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/shenandoahMemoryPool.hpp"
48 #include "gc/shenandoah/shenandoahMetrics.hpp"
49 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
50 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
51 #include "gc/shenandoah/shenandoahPacer.hpp"
52 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
53 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
54 #include "gc/shenandoah/shenandoahStringDedup.hpp"
55 #include "gc/shenandoah/shenandoahUtils.hpp"
56 #include "gc/shenandoah/shenandoahVerifier.hpp"
57 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
58 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
59 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPartialConnectedHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahPartialGenerationalHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahPartialLRUHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
67 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
68
69 #include "memory/metaspace.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/mallocTracker.hpp"
72
73 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
74
75 #ifdef ASSERT
76 template <class T>
77 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
78 T o = RawAccess<>::oop_load(p);
79 if (! CompressedOops::is_null(o)) {
80 oop obj = CompressedOops::decode_not_null(o);
81 shenandoah_assert_not_forwarded(p, obj);
82 }
83 }
84
85 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
86 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
87 #endif
88
89 const char* ShenandoahHeap::name() const {
90 return "Shenandoah";
91 }
92
93 class ShenandoahPretouchTask : public AbstractGangTask {
94 private:
95 ShenandoahRegionIterator _regions;
96 const size_t _bitmap_size;
97 const size_t _page_size;
98 char* _bitmap0_base;
99 char* _bitmap1_base;
100 public:
101 ShenandoahPretouchTask(char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
102 size_t page_size) :
103 AbstractGangTask("Shenandoah PreTouch"),
104 _bitmap0_base(bitmap0_base),
105 _bitmap1_base(bitmap1_base),
106 _bitmap_size(bitmap_size),
107 _page_size(page_size) {}
108
109 virtual void work(uint worker_id) {
110 ShenandoahHeapRegion* r = _regions.next();
111 while (r != NULL) {
112 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
113 r->region_number(), p2i(r->bottom()), p2i(r->end()));
114 os::pretouch_memory(r->bottom(), r->end(), _page_size);
115
116 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
117 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
118 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
119
120 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
121 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
122 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
123
124 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
125 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
126 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
127
128 r = _regions.next();
129 }
130 }
131 };
132
133 jint ShenandoahHeap::initialize() {
134
135 BrooksPointer::initial_checks();
136
137 initialize_heuristics();
138
139 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
140 size_t max_byte_size = collector_policy()->max_heap_byte_size();
141 size_t heap_alignment = collector_policy()->heap_alignment();
142
143 if (ShenandoahAlwaysPreTouch) {
144 // Enabled pre-touch means the entire heap is committed right away.
145 init_byte_size = max_byte_size;
146 }
147
148 Universe::check_alignment(max_byte_size,
149 ShenandoahHeapRegion::region_size_bytes(),
150 "shenandoah heap");
151 Universe::check_alignment(init_byte_size,
152 ShenandoahHeapRegion::region_size_bytes(),
153 "shenandoah heap");
154
155 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
156 heap_alignment);
157 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
158
159 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
160 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
161
162 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
163 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
164 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
165 _committed = _initial_size;
166
167 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
168 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
169 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
170 }
171
172 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
173 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
174
175 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
176 _free_set = new ShenandoahFreeSet(this, _num_regions);
177
178 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
179
180 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
181 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
182 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
183
184 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
185 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
186 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
187
188 if (ShenandoahPacing) {
189 _pacer = new ShenandoahPacer(this);
190 _pacer->setup_for_idle();
191 } else {
192 _pacer = NULL;
193 }
194
195 {
196 ShenandoahHeapLocker locker(lock());
197 for (size_t i = 0; i < _num_regions; i++) {
198 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
199 (HeapWord*) pgc_rs.base() + reg_size_words * i,
200 reg_size_words,
201 i,
202 i < num_committed_regions);
203
204 _complete_top_at_mark_starts_base[i] = r->bottom();
205 _next_top_at_mark_starts_base[i] = r->bottom();
206 _regions[i] = r;
207 assert(!collection_set()->is_in(i), "New region should not be in collection set");
208 }
209
210 _free_set->rebuild();
211 }
212
213 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
214 "misaligned heap: "PTR_FORMAT, p2i(base()));
215
216 // The call below uses stuff (the SATB* things) that are in G1, but probably
217 // belong into a shared location.
218 ShenandoahBarrierSet::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
219 SATB_Q_FL_lock,
220 20 /*G1SATBProcessCompletedThreshold */,
221 Shared_SATB_Q_lock);
222
223 // Reserve space for prev and next bitmap.
224 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
225 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
226 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
227 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
228
229 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
230
231 guarantee(bitmap_bytes_per_region != 0,
232 "Bitmap bytes per region should not be zero");
233 guarantee(is_power_of_2(bitmap_bytes_per_region),
234 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
235
236 if (bitmap_page_size > bitmap_bytes_per_region) {
237 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
238 _bitmap_bytes_per_slice = bitmap_page_size;
239 } else {
240 _bitmap_regions_per_slice = 1;
241 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
242 }
243
244 guarantee(_bitmap_regions_per_slice >= 1,
245 "Should have at least one region per slice: " SIZE_FORMAT,
246 _bitmap_regions_per_slice);
247
248 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
249 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
250 _bitmap_bytes_per_slice, bitmap_page_size);
251
252 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
253 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
254 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
255
256 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
257 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
258 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
259
260 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
261 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
262 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
263 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
264 "couldn't allocate initial bitmap");
265 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
266 "couldn't allocate initial bitmap");
267
268 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
269
270 if (ShenandoahVerify) {
271 ReservedSpace verify_bitmap(_bitmap_size, page_size);
272 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
273 "couldn't allocate verification bitmap");
274 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
275 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
276 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
277 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
278 }
279
280 if (ShenandoahAlwaysPreTouch) {
281 assert (!AlwaysPreTouch, "Should have been overridden");
282
283 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
284 // before initialize() below zeroes it with initializing thread. For any given region,
285 // we touch the region and the corresponding bitmaps from the same thread.
286 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
287
288 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
289 _num_regions, page_size);
290 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
291 _workers->run_task(&cl);
292 }
293
294 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
295 _complete_mark_bit_map = &_mark_bit_map0;
296
297 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
298 _next_mark_bit_map = &_mark_bit_map1;
299
300 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
301 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
302 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
303 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
304 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
305
306 if (UseShenandoahMatrix) {
307 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
308 } else {
309 _connection_matrix = NULL;
310 }
311
312 _traversal_gc = heuristics()->can_do_traversal_gc() ?
313 new ShenandoahTraversalGC(this, _num_regions) :
314 NULL;
315
316 _monitoring_support = new ShenandoahMonitoringSupport(this);
317
318 _phase_timings = new ShenandoahPhaseTimings();
319
320 if (ShenandoahAllocationTrace) {
321 _alloc_tracker = new ShenandoahAllocTracker();
322 }
323
324 ShenandoahStringDedup::initialize();
325
326 _control_thread = new ShenandoahControlThread();
327
328 ShenandoahCodeRoots::initialize();
329
330 LogTarget(Trace, gc, region) lt;
331 if (lt.is_enabled()) {
332 ResourceMark rm;
333 LogStream ls(lt);
334 log_trace(gc, region)("All Regions");
335 print_heap_regions_on(&ls);
336 log_trace(gc, region)("Free Regions");
337 _free_set->print_on(&ls);
338 }
339
340 log_info(gc, init)("Safepointing mechanism: %s",
341 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
342 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
343
344 return JNI_OK;
345 }
346
347 void ShenandoahHeap::initialize_heuristics() {
348 if (ShenandoahGCHeuristics != NULL) {
349 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
350 _heuristics = new ShenandoahAggressiveHeuristics();
351 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
352 _heuristics = new ShenandoahStaticHeuristics();
353 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
354 _heuristics = new ShenandoahAdaptiveHeuristics();
355 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
356 _heuristics = new ShenandoahPassiveHeuristics();
357 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
358 _heuristics = new ShenandoahCompactHeuristics();
359 } else if (strcmp(ShenandoahGCHeuristics, "connected") == 0) {
360 _heuristics = new ShenandoahPartialConnectedHeuristics();
361 } else if (strcmp(ShenandoahGCHeuristics, "generational") == 0) {
362 _heuristics = new ShenandoahPartialGenerationalHeuristics();
363 } else if (strcmp(ShenandoahGCHeuristics, "LRU") == 0) {
364 _heuristics = new ShenandoahPartialLRUHeuristics();
365 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
366 _heuristics = new ShenandoahTraversalHeuristics();
367 } else {
368 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
369 }
370
371 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
372 vm_exit_during_initialization(
373 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
374 _heuristics->name()));
375 }
376 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
377 vm_exit_during_initialization(
378 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
379 _heuristics->name()));
380 }
381
382 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
383 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
384 }
385 log_info(gc, init)("Shenandoah heuristics: %s",
386 _heuristics->name());
387 _heuristics->print_thresholds();
388 } else {
389 ShouldNotReachHere();
390 }
391
392 }
393
394 #ifdef _MSC_VER
395 #pragma warning( push )
396 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
397 #endif
398
399 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
400 CollectedHeap(),
401 _shenandoah_policy(policy),
402 _soft_ref_policy(),
403 _regions(NULL),
404 _free_set(NULL),
405 _collection_set(NULL),
406 _update_refs_iterator(this),
407 _bytes_allocated_since_gc_start(0),
408 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
409 _ref_processor(NULL),
410 _next_top_at_mark_starts(NULL),
411 _next_top_at_mark_starts_base(NULL),
412 _complete_top_at_mark_starts(NULL),
413 _complete_top_at_mark_starts_base(NULL),
414 _mark_bit_map0(),
415 _mark_bit_map1(),
416 _aux_bit_map(),
417 _connection_matrix(NULL),
418 _verifier(NULL),
419 _pacer(NULL),
420 _used_at_last_gc(0),
421 _alloc_seq_at_last_gc_start(0),
422 _alloc_seq_at_last_gc_end(0),
423 _safepoint_workers(NULL),
424 _gc_cycle_mode(),
425 #ifdef ASSERT
426 _heap_expansion_count(0),
427 #endif
428 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
429 _phase_timings(NULL),
430 _alloc_tracker(NULL),
431 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
432 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
433 _memory_pool(NULL)
434 {
435 log_info(gc, init)("Parallel GC threads: " UINT32_FORMAT, ParallelGCThreads);
436 log_info(gc, init)("Concurrent GC threads: " UINT32_FORMAT, ConcGCThreads);
437 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
438
439 _scm = new ShenandoahConcurrentMark();
440 _full_gc = new ShenandoahMarkCompact();
441 _used = 0;
442
443 _max_workers = MAX2(_max_workers, 1U);
444 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
445 /* are_GC_task_threads */true,
446 /* are_ConcurrentGC_threads */false);
447 if (_workers == NULL) {
448 vm_exit_during_initialization("Failed necessary allocation.");
449 } else {
450 _workers->initialize_workers();
451 }
452
453 if (ParallelSafepointCleanupThreads > 1) {
454 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
455 ParallelSafepointCleanupThreads,
456 false, false);
457 _safepoint_workers->initialize_workers();
458 }
459 }
460
461 #ifdef _MSC_VER
462 #pragma warning( pop )
463 #endif
464
465 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
466 private:
467 ShenandoahRegionIterator _regions;
468
469 public:
470 ShenandoahResetNextBitmapTask() :
471 AbstractGangTask("Parallel Reset Bitmap Task") {}
472
473 void work(uint worker_id) {
474 ShenandoahHeapRegion* region = _regions.next();
475 ShenandoahHeap* heap = ShenandoahHeap::heap();
476 while (region != NULL) {
477 if (heap->is_bitmap_slice_committed(region)) {
478 HeapWord* bottom = region->bottom();
479 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
480 if (top > bottom) {
481 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
482 }
483 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
484 }
485 region = _regions.next();
486 }
487 }
488 };
489
490 void ShenandoahHeap::reset_next_mark_bitmap() {
491 assert_gc_workers(_workers->active_workers());
492
493 ShenandoahResetNextBitmapTask task;
494 _workers->run_task(&task);
495 }
496
497 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
498 private:
499 ShenandoahHeapRegionSetIterator& _regions;
500
501 public:
502 ShenandoahResetNextBitmapTraversalTask(ShenandoahHeapRegionSetIterator& regions) :
503 AbstractGangTask("Parallel Reset Bitmap Task for Traversal"),
504 _regions(regions) {}
505
506 void work(uint worker_id) {
507 ShenandoahHeap* heap = ShenandoahHeap::heap();
508 ShenandoahHeapRegion* region = _regions.claim_next();
509 while (region != NULL) {
510 if (!region->is_trash()) {
511 assert(!region->is_empty_uncommitted(), "sanity");
512 assert(heap->is_bitmap_slice_committed(region), "sanity");
513 HeapWord* bottom = region->bottom();
514 HeapWord* top = heap->next_top_at_mark_start(bottom);
515 assert(top <= region->top(),
516 "TAMS must smaller/equals than top: TAMS: "PTR_FORMAT", top: "PTR_FORMAT,
517 p2i(top), p2i(region->top()));
518 if (top > bottom) {
519 heap->complete_mark_bit_map()->copy_from(heap->next_mark_bit_map(), MemRegion(bottom, top));
520 heap->set_complete_top_at_mark_start(bottom, top);
521 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
522 heap->set_next_top_at_mark_start(bottom, bottom);
523 }
524 assert(heap->is_next_bitmap_clear_range(region->bottom(), region->end()),
525 "need clear next bitmap");
526 }
527 region = _regions.claim_next();
528 }
529 }
530 };
531
532 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
533 assert_gc_workers(_workers->active_workers());
534
535 ShenandoahHeapRegionSet* regions = traversal_gc()->traversal_set();
536 ShenandoahHeapRegionSetIterator iter(regions);
537 ShenandoahResetNextBitmapTraversalTask task(iter);
538 _workers->run_task(&task);
539 }
540
541 bool ShenandoahHeap::is_next_bitmap_clear() {
542 for (size_t idx = 0; idx < _num_regions; idx++) {
543 ShenandoahHeapRegion* r = get_region(idx);
544 if (is_bitmap_slice_committed(r) && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
545 return false;
546 }
547 }
548 return true;
549 }
550
551 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
552 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
553 }
554
555 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
556 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
557 }
558
559 void ShenandoahHeap::print_on(outputStream* st) const {
560 st->print_cr("Shenandoah Heap");
561 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
562 capacity() / K, committed() / K, used() / K);
563 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
564 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
565
566 st->print("Status: ");
567 if (has_forwarded_objects()) st->print("has forwarded objects, ");
568 if (is_concurrent_mark_in_progress()) st->print("marking, ");
569 if (is_evacuation_in_progress()) st->print("evacuating, ");
570 if (is_update_refs_in_progress()) st->print("updating refs, ");
571 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
572 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
573 if (is_full_gc_in_progress()) st->print("full gc, ");
574 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
575
576 if (cancelled_gc()) {
577 st->print("cancelled");
578 } else {
579 st->print("not cancelled");
580 }
581 st->cr();
582
583 st->print_cr("Reserved region:");
584 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
585 p2i(reserved_region().start()),
586 p2i(reserved_region().end()));
587
588 st->cr();
589 MetaspaceUtils::print_on(st);
590
591 if (UseShenandoahMatrix) {
592 st->print_cr("Matrix:");
593
594 ShenandoahConnectionMatrix* matrix = connection_matrix();
595 if (matrix != NULL) {
596 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
597 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
598 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
599 } else {
600 st->print_cr(" No matrix.");
601 }
602 }
603
604 if (Verbose) {
605 print_heap_regions_on(st);
606 }
607 }
608
609 class ShenandoahInitGCLABClosure : public ThreadClosure {
610 public:
611 void do_thread(Thread* thread) {
612 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread() ||
613 thread->is_ConcurrentGC_thread())) {
614 ShenandoahThreadLocalData::initialize_gclab(thread);
615 }
616 }
617 };
618
619 void ShenandoahHeap::post_initialize() {
620 CollectedHeap::post_initialize();
621 MutexLocker ml(Threads_lock);
622
623 ShenandoahInitGCLABClosure init_gclabs;
624 Threads::threads_do(&init_gclabs);
625 gc_threads_do(&init_gclabs);
626
627 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
628 // Now, we will let WorkGang to initialize gclab when new worker is created.
629 _workers->set_initialize_gclab();
630
631 _scm->initialize(_max_workers);
632 _full_gc->initialize(_gc_timer);
633
634 ref_processing_init();
635
636 _heuristics->initialize();
637 }
638
639 size_t ShenandoahHeap::used() const {
640 return OrderAccess::load_acquire(&_used);
641 }
642
643 size_t ShenandoahHeap::committed() const {
644 OrderAccess::acquire();
645 return _committed;
646 }
647
648 void ShenandoahHeap::increase_committed(size_t bytes) {
649 assert_heaplock_or_safepoint();
650 _committed += bytes;
651 }
652
653 void ShenandoahHeap::decrease_committed(size_t bytes) {
654 assert_heaplock_or_safepoint();
655 _committed -= bytes;
656 }
657
658 void ShenandoahHeap::increase_used(size_t bytes) {
659 Atomic::add(bytes, &_used);
660 }
661
662 void ShenandoahHeap::set_used(size_t bytes) {
663 OrderAccess::release_store_fence(&_used, bytes);
664 }
665
666 void ShenandoahHeap::decrease_used(size_t bytes) {
667 assert(used() >= bytes, "never decrease heap size by more than we've left");
668 Atomic::sub(bytes, &_used);
669 }
670
671 void ShenandoahHeap::increase_allocated(size_t bytes) {
672 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
673 }
674
675 void ShenandoahHeap::notify_alloc(size_t words, bool waste) {
676 size_t bytes = words * HeapWordSize;
677 if (!waste) {
678 increase_used(bytes);
679 }
680 increase_allocated(bytes);
681 if (ShenandoahPacing) {
682 control_thread()->pacing_notify_alloc(words);
683 if (waste) {
684 pacer()->claim_for_alloc(words, true);
685 }
686 }
687 }
688
689 size_t ShenandoahHeap::capacity() const {
690 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
691 }
692
693 bool ShenandoahHeap::is_maximal_no_gc() const {
694 Unimplemented();
695 return true;
696 }
697
698 size_t ShenandoahHeap::max_capacity() const {
699 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
700 }
701
702 size_t ShenandoahHeap::initial_capacity() const {
703 return _initial_size;
704 }
705
706 bool ShenandoahHeap::is_in(const void* p) const {
707 HeapWord* heap_base = (HeapWord*) base();
708 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
709 return p >= heap_base && p < last_region_end;
710 }
711
712 bool ShenandoahHeap::is_scavengable(oop p) {
713 return true;
714 }
715
716 void ShenandoahHeap::op_uncommit(double shrink_before) {
717 assert (ShenandoahUncommit, "should be enabled");
718
719 size_t count = 0;
720 for (size_t i = 0; i < num_regions(); i++) {
721 ShenandoahHeapRegion* r = get_region(i);
722 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
723 ShenandoahHeapLocker locker(lock());
724 if (r->is_empty_committed()) {
725 r->make_uncommitted();
726 count++;
727 }
728 }
729 SpinPause(); // allow allocators to take the lock
730 }
731
732 if (count > 0) {
733 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
734 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
735 control_thread()->notify_heap_changed();
736 }
737
738 // Allocations happen during uncommits, record peak after the phase:
739 heuristics()->record_peak_occupancy();
740 }
741
742 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
743 // New object should fit the GCLAB size
744 size_t min_size = MAX2(size, PLAB::min_size());
745
746 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
747 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
748 new_size = MIN2(new_size, PLAB::max_size());
749 new_size = MAX2(new_size, PLAB::min_size());
750
751 // Record new heuristic value even if we take any shortcut. This captures
752 // the case when moderately-sized objects always take a shortcut. At some point,
753 // heuristics should catch up with them.
754 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
755
756 if (new_size < size) {
757 // New size still does not fit the object. Fall back to shared allocation.
758 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
759 return NULL;
760 }
761
762 // Retire current GCLAB, and allocate a new one.
763 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
764 gclab->retire();
765
766 size_t actual_size = 0;
767 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
768 if (gclab_buf == NULL) {
769 return NULL;
770 }
771
772 assert (size <= actual_size, "allocation should fit");
773
774 if (ZeroTLAB) {
775 // ..and clear it.
776 Copy::zero_to_words(gclab_buf, actual_size);
777 } else {
778 // ...and zap just allocated object.
779 #ifdef ASSERT
780 // Skip mangling the space corresponding to the object header to
781 // ensure that the returned space is not considered parsable by
782 // any concurrent GC thread.
783 size_t hdr_size = oopDesc::header_size();
784 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
785 #endif // ASSERT
786 }
787 gclab->set_buf(gclab_buf, actual_size);
788 return gclab->allocate(size);
789 }
790
791 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
792 size_t requested_size,
793 size_t* actual_size) {
794 #ifdef ASSERT
795 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", requested_size * HeapWordSize);
796 #endif
797 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_tlab(min_size, requested_size);
798 HeapWord* res = allocate_memory(req);
799 if (res != NULL) {
800 *actual_size = req.actual_size();
801 } else {
802 *actual_size = 0;
803 }
804 return res;
805 }
806
807 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
808 size_t word_size,
809 size_t* actual_size) {
810 #ifdef ASSERT
811 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
812 #endif
813 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_gclab(min_size, word_size);
814 HeapWord* res = allocate_memory(req);
815 if (res != NULL) {
816 *actual_size = req.actual_size();
817 } else {
818 *actual_size = 0;
819 }
820 return res;
821 }
822
823 ShenandoahHeap* ShenandoahHeap::heap() {
824 CollectedHeap* heap = Universe::heap();
825 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
826 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
827 return (ShenandoahHeap*) heap;
828 }
829
830 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
831 CollectedHeap* heap = Universe::heap();
832 return (ShenandoahHeap*) heap;
833 }
834
835 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocationRequest& req) {
836 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
837
838 intptr_t pacer_epoch = 0;
839 bool in_new_region = false;
840 HeapWord* result = NULL;
841
842 if (req.is_mutator_alloc()) {
843 if (ShenandoahPacing) {
844 pacer()->pace_for_alloc(req.size());
845 pacer_epoch = pacer()->epoch();
846 }
847
848 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
849 result = allocate_memory_under_lock(req, in_new_region);
850 }
851
852 // Allocation failed, block until control thread reacted, then retry allocation.
853 //
854 // It might happen that one of the threads requesting allocation would unblock
855 // way later after GC happened, only to fail the second allocation, because
856 // other threads have already depleted the free storage. In this case, a better
857 // strategy is to try again, as long as GC makes progress.
858 //
859 // Then, we need to make sure the allocation was retried after at least one
860 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
861
862 size_t tries = 0;
863
864 while (result == NULL && last_gc_made_progress()) {
865 tries++;
866 control_thread()->handle_alloc_failure(req.size());
867 result = allocate_memory_under_lock(req, in_new_region);
868 }
869
870 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
871 tries++;
872 control_thread()->handle_alloc_failure(req.size());
873 result = allocate_memory_under_lock(req, in_new_region);
874 }
875
876 } else {
877 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
878 result = allocate_memory_under_lock(req, in_new_region);
879 // Do not call handle_alloc_failure() here, because we cannot block.
880 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
881 }
882
883 if (in_new_region) {
884 control_thread()->notify_heap_changed();
885 }
886
887 if (result != NULL) {
888 size_t requested = req.size();
889 size_t actual = req.actual_size();
890
891 assert (req.is_lab_alloc() || (requested == actual),
892 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
893 alloc_type_to_string(req.type()), requested, actual);
894
895 notify_alloc(actual, false);
896
897 // If we requested more than we were granted, give the rest back to pacer.
898 // This only matters if we are in the same pacing epoch: do not try to unpace
899 // over the budget for the other phase.
900 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
901 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
902 }
903 }
904
905 return result;
906 }
907
908 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocationRequest& req, bool& in_new_region) {
909 ShenandoahHeapLocker locker(lock());
910 return _free_set->allocate(req, in_new_region);
911 }
912
913 class ShenandoahObjAllocator : public ObjAllocator {
914 public:
915 ShenandoahObjAllocator(Klass* klass, size_t word_size, Thread* thread) :
916 ObjAllocator(klass, word_size, thread) {}
917
918 virtual HeapWord* mem_allocate(Allocation& allocation) {
919 // Allocate object.
920 _word_size += BrooksPointer::word_size();
921 HeapWord* result = ObjAllocator::mem_allocate(allocation);
922 _word_size -= BrooksPointer::word_size();
923 // Initialize brooks-pointer
924 if (result != NULL) {
925 result += BrooksPointer::word_size();
926 BrooksPointer::initialize(oop(result));
927 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
928 }
929 return result;
930 }
931 };
932
933 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
934 ShenandoahObjAllocator allocator(klass, size, THREAD);
935 return allocator.allocate();
936 }
937
938 class ShenandoahObjArrayAllocator : public ObjArrayAllocator {
939 public:
940 ShenandoahObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero,
941 Thread* thread) :
942 ObjArrayAllocator(klass, word_size, length, do_zero, thread) {}
943
944 virtual HeapWord* mem_allocate(Allocation& allocation) {
945 // Allocate object.
946 _word_size += BrooksPointer::word_size();
947 HeapWord* result = ObjArrayAllocator::mem_allocate(allocation);
948 _word_size -= BrooksPointer::word_size();
949 if (result != NULL) {
950 result += BrooksPointer::word_size();
951 BrooksPointer::initialize(oop(result));
952 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
953 }
954 return result;
955 }
956
957 };
958
959 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
960 ShenandoahObjArrayAllocator allocator(klass, size, length, do_zero, THREAD);
961 return allocator.allocate();
962 }
963
964 class ShenandoahClassAllocator : public ClassAllocator {
965 public:
966 ShenandoahClassAllocator(Klass* klass, size_t word_size, Thread* thread) :
967 ClassAllocator(klass, word_size, thread) {}
968
969 virtual HeapWord* mem_allocate(Allocation& allocation) {
970 _word_size += BrooksPointer::word_size();
971 HeapWord* result = ClassAllocator::mem_allocate(allocation);
972 _word_size -= BrooksPointer::word_size();
973 if (result != NULL) {
974 result += BrooksPointer::word_size();
975 BrooksPointer::initialize(oop(result));
976 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
977 }
978 return result;
979 }
980
981 };
982
983 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
984 ShenandoahClassAllocator allocator(klass, size, THREAD);
985 return allocator.allocate();
986 }
987
988 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
989 bool* gc_overhead_limit_was_exceeded) {
990 ShenandoahAllocationRequest req = ShenandoahAllocationRequest::for_shared(size);
991 return allocate_memory(req);
992 }
993
994 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
995 HeapWord* obj = tlab_post_allocation_setup(start);
996 CollectedHeap::fill_with_object(obj, end);
997 }
998
999 class ShenandoahEvacuateUpdateRootsClosure: public BasicOopIterateClosure {
1000 private:
1001 ShenandoahHeap* _heap;
1002 Thread* _thread;
1003 public:
1004 ShenandoahEvacuateUpdateRootsClosure() :
1005 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
1006 }
1007
1008 private:
1009 template <class T>
1010 void do_oop_work(T* p) {
1011 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
1012
1013 T o = RawAccess<>::oop_load(p);
1014 if (! CompressedOops::is_null(o)) {
1015 oop obj = CompressedOops::decode_not_null(o);
1016 if (_heap->in_collection_set(obj)) {
1017 shenandoah_assert_marked_complete(p, obj);
1018 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1019 if (oopDesc::unsafe_equals(resolved, obj)) {
1020 resolved = _heap->evacuate_object(obj, _thread);
1021 }
1022 RawAccess<IS_NOT_NULL>::oop_store(p, resolved);
1023 }
1024 }
1025 }
1026
1027 public:
1028 void do_oop(oop* p) {
1029 do_oop_work(p);
1030 }
1031 void do_oop(narrowOop* p) {
1032 do_oop_work(p);
1033 }
1034 };
1035
1036 class ShenandoahEvacuateRootsClosure: public BasicOopIterateClosure {
1037 private:
1038 ShenandoahHeap* _heap;
1039 Thread* _thread;
1040 public:
1041 ShenandoahEvacuateRootsClosure() :
1042 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
1043 }
1044
1045 private:
1046 template <class T>
1047 void do_oop_work(T* p) {
1048 T o = RawAccess<>::oop_load(p);
1049 if (! CompressedOops::is_null(o)) {
1050 oop obj = CompressedOops::decode_not_null(o);
1051 if (_heap->in_collection_set(obj)) {
1052 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1053 if (oopDesc::unsafe_equals(resolved, obj)) {
1054 _heap->evacuate_object(obj, _thread);
1055 }
1056 }
1057 }
1058 }
1059
1060 public:
1061 void do_oop(oop* p) {
1062 do_oop_work(p);
1063 }
1064 void do_oop(narrowOop* p) {
1065 do_oop_work(p);
1066 }
1067 };
1068
1069 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
1070 private:
1071 ShenandoahHeap* const _heap;
1072 Thread* const _thread;
1073 public:
1074 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
1075 _heap(heap), _thread(Thread::current()) {}
1076
1077 void do_object(oop p) {
1078 shenandoah_assert_marked_complete(NULL, p);
1079 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
1080 _heap->evacuate_object(p, _thread);
1081 }
1082 }
1083 };
1084
1085 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
1086 private:
1087 ShenandoahHeap* const _sh;
1088 ShenandoahCollectionSet* const _cs;
1089 ShenandoahSharedFlag _claimed_codecache;
1090
1091 public:
1092 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
1093 ShenandoahCollectionSet* cs) :
1094 AbstractGangTask("Parallel Evacuation Task"),
1095 _cs(cs),
1096 _sh(sh)
1097 {}
1098
1099 void work(uint worker_id) {
1100 ShenandoahWorkerSession worker_session(worker_id);
1101 ShenandoahEvacOOMScope oom_evac_scope;
1102 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
1103
1104 // If concurrent code cache evac is enabled, evacuate it here.
1105 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
1106 // nmethods. The update would be handled elsewhere.
1107 if (ShenandoahConcurrentEvacCodeRoots && _claimed_codecache.try_set()) {
1108 ShenandoahEvacuateRootsClosure cl;
1109 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1110 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
1111 CodeCache::blobs_do(&blobs);
1112 }
1113
1114 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
1115 ShenandoahHeapRegion* r;
1116 while ((r =_cs->claim_next()) != NULL) {
1117 log_develop_trace(gc, region)("Thread " INT32_FORMAT " claimed Heap Region " SIZE_FORMAT,
1118 worker_id,
1119 r->region_number());
1120
1121 assert(r->has_live(), "all-garbage regions are reclaimed early");
1122 _sh->marked_object_iterate(r, &cl);
1123
1124 if (ShenandoahPacing) {
1125 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1126 }
1127
1128 if (_sh->check_cancelled_gc_and_yield()) {
1129 log_develop_trace(gc, region)("Cancelled GC while evacuating region " SIZE_FORMAT, r->region_number());
1130 break;
1131 }
1132 }
1133 }
1134 };
1135
1136 void ShenandoahHeap::trash_cset_regions() {
1137 ShenandoahHeapLocker locker(lock());
1138
1139 ShenandoahCollectionSet* set = collection_set();
1140 ShenandoahHeapRegion* r;
1141 set->clear_current_index();
1142 while ((r = set->next()) != NULL) {
1143 r->make_trash();
1144 }
1145 collection_set()->clear();
1146 }
1147
1148 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1149 st->print_cr("Heap Regions:");
1150 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1151 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1152 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1153 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1154
1155 for (size_t i = 0; i < num_regions(); i++) {
1156 get_region(i)->print_on(st);
1157 }
1158 }
1159
1160 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1161 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1162
1163 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
1164 size_t size = humongous_obj->size() + BrooksPointer::word_size();
1165 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1166 size_t index = start->region_number() + required_regions - 1;
1167
1168 assert(!start->has_live(), "liveness must be zero");
1169 log_trace(gc, humongous)("Reclaiming " SIZE_FORMAT " humongous regions for object of size: " SIZE_FORMAT " words", required_regions, size);
1170
1171 for(size_t i = 0; i < required_regions; i++) {
1172 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1173 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1174 ShenandoahHeapRegion* region = get_region(index --);
1175
1176 LogTarget(Trace, gc, humongous) lt;
1177 if (lt.is_enabled()) {
1178 ResourceMark rm;
1179 LogStream ls(lt);
1180 region->print_on(&ls);
1181 }
1182
1183 assert(region->is_humongous(), "expect correct humongous start or continuation");
1184 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1185
1186 region->make_trash();
1187 }
1188 }
1189
1190 #ifdef ASSERT
1191 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1192 bool heap_region_do(ShenandoahHeapRegion* r) {
1193 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1194 return false;
1195 }
1196 };
1197 #endif
1198
1199 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1200 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1201
1202 if (!cancelled_gc()) {
1203 // Allocations might have happened before we STWed here, record peak:
1204 heuristics()->record_peak_occupancy();
1205
1206 make_parsable(true);
1207
1208 if (ShenandoahVerify) {
1209 verifier()->verify_after_concmark();
1210 }
1211
1212 trash_cset_regions();
1213
1214 // NOTE: This needs to be done during a stop the world pause, because
1215 // putting regions into the collection set concurrently with Java threads
1216 // will create a race. In particular, acmp could fail because when we
1217 // resolve the first operand, the containing region might not yet be in
1218 // the collection set, and thus return the original oop. When the 2nd
1219 // operand gets resolved, the region could be in the collection set
1220 // and the oop gets evacuated. If both operands have originally been
1221 // the same, we get false negatives.
1222
1223 {
1224 ShenandoahHeapLocker locker(lock());
1225 _collection_set->clear();
1226 _free_set->clear();
1227
1228 #ifdef ASSERT
1229 ShenandoahCheckCollectionSetClosure ccsc;
1230 heap_region_iterate(&ccsc);
1231 #endif
1232
1233 heuristics()->choose_collection_set(_collection_set);
1234
1235 _free_set->rebuild();
1236 }
1237
1238 Universe::update_heap_info_at_gc();
1239
1240 if (ShenandoahVerify) {
1241 verifier()->verify_before_evacuation();
1242 }
1243 }
1244 }
1245
1246
1247 class ShenandoahRetireTLABClosure : public ThreadClosure {
1248 private:
1249 bool _retire;
1250
1251 public:
1252 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1253
1254 void do_thread(Thread* thread) {
1255 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1256 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1257 gclab->retire();
1258 }
1259 };
1260
1261 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1262 if (UseTLAB) {
1263 CollectedHeap::ensure_parsability(retire_tlabs);
1264 }
1265 ShenandoahRetireTLABClosure cl(retire_tlabs);
1266 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1267 cl.do_thread(t);
1268 }
1269 gc_threads_do(&cl);
1270 }
1271
1272
1273 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1274 ShenandoahRootEvacuator* _rp;
1275 public:
1276
1277 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1278 AbstractGangTask("Shenandoah evacuate and update roots"),
1279 _rp(rp)
1280 {
1281 // Nothing else to do.
1282 }
1283
1284 void work(uint worker_id) {
1285 ShenandoahWorkerSession worker_session(worker_id);
1286 ShenandoahEvacOOMScope oom_evac_scope;
1287 ShenandoahEvacuateUpdateRootsClosure cl;
1288
1289 if (ShenandoahConcurrentEvacCodeRoots) {
1290 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1291 } else {
1292 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1293 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1294 }
1295 }
1296 };
1297
1298 class ShenandoahFixRootsTask : public AbstractGangTask {
1299 ShenandoahRootEvacuator* _rp;
1300 public:
1301
1302 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1303 AbstractGangTask("Shenandoah update roots"),
1304 _rp(rp)
1305 {
1306 // Nothing else to do.
1307 }
1308
1309 void work(uint worker_id) {
1310 ShenandoahWorkerSession worker_session(worker_id);
1311 ShenandoahEvacOOMScope oom_evac_scope;
1312 ShenandoahUpdateRefsClosure cl;
1313 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1314
1315 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1316 }
1317 };
1318
1319 void ShenandoahHeap::evacuate_and_update_roots() {
1320
1321 #if defined(COMPILER2) || INCLUDE_JVMCI
1322 DerivedPointerTable::clear();
1323 #endif
1324 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1325
1326 {
1327 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1328 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1329 workers()->run_task(&roots_task);
1330 }
1331
1332 #if defined(COMPILER2) || INCLUDE_JVMCI
1333 DerivedPointerTable::update_pointers();
1334 #endif
1335 if (cancelled_gc()) {
1336 fixup_roots();
1337 }
1338 }
1339
1340 void ShenandoahHeap::fixup_roots() {
1341 assert(cancelled_gc(), "Only after concurrent cycle failed");
1342
1343 // If initial evacuation has been cancelled, we need to update all references
1344 // after all workers have finished. Otherwise we might run into the following problem:
1345 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1346 // GC thread 2 evacuates the same object X to to-space
1347 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1348 // clear() and update_pointers() must always be called in pairs,
1349 // cannot nest with above clear()/update_pointers().
1350 #if defined(COMPILER2) || INCLUDE_JVMCI
1351 DerivedPointerTable::clear();
1352 #endif
1353 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1354 ShenandoahFixRootsTask update_roots_task(&rp);
1355 workers()->run_task(&update_roots_task);
1356 #if defined(COMPILER2) || INCLUDE_JVMCI
1357 DerivedPointerTable::update_pointers();
1358 #endif
1359 }
1360
1361 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1362 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1363
1364 CodeBlobToOopClosure blobsCl(cl, false);
1365 CLDToOopClosure cldCl(cl);
1366
1367 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1368 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1369 }
1370
1371 bool ShenandoahHeap::supports_tlab_allocation() const {
1372 return true;
1373 }
1374
1375 // Returns size in bytes
1376 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1377 if (ShenandoahElasticTLAB) {
1378 // With Elastic TLABs, return the max allowed size, and let the allocation path
1379 // figure out the safe size for current allocation.
1380 return ShenandoahHeapRegion::max_tlab_size_bytes();
1381 } else {
1382 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1383 }
1384 }
1385
1386 size_t ShenandoahHeap::max_tlab_size() const {
1387 // Returns size in words
1388 return ShenandoahHeapRegion::max_tlab_size_words();
1389 }
1390
1391 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1392 public:
1393 void do_thread(Thread* thread) {
1394 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1395 gclab->retire();
1396 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1397 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1398 }
1399 }
1400 };
1401
1402 void ShenandoahHeap::retire_and_reset_gclabs() {
1403 ShenandoahRetireAndResetGCLABClosure cl;
1404 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1405 cl.do_thread(t);
1406 }
1407 gc_threads_do(&cl);
1408 }
1409
1410 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1411 return true;
1412 }
1413
1414 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1415 // Overridden to do nothing.
1416 return new_obj;
1417 }
1418
1419 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1420 return true;
1421 }
1422
1423 bool ShenandoahHeap::card_mark_must_follow_store() const {
1424 return false;
1425 }
1426
1427 void ShenandoahHeap::collect(GCCause::Cause cause) {
1428 control_thread()->handle_explicit_gc(cause);
1429 }
1430
1431 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1432 //assert(false, "Shouldn't need to do full collections");
1433 }
1434
1435 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1436 Unimplemented();
1437 return NULL;
1438
1439 }
1440
1441 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1442 return _shenandoah_policy;
1443 }
1444
1445
1446 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1447 Space* sp = heap_region_containing(addr);
1448 if (sp != NULL) {
1449 return sp->block_start(addr);
1450 }
1451 return NULL;
1452 }
1453
1454 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1455 Space* sp = heap_region_containing(addr);
1456 assert(sp != NULL, "block_size of address outside of heap");
1457 return sp->block_size(addr);
1458 }
1459
1460 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1461 Space* sp = heap_region_containing(addr);
1462 return sp->block_is_obj(addr);
1463 }
1464
1465 jlong ShenandoahHeap::millis_since_last_gc() {
1466 return 0;
1467 }
1468
1469 void ShenandoahHeap::prepare_for_verify() {
1470 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1471 make_parsable(false);
1472 }
1473 }
1474
1475 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1476 workers()->print_worker_threads_on(st);
1477 if (ShenandoahStringDedup::is_enabled()) {
1478 ShenandoahStringDedup::print_worker_threads_on(st);
1479 }
1480 }
1481
1482 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1483 workers()->threads_do(tcl);
1484 if (ShenandoahStringDedup::is_enabled()) {
1485 ShenandoahStringDedup::threads_do(tcl);
1486 }
1487 }
1488
1489 void ShenandoahHeap::print_tracing_info() const {
1490 LogTarget(Info, gc, stats) lt;
1491 if (lt.is_enabled()) {
1492 ResourceMark rm;
1493 LogStream ls(lt);
1494
1495 phase_timings()->print_on(&ls);
1496
1497 ls.cr();
1498 ls.cr();
1499
1500 shenandoahPolicy()->print_gc_stats(&ls);
1501
1502 ls.cr();
1503 ls.cr();
1504
1505 if (ShenandoahPacing) {
1506 pacer()->print_on(&ls);
1507 }
1508
1509 ls.cr();
1510 ls.cr();
1511
1512 if (ShenandoahAllocationTrace) {
1513 assert(alloc_tracker() != NULL, "Must be");
1514 alloc_tracker()->print_on(&ls);
1515 } else {
1516 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1517 }
1518 }
1519 }
1520
1521 void ShenandoahHeap::verify(VerifyOption vo) {
1522 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1523 if (ShenandoahVerify) {
1524 verifier()->verify_generic(vo);
1525 } else {
1526 // TODO: Consider allocating verification bitmaps on demand,
1527 // and turn this on unconditionally.
1528 }
1529 }
1530 }
1531 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1532 return _free_set->capacity();
1533 }
1534
1535 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1536 private:
1537 MarkBitMap* _bitmap;
1538 Stack<oop,mtGC>* _oop_stack;
1539
1540 template <class T>
1541 void do_oop_work(T* p) {
1542 T o = RawAccess<>::oop_load(p);
1543 if (!CompressedOops::is_null(o)) {
1544 oop obj = CompressedOops::decode_not_null(o);
1545 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1546 assert(oopDesc::is_oop(obj), "must be a valid oop");
1547 if (!_bitmap->isMarked((HeapWord*) obj)) {
1548 _bitmap->mark((HeapWord*) obj);
1549 _oop_stack->push(obj);
1550 }
1551 }
1552 }
1553 public:
1554 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1555 _bitmap(bitmap), _oop_stack(oop_stack) {}
1556 void do_oop(oop* p) { do_oop_work(p); }
1557 void do_oop(narrowOop* p) { do_oop_work(p); }
1558 };
1559
1560 /*
1561 * This is public API, used in preparation of object_iterate().
1562 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1563 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1564 * control, we call SH::make_tlabs_parsable().
1565 */
1566 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1567 // No-op.
1568 }
1569
1570 /*
1571 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1572 *
1573 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1574 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1575 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1576 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1577 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1578 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1579 * wiped the bitmap in preparation for next marking).
1580 *
1581 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1582 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1583 * is allowed to report dead objects, but is not required to do so.
1584 */
1585 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1586 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1587 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1588 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1589 return;
1590 }
1591
1592 // Reset bitmap
1593 MemRegion mr = MemRegion(_aux_bit_map.startWord(), _aux_bit_map.endWord());
1594 _aux_bit_map.clear_range_large(mr);
1595
1596 Stack<oop,mtGC> oop_stack;
1597
1598 // First, we process all GC roots. This populates the work stack with initial objects.
1599 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1600 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1601 CLDToOopClosure clds(&oops, false);
1602 CodeBlobToOopClosure blobs(&oops, false);
1603 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1604
1605 // Work through the oop stack to traverse heap.
1606 while (! oop_stack.is_empty()) {
1607 oop obj = oop_stack.pop();
1608 assert(oopDesc::is_oop(obj), "must be a valid oop");
1609 cl->do_object(obj);
1610 obj->oop_iterate(&oops);
1611 }
1612
1613 assert(oop_stack.is_empty(), "should be empty");
1614
1615 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1616 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1617 }
1618 }
1619
1620 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1621 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1622 object_iterate(cl);
1623 }
1624
1625 // Apply blk->heap_region_do() on all committed regions in address order,
1626 // terminating the iteration early if heap_region_do() returns true.
1627 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1628 for (size_t i = 0; i < num_regions(); i++) {
1629 ShenandoahHeapRegion* current = get_region(i);
1630 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1631 continue;
1632 }
1633 if (skip_cset_regions && in_collection_set(current)) {
1634 continue;
1635 }
1636 if (blk->heap_region_do(current)) {
1637 return;
1638 }
1639 }
1640 }
1641
1642 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1643 private:
1644 ShenandoahHeap* sh;
1645 public:
1646 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1647
1648 bool heap_region_do(ShenandoahHeapRegion* r) {
1649 r->clear_live_data();
1650 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1651 return false;
1652 }
1653 };
1654
1655 void ShenandoahHeap::op_init_mark() {
1656 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1657
1658 assert(is_next_bitmap_clear(), "need clear marking bitmap");
1659
1660 if (ShenandoahVerify) {
1661 verifier()->verify_before_concmark();
1662 }
1663
1664 {
1665 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1666 accumulate_statistics_all_tlabs();
1667 }
1668
1669 set_concurrent_mark_in_progress(true);
1670 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1671 {
1672 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1673 make_parsable(true);
1674 }
1675
1676 {
1677 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1678 ShenandoahClearLivenessClosure clc(this);
1679 heap_region_iterate(&clc);
1680 }
1681
1682 // Make above changes visible to worker threads
1683 OrderAccess::fence();
1684
1685 concurrentMark()->init_mark_roots();
1686
1687 if (UseTLAB) {
1688 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1689 resize_all_tlabs();
1690 }
1691
1692 if (ShenandoahPacing) {
1693 pacer()->setup_for_mark();
1694 }
1695 }
1696
1697 void ShenandoahHeap::op_mark() {
1698 concurrentMark()->mark_from_roots();
1699
1700 // Allocations happen during concurrent mark, record peak after the phase:
1701 heuristics()->record_peak_occupancy();
1702 }
1703
1704 void ShenandoahHeap::op_final_mark() {
1705 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1706
1707 // It is critical that we
1708 // evacuate roots right after finishing marking, so that we don't
1709 // get unmarked objects in the roots.
1710
1711 if (!cancelled_gc()) {
1712 concurrentMark()->finish_mark_from_roots();
1713 stop_concurrent_marking();
1714
1715 {
1716 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1717
1718 // All allocations past TAMS are implicitly live, adjust the region data.
1719 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1720 for (size_t i = 0; i < num_regions(); i++) {
1721 ShenandoahHeapRegion* r = get_region(i);
1722 if (!r->is_active()) continue;
1723
1724 HeapWord* tams = complete_top_at_mark_start(r->bottom());
1725 HeapWord* top = r->top();
1726 if (top > tams) {
1727 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1728 }
1729 }
1730 }
1731
1732 {
1733 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1734 prepare_for_concurrent_evacuation();
1735 }
1736
1737 // If collection set has candidates, start evacuation.
1738 // Otherwise, bypass the rest of the cycle.
1739 if (!collection_set()->is_empty()) {
1740 set_evacuation_in_progress(true);
1741 // From here on, we need to update references.
1742 set_has_forwarded_objects(true);
1743
1744 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1745 evacuate_and_update_roots();
1746 }
1747
1748 if (ShenandoahPacing) {
1749 pacer()->setup_for_evac();
1750 }
1751 } else {
1752 concurrentMark()->cancel();
1753 stop_concurrent_marking();
1754
1755 if (process_references()) {
1756 // Abandon reference processing right away: pre-cleaning must have failed.
1757 ReferenceProcessor *rp = ref_processor();
1758 rp->disable_discovery();
1759 rp->abandon_partial_discovery();
1760 rp->verify_no_references_recorded();
1761 }
1762 }
1763 }
1764
1765 void ShenandoahHeap::op_final_evac() {
1766 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1767
1768 set_evacuation_in_progress(false);
1769
1770 retire_and_reset_gclabs();
1771
1772 if (ShenandoahVerify) {
1773 verifier()->verify_after_evacuation();
1774 }
1775 }
1776
1777 void ShenandoahHeap::op_evac() {
1778
1779 LogTarget(Trace, gc, region) lt_region;
1780 LogTarget(Trace, gc, cset) lt_cset;
1781
1782 if (lt_region.is_enabled()) {
1783 ResourceMark rm;
1784 LogStream ls(lt_region);
1785 ls.print_cr("All available regions:");
1786 print_heap_regions_on(&ls);
1787 }
1788
1789 if (lt_cset.is_enabled()) {
1790 ResourceMark rm;
1791 LogStream ls(lt_cset);
1792 ls.print_cr("Collection set (" SIZE_FORMAT " regions):", _collection_set->count());
1793 _collection_set->print_on(&ls);
1794
1795 ls.print_cr("Free set:");
1796 _free_set->print_on(&ls);
1797 }
1798
1799 ShenandoahParallelEvacuationTask task(this, _collection_set);
1800 workers()->run_task(&task);
1801
1802 if (lt_cset.is_enabled()) {
1803 ResourceMark rm;
1804 LogStream ls(lt_cset);
1805 ls.print_cr("After evacuation collection set (" SIZE_FORMAT " regions):",
1806 _collection_set->count());
1807 _collection_set->print_on(&ls);
1808
1809 ls.print_cr("After evacuation free set:");
1810 _free_set->print_on(&ls);
1811 }
1812
1813 if (lt_region.is_enabled()) {
1814 ResourceMark rm;
1815 LogStream ls(lt_region);
1816 ls.print_cr("All regions after evacuation:");
1817 print_heap_regions_on(&ls);
1818 }
1819
1820 // Allocations happen during evacuation, record peak after the phase:
1821 heuristics()->record_peak_occupancy();
1822 }
1823
1824 void ShenandoahHeap::op_updaterefs() {
1825 update_heap_references(true);
1826
1827 // Allocations happen during update-refs, record peak after the phase:
1828 heuristics()->record_peak_occupancy();
1829 }
1830
1831 void ShenandoahHeap::op_cleanup() {
1832 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1833 free_set()->recycle_trash();
1834
1835 // Allocations happen during cleanup, record peak after the phase:
1836 heuristics()->record_peak_occupancy();
1837 }
1838
1839 void ShenandoahHeap::op_cleanup_bitmaps() {
1840 op_cleanup();
1841
1842 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1843 reset_next_mark_bitmap();
1844
1845 // Allocations happen during bitmap cleanup, record peak after the phase:
1846 heuristics()->record_peak_occupancy();
1847 }
1848
1849 void ShenandoahHeap::op_cleanup_traversal() {
1850
1851 {
1852 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1853 reset_next_mark_bitmap_traversal();
1854 }
1855
1856 op_cleanup();
1857
1858 // Allocations happen during bitmap cleanup, record peak after the phase:
1859 heuristics()->record_peak_occupancy();
1860 }
1861
1862 void ShenandoahHeap::op_preclean() {
1863 concurrentMark()->preclean_weak_refs();
1864
1865 // Allocations happen during concurrent preclean, record peak after the phase:
1866 heuristics()->record_peak_occupancy();
1867 }
1868
1869 void ShenandoahHeap::op_init_traversal() {
1870 traversal_gc()->init_traversal_collection();
1871 }
1872
1873 void ShenandoahHeap::op_traversal() {
1874 traversal_gc()->concurrent_traversal_collection();
1875 }
1876
1877 void ShenandoahHeap::op_final_traversal() {
1878 traversal_gc()->final_traversal_collection();
1879 }
1880
1881 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1882 ShenandoahMetricsSnapshot metrics;
1883 metrics.snap_before();
1884
1885 full_gc()->do_it(cause);
1886 if (UseTLAB) {
1887 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1888 resize_all_tlabs();
1889 }
1890
1891 metrics.snap_after();
1892 metrics.print();
1893
1894 if (metrics.is_good_progress("Full GC")) {
1895 _progress_last_gc.set();
1896 } else {
1897 // Nothing to do. Tell the allocation path that we have failed to make
1898 // progress, and it can finally fail.
1899 _progress_last_gc.unset();
1900 }
1901 }
1902
1903 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1904 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1905 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1906 // some phase, we have to upgrade the Degenerate GC to Full GC.
1907
1908 clear_cancelled_gc();
1909
1910 ShenandoahMetricsSnapshot metrics;
1911 metrics.snap_before();
1912
1913 switch (point) {
1914 case _degenerated_evac:
1915 // Not possible to degenerate from here, upgrade to Full GC right away.
1916 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1917 op_degenerated_fail();
1918 return;
1919
1920 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1921 // but enters it at different points, depending on which concurrent phase had
1922 // degenerated.
1923
1924 case _degenerated_traversal:
1925 {
1926 ShenandoahHeapLocker locker(lock());
1927 collection_set()->clear_current_index();
1928 for (size_t i = 0; i < collection_set()->count(); i++) {
1929 ShenandoahHeapRegion* r = collection_set()->next();
1930 r->make_regular_bypass();
1931 }
1932 collection_set()->clear();
1933 }
1934 op_final_traversal();
1935 op_cleanup_traversal();
1936 return;
1937
1938 case _degenerated_outside_cycle:
1939 if (heuristics()->can_do_traversal_gc()) {
1940 // Not possible to degenerate from here, upgrade to Full GC right away.
1941 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1942 op_degenerated_fail();
1943 return;
1944 }
1945 op_init_mark();
1946 if (cancelled_gc()) {
1947 op_degenerated_fail();
1948 return;
1949 }
1950
1951 case _degenerated_mark:
1952 op_final_mark();
1953 if (cancelled_gc()) {
1954 op_degenerated_fail();
1955 return;
1956 }
1957
1958 op_cleanup();
1959
1960 // If heuristics thinks we should do the cycle, this flag would be set,
1961 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1962 if (is_evacuation_in_progress()) {
1963 op_evac();
1964 if (cancelled_gc()) {
1965 op_degenerated_fail();
1966 return;
1967 }
1968 }
1969
1970 // If heuristics thinks we should do the cycle, this flag would be set,
1971 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1972 if (has_forwarded_objects()) {
1973 op_init_updaterefs();
1974 if (cancelled_gc()) {
1975 op_degenerated_fail();
1976 return;
1977 }
1978 }
1979
1980 case _degenerated_updaterefs:
1981 if (has_forwarded_objects()) {
1982 op_final_updaterefs();
1983 if (cancelled_gc()) {
1984 op_degenerated_fail();
1985 return;
1986 }
1987 }
1988
1989 op_cleanup_bitmaps();
1990 break;
1991
1992 default:
1993 ShouldNotReachHere();
1994 }
1995
1996 if (ShenandoahVerify) {
1997 verifier()->verify_after_degenerated();
1998 }
1999
2000 metrics.snap_after();
2001 metrics.print();
2002
2003 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
2004 // because that probably means the heap is overloaded and/or fragmented.
2005 if (!metrics.is_good_progress("Degenerated GC")) {
2006 _progress_last_gc.unset();
2007 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
2008 op_degenerated_futile();
2009 } else {
2010 _progress_last_gc.set();
2011 }
2012 }
2013
2014 void ShenandoahHeap::op_degenerated_fail() {
2015 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
2016 shenandoahPolicy()->record_degenerated_upgrade_to_full();
2017 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2018 }
2019
2020 void ShenandoahHeap::op_degenerated_futile() {
2021 shenandoahPolicy()->record_degenerated_upgrade_to_full();
2022 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2023 }
2024
2025 void ShenandoahHeap::swap_mark_bitmaps() {
2026 // Swap bitmaps.
2027 MarkBitMap* tmp1 = _complete_mark_bit_map;
2028 _complete_mark_bit_map = _next_mark_bit_map;
2029 _next_mark_bit_map = tmp1;
2030
2031 // Swap top-at-mark-start pointers
2032 HeapWord** tmp2 = _complete_top_at_mark_starts;
2033 _complete_top_at_mark_starts = _next_top_at_mark_starts;
2034 _next_top_at_mark_starts = tmp2;
2035
2036 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
2037 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
2038 _next_top_at_mark_starts_base = tmp3;
2039 }
2040
2041
2042 void ShenandoahHeap::stop_concurrent_marking() {
2043 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
2044 if (!cancelled_gc()) {
2045 // If we needed to update refs, and concurrent marking has been cancelled,
2046 // we need to finish updating references.
2047 set_has_forwarded_objects(false);
2048 swap_mark_bitmaps();
2049 }
2050 set_concurrent_mark_in_progress(false);
2051
2052 LogTarget(Trace, gc, region) lt;
2053 if (lt.is_enabled()) {
2054 ResourceMark rm;
2055 LogStream ls(lt);
2056 ls.print_cr("Regions at stopping the concurrent mark:");
2057 print_heap_regions_on(&ls);
2058 }
2059 }
2060
2061 void ShenandoahHeap::force_satb_flush_all_threads() {
2062 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
2063 // No need to flush SATBs
2064 return;
2065 }
2066
2067 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2068 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
2069 }
2070 // The threads are not "acquiring" their thread-local data, but it does not
2071 // hurt to "release" the updates here anyway.
2072 OrderAccess::fence();
2073 }
2074
2075 void ShenandoahHeap::set_gc_state_all_threads(char state) {
2076 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2077 ShenandoahThreadLocalData::set_gc_state(t, state);
2078 }
2079 }
2080
2081 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
2082 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
2083 _gc_state.set_cond(mask, value);
2084 set_gc_state_all_threads(_gc_state.raw_value());
2085 }
2086
2087 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
2088 set_gc_state_mask(MARKING, in_progress);
2089 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2090 }
2091
2092 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
2093 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
2094 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2095 }
2096
2097 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2098 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
2099 set_gc_state_mask(EVACUATION, in_progress);
2100 }
2101
2102 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
2103 // Initialize Brooks pointer for the next object
2104 HeapWord* result = obj + BrooksPointer::word_size();
2105 BrooksPointer::initialize(oop(result));
2106 return result;
2107 }
2108
2109 uint ShenandoahHeap::oop_extra_words() {
2110 return BrooksPointer::word_size();
2111 }
2112
2113 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
2114 _heap(ShenandoahHeap::heap_no_check()) {
2115 }
2116
2117 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
2118 _heap(ShenandoahHeap::heap_no_check()) {
2119 }
2120
2121 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
2122 if (CompressedOops::is_null(obj)) {
2123 return false;
2124 }
2125 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
2126 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_mark_in_progress() || _heap->is_concurrent_traversal_in_progress())
2127 return _heap->is_marked_next(obj);
2128 }
2129
2130 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
2131 if (CompressedOops::is_null(obj)) {
2132 return false;
2133 }
2134 shenandoah_assert_not_forwarded(NULL, obj);
2135 return _heap->is_marked_next(obj);
2136 }
2137
2138 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
2139 return has_forwarded_objects() ?
2140 (BoolObjectClosure*) &_forwarded_is_alive :
2141 (BoolObjectClosure*) &_is_alive;
2142 }
2143
2144 void ShenandoahHeap::ref_processing_init() {
2145 MemRegion mr = reserved_region();
2146
2147 _forwarded_is_alive.init(this);
2148 _is_alive.init(this);
2149 assert(_max_workers > 0, "Sanity");
2150
2151 _ref_processor =
2152 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2153 ParallelRefProcEnabled, // MT processing
2154 _max_workers, // Degree of MT processing
2155 true, // MT discovery
2156 _max_workers, // Degree of MT discovery
2157 false, // Reference discovery is not atomic
2158 NULL); // No closure, should be installed before use
2159
2160 shenandoah_assert_rp_isalive_not_installed();
2161 }
2162
2163
2164 GCTracer* ShenandoahHeap::tracer() {
2165 return shenandoahPolicy()->tracer();
2166 }
2167
2168 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2169 return _free_set->used();
2170 }
2171
2172 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2173 if (try_cancel_gc()) {
2174 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2175 log_info(gc)("%s", msg.buffer());
2176 Events::log(Thread::current(), "%s", msg.buffer());
2177 }
2178 }
2179
2180 uint ShenandoahHeap::max_workers() {
2181 return _max_workers;
2182 }
2183
2184 void ShenandoahHeap::stop() {
2185 // The shutdown sequence should be able to terminate when GC is running.
2186
2187 // Step 0. Notify policy to disable event recording.
2188 _shenandoah_policy->record_shutdown();
2189
2190 // Step 1. Notify control thread that we are in shutdown.
2191 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2192 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2193 control_thread()->prepare_for_graceful_shutdown();
2194
2195 // Step 2. Notify GC workers that we are cancelling GC.
2196 cancel_gc(GCCause::_shenandoah_stop_vm);
2197
2198 // Step 3. Wait until GC worker exits normally.
2199 control_thread()->stop();
2200
2201 // Step 4. Stop String Dedup thread if it is active
2202 if (ShenandoahStringDedup::is_enabled()) {
2203 ShenandoahStringDedup::stop();
2204 }
2205 }
2206
2207 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
2208 assert(ClassUnloading || full_gc, "Class unloading should be enabled");
2209
2210 ShenandoahPhaseTimings::Phase phase_root =
2211 full_gc ?
2212 ShenandoahPhaseTimings::full_gc_purge :
2213 ShenandoahPhaseTimings::purge;
2214
2215 ShenandoahPhaseTimings::Phase phase_unload =
2216 full_gc ?
2217 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2218 ShenandoahPhaseTimings::purge_class_unload;
2219
2220 ShenandoahPhaseTimings::Phase phase_cldg =
2221 full_gc ?
2222 ShenandoahPhaseTimings::full_gc_purge_cldg :
2223 ShenandoahPhaseTimings::purge_cldg;
2224
2225 ShenandoahPhaseTimings::Phase phase_par =
2226 full_gc ?
2227 ShenandoahPhaseTimings::full_gc_purge_par :
2228 ShenandoahPhaseTimings::purge_par;
2229
2230 ShenandoahPhaseTimings::Phase phase_par_classes =
2231 full_gc ?
2232 ShenandoahPhaseTimings::full_gc_purge_par_classes :
2233 ShenandoahPhaseTimings::purge_par_classes;
2234
2235 ShenandoahPhaseTimings::Phase phase_par_codecache =
2236 full_gc ?
2237 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
2238 ShenandoahPhaseTimings::purge_par_codecache;
2239
2240 ShenandoahPhaseTimings::Phase phase_par_rmt =
2241 full_gc ?
2242 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
2243 ShenandoahPhaseTimings::purge_par_rmt;
2244
2245 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2246 full_gc ?
2247 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2248 ShenandoahPhaseTimings::purge_par_symbstring;
2249
2250 ShenandoahPhaseTimings::Phase phase_par_sync =
2251 full_gc ?
2252 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2253 ShenandoahPhaseTimings::purge_par_sync;
2254
2255 ShenandoahGCPhase root_phase(phase_root);
2256
2257 BoolObjectClosure* is_alive = is_alive_closure();
2258
2259 bool purged_class;
2260
2261 // Unload classes and purge SystemDictionary.
2262 {
2263 ShenandoahGCPhase phase(phase_unload);
2264 purged_class = SystemDictionary::do_unloading(gc_timer(),
2265 full_gc /* do_cleaning*/ );
2266 }
2267
2268 {
2269 ShenandoahGCPhase phase(phase_par);
2270 uint active = _workers->active_workers();
2271 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
2272 _workers->run_task(&unlink_task);
2273
2274 ShenandoahPhaseTimings* p = phase_timings();
2275 ParallelCleaningTimes times = unlink_task.times();
2276
2277 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2278 // by active workers to get average time per worker, that would add up to wall time.
2279 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2280 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2281 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
2282 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2283 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2284 }
2285
2286 if (ShenandoahStringDedup::is_enabled()) {
2287 ShenandoahPhaseTimings::Phase phase_purge_dedup =
2288 full_gc ?
2289 ShenandoahPhaseTimings::full_gc_purge_string_dedup :
2290 ShenandoahPhaseTimings::purge_string_dedup;
2291 ShenandoahGCPhase phase(phase_purge_dedup);
2292 ShenandoahStringDedup::parallel_cleanup();
2293 }
2294
2295 {
2296 ShenandoahGCPhase phase(phase_cldg);
2297 ClassLoaderDataGraph::purge();
2298 }
2299 }
2300
2301 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2302 set_gc_state_mask(HAS_FORWARDED, cond);
2303 }
2304
2305 bool ShenandoahHeap::last_gc_made_progress() const {
2306 return _progress_last_gc.is_set();
2307 }
2308
2309 void ShenandoahHeap::set_process_references(bool pr) {
2310 _process_references.set_cond(pr);
2311 }
2312
2313 void ShenandoahHeap::set_unload_classes(bool uc) {
2314 _unload_classes.set_cond(uc);
2315 }
2316
2317 bool ShenandoahHeap::process_references() const {
2318 return _process_references.is_set();
2319 }
2320
2321 bool ShenandoahHeap::unload_classes() const {
2322 return _unload_classes.is_set();
2323 }
2324
2325 //fixme this should be in heapregionset
2326 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2327 size_t region_idx = r->region_number() + 1;
2328 ShenandoahHeapRegion* next = get_region(region_idx);
2329 guarantee(next->region_number() == region_idx, "region number must match");
2330 while (next->is_humongous()) {
2331 region_idx = next->region_number() + 1;
2332 next = get_region(region_idx);
2333 guarantee(next->region_number() == region_idx, "region number must match");
2334 }
2335 return next;
2336 }
2337
2338 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2339 return _monitoring_support;
2340 }
2341
2342 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
2343 return _complete_mark_bit_map;
2344 }
2345
2346 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
2347 return _next_mark_bit_map;
2348 }
2349
2350 address ShenandoahHeap::in_cset_fast_test_addr() {
2351 ShenandoahHeap* heap = ShenandoahHeap::heap();
2352 assert(heap->collection_set() != NULL, "Sanity");
2353 return (address) heap->collection_set()->biased_map_address();
2354 }
2355
2356 address ShenandoahHeap::cancelled_gc_addr() {
2357 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2358 }
2359
2360 address ShenandoahHeap::gc_state_addr() {
2361 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2362 }
2363
2364 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2365 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2366 }
2367
2368 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2369 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2370 }
2371
2372 ShenandoahPacer* ShenandoahHeap::pacer() const {
2373 assert (_pacer != NULL, "sanity");
2374 return _pacer;
2375 }
2376
2377 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2378 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2379 _next_top_at_mark_starts[index] = addr;
2380 }
2381
2382 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2383 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2384 return _next_top_at_mark_starts[index];
2385 }
2386
2387 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2388 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2389 _complete_top_at_mark_starts[index] = addr;
2390 }
2391
2392 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2393 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2394 return _complete_top_at_mark_starts[index];
2395 }
2396
2397 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2398 _degenerated_gc_in_progress.set_cond(in_progress);
2399 }
2400
2401 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2402 _full_gc_in_progress.set_cond(in_progress);
2403 }
2404
2405 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2406 assert (is_full_gc_in_progress(), "should be");
2407 _full_gc_move_in_progress.set_cond(in_progress);
2408 }
2409
2410 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2411 set_gc_state_mask(UPDATEREFS, in_progress);
2412 }
2413
2414 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2415 ShenandoahCodeRoots::add_nmethod(nm);
2416 }
2417
2418 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2419 ShenandoahCodeRoots::remove_nmethod(nm);
2420 }
2421
2422 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2423 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2424 ShenandoahHeapLocker locker(lock());
2425 heap_region_containing(o)->make_pinned();
2426 return o;
2427 }
2428
2429 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2430 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2431 ShenandoahHeapLocker locker(lock());
2432 heap_region_containing(o)->make_unpinned();
2433 }
2434
2435 GCTimer* ShenandoahHeap::gc_timer() const {
2436 return _gc_timer;
2437 }
2438
2439 #ifdef ASSERT
2440 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2441 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2442
2443 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2444 if (UseDynamicNumberOfGCThreads ||
2445 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2446 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2447 } else {
2448 // Use ParallelGCThreads inside safepoints
2449 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2450 }
2451 } else {
2452 if (UseDynamicNumberOfGCThreads ||
2453 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2454 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2455 } else {
2456 // Use ConcGCThreads outside safepoints
2457 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2458 }
2459 }
2460 }
2461 #endif
2462
2463 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
2464 return _connection_matrix;
2465 }
2466
2467 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2468 return _traversal_gc;
2469 }
2470
2471 ShenandoahVerifier* ShenandoahHeap::verifier() {
2472 guarantee(ShenandoahVerify, "Should be enabled");
2473 assert (_verifier != NULL, "sanity");
2474 return _verifier;
2475 }
2476
2477 template<class T>
2478 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2479 private:
2480 T cl;
2481 ShenandoahHeap* _heap;
2482 ShenandoahRegionIterator* _regions;
2483 bool _concurrent;
2484 public:
2485 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2486 AbstractGangTask("Concurrent Update References Task"),
2487 cl(T()),
2488 _heap(ShenandoahHeap::heap()),
2489 _regions(regions),
2490 _concurrent(concurrent) {
2491 }
2492
2493 void work(uint worker_id) {
2494 ShenandoahWorkerSession worker_session(worker_id);
2495 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2496 ShenandoahHeapRegion* r = _regions->next();
2497 while (r != NULL) {
2498 if (_heap->in_collection_set(r)) {
2499 HeapWord* bottom = r->bottom();
2500 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2501 if (top > bottom) {
2502 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2503 }
2504 } else {
2505 if (r->is_active()) {
2506 _heap->marked_object_oop_safe_iterate(r, &cl);
2507 }
2508 }
2509 if (ShenandoahPacing) {
2510 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2511 assert (top_at_start_ur >= r->bottom(), "sanity");
2512 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2513 }
2514 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2515 return;
2516 }
2517 r = _regions->next();
2518 }
2519 }
2520 };
2521
2522 void ShenandoahHeap::update_heap_references(bool concurrent) {
2523 if (UseShenandoahMatrix) {
2524 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(&_update_refs_iterator, concurrent);
2525 workers()->run_task(&task);
2526 } else {
2527 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2528 workers()->run_task(&task);
2529 }
2530 }
2531
2532 void ShenandoahHeap::op_init_updaterefs() {
2533 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2534
2535 set_evacuation_in_progress(false);
2536
2537 retire_and_reset_gclabs();
2538
2539 if (ShenandoahVerify) {
2540 verifier()->verify_before_updaterefs();
2541 }
2542
2543 set_update_refs_in_progress(true);
2544 make_parsable(true);
2545 if (UseShenandoahMatrix) {
2546 connection_matrix()->clear_all();
2547 }
2548 for (uint i = 0; i < num_regions(); i++) {
2549 ShenandoahHeapRegion* r = get_region(i);
2550 r->set_concurrent_iteration_safe_limit(r->top());
2551 }
2552
2553 // Reset iterator.
2554 _update_refs_iterator.reset();
2555
2556 if (ShenandoahPacing) {
2557 pacer()->setup_for_updaterefs();
2558 }
2559 }
2560
2561 void ShenandoahHeap::op_final_updaterefs() {
2562 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2563
2564 // Check if there is left-over work, and finish it
2565 if (_update_refs_iterator.has_next()) {
2566 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2567
2568 // Finish updating references where we left off.
2569 clear_cancelled_gc();
2570 update_heap_references(false);
2571 }
2572
2573 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2574 // everything. On degenerated paths, cancelled gc would not be set anyway.
2575 if (cancelled_gc()) {
2576 clear_cancelled_gc();
2577 }
2578 assert(!cancelled_gc(), "Should have been done right before");
2579
2580 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2581
2582 // Allocations might have happened before we STWed here, record peak:
2583 heuristics()->record_peak_occupancy();
2584
2585 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2586
2587 trash_cset_regions();
2588 set_has_forwarded_objects(false);
2589 set_update_refs_in_progress(false);
2590
2591 if (ShenandoahVerify) {
2592 verifier()->verify_after_updaterefs();
2593 }
2594
2595 {
2596 ShenandoahHeapLocker locker(lock());
2597 _free_set->rebuild();
2598 }
2599 }
2600
2601 void ShenandoahHeap::set_alloc_seq_gc_start() {
2602 // Take next number, the start seq number is inclusive
2603 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2604 }
2605
2606 void ShenandoahHeap::set_alloc_seq_gc_end() {
2607 // Take current number, the end seq number is also inclusive
2608 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2609 }
2610
2611
2612 #ifdef ASSERT
2613 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2614 _lock.assert_owned_by_current_thread();
2615 }
2616
2617 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2618 _lock.assert_not_owned_by_current_thread();
2619 }
2620
2621 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2622 _lock.assert_owned_by_current_thread_or_safepoint();
2623 }
2624 #endif
2625
2626 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2627 print_on(st);
2628 print_heap_regions_on(st);
2629 }
2630
2631 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2632 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2633
2634 size_t regions_from = _bitmap_regions_per_slice * slice;
2635 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2636 for (size_t g = regions_from; g < regions_to; g++) {
2637 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2638 if (skip_self && g == r->region_number()) continue;
2639 if (get_region(g)->is_committed()) {
2640 return true;
2641 }
2642 }
2643 return false;
2644 }
2645
2646 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2647 assert_heaplock_owned_by_current_thread();
2648
2649 if (is_bitmap_slice_committed(r, true)) {
2650 // Some other region from the group is already committed, meaning the bitmap
2651 // slice is already committed, we exit right away.
2652 return true;
2653 }
2654
2655 // Commit the bitmap slice:
2656 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2657 size_t off = _bitmap_bytes_per_slice * slice;
2658 size_t len = _bitmap_bytes_per_slice;
2659 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2660 return false;
2661 }
2662 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2663 return false;
2664 }
2665 return true;
2666 }
2667
2668 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2669 assert_heaplock_owned_by_current_thread();
2670
2671 if (is_bitmap_slice_committed(r, true)) {
2672 // Some other region from the group is still committed, meaning the bitmap
2673 // slice is should stay committed, exit right away.
2674 return true;
2675 }
2676
2677 // Uncommit the bitmap slice:
2678 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2679 size_t off = _bitmap_bytes_per_slice * slice;
2680 size_t len = _bitmap_bytes_per_slice;
2681 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2682 return false;
2683 }
2684 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2685 return false;
2686 }
2687 return true;
2688 }
2689
2690 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2691 assert_heaplock_owned_by_current_thread();
2692 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2693
2694 if (is_bitmap_slice_committed(r, true)) {
2695 // Some other region from the group is still committed, meaning the bitmap
2696 // slice is should stay committed, exit right away.
2697 return true;
2698 }
2699
2700 // Idle the bitmap slice:
2701 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2702 size_t off = _bitmap_bytes_per_slice * slice;
2703 size_t len = _bitmap_bytes_per_slice;
2704 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2705 return false;
2706 }
2707 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2708 return false;
2709 }
2710 return true;
2711 }
2712
2713 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2714 assert_heaplock_owned_by_current_thread();
2715 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2716 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2717 size_t off = _bitmap_bytes_per_slice * slice;
2718 size_t len = _bitmap_bytes_per_slice;
2719 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2720 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2721 }
2722
2723 void ShenandoahHeap::safepoint_synchronize_begin() {
2724 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2725 SuspendibleThreadSet::synchronize();
2726 }
2727 }
2728
2729 void ShenandoahHeap::safepoint_synchronize_end() {
2730 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2731 SuspendibleThreadSet::desynchronize();
2732 }
2733 }
2734
2735 void ShenandoahHeap::vmop_entry_init_mark() {
2736 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2737 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2738 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2739
2740 try_inject_alloc_failure();
2741 VM_ShenandoahInitMark op;
2742 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2743 }
2744
2745 void ShenandoahHeap::vmop_entry_final_mark() {
2746 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2747 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2748 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2749
2750 try_inject_alloc_failure();
2751 VM_ShenandoahFinalMarkStartEvac op;
2752 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2753 }
2754
2755 void ShenandoahHeap::vmop_entry_final_evac() {
2756 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2757 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2758 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2759
2760 VM_ShenandoahFinalEvac op;
2761 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2762 }
2763
2764 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2765 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2766 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2767 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2768
2769 try_inject_alloc_failure();
2770 VM_ShenandoahInitUpdateRefs op;
2771 VMThread::execute(&op);
2772 }
2773
2774 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2775 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2776 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2777 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2778
2779 try_inject_alloc_failure();
2780 VM_ShenandoahFinalUpdateRefs op;
2781 VMThread::execute(&op);
2782 }
2783
2784 void ShenandoahHeap::vmop_entry_init_traversal() {
2785 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2786 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2787 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2788
2789 try_inject_alloc_failure();
2790 VM_ShenandoahInitTraversalGC op;
2791 VMThread::execute(&op);
2792 }
2793
2794 void ShenandoahHeap::vmop_entry_final_traversal() {
2795 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2796 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2797 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2798
2799 try_inject_alloc_failure();
2800 VM_ShenandoahFinalTraversalGC op;
2801 VMThread::execute(&op);
2802 }
2803
2804 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2805 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2806 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2807 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2808
2809 try_inject_alloc_failure();
2810 VM_ShenandoahFullGC op(cause);
2811 VMThread::execute(&op);
2812 }
2813
2814 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2815 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2816 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2817 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2818
2819 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2820 VMThread::execute(°enerated_gc);
2821 }
2822
2823 void ShenandoahHeap::entry_init_mark() {
2824 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2825 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2826
2827 FormatBuffer<> msg("Pause Init Mark%s%s%s",
2828 has_forwarded_objects() ? " (update refs)" : "",
2829 process_references() ? " (process refs)" : "",
2830 unload_classes() ? " (unload classes)" : "");
2831 GCTraceTime(Info, gc) time(msg, gc_timer());
2832 EventMark em("%s", msg.buffer());
2833
2834 ShenandoahWorkerScope scope(workers(),
2835 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2836 "init marking");
2837
2838 op_init_mark();
2839 }
2840
2841 void ShenandoahHeap::entry_final_mark() {
2842 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2843 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2844
2845 FormatBuffer<> msg("Pause Final Mark%s%s%s",
2846 has_forwarded_objects() ? " (update refs)" : "",
2847 process_references() ? " (process refs)" : "",
2848 unload_classes() ? " (unload classes)" : "");
2849 GCTraceTime(Info, gc) time(msg, gc_timer());
2850 EventMark em("%s", msg.buffer());
2851
2852 ShenandoahWorkerScope scope(workers(),
2853 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2854 "final marking");
2855
2856 op_final_mark();
2857 }
2858
2859 void ShenandoahHeap::entry_final_evac() {
2860 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2861 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2862
2863 FormatBuffer<> msg("Pause Final Evac");
2864 GCTraceTime(Info, gc) time(msg, gc_timer());
2865 EventMark em("%s", msg.buffer());
2866
2867 op_final_evac();
2868 }
2869
2870 void ShenandoahHeap::entry_init_updaterefs() {
2871 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2872 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2873
2874 static const char* msg = "Pause Init Update Refs";
2875 GCTraceTime(Info, gc) time(msg, gc_timer());
2876 EventMark em("%s", msg);
2877
2878 // No workers used in this phase, no setup required
2879
2880 op_init_updaterefs();
2881 }
2882
2883 void ShenandoahHeap::entry_final_updaterefs() {
2884 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2885 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2886
2887 static const char* msg = "Pause Final Update Refs";
2888 GCTraceTime(Info, gc) time(msg, gc_timer());
2889 EventMark em("%s", msg);
2890
2891 ShenandoahWorkerScope scope(workers(),
2892 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2893 "final reference update");
2894
2895 op_final_updaterefs();
2896 }
2897
2898 void ShenandoahHeap::entry_init_traversal() {
2899 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2900 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2901
2902 static const char* msg = "Pause Init Traversal";
2903 GCTraceTime(Info, gc) time(msg, gc_timer());
2904 EventMark em("%s", msg);
2905
2906 ShenandoahWorkerScope scope(workers(),
2907 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2908 "init traversal");
2909
2910 op_init_traversal();
2911 }
2912
2913 void ShenandoahHeap::entry_final_traversal() {
2914 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2915 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2916
2917 static const char* msg = "Pause Final Traversal";
2918 GCTraceTime(Info, gc) time(msg, gc_timer());
2919 EventMark em("%s", msg);
2920
2921 ShenandoahWorkerScope scope(workers(),
2922 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2923 "final traversal");
2924
2925 op_final_traversal();
2926 }
2927
2928 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2929 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2930 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2931
2932 static const char* msg = "Pause Full";
2933 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2934 EventMark em("%s", msg);
2935
2936 ShenandoahWorkerScope scope(workers(),
2937 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2938 "full gc");
2939
2940 op_full(cause);
2941 }
2942
2943 void ShenandoahHeap::entry_degenerated(int point) {
2944 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2945 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2946
2947 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2948 FormatBuffer<> msg("Pause Degenerated GC (%s)", degen_point_to_string(dpoint));
2949 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2950 EventMark em("%s", msg.buffer());
2951
2952 ShenandoahWorkerScope scope(workers(),
2953 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2954 "stw degenerated gc");
2955
2956 set_degenerated_gc_in_progress(true);
2957 op_degenerated(dpoint);
2958 set_degenerated_gc_in_progress(false);
2959 }
2960
2961 void ShenandoahHeap::entry_mark() {
2962 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2963
2964 FormatBuffer<> msg("Concurrent marking%s%s%s",
2965 has_forwarded_objects() ? " (update refs)" : "",
2966 process_references() ? " (process refs)" : "",
2967 unload_classes() ? " (unload classes)" : "");
2968 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2969 EventMark em("%s", msg.buffer());
2970
2971 ShenandoahWorkerScope scope(workers(),
2972 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2973 "concurrent marking");
2974
2975 try_inject_alloc_failure();
2976 op_mark();
2977 }
2978
2979 void ShenandoahHeap::entry_evac() {
2980 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2981 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2982
2983 static const char* msg = "Concurrent evacuation";
2984 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2985 EventMark em("%s", msg);
2986
2987 ShenandoahWorkerScope scope(workers(),
2988 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2989 "concurrent evacuation");
2990
2991 try_inject_alloc_failure();
2992 op_evac();
2993 }
2994
2995 void ShenandoahHeap::entry_updaterefs() {
2996 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2997
2998 static const char* msg = "Concurrent update references";
2999 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3000 EventMark em("%s", msg);
3001
3002 ShenandoahWorkerScope scope(workers(),
3003 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
3004 "concurrent reference update");
3005
3006 try_inject_alloc_failure();
3007 op_updaterefs();
3008 }
3009 void ShenandoahHeap::entry_cleanup() {
3010 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
3011
3012 static const char* msg = "Concurrent cleanup";
3013 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3014 EventMark em("%s", msg);
3015
3016 // This phase does not use workers, no need for setup
3017
3018 try_inject_alloc_failure();
3019 op_cleanup();
3020 }
3021
3022 void ShenandoahHeap::entry_cleanup_traversal() {
3023 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
3024
3025 static const char* msg = "Concurrent cleanup";
3026 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3027 EventMark em("%s", msg);
3028
3029 ShenandoahWorkerScope scope(workers(),
3030 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
3031 "concurrent traversal cleanup");
3032
3033 try_inject_alloc_failure();
3034 op_cleanup_traversal();
3035 }
3036
3037 void ShenandoahHeap::entry_cleanup_bitmaps() {
3038 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
3039
3040 static const char* msg = "Concurrent cleanup";
3041 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3042 EventMark em("%s", msg);
3043
3044 ShenandoahWorkerScope scope(workers(),
3045 ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup(),
3046 "concurrent cleanup");
3047
3048 try_inject_alloc_failure();
3049 op_cleanup_bitmaps();
3050 }
3051
3052 void ShenandoahHeap::entry_preclean() {
3053 if (ShenandoahPreclean && process_references()) {
3054 static const char* msg = "Concurrent precleaning";
3055 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3056 EventMark em("%s", msg);
3057
3058 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
3059
3060 ShenandoahWorkerScope scope(workers(),
3061 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
3062 "concurrent preclean");
3063
3064 try_inject_alloc_failure();
3065 op_preclean();
3066 }
3067 }
3068
3069 void ShenandoahHeap::entry_traversal() {
3070 static const char* msg = "Concurrent traversal";
3071 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3072 EventMark em("%s", msg);
3073
3074 TraceCollectorStats tcs(is_minor_gc() ? monitoring_support()->partial_collection_counters()
3075 : monitoring_support()->concurrent_collection_counters());
3076
3077 ShenandoahWorkerScope scope(workers(),
3078 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
3079 "concurrent traversal");
3080
3081 try_inject_alloc_failure();
3082 op_traversal();
3083 }
3084
3085 void ShenandoahHeap::entry_uncommit(double shrink_before) {
3086 static const char *msg = "Concurrent uncommit";
3087 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
3088 EventMark em("%s", msg);
3089
3090 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
3091
3092 op_uncommit(shrink_before);
3093 }
3094
3095 void ShenandoahHeap::try_inject_alloc_failure() {
3096 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
3097 _inject_alloc_failure.set();
3098 os::naked_short_sleep(1);
3099 if (cancelled_gc()) {
3100 log_info(gc)("Allocation failure was successfully injected");
3101 }
3102 }
3103 }
3104
3105 bool ShenandoahHeap::should_inject_alloc_failure() {
3106 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
3107 }
3108
3109 void ShenandoahHeap::initialize_serviceability() {
3110 _memory_pool = new ShenandoahMemoryPool(this);
3111 _cycle_memory_manager.add_pool(_memory_pool);
3112 _stw_memory_manager.add_pool(_memory_pool);
3113 }
3114
3115 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
3116 GrowableArray<GCMemoryManager*> memory_managers(2);
3117 memory_managers.append(&_cycle_memory_manager);
3118 memory_managers.append(&_stw_memory_manager);
3119 return memory_managers;
3120 }
3121
3122 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
3123 GrowableArray<MemoryPool*> memory_pools(1);
3124 memory_pools.append(_memory_pool);
3125 return memory_pools;
3126 }
3127
3128 void ShenandoahHeap::enter_evacuation() {
3129 _oom_evac_handler.enter_evacuation();
3130 }
3131
3132 void ShenandoahHeap::leave_evacuation() {
3133 _oom_evac_handler.leave_evacuation();
3134 }
3135
3136 SoftRefPolicy* ShenandoahHeap::soft_ref_policy() {
3137 return &_soft_ref_policy;
3138 }
3139
3140 ShenandoahRegionIterator::ShenandoahRegionIterator() :
3141 _index(0),
3142 _heap(ShenandoahHeap::heap()) {}
3143
3144 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
3145 _index(0),
3146 _heap(heap) {}
3147
3148 void ShenandoahRegionIterator::reset() {
3149 _index = 0;
3150 }
3151
3152 bool ShenandoahRegionIterator::has_next() const {
3153 return _index < _heap->num_regions();
3154 }
3155
3156 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
3157 ShenandoahRegionIterator regions;
3158 ShenandoahHeapRegion* r = regions.next();
3159 while (r != NULL) {
3160 if (cl.heap_region_do(r)) {
3161 break;
3162 }
3163 r = regions.next();
3164 }
3165 }
3166
3167 bool ShenandoahHeap::is_minor_gc() const {
3168 return _gc_cycle_mode.get() == MINOR;
3169 }
3170
3171 bool ShenandoahHeap::is_major_gc() const {
3172 return _gc_cycle_mode.get() == MAJOR;
3173 }
3174
3175 void ShenandoahHeap::set_cycle_mode(GCCycleMode gc_cycle_mode) {
3176 _gc_cycle_mode.set(gc_cycle_mode);
3177 }
3178
3179 char ShenandoahHeap::gc_state() const {
3180 return _gc_state.raw_value();
3181 }
3182
3183 void ShenandoahHeap::deduplicate_string(oop str) {
3184 assert(java_lang_String::is_instance(str), "invariant");
3185
3186 if (ShenandoahStringDedup::is_enabled()) {
3187 ShenandoahStringDedup::deduplicate(str);
3188 }
3189 }