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