1 /*
2 * Copyright (c) 2013, 2017, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26
27 #include "gc/shared/gcTimer.hpp"
28 #include "gc/shared/gcTraceTime.inline.hpp"
29 #include "gc/shared/parallelCleaning.hpp"
30
31 #include "gc/shenandoah/brooksPointer.hpp"
32 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
33 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
34 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
35 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
36 #include "gc/shenandoah/shenandoahConcurrentMark.hpp"
37 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
38 #include "gc/shenandoah/shenandoahConcurrentThread.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/shenandoahMonitoringSupport.hpp"
46 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
47 #include "gc/shenandoah/shenandoahPartialGC.hpp"
48 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
49 #include "gc/shenandoah/shenandoahStringDedup.hpp"
50 #include "gc/shenandoah/shenandoahUtils.hpp"
51 #include "gc/shenandoah/shenandoahVerifier.hpp"
52 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
53 #include "gc/shenandoah/vm_operations_shenandoah.hpp"
54
55 #include "runtime/vmThread.hpp"
56 #include "services/mallocTracker.hpp"
57
58 ShenandoahUpdateRefsClosure::ShenandoahUpdateRefsClosure() : _heap(ShenandoahHeap::heap()) {}
59
60 #ifdef ASSERT
61 template <class T>
62 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) {
63 T o = oopDesc::load_heap_oop(p);
64 if (! oopDesc::is_null(o)) {
65 oop obj = oopDesc::decode_heap_oop_not_null(o);
66 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)),
67 "need to-space object here obj: "PTR_FORMAT" , rb(obj): "PTR_FORMAT", p: "PTR_FORMAT,
68 p2i(obj), p2i(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), p2i(p));
69 }
70 }
71
72 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
73 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
74 #endif
75
76 const char* ShenandoahHeap::name() const {
77 return "Shenandoah";
78 }
79
80 class ShenandoahPretouchTask : public AbstractGangTask {
81 private:
82 ShenandoahHeapRegionSet* _regions;
83 const size_t _bitmap_size;
84 const size_t _page_size;
85 char* _bitmap0_base;
86 char* _bitmap1_base;
87 public:
88 ShenandoahPretouchTask(ShenandoahHeapRegionSet* regions,
89 char* bitmap0_base, char* bitmap1_base, size_t bitmap_size,
90 size_t page_size) :
91 AbstractGangTask("Shenandoah PreTouch",
92 Universe::is_fully_initialized() ? GCId::current_raw() :
93 // During VM initialization there is
94 // no GC cycle that this task can be
95 // associated with.
96 GCId::undefined()),
97 _bitmap0_base(bitmap0_base),
98 _bitmap1_base(bitmap1_base),
99 _regions(regions),
100 _bitmap_size(bitmap_size),
101 _page_size(page_size) {
102 _regions->clear_current_index();
103 };
104
105 virtual void work(uint worker_id) {
106 ShenandoahHeapRegion* r = _regions->claim_next();
107 while (r != NULL) {
108 log_trace(gc, heap)("Pretouch region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
109 r->region_number(), p2i(r->bottom()), p2i(r->end()));
110 os::pretouch_memory(r->bottom(), r->end(), _page_size);
111
112 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
113 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
114 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
115
116 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
117 r->region_number(), p2i(_bitmap0_base + start), p2i(_bitmap0_base + end));
118 os::pretouch_memory(_bitmap0_base + start, _bitmap0_base + end, _page_size);
119
120 log_trace(gc, heap)("Pretouch bitmap under region " SIZE_FORMAT ": " PTR_FORMAT " -> " PTR_FORMAT,
121 r->region_number(), p2i(_bitmap1_base + start), p2i(_bitmap1_base + end));
122 os::pretouch_memory(_bitmap1_base + start, _bitmap1_base + end, _page_size);
123
124 r = _regions->claim_next();
125 }
126 }
127 };
128
129 jint ShenandoahHeap::initialize() {
130 CollectedHeap::pre_initialize();
131
132 BrooksPointer::initial_checks();
133
134 size_t init_byte_size = collector_policy()->initial_heap_byte_size();
135 size_t max_byte_size = collector_policy()->max_heap_byte_size();
136 size_t heap_alignment = collector_policy()->heap_alignment();
137
138 if (ShenandoahAlwaysPreTouch) {
139 // Enabled pre-touch means the entire heap is committed right away.
140 init_byte_size = max_byte_size;
141 }
142
143 Universe::check_alignment(max_byte_size,
144 ShenandoahHeapRegion::region_size_bytes(),
145 "shenandoah heap");
146 Universe::check_alignment(init_byte_size,
147 ShenandoahHeapRegion::region_size_bytes(),
148 "shenandoah heap");
149
150 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
151 heap_alignment);
152 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
153
154 set_barrier_set(new ShenandoahBarrierSet(this));
155 ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
156
157 _num_regions = max_byte_size / ShenandoahHeapRegion::region_size_bytes();
158 size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
159 _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
160 _committed = _initial_size;
161
162 log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT " bytes", init_byte_size);
163 if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
164 vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
165 }
166
167 size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
168 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
169
170 _ordered_regions = new ShenandoahHeapRegionSet(_num_regions);
171 _free_regions = new ShenandoahFreeSet(_ordered_regions, _num_regions);
172
173 _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
174
175 _next_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
176 _next_top_at_mark_starts = _next_top_at_mark_starts_base -
177 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
178
179 _complete_top_at_mark_starts_base = NEW_C_HEAP_ARRAY(HeapWord*, _num_regions, mtGC);
180 _complete_top_at_mark_starts = _complete_top_at_mark_starts_base -
181 ((uintx) pgc_rs.base() >> ShenandoahHeapRegion::region_size_bytes_shift());
182
183 {
184 ShenandoahHeapLocker locker(lock());
185 for (size_t i = 0; i < _num_regions; i++) {
186 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
187 (HeapWord*) pgc_rs.base() + reg_size_words * i,
188 reg_size_words,
189 i,
190 i < num_committed_regions);
191
192 _complete_top_at_mark_starts_base[i] = r->bottom();
193 _next_top_at_mark_starts_base[i] = r->bottom();
194
195 // Add to ordered regions first.
196 // We use the active size of ordered regions as the number of active regions in heap,
197 // free set and collection set use the number to assert the correctness of incoming regions.
198 _ordered_regions->add_region(r);
199 _free_regions->add_region(r);
200 assert(!collection_set()->is_in(i), "New region should not be in collection set");
201 }
202 }
203
204 assert(_ordered_regions->active_regions() == _num_regions, "Must match");
205 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
206 "misaligned heap: "PTR_FORMAT, p2i(base()));
207
208 LogTarget(Trace, gc, region) lt;
209 if (lt.is_enabled()) {
210 ResourceMark rm;
211 LogStream ls(lt);
212 log_trace(gc, region)("All Regions");
213 _ordered_regions->print_on(&ls);
214 log_trace(gc, region)("Free Regions");
215 _free_regions->print_on(&ls);
216 }
217
218 // The call below uses stuff (the SATB* things) that are in G1, but probably
219 // belong into a shared location.
220 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
221 SATB_Q_FL_lock,
222 20 /*G1SATBProcessCompletedThreshold */,
223 Shared_SATB_Q_lock);
224
225 // Reserve space for prev and next bitmap.
226 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
227 _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
228
229 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
230
231 guarantee(bitmap_bytes_per_region != 0,
232 "Bitmap bytes per region should not be zero");
233 guarantee(is_power_of_2(bitmap_bytes_per_region),
234 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
235
236 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
237
238 if (bitmap_page_size > bitmap_bytes_per_region) {
239 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
240 _bitmap_bytes_per_slice = bitmap_page_size;
241 } else {
242 _bitmap_regions_per_slice = 1;
243 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
244 }
245
246 guarantee(_bitmap_regions_per_slice >= 1,
247 "Should have at least one region per slice: " SIZE_FORMAT,
248 _bitmap_regions_per_slice);
249
250 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
251 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
252 _bitmap_bytes_per_slice, bitmap_page_size);
253
254 ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
255 MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
256 _bitmap0_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
257
258 ReservedSpace bitmap1(_bitmap_size, bitmap_page_size);
259 MemTracker::record_virtual_memory_type(bitmap1.base(), mtGC);
260 _bitmap1_region = MemRegion((HeapWord*) bitmap1.base(), bitmap1.size() / HeapWordSize);
261
262 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
263 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
264 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
265 os::commit_memory_or_exit((char *) (_bitmap0_region.start()), bitmap_init_commit, false,
266 "couldn't allocate initial bitmap");
267 os::commit_memory_or_exit((char *) (_bitmap1_region.start()), bitmap_init_commit, false,
268 "couldn't allocate initial bitmap");
269
270 size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
271
272 if (ShenandoahVerify) {
273 ReservedSpace verify_bitmap(_bitmap_size, page_size);
274 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
275 "couldn't allocate verification bitmap");
276 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
277 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
278 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
279 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
280 }
281
282 if (ShenandoahAlwaysPreTouch) {
283 assert (!AlwaysPreTouch, "Should have been overridden");
284
285 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
286 // before initialize() below zeroes it with initializing thread. For any given region,
287 // we touch the region and the corresponding bitmaps from the same thread.
288
289 log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
290 _ordered_regions->count(), page_size);
291 ShenandoahPretouchTask cl(_ordered_regions, bitmap0.base(), bitmap1.base(), _bitmap_size, page_size);
292 _workers->run_task(&cl);
293 }
294
295 _mark_bit_map0.initialize(_heap_region, _bitmap0_region);
296 _complete_mark_bit_map = &_mark_bit_map0;
297
298 _mark_bit_map1.initialize(_heap_region, _bitmap1_region);
299 _next_mark_bit_map = &_mark_bit_map1;
300
301 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
302 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
303 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
304 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
305 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
306
307 if (UseShenandoahMatrix) {
308 _connection_matrix = new ShenandoahConnectionMatrix(_num_regions);
309 } else {
310 _connection_matrix = NULL;
311 }
312
313 _partial_gc = _shenandoah_policy->can_do_partial_gc() ?
314 new ShenandoahPartialGC(this, _num_regions) :
315 NULL;
316
317 _monitoring_support = new ShenandoahMonitoringSupport(this);
318
319 _phase_timings = new ShenandoahPhaseTimings();
320
321 if (ShenandoahAllocationTrace) {
322 _alloc_tracker = new ShenandoahAllocTracker();
323 }
324
325 ShenandoahStringDedup::initialize();
326
327 _concurrent_gc_thread = new ShenandoahConcurrentThread();
328
329 ShenandoahMarkCompact::initialize();
330
331 ShenandoahCodeRoots::initialize();
332
333 return JNI_OK;
334 }
335
336 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
337 CollectedHeap(),
338 _shenandoah_policy(policy),
339 _concurrent_mark_in_progress(0),
340 _evacuation_in_progress(0),
341 _full_gc_in_progress(false),
342 _update_refs_in_progress(false),
343 _concurrent_partial_in_progress(false),
344 _free_regions(NULL),
345 _collection_set(NULL),
346 _bytes_allocated_since_cm(0),
347 _bytes_allocated_during_cm(0),
348 _allocated_last_gc(0),
349 _used_start_gc(0),
350 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
351 _ref_processor(NULL),
352 _next_top_at_mark_starts(NULL),
353 _next_top_at_mark_starts_base(NULL),
354 _complete_top_at_mark_starts(NULL),
355 _complete_top_at_mark_starts_base(NULL),
356 _mark_bit_map0(),
357 _mark_bit_map1(),
358 _aux_bit_map(),
359 _connection_matrix(NULL),
360 _cancelled_concgc(0),
361 _need_update_refs(false),
362 _need_reset_bitmaps(false),
363 _verifier(NULL),
364 _heap_lock(0),
365 _used_at_last_gc(0),
366 _alloc_seq_at_last_gc_start(0),
367 _alloc_seq_at_last_gc_end(0),
368 _safepoint_workers(NULL),
369 #ifdef ASSERT
370 _heap_lock_owner(NULL),
371 _heap_expansion_count(0),
372 #endif
373 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
374 _phase_timings(NULL),
375 _alloc_tracker(NULL)
376 {
377 log_info(gc, init)("Parallel GC threads: "UINT32_FORMAT, ParallelGCThreads);
378 log_info(gc, init)("Concurrent GC threads: "UINT32_FORMAT, ConcGCThreads);
379 log_info(gc, init)("Parallel reference processing enabled: %s", BOOL_TO_STR(ParallelRefProcEnabled));
380
381 _scm = new ShenandoahConcurrentMark();
382 _used = 0;
383
384 _max_workers = MAX2(_max_workers, 1U);
385 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
386 /* are_GC_task_threads */true,
387 /* are_ConcurrentGC_threads */false);
388 if (_workers == NULL) {
389 vm_exit_during_initialization("Failed necessary allocation.");
390 } else {
391 _workers->initialize_workers();
392 }
393
394 if (ParallelSafepointCleanupThreads > 1) {
395 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
396 ParallelSafepointCleanupThreads,
397 false, false);
398 _safepoint_workers->initialize_workers();
399 }
400 }
401
402 class ShenandoahResetNextBitmapTask : public AbstractGangTask {
403 private:
404 ShenandoahHeapRegionSet* _regions;
405
406 public:
407 ShenandoahResetNextBitmapTask(ShenandoahHeapRegionSet* regions) :
408 AbstractGangTask("Parallel Reset Bitmap Task"),
409 _regions(regions) {
410 _regions->clear_current_index();
411 }
412
413 void work(uint worker_id) {
414 ShenandoahHeapRegion* region = _regions->claim_next();
415 ShenandoahHeap* heap = ShenandoahHeap::heap();
416 while (region != NULL) {
417 if (heap->is_bitmap_slice_committed(region)) {
418 HeapWord* bottom = region->bottom();
419 HeapWord* top = heap->next_top_at_mark_start(region->bottom());
420 if (top > bottom) {
421 heap->next_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
422 }
423 assert(heap->is_next_bitmap_clear_range(bottom, region->end()), "must be clear");
424 }
425 region = _regions->claim_next();
426 }
427 }
428 };
429
430 void ShenandoahHeap::reset_next_mark_bitmap(WorkGang* workers) {
431 assert_gc_workers(workers->active_workers());
432
433 ShenandoahResetNextBitmapTask task = ShenandoahResetNextBitmapTask(_ordered_regions);
434 workers->run_task(&task);
435 }
436
437 class ShenandoahResetCompleteBitmapTask : public AbstractGangTask {
438 private:
439 ShenandoahHeapRegionSet* _regions;
440
441 public:
442 ShenandoahResetCompleteBitmapTask(ShenandoahHeapRegionSet* regions) :
443 AbstractGangTask("Parallel Reset Bitmap Task"),
444 _regions(regions) {
445 _regions->clear_current_index();
446 }
447
448 void work(uint worker_id) {
449 ShenandoahHeapRegion* region = _regions->claim_next();
450 ShenandoahHeap* heap = ShenandoahHeap::heap();
451 while (region != NULL) {
452 if (heap->is_bitmap_slice_committed(region)) {
453 HeapWord* bottom = region->bottom();
454 HeapWord* top = heap->complete_top_at_mark_start(region->bottom());
455 if (top > bottom) {
456 heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
457 }
458 assert(heap->is_complete_bitmap_clear_range(bottom, region->end()), "must be clear");
459 }
460 region = _regions->claim_next();
461 }
462 }
463 };
464
465 void ShenandoahHeap::reset_complete_mark_bitmap(WorkGang* workers) {
466 assert_gc_workers(workers->active_workers());
467
468 ShenandoahResetCompleteBitmapTask task = ShenandoahResetCompleteBitmapTask(_ordered_regions);
469 workers->run_task(&task);
470 }
471
472 bool ShenandoahHeap::is_next_bitmap_clear() {
473 for (size_t idx = 0; idx < _num_regions; idx++) {
474 ShenandoahHeapRegion* r = _ordered_regions->get(idx);
475 if (is_bitmap_slice_committed(r) && !is_next_bitmap_clear_range(r->bottom(), r->end())) {
476 return false;
477 }
478 }
479 return true;
480 }
481
482 bool ShenandoahHeap::is_next_bitmap_clear_range(HeapWord* start, HeapWord* end) {
483 return _next_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
484 }
485
486 bool ShenandoahHeap::is_complete_bitmap_clear_range(HeapWord* start, HeapWord* end) {
487 return _complete_mark_bit_map->getNextMarkedWordAddress(start, end) == end;
488 }
489
490 void ShenandoahHeap::print_on(outputStream* st) const {
491 st->print_cr("Shenandoah Heap");
492 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
493 capacity() / K, committed() / K, used() / K);
494 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
495 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
496
497 st->print("Status: ");
498 if (concurrent_mark_in_progress()) {
499 st->print("marking ");
500 } else if (is_evacuation_in_progress()) {
501 st->print("evacuating ");
502 } else if (is_update_refs_in_progress()) {
503 st->print("updating refs ");
504 } else {
505 st->print("idle ");
506 }
507 if (cancelled_concgc()) {
508 st->print("cancelled ");
509 }
510 st->cr();
511
512 st->print_cr("Reserved region:");
513 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
514 p2i(reserved_region().start()),
515 p2i(reserved_region().end()));
516
517 if (UseShenandoahMatrix) {
518 st->print_cr("Matrix:");
519
520 ShenandoahConnectionMatrix* matrix = connection_matrix();
521 if (matrix != NULL) {
522 st->print_cr(" - base: " PTR_FORMAT, p2i(matrix->matrix_addr()));
523 st->print_cr(" - stride: " SIZE_FORMAT, matrix->stride());
524 st->print_cr(" - magic: " PTR_FORMAT, matrix->magic_offset());
525 } else {
526 st->print_cr(" No matrix.");
527 }
528 }
529
530 if (Verbose) {
531 print_heap_regions_on(st);
532 }
533 }
534
535 class ShenandoahInitGCLABClosure : public ThreadClosure {
536 public:
537 void do_thread(Thread* thread) {
538 thread->gclab().initialize(true);
539 }
540 };
541
542 void ShenandoahHeap::post_initialize() {
543 if (UseTLAB) {
544 MutexLocker ml(Threads_lock);
545
546 ShenandoahInitGCLABClosure init_gclabs;
547 Threads::java_threads_do(&init_gclabs);
548 gc_threads_do(&init_gclabs);
549
550 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
551 // Now, we will let WorkGang to initialize gclab when new worker is created.
552 _workers->set_initialize_gclab();
553 }
554
555 _scm->initialize(_max_workers);
556
557 ref_processing_init();
558
559 _shenandoah_policy->post_heap_initialize();
560 }
561
562 size_t ShenandoahHeap::used() const {
563 OrderAccess::acquire();
564 return _used;
565 }
566
567 size_t ShenandoahHeap::committed() const {
568 OrderAccess::acquire();
569 return _committed;
570 }
571
572 void ShenandoahHeap::increase_committed(size_t bytes) {
573 assert_heaplock_or_safepoint();
574 _committed += bytes;
575 }
576
577 void ShenandoahHeap::decrease_committed(size_t bytes) {
578 assert_heaplock_or_safepoint();
579 _committed -= bytes;
580 }
581
582 void ShenandoahHeap::increase_used(size_t bytes) {
583 assert_heaplock_or_safepoint();
584 _used += bytes;
585 }
586
587 void ShenandoahHeap::set_used(size_t bytes) {
588 assert_heaplock_or_safepoint();
589 _used = bytes;
590 }
591
592 void ShenandoahHeap::decrease_used(size_t bytes) {
593 assert_heaplock_or_safepoint();
594 assert(_used >= bytes, "never decrease heap size by more than we've left");
595 _used -= bytes;
596 }
597
598 size_t ShenandoahHeap::capacity() const {
599 return num_regions() * ShenandoahHeapRegion::region_size_bytes();
600 }
601
602 bool ShenandoahHeap::is_maximal_no_gc() const {
603 Unimplemented();
604 return true;
605 }
606
607 size_t ShenandoahHeap::max_capacity() const {
608 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
609 }
610
611 size_t ShenandoahHeap::initial_capacity() const {
612 return _initial_size;
613 }
614
615 bool ShenandoahHeap::is_in(const void* p) const {
616 HeapWord* heap_base = (HeapWord*) base();
617 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
618 return p >= heap_base && p < last_region_end;
619 }
620
621 bool ShenandoahHeap::is_scavengable(const void* p) {
622 return true;
623 }
624
625 void ShenandoahHeap::handle_heap_shrinkage() {
626 ShenandoahHeapLocker locker(lock());
627
628 ShenandoahHeapRegionSet* set = regions();
629
630 size_t count = 0;
631 double current = os::elapsedTime();
632 for (size_t i = 0; i < num_regions(); i++) {
633 ShenandoahHeapRegion* r = set->get(i);
634 if (r->is_empty_committed() &&
635 (current - r->empty_time()) * 1000 > ShenandoahUncommitDelay &&
636 r->make_empty_uncommitted()) {
637 count++;
638 }
639 }
640
641 if (count > 0) {
642 log_info(gc)("Uncommitted " SIZE_FORMAT "M. Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used",
643 count * ShenandoahHeapRegion::region_size_bytes() / M, capacity() / M, committed() / M, used() / M);
644 }
645 }
646
647 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
648 // Retain tlab and allocate object in shared space if
649 // the amount free in the tlab is too large to discard.
650 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) {
651 thread->gclab().record_slow_allocation(size);
652 return NULL;
653 }
654
655 // Discard gclab and allocate a new one.
656 // To minimize fragmentation, the last GCLAB may be smaller than the rest.
657 size_t new_gclab_size = thread->gclab().compute_size(size);
658
659 thread->gclab().clear_before_allocation();
660
661 if (new_gclab_size == 0) {
662 return NULL;
663 }
664
665 // Allocate a new GCLAB...
666 HeapWord* obj = allocate_new_gclab(new_gclab_size);
667 if (obj == NULL) {
668 return NULL;
669 }
670
671 if (ZeroTLAB) {
672 // ..and clear it.
673 Copy::zero_to_words(obj, new_gclab_size);
674 } else {
675 // ...and zap just allocated object.
676 #ifdef ASSERT
677 // Skip mangling the space corresponding to the object header to
678 // ensure that the returned space is not considered parsable by
679 // any concurrent GC thread.
680 size_t hdr_size = oopDesc::header_size();
681 Copy::fill_to_words(obj + hdr_size, new_gclab_size - hdr_size, badHeapWordVal);
682 #endif // ASSERT
683 }
684 thread->gclab().fill(obj, obj + size, new_gclab_size);
685 return obj;
686 }
687
688 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) {
689 #ifdef ASSERT
690 log_debug(gc, alloc)("Allocate new tlab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
691 #endif
692 return allocate_new_lab(word_size, _alloc_tlab);
693 }
694
695 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t word_size) {
696 #ifdef ASSERT
697 log_debug(gc, alloc)("Allocate new gclab, requested size = " SIZE_FORMAT " bytes", word_size * HeapWordSize);
698 #endif
699 return allocate_new_lab(word_size, _alloc_gclab);
700 }
701
702 HeapWord* ShenandoahHeap::allocate_new_lab(size_t word_size, AllocType type) {
703 HeapWord* result = allocate_memory(word_size, type);
704
705 if (result != NULL) {
706 assert(! in_collection_set(result), "Never allocate in collection set");
707 _bytes_allocated_since_cm += word_size * HeapWordSize;
708
709 log_develop_trace(gc, tlab)("allocating new tlab of size "SIZE_FORMAT" at addr "PTR_FORMAT, word_size, p2i(result));
710
711 }
712 return result;
713 }
714
715 ShenandoahHeap* ShenandoahHeap::heap() {
716 CollectedHeap* heap = Universe::heap();
717 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
718 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap");
719 return (ShenandoahHeap*) heap;
720 }
721
722 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
723 CollectedHeap* heap = Universe::heap();
724 return (ShenandoahHeap*) heap;
725 }
726
727 HeapWord* ShenandoahHeap::allocate_memory(size_t word_size, AllocType type) {
728 ShenandoahAllocTrace trace_alloc(word_size, type);
729
730 bool in_new_region = false;
731 HeapWord* result = allocate_memory_under_lock(word_size, type, in_new_region);
732
733 if (type == _alloc_tlab || type == _alloc_shared) {
734 // Allocation failed, try full-GC, then retry allocation.
735 //
736 // It might happen that one of the threads requesting allocation would unblock
737 // way later after full-GC happened, only to fail the second allocation, because
738 // other threads have already depleted the free storage. In this case, a better
739 // strategy would be to try full-GC again.
740 //
741 // Lacking the way to detect progress from "collect" call, we are left with blindly
742 // retrying for some bounded number of times.
743 // TODO: Poll if Full GC made enough progress to warrant retry.
744 int tries = 0;
745 while ((result == NULL) && (tries++ < ShenandoahFullGCTries)) {
746 log_debug(gc)("[" PTR_FORMAT " Failed to allocate " SIZE_FORMAT " bytes, doing full GC, try %d",
747 p2i(Thread::current()), word_size * HeapWordSize, tries);
748 collect(GCCause::_allocation_failure);
749 result = allocate_memory_under_lock(word_size, type, in_new_region);
750 }
751 }
752
753 if (in_new_region) {
754 // Update monitoring counters when we took a new region. This amortizes the
755 // update costs on slow path.
756 concurrent_thread()->trigger_counters_update();
757 }
758
759 log_develop_trace(gc, alloc)("allocate memory chunk of size "SIZE_FORMAT" at addr "PTR_FORMAT " by thread %d ",
760 word_size, p2i(result), Thread::current()->osthread()->thread_id());
761
762 return result;
763 }
764
765 HeapWord* ShenandoahHeap::allocate_memory_under_lock(size_t word_size, AllocType type, bool& in_new_region) {
766 ShenandoahHeapLocker locker(lock());
767 return _free_regions->allocate(word_size, type, in_new_region);
768 }
769
770 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
771 bool* gc_overhead_limit_was_exceeded) {
772 HeapWord* filler = allocate_memory(size + BrooksPointer::word_size(), _alloc_shared);
773 HeapWord* result = filler + BrooksPointer::word_size();
774 if (filler != NULL) {
775 BrooksPointer::initialize(oop(result));
776 _bytes_allocated_since_cm += size * HeapWordSize;
777
778 assert(! in_collection_set(result), "never allocate in targetted region");
779 return result;
780 } else {
781 return NULL;
782 }
783 }
784
785 class ShenandoahEvacuateUpdateRootsClosure: public ExtendedOopClosure {
786 private:
787 ShenandoahHeap* _heap;
788 Thread* _thread;
789 public:
790 ShenandoahEvacuateUpdateRootsClosure() :
791 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
792 }
793
794 private:
795 template <class T>
796 void do_oop_work(T* p) {
797 assert(_heap->is_evacuation_in_progress(), "Only do this when evacuation is in progress");
798
799 T o = oopDesc::load_heap_oop(p);
800 if (! oopDesc::is_null(o)) {
801 oop obj = oopDesc::decode_heap_oop_not_null(o);
802 if (_heap->in_collection_set(obj)) {
803 assert(_heap->is_marked_complete(obj), "only evacuate marked objects %d %d",
804 _heap->is_marked_complete(obj), _heap->is_marked_complete(ShenandoahBarrierSet::resolve_oop_static_not_null(obj)));
805 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
806 if (oopDesc::unsafe_equals(resolved, obj)) {
807 bool evac;
808 resolved = _heap->evacuate_object(obj, _thread, evac);
809 }
810 oopDesc::encode_store_heap_oop(p, resolved);
811 }
812 }
813 }
814
815 public:
816 void do_oop(oop* p) {
817 do_oop_work(p);
818 }
819 void do_oop(narrowOop* p) {
820 do_oop_work(p);
821 }
822 };
823
824 class ShenandoahEvacuateRootsClosure: public ExtendedOopClosure {
825 private:
826 ShenandoahHeap* _heap;
827 Thread* _thread;
828 public:
829 ShenandoahEvacuateRootsClosure() :
830 _heap(ShenandoahHeap::heap()), _thread(Thread::current()) {
831 }
832
833 private:
834 template <class T>
835 void do_oop_work(T* p) {
836 T o = oopDesc::load_heap_oop(p);
837 if (! oopDesc::is_null(o)) {
838 oop obj = oopDesc::decode_heap_oop_not_null(o);
839 if (_heap->in_collection_set(obj)) {
840 oop resolved = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
841 if (oopDesc::unsafe_equals(resolved, obj)) {
842 bool evac;
843 _heap->evacuate_object(obj, _thread, evac);
844 }
845 }
846 }
847 }
848
849 public:
850 void do_oop(oop* p) {
851 do_oop_work(p);
852 }
853 void do_oop(narrowOop* p) {
854 do_oop_work(p);
855 }
856 };
857
858 class ShenandoahParallelEvacuateRegionObjectClosure : public ObjectClosure {
859 private:
860 ShenandoahHeap* const _heap;
861 Thread* const _thread;
862 public:
863 ShenandoahParallelEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
864 _heap(heap), _thread(Thread::current()) {}
865
866 void do_object(oop p) {
867 assert(_heap->is_marked_complete(p), "expect only marked objects");
868 if (oopDesc::unsafe_equals(p, ShenandoahBarrierSet::resolve_oop_static_not_null(p))) {
869 bool evac;
870 _heap->evacuate_object(p, _thread, evac);
871 }
872 }
873 };
874
875 class ShenandoahParallelEvacuationTask : public AbstractGangTask {
876 private:
877 ShenandoahHeap* const _sh;
878 ShenandoahCollectionSet* const _cs;
879 volatile jbyte _claimed_codecache;
880
881 bool claim_codecache() {
882 jbyte old = Atomic::cmpxchg((jbyte)1, &_claimed_codecache, (jbyte)0);
883 return old == 0;
884 }
885 public:
886 ShenandoahParallelEvacuationTask(ShenandoahHeap* sh,
887 ShenandoahCollectionSet* cs) :
888 AbstractGangTask("Parallel Evacuation Task"),
889 _cs(cs),
890 _sh(sh),
891 _claimed_codecache(0)
892 {}
893
894 void work(uint worker_id) {
895
896 SuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
897
898 // If concurrent code cache evac is enabled, evacuate it here.
899 // Note we cannot update the roots here, because we risk non-atomic stores to the alive
900 // nmethods. The update would be handled elsewhere.
901 if (ShenandoahConcurrentEvacCodeRoots && claim_codecache()) {
902 ShenandoahEvacuateRootsClosure cl;
903 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
904 CodeBlobToOopClosure blobs(&cl, !CodeBlobToOopClosure::FixRelocations);
905 CodeCache::blobs_do(&blobs);
906 }
907
908 ShenandoahParallelEvacuateRegionObjectClosure cl(_sh);
909 ShenandoahHeapRegion* r;
910 while ((r =_cs->claim_next()) != NULL) {
911 log_develop_trace(gc, region)("Thread "INT32_FORMAT" claimed Heap Region "SIZE_FORMAT,
912 worker_id,
913 r->region_number());
914
915 assert(r->has_live(), "all-garbage regions are reclaimed early");
916 _sh->marked_object_iterate(r, &cl);
917
918 if (_sh->check_cancelled_concgc_and_yield()) {
919 log_develop_trace(gc, region)("Cancelled concgc while evacuating region " SIZE_FORMAT, r->region_number());
920 break;
921 }
922 }
923 }
924 };
925
926 void ShenandoahHeap::trash_cset_regions() {
927 ShenandoahHeapLocker locker(lock());
928
929 ShenandoahCollectionSet* set = collection_set();
930 ShenandoahHeapRegion* r;
931 set->clear_current_index();
932 while ((r = set->next()) != NULL) {
933 r->make_trash();
934 }
935 collection_set()->clear();
936 }
937
938 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
939 st->print_cr("Heap Regions:");
940 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
941 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
942 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
943 st->print_cr("FTS=first use timestamp, LTS=last use timestamp");
944
945 _ordered_regions->print_on(st);
946 }
947
948 size_t ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
949 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
950
951 oop humongous_obj = oop(start->bottom() + BrooksPointer::word_size());
952 size_t size = humongous_obj->size() + BrooksPointer::word_size();
953 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
954 size_t index = start->region_number() + required_regions - 1;
955
956 assert(!start->has_live(), "liveness must be zero");
957 log_trace(gc, humongous)("Reclaiming "SIZE_FORMAT" humongous regions for object of size: "SIZE_FORMAT" words", required_regions, size);
958
959 for(size_t i = 0; i < required_regions; i++) {
960 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
961 // as it expects that every region belongs to a humongous region starting with a humongous start region.
962 ShenandoahHeapRegion* region = _ordered_regions->get(index --);
963
964 LogTarget(Trace, gc, humongous) lt;
965 if (lt.is_enabled()) {
966 ResourceMark rm;
967 LogStream ls(lt);
968 region->print_on(&ls);
969 }
970
971 assert(region->is_humongous(), "expect correct humongous start or continuation");
972 assert(!in_collection_set(region), "Humongous region should not be in collection set");
973
974 region->make_trash();
975 }
976 return required_regions;
977 }
978
979 #ifdef ASSERT
980 class ShenandoahCheckCollectionSetClosure: public ShenandoahHeapRegionClosure {
981 bool heap_region_do(ShenandoahHeapRegion* r) {
982 assert(! ShenandoahHeap::heap()->in_collection_set(r), "Should have been cleared by now");
983 return false;
984 }
985 };
986 #endif
987
988 void ShenandoahHeap::prepare_for_concurrent_evacuation() {
989 assert(_ordered_regions->get(0)->region_number() == 0, "FIXME CHF. FIXME CHF!");
990
991 log_develop_trace(gc)("Thread %d started prepare_for_concurrent_evacuation", Thread::current()->osthread()->thread_id());
992
993 if (!cancelled_concgc()) {
994 // Allocations might have happened before we STWed here, record peak:
995 shenandoahPolicy()->record_peak_occupancy();
996
997 make_tlabs_parsable(true);
998
999 if (ShenandoahVerify) {
1000 verifier()->verify_after_concmark();
1001 }
1002
1003 trash_cset_regions();
1004
1005 // NOTE: This needs to be done during a stop the world pause, because
1006 // putting regions into the collection set concurrently with Java threads
1007 // will create a race. In particular, acmp could fail because when we
1008 // resolve the first operand, the containing region might not yet be in
1009 // the collection set, and thus return the original oop. When the 2nd
1010 // operand gets resolved, the region could be in the collection set
1011 // and the oop gets evacuated. If both operands have originally been
1012 // the same, we get false negatives.
1013
1014 {
1015 ShenandoahHeapLocker locker(lock());
1016 _collection_set->clear();
1017 _free_regions->clear();
1018
1019 #ifdef ASSERT
1020 ShenandoahCheckCollectionSetClosure ccsc;
1021 _ordered_regions->heap_region_iterate(&ccsc);
1022 #endif
1023
1024 _shenandoah_policy->choose_collection_set(_collection_set);
1025
1026 _shenandoah_policy->choose_free_set(_free_regions);
1027 }
1028
1029 _bytes_allocated_since_cm = 0;
1030
1031 Universe::update_heap_info_at_gc();
1032
1033 if (ShenandoahVerify) {
1034 verifier()->verify_before_evacuation();
1035 }
1036 }
1037 }
1038
1039
1040 class ShenandoahRetireTLABClosure : public ThreadClosure {
1041 private:
1042 bool _retire;
1043
1044 public:
1045 ShenandoahRetireTLABClosure(bool retire) : _retire(retire) {}
1046
1047 void do_thread(Thread* thread) {
1048 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1049 thread->gclab().make_parsable(_retire);
1050 }
1051 };
1052
1053 void ShenandoahHeap::make_tlabs_parsable(bool retire_tlabs) {
1054 if (UseTLAB) {
1055 CollectedHeap::ensure_parsability(retire_tlabs);
1056 ShenandoahRetireTLABClosure cl(retire_tlabs);
1057 Threads::java_threads_do(&cl);
1058 gc_threads_do(&cl);
1059 }
1060 }
1061
1062
1063 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1064 ShenandoahRootEvacuator* _rp;
1065 public:
1066
1067 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1068 AbstractGangTask("Shenandoah evacuate and update roots"),
1069 _rp(rp)
1070 {
1071 // Nothing else to do.
1072 }
1073
1074 void work(uint worker_id) {
1075 ShenandoahEvacuateUpdateRootsClosure cl;
1076
1077 if (ShenandoahConcurrentEvacCodeRoots) {
1078 _rp->process_evacuate_roots(&cl, NULL, worker_id);
1079 } else {
1080 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1081 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1082 }
1083 }
1084 };
1085
1086 class ShenandoahFixRootsTask : public AbstractGangTask {
1087 ShenandoahRootEvacuator* _rp;
1088 public:
1089
1090 ShenandoahFixRootsTask(ShenandoahRootEvacuator* rp) :
1091 AbstractGangTask("Shenandoah update roots"),
1092 _rp(rp)
1093 {
1094 // Nothing else to do.
1095 }
1096
1097 void work(uint worker_id) {
1098 ShenandoahUpdateRefsClosure cl;
1099 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1100
1101 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1102 }
1103 };
1104
1105 void ShenandoahHeap::evacuate_and_update_roots() {
1106
1107 #if defined(COMPILER2) || INCLUDE_JVMCI
1108 DerivedPointerTable::clear();
1109 #endif
1110 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1111
1112 {
1113 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1114 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1115 workers()->run_task(&roots_task);
1116 }
1117
1118 #if defined(COMPILER2) || INCLUDE_JVMCI
1119 DerivedPointerTable::update_pointers();
1120 #endif
1121 if (cancelled_concgc()) {
1122 fixup_roots();
1123 }
1124 }
1125
1126
1127 void ShenandoahHeap::fixup_roots() {
1128 assert(cancelled_concgc(), "Only after concurrent cycle failed");
1129
1130 // If initial evacuation has been cancelled, we need to update all references
1131 // after all workers have finished. Otherwise we might run into the following problem:
1132 // GC thread 1 cannot allocate anymore, thus evacuation fails, leaves from-space ptr of object X.
1133 // GC thread 2 evacuates the same object X to to-space
1134 // which leaves a truly dangling from-space reference in the first root oop*. This must not happen.
1135 // clear() and update_pointers() must always be called in pairs,
1136 // cannot nest with above clear()/update_pointers().
1137 #if defined(COMPILER2) || INCLUDE_JVMCI
1138 DerivedPointerTable::clear();
1139 #endif
1140 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1141 ShenandoahFixRootsTask update_roots_task(&rp);
1142 workers()->run_task(&update_roots_task);
1143 #if defined(COMPILER2) || INCLUDE_JVMCI
1144 DerivedPointerTable::update_pointers();
1145 #endif
1146 }
1147
1148 void ShenandoahHeap::do_evacuation() {
1149 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
1150
1151 LogTarget(Trace, gc, region) lt_region;
1152 LogTarget(Trace, gc, cset) lt_cset;
1153
1154 if (lt_region.is_enabled()) {
1155 ResourceMark rm;
1156 LogStream ls(lt_region);
1157 ls.print_cr("All available regions:");
1158 print_heap_regions_on(&ls);
1159 }
1160
1161 if (lt_cset.is_enabled()) {
1162 ResourceMark rm;
1163 LogStream ls(lt_cset);
1164 ls.print_cr("Collection set ("SIZE_FORMAT" regions):", _collection_set->count());
1165 _collection_set->print_on(&ls);
1166
1167 ls.print_cr("Free set:");
1168 _free_regions->print_on(&ls);
1169 }
1170
1171 ShenandoahParallelEvacuationTask task(this, _collection_set);
1172 workers()->run_task(&task);
1173
1174 if (lt_cset.is_enabled()) {
1175 ResourceMark rm;
1176 LogStream ls(lt_cset);
1177 ls.print_cr("After evacuation collection set ("SIZE_FORMAT" regions):",
1178 _collection_set->count());
1179 _collection_set->print_on(&ls);
1180
1181 ls.print_cr("After evacuation free set:");
1182 _free_regions->print_on(&ls);
1183 }
1184
1185 if (lt_region.is_enabled()) {
1186 ResourceMark rm;
1187 LogStream ls(lt_region);
1188 ls.print_cr("All regions after evacuation:");
1189 print_heap_regions_on(&ls);
1190 }
1191 }
1192
1193 void ShenandoahHeap::roots_iterate(OopClosure* cl) {
1194 assert(SafepointSynchronize::is_at_safepoint(), "Only iterate roots while world is stopped");
1195
1196 CodeBlobToOopClosure blobsCl(cl, false);
1197 CLDToOopClosure cldCl(cl);
1198
1199 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1200 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, 0);
1201 }
1202
1203 bool ShenandoahHeap::supports_tlab_allocation() const {
1204 return true;
1205 }
1206
1207 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1208 return MIN2(_free_regions->unsafe_peek_free(), max_tlab_size());
1209 }
1210
1211 size_t ShenandoahHeap::max_tlab_size() const {
1212 return ShenandoahHeapRegion::max_tlab_size_bytes();
1213 }
1214
1215 class ShenandoahResizeGCLABClosure : public ThreadClosure {
1216 public:
1217 void do_thread(Thread* thread) {
1218 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1219 thread->gclab().resize();
1220 }
1221 };
1222
1223 void ShenandoahHeap::resize_all_tlabs() {
1224 CollectedHeap::resize_all_tlabs();
1225
1226 ShenandoahResizeGCLABClosure cl;
1227 Threads::java_threads_do(&cl);
1228 gc_threads_do(&cl);
1229 }
1230
1231 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure {
1232 public:
1233 void do_thread(Thread* thread) {
1234 assert(thread->gclab().is_initialized(), "GCLAB should be initialized for %s", thread->name());
1235 thread->gclab().accumulate_statistics();
1236 thread->gclab().initialize_statistics();
1237 }
1238 };
1239
1240 void ShenandoahHeap::accumulate_statistics_all_gclabs() {
1241 ShenandoahAccumulateStatisticsGCLABClosure cl;
1242 Threads::java_threads_do(&cl);
1243 gc_threads_do(&cl);
1244 }
1245
1246 bool ShenandoahHeap::can_elide_tlab_store_barriers() const {
1247 return true;
1248 }
1249
1250 oop ShenandoahHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
1251 // Overridden to do nothing.
1252 return new_obj;
1253 }
1254
1255 bool ShenandoahHeap::can_elide_initializing_store_barrier(oop new_obj) {
1256 return true;
1257 }
1258
1259 bool ShenandoahHeap::card_mark_must_follow_store() const {
1260 return false;
1261 }
1262
1263 void ShenandoahHeap::collect(GCCause::Cause cause) {
1264 assert(cause != GCCause::_gc_locker, "no JNI critical callback");
1265 if (GCCause::is_user_requested_gc(cause)) {
1266 if (!DisableExplicitGC) {
1267 if (ExplicitGCInvokesConcurrent) {
1268 _concurrent_gc_thread->do_conc_gc();
1269 } else {
1270 _concurrent_gc_thread->do_full_gc(cause);
1271 }
1272 }
1273 } else if (cause == GCCause::_allocation_failure) {
1274 collector_policy()->set_should_clear_all_soft_refs(true);
1275 _concurrent_gc_thread->do_full_gc(cause);
1276 }
1277 }
1278
1279 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1280 //assert(false, "Shouldn't need to do full collections");
1281 }
1282
1283 AdaptiveSizePolicy* ShenandoahHeap::size_policy() {
1284 Unimplemented();
1285 return NULL;
1286
1287 }
1288
1289 CollectorPolicy* ShenandoahHeap::collector_policy() const {
1290 return _shenandoah_policy;
1291 }
1292
1293
1294 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1295 Space* sp = heap_region_containing(addr);
1296 if (sp != NULL) {
1297 return sp->block_start(addr);
1298 }
1299 return NULL;
1300 }
1301
1302 size_t ShenandoahHeap::block_size(const HeapWord* addr) const {
1303 Space* sp = heap_region_containing(addr);
1304 assert(sp != NULL, "block_size of address outside of heap");
1305 return sp->block_size(addr);
1306 }
1307
1308 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1309 Space* sp = heap_region_containing(addr);
1310 return sp->block_is_obj(addr);
1311 }
1312
1313 jlong ShenandoahHeap::millis_since_last_gc() {
1314 return 0;
1315 }
1316
1317 void ShenandoahHeap::prepare_for_verify() {
1318 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1319 make_tlabs_parsable(false);
1320 }
1321 }
1322
1323 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1324 workers()->print_worker_threads_on(st);
1325 }
1326
1327 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1328 workers()->threads_do(tcl);
1329 }
1330
1331 void ShenandoahHeap::print_tracing_info() const {
1332 LogTarget(Info, gc, stats) lt;
1333 if (lt.is_enabled()) {
1334 ResourceMark rm;
1335 LogStream ls(lt);
1336
1337 phase_timings()->print_on(&ls);
1338
1339 ls.cr();
1340 ls.cr();
1341
1342 shenandoahPolicy()->print_gc_stats(&ls);
1343
1344 ls.cr();
1345 ls.cr();
1346
1347 if (ShenandoahAllocationTrace) {
1348 assert(alloc_tracker() != NULL, "Must be");
1349 alloc_tracker()->print_on(&ls);
1350 } else {
1351 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1352 }
1353 }
1354 }
1355
1356 void ShenandoahHeap::verify(VerifyOption vo) {
1357 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1358 if (ShenandoahVerify) {
1359 verifier()->verify_generic(vo);
1360 } else {
1361 // TODO: Consider allocating verification bitmaps on demand,
1362 // and turn this on unconditionally.
1363 }
1364 }
1365 }
1366 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1367 return _free_regions->capacity();
1368 }
1369
1370 class ObjectIterateScanRootClosure : public ExtendedOopClosure {
1371 private:
1372 MarkBitMap* _bitmap;
1373 Stack<oop,mtGC>* _oop_stack;
1374
1375 template <class T>
1376 void do_oop_work(T* p) {
1377 T o = oopDesc::load_heap_oop(p);
1378 if (!oopDesc::is_null(o)) {
1379 oop obj = oopDesc::decode_heap_oop_not_null(o);
1380 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1381 assert(oopDesc::is_oop(obj), "must be a valid oop");
1382 if (!_bitmap->isMarked((HeapWord*) obj)) {
1383 _bitmap->mark((HeapWord*) obj);
1384 _oop_stack->push(obj);
1385 }
1386 }
1387 }
1388 public:
1389 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1390 _bitmap(bitmap), _oop_stack(oop_stack) {}
1391 void do_oop(oop* p) { do_oop_work(p); }
1392 void do_oop(narrowOop* p) { do_oop_work(p); }
1393 };
1394
1395 /*
1396 * This is public API, used in preparation of object_iterate().
1397 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1398 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1399 * control, we call SH::make_tlabs_parsable().
1400 */
1401 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1402 // No-op.
1403 }
1404
1405 /*
1406 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1407 *
1408 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1409 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1410 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1411 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1412 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1413 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1414 * wiped the bitmap in preparation for next marking).
1415 *
1416 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1417 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1418 * is allowed to report dead objects, but is not required to do so.
1419 */
1420 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1421 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1422 if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1423 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1424 return;
1425 }
1426
1427 Stack<oop,mtGC> oop_stack;
1428
1429 // First, we process all GC roots. This populates the work stack with initial objects.
1430 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1431 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1432 CLDToOopClosure clds(&oops, false);
1433 CodeBlobToOopClosure blobs(&oops, false);
1434 rp.process_all_roots(&oops, &oops, &clds, &blobs, 0);
1435
1436 // Work through the oop stack to traverse heap.
1437 while (! oop_stack.is_empty()) {
1438 oop obj = oop_stack.pop();
1439 assert(oopDesc::is_oop(obj), "must be a valid oop");
1440 cl->do_object(obj);
1441 obj->oop_iterate(&oops);
1442 }
1443
1444 assert(oop_stack.is_empty(), "should be empty");
1445
1446 if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1447 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1448 }
1449 }
1450
1451 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1452 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1453 object_iterate(cl);
1454 }
1455
1456 // Apply blk->heap_region_do() on all committed regions in address order,
1457 // terminating the iteration early if heap_region_do() returns true.
1458 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk, bool skip_cset_regions, bool skip_humongous_continuation) const {
1459 for (size_t i = 0; i < num_regions(); i++) {
1460 ShenandoahHeapRegion* current = _ordered_regions->get(i);
1461 if (skip_humongous_continuation && current->is_humongous_continuation()) {
1462 continue;
1463 }
1464 if (skip_cset_regions && in_collection_set(current)) {
1465 continue;
1466 }
1467 if (blk->heap_region_do(current)) {
1468 return;
1469 }
1470 }
1471 }
1472
1473 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1474 private:
1475 ShenandoahHeap* sh;
1476 public:
1477 ShenandoahClearLivenessClosure(ShenandoahHeap* heap) : sh(heap) {}
1478
1479 bool heap_region_do(ShenandoahHeapRegion* r) {
1480 r->clear_live_data();
1481 sh->set_next_top_at_mark_start(r->bottom(), r->top());
1482 return false;
1483 }
1484 };
1485
1486 void ShenandoahHeap::start_concurrent_marking() {
1487 if (ShenandoahVerify) {
1488 verifier()->verify_before_concmark();
1489 }
1490
1491 {
1492 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats);
1493 accumulate_statistics_all_tlabs();
1494 }
1495
1496 set_concurrent_mark_in_progress(true);
1497 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1498 if (UseTLAB) {
1499 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1500 make_tlabs_parsable(true);
1501 }
1502
1503 _shenandoah_policy->record_bytes_allocated(_bytes_allocated_since_cm);
1504 _used_start_gc = used();
1505
1506 {
1507 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1508 ShenandoahClearLivenessClosure clc(this);
1509 heap_region_iterate(&clc);
1510 }
1511
1512 // Make above changes visible to worker threads
1513 OrderAccess::fence();
1514
1515 concurrentMark()->init_mark_roots();
1516
1517 if (UseTLAB) {
1518 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1519 resize_all_tlabs();
1520 }
1521 }
1522
1523 void ShenandoahHeap::swap_mark_bitmaps() {
1524 // Swap bitmaps.
1525 MarkBitMap* tmp1 = _complete_mark_bit_map;
1526 _complete_mark_bit_map = _next_mark_bit_map;
1527 _next_mark_bit_map = tmp1;
1528
1529 // Swap top-at-mark-start pointers
1530 HeapWord** tmp2 = _complete_top_at_mark_starts;
1531 _complete_top_at_mark_starts = _next_top_at_mark_starts;
1532 _next_top_at_mark_starts = tmp2;
1533
1534 HeapWord** tmp3 = _complete_top_at_mark_starts_base;
1535 _complete_top_at_mark_starts_base = _next_top_at_mark_starts_base;
1536 _next_top_at_mark_starts_base = tmp3;
1537 }
1538
1539
1540 void ShenandoahHeap::stop_concurrent_marking() {
1541 assert(concurrent_mark_in_progress(), "How else could we get here?");
1542 if (! cancelled_concgc()) {
1543 // If we needed to update refs, and concurrent marking has been cancelled,
1544 // we need to finish updating references.
1545 set_need_update_refs(false);
1546 swap_mark_bitmaps();
1547 }
1548 set_concurrent_mark_in_progress(false);
1549
1550 LogTarget(Trace, gc, region) lt;
1551 if (lt.is_enabled()) {
1552 ResourceMark rm;
1553 LogStream ls(lt);
1554 ls.print_cr("Regions at stopping the concurrent mark:");
1555 print_heap_regions_on(&ls);
1556 }
1557 }
1558
1559 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1560 _concurrent_mark_in_progress = in_progress ? 1 : 0;
1561 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1562 }
1563
1564 void ShenandoahHeap::set_concurrent_partial_in_progress(bool in_progress) {
1565 _concurrent_partial_in_progress = in_progress;
1566 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1567 set_evacuation_in_progress_at_safepoint(in_progress);
1568 }
1569
1570 void ShenandoahHeap::set_evacuation_in_progress_concurrently(bool in_progress) {
1571 // Note: it is important to first release the _evacuation_in_progress flag here,
1572 // so that Java threads can get out of oom_during_evacuation() and reach a safepoint,
1573 // in case a VM task is pending.
1574 set_evacuation_in_progress(in_progress);
1575 MutexLocker mu(Threads_lock);
1576 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1577 }
1578
1579 void ShenandoahHeap::set_evacuation_in_progress_at_safepoint(bool in_progress) {
1580 assert(SafepointSynchronize::is_at_safepoint(), "Only call this at safepoint");
1581 set_evacuation_in_progress(in_progress);
1582 JavaThread::set_evacuation_in_progress_all_threads(in_progress);
1583 }
1584
1585 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1586 _evacuation_in_progress = in_progress ? 1 : 0;
1587 OrderAccess::fence();
1588 }
1589
1590 void ShenandoahHeap::oom_during_evacuation() {
1591 log_develop_trace(gc)("Out of memory during evacuation, cancel evacuation, schedule full GC by thread %d",
1592 Thread::current()->osthread()->thread_id());
1593
1594 // We ran out of memory during evacuation. Cancel evacuation, and schedule a full-GC.
1595 collector_policy()->set_should_clear_all_soft_refs(true);
1596 concurrent_thread()->try_set_full_gc();
1597 cancel_concgc(_oom_evacuation);
1598
1599 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
1600 assert(! Threads_lock->owned_by_self()
1601 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here");
1602 log_warning(gc)("OOM during evacuation. Let Java thread wait until evacuation finishes.");
1603 while (_evacuation_in_progress) { // wait.
1604 Thread::current()->_ParkEvent->park(1);
1605 }
1606 }
1607
1608 }
1609
1610 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1611 // Initialize Brooks pointer for the next object
1612 HeapWord* result = obj + BrooksPointer::word_size();
1613 BrooksPointer::initialize(oop(result));
1614 return result;
1615 }
1616
1617 uint ShenandoahHeap::oop_extra_words() {
1618 return BrooksPointer::word_size();
1619 }
1620
1621 ShenandoahForwardedIsAliveClosure::ShenandoahForwardedIsAliveClosure() :
1622 _heap(ShenandoahHeap::heap_no_check()) {
1623 }
1624
1625 bool ShenandoahForwardedIsAliveClosure::do_object_b(oop obj) {
1626 assert(_heap != NULL, "sanity");
1627 obj = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
1628 #ifdef ASSERT
1629 if (_heap->concurrent_mark_in_progress()) {
1630 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1631 }
1632 #endif
1633 assert(!oopDesc::is_null(obj), "null");
1634 return _heap->is_marked_next(obj);
1635 }
1636
1637 ShenandoahIsAliveClosure::ShenandoahIsAliveClosure() :
1638 _heap(ShenandoahHeap::heap_no_check()) {
1639 }
1640
1641 bool ShenandoahIsAliveClosure::do_object_b(oop obj) {
1642 assert(_heap != NULL, "sanity");
1643 assert(!oopDesc::is_null(obj), "null");
1644 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "only query to-space");
1645 return _heap->is_marked_next(obj);
1646 }
1647
1648 BoolObjectClosure* ShenandoahHeap::is_alive_closure() {
1649 return need_update_refs() ?
1650 (BoolObjectClosure*) &_forwarded_is_alive :
1651 (BoolObjectClosure*) &_is_alive;
1652 }
1653
1654 void ShenandoahHeap::ref_processing_init() {
1655 MemRegion mr = reserved_region();
1656
1657 _forwarded_is_alive.init(ShenandoahHeap::heap());
1658 _is_alive.init(ShenandoahHeap::heap());
1659 assert(_max_workers > 0, "Sanity");
1660
1661 _ref_processor =
1662 new ReferenceProcessor(mr, // span
1663 ParallelRefProcEnabled, // MT processing
1664 _max_workers, // Degree of MT processing
1665 true, // MT discovery
1666 _max_workers, // Degree of MT discovery
1667 false, // Reference discovery is not atomic
1668 &_forwarded_is_alive); // Pessimistically assume "forwarded"
1669 }
1670
1671
1672 GCTracer* ShenandoahHeap::tracer() {
1673 return shenandoahPolicy()->tracer();
1674 }
1675
1676 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1677 return _free_regions->used();
1678 }
1679
1680 void ShenandoahHeap::cancel_concgc(GCCause::Cause cause) {
1681 if (try_cancel_concgc()) {
1682 log_info(gc)("Cancelling concurrent GC: %s", GCCause::to_string(cause));
1683 _shenandoah_policy->report_concgc_cancelled();
1684 }
1685 }
1686
1687 void ShenandoahHeap::cancel_concgc(ShenandoahCancelCause cause) {
1688 if (try_cancel_concgc()) {
1689 log_info(gc)("Cancelling concurrent GC: %s", cancel_cause_to_string(cause));
1690 _shenandoah_policy->report_concgc_cancelled();
1691 }
1692 }
1693
1694 const char* ShenandoahHeap::cancel_cause_to_string(ShenandoahCancelCause cause) {
1695 switch (cause) {
1696 case _oom_evacuation:
1697 return "Out of memory for evacuation";
1698 case _vm_stop:
1699 return "Stopping VM";
1700 default:
1701 return "Unknown";
1702 }
1703 }
1704
1705 uint ShenandoahHeap::max_workers() {
1706 return _max_workers;
1707 }
1708
1709 void ShenandoahHeap::stop() {
1710 // The shutdown sequence should be able to terminate when GC is running.
1711
1712 // Step 0. Notify policy to disable event recording.
1713 _shenandoah_policy->record_shutdown();
1714
1715 // Step 1. Notify control thread that we are in shutdown.
1716 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1717 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1718 _concurrent_gc_thread->prepare_for_graceful_shutdown();
1719
1720 // Step 2. Notify GC workers that we are cancelling GC.
1721 cancel_concgc(_vm_stop);
1722
1723 // Step 3. Wait until GC worker exits normally.
1724 _concurrent_gc_thread->stop();
1725 }
1726
1727 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1728 ShenandoahPhaseTimings::Phase phase_root =
1729 full_gc ?
1730 ShenandoahPhaseTimings::full_gc_purge :
1731 ShenandoahPhaseTimings::purge;
1732
1733 ShenandoahPhaseTimings::Phase phase_unload =
1734 full_gc ?
1735 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1736 ShenandoahPhaseTimings::purge_class_unload;
1737
1738 ShenandoahPhaseTimings::Phase phase_cldg =
1739 full_gc ?
1740 ShenandoahPhaseTimings::full_gc_purge_cldg :
1741 ShenandoahPhaseTimings::purge_cldg;
1742
1743 ShenandoahPhaseTimings::Phase phase_par =
1744 full_gc ?
1745 ShenandoahPhaseTimings::full_gc_purge_par :
1746 ShenandoahPhaseTimings::purge_par;
1747
1748 ShenandoahPhaseTimings::Phase phase_par_classes =
1749 full_gc ?
1750 ShenandoahPhaseTimings::full_gc_purge_par_classes :
1751 ShenandoahPhaseTimings::purge_par_classes;
1752
1753 ShenandoahPhaseTimings::Phase phase_par_codecache =
1754 full_gc ?
1755 ShenandoahPhaseTimings::full_gc_purge_par_codecache :
1756 ShenandoahPhaseTimings::purge_par_codecache;
1757
1758 ShenandoahPhaseTimings::Phase phase_par_rmt =
1759 full_gc ?
1760 ShenandoahPhaseTimings::full_gc_purge_par_rmt :
1761 ShenandoahPhaseTimings::purge_par_rmt;
1762
1763 ShenandoahPhaseTimings::Phase phase_par_symbstring =
1764 full_gc ?
1765 ShenandoahPhaseTimings::full_gc_purge_par_symbstring :
1766 ShenandoahPhaseTimings::purge_par_symbstring;
1767
1768 ShenandoahPhaseTimings::Phase phase_par_sync =
1769 full_gc ?
1770 ShenandoahPhaseTimings::full_gc_purge_par_sync :
1771 ShenandoahPhaseTimings::purge_par_sync;
1772
1773 ShenandoahGCPhase root_phase(phase_root);
1774
1775 BoolObjectClosure* is_alive = is_alive_closure();
1776
1777 bool purged_class;
1778
1779 // Unload classes and purge SystemDictionary.
1780 {
1781 ShenandoahGCPhase phase(phase_unload);
1782 purged_class = SystemDictionary::do_unloading(is_alive,
1783 full_gc ? ShenandoahMarkCompact::gc_timer() : gc_timer(),
1784 true);
1785 }
1786
1787 {
1788 ShenandoahGCPhase phase(phase_par);
1789 uint active = _workers->active_workers();
1790 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class);
1791 _workers->run_task(&unlink_task);
1792
1793 ShenandoahPhaseTimings* p = ShenandoahHeap::heap()->phase_timings();
1794 ParallelCleaningTimes times = unlink_task.times();
1795
1796 // "times" report total time, phase_tables_cc reports wall time. Divide total times
1797 // by active workers to get average time per worker, that would add up to wall time.
1798 p->record_phase_time(phase_par_classes, times.klass_work_us() / active);
1799 p->record_phase_time(phase_par_codecache, times.codecache_work_us() / active);
1800 p->record_phase_time(phase_par_rmt, times.rmt_work_us() / active);
1801 p->record_phase_time(phase_par_symbstring, times.tables_work_us() / active);
1802 p->record_phase_time(phase_par_sync, times.sync_us() / active);
1803 }
1804
1805 {
1806 ShenandoahGCPhase phase(phase_cldg);
1807 ClassLoaderDataGraph::purge();
1808 }
1809 }
1810
1811 void ShenandoahHeap::set_need_update_refs(bool need_update_refs) {
1812 _need_update_refs = need_update_refs;
1813 }
1814
1815 //fixme this should be in heapregionset
1816 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
1817 size_t region_idx = r->region_number() + 1;
1818 ShenandoahHeapRegion* next = _ordered_regions->get(region_idx);
1819 guarantee(next->region_number() == region_idx, "region number must match");
1820 while (next->is_humongous()) {
1821 region_idx = next->region_number() + 1;
1822 next = _ordered_regions->get(region_idx);
1823 guarantee(next->region_number() == region_idx, "region number must match");
1824 }
1825 return next;
1826 }
1827
1828 ShenandoahMonitoringSupport* ShenandoahHeap::monitoring_support() {
1829 return _monitoring_support;
1830 }
1831
1832 MarkBitMap* ShenandoahHeap::complete_mark_bit_map() {
1833 return _complete_mark_bit_map;
1834 }
1835
1836 MarkBitMap* ShenandoahHeap::next_mark_bit_map() {
1837 return _next_mark_bit_map;
1838 }
1839
1840 void ShenandoahHeap::add_free_region(ShenandoahHeapRegion* r) {
1841 _free_regions->add_region(r);
1842 }
1843
1844 void ShenandoahHeap::clear_free_regions() {
1845 _free_regions->clear();
1846 }
1847
1848 address ShenandoahHeap::in_cset_fast_test_addr() {
1849 ShenandoahHeap* heap = ShenandoahHeap::heap();
1850 assert(heap->collection_set() != NULL, "Sanity");
1851 return (address) heap->collection_set()->biased_map_address();
1852 }
1853
1854 address ShenandoahHeap::cancelled_concgc_addr() {
1855 return (address) &(ShenandoahHeap::heap()->_cancelled_concgc);
1856 }
1857
1858
1859 size_t ShenandoahHeap::conservative_max_heap_alignment() {
1860 return ShenandoahMaxRegionSize;
1861 }
1862
1863 size_t ShenandoahHeap::bytes_allocated_since_cm() {
1864 return _bytes_allocated_since_cm;
1865 }
1866
1867 void ShenandoahHeap::set_bytes_allocated_since_cm(size_t bytes) {
1868 _bytes_allocated_since_cm = bytes;
1869 }
1870
1871 void ShenandoahHeap::set_next_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
1872 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1873 _next_top_at_mark_starts[index] = addr;
1874 }
1875
1876 HeapWord* ShenandoahHeap::next_top_at_mark_start(HeapWord* region_base) {
1877 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1878 return _next_top_at_mark_starts[index];
1879 }
1880
1881 void ShenandoahHeap::set_complete_top_at_mark_start(HeapWord* region_base, HeapWord* addr) {
1882 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1883 _complete_top_at_mark_starts[index] = addr;
1884 }
1885
1886 HeapWord* ShenandoahHeap::complete_top_at_mark_start(HeapWord* region_base) {
1887 uintx index = ((uintx) region_base) >> ShenandoahHeapRegion::region_size_bytes_shift();
1888 return _complete_top_at_mark_starts[index];
1889 }
1890
1891 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
1892 _full_gc_in_progress = in_progress;
1893 }
1894
1895 bool ShenandoahHeap::is_full_gc_in_progress() const {
1896 return _full_gc_in_progress;
1897 }
1898
1899 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
1900 _update_refs_in_progress = in_progress;
1901 }
1902
1903 bool ShenandoahHeap::is_update_refs_in_progress() const {
1904 return _update_refs_in_progress;
1905 }
1906
1907 void ShenandoahHeap::register_nmethod(nmethod* nm) {
1908 ShenandoahCodeRoots::add_nmethod(nm);
1909 }
1910
1911 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
1912 ShenandoahCodeRoots::remove_nmethod(nm);
1913 }
1914
1915 void ShenandoahHeap::pin_object(oop o) {
1916 ShenandoahHeapLocker locker(lock());
1917 heap_region_containing(o)->make_pinned();
1918 }
1919
1920 void ShenandoahHeap::unpin_object(oop o) {
1921 ShenandoahHeapLocker locker(lock());
1922 heap_region_containing(o)->make_unpinned();
1923 }
1924
1925 GCTimer* ShenandoahHeap::gc_timer() const {
1926 return _gc_timer;
1927 }
1928
1929 #ifdef ASSERT
1930 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
1931 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
1932
1933 if (SafepointSynchronize::is_at_safepoint()) {
1934 if (UseDynamicNumberOfGCThreads ||
1935 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
1936 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
1937 } else {
1938 // Use ParallelGCThreads inside safepoints
1939 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
1940 }
1941 } else {
1942 if (UseDynamicNumberOfGCThreads ||
1943 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
1944 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
1945 } else {
1946 // Use ConcGCThreads outside safepoints
1947 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
1948 }
1949 }
1950 }
1951 #endif
1952
1953 class ShenandoahCountGarbageClosure : public ShenandoahHeapRegionClosure {
1954 private:
1955 size_t _garbage;
1956 public:
1957 ShenandoahCountGarbageClosure() : _garbage(0) {
1958 }
1959
1960 bool heap_region_do(ShenandoahHeapRegion* r) {
1961 if (r->is_regular()) {
1962 _garbage += r->garbage();
1963 }
1964 return false;
1965 }
1966
1967 size_t garbage() {
1968 return _garbage;
1969 }
1970 };
1971
1972 size_t ShenandoahHeap::garbage() {
1973 ShenandoahCountGarbageClosure cl;
1974 heap_region_iterate(&cl);
1975 return cl.garbage();
1976 }
1977
1978 ShenandoahConnectionMatrix* ShenandoahHeap::connection_matrix() const {
1979 return _connection_matrix;
1980 }
1981
1982 ShenandoahPartialGC* ShenandoahHeap::partial_gc() {
1983 return _partial_gc;
1984 }
1985
1986 ShenandoahVerifier* ShenandoahHeap::verifier() {
1987 guarantee(ShenandoahVerify, "Should be enabled");
1988 assert (_verifier != NULL, "sanity");
1989 return _verifier;
1990 }
1991
1992 template<class T>
1993 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
1994 private:
1995 T cl;
1996 ShenandoahHeap* _heap;
1997 ShenandoahHeapRegionSet* _regions;
1998 bool _concurrent;
1999 public:
2000 ShenandoahUpdateHeapRefsTask(ShenandoahHeapRegionSet* regions, bool concurrent) :
2001 AbstractGangTask("Concurrent Update References Task"),
2002 cl(T()),
2003 _heap(ShenandoahHeap::heap()),
2004 _regions(regions),
2005 _concurrent(concurrent) {
2006 }
2007
2008 void work(uint worker_id) {
2009 SuspendibleThreadSetJoiner stsj(_concurrent && ShenandoahSuspendibleWorkers);
2010 ShenandoahHeapRegion* r = _regions->claim_next();
2011 while (r != NULL) {
2012 if (_heap->in_collection_set(r)) {
2013 HeapWord* bottom = r->bottom();
2014 HeapWord* top = _heap->complete_top_at_mark_start(r->bottom());
2015 if (top > bottom) {
2016 _heap->complete_mark_bit_map()->clear_range_large(MemRegion(bottom, top));
2017 }
2018 } else {
2019 if (r->is_active()) {
2020 _heap->marked_object_oop_safe_iterate(r, &cl);
2021 }
2022 }
2023 if (_heap->check_cancelled_concgc_and_yield(_concurrent)) {
2024 return;
2025 }
2026 r = _regions->claim_next();
2027 }
2028 }
2029 };
2030
2031 void ShenandoahHeap::update_heap_references(ShenandoahHeapRegionSet* update_regions, bool concurrent) {
2032 if (UseShenandoahMatrix) {
2033 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsMatrixClosure> task(update_regions, concurrent);
2034 workers()->run_task(&task);
2035 } else {
2036 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(update_regions, concurrent);
2037 workers()->run_task(&task);
2038 }
2039 }
2040
2041 void ShenandoahHeap::concurrent_update_heap_references() {
2042 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2043 ShenandoahHeapRegionSet* update_regions = regions();
2044 update_regions->clear_current_index();
2045 update_heap_references(update_regions, true);
2046 }
2047
2048 void ShenandoahHeap::prepare_update_refs() {
2049 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2050
2051 if (ShenandoahVerify) {
2052 verifier()->verify_before_updaterefs();
2053 }
2054
2055 set_evacuation_in_progress_at_safepoint(false);
2056 set_update_refs_in_progress(true);
2057 make_tlabs_parsable(true);
2058 if (UseShenandoahMatrix) {
2059 connection_matrix()->clear_all();
2060 }
2061 for (uint i = 0; i < num_regions(); i++) {
2062 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2063 r->set_concurrent_iteration_safe_limit(r->top());
2064 }
2065 }
2066
2067 void ShenandoahHeap::finish_update_refs() {
2068 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2069
2070 if (cancelled_concgc()) {
2071 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2072
2073 // Finish updating references where we left off.
2074 clear_cancelled_concgc();
2075 ShenandoahHeapRegionSet* update_regions = regions();
2076 update_heap_references(update_regions, false);
2077 }
2078
2079 assert(! cancelled_concgc(), "Should have been done right before");
2080 concurrentMark()->update_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2081
2082 if (ShenandoahStringDedup::is_enabled()) {
2083 ShenandoahGCPhase final_str_dedup_table(ShenandoahPhaseTimings::final_update_refs_dedup_table);
2084 ShenandoahStringDedup::parallel_update_or_unlink();
2085 }
2086
2087 // Allocations might have happened before we STWed here, record peak:
2088 shenandoahPolicy()->record_peak_occupancy();
2089
2090 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2091
2092 trash_cset_regions();
2093 set_need_update_refs(false);
2094
2095 if (ShenandoahVerify) {
2096 verifier()->verify_after_updaterefs();
2097 }
2098
2099 {
2100 // Rebuild the free set
2101 ShenandoahHeapLocker locker(lock());
2102 _free_regions->clear();
2103 size_t end = _ordered_regions->active_regions();
2104 for (size_t i = 0; i < end; i++) {
2105 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2106 if (r->is_alloc_allowed()) {
2107 assert (!in_collection_set(r), "collection set should be clear");
2108 _free_regions->add_region(r);
2109 }
2110 }
2111 }
2112 set_update_refs_in_progress(false);
2113 }
2114
2115 void ShenandoahHeap::set_alloc_seq_gc_start() {
2116 // Take next number, the start seq number is inclusive
2117 _alloc_seq_at_last_gc_start = ShenandoahHeapRegion::alloc_seq_num() + 1;
2118 }
2119
2120 void ShenandoahHeap::set_alloc_seq_gc_end() {
2121 // Take current number, the end seq number is also inclusive
2122 _alloc_seq_at_last_gc_end = ShenandoahHeapRegion::alloc_seq_num();
2123 }
2124
2125
2126 #ifdef ASSERT
2127 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2128 _lock.assert_owned_by_current_thread();
2129 }
2130
2131 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2132 _lock.assert_not_owned_by_current_thread();
2133 }
2134
2135 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2136 _lock.assert_owned_by_current_thread_or_safepoint();
2137 }
2138 #endif
2139
2140 void ShenandoahHeap::recycle_trash_assist(size_t limit) {
2141 assert_heaplock_owned_by_current_thread();
2142
2143 size_t count = 0;
2144 for (size_t i = 0; (i < num_regions()) && (count < limit); i++) {
2145 ShenandoahHeapRegion *r = _ordered_regions->get(i);
2146 if (r->is_trash()) {
2147 decrease_used(r->used());
2148 r->recycle();
2149 _free_regions->add_region(r);
2150 count++;
2151 }
2152 }
2153 }
2154
2155 void ShenandoahHeap::recycle_trash() {
2156 // lock is not reentrable, check we don't have it
2157 assert_heaplock_not_owned_by_current_thread();
2158
2159 size_t bytes_reclaimed = 0;
2160
2161 for (size_t i = 0; i < num_regions(); i++) {
2162 ShenandoahHeapRegion* r = _ordered_regions->get(i);
2163 if (r->is_trash()) {
2164 ShenandoahHeapLocker locker(lock());
2165 if (r->is_trash()) {
2166 bytes_reclaimed += r->used();
2167 decrease_used(r->used());
2168 r->recycle();
2169 _free_regions->add_region(r);
2170 }
2171 }
2172 SpinPause(); // allow allocators to take the lock
2173 }
2174
2175 _shenandoah_policy->record_bytes_reclaimed(bytes_reclaimed);
2176 }
2177
2178 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2179 print_on(st);
2180 print_heap_regions_on(st);
2181 }
2182
2183 address ShenandoahHeap::concurrent_mark_in_progress_addr() {
2184 return (address) &(ShenandoahHeap::heap()->_concurrent_mark_in_progress);
2185 }
2186
2187 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2188 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2189
2190 size_t regions_from = _bitmap_regions_per_slice * slice;
2191 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2192 for (size_t g = regions_from; g < regions_to; g++) {
2193 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2194 if (skip_self && g == r->region_number()) continue;
2195 if (_ordered_regions->get(g)->is_committed()) {
2196 return true;
2197 }
2198 }
2199 return false;
2200 }
2201
2202 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2203 assert_heaplock_owned_by_current_thread();
2204
2205 if (is_bitmap_slice_committed(r, true)) {
2206 // Some other region from the group is already committed, meaning the bitmap
2207 // slice is already committed, we exit right away.
2208 return true;
2209 }
2210
2211 // Commit the bitmap slice:
2212 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2213 size_t off = _bitmap_bytes_per_slice * slice;
2214 size_t len = _bitmap_bytes_per_slice;
2215 if (!os::commit_memory((char*)_bitmap0_region.start() + off, len, false)) {
2216 return false;
2217 }
2218 if (!os::commit_memory((char*)_bitmap1_region.start() + off, len, false)) {
2219 return false;
2220 }
2221 return true;
2222 }
2223
2224 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2225 assert_heaplock_owned_by_current_thread();
2226
2227 if (is_bitmap_slice_committed(r, true)) {
2228 // Some other region from the group is still committed, meaning the bitmap
2229 // slice is should stay committed, exit right away.
2230 return true;
2231 }
2232
2233 // Uncommit the bitmap slice:
2234 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2235 size_t off = _bitmap_bytes_per_slice * slice;
2236 size_t len = _bitmap_bytes_per_slice;
2237 if (!os::uncommit_memory((char*)_bitmap0_region.start() + off, len)) {
2238 return false;
2239 }
2240 if (!os::uncommit_memory((char*)_bitmap1_region.start() + off, len)) {
2241 return false;
2242 }
2243 return true;
2244 }