1 /*
2 * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/universe.hpp"
28
29 #include "gc/shared/gcArguments.hpp"
30 #include "gc/shared/gcTimer.hpp"
31 #include "gc/shared/gcTraceTime.inline.hpp"
32 #include "gc/shared/locationPrinter.inline.hpp"
33 #include "gc/shared/memAllocator.hpp"
34 #include "gc/shared/oopStorageSet.hpp"
35 #include "gc/shared/plab.hpp"
36
37 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
38 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
39 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
40 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
41 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
42 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
43 #include "gc/shenandoah/shenandoahControlThread.hpp"
44 #include "gc/shenandoah/shenandoahFreeSet.hpp"
45 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
46 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
47 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
48 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
49 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
50 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
51 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
52 #include "gc/shenandoah/shenandoahMetrics.hpp"
53 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
54 #include "gc/shenandoah/shenandoahNormalMode.hpp"
55 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
56 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
57 #include "gc/shenandoah/shenandoahPadding.hpp"
58 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp"
59 #include "gc/shenandoah/shenandoahPassiveMode.hpp"
60 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
61 #include "gc/shenandoah/shenandoahStringDedup.hpp"
62 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
63 #include "gc/shenandoah/shenandoahTraversalMode.hpp"
64 #include "gc/shenandoah/shenandoahUtils.hpp"
65 #include "gc/shenandoah/shenandoahVerifier.hpp"
66 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
67 #include "gc/shenandoah/shenandoahVMOperations.hpp"
68 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
69 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
70 #if INCLUDE_JFR
71 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
72 #endif
73
74 #include "memory/metaspace.hpp"
75 #include "oops/compressedOops.inline.hpp"
76 #include "runtime/atomic.hpp"
77 #include "runtime/globals.hpp"
78 #include "runtime/interfaceSupport.inline.hpp"
79 #include "runtime/orderAccess.hpp"
80 #include "runtime/safepointMechanism.hpp"
81 #include "runtime/vmThread.hpp"
82 #include "services/mallocTracker.hpp"
83 #include "utilities/powerOfTwo.hpp"
84
85 ShenandoahHeap* ShenandoahHeap::_heap = NULL;
86
87 #ifdef ASSERT
88 template <class T>
89 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
90 T o = RawAccess<>::oop_load(p);
91 if (! CompressedOops::is_null(o)) {
92 oop obj = CompressedOops::decode_not_null(o);
93 shenandoah_assert_not_forwarded(p, obj);
94 }
95 }
96
97 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
98 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
99 #endif
100
101 class ShenandoahPretouchHeapTask : public AbstractGangTask {
102 private:
103 ShenandoahRegionIterator _regions;
104 const size_t _page_size;
105 public:
106 ShenandoahPretouchHeapTask(size_t page_size) :
107 AbstractGangTask("Shenandoah Pretouch Heap"),
108 _page_size(page_size) {}
109
110 virtual void work(uint worker_id) {
111 ShenandoahHeapRegion* r = _regions.next();
112 while (r != NULL) {
113 os::pretouch_memory(r->bottom(), r->end(), _page_size);
114 r = _regions.next();
115 }
116 }
117 };
118
119 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
120 private:
121 ShenandoahRegionIterator _regions;
122 char* _bitmap_base;
123 const size_t _bitmap_size;
124 const size_t _page_size;
125 public:
126 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
127 AbstractGangTask("Shenandoah Pretouch Bitmap"),
128 _bitmap_base(bitmap_base),
129 _bitmap_size(bitmap_size),
130 _page_size(page_size) {}
131
132 virtual void work(uint worker_id) {
133 ShenandoahHeapRegion* r = _regions.next();
134 while (r != NULL) {
135 size_t start = r->index() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
136 size_t end = (r->index() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
137 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
138
139 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
140
141 r = _regions.next();
142 }
143 }
144 };
145
146 jint ShenandoahHeap::initialize() {
147 initialize_heuristics();
148
149 //
150 // Figure out heap sizing
151 //
152
153 size_t init_byte_size = InitialHeapSize;
154 size_t min_byte_size = MinHeapSize;
155 size_t max_byte_size = MaxHeapSize;
156 size_t heap_alignment = HeapAlignment;
157
158 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
159
160 if (ShenandoahAlwaysPreTouch) {
161 // Enabled pre-touch means the entire heap is committed right away.
162 init_byte_size = max_byte_size;
163 }
164
165 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
166 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
167
168 _num_regions = ShenandoahHeapRegion::region_count();
169
170 size_t num_committed_regions = init_byte_size / reg_size_bytes;
171 num_committed_regions = MIN2(num_committed_regions, _num_regions);
172 assert(num_committed_regions <= _num_regions, "sanity");
173 _initial_size = num_committed_regions * reg_size_bytes;
174
175 size_t num_min_regions = min_byte_size / reg_size_bytes;
176 num_min_regions = MIN2(num_min_regions, _num_regions);
177 assert(num_min_regions <= _num_regions, "sanity");
178 _minimum_size = num_min_regions * reg_size_bytes;
179
180 _committed = _initial_size;
181
182 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
183 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
184 size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
185
186 //
187 // Reserve and commit memory for heap
188 //
189
190 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
191 initialize_reserved_region(heap_rs);
192 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
193 _heap_region_special = heap_rs.special();
194
195 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
196 "Misaligned heap: " PTR_FORMAT, p2i(base()));
197
198 #if SHENANDOAH_OPTIMIZED_OBJTASK
199 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits.
200 // Fail if we ever attempt to address more than we can.
201 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) {
202 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n"
203 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n"
204 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).",
205 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable());
206 vm_exit_during_initialization("Fatal Error", buf);
207 }
208 #endif
209
210 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
211 if (!_heap_region_special) {
212 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
213 "Cannot commit heap memory");
214 }
215
216 //
217 // Reserve and commit memory for bitmap(s)
218 //
219
220 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
221 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
222
223 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
224
225 guarantee(bitmap_bytes_per_region != 0,
226 "Bitmap bytes per region should not be zero");
227 guarantee(is_power_of_2(bitmap_bytes_per_region),
228 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
229
230 if (bitmap_page_size > bitmap_bytes_per_region) {
231 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
232 _bitmap_bytes_per_slice = bitmap_page_size;
233 } else {
234 _bitmap_regions_per_slice = 1;
235 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
236 }
237
238 guarantee(_bitmap_regions_per_slice >= 1,
239 "Should have at least one region per slice: " SIZE_FORMAT,
240 _bitmap_regions_per_slice);
241
242 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
243 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
244 _bitmap_bytes_per_slice, bitmap_page_size);
245
246 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
247 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
248 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
249 _bitmap_region_special = bitmap.special();
250
251 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
252 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
253 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
254 if (!_bitmap_region_special) {
255 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
256 "Cannot commit bitmap memory");
257 }
258
259 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
260
261 if (ShenandoahVerify) {
262 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
263 if (!verify_bitmap.special()) {
264 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
265 "Cannot commit verification bitmap memory");
266 }
267 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
268 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
269 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
270 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
271 }
272
273 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
274 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
275 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
276 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
277 _aux_bitmap_region_special = aux_bitmap.special();
278 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
279
280 //
281 // Create regions and region sets
282 //
283 size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE);
284 size_t region_storage_size = align_up(region_align * _num_regions, region_page_size);
285
286 ReservedSpace region_storage(region_storage_size, region_page_size);
287 MemTracker::record_virtual_memory_type(region_storage.base(), mtGC);
288 if (!region_storage.special()) {
289 os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false,
290 "Cannot commit region memory");
291 }
292
293 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
294 _free_set = new ShenandoahFreeSet(this, _num_regions);
295 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
296
297 {
298 ShenandoahHeapLocker locker(lock());
299
300 for (size_t i = 0; i < _num_regions; i++) {
301 HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i;
302 bool is_committed = i < num_committed_regions;
303 void* loc = region_storage.base() + i * region_align;
304
305 ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed);
306 assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity");
307
308 _marking_context->initialize_top_at_mark_start(r);
309 _regions[i] = r;
310 assert(!collection_set()->is_in(i), "New region should not be in collection set");
311 }
312
313 // Initialize to complete
314 _marking_context->mark_complete();
315
316 _free_set->rebuild();
317 }
318
319 if (ShenandoahAlwaysPreTouch) {
320 assert(!AlwaysPreTouch, "Should have been overridden");
321
322 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
323 // before initialize() below zeroes it with initializing thread. For any given region,
324 // we touch the region and the corresponding bitmaps from the same thread.
325 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
326
327 size_t pretouch_heap_page_size = heap_page_size;
328 size_t pretouch_bitmap_page_size = bitmap_page_size;
329
330 #ifdef LINUX
331 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
332 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
333 // them into huge one. Therefore, we need to pretouch with smaller pages.
334 if (UseTransparentHugePages) {
335 pretouch_heap_page_size = (size_t)os::vm_page_size();
336 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
337 }
338 #endif
339
340 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
341 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
342
343 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
344 _num_regions, pretouch_bitmap_page_size);
345 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
346 _workers->run_task(&bcl);
347
348 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
349 _num_regions, pretouch_heap_page_size);
350 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
351 _workers->run_task(&hcl);
352 }
353
354 //
355 // Initialize the rest of GC subsystems
356 //
357
358 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
359 for (uint worker = 0; worker < _max_workers; worker++) {
360 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
361 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
362 }
363
364 // There should probably be Shenandoah-specific options for these,
365 // just as there are G1-specific options.
366 {
367 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set();
368 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold
369 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent
370 }
371
372 _monitoring_support = new ShenandoahMonitoringSupport(this);
373 _phase_timings = new ShenandoahPhaseTimings();
374 ShenandoahStringDedup::initialize();
375 ShenandoahCodeRoots::initialize();
376
377 if (ShenandoahPacing) {
378 _pacer = new ShenandoahPacer(this);
379 _pacer->setup_for_idle();
380 } else {
381 _pacer = NULL;
382 }
383
384 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ?
385 new ShenandoahTraversalGC(this) :
386 NULL;
387
388 _control_thread = new ShenandoahControlThread();
389
390 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
391 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
392 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
393 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
394 );
395
396 log_info(gc, init)("Safepointing mechanism: thread-local poll");
397
398 return JNI_OK;
399 }
400
401 void ShenandoahHeap::initialize_heuristics() {
402 if (ShenandoahGCMode != NULL) {
403 if (strcmp(ShenandoahGCMode, "traversal") == 0) {
404 _gc_mode = new ShenandoahTraversalMode();
405 } else if (strcmp(ShenandoahGCMode, "normal") == 0) {
406 _gc_mode = new ShenandoahNormalMode();
407 } else if (strcmp(ShenandoahGCMode, "passive") == 0) {
408 _gc_mode = new ShenandoahPassiveMode();
409 } else {
410 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
411 }
412 } else {
413 ShouldNotReachHere();
414 }
415 _gc_mode->initialize_flags();
416 _heuristics = _gc_mode->initialize_heuristics();
417
418 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
419 vm_exit_during_initialization(
420 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
421 _heuristics->name()));
422 }
423 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
424 vm_exit_during_initialization(
425 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
426 _heuristics->name()));
427 }
428 log_info(gc, init)("Shenandoah heuristics: %s",
429 _heuristics->name());
430 }
431
432 #ifdef _MSC_VER
433 #pragma warning( push )
434 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
435 #endif
436
437 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
438 CollectedHeap(),
439 _initial_size(0),
440 _used(0),
441 _committed(0),
442 _bytes_allocated_since_gc_start(0),
443 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
444 _workers(NULL),
445 _safepoint_workers(NULL),
446 _heap_region_special(false),
447 _num_regions(0),
448 _regions(NULL),
449 _update_refs_iterator(this),
450 _control_thread(NULL),
451 _shenandoah_policy(policy),
452 _heuristics(NULL),
453 _free_set(NULL),
454 _scm(new ShenandoahConcurrentMark()),
455 _traversal_gc(NULL),
456 _full_gc(new ShenandoahMarkCompact()),
457 _pacer(NULL),
458 _verifier(NULL),
459 _phase_timings(NULL),
460 _monitoring_support(NULL),
461 _memory_pool(NULL),
462 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
463 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
464 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
465 _soft_ref_policy(),
466 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
467 _ref_processor(NULL),
468 _marking_context(NULL),
469 _bitmap_size(0),
470 _bitmap_regions_per_slice(0),
471 _bitmap_bytes_per_slice(0),
472 _bitmap_region_special(false),
473 _aux_bitmap_region_special(false),
474 _liveness_cache(NULL),
475 _collection_set(NULL)
476 {
477 _heap = this;
478
479 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
480 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
481
482 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
483
484 _max_workers = MAX2(_max_workers, 1U);
485 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
486 /* are_GC_task_threads */ true,
487 /* are_ConcurrentGC_threads */ true);
488 if (_workers == NULL) {
489 vm_exit_during_initialization("Failed necessary allocation.");
490 } else {
491 _workers->initialize_workers();
492 }
493
494 if (ParallelGCThreads > 1) {
495 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
496 ParallelGCThreads,
497 /* are_GC_task_threads */ false,
498 /* are_ConcurrentGC_threads */ false);
499 _safepoint_workers->initialize_workers();
500 }
501 }
502
503 #ifdef _MSC_VER
504 #pragma warning( pop )
505 #endif
506
507 class ShenandoahResetBitmapTask : public AbstractGangTask {
508 private:
509 ShenandoahRegionIterator _regions;
510
511 public:
512 ShenandoahResetBitmapTask() :
513 AbstractGangTask("Parallel Reset Bitmap Task") {}
514
515 void work(uint worker_id) {
516 ShenandoahHeapRegion* region = _regions.next();
517 ShenandoahHeap* heap = ShenandoahHeap::heap();
518 ShenandoahMarkingContext* const ctx = heap->marking_context();
519 while (region != NULL) {
520 if (heap->is_bitmap_slice_committed(region)) {
521 ctx->clear_bitmap(region);
522 }
523 region = _regions.next();
524 }
525 }
526 };
527
528 void ShenandoahHeap::reset_mark_bitmap() {
529 assert_gc_workers(_workers->active_workers());
530 mark_incomplete_marking_context();
531
532 ShenandoahResetBitmapTask task;
533 _workers->run_task(&task);
534 }
535
536 void ShenandoahHeap::print_on(outputStream* st) const {
537 st->print_cr("Shenandoah Heap");
538 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used",
539 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()),
540 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()),
541 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used()));
542 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions",
543 num_regions(),
544 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()),
545 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes()));
546
547 st->print("Status: ");
548 if (has_forwarded_objects()) st->print("has forwarded objects, ");
549 if (is_concurrent_mark_in_progress()) st->print("marking, ");
550 if (is_evacuation_in_progress()) st->print("evacuating, ");
551 if (is_update_refs_in_progress()) st->print("updating refs, ");
552 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
553 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
554 if (is_full_gc_in_progress()) st->print("full gc, ");
555 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
556 if (is_concurrent_root_in_progress()) st->print("concurrent roots, ");
557
558 if (cancelled_gc()) {
559 st->print("cancelled");
560 } else {
561 st->print("not cancelled");
562 }
563 st->cr();
564
565 st->print_cr("Reserved region:");
566 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
567 p2i(reserved_region().start()),
568 p2i(reserved_region().end()));
569
570 ShenandoahCollectionSet* cset = collection_set();
571 st->print_cr("Collection set:");
572 if (cset != NULL) {
573 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
574 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
575 } else {
576 st->print_cr(" (NULL)");
577 }
578
579 st->cr();
580 MetaspaceUtils::print_on(st);
581
582 if (Verbose) {
583 print_heap_regions_on(st);
584 }
585 }
586
587 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
588 public:
589 void do_thread(Thread* thread) {
590 assert(thread != NULL, "Sanity");
591 assert(thread->is_Worker_thread(), "Only worker thread expected");
592 ShenandoahThreadLocalData::initialize_gclab(thread);
593 }
594 };
595
596 void ShenandoahHeap::post_initialize() {
597 CollectedHeap::post_initialize();
598 MutexLocker ml(Threads_lock);
599
600 ShenandoahInitWorkerGCLABClosure init_gclabs;
601 _workers->threads_do(&init_gclabs);
602
603 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
604 // Now, we will let WorkGang to initialize gclab when new worker is created.
605 _workers->set_initialize_gclab();
606
607 _scm->initialize(_max_workers);
608 _full_gc->initialize(_gc_timer);
609
610 ref_processing_init();
611
612 _heuristics->initialize();
613
614 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
615 }
616
617 size_t ShenandoahHeap::used() const {
618 return Atomic::load_acquire(&_used);
619 }
620
621 size_t ShenandoahHeap::committed() const {
622 OrderAccess::acquire();
623 return _committed;
624 }
625
626 void ShenandoahHeap::increase_committed(size_t bytes) {
627 shenandoah_assert_heaplocked_or_safepoint();
628 _committed += bytes;
629 }
630
631 void ShenandoahHeap::decrease_committed(size_t bytes) {
632 shenandoah_assert_heaplocked_or_safepoint();
633 _committed -= bytes;
634 }
635
636 void ShenandoahHeap::increase_used(size_t bytes) {
637 Atomic::add(&_used, bytes);
638 }
639
640 void ShenandoahHeap::set_used(size_t bytes) {
641 Atomic::release_store_fence(&_used, bytes);
642 }
643
644 void ShenandoahHeap::decrease_used(size_t bytes) {
645 assert(used() >= bytes, "never decrease heap size by more than we've left");
646 Atomic::sub(&_used, bytes);
647 }
648
649 void ShenandoahHeap::increase_allocated(size_t bytes) {
650 Atomic::add(&_bytes_allocated_since_gc_start, bytes);
651 }
652
653 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
654 size_t bytes = words * HeapWordSize;
655 if (!waste) {
656 increase_used(bytes);
657 }
658 increase_allocated(bytes);
659 if (ShenandoahPacing) {
660 control_thread()->pacing_notify_alloc(words);
661 if (waste) {
662 pacer()->claim_for_alloc(words, true);
663 }
664 }
665 }
666
667 size_t ShenandoahHeap::capacity() const {
668 return committed();
669 }
670
671 size_t ShenandoahHeap::max_capacity() const {
672 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
673 }
674
675 size_t ShenandoahHeap::min_capacity() const {
676 return _minimum_size;
677 }
678
679 size_t ShenandoahHeap::initial_capacity() const {
680 return _initial_size;
681 }
682
683 bool ShenandoahHeap::is_in(const void* p) const {
684 HeapWord* heap_base = (HeapWord*) base();
685 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
686 return p >= heap_base && p < last_region_end;
687 }
688
689 void ShenandoahHeap::op_uncommit(double shrink_before) {
690 assert (ShenandoahUncommit, "should be enabled");
691
692 // Application allocates from the beginning of the heap, and GC allocates at
693 // the end of it. It is more efficient to uncommit from the end, so that applications
694 // could enjoy the near committed regions. GC allocations are much less frequent,
695 // and therefore can accept the committing costs.
696
697 size_t count = 0;
698 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
699 ShenandoahHeapRegion* r = get_region(i - 1);
700 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
701 ShenandoahHeapLocker locker(lock());
702 if (r->is_empty_committed()) {
703 // Do not uncommit below minimal capacity
704 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
705 break;
706 }
707
708 r->make_uncommitted();
709 count++;
710 }
711 }
712 SpinPause(); // allow allocators to take the lock
713 }
714
715 if (count > 0) {
716 control_thread()->notify_heap_changed();
717 }
718 }
719
720 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
721 // New object should fit the GCLAB size
722 size_t min_size = MAX2(size, PLAB::min_size());
723
724 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
725 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
726 new_size = MIN2(new_size, PLAB::max_size());
727 new_size = MAX2(new_size, PLAB::min_size());
728
729 // Record new heuristic value even if we take any shortcut. This captures
730 // the case when moderately-sized objects always take a shortcut. At some point,
731 // heuristics should catch up with them.
732 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
733
734 if (new_size < size) {
735 // New size still does not fit the object. Fall back to shared allocation.
736 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
737 return NULL;
738 }
739
740 // Retire current GCLAB, and allocate a new one.
741 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
742 gclab->retire();
743
744 size_t actual_size = 0;
745 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
746 if (gclab_buf == NULL) {
747 return NULL;
748 }
749
750 assert (size <= actual_size, "allocation should fit");
751
752 if (ZeroTLAB) {
753 // ..and clear it.
754 Copy::zero_to_words(gclab_buf, actual_size);
755 } else {
756 // ...and zap just allocated object.
757 #ifdef ASSERT
758 // Skip mangling the space corresponding to the object header to
759 // ensure that the returned space is not considered parsable by
760 // any concurrent GC thread.
761 size_t hdr_size = oopDesc::header_size();
762 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
763 #endif // ASSERT
764 }
765 gclab->set_buf(gclab_buf, actual_size);
766 return gclab->allocate(size);
767 }
768
769 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
770 size_t requested_size,
771 size_t* actual_size) {
772 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
773 HeapWord* res = allocate_memory(req);
774 if (res != NULL) {
775 *actual_size = req.actual_size();
776 } else {
777 *actual_size = 0;
778 }
779 return res;
780 }
781
782 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
783 size_t word_size,
784 size_t* actual_size) {
785 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
786 HeapWord* res = allocate_memory(req);
787 if (res != NULL) {
788 *actual_size = req.actual_size();
789 } else {
790 *actual_size = 0;
791 }
792 return res;
793 }
794
795 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
796 intptr_t pacer_epoch = 0;
797 bool in_new_region = false;
798 HeapWord* result = NULL;
799
800 if (req.is_mutator_alloc()) {
801 if (ShenandoahPacing) {
802 pacer()->pace_for_alloc(req.size());
803 pacer_epoch = pacer()->epoch();
804 }
805
806 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
807 result = allocate_memory_under_lock(req, in_new_region);
808 }
809
810 // Allocation failed, block until control thread reacted, then retry allocation.
811 //
812 // It might happen that one of the threads requesting allocation would unblock
813 // way later after GC happened, only to fail the second allocation, because
814 // other threads have already depleted the free storage. In this case, a better
815 // strategy is to try again, as long as GC makes progress.
816 //
817 // Then, we need to make sure the allocation was retried after at least one
818 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
819
820 size_t tries = 0;
821
822 while (result == NULL && _progress_last_gc.is_set()) {
823 tries++;
824 control_thread()->handle_alloc_failure(req.size());
825 result = allocate_memory_under_lock(req, in_new_region);
826 }
827
828 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
829 tries++;
830 control_thread()->handle_alloc_failure(req.size());
831 result = allocate_memory_under_lock(req, in_new_region);
832 }
833
834 } else {
835 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
836 result = allocate_memory_under_lock(req, in_new_region);
837 // Do not call handle_alloc_failure() here, because we cannot block.
838 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
839 }
840
841 if (in_new_region) {
842 control_thread()->notify_heap_changed();
843 }
844
845 if (result != NULL) {
846 size_t requested = req.size();
847 size_t actual = req.actual_size();
848
849 assert (req.is_lab_alloc() || (requested == actual),
850 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
851 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
852
853 if (req.is_mutator_alloc()) {
854 notify_mutator_alloc_words(actual, false);
855
856 // If we requested more than we were granted, give the rest back to pacer.
857 // This only matters if we are in the same pacing epoch: do not try to unpace
858 // over the budget for the other phase.
859 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
860 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
861 }
862 } else {
863 increase_used(actual*HeapWordSize);
864 }
865 }
866
867 return result;
868 }
869
870 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
871 ShenandoahHeapLocker locker(lock());
872 return _free_set->allocate(req, in_new_region);
873 }
874
875 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
876 bool* gc_overhead_limit_was_exceeded) {
877 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
878 return allocate_memory(req);
879 }
880
881 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
882 size_t size,
883 Metaspace::MetadataType mdtype) {
884 MetaWord* result;
885
886 // Inform metaspace OOM to GC heuristics if class unloading is possible.
887 if (heuristics()->can_unload_classes()) {
888 ShenandoahHeuristics* h = heuristics();
889 h->record_metaspace_oom();
890 }
891
892 // Expand and retry allocation
893 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
894 if (result != NULL) {
895 return result;
896 }
897
898 // Start full GC
899 collect(GCCause::_metadata_GC_clear_soft_refs);
900
901 // Retry allocation
902 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
903 if (result != NULL) {
904 return result;
905 }
906
907 // Expand and retry allocation
908 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
909 if (result != NULL) {
910 return result;
911 }
912
913 // Out of memory
914 return NULL;
915 }
916
917 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
918 private:
919 ShenandoahHeap* const _heap;
920 Thread* const _thread;
921 public:
922 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
923 _heap(heap), _thread(Thread::current()) {}
924
925 void do_object(oop p) {
926 shenandoah_assert_marked(NULL, p);
927 if (!p->is_forwarded()) {
928 _heap->evacuate_object(p, _thread);
929 }
930 }
931 };
932
933 class ShenandoahEvacuationTask : public AbstractGangTask {
934 private:
935 ShenandoahHeap* const _sh;
936 ShenandoahCollectionSet* const _cs;
937 bool _concurrent;
938 public:
939 ShenandoahEvacuationTask(ShenandoahHeap* sh,
940 ShenandoahCollectionSet* cs,
941 bool concurrent) :
942 AbstractGangTask("Parallel Evacuation Task"),
943 _sh(sh),
944 _cs(cs),
945 _concurrent(concurrent)
946 {}
947
948 void work(uint worker_id) {
949 if (_concurrent) {
950 ShenandoahConcurrentWorkerSession worker_session(worker_id);
951 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
952 ShenandoahEvacOOMScope oom_evac_scope;
953 do_work();
954 } else {
955 ShenandoahParallelWorkerSession worker_session(worker_id);
956 ShenandoahEvacOOMScope oom_evac_scope;
957 do_work();
958 }
959 }
960
961 private:
962 void do_work() {
963 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
964 ShenandoahHeapRegion* r;
965 while ((r =_cs->claim_next()) != NULL) {
966 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->index());
967 _sh->marked_object_iterate(r, &cl);
968
969 if (ShenandoahPacing) {
970 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
971 }
972
973 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
974 break;
975 }
976 }
977 }
978 };
979
980 void ShenandoahHeap::trash_cset_regions() {
981 ShenandoahHeapLocker locker(lock());
982
983 ShenandoahCollectionSet* set = collection_set();
984 ShenandoahHeapRegion* r;
985 set->clear_current_index();
986 while ((r = set->next()) != NULL) {
987 r->make_trash();
988 }
989 collection_set()->clear();
990 }
991
992 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
993 st->print_cr("Heap Regions:");
994 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
995 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
996 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark");
997 st->print_cr("SN=alloc sequence number");
998
999 for (size_t i = 0; i < num_regions(); i++) {
1000 get_region(i)->print_on(st);
1001 }
1002 }
1003
1004 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1005 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1006
1007 oop humongous_obj = oop(start->bottom());
1008 size_t size = humongous_obj->size();
1009 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1010 size_t index = start->index() + required_regions - 1;
1011
1012 assert(!start->has_live(), "liveness must be zero");
1013
1014 for(size_t i = 0; i < required_regions; i++) {
1015 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1016 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1017 ShenandoahHeapRegion* region = get_region(index --);
1018
1019 assert(region->is_humongous(), "expect correct humongous start or continuation");
1020 assert(!region->is_cset(), "Humongous region should not be in collection set");
1021
1022 region->make_trash_immediate();
1023 }
1024 }
1025
1026 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1027 public:
1028 void do_thread(Thread* thread) {
1029 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1030 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1031 gclab->retire();
1032 }
1033 };
1034
1035 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1036 if (UseTLAB) {
1037 CollectedHeap::ensure_parsability(retire_tlabs);
1038 }
1039 ShenandoahRetireGCLABClosure cl;
1040 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1041 cl.do_thread(t);
1042 }
1043 workers()->threads_do(&cl);
1044 }
1045
1046 void ShenandoahHeap::resize_tlabs() {
1047 CollectedHeap::resize_all_tlabs();
1048 }
1049
1050 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1051 private:
1052 ShenandoahRootEvacuator* _rp;
1053
1054 public:
1055 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1056 AbstractGangTask("Shenandoah evacuate and update roots"),
1057 _rp(rp) {}
1058
1059 void work(uint worker_id) {
1060 ShenandoahParallelWorkerSession worker_session(worker_id);
1061 ShenandoahEvacOOMScope oom_evac_scope;
1062 ShenandoahEvacuateUpdateRootsClosure<> cl;
1063 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1064 _rp->roots_do(worker_id, &cl);
1065 }
1066 };
1067
1068 void ShenandoahHeap::evacuate_and_update_roots() {
1069 #if COMPILER2_OR_JVMCI
1070 DerivedPointerTable::clear();
1071 #endif
1072 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1073 {
1074 // Include concurrent roots if current cycle can not process those roots concurrently
1075 ShenandoahRootEvacuator rp(workers()->active_workers(),
1076 ShenandoahPhaseTimings::init_evac,
1077 !ShenandoahConcurrentRoots::should_do_concurrent_roots(),
1078 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1079 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1080 workers()->run_task(&roots_task);
1081 }
1082
1083 #if COMPILER2_OR_JVMCI
1084 DerivedPointerTable::update_pointers();
1085 #endif
1086 }
1087
1088 // Returns size in bytes
1089 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1090 if (ShenandoahElasticTLAB) {
1091 // With Elastic TLABs, return the max allowed size, and let the allocation path
1092 // figure out the safe size for current allocation.
1093 return ShenandoahHeapRegion::max_tlab_size_bytes();
1094 } else {
1095 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1096 }
1097 }
1098
1099 size_t ShenandoahHeap::max_tlab_size() const {
1100 // Returns size in words
1101 return ShenandoahHeapRegion::max_tlab_size_words();
1102 }
1103
1104 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1105 public:
1106 void do_thread(Thread* thread) {
1107 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1108 gclab->retire();
1109 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1110 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1111 }
1112 }
1113 };
1114
1115 void ShenandoahHeap::retire_and_reset_gclabs() {
1116 ShenandoahRetireAndResetGCLABClosure cl;
1117 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1118 cl.do_thread(t);
1119 }
1120 workers()->threads_do(&cl);
1121 }
1122
1123 void ShenandoahHeap::collect(GCCause::Cause cause) {
1124 control_thread()->request_gc(cause);
1125 }
1126
1127 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1128 //assert(false, "Shouldn't need to do full collections");
1129 }
1130
1131 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1132 ShenandoahHeapRegion* r = heap_region_containing(addr);
1133 if (r != NULL) {
1134 return r->block_start(addr);
1135 }
1136 return NULL;
1137 }
1138
1139 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1140 ShenandoahHeapRegion* r = heap_region_containing(addr);
1141 return r->block_is_obj(addr);
1142 }
1143
1144 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const {
1145 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr);
1146 }
1147
1148 jlong ShenandoahHeap::millis_since_last_gc() {
1149 double v = heuristics()->time_since_last_gc() * 1000;
1150 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1151 return (jlong)v;
1152 }
1153
1154 void ShenandoahHeap::prepare_for_verify() {
1155 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1156 make_parsable(false);
1157 }
1158 }
1159
1160 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1161 workers()->print_worker_threads_on(st);
1162 if (ShenandoahStringDedup::is_enabled()) {
1163 ShenandoahStringDedup::print_worker_threads_on(st);
1164 }
1165 }
1166
1167 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1168 workers()->threads_do(tcl);
1169 if (_safepoint_workers != NULL) {
1170 _safepoint_workers->threads_do(tcl);
1171 }
1172 if (ShenandoahStringDedup::is_enabled()) {
1173 ShenandoahStringDedup::threads_do(tcl);
1174 }
1175 }
1176
1177 void ShenandoahHeap::print_tracing_info() const {
1178 LogTarget(Info, gc, stats) lt;
1179 if (lt.is_enabled()) {
1180 ResourceMark rm;
1181 LogStream ls(lt);
1182
1183 phase_timings()->print_on(&ls);
1184
1185 ls.cr();
1186 ls.cr();
1187
1188 shenandoah_policy()->print_gc_stats(&ls);
1189
1190 ls.cr();
1191 ls.cr();
1192
1193 if (ShenandoahPacing) {
1194 pacer()->print_on(&ls);
1195 }
1196
1197 ls.cr();
1198 ls.cr();
1199 }
1200 }
1201
1202 void ShenandoahHeap::verify(VerifyOption vo) {
1203 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1204 if (ShenandoahVerify) {
1205 verifier()->verify_generic(vo);
1206 } else {
1207 // TODO: Consider allocating verification bitmaps on demand,
1208 // and turn this on unconditionally.
1209 }
1210 }
1211 }
1212 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1213 return _free_set->capacity();
1214 }
1215
1216 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1217 private:
1218 MarkBitMap* _bitmap;
1219 Stack<oop,mtGC>* _oop_stack;
1220 ShenandoahHeap* const _heap;
1221 ShenandoahMarkingContext* const _marking_context;
1222
1223 template <class T>
1224 void do_oop_work(T* p) {
1225 T o = RawAccess<>::oop_load(p);
1226 if (!CompressedOops::is_null(o)) {
1227 oop obj = CompressedOops::decode_not_null(o);
1228 if (_heap->is_concurrent_root_in_progress() && !_marking_context->is_marked(obj)) {
1229 // There may be dead oops in weak roots in concurrent root phase, do not touch them.
1230 return;
1231 }
1232 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1233
1234 assert(oopDesc::is_oop(obj), "must be a valid oop");
1235 if (!_bitmap->is_marked(obj)) {
1236 _bitmap->mark(obj);
1237 _oop_stack->push(obj);
1238 }
1239 }
1240 }
1241 public:
1242 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1243 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()),
1244 _marking_context(_heap->marking_context()) {}
1245 void do_oop(oop* p) { do_oop_work(p); }
1246 void do_oop(narrowOop* p) { do_oop_work(p); }
1247 };
1248
1249 /*
1250 * This is public API, used in preparation of object_iterate().
1251 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1252 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1253 * control, we call SH::make_tlabs_parsable().
1254 */
1255 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1256 // No-op.
1257 }
1258
1259 /*
1260 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1261 *
1262 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1263 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1264 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1265 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1266 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1267 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1268 * wiped the bitmap in preparation for next marking).
1269 *
1270 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1271 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1272 * is allowed to report dead objects, but is not required to do so.
1273 */
1274 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1275 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1276 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1277 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1278 return;
1279 }
1280
1281 // Reset bitmap
1282 _aux_bit_map.clear();
1283
1284 Stack<oop,mtGC> oop_stack;
1285
1286 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects.
1287 ShenandoahHeapIterationRootScanner rp;
1288 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1289
1290 rp.roots_do(&oops);
1291
1292 // Work through the oop stack to traverse heap.
1293 while (! oop_stack.is_empty()) {
1294 oop obj = oop_stack.pop();
1295 assert(oopDesc::is_oop(obj), "must be a valid oop");
1296 cl->do_object(obj);
1297 obj->oop_iterate(&oops);
1298 }
1299
1300 assert(oop_stack.is_empty(), "should be empty");
1301
1302 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1303 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1304 }
1305 }
1306
1307 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1308 void ShenandoahHeap::keep_alive(oop obj) {
1309 if (is_concurrent_mark_in_progress()) {
1310 ShenandoahBarrierSet::barrier_set()->enqueue(obj);
1311 }
1312 }
1313
1314 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1315 for (size_t i = 0; i < num_regions(); i++) {
1316 ShenandoahHeapRegion* current = get_region(i);
1317 blk->heap_region_do(current);
1318 }
1319 }
1320
1321 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1322 private:
1323 ShenandoahHeap* const _heap;
1324 ShenandoahHeapRegionClosure* const _blk;
1325
1326 shenandoah_padding(0);
1327 volatile size_t _index;
1328 shenandoah_padding(1);
1329
1330 public:
1331 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1332 AbstractGangTask("Parallel Region Task"),
1333 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1334
1335 void work(uint worker_id) {
1336 size_t stride = ShenandoahParallelRegionStride;
1337
1338 size_t max = _heap->num_regions();
1339 while (_index < max) {
1340 size_t cur = Atomic::fetch_and_add(&_index, stride);
1341 size_t start = cur;
1342 size_t end = MIN2(cur + stride, max);
1343 if (start >= max) break;
1344
1345 for (size_t i = cur; i < end; i++) {
1346 ShenandoahHeapRegion* current = _heap->get_region(i);
1347 _blk->heap_region_do(current);
1348 }
1349 }
1350 }
1351 };
1352
1353 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1354 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1355 if (num_regions() > ShenandoahParallelRegionStride) {
1356 ShenandoahParallelHeapRegionTask task(blk);
1357 workers()->run_task(&task);
1358 } else {
1359 heap_region_iterate(blk);
1360 }
1361 }
1362
1363 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1364 private:
1365 ShenandoahMarkingContext* const _ctx;
1366 public:
1367 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1368
1369 void heap_region_do(ShenandoahHeapRegion* r) {
1370 if (r->is_active()) {
1371 r->clear_live_data();
1372 _ctx->capture_top_at_mark_start(r);
1373 } else {
1374 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
1375 assert(_ctx->top_at_mark_start(r) == r->top(),
1376 "Region " SIZE_FORMAT " should already have correct TAMS", r->index());
1377 }
1378 }
1379
1380 bool is_thread_safe() { return true; }
1381 };
1382
1383 void ShenandoahHeap::op_init_mark() {
1384 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1385 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1386
1387 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1388 assert(!marking_context()->is_complete(), "should not be complete");
1389 assert(!has_forwarded_objects(), "No forwarded objects on this path");
1390
1391 if (ShenandoahVerify) {
1392 verifier()->verify_before_concmark();
1393 }
1394
1395 if (VerifyBeforeGC) {
1396 Universe::verify();
1397 }
1398
1399 set_concurrent_mark_in_progress(true);
1400 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1401 {
1402 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1403 make_parsable(true);
1404 }
1405
1406 {
1407 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1408 ShenandoahClearLivenessClosure clc;
1409 parallel_heap_region_iterate(&clc);
1410 }
1411
1412 // Make above changes visible to worker threads
1413 OrderAccess::fence();
1414
1415 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1416
1417 if (UseTLAB) {
1418 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1419 resize_tlabs();
1420 }
1421
1422 if (ShenandoahPacing) {
1423 pacer()->setup_for_mark();
1424 }
1425
1426 // Arm nmethods for concurrent marking. When a nmethod is about to be executed,
1427 // we need to make sure that all its metadata are marked. alternative is to remark
1428 // thread roots at final mark pause, but it can be potential latency killer.
1429 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1430 ShenandoahCodeRoots::arm_nmethods();
1431 }
1432 }
1433
1434 void ShenandoahHeap::op_mark() {
1435 concurrent_mark()->mark_from_roots();
1436 }
1437
1438 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1439 private:
1440 ShenandoahMarkingContext* const _ctx;
1441 public:
1442 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1443
1444 void heap_region_do(ShenandoahHeapRegion* r) {
1445 if (r->is_active()) {
1446 HeapWord *tams = _ctx->top_at_mark_start(r);
1447 HeapWord *top = r->top();
1448 if (top > tams) {
1449 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1450 }
1451 } else {
1452 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
1453 assert(_ctx->top_at_mark_start(r) == r->top(),
1454 "Region " SIZE_FORMAT " should have correct TAMS", r->index());
1455 }
1456 }
1457
1458 bool is_thread_safe() { return true; }
1459 };
1460
1461 void ShenandoahHeap::op_final_mark() {
1462 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1463 assert(!has_forwarded_objects(), "No forwarded objects on this path");
1464
1465 // It is critical that we
1466 // evacuate roots right after finishing marking, so that we don't
1467 // get unmarked objects in the roots.
1468
1469 if (!cancelled_gc()) {
1470 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1471
1472 // Marking is completed, deactivate SATB barrier
1473 set_concurrent_mark_in_progress(false);
1474 mark_complete_marking_context();
1475
1476 parallel_cleaning(false /* full gc*/);
1477
1478 if (ShenandoahVerify) {
1479 verifier()->verify_roots_no_forwarded();
1480 }
1481 // All allocations past TAMS are implicitly live, adjust the region data.
1482 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1483 {
1484 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1485 ShenandoahCompleteLivenessClosure cl;
1486 parallel_heap_region_iterate(&cl);
1487 }
1488
1489 // Force the threads to reacquire their TLABs outside the collection set.
1490 {
1491 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs);
1492 make_parsable(true);
1493 }
1494
1495 // We are about to select the collection set, make sure it knows about
1496 // current pinning status. Also, this allows trashing more regions that
1497 // now have their pinning status dropped.
1498 {
1499 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned);
1500 sync_pinned_region_status();
1501 }
1502
1503 {
1504 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac);
1505
1506 ShenandoahHeapLocker locker(lock());
1507 _collection_set->clear();
1508 _free_set->clear();
1509
1510 heuristics()->choose_collection_set(_collection_set);
1511
1512 _free_set->rebuild();
1513 }
1514
1515 if (!is_degenerated_gc_in_progress()) {
1516 prepare_concurrent_roots();
1517 prepare_concurrent_unloading();
1518 }
1519
1520 // If collection set has candidates, start evacuation.
1521 // Otherwise, bypass the rest of the cycle.
1522 if (!collection_set()->is_empty()) {
1523 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1524
1525 if (ShenandoahVerify) {
1526 verifier()->verify_before_evacuation();
1527 }
1528
1529 // Remember limit for updating refs. It's guaranteed that we get no from-space-refs written
1530 // from here on.
1531 for (uint i = 0; i < num_regions(); i++) {
1532 ShenandoahHeapRegion* r = get_region(i);
1533 r->set_update_watermark(r->top());
1534 }
1535
1536 set_evacuation_in_progress(true);
1537 // From here on, we need to update references.
1538 set_has_forwarded_objects(true);
1539
1540 if (!is_degenerated_gc_in_progress()) {
1541 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1542 ShenandoahCodeRoots::arm_nmethods();
1543 }
1544 evacuate_and_update_roots();
1545 }
1546
1547 if (ShenandoahPacing) {
1548 pacer()->setup_for_evac();
1549 }
1550
1551 if (ShenandoahVerify) {
1552 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None;
1553 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1554 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots);
1555 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots);
1556 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots);
1557 }
1558
1559 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1560 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots);
1561 }
1562 verifier()->verify_roots_no_forwarded_except(types);
1563 verifier()->verify_during_evacuation();
1564 }
1565 } else {
1566 if (ShenandoahVerify) {
1567 verifier()->verify_after_concmark();
1568 }
1569
1570 if (VerifyAfterGC) {
1571 Universe::verify();
1572 }
1573 }
1574
1575 } else {
1576 // If this cycle was updating references, we need to keep the has_forwarded_objects
1577 // flag on, for subsequent phases to deal with it.
1578 concurrent_mark()->cancel();
1579 set_concurrent_mark_in_progress(false);
1580
1581 if (process_references()) {
1582 // Abandon reference processing right away: pre-cleaning must have failed.
1583 ReferenceProcessor *rp = ref_processor();
1584 rp->disable_discovery();
1585 rp->abandon_partial_discovery();
1586 rp->verify_no_references_recorded();
1587 }
1588 }
1589 }
1590
1591 void ShenandoahHeap::op_conc_evac() {
1592 ShenandoahEvacuationTask task(this, _collection_set, true);
1593 workers()->run_task(&task);
1594 }
1595
1596 void ShenandoahHeap::op_stw_evac() {
1597 ShenandoahEvacuationTask task(this, _collection_set, false);
1598 workers()->run_task(&task);
1599 }
1600
1601 void ShenandoahHeap::op_updaterefs() {
1602 update_heap_references(true);
1603 }
1604
1605 void ShenandoahHeap::op_cleanup() {
1606 free_set()->recycle_trash();
1607 }
1608
1609 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask {
1610 private:
1611 ShenandoahVMRoots<true /*concurrent*/> _vm_roots;
1612 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots;
1613 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots;
1614 ShenandoahConcurrentStringDedupRoots _dedup_roots;
1615 bool _include_weak_roots;
1616
1617 public:
1618 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) :
1619 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"),
1620 _include_weak_roots(include_weak_roots) {
1621 }
1622
1623 void work(uint worker_id) {
1624 ShenandoahEvacOOMScope oom;
1625 {
1626 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration
1627 // may race against OopStorage::release() calls.
1628 ShenandoahEvacUpdateOopStorageRootsClosure cl;
1629 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1630
1631 if (_include_weak_roots) {
1632 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1633 }
1634 }
1635
1636 {
1637 ShenandoahEvacuateUpdateRootsClosure<> cl;
1638 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
1639 _cld_roots.cld_do(&clds);
1640 }
1641
1642 {
1643 ShenandoahForwardedIsAliveClosure is_alive;
1644 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive;
1645 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id);
1646 }
1647 }
1648 };
1649
1650 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure {
1651 private:
1652 ShenandoahHeap* const _heap;
1653 ShenandoahMarkingContext* const _mark_context;
1654 bool _evac_in_progress;
1655 Thread* const _thread;
1656 size_t _dead_counter;
1657
1658 public:
1659 ShenandoahEvacUpdateCleanupOopStorageRootsClosure();
1660 void do_oop(oop* p);
1661 void do_oop(narrowOop* p);
1662
1663 size_t dead_counter() const;
1664 void reset_dead_counter();
1665 };
1666
1667 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() :
1668 _heap(ShenandoahHeap::heap()),
1669 _mark_context(ShenandoahHeap::heap()->marking_context()),
1670 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()),
1671 _thread(Thread::current()),
1672 _dead_counter(0) {
1673 }
1674
1675 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) {
1676 const oop obj = RawAccess<>::oop_load(p);
1677 if (!CompressedOops::is_null(obj)) {
1678 if (!_mark_context->is_marked(obj)) {
1679 shenandoah_assert_correct(p, obj);
1680 oop old = Atomic::cmpxchg(p, obj, oop(NULL));
1681 if (obj == old) {
1682 _dead_counter ++;
1683 }
1684 } else if (_evac_in_progress && _heap->in_collection_set(obj)) {
1685 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1686 if (resolved == obj) {
1687 resolved = _heap->evacuate_object(obj, _thread);
1688 }
1689 Atomic::cmpxchg(p, obj, resolved);
1690 assert(_heap->cancelled_gc() ||
1691 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved),
1692 "Sanity");
1693 }
1694 }
1695 }
1696
1697 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) {
1698 ShouldNotReachHere();
1699 }
1700
1701 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const {
1702 return _dead_counter;
1703 }
1704
1705 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() {
1706 _dead_counter = 0;
1707 }
1708
1709 // This task not only evacuates/updates marked weak roots, but also "NULL"
1710 // dead weak roots.
1711 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask {
1712 private:
1713 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots;
1714 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots;
1715 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots;
1716 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots;
1717
1718 public:
1719 ShenandoahConcurrentWeakRootsEvacUpdateTask() :
1720 AbstractGangTask("Shenandoah Concurrent Weak Root Task"),
1721 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots),
1722 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots),
1723 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots),
1724 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) {
1725 StringTable::reset_dead_counter();
1726 ResolvedMethodTable::reset_dead_counter();
1727 }
1728
1729 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() {
1730 StringTable::finish_dead_counter();
1731 ResolvedMethodTable::finish_dead_counter();
1732 }
1733
1734 void work(uint worker_id) {
1735 ShenandoahEvacOOMScope oom;
1736 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration
1737 // may race against OopStorage::release() calls.
1738 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl;
1739 _jni_roots.oops_do(&cl, worker_id);
1740 _vm_roots.oops_do(&cl, worker_id);
1741
1742 cl.reset_dead_counter();
1743 _string_table_roots.oops_do(&cl, worker_id);
1744 StringTable::inc_dead_counter(cl.dead_counter());
1745
1746 cl.reset_dead_counter();
1747 _resolved_method_table_roots.oops_do(&cl, worker_id);
1748 ResolvedMethodTable::inc_dead_counter(cl.dead_counter());
1749 }
1750 };
1751
1752 void ShenandoahHeap::op_roots() {
1753 if (is_concurrent_root_in_progress()) {
1754 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1755 // Concurrent weak root processing
1756 ShenandoahConcurrentWeakRootsEvacUpdateTask task;
1757 workers()->run_task(&task);
1758
1759 _unloader.unload();
1760 }
1761
1762 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1763 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1764 workers()->run_task(&task);
1765 }
1766 }
1767
1768 set_concurrent_root_in_progress(false);
1769 }
1770
1771 void ShenandoahHeap::op_reset() {
1772 if (ShenandoahPacing) {
1773 pacer()->setup_for_reset();
1774 }
1775 reset_mark_bitmap();
1776 }
1777
1778 void ShenandoahHeap::op_preclean() {
1779 if (ShenandoahPacing) {
1780 pacer()->setup_for_preclean();
1781 }
1782 concurrent_mark()->preclean_weak_refs();
1783 }
1784
1785 void ShenandoahHeap::op_init_traversal() {
1786 traversal_gc()->init_traversal_collection();
1787 }
1788
1789 void ShenandoahHeap::op_traversal() {
1790 traversal_gc()->concurrent_traversal_collection();
1791 }
1792
1793 void ShenandoahHeap::op_final_traversal() {
1794 traversal_gc()->final_traversal_collection();
1795 }
1796
1797 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1798 ShenandoahMetricsSnapshot metrics;
1799 metrics.snap_before();
1800
1801 full_gc()->do_it(cause);
1802 if (UseTLAB) {
1803 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1804 resize_all_tlabs();
1805 }
1806
1807 metrics.snap_after();
1808
1809 if (metrics.is_good_progress()) {
1810 _progress_last_gc.set();
1811 } else {
1812 // Nothing to do. Tell the allocation path that we have failed to make
1813 // progress, and it can finally fail.
1814 _progress_last_gc.unset();
1815 }
1816 }
1817
1818 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1819 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1820 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1821 // some phase, we have to upgrade the Degenerate GC to Full GC.
1822
1823 clear_cancelled_gc();
1824
1825 ShenandoahMetricsSnapshot metrics;
1826 metrics.snap_before();
1827
1828 switch (point) {
1829 case _degenerated_traversal:
1830 {
1831 // Drop the collection set. Note: this leaves some already forwarded objects
1832 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1833 // workarounds in ShenandoahTraversalHeuristics.
1834
1835 ShenandoahHeapLocker locker(lock());
1836 collection_set()->clear_current_index();
1837 for (size_t i = 0; i < collection_set()->count(); i++) {
1838 ShenandoahHeapRegion* r = collection_set()->next();
1839 r->make_regular_bypass();
1840 }
1841 collection_set()->clear();
1842 }
1843 op_final_traversal();
1844 op_cleanup();
1845 return;
1846
1847 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1848 // but enters it at different points, depending on which concurrent phase had
1849 // degenerated.
1850
1851 case _degenerated_outside_cycle:
1852 // We have degenerated from outside the cycle, which means something is bad with
1853 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1854 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1855 // we can do the most aggressive degen cycle, which includes processing references and
1856 // class unloading, unless those features are explicitly disabled.
1857 //
1858 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1859 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1860 set_process_references(heuristics()->can_process_references());
1861 set_unload_classes(heuristics()->can_unload_classes());
1862
1863 if (is_traversal_mode()) {
1864 // Not possible to degenerate from here, upgrade to Full GC right away.
1865 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1866 op_degenerated_fail();
1867 return;
1868 }
1869
1870 op_reset();
1871
1872 op_init_mark();
1873 if (cancelled_gc()) {
1874 op_degenerated_fail();
1875 return;
1876 }
1877
1878 case _degenerated_mark:
1879 op_final_mark();
1880 if (cancelled_gc()) {
1881 op_degenerated_fail();
1882 return;
1883 }
1884
1885 if (!has_forwarded_objects() && ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) {
1886 // Disarm nmethods that armed for concurrent mark. On normal cycle, it would
1887 // be disarmed while conc-roots phase is running.
1888 // TODO: Call op_conc_roots() here instead
1889 ShenandoahCodeRoots::disarm_nmethods();
1890 }
1891
1892 op_cleanup();
1893
1894 case _degenerated_evac:
1895 // If heuristics thinks we should do the cycle, this flag would be set,
1896 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1897 if (is_evacuation_in_progress()) {
1898
1899 // Degeneration under oom-evac protocol might have left some objects in
1900 // collection set un-evacuated. Restart evacuation from the beginning to
1901 // capture all objects. For all the objects that are already evacuated,
1902 // it would be a simple check, which is supposed to be fast. This is also
1903 // safe to do even without degeneration, as CSet iterator is at beginning
1904 // in preparation for evacuation anyway.
1905 //
1906 // Before doing that, we need to make sure we never had any cset-pinned
1907 // regions. This may happen if allocation failure happened when evacuating
1908 // the about-to-be-pinned object, oom-evac protocol left the object in
1909 // the collection set, and then the pin reached the cset region. If we continue
1910 // the cycle here, we would trash the cset and alive objects in it. To avoid
1911 // it, we fail degeneration right away and slide into Full GC to recover.
1912
1913 {
1914 sync_pinned_region_status();
1915 collection_set()->clear_current_index();
1916
1917 ShenandoahHeapRegion* r;
1918 while ((r = collection_set()->next()) != NULL) {
1919 if (r->is_pinned()) {
1920 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1921 op_degenerated_fail();
1922 return;
1923 }
1924 }
1925
1926 collection_set()->clear_current_index();
1927 }
1928
1929 op_stw_evac();
1930 if (cancelled_gc()) {
1931 op_degenerated_fail();
1932 return;
1933 }
1934 }
1935
1936 // If heuristics thinks we should do the cycle, this flag would be set,
1937 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1938 if (has_forwarded_objects()) {
1939 op_init_updaterefs();
1940 if (cancelled_gc()) {
1941 op_degenerated_fail();
1942 return;
1943 }
1944 }
1945
1946 case _degenerated_updaterefs:
1947 if (has_forwarded_objects()) {
1948 op_final_updaterefs();
1949 if (cancelled_gc()) {
1950 op_degenerated_fail();
1951 return;
1952 }
1953 }
1954
1955 op_cleanup();
1956 break;
1957
1958 default:
1959 ShouldNotReachHere();
1960 }
1961
1962 if (ShenandoahVerify) {
1963 verifier()->verify_after_degenerated();
1964 }
1965
1966 if (VerifyAfterGC) {
1967 Universe::verify();
1968 }
1969
1970 metrics.snap_after();
1971
1972 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1973 // because that probably means the heap is overloaded and/or fragmented.
1974 if (!metrics.is_good_progress()) {
1975 _progress_last_gc.unset();
1976 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1977 op_degenerated_futile();
1978 } else {
1979 _progress_last_gc.set();
1980 }
1981 }
1982
1983 void ShenandoahHeap::op_degenerated_fail() {
1984 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1985 shenandoah_policy()->record_degenerated_upgrade_to_full();
1986 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1987 }
1988
1989 void ShenandoahHeap::op_degenerated_futile() {
1990 shenandoah_policy()->record_degenerated_upgrade_to_full();
1991 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1992 }
1993
1994 void ShenandoahHeap::force_satb_flush_all_threads() {
1995 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1996 // No need to flush SATBs
1997 return;
1998 }
1999
2000 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2001 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
2002 }
2003 // The threads are not "acquiring" their thread-local data, but it does not
2004 // hurt to "release" the updates here anyway.
2005 OrderAccess::fence();
2006 }
2007
2008 void ShenandoahHeap::set_gc_state_all_threads(char state) {
2009 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2010 ShenandoahThreadLocalData::set_gc_state(t, state);
2011 }
2012 }
2013
2014 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
2015 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
2016 _gc_state.set_cond(mask, value);
2017 set_gc_state_all_threads(_gc_state.raw_value());
2018 }
2019
2020 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
2021 if (has_forwarded_objects()) {
2022 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
2023 } else {
2024 set_gc_state_mask(MARKING, in_progress);
2025 }
2026 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2027 }
2028
2029 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
2030 set_gc_state_mask(TRAVERSAL, in_progress);
2031 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2032 }
2033
2034 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2035 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
2036 set_gc_state_mask(EVACUATION, in_progress);
2037 }
2038
2039 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) {
2040 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?");
2041 if (in_progress) {
2042 _concurrent_root_in_progress.set();
2043 } else {
2044 _concurrent_root_in_progress.unset();
2045 }
2046 }
2047
2048 void ShenandoahHeap::ref_processing_init() {
2049 assert(_max_workers > 0, "Sanity");
2050
2051 _ref_processor =
2052 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2053 ParallelRefProcEnabled, // MT processing
2054 _max_workers, // Degree of MT processing
2055 true, // MT discovery
2056 _max_workers, // Degree of MT discovery
2057 false, // Reference discovery is not atomic
2058 NULL, // No closure, should be installed before use
2059 true); // Scale worker threads
2060
2061 shenandoah_assert_rp_isalive_not_installed();
2062 }
2063
2064 GCTracer* ShenandoahHeap::tracer() {
2065 return shenandoah_policy()->tracer();
2066 }
2067
2068 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2069 return _free_set->used();
2070 }
2071
2072 bool ShenandoahHeap::try_cancel_gc() {
2073 while (true) {
2074 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
2075 if (prev == CANCELLABLE) return true;
2076 else if (prev == CANCELLED) return false;
2077 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
2078 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
2079 if (Thread::current()->is_Java_thread()) {
2080 // We need to provide a safepoint here, otherwise we might
2081 // spin forever if a SP is pending.
2082 ThreadBlockInVM sp(JavaThread::current());
2083 SpinPause();
2084 }
2085 }
2086 }
2087
2088 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2089 if (try_cancel_gc()) {
2090 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2091 log_info(gc)("%s", msg.buffer());
2092 Events::log(Thread::current(), "%s", msg.buffer());
2093 }
2094 }
2095
2096 uint ShenandoahHeap::max_workers() {
2097 return _max_workers;
2098 }
2099
2100 void ShenandoahHeap::stop() {
2101 // The shutdown sequence should be able to terminate when GC is running.
2102
2103 // Step 0. Notify policy to disable event recording.
2104 _shenandoah_policy->record_shutdown();
2105
2106 // Step 1. Notify control thread that we are in shutdown.
2107 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2108 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2109 control_thread()->prepare_for_graceful_shutdown();
2110
2111 // Step 2. Notify GC workers that we are cancelling GC.
2112 cancel_gc(GCCause::_shenandoah_stop_vm);
2113
2114 // Step 3. Wait until GC worker exits normally.
2115 control_thread()->stop();
2116
2117 // Step 4. Stop String Dedup thread if it is active
2118 if (ShenandoahStringDedup::is_enabled()) {
2119 ShenandoahStringDedup::stop();
2120 }
2121 }
2122
2123 void ShenandoahHeap::stw_unload_classes(bool full_gc) {
2124 if (!unload_classes()) return;
2125 bool purged_class;
2126
2127 // Unload classes and purge SystemDictionary.
2128 {
2129 ShenandoahGCPhase phase(full_gc ?
2130 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2131 ShenandoahPhaseTimings::purge_class_unload);
2132 purged_class = SystemDictionary::do_unloading(gc_timer());
2133 }
2134
2135 {
2136 ShenandoahGCPhase phase(full_gc ?
2137 ShenandoahPhaseTimings::full_gc_purge_par :
2138 ShenandoahPhaseTimings::purge_par);
2139 ShenandoahIsAliveSelector is_alive;
2140 uint num_workers = _workers->active_workers();
2141 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class);
2142 _workers->run_task(&unlink_task);
2143 }
2144
2145 {
2146 ShenandoahGCPhase phase(full_gc ?
2147 ShenandoahPhaseTimings::full_gc_purge_cldg :
2148 ShenandoahPhaseTimings::purge_cldg);
2149 ClassLoaderDataGraph::purge();
2150 }
2151 // Resize and verify metaspace
2152 MetaspaceGC::compute_new_size();
2153 MetaspaceUtils::verify_metrics();
2154 }
2155
2156 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs),
2157 // so they should not have forwarded oops.
2158 // However, we do need to "null" dead oops in the roots, if can not be done
2159 // in concurrent cycles.
2160 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) {
2161 ShenandoahGCPhase root_phase(full_gc ?
2162 ShenandoahPhaseTimings::full_gc_purge :
2163 ShenandoahPhaseTimings::purge);
2164 uint num_workers = _workers->active_workers();
2165 ShenandoahPhaseTimings::Phase timing_phase = full_gc ?
2166 ShenandoahPhaseTimings::full_gc_purge_par :
2167 ShenandoahPhaseTimings::purge_par;
2168 ShenandoahGCPhase phase(timing_phase);
2169 ShenandoahGCWorkerPhase worker_phase(timing_phase);
2170
2171 // Cleanup weak roots
2172 if (has_forwarded_objects()) {
2173 ShenandoahForwardedIsAliveClosure is_alive;
2174 ShenandoahUpdateRefsClosure keep_alive;
2175 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
2176 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2177 _workers->run_task(&cleaning_task);
2178 } else {
2179 ShenandoahIsAliveClosure is_alive;
2180 #ifdef ASSERT
2181 ShenandoahAssertNotForwardedClosure verify_cl;
2182 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure>
2183 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2184 #else
2185 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure>
2186 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2187 #endif
2188 _workers->run_task(&cleaning_task);
2189 }
2190 }
2191
2192 void ShenandoahHeap::parallel_cleaning(bool full_gc) {
2193 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2194 stw_process_weak_roots(full_gc);
2195 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2196 stw_unload_classes(full_gc);
2197 }
2198 }
2199
2200 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2201 if (is_traversal_mode()) {
2202 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond);
2203 } else {
2204 set_gc_state_mask(HAS_FORWARDED, cond);
2205 }
2206
2207 }
2208
2209 void ShenandoahHeap::set_process_references(bool pr) {
2210 _process_references.set_cond(pr);
2211 }
2212
2213 void ShenandoahHeap::set_unload_classes(bool uc) {
2214 _unload_classes.set_cond(uc);
2215 }
2216
2217 bool ShenandoahHeap::process_references() const {
2218 return _process_references.is_set();
2219 }
2220
2221 bool ShenandoahHeap::unload_classes() const {
2222 return _unload_classes.is_set();
2223 }
2224
2225 address ShenandoahHeap::in_cset_fast_test_addr() {
2226 ShenandoahHeap* heap = ShenandoahHeap::heap();
2227 assert(heap->collection_set() != NULL, "Sanity");
2228 return (address) heap->collection_set()->biased_map_address();
2229 }
2230
2231 address ShenandoahHeap::cancelled_gc_addr() {
2232 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2233 }
2234
2235 address ShenandoahHeap::gc_state_addr() {
2236 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2237 }
2238
2239 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2240 return Atomic::load_acquire(&_bytes_allocated_since_gc_start);
2241 }
2242
2243 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2244 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2245 }
2246
2247 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2248 _degenerated_gc_in_progress.set_cond(in_progress);
2249 }
2250
2251 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2252 _full_gc_in_progress.set_cond(in_progress);
2253 }
2254
2255 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2256 assert (is_full_gc_in_progress(), "should be");
2257 _full_gc_move_in_progress.set_cond(in_progress);
2258 }
2259
2260 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2261 set_gc_state_mask(UPDATEREFS, in_progress);
2262 }
2263
2264 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2265 ShenandoahCodeRoots::register_nmethod(nm);
2266 }
2267
2268 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2269 ShenandoahCodeRoots::unregister_nmethod(nm);
2270 }
2271
2272 void ShenandoahHeap::flush_nmethod(nmethod* nm) {
2273 ShenandoahCodeRoots::flush_nmethod(nm);
2274 }
2275
2276 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2277 heap_region_containing(o)->record_pin();
2278 return o;
2279 }
2280
2281 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2282 heap_region_containing(o)->record_unpin();
2283 }
2284
2285 void ShenandoahHeap::sync_pinned_region_status() {
2286 ShenandoahHeapLocker locker(lock());
2287
2288 for (size_t i = 0; i < num_regions(); i++) {
2289 ShenandoahHeapRegion *r = get_region(i);
2290 if (r->is_active()) {
2291 if (r->is_pinned()) {
2292 if (r->pin_count() == 0) {
2293 r->make_unpinned();
2294 }
2295 } else {
2296 if (r->pin_count() > 0) {
2297 r->make_pinned();
2298 }
2299 }
2300 }
2301 }
2302
2303 assert_pinned_region_status();
2304 }
2305
2306 #ifdef ASSERT
2307 void ShenandoahHeap::assert_pinned_region_status() {
2308 for (size_t i = 0; i < num_regions(); i++) {
2309 ShenandoahHeapRegion* r = get_region(i);
2310 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0),
2311 "Region " SIZE_FORMAT " pinning status is inconsistent", i);
2312 }
2313 }
2314 #endif
2315
2316 GCTimer* ShenandoahHeap::gc_timer() const {
2317 return _gc_timer;
2318 }
2319
2320 void ShenandoahHeap::prepare_concurrent_roots() {
2321 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2322 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
2323 set_concurrent_root_in_progress(true);
2324 }
2325 }
2326
2327 void ShenandoahHeap::prepare_concurrent_unloading() {
2328 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2329 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2330 _unloader.prepare();
2331 }
2332 }
2333
2334 void ShenandoahHeap::finish_concurrent_unloading() {
2335 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2336 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2337 _unloader.finish();
2338 }
2339 }
2340
2341 #ifdef ASSERT
2342 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2343 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2344
2345 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2346 if (UseDynamicNumberOfGCThreads) {
2347 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2348 } else {
2349 // Use ParallelGCThreads inside safepoints
2350 assert(nworkers == ParallelGCThreads, "Use ParallelGCThreads within safepoints");
2351 }
2352 } else {
2353 if (UseDynamicNumberOfGCThreads) {
2354 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2355 } else {
2356 // Use ConcGCThreads outside safepoints
2357 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2358 }
2359 }
2360 }
2361 #endif
2362
2363 ShenandoahVerifier* ShenandoahHeap::verifier() {
2364 guarantee(ShenandoahVerify, "Should be enabled");
2365 assert (_verifier != NULL, "sanity");
2366 return _verifier;
2367 }
2368
2369 template<class T>
2370 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2371 private:
2372 T cl;
2373 ShenandoahHeap* _heap;
2374 ShenandoahRegionIterator* _regions;
2375 bool _concurrent;
2376 public:
2377 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2378 AbstractGangTask("Concurrent Update References Task"),
2379 cl(T()),
2380 _heap(ShenandoahHeap::heap()),
2381 _regions(regions),
2382 _concurrent(concurrent) {
2383 }
2384
2385 void work(uint worker_id) {
2386 if (_concurrent) {
2387 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2388 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2389 do_work();
2390 } else {
2391 ShenandoahParallelWorkerSession worker_session(worker_id);
2392 do_work();
2393 }
2394 }
2395
2396 private:
2397 void do_work() {
2398 ShenandoahHeapRegion* r = _regions->next();
2399 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2400 while (r != NULL) {
2401 HeapWord* update_watermark = r->get_update_watermark();
2402 assert (update_watermark >= r->bottom(), "sanity");
2403 if (r->is_active() && !r->is_cset()) {
2404 _heap->marked_object_oop_iterate(r, &cl, update_watermark);
2405 }
2406 if (ShenandoahPacing) {
2407 _heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom()));
2408 }
2409 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2410 return;
2411 }
2412 r = _regions->next();
2413 }
2414 }
2415 };
2416
2417 void ShenandoahHeap::update_heap_references(bool concurrent) {
2418 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2419 workers()->run_task(&task);
2420 }
2421
2422 void ShenandoahHeap::op_init_updaterefs() {
2423 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2424
2425 set_evacuation_in_progress(false);
2426
2427 {
2428 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs);
2429 retire_and_reset_gclabs();
2430 }
2431
2432 if (ShenandoahVerify) {
2433 if (!is_degenerated_gc_in_progress()) {
2434 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2435 }
2436 verifier()->verify_before_updaterefs();
2437 }
2438
2439 set_update_refs_in_progress(true);
2440
2441 {
2442 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare);
2443
2444 make_parsable(true);
2445
2446 // Reset iterator.
2447 _update_refs_iterator.reset();
2448 }
2449
2450 if (ShenandoahPacing) {
2451 pacer()->setup_for_updaterefs();
2452 }
2453 }
2454
2455 void ShenandoahHeap::op_final_updaterefs() {
2456 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2457
2458 finish_concurrent_unloading();
2459
2460 // Check if there is left-over work, and finish it
2461 if (_update_refs_iterator.has_next()) {
2462 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work);
2463
2464 // Finish updating references where we left off.
2465 clear_cancelled_gc();
2466 update_heap_references(false);
2467 }
2468
2469 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2470 // everything. On degenerated paths, cancelled gc would not be set anyway.
2471 if (cancelled_gc()) {
2472 clear_cancelled_gc();
2473 }
2474 assert(!cancelled_gc(), "Should have been done right before");
2475
2476 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) {
2477 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2478 }
2479
2480 if (is_degenerated_gc_in_progress()) {
2481 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
2482 } else {
2483 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2484 }
2485
2486 // Has to be done before cset is clear
2487 if (ShenandoahVerify) {
2488 verifier()->verify_roots_in_to_space();
2489 }
2490
2491 // Drop unnecessary "pinned" state from regions that does not have CP marks
2492 // anymore, as this would allow trashing them below.
2493 {
2494 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned);
2495 sync_pinned_region_status();
2496 }
2497
2498 {
2499 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset);
2500 trash_cset_regions();
2501 }
2502
2503 set_has_forwarded_objects(false);
2504 set_update_refs_in_progress(false);
2505
2506 if (ShenandoahVerify) {
2507 verifier()->verify_after_updaterefs();
2508 }
2509
2510 if (VerifyAfterGC) {
2511 Universe::verify();
2512 }
2513
2514 {
2515 ShenandoahHeapLocker locker(lock());
2516 _free_set->rebuild();
2517 }
2518 }
2519
2520 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2521 print_on(st);
2522 print_heap_regions_on(st);
2523 }
2524
2525 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2526 size_t slice = r->index() / _bitmap_regions_per_slice;
2527
2528 size_t regions_from = _bitmap_regions_per_slice * slice;
2529 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2530 for (size_t g = regions_from; g < regions_to; g++) {
2531 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2532 if (skip_self && g == r->index()) continue;
2533 if (get_region(g)->is_committed()) {
2534 return true;
2535 }
2536 }
2537 return false;
2538 }
2539
2540 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2541 shenandoah_assert_heaplocked();
2542
2543 // Bitmaps in special regions do not need commits
2544 if (_bitmap_region_special) {
2545 return true;
2546 }
2547
2548 if (is_bitmap_slice_committed(r, true)) {
2549 // Some other region from the group is already committed, meaning the bitmap
2550 // slice is already committed, we exit right away.
2551 return true;
2552 }
2553
2554 // Commit the bitmap slice:
2555 size_t slice = r->index() / _bitmap_regions_per_slice;
2556 size_t off = _bitmap_bytes_per_slice * slice;
2557 size_t len = _bitmap_bytes_per_slice;
2558 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2559 return false;
2560 }
2561 return true;
2562 }
2563
2564 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2565 shenandoah_assert_heaplocked();
2566
2567 // Bitmaps in special regions do not need uncommits
2568 if (_bitmap_region_special) {
2569 return true;
2570 }
2571
2572 if (is_bitmap_slice_committed(r, true)) {
2573 // Some other region from the group is still committed, meaning the bitmap
2574 // slice is should stay committed, exit right away.
2575 return true;
2576 }
2577
2578 // Uncommit the bitmap slice:
2579 size_t slice = r->index() / _bitmap_regions_per_slice;
2580 size_t off = _bitmap_bytes_per_slice * slice;
2581 size_t len = _bitmap_bytes_per_slice;
2582 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2583 return false;
2584 }
2585 return true;
2586 }
2587
2588 void ShenandoahHeap::safepoint_synchronize_begin() {
2589 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2590 SuspendibleThreadSet::synchronize();
2591 }
2592 }
2593
2594 void ShenandoahHeap::safepoint_synchronize_end() {
2595 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2596 SuspendibleThreadSet::desynchronize();
2597 }
2598 }
2599
2600 void ShenandoahHeap::vmop_entry_init_mark() {
2601 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2602 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2603 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2604
2605 try_inject_alloc_failure();
2606 VM_ShenandoahInitMark op;
2607 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2608 }
2609
2610 void ShenandoahHeap::vmop_entry_final_mark() {
2611 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2612 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2613 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2614
2615 try_inject_alloc_failure();
2616 VM_ShenandoahFinalMarkStartEvac op;
2617 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2618 }
2619
2620 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2621 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2622 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2623 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2624
2625 try_inject_alloc_failure();
2626 VM_ShenandoahInitUpdateRefs op;
2627 VMThread::execute(&op);
2628 }
2629
2630 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2631 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2632 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2633 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2634
2635 try_inject_alloc_failure();
2636 VM_ShenandoahFinalUpdateRefs op;
2637 VMThread::execute(&op);
2638 }
2639
2640 void ShenandoahHeap::vmop_entry_init_traversal() {
2641 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2642 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2643 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2644
2645 try_inject_alloc_failure();
2646 VM_ShenandoahInitTraversalGC op;
2647 VMThread::execute(&op);
2648 }
2649
2650 void ShenandoahHeap::vmop_entry_final_traversal() {
2651 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2652 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2653 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2654
2655 try_inject_alloc_failure();
2656 VM_ShenandoahFinalTraversalGC op;
2657 VMThread::execute(&op);
2658 }
2659
2660 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2661 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2662 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2663 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2664
2665 try_inject_alloc_failure();
2666 VM_ShenandoahFullGC op(cause);
2667 VMThread::execute(&op);
2668 }
2669
2670 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2671 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2672 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2673 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2674
2675 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2676 VMThread::execute(°enerated_gc);
2677 }
2678
2679 void ShenandoahHeap::entry_init_mark() {
2680 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2681 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2682 const char* msg = init_mark_event_message();
2683 GCTraceTime(Info, gc) time(msg, gc_timer());
2684 EventMark em("%s", msg);
2685
2686 ShenandoahWorkerScope scope(workers(),
2687 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2688 "init marking");
2689
2690 op_init_mark();
2691 }
2692
2693 void ShenandoahHeap::entry_final_mark() {
2694 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2695 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2696 const char* msg = final_mark_event_message();
2697 GCTraceTime(Info, gc) time(msg, gc_timer());
2698 EventMark em("%s", msg);
2699
2700 ShenandoahWorkerScope scope(workers(),
2701 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2702 "final marking");
2703
2704 op_final_mark();
2705 }
2706
2707 void ShenandoahHeap::entry_init_updaterefs() {
2708 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2709 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2710
2711 static const char* msg = "Pause Init Update Refs";
2712 GCTraceTime(Info, gc) time(msg, gc_timer());
2713 EventMark em("%s", msg);
2714
2715 // No workers used in this phase, no setup required
2716
2717 op_init_updaterefs();
2718 }
2719
2720 void ShenandoahHeap::entry_final_updaterefs() {
2721 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2722 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2723
2724 static const char* msg = "Pause Final Update Refs";
2725 GCTraceTime(Info, gc) time(msg, gc_timer());
2726 EventMark em("%s", msg);
2727
2728 ShenandoahWorkerScope scope(workers(),
2729 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2730 "final reference update");
2731
2732 op_final_updaterefs();
2733 }
2734
2735 void ShenandoahHeap::entry_init_traversal() {
2736 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2737 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2738
2739 static const char* msg = init_traversal_event_message();
2740 GCTraceTime(Info, gc) time(msg, gc_timer());
2741 EventMark em("%s", msg);
2742
2743 ShenandoahWorkerScope scope(workers(),
2744 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2745 "init traversal");
2746
2747 op_init_traversal();
2748 }
2749
2750 void ShenandoahHeap::entry_final_traversal() {
2751 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2752 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2753
2754 static const char* msg = final_traversal_event_message();
2755 GCTraceTime(Info, gc) time(msg, gc_timer());
2756 EventMark em("%s", msg);
2757
2758 ShenandoahWorkerScope scope(workers(),
2759 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2760 "final traversal");
2761
2762 op_final_traversal();
2763 }
2764
2765 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2766 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2767 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2768
2769 static const char* msg = "Pause Full";
2770 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2771 EventMark em("%s", msg);
2772
2773 ShenandoahWorkerScope scope(workers(),
2774 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2775 "full gc");
2776
2777 op_full(cause);
2778 }
2779
2780 void ShenandoahHeap::entry_degenerated(int point) {
2781 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2782 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2783
2784 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2785 const char* msg = degen_event_message(dpoint);
2786 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2787 EventMark em("%s", msg);
2788
2789 ShenandoahWorkerScope scope(workers(),
2790 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2791 "stw degenerated gc");
2792
2793 set_degenerated_gc_in_progress(true);
2794 op_degenerated(dpoint);
2795 set_degenerated_gc_in_progress(false);
2796 }
2797
2798 void ShenandoahHeap::entry_mark() {
2799 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2800
2801 const char* msg = conc_mark_event_message();
2802 GCTraceTime(Info, gc) time(msg);
2803 EventMark em("%s", msg);
2804
2805 ShenandoahWorkerScope scope(workers(),
2806 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2807 "concurrent marking");
2808
2809 try_inject_alloc_failure();
2810 op_mark();
2811 }
2812
2813 void ShenandoahHeap::entry_evac() {
2814 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2815 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2816
2817 static const char* msg = "Concurrent evacuation";
2818 GCTraceTime(Info, gc) time(msg);
2819 EventMark em("%s", msg);
2820
2821 ShenandoahWorkerScope scope(workers(),
2822 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2823 "concurrent evacuation");
2824
2825 try_inject_alloc_failure();
2826 op_conc_evac();
2827 }
2828
2829 void ShenandoahHeap::entry_updaterefs() {
2830 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2831
2832 static const char* msg = "Concurrent update references";
2833 GCTraceTime(Info, gc) time(msg);
2834 EventMark em("%s", msg);
2835
2836 ShenandoahWorkerScope scope(workers(),
2837 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2838 "concurrent reference update");
2839
2840 try_inject_alloc_failure();
2841 op_updaterefs();
2842 }
2843
2844 void ShenandoahHeap::entry_roots() {
2845 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots);
2846
2847 static const char* msg = "Concurrent roots processing";
2848 GCTraceTime(Info, gc) time(msg);
2849 EventMark em("%s", msg);
2850
2851 ShenandoahWorkerScope scope(workers(),
2852 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(),
2853 "concurrent root processing");
2854
2855 try_inject_alloc_failure();
2856 op_roots();
2857 }
2858
2859 void ShenandoahHeap::entry_cleanup() {
2860 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2861
2862 static const char* msg = "Concurrent cleanup";
2863 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2864 EventMark em("%s", msg);
2865
2866 // This phase does not use workers, no need for setup
2867
2868 try_inject_alloc_failure();
2869 op_cleanup();
2870 }
2871
2872 void ShenandoahHeap::entry_reset() {
2873 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2874
2875 static const char* msg = "Concurrent reset";
2876 GCTraceTime(Info, gc) time(msg);
2877 EventMark em("%s", msg);
2878
2879 ShenandoahWorkerScope scope(workers(),
2880 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2881 "concurrent reset");
2882
2883 try_inject_alloc_failure();
2884 op_reset();
2885 }
2886
2887 void ShenandoahHeap::entry_preclean() {
2888 if (ShenandoahPreclean && process_references()) {
2889 static const char* msg = "Concurrent precleaning";
2890 GCTraceTime(Info, gc) time(msg);
2891 EventMark em("%s", msg);
2892
2893 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2894
2895 ShenandoahWorkerScope scope(workers(),
2896 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2897 "concurrent preclean",
2898 /* check_workers = */ false);
2899
2900 try_inject_alloc_failure();
2901 op_preclean();
2902 }
2903 }
2904
2905 void ShenandoahHeap::entry_traversal() {
2906 static const char* msg = conc_traversal_event_message();
2907 GCTraceTime(Info, gc) time(msg);
2908 EventMark em("%s", msg);
2909
2910 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2911
2912 ShenandoahWorkerScope scope(workers(),
2913 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2914 "concurrent traversal");
2915
2916 try_inject_alloc_failure();
2917 op_traversal();
2918 }
2919
2920 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2921 static const char *msg = "Concurrent uncommit";
2922 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2923 EventMark em("%s", msg);
2924
2925 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2926
2927 op_uncommit(shrink_before);
2928 }
2929
2930 void ShenandoahHeap::try_inject_alloc_failure() {
2931 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2932 _inject_alloc_failure.set();
2933 os::naked_short_sleep(1);
2934 if (cancelled_gc()) {
2935 log_info(gc)("Allocation failure was successfully injected");
2936 }
2937 }
2938 }
2939
2940 bool ShenandoahHeap::should_inject_alloc_failure() {
2941 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2942 }
2943
2944 void ShenandoahHeap::initialize_serviceability() {
2945 _memory_pool = new ShenandoahMemoryPool(this);
2946 _cycle_memory_manager.add_pool(_memory_pool);
2947 _stw_memory_manager.add_pool(_memory_pool);
2948 }
2949
2950 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2951 GrowableArray<GCMemoryManager*> memory_managers(2);
2952 memory_managers.append(&_cycle_memory_manager);
2953 memory_managers.append(&_stw_memory_manager);
2954 return memory_managers;
2955 }
2956
2957 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2958 GrowableArray<MemoryPool*> memory_pools(1);
2959 memory_pools.append(_memory_pool);
2960 return memory_pools;
2961 }
2962
2963 MemoryUsage ShenandoahHeap::memory_usage() {
2964 return _memory_pool->get_memory_usage();
2965 }
2966
2967 void ShenandoahHeap::enter_evacuation() {
2968 _oom_evac_handler.enter_evacuation();
2969 }
2970
2971 void ShenandoahHeap::leave_evacuation() {
2972 _oom_evac_handler.leave_evacuation();
2973 }
2974
2975 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2976 _heap(ShenandoahHeap::heap()),
2977 _index(0) {}
2978
2979 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2980 _heap(heap),
2981 _index(0) {}
2982
2983 void ShenandoahRegionIterator::reset() {
2984 _index = 0;
2985 }
2986
2987 bool ShenandoahRegionIterator::has_next() const {
2988 return _index < _heap->num_regions();
2989 }
2990
2991 char ShenandoahHeap::gc_state() const {
2992 return _gc_state.raw_value();
2993 }
2994
2995 void ShenandoahHeap::deduplicate_string(oop str) {
2996 assert(java_lang_String::is_instance(str), "invariant");
2997
2998 if (ShenandoahStringDedup::is_enabled()) {
2999 ShenandoahStringDedup::deduplicate(str);
3000 }
3001 }
3002
3003 const char* ShenandoahHeap::init_mark_event_message() const {
3004 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3005
3006 bool proc_refs = process_references();
3007 bool unload_cls = unload_classes();
3008
3009 if (proc_refs && unload_cls) {
3010 return "Pause Init Mark (process weakrefs) (unload classes)";
3011 } else if (proc_refs) {
3012 return "Pause Init Mark (process weakrefs)";
3013 } else if (unload_cls) {
3014 return "Pause Init Mark (unload classes)";
3015 } else {
3016 return "Pause Init Mark";
3017 }
3018 }
3019
3020 const char* ShenandoahHeap::final_mark_event_message() const {
3021 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3022
3023 bool proc_refs = process_references();
3024 bool unload_cls = unload_classes();
3025
3026 if (proc_refs && unload_cls) {
3027 return "Pause Final Mark (process weakrefs) (unload classes)";
3028 } else if (proc_refs) {
3029 return "Pause Final Mark (process weakrefs)";
3030 } else if (unload_cls) {
3031 return "Pause Final Mark (unload classes)";
3032 } else {
3033 return "Pause Final Mark";
3034 }
3035 }
3036
3037 const char* ShenandoahHeap::conc_mark_event_message() const {
3038 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3039
3040 bool proc_refs = process_references();
3041 bool unload_cls = unload_classes();
3042
3043 if (proc_refs && unload_cls) {
3044 return "Concurrent marking (process weakrefs) (unload classes)";
3045 } else if (proc_refs) {
3046 return "Concurrent marking (process weakrefs)";
3047 } else if (unload_cls) {
3048 return "Concurrent marking (unload classes)";
3049 } else {
3050 return "Concurrent marking";
3051 }
3052 }
3053
3054 const char* ShenandoahHeap::init_traversal_event_message() const {
3055 bool proc_refs = process_references();
3056 bool unload_cls = unload_classes();
3057
3058 if (proc_refs && unload_cls) {
3059 return "Pause Init Traversal (process weakrefs) (unload classes)";
3060 } else if (proc_refs) {
3061 return "Pause Init Traversal (process weakrefs)";
3062 } else if (unload_cls) {
3063 return "Pause Init Traversal (unload classes)";
3064 } else {
3065 return "Pause Init Traversal";
3066 }
3067 }
3068
3069 const char* ShenandoahHeap::final_traversal_event_message() const {
3070 bool proc_refs = process_references();
3071 bool unload_cls = unload_classes();
3072
3073 if (proc_refs && unload_cls) {
3074 return "Pause Final Traversal (process weakrefs) (unload classes)";
3075 } else if (proc_refs) {
3076 return "Pause Final Traversal (process weakrefs)";
3077 } else if (unload_cls) {
3078 return "Pause Final Traversal (unload classes)";
3079 } else {
3080 return "Pause Final Traversal";
3081 }
3082 }
3083
3084 const char* ShenandoahHeap::conc_traversal_event_message() const {
3085 bool proc_refs = process_references();
3086 bool unload_cls = unload_classes();
3087
3088 if (proc_refs && unload_cls) {
3089 return "Concurrent Traversal (process weakrefs) (unload classes)";
3090 } else if (proc_refs) {
3091 return "Concurrent Traversal (process weakrefs)";
3092 } else if (unload_cls) {
3093 return "Concurrent Traversal (unload classes)";
3094 } else {
3095 return "Concurrent Traversal";
3096 }
3097 }
3098
3099 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
3100 switch (point) {
3101 case _degenerated_unset:
3102 return "Pause Degenerated GC (<UNSET>)";
3103 case _degenerated_traversal:
3104 return "Pause Degenerated GC (Traversal)";
3105 case _degenerated_outside_cycle:
3106 return "Pause Degenerated GC (Outside of Cycle)";
3107 case _degenerated_mark:
3108 return "Pause Degenerated GC (Mark)";
3109 case _degenerated_evac:
3110 return "Pause Degenerated GC (Evacuation)";
3111 case _degenerated_updaterefs:
3112 return "Pause Degenerated GC (Update Refs)";
3113 default:
3114 ShouldNotReachHere();
3115 return "ERROR";
3116 }
3117 }
3118
3119 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
3120 #ifdef ASSERT
3121 assert(_liveness_cache != NULL, "sanity");
3122 assert(worker_id < _max_workers, "sanity");
3123 for (uint i = 0; i < num_regions(); i++) {
3124 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
3125 }
3126 #endif
3127 return _liveness_cache[worker_id];
3128 }
3129
3130 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
3131 assert(worker_id < _max_workers, "sanity");
3132 assert(_liveness_cache != NULL, "sanity");
3133 jushort* ld = _liveness_cache[worker_id];
3134 for (uint i = 0; i < num_regions(); i++) {
3135 ShenandoahHeapRegion* r = get_region(i);
3136 jushort live = ld[i];
3137 if (live > 0) {
3138 r->increase_live_data_gc_words(live);
3139 ld[i] = 0;
3140 }
3141 }
3142 }