
2314
2315 retire_and_reset_gclabs();
2316
2317 if (ShenandoahVerify) {
2318 verifier()->verify_before_updaterefs();
2319 }
2320
2321 set_update_refs_in_progress(true);
2322 make_parsable(true);
2323 for (uint i = 0; i < num_regions(); i++) {
2324 ShenandoahHeapRegion* r = get_region(i);
2325 r->set_concurrent_iteration_safe_limit(r->top());
2326 }
2327
2328 // Reset iterator.
2329 _update_refs_iterator.reset();
2330
2331 if (ShenandoahPacing) {
2332 pacer()->setup_for_updaterefs();
2333 }
2334 }
2335
2336 void ShenandoahHeap::op_final_updaterefs() {
2337 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2338
2339 // Check if there is left-over work, and finish it
2340 if (_update_refs_iterator.has_next()) {
2341 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2342
2343 // Finish updating references where we left off.
2344 clear_cancelled_gc();
2345 update_heap_references(false);
2346 }
2347
2348 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2349 // everything. On degenerated paths, cancelled gc would not be set anyway.
2350 if (cancelled_gc()) {
2351 clear_cancelled_gc();
2352 }
2353 assert(!cancelled_gc(), "Should have been done right before");
2354
2355 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2356
2357 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2358
2359 trash_cset_regions();
2360 set_has_forwarded_objects(false);
2361 set_update_refs_in_progress(false);
2362
2363 if (ShenandoahVerify) {
2364 verifier()->verify_after_updaterefs();
2365 }
2366
2367 {
2368 ShenandoahHeapLocker locker(lock());
2369 _free_set->rebuild();
2370 }
2371 }
2372
2373 void ShenandoahHeap::set_alloc_seq_gc_start() {
2374 // Take next number, the start seq number is inclusive
2375 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2376 }
2377
2378 void ShenandoahHeap::set_alloc_seq_gc_end() {
2379 // Take current number, the end seq number is also inclusive
2380 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2381 }
2382
2383
2384 #ifdef ASSERT
2385 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2386 _lock.assert_owned_by_current_thread();
2387 }
2388
2389 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2390 _lock.assert_not_owned_by_current_thread();
2391 }
2392
2393 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2394 _lock.assert_owned_by_current_thread_or_safepoint();
2395 }
2396 #endif
2397
2398 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2399 print_on(st);
2400 print_heap_regions_on(st);
2401 }
2402
2403 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2404 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2405
2406 size_t regions_from = _bitmap_regions_per_slice * slice;
2407 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2408 for (size_t g = regions_from; g < regions_to; g++) {
2409 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2410 if (skip_self && g == r->region_number()) continue;
2411 if (get_region(g)->is_committed()) {
2412 return true;
2413 }
2414 }
2415 return false;
2416 }
2417
2418 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2419 assert_heaplock_owned_by_current_thread();
2420
2421 if (is_bitmap_slice_committed(r, true)) {
2422 // Some other region from the group is already committed, meaning the bitmap
2423 // slice is already committed, we exit right away.
2424 return true;
2425 }
2426
2427 // Commit the bitmap slice:
2428 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2429 size_t off = _bitmap_bytes_per_slice * slice;
2430 size_t len = _bitmap_bytes_per_slice;
2431 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2432 return false;
2433 }
2434 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2435 return false;
2436 }
2437 return true;
2438 }
2439
2440 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2441 assert_heaplock_owned_by_current_thread();
2442
2443 if (is_bitmap_slice_committed(r, true)) {
2444 // Some other region from the group is still committed, meaning the bitmap
2445 // slice is should stay committed, exit right away.
2446 return true;
2447 }
2448
2449 // Uncommit the bitmap slice:
2450 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2451 size_t off = _bitmap_bytes_per_slice * slice;
2452 size_t len = _bitmap_bytes_per_slice;
2453 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2454 return false;
2455 }
2456 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2457 return false;
2458 }
2459 return true;
2460 }
2461
2462 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2463 assert_heaplock_owned_by_current_thread();
2464 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2465
2466 if (is_bitmap_slice_committed(r, true)) {
2467 // Some other region from the group is still committed, meaning the bitmap
2468 // slice is should stay committed, exit right away.
2469 return true;
2470 }
2471
2472 // Idle the bitmap slice:
2473 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2474 size_t off = _bitmap_bytes_per_slice * slice;
2475 size_t len = _bitmap_bytes_per_slice;
2476 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2477 return false;
2478 }
2479 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2480 return false;
2481 }
2482 return true;
2483 }
2484
2485 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2486 assert_heaplock_owned_by_current_thread();
2487 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2488 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2489 size_t off = _bitmap_bytes_per_slice * slice;
2490 size_t len = _bitmap_bytes_per_slice;
2491 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2492 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2493 }
2494
2495 void ShenandoahHeap::safepoint_synchronize_begin() {
2496 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2497 SuspendibleThreadSet::synchronize();
2498 }
2499 }
2500
2501 void ShenandoahHeap::safepoint_synchronize_end() {
2502 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2503 SuspendibleThreadSet::desynchronize();
2504 }
2505 }
2506
2507 void ShenandoahHeap::vmop_entry_init_mark() {
2508 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2509 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2510 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2511
2512 try_inject_alloc_failure();
2513 VM_ShenandoahInitMark op;
2514 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2515 }
2516
2517 void ShenandoahHeap::vmop_entry_final_mark() {
2518 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2519 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2520 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2521
2522 try_inject_alloc_failure();
2523 VM_ShenandoahFinalMarkStartEvac op;
2524 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2525 }
2526
2527 void ShenandoahHeap::vmop_entry_final_evac() {
2528 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2529 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2530 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2531
2532 VM_ShenandoahFinalEvac op;
2533 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2534 }
2535
2536 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2537 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2538 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2539 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2540
2541 try_inject_alloc_failure();
2542 VM_ShenandoahInitUpdateRefs op;
2543 VMThread::execute(&op);
2544 }
2545
2546 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2547 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2548 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2549 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2550
2551 try_inject_alloc_failure();
2552 VM_ShenandoahFinalUpdateRefs op;
2553 VMThread::execute(&op);
2554 }
2555
2556 void ShenandoahHeap::vmop_entry_init_traversal() {
2557 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2558 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2559 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2560
2561 try_inject_alloc_failure();
2562 VM_ShenandoahInitTraversalGC op;
2563 VMThread::execute(&op);
2564 }
2565
2566 void ShenandoahHeap::vmop_entry_final_traversal() {
2567 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2568 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2569 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2570
2571 try_inject_alloc_failure();
2572 VM_ShenandoahFinalTraversalGC op;
2573 VMThread::execute(&op);
2574 }
2575
2576 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2577 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2578 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2579 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2580
2581 try_inject_alloc_failure();
2582 VM_ShenandoahFullGC op(cause);
2583 VMThread::execute(&op);
2584 }
2585
2586 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2587 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2588 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2589 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2590
2591 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2592 VMThread::execute(°enerated_gc);
2593 }
2594
2595 void ShenandoahHeap::entry_init_mark() {
2596 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2597 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2598 const char* msg = init_mark_event_message();
2599 GCTraceTime(Info, gc) time(msg, gc_timer());
2600 EventMark em("%s", msg);
2601
2602 ShenandoahWorkerScope scope(workers(),
2603 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2604 "init marking");
2605
2606 op_init_mark();
2607 }
2608
2609 void ShenandoahHeap::entry_final_mark() {
2610 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2611 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2612 const char* msg = final_mark_event_message();
2613 GCTraceTime(Info, gc) time(msg, gc_timer());
2614 EventMark em("%s", msg);
2615
2616 ShenandoahWorkerScope scope(workers(),
2617 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2618 "final marking");
2619
2620 op_final_mark();
2621 }
2622
2623 void ShenandoahHeap::entry_final_evac() {
2624 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2625 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2626 static const char* msg = "Pause Final Evac";
2627 GCTraceTime(Info, gc) time(msg, gc_timer());
2628 EventMark em("%s", msg);
2629
2630 op_final_evac();
2631 }
2632
2633 void ShenandoahHeap::entry_init_updaterefs() {
2634 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2635 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2636
2637 static const char* msg = "Pause Init Update Refs";
2638 GCTraceTime(Info, gc) time(msg, gc_timer());
2639 EventMark em("%s", msg);
2640
2641 // No workers used in this phase, no setup required
2642
2643 op_init_updaterefs();
2644 }
2645
2646 void ShenandoahHeap::entry_final_updaterefs() {
2647 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2648 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2649
2650 static const char* msg = "Pause Final Update Refs";
2651 GCTraceTime(Info, gc) time(msg, gc_timer());
2652 EventMark em("%s", msg);
2653
2654 ShenandoahWorkerScope scope(workers(),
2655 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2656 "final reference update");
2657
2658 op_final_updaterefs();
2659 }
2660
2661 void ShenandoahHeap::entry_init_traversal() {
2662 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2663 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2664
2665 static const char* msg = "Pause Init Traversal";
2666 GCTraceTime(Info, gc) time(msg, gc_timer());
2667 EventMark em("%s", msg);
2668
2669 ShenandoahWorkerScope scope(workers(),
2670 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2671 "init traversal");
2672
2673 op_init_traversal();
2674 }
2675
2676 void ShenandoahHeap::entry_final_traversal() {
2677 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2678 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2679
2680 static const char* msg = "Pause Final Traversal";
2681 GCTraceTime(Info, gc) time(msg, gc_timer());
2682 EventMark em("%s", msg);
2683
2684 ShenandoahWorkerScope scope(workers(),
2685 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2686 "final traversal");
2687
2688 op_final_traversal();
2689 }
2690
2691 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2692 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2693 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2694
2695 static const char* msg = "Pause Full";
2696 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2697 EventMark em("%s", msg);
2698
2699 ShenandoahWorkerScope scope(workers(),
2700 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2701 "full gc");
2702
2703 op_full(cause);
2704 }
2705
2706 void ShenandoahHeap::entry_degenerated(int point) {
2707 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2708 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2709
2710 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2711 const char* msg = degen_event_message(dpoint);
2712 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2713 EventMark em("%s", msg);
2714
2715 ShenandoahWorkerScope scope(workers(),
2716 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2717 "stw degenerated gc");
2718
2719 set_degenerated_gc_in_progress(true);
2720 op_degenerated(dpoint);
2721 set_degenerated_gc_in_progress(false);
2722 }
2723
2724 void ShenandoahHeap::entry_mark() {
2725 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2726
2727 const char* msg = conc_mark_event_message();
2728 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2729 EventMark em("%s", msg);
2730
2731 ShenandoahWorkerScope scope(workers(),
2732 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2733 "concurrent marking");
2734
2735 try_inject_alloc_failure();
2736 op_mark();
2737 }
2738
2739 void ShenandoahHeap::entry_evac() {
2740 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2741 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2742
2743 static const char* msg = "Concurrent evacuation";
2744 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2745 EventMark em("%s", msg);
2746
2747 ShenandoahWorkerScope scope(workers(),
2748 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2749 "concurrent evacuation");
2750
2751 try_inject_alloc_failure();
2752 op_evac();
2753 }
2754
2755 void ShenandoahHeap::entry_updaterefs() {
2756 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2757
2758 static const char* msg = "Concurrent update references";
2759 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2760 EventMark em("%s", msg);
2761
2762 ShenandoahWorkerScope scope(workers(),
2763 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2764 "concurrent reference update");
2765
2766 try_inject_alloc_failure();
2767 op_updaterefs();
2768 }
2769 void ShenandoahHeap::entry_cleanup() {
2770 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2771
2772 static const char* msg = "Concurrent cleanup";
2773 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2774 EventMark em("%s", msg);
2775
2776 // This phase does not use workers, no need for setup
2777
2778 try_inject_alloc_failure();
2779 op_cleanup();
2780 }
2781
2782 void ShenandoahHeap::entry_cleanup_traversal() {
2783 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2784
2785 static const char* msg = "Concurrent cleanup";
2786 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2787 EventMark em("%s", msg);
2788
2789 ShenandoahWorkerScope scope(workers(),
2790 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2791 "concurrent traversal cleanup");
2792
2793 try_inject_alloc_failure();
2794 op_cleanup_traversal();
2795 }
2796
2797 void ShenandoahHeap::entry_cleanup_bitmaps() {
2798 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2799
2800 static const char* msg = "Concurrent cleanup";
2801 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2802 EventMark em("%s", msg);
2803
2804 ShenandoahWorkerScope scope(workers(),
2805 ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup(),
2806 "concurrent cleanup");
2807
2808 try_inject_alloc_failure();
2809 op_cleanup_bitmaps();
2810 }
2811
2812 void ShenandoahHeap::entry_preclean() {
2813 if (ShenandoahPreclean && process_references()) {
2814 static const char* msg = "Concurrent precleaning";
2815 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2816 EventMark em("%s", msg);
2817
2818 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2819
2820 ShenandoahWorkerScope scope(workers(),
2821 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2822 "concurrent preclean");
2823
2824 try_inject_alloc_failure();
2825 op_preclean();
2826 }
2827 }
2828
2829 void ShenandoahHeap::entry_traversal() {
2830 static const char* msg = "Concurrent traversal";
2831 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2832 EventMark em("%s", msg);
2833
2834 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2835
2836 ShenandoahWorkerScope scope(workers(),
2837 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2838 "concurrent traversal");
2839
2840 try_inject_alloc_failure();
2841 op_traversal();
2842 }
2843
2844 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2845 static const char *msg = "Concurrent uncommit";
2846 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2847 EventMark em("%s", msg);
2848
2849 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2850
2851 op_uncommit(shrink_before);
2852 }
2853
2854 void ShenandoahHeap::try_inject_alloc_failure() {
2855 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2856 _inject_alloc_failure.set();
2857 os::naked_short_sleep(1);
2858 if (cancelled_gc()) {
2859 log_info(gc)("Allocation failure was successfully injected");
2860 }
2861 }
2862 }
2863
2864 bool ShenandoahHeap::should_inject_alloc_failure() {
2865 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2866 }
2867
2868 void ShenandoahHeap::initialize_serviceability() {
2869 _memory_pool = new ShenandoahMemoryPool(this);
2870 _cycle_memory_manager.add_pool(_memory_pool);
2871 _stw_memory_manager.add_pool(_memory_pool);
2872 }
2873
2874 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2875 GrowableArray<GCMemoryManager*> memory_managers(2);
2876 memory_managers.append(&_cycle_memory_manager);
2877 memory_managers.append(&_stw_memory_manager);
2878 return memory_managers;
2879 }
2880
2881 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2882 GrowableArray<MemoryPool*> memory_pools(1);
2883 memory_pools.append(_memory_pool);
2884 return memory_pools;
2885 }
2886
2887 void ShenandoahHeap::enter_evacuation() {
2888 _oom_evac_handler.enter_evacuation();
2889 }
2890
2891 void ShenandoahHeap::leave_evacuation() {
2892 _oom_evac_handler.leave_evacuation();
2893 }
2894
2895 SoftRefPolicy* ShenandoahHeap::soft_ref_policy() {
2896 return &_soft_ref_policy;
2897 }
2898
2899 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2900 _index(0),
2901 _heap(ShenandoahHeap::heap()) {}
2902
2903 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2904 _index(0),
2905 _heap(heap) {}
2906
2907 void ShenandoahRegionIterator::reset() {
2908 _index = 0;
2909 }
2910
2911 bool ShenandoahRegionIterator::has_next() const {
2912 return _index < _heap->num_regions();
2913 }
2914
2915 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
2916 ShenandoahRegionIterator regions;
2917 ShenandoahHeapRegion* r = regions.next();
2918 while (r != NULL) {
2919 if (cl.heap_region_do(r)) {
2920 break;
2921 }
2922 r = regions.next();
2923 }
2924 }
2925
2926 char ShenandoahHeap::gc_state() const {
2927 return _gc_state.raw_value();
2928 }
2929
2930 void ShenandoahHeap::deduplicate_string(oop str) {
2931 assert(java_lang_String::is_instance(str), "invariant");
2932
2933 if (ShenandoahStringDedup::is_enabled()) {
2934 ShenandoahStringDedup::deduplicate(str);
2935 }
2936 }
2937
2938 const char* ShenandoahHeap::init_mark_event_message() const {
2939 bool update_refs = has_forwarded_objects();
2940 bool proc_refs = process_references();
2941 bool unload_cls = unload_classes();
2942
2943 if (update_refs && proc_refs && unload_cls) {
2944 return "Pause Init Mark (update refs) (process refs) (unload classes)";
2945 } else if (update_refs && proc_refs) {
2946 return "Pause Init Mark (update refs) (process refs)";
2947 } else if (update_refs && unload_cls) {
2948 return "Pause Init Mark (update refs) (unload classes)";
2949 } else if (proc_refs && unload_cls) {
2950 return "Pause Init Mark (process refs) (unload classes)";
2951 } else if (update_refs) {
2952 return "Pause Init Mark (update refs)";
2953 } else if (proc_refs) {
2954 return "Pause Init Mark (process refs)";
2955 } else if (unload_cls) {
2956 return "Pause Init Mark (unload classes)";
2957 } else {
2958 return "Pause Init Mark";
2959 }
2960 }
2961
2962 const char* ShenandoahHeap::final_mark_event_message() const {
2963 bool update_refs = has_forwarded_objects();
2964 bool proc_refs = process_references();
2965 bool unload_cls = unload_classes();
2966
2967 if (update_refs && proc_refs && unload_cls) {
2968 return "Pause Final Mark (update refs) (process refs) (unload classes)";
2969 } else if (update_refs && proc_refs) {
2970 return "Pause Final Mark (update refs) (process refs)";
2971 } else if (update_refs && unload_cls) {
2972 return "Pause Final Mark (update refs) (unload classes)";
2973 } else if (proc_refs && unload_cls) {
2974 return "Pause Final Mark (process refs) (unload classes)";
2975 } else if (update_refs) {
2976 return "Pause Final Mark (update refs)";
2977 } else if (proc_refs) {
2978 return "Pause Final Mark (process refs)";
2979 } else if (unload_cls) {
2980 return "Pause Final Mark (unload classes)";
2981 } else {
2982 return "Pause Final Mark";
2983 }
2984 }
2985
2986 const char* ShenandoahHeap::conc_mark_event_message() const {
2987 bool update_refs = has_forwarded_objects();
2988 bool proc_refs = process_references();
2989 bool unload_cls = unload_classes();
2990
2991 if (update_refs && proc_refs && unload_cls) {
2992 return "Concurrent marking (update refs) (process refs) (unload classes)";
2993 } else if (update_refs && proc_refs) {
2994 return "Concurrent marking (update refs) (process refs)";
2995 } else if (update_refs && unload_cls) {
2996 return "Concurrent marking (update refs) (unload classes)";
2997 } else if (proc_refs && unload_cls) {
2998 return "Concurrent marking (process refs) (unload classes)";
2999 } else if (update_refs) {
3000 return "Concurrent marking (update refs)";
3001 } else if (proc_refs) {
3002 return "Concurrent marking (process refs)";
3003 } else if (unload_cls) {
3004 return "Concurrent marking (unload classes)";
3005 } else {
3006 return "Concurrent marking";
3007 }
3008 }
3009
3010 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
3011 switch (point) {
3012 case _degenerated_unset:
3013 return "Pause Degenerated GC (<UNSET>)";
3014 case _degenerated_traversal:
3015 return "Pause Degenerated GC (Traversal)";
3016 case _degenerated_outside_cycle:
3017 return "Pause Degenerated GC (Outside of Cycle)";
3018 case _degenerated_mark:
3019 return "Pause Degenerated GC (Mark)";
3020 case _degenerated_evac:
3021 return "Pause Degenerated GC (Evacuation)";
3022 case _degenerated_updaterefs:
3023 return "Pause Degenerated GC (Update Refs)";
3024 default:
3025 ShouldNotReachHere();
3026 return "ERROR";
3027 }
3028 }
3029
3030
3031 BoolObjectClosure* ShenandoahIsAliveSelector::is_alive_closure() {
3032 return ShenandoahHeap::heap()->has_forwarded_objects() ? reinterpret_cast<BoolObjectClosure*>(&_fwd_alive_cl)
3033 : reinterpret_cast<BoolObjectClosure*>(&_alive_cl);
3034 }