1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/parallelCleaning.hpp"
30
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 = RawAccess<>::oop_load(p);
67 if (! CompressedOops::is_null(o)) {
68 oop obj = CompressedOops::decode_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 _bitmap0_base(bitmap0_base),
93 _bitmap1_base(bitmap1_base),
94 _bitmap_size(bitmap_size),
95 _page_size(page_size) {}
96
97 virtual void work(uint worker_id) {
98 ShenandoahHeapRegion* r = _regions.next();
99 while (r != NULL) {
100 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
101 r->region_number(), p2i(r->bottom()), p2i(r->end()));
102 os::pretouch_memory(r->bottom(), r->end(), _page_size);
103
104 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
105 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
106 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
107
108 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
109 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
110 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
111
112 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
113 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
114 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
115
116 r = _regions.next();
117 }
118 }
119 };
120
121 jint ShenandoahHeap::initialize() {
122
123 BrooksPointer::initial_checks();
124
125 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
126 size_t max_byte_size = collector_policy()->max_heap_byte_size();
127 size_t heap_alignment = collector_policy()->heap_alignment();
128
129 if (ShenandoahAlwaysPreTouch) {
130 // Enabled pre-touch means the entire heap is committed right away.
131 init_byte_size = max_byte_size;
132 }
133
134 Universe::check_alignment(max_byte_size,
135 ShenandoahHeapRegion::region_size_bytes(),
136 "shenandoah heap");
137 Universe::check_alignment(init_byte_size,
138 ShenandoahHeapRegion::region_size_bytes(),
139 "shenandoah heap");
140
141 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
142 heap_alignment);
143 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
144
145 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
146 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
147
148 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
149 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
150 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
151 _committed = _initial_size;
152
153 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
154 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
155 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
156 }
157
158 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
159 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
160
161 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
162 _free_set = new ShenandoahFreeSet(this, _num_regions);
163
164 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
165
166 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
167 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
168 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
169
170 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
171 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
172 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
173
174 if (ShenandoahPacing) {
175 _pacer = new ShenandoahPacer(this);
176 _pacer->setup_for_idle();
177 } else {
178 _pacer = NULL;
179 }
180
181 {
182 ShenandoahHeapLocker locker(lock());
183 for (size_t i = 0; i < _num_regions; i++) {
184 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
185 (HeapWord*) pgc_rs.base() + reg_size_words * i,
186 reg_size_words,
187 i,
188 i < num_committed_regions);
189
190 _complete_top_at_mark_starts_base[i] = r->bottom();
191 _next_top_at_mark_starts_base[i] = r->bottom();
192 _regions[i] = r;
193 assert(!collection_set()->is_in(i), "New region should not be in collection set");
194 }
195
196 _free_set->rebuild();
197 }
198
199 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
200 "misaligned heap: "PTR_FORMAT, p2i(base()));
201
202 // The call below uses stuff (the SATB* things) that are in G1, but probably
203 // belong into a shared location.
204 ShenandoahBarrierSet::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
205 SATB_Q_FL_lock,
206 20 /*G1SATBProcessCompletedThreshold */,
207 Shared_SATB_Q_lock);
208
209 // Reserve space for prev and next bitmap.
210 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
211 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
212 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
213 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
214
215 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
216
217 guarantee(bitmap_bytes_per_region != 0,
218 "Bitmap bytes per region should not be zero");
219 guarantee(is_power_of_2(bitmap_bytes_per_region),
220 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
221
222 if (bitmap_page_size > bitmap_bytes_per_region) {
223 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
224 _bitmap_bytes_per_slice = bitmap_page_size;
225 } else {
226 _bitmap_regions_per_slice = 1;
227 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
228 }
229
230 guarantee(_bitmap_regions_per_slice >= 1,
231 "Should have at least one region per slice: " SIZE_FORMAT,
232 _bitmap_regions_per_slice);
233
234 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
235 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
236 _bitmap_bytes_per_slice, bitmap_page_size);
237
238 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
239 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
240 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
241
242 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
243 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
244 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
245
246 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
247 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
248 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
249 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
250 "couldn't allocate initial bitmap");
251 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
252 "couldn't allocate initial bitmap");
253
254 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
255
256 if (ShenandoahVerify) {
257 ReservedSpace verify_bitmap(_bitmap_size, page_size);
258 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
259 "couldn't allocate verification bitmap");
260 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
261 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
262 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
263 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
264 }
265
266 if (ShenandoahAlwaysPreTouch) {
267 assert (!AlwaysPreTouch, "Should have been overridden");
268
269 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
270 // before initialize() below zeroes it with initializing thread. For any given region,
271 // we touch the region and the corresponding bitmaps from the same thread.
272
273 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
274 _num_regions, page_size);
275 ShenandoahPretouchTask cl(bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
276 _workers->run_task(&cl);
277 }
278
279 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
280 _complete_mark_bit_map = &_mark_bit_map0;
281
282 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
283 _next_mark_bit_map = &_mark_bit_map1;
284
285 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
286 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
287 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
288 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
289 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
290
291 if (UseShenandoahMatrix) {
292 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
293 } else {
294 _connection_matrix = NULL;
295 }
296
297 _traversal_gc = _shenandoah_policy->can_do_traversal_gc() ?
298 new ShenandoahTraversalGC(this, _num_regions) :
299 NULL;
300
301 _monitoring_support = new ShenandoahMonitoringSupport(this);
302
303 _phase_timings = new ShenandoahPhaseTimings();
304
305 if (ShenandoahAllocationTrace) {
306 _alloc_tracker = new ShenandoahAllocTracker();
307 }
308
309 ShenandoahStringDedup::initialize();
310
311 _control_thread = new ShenandoahControlThread();
312
313 ShenandoahCodeRoots::initialize();
314
315 LogTarget(Trace, gc, region) lt;
316 if (lt.is_enabled()) {
317 ResourceMark rm;
318 LogStream ls(lt);
319 log_trace(gc, region)("All Regions");
320 print_heap_regions_on(&ls);
321 log_trace(gc, region)("Free Regions");
322 _free_set->print_on(&ls);
323 }
324
325 log_info(gc, init)("Safepointing mechanism: %s",
326 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
327 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
328
329 return JNI_OK;
330 }
331
332 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
333 CollectedHeap(),
334 _shenandoah_policy(policy),
335 _soft_ref_policy(),
336 _regions(NULL),
337 _free_set(NULL),
338 _collection_set(NULL),
339 _update_refs_iterator(this),
340 _bytes_allocated_since_gc_start(0),
341 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
342 _ref_processor(NULL),
343 _next_top_at_mark_starts(NULL),
344 _next_top_at_mark_starts_base(NULL),
345 _complete_top_at_mark_starts(NULL),
346 _complete_top_at_mark_starts_base(NULL),
347 _mark_bit_map0(),
348 _mark_bit_map1(),
349 _aux_bit_map(),
350 _connection_matrix(NULL),
351 _verifier(NULL),
352 _pacer(NULL),
353 _used_at_last_gc(0),
354 _alloc_seq_at_last_gc_start(0),
355 _alloc_seq_at_last_gc_end(0),
356 _safepoint_workers(NULL),
357 _gc_cycle_mode(),
358 #ifdef ASSERT
359 _heap_expansion_count(0),
360 #endif
361 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
362 _phase_timings(NULL),
363 _alloc_tracker(NULL),
364 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
365 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
366 _memory_pool(NULL)
367 {
368 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
369 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
370 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
371
372 _scm = new ShenandoahConcurrentMark();
373 _full_gc = new ShenandoahMarkCompact();
374 _used = 0;
375
376 _max_workers = MAX2(_max_workers, 1U);
377 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
378 /* are_GC_task_threads */true,
379 /* are_ConcurrentGC_threads */false);
380 if (_workers == NULL) {
381 vm_exit_during_initialization("Failed necessary allocation.");
382 } else {
383 _workers->initialize_workers();
384 }
385
386 if (ParallelSafepointCleanupThreads > 1) {
387 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
388 ParallelSafepointCleanupThreads,
389 false, false);
390 _safepoint_workers->initialize_workers();
391 }
392 }
393
394 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
395 private:
396 ShenandoahRegionIterator _regions;
397
398 public:
399 ShenandoahResetNextBitmapTask() :
400 AbstractGangTask("Parallel Reset Bitmap Task") {}
401
402 void work(uint worker_id) {
403 ShenandoahHeapRegion* region = _regions.next();
404 ShenandoahHeap* heap = ShenandoahHeap::heap();
405 while (region != NULL) {
406 if (heap->is_bitmap_slice_committed(region)) {
407 HeapWord* bottom = region->bottom();
408 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
409 if (top > bottom) {
410 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
411 }
412 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
413 }
414 region = _regions.next();
415 }
416 }
417 };
418
419 void ShenandoahHeap::reset_next_mark_bitmap() {
420 assert_gc_workers(_workers->active_workers());
421
422 ShenandoahResetNextBitmapTask task;
423 _workers->run_task(&task);
424 }
425
426 class ShenandoahResetNextBitmapTraversalTask : public AbstractGangTask {
427 private:
428 ShenandoahRegionIterator _regions;
429
430 public:
431 ShenandoahResetNextBitmapTraversalTask() :
432 AbstractGangTask("Parallel Reset Bitmap Task for Traversal") {}
433
434 void work(uint worker_id) {
435 ShenandoahHeap* heap = ShenandoahHeap::heap();
436 ShenandoahHeapRegionSet* traversal_set = heap->traversal_gc()->traversal_set();
437 ShenandoahHeapRegion* region = _regions.next();
438 while (region != NULL) {
439 if (heap->is_bitmap_slice_committed(region)) {
440 if (traversal_set->is_in(region) && !region->is_trash()) {
441 ShenandoahHeapLocker locker(heap->lock());
442 HeapWord* bottom = region->bottom();
443 HeapWord* top = heap->next_top_at_mark_start(bottom);
444 assert(top <= region->top(),
445 "TAMS must smaller/equals than top: TAMS: "PTR_FORMAT", top: "PTR_FORMAT,
446 p2i(top), p2i(region->top()));
447 if (top > bottom) {
448 heap->complete_mark_bit_map()->copy_from(heap->next_mark_bit_map(), MemRegion(bottom, top));
449 heap->set_complete_top_at_mark_start(bottom, top);
450 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
451 heap->set_next_top_at_mark_start(bottom, bottom);
452 }
453 }
454 assert(heap->is_next_bitmap_clear_range(region->bottom(), region->end()),
455 "need clear next bitmap");
456 }
457 region = _regions.next();
458 }
459 }
460 };
461
462 void ShenandoahHeap::reset_next_mark_bitmap_traversal() {
463 assert_gc_workers(_workers->active_workers());
464
465 ShenandoahResetNextBitmapTraversalTask task;
466 _workers->run_task(&task);
467 }
468
469 bool ShenandoahHeap::is_next_bitmap_clear() {
470 for (size_t idx = 0; idx < _num_regions; idx++) {
471 ShenandoahHeapRegion* r = get_region(idx);
472 if (is_bitmap_slice_committed(r) && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
473 return false;
474 }
475 }
476 return true;
477 }
478
479 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
480 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
481 }
482
483 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
484 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
485 }
486
487 void ShenandoahHeap::print_on(outputStream* st) const {
488 st->print_cr("Shenandoah Heap");
489 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
490 capacity() / K, committed() / K, used() / K);
491 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
492 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
493
494 st->print("Status: ");
495 if (has_forwarded_objects()) st->print("has forwarded objects, ");
496 if (is_concurrent_mark_in_progress()) st->print("marking, ");
497 if (is_evacuation_in_progress()) st->print("evacuating, ");
498 if (is_update_refs_in_progress()) st->print("updating refs, ");
499 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
500 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
501 if (is_full_gc_in_progress()) st->print("full gc, ");
502 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
503
504 if (cancelled_concgc()) {
505 st->print("conc gc cancelled");
506 } else {
507 st->print("not cancelled");
508 }
509 st->cr();
510
511 st->print_cr("Reserved region:");
512 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
513 p2i(reserved_region().start()),
514 p2i(reserved_region().end()));
515
516 if (UseShenandoahMatrix) {
517 st->print_cr("Matrix:");
518
519 ShenandoahConnectionMatrix* matrix = connection_matrix();
520 if (matrix != NULL) {
521 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
522 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
523 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
524 } else {
525 st->print_cr(" No matrix.");
526 }
527 }
528
529 if (Verbose) {
530 print_heap_regions_on(st);
531 }
532 }
533
534 class ShenandoahInitGCLABClosure : public ThreadClosure {
535 public:
536 void do_thread(Thread* thread) {
537 if (thread != NULL && (thread->is_Java_thread() || thread->is_Worker_thread() ||
538 thread->is_ConcurrentGC_thread())) {
539 thread->gclab().initialize(true);
540 }
541 }
542 };
543
544 void ShenandoahHeap::post_initialize() {
545 CollectedHeap::post_initialize();
546 if (UseTLAB) {
547 MutexLocker ml(Threads_lock);
548
549 ShenandoahInitGCLABClosure init_gclabs;
550 Threads::threads_do(&init_gclabs);
551 gc_threads_do(&init_gclabs);
552
553 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
554 // Now, we will let WorkGang to initialize gclab when new worker is created.
555 _workers->set_initialize_gclab();
556 }
557
558 _scm->initialize(_max_workers);
559 _full_gc->initialize(_gc_timer);
560
561 ref_processing_init();
562
563 _shenandoah_policy->post_heap_initialize();
564 }
565
566 size_t ShenandoahHeap::used() const {
567 return OrderAccess::load_acquire(&_used);
568 }
569
570 size_t ShenandoahHeap::committed() const {
571 OrderAccess::acquire();
572 return _committed;
573 }
574
575 void ShenandoahHeap::increase_committed(size_t bytes) {
576 assert_heaplock_or_safepoint();
577 _committed += bytes;
578 }
579
580 void ShenandoahHeap::decrease_committed(size_t bytes) {
581 assert_heaplock_or_safepoint();
582 _committed -= bytes;
583 }
584
585 void ShenandoahHeap::increase_used(size_t bytes) {
586 Atomic::add(bytes, &_used);
587 }
588
589 void ShenandoahHeap::set_used(size_t bytes) {
590 OrderAccess::release_store_fence(&_used, bytes);
591 }
592
593 void ShenandoahHeap::decrease_used(size_t bytes) {
594 assert(used() >= bytes, "never decrease heap size by more than we've left");
595 Atomic::add(-bytes, &_used);
596 }
597
598 void ShenandoahHeap::increase_allocated(size_t bytes) {
599 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
600 }
601
602 void ShenandoahHeap::notify_alloc(size_t words, bool waste) {
603 size_t bytes = words * HeapWordSize;
604 if (!waste) {
605 increase_used(bytes);
606 }
607 increase_allocated(bytes);
608 if (ShenandoahPacing) {
609 control_thread()->pacing_notify_alloc(words);
610 if (waste) {
611 pacer()->claim_for_alloc(words, true);
612 }
613 }
614 }
615
616 size_t ShenandoahHeap::capacity() const {
617 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
618 }
619
620 bool ShenandoahHeap::is_maximal_no_gc() const {
621 Unimplemented();
622 return true;
623 }
624
625 size_t ShenandoahHeap::max_capacity() const {
626 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
627 }
628
629 size_t ShenandoahHeap::initial_capacity() const {
630 return _initial_size;
631 }
632
633 bool ShenandoahHeap::is_in(const void* p) const {
634 HeapWord* heap_base = (HeapWord*) base();
635 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
636 return p >= heap_base && p < last_region_end;
637 }
638
639 bool ShenandoahHeap::is_scavengable(oop p) {
640 return true;
641 }
642
643 void ShenandoahHeap::handle_heap_shrinkage(double shrink_before) {
644 if (!ShenandoahUncommit) {
645 return;
646 }
647
648 ShenandoahHeapLocker locker(lock());
649
650 size_t count = 0;
651 for (size_t i = 0; i < num_regions(); i++) {
652 ShenandoahHeapRegion* r = get_region(i);
653 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
654 r->make_uncommitted();
655 count++;
656 }
657 }
658
659 if (count > 0) {
660 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
661 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
662 control_thread()->notify_heap_changed();
663 }
664 }
665
666 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
667 // Retain tlab and allocate object in shared space if
668 // the amount free in the tlab is too large to discard.
669 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
670 thread->gclab().record_slow_allocation(size);
671 return NULL;
672 }
673
674 // Discard gclab and allocate a new one.
675 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
676 size_t new_gclab_size = thread->gclab().compute_size(size);
677
678 thread->gclab().clear_before_allocation();
679
680 if (new_gclab_size == 0) {
681 return NULL;
682 }
683
684 // Allocate a new GCLAB...
685 HeapWord* obj = allocate_new_gclab(new_gclab_size);
686 if (obj == NULL) {
687 return NULL;
688 }
689
690 if (ZeroTLAB) {
691 // ..and clear it.
692 Copy::zero_to_words(obj, new_gclab_size);
693 } else {
694 // ...and zap just allocated object.
695 #ifdef ASSERT
696 // Skip mangling the space corresponding to the object header to
697 // ensure that the returned space is not considered parsable by
698 // any concurrent GC thread.
699 size_t hdr_size = oopDesc::header_size();
700 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
701 #endif // ASSERT
702 }
703 thread->gclab().fill(obj, obj + size, new_gclab_size);
704 return obj;
705 }
706
707 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
708 #ifdef ASSERT
709 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
710 #endif
711 return allocate_new_lab(word_size, _alloc_tlab);
712 }
713
714 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
715 #ifdef ASSERT
716 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
717 #endif
718 return allocate_new_lab(word_size, _alloc_gclab);
719 }
720
721 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
722 HeapWord* result = allocate_memory(word_size, type);
723
724 if (result != NULL) {
725 assert(! in_collection_set(result), "Never allocate in collection set");
726
727 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
728
729 }
730 return result;
731 }
732
733 ShenandoahHeap* ShenandoahHeap::heap() {
734 CollectedHeap* heap = Universe::heap();
735 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
736 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
737 return (ShenandoahHeap*) heap;
738 }
739
740 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
741 CollectedHeap* heap = Universe::heap();
742 return (ShenandoahHeap*) heap;
743 }
744
745 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
746 ShenandoahAllocTrace trace_alloc(word_size, type);
747
748 bool in_new_region = false;
749 HeapWord* result = NULL;
750
751 if (type == _alloc_tlab || type == _alloc_shared) {
752 if (ShenandoahPacing) {
753 pacer()->pace_for_alloc(word_size);
754 }
755
756 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
757 result = allocate_memory_under_lock(word_size, type, in_new_region);
758 }
759
760 // Allocation failed, try full-GC, then retry allocation.
761 //
762 // It might happen that one of the threads requesting allocation would unblock
763 // way later after full-GC happened, only to fail the second allocation, because
764 // other threads have already depleted the free storage. In this case, a better
765 // strategy would be to try full-GC again.
766 //
767 // Lacking the way to detect progress from "collect" call, we are left with blindly
768 // retrying for some bounded number of times.
769 // TODO: Poll if Full GC made enough progress to warrant retry.
770 int tries = 0;
771 while ((result == NULL) && (tries++ < ShenandoahAllocGCTries)) {
772 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing GC, try %d",
773 p2i(Thread::current()), word_size * HeapWordSize, tries);
774 control_thread()->handle_alloc_failure(word_size);
775 result = allocate_memory_under_lock(word_size, type, in_new_region);
776 }
777 } else {
778 assert(type == _alloc_gclab || type == _alloc_shared_gc, "Can only accept these types here");
779 result = allocate_memory_under_lock(word_size, type, in_new_region);
780 // Do not call handle_alloc_failure() here, because we cannot block.
781 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac().
782 }
783
784 if (in_new_region) {
785 control_thread()->notify_heap_changed();
786 }
787
788 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
789 word_size, p2i(result), Thread::current()->osthread()->thread_id());
790
791 if (result != NULL) {
792 notify_alloc(word_size, false);
793 }
794
795 return result;
796 }
797
798 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
799 ShenandoahHeapLocker locker(lock());
800 return _free_set->allocate(word_size, type, in_new_region);
801 }
802
803 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
804 bool* gc_overhead_limit_was_exceeded) {
805 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
806 HeapWord* result = filler + BrooksPointer::word_size();
807 if (filler != NULL) {
808 BrooksPointer::initialize(oop(result));
809
810 assert(! in_collection_set(result), "never allocate in targetted region");
811 return result;
812 } else {
813 return NULL;
814 }
815 }
816
817 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
818 private:
819 ShenandoahHeap* _heap;
820 Thread* _thread;
821 public:
822 ShenandoahEvacuateUpdateRootsClosure() :
823 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
824 }
825
826 private:
827 template <class T>
828 void do_oop_work(T* p) {
829 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
830
831 T o = RawAccess<>::oop_load(p);
832 if (! CompressedOops::is_null(o)) {
833 oop obj = CompressedOops::decode_not_null(o);
834 if (_heap->in_collection_set(obj)) {
835 shenandoah_assert_marked_complete(p, obj);
836 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
837 if (oopDesc::unsafe_equals(resolved, obj)) {
838 resolved = _heap->evacuate_object(obj, _thread);
839 }
840 RawAccess<OOP_NOT_NULL>::oop_store(p, resolved);
841 }
842 }
843 }
844
845 public:
846 void do_oop(oop* p) {
847 do_oop_work(p);
848 }
849 void do_oop(narrowOop* p) {
850 do_oop_work(p);
851 }
852 };
853
854 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
855 private:
856 ShenandoahHeap* _heap;
857 Thread* _thread;
858 public:
859 ShenandoahEvacuateRootsClosure() :
860 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
861 }
862
863 private:
864 template <class T>
865 void do_oop_work(T* p) {
866 T o = RawAccess<>::oop_load(p);
867 if (! CompressedOops::is_null(o)) {
868 oop obj = CompressedOops::decode_not_null(o);
869 if (_heap->in_collection_set(obj)) {
870 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
871 if (oopDesc::unsafe_equals(resolved, obj)) {
872 _heap->evacuate_object(obj, _thread);
873 }
874 }
875 }
876 }
877
878 public:
879 void do_oop(oop* p) {
880 do_oop_work(p);
881 }
882 void do_oop(narrowOop* p) {
883 do_oop_work(p);
884 }
885 };
886
887 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
888 private:
889 ShenandoahHeap* const _heap;
890 Thread* const _thread;
891 public:
892 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
893 _heap(heap), _thread(Thread::current()) {}
894
895 void do_object(oop p) {
896 shenandoah_assert_marked_complete(NULL, p);
897 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
898 _heap->evacuate_object(p, _thread);
899 }
900 }
901 };
902
903 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
904 private:
905 ShenandoahHeap* const _sh;
906 ShenandoahCollectionSet* const _cs;
907 ShenandoahSharedFlag _claimed_codecache;
908
909 public:
910 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
911 ShenandoahCollectionSet* cs) :
912 AbstractGangTask("Parallel Evacuation Task"),
913 _cs(cs),
914 _sh(sh)
915 {}
916
917 void work(uint worker_id) {
918
919 ShenandoahEvacOOMScope oom_evac_scope;
920 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
921
922 // If concurrent code cache evac is enabled, evacuate it here.
923 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
924 // nmethods. The update would be handled elsewhere.
925 if (ShenandoahConcurrentEvacCodeRoots && _claimed_codecache.try_set()) {
926 ShenandoahEvacuateRootsClosure cl;
927 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
928 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
929 CodeCache::blobs_do(&blobs);
930 }
931
932 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
933 ShenandoahHeapRegion* r;
934 while ((r =_cs->claim_next()) != NULL) {
935 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
936 worker_id,
937 r->region_number());
938
939 assert(r->has_live(), "all-garbage regions are reclaimed early");
940 _sh->marked_object_iterate(r, &cl);
941
942 if (_sh->check_cancelled_concgc_and_yield()) {
943 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
944 break;
945 }
946
947 if (ShenandoahPacing) {
948 _sh->pacer()->report_evac(r->get_live_data_words());
949 }
950 }
951 }
952 };
953
954 void ShenandoahHeap::trash_cset_regions() {
955 ShenandoahHeapLocker locker(lock());
956
957 ShenandoahCollectionSet* set = collection_set();
958 ShenandoahHeapRegion* r;
959 set->clear_current_index();
960 while ((r = set->next()) != NULL) {
961 r->make_trash();
962 }
963 collection_set()->clear();
964 }
965
966 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
967 st->print_cr("Heap Regions:");
968 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
969 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
970 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
971 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
972
973 for (size_t i = 0; i < num_regions(); i++) {
974 get_region(i)->print_on(st);
975 }
976 }
977
978 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
979 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
980
981 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
982 size_t size = humongous_obj->size() + BrooksPointer::word_size();
983 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
984 size_t index = start->region_number() + required_regions - 1;
985
986 assert(!start->has_live(), "liveness must be zero");
987 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
988
989 for(size_t i = 0; i < required_regions; i++) {
990 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
991 // as it expects that every region belongs to a humongous region starting with a humongous start region.
992 ShenandoahHeapRegion* region = get_region(index --);
993
994 LogTarget(Trace, gc, humongous) lt;
995 if (lt.is_enabled()) {
996 ResourceMark rm;
997 LogStream ls(lt);
998 region->print_on(&ls);
999 }
1000
1001 assert(region->is_humongous(), "expect correct humongous start or continuation");
1002 assert(!in_collection_set(region), "Humongous region should not be in collection set");
1003
1004 region->make_trash();
1005 }
1006 }
1007
1008 #ifdef ASSERT
1009 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
1010 bool heap_region_do(ShenandoahHeapRegion* r) {
1011 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
1012 return false;
1013 }
1014 };
1015 #endif
1016
1017 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
1018 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
1019
1020 if (!cancelled_concgc()) {
1021 // Allocations might have happened before we STWed here, record peak:
1022 shenandoahPolicy()->record_peak_occupancy();
1023
1024 make_tlabs_parsable(true);
1025
1026 if (ShenandoahVerify) {
1027 verifier()->verify_after_concmark();
1028 }
1029
1030 trash_cset_regions();
1031
1032 // NOTE: This needs to be done during a stop the world pause, because
1033 // putting regions into the collection set concurrently with Java threads
1034 // will create a race. In particular, acmp could fail because when we
1035 // resolve the first operand, the containing region might not yet be in
1036 // the collection set, and thus return the original oop. When the 2nd
1037 // operand gets resolved, the region could be in the collection set
1038 // and the oop gets evacuated. If both operands have originally been
1039 // the same, we get false negatives.
1040
1041 {
1042 ShenandoahHeapLocker locker(lock());
1043 _collection_set->clear();
1044 _free_set->clear();
1045
1046 #ifdef ASSERT
1047 ShenandoahCheckCollectionSetClosure ccsc;
1048 heap_region_iterate(&ccsc);
1049 #endif
1050
1051 _shenandoah_policy->choose_collection_set(_collection_set);
1052
1053 _free_set->rebuild();
1054 }
1055
1056 Universe::update_heap_info_at_gc();
1057
1058 if (ShenandoahVerify) {
1059 verifier()->verify_before_evacuation();
1060 }
1061 }
1062 }
1063
1064
1065 class ShenandoahRetireTLABClosure : public ThreadClosure {
1066 private:
1067 bool _retire;
1068
1069 public:
1070 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1071
1072 void do_thread(Thread* thread) {
1073 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1074 thread->gclab().make_parsable(_retire);
1075 }
1076 };
1077
1078 void ShenandoahHeap::make_tlabs_parsable(bool retire_tlabs) {
1079 if (UseTLAB) {
1080 CollectedHeap::ensure_parsability(retire_tlabs);
1081 ShenandoahRetireTLABClosure cl(retire_tlabs);
1082 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1083 cl.do_thread(t);
1084 }
1085 gc_threads_do(&cl);
1086 }
1087 }
1088
1089
1090 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1091 ShenandoahRootEvacuator* _rp;
1092 public:
1093
1094 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1095 AbstractGangTask("Shenandoah evacuate and update roots"),
1096 _rp(rp)
1097 {
1098 // Nothing else to do.
1099 }
1100
1101 void work(uint worker_id) {
1102 ShenandoahEvacOOMScope oom_evac_scope;
1103 ShenandoahEvacuateUpdateRootsClosure cl;
1104
1105 if (ShenandoahConcurrentEvacCodeRoots) {
1106 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1107 } else {
1108 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1109 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1110 }
1111 }
1112 };
1113
1114 class ShenandoahFixRootsTask : public AbstractGangTask {
1115 ShenandoahRootEvacuator* _rp;
1116 public:
1117
1118 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1119 AbstractGangTask("Shenandoah update roots"),
1120 _rp(rp)
1121 {
1122 // Nothing else to do.
1123 }
1124
1125 void work(uint worker_id) {
1126 ShenandoahEvacOOMScope oom_evac_scope;
1127 ShenandoahUpdateRefsClosure cl;
1128 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1129
1130 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1131 }
1132 };
1133
1134 void ShenandoahHeap::evacuate_and_update_roots() {
1135
1136 #if defined(COMPILER2) || INCLUDE_JVMCI
1137 DerivedPointerTable::clear();
1138 #endif
1139 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1140
1141 {
1142 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1143 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1144 workers()->run_task(&roots_task);
1145 }
1146
1147 #if defined(COMPILER2) || INCLUDE_JVMCI
1148 DerivedPointerTable::update_pointers();
1149 #endif
1150 if (cancelled_concgc()) {
1151 fixup_roots();
1152 }
1153 }
1154
1155 void ShenandoahHeap::fixup_roots() {
1156 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1157
1158 // If initial evacuation has been cancelled, we need to update all references
1159 // after all workers have finished. Otherwise we might run into the following problem:
1160 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1161 // GC thread 2 evacuates the same object X to to-space
1162 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1163 // clear() and update_pointers() must always be called in pairs,
1164 // cannot nest with above clear()/update_pointers().
1165 #if defined(COMPILER2) || INCLUDE_JVMCI
1166 DerivedPointerTable::clear();
1167 #endif
1168 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1169 ShenandoahFixRootsTask update_roots_task(&rp);
1170 workers()->run_task(&update_roots_task);
1171 #if defined(COMPILER2) || INCLUDE_JVMCI
1172 DerivedPointerTable::update_pointers();
1173 #endif
1174 }
1175
1176 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1177 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1178
1179 CodeBlobToOopClosure blobsCl(cl, false);
1180 CLDToOopClosure cldCl(cl);
1181
1182 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1183 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0);
1184 }
1185
1186 bool ShenandoahHeap::supports_tlab_allocation() const {
1187 return true;
1188 }
1189
1190 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1191 return MIN2(_free_set->unsafe_peek_free(), max_tlab_size());
1192 }
1193
1194 size_t ShenandoahHeap::max_tlab_size() const {
1195 return ShenandoahHeapRegion::max_tlab_size_bytes();
1196 }
1197
1198 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1199 public:
1200 void do_thread(Thread* thread) {
1201 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1202 thread->gclab().resize();
1203 }
1204 };
1205
1206 void ShenandoahHeap::resize_all_tlabs() {
1207 CollectedHeap::resize_all_tlabs();
1208
1209 ShenandoahResizeGCLABClosure cl;
1210 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1211 cl.do_thread(t);
1212 }
1213 gc_threads_do(&cl);
1214 }
1215
1216 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1217 public:
1218 void do_thread(Thread* thread) {
1219 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1220 thread->gclab().accumulate_statistics();
1221 thread->gclab().initialize_statistics();
1222 }
1223 };
1224
1225 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1226 ShenandoahAccumulateStatisticsGCLABClosure cl;
1227 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1228 cl.do_thread(t);
1229 }
1230 gc_threads_do(&cl);
1231 }
1232
1233 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1234 return true;
1235 }
1236
1237 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1238 // Overridden to do nothing.
1239 return new_obj;
1240 }
1241
1242 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1243 return true;
1244 }
1245
1246 bool ShenandoahHeap::card_mark_must_follow_store() const {
1247 return false;
1248 }
1249
1250 void ShenandoahHeap::collect(GCCause::Cause cause) {
1251 control_thread()->handle_explicit_gc(cause);
1252 }
1253
1254 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1255 //assert(false, "Shouldn't need to do full collections");
1256 }
1257
1258 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1259 Unimplemented();
1260 return NULL;
1261
1262 }
1263
1264 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1265 return _shenandoah_policy;
1266 }
1267
1268
1269 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1270 Space* sp = heap_region_containing(addr);
1271 if (sp != NULL) {
1272 return sp->block_start(addr);
1273 }
1274 return NULL;
1275 }
1276
1277 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1278 Space* sp = heap_region_containing(addr);
1279 assert(sp != NULL, "block_size of address outside of heap");
1280 return sp->block_size(addr);
1281 }
1282
1283 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1284 Space* sp = heap_region_containing(addr);
1285 return sp->block_is_obj(addr);
1286 }
1287
1288 jlong ShenandoahHeap::millis_since_last_gc() {
1289 return 0;
1290 }
1291
1292 void ShenandoahHeap::prepare_for_verify() {
1293 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1294 make_tlabs_parsable(false);
1295 }
1296 }
1297
1298 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1299 workers()->print_worker_threads_on(st);
1300 if (ShenandoahStringDedup::is_enabled()) {
1301 ShenandoahStringDedup::print_worker_threads_on(st);
1302 }
1303 }
1304
1305 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1306 workers()->threads_do(tcl);
1307 if (ShenandoahStringDedup::is_enabled()) {
1308 ShenandoahStringDedup::threads_do(tcl);
1309 }
1310 }
1311
1312 void ShenandoahHeap::print_tracing_info() const {
1313 LogTarget(Info, gc, stats) lt;
1314 if (lt.is_enabled()) {
1315 ResourceMark rm;
1316 LogStream ls(lt);
1317
1318 phase_timings()->print_on(&ls);
1319
1320 ls.cr();
1321 ls.cr();
1322
1323 shenandoahPolicy()->print_gc_stats(&ls);
1324
1325 ls.cr();
1326 ls.cr();
1327
1328 if (ShenandoahPacing) {
1329 pacer()->print_on(&ls);
1330 }
1331
1332 ls.cr();
1333 ls.cr();
1334
1335 if (ShenandoahAllocationTrace) {
1336 assert(alloc_tracker() != NULL, "Must be");
1337 alloc_tracker()->print_on(&ls);
1338 } else {
1339 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1340 }
1341 }
1342 }
1343
1344 void ShenandoahHeap::verify(VerifyOption vo) {
1345 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1346 if (ShenandoahVerify) {
1347 verifier()->verify_generic(vo);
1348 } else {
1349 // TODO: Consider allocating verification bitmaps on demand,
1350 // and turn this on unconditionally.
1351 }
1352 }
1353 }
1354 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1355 return _free_set->capacity();
1356 }
1357
1358 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1359 private:
1360 MarkBitMap* _bitmap;
1361 Stack<oop,mtGC>* _oop_stack;
1362
1363 template <class T>
1364 void do_oop_work(T* p) {
1365 T o = RawAccess<>::oop_load(p);
1366 if (!CompressedOops::is_null(o)) {
1367 oop obj = CompressedOops::decode_not_null(o);
1368 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1369 assert(oopDesc::is_oop(obj), "must be a valid oop");
1370 if (!_bitmap->isMarked((HeapWord*) obj)) {
1371 _bitmap->mark((HeapWord*) obj);
1372 _oop_stack->push(obj);
1373 }
1374 }
1375 }
1376 public:
1377 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1378 _bitmap(bitmap), _oop_stack(oop_stack) {}
1379 void do_oop(oop* p) { do_oop_work(p); }
1380 void do_oop(narrowOop* p) { do_oop_work(p); }
1381 };
1382
1383 /*
1384 * This is public API, used in preparation of object_iterate().
1385 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1386 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1387 * control, we call SH::make_tlabs_parsable().
1388 */
1389 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1390 // No-op.
1391 }
1392
1393 /*
1394 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1395 *
1396 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1397 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1398 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1399 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1400 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1401 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1402 * wiped the bitmap in preparation for next marking).
1403 *
1404 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1405 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1406 * is allowed to report dead objects, but is not required to do so.
1407 */
1408 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1409 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1410 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1411 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1412 return;
1413 }
1414
1415 Stack<oop,mtGC> oop_stack;
1416
1417 // First, we process all GC roots. This populates the work stack with initial objects.
1418 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1419 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1420 CLDToOopClosure clds(&oops, false);
1421 CodeBlobToOopClosure blobs(&oops, false);
1422 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0);
1423
1424 // Work through the oop stack to traverse heap.
1425 while (! oop_stack.is_empty()) {
1426 oop obj = oop_stack.pop();
1427 assert(oopDesc::is_oop(obj), "must be a valid oop");
1428 cl->do_object(obj);
1429 obj->oop_iterate(&oops);
1430 }
1431
1432 assert(oop_stack.is_empty(), "should be empty");
1433
1434 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1435 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1436 }
1437 }
1438
1439 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1440 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1441 object_iterate(cl);
1442 }
1443
1444 // Apply blk->heap_region_do() on all committed regions in address order,
1445 // terminating the iteration early if heap_region_do() returns true.
1446 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1447 for (size_t i = 0; i < num_regions(); i++) {
1448 ShenandoahHeapRegion* current = get_region(i);
1449 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1450 continue;
1451 }
1452 if (skip_cset_regions && in_collection_set(current)) {
1453 continue;
1454 }
1455 if (blk->heap_region_do(current)) {
1456 return;
1457 }
1458 }
1459 }
1460
1461 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1462 private:
1463 ShenandoahHeap* sh;
1464 public:
1465 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1466
1467 bool heap_region_do(ShenandoahHeapRegion* r) {
1468 r->clear_live_data();
1469 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1470 return false;
1471 }
1472 };
1473
1474 void ShenandoahHeap::op_init_mark() {
1475 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1476
1477 assert(is_next_bitmap_clear(), "need clear marking bitmap");
1478
1479 if (ShenandoahVerify) {
1480 verifier()->verify_before_concmark();
1481 }
1482
1483 {
1484 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1485 accumulate_statistics_all_tlabs();
1486 }
1487
1488 set_concurrent_mark_in_progress(true);
1489 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1490 if (UseTLAB) {
1491 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1492 make_tlabs_parsable(true);
1493 }
1494
1495 {
1496 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1497 ShenandoahClearLivenessClosure clc(this);
1498 heap_region_iterate(&clc);
1499 }
1500
1501 // Make above changes visible to worker threads
1502 OrderAccess::fence();
1503
1504 concurrentMark()->init_mark_roots();
1505
1506 if (UseTLAB) {
1507 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1508 resize_all_tlabs();
1509 }
1510
1511 if (ShenandoahPacing) {
1512 pacer()->setup_for_mark();
1513 }
1514 }
1515
1516 void ShenandoahHeap::op_mark() {
1517 concurrentMark()->mark_from_roots();
1518
1519 // Allocations happen during concurrent mark, record peak after the phase:
1520 shenandoahPolicy()->record_peak_occupancy();
1521 }
1522
1523 void ShenandoahHeap::op_final_mark() {
1524 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1525
1526 // It is critical that we
1527 // evacuate roots right after finishing marking, so that we don't
1528 // get unmarked objects in the roots.
1529
1530 if (! cancelled_concgc()) {
1531 concurrentMark()->finish_mark_from_roots();
1532 stop_concurrent_marking();
1533
1534 {
1535 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1536 prepare_for_concurrent_evacuation();
1537 }
1538
1539 // If collection set has candidates, start evacuation.
1540 // Otherwise, bypass the rest of the cycle.
1541 if (!collection_set()->is_empty()) {
1542 set_evacuation_in_progress(true);
1543 // From here on, we need to update references.
1544 set_has_forwarded_objects(true);
1545
1546 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1547 evacuate_and_update_roots();
1548 }
1549
1550 if (ShenandoahPacing) {
1551 pacer()->setup_for_evac();
1552 }
1553 } else {
1554 concurrentMark()->cancel();
1555 stop_concurrent_marking();
1556
1557 if (process_references()) {
1558 // Abandon reference processing right away: pre-cleaning must have failed.
1559 ReferenceProcessor *rp = ref_processor();
1560 rp->disable_discovery();
1561 rp->abandon_partial_discovery();
1562 rp->verify_no_references_recorded();
1563 }
1564 }
1565 }
1566
1567 void ShenandoahHeap::op_final_evac() {
1568 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1569
1570 set_evacuation_in_progress(false);
1571 if (ShenandoahVerify) {
1572 verifier()->verify_after_evacuation();
1573 }
1574 }
1575
1576 void ShenandoahHeap::op_evac() {
1577
1578 LogTarget(Trace, gc, region) lt_region;
1579 LogTarget(Trace, gc, cset) lt_cset;
1580
1581 if (lt_region.is_enabled()) {
1582 ResourceMark rm;
1583 LogStream ls(lt_region);
1584 ls.print_cr("All available regions:");
1585 print_heap_regions_on(&ls);
1586 }
1587
1588 if (lt_cset.is_enabled()) {
1589 ResourceMark rm;
1590 LogStream ls(lt_cset);
1591 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1592 _collection_set->print_on(&ls);
1593
1594 ls.print_cr("Free set:");
1595 _free_set->print_on(&ls);
1596 }
1597
1598 ShenandoahParallelEvacuationTask task(this, _collection_set);
1599 workers()->run_task(&task);
1600
1601 if (lt_cset.is_enabled()) {
1602 ResourceMark rm;
1603 LogStream ls(lt_cset);
1604 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1605 _collection_set->count());
1606 _collection_set->print_on(&ls);
1607
1608 ls.print_cr("After evacuation free set:");
1609 _free_set->print_on(&ls);
1610 }
1611
1612 if (lt_region.is_enabled()) {
1613 ResourceMark rm;
1614 LogStream ls(lt_region);
1615 ls.print_cr("All regions after evacuation:");
1616 print_heap_regions_on(&ls);
1617 }
1618
1619 // Allocations happen during evacuation, record peak after the phase:
1620 shenandoahPolicy()->record_peak_occupancy();
1621 }
1622
1623 void ShenandoahHeap::op_updaterefs() {
1624 update_heap_references(true);
1625
1626 // Allocations happen during update-refs, record peak after the phase:
1627 shenandoahPolicy()->record_peak_occupancy();
1628 }
1629
1630 void ShenandoahHeap::op_cleanup() {
1631 ShenandoahGCPhase phase_recycle(ShenandoahPhaseTimings::conc_cleanup_recycle);
1632 free_set()->recycle_trash();
1633
1634 // Allocations happen during cleanup, record peak after the phase:
1635 shenandoahPolicy()->record_peak_occupancy();
1636 }
1637
1638 void ShenandoahHeap::op_cleanup_bitmaps() {
1639 op_cleanup();
1640
1641 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1642 reset_next_mark_bitmap();
1643
1644 // Allocations happen during bitmap cleanup, record peak after the phase:
1645 shenandoahPolicy()->record_peak_occupancy();
1646 }
1647
1648 void ShenandoahHeap::op_cleanup_traversal() {
1649
1650 {
1651 ShenandoahGCPhase phase_reset(ShenandoahPhaseTimings::conc_cleanup_reset_bitmaps);
1652 reset_next_mark_bitmap_traversal();
1653 }
1654
1655 op_cleanup();
1656
1657 // Allocations happen during bitmap cleanup, record peak after the phase:
1658 shenandoahPolicy()->record_peak_occupancy();
1659 }
1660
1661 void ShenandoahHeap::op_preclean() {
1662 concurrentMark()->preclean_weak_refs();
1663
1664 // Allocations happen during concurrent preclean, record peak after the phase:
1665 shenandoahPolicy()->record_peak_occupancy();
1666 }
1667
1668 void ShenandoahHeap::op_init_traversal() {
1669 traversal_gc()->init_traversal_collection();
1670 }
1671
1672 void ShenandoahHeap::op_traversal() {
1673 traversal_gc()->concurrent_traversal_collection();
1674 }
1675
1676 void ShenandoahHeap::op_final_traversal() {
1677 traversal_gc()->final_traversal_collection();
1678 }
1679
1680 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1681 full_gc()->do_it(cause);
1682 }
1683
1684 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1685 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1686 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1687 // some phase, we have to upgrade the Degenerate GC to Full GC.
1688
1689 clear_cancelled_concgc();
1690
1691 size_t used_before = used();
1692
1693 switch (point) {
1694 case _degenerated_evac:
1695 // Not possible to degenerate from here, upgrade to Full GC right away.
1696 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1697 op_degenerated_fail();
1698 return;
1699
1700 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1701 // but enters it at different points, depending on which concurrent phase had
1702 // degenerated.
1703
1704 case _degenerated_traversal:
1705 {
1706 ShenandoahHeapLocker locker(lock());
1707 collection_set()->clear_current_index();
1708 for (size_t i = 0; i < collection_set()->count(); i++) {
1709 ShenandoahHeapRegion* r = collection_set()->next();
1710 r->make_regular_bypass();
1711 }
1712 collection_set()->clear();
1713 }
1714 op_final_traversal();
1715 op_cleanup_traversal();
1716 return;
1717
1718 case _degenerated_outside_cycle:
1719 if (shenandoahPolicy()->can_do_traversal_gc()) {
1720 // Not possible to degenerate from here, upgrade to Full GC right away.
1721 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1722 op_degenerated_fail();
1723 return;
1724 }
1725 op_init_mark();
1726 if (cancelled_concgc()) {
1727 op_degenerated_fail();
1728 return;
1729 }
1730
1731 case _degenerated_mark:
1732 op_final_mark();
1733 if (cancelled_concgc()) {
1734 op_degenerated_fail();
1735 return;
1736 }
1737
1738 op_cleanup();
1739
1740 // If heuristics thinks we should do the cycle, this flag would be set,
1741 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1742 if (is_evacuation_in_progress()) {
1743 op_evac();
1744 if (cancelled_concgc()) {
1745 op_degenerated_fail();
1746 return;
1747 }
1748 }
1749
1750 // If heuristics thinks we should do the cycle, this flag would be set,
1751 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1752 if (has_forwarded_objects()) {
1753 op_init_updaterefs();
1754 if (cancelled_concgc()) {
1755 op_degenerated_fail();
1756 return;
1757 }
1758 }
1759
1760 case _degenerated_updaterefs:
1761 if (has_forwarded_objects()) {
1762 op_final_updaterefs();
1763 if (cancelled_concgc()) {
1764 op_degenerated_fail();
1765 return;
1766 }
1767 }
1768
1769 op_cleanup_bitmaps();
1770 break;
1771
1772 default:
1773 ShouldNotReachHere();
1774 }
1775
1776 if (ShenandoahVerify) {
1777 verifier()->verify_after_degenerated();
1778 }
1779
1780 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1781 // because that probably means the heap is overloaded and/or fragmented.
1782 size_t used_after = used();
1783 size_t difference = (used_before > used_after) ? used_before - used_after : 0;
1784 if (difference < ShenandoahHeapRegion::region_size_words()) {
1785 cancel_concgc(GCCause::_shenandoah_upgrade_to_full_gc);
1786 op_degenerated_futile();
1787 }
1788 }
1789
1790 void ShenandoahHeap::op_degenerated_fail() {
1791 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1792 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1793 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1794 }
1795
1796 void ShenandoahHeap::op_degenerated_futile() {
1797 log_info(gc)("Degenerated GC had not reclaimed enough, upgrading to Full GC");
1798 shenandoahPolicy()->record_degenerated_upgrade_to_full();
1799 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1800 }
1801
1802 void ShenandoahHeap::swap_mark_bitmaps() {
1803 // Swap bitmaps.
1804 MarkBitMap* tmp1 = _complete_mark_bit_map;
1805 _complete_mark_bit_map = _next_mark_bit_map;
1806 _next_mark_bit_map = tmp1;
1807
1808 // Swap top-at-mark-start pointers
1809 HeapWord** tmp2 = _complete_top_at_mark_starts;
1810 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1811 _next_top_at_mark_starts = tmp2;
1812
1813 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1814 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1815 _next_top_at_mark_starts_base = tmp3;
1816 }
1817
1818
1819 void ShenandoahHeap::stop_concurrent_marking() {
1820 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1821 if (! cancelled_concgc()) {
1822 // If we needed to update refs, and concurrent marking has been cancelled,
1823 // we need to finish updating references.
1824 set_has_forwarded_objects(false);
1825 swap_mark_bitmaps();
1826 }
1827 set_concurrent_mark_in_progress(false);
1828
1829 LogTarget(Trace, gc, region) lt;
1830 if (lt.is_enabled()) {
1831 ResourceMark rm;
1832 LogStream ls(lt);
1833 ls.print_cr("Regions at stopping the concurrent mark:");
1834 print_heap_regions_on(&ls);
1835 }
1836 }
1837
1838 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1839 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1840 ShenandoahThreadLocalData::set_gc_state(t, state);
1841 }
1842 }
1843
1844 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1845 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1846 _gc_state.set_cond(mask, value);
1847 set_gc_state_all_threads(_gc_state.raw_value());
1848 }
1849
1850 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1851 set_gc_state_mask(MARKING, in_progress);
1852 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1853 }
1854
1855 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1856 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED, in_progress);
1857 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1858 }
1859
1860 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1861 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1862 set_gc_state_mask(EVACUATION, in_progress);
1863 }
1864
1865 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1866 // Initialize Brooks pointer for the next object
1867 HeapWord* result = obj + BrooksPointer::word_size();
1868 BrooksPointer::initialize(oop(result));
1869 return result;
1870 }
1871
1872 uint ShenandoahHeap::oop_extra_words() {
1873 return BrooksPointer::word_size();
1874 }
1875
1876 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1877 _heap(ShenandoahHeap::heap_no_check()) {
1878 }
1879
1880 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1881 _heap(ShenandoahHeap::heap_no_check()) {
1882 }
1883
1884 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1885 if (CompressedOops::is_null(obj)) {
1886 return false;
1887 }
1888 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1889 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_mark_in_progress() || _heap->is_concurrent_traversal_in_progress())
1890 return _heap->is_marked_next(obj);
1891 }
1892
1893 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1894 if (CompressedOops::is_null(obj)) {
1895 return false;
1896 }
1897 shenandoah_assert_not_forwarded(NULL, obj);
1898 return _heap->is_marked_next(obj);
1899 }
1900
1901 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1902 return has_forwarded_objects() ?
1903 (BoolObjectClosure*) &_forwarded_is_alive :
1904 (BoolObjectClosure*) &_is_alive;
1905 }
1906
1907 void ShenandoahHeap::ref_processing_init() {
1908 MemRegion mr = reserved_region();
1909
1910 _forwarded_is_alive.init(this);
1911 _is_alive.init(this);
1912 assert(_max_workers > 0, "Sanity");
1913
1914 _ref_processor =
1915 new ReferenceProcessor(mr, // span
1916 ParallelRefProcEnabled, // MT processing
1917 _max_workers, // Degree of MT processing
1918 true, // MT discovery
1919 _max_workers, // Degree of MT discovery
1920 false, // Reference discovery is not atomic
1921 NULL); // No closure, should be installed before use
1922
1923 shenandoah_assert_rp_isalive_not_installed();
1924 }
1925
1926
1927 GCTracer* ShenandoahHeap::tracer() {
1928 return shenandoahPolicy()->tracer();
1929 }
1930
1931 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1932 return _free_set->used();
1933 }
1934
1935 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1936 if (try_cancel_concgc()) {
1937 FormatBuffer<> msg("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1938 log_info(gc)("%s", msg.buffer());
1939 Events::log(Thread::current(), "%s", msg.buffer());
1940 }
1941 }
1942
1943 uint ShenandoahHeap::max_workers() {
1944 return _max_workers;
1945 }
1946
1947 void ShenandoahHeap::stop() {
1948 // The shutdown sequence should be able to terminate when GC is running.
1949
1950 // Step 0. Notify policy to disable event recording.
1951 _shenandoah_policy->record_shutdown();
1952
1953 // Step 1. Notify control thread that we are in shutdown.
1954 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1955 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1956 control_thread()->prepare_for_graceful_shutdown();
1957
1958 // Step 2. Notify GC workers that we are cancelling GC.
1959 cancel_concgc(GCCause::_shenandoah_stop_vm);
1960
1961 // Step 3. Wait until GC worker exits normally.
1962 control_thread()->stop();
1963
1964 // Step 4. Stop String Dedup thread if it is active
1965 if (ShenandoahStringDedup::is_enabled()) {
1966 ShenandoahStringDedup::stop();
1967 }
1968 }
1969
1970 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1971 ShenandoahPhaseTimings::Phase phase_root =
1972 full_gc ?
1973 ShenandoahPhaseTimings::full_gc_purge :
1974 ShenandoahPhaseTimings::purge;
1975
1976 ShenandoahPhaseTimings::Phase phase_unload =
1977 full_gc ?
1978 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1979 ShenandoahPhaseTimings::purge_class_unload;
1980
1981 ShenandoahPhaseTimings::Phase phase_cldg =
1982 full_gc ?
1983 ShenandoahPhaseTimings::full_gc_purge_cldg :
1984 ShenandoahPhaseTimings::purge_cldg;
1985
1986 ShenandoahPhaseTimings::Phase phase_par =
1987 full_gc ?
1988 ShenandoahPhaseTimings::full_gc_purge_par :
1989 ShenandoahPhaseTimings::purge_par;
1990
1991 ShenandoahPhaseTimings::Phase phase_par_classes =
1992 full_gc ?
1993 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1994 ShenandoahPhaseTimings::purge_par_classes;
1995
1996 ShenandoahPhaseTimings::Phase phase_par_codecache =
1997 full_gc ?
1998 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1999 ShenandoahPhaseTimings::purge_par_codecache;
2000
2001 ShenandoahPhaseTimings::Phase phase_par_rmt =
2002 full_gc ?
2003 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
2004 ShenandoahPhaseTimings::purge_par_rmt;
2005
2006 ShenandoahPhaseTimings::Phase phase_par_symbstring =
2007 full_gc ?
2008 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
2009 ShenandoahPhaseTimings::purge_par_symbstring;
2010
2011 ShenandoahPhaseTimings::Phase phase_par_sync =
2012 full_gc ?
2013 ShenandoahPhaseTimings::full_gc_purge_par_sync :
2014 ShenandoahPhaseTimings::purge_par_sync;
2015
2016 ShenandoahGCPhase root_phase(phase_root);
2017
2018 BoolObjectClosure* is_alive = is_alive_closure();
2019
2020 bool purged_class;
2021
2022 // Unload classes and purge SystemDictionary.
2023 {
2024 ShenandoahGCPhase phase(phase_unload);
2025 purged_class = SystemDictionary::do_unloading(is_alive,
2026 gc_timer(),
2027 false /* defer cleaning */);
2028 }
2029
2030 {
2031 ShenandoahGCPhase phase(phase_par);
2032 uint active = _workers->active_workers();
2033 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
2034 _workers->run_task(&unlink_task);
2035
2036 ShenandoahPhaseTimings* p = phase_timings();
2037 ParallelCleaningTimes times = unlink_task.times();
2038
2039 // "times" report total time, phase_tables_cc reports wall time. Divide total times
2040 // by active workers to get average time per worker, that would add up to wall time.
2041 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
2042 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
2043 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
2044 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
2045 p->record_phase_time(phase_par_sync, times.sync_us() / active);
2046 }
2047
2048 if (ShenandoahStringDedup::is_enabled()) {
2049 ShenandoahPhaseTimings::Phase phase_par_string_dedup =
2050 full_gc ?
2051 ShenandoahPhaseTimings::full_gc_purge_par_string_dedup :
2052 ShenandoahPhaseTimings::purge_par_string_dedup;
2053 ShenandoahGCPhase phase(phase_par_string_dedup);
2054 ShenandoahStringDedup::parallel_cleanup();
2055 }
2056
2057
2058 {
2059 ShenandoahGCPhase phase(phase_cldg);
2060 ClassLoaderDataGraph::purge();
2061 }
2062 }
2063
2064 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2065 set_gc_state_mask(HAS_FORWARDED, cond);
2066 }
2067
2068 void ShenandoahHeap::set_process_references(bool pr) {
2069 _process_references.set_cond(pr);
2070 }
2071
2072 void ShenandoahHeap::set_unload_classes(bool uc) {
2073 _unload_classes.set_cond(uc);
2074 }
2075
2076 bool ShenandoahHeap::process_references() const {
2077 return _process_references.is_set();
2078 }
2079
2080 bool ShenandoahHeap::unload_classes() const {
2081 return _unload_classes.is_set();
2082 }
2083
2084 //fixme this should be in heapregionset
2085 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
2086 size_t region_idx = r->region_number() + 1;
2087 ShenandoahHeapRegion* next = get_region(region_idx);
2088 guarantee(next->region_number() == region_idx, "region number must match");
2089 while (next->is_humongous()) {
2090 region_idx = next->region_number() + 1;
2091 next = get_region(region_idx);
2092 guarantee(next->region_number() == region_idx, "region number must match");
2093 }
2094 return next;
2095 }
2096
2097 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
2098 return _monitoring_support;
2099 }
2100
2101 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
2102 return _complete_mark_bit_map;
2103 }
2104
2105 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
2106 return _next_mark_bit_map;
2107 }
2108
2109 address ShenandoahHeap::in_cset_fast_test_addr() {
2110 ShenandoahHeap* heap = ShenandoahHeap::heap();
2111 assert(heap->collection_set() != NULL, "Sanity");
2112 return (address) heap->collection_set()->biased_map_address();
2113 }
2114
2115 address ShenandoahHeap::cancelled_concgc_addr() {
2116 return (address) ShenandoahHeap::heap()->_cancelled_concgc.addr_of();
2117 }
2118
2119 address ShenandoahHeap::gc_state_addr() {
2120 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2121 }
2122
2123 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2124 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2125 }
2126
2127 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2128 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2129 }
2130
2131 ShenandoahPacer* ShenandoahHeap::pacer() const {
2132 assert (_pacer != NULL, "sanity");
2133 return _pacer;
2134 }
2135
2136 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2137 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2138 _next_top_at_mark_starts[index] = addr;
2139 }
2140
2141 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
2142 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2143 return _next_top_at_mark_starts[index];
2144 }
2145
2146 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
2147 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2148 _complete_top_at_mark_starts[index] = addr;
2149 }
2150
2151 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
2152 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
2153 return _complete_top_at_mark_starts[index];
2154 }
2155
2156 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2157 _degenerated_gc_in_progress.set_cond(in_progress);
2158 }
2159
2160 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2161 _full_gc_in_progress.set_cond(in_progress);
2162 }
2163
2164 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2165 assert (is_full_gc_in_progress(), "should be");
2166 _full_gc_move_in_progress.set_cond(in_progress);
2167 }
2168
2169 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2170 set_gc_state_mask(UPDATEREFS, in_progress);
2171 }
2172
2173 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2174 ShenandoahCodeRoots::add_nmethod(nm);
2175 }
2176
2177 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2178 ShenandoahCodeRoots::remove_nmethod(nm);
2179 }
2180
2181 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2182 o = BarrierSet::barrier_set()->write_barrier(o);
2183 ShenandoahHeapLocker locker(lock());
2184 heap_region_containing(o)->make_pinned();
2185 return o;
2186 }
2187
2188 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2189 o = BarrierSet::barrier_set()->read_barrier(o);
2190 ShenandoahHeapLocker locker(lock());
2191 heap_region_containing(o)->make_unpinned();
2192 }
2193
2194 GCTimer* ShenandoahHeap::gc_timer() const {
2195 return _gc_timer;
2196 }
2197
2198 #ifdef ASSERT
2199 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2200 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2201
2202 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2203 if (UseDynamicNumberOfGCThreads ||
2204 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2205 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2206 } else {
2207 // Use ParallelGCThreads inside safepoints
2208 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2209 }
2210 } else {
2211 if (UseDynamicNumberOfGCThreads ||
2212 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2213 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2214 } else {
2215 // Use ConcGCThreads outside safepoints
2216 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2217 }
2218 }
2219 }
2220 #endif
2221
2222 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
2223 return _connection_matrix;
2224 }
2225
2226 ShenandoahTraversalGC* ShenandoahHeap::traversal_gc() {
2227 return _traversal_gc;
2228 }
2229
2230 ShenandoahVerifier* ShenandoahHeap::verifier() {
2231 guarantee(ShenandoahVerify, "Should be enabled");
2232 assert (_verifier != NULL, "sanity");
2233 return _verifier;
2234 }
2235
2236 template<class T>
2237 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2238 private:
2239 T cl;
2240 ShenandoahHeap* _heap;
2241 ShenandoahRegionIterator* _regions;
2242 bool _concurrent;
2243 public:
2244 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2245 AbstractGangTask("Concurrent Update References Task"),
2246 cl(T()),
2247 _heap(ShenandoahHeap::heap()),
2248 _regions(regions),
2249 _concurrent(concurrent) {
2250 }
2251
2252 void work(uint worker_id) {
2253 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2254 ShenandoahHeapRegion* r = _regions->next();
2255 while (r != NULL) {
2256 if (_heap->in_collection_set(r)) {
2257 HeapWord* bottom = r->bottom();
2258 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2259 if (top > bottom) {
2260 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2261 }
2262 } else {
2263 if (r->is_active()) {
2264 _heap->marked_object_oop_safe_iterate(r, &cl);
2265 if (ShenandoahPacing) {
2266 _heap->pacer()->report_updaterefs(r->get_live_data_words());
2267 }
2268 }
2269 }
2270 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
2271 return;
2272 }
2273 r = _regions->next();
2274 }
2275 }
2276 };
2277
2278 void ShenandoahHeap::update_heap_references(bool concurrent) {
2279 if (UseShenandoahMatrix) {
2280 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(&_update_refs_iterator, concurrent);
2281 workers()->run_task(&task);
2282 } else {
2283 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2284 workers()->run_task(&task);
2285 }
2286 }
2287
2288 void ShenandoahHeap::op_init_updaterefs() {
2289 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2290
2291 if (ShenandoahVerify) {
2292 verifier()->verify_before_updaterefs();
2293 }
2294
2295 set_evacuation_in_progress(false);
2296 set_update_refs_in_progress(true);
2297 make_tlabs_parsable(true);
2298 if (UseShenandoahMatrix) {
2299 connection_matrix()->clear_all();
2300 }
2301 for (uint i = 0; i < num_regions(); i++) {
2302 ShenandoahHeapRegion* r = get_region(i);
2303 r->set_concurrent_iteration_safe_limit(r->top());
2304 }
2305
2306 // Reset iterator.
2307 _update_refs_iterator = ShenandoahRegionIterator();
2308
2309 if (ShenandoahPacing) {
2310 pacer()->setup_for_updaterefs();
2311 }
2312 }
2313
2314 void ShenandoahHeap::op_final_updaterefs() {
2315 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2316
2317 // Check if there is left-over work, and finish it
2318 if (_update_refs_iterator.has_next()) {
2319 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2320
2321 // Finish updating references where we left off.
2322 clear_cancelled_concgc();
2323 update_heap_references(false);
2324 }
2325
2326 // Clear cancelled conc GC, if set. On cancellation path, the block before would handle
2327 // everything. On degenerated paths, cancelled gc would not be set anyway.
2328 if (cancelled_concgc()) {
2329 clear_cancelled_concgc();
2330 }
2331 assert(!cancelled_concgc(), "Should have been done right before");
2332
2333 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2334
2335 // Allocations might have happened before we STWed here, record peak:
2336 shenandoahPolicy()->record_peak_occupancy();
2337
2338 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2339
2340 trash_cset_regions();
2341 set_has_forwarded_objects(false);
2342
2343 if (ShenandoahVerify) {
2344 verifier()->verify_after_updaterefs();
2345 }
2346
2347 {
2348 ShenandoahHeapLocker locker(lock());
2349 _free_set->rebuild();
2350 }
2351
2352 set_update_refs_in_progress(false);
2353 }
2354
2355 void ShenandoahHeap::set_alloc_seq_gc_start() {
2356 // Take next number, the start seq number is inclusive
2357 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::seqnum_current_alloc() + 1;
2358 }
2359
2360 void ShenandoahHeap::set_alloc_seq_gc_end() {
2361 // Take current number, the end seq number is also inclusive
2362 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::seqnum_current_alloc();
2363 }
2364
2365
2366 #ifdef ASSERT
2367 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2368 _lock.assert_owned_by_current_thread();
2369 }
2370
2371 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2372 _lock.assert_not_owned_by_current_thread();
2373 }
2374
2375 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2376 _lock.assert_owned_by_current_thread_or_safepoint();
2377 }
2378 #endif
2379
2380 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2381 print_on(st);
2382 print_heap_regions_on(st);
2383 }
2384
2385 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2386 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2387
2388 size_t regions_from = _bitmap_regions_per_slice * slice;
2389 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2390 for (size_t g = regions_from; g < regions_to; g++) {
2391 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2392 if (skip_self && g == r->region_number()) continue;
2393 if (get_region(g)->is_committed()) {
2394 return true;
2395 }
2396 }
2397 return false;
2398 }
2399
2400 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2401 assert_heaplock_owned_by_current_thread();
2402
2403 if (is_bitmap_slice_committed(r, true)) {
2404 // Some other region from the group is already committed, meaning the bitmap
2405 // slice is already committed, we exit right away.
2406 return true;
2407 }
2408
2409 // Commit the bitmap slice:
2410 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2411 size_t off = _bitmap_bytes_per_slice * slice;
2412 size_t len = _bitmap_bytes_per_slice;
2413 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2414 return false;
2415 }
2416 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2417 return false;
2418 }
2419 return true;
2420 }
2421
2422 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2423 assert_heaplock_owned_by_current_thread();
2424
2425 if (is_bitmap_slice_committed(r, true)) {
2426 // Some other region from the group is still committed, meaning the bitmap
2427 // slice is should stay committed, exit right away.
2428 return true;
2429 }
2430
2431 // Uncommit the bitmap slice:
2432 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2433 size_t off = _bitmap_bytes_per_slice * slice;
2434 size_t len = _bitmap_bytes_per_slice;
2435 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2436 return false;
2437 }
2438 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2439 return false;
2440 }
2441 return true;
2442 }
2443
2444 bool ShenandoahHeap::idle_bitmap_slice(ShenandoahHeapRegion *r) {
2445 assert_heaplock_owned_by_current_thread();
2446 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2447
2448 if (is_bitmap_slice_committed(r, true)) {
2449 // Some other region from the group is still committed, meaning the bitmap
2450 // slice is should stay committed, exit right away.
2451 return true;
2452 }
2453
2454 // Idle the bitmap slice:
2455 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2456 size_t off = _bitmap_bytes_per_slice * slice;
2457 size_t len = _bitmap_bytes_per_slice;
2458 if (!os::idle_memory((char*)_bitmap0_region.start() + off, len)) {
2459 return false;
2460 }
2461 if (!os::idle_memory((char*)_bitmap1_region.start() + off, len)) {
2462 return false;
2463 }
2464 return true;
2465 }
2466
2467 void ShenandoahHeap::activate_bitmap_slice(ShenandoahHeapRegion* r) {
2468 assert_heaplock_owned_by_current_thread();
2469 assert(ShenandoahUncommitWithIdle, "Must be enabled");
2470 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2471 size_t off = _bitmap_bytes_per_slice * slice;
2472 size_t len = _bitmap_bytes_per_slice;
2473 os::activate_memory((char*)_bitmap0_region.start() + off, len);
2474 os::activate_memory((char*)_bitmap1_region.start() + off, len);
2475 }
2476
2477 void ShenandoahHeap::safepoint_synchronize_begin() {
2478 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2479 SuspendibleThreadSet::synchronize();
2480 }
2481 }
2482
2483 void ShenandoahHeap::safepoint_synchronize_end() {
2484 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2485 SuspendibleThreadSet::desynchronize();
2486 }
2487 }
2488
2489 void ShenandoahHeap::vmop_entry_init_mark() {
2490 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2491 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2492 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2493
2494 try_inject_alloc_failure();
2495 VM_ShenandoahInitMark op;
2496 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2497 }
2498
2499 void ShenandoahHeap::vmop_entry_final_mark() {
2500 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2501 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2502 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2503
2504 try_inject_alloc_failure();
2505 VM_ShenandoahFinalMarkStartEvac op;
2506 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2507 }
2508
2509 void ShenandoahHeap::vmop_entry_final_evac() {
2510 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2511 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2512 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2513
2514 VM_ShenandoahFinalEvac op;
2515 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2516 }
2517
2518 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2519 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2520 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2521 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2522
2523 try_inject_alloc_failure();
2524 VM_ShenandoahInitUpdateRefs op;
2525 VMThread::execute(&op);
2526 }
2527
2528 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2529 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2530 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2531 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2532
2533 try_inject_alloc_failure();
2534 VM_ShenandoahFinalUpdateRefs op;
2535 VMThread::execute(&op);
2536 }
2537
2538 void ShenandoahHeap::vmop_entry_init_traversal() {
2539 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2540 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2541 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2542
2543 try_inject_alloc_failure();
2544 VM_ShenandoahInitTraversalGC op;
2545 VMThread::execute(&op);
2546 }
2547
2548 void ShenandoahHeap::vmop_entry_final_traversal() {
2549 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2550 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2551 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2552
2553 try_inject_alloc_failure();
2554 VM_ShenandoahFinalTraversalGC op;
2555 VMThread::execute(&op);
2556 }
2557
2558 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2559 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2560 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2561 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2562
2563 try_inject_alloc_failure();
2564 VM_ShenandoahFullGC op(cause);
2565 VMThread::execute(&op);
2566 }
2567
2568 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2569 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2570 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2571 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2572
2573 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2574 VMThread::execute(°enerated_gc);
2575 }
2576
2577 void ShenandoahHeap::entry_init_mark() {
2578 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2579 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2580
2581 FormatBuffer<> msg("Pause Init Mark%s%s%s",
2582 has_forwarded_objects() ? " (update refs)" : "",
2583 process_references() ? " (process refs)" : "",
2584 unload_classes() ? " (unload classes)" : "");
2585 GCTraceTime(Info, gc) time(msg, gc_timer());
2586 EventMark em("%s", msg.buffer());
2587
2588 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_init_marking());
2589
2590 op_init_mark();
2591 }
2592
2593 void ShenandoahHeap::entry_final_mark() {
2594 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2595 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2596
2597 FormatBuffer<> msg("Pause Final Mark%s%s%s",
2598 has_forwarded_objects() ? " (update refs)" : "",
2599 process_references() ? " (process refs)" : "",
2600 unload_classes() ? " (unload classes)" : "");
2601 GCTraceTime(Info, gc) time(msg, gc_timer());
2602 EventMark em("%s", msg.buffer());
2603
2604 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_marking());
2605
2606 op_final_mark();
2607 }
2608
2609 void ShenandoahHeap::entry_final_evac() {
2610 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2611 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2612
2613 FormatBuffer<> msg("Pause Final Evac");
2614 GCTraceTime(Info, gc) time(msg, gc_timer());
2615 EventMark em("%s", msg.buffer());
2616
2617 op_final_evac();
2618 }
2619
2620 void ShenandoahHeap::entry_init_updaterefs() {
2621 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2622 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2623
2624 static const char* msg = "Pause Init Update Refs";
2625 GCTraceTime(Info, gc) time(msg, gc_timer());
2626 EventMark em("%s", msg);
2627
2628 // No workers used in this phase, no setup required
2629
2630 op_init_updaterefs();
2631 }
2632
2633 void ShenandoahHeap::entry_final_updaterefs() {
2634 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2635 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2636
2637 static const char* msg = "Pause Final Update Refs";
2638 GCTraceTime(Info, gc) time(msg, gc_timer());
2639 EventMark em("%s", msg);
2640
2641 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_final_update_ref());
2642
2643 op_final_updaterefs();
2644 }
2645
2646 void ShenandoahHeap::entry_init_traversal() {
2647 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2648 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2649
2650 static const char* msg = "Pause Init Traversal";
2651 GCTraceTime(Info, gc) time(msg, gc_timer());
2652 EventMark em("%s", msg);
2653
2654 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2655
2656 op_init_traversal();
2657 }
2658
2659 void ShenandoahHeap::entry_final_traversal() {
2660 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2661 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2662
2663 static const char* msg = "Pause Final Traversal";
2664 GCTraceTime(Info, gc) time(msg, gc_timer());
2665 EventMark em("%s", msg);
2666
2667 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_traversal());
2668
2669 op_final_traversal();
2670 }
2671
2672 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2673 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2674 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2675
2676 static const char* msg = "Pause Full";
2677 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2678 EventMark em("%s", msg);
2679
2680 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_fullgc());
2681
2682 op_full(cause);
2683 }
2684
2685 void ShenandoahHeap::entry_degenerated(int point) {
2686 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2687 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2688
2689 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2690 FormatBuffer<> msg("Pause Degenerated GC (%s)", degen_point_to_string(dpoint));
2691 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2692 EventMark em("%s", msg.buffer());
2693
2694 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated());
2695
2696 set_degenerated_gc_in_progress(true);
2697 op_degenerated(dpoint);
2698 set_degenerated_gc_in_progress(false);
2699 }
2700
2701 void ShenandoahHeap::entry_mark() {
2702 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2703
2704 FormatBuffer<> msg("Concurrent marking%s%s%s",
2705 has_forwarded_objects() ? " (update refs)" : "",
2706 process_references() ? " (process refs)" : "",
2707 unload_classes() ? " (unload classes)" : "");
2708 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2709 EventMark em("%s", msg.buffer());
2710
2711 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_marking());
2712
2713 try_inject_alloc_failure();
2714 op_mark();
2715 }
2716
2717 void ShenandoahHeap::entry_evac() {
2718 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2719 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2720
2721 static const char* msg = "Concurrent evacuation";
2722 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2723 EventMark em("%s", msg);
2724
2725 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_evac());
2726
2727 try_inject_alloc_failure();
2728 op_evac();
2729 }
2730
2731 void ShenandoahHeap::entry_updaterefs() {
2732 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2733
2734 static const char* msg = "Concurrent update references";
2735 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2736 EventMark em("%s", msg);
2737
2738 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref());
2739
2740 try_inject_alloc_failure();
2741 op_updaterefs();
2742 }
2743 void ShenandoahHeap::entry_cleanup() {
2744 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2745
2746 static const char* msg = "Concurrent cleanup";
2747 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2748 EventMark em("%s", msg);
2749
2750 // This phase does not use workers, no need for setup
2751
2752 try_inject_alloc_failure();
2753 op_cleanup();
2754 }
2755
2756 void ShenandoahHeap::entry_cleanup_traversal() {
2757 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2758
2759 static const char* msg = "Concurrent cleanup";
2760 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2761 EventMark em("%s", msg);
2762
2763 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2764
2765 try_inject_alloc_failure();
2766 op_cleanup_traversal();
2767 }
2768
2769 void ShenandoahHeap::entry_cleanup_bitmaps() {
2770 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2771
2772 static const char* msg = "Concurrent cleanup";
2773 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2774 EventMark em("%s", msg);
2775
2776 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_cleanup());
2777
2778 try_inject_alloc_failure();
2779 op_cleanup_bitmaps();
2780 }
2781
2782 void ShenandoahHeap::entry_preclean() {
2783 if (ShenandoahPreclean && process_references()) {
2784 static const char* msg = "Concurrent precleaning";
2785 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2786 EventMark em("%s", msg);
2787
2788 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2789
2790 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_preclean());
2791
2792 try_inject_alloc_failure();
2793 op_preclean();
2794 }
2795 }
2796
2797 void ShenandoahHeap::entry_traversal() {
2798 static const char* msg = "Concurrent traversal";
2799 GCTraceTime(Info, gc) time(msg, gc_timer(), GCCause::_no_gc, true);
2800 EventMark em("%s", msg);
2801
2802 TraceCollectorStats tcs(is_minor_gc() ? monitoring_support()->partial_collection_counters()
2803 : monitoring_support()->concurrent_collection_counters());
2804
2805 ShenandoahWorkerScope scope(workers(), ShenandoahWorkerPolicy::calc_workers_for_conc_traversal());
2806
2807 try_inject_alloc_failure();
2808 op_traversal();
2809 }
2810
2811 void ShenandoahHeap::try_inject_alloc_failure() {
2812 if (ShenandoahAllocFailureALot && !cancelled_concgc() && ((os::random() % 1000) > 950)) {
2813 _inject_alloc_failure.set();
2814 os::naked_short_sleep(1);
2815 if (cancelled_concgc()) {
2816 log_info(gc)("Allocation failure was successfully injected");
2817 }
2818 }
2819 }
2820
2821 bool ShenandoahHeap::should_inject_alloc_failure() {
2822 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2823 }
2824
2825 void ShenandoahHeap::initialize_serviceability() {
2826 _memory_pool = new ShenandoahMemoryPool(this);
2827 _cycle_memory_manager.add_pool(_memory_pool);
2828 _stw_memory_manager.add_pool(_memory_pool);
2829 }
2830
2831 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2832 GrowableArray<GCMemoryManager*> memory_managers(2);
2833 memory_managers.append(&_cycle_memory_manager);
2834 memory_managers.append(&_stw_memory_manager);
2835 return memory_managers;
2836 }
2837
2838 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2839 GrowableArray<MemoryPool*> memory_pools(1);
2840 memory_pools.append(_memory_pool);
2841 return memory_pools;
2842 }
2843
2844 void ShenandoahHeap::enter_evacuation() {
2845 _oom_evac_handler.enter_evacuation();
2846 }
2847
2848 void ShenandoahHeap::leave_evacuation() {
2849 _oom_evac_handler.leave_evacuation();
2850 }
2851
2852 SoftRefPolicy* ShenandoahHeap::soft_ref_policy() {
2853 return &_soft_ref_policy;
2854 }
2855
2856 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2857 _index(0),
2858 _heap(ShenandoahHeap::heap()) {}
2859
2860 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2861 _index(0),
2862 _heap(heap) {}
2863
2864 ShenandoahRegionIterator& ShenandoahRegionIterator::operator=(const ShenandoahRegionIterator& o) {
2865 _index = o._index;
2866 assert(_heap == o._heap, "must be same");
2867 return *this;
2868 }
2869
2870 bool ShenandoahRegionIterator::has_next() const {
2871 return _index < _heap->num_regions();
2872 }
2873
2874 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure& cl) const {
2875 ShenandoahRegionIterator regions;
2876 ShenandoahHeapRegion* r = regions.next();
2877 while (r != NULL) {
2878 if (cl.heap_region_do(r)) {
2879 break;
2880 }
2881 r = regions.next();
2882 }
2883 }
2884
2885 bool ShenandoahHeap::is_minor_gc() const {
2886 return _gc_cycle_mode.get() == MINOR;
2887 }
2888
2889 bool ShenandoahHeap::is_major_gc() const {
2890 return _gc_cycle_mode.get() == MAJOR;
2891 }
2892
2893 void ShenandoahHeap::set_cycle_mode(GCCycleMode gc_cycle_mode) {
2894 _gc_cycle_mode.set(gc_cycle_mode);
2895 }
2896
2897 char ShenandoahHeap::gc_state() const {
2898 return _gc_state.raw_value();
2899 }