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/parallelCleaning.hpp"
30 #include "gc/shared/plab.hpp"
31
32 #include "gc/shenandoah/brooksPointer.hpp"
33 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
34 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
36 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
39 #include "gc/shenandoah/shenandoahControlThread.hpp"
40 #include "gc/shenandoah/shenandoahFreeSet.hpp"
41 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
42 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
44 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
45 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
46 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
47 #include "gc/shenandoah/shenandoahMetrics.hpp"
48 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
49 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
50 #include "gc/shenandoah/shenandoahPacer.hpp"
51 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
52 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
53 #include "gc/shenandoah/shenandoahStringDedup.hpp"
54 #include "gc/shenandoah/shenandoahUtils.hpp"
55 #include "gc/shenandoah/shenandoahVerifier.hpp"
56 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
57 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
58 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
59 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
60 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
61 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
62 #include "gc/shenandoah/heuristics/shenandoahPartialConnectedHeuristics.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahPartialGenerationalHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahPartialLRUHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
67
68 #include "memory/metaspace.hpp"
69 #include "runtime/vmThread.hpp"
70 #include "services/mallocTracker.hpp"
71
72 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
73
74 #ifdef ASSERT
75 template <class T>
76 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
77 T o = RawAccess<>::oop_load(p);
78 if (! CompressedOops::is_null(o)) {
79 oop obj = CompressedOops::decode_not_null(o);
80 shenandoah_assert_not_forwarded(p, obj);
81 }
82 }
83
84 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
85 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
86 #endif
87
88 const char* ShenandoahHeap::name() const {
89 return "Shenandoah";
90 }
91
92 class ShenandoahPretouchTask : public AbstractGangTask {
93 private:
94 ShenandoahRegionIterator _regions;
95 const size_t _bitmap_size;
96 const size_t _page_size;
97 char* _bitmap0_base;
98 char* _bitmap1_base;
99 public:
100 ShenandoahPretouchTask(char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
101 size_t page_size) :
102 AbstractGangTask("Shenandoah PreTouch"),
103 _bitmap0_base(bitmap0_base),
104 _bitmap1_base(bitmap1_base),
105 _bitmap_size(bitmap_size),
106 _page_size(page_size) {}
107
108 virtual void work(uint worker_id) {
109 ShenandoahHeapRegion* r = _regions.next();
110 while (r != NULL) {
111 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
112 r->region_number(), p2i(r->bottom()), p2i(r->end()));
113 os::pretouch_memory(r->bottom(), r->end(), _page_size);
114
115 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
116 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
117 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
118
119 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
120 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
121 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
122
123 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
124 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
125 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
126
127 r = _regions.next();
128 }
129 }
130 };
131
132 jint ShenandoahHeap::initialize() {
133
134 BrooksPointer::initial_checks();
135
136 initialize_heuristics();
137
138 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
139 size_t max_byte_size = collector_policy()->max_heap_byte_size();
140 size_t heap_alignment = collector_policy()->heap_alignment();
141
142 if (ShenandoahAlwaysPreTouch) {
143 // Enabled pre-touch means the entire heap is committed right away.
144 init_byte_size = max_byte_size;
145 }
146
147 Universe::check_alignment(max_byte_size,
148 ShenandoahHeapRegion::region_size_bytes(),
149 "shenandoah heap");
150 Universe::check_alignment(init_byte_size,
151 ShenandoahHeapRegion::region_size_bytes(),
152 "shenandoah heap");
153
154 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
155 heap_alignment);
156 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
157
158 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
159 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
160
161 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
162 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
163 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
164 _committed = _initial_size;
165
166 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
167 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
168 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
169 }
170
171 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
172 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
173
174 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
175 _free_set = new ShenandoahFreeSet(this, _num_regions);
176
177 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
178
179 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
180 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
181 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
182
183 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
184 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
185 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
186
187 if (ShenandoahPacing) {
188 _pacer = new ShenandoahPacer(this);
189 _pacer->setup_for_idle();
190 } else {
191 _pacer = NULL;
192 }
193
194 {
195 ShenandoahHeapLocker locker(lock());
196 for (size_t i = 0; i < _num_regions; i++) {
197 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
198 (HeapWord*) pgc_rs.base() + reg_size_words * i,
199 reg_size_words,
200 i,
201 i < num_committed_regions);
202
203 _complete_top_at_mark_starts_base[i] = r->bottom();
204 _next_top_at_mark_starts_base[i] = r->bottom();
205 _regions[i] = r;
206 assert(!collection_set()->is_in(i), "New region should not be in collection set");
207 }
208
209 _free_set->rebuild();
210 }
211
212 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
213 "misaligned heap: "PTR_FORMAT, p2i(base()));
214
215 // The call below uses stuff (the SATB* things) that are in G1, but probably
216 // belong into a shared location.
217 ShenandoahBarrierSet::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
218 SATB_Q_FL_lock,
219 20 /*G1SATBProcessCompletedThreshold */,
220 Shared_SATB_Q_lock);
221
222 // Reserve space for prev and next bitmap.
223 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
224 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
225 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
226 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
227
228 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
229
230 guarantee(bitmap_bytes_per_region != 0,
231 "Bitmap bytes per region should not be zero");
232 guarantee(is_power_of_2(bitmap_bytes_per_region),
233 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
234
235 if (bitmap_page_size > bitmap_bytes_per_region) {
236 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
237 _bitmap_bytes_per_slice = bitmap_page_size;
238 } else {
239 _bitmap_regions_per_slice = 1;
240 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
241 }
242
243 guarantee(_bitmap_regions_per_slice >= 1,
244 "Should have at least one region per slice: " SIZE_FORMAT,
245 _bitmap_regions_per_slice);
246
247 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
248 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
249 _bitmap_bytes_per_slice, bitmap_page_size);
250
251 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
252 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
253 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
254
255 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
256 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
257 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
258
259 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
260 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
261 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
262 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
263 "couldn't allocate initial bitmap");
264 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
265 "couldn't allocate initial bitmap");
266
267 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
268
269 if (ShenandoahVerify) {
270 ReservedSpace verify_bitmap(_bitmap_size, page_size);
271 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
272 "couldn't allocate verification bitmap");
273 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
274 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
275 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
276 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
277 }
278
279 if (ShenandoahAlwaysPreTouch) {
280 assert (!AlwaysPreTouch, "Should have been overridden");
281
282 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
283 // before initialize() below zeroes it with initializing thread. For any given region,
284 // we touch the region and the corresponding bitmaps from the same thread.
285 ShenandoahWorkerScope scope(workers(), _max_workers);
286
287 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
288 _num_regions, page_size);
289 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
290 _workers->run_task(&cl);
291 }
292
293 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
294 _complete_mark_bit_map = &_mark_bit_map0;
295
296 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
297 _next_mark_bit_map = &_mark_bit_map1;
298
299 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
300 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
301 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
302 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
303 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
304
305 if (UseShenandoahMatrix) {
306 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
307 } else {
308 _connection_matrix = NULL;
309 }
310
311 _traversal_gc = heuristics()->can_do_traversal_gc() ?
312 new ShenandoahTraversalGC(this, _num_regions) :
313 NULL;
314
315 _monitoring_support = new ShenandoahMonitoringSupport(this);
316
317 _phase_timings = new ShenandoahPhaseTimings();
318
319 if (ShenandoahAllocationTrace) {
320 _alloc_tracker = new ShenandoahAllocTracker();
321 }
322
323 ShenandoahStringDedup::initialize();
324
325 _control_thread = new ShenandoahControlThread();
326
327 ShenandoahCodeRoots::initialize();
328
329 LogTarget(Trace, gc, region) lt;
330 if (lt.is_enabled()) {
331 ResourceMark rm;
332 LogStream ls(lt);
333 log_trace(gc, region)("All Regions");
334 print_heap_regions_on(&ls);
335 log_trace(gc, region)("Free Regions");
336 _free_set->print_on(&ls);
337 }
338
339 log_info(gc, init)("Safepointing mechanism: %s",
340 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
341 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
342
343 return JNI_OK;
344 }
345
346 void ShenandoahHeap::initialize_heuristics() {
347 if (ShenandoahGCHeuristics != NULL) {
348 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
349 _heuristics = new ShenandoahAggressiveHeuristics();
350 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
351 _heuristics = new ShenandoahStaticHeuristics();
352 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
353 _heuristics = new ShenandoahAdaptiveHeuristics();
354 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
355 _heuristics = new ShenandoahPassiveHeuristics();
356 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
357 _heuristics = new ShenandoahCompactHeuristics();
358 } else if (strcmp(ShenandoahGCHeuristics, "connected") == 0) {
359 _heuristics = new ShenandoahPartialConnectedHeuristics();
360 } else if (strcmp(ShenandoahGCHeuristics, "generational") == 0) {
361 _heuristics = new ShenandoahPartialGenerationalHeuristics();
362 } else if (strcmp(ShenandoahGCHeuristics, "LRU") == 0) {
363 _heuristics = new ShenandoahPartialLRUHeuristics();
364 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
365 _heuristics = new ShenandoahTraversalHeuristics();
366 } else {
367 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
368 }
369
370 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
371 vm_exit_during_initialization(
372 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
373 _heuristics->name()));
374 }
375 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
376 vm_exit_during_initialization(
377 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
378 _heuristics->name()));
379 }
380
381 if (ShenandoahStoreValEnqueueBarrier && ShenandoahStoreValReadBarrier) {
382 vm_exit_during_initialization("Cannot use both ShenandoahStoreValEnqueueBarrier and ShenandoahStoreValReadBarrier");
383 }
384 log_info(gc, init)("Shenandoah heuristics: %s",
385 _heuristics->name());
386 _heuristics->print_thresholds();
387 } else {
388 ShouldNotReachHere();
389 }
390
391 }
392
393 #ifdef _MSC_VER
394 #pragma warning( push )
395 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
396 #endif
397
398 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
399 CollectedHeap(),
400 _shenandoah_policy(policy),
401 _soft_ref_policy(),
402 _regions(NULL),
403 _free_set(NULL),
404 _collection_set(NULL),
405 _update_refs_iterator(this),
406 _bytes_allocated_since_gc_start(0),
407 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
408 _ref_processor(NULL),
409 _next_top_at_mark_starts(NULL),
410 _next_top_at_mark_starts_base(NULL),
411 _complete_top_at_mark_starts(NULL),
412 _complete_top_at_mark_starts_base(NULL),
413 _mark_bit_map0(),
414 _mark_bit_map1(),
415 _aux_bit_map(),
416 _connection_matrix(NULL),
417 _verifier(NULL),
418 _pacer(NULL),
419 _used_at_last_gc(0),
420 _alloc_seq_at_last_gc_start(0),
421 _alloc_seq_at_last_gc_end(0),
422 _safepoint_workers(NULL),
423 _gc_cycle_mode(),
424 #ifdef ASSERT
425 _heap_expansion_count(0),
426 #endif
427 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
428 _phase_timings(NULL),
429 _alloc_tracker(NULL),
430 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
431 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
432 _mutator_gclab_stats(new PLABStats("Shenandoah mutator GCLAB stats", OldPLABSize, PLABWeight)),
433 _collector_gclab_stats(new PLABStats("Shenandoah collector GCLAB stats", YoungPLABSize, PLABWeight)),
434 _memory_pool(NULL)
435 {
436 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
437 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
438 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
439
440 _scm = new ShenandoahConcurrentMark();
441 _full_gc = new ShenandoahMarkCompact();
442 _used = 0;
443
444 _max_workers = MAX2(_max_workers, 1U);
445 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
446 /* are_GC_task_threads */true,
447 /* are_ConcurrentGC_threads */false);
448 if (_workers == NULL) {
449 vm_exit_during_initialization("Failed necessary allocation.");
450 } else {
451 _workers->initialize_workers();
452 }
453
454 if (ParallelSafepointCleanupThreads > 1) {
455 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
456 ParallelSafepointCleanupThreads,
457 false, false);
458 _safepoint_workers->initialize_workers();
459 }
460 }
461
462 #ifdef _MSC_VER
463 #pragma warning( pop )
464 #endif
465
466 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
467 private:
468 ShenandoahRegionIterator _regions;
469
470 public:
471 ShenandoahResetNextBitmapTask() :
472 AbstractGangTask("Parallel Reset Bitmap Task") {}
473
474 void work(uint worker_id) {
475 ShenandoahHeapRegion* region = _regions.next();
476 ShenandoahHeap* heap = ShenandoahHeap::heap();
477 while (region != NULL) {
478 if (heap->is_bitmap_slice_committed(region)) {
479 HeapWord* bottom = region->bottom();
480 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
481 if (top > bottom) {
482 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
483 }
484 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
485 }
486 region = _regions.next();
487 }
488 }
489 };
490
491 void ShenandoahHeap::reset_next_mark_bitmap() {
492 assert_gc_workers(_workers->active_workers());
493
494 ShenandoahResetNextBitmapTask task;
495 _workers->run_task(&task);
496 }
497
498 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
499 private:
500 ShenandoahRegionIterator _regions;
501
502 public:
503 ShenandoahResetNextBitmapTraversalTask() :
504 AbstractGangTask("Parallel Reset Bitmap Task for Traversal") {}
505
506 void work(uint worker_id) {
507 ShenandoahHeap* heap = ShenandoahHeap::heap();
508 ShenandoahHeapRegionSet* traversal_set = heap->traversal_gc()->traversal_set();
509 ShenandoahHeapRegion* region = _regions.next();
510 while (region != NULL) {
511 if (heap->is_bitmap_slice_committed(region)) {
512 if (traversal_set->is_in(region) && !region->is_trash()) {
513 ShenandoahHeapLocker locker(heap->lock());
514 HeapWord* bottom = region->bottom();
515 HeapWord* top = heap->next_top_at_mark_start(bottom);
516 assert(top <= region->top(),
517 "TAMS must smaller/equals than top: TAMS: "PTR_FORMAT", top: "PTR_FORMAT,
518 p2i(top), p2i(region->top()));
519 if (top > bottom) {
520 heap->complete_mark_bit_map()->copy_from(heap->next_mark_bit_map(), MemRegion(bottom, top));
521 heap->set_complete_top_at_mark_start(bottom, top);
522 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
523 heap->set_next_top_at_mark_start(bottom, bottom);
524 }
525 }
526 assert(heap->is_next_bitmap_clear_range(region->bottom(), region->end()),
527 "need clear next bitmap");
528 }
529 region = _regions.next();
530 }
531 }
532 };
533
534 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
535 assert_gc_workers(_workers->active_workers());
536
537 ShenandoahResetNextBitmapTraversalTask task;
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::handle_heap_shrinkage(double shrink_before) {
717 if (!ShenandoahUncommit) {
718 return;
719 }
720
721 ShenandoahHeapLocker locker(lock());
722
723 size_t count = 0;
724 for (size_t i = 0; i < num_regions(); i++) {
725 ShenandoahHeapRegion* r = get_region(i);
726 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
727 r->make_uncommitted();
728 count++;
729 }
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
739 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
740 // Retain tlab and allocate object in shared space if
741 // the amount free in the tlab is too large to discard.
742 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
743
744 // Discard gclab and allocate a new one.
745 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
746 gclab->retire();
747 // Figure out size of new GCLAB
748 size_t new_gclab_size;
749 if (thread->is_Java_thread()) {
750 new_gclab_size = _mutator_gclab_stats->desired_plab_sz(Threads::number_of_threads());
751 } else {
752 new_gclab_size = _collector_gclab_stats->desired_plab_sz(workers()->active_workers());
753 }
754
755 // Allocate a new GCLAB...
756 HeapWord* gclab_buf = allocate_new_gclab(new_gclab_size);
757 if (gclab_buf == NULL) {
758 return NULL;
759 }
760
761 if (ZeroTLAB) {
762 // ..and clear it.
763 Copy::zero_to_words(gclab_buf, new_gclab_size);
764 } else {
765 // ...and zap just allocated object.
766 #ifdef ASSERT
767 // Skip mangling the space corresponding to the object header to
768 // ensure that the returned space is not considered parsable by
769 // any concurrent GC thread.
770 size_t hdr_size = oopDesc::header_size();
771 Copy::fill_to_words(gclab_buf + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
772 #endif // ASSERT
773 }
774 gclab->set_buf(gclab_buf, new_gclab_size);
775 return gclab->allocate(size);
776 }
777
778 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
779 size_t requested_size,
780 size_t* actual_size) {
781 #ifdef ASSERT
782 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", requested_size * HeapWordSize);
783 #endif
784 *actual_size = requested_size;
785 return allocate_new_lab(requested_size, _alloc_tlab);
786 }
787
788 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
789 #ifdef ASSERT
790 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
791 #endif
792 return allocate_new_lab(word_size, _alloc_gclab);
793 }
794
795 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
796 HeapWord* result = allocate_memory(word_size, type);
797
798 if (result != NULL) {
799 assert(! in_collection_set(result), "Never allocate in collection set");
800
801 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
802
803 }
804 return result;
805 }
806
807 ShenandoahHeap* ShenandoahHeap::heap() {
808 CollectedHeap* heap = Universe::heap();
809 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
810 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
811 return (ShenandoahHeap*) heap;
812 }
813
814 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
815 CollectedHeap* heap = Universe::heap();
816 return (ShenandoahHeap*) heap;
817 }
818
819 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
820 ShenandoahAllocTrace trace_alloc(word_size, type);
821
822 bool in_new_region = false;
823 HeapWord* result = NULL;
824
825 if (type == _alloc_tlab || type == _alloc_shared) {
826 if (ShenandoahPacing) {
827 pacer()->pace_for_alloc(word_size);
828 }
829
830 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
831 result = allocate_memory_under_lock(word_size, type, in_new_region);
832 }
833
834 // Allocation failed, block until control thread reacted, then retry allocation.
835 //
836 // It might happen that one of the threads requesting allocation would unblock
837 // way later after GC happened, only to fail the second allocation, because
838 // other threads have already depleted the free storage. In this case, a better
839 // strategy is to try again, as long as GC makes progress.
840 //
841 // Then, we need to make sure the allocation was retried after at least one
842 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
843
844 size_t tries = 0;
845
846 while (result == NULL && last_gc_made_progress()) {
847 tries++;
848 control_thread()->handle_alloc_failure(word_size);
849 result = allocate_memory_under_lock(word_size, type, in_new_region);
850 }
851
852 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
853 tries++;
854 control_thread()->handle_alloc_failure(word_size);
855 result = allocate_memory_under_lock(word_size, type, in_new_region);
856 }
857
858 } else {
859 assert(type == _alloc_gclab || type == _alloc_shared_gc, "Can only accept these types here");
860 result = allocate_memory_under_lock(word_size, type, in_new_region);
861 // Do not call handle_alloc_failure() here, because we cannot block.
862 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
863 }
864
865 if (in_new_region) {
866 control_thread()->notify_heap_changed();
867 }
868
869 if (result != NULL) {
870 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
871 word_size, p2i(result), Thread::current()->osthread()->thread_id());
872 notify_alloc(word_size, false);
873 }
874
875 return result;
876 }
877
878 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
879 ShenandoahHeapLocker locker(lock());
880 return _free_set->allocate(word_size, type, in_new_region);
881 }
882
883 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
884 HeapWord* obj = start + BrooksPointer::word_size();
885 BrooksPointer::initialize(oop(obj));
886 CollectedHeap::fill_with_object(obj, end, zap);
887 }
888
889 HeapWord* ShenandoahHeap::obj_allocate_raw(Klass* klass, size_t size,
890 bool* gc_overhead_limit_was_exceeded, TRAPS) {
891 size += BrooksPointer::word_size();
892 HeapWord* result = CollectedHeap::obj_allocate_raw(klass, size, gc_overhead_limit_was_exceeded, THREAD);
893 if (result != NULL) {
894 result += BrooksPointer::word_size();
895 BrooksPointer::initialize(oop(result));
896 assert(! in_collection_set(result), "never allocate in targetted region");
897 }
898 return result;
899 }
900
901 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
902 bool* gc_overhead_limit_was_exceeded) {
903 return allocate_memory(size, _alloc_shared);
904 }
905
906 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
907 private:
908 ShenandoahHeap* _heap;
909 Thread* _thread;
910 public:
911 ShenandoahEvacuateUpdateRootsClosure() :
912 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
913 }
914
915 private:
916 template <class T>
917 void do_oop_work(T* p) {
918 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
919
920 T o = RawAccess<>::oop_load(p);
921 if (! CompressedOops::is_null(o)) {
922 oop obj = CompressedOops::decode_not_null(o);
923 if (_heap->in_collection_set(obj)) {
924 shenandoah_assert_marked_complete(p, obj);
925 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
926 if (oopDesc::unsafe_equals(resolved, obj)) {
927 resolved = _heap->evacuate_object(obj, _thread);
928 }
929 RawAccess<OOP_NOT_NULL>::oop_store(p, resolved);
930 }
931 }
932 }
933
934 public:
935 void do_oop(oop* p) {
936 do_oop_work(p);
937 }
938 void do_oop(narrowOop* p) {
939 do_oop_work(p);
940 }
941 };
942
943 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
944 private:
945 ShenandoahHeap* _heap;
946 Thread* _thread;
947 public:
948 ShenandoahEvacuateRootsClosure() :
949 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
950 }
951
952 private:
953 template <class T>
954 void do_oop_work(T* p) {
955 T o = RawAccess<>::oop_load(p);
956 if (! CompressedOops::is_null(o)) {
957 oop obj = CompressedOops::decode_not_null(o);
958 if (_heap->in_collection_set(obj)) {
959 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
960 if (oopDesc::unsafe_equals(resolved, obj)) {
961 _heap->evacuate_object(obj, _thread);
962 }
963 }
964 }
965 }
966
967 public:
968 void do_oop(oop* p) {
969 do_oop_work(p);
970 }
971 void do_oop(narrowOop* p) {
972 do_oop_work(p);
973 }
974 };
975
976 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
977 private:
978 ShenandoahHeap* const _heap;
979 Thread* const _thread;
980 public:
981 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
982 _heap(heap), _thread(Thread::current()) {}
983
984 void do_object(oop p) {
985 shenandoah_assert_marked_complete(NULL, p);
986 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
987 _heap->evacuate_object(p, _thread);
988 }
989 }
990 };
991
992 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
993 private:
994 ShenandoahHeap* const _sh;
995 ShenandoahCollectionSet* const _cs;
996 ShenandoahSharedFlag _claimed_codecache;
997
998 public:
999 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
1000 ShenandoahCollectionSet* cs) :
1001 AbstractGangTask("Parallel Evacuation Task"),
1002 _cs(cs),
1003 _sh(sh)
1004 {}
1005
1006 void work(uint worker_id) {
1007
1008 ShenandoahEvacOOMScope oom_evac_scope;
1009 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
1010
1011 // If concurrent code cache evac is enabled, evacuate it here.
1012 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
1013 // nmethods. The update would be handled elsewhere.
1014 if (ShenandoahConcurrentEvacCodeRoots && _claimed_codecache.try_set()) {
1015 ShenandoahEvacuateRootsClosure cl;
1016 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1017 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
1018 CodeCache::blobs_do(&blobs);
1019 }
1020
1021 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
1022 ShenandoahHeapRegion* r;
1023 while ((r =_cs->claim_next()) != NULL) {
1024 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
1025 worker_id,
1026 r->region_number());
1027
1028 assert(r->has_live(), "all-garbage regions are reclaimed early");
1029 _sh->marked_object_iterate(r, &cl);
1030
1031 if (_sh->check_cancelled_gc_and_yield()) {
1032 log_develop_trace(gc, region)("Cancelled GC while evacuating region " SIZE_FORMAT, r->region_number());
1033 break;
1034 }
1035
1036 if (ShenandoahPacing) {
1037 _sh->pacer()->report_evac(r->get_live_data_words());
1038 }
1039 }
1040 }
1041 };
1042
1043 void ShenandoahHeap::trash_cset_regions() {
1044 ShenandoahHeapLocker locker(lock());
1045
1046 ShenandoahCollectionSet* set = collection_set();
1047 ShenandoahHeapRegion* r;
1048 set->clear_current_index();
1049 while ((r = set->next()) != NULL) {
1050 r->make_trash();
1051 }
1052 collection_set()->clear();
1053 }
1054
1055 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1056 st->print_cr("Heap Regions:");
1057 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1058 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1059 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1060 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1061
1062 for (size_t i = 0; i < num_regions(); i++) {
1063 get_region(i)->print_on(st);
1064 }
1065 }
1066
1067 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1068 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1069
1070 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
1071 size_t size = humongous_obj->size() + BrooksPointer::word_size();
1072 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1073 size_t index = start->region_number() + required_regions - 1;
1074
1075 assert(!start->has_live(), "liveness must be zero");
1076 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
1077
1078 for(size_t i = 0; i < required_regions; i++) {
1079 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1080 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1081 ShenandoahHeapRegion* region = get_region(index --);
1082
1083 LogTarget(Trace, gc, humongous) lt;
1084 if (lt.is_enabled()) {
1085 ResourceMark rm;
1086 LogStream ls(lt);
1087 region->print_on(&ls);
1088 }
1089
1090 assert(region->is_humongous(), "expect correct humongous start or continuation");
1091 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1092
1093 region->make_trash();
1094 }
1095 }
1096
1097 #ifdef ASSERT
1098 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1099 bool heap_region_do(ShenandoahHeapRegion* r) {
1100 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1101 return false;
1102 }
1103 };
1104 #endif
1105
1106 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1107 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1108
1109 if (!cancelled_gc()) {
1110 // Allocations might have happened before we STWed here, record peak:
1111 heuristics()->record_peak_occupancy();
1112
1113 make_tlabs_parsable(true);
1114
1115 if (ShenandoahVerify) {
1116 verifier()->verify_after_concmark();
1117 }
1118
1119 trash_cset_regions();
1120
1121 // NOTE: This needs to be done during a stop the world pause, because
1122 // putting regions into the collection set concurrently with Java threads
1123 // will create a race. In particular, acmp could fail because when we
1124 // resolve the first operand, the containing region might not yet be in
1125 // the collection set, and thus return the original oop. When the 2nd
1126 // operand gets resolved, the region could be in the collection set
1127 // and the oop gets evacuated. If both operands have originally been
1128 // the same, we get false negatives.
1129
1130 {
1131 ShenandoahHeapLocker locker(lock());
1132 _collection_set->clear();
1133 _free_set->clear();
1134
1135 #ifdef ASSERT
1136 ShenandoahCheckCollectionSetClosure ccsc;
1137 heap_region_iterate(&ccsc);
1138 #endif
1139
1140 heuristics()->choose_collection_set(_collection_set);
1141
1142 _free_set->rebuild();
1143 }
1144
1145 Universe::update_heap_info_at_gc();
1146
1147 if (ShenandoahVerify) {
1148 verifier()->verify_before_evacuation();
1149 }
1150 }
1151 }
1152
1153
1154 class ShenandoahRetireTLABClosure : public ThreadClosure {
1155 private:
1156 bool _retire;
1157
1158 public:
1159 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1160
1161 void do_thread(Thread* thread) {
1162 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1163 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1164 gclab->retire();
1165 }
1166 };
1167
1168 void ShenandoahHeap::make_tlabs_parsable(bool retire_tlabs) {
1169 if (UseTLAB) {
1170 CollectedHeap::ensure_parsability(retire_tlabs);
1171 }
1172 ShenandoahRetireTLABClosure cl(retire_tlabs);
1173 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1174 cl.do_thread(t);
1175 }
1176 gc_threads_do(&cl);
1177 }
1178
1179
1180 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1181 ShenandoahRootEvacuator* _rp;
1182 public:
1183
1184 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1185 AbstractGangTask("Shenandoah evacuate and update roots"),
1186 _rp(rp)
1187 {
1188 // Nothing else to do.
1189 }
1190
1191 void work(uint worker_id) {
1192 ShenandoahEvacOOMScope oom_evac_scope;
1193 ShenandoahEvacuateUpdateRootsClosure cl;
1194
1195 if (ShenandoahConcurrentEvacCodeRoots) {
1196 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1197 } else {
1198 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1199 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1200 }
1201 }
1202 };
1203
1204 class ShenandoahFixRootsTask : public AbstractGangTask {
1205 ShenandoahRootEvacuator* _rp;
1206 public:
1207
1208 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1209 AbstractGangTask("Shenandoah update roots"),
1210 _rp(rp)
1211 {
1212 // Nothing else to do.
1213 }
1214
1215 void work(uint worker_id) {
1216 ShenandoahEvacOOMScope oom_evac_scope;
1217 ShenandoahUpdateRefsClosure cl;
1218 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1219
1220 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1221 }
1222 };
1223
1224 void ShenandoahHeap::evacuate_and_update_roots() {
1225
1226 #if defined(COMPILER2) || INCLUDE_JVMCI
1227 DerivedPointerTable::clear();
1228 #endif
1229 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1230
1231 {
1232 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1233 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1234 workers()->run_task(&roots_task);
1235 }
1236
1237 #if defined(COMPILER2) || INCLUDE_JVMCI
1238 DerivedPointerTable::update_pointers();
1239 #endif
1240 if (cancelled_gc()) {
1241 fixup_roots();
1242 }
1243 }
1244
1245 void ShenandoahHeap::fixup_roots() {
1246 assert(cancelled_gc(), "Only after concurrent cycle failed");
1247
1248 // If initial evacuation has been cancelled, we need to update all references
1249 // after all workers have finished. Otherwise we might run into the following problem:
1250 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1251 // GC thread 2 evacuates the same object X to to-space
1252 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1253 // clear() and update_pointers() must always be called in pairs,
1254 // cannot nest with above clear()/update_pointers().
1255 #if defined(COMPILER2) || INCLUDE_JVMCI
1256 DerivedPointerTable::clear();
1257 #endif
1258 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1259 ShenandoahFixRootsTask update_roots_task(&rp);
1260 workers()->run_task(&update_roots_task);
1261 #if defined(COMPILER2) || INCLUDE_JVMCI
1262 DerivedPointerTable::update_pointers();
1263 #endif
1264 }
1265
1266 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1267 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1268
1269 CodeBlobToOopClosure blobsCl(cl, false);
1270 CLDToOopClosure cldCl(cl);
1271
1272 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1273 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1274 }
1275
1276 bool ShenandoahHeap::supports_tlab_allocation() const {
1277 return true;
1278 }
1279
1280 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1281 return MIN2(_free_set->unsafe_peek_free(), max_tlab_size());
1282 }
1283
1284 size_t ShenandoahHeap::max_tlab_size() const {
1285 return ShenandoahHeapRegion::max_tlab_size_bytes();
1286 }
1287
1288 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1289 public:
1290 void do_thread(Thread* thread) {
1291 ShenandoahHeap* heap = ShenandoahHeap::heap();
1292 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1293 if (thread->is_Java_thread()) {
1294 gclab->flush_and_retire_stats(heap->mutator_gclab_stats());
1295 } else {
1296 gclab->flush_and_retire_stats(heap->collector_gclab_stats());
1297 }
1298 }
1299 };
1300
1301 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1302 ShenandoahAccumulateStatisticsGCLABClosure cl;
1303 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1304 cl.do_thread(t);
1305 }
1306 gc_threads_do(&cl);
1307 _mutator_gclab_stats->adjust_desired_plab_sz();
1308 _collector_gclab_stats->adjust_desired_plab_sz();
1309 }
1310
1311 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1312 return true;
1313 }
1314
1315 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1316 // Overridden to do nothing.
1317 return new_obj;
1318 }
1319
1320 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1321 return true;
1322 }
1323
1324 bool ShenandoahHeap::card_mark_must_follow_store() const {
1325 return false;
1326 }
1327
1328 void ShenandoahHeap::collect(GCCause::Cause cause) {
1329 control_thread()->handle_explicit_gc(cause);
1330 }
1331
1332 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1333 //assert(false, "Shouldn't need to do full collections");
1334 }
1335
1336 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1337 Unimplemented();
1338 return NULL;
1339
1340 }
1341
1342 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1343 return _shenandoah_policy;
1344 }
1345
1346
1347 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1348 Space* sp = heap_region_containing(addr);
1349 if (sp != NULL) {
1350 return sp->block_start(addr);
1351 }
1352 return NULL;
1353 }
1354
1355 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1356 Space* sp = heap_region_containing(addr);
1357 assert(sp != NULL, "block_size of address outside of heap");
1358 return sp->block_size(addr);
1359 }
1360
1361 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1362 Space* sp = heap_region_containing(addr);
1363 return sp->block_is_obj(addr);
1364 }
1365
1366 jlong ShenandoahHeap::millis_since_last_gc() {
1367 return 0;
1368 }
1369
1370 void ShenandoahHeap::prepare_for_verify() {
1371 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1372 make_tlabs_parsable(false);
1373 }
1374 }
1375
1376 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1377 workers()->print_worker_threads_on(st);
1378 if (ShenandoahStringDedup::is_enabled()) {
1379 ShenandoahStringDedup::print_worker_threads_on(st);
1380 }
1381 }
1382
1383 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1384 workers()->threads_do(tcl);
1385 if (ShenandoahStringDedup::is_enabled()) {
1386 ShenandoahStringDedup::threads_do(tcl);
1387 }
1388 }
1389
1390 void ShenandoahHeap::print_tracing_info() const {
1391 LogTarget(Info, gc, stats) lt;
1392 if (lt.is_enabled()) {
1393 ResourceMark rm;
1394 LogStream ls(lt);
1395
1396 phase_timings()->print_on(&ls);
1397
1398 ls.cr();
1399 ls.cr();
1400
1401 shenandoahPolicy()->print_gc_stats(&ls);
1402
1403 ls.cr();
1404 ls.cr();
1405
1406 if (ShenandoahPacing) {
1407 pacer()->print_on(&ls);
1408 }
1409
1410 ls.cr();
1411 ls.cr();
1412
1413 if (ShenandoahAllocationTrace) {
1414 assert(alloc_tracker() != NULL, "Must be");
1415 alloc_tracker()->print_on(&ls);
1416 } else {
1417 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1418 }
1419 }
1420 }
1421
1422 void ShenandoahHeap::verify(VerifyOption vo) {
1423 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1424 if (ShenandoahVerify) {
1425 verifier()->verify_generic(vo);
1426 } else {
1427 // TODO: Consider allocating verification bitmaps on demand,
1428 // and turn this on unconditionally.
1429 }
1430 }
1431 }
1432 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1433 return _free_set->capacity();
1434 }
1435
1436 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1437 private:
1438 MarkBitMap* _bitmap;
1439 Stack<oop,mtGC>* _oop_stack;
1440
1441 template <class T>
1442 void do_oop_work(T* p) {
1443 T o = RawAccess<>::oop_load(p);
1444 if (!CompressedOops::is_null(o)) {
1445 oop obj = CompressedOops::decode_not_null(o);
1446 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1447 assert(oopDesc::is_oop(obj), "must be a valid oop");
1448 if (!_bitmap->isMarked((HeapWord*) obj)) {
1449 _bitmap->mark((HeapWord*) obj);
1450 _oop_stack->push(obj);
1451 }
1452 }
1453 }
1454 public:
1455 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1456 _bitmap(bitmap), _oop_stack(oop_stack) {}
1457 void do_oop(oop* p) { do_oop_work(p); }
1458 void do_oop(narrowOop* p) { do_oop_work(p); }
1459 };
1460
1461 /*
1462 * This is public API, used in preparation of object_iterate().
1463 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1464 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1465 * control, we call SH::make_tlabs_parsable().
1466 */
1467 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1468 // No-op.
1469 }
1470
1471 /*
1472 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1473 *
1474 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1475 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1476 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1477 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1478 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1479 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1480 * wiped the bitmap in preparation for next marking).
1481 *
1482 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1483 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1484 * is allowed to report dead objects, but is not required to do so.
1485 */
1486 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1487 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1488 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1489 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1490 return;
1491 }
1492
1493 Stack<oop,mtGC> oop_stack;
1494
1495 // First, we process all GC roots. This populates the work stack with initial objects.
1496 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1497 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1498 CLDToOopClosure clds(&oops, false);
1499 CodeBlobToOopClosure blobs(&oops, false);
1500 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1501
1502 // Work through the oop stack to traverse heap.
1503 while (! oop_stack.is_empty()) {
1504 oop obj = oop_stack.pop();
1505 assert(oopDesc::is_oop(obj), "must be a valid oop");
1506 cl->do_object(obj);
1507 obj->oop_iterate(&oops);
1508 }
1509
1510 assert(oop_stack.is_empty(), "should be empty");
1511
1512 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1513 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1514 }
1515 }
1516
1517 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1518 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1519 object_iterate(cl);
1520 }
1521
1522 // Apply blk->heap_region_do() on all committed regions in address order,
1523 // terminating the iteration early if heap_region_do() returns true.
1524 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1525 for (size_t i = 0; i < num_regions(); i++) {
1526 ShenandoahHeapRegion* current = get_region(i);
1527 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1528 continue;
1529 }
1530 if (skip_cset_regions && in_collection_set(current)) {
1531 continue;
1532 }
1533 if (blk->heap_region_do(current)) {
1534 return;
1535 }
1536 }
1537 }
1538
1539 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1540 private:
1541 ShenandoahHeap* sh;
1542 public:
1543 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1544
1545 bool heap_region_do(ShenandoahHeapRegion* r) {
1546 r->clear_live_data();
1547 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1548 return false;
1549 }
1550 };
1551
1552 void ShenandoahHeap::op_init_mark() {
1553 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1554
1555 assert(is_next_bitmap_clear(), "need clear marking bitmap");
1556
1557 if (ShenandoahVerify) {
1558 verifier()->verify_before_concmark();
1559 }
1560
1561 {
1562 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1563 accumulate_statistics_all_tlabs();
1564 }
1565
1566 set_concurrent_mark_in_progress(true);
1567 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1568 {
1569 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1570 make_tlabs_parsable(true);
1571 }
1572
1573 {
1574 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1575 ShenandoahClearLivenessClosure clc(this);
1576 heap_region_iterate(&clc);
1577 }
1578
1579 // Make above changes visible to worker threads
1580 OrderAccess::fence();
1581
1582 concurrentMark()->init_mark_roots();
1583
1584 if (UseTLAB) {
1585 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1586 resize_all_tlabs();
1587 }
1588
1589 if (ShenandoahPacing) {
1590 pacer()->setup_for_mark();
1591 }
1592 }
1593
1594 void ShenandoahHeap::op_mark() {
1595 concurrentMark()->mark_from_roots();
1596
1597 // Allocations happen during concurrent mark, record peak after the phase:
1598 heuristics()->record_peak_occupancy();
1599 }
1600
1601 void ShenandoahHeap::op_final_mark() {
1602 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1603
1604 // It is critical that we
1605 // evacuate roots right after finishing marking, so that we don't
1606 // get unmarked objects in the roots.
1607
1608 if (!cancelled_gc()) {
1609 concurrentMark()->finish_mark_from_roots();
1610 stop_concurrent_marking();
1611
1612 {
1613 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1614 prepare_for_concurrent_evacuation();
1615 }
1616
1617 // If collection set has candidates, start evacuation.
1618 // Otherwise, bypass the rest of the cycle.
1619 if (!collection_set()->is_empty()) {
1620 set_evacuation_in_progress(true);
1621 // From here on, we need to update references.
1622 set_has_forwarded_objects(true);
1623
1624 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1625 evacuate_and_update_roots();
1626 }
1627
1628 if (ShenandoahPacing) {
1629 pacer()->setup_for_evac();
1630 }
1631 } else {
1632 concurrentMark()->cancel();
1633 stop_concurrent_marking();
1634
1635 if (process_references()) {
1636 // Abandon reference processing right away: pre-cleaning must have failed.
1637 ReferenceProcessor *rp = ref_processor();
1638 rp->disable_discovery();
1639 rp->abandon_partial_discovery();
1640 rp->verify_no_references_recorded();
1641 }
1642 }
1643 }
1644
1645 void ShenandoahHeap::op_final_evac() {
1646 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1647
1648 accumulate_statistics_all_gclabs();
1649 set_evacuation_in_progress(false);
1650 if (ShenandoahVerify) {
1651 verifier()->verify_after_evacuation();
1652 }
1653 }
1654
1655 void ShenandoahHeap::op_evac() {
1656
1657 LogTarget(Trace, gc, region) lt_region;
1658 LogTarget(Trace, gc, cset) lt_cset;
1659
1660 if (lt_region.is_enabled()) {
1661 ResourceMark rm;
1662 LogStream ls(lt_region);
1663 ls.print_cr("All available regions:");
1664 print_heap_regions_on(&ls);
1665 }
1666
1667 if (lt_cset.is_enabled()) {
1668 ResourceMark rm;
1669 LogStream ls(lt_cset);
1670 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1671 _collection_set->print_on(&ls);
1672
1673 ls.print_cr("Free set:");
1674 _free_set->print_on(&ls);
1675 }
1676
1677 ShenandoahParallelEvacuationTask task(this, _collection_set);
1678 workers()->run_task(&task);
1679
1680 if (lt_cset.is_enabled()) {
1681 ResourceMark rm;
1682 LogStream ls(lt_cset);
1683 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1684 _collection_set->count());
1685 _collection_set->print_on(&ls);
1686
1687 ls.print_cr("After evacuation free set:");
1688 _free_set->print_on(&ls);
1689 }
1690
1691 if (lt_region.is_enabled()) {
1692 ResourceMark rm;
1693 LogStream ls(lt_region);
1694 ls.print_cr("All regions after evacuation:");
1695 print_heap_regions_on(&ls);
1696 }
1697
1698 // Allocations happen during evacuation, record peak after the phase:
1699 heuristics()->record_peak_occupancy();
1700 }
1701
1702 void ShenandoahHeap::op_updaterefs() {
1703 update_heap_references(true);
1704
1705 // Allocations happen during update-refs, record peak after the phase:
1706 heuristics()->record_peak_occupancy();
1707 }
1708
1709 void ShenandoahHeap::op_cleanup() {
1710 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1711 free_set()->recycle_trash();
1712
1713 // Allocations happen during cleanup, record peak after the phase:
1714 heuristics()->record_peak_occupancy();
1715 }
1716
1717 void ShenandoahHeap::op_cleanup_bitmaps() {
1718 op_cleanup();
1719
1720 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1721 reset_next_mark_bitmap();
1722
1723 // Allocations happen during bitmap cleanup, record peak after the phase:
1724 heuristics()->record_peak_occupancy();
1725 }
1726
1727 void ShenandoahHeap::op_cleanup_traversal() {
1728
1729 {
1730 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1731 reset_next_mark_bitmap_traversal();
1732 }
1733
1734 op_cleanup();
1735
1736 // Allocations happen during bitmap cleanup, record peak after the phase:
1737 heuristics()->record_peak_occupancy();
1738 }
1739
1740 void ShenandoahHeap::op_preclean() {
1741 concurrentMark()->preclean_weak_refs();
1742
1743 // Allocations happen during concurrent preclean, record peak after the phase:
1744 heuristics()->record_peak_occupancy();
1745 }
1746
1747 void ShenandoahHeap::op_init_traversal() {
1748 traversal_gc()->init_traversal_collection();
1749 }
1750
1751 void ShenandoahHeap::op_traversal() {
1752 traversal_gc()->concurrent_traversal_collection();
1753 }
1754
1755 void ShenandoahHeap::op_final_traversal() {
1756 traversal_gc()->final_traversal_collection();
1757 }
1758
1759 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1760 ShenandoahMetricsSnapshot metrics;
1761 metrics.snap_before();
1762
1763 full_gc()->do_it(cause);
1764 if (UseTLAB) {
1765 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1766 resize_all_tlabs();
1767 }
1768
1769 metrics.snap_after();
1770 metrics.print();
1771
1772 if (metrics.is_good_progress("Full GC")) {
1773 _progress_last_gc.set();
1774 } else {
1775 // Nothing to do. Tell the allocation path that we have failed to make
1776 // progress, and it can finally fail.
1777 _progress_last_gc.unset();
1778 }
1779 }
1780
1781 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1782 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1783 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1784 // some phase, we have to upgrade the Degenerate GC to Full GC.
1785
1786 clear_cancelled_gc();
1787
1788 ShenandoahMetricsSnapshot metrics;
1789 metrics.snap_before();
1790
1791 switch (point) {
1792 case _degenerated_evac:
1793 // Not possible to degenerate from here, upgrade to Full GC right away.
1794 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1795 op_degenerated_fail();
1796 return;
1797
1798 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1799 // but enters it at different points, depending on which concurrent phase had
1800 // degenerated.
1801
1802 case _degenerated_traversal:
1803 {
1804 ShenandoahHeapLocker locker(lock());
1805 collection_set()->clear_current_index();
1806 for (size_t i = 0; i < collection_set()->count(); i++) {
1807 ShenandoahHeapRegion* r = collection_set()->next();
1808 r->make_regular_bypass();
1809 }
1810 collection_set()->clear();
1811 }
1812 op_final_traversal();
1813 op_cleanup_traversal();
1814 return;
1815
1816 case _degenerated_outside_cycle:
1817 if (heuristics()->can_do_traversal_gc()) {
1818 // Not possible to degenerate from here, upgrade to Full GC right away.
1819 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1820 op_degenerated_fail();
1821 return;
1822 }
1823 op_init_mark();
1824 if (cancelled_gc()) {
1825 op_degenerated_fail();
1826 return;
1827 }
1828
1829 case _degenerated_mark:
1830 op_final_mark();
1831 if (cancelled_gc()) {
1832 op_degenerated_fail();
1833 return;
1834 }
1835
1836 op_cleanup();
1837
1838 // If heuristics thinks we should do the cycle, this flag would be set,
1839 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1840 if (is_evacuation_in_progress()) {
1841 op_evac();
1842 if (cancelled_gc()) {
1843 op_degenerated_fail();
1844 return;
1845 }
1846 }
1847
1848 // If heuristics thinks we should do the cycle, this flag would be set,
1849 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1850 if (has_forwarded_objects()) {
1851 op_init_updaterefs();
1852 if (cancelled_gc()) {
1853 op_degenerated_fail();
1854 return;
1855 }
1856 }
1857
1858 case _degenerated_updaterefs:
1859 if (has_forwarded_objects()) {
1860 op_final_updaterefs();
1861 if (cancelled_gc()) {
1862 op_degenerated_fail();
1863 return;
1864 }
1865 }
1866
1867 op_cleanup_bitmaps();
1868 break;
1869
1870 default:
1871 ShouldNotReachHere();
1872 }
1873
1874 if (ShenandoahVerify) {
1875 verifier()->verify_after_degenerated();
1876 }
1877
1878 metrics.snap_after();
1879 metrics.print();
1880
1881 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1882 // because that probably means the heap is overloaded and/or fragmented.
1883 if (!metrics.is_good_progress("Degenerated GC")) {
1884 _progress_last_gc.unset();
1885 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1886 op_degenerated_futile();
1887 } else {
1888 _progress_last_gc.set();
1889 }
1890 }
1891
1892 void ShenandoahHeap::op_degenerated_fail() {
1893 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1894 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1895 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1896 }
1897
1898 void ShenandoahHeap::op_degenerated_futile() {
1899 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1900 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1901 }
1902
1903 void ShenandoahHeap::swap_mark_bitmaps() {
1904 // Swap bitmaps.
1905 MarkBitMap* tmp1 = _complete_mark_bit_map;
1906 _complete_mark_bit_map = _next_mark_bit_map;
1907 _next_mark_bit_map = tmp1;
1908
1909 // Swap top-at-mark-start pointers
1910 HeapWord** tmp2 = _complete_top_at_mark_starts;
1911 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1912 _next_top_at_mark_starts = tmp2;
1913
1914 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1915 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1916 _next_top_at_mark_starts_base = tmp3;
1917 }
1918
1919
1920 void ShenandoahHeap::stop_concurrent_marking() {
1921 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1922 if (!cancelled_gc()) {
1923 // If we needed to update refs, and concurrent marking has been cancelled,
1924 // we need to finish updating references.
1925 set_has_forwarded_objects(false);
1926 swap_mark_bitmaps();
1927 }
1928 set_concurrent_mark_in_progress(false);
1929
1930 LogTarget(Trace, gc, region) lt;
1931 if (lt.is_enabled()) {
1932 ResourceMark rm;
1933 LogStream ls(lt);
1934 ls.print_cr("Regions at stopping the concurrent mark:");
1935 print_heap_regions_on(&ls);
1936 }
1937 }
1938
1939 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1940 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1941 ShenandoahThreadLocalData::set_gc_state(t, state);
1942 }
1943 }
1944
1945 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1946 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1947 _gc_state.set_cond(mask, value);
1948 set_gc_state_all_threads(_gc_state.raw_value());
1949 }
1950
1951 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1952 set_gc_state_mask(MARKING, in_progress);
1953 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1954 }
1955
1956 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1957 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1958 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1959 }
1960
1961 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1962 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1963 set_gc_state_mask(EVACUATION, in_progress);
1964 }
1965
1966 uint ShenandoahHeap::oop_extra_words() {
1967 return BrooksPointer::word_size();
1968 }
1969
1970 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1971 _heap(ShenandoahHeap::heap_no_check()) {
1972 }
1973
1974 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1975 _heap(ShenandoahHeap::heap_no_check()) {
1976 }
1977
1978 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1979 if (CompressedOops::is_null(obj)) {
1980 return false;
1981 }
1982 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1983 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_mark_in_progress() || _heap->is_concurrent_traversal_in_progress())
1984 return _heap->is_marked_next(obj);
1985 }
1986
1987 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1988 if (CompressedOops::is_null(obj)) {
1989 return false;
1990 }
1991 shenandoah_assert_not_forwarded(NULL, obj);
1992 return _heap->is_marked_next(obj);
1993 }
1994
1995 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1996 return has_forwarded_objects() ?
1997 (BoolObjectClosure*) &_forwarded_is_alive :
1998 (BoolObjectClosure*) &_is_alive;
1999 }
2000
2001 void ShenandoahHeap::ref_processing_init() {
2002 MemRegion mr = reserved_region();
2003
2004 _forwarded_is_alive.init(this);
2005 _is_alive.init(this);
2006 assert(_max_workers > 0, "Sanity");
2007
2008 _ref_processor =
2009 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2010 ParallelRefProcEnabled, // MT processing
2011 _max_workers, // Degree of MT processing
2012 true, // MT discovery
2013 _max_workers, // Degree of MT discovery
2014 false, // Reference discovery is not atomic
2015 NULL); // No closure, should be installed before use
2016
2017 shenandoah_assert_rp_isalive_not_installed();
2018 }
2019
2020
2021 GCTracer* ShenandoahHeap::tracer() {
2022 return shenandoahPolicy()->tracer();
2023 }
2024
2025 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2026 return _free_set->used();
2027 }
2028
2029 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2030 if (try_cancel_gc()) {
2031 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2032 log_info(gc)("%s", msg.buffer());
2033 Events::log(Thread::current(), "%s", msg.buffer());
2034 }
2035 }
2036
2037 uint ShenandoahHeap::max_workers() {
2038 return _max_workers;
2039 }
2040
2041 void ShenandoahHeap::stop() {
2042 // The shutdown sequence should be able to terminate when GC is running.
2043
2044 // Step 0. Notify policy to disable event recording.
2045 _shenandoah_policy->record_shutdown();
2046
2047 // Step 1. Notify control thread that we are in shutdown.
2048 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2049 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2050 control_thread()->prepare_for_graceful_shutdown();
2051
2052 // Step 2. Notify GC workers that we are cancelling GC.
2053 cancel_gc(GCCause::_shenandoah_stop_vm);
2054
2055 // Step 3. Wait until GC worker exits normally.
2056 control_thread()->stop();
2057
2058 // Step 4. Stop String Dedup thread if it is active
2059 if (ShenandoahStringDedup::is_enabled()) {
2060 ShenandoahStringDedup::stop();
2061 }
2062 }
2063
2064 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
2065 assert(ClassUnloading || full_gc, "Class unloading should be enabled");
2066
2067 ShenandoahPhaseTimings::Phase phase_root =
2068 full_gc ?
2069 ShenandoahPhaseTimings::full_gc_purge :
2070 ShenandoahPhaseTimings::purge;
2071
2072 ShenandoahPhaseTimings::Phase phase_unload =
2073 full_gc ?
2074 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2075 ShenandoahPhaseTimings::purge_class_unload;
2076
2077 ShenandoahPhaseTimings::Phase phase_cldg =
2078 full_gc ?
2079 ShenandoahPhaseTimings::full_gc_purge_cldg :
2080 ShenandoahPhaseTimings::purge_cldg;
2081
2082 ShenandoahPhaseTimings::Phase phase_par =
2083 full_gc ?
2084 ShenandoahPhaseTimings::full_gc_purge_par :
2085 ShenandoahPhaseTimings::purge_par;
2086
2087 ShenandoahPhaseTimings::Phase phase_par_classes =
2088 full_gc ?
2089 ShenandoahPhaseTimings::full_gc_purge_par_classes :
2090 ShenandoahPhaseTimings::purge_par_classes;
2091
2092 ShenandoahPhaseTimings::Phase phase_par_codecache =
2093 full_gc ?
2094 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
2095 ShenandoahPhaseTimings::purge_par_codecache;
2096
2097 ShenandoahPhaseTimings::Phase phase_par_rmt =
2098 full_gc ?
2099 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
2100 ShenandoahPhaseTimings::purge_par_rmt;
2101
2102 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2103 full_gc ?
2104 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2105 ShenandoahPhaseTimings::purge_par_symbstring;
2106
2107 ShenandoahPhaseTimings::Phase phase_par_sync =
2108 full_gc ?
2109 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2110 ShenandoahPhaseTimings::purge_par_sync;
2111
2112 ShenandoahGCPhase root_phase(phase_root);
2113
2114 BoolObjectClosure* is_alive = is_alive_closure();
2115
2116 bool purged_class;
2117
2118 // Unload classes and purge SystemDictionary.
2119 {
2120 ShenandoahGCPhase phase(phase_unload);
2121 purged_class = SystemDictionary::do_unloading(gc_timer(),
2122 full_gc /* do_cleaning*/ );
2123 }
2124
2125 {
2126 ShenandoahGCPhase phase(phase_par);
2127 uint active = _workers->active_workers();
2128 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
2129 _workers->run_task(&unlink_task);
2130
2131 ShenandoahPhaseTimings* p = phase_timings();
2132 ParallelCleaningTimes times = unlink_task.times();
2133
2134 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2135 // by active workers to get average time per worker, that would add up to wall time.
2136 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2137 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2138 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
2139 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2140 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2141 }
2142
2143 if (ShenandoahStringDedup::is_enabled()) {
2144 ShenandoahPhaseTimings::Phase phase_par_string_dedup =
2145 full_gc ?
2146 ShenandoahPhaseTimings::full_gc_purge_par_string_dedup :
2147 ShenandoahPhaseTimings::purge_par_string_dedup;
2148 ShenandoahGCPhase phase(phase_par_string_dedup);
2149 ShenandoahStringDedup::parallel_cleanup();
2150 }
2151
2152
2153 {
2154 ShenandoahGCPhase phase(phase_cldg);
2155 ClassLoaderDataGraph::purge();
2156 }
2157 }
2158
2159 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2160 set_gc_state_mask(HAS_FORWARDED, cond);
2161 }
2162
2163 bool ShenandoahHeap::last_gc_made_progress() const {
2164 return _progress_last_gc.is_set();
2165 }
2166
2167 void ShenandoahHeap::set_process_references(bool pr) {
2168 _process_references.set_cond(pr);
2169 }
2170
2171 void ShenandoahHeap::set_unload_classes(bool uc) {
2172 _unload_classes.set_cond(uc);
2173 }
2174
2175 bool ShenandoahHeap::process_references() const {
2176 return _process_references.is_set();
2177 }
2178
2179 bool ShenandoahHeap::unload_classes() const {
2180 return _unload_classes.is_set();
2181 }
2182
2183 //fixme this should be in heapregionset
2184 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2185 size_t region_idx = r->region_number() + 1;
2186 ShenandoahHeapRegion* next = get_region(region_idx);
2187 guarantee(next->region_number() == region_idx, "region number must match");
2188 while (next->is_humongous()) {
2189 region_idx = next->region_number() + 1;
2190 next = get_region(region_idx);
2191 guarantee(next->region_number() == region_idx, "region number must match");
2192 }
2193 return next;
2194 }
2195
2196 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2197 return _monitoring_support;
2198 }
2199
2200 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
2201 return _complete_mark_bit_map;
2202 }
2203
2204 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
2205 return _next_mark_bit_map;
2206 }
2207
2208 address ShenandoahHeap::in_cset_fast_test_addr() {
2209 ShenandoahHeap* heap = ShenandoahHeap::heap();
2210 assert(heap->collection_set() != NULL, "Sanity");
2211 return (address) heap->collection_set()->biased_map_address();
2212 }
2213
2214 address ShenandoahHeap::cancelled_gc_addr() {
2215 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2216 }
2217
2218 address ShenandoahHeap::gc_state_addr() {
2219 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2220 }
2221
2222 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2223 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2224 }
2225
2226 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2227 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2228 }
2229
2230 ShenandoahPacer* ShenandoahHeap::pacer() const {
2231 assert (_pacer != NULL, "sanity");
2232 return _pacer;
2233 }
2234
2235 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2236 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2237 _next_top_at_mark_starts[index] = addr;
2238 }
2239
2240 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2241 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2242 return _next_top_at_mark_starts[index];
2243 }
2244
2245 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2246 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2247 _complete_top_at_mark_starts[index] = addr;
2248 }
2249
2250 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2251 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2252 return _complete_top_at_mark_starts[index];
2253 }
2254
2255 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2256 _degenerated_gc_in_progress.set_cond(in_progress);
2257 }
2258
2259 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2260 _full_gc_in_progress.set_cond(in_progress);
2261 }
2262
2263 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2264 assert (is_full_gc_in_progress(), "should be");
2265 _full_gc_move_in_progress.set_cond(in_progress);
2266 }
2267
2268 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2269 set_gc_state_mask(UPDATEREFS, in_progress);
2270 }
2271
2272 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2273 ShenandoahCodeRoots::add_nmethod(nm);
2274 }
2275
2276 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2277 ShenandoahCodeRoots::remove_nmethod(nm);
2278 }
2279
2280 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2281 o = ShenandoahBarrierSet::barrier_set()->write_barrier(o);
2282 ShenandoahHeapLocker locker(lock());
2283 heap_region_containing(o)->make_pinned();
2284 return o;
2285 }
2286
2287 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2288 o = ShenandoahBarrierSet::barrier_set()->read_barrier(o);
2289 ShenandoahHeapLocker locker(lock());
2290 heap_region_containing(o)->make_unpinned();
2291 }
2292
2293 GCTimer* ShenandoahHeap::gc_timer() const {
2294 return _gc_timer;
2295 }
2296
2297 #ifdef ASSERT
2298 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2299 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2300
2301 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2302 if (UseDynamicNumberOfGCThreads ||
2303 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2304 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2305 } else {
2306 // Use ParallelGCThreads inside safepoints
2307 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2308 }
2309 } else {
2310 if (UseDynamicNumberOfGCThreads ||
2311 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2312 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2313 } else {
2314 // Use ConcGCThreads outside safepoints
2315 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2316 }
2317 }
2318 }
2319 #endif
2320
2321 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
2322 return _connection_matrix;
2323 }
2324
2325 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2326 return _traversal_gc;
2327 }
2328
2329 ShenandoahVerifier* ShenandoahHeap::verifier() {
2330 guarantee(ShenandoahVerify, "Should be enabled");
2331 assert (_verifier != NULL, "sanity");
2332 return _verifier;
2333 }
2334
2335 template<class T>
2336 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2337 private:
2338 T cl;
2339 ShenandoahHeap* _heap;
2340 ShenandoahRegionIterator* _regions;
2341 bool _concurrent;
2342 public:
2343 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2344 AbstractGangTask("Concurrent Update References Task"),
2345 cl(T()),
2346 _heap(ShenandoahHeap::heap()),
2347 _regions(regions),
2348 _concurrent(concurrent) {
2349 }
2350
2351 void work(uint worker_id) {
2352 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2353 ShenandoahHeapRegion* r = _regions->next();
2354 while (r != NULL) {
2355 if (_heap->in_collection_set(r)) {
2356 HeapWord* bottom = r->bottom();
2357 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2358 if (top > bottom) {
2359 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2360 }
2361 } else {
2362 if (r->is_active()) {
2363 _heap->marked_object_oop_safe_iterate(r, &cl);
2364 if (ShenandoahPacing) {
2365 _heap->pacer()->report_updaterefs(r->get_live_data_words());
2366 }
2367 }
2368 }
2369 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2370 return;
2371 }
2372 r = _regions->next();
2373 }
2374 }
2375 };
2376
2377 void ShenandoahHeap::update_heap_references(bool concurrent) {
2378 if (UseShenandoahMatrix) {
2379 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(&_update_refs_iterator, concurrent);
2380 workers()->run_task(&task);
2381 } else {
2382 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2383 workers()->run_task(&task);
2384 }
2385 }
2386
2387 void ShenandoahHeap::op_init_updaterefs() {
2388 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2389
2390 if (ShenandoahVerify) {
2391 verifier()->verify_before_updaterefs();
2392 }
2393
2394 accumulate_statistics_all_gclabs();
2395 set_evacuation_in_progress(false);
2396 set_update_refs_in_progress(true);
2397 make_tlabs_parsable(true);
2398 if (UseShenandoahMatrix) {
2399 connection_matrix()->clear_all();
2400 }
2401 for (uint i = 0; i < num_regions(); i++) {
2402 ShenandoahHeapRegion* r = get_region(i);
2403 r->set_concurrent_iteration_safe_limit(r->top());
2404 }
2405
2406 // Reset iterator.
2407 _update_refs_iterator.reset();
2408
2409 if (ShenandoahPacing) {
2410 pacer()->setup_for_updaterefs();
2411 }
2412 }
2413
2414 void ShenandoahHeap::op_final_updaterefs() {
2415 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2416
2417 // Check if there is left-over work, and finish it
2418 if (_update_refs_iterator.has_next()) {
2419 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2420
2421 // Finish updating references where we left off.
2422 clear_cancelled_gc();
2423 update_heap_references(false);
2424 }
2425
2426 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2427 // everything. On degenerated paths, cancelled gc would not be set anyway.
2428 if (cancelled_gc()) {
2429 clear_cancelled_gc();
2430 }
2431 assert(!cancelled_gc(), "Should have been done right before");
2432
2433 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2434
2435 // Allocations might have happened before we STWed here, record peak:
2436 heuristics()->record_peak_occupancy();
2437
2438 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2439
2440 trash_cset_regions();
2441 set_has_forwarded_objects(false);
2442
2443 if (ShenandoahVerify) {
2444 verifier()->verify_after_updaterefs();
2445 }
2446
2447 {
2448 ShenandoahHeapLocker locker(lock());
2449 _free_set->rebuild();
2450 }
2451
2452 set_update_refs_in_progress(false);
2453 }
2454
2455 void ShenandoahHeap::set_alloc_seq_gc_start() {
2456 // Take next number, the start seq number is inclusive
2457 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2458 }
2459
2460 void ShenandoahHeap::set_alloc_seq_gc_end() {
2461 // Take current number, the end seq number is also inclusive
2462 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2463 }
2464
2465
2466 #ifdef ASSERT
2467 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2468 _lock.assert_owned_by_current_thread();
2469 }
2470
2471 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2472 _lock.assert_not_owned_by_current_thread();
2473 }
2474
2475 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2476 _lock.assert_owned_by_current_thread_or_safepoint();
2477 }
2478 #endif
2479
2480 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2481 print_on(st);
2482 print_heap_regions_on(st);
2483 }
2484
2485 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2486 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2487
2488 size_t regions_from = _bitmap_regions_per_slice * slice;
2489 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2490 for (size_t g = regions_from; g < regions_to; g++) {
2491 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2492 if (skip_self && g == r->region_number()) continue;
2493 if (get_region(g)->is_committed()) {
2494 return true;
2495 }
2496 }
2497 return false;
2498 }
2499
2500 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2501 assert_heaplock_owned_by_current_thread();
2502
2503 if (is_bitmap_slice_committed(r, true)) {
2504 // Some other region from the group is already committed, meaning the bitmap
2505 // slice is already committed, we exit right away.
2506 return true;
2507 }
2508
2509 // Commit the bitmap slice:
2510 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2511 size_t off = _bitmap_bytes_per_slice * slice;
2512 size_t len = _bitmap_bytes_per_slice;
2513 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2514 return false;
2515 }
2516 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2517 return false;
2518 }
2519 return true;
2520 }
2521
2522 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2523 assert_heaplock_owned_by_current_thread();
2524
2525 if (is_bitmap_slice_committed(r, true)) {
2526 // Some other region from the group is still committed, meaning the bitmap
2527 // slice is should stay committed, exit right away.
2528 return true;
2529 }
2530
2531 // Uncommit the bitmap slice:
2532 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2533 size_t off = _bitmap_bytes_per_slice * slice;
2534 size_t len = _bitmap_bytes_per_slice;
2535 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2536 return false;
2537 }
2538 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2539 return false;
2540 }
2541 return true;
2542 }
2543
2544 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2545 assert_heaplock_owned_by_current_thread();
2546 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2547
2548 if (is_bitmap_slice_committed(r, true)) {
2549 // Some other region from the group is still committed, meaning the bitmap
2550 // slice is should stay committed, exit right away.
2551 return true;
2552 }
2553
2554 // Idle the bitmap slice:
2555 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2556 size_t off = _bitmap_bytes_per_slice * slice;
2557 size_t len = _bitmap_bytes_per_slice;
2558 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2559 return false;
2560 }
2561 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2562 return false;
2563 }
2564 return true;
2565 }
2566
2567 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2568 assert_heaplock_owned_by_current_thread();
2569 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2570 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2571 size_t off = _bitmap_bytes_per_slice * slice;
2572 size_t len = _bitmap_bytes_per_slice;
2573 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2574 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2575 }
2576
2577 void ShenandoahHeap::safepoint_synchronize_begin() {
2578 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2579 SuspendibleThreadSet::synchronize();
2580 }
2581 }
2582
2583 void ShenandoahHeap::safepoint_synchronize_end() {
2584 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2585 SuspendibleThreadSet::desynchronize();
2586 }
2587 }
2588
2589 void ShenandoahHeap::vmop_entry_init_mark() {
2590 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2591 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2592 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2593
2594 try_inject_alloc_failure();
2595 VM_ShenandoahInitMark op;
2596 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2597 }
2598
2599 void ShenandoahHeap::vmop_entry_final_mark() {
2600 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2601 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2602 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2603
2604 try_inject_alloc_failure();
2605 VM_ShenandoahFinalMarkStartEvac op;
2606 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2607 }
2608
2609 void ShenandoahHeap::vmop_entry_final_evac() {
2610 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2611 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2612 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2613
2614 VM_ShenandoahFinalEvac op;
2615 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2616 }
2617
2618 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2619 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2620 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2621 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2622
2623 try_inject_alloc_failure();
2624 VM_ShenandoahInitUpdateRefs op;
2625 VMThread::execute(&op);
2626 }
2627
2628 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2629 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2630 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2631 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2632
2633 try_inject_alloc_failure();
2634 VM_ShenandoahFinalUpdateRefs op;
2635 VMThread::execute(&op);
2636 }
2637
2638 void ShenandoahHeap::vmop_entry_init_traversal() {
2639 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2640 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2641 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2642
2643 try_inject_alloc_failure();
2644 VM_ShenandoahInitTraversalGC op;
2645 VMThread::execute(&op);
2646 }
2647
2648 void ShenandoahHeap::vmop_entry_final_traversal() {
2649 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2650 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2651 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2652
2653 try_inject_alloc_failure();
2654 VM_ShenandoahFinalTraversalGC op;
2655 VMThread::execute(&op);
2656 }
2657
2658 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2659 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2660 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2661 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2662
2663 try_inject_alloc_failure();
2664 VM_ShenandoahFullGC op(cause);
2665 VMThread::execute(&op);
2666 }
2667
2668 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2669 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2670 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2671 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2672
2673 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2674 VMThread::execute(°enerated_gc);
2675 }
2676
2677 void ShenandoahHeap::entry_init_mark() {
2678 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2679 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2680
2681 FormatBuffer<> msg("Pause Init Mark%s%s%s",
2682 has_forwarded_objects() ? " (update refs)" : "",
2683 process_references() ? " (process refs)" : "",
2684 unload_classes() ? " (unload classes)" : "");
2685 GCTraceTime(Info, gc) time(msg, gc_timer());
2686 EventMark em("%s", msg.buffer());
2687
2688 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_init_marking());
2689
2690 op_init_mark();
2691 }
2692
2693 void ShenandoahHeap::entry_final_mark() {
2694 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2695 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2696
2697 FormatBuffer<> msg("Pause Final Mark%s%s%s",
2698 has_forwarded_objects() ? " (update refs)" : "",
2699 process_references() ? " (process refs)" : "",
2700 unload_classes() ? " (unload classes)" : "");
2701 GCTraceTime(Info, gc) time(msg, gc_timer());
2702 EventMark em("%s", msg.buffer());
2703
2704 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_marking());
2705
2706 op_final_mark();
2707 }
2708
2709 void ShenandoahHeap::entry_final_evac() {
2710 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2711 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2712
2713 FormatBuffer<> msg("Pause Final Evac");
2714 GCTraceTime(Info, gc) time(msg, gc_timer());
2715 EventMark em("%s", msg.buffer());
2716
2717 op_final_evac();
2718 }
2719
2720 void ShenandoahHeap::entry_init_updaterefs() {
2721 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2722 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2723
2724 static const char* msg = "Pause Init Update Refs";
2725 GCTraceTime(Info, gc) time(msg, gc_timer());
2726 EventMark em("%s", msg);
2727
2728 // No workers used in this phase, no setup required
2729
2730 op_init_updaterefs();
2731 }
2732
2733 void ShenandoahHeap::entry_final_updaterefs() {
2734 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2735 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2736
2737 static const char* msg = "Pause Final Update Refs";
2738 GCTraceTime(Info, gc) time(msg, gc_timer());
2739 EventMark em("%s", msg);
2740
2741 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_update_ref());
2742
2743 op_final_updaterefs();
2744 }
2745
2746 void ShenandoahHeap::entry_init_traversal() {
2747 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2748 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2749
2750 static const char* msg = "Pause Init Traversal";
2751 GCTraceTime(Info, gc) time(msg, gc_timer());
2752 EventMark em("%s", msg);
2753
2754 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2755
2756 op_init_traversal();
2757 }
2758
2759 void ShenandoahHeap::entry_final_traversal() {
2760 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2761 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2762
2763 static const char* msg = "Pause Final Traversal";
2764 GCTraceTime(Info, gc) time(msg, gc_timer());
2765 EventMark em("%s", msg);
2766
2767 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2768
2769 op_final_traversal();
2770 }
2771
2772 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2773 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2774 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2775
2776 static const char* msg = "Pause Full";
2777 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2778 EventMark em("%s", msg);
2779
2780 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_fullgc());
2781
2782 op_full(cause);
2783 }
2784
2785 void ShenandoahHeap::entry_degenerated(int point) {
2786 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2787 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2788
2789 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2790 FormatBuffer<> msg("Pause Degenerated GC (%s)", degen_point_to_string(dpoint));
2791 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2792 EventMark em("%s", msg.buffer());
2793
2794 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated());
2795
2796 set_degenerated_gc_in_progress(true);
2797 op_degenerated(dpoint);
2798 set_degenerated_gc_in_progress(false);
2799 }
2800
2801 void ShenandoahHeap::entry_mark() {
2802 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2803
2804 FormatBuffer<> msg("Concurrent marking%s%s%s",
2805 has_forwarded_objects() ? " (update refs)" : "",
2806 process_references() ? " (process refs)" : "",
2807 unload_classes() ? " (unload classes)" : "");
2808 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2809 EventMark em("%s", msg.buffer());
2810
2811 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_marking());
2812
2813 try_inject_alloc_failure();
2814 op_mark();
2815 }
2816
2817 void ShenandoahHeap::entry_evac() {
2818 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2819 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2820
2821 static const char* msg = "Concurrent evacuation";
2822 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2823 EventMark em("%s", msg);
2824
2825 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_evac());
2826
2827 try_inject_alloc_failure();
2828 op_evac();
2829 }
2830
2831 void ShenandoahHeap::entry_updaterefs() {
2832 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2833
2834 static const char* msg = "Concurrent update references";
2835 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2836 EventMark em("%s", msg);
2837
2838 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref());
2839
2840 try_inject_alloc_failure();
2841 op_updaterefs();
2842 }
2843 void ShenandoahHeap::entry_cleanup() {
2844 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2845
2846 static const char* msg = "Concurrent cleanup";
2847 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2848 EventMark em("%s", msg);
2849
2850 // This phase does not use workers, no need for setup
2851
2852 try_inject_alloc_failure();
2853 op_cleanup();
2854 }
2855
2856 void ShenandoahHeap::entry_cleanup_traversal() {
2857 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2858
2859 static const char* msg = "Concurrent cleanup";
2860 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2861 EventMark em("%s", msg);
2862
2863 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2864
2865 try_inject_alloc_failure();
2866 op_cleanup_traversal();
2867 }
2868
2869 void ShenandoahHeap::entry_cleanup_bitmaps() {
2870 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2871
2872 static const char* msg = "Concurrent cleanup";
2873 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2874 EventMark em("%s", msg);
2875
2876 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup());
2877
2878 try_inject_alloc_failure();
2879 op_cleanup_bitmaps();
2880 }
2881
2882 void ShenandoahHeap::entry_preclean() {
2883 if (ShenandoahPreclean && process_references()) {
2884 static const char* msg = "Concurrent precleaning";
2885 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2886 EventMark em("%s", msg);
2887
2888 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2889
2890 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_preclean());
2891
2892 try_inject_alloc_failure();
2893 op_preclean();
2894 }
2895 }
2896
2897 void ShenandoahHeap::entry_traversal() {
2898 static const char* msg = "Concurrent traversal";
2899 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2900 EventMark em("%s", msg);
2901
2902 TraceCollectorStats tcs(is_minor_gc() ? monitoring_support()->partial_collection_counters()
2903 : monitoring_support()->concurrent_collection_counters());
2904
2905 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2906
2907 try_inject_alloc_failure();
2908 op_traversal();
2909 }
2910
2911 void ShenandoahHeap::try_inject_alloc_failure() {
2912 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2913 _inject_alloc_failure.set();
2914 os::naked_short_sleep(1);
2915 if (cancelled_gc()) {
2916 log_info(gc)("Allocation failure was successfully injected");
2917 }
2918 }
2919 }
2920
2921 bool ShenandoahHeap::should_inject_alloc_failure() {
2922 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2923 }
2924
2925 void ShenandoahHeap::initialize_serviceability() {
2926 _memory_pool = new ShenandoahMemoryPool(this);
2927 _cycle_memory_manager.add_pool(_memory_pool);
2928 _stw_memory_manager.add_pool(_memory_pool);
2929 }
2930
2931 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2932 GrowableArray<GCMemoryManager*> memory_managers(2);
2933 memory_managers.append(&_cycle_memory_manager);
2934 memory_managers.append(&_stw_memory_manager);
2935 return memory_managers;
2936 }
2937
2938 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2939 GrowableArray<MemoryPool*> memory_pools(1);
2940 memory_pools.append(_memory_pool);
2941 return memory_pools;
2942 }
2943
2944 void ShenandoahHeap::enter_evacuation() {
2945 _oom_evac_handler.enter_evacuation();
2946 }
2947
2948 void ShenandoahHeap::leave_evacuation() {
2949 _oom_evac_handler.leave_evacuation();
2950 }
2951
2952 SoftRefPolicy* ShenandoahHeap::soft_ref_policy() {
2953 return &_soft_ref_policy;
2954 }
2955
2956 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2957 _index(0),
2958 _heap(ShenandoahHeap::heap()) {}
2959
2960 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2961 _index(0),
2962 _heap(heap) {}
2963
2964 void ShenandoahRegionIterator::reset() {
2965 _index = 0;
2966 }
2967
2968 bool ShenandoahRegionIterator::has_next() const {
2969 return _index < _heap->num_regions();
2970 }
2971
2972 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
2973 ShenandoahRegionIterator regions;
2974 ShenandoahHeapRegion* r = regions.next();
2975 while (r != NULL) {
2976 if (cl.heap_region_do(r)) {
2977 break;
2978 }
2979 r = regions.next();
2980 }
2981 }
2982
2983 bool ShenandoahHeap::is_minor_gc() const {
2984 return _gc_cycle_mode.get() == MINOR;
2985 }
2986
2987 bool ShenandoahHeap::is_major_gc() const {
2988 return _gc_cycle_mode.get() == MAJOR;
2989 }
2990
2991 void ShenandoahHeap::set_cycle_mode(GCCycleMode gc_cycle_mode) {
2992 _gc_cycle_mode.set(gc_cycle_mode);
2993 }
2994
2995 char ShenandoahHeap::gc_state() const {
2996 return _gc_state.raw_value();
2997 }
2998
2999 void ShenandoahHeap::deduplicate_string(oop str) {
3000 assert(java_lang_String::is_instance(str), "invariant");
3001
3002 if (ShenandoahStringDedup::is_enabled()) {
3003 ShenandoahStringDedup::deduplicate(str);
3004 }
3005 }