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