1 /*
2 * Copyright (c) 2013, 2017, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/parallelCleaning.hpp"
30
31 #include "gc/shenandoah/brooksPointer.hpp"
32 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
33 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
38 #include "gc/shenandoah/shenandoahControlThread.hpp"
39 #include "gc/shenandoah/shenandoahFreeSet.hpp"
40 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
41 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
42 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
43 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
44 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
45 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
46 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
47 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
48 #include "gc/shenandoah/shenandoahPacer.hpp"
49 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
50 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
51 #include "gc/shenandoah/shenandoahStringDedup.hpp"
52 #include "gc/shenandoah/shenandoahUtils.hpp"
53 #include "gc/shenandoah/shenandoahVerifier.hpp"
54 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
55 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
56 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
57
58 #include "runtime/vmThread.hpp"
59 #include "services/mallocTracker.hpp"
60
61 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
62
63 #ifdef ASSERT
64 template <class T>
65 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
66 T o = oopDesc::load_heap_oop(p);
67 if (! oopDesc::is_null(o)) {
68 oop obj = oopDesc::decode_heap_oop_not_null(o);
69 shenandoah_assert_not_forwarded(p, obj);
70 }
71 }
72
73 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
74 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
75 #endif
76
77 const char* ShenandoahHeap::name() const {
78 return "Shenandoah";
79 }
80
81 class ShenandoahPretouchTask : public AbstractGangTask {
82 private:
83 ShenandoahRegionIterator _regions;
84 const size_t _bitmap_size;
85 const size_t _page_size;
86 char* _bitmap0_base;
87 char* _bitmap1_base;
88 public:
89 ShenandoahPretouchTask(char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
90 size_t page_size) :
91 AbstractGangTask("Shenandoah PreTouch",
92 Universe::is_fully_initialized() ? GCId::current_raw() :
93 // During VM initialization there is
94 // no GC cycle that this task can be
95 // associated with.
96 GCId::undefined()),
97 _bitmap0_base(bitmap0_base),
98 _bitmap1_base(bitmap1_base),
99 _bitmap_size(bitmap_size),
100 _page_size(page_size) {}
101
102 virtual void work(uint worker_id) {
103 ShenandoahHeapRegion* r = _regions.next();
104 while (r != NULL) {
105 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
106 r->region_number(), p2i(r->bottom()), p2i(r->end()));
107 os::pretouch_memory(r->bottom(), r->end(), _page_size);
108
109 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
110 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
111 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
112
113 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
114 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
115 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
116
117 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
118 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
119 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
120
121 r = _regions.next();
122 }
123 }
124 };
125
126 jint ShenandoahHeap::initialize() {
127 CollectedHeap::pre_initialize();
128
129 BrooksPointer::initial_checks();
130
131 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
132 size_t max_byte_size = collector_policy()->max_heap_byte_size();
133 size_t heap_alignment = collector_policy()->heap_alignment();
134
135 if (ShenandoahAlwaysPreTouch) {
136 // Enabled pre-touch means the entire heap is committed right away.
137 init_byte_size = max_byte_size;
138 }
139
140 Universe::check_alignment(max_byte_size,
141 ShenandoahHeapRegion::region_size_bytes(),
142 "shenandoah heap");
143 Universe::check_alignment(init_byte_size,
144 ShenandoahHeapRegion::region_size_bytes(),
145 "shenandoah heap");
146
147 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
148 heap_alignment);
149 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
150
151 set_barrier_set(new ShenandoahBarrierSet(this));
152 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
153
154 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
155 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
156 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
157 _committed = _initial_size;
158
159 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
160 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
161 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
162 }
163
164 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
165 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
166
167 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
168 _free_set = new ShenandoahFreeSet(this, _num_regions);
169
170 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
171
172 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
173 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
174 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
175
176 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
177 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
178 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
179
180 if (ShenandoahPacing) {
181 _pacer = new ShenandoahPacer(this);
182 _pacer->setup_for_idle();
183 } else {
184 _pacer = NULL;
185 }
186
187 {
188 ShenandoahHeapLocker locker(lock());
189 for (size_t i = 0; i < _num_regions; i++) {
190 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
191 (HeapWord*) pgc_rs.base() + reg_size_words * i,
192 reg_size_words,
193 i,
194 i < num_committed_regions);
195
196 _complete_top_at_mark_starts_base[i] = r->bottom();
197 _next_top_at_mark_starts_base[i] = r->bottom();
198 _regions[i] = r;
199 assert(!collection_set()->is_in(i), "New region should not be in collection set");
200 }
201
202 _free_set->rebuild();
203 }
204
205 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
206 "misaligned heap: "PTR_FORMAT, p2i(base()));
207
208 // The call below uses stuff (the SATB* things) that are in G1, but probably
209 // belong into a shared location.
210 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
211 SATB_Q_FL_lock,
212 20 /*G1SATBProcessCompletedThreshold */,
213 Shared_SATB_Q_lock);
214
215 // Reserve space for prev and next bitmap.
216 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
217 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
218 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
219 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
220
221 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
222
223 guarantee(bitmap_bytes_per_region != 0,
224 "Bitmap bytes per region should not be zero");
225 guarantee(is_power_of_2(bitmap_bytes_per_region),
226 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
227
228 if (bitmap_page_size > bitmap_bytes_per_region) {
229 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
230 _bitmap_bytes_per_slice = bitmap_page_size;
231 } else {
232 _bitmap_regions_per_slice = 1;
233 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
234 }
235
236 guarantee(_bitmap_regions_per_slice >= 1,
237 "Should have at least one region per slice: " SIZE_FORMAT,
238 _bitmap_regions_per_slice);
239
240 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
241 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
242 _bitmap_bytes_per_slice, bitmap_page_size);
243
244 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
245 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
246 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
247
248 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
249 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
250 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
251
252 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
253 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
254 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
255 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
256 "couldn't allocate initial bitmap");
257 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
258 "couldn't allocate initial bitmap");
259
260 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
261
262 if (ShenandoahVerify) {
263 ReservedSpace verify_bitmap(_bitmap_size, page_size);
264 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
265 "couldn't allocate verification bitmap");
266 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
267 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
268 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
269 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
270 }
271
272 if (ShenandoahAlwaysPreTouch) {
273 assert (!AlwaysPreTouch, "Should have been overridden");
274
275 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
276 // before initialize() below zeroes it with initializing thread. For any given region,
277 // we touch the region and the corresponding bitmaps from the same thread.
278
279 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
280 _num_regions, page_size);
281 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
282 _workers->run_task(&cl);
283 }
284
285 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
286 _complete_mark_bit_map = &_mark_bit_map0;
287
288 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
289 _next_mark_bit_map = &_mark_bit_map1;
290
291 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
292 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
293 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
294 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
295 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
296
297 if (UseShenandoahMatrix) {
298 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
299 } else {
300 _connection_matrix = NULL;
301 }
302
303 _traversal_gc = _shenandoah_policy->can_do_traversal_gc() ?
304 new ShenandoahTraversalGC(this, _num_regions) :
305 NULL;
306
307 _monitoring_support = new ShenandoahMonitoringSupport(this);
308
309 _phase_timings = new ShenandoahPhaseTimings();
310
311 if (ShenandoahAllocationTrace) {
312 _alloc_tracker = new ShenandoahAllocTracker();
313 }
314
315 ShenandoahStringDedup::initialize();
316
317 _control_thread = new ShenandoahControlThread();
318
319 ShenandoahCodeRoots::initialize();
320
321 LogTarget(Trace, gc, region) lt;
322 if (lt.is_enabled()) {
323 ResourceMark rm;
324 LogStream ls(lt);
325 log_trace(gc, region)("All Regions");
326 print_heap_regions_on(&ls);
327 log_trace(gc, region)("Free Regions");
328 _free_set->print_on(&ls);
329 }
330
331 log_info(gc, init)("Safepointing mechanism: %s",
332 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
333 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
334
335 return JNI_OK;
336 }
337
338 #ifdef _MSC_VER
339 #pragma warning( push )
340 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
341 #endif
342
343 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
344 CollectedHeap(),
345 _shenandoah_policy(policy),
346 _regions(NULL),
347 _free_set(NULL),
348 _collection_set(NULL),
349 _update_refs_iterator(this),
350 _bytes_allocated_since_gc_start(0),
351 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
352 _ref_processor(NULL),
353 _next_top_at_mark_starts(NULL),
354 _next_top_at_mark_starts_base(NULL),
355 _complete_top_at_mark_starts(NULL),
356 _complete_top_at_mark_starts_base(NULL),
357 _mark_bit_map0(),
358 _mark_bit_map1(),
359 _aux_bit_map(),
360 _connection_matrix(NULL),
361 _verifier(NULL),
362 _pacer(NULL),
363 _used_at_last_gc(0),
364 _alloc_seq_at_last_gc_start(0),
365 _alloc_seq_at_last_gc_end(0),
366 _safepoint_workers(NULL),
367 _gc_cycle_mode(),
368 #ifdef ASSERT
369 _heap_expansion_count(0),
370 #endif
371 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
372 _phase_timings(NULL),
373 _alloc_tracker(NULL),
374 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
375 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
376 _memory_pool(NULL)
377 {
378 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
379 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
380 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
381
382 _scm = new ShenandoahConcurrentMark();
383 _full_gc = new ShenandoahMarkCompact();
384 _used = 0;
385
386 _max_workers = MAX2(_max_workers, 1U);
387 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
388 /* are_GC_task_threads */true,
389 /* are_ConcurrentGC_threads */false);
390 if (_workers == NULL) {
391 vm_exit_during_initialization("Failed necessary allocation.");
392 } else {
393 _workers->initialize_workers();
394 }
395
396 if (ParallelSafepointCleanupThreads > 1) {
397 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
398 ParallelSafepointCleanupThreads,
399 false, false);
400 _safepoint_workers->initialize_workers();
401 }
402 }
403
404 #ifdef _MSC_VER
405 #pragma warning( pop )
406 #endif
407
408 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
409 private:
410 ShenandoahRegionIterator _regions;
411
412 public:
413 ShenandoahResetNextBitmapTask() :
414 AbstractGangTask("Parallel Reset Bitmap Task") {}
415
416 void work(uint worker_id) {
417 ShenandoahHeapRegion* region = _regions.next();
418 ShenandoahHeap* heap = ShenandoahHeap::heap();
419 while (region != NULL) {
420 if (heap->is_bitmap_slice_committed(region)) {
421 HeapWord* bottom = region->bottom();
422 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
423 if (top > bottom) {
424 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
425 }
426 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
427 }
428 region = _regions.next();
429 }
430 }
431 };
432
433 void ShenandoahHeap::reset_next_mark_bitmap() {
434 assert_gc_workers(_workers->active_workers());
435
436 ShenandoahResetNextBitmapTask task;
437 _workers->run_task(&task);
438 }
439
440 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
441 private:
442 ShenandoahRegionIterator _regions;
443
444 public:
445 ShenandoahResetNextBitmapTraversalTask() :
446 AbstractGangTask("Parallel Reset Bitmap Task for Traversal") {}
447
448 void work(uint worker_id) {
449 ShenandoahHeap* heap = ShenandoahHeap::heap();
450 ShenandoahHeapRegionSet* traversal_set = heap->traversal_gc()->traversal_set();
451 ShenandoahHeapRegion* region = _regions.next();
452 while (region != NULL) {
453 if (heap->is_bitmap_slice_committed(region)) {
454 if (traversal_set->is_in(region) && !region->is_trash()) {
455 ShenandoahHeapLocker locker(heap->lock());
456 HeapWord* bottom = region->bottom();
457 HeapWord* top = heap->next_top_at_mark_start(bottom);
458 assert(top <= region->top(),
459 "TAMS must smaller/equals than top: TAMS: "PTR_FORMAT", top: "PTR_FORMAT,
460 p2i(top), p2i(region->top()));
461 if (top > bottom) {
462 heap->complete_mark_bit_map()->copy_from(heap->next_mark_bit_map(), MemRegion(bottom, top));
463 heap->set_complete_top_at_mark_start(bottom, top);
464 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
465 heap->set_next_top_at_mark_start(bottom, bottom);
466 }
467 }
468 assert(heap->is_next_bitmap_clear_range(region->bottom(), region->end()),
469 "need clear next bitmap");
470 }
471 region = _regions.next();
472 }
473 }
474 };
475
476 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
477 assert_gc_workers(_workers->active_workers());
478
479 ShenandoahResetNextBitmapTraversalTask task;
480 _workers->run_task(&task);
481 }
482
483 bool ShenandoahHeap::is_next_bitmap_clear() {
484 for (size_t idx = 0; idx < _num_regions; idx++) {
485 ShenandoahHeapRegion* r = get_region(idx);
486 if (is_bitmap_slice_committed(r) && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
487 return false;
488 }
489 }
490 return true;
491 }
492
493 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
494 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
495 }
496
497 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
498 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
499 }
500
501 void ShenandoahHeap::print_on(outputStream* st) const {
502 st->print_cr("Shenandoah Heap");
503 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
504 capacity() / K, committed() / K, used() / K);
505 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
506 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
507
508 st->print("Status: ");
509 if (has_forwarded_objects()) st->print("has forwarded objects, ");
510 if (is_concurrent_mark_in_progress()) st->print("marking, ");
511 if (is_evacuation_in_progress()) st->print("evacuating, ");
512 if (is_update_refs_in_progress()) st->print("updating refs, ");
513 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
514 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
515 if (is_full_gc_in_progress()) st->print("full gc, ");
516 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
517
518 if (cancelled_concgc()) {
519 st->print("conc gc cancelled");
520 } else {
521 st->print("not cancelled");
522 }
523 st->cr();
524
525 st->print_cr("Reserved region:");
526 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
527 p2i(reserved_region().start()),
528 p2i(reserved_region().end()));
529
530 if (UseShenandoahMatrix) {
531 st->print_cr("Matrix:");
532
533 ShenandoahConnectionMatrix* matrix = connection_matrix();
534 if (matrix != NULL) {
535 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
536 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
537 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
538 } else {
539 st->print_cr(" No matrix.");
540 }
541 }
542
543 if (Verbose) {
544 print_heap_regions_on(st);
545 }
546 }
547
548 class ShenandoahInitGCLABClosure : public ThreadClosure {
549 public:
550 void do_thread(Thread* thread) {
551 thread->gclab().initialize(true);
552 }
553 };
554
555 void ShenandoahHeap::post_initialize() {
556 CollectedHeap::post_initialize();
557 if (UseTLAB) {
558 MutexLocker ml(Threads_lock);
559
560 ShenandoahInitGCLABClosure init_gclabs;
561 Threads::java_threads_do(&init_gclabs);
562 gc_threads_do(&init_gclabs);
563
564 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
565 // Now, we will let WorkGang to initialize gclab when new worker is created.
566 _workers->set_initialize_gclab();
567 }
568
569 _scm->initialize(_max_workers);
570 _full_gc->initialize(_gc_timer);
571
572 ref_processing_init();
573
574 _shenandoah_policy->post_heap_initialize();
575 }
576
577 size_t ShenandoahHeap::used() const {
578 return OrderAccess::load_acquire(&_used);
579 }
580
581 size_t ShenandoahHeap::committed() const {
582 OrderAccess::acquire();
583 return _committed;
584 }
585
586 void ShenandoahHeap::increase_committed(size_t bytes) {
587 assert_heaplock_or_safepoint();
588 _committed += bytes;
589 }
590
591 void ShenandoahHeap::decrease_committed(size_t bytes) {
592 assert_heaplock_or_safepoint();
593 _committed -= bytes;
594 }
595
596 void ShenandoahHeap::increase_used(size_t bytes) {
597 Atomic::add(bytes, &_used);
598 }
599
600 void ShenandoahHeap::set_used(size_t bytes) {
601 OrderAccess::release_store_fence(&_used, bytes);
602 }
603
604 void ShenandoahHeap::decrease_used(size_t bytes) {
605 assert(used() >= bytes, "never decrease heap size by more than we've left");
606 Atomic::sub(bytes, &_used);
607 }
608
609 void ShenandoahHeap::increase_allocated(size_t bytes) {
610 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
611 }
612
613 void ShenandoahHeap::notify_alloc(size_t words, bool waste) {
614 size_t bytes = words * HeapWordSize;
615 if (!waste) {
616 increase_used(bytes);
617 }
618 increase_allocated(bytes);
619 if (ShenandoahPacing) {
620 control_thread()->pacing_notify_alloc(words);
621 if (waste) {
622 pacer()->claim_for_alloc(words, true);
623 }
624 }
625 }
626
627 size_t ShenandoahHeap::capacity() const {
628 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
629 }
630
631 bool ShenandoahHeap::is_maximal_no_gc() const {
632 Unimplemented();
633 return true;
634 }
635
636 size_t ShenandoahHeap::max_capacity() const {
637 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
638 }
639
640 size_t ShenandoahHeap::initial_capacity() const {
641 return _initial_size;
642 }
643
644 bool ShenandoahHeap::is_in(const void* p) const {
645 HeapWord* heap_base = (HeapWord*) base();
646 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
647 return p >= heap_base && p < last_region_end;
648 }
649
650 bool ShenandoahHeap::is_scavengable(oop p) {
651 return true;
652 }
653
654 void ShenandoahHeap::handle_heap_shrinkage(double shrink_before) {
655 if (!ShenandoahUncommit) {
656 return;
657 }
658
659 ShenandoahHeapLocker locker(lock());
660
661 size_t count = 0;
662 for (size_t i = 0; i < num_regions(); i++) {
663 ShenandoahHeapRegion* r = get_region(i);
664 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
665 r->make_uncommitted();
666 count++;
667 }
668 }
669
670 if (count > 0) {
671 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
672 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
673 _control_thread->notify_heap_changed();
674 }
675 }
676
677 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
678 // Retain tlab and allocate object in shared space if
679 // the amount free in the tlab is too large to discard.
680 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
681 thread->gclab().record_slow_allocation(size);
682 return NULL;
683 }
684
685 // Discard gclab and allocate a new one.
686 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
687 size_t new_gclab_size = thread->gclab().compute_size(size);
688
689 thread->gclab().clear_before_allocation();
690
691 if (new_gclab_size == 0) {
692 return NULL;
693 }
694
695 // Allocate a new GCLAB...
696 HeapWord* obj = allocate_new_gclab(new_gclab_size);
697 if (obj == NULL) {
698 return NULL;
699 }
700
701 if (ZeroTLAB) {
702 // ..and clear it.
703 Copy::zero_to_words(obj, new_gclab_size);
704 } else {
705 // ...and zap just allocated object.
706 #ifdef ASSERT
707 // Skip mangling the space corresponding to the object header to
708 // ensure that the returned space is not considered parsable by
709 // any concurrent GC thread.
710 size_t hdr_size = oopDesc::header_size();
711 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
712 #endif // ASSERT
713 }
714 thread->gclab().fill(obj, obj + size, new_gclab_size);
715 return obj;
716 }
717
718 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
719 #ifdef ASSERT
720 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
721 #endif
722 return allocate_new_lab(word_size, _alloc_tlab);
723 }
724
725 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
726 #ifdef ASSERT
727 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
728 #endif
729 return allocate_new_lab(word_size, _alloc_gclab);
730 }
731
732 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
733 HeapWord* result = allocate_memory(word_size, type);
734
735 if (result != NULL) {
736 assert(! in_collection_set(result), "Never allocate in collection set");
737
738 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
739
740 }
741 return result;
742 }
743
744 ShenandoahHeap* ShenandoahHeap::heap() {
745 CollectedHeap* heap = Universe::heap();
746 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
747 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
748 return (ShenandoahHeap*) heap;
749 }
750
751 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
752 CollectedHeap* heap = Universe::heap();
753 return (ShenandoahHeap*) heap;
754 }
755
756 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
757 ShenandoahAllocTrace trace_alloc(word_size, type);
758
759 bool in_new_region = false;
760 HeapWord* result = NULL;
761
762 if (type == _alloc_tlab || type == _alloc_shared) {
763 if (ShenandoahPacing) {
764 pacer()->pace_for_alloc(word_size);
765 }
766
767 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
768 result = allocate_memory_under_lock(word_size, type, in_new_region);
769 }
770
771 // Allocation failed, try full-GC, then retry allocation.
772 //
773 // It might happen that one of the threads requesting allocation would unblock
774 // way later after full-GC happened, only to fail the second allocation, because
775 // other threads have already depleted the free storage. In this case, a better
776 // strategy would be to try full-GC again.
777 //
778 // Lacking the way to detect progress from "collect" call, we are left with blindly
779 // retrying for some bounded number of times.
780 // TODO: Poll if Full GC made enough progress to warrant retry.
781 int tries = 0;
782 while ((result == NULL) && (tries++ < ShenandoahAllocGCTries)) {
783 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing GC, try %d",
784 p2i(Thread::current()), word_size * HeapWordSize, tries);
785 control_thread()->handle_alloc_failure(word_size);
786 result = allocate_memory_under_lock(word_size, type, in_new_region);
787 }
788 } else {
789 assert(type == _alloc_gclab || type == _alloc_shared_gc, "Can only accept these types here");
790 result = allocate_memory_under_lock(word_size, type, in_new_region);
791 // Do not call handle_alloc_failure() here, because we cannot block.
792 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
793 }
794
795 if (in_new_region) {
796 control_thread()->notify_heap_changed();
797 }
798
799 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
800 word_size, p2i(result), Thread::current()->osthread()->thread_id());
801
802 if (result != NULL) {
803 notify_alloc(word_size, false);
804 }
805
806 return result;
807 }
808
809 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
810 ShenandoahHeapLocker locker(lock());
811 return _free_set->allocate(word_size, type, in_new_region);
812 }
813
814 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
815 bool* gc_overhead_limit_was_exceeded) {
816 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
817 HeapWord* result = filler + BrooksPointer::word_size();
818 if (filler != NULL) {
819 BrooksPointer::initialize(oop(result));
820
821 assert(! in_collection_set(result), "never allocate in targetted region");
822 return result;
823 } else {
824 return NULL;
825 }
826 }
827
828 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
829 private:
830 ShenandoahHeap* _heap;
831 Thread* _thread;
832 public:
833 ShenandoahEvacuateUpdateRootsClosure() :
834 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
835 }
836
837 private:
838 template <class T>
839 void do_oop_work(T* p) {
840 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
841
842 T o = oopDesc::load_heap_oop(p);
843 if (! oopDesc::is_null(o)) {
844 oop obj = oopDesc::decode_heap_oop_not_null(o);
845 if (_heap->in_collection_set(obj)) {
846 shenandoah_assert_marked_complete(p, obj);
847 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
848 if (oopDesc::unsafe_equals(resolved, obj)) {
849 resolved = _heap->evacuate_object(obj, _thread);
850 }
851 oopDesc::encode_store_heap_oop(p, resolved);
852 }
853 }
854 }
855
856 public:
857 void do_oop(oop* p) {
858 do_oop_work(p);
859 }
860 void do_oop(narrowOop* p) {
861 do_oop_work(p);
862 }
863 };
864
865 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
866 private:
867 ShenandoahHeap* _heap;
868 Thread* _thread;
869 public:
870 ShenandoahEvacuateRootsClosure() :
871 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
872 }
873
874 private:
875 template <class T>
876 void do_oop_work(T* p) {
877 T o = oopDesc::load_heap_oop(p);
878 if (! oopDesc::is_null(o)) {
879 oop obj = oopDesc::decode_heap_oop_not_null(o);
880 if (_heap->in_collection_set(obj)) {
881 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
882 if (oopDesc::unsafe_equals(resolved, obj)) {
883 _heap->evacuate_object(obj, _thread);
884 }
885 }
886 }
887 }
888
889 public:
890 void do_oop(oop* p) {
891 do_oop_work(p);
892 }
893 void do_oop(narrowOop* p) {
894 do_oop_work(p);
895 }
896 };
897
898 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
899 private:
900 ShenandoahHeap* const _heap;
901 Thread* const _thread;
902 public:
903 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
904 _heap(heap), _thread(Thread::current()) {}
905
906 void do_object(oop p) {
907 shenandoah_assert_marked_complete(NULL, p);
908 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
909 _heap->evacuate_object(p, _thread);
910 }
911 }
912 };
913
914 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
915 private:
916 ShenandoahHeap* const _sh;
917 ShenandoahCollectionSet* const _cs;
918 ShenandoahSharedFlag _claimed_codecache;
919
920 public:
921 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
922 ShenandoahCollectionSet* cs) :
923 AbstractGangTask("Parallel Evacuation Task"),
924 _cs(cs),
925 _sh(sh)
926 {}
927
928 void work(uint worker_id) {
929
930 ShenandoahEvacOOMScope oom_evac_scope;
931 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
932
933 // If concurrent code cache evac is enabled, evacuate it here.
934 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
935 // nmethods. The update would be handled elsewhere.
936 if (ShenandoahConcurrentEvacCodeRoots && _claimed_codecache.try_set()) {
937 ShenandoahEvacuateRootsClosure cl;
938 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
939 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
940 CodeCache::blobs_do(&blobs);
941 }
942
943 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
944 ShenandoahHeapRegion* r;
945 while ((r =_cs->claim_next()) != NULL) {
946 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
947 worker_id,
948 r->region_number());
949
950 assert(r->has_live(), "all-garbage regions are reclaimed early");
951 _sh->marked_object_iterate(r, &cl);
952
953 if (_sh->check_cancelled_concgc_and_yield()) {
954 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
955 break;
956 }
957
958 if (ShenandoahPacing) {
959 _sh->pacer()->report_evac(r->get_live_data_words());
960 }
961 }
962 }
963 };
964
965 void ShenandoahHeap::trash_cset_regions() {
966 ShenandoahHeapLocker locker(lock());
967
968 ShenandoahCollectionSet* set = collection_set();
969 ShenandoahHeapRegion* r;
970 set->clear_current_index();
971 while ((r = set->next()) != NULL) {
972 r->make_trash();
973 }
974 collection_set()->clear();
975 }
976
977 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
978 st->print_cr("Heap Regions:");
979 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
980 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
981 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
982 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
983
984 for (size_t i = 0; i < num_regions(); i++) {
985 get_region(i)->print_on(st);
986 }
987 }
988
989 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
990 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
991
992 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
993 size_t size = humongous_obj->size() + BrooksPointer::word_size();
994 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
995 size_t index = start->region_number() + required_regions - 1;
996
997 assert(!start->has_live(), "liveness must be zero");
998 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
999
1000 for(size_t i = 0; i < required_regions; i++) {
1001 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1002 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1003 ShenandoahHeapRegion* region = get_region(index --);
1004
1005 LogTarget(Trace, gc, humongous) lt;
1006 if (lt.is_enabled()) {
1007 ResourceMark rm;
1008 LogStream ls(lt);
1009 region->print_on(&ls);
1010 }
1011
1012 assert(region->is_humongous(), "expect correct humongous start or continuation");
1013 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1014
1015 region->make_trash();
1016 }
1017 }
1018
1019 #ifdef ASSERT
1020 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1021 bool heap_region_do(ShenandoahHeapRegion* r) {
1022 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1023 return false;
1024 }
1025 };
1026 #endif
1027
1028 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1029 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1030
1031 if (!cancelled_concgc()) {
1032 // Allocations might have happened before we STWed here, record peak:
1033 shenandoahPolicy()->record_peak_occupancy();
1034
1035 make_tlabs_parsable(true);
1036
1037 if (ShenandoahVerify) {
1038 verifier()->verify_after_concmark();
1039 }
1040
1041 trash_cset_regions();
1042
1043 // NOTE: This needs to be done during a stop the world pause, because
1044 // putting regions into the collection set concurrently with Java threads
1045 // will create a race. In particular, acmp could fail because when we
1046 // resolve the first operand, the containing region might not yet be in
1047 // the collection set, and thus return the original oop. When the 2nd
1048 // operand gets resolved, the region could be in the collection set
1049 // and the oop gets evacuated. If both operands have originally been
1050 // the same, we get false negatives.
1051
1052 {
1053 ShenandoahHeapLocker locker(lock());
1054 _collection_set->clear();
1055 _free_set->clear();
1056
1057 #ifdef ASSERT
1058 ShenandoahCheckCollectionSetClosure ccsc;
1059 heap_region_iterate(&ccsc);
1060 #endif
1061
1062 _shenandoah_policy->choose_collection_set(_collection_set);
1063
1064 _free_set->rebuild();
1065 }
1066
1067 Universe::update_heap_info_at_gc();
1068
1069 if (ShenandoahVerify) {
1070 verifier()->verify_before_evacuation();
1071 }
1072 }
1073 }
1074
1075
1076 class ShenandoahRetireTLABClosure : public ThreadClosure {
1077 private:
1078 bool _retire;
1079
1080 public:
1081 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1082
1083 void do_thread(Thread* thread) {
1084 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1085 thread->gclab().make_parsable(_retire);
1086 }
1087 };
1088
1089 void ShenandoahHeap::make_tlabs_parsable(bool retire_tlabs) {
1090 if (UseTLAB) {
1091 CollectedHeap::ensure_parsability(retire_tlabs);
1092 ShenandoahRetireTLABClosure cl(retire_tlabs);
1093 Threads::java_threads_do(&cl);
1094 gc_threads_do(&cl);
1095 }
1096 }
1097
1098
1099 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1100 ShenandoahRootEvacuator* _rp;
1101 public:
1102
1103 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1104 AbstractGangTask("Shenandoah evacuate and update roots"),
1105 _rp(rp)
1106 {
1107 // Nothing else to do.
1108 }
1109
1110 void work(uint worker_id) {
1111 ShenandoahEvacOOMScope oom_evac_scope;
1112 ShenandoahEvacuateUpdateRootsClosure cl;
1113
1114 if (ShenandoahConcurrentEvacCodeRoots) {
1115 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1116 } else {
1117 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1118 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1119 }
1120 }
1121 };
1122
1123 class ShenandoahFixRootsTask : public AbstractGangTask {
1124 ShenandoahRootEvacuator* _rp;
1125 public:
1126
1127 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1128 AbstractGangTask("Shenandoah update roots"),
1129 _rp(rp)
1130 {
1131 // Nothing else to do.
1132 }
1133
1134 void work(uint worker_id) {
1135 ShenandoahEvacOOMScope oom_evac_scope;
1136 ShenandoahUpdateRefsClosure cl;
1137 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1138
1139 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1140 }
1141 };
1142
1143 void ShenandoahHeap::evacuate_and_update_roots() {
1144
1145 #if defined(COMPILER2) || INCLUDE_JVMCI
1146 DerivedPointerTable::clear();
1147 #endif
1148 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1149
1150 {
1151 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1152 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1153 workers()->run_task(&roots_task);
1154 }
1155
1156 #if defined(COMPILER2) || INCLUDE_JVMCI
1157 DerivedPointerTable::update_pointers();
1158 #endif
1159 if (cancelled_concgc()) {
1160 fixup_roots();
1161 }
1162 }
1163
1164 void ShenandoahHeap::fixup_roots() {
1165 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1166
1167 // If initial evacuation has been cancelled, we need to update all references
1168 // after all workers have finished. Otherwise we might run into the following problem:
1169 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1170 // GC thread 2 evacuates the same object X to to-space
1171 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1172 // clear() and update_pointers() must always be called in pairs,
1173 // cannot nest with above clear()/update_pointers().
1174 #if defined(COMPILER2) || INCLUDE_JVMCI
1175 DerivedPointerTable::clear();
1176 #endif
1177 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1178 ShenandoahFixRootsTask update_roots_task(&rp);
1179 workers()->run_task(&update_roots_task);
1180 #if defined(COMPILER2) || INCLUDE_JVMCI
1181 DerivedPointerTable::update_pointers();
1182 #endif
1183 }
1184
1185 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1186 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1187
1188 CodeBlobToOopClosure blobsCl(cl, false);
1189 CLDToOopClosure cldCl(cl);
1190
1191 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1192 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1193 }
1194
1195 bool ShenandoahHeap::supports_tlab_allocation() const {
1196 return true;
1197 }
1198
1199 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1200 return MIN2(_free_set->unsafe_peek_free(), max_tlab_size());
1201 }
1202
1203 size_t ShenandoahHeap::max_tlab_size() const {
1204 return ShenandoahHeapRegion::max_tlab_size_bytes();
1205 }
1206
1207 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1208 public:
1209 void do_thread(Thread* thread) {
1210 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1211 thread->gclab().resize();
1212 }
1213 };
1214
1215 void ShenandoahHeap::resize_all_tlabs() {
1216 CollectedHeap::resize_all_tlabs();
1217
1218 ShenandoahResizeGCLABClosure cl;
1219 Threads::java_threads_do(&cl);
1220 gc_threads_do(&cl);
1221 }
1222
1223 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1224 public:
1225 void do_thread(Thread* thread) {
1226 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1227 thread->gclab().accumulate_statistics();
1228 thread->gclab().initialize_statistics();
1229 }
1230 };
1231
1232 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1233 ShenandoahAccumulateStatisticsGCLABClosure cl;
1234 Threads::java_threads_do(&cl);
1235 gc_threads_do(&cl);
1236 }
1237
1238 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1239 return true;
1240 }
1241
1242 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1243 // Overridden to do nothing.
1244 return new_obj;
1245 }
1246
1247 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1248 return true;
1249 }
1250
1251 bool ShenandoahHeap::card_mark_must_follow_store() const {
1252 return false;
1253 }
1254
1255 void ShenandoahHeap::collect(GCCause::Cause cause) {
1256 _control_thread->handle_explicit_gc(cause);
1257 }
1258
1259 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1260 //assert(false, "Shouldn't need to do full collections");
1261 }
1262
1263 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1264 Unimplemented();
1265 return NULL;
1266
1267 }
1268
1269 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1270 return _shenandoah_policy;
1271 }
1272
1273
1274 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1275 Space* sp = heap_region_containing(addr);
1276 if (sp != NULL) {
1277 return sp->block_start(addr);
1278 }
1279 return NULL;
1280 }
1281
1282 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1283 Space* sp = heap_region_containing(addr);
1284 assert(sp != NULL, "block_size of address outside of heap");
1285 return sp->block_size(addr);
1286 }
1287
1288 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1289 Space* sp = heap_region_containing(addr);
1290 return sp->block_is_obj(addr);
1291 }
1292
1293 jlong ShenandoahHeap::millis_since_last_gc() {
1294 return 0;
1295 }
1296
1297 void ShenandoahHeap::prepare_for_verify() {
1298 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1299 make_tlabs_parsable(false);
1300 }
1301 }
1302
1303 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1304 workers()->print_worker_threads_on(st);
1305 if (ShenandoahStringDedup::is_enabled()) {
1306 ShenandoahStringDedup::print_worker_threads_on(st);
1307 }
1308 }
1309
1310 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1311 workers()->threads_do(tcl);
1312 if (ShenandoahStringDedup::is_enabled()) {
1313 ShenandoahStringDedup::threads_do(tcl);
1314 }
1315 }
1316
1317 void ShenandoahHeap::print_tracing_info() const {
1318 LogTarget(Info, gc, stats) lt;
1319 if (lt.is_enabled()) {
1320 ResourceMark rm;
1321 LogStream ls(lt);
1322
1323 phase_timings()->print_on(&ls);
1324
1325 ls.cr();
1326 ls.cr();
1327
1328 shenandoahPolicy()->print_gc_stats(&ls);
1329
1330 ls.cr();
1331 ls.cr();
1332
1333 if (ShenandoahPacing) {
1334 pacer()->print_on(&ls);
1335 }
1336
1337 ls.cr();
1338 ls.cr();
1339
1340 if (ShenandoahAllocationTrace) {
1341 assert(alloc_tracker() != NULL, "Must be");
1342 alloc_tracker()->print_on(&ls);
1343 } else {
1344 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1345 }
1346 }
1347 }
1348
1349 void ShenandoahHeap::verify(VerifyOption vo) {
1350 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1351 if (ShenandoahVerify) {
1352 verifier()->verify_generic(vo);
1353 } else {
1354 // TODO: Consider allocating verification bitmaps on demand,
1355 // and turn this on unconditionally.
1356 }
1357 }
1358 }
1359 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1360 return _free_set->capacity();
1361 }
1362
1363 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1364 private:
1365 MarkBitMap* _bitmap;
1366 Stack<oop,mtGC>* _oop_stack;
1367
1368 template <class T>
1369 void do_oop_work(T* p) {
1370 T o = oopDesc::load_heap_oop(p);
1371 if (!oopDesc::is_null(o)) {
1372 oop obj = oopDesc::decode_heap_oop_not_null(o);
1373 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1374 assert(oopDesc::is_oop(obj), "must be a valid oop");
1375 if (!_bitmap->isMarked((HeapWord*) obj)) {
1376 _bitmap->mark((HeapWord*) obj);
1377 _oop_stack->push(obj);
1378 }
1379 }
1380 }
1381 public:
1382 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1383 _bitmap(bitmap), _oop_stack(oop_stack) {}
1384 void do_oop(oop* p) { do_oop_work(p); }
1385 void do_oop(narrowOop* p) { do_oop_work(p); }
1386 };
1387
1388 /*
1389 * This is public API, used in preparation of object_iterate().
1390 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1391 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1392 * control, we call SH::make_tlabs_parsable().
1393 */
1394 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1395 // No-op.
1396 }
1397
1398 /*
1399 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1400 *
1401 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1402 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1403 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1404 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1405 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1406 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1407 * wiped the bitmap in preparation for next marking).
1408 *
1409 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1410 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1411 * is allowed to report dead objects, but is not required to do so.
1412 */
1413 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1414 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1415 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1416 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1417 return;
1418 }
1419
1420 Stack<oop,mtGC> oop_stack;
1421
1422 // First, we process all GC roots. This populates the work stack with initial objects.
1423 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1424 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1425 CLDToOopClosure clds(&oops, false);
1426 CodeBlobToOopClosure blobs(&oops, false);
1427 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1428
1429 // Work through the oop stack to traverse heap.
1430 while (! oop_stack.is_empty()) {
1431 oop obj = oop_stack.pop();
1432 assert(oopDesc::is_oop(obj), "must be a valid oop");
1433 cl->do_object(obj);
1434 obj->oop_iterate(&oops);
1435 }
1436
1437 assert(oop_stack.is_empty(), "should be empty");
1438
1439 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1440 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1441 }
1442 }
1443
1444 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1445 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1446 object_iterate(cl);
1447 }
1448
1449 // Apply blk->heap_region_do() on all committed regions in address order,
1450 // terminating the iteration early if heap_region_do() returns true.
1451 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1452 for (size_t i = 0; i < num_regions(); i++) {
1453 ShenandoahHeapRegion* current = get_region(i);
1454 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1455 continue;
1456 }
1457 if (skip_cset_regions && in_collection_set(current)) {
1458 continue;
1459 }
1460 if (blk->heap_region_do(current)) {
1461 return;
1462 }
1463 }
1464 }
1465
1466 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1467 private:
1468 ShenandoahHeap* sh;
1469 public:
1470 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1471
1472 bool heap_region_do(ShenandoahHeapRegion* r) {
1473 r->clear_live_data();
1474 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1475 return false;
1476 }
1477 };
1478
1479 void ShenandoahHeap::op_init_mark() {
1480 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1481
1482 assert(is_next_bitmap_clear(), "need clear marking bitmap");
1483
1484 if (ShenandoahVerify) {
1485 verifier()->verify_before_concmark();
1486 }
1487
1488 {
1489 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1490 accumulate_statistics_all_tlabs();
1491 }
1492
1493 set_concurrent_mark_in_progress(true);
1494 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1495 if (UseTLAB) {
1496 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1497 make_tlabs_parsable(true);
1498 }
1499
1500 {
1501 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1502 ShenandoahClearLivenessClosure clc(this);
1503 heap_region_iterate(&clc);
1504 }
1505
1506 // Make above changes visible to worker threads
1507 OrderAccess::fence();
1508
1509 concurrentMark()->init_mark_roots();
1510
1511 if (UseTLAB) {
1512 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1513 resize_all_tlabs();
1514 }
1515
1516 if (ShenandoahPacing) {
1517 pacer()->setup_for_mark();
1518 }
1519 }
1520
1521 void ShenandoahHeap::op_mark() {
1522 concurrentMark()->mark_from_roots();
1523
1524 // Allocations happen during concurrent mark, record peak after the phase:
1525 shenandoahPolicy()->record_peak_occupancy();
1526 }
1527
1528 void ShenandoahHeap::op_final_mark() {
1529 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1530
1531 // It is critical that we
1532 // evacuate roots right after finishing marking, so that we don't
1533 // get unmarked objects in the roots.
1534
1535 if (! cancelled_concgc()) {
1536 concurrentMark()->finish_mark_from_roots();
1537 stop_concurrent_marking();
1538
1539 {
1540 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1541 prepare_for_concurrent_evacuation();
1542 }
1543
1544 // If collection set has candidates, start evacuation.
1545 // Otherwise, bypass the rest of the cycle.
1546 if (!collection_set()->is_empty()) {
1547 set_evacuation_in_progress(true);
1548 // From here on, we need to update references.
1549 set_has_forwarded_objects(true);
1550
1551 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1552 evacuate_and_update_roots();
1553 }
1554
1555 if (ShenandoahPacing) {
1556 pacer()->setup_for_evac();
1557 }
1558 } else {
1559 concurrentMark()->cancel();
1560 stop_concurrent_marking();
1561
1562 if (process_references()) {
1563 // Abandon reference processing right away: pre-cleaning must have failed.
1564 ReferenceProcessor *rp = ref_processor();
1565 rp->disable_discovery();
1566 rp->abandon_partial_discovery();
1567 rp->verify_no_references_recorded();
1568 }
1569 }
1570 }
1571
1572 void ShenandoahHeap::op_final_evac() {
1573 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1574
1575 set_evacuation_in_progress(false);
1576 if (ShenandoahVerify) {
1577 verifier()->verify_after_evacuation();
1578 }
1579 }
1580
1581 void ShenandoahHeap::op_evac() {
1582
1583 LogTarget(Trace, gc, region) lt_region;
1584 LogTarget(Trace, gc, cset) lt_cset;
1585
1586 if (lt_region.is_enabled()) {
1587 ResourceMark rm;
1588 LogStream ls(lt_region);
1589 ls.print_cr("All available regions:");
1590 print_heap_regions_on(&ls);
1591 }
1592
1593 if (lt_cset.is_enabled()) {
1594 ResourceMark rm;
1595 LogStream ls(lt_cset);
1596 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1597 _collection_set->print_on(&ls);
1598
1599 ls.print_cr("Free set:");
1600 _free_set->print_on(&ls);
1601 }
1602
1603 ShenandoahParallelEvacuationTask task(this, _collection_set);
1604 workers()->run_task(&task);
1605
1606 if (lt_cset.is_enabled()) {
1607 ResourceMark rm;
1608 LogStream ls(lt_cset);
1609 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1610 _collection_set->count());
1611 _collection_set->print_on(&ls);
1612
1613 ls.print_cr("After evacuation free set:");
1614 _free_set->print_on(&ls);
1615 }
1616
1617 if (lt_region.is_enabled()) {
1618 ResourceMark rm;
1619 LogStream ls(lt_region);
1620 ls.print_cr("All regions after evacuation:");
1621 print_heap_regions_on(&ls);
1622 }
1623
1624 // Allocations happen during evacuation, record peak after the phase:
1625 shenandoahPolicy()->record_peak_occupancy();
1626 }
1627
1628 void ShenandoahHeap::op_updaterefs() {
1629 update_heap_references(true);
1630
1631 // Allocations happen during update-refs, record peak after the phase:
1632 shenandoahPolicy()->record_peak_occupancy();
1633 }
1634
1635 void ShenandoahHeap::op_cleanup() {
1636 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1637 free_set()->recycle_trash();
1638
1639 // Allocations happen during cleanup, record peak after the phase:
1640 shenandoahPolicy()->record_peak_occupancy();
1641 }
1642
1643 void ShenandoahHeap::op_cleanup_bitmaps() {
1644 op_cleanup();
1645
1646 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1647 reset_next_mark_bitmap();
1648
1649 // Allocations happen during bitmap cleanup, record peak after the phase:
1650 shenandoahPolicy()->record_peak_occupancy();
1651 }
1652
1653 void ShenandoahHeap::op_cleanup_traversal() {
1654
1655 {
1656 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1657 reset_next_mark_bitmap_traversal();
1658 }
1659
1660 op_cleanup();
1661
1662 // Allocations happen during bitmap cleanup, record peak after the phase:
1663 shenandoahPolicy()->record_peak_occupancy();
1664 }
1665
1666 void ShenandoahHeap::op_preclean() {
1667 concurrentMark()->preclean_weak_refs();
1668
1669 // Allocations happen during concurrent preclean, record peak after the phase:
1670 shenandoahPolicy()->record_peak_occupancy();
1671 }
1672
1673 void ShenandoahHeap::op_init_traversal() {
1674 traversal_gc()->init_traversal_collection();
1675 }
1676
1677 void ShenandoahHeap::op_traversal() {
1678 traversal_gc()->concurrent_traversal_collection();
1679 }
1680
1681 void ShenandoahHeap::op_final_traversal() {
1682 traversal_gc()->final_traversal_collection();
1683 }
1684
1685 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1686 full_gc()->do_it(cause);
1687 }
1688
1689 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1690 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1691 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1692 // some phase, we have to upgrade the Degenerate GC to Full GC.
1693
1694 clear_cancelled_concgc();
1695
1696 size_t used_before = used();
1697
1698 switch (point) {
1699 case _degenerated_evac:
1700 // Not possible to degenerate from here, upgrade to Full GC right away.
1701 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1702 op_degenerated_fail();
1703 return;
1704
1705 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1706 // but enters it at different points, depending on which concurrent phase had
1707 // degenerated.
1708
1709 case _degenerated_traversal:
1710 {
1711 ShenandoahHeapLocker locker(lock());
1712 collection_set()->clear_current_index();
1713 for (size_t i = 0; i < collection_set()->count(); i++) {
1714 ShenandoahHeapRegion* r = collection_set()->next();
1715 r->make_regular_bypass();
1716 }
1717 collection_set()->clear();
1718 }
1719 op_final_traversal();
1720 op_cleanup_traversal();
1721 return;
1722
1723 case _degenerated_outside_cycle:
1724 if (shenandoahPolicy()->can_do_traversal_gc()) {
1725 // Not possible to degenerate from here, upgrade to Full GC right away.
1726 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1727 op_degenerated_fail();
1728 return;
1729 }
1730 op_init_mark();
1731 if (cancelled_concgc()) {
1732 op_degenerated_fail();
1733 return;
1734 }
1735
1736 case _degenerated_mark:
1737 op_final_mark();
1738 if (cancelled_concgc()) {
1739 op_degenerated_fail();
1740 return;
1741 }
1742
1743 op_cleanup();
1744
1745 // If heuristics thinks we should do the cycle, this flag would be set,
1746 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1747 if (is_evacuation_in_progress()) {
1748 op_evac();
1749 if (cancelled_concgc()) {
1750 op_degenerated_fail();
1751 return;
1752 }
1753 }
1754
1755 // If heuristics thinks we should do the cycle, this flag would be set,
1756 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1757 if (has_forwarded_objects()) {
1758 op_init_updaterefs();
1759 if (cancelled_concgc()) {
1760 op_degenerated_fail();
1761 return;
1762 }
1763 }
1764
1765 case _degenerated_updaterefs:
1766 if (has_forwarded_objects()) {
1767 op_final_updaterefs();
1768 if (cancelled_concgc()) {
1769 op_degenerated_fail();
1770 return;
1771 }
1772 }
1773
1774 op_cleanup_bitmaps();
1775 break;
1776
1777 default:
1778 ShouldNotReachHere();
1779 }
1780
1781 if (ShenandoahVerify) {
1782 verifier()->verify_after_degenerated();
1783 }
1784
1785 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1786 // because that probably means the heap is overloaded and/or fragmented.
1787 size_t used_after = used();
1788 size_t difference = (used_before > used_after) ? used_before - used_after : 0;
1789 if (difference < ShenandoahHeapRegion::region_size_words()) {
1790 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1791 op_degenerated_futile();
1792 }
1793 }
1794
1795 void ShenandoahHeap::op_degenerated_fail() {
1796 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1797 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1798 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1799 }
1800
1801 void ShenandoahHeap::op_degenerated_futile() {
1802 log_info(gc)("Degenerated GC had not reclaimed enough, upgrading to Full GC");
1803 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1804 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1805 }
1806
1807 void ShenandoahHeap::swap_mark_bitmaps() {
1808 // Swap bitmaps.
1809 MarkBitMap* tmp1 = _complete_mark_bit_map;
1810 _complete_mark_bit_map = _next_mark_bit_map;
1811 _next_mark_bit_map = tmp1;
1812
1813 // Swap top-at-mark-start pointers
1814 HeapWord** tmp2 = _complete_top_at_mark_starts;
1815 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1816 _next_top_at_mark_starts = tmp2;
1817
1818 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1819 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1820 _next_top_at_mark_starts_base = tmp3;
1821 }
1822
1823
1824 void ShenandoahHeap::stop_concurrent_marking() {
1825 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1826 if (! cancelled_concgc()) {
1827 // If we needed to update refs, and concurrent marking has been cancelled,
1828 // we need to finish updating references.
1829 set_has_forwarded_objects(false);
1830 swap_mark_bitmaps();
1831 }
1832 set_concurrent_mark_in_progress(false);
1833
1834 LogTarget(Trace, gc, region) lt;
1835 if (lt.is_enabled()) {
1836 ResourceMark rm;
1837 LogStream ls(lt);
1838 ls.print_cr("Regions at stopping the concurrent mark:");
1839 print_heap_regions_on(&ls);
1840 }
1841 }
1842
1843 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1844 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1845 _gc_state.set_cond(mask, value);
1846 JavaThread::set_gc_state_all_threads(_gc_state.raw_value());
1847 }
1848
1849 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1850 set_gc_state_mask(MARKING, in_progress);
1851 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1852 }
1853
1854 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1855 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1856 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1857 }
1858
1859 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1860 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1861 set_gc_state_mask(EVACUATION, in_progress);
1862 }
1863
1864 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1865 // Initialize Brooks pointer for the next object
1866 HeapWord* result = obj + BrooksPointer::word_size();
1867 BrooksPointer::initialize(oop(result));
1868 return result;
1869 }
1870
1871 uint ShenandoahHeap::oop_extra_words() {
1872 return BrooksPointer::word_size();
1873 }
1874
1875 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1876 _heap(ShenandoahHeap::heap_no_check()) {
1877 }
1878
1879 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1880 _heap(ShenandoahHeap::heap_no_check()) {
1881 }
1882
1883 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1884 if (oopDesc::is_null(obj)) {
1885 return false;
1886 }
1887 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1888 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_mark_in_progress() || _heap->is_concurrent_traversal_in_progress())
1889 return _heap->is_marked_next(obj);
1890 }
1891
1892 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1893 if (oopDesc::is_null(obj)) {
1894 return false;
1895 }
1896 shenandoah_assert_not_forwarded(NULL, obj);
1897 return _heap->is_marked_next(obj);
1898 }
1899
1900 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1901 return has_forwarded_objects() ?
1902 (BoolObjectClosure*) &_forwarded_is_alive :
1903 (BoolObjectClosure*) &_is_alive;
1904 }
1905
1906 void ShenandoahHeap::ref_processing_init() {
1907 MemRegion mr = reserved_region();
1908
1909 _forwarded_is_alive.init(this);
1910 _is_alive.init(this);
1911 assert(_max_workers > 0, "Sanity");
1912
1913 _ref_processor =
1914 new ReferenceProcessor(mr, // span
1915 ParallelRefProcEnabled, // MT processing
1916 _max_workers, // Degree of MT processing
1917 true, // MT discovery
1918 _max_workers, // Degree of MT discovery
1919 false, // Reference discovery is not atomic
1920 NULL); // No closure, should be installed before use
1921
1922 shenandoah_assert_rp_isalive_not_installed();
1923 }
1924
1925
1926 GCTracer* ShenandoahHeap::tracer() {
1927 return shenandoahPolicy()->tracer();
1928 }
1929
1930 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1931 return _free_set->used();
1932 }
1933
1934 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1935 if (try_cancel_concgc()) {
1936 FormatBuffer<> msg("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1937 log_info(gc)("%s", msg.buffer());
1938 Events::log(Thread::current(), "%s", msg.buffer());
1939 }
1940 }
1941
1942 uint ShenandoahHeap::max_workers() {
1943 return _max_workers;
1944 }
1945
1946 void ShenandoahHeap::stop() {
1947 // The shutdown sequence should be able to terminate when GC is running.
1948
1949 // Step 0. Notify policy to disable event recording.
1950 _shenandoah_policy->record_shutdown();
1951
1952 // Step 1. Notify control thread that we are in shutdown.
1953 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1954 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1955 _control_thread->prepare_for_graceful_shutdown();
1956
1957 // Step 2. Notify GC workers that we are cancelling GC.
1958 cancel_concgc(GCCause::_shenandoah_stop_vm);
1959
1960 // Step 3. Wait until GC worker exits normally.
1961 _control_thread->stop();
1962
1963 // Step 4. Stop String Dedup thread if it is active
1964 if (ShenandoahStringDedup::is_enabled()) {
1965 ShenandoahStringDedup::stop();
1966 }
1967 }
1968
1969 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1970 ShenandoahPhaseTimings::Phase phase_root =
1971 full_gc ?
1972 ShenandoahPhaseTimings::full_gc_purge :
1973 ShenandoahPhaseTimings::purge;
1974
1975 ShenandoahPhaseTimings::Phase phase_unload =
1976 full_gc ?
1977 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1978 ShenandoahPhaseTimings::purge_class_unload;
1979
1980 ShenandoahPhaseTimings::Phase phase_cldg =
1981 full_gc ?
1982 ShenandoahPhaseTimings::full_gc_purge_cldg :
1983 ShenandoahPhaseTimings::purge_cldg;
1984
1985 ShenandoahPhaseTimings::Phase phase_par =
1986 full_gc ?
1987 ShenandoahPhaseTimings::full_gc_purge_par :
1988 ShenandoahPhaseTimings::purge_par;
1989
1990 ShenandoahPhaseTimings::Phase phase_par_classes =
1991 full_gc ?
1992 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1993 ShenandoahPhaseTimings::purge_par_classes;
1994
1995 ShenandoahPhaseTimings::Phase phase_par_codecache =
1996 full_gc ?
1997 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1998 ShenandoahPhaseTimings::purge_par_codecache;
1999
2000 ShenandoahPhaseTimings::Phase phase_par_rmt =
2001 full_gc ?
2002 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
2003 ShenandoahPhaseTimings::purge_par_rmt;
2004
2005 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2006 full_gc ?
2007 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2008 ShenandoahPhaseTimings::purge_par_symbstring;
2009
2010 ShenandoahPhaseTimings::Phase phase_par_sync =
2011 full_gc ?
2012 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2013 ShenandoahPhaseTimings::purge_par_sync;
2014
2015 ShenandoahGCPhase root_phase(phase_root);
2016
2017 BoolObjectClosure* is_alive = is_alive_closure();
2018
2019 bool purged_class;
2020
2021 // Unload classes and purge SystemDictionary.
2022 {
2023 ShenandoahGCPhase phase(phase_unload);
2024 purged_class = SystemDictionary::do_unloading(is_alive,
2025 gc_timer(),
2026 false /* defer cleaning */);
2027 }
2028
2029 {
2030 ShenandoahGCPhase phase(phase_par);
2031 uint active = _workers->active_workers();
2032 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
2033 _workers->run_task(&unlink_task);
2034
2035 ShenandoahPhaseTimings* p = phase_timings();
2036 ParallelCleaningTimes times = unlink_task.times();
2037
2038 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2039 // by active workers to get average time per worker, that would add up to wall time.
2040 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2041 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2042 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
2043 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2044 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2045 }
2046
2047 if (ShenandoahStringDedup::is_enabled()) {
2048 ShenandoahPhaseTimings::Phase phase_par_string_dedup =
2049 full_gc ?
2050 ShenandoahPhaseTimings::full_gc_purge_par_string_dedup :
2051 ShenandoahPhaseTimings::purge_par_string_dedup;
2052 ShenandoahGCPhase phase(phase_par_string_dedup);
2053 ShenandoahStringDedup::parallel_cleanup();
2054 }
2055
2056
2057 {
2058 ShenandoahGCPhase phase(phase_cldg);
2059 ClassLoaderDataGraph::purge();
2060 }
2061 }
2062
2063 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2064 set_gc_state_mask(HAS_FORWARDED, cond);
2065 }
2066
2067 void ShenandoahHeap::set_process_references(bool pr) {
2068 _process_references.set_cond(pr);
2069 }
2070
2071 void ShenandoahHeap::set_unload_classes(bool uc) {
2072 _unload_classes.set_cond(uc);
2073 }
2074
2075 bool ShenandoahHeap::process_references() const {
2076 return _process_references.is_set();
2077 }
2078
2079 bool ShenandoahHeap::unload_classes() const {
2080 return _unload_classes.is_set();
2081 }
2082
2083 //fixme this should be in heapregionset
2084 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2085 size_t region_idx = r->region_number() + 1;
2086 ShenandoahHeapRegion* next = get_region(region_idx);
2087 guarantee(next->region_number() == region_idx, "region number must match");
2088 while (next->is_humongous()) {
2089 region_idx = next->region_number() + 1;
2090 next = get_region(region_idx);
2091 guarantee(next->region_number() == region_idx, "region number must match");
2092 }
2093 return next;
2094 }
2095
2096 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2097 return _monitoring_support;
2098 }
2099
2100 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
2101 return _complete_mark_bit_map;
2102 }
2103
2104 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
2105 return _next_mark_bit_map;
2106 }
2107
2108 address ShenandoahHeap::in_cset_fast_test_addr() {
2109 ShenandoahHeap* heap = ShenandoahHeap::heap();
2110 assert(heap->collection_set() != NULL, "Sanity");
2111 return (address) heap->collection_set()->biased_map_address();
2112 }
2113
2114 address ShenandoahHeap::cancelled_concgc_addr() {
2115 return (address) ShenandoahHeap::heap()->_cancelled_concgc.addr_of();
2116 }
2117
2118 address ShenandoahHeap::gc_state_addr() {
2119 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2120 }
2121
2122 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2123 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2124 }
2125
2126 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2127 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2128 }
2129
2130 ShenandoahPacer* ShenandoahHeap::pacer() const {
2131 assert (_pacer != NULL, "sanity");
2132 return _pacer;
2133 }
2134
2135 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2136 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2137 _next_top_at_mark_starts[index] = addr;
2138 }
2139
2140 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2141 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2142 return _next_top_at_mark_starts[index];
2143 }
2144
2145 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2146 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2147 _complete_top_at_mark_starts[index] = addr;
2148 }
2149
2150 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2151 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2152 return _complete_top_at_mark_starts[index];
2153 }
2154
2155 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2156 _degenerated_gc_in_progress.set_cond(in_progress);
2157 }
2158
2159 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2160 _full_gc_in_progress.set_cond(in_progress);
2161 }
2162
2163 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2164 assert (is_full_gc_in_progress(), "should be");
2165 _full_gc_move_in_progress.set_cond(in_progress);
2166 }
2167
2168 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2169 set_gc_state_mask(UPDATEREFS, in_progress);
2170 }
2171
2172 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2173 ShenandoahCodeRoots::add_nmethod(nm);
2174 }
2175
2176 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2177 ShenandoahCodeRoots::remove_nmethod(nm);
2178 }
2179
2180 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2181 o = BarrierSet::barrier_set()->write_barrier(o);
2182 ShenandoahHeapLocker locker(lock());
2183 heap_region_containing(o)->make_pinned();
2184 return o;
2185 }
2186
2187 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2188 o = BarrierSet::barrier_set()->read_barrier(o);
2189 ShenandoahHeapLocker locker(lock());
2190 heap_region_containing(o)->make_unpinned();
2191 }
2192
2193 GCTimer* ShenandoahHeap::gc_timer() const {
2194 return _gc_timer;
2195 }
2196
2197 #ifdef ASSERT
2198 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2199 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2200
2201 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2202 if (UseDynamicNumberOfGCThreads ||
2203 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2204 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2205 } else {
2206 // Use ParallelGCThreads inside safepoints
2207 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2208 }
2209 } else {
2210 if (UseDynamicNumberOfGCThreads ||
2211 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2212 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2213 } else {
2214 // Use ConcGCThreads outside safepoints
2215 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2216 }
2217 }
2218 }
2219 #endif
2220
2221 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
2222 return _connection_matrix;
2223 }
2224
2225 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2226 return _traversal_gc;
2227 }
2228
2229 ShenandoahVerifier* ShenandoahHeap::verifier() {
2230 guarantee(ShenandoahVerify, "Should be enabled");
2231 assert (_verifier != NULL, "sanity");
2232 return _verifier;
2233 }
2234
2235 template<class T>
2236 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2237 private:
2238 T cl;
2239 ShenandoahHeap* _heap;
2240 ShenandoahRegionIterator* _regions;
2241 bool _concurrent;
2242 public:
2243 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2244 AbstractGangTask("Concurrent Update References Task"),
2245 cl(T()),
2246 _heap(ShenandoahHeap::heap()),
2247 _regions(regions),
2248 _concurrent(concurrent) {
2249 }
2250
2251 void work(uint worker_id) {
2252 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2253 ShenandoahHeapRegion* r = _regions->next();
2254 while (r != NULL) {
2255 if (_heap->in_collection_set(r)) {
2256 HeapWord* bottom = r->bottom();
2257 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2258 if (top > bottom) {
2259 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2260 }
2261 } else {
2262 if (r->is_active()) {
2263 _heap->marked_object_oop_safe_iterate(r, &cl);
2264 if (ShenandoahPacing) {
2265 _heap->pacer()->report_updaterefs(r->get_live_data_words());
2266 }
2267 }
2268 }
2269 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
2270 return;
2271 }
2272 r = _regions->next();
2273 }
2274 }
2275 };
2276
2277 void ShenandoahHeap::update_heap_references(bool concurrent) {
2278 if (UseShenandoahMatrix) {
2279 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(&_update_refs_iterator, concurrent);
2280 workers()->run_task(&task);
2281 } else {
2282 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2283 workers()->run_task(&task);
2284 }
2285 }
2286
2287 void ShenandoahHeap::op_init_updaterefs() {
2288 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2289
2290 if (ShenandoahVerify) {
2291 verifier()->verify_before_updaterefs();
2292 }
2293
2294 set_evacuation_in_progress(false);
2295 set_update_refs_in_progress(true);
2296 make_tlabs_parsable(true);
2297 if (UseShenandoahMatrix) {
2298 connection_matrix()->clear_all();
2299 }
2300 for (uint i = 0; i < num_regions(); i++) {
2301 ShenandoahHeapRegion* r = get_region(i);
2302 r->set_concurrent_iteration_safe_limit(r->top());
2303 }
2304
2305 // Reset iterator.
2306 _update_refs_iterator = ShenandoahRegionIterator();
2307
2308 if (ShenandoahPacing) {
2309 pacer()->setup_for_updaterefs();
2310 }
2311 }
2312
2313 void ShenandoahHeap::op_final_updaterefs() {
2314 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2315
2316 // Check if there is left-over work, and finish it
2317 if (_update_refs_iterator.has_next()) {
2318 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2319
2320 // Finish updating references where we left off.
2321 clear_cancelled_concgc();
2322 update_heap_references(false);
2323 }
2324
2325 // Clear cancelled conc GC, if set. On cancellation path, the block before would handle
2326 // everything. On degenerated paths, cancelled gc would not be set anyway.
2327 if (cancelled_concgc()) {
2328 clear_cancelled_concgc();
2329 }
2330 assert(!cancelled_concgc(), "Should have been done right before");
2331
2332 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2333
2334 // Allocations might have happened before we STWed here, record peak:
2335 shenandoahPolicy()->record_peak_occupancy();
2336
2337 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2338
2339 trash_cset_regions();
2340 set_has_forwarded_objects(false);
2341
2342 if (ShenandoahVerify) {
2343 verifier()->verify_after_updaterefs();
2344 }
2345
2346 {
2347 ShenandoahHeapLocker locker(lock());
2348 _free_set->rebuild();
2349 }
2350
2351 set_update_refs_in_progress(false);
2352 }
2353
2354 void ShenandoahHeap::set_alloc_seq_gc_start() {
2355 // Take next number, the start seq number is inclusive
2356 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2357 }
2358
2359 void ShenandoahHeap::set_alloc_seq_gc_end() {
2360 // Take current number, the end seq number is also inclusive
2361 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2362 }
2363
2364
2365 #ifdef ASSERT
2366 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2367 _lock.assert_owned_by_current_thread();
2368 }
2369
2370 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2371 _lock.assert_not_owned_by_current_thread();
2372 }
2373
2374 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2375 _lock.assert_owned_by_current_thread_or_safepoint();
2376 }
2377 #endif
2378
2379 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2380 print_on(st);
2381 print_heap_regions_on(st);
2382 }
2383
2384 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2385 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2386
2387 size_t regions_from = _bitmap_regions_per_slice * slice;
2388 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2389 for (size_t g = regions_from; g < regions_to; g++) {
2390 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2391 if (skip_self && g == r->region_number()) continue;
2392 if (get_region(g)->is_committed()) {
2393 return true;
2394 }
2395 }
2396 return false;
2397 }
2398
2399 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2400 assert_heaplock_owned_by_current_thread();
2401
2402 if (is_bitmap_slice_committed(r, true)) {
2403 // Some other region from the group is already committed, meaning the bitmap
2404 // slice is already committed, we exit right away.
2405 return true;
2406 }
2407
2408 // Commit the bitmap slice:
2409 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2410 size_t off = _bitmap_bytes_per_slice * slice;
2411 size_t len = _bitmap_bytes_per_slice;
2412 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2413 return false;
2414 }
2415 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2416 return false;
2417 }
2418 return true;
2419 }
2420
2421 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2422 assert_heaplock_owned_by_current_thread();
2423
2424 if (is_bitmap_slice_committed(r, true)) {
2425 // Some other region from the group is still committed, meaning the bitmap
2426 // slice is should stay committed, exit right away.
2427 return true;
2428 }
2429
2430 // Uncommit the bitmap slice:
2431 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2432 size_t off = _bitmap_bytes_per_slice * slice;
2433 size_t len = _bitmap_bytes_per_slice;
2434 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2435 return false;
2436 }
2437 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2438 return false;
2439 }
2440 return true;
2441 }
2442
2443 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2444 assert_heaplock_owned_by_current_thread();
2445 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2446
2447 if (is_bitmap_slice_committed(r, true)) {
2448 // Some other region from the group is still committed, meaning the bitmap
2449 // slice is should stay committed, exit right away.
2450 return true;
2451 }
2452
2453 // Idle the bitmap slice:
2454 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2455 size_t off = _bitmap_bytes_per_slice * slice;
2456 size_t len = _bitmap_bytes_per_slice;
2457 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2458 return false;
2459 }
2460 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2461 return false;
2462 }
2463 return true;
2464 }
2465
2466 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2467 assert_heaplock_owned_by_current_thread();
2468 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2469 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2470 size_t off = _bitmap_bytes_per_slice * slice;
2471 size_t len = _bitmap_bytes_per_slice;
2472 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2473 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2474 }
2475
2476 void ShenandoahHeap::safepoint_synchronize_begin() {
2477 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2478 SuspendibleThreadSet::synchronize();
2479 }
2480 }
2481
2482 void ShenandoahHeap::safepoint_synchronize_end() {
2483 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2484 SuspendibleThreadSet::desynchronize();
2485 }
2486 }
2487
2488 void ShenandoahHeap::vmop_entry_init_mark() {
2489 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2490 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2491 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2492
2493 try_inject_alloc_failure();
2494 VM_ShenandoahInitMark op;
2495 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2496 }
2497
2498 void ShenandoahHeap::vmop_entry_final_mark() {
2499 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2500 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2501 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2502
2503 try_inject_alloc_failure();
2504 VM_ShenandoahFinalMarkStartEvac op;
2505 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2506 }
2507
2508 void ShenandoahHeap::vmop_entry_final_evac() {
2509 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2510 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2511 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2512
2513 VM_ShenandoahFinalEvac op;
2514 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2515 }
2516
2517 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2518 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2519 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2520 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2521
2522 try_inject_alloc_failure();
2523 VM_ShenandoahInitUpdateRefs op;
2524 VMThread::execute(&op);
2525 }
2526
2527 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2528 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2529 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2530 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2531
2532 try_inject_alloc_failure();
2533 VM_ShenandoahFinalUpdateRefs op;
2534 VMThread::execute(&op);
2535 }
2536
2537 void ShenandoahHeap::vmop_entry_init_traversal() {
2538 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2539 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2540 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2541
2542 try_inject_alloc_failure();
2543 VM_ShenandoahInitTraversalGC op;
2544 VMThread::execute(&op);
2545 }
2546
2547 void ShenandoahHeap::vmop_entry_final_traversal() {
2548 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2549 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2550 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2551
2552 try_inject_alloc_failure();
2553 VM_ShenandoahFinalTraversalGC op;
2554 VMThread::execute(&op);
2555 }
2556
2557 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2558 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2559 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2560 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2561
2562 try_inject_alloc_failure();
2563 VM_ShenandoahFullGC op(cause);
2564 VMThread::execute(&op);
2565 }
2566
2567 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2568 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2569 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2570 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2571
2572 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2573 VMThread::execute(°enerated_gc);
2574 }
2575
2576 void ShenandoahHeap::entry_init_mark() {
2577 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2578 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2579
2580 FormatBuffer<> msg("Pause Init Mark%s%s%s",
2581 has_forwarded_objects() ? " (update refs)" : "",
2582 process_references() ? " (process refs)" : "",
2583 unload_classes() ? " (unload classes)" : "");
2584 GCTraceTime(Info, gc) time(msg, gc_timer());
2585 EventMark em("%s", msg.buffer());
2586
2587 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_init_marking());
2588
2589 op_init_mark();
2590 }
2591
2592 void ShenandoahHeap::entry_final_mark() {
2593 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2594 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2595
2596 FormatBuffer<> msg("Pause Final Mark%s%s%s",
2597 has_forwarded_objects() ? " (update refs)" : "",
2598 process_references() ? " (process refs)" : "",
2599 unload_classes() ? " (unload classes)" : "");
2600 GCTraceTime(Info, gc) time(msg, gc_timer());
2601 EventMark em("%s", msg.buffer());
2602
2603 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_marking());
2604
2605 op_final_mark();
2606 }
2607
2608 void ShenandoahHeap::entry_final_evac() {
2609 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2610 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2611
2612 FormatBuffer<> msg("Pause Final Evac");
2613 GCTraceTime(Info, gc) time(msg, gc_timer());
2614 EventMark em("%s", msg.buffer());
2615
2616 op_final_evac();
2617 }
2618
2619 void ShenandoahHeap::entry_init_updaterefs() {
2620 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2621 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2622
2623 static const char* msg = "Pause Init Update Refs";
2624 GCTraceTime(Info, gc) time(msg, gc_timer());
2625 EventMark em("%s", msg);
2626
2627 // No workers used in this phase, no setup required
2628
2629 op_init_updaterefs();
2630 }
2631
2632 void ShenandoahHeap::entry_final_updaterefs() {
2633 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2634 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2635
2636 static const char* msg = "Pause Final Update Refs";
2637 GCTraceTime(Info, gc) time(msg, gc_timer());
2638 EventMark em("%s", msg);
2639
2640 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_update_ref());
2641
2642 op_final_updaterefs();
2643 }
2644
2645 void ShenandoahHeap::entry_init_traversal() {
2646 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2647 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2648
2649 static const char* msg = "Pause Init Traversal";
2650 GCTraceTime(Info, gc) time(msg, gc_timer());
2651 EventMark em("%s", msg);
2652
2653 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2654
2655 op_init_traversal();
2656 }
2657
2658 void ShenandoahHeap::entry_final_traversal() {
2659 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2660 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2661
2662 static const char* msg = "Pause Final Traversal";
2663 GCTraceTime(Info, gc) time(msg, gc_timer());
2664 EventMark em("%s", msg);
2665
2666 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2667
2668 op_final_traversal();
2669 }
2670
2671 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2672 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2673 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2674
2675 static const char* msg = "Pause Full";
2676 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2677 EventMark em("%s", msg);
2678
2679 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_fullgc());
2680
2681 op_full(cause);
2682 }
2683
2684 void ShenandoahHeap::entry_degenerated(int point) {
2685 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2686 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2687
2688 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2689 FormatBuffer<> msg("Pause Degenerated GC (%s)", degen_point_to_string(dpoint));
2690 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2691 EventMark em("%s", msg.buffer());
2692
2693 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated());
2694
2695 set_degenerated_gc_in_progress(true);
2696 op_degenerated(dpoint);
2697 set_degenerated_gc_in_progress(false);
2698 }
2699
2700 void ShenandoahHeap::entry_mark() {
2701 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2702
2703 FormatBuffer<> msg("Concurrent marking%s%s%s",
2704 has_forwarded_objects() ? " (update refs)" : "",
2705 process_references() ? " (process refs)" : "",
2706 unload_classes() ? " (unload classes)" : "");
2707 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2708 EventMark em("%s", msg.buffer());
2709
2710 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_marking());
2711
2712 try_inject_alloc_failure();
2713 op_mark();
2714 }
2715
2716 void ShenandoahHeap::entry_evac() {
2717 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2718 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2719
2720 static const char* msg = "Concurrent evacuation";
2721 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2722 EventMark em("%s", msg);
2723
2724 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_evac());
2725
2726 try_inject_alloc_failure();
2727 op_evac();
2728 }
2729
2730 void ShenandoahHeap::entry_updaterefs() {
2731 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2732
2733 static const char* msg = "Concurrent update references";
2734 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2735 EventMark em("%s", msg);
2736
2737 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref());
2738
2739 try_inject_alloc_failure();
2740 op_updaterefs();
2741 }
2742 void ShenandoahHeap::entry_cleanup() {
2743 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2744
2745 static const char* msg = "Concurrent cleanup";
2746 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2747 EventMark em("%s", msg);
2748
2749 // This phase does not use workers, no need for setup
2750
2751 try_inject_alloc_failure();
2752 op_cleanup();
2753 }
2754
2755 void ShenandoahHeap::entry_cleanup_traversal() {
2756 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2757
2758 static const char* msg = "Concurrent cleanup";
2759 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2760 EventMark em("%s", msg);
2761
2762 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2763
2764 try_inject_alloc_failure();
2765 op_cleanup_traversal();
2766 }
2767
2768 void ShenandoahHeap::entry_cleanup_bitmaps() {
2769 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2770
2771 static const char* msg = "Concurrent cleanup";
2772 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2773 EventMark em("%s", msg);
2774
2775 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup());
2776
2777 try_inject_alloc_failure();
2778 op_cleanup_bitmaps();
2779 }
2780
2781 void ShenandoahHeap::entry_preclean() {
2782 if (ShenandoahPreclean && process_references()) {
2783 static const char* msg = "Concurrent precleaning";
2784 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2785 EventMark em("%s", msg);
2786
2787 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2788
2789 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_preclean());
2790
2791 try_inject_alloc_failure();
2792 op_preclean();
2793 }
2794 }
2795
2796 void ShenandoahHeap::entry_traversal() {
2797 static const char* msg = "Concurrent traversal";
2798 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2799 EventMark em("%s", msg);
2800
2801 TraceCollectorStats tcs(is_minor_gc() ? monitoring_support()->partial_collection_counters()
2802 : monitoring_support()->concurrent_collection_counters());
2803
2804 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2805
2806 try_inject_alloc_failure();
2807 op_traversal();
2808 }
2809
2810 void ShenandoahHeap::try_inject_alloc_failure() {
2811 if (ShenandoahAllocFailureALot && !cancelled_concgc() && ((os::random() % 1000) > 950)) {
2812 _inject_alloc_failure.set();
2813 os::naked_short_sleep(1);
2814 if (cancelled_concgc()) {
2815 log_info(gc)("Allocation failure was successfully injected");
2816 }
2817 }
2818 }
2819
2820 bool ShenandoahHeap::should_inject_alloc_failure() {
2821 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2822 }
2823
2824 void ShenandoahHeap::initialize_serviceability() {
2825 _memory_pool = new ShenandoahMemoryPool(this);
2826 _cycle_memory_manager.add_pool(_memory_pool);
2827 _stw_memory_manager.add_pool(_memory_pool);
2828 }
2829
2830 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2831 GrowableArray<GCMemoryManager*> memory_managers(2);
2832 memory_managers.append(&_cycle_memory_manager);
2833 memory_managers.append(&_stw_memory_manager);
2834 return memory_managers;
2835 }
2836
2837 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2838 GrowableArray<MemoryPool*> memory_pools(1);
2839 memory_pools.append(_memory_pool);
2840 return memory_pools;
2841 }
2842
2843 void ShenandoahHeap::enter_evacuation() {
2844 _oom_evac_handler.enter_evacuation();
2845 }
2846
2847 void ShenandoahHeap::leave_evacuation() {
2848 _oom_evac_handler.leave_evacuation();
2849 }
2850
2851 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2852 _index(0),
2853 _heap(ShenandoahHeap::heap()) {}
2854
2855 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2856 _index(0),
2857 _heap(heap) {}
2858
2859 ShenandoahRegionIterator& ShenandoahRegionIterator::operator=(const ShenandoahRegionIterator& o) {
2860 _index = o._index;
2861 assert(_heap == o._heap, "must be same");
2862 return *this;
2863 }
2864
2865 bool ShenandoahRegionIterator::has_next() const {
2866 return _index < _heap->num_regions();
2867 }
2868
2869 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
2870 ShenandoahRegionIterator regions;
2871 ShenandoahHeapRegion* r = regions.next();
2872 while (r != NULL) {
2873 if (cl.heap_region_do(r)) {
2874 break;
2875 }
2876 r = regions.next();
2877 }
2878 }
2879
2880 bool ShenandoahHeap::is_minor_gc() const {
2881 return _gc_cycle_mode.get() == MINOR;
2882 }
2883
2884 bool ShenandoahHeap::is_major_gc() const {
2885 return _gc_cycle_mode.get() == MAJOR;
2886 }
2887
2888 void ShenandoahHeap::set_cycle_mode(GCCycleMode gc_cycle_mode) {
2889 _gc_cycle_mode.set(gc_cycle_mode);
2890 }
2891
2892 char ShenandoahHeap::gc_state() {
2893 return _gc_state.raw_value();
2894 }