1 /* 2 * Copyright (c) 2013, 2021, Red Hat, Inc. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.hpp" 27 #include "memory/universe.hpp" 28 29 #include "gc/shared/gcArguments.hpp" 30 #include "gc/shared/gcTimer.hpp" 31 #include "gc/shared/gcTraceTime.inline.hpp" 32 #include "gc/shared/locationPrinter.inline.hpp" 33 #include "gc/shared/memAllocator.hpp" 34 #include "gc/shared/plab.hpp" 35 #include "gc/shared/slidingForwarding.hpp" 36 #include "gc/shared/tlab_globals.hpp" 37 38 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 39 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 40 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 41 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 42 #include "gc/shenandoah/shenandoahConcurrentMark.hpp" 43 #include "gc/shenandoah/shenandoahControlThread.hpp" 44 #include "gc/shenandoah/shenandoahFreeSet.hpp" 45 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 46 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 47 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp" 48 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 49 #include "gc/shenandoah/shenandoahInitLogger.hpp" 50 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 51 #include "gc/shenandoah/shenandoahMemoryPool.hpp" 52 #include "gc/shenandoah/shenandoahMetrics.hpp" 53 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp" 54 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 55 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 56 #include "gc/shenandoah/shenandoahPadding.hpp" 57 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp" 58 #include "gc/shenandoah/shenandoahReferenceProcessor.hpp" 59 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 60 #include "gc/shenandoah/shenandoahStringDedup.hpp" 61 #include "gc/shenandoah/shenandoahSTWMark.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 #include "gc/shenandoah/mode/shenandoahIUMode.hpp" 69 #include "gc/shenandoah/mode/shenandoahPassiveMode.hpp" 70 #include "gc/shenandoah/mode/shenandoahSATBMode.hpp" 71 #if INCLUDE_JFR 72 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 73 #endif 74 75 #include "classfile/systemDictionary.hpp" 76 #include "memory/classLoaderMetaspace.hpp" 77 #include "memory/metaspaceUtils.hpp" 78 #include "oops/compressedOops.inline.hpp" 79 #include "prims/jvmtiTagMap.hpp" 80 #include "runtime/atomic.hpp" 81 #include "runtime/globals.hpp" 82 #include "runtime/interfaceSupport.inline.hpp" 83 #include "runtime/java.hpp" 84 #include "runtime/orderAccess.hpp" 85 #include "runtime/safepointMechanism.hpp" 86 #include "runtime/vmThread.hpp" 87 #include "services/mallocTracker.hpp" 88 #include "services/memTracker.hpp" 89 #include "utilities/events.hpp" 90 #include "utilities/powerOfTwo.hpp" 91 92 class ShenandoahPretouchHeapTask : public WorkerTask { 93 private: 94 ShenandoahRegionIterator _regions; 95 const size_t _page_size; 96 public: 97 ShenandoahPretouchHeapTask(size_t page_size) : 98 WorkerTask("Shenandoah Pretouch Heap"), 99 _page_size(page_size) {} 100 101 virtual void work(uint worker_id) { 102 ShenandoahHeapRegion* r = _regions.next(); 103 while (r != NULL) { 104 if (r->is_committed()) { 105 os::pretouch_memory(r->bottom(), r->end(), _page_size); 106 } 107 r = _regions.next(); 108 } 109 } 110 }; 111 112 class ShenandoahPretouchBitmapTask : public WorkerTask { 113 private: 114 ShenandoahRegionIterator _regions; 115 char* _bitmap_base; 116 const size_t _bitmap_size; 117 const size_t _page_size; 118 public: 119 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 120 WorkerTask("Shenandoah Pretouch Bitmap"), 121 _bitmap_base(bitmap_base), 122 _bitmap_size(bitmap_size), 123 _page_size(page_size) {} 124 125 virtual void work(uint worker_id) { 126 ShenandoahHeapRegion* r = _regions.next(); 127 while (r != NULL) { 128 size_t start = r->index() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 129 size_t end = (r->index() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 130 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 131 132 if (r->is_committed()) { 133 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 134 } 135 136 r = _regions.next(); 137 } 138 } 139 }; 140 141 jint ShenandoahHeap::initialize() { 142 // 143 // Figure out heap sizing 144 // 145 146 size_t init_byte_size = InitialHeapSize; 147 size_t min_byte_size = MinHeapSize; 148 size_t max_byte_size = MaxHeapSize; 149 size_t heap_alignment = HeapAlignment; 150 151 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 152 153 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 154 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 155 156 _num_regions = ShenandoahHeapRegion::region_count(); 157 assert(_num_regions == (max_byte_size / reg_size_bytes), 158 "Regions should cover entire heap exactly: " SIZE_FORMAT " != " SIZE_FORMAT "/" SIZE_FORMAT, 159 _num_regions, max_byte_size, reg_size_bytes); 160 161 // Now we know the number of regions, initialize the heuristics. 162 initialize_heuristics(); 163 164 size_t num_committed_regions = init_byte_size / reg_size_bytes; 165 num_committed_regions = MIN2(num_committed_regions, _num_regions); 166 assert(num_committed_regions <= _num_regions, "sanity"); 167 _initial_size = num_committed_regions * reg_size_bytes; 168 169 size_t num_min_regions = min_byte_size / reg_size_bytes; 170 num_min_regions = MIN2(num_min_regions, _num_regions); 171 assert(num_min_regions <= _num_regions, "sanity"); 172 _minimum_size = num_min_regions * reg_size_bytes; 173 174 // Default to max heap size. 175 _soft_max_size = _num_regions * reg_size_bytes; 176 177 _committed = _initial_size; 178 179 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 180 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 181 size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 182 183 // 184 // Reserve and commit memory for heap 185 // 186 187 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 188 initialize_reserved_region(heap_rs); 189 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 190 _heap_region_special = heap_rs.special(); 191 192 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 193 "Misaligned heap: " PTR_FORMAT, p2i(base())); 194 195 _forwarding = new SlidingForwarding(_heap_region, ShenandoahHeapRegion::region_size_words_shift()); 196 197 #if SHENANDOAH_OPTIMIZED_MARKTASK 198 // The optimized ShenandoahMarkTask takes some bits away from the full object bits. 199 // Fail if we ever attempt to address more than we can. 200 if ((uintptr_t)heap_rs.end() >= ShenandoahMarkTask::max_addressable()) { 201 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 202 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 203 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 204 p2i(heap_rs.base()), p2i(heap_rs.end()), ShenandoahMarkTask::max_addressable()); 205 vm_exit_during_initialization("Fatal Error", buf); 206 } 207 #endif 208 209 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 210 if (!_heap_region_special) { 211 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 212 "Cannot commit heap memory"); 213 } 214 215 // 216 // Reserve and commit memory for bitmap(s) 217 // 218 219 _bitmap_size = ShenandoahMarkBitMap::compute_size(heap_rs.size()); 220 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 221 222 size_t bitmap_bytes_per_region = reg_size_bytes / ShenandoahMarkBitMap::heap_map_factor(); 223 224 guarantee(bitmap_bytes_per_region != 0, 225 "Bitmap bytes per region should not be zero"); 226 guarantee(is_power_of_2(bitmap_bytes_per_region), 227 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 228 229 if (bitmap_page_size > bitmap_bytes_per_region) { 230 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 231 _bitmap_bytes_per_slice = bitmap_page_size; 232 } else { 233 _bitmap_regions_per_slice = 1; 234 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 235 } 236 237 guarantee(_bitmap_regions_per_slice >= 1, 238 "Should have at least one region per slice: " SIZE_FORMAT, 239 _bitmap_regions_per_slice); 240 241 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 242 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 243 _bitmap_bytes_per_slice, bitmap_page_size); 244 245 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 246 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 247 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 248 _bitmap_region_special = bitmap.special(); 249 250 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 251 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 252 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 253 if (!_bitmap_region_special) { 254 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 255 "Cannot commit bitmap memory"); 256 } 257 258 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions, _max_workers); 259 260 if (ShenandoahVerify) { 261 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 262 if (!verify_bitmap.special()) { 263 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 264 "Cannot commit verification bitmap memory"); 265 } 266 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 267 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 268 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 269 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 270 } 271 272 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 273 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 274 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 275 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 276 _aux_bitmap_region_special = aux_bitmap.special(); 277 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 278 279 // 280 // Create regions and region sets 281 // 282 size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE); 283 size_t region_storage_size = align_up(region_align * _num_regions, region_page_size); 284 region_storage_size = align_up(region_storage_size, os::vm_allocation_granularity()); 285 286 ReservedSpace region_storage(region_storage_size, region_page_size); 287 MemTracker::record_virtual_memory_type(region_storage.base(), mtGC); 288 if (!region_storage.special()) { 289 os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false, 290 "Cannot commit region memory"); 291 } 292 293 // Try to fit the collection set bitmap at lower addresses. This optimizes code generation for cset checks. 294 // Go up until a sensible limit (subject to encoding constraints) and try to reserve the space there. 295 // If not successful, bite a bullet and allocate at whatever address. 296 { 297 size_t cset_align = MAX2<size_t>(os::vm_page_size(), os::vm_allocation_granularity()); 298 size_t cset_size = align_up(((size_t) sh_rs.base() + sh_rs.size()) >> ShenandoahHeapRegion::region_size_bytes_shift(), cset_align); 299 300 uintptr_t min = round_up_power_of_2(cset_align); 301 uintptr_t max = (1u << 30u); 302 303 for (uintptr_t addr = min; addr <= max; addr <<= 1u) { 304 char* req_addr = (char*)addr; 305 assert(is_aligned(req_addr, cset_align), "Should be aligned"); 306 ReservedSpace cset_rs(cset_size, cset_align, os::vm_page_size(), req_addr); 307 if (cset_rs.is_reserved()) { 308 assert(cset_rs.base() == req_addr, "Allocated where requested: " PTR_FORMAT ", " PTR_FORMAT, p2i(cset_rs.base()), addr); 309 _collection_set = new ShenandoahCollectionSet(this, cset_rs, sh_rs.base()); 310 break; 311 } 312 } 313 314 if (_collection_set == NULL) { 315 ReservedSpace cset_rs(cset_size, cset_align, os::vm_page_size()); 316 _collection_set = new ShenandoahCollectionSet(this, cset_rs, sh_rs.base()); 317 } 318 } 319 320 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 321 _free_set = new ShenandoahFreeSet(this, _num_regions); 322 323 { 324 ShenandoahHeapLocker locker(lock()); 325 326 for (size_t i = 0; i < _num_regions; i++) { 327 HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i; 328 bool is_committed = i < num_committed_regions; 329 void* loc = region_storage.base() + i * region_align; 330 331 ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed); 332 assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity"); 333 334 _marking_context->initialize_top_at_mark_start(r); 335 _regions[i] = r; 336 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 337 } 338 339 // Initialize to complete 340 _marking_context->mark_complete(); 341 342 _free_set->rebuild(); 343 } 344 345 if (AlwaysPreTouch) { 346 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 347 // before initialize() below zeroes it with initializing thread. For any given region, 348 // we touch the region and the corresponding bitmaps from the same thread. 349 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 350 351 _pretouch_heap_page_size = heap_page_size; 352 _pretouch_bitmap_page_size = bitmap_page_size; 353 354 #ifdef LINUX 355 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 356 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 357 // them into huge one. Therefore, we need to pretouch with smaller pages. 358 if (UseTransparentHugePages) { 359 _pretouch_heap_page_size = (size_t)os::vm_page_size(); 360 _pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 361 } 362 #endif 363 364 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 365 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 366 367 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, _pretouch_bitmap_page_size); 368 _workers->run_task(&bcl); 369 370 ShenandoahPretouchHeapTask hcl(_pretouch_heap_page_size); 371 _workers->run_task(&hcl); 372 } 373 374 // 375 // Initialize the rest of GC subsystems 376 // 377 378 _liveness_cache = NEW_C_HEAP_ARRAY(ShenandoahLiveData*, _max_workers, mtGC); 379 for (uint worker = 0; worker < _max_workers; worker++) { 380 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(ShenandoahLiveData, _num_regions, mtGC); 381 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(ShenandoahLiveData)); 382 } 383 384 // There should probably be Shenandoah-specific options for these, 385 // just as there are G1-specific options. 386 { 387 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set(); 388 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold 389 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent 390 } 391 392 _monitoring_support = new ShenandoahMonitoringSupport(this); 393 _phase_timings = new ShenandoahPhaseTimings(max_workers()); 394 ShenandoahCodeRoots::initialize(); 395 396 if (ShenandoahPacing) { 397 _pacer = new ShenandoahPacer(this); 398 _pacer->setup_for_idle(); 399 } else { 400 _pacer = NULL; 401 } 402 403 _control_thread = new ShenandoahControlThread(); 404 405 ShenandoahInitLogger::print(); 406 407 return JNI_OK; 408 } 409 410 void ShenandoahHeap::initialize_mode() { 411 if (ShenandoahGCMode != NULL) { 412 if (strcmp(ShenandoahGCMode, "satb") == 0) { 413 _gc_mode = new ShenandoahSATBMode(); 414 } else if (strcmp(ShenandoahGCMode, "iu") == 0) { 415 _gc_mode = new ShenandoahIUMode(); 416 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 417 _gc_mode = new ShenandoahPassiveMode(); 418 } else { 419 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 420 } 421 } else { 422 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option (null)"); 423 } 424 _gc_mode->initialize_flags(); 425 if (_gc_mode->is_diagnostic() && !UnlockDiagnosticVMOptions) { 426 vm_exit_during_initialization( 427 err_msg("GC mode \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 428 _gc_mode->name())); 429 } 430 if (_gc_mode->is_experimental() && !UnlockExperimentalVMOptions) { 431 vm_exit_during_initialization( 432 err_msg("GC mode \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 433 _gc_mode->name())); 434 } 435 } 436 437 void ShenandoahHeap::initialize_heuristics() { 438 assert(_gc_mode != NULL, "Must be initialized"); 439 _heuristics = _gc_mode->initialize_heuristics(); 440 441 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 442 vm_exit_during_initialization( 443 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 444 _heuristics->name())); 445 } 446 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 447 vm_exit_during_initialization( 448 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 449 _heuristics->name())); 450 } 451 } 452 453 #ifdef _MSC_VER 454 #pragma warning( push ) 455 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 456 #endif 457 458 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 459 CollectedHeap(), 460 _initial_size(0), 461 _used(0), 462 _committed(0), 463 _bytes_allocated_since_gc_start(0), 464 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), 465 _workers(NULL), 466 _safepoint_workers(NULL), 467 _heap_region_special(false), 468 _num_regions(0), 469 _regions(NULL), 470 _update_refs_iterator(this), 471 _control_thread(NULL), 472 _shenandoah_policy(policy), 473 _gc_mode(NULL), 474 _heuristics(NULL), 475 _free_set(NULL), 476 _pacer(NULL), 477 _verifier(NULL), 478 _phase_timings(NULL), 479 _monitoring_support(NULL), 480 _memory_pool(NULL), 481 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), 482 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), 483 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 484 _soft_ref_policy(), 485 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes), 486 _ref_processor(new ShenandoahReferenceProcessor(MAX2(_max_workers, 1U))), 487 _marking_context(NULL), 488 _bitmap_size(0), 489 _bitmap_regions_per_slice(0), 490 _bitmap_bytes_per_slice(0), 491 _bitmap_region_special(false), 492 _aux_bitmap_region_special(false), 493 _liveness_cache(NULL), 494 _collection_set(NULL) 495 { 496 // Initialize GC mode early, so we can adjust barrier support 497 initialize_mode(); 498 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); 499 500 _max_workers = MAX2(_max_workers, 1U); 501 _workers = new ShenandoahWorkerThreads("Shenandoah GC Threads", _max_workers); 502 if (_workers == NULL) { 503 vm_exit_during_initialization("Failed necessary allocation."); 504 } else { 505 _workers->initialize_workers(); 506 } 507 508 if (ParallelGCThreads > 1) { 509 _safepoint_workers = new ShenandoahWorkerThreads("Safepoint Cleanup Thread", 510 ParallelGCThreads); 511 _safepoint_workers->initialize_workers(); 512 } 513 } 514 515 #ifdef _MSC_VER 516 #pragma warning( pop ) 517 #endif 518 519 class ShenandoahResetBitmapTask : public WorkerTask { 520 private: 521 ShenandoahRegionIterator _regions; 522 523 public: 524 ShenandoahResetBitmapTask() : 525 WorkerTask("Shenandoah Reset Bitmap") {} 526 527 void work(uint worker_id) { 528 ShenandoahHeapRegion* region = _regions.next(); 529 ShenandoahHeap* heap = ShenandoahHeap::heap(); 530 ShenandoahMarkingContext* const ctx = heap->marking_context(); 531 while (region != NULL) { 532 if (heap->is_bitmap_slice_committed(region)) { 533 ctx->clear_bitmap(region); 534 } 535 region = _regions.next(); 536 } 537 } 538 }; 539 540 void ShenandoahHeap::reset_mark_bitmap() { 541 assert_gc_workers(_workers->active_workers()); 542 mark_incomplete_marking_context(); 543 544 ShenandoahResetBitmapTask task; 545 _workers->run_task(&task); 546 } 547 548 void ShenandoahHeap::print_on(outputStream* st) const { 549 st->print_cr("Shenandoah Heap"); 550 st->print_cr(" " SIZE_FORMAT "%s max, " SIZE_FORMAT "%s soft max, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 551 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 552 byte_size_in_proper_unit(soft_max_capacity()), proper_unit_for_byte_size(soft_max_capacity()), 553 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 554 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 555 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 556 num_regions(), 557 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 558 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 559 560 st->print("Status: "); 561 if (has_forwarded_objects()) st->print("has forwarded objects, "); 562 if (is_concurrent_mark_in_progress()) st->print("marking, "); 563 if (is_evacuation_in_progress()) st->print("evacuating, "); 564 if (is_update_refs_in_progress()) st->print("updating refs, "); 565 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 566 if (is_full_gc_in_progress()) st->print("full gc, "); 567 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 568 if (is_concurrent_weak_root_in_progress()) st->print("concurrent weak roots, "); 569 if (is_concurrent_strong_root_in_progress() && 570 !is_concurrent_weak_root_in_progress()) st->print("concurrent strong roots, "); 571 572 if (cancelled_gc()) { 573 st->print("cancelled"); 574 } else { 575 st->print("not cancelled"); 576 } 577 st->cr(); 578 579 st->print_cr("Reserved region:"); 580 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 581 p2i(reserved_region().start()), 582 p2i(reserved_region().end())); 583 584 ShenandoahCollectionSet* cset = collection_set(); 585 st->print_cr("Collection set:"); 586 if (cset != NULL) { 587 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 588 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 589 } else { 590 st->print_cr(" (NULL)"); 591 } 592 593 st->cr(); 594 MetaspaceUtils::print_on(st); 595 596 if (Verbose) { 597 print_heap_regions_on(st); 598 } 599 } 600 601 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 602 public: 603 void do_thread(Thread* thread) { 604 assert(thread != NULL, "Sanity"); 605 assert(thread->is_Worker_thread(), "Only worker thread expected"); 606 ShenandoahThreadLocalData::initialize_gclab(thread); 607 } 608 }; 609 610 void ShenandoahHeap::post_initialize() { 611 CollectedHeap::post_initialize(); 612 MutexLocker ml(Threads_lock); 613 614 ShenandoahInitWorkerGCLABClosure init_gclabs; 615 _workers->threads_do(&init_gclabs); 616 617 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 618 // Now, we will let WorkerThreads to initialize gclab when new worker is created. 619 _workers->set_initialize_gclab(); 620 if (_safepoint_workers != NULL) { 621 _safepoint_workers->threads_do(&init_gclabs); 622 _safepoint_workers->set_initialize_gclab(); 623 } 624 625 _heuristics->initialize(); 626 627 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 628 } 629 630 size_t ShenandoahHeap::used() const { 631 return Atomic::load(&_used); 632 } 633 634 size_t ShenandoahHeap::committed() const { 635 return Atomic::load(&_committed); 636 } 637 638 void ShenandoahHeap::increase_committed(size_t bytes) { 639 shenandoah_assert_heaplocked_or_safepoint(); 640 _committed += bytes; 641 } 642 643 void ShenandoahHeap::decrease_committed(size_t bytes) { 644 shenandoah_assert_heaplocked_or_safepoint(); 645 _committed -= bytes; 646 } 647 648 void ShenandoahHeap::increase_used(size_t bytes) { 649 Atomic::add(&_used, bytes, memory_order_relaxed); 650 } 651 652 void ShenandoahHeap::set_used(size_t bytes) { 653 Atomic::store(&_used, bytes); 654 } 655 656 void ShenandoahHeap::decrease_used(size_t bytes) { 657 assert(used() >= bytes, "never decrease heap size by more than we've left"); 658 Atomic::sub(&_used, bytes, memory_order_relaxed); 659 } 660 661 void ShenandoahHeap::increase_allocated(size_t bytes) { 662 Atomic::add(&_bytes_allocated_since_gc_start, bytes, memory_order_relaxed); 663 } 664 665 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 666 size_t bytes = words * HeapWordSize; 667 if (!waste) { 668 increase_used(bytes); 669 } 670 increase_allocated(bytes); 671 if (ShenandoahPacing) { 672 control_thread()->pacing_notify_alloc(words); 673 if (waste) { 674 pacer()->claim_for_alloc(words, true); 675 } 676 } 677 } 678 679 size_t ShenandoahHeap::capacity() const { 680 return committed(); 681 } 682 683 size_t ShenandoahHeap::max_capacity() const { 684 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 685 } 686 687 size_t ShenandoahHeap::soft_max_capacity() const { 688 size_t v = Atomic::load(&_soft_max_size); 689 assert(min_capacity() <= v && v <= max_capacity(), 690 "Should be in bounds: " SIZE_FORMAT " <= " SIZE_FORMAT " <= " SIZE_FORMAT, 691 min_capacity(), v, max_capacity()); 692 return v; 693 } 694 695 void ShenandoahHeap::set_soft_max_capacity(size_t v) { 696 assert(min_capacity() <= v && v <= max_capacity(), 697 "Should be in bounds: " SIZE_FORMAT " <= " SIZE_FORMAT " <= " SIZE_FORMAT, 698 min_capacity(), v, max_capacity()); 699 Atomic::store(&_soft_max_size, v); 700 } 701 702 size_t ShenandoahHeap::min_capacity() const { 703 return _minimum_size; 704 } 705 706 size_t ShenandoahHeap::initial_capacity() const { 707 return _initial_size; 708 } 709 710 bool ShenandoahHeap::is_in(const void* p) const { 711 HeapWord* heap_base = (HeapWord*) base(); 712 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 713 return p >= heap_base && p < last_region_end; 714 } 715 716 void ShenandoahHeap::op_uncommit(double shrink_before, size_t shrink_until) { 717 assert (ShenandoahUncommit, "should be enabled"); 718 719 // Application allocates from the beginning of the heap, and GC allocates at 720 // the end of it. It is more efficient to uncommit from the end, so that applications 721 // could enjoy the near committed regions. GC allocations are much less frequent, 722 // and therefore can accept the committing costs. 723 724 size_t count = 0; 725 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 726 ShenandoahHeapRegion* r = get_region(i - 1); 727 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 728 ShenandoahHeapLocker locker(lock()); 729 if (r->is_empty_committed()) { 730 if (committed() < shrink_until + ShenandoahHeapRegion::region_size_bytes()) { 731 break; 732 } 733 734 r->make_uncommitted(); 735 count++; 736 } 737 } 738 SpinPause(); // allow allocators to take the lock 739 } 740 741 if (count > 0) { 742 control_thread()->notify_heap_changed(); 743 } 744 } 745 746 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 747 // New object should fit the GCLAB size 748 size_t min_size = MAX2(size, PLAB::min_size()); 749 750 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 751 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 752 new_size = MIN2(new_size, PLAB::max_size()); 753 new_size = MAX2(new_size, PLAB::min_size()); 754 755 // Record new heuristic value even if we take any shortcut. This captures 756 // the case when moderately-sized objects always take a shortcut. At some point, 757 // heuristics should catch up with them. 758 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 759 760 if (new_size < size) { 761 // New size still does not fit the object. Fall back to shared allocation. 762 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 763 return NULL; 764 } 765 766 // Retire current GCLAB, and allocate a new one. 767 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 768 gclab->retire(); 769 770 size_t actual_size = 0; 771 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 772 if (gclab_buf == NULL) { 773 return NULL; 774 } 775 776 assert (size <= actual_size, "allocation should fit"); 777 778 if (ZeroTLAB) { 779 // ..and clear it. 780 Copy::zero_to_words(gclab_buf, actual_size); 781 } else { 782 // ...and zap just allocated object. 783 #ifdef ASSERT 784 // Skip mangling the space corresponding to the object header to 785 // ensure that the returned space is not considered parsable by 786 // any concurrent GC thread. 787 size_t hdr_size = oopDesc::header_size(); 788 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 789 #endif // ASSERT 790 } 791 gclab->set_buf(gclab_buf, actual_size); 792 return gclab->allocate(size); 793 } 794 795 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 796 size_t requested_size, 797 size_t* actual_size) { 798 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 799 HeapWord* res = allocate_memory(req); 800 if (res != NULL) { 801 *actual_size = req.actual_size(); 802 } else { 803 *actual_size = 0; 804 } 805 return res; 806 } 807 808 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 809 size_t word_size, 810 size_t* actual_size) { 811 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 812 HeapWord* res = allocate_memory(req); 813 if (res != NULL) { 814 *actual_size = req.actual_size(); 815 } else { 816 *actual_size = 0; 817 } 818 return res; 819 } 820 821 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 822 intptr_t pacer_epoch = 0; 823 bool in_new_region = false; 824 HeapWord* result = NULL; 825 826 if (req.is_mutator_alloc()) { 827 if (ShenandoahPacing) { 828 pacer()->pace_for_alloc(req.size()); 829 pacer_epoch = pacer()->epoch(); 830 } 831 832 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 833 result = allocate_memory_under_lock(req, in_new_region); 834 } 835 836 // Allocation failed, block until control thread reacted, then retry allocation. 837 // 838 // It might happen that one of the threads requesting allocation would unblock 839 // way later after GC happened, only to fail the second allocation, because 840 // other threads have already depleted the free storage. In this case, a better 841 // strategy is to try again, as long as GC makes progress. 842 // 843 // Then, we need to make sure the allocation was retried after at least one 844 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 845 846 size_t tries = 0; 847 848 while (result == NULL && _progress_last_gc.is_set()) { 849 tries++; 850 control_thread()->handle_alloc_failure(req); 851 result = allocate_memory_under_lock(req, in_new_region); 852 } 853 854 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 855 tries++; 856 control_thread()->handle_alloc_failure(req); 857 result = allocate_memory_under_lock(req, in_new_region); 858 } 859 860 } else { 861 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 862 result = allocate_memory_under_lock(req, in_new_region); 863 // Do not call handle_alloc_failure() here, because we cannot block. 864 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 865 } 866 867 if (in_new_region) { 868 control_thread()->notify_heap_changed(); 869 } 870 871 if (result != NULL) { 872 size_t requested = req.size(); 873 size_t actual = req.actual_size(); 874 875 assert (req.is_lab_alloc() || (requested == actual), 876 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 877 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 878 879 if (req.is_mutator_alloc()) { 880 notify_mutator_alloc_words(actual, false); 881 882 // If we requested more than we were granted, give the rest back to pacer. 883 // This only matters if we are in the same pacing epoch: do not try to unpace 884 // over the budget for the other phase. 885 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 886 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 887 } 888 } else { 889 increase_used(actual*HeapWordSize); 890 } 891 } 892 893 return result; 894 } 895 896 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 897 ShenandoahHeapLocker locker(lock()); 898 return _free_set->allocate(req, in_new_region); 899 } 900 901 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 902 bool* gc_overhead_limit_was_exceeded) { 903 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 904 return allocate_memory(req); 905 } 906 907 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 908 size_t size, 909 Metaspace::MetadataType mdtype) { 910 MetaWord* result; 911 912 // Inform metaspace OOM to GC heuristics if class unloading is possible. 913 if (heuristics()->can_unload_classes()) { 914 ShenandoahHeuristics* h = heuristics(); 915 h->record_metaspace_oom(); 916 } 917 918 // Expand and retry allocation 919 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 920 if (result != NULL) { 921 return result; 922 } 923 924 // Start full GC 925 collect(GCCause::_metadata_GC_clear_soft_refs); 926 927 // Retry allocation 928 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 929 if (result != NULL) { 930 return result; 931 } 932 933 // Expand and retry allocation 934 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 935 if (result != NULL) { 936 return result; 937 } 938 939 // Out of memory 940 return NULL; 941 } 942 943 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 944 private: 945 ShenandoahHeap* const _heap; 946 Thread* const _thread; 947 public: 948 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 949 _heap(heap), _thread(Thread::current()) {} 950 951 void do_object(oop p) { 952 shenandoah_assert_marked(NULL, p); 953 if (!ShenandoahForwarding::is_forwarded(p)) { 954 _heap->evacuate_object(p, _thread); 955 } 956 } 957 }; 958 959 class ShenandoahEvacuationTask : public WorkerTask { 960 private: 961 ShenandoahHeap* const _sh; 962 ShenandoahCollectionSet* const _cs; 963 bool _concurrent; 964 public: 965 ShenandoahEvacuationTask(ShenandoahHeap* sh, 966 ShenandoahCollectionSet* cs, 967 bool concurrent) : 968 WorkerTask("Shenandoah Evacuation"), 969 _sh(sh), 970 _cs(cs), 971 _concurrent(concurrent) 972 {} 973 974 void work(uint worker_id) { 975 if (_concurrent) { 976 ShenandoahConcurrentWorkerSession worker_session(worker_id); 977 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 978 ShenandoahEvacOOMScope oom_evac_scope; 979 do_work(); 980 } else { 981 ShenandoahParallelWorkerSession worker_session(worker_id); 982 ShenandoahEvacOOMScope oom_evac_scope; 983 do_work(); 984 } 985 } 986 987 private: 988 void do_work() { 989 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 990 ShenandoahHeapRegion* r; 991 while ((r =_cs->claim_next()) != NULL) { 992 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->index()); 993 _sh->marked_object_iterate(r, &cl); 994 995 if (ShenandoahPacing) { 996 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 997 } 998 999 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 1000 break; 1001 } 1002 } 1003 } 1004 }; 1005 1006 void ShenandoahHeap::evacuate_collection_set(bool concurrent) { 1007 ShenandoahEvacuationTask task(this, _collection_set, concurrent); 1008 workers()->run_task(&task); 1009 } 1010 1011 void ShenandoahHeap::trash_cset_regions() { 1012 ShenandoahHeapLocker locker(lock()); 1013 1014 ShenandoahCollectionSet* set = collection_set(); 1015 ShenandoahHeapRegion* r; 1016 set->clear_current_index(); 1017 while ((r = set->next()) != NULL) { 1018 r->make_trash(); 1019 } 1020 collection_set()->clear(); 1021 } 1022 1023 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 1024 st->print_cr("Heap Regions:"); 1025 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 1026 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 1027 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark"); 1028 st->print_cr("SN=alloc sequence number"); 1029 1030 for (size_t i = 0; i < num_regions(); i++) { 1031 get_region(i)->print_on(st); 1032 } 1033 } 1034 1035 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 1036 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1037 1038 oop humongous_obj = cast_to_oop(start->bottom()); 1039 size_t size = humongous_obj->size(); 1040 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1041 size_t index = start->index() + required_regions - 1; 1042 1043 assert(!start->has_live(), "liveness must be zero"); 1044 1045 for(size_t i = 0; i < required_regions; i++) { 1046 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1047 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1048 ShenandoahHeapRegion* region = get_region(index --); 1049 1050 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1051 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1052 1053 region->make_trash_immediate(); 1054 } 1055 } 1056 1057 class ShenandoahCheckCleanGCLABClosure : public ThreadClosure { 1058 public: 1059 ShenandoahCheckCleanGCLABClosure() {} 1060 void do_thread(Thread* thread) { 1061 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1062 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1063 assert(gclab->words_remaining() == 0, "GCLAB should not need retirement"); 1064 } 1065 }; 1066 1067 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1068 private: 1069 bool const _resize; 1070 public: 1071 ShenandoahRetireGCLABClosure(bool resize) : _resize(resize) {} 1072 void do_thread(Thread* thread) { 1073 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1074 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1075 gclab->retire(); 1076 if (_resize && ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1077 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1078 } 1079 } 1080 }; 1081 1082 void ShenandoahHeap::labs_make_parsable() { 1083 assert(UseTLAB, "Only call with UseTLAB"); 1084 1085 ShenandoahRetireGCLABClosure cl(false); 1086 1087 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1088 ThreadLocalAllocBuffer& tlab = t->tlab(); 1089 tlab.make_parsable(); 1090 cl.do_thread(t); 1091 } 1092 1093 workers()->threads_do(&cl); 1094 } 1095 1096 void ShenandoahHeap::tlabs_retire(bool resize) { 1097 assert(UseTLAB, "Only call with UseTLAB"); 1098 assert(!resize || ResizeTLAB, "Only call for resize when ResizeTLAB is enabled"); 1099 1100 ThreadLocalAllocStats stats; 1101 1102 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1103 ThreadLocalAllocBuffer& tlab = t->tlab(); 1104 tlab.retire(&stats); 1105 if (resize) { 1106 tlab.resize(); 1107 } 1108 } 1109 1110 stats.publish(); 1111 1112 #ifdef ASSERT 1113 ShenandoahCheckCleanGCLABClosure cl; 1114 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1115 cl.do_thread(t); 1116 } 1117 workers()->threads_do(&cl); 1118 #endif 1119 } 1120 1121 void ShenandoahHeap::gclabs_retire(bool resize) { 1122 assert(UseTLAB, "Only call with UseTLAB"); 1123 assert(!resize || ResizeTLAB, "Only call for resize when ResizeTLAB is enabled"); 1124 1125 ShenandoahRetireGCLABClosure cl(resize); 1126 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1127 cl.do_thread(t); 1128 } 1129 workers()->threads_do(&cl); 1130 1131 if (safepoint_workers() != NULL) { 1132 safepoint_workers()->threads_do(&cl); 1133 } 1134 } 1135 1136 // Returns size in bytes 1137 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1138 if (ShenandoahElasticTLAB) { 1139 // With Elastic TLABs, return the max allowed size, and let the allocation path 1140 // figure out the safe size for current allocation. 1141 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1142 } else { 1143 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1144 } 1145 } 1146 1147 size_t ShenandoahHeap::max_tlab_size() const { 1148 // Returns size in words 1149 return ShenandoahHeapRegion::max_tlab_size_words(); 1150 } 1151 1152 void ShenandoahHeap::collect(GCCause::Cause cause) { 1153 control_thread()->request_gc(cause); 1154 } 1155 1156 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1157 //assert(false, "Shouldn't need to do full collections"); 1158 } 1159 1160 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1161 ShenandoahHeapRegion* r = heap_region_containing(addr); 1162 if (r != NULL) { 1163 return r->block_start(addr); 1164 } 1165 return NULL; 1166 } 1167 1168 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1169 ShenandoahHeapRegion* r = heap_region_containing(addr); 1170 return r->block_is_obj(addr); 1171 } 1172 1173 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const { 1174 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr); 1175 } 1176 1177 void ShenandoahHeap::prepare_for_verify() { 1178 if (SafepointSynchronize::is_at_safepoint() && UseTLAB) { 1179 labs_make_parsable(); 1180 } 1181 } 1182 1183 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1184 workers()->threads_do(tcl); 1185 if (_safepoint_workers != NULL) { 1186 _safepoint_workers->threads_do(tcl); 1187 } 1188 if (ShenandoahStringDedup::is_enabled()) { 1189 ShenandoahStringDedup::threads_do(tcl); 1190 } 1191 } 1192 1193 void ShenandoahHeap::print_tracing_info() const { 1194 LogTarget(Info, gc, stats) lt; 1195 if (lt.is_enabled()) { 1196 ResourceMark rm; 1197 LogStream ls(lt); 1198 1199 phase_timings()->print_global_on(&ls); 1200 1201 ls.cr(); 1202 ls.cr(); 1203 1204 shenandoah_policy()->print_gc_stats(&ls); 1205 1206 ls.cr(); 1207 ls.cr(); 1208 } 1209 } 1210 1211 void ShenandoahHeap::verify(VerifyOption vo) { 1212 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1213 if (ShenandoahVerify) { 1214 verifier()->verify_generic(vo); 1215 } else { 1216 // TODO: Consider allocating verification bitmaps on demand, 1217 // and turn this on unconditionally. 1218 } 1219 } 1220 } 1221 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1222 return _free_set->capacity(); 1223 } 1224 1225 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1226 private: 1227 MarkBitMap* _bitmap; 1228 ShenandoahScanObjectStack* _oop_stack; 1229 ShenandoahHeap* const _heap; 1230 ShenandoahMarkingContext* const _marking_context; 1231 1232 template <class T> 1233 void do_oop_work(T* p) { 1234 T o = RawAccess<>::oop_load(p); 1235 if (!CompressedOops::is_null(o)) { 1236 oop obj = CompressedOops::decode_not_null(o); 1237 if (_heap->is_concurrent_weak_root_in_progress() && !_marking_context->is_marked(obj)) { 1238 // There may be dead oops in weak roots in concurrent root phase, do not touch them. 1239 return; 1240 } 1241 1242 // We must not expose from-space oops to the rest of runtime, or else it 1243 // will call klass() on it, which might fail because of unexpected header. 1244 obj = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(obj); 1245 1246 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1247 if (!_bitmap->is_marked(obj)) { 1248 _bitmap->mark(obj); 1249 _oop_stack->push(obj); 1250 } 1251 } 1252 } 1253 public: 1254 ObjectIterateScanRootClosure(MarkBitMap* bitmap, ShenandoahScanObjectStack* oop_stack) : 1255 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()), 1256 _marking_context(_heap->marking_context()) {} 1257 void do_oop(oop* p) { do_oop_work(p); } 1258 void do_oop(narrowOop* p) { do_oop_work(p); } 1259 }; 1260 1261 /* 1262 * This is public API, used in preparation of object_iterate(). 1263 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1264 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1265 * control, we call SH::tlabs_retire, SH::gclabs_retire. 1266 */ 1267 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1268 // No-op. 1269 } 1270 1271 /* 1272 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1273 * 1274 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1275 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1276 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1277 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1278 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1279 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1280 * wiped the bitmap in preparation for next marking). 1281 * 1282 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1283 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1284 * is allowed to report dead objects, but is not required to do so. 1285 */ 1286 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1287 // Reset bitmap 1288 if (!prepare_aux_bitmap_for_iteration()) 1289 return; 1290 1291 ShenandoahScanObjectStack oop_stack; 1292 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1293 // Seed the stack with root scan 1294 scan_roots_for_iteration(&oop_stack, &oops); 1295 1296 // Work through the oop stack to traverse heap 1297 while (! oop_stack.is_empty()) { 1298 oop obj = oop_stack.pop(); 1299 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1300 shenandoah_assert_not_in_cset_except(NULL, obj, cancelled_gc()); 1301 cl->do_object(obj); 1302 obj->oop_iterate(&oops); 1303 } 1304 1305 assert(oop_stack.is_empty(), "should be empty"); 1306 // Reclaim bitmap 1307 reclaim_aux_bitmap_for_iteration(); 1308 } 1309 1310 bool ShenandoahHeap::prepare_aux_bitmap_for_iteration() { 1311 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1312 1313 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1314 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1315 return false; 1316 } 1317 // Reset bitmap 1318 _aux_bit_map.clear(); 1319 return true; 1320 } 1321 1322 void ShenandoahHeap::scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops) { 1323 // Process GC roots according to current GC cycle 1324 // This populates the work stack with initial objects 1325 // It is important to relinquish the associated locks before diving 1326 // into heap dumper 1327 uint n_workers = safepoint_workers() != NULL ? safepoint_workers()->active_workers() : 1; 1328 ShenandoahHeapIterationRootScanner rp(n_workers); 1329 rp.roots_do(oops); 1330 } 1331 1332 void ShenandoahHeap::reclaim_aux_bitmap_for_iteration() { 1333 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1334 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1335 } 1336 } 1337 1338 // Closure for parallelly iterate objects 1339 class ShenandoahObjectIterateParScanClosure : public BasicOopIterateClosure { 1340 private: 1341 MarkBitMap* _bitmap; 1342 ShenandoahObjToScanQueue* _queue; 1343 ShenandoahHeap* const _heap; 1344 ShenandoahMarkingContext* const _marking_context; 1345 1346 template <class T> 1347 void do_oop_work(T* p) { 1348 T o = RawAccess<>::oop_load(p); 1349 if (!CompressedOops::is_null(o)) { 1350 oop obj = CompressedOops::decode_not_null(o); 1351 if (_heap->is_concurrent_weak_root_in_progress() && !_marking_context->is_marked(obj)) { 1352 // There may be dead oops in weak roots in concurrent root phase, do not touch them. 1353 return; 1354 } 1355 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1356 1357 assert(oopDesc::is_oop(obj), "Must be a valid oop"); 1358 if (_bitmap->par_mark(obj)) { 1359 _queue->push(ShenandoahMarkTask(obj)); 1360 } 1361 } 1362 } 1363 public: 1364 ShenandoahObjectIterateParScanClosure(MarkBitMap* bitmap, ShenandoahObjToScanQueue* q) : 1365 _bitmap(bitmap), _queue(q), _heap(ShenandoahHeap::heap()), 1366 _marking_context(_heap->marking_context()) {} 1367 void do_oop(oop* p) { do_oop_work(p); } 1368 void do_oop(narrowOop* p) { do_oop_work(p); } 1369 }; 1370 1371 // Object iterator for parallel heap iteraion. 1372 // The root scanning phase happenes in construction as a preparation of 1373 // parallel marking queues. 1374 // Every worker processes it's own marking queue. work-stealing is used 1375 // to balance workload. 1376 class ShenandoahParallelObjectIterator : public ParallelObjectIteratorImpl { 1377 private: 1378 uint _num_workers; 1379 bool _init_ready; 1380 MarkBitMap* _aux_bit_map; 1381 ShenandoahHeap* _heap; 1382 ShenandoahScanObjectStack _roots_stack; // global roots stack 1383 ShenandoahObjToScanQueueSet* _task_queues; 1384 public: 1385 ShenandoahParallelObjectIterator(uint num_workers, MarkBitMap* bitmap) : 1386 _num_workers(num_workers), 1387 _init_ready(false), 1388 _aux_bit_map(bitmap), 1389 _heap(ShenandoahHeap::heap()) { 1390 // Initialize bitmap 1391 _init_ready = _heap->prepare_aux_bitmap_for_iteration(); 1392 if (!_init_ready) { 1393 return; 1394 } 1395 1396 ObjectIterateScanRootClosure oops(_aux_bit_map, &_roots_stack); 1397 _heap->scan_roots_for_iteration(&_roots_stack, &oops); 1398 1399 _init_ready = prepare_worker_queues(); 1400 } 1401 1402 ~ShenandoahParallelObjectIterator() { 1403 // Reclaim bitmap 1404 _heap->reclaim_aux_bitmap_for_iteration(); 1405 // Reclaim queue for workers 1406 if (_task_queues!= NULL) { 1407 for (uint i = 0; i < _num_workers; ++i) { 1408 ShenandoahObjToScanQueue* q = _task_queues->queue(i); 1409 if (q != NULL) { 1410 delete q; 1411 _task_queues->register_queue(i, NULL); 1412 } 1413 } 1414 delete _task_queues; 1415 _task_queues = NULL; 1416 } 1417 } 1418 1419 virtual void object_iterate(ObjectClosure* cl, uint worker_id) { 1420 if (_init_ready) { 1421 object_iterate_parallel(cl, worker_id, _task_queues); 1422 } 1423 } 1424 1425 private: 1426 // Divide global root_stack into worker queues 1427 bool prepare_worker_queues() { 1428 _task_queues = new ShenandoahObjToScanQueueSet((int) _num_workers); 1429 // Initialize queues for every workers 1430 for (uint i = 0; i < _num_workers; ++i) { 1431 ShenandoahObjToScanQueue* task_queue = new ShenandoahObjToScanQueue(); 1432 _task_queues->register_queue(i, task_queue); 1433 } 1434 // Divide roots among the workers. Assume that object referencing distribution 1435 // is related with root kind, use round-robin to make every worker have same chance 1436 // to process every kind of roots 1437 size_t roots_num = _roots_stack.size(); 1438 if (roots_num == 0) { 1439 // No work to do 1440 return false; 1441 } 1442 1443 for (uint j = 0; j < roots_num; j++) { 1444 uint stack_id = j % _num_workers; 1445 oop obj = _roots_stack.pop(); 1446 _task_queues->queue(stack_id)->push(ShenandoahMarkTask(obj)); 1447 } 1448 return true; 1449 } 1450 1451 void object_iterate_parallel(ObjectClosure* cl, 1452 uint worker_id, 1453 ShenandoahObjToScanQueueSet* queue_set) { 1454 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1455 assert(queue_set != NULL, "task queue must not be NULL"); 1456 1457 ShenandoahObjToScanQueue* q = queue_set->queue(worker_id); 1458 assert(q != NULL, "object iterate queue must not be NULL"); 1459 1460 ShenandoahMarkTask t; 1461 ShenandoahObjectIterateParScanClosure oops(_aux_bit_map, q); 1462 1463 // Work through the queue to traverse heap. 1464 // Steal when there is no task in queue. 1465 while (q->pop(t) || queue_set->steal(worker_id, t)) { 1466 oop obj = t.obj(); 1467 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1468 cl->do_object(obj); 1469 obj->oop_iterate(&oops); 1470 } 1471 assert(q->is_empty(), "should be empty"); 1472 } 1473 }; 1474 1475 ParallelObjectIteratorImpl* ShenandoahHeap::parallel_object_iterator(uint workers) { 1476 return new ShenandoahParallelObjectIterator(workers, &_aux_bit_map); 1477 } 1478 1479 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 1480 void ShenandoahHeap::keep_alive(oop obj) { 1481 if (is_concurrent_mark_in_progress() && (obj != NULL)) { 1482 ShenandoahBarrierSet::barrier_set()->enqueue(obj); 1483 } 1484 } 1485 1486 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1487 for (size_t i = 0; i < num_regions(); i++) { 1488 ShenandoahHeapRegion* current = get_region(i); 1489 blk->heap_region_do(current); 1490 } 1491 } 1492 1493 class ShenandoahParallelHeapRegionTask : public WorkerTask { 1494 private: 1495 ShenandoahHeap* const _heap; 1496 ShenandoahHeapRegionClosure* const _blk; 1497 1498 shenandoah_padding(0); 1499 volatile size_t _index; 1500 shenandoah_padding(1); 1501 1502 public: 1503 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1504 WorkerTask("Shenandoah Parallel Region Operation"), 1505 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1506 1507 void work(uint worker_id) { 1508 ShenandoahParallelWorkerSession worker_session(worker_id); 1509 size_t stride = ShenandoahParallelRegionStride; 1510 1511 size_t max = _heap->num_regions(); 1512 while (Atomic::load(&_index) < max) { 1513 size_t cur = Atomic::fetch_and_add(&_index, stride, memory_order_relaxed); 1514 size_t start = cur; 1515 size_t end = MIN2(cur + stride, max); 1516 if (start >= max) break; 1517 1518 for (size_t i = cur; i < end; i++) { 1519 ShenandoahHeapRegion* current = _heap->get_region(i); 1520 _blk->heap_region_do(current); 1521 } 1522 } 1523 } 1524 }; 1525 1526 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1527 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1528 if (num_regions() > ShenandoahParallelRegionStride) { 1529 ShenandoahParallelHeapRegionTask task(blk); 1530 workers()->run_task(&task); 1531 } else { 1532 heap_region_iterate(blk); 1533 } 1534 } 1535 1536 class ShenandoahInitMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1537 private: 1538 ShenandoahMarkingContext* const _ctx; 1539 public: 1540 ShenandoahInitMarkUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1541 1542 void heap_region_do(ShenandoahHeapRegion* r) { 1543 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1544 if (r->is_active()) { 1545 // Check if region needs updating its TAMS. We have updated it already during concurrent 1546 // reset, so it is very likely we don't need to do another write here. 1547 if (_ctx->top_at_mark_start(r) != r->top()) { 1548 _ctx->capture_top_at_mark_start(r); 1549 } 1550 } else { 1551 assert(_ctx->top_at_mark_start(r) == r->top(), 1552 "Region " SIZE_FORMAT " should already have correct TAMS", r->index()); 1553 } 1554 } 1555 1556 bool is_thread_safe() { return true; } 1557 }; 1558 1559 class ShenandoahRendezvousClosure : public HandshakeClosure { 1560 public: 1561 inline ShenandoahRendezvousClosure() : HandshakeClosure("ShenandoahRendezvous") {} 1562 inline void do_thread(Thread* thread) {} 1563 }; 1564 1565 void ShenandoahHeap::rendezvous_threads() { 1566 ShenandoahRendezvousClosure cl; 1567 Handshake::execute(&cl); 1568 } 1569 1570 void ShenandoahHeap::recycle_trash() { 1571 free_set()->recycle_trash(); 1572 } 1573 1574 class ShenandoahResetUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1575 private: 1576 ShenandoahMarkingContext* const _ctx; 1577 public: 1578 ShenandoahResetUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1579 1580 void heap_region_do(ShenandoahHeapRegion* r) { 1581 if (r->is_active()) { 1582 // Reset live data and set TAMS optimistically. We would recheck these under the pause 1583 // anyway to capture any updates that happened since now. 1584 r->clear_live_data(); 1585 _ctx->capture_top_at_mark_start(r); 1586 } 1587 } 1588 1589 bool is_thread_safe() { return true; } 1590 }; 1591 1592 void ShenandoahHeap::prepare_gc() { 1593 reset_mark_bitmap(); 1594 1595 ShenandoahResetUpdateRegionStateClosure cl; 1596 parallel_heap_region_iterate(&cl); 1597 } 1598 1599 class ShenandoahFinalMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1600 private: 1601 ShenandoahMarkingContext* const _ctx; 1602 ShenandoahHeapLock* const _lock; 1603 1604 public: 1605 ShenandoahFinalMarkUpdateRegionStateClosure() : 1606 _ctx(ShenandoahHeap::heap()->complete_marking_context()), _lock(ShenandoahHeap::heap()->lock()) {} 1607 1608 void heap_region_do(ShenandoahHeapRegion* r) { 1609 if (r->is_active()) { 1610 // All allocations past TAMS are implicitly live, adjust the region data. 1611 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1612 HeapWord *tams = _ctx->top_at_mark_start(r); 1613 HeapWord *top = r->top(); 1614 if (top > tams) { 1615 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1616 } 1617 1618 // We are about to select the collection set, make sure it knows about 1619 // current pinning status. Also, this allows trashing more regions that 1620 // now have their pinning status dropped. 1621 if (r->is_pinned()) { 1622 if (r->pin_count() == 0) { 1623 ShenandoahHeapLocker locker(_lock); 1624 r->make_unpinned(); 1625 } 1626 } else { 1627 if (r->pin_count() > 0) { 1628 ShenandoahHeapLocker locker(_lock); 1629 r->make_pinned(); 1630 } 1631 } 1632 1633 // Remember limit for updating refs. It's guaranteed that we get no 1634 // from-space-refs written from here on. 1635 r->set_update_watermark_at_safepoint(r->top()); 1636 } else { 1637 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1638 assert(_ctx->top_at_mark_start(r) == r->top(), 1639 "Region " SIZE_FORMAT " should have correct TAMS", r->index()); 1640 } 1641 } 1642 1643 bool is_thread_safe() { return true; } 1644 }; 1645 1646 void ShenandoahHeap::prepare_regions_and_collection_set(bool concurrent) { 1647 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 1648 { 1649 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_update_region_states : 1650 ShenandoahPhaseTimings::degen_gc_final_update_region_states); 1651 ShenandoahFinalMarkUpdateRegionStateClosure cl; 1652 parallel_heap_region_iterate(&cl); 1653 1654 assert_pinned_region_status(); 1655 } 1656 1657 { 1658 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::choose_cset : 1659 ShenandoahPhaseTimings::degen_gc_choose_cset); 1660 ShenandoahHeapLocker locker(lock()); 1661 _collection_set->clear(); 1662 heuristics()->choose_collection_set(_collection_set); 1663 } 1664 1665 { 1666 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_rebuild_freeset : 1667 ShenandoahPhaseTimings::degen_gc_final_rebuild_freeset); 1668 ShenandoahHeapLocker locker(lock()); 1669 _free_set->rebuild(); 1670 } 1671 } 1672 1673 void ShenandoahHeap::do_class_unloading() { 1674 _unloader.unload(); 1675 } 1676 1677 void ShenandoahHeap::stw_weak_refs(bool full_gc) { 1678 // Weak refs processing 1679 ShenandoahPhaseTimings::Phase phase = full_gc ? ShenandoahPhaseTimings::full_gc_weakrefs 1680 : ShenandoahPhaseTimings::degen_gc_weakrefs; 1681 ShenandoahTimingsTracker t(phase); 1682 ShenandoahGCWorkerPhase worker_phase(phase); 1683 ref_processor()->process_references(phase, workers(), false /* concurrent */); 1684 } 1685 1686 void ShenandoahHeap::prepare_update_heap_references(bool concurrent) { 1687 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 1688 1689 // Evacuation is over, no GCLABs are needed anymore. GCLABs are under URWM, so we need to 1690 // make them parsable for update code to work correctly. Plus, we can compute new sizes 1691 // for future GCLABs here. 1692 if (UseTLAB) { 1693 ShenandoahGCPhase phase(concurrent ? 1694 ShenandoahPhaseTimings::init_update_refs_manage_gclabs : 1695 ShenandoahPhaseTimings::degen_gc_init_update_refs_manage_gclabs); 1696 gclabs_retire(ResizeTLAB); 1697 } 1698 1699 _update_refs_iterator.reset(); 1700 } 1701 1702 void ShenandoahHeap::set_gc_state_all_threads(char state) { 1703 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1704 ShenandoahThreadLocalData::set_gc_state(t, state); 1705 } 1706 } 1707 1708 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1709 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1710 _gc_state.set_cond(mask, value); 1711 set_gc_state_all_threads(_gc_state.raw_value()); 1712 } 1713 1714 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1715 assert(!has_forwarded_objects(), "Not expected before/after mark phase"); 1716 set_gc_state_mask(MARKING, in_progress); 1717 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1718 } 1719 1720 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1721 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1722 set_gc_state_mask(EVACUATION, in_progress); 1723 } 1724 1725 void ShenandoahHeap::set_concurrent_strong_root_in_progress(bool in_progress) { 1726 if (in_progress) { 1727 _concurrent_strong_root_in_progress.set(); 1728 } else { 1729 _concurrent_strong_root_in_progress.unset(); 1730 } 1731 } 1732 1733 void ShenandoahHeap::set_concurrent_weak_root_in_progress(bool cond) { 1734 set_gc_state_mask(WEAK_ROOTS, cond); 1735 } 1736 1737 GCTracer* ShenandoahHeap::tracer() { 1738 return shenandoah_policy()->tracer(); 1739 } 1740 1741 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1742 return _free_set->used(); 1743 } 1744 1745 bool ShenandoahHeap::try_cancel_gc() { 1746 while (true) { 1747 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 1748 if (prev == CANCELLABLE) return true; 1749 else if (prev == CANCELLED) return false; 1750 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 1751 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 1752 Thread* thread = Thread::current(); 1753 if (thread->is_Java_thread()) { 1754 // We need to provide a safepoint here, otherwise we might 1755 // spin forever if a SP is pending. 1756 ThreadBlockInVM sp(JavaThread::cast(thread)); 1757 SpinPause(); 1758 } 1759 } 1760 } 1761 1762 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 1763 if (try_cancel_gc()) { 1764 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 1765 log_info(gc)("%s", msg.buffer()); 1766 Events::log(Thread::current(), "%s", msg.buffer()); 1767 } 1768 } 1769 1770 uint ShenandoahHeap::max_workers() { 1771 return _max_workers; 1772 } 1773 1774 void ShenandoahHeap::stop() { 1775 // The shutdown sequence should be able to terminate when GC is running. 1776 1777 // Step 0. Notify policy to disable event recording. 1778 _shenandoah_policy->record_shutdown(); 1779 1780 // Step 1. Notify control thread that we are in shutdown. 1781 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 1782 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 1783 control_thread()->prepare_for_graceful_shutdown(); 1784 1785 // Step 2. Notify GC workers that we are cancelling GC. 1786 cancel_gc(GCCause::_shenandoah_stop_vm); 1787 1788 // Step 3. Wait until GC worker exits normally. 1789 control_thread()->stop(); 1790 } 1791 1792 void ShenandoahHeap::stw_unload_classes(bool full_gc) { 1793 if (!unload_classes()) return; 1794 // Unload classes and purge SystemDictionary. 1795 { 1796 ShenandoahPhaseTimings::Phase phase = full_gc ? 1797 ShenandoahPhaseTimings::full_gc_purge_class_unload : 1798 ShenandoahPhaseTimings::degen_gc_purge_class_unload; 1799 ShenandoahGCPhase gc_phase(phase); 1800 ShenandoahGCWorkerPhase worker_phase(phase); 1801 bool purged_class = SystemDictionary::do_unloading(gc_timer()); 1802 1803 ShenandoahIsAliveSelector is_alive; 1804 uint num_workers = _workers->active_workers(); 1805 ShenandoahClassUnloadingTask unlink_task(phase, is_alive.is_alive_closure(), num_workers, purged_class); 1806 _workers->run_task(&unlink_task); 1807 } 1808 1809 { 1810 ShenandoahGCPhase phase(full_gc ? 1811 ShenandoahPhaseTimings::full_gc_purge_cldg : 1812 ShenandoahPhaseTimings::degen_gc_purge_cldg); 1813 ClassLoaderDataGraph::purge(/*at_safepoint*/true); 1814 } 1815 // Resize and verify metaspace 1816 MetaspaceGC::compute_new_size(); 1817 DEBUG_ONLY(MetaspaceUtils::verify();) 1818 } 1819 1820 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs), 1821 // so they should not have forwarded oops. 1822 // However, we do need to "null" dead oops in the roots, if can not be done 1823 // in concurrent cycles. 1824 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) { 1825 uint num_workers = _workers->active_workers(); 1826 ShenandoahPhaseTimings::Phase timing_phase = full_gc ? 1827 ShenandoahPhaseTimings::full_gc_purge_weak_par : 1828 ShenandoahPhaseTimings::degen_gc_purge_weak_par; 1829 ShenandoahGCPhase phase(timing_phase); 1830 ShenandoahGCWorkerPhase worker_phase(timing_phase); 1831 // Cleanup weak roots 1832 if (has_forwarded_objects()) { 1833 ShenandoahForwardedIsAliveClosure is_alive; 1834 ShenandoahUpdateRefsClosure keep_alive; 1835 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure> 1836 cleaning_task(timing_phase, &is_alive, &keep_alive, num_workers); 1837 _workers->run_task(&cleaning_task); 1838 } else { 1839 ShenandoahIsAliveClosure is_alive; 1840 #ifdef ASSERT 1841 ShenandoahAssertNotForwardedClosure verify_cl; 1842 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure> 1843 cleaning_task(timing_phase, &is_alive, &verify_cl, num_workers); 1844 #else 1845 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure> 1846 cleaning_task(timing_phase, &is_alive, &do_nothing_cl, num_workers); 1847 #endif 1848 _workers->run_task(&cleaning_task); 1849 } 1850 } 1851 1852 void ShenandoahHeap::parallel_cleaning(bool full_gc) { 1853 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1854 assert(is_stw_gc_in_progress(), "Only for Degenerated and Full GC"); 1855 ShenandoahGCPhase phase(full_gc ? 1856 ShenandoahPhaseTimings::full_gc_purge : 1857 ShenandoahPhaseTimings::degen_gc_purge); 1858 stw_weak_refs(full_gc); 1859 stw_process_weak_roots(full_gc); 1860 stw_unload_classes(full_gc); 1861 } 1862 1863 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 1864 set_gc_state_mask(HAS_FORWARDED, cond); 1865 } 1866 1867 void ShenandoahHeap::set_unload_classes(bool uc) { 1868 _unload_classes.set_cond(uc); 1869 } 1870 1871 bool ShenandoahHeap::unload_classes() const { 1872 return _unload_classes.is_set(); 1873 } 1874 1875 address ShenandoahHeap::in_cset_fast_test_addr() { 1876 ShenandoahHeap* heap = ShenandoahHeap::heap(); 1877 assert(heap->collection_set() != NULL, "Sanity"); 1878 return (address) heap->collection_set()->biased_map_address(); 1879 } 1880 1881 address ShenandoahHeap::cancelled_gc_addr() { 1882 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 1883 } 1884 1885 address ShenandoahHeap::gc_state_addr() { 1886 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 1887 } 1888 1889 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 1890 return Atomic::load(&_bytes_allocated_since_gc_start); 1891 } 1892 1893 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 1894 Atomic::store(&_bytes_allocated_since_gc_start, (size_t)0); 1895 } 1896 1897 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 1898 _degenerated_gc_in_progress.set_cond(in_progress); 1899 } 1900 1901 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 1902 _full_gc_in_progress.set_cond(in_progress); 1903 } 1904 1905 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 1906 assert (is_full_gc_in_progress(), "should be"); 1907 _full_gc_move_in_progress.set_cond(in_progress); 1908 } 1909 1910 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 1911 set_gc_state_mask(UPDATEREFS, in_progress); 1912 } 1913 1914 void ShenandoahHeap::register_nmethod(nmethod* nm) { 1915 ShenandoahCodeRoots::register_nmethod(nm); 1916 } 1917 1918 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 1919 ShenandoahCodeRoots::unregister_nmethod(nm); 1920 } 1921 1922 void ShenandoahHeap::flush_nmethod(nmethod* nm) { 1923 ShenandoahCodeRoots::flush_nmethod(nm); 1924 } 1925 1926 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 1927 heap_region_containing(o)->record_pin(); 1928 return o; 1929 } 1930 1931 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 1932 ShenandoahHeapRegion* r = heap_region_containing(o); 1933 assert(r != NULL, "Sanity"); 1934 assert(r->pin_count() > 0, "Region " SIZE_FORMAT " should have non-zero pins", r->index()); 1935 r->record_unpin(); 1936 } 1937 1938 void ShenandoahHeap::sync_pinned_region_status() { 1939 ShenandoahHeapLocker locker(lock()); 1940 1941 for (size_t i = 0; i < num_regions(); i++) { 1942 ShenandoahHeapRegion *r = get_region(i); 1943 if (r->is_active()) { 1944 if (r->is_pinned()) { 1945 if (r->pin_count() == 0) { 1946 r->make_unpinned(); 1947 } 1948 } else { 1949 if (r->pin_count() > 0) { 1950 r->make_pinned(); 1951 } 1952 } 1953 } 1954 } 1955 1956 assert_pinned_region_status(); 1957 } 1958 1959 #ifdef ASSERT 1960 void ShenandoahHeap::assert_pinned_region_status() { 1961 for (size_t i = 0; i < num_regions(); i++) { 1962 ShenandoahHeapRegion* r = get_region(i); 1963 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 1964 "Region " SIZE_FORMAT " pinning status is inconsistent", i); 1965 } 1966 } 1967 #endif 1968 1969 ConcurrentGCTimer* ShenandoahHeap::gc_timer() const { 1970 return _gc_timer; 1971 } 1972 1973 void ShenandoahHeap::prepare_concurrent_roots() { 1974 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1975 assert(!is_stw_gc_in_progress(), "Only concurrent GC"); 1976 set_concurrent_strong_root_in_progress(!collection_set()->is_empty()); 1977 set_concurrent_weak_root_in_progress(true); 1978 if (unload_classes()) { 1979 _unloader.prepare(); 1980 } 1981 } 1982 1983 void ShenandoahHeap::finish_concurrent_roots() { 1984 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1985 assert(!is_stw_gc_in_progress(), "Only concurrent GC"); 1986 if (unload_classes()) { 1987 _unloader.finish(); 1988 } 1989 } 1990 1991 #ifdef ASSERT 1992 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 1993 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 1994 1995 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1996 if (UseDynamicNumberOfGCThreads) { 1997 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 1998 } else { 1999 // Use ParallelGCThreads inside safepoints 2000 assert(nworkers == ParallelGCThreads, "Use ParallelGCThreads within safepoints"); 2001 } 2002 } else { 2003 if (UseDynamicNumberOfGCThreads) { 2004 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2005 } else { 2006 // Use ConcGCThreads outside safepoints 2007 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2008 } 2009 } 2010 } 2011 #endif 2012 2013 ShenandoahVerifier* ShenandoahHeap::verifier() { 2014 guarantee(ShenandoahVerify, "Should be enabled"); 2015 assert (_verifier != NULL, "sanity"); 2016 return _verifier; 2017 } 2018 2019 template<bool CONCURRENT> 2020 class ShenandoahUpdateHeapRefsTask : public WorkerTask { 2021 private: 2022 ShenandoahHeap* _heap; 2023 ShenandoahRegionIterator* _regions; 2024 public: 2025 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions) : 2026 WorkerTask("Shenandoah Update References"), 2027 _heap(ShenandoahHeap::heap()), 2028 _regions(regions) { 2029 } 2030 2031 void work(uint worker_id) { 2032 if (CONCURRENT) { 2033 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2034 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2035 do_work<ShenandoahConcUpdateRefsClosure>(); 2036 } else { 2037 ShenandoahParallelWorkerSession worker_session(worker_id); 2038 do_work<ShenandoahSTWUpdateRefsClosure>(); 2039 } 2040 } 2041 2042 private: 2043 template<class T> 2044 void do_work() { 2045 T cl; 2046 ShenandoahHeapRegion* r = _regions->next(); 2047 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2048 while (r != NULL) { 2049 HeapWord* update_watermark = r->get_update_watermark(); 2050 assert (update_watermark >= r->bottom(), "sanity"); 2051 if (r->is_active() && !r->is_cset()) { 2052 _heap->marked_object_oop_iterate(r, &cl, update_watermark); 2053 } 2054 if (ShenandoahPacing) { 2055 _heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom())); 2056 } 2057 if (_heap->check_cancelled_gc_and_yield(CONCURRENT)) { 2058 return; 2059 } 2060 r = _regions->next(); 2061 } 2062 } 2063 }; 2064 2065 void ShenandoahHeap::update_heap_references(bool concurrent) { 2066 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 2067 2068 if (concurrent) { 2069 ShenandoahUpdateHeapRefsTask<true> task(&_update_refs_iterator); 2070 workers()->run_task(&task); 2071 } else { 2072 ShenandoahUpdateHeapRefsTask<false> task(&_update_refs_iterator); 2073 workers()->run_task(&task); 2074 } 2075 } 2076 2077 2078 class ShenandoahFinalUpdateRefsUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 2079 private: 2080 ShenandoahHeapLock* const _lock; 2081 2082 public: 2083 ShenandoahFinalUpdateRefsUpdateRegionStateClosure() : _lock(ShenandoahHeap::heap()->lock()) {} 2084 2085 void heap_region_do(ShenandoahHeapRegion* r) { 2086 // Drop unnecessary "pinned" state from regions that does not have CP marks 2087 // anymore, as this would allow trashing them. 2088 2089 if (r->is_active()) { 2090 if (r->is_pinned()) { 2091 if (r->pin_count() == 0) { 2092 ShenandoahHeapLocker locker(_lock); 2093 r->make_unpinned(); 2094 } 2095 } else { 2096 if (r->pin_count() > 0) { 2097 ShenandoahHeapLocker locker(_lock); 2098 r->make_pinned(); 2099 } 2100 } 2101 } 2102 } 2103 2104 bool is_thread_safe() { return true; } 2105 }; 2106 2107 void ShenandoahHeap::update_heap_region_states(bool concurrent) { 2108 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2109 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 2110 2111 { 2112 ShenandoahGCPhase phase(concurrent ? 2113 ShenandoahPhaseTimings::final_update_refs_update_region_states : 2114 ShenandoahPhaseTimings::degen_gc_final_update_refs_update_region_states); 2115 ShenandoahFinalUpdateRefsUpdateRegionStateClosure cl; 2116 parallel_heap_region_iterate(&cl); 2117 2118 assert_pinned_region_status(); 2119 } 2120 2121 { 2122 ShenandoahGCPhase phase(concurrent ? 2123 ShenandoahPhaseTimings::final_update_refs_trash_cset : 2124 ShenandoahPhaseTimings::degen_gc_final_update_refs_trash_cset); 2125 trash_cset_regions(); 2126 } 2127 } 2128 2129 void ShenandoahHeap::rebuild_free_set(bool concurrent) { 2130 { 2131 ShenandoahGCPhase phase(concurrent ? 2132 ShenandoahPhaseTimings::final_update_refs_rebuild_freeset : 2133 ShenandoahPhaseTimings::degen_gc_final_update_refs_rebuild_freeset); 2134 ShenandoahHeapLocker locker(lock()); 2135 _free_set->rebuild(); 2136 } 2137 } 2138 2139 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2140 print_on(st); 2141 print_heap_regions_on(st); 2142 } 2143 2144 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2145 size_t slice = r->index() / _bitmap_regions_per_slice; 2146 2147 size_t regions_from = _bitmap_regions_per_slice * slice; 2148 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2149 for (size_t g = regions_from; g < regions_to; g++) { 2150 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2151 if (skip_self && g == r->index()) continue; 2152 if (get_region(g)->is_committed()) { 2153 return true; 2154 } 2155 } 2156 return false; 2157 } 2158 2159 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2160 shenandoah_assert_heaplocked(); 2161 2162 // Bitmaps in special regions do not need commits 2163 if (_bitmap_region_special) { 2164 return true; 2165 } 2166 2167 if (is_bitmap_slice_committed(r, true)) { 2168 // Some other region from the group is already committed, meaning the bitmap 2169 // slice is already committed, we exit right away. 2170 return true; 2171 } 2172 2173 // Commit the bitmap slice: 2174 size_t slice = r->index() / _bitmap_regions_per_slice; 2175 size_t off = _bitmap_bytes_per_slice * slice; 2176 size_t len = _bitmap_bytes_per_slice; 2177 char* start = (char*) _bitmap_region.start() + off; 2178 2179 if (!os::commit_memory(start, len, false)) { 2180 return false; 2181 } 2182 2183 if (AlwaysPreTouch) { 2184 os::pretouch_memory(start, start + len, _pretouch_bitmap_page_size); 2185 } 2186 2187 return true; 2188 } 2189 2190 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2191 shenandoah_assert_heaplocked(); 2192 2193 // Bitmaps in special regions do not need uncommits 2194 if (_bitmap_region_special) { 2195 return true; 2196 } 2197 2198 if (is_bitmap_slice_committed(r, true)) { 2199 // Some other region from the group is still committed, meaning the bitmap 2200 // slice is should stay committed, exit right away. 2201 return true; 2202 } 2203 2204 // Uncommit the bitmap slice: 2205 size_t slice = r->index() / _bitmap_regions_per_slice; 2206 size_t off = _bitmap_bytes_per_slice * slice; 2207 size_t len = _bitmap_bytes_per_slice; 2208 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2209 return false; 2210 } 2211 return true; 2212 } 2213 2214 void ShenandoahHeap::safepoint_synchronize_begin() { 2215 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2216 SuspendibleThreadSet::synchronize(); 2217 } 2218 } 2219 2220 void ShenandoahHeap::safepoint_synchronize_end() { 2221 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2222 SuspendibleThreadSet::desynchronize(); 2223 } 2224 } 2225 2226 void ShenandoahHeap::entry_uncommit(double shrink_before, size_t shrink_until) { 2227 static const char *msg = "Concurrent uncommit"; 2228 ShenandoahConcurrentPhase gc_phase(msg, ShenandoahPhaseTimings::conc_uncommit, true /* log_heap_usage */); 2229 EventMark em("%s", msg); 2230 2231 op_uncommit(shrink_before, shrink_until); 2232 } 2233 2234 void ShenandoahHeap::try_inject_alloc_failure() { 2235 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2236 _inject_alloc_failure.set(); 2237 os::naked_short_sleep(1); 2238 if (cancelled_gc()) { 2239 log_info(gc)("Allocation failure was successfully injected"); 2240 } 2241 } 2242 } 2243 2244 bool ShenandoahHeap::should_inject_alloc_failure() { 2245 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2246 } 2247 2248 void ShenandoahHeap::initialize_serviceability() { 2249 _memory_pool = new ShenandoahMemoryPool(this); 2250 _cycle_memory_manager.add_pool(_memory_pool); 2251 _stw_memory_manager.add_pool(_memory_pool); 2252 } 2253 2254 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 2255 GrowableArray<GCMemoryManager*> memory_managers(2); 2256 memory_managers.append(&_cycle_memory_manager); 2257 memory_managers.append(&_stw_memory_manager); 2258 return memory_managers; 2259 } 2260 2261 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 2262 GrowableArray<MemoryPool*> memory_pools(1); 2263 memory_pools.append(_memory_pool); 2264 return memory_pools; 2265 } 2266 2267 MemoryUsage ShenandoahHeap::memory_usage() { 2268 return _memory_pool->get_memory_usage(); 2269 } 2270 2271 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2272 _heap(ShenandoahHeap::heap()), 2273 _index(0) {} 2274 2275 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2276 _heap(heap), 2277 _index(0) {} 2278 2279 void ShenandoahRegionIterator::reset() { 2280 _index = 0; 2281 } 2282 2283 bool ShenandoahRegionIterator::has_next() const { 2284 return _index < _heap->num_regions(); 2285 } 2286 2287 char ShenandoahHeap::gc_state() const { 2288 return _gc_state.raw_value(); 2289 } 2290 2291 ShenandoahLiveData* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2292 #ifdef ASSERT 2293 assert(_liveness_cache != NULL, "sanity"); 2294 assert(worker_id < _max_workers, "sanity"); 2295 for (uint i = 0; i < num_regions(); i++) { 2296 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 2297 } 2298 #endif 2299 return _liveness_cache[worker_id]; 2300 } 2301 2302 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 2303 assert(worker_id < _max_workers, "sanity"); 2304 assert(_liveness_cache != NULL, "sanity"); 2305 ShenandoahLiveData* ld = _liveness_cache[worker_id]; 2306 for (uint i = 0; i < num_regions(); i++) { 2307 ShenandoahLiveData live = ld[i]; 2308 if (live > 0) { 2309 ShenandoahHeapRegion* r = get_region(i); 2310 r->increase_live_data_gc_words(live); 2311 ld[i] = 0; 2312 } 2313 } 2314 }