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