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