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