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/tlab_globals.hpp" 36 37 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 38 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 39 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 40 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 41 #include "gc/shenandoah/shenandoahConcurrentMark.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.inline.hpp" 47 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 48 #include "gc/shenandoah/shenandoahInitLogger.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/shenandoahOopClosures.inline.hpp" 54 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 55 #include "gc/shenandoah/shenandoahPadding.hpp" 56 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp" 57 #include "gc/shenandoah/shenandoahReferenceProcessor.hpp" 58 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 59 #include "gc/shenandoah/shenandoahStringDedup.hpp" 60 #include "gc/shenandoah/shenandoahSTWMark.hpp" 61 #include "gc/shenandoah/shenandoahUtils.hpp" 62 #include "gc/shenandoah/shenandoahVerifier.hpp" 63 #include "gc/shenandoah/shenandoahCodeRoots.hpp" 64 #include "gc/shenandoah/shenandoahVMOperations.hpp" 65 #include "gc/shenandoah/shenandoahWorkGroup.hpp" 66 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp" 67 #include "gc/shenandoah/mode/shenandoahIUMode.hpp" 68 #include "gc/shenandoah/mode/shenandoahPassiveMode.hpp" 69 #include "gc/shenandoah/mode/shenandoahSATBMode.hpp" 70 #if INCLUDE_JFR 71 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 72 #endif 73 74 #include "classfile/systemDictionary.hpp" 75 #include "memory/classLoaderMetaspace.hpp" 76 #include "memory/metaspaceUtils.hpp" 77 #include "oops/compressedOops.inline.hpp" 78 #include "prims/jvmtiTagMap.hpp" 79 #include "runtime/atomic.hpp" 80 #include "runtime/globals.hpp" 81 #include "runtime/interfaceSupport.inline.hpp" 82 #include "runtime/java.hpp" 83 #include "runtime/orderAccess.hpp" 84 #include "runtime/safepointMechanism.hpp" 85 #include "runtime/vmThread.hpp" 86 #include "services/mallocTracker.hpp" 87 #include "services/memTracker.hpp" 88 #include "utilities/events.hpp" 89 #include "utilities/powerOfTwo.hpp" 90 91 class ShenandoahPretouchHeapTask : public WorkerTask { 92 private: 93 ShenandoahRegionIterator _regions; 94 const size_t _page_size; 95 public: 96 ShenandoahPretouchHeapTask(size_t page_size) : 97 WorkerTask("Shenandoah Pretouch Heap"), 98 _page_size(page_size) {} 99 100 virtual void work(uint worker_id) { 101 ShenandoahHeapRegion* r = _regions.next(); 102 while (r != NULL) { 103 if (r->is_committed()) { 104 os::pretouch_memory(r->bottom(), r->end(), _page_size); 105 } 106 r = _regions.next(); 107 } 108 } 109 }; 110 111 class ShenandoahPretouchBitmapTask : public WorkerTask { 112 private: 113 ShenandoahRegionIterator _regions; 114 char* _bitmap_base; 115 const size_t _bitmap_size; 116 const size_t _page_size; 117 public: 118 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 119 WorkerTask("Shenandoah Pretouch Bitmap"), 120 _bitmap_base(bitmap_base), 121 _bitmap_size(bitmap_size), 122 _page_size(page_size) {} 123 124 virtual void work(uint worker_id) { 125 ShenandoahHeapRegion* r = _regions.next(); 126 while (r != NULL) { 127 size_t start = r->index() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 128 size_t end = (r->index() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 129 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 130 131 if (r->is_committed()) { 132 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 133 } 134 135 r = _regions.next(); 136 } 137 } 138 }; 139 140 jint ShenandoahHeap::initialize() { 141 // 142 // Figure out heap sizing 143 // 144 145 size_t init_byte_size = InitialHeapSize; 146 size_t min_byte_size = MinHeapSize; 147 size_t max_byte_size = MaxHeapSize; 148 size_t heap_alignment = HeapAlignment; 149 150 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 151 152 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 153 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 154 155 _num_regions = ShenandoahHeapRegion::region_count(); 156 assert(_num_regions == (max_byte_size / reg_size_bytes), 157 "Regions should cover entire heap exactly: " SIZE_FORMAT " != " SIZE_FORMAT "/" SIZE_FORMAT, 158 _num_regions, max_byte_size, reg_size_bytes); 159 160 // Now we know the number of regions, initialize the heuristics. 161 initialize_heuristics(); 162 163 size_t num_committed_regions = init_byte_size / reg_size_bytes; 164 num_committed_regions = MIN2(num_committed_regions, _num_regions); 165 assert(num_committed_regions <= _num_regions, "sanity"); 166 _initial_size = num_committed_regions * reg_size_bytes; 167 168 size_t num_min_regions = min_byte_size / reg_size_bytes; 169 num_min_regions = MIN2(num_min_regions, _num_regions); 170 assert(num_min_regions <= _num_regions, "sanity"); 171 _minimum_size = num_min_regions * reg_size_bytes; 172 173 // Default to max heap size. 174 _soft_max_size = _num_regions * reg_size_bytes; 175 176 _committed = _initial_size; 177 178 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 179 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 180 size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 181 182 // 183 // Reserve and commit memory for heap 184 // 185 186 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 187 initialize_reserved_region(heap_rs); 188 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 189 _heap_region_special = heap_rs.special(); 190 191 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 192 "Misaligned heap: " PTR_FORMAT, p2i(base())); 193 194 #if SHENANDOAH_OPTIMIZED_MARKTASK 195 // The optimized ShenandoahMarkTask takes some bits away from the full object bits. 196 // Fail if we ever attempt to address more than we can. 197 if ((uintptr_t)heap_rs.end() >= ShenandoahMarkTask::max_addressable()) { 198 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 199 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 200 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 201 p2i(heap_rs.base()), p2i(heap_rs.end()), ShenandoahMarkTask::max_addressable()); 202 vm_exit_during_initialization("Fatal Error", buf); 203 } 204 #endif 205 206 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 207 if (!_heap_region_special) { 208 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 209 "Cannot commit heap memory"); 210 } 211 212 // 213 // Reserve and commit memory for bitmap(s) 214 // 215 216 _bitmap_size = ShenandoahMarkBitMap::compute_size(heap_rs.size()); 217 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 218 219 size_t bitmap_bytes_per_region = reg_size_bytes / ShenandoahMarkBitMap::heap_map_factor(); 220 221 guarantee(bitmap_bytes_per_region != 0, 222 "Bitmap bytes per region should not be zero"); 223 guarantee(is_power_of_2(bitmap_bytes_per_region), 224 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 225 226 if (bitmap_page_size > bitmap_bytes_per_region) { 227 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 228 _bitmap_bytes_per_slice = bitmap_page_size; 229 } else { 230 _bitmap_regions_per_slice = 1; 231 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 232 } 233 234 guarantee(_bitmap_regions_per_slice >= 1, 235 "Should have at least one region per slice: " SIZE_FORMAT, 236 _bitmap_regions_per_slice); 237 238 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 239 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 240 _bitmap_bytes_per_slice, bitmap_page_size); 241 242 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 243 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 244 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 245 _bitmap_region_special = bitmap.special(); 246 247 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 248 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 249 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 250 if (!_bitmap_region_special) { 251 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 252 "Cannot commit bitmap memory"); 253 } 254 255 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions, _max_workers); 256 257 if (ShenandoahVerify) { 258 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 259 if (!verify_bitmap.special()) { 260 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 261 "Cannot commit verification bitmap memory"); 262 } 263 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 264 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 265 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 266 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 267 } 268 269 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 270 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 271 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 272 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 273 _aux_bitmap_region_special = aux_bitmap.special(); 274 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 275 276 // 277 // Create regions and region sets 278 // 279 size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE); 280 size_t region_storage_size = align_up(region_align * _num_regions, region_page_size); 281 region_storage_size = align_up(region_storage_size, os::vm_allocation_granularity()); 282 283 ReservedSpace region_storage(region_storage_size, region_page_size); 284 MemTracker::record_virtual_memory_type(region_storage.base(), mtGC); 285 if (!region_storage.special()) { 286 os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false, 287 "Cannot commit region memory"); 288 } 289 290 // Try to fit the collection set bitmap at lower addresses. This optimizes code generation for cset checks. 291 // Go up until a sensible limit (subject to encoding constraints) and try to reserve the space there. 292 // If not successful, bite a bullet and allocate at whatever address. 293 { 294 size_t cset_align = MAX2<size_t>(os::vm_page_size(), os::vm_allocation_granularity()); 295 size_t cset_size = align_up(((size_t) sh_rs.base() + sh_rs.size()) >> ShenandoahHeapRegion::region_size_bytes_shift(), cset_align); 296 297 uintptr_t min = round_up_power_of_2(cset_align); 298 uintptr_t max = (1u << 30u); 299 300 for (uintptr_t addr = min; addr <= max; addr <<= 1u) { 301 char* req_addr = (char*)addr; 302 assert(is_aligned(req_addr, cset_align), "Should be aligned"); 303 ReservedSpace cset_rs(cset_size, cset_align, os::vm_page_size(), req_addr); 304 if (cset_rs.is_reserved()) { 305 assert(cset_rs.base() == req_addr, "Allocated where requested: " PTR_FORMAT ", " PTR_FORMAT, p2i(cset_rs.base()), addr); 306 _collection_set = new ShenandoahCollectionSet(this, cset_rs, sh_rs.base()); 307 break; 308 } 309 } 310 311 if (_collection_set == NULL) { 312 ReservedSpace cset_rs(cset_size, cset_align, os::vm_page_size()); 313 _collection_set = new ShenandoahCollectionSet(this, cset_rs, sh_rs.base()); 314 } 315 } 316 317 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 318 _free_set = new ShenandoahFreeSet(this, _num_regions); 319 320 { 321 ShenandoahHeapLocker locker(lock()); 322 323 for (size_t i = 0; i < _num_regions; i++) { 324 HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i; 325 bool is_committed = i < num_committed_regions; 326 void* loc = region_storage.base() + i * region_align; 327 328 ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed); 329 assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity"); 330 331 _marking_context->initialize_top_at_mark_start(r); 332 _regions[i] = r; 333 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 334 } 335 336 // Initialize to complete 337 _marking_context->mark_complete(); 338 339 _free_set->rebuild(); 340 } 341 342 if (AlwaysPreTouch) { 343 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 344 // before initialize() below zeroes it with initializing thread. For any given region, 345 // we touch the region and the corresponding bitmaps from the same thread. 346 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 347 348 _pretouch_heap_page_size = heap_page_size; 349 _pretouch_bitmap_page_size = bitmap_page_size; 350 351 #ifdef LINUX 352 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 353 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 354 // them into huge one. Therefore, we need to pretouch with smaller pages. 355 if (UseTransparentHugePages) { 356 _pretouch_heap_page_size = (size_t)os::vm_page_size(); 357 _pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 358 } 359 #endif 360 361 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 362 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 363 364 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, _pretouch_bitmap_page_size); 365 _workers->run_task(&bcl); 366 367 ShenandoahPretouchHeapTask hcl(_pretouch_heap_page_size); 368 _workers->run_task(&hcl); 369 } 370 371 // 372 // Initialize the rest of GC subsystems 373 // 374 375 _liveness_cache = NEW_C_HEAP_ARRAY(ShenandoahLiveData*, _max_workers, mtGC); 376 for (uint worker = 0; worker < _max_workers; worker++) { 377 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(ShenandoahLiveData, _num_regions, mtGC); 378 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(ShenandoahLiveData)); 379 } 380 381 // There should probably be Shenandoah-specific options for these, 382 // just as there are G1-specific options. 383 { 384 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set(); 385 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold 386 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent 387 } 388 389 _monitoring_support = new ShenandoahMonitoringSupport(this); 390 _phase_timings = new ShenandoahPhaseTimings(max_workers()); 391 ShenandoahCodeRoots::initialize(); 392 393 if (ShenandoahPacing) { 394 _pacer = new ShenandoahPacer(this); 395 _pacer->setup_for_idle(); 396 } else { 397 _pacer = NULL; 398 } 399 400 _control_thread = new ShenandoahControlThread(); 401 402 ShenandoahInitLogger::print(); 403 404 return JNI_OK; 405 } 406 407 void ShenandoahHeap::initialize_mode() { 408 if (ShenandoahGCMode != NULL) { 409 if (strcmp(ShenandoahGCMode, "satb") == 0) { 410 _gc_mode = new ShenandoahSATBMode(); 411 } else if (strcmp(ShenandoahGCMode, "iu") == 0) { 412 _gc_mode = new ShenandoahIUMode(); 413 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 414 _gc_mode = new ShenandoahPassiveMode(); 415 } else { 416 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 417 } 418 } else { 419 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option (null)"); 420 } 421 _gc_mode->initialize_flags(); 422 if (_gc_mode->is_diagnostic() && !UnlockDiagnosticVMOptions) { 423 vm_exit_during_initialization( 424 err_msg("GC mode \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 425 _gc_mode->name())); 426 } 427 if (_gc_mode->is_experimental() && !UnlockExperimentalVMOptions) { 428 vm_exit_during_initialization( 429 err_msg("GC mode \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 430 _gc_mode->name())); 431 } 432 } 433 434 void ShenandoahHeap::initialize_heuristics() { 435 assert(_gc_mode != NULL, "Must be initialized"); 436 _heuristics = _gc_mode->initialize_heuristics(); 437 438 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 439 vm_exit_during_initialization( 440 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 441 _heuristics->name())); 442 } 443 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 444 vm_exit_during_initialization( 445 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 446 _heuristics->name())); 447 } 448 } 449 450 #ifdef _MSC_VER 451 #pragma warning( push ) 452 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 453 #endif 454 455 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 456 CollectedHeap(), 457 _initial_size(0), 458 _used(0), 459 _committed(0), 460 _bytes_allocated_since_gc_start(0), 461 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), 462 _workers(NULL), 463 _safepoint_workers(NULL), 464 _heap_region_special(false), 465 _num_regions(0), 466 _regions(NULL), 467 _update_refs_iterator(this), 468 _control_thread(NULL), 469 _shenandoah_policy(policy), 470 _gc_mode(NULL), 471 _heuristics(NULL), 472 _free_set(NULL), 473 _pacer(NULL), 474 _verifier(NULL), 475 _phase_timings(NULL), 476 _monitoring_support(NULL), 477 _memory_pool(NULL), 478 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), 479 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), 480 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 481 _soft_ref_policy(), 482 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes), 483 _ref_processor(new ShenandoahReferenceProcessor(MAX2(_max_workers, 1U))), 484 _marking_context(NULL), 485 _bitmap_size(0), 486 _bitmap_regions_per_slice(0), 487 _bitmap_bytes_per_slice(0), 488 _bitmap_region_special(false), 489 _aux_bitmap_region_special(false), 490 _liveness_cache(NULL), 491 _collection_set(NULL) 492 { 493 // Initialize GC mode early, so we can adjust barrier support 494 initialize_mode(); 495 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); 496 497 _max_workers = MAX2(_max_workers, 1U); 498 _workers = new ShenandoahWorkerThreads("Shenandoah GC Threads", _max_workers); 499 if (_workers == NULL) { 500 vm_exit_during_initialization("Failed necessary allocation."); 501 } else { 502 _workers->initialize_workers(); 503 } 504 505 if (ParallelGCThreads > 1) { 506 _safepoint_workers = new ShenandoahWorkerThreads("Safepoint Cleanup Thread", 507 ParallelGCThreads); 508 _safepoint_workers->initialize_workers(); 509 } 510 } 511 512 #ifdef _MSC_VER 513 #pragma warning( pop ) 514 #endif 515 516 class ShenandoahResetBitmapTask : public WorkerTask { 517 private: 518 ShenandoahRegionIterator _regions; 519 520 public: 521 ShenandoahResetBitmapTask() : 522 WorkerTask("Shenandoah Reset Bitmap") {} 523 524 void work(uint worker_id) { 525 ShenandoahHeapRegion* region = _regions.next(); 526 ShenandoahHeap* heap = ShenandoahHeap::heap(); 527 ShenandoahMarkingContext* const ctx = heap->marking_context(); 528 while (region != NULL) { 529 if (heap->is_bitmap_slice_committed(region)) { 530 ctx->clear_bitmap(region); 531 } 532 region = _regions.next(); 533 } 534 } 535 }; 536 537 void ShenandoahHeap::reset_mark_bitmap() { 538 assert_gc_workers(_workers->active_workers()); 539 mark_incomplete_marking_context(); 540 541 ShenandoahResetBitmapTask task; 542 _workers->run_task(&task); 543 } 544 545 void ShenandoahHeap::print_on(outputStream* st) const { 546 st->print_cr("Shenandoah Heap"); 547 st->print_cr(" " SIZE_FORMAT "%s max, " SIZE_FORMAT "%s soft max, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 548 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 549 byte_size_in_proper_unit(soft_max_capacity()), proper_unit_for_byte_size(soft_max_capacity()), 550 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 551 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 552 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 553 num_regions(), 554 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 555 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 556 557 st->print("Status: "); 558 if (has_forwarded_objects()) st->print("has forwarded objects, "); 559 if (is_concurrent_mark_in_progress()) st->print("marking, "); 560 if (is_evacuation_in_progress()) st->print("evacuating, "); 561 if (is_update_refs_in_progress()) st->print("updating refs, "); 562 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 563 if (is_full_gc_in_progress()) st->print("full gc, "); 564 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 565 if (is_concurrent_weak_root_in_progress()) st->print("concurrent weak roots, "); 566 if (is_concurrent_strong_root_in_progress() && 567 !is_concurrent_weak_root_in_progress()) st->print("concurrent strong roots, "); 568 569 if (cancelled_gc()) { 570 st->print("cancelled"); 571 } else { 572 st->print("not cancelled"); 573 } 574 st->cr(); 575 576 st->print_cr("Reserved region:"); 577 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 578 p2i(reserved_region().start()), 579 p2i(reserved_region().end())); 580 581 ShenandoahCollectionSet* cset = collection_set(); 582 st->print_cr("Collection set:"); 583 if (cset != NULL) { 584 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 585 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 586 } else { 587 st->print_cr(" (NULL)"); 588 } 589 590 st->cr(); 591 MetaspaceUtils::print_on(st); 592 593 if (Verbose) { 594 print_heap_regions_on(st); 595 } 596 } 597 598 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 599 public: 600 void do_thread(Thread* thread) { 601 assert(thread != NULL, "Sanity"); 602 assert(thread->is_Worker_thread(), "Only worker thread expected"); 603 ShenandoahThreadLocalData::initialize_gclab(thread); 604 } 605 }; 606 607 void ShenandoahHeap::post_initialize() { 608 CollectedHeap::post_initialize(); 609 MutexLocker ml(Threads_lock); 610 611 ShenandoahInitWorkerGCLABClosure init_gclabs; 612 _workers->threads_do(&init_gclabs); 613 614 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 615 // Now, we will let WorkerThreads to initialize gclab when new worker is created. 616 _workers->set_initialize_gclab(); 617 if (_safepoint_workers != NULL) { 618 _safepoint_workers->threads_do(&init_gclabs); 619 _safepoint_workers->set_initialize_gclab(); 620 } 621 622 _heuristics->initialize(); 623 624 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 625 } 626 627 size_t ShenandoahHeap::used() const { 628 return Atomic::load(&_used); 629 } 630 631 size_t ShenandoahHeap::committed() const { 632 return Atomic::load(&_committed); 633 } 634 635 void ShenandoahHeap::increase_committed(size_t bytes) { 636 shenandoah_assert_heaplocked_or_safepoint(); 637 _committed += bytes; 638 } 639 640 void ShenandoahHeap::decrease_committed(size_t bytes) { 641 shenandoah_assert_heaplocked_or_safepoint(); 642 _committed -= bytes; 643 } 644 645 void ShenandoahHeap::increase_used(size_t bytes) { 646 Atomic::add(&_used, bytes, memory_order_relaxed); 647 } 648 649 void ShenandoahHeap::set_used(size_t bytes) { 650 Atomic::store(&_used, bytes); 651 } 652 653 void ShenandoahHeap::decrease_used(size_t bytes) { 654 assert(used() >= bytes, "never decrease heap size by more than we've left"); 655 Atomic::sub(&_used, bytes, memory_order_relaxed); 656 } 657 658 void ShenandoahHeap::increase_allocated(size_t bytes) { 659 Atomic::add(&_bytes_allocated_since_gc_start, bytes, memory_order_relaxed); 660 } 661 662 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 663 size_t bytes = words * HeapWordSize; 664 if (!waste) { 665 increase_used(bytes); 666 } 667 increase_allocated(bytes); 668 if (ShenandoahPacing) { 669 control_thread()->pacing_notify_alloc(words); 670 if (waste) { 671 pacer()->claim_for_alloc(words, true); 672 } 673 } 674 } 675 676 size_t ShenandoahHeap::capacity() const { 677 return committed(); 678 } 679 680 size_t ShenandoahHeap::max_capacity() const { 681 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 682 } 683 684 size_t ShenandoahHeap::soft_max_capacity() const { 685 size_t v = Atomic::load(&_soft_max_size); 686 assert(min_capacity() <= v && v <= max_capacity(), 687 "Should be in bounds: " SIZE_FORMAT " <= " SIZE_FORMAT " <= " SIZE_FORMAT, 688 min_capacity(), v, max_capacity()); 689 return v; 690 } 691 692 void ShenandoahHeap::set_soft_max_capacity(size_t v) { 693 assert(min_capacity() <= v && v <= max_capacity(), 694 "Should be in bounds: " SIZE_FORMAT " <= " SIZE_FORMAT " <= " SIZE_FORMAT, 695 min_capacity(), v, max_capacity()); 696 Atomic::store(&_soft_max_size, v); 697 } 698 699 size_t ShenandoahHeap::min_capacity() const { 700 return _minimum_size; 701 } 702 703 size_t ShenandoahHeap::initial_capacity() const { 704 return _initial_size; 705 } 706 707 bool ShenandoahHeap::is_in(const void* p) const { 708 HeapWord* heap_base = (HeapWord*) base(); 709 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 710 return p >= heap_base && p < last_region_end; 711 } 712 713 void ShenandoahHeap::op_uncommit(double shrink_before, size_t shrink_until) { 714 assert (ShenandoahUncommit, "should be enabled"); 715 716 // Application allocates from the beginning of the heap, and GC allocates at 717 // the end of it. It is more efficient to uncommit from the end, so that applications 718 // could enjoy the near committed regions. GC allocations are much less frequent, 719 // and therefore can accept the committing costs. 720 721 size_t count = 0; 722 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 723 ShenandoahHeapRegion* r = get_region(i - 1); 724 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 725 ShenandoahHeapLocker locker(lock()); 726 if (r->is_empty_committed()) { 727 if (committed() < shrink_until + ShenandoahHeapRegion::region_size_bytes()) { 728 break; 729 } 730 731 r->make_uncommitted(); 732 count++; 733 } 734 } 735 SpinPause(); // allow allocators to take the lock 736 } 737 738 if (count > 0) { 739 control_thread()->notify_heap_changed(); 740 } 741 } 742 743 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 744 // New object should fit the GCLAB size 745 size_t min_size = MAX2(size, PLAB::min_size()); 746 747 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 748 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 749 new_size = MIN2(new_size, PLAB::max_size()); 750 new_size = MAX2(new_size, PLAB::min_size()); 751 752 // Record new heuristic value even if we take any shortcut. This captures 753 // the case when moderately-sized objects always take a shortcut. At some point, 754 // heuristics should catch up with them. 755 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 756 757 if (new_size < size) { 758 // New size still does not fit the object. Fall back to shared allocation. 759 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 760 return NULL; 761 } 762 763 // Retire current GCLAB, and allocate a new one. 764 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 765 gclab->retire(); 766 767 size_t actual_size = 0; 768 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 769 if (gclab_buf == NULL) { 770 return NULL; 771 } 772 773 assert (size <= actual_size, "allocation should fit"); 774 775 if (ZeroTLAB) { 776 // ..and clear it. 777 Copy::zero_to_words(gclab_buf, actual_size); 778 } else { 779 // ...and zap just allocated object. 780 #ifdef ASSERT 781 // Skip mangling the space corresponding to the object header to 782 // ensure that the returned space is not considered parsable by 783 // any concurrent GC thread. 784 size_t hdr_size = oopDesc::header_size(); 785 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 786 #endif // ASSERT 787 } 788 gclab->set_buf(gclab_buf, actual_size); 789 return gclab->allocate(size); 790 } 791 792 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 793 size_t requested_size, 794 size_t* actual_size) { 795 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 796 HeapWord* res = allocate_memory(req); 797 if (res != NULL) { 798 *actual_size = req.actual_size(); 799 } else { 800 *actual_size = 0; 801 } 802 return res; 803 } 804 805 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 806 size_t word_size, 807 size_t* actual_size) { 808 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 809 HeapWord* res = allocate_memory(req); 810 if (res != NULL) { 811 *actual_size = req.actual_size(); 812 } else { 813 *actual_size = 0; 814 } 815 return res; 816 } 817 818 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 819 intptr_t pacer_epoch = 0; 820 bool in_new_region = false; 821 HeapWord* result = NULL; 822 823 if (req.is_mutator_alloc()) { 824 if (ShenandoahPacing) { 825 pacer()->pace_for_alloc(req.size()); 826 pacer_epoch = pacer()->epoch(); 827 } 828 829 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 830 result = allocate_memory_under_lock(req, in_new_region); 831 } 832 833 // Allocation failed, block until control thread reacted, then retry allocation. 834 // 835 // It might happen that one of the threads requesting allocation would unblock 836 // way later after GC happened, only to fail the second allocation, because 837 // other threads have already depleted the free storage. In this case, a better 838 // strategy is to try again, as long as GC makes progress. 839 // 840 // Then, we need to make sure the allocation was retried after at least one 841 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 842 843 size_t tries = 0; 844 845 while (result == NULL && _progress_last_gc.is_set()) { 846 tries++; 847 control_thread()->handle_alloc_failure(req); 848 result = allocate_memory_under_lock(req, in_new_region); 849 } 850 851 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 852 tries++; 853 control_thread()->handle_alloc_failure(req); 854 result = allocate_memory_under_lock(req, in_new_region); 855 } 856 857 } else { 858 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 859 result = allocate_memory_under_lock(req, in_new_region); 860 // Do not call handle_alloc_failure() here, because we cannot block. 861 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 862 } 863 864 if (in_new_region) { 865 control_thread()->notify_heap_changed(); 866 } 867 868 if (result != NULL) { 869 size_t requested = req.size(); 870 size_t actual = req.actual_size(); 871 872 assert (req.is_lab_alloc() || (requested == actual), 873 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 874 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 875 876 if (req.is_mutator_alloc()) { 877 notify_mutator_alloc_words(actual, false); 878 879 // If we requested more than we were granted, give the rest back to pacer. 880 // This only matters if we are in the same pacing epoch: do not try to unpace 881 // over the budget for the other phase. 882 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 883 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 884 } 885 } else { 886 increase_used(actual*HeapWordSize); 887 } 888 } 889 890 return result; 891 } 892 893 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 894 ShenandoahHeapLocker locker(lock()); 895 return _free_set->allocate(req, in_new_region); 896 } 897 898 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 899 bool* gc_overhead_limit_was_exceeded) { 900 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 901 return allocate_memory(req); 902 } 903 904 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 905 size_t size, 906 Metaspace::MetadataType mdtype) { 907 MetaWord* result; 908 909 // Inform metaspace OOM to GC heuristics if class unloading is possible. 910 if (heuristics()->can_unload_classes()) { 911 ShenandoahHeuristics* h = heuristics(); 912 h->record_metaspace_oom(); 913 } 914 915 // Expand and retry allocation 916 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 917 if (result != NULL) { 918 return result; 919 } 920 921 // Start full GC 922 collect(GCCause::_metadata_GC_clear_soft_refs); 923 924 // Retry allocation 925 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 926 if (result != NULL) { 927 return result; 928 } 929 930 // Expand and retry allocation 931 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 932 if (result != NULL) { 933 return result; 934 } 935 936 // Out of memory 937 return NULL; 938 } 939 940 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 941 private: 942 ShenandoahHeap* const _heap; 943 Thread* const _thread; 944 public: 945 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 946 _heap(heap), _thread(Thread::current()) {} 947 948 void do_object(oop p) { 949 shenandoah_assert_marked(NULL, p); 950 if (!p->is_forwarded()) { 951 _heap->evacuate_object(p, _thread); 952 } 953 } 954 }; 955 956 class ShenandoahEvacuationTask : public WorkerTask { 957 private: 958 ShenandoahHeap* const _sh; 959 ShenandoahCollectionSet* const _cs; 960 bool _concurrent; 961 public: 962 ShenandoahEvacuationTask(ShenandoahHeap* sh, 963 ShenandoahCollectionSet* cs, 964 bool concurrent) : 965 WorkerTask("Shenandoah Evacuation"), 966 _sh(sh), 967 _cs(cs), 968 _concurrent(concurrent) 969 {} 970 971 void work(uint worker_id) { 972 if (_concurrent) { 973 ShenandoahConcurrentWorkerSession worker_session(worker_id); 974 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 975 ShenandoahEvacOOMScope oom_evac_scope; 976 do_work(); 977 } else { 978 ShenandoahParallelWorkerSession worker_session(worker_id); 979 ShenandoahEvacOOMScope oom_evac_scope; 980 do_work(); 981 } 982 } 983 984 private: 985 void do_work() { 986 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 987 ShenandoahHeapRegion* r; 988 while ((r =_cs->claim_next()) != NULL) { 989 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->index()); 990 _sh->marked_object_iterate(r, &cl); 991 992 if (ShenandoahPacing) { 993 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 994 } 995 996 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 997 break; 998 } 999 } 1000 } 1001 }; 1002 1003 void ShenandoahHeap::evacuate_collection_set(bool concurrent) { 1004 ShenandoahEvacuationTask task(this, _collection_set, concurrent); 1005 workers()->run_task(&task); 1006 } 1007 1008 void ShenandoahHeap::trash_cset_regions() { 1009 ShenandoahHeapLocker locker(lock()); 1010 1011 ShenandoahCollectionSet* set = collection_set(); 1012 ShenandoahHeapRegion* r; 1013 set->clear_current_index(); 1014 while ((r = set->next()) != NULL) { 1015 r->make_trash(); 1016 } 1017 collection_set()->clear(); 1018 } 1019 1020 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 1021 st->print_cr("Heap Regions:"); 1022 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 1023 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 1024 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark"); 1025 st->print_cr("SN=alloc sequence number"); 1026 1027 for (size_t i = 0; i < num_regions(); i++) { 1028 get_region(i)->print_on(st); 1029 } 1030 } 1031 1032 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 1033 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1034 1035 oop humongous_obj = cast_to_oop(start->bottom()); 1036 size_t size = humongous_obj->size(); 1037 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1038 size_t index = start->index() + required_regions - 1; 1039 1040 assert(!start->has_live(), "liveness must be zero"); 1041 1042 for(size_t i = 0; i < required_regions; i++) { 1043 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1044 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1045 ShenandoahHeapRegion* region = get_region(index --); 1046 1047 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1048 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1049 1050 region->make_trash_immediate(); 1051 } 1052 } 1053 1054 class ShenandoahCheckCleanGCLABClosure : public ThreadClosure { 1055 public: 1056 ShenandoahCheckCleanGCLABClosure() {} 1057 void do_thread(Thread* thread) { 1058 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1059 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1060 assert(gclab->words_remaining() == 0, "GCLAB should not need retirement"); 1061 } 1062 }; 1063 1064 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1065 private: 1066 bool const _resize; 1067 public: 1068 ShenandoahRetireGCLABClosure(bool resize) : _resize(resize) {} 1069 void do_thread(Thread* thread) { 1070 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1071 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1072 gclab->retire(); 1073 if (_resize && ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1074 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1075 } 1076 } 1077 }; 1078 1079 void ShenandoahHeap::labs_make_parsable() { 1080 assert(UseTLAB, "Only call with UseTLAB"); 1081 1082 ShenandoahRetireGCLABClosure cl(false); 1083 1084 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1085 ThreadLocalAllocBuffer& tlab = t->tlab(); 1086 tlab.make_parsable(); 1087 cl.do_thread(t); 1088 } 1089 1090 workers()->threads_do(&cl); 1091 } 1092 1093 void ShenandoahHeap::tlabs_retire(bool resize) { 1094 assert(UseTLAB, "Only call with UseTLAB"); 1095 assert(!resize || ResizeTLAB, "Only call for resize when ResizeTLAB is enabled"); 1096 1097 ThreadLocalAllocStats stats; 1098 1099 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1100 ThreadLocalAllocBuffer& tlab = t->tlab(); 1101 tlab.retire(&stats); 1102 if (resize) { 1103 tlab.resize(); 1104 } 1105 } 1106 1107 stats.publish(); 1108 1109 #ifdef ASSERT 1110 ShenandoahCheckCleanGCLABClosure cl; 1111 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1112 cl.do_thread(t); 1113 } 1114 workers()->threads_do(&cl); 1115 #endif 1116 } 1117 1118 void ShenandoahHeap::gclabs_retire(bool resize) { 1119 assert(UseTLAB, "Only call with UseTLAB"); 1120 assert(!resize || ResizeTLAB, "Only call for resize when ResizeTLAB is enabled"); 1121 1122 ShenandoahRetireGCLABClosure cl(resize); 1123 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1124 cl.do_thread(t); 1125 } 1126 workers()->threads_do(&cl); 1127 1128 if (safepoint_workers() != NULL) { 1129 safepoint_workers()->threads_do(&cl); 1130 } 1131 } 1132 1133 // Returns size in bytes 1134 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1135 if (ShenandoahElasticTLAB) { 1136 // With Elastic TLABs, return the max allowed size, and let the allocation path 1137 // figure out the safe size for current allocation. 1138 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1139 } else { 1140 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1141 } 1142 } 1143 1144 size_t ShenandoahHeap::max_tlab_size() const { 1145 // Returns size in words 1146 return ShenandoahHeapRegion::max_tlab_size_words(); 1147 } 1148 1149 void ShenandoahHeap::collect(GCCause::Cause cause) { 1150 control_thread()->request_gc(cause); 1151 } 1152 1153 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1154 //assert(false, "Shouldn't need to do full collections"); 1155 } 1156 1157 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1158 ShenandoahHeapRegion* r = heap_region_containing(addr); 1159 if (r != NULL) { 1160 return r->block_start(addr); 1161 } 1162 return NULL; 1163 } 1164 1165 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1166 ShenandoahHeapRegion* r = heap_region_containing(addr); 1167 return r->block_is_obj(addr); 1168 } 1169 1170 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const { 1171 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr); 1172 } 1173 1174 void ShenandoahHeap::prepare_for_verify() { 1175 if (SafepointSynchronize::is_at_safepoint() && UseTLAB) { 1176 labs_make_parsable(); 1177 } 1178 } 1179 1180 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1181 workers()->threads_do(tcl); 1182 if (_safepoint_workers != NULL) { 1183 _safepoint_workers->threads_do(tcl); 1184 } 1185 if (ShenandoahStringDedup::is_enabled()) { 1186 ShenandoahStringDedup::threads_do(tcl); 1187 } 1188 } 1189 1190 void ShenandoahHeap::print_tracing_info() const { 1191 LogTarget(Info, gc, stats) lt; 1192 if (lt.is_enabled()) { 1193 ResourceMark rm; 1194 LogStream ls(lt); 1195 1196 phase_timings()->print_global_on(&ls); 1197 1198 ls.cr(); 1199 ls.cr(); 1200 1201 shenandoah_policy()->print_gc_stats(&ls); 1202 1203 ls.cr(); 1204 ls.cr(); 1205 } 1206 } 1207 1208 void ShenandoahHeap::verify(VerifyOption vo) { 1209 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1210 if (ShenandoahVerify) { 1211 verifier()->verify_generic(vo); 1212 } else { 1213 // TODO: Consider allocating verification bitmaps on demand, 1214 // and turn this on unconditionally. 1215 } 1216 } 1217 } 1218 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1219 return _free_set->capacity(); 1220 } 1221 1222 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1223 private: 1224 MarkBitMap* _bitmap; 1225 ShenandoahScanObjectStack* _oop_stack; 1226 ShenandoahHeap* const _heap; 1227 ShenandoahMarkingContext* const _marking_context; 1228 1229 template <class T> 1230 void do_oop_work(T* p) { 1231 T o = RawAccess<>::oop_load(p); 1232 if (!CompressedOops::is_null(o)) { 1233 oop obj = CompressedOops::decode_not_null(o); 1234 if (_heap->is_concurrent_weak_root_in_progress() && !_marking_context->is_marked(obj)) { 1235 // There may be dead oops in weak roots in concurrent root phase, do not touch them. 1236 return; 1237 } 1238 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1239 1240 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1241 if (!_bitmap->is_marked(obj)) { 1242 _bitmap->mark(obj); 1243 _oop_stack->push(obj); 1244 } 1245 } 1246 } 1247 public: 1248 ObjectIterateScanRootClosure(MarkBitMap* bitmap, ShenandoahScanObjectStack* oop_stack) : 1249 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()), 1250 _marking_context(_heap->marking_context()) {} 1251 void do_oop(oop* p) { do_oop_work(p); } 1252 void do_oop(narrowOop* p) { do_oop_work(p); } 1253 }; 1254 1255 /* 1256 * This is public API, used in preparation of object_iterate(). 1257 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1258 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1259 * control, we call SH::tlabs_retire, SH::gclabs_retire. 1260 */ 1261 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1262 // No-op. 1263 } 1264 1265 /* 1266 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1267 * 1268 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1269 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1270 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1271 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1272 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1273 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1274 * wiped the bitmap in preparation for next marking). 1275 * 1276 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1277 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1278 * is allowed to report dead objects, but is not required to do so. 1279 */ 1280 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1281 // Reset bitmap 1282 if (!prepare_aux_bitmap_for_iteration()) 1283 return; 1284 1285 ShenandoahScanObjectStack oop_stack; 1286 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1287 // Seed the stack with root scan 1288 scan_roots_for_iteration(&oop_stack, &oops); 1289 1290 // Work through the oop stack to traverse heap 1291 while (! oop_stack.is_empty()) { 1292 oop obj = oop_stack.pop(); 1293 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1294 cl->do_object(obj); 1295 obj->oop_iterate(&oops); 1296 } 1297 1298 assert(oop_stack.is_empty(), "should be empty"); 1299 // Reclaim bitmap 1300 reclaim_aux_bitmap_for_iteration(); 1301 } 1302 1303 bool ShenandoahHeap::prepare_aux_bitmap_for_iteration() { 1304 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1305 1306 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1307 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1308 return false; 1309 } 1310 // Reset bitmap 1311 _aux_bit_map.clear(); 1312 return true; 1313 } 1314 1315 void ShenandoahHeap::scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops) { 1316 // Process GC roots according to current GC cycle 1317 // This populates the work stack with initial objects 1318 // It is important to relinquish the associated locks before diving 1319 // into heap dumper 1320 uint n_workers = safepoint_workers() != NULL ? safepoint_workers()->active_workers() : 1; 1321 ShenandoahHeapIterationRootScanner rp(n_workers); 1322 rp.roots_do(oops); 1323 } 1324 1325 void ShenandoahHeap::reclaim_aux_bitmap_for_iteration() { 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 // Closure for parallelly iterate objects 1332 class ShenandoahObjectIterateParScanClosure : public BasicOopIterateClosure { 1333 private: 1334 MarkBitMap* _bitmap; 1335 ShenandoahObjToScanQueue* _queue; 1336 ShenandoahHeap* const _heap; 1337 ShenandoahMarkingContext* const _marking_context; 1338 1339 template <class T> 1340 void do_oop_work(T* p) { 1341 T o = RawAccess<>::oop_load(p); 1342 if (!CompressedOops::is_null(o)) { 1343 oop obj = CompressedOops::decode_not_null(o); 1344 if (_heap->is_concurrent_weak_root_in_progress() && !_marking_context->is_marked(obj)) { 1345 // There may be dead oops in weak roots in concurrent root phase, do not touch them. 1346 return; 1347 } 1348 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1349 1350 assert(oopDesc::is_oop(obj), "Must be a valid oop"); 1351 if (_bitmap->par_mark(obj)) { 1352 _queue->push(ShenandoahMarkTask(obj)); 1353 } 1354 } 1355 } 1356 public: 1357 ShenandoahObjectIterateParScanClosure(MarkBitMap* bitmap, ShenandoahObjToScanQueue* q) : 1358 _bitmap(bitmap), _queue(q), _heap(ShenandoahHeap::heap()), 1359 _marking_context(_heap->marking_context()) {} 1360 void do_oop(oop* p) { do_oop_work(p); } 1361 void do_oop(narrowOop* p) { do_oop_work(p); } 1362 }; 1363 1364 // Object iterator for parallel heap iteraion. 1365 // The root scanning phase happenes in construction as a preparation of 1366 // parallel marking queues. 1367 // Every worker processes it's own marking queue. work-stealing is used 1368 // to balance workload. 1369 class ShenandoahParallelObjectIterator : public ParallelObjectIteratorImpl { 1370 private: 1371 uint _num_workers; 1372 bool _init_ready; 1373 MarkBitMap* _aux_bit_map; 1374 ShenandoahHeap* _heap; 1375 ShenandoahScanObjectStack _roots_stack; // global roots stack 1376 ShenandoahObjToScanQueueSet* _task_queues; 1377 public: 1378 ShenandoahParallelObjectIterator(uint num_workers, MarkBitMap* bitmap) : 1379 _num_workers(num_workers), 1380 _init_ready(false), 1381 _aux_bit_map(bitmap), 1382 _heap(ShenandoahHeap::heap()) { 1383 // Initialize bitmap 1384 _init_ready = _heap->prepare_aux_bitmap_for_iteration(); 1385 if (!_init_ready) { 1386 return; 1387 } 1388 1389 ObjectIterateScanRootClosure oops(_aux_bit_map, &_roots_stack); 1390 _heap->scan_roots_for_iteration(&_roots_stack, &oops); 1391 1392 _init_ready = prepare_worker_queues(); 1393 } 1394 1395 ~ShenandoahParallelObjectIterator() { 1396 // Reclaim bitmap 1397 _heap->reclaim_aux_bitmap_for_iteration(); 1398 // Reclaim queue for workers 1399 if (_task_queues!= NULL) { 1400 for (uint i = 0; i < _num_workers; ++i) { 1401 ShenandoahObjToScanQueue* q = _task_queues->queue(i); 1402 if (q != NULL) { 1403 delete q; 1404 _task_queues->register_queue(i, NULL); 1405 } 1406 } 1407 delete _task_queues; 1408 _task_queues = NULL; 1409 } 1410 } 1411 1412 virtual void object_iterate(ObjectClosure* cl, uint worker_id) { 1413 if (_init_ready) { 1414 object_iterate_parallel(cl, worker_id, _task_queues); 1415 } 1416 } 1417 1418 private: 1419 // Divide global root_stack into worker queues 1420 bool prepare_worker_queues() { 1421 _task_queues = new ShenandoahObjToScanQueueSet((int) _num_workers); 1422 // Initialize queues for every workers 1423 for (uint i = 0; i < _num_workers; ++i) { 1424 ShenandoahObjToScanQueue* task_queue = new ShenandoahObjToScanQueue(); 1425 _task_queues->register_queue(i, task_queue); 1426 } 1427 // Divide roots among the workers. Assume that object referencing distribution 1428 // is related with root kind, use round-robin to make every worker have same chance 1429 // to process every kind of roots 1430 size_t roots_num = _roots_stack.size(); 1431 if (roots_num == 0) { 1432 // No work to do 1433 return false; 1434 } 1435 1436 for (uint j = 0; j < roots_num; j++) { 1437 uint stack_id = j % _num_workers; 1438 oop obj = _roots_stack.pop(); 1439 _task_queues->queue(stack_id)->push(ShenandoahMarkTask(obj)); 1440 } 1441 return true; 1442 } 1443 1444 void object_iterate_parallel(ObjectClosure* cl, 1445 uint worker_id, 1446 ShenandoahObjToScanQueueSet* queue_set) { 1447 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1448 assert(queue_set != NULL, "task queue must not be NULL"); 1449 1450 ShenandoahObjToScanQueue* q = queue_set->queue(worker_id); 1451 assert(q != NULL, "object iterate queue must not be NULL"); 1452 1453 ShenandoahMarkTask t; 1454 ShenandoahObjectIterateParScanClosure oops(_aux_bit_map, q); 1455 1456 // Work through the queue to traverse heap. 1457 // Steal when there is no task in queue. 1458 while (q->pop(t) || queue_set->steal(worker_id, t)) { 1459 oop obj = t.obj(); 1460 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1461 cl->do_object(obj); 1462 obj->oop_iterate(&oops); 1463 } 1464 assert(q->is_empty(), "should be empty"); 1465 } 1466 }; 1467 1468 ParallelObjectIteratorImpl* ShenandoahHeap::parallel_object_iterator(uint workers) { 1469 return new ShenandoahParallelObjectIterator(workers, &_aux_bit_map); 1470 } 1471 1472 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 1473 void ShenandoahHeap::keep_alive(oop obj) { 1474 if (is_concurrent_mark_in_progress() && (obj != NULL)) { 1475 ShenandoahBarrierSet::barrier_set()->enqueue(obj); 1476 } 1477 } 1478 1479 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1480 for (size_t i = 0; i < num_regions(); i++) { 1481 ShenandoahHeapRegion* current = get_region(i); 1482 blk->heap_region_do(current); 1483 } 1484 } 1485 1486 class ShenandoahParallelHeapRegionTask : public WorkerTask { 1487 private: 1488 ShenandoahHeap* const _heap; 1489 ShenandoahHeapRegionClosure* const _blk; 1490 1491 shenandoah_padding(0); 1492 volatile size_t _index; 1493 shenandoah_padding(1); 1494 1495 public: 1496 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1497 WorkerTask("Shenandoah Parallel Region Operation"), 1498 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1499 1500 void work(uint worker_id) { 1501 ShenandoahParallelWorkerSession worker_session(worker_id); 1502 size_t stride = ShenandoahParallelRegionStride; 1503 1504 size_t max = _heap->num_regions(); 1505 while (Atomic::load(&_index) < max) { 1506 size_t cur = Atomic::fetch_and_add(&_index, stride, memory_order_relaxed); 1507 size_t start = cur; 1508 size_t end = MIN2(cur + stride, max); 1509 if (start >= max) break; 1510 1511 for (size_t i = cur; i < end; i++) { 1512 ShenandoahHeapRegion* current = _heap->get_region(i); 1513 _blk->heap_region_do(current); 1514 } 1515 } 1516 } 1517 }; 1518 1519 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1520 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1521 if (num_regions() > ShenandoahParallelRegionStride) { 1522 ShenandoahParallelHeapRegionTask task(blk); 1523 workers()->run_task(&task); 1524 } else { 1525 heap_region_iterate(blk); 1526 } 1527 } 1528 1529 class ShenandoahInitMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1530 private: 1531 ShenandoahMarkingContext* const _ctx; 1532 public: 1533 ShenandoahInitMarkUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1534 1535 void heap_region_do(ShenandoahHeapRegion* r) { 1536 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1537 if (r->is_active()) { 1538 // Check if region needs updating its TAMS. We have updated it already during concurrent 1539 // reset, so it is very likely we don't need to do another write here. 1540 if (_ctx->top_at_mark_start(r) != r->top()) { 1541 _ctx->capture_top_at_mark_start(r); 1542 } 1543 } else { 1544 assert(_ctx->top_at_mark_start(r) == r->top(), 1545 "Region " SIZE_FORMAT " should already have correct TAMS", r->index()); 1546 } 1547 } 1548 1549 bool is_thread_safe() { return true; } 1550 }; 1551 1552 class ShenandoahRendezvousClosure : public HandshakeClosure { 1553 public: 1554 inline ShenandoahRendezvousClosure() : HandshakeClosure("ShenandoahRendezvous") {} 1555 inline void do_thread(Thread* thread) {} 1556 }; 1557 1558 void ShenandoahHeap::rendezvous_threads() { 1559 ShenandoahRendezvousClosure cl; 1560 Handshake::execute(&cl); 1561 } 1562 1563 void ShenandoahHeap::recycle_trash() { 1564 free_set()->recycle_trash(); 1565 } 1566 1567 class ShenandoahResetUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1568 private: 1569 ShenandoahMarkingContext* const _ctx; 1570 public: 1571 ShenandoahResetUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1572 1573 void heap_region_do(ShenandoahHeapRegion* r) { 1574 if (r->is_active()) { 1575 // Reset live data and set TAMS optimistically. We would recheck these under the pause 1576 // anyway to capture any updates that happened since now. 1577 r->clear_live_data(); 1578 _ctx->capture_top_at_mark_start(r); 1579 } 1580 } 1581 1582 bool is_thread_safe() { return true; } 1583 }; 1584 1585 void ShenandoahHeap::prepare_gc() { 1586 reset_mark_bitmap(); 1587 1588 ShenandoahResetUpdateRegionStateClosure cl; 1589 parallel_heap_region_iterate(&cl); 1590 } 1591 1592 class ShenandoahFinalMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1593 private: 1594 ShenandoahMarkingContext* const _ctx; 1595 ShenandoahHeapLock* const _lock; 1596 1597 public: 1598 ShenandoahFinalMarkUpdateRegionStateClosure() : 1599 _ctx(ShenandoahHeap::heap()->complete_marking_context()), _lock(ShenandoahHeap::heap()->lock()) {} 1600 1601 void heap_region_do(ShenandoahHeapRegion* r) { 1602 if (r->is_active()) { 1603 // All allocations past TAMS are implicitly live, adjust the region data. 1604 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1605 HeapWord *tams = _ctx->top_at_mark_start(r); 1606 HeapWord *top = r->top(); 1607 if (top > tams) { 1608 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1609 } 1610 1611 // We are about to select the collection set, make sure it knows about 1612 // current pinning status. Also, this allows trashing more regions that 1613 // now have their pinning status dropped. 1614 if (r->is_pinned()) { 1615 if (r->pin_count() == 0) { 1616 ShenandoahHeapLocker locker(_lock); 1617 r->make_unpinned(); 1618 } 1619 } else { 1620 if (r->pin_count() > 0) { 1621 ShenandoahHeapLocker locker(_lock); 1622 r->make_pinned(); 1623 } 1624 } 1625 1626 // Remember limit for updating refs. It's guaranteed that we get no 1627 // from-space-refs written from here on. 1628 r->set_update_watermark_at_safepoint(r->top()); 1629 } else { 1630 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1631 assert(_ctx->top_at_mark_start(r) == r->top(), 1632 "Region " SIZE_FORMAT " should have correct TAMS", r->index()); 1633 } 1634 } 1635 1636 bool is_thread_safe() { return true; } 1637 }; 1638 1639 void ShenandoahHeap::prepare_regions_and_collection_set(bool concurrent) { 1640 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 1641 { 1642 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_update_region_states : 1643 ShenandoahPhaseTimings::degen_gc_final_update_region_states); 1644 ShenandoahFinalMarkUpdateRegionStateClosure cl; 1645 parallel_heap_region_iterate(&cl); 1646 1647 assert_pinned_region_status(); 1648 } 1649 1650 { 1651 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::choose_cset : 1652 ShenandoahPhaseTimings::degen_gc_choose_cset); 1653 ShenandoahHeapLocker locker(lock()); 1654 _collection_set->clear(); 1655 heuristics()->choose_collection_set(_collection_set); 1656 } 1657 1658 { 1659 ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_rebuild_freeset : 1660 ShenandoahPhaseTimings::degen_gc_final_rebuild_freeset); 1661 ShenandoahHeapLocker locker(lock()); 1662 _free_set->rebuild(); 1663 } 1664 } 1665 1666 void ShenandoahHeap::do_class_unloading() { 1667 _unloader.unload(); 1668 } 1669 1670 void ShenandoahHeap::stw_weak_refs(bool full_gc) { 1671 // Weak refs processing 1672 ShenandoahPhaseTimings::Phase phase = full_gc ? ShenandoahPhaseTimings::full_gc_weakrefs 1673 : ShenandoahPhaseTimings::degen_gc_weakrefs; 1674 ShenandoahTimingsTracker t(phase); 1675 ShenandoahGCWorkerPhase worker_phase(phase); 1676 ref_processor()->process_references(phase, workers(), false /* concurrent */); 1677 } 1678 1679 void ShenandoahHeap::prepare_update_heap_references(bool concurrent) { 1680 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 1681 1682 // Evacuation is over, no GCLABs are needed anymore. GCLABs are under URWM, so we need to 1683 // make them parsable for update code to work correctly. Plus, we can compute new sizes 1684 // for future GCLABs here. 1685 if (UseTLAB) { 1686 ShenandoahGCPhase phase(concurrent ? 1687 ShenandoahPhaseTimings::init_update_refs_manage_gclabs : 1688 ShenandoahPhaseTimings::degen_gc_init_update_refs_manage_gclabs); 1689 gclabs_retire(ResizeTLAB); 1690 } 1691 1692 _update_refs_iterator.reset(); 1693 } 1694 1695 void ShenandoahHeap::set_gc_state_all_threads(char state) { 1696 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1697 ShenandoahThreadLocalData::set_gc_state(t, state); 1698 } 1699 } 1700 1701 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1702 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1703 _gc_state.set_cond(mask, value); 1704 set_gc_state_all_threads(_gc_state.raw_value()); 1705 } 1706 1707 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1708 assert(!has_forwarded_objects(), "Not expected before/after mark phase"); 1709 set_gc_state_mask(MARKING, in_progress); 1710 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1711 } 1712 1713 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1714 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1715 set_gc_state_mask(EVACUATION, in_progress); 1716 } 1717 1718 void ShenandoahHeap::set_concurrent_strong_root_in_progress(bool in_progress) { 1719 if (in_progress) { 1720 _concurrent_strong_root_in_progress.set(); 1721 } else { 1722 _concurrent_strong_root_in_progress.unset(); 1723 } 1724 } 1725 1726 void ShenandoahHeap::set_concurrent_weak_root_in_progress(bool cond) { 1727 set_gc_state_mask(WEAK_ROOTS, cond); 1728 } 1729 1730 GCTracer* ShenandoahHeap::tracer() { 1731 return shenandoah_policy()->tracer(); 1732 } 1733 1734 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1735 return _free_set->used(); 1736 } 1737 1738 bool ShenandoahHeap::try_cancel_gc() { 1739 while (true) { 1740 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 1741 if (prev == CANCELLABLE) return true; 1742 else if (prev == CANCELLED) return false; 1743 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 1744 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 1745 Thread* thread = Thread::current(); 1746 if (thread->is_Java_thread()) { 1747 // We need to provide a safepoint here, otherwise we might 1748 // spin forever if a SP is pending. 1749 ThreadBlockInVM sp(JavaThread::cast(thread)); 1750 SpinPause(); 1751 } 1752 } 1753 } 1754 1755 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 1756 if (try_cancel_gc()) { 1757 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 1758 log_info(gc)("%s", msg.buffer()); 1759 Events::log(Thread::current(), "%s", msg.buffer()); 1760 } 1761 } 1762 1763 uint ShenandoahHeap::max_workers() { 1764 return _max_workers; 1765 } 1766 1767 void ShenandoahHeap::stop() { 1768 // The shutdown sequence should be able to terminate when GC is running. 1769 1770 // Step 0. Notify policy to disable event recording. 1771 _shenandoah_policy->record_shutdown(); 1772 1773 // Step 1. Notify control thread that we are in shutdown. 1774 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 1775 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 1776 control_thread()->prepare_for_graceful_shutdown(); 1777 1778 // Step 2. Notify GC workers that we are cancelling GC. 1779 cancel_gc(GCCause::_shenandoah_stop_vm); 1780 1781 // Step 3. Wait until GC worker exits normally. 1782 control_thread()->stop(); 1783 } 1784 1785 void ShenandoahHeap::stw_unload_classes(bool full_gc) { 1786 if (!unload_classes()) return; 1787 // Unload classes and purge SystemDictionary. 1788 { 1789 ShenandoahPhaseTimings::Phase phase = full_gc ? 1790 ShenandoahPhaseTimings::full_gc_purge_class_unload : 1791 ShenandoahPhaseTimings::degen_gc_purge_class_unload; 1792 ShenandoahGCPhase gc_phase(phase); 1793 ShenandoahGCWorkerPhase worker_phase(phase); 1794 bool purged_class = SystemDictionary::do_unloading(gc_timer()); 1795 1796 ShenandoahIsAliveSelector is_alive; 1797 uint num_workers = _workers->active_workers(); 1798 ShenandoahClassUnloadingTask unlink_task(phase, is_alive.is_alive_closure(), num_workers, purged_class); 1799 _workers->run_task(&unlink_task); 1800 } 1801 1802 { 1803 ShenandoahGCPhase phase(full_gc ? 1804 ShenandoahPhaseTimings::full_gc_purge_cldg : 1805 ShenandoahPhaseTimings::degen_gc_purge_cldg); 1806 ClassLoaderDataGraph::purge(/*at_safepoint*/true); 1807 } 1808 // Resize and verify metaspace 1809 MetaspaceGC::compute_new_size(); 1810 DEBUG_ONLY(MetaspaceUtils::verify();) 1811 } 1812 1813 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs), 1814 // so they should not have forwarded oops. 1815 // However, we do need to "null" dead oops in the roots, if can not be done 1816 // in concurrent cycles. 1817 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) { 1818 uint num_workers = _workers->active_workers(); 1819 ShenandoahPhaseTimings::Phase timing_phase = full_gc ? 1820 ShenandoahPhaseTimings::full_gc_purge_weak_par : 1821 ShenandoahPhaseTimings::degen_gc_purge_weak_par; 1822 ShenandoahGCPhase phase(timing_phase); 1823 ShenandoahGCWorkerPhase worker_phase(timing_phase); 1824 // Cleanup weak roots 1825 if (has_forwarded_objects()) { 1826 ShenandoahForwardedIsAliveClosure is_alive; 1827 ShenandoahUpdateRefsClosure keep_alive; 1828 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure> 1829 cleaning_task(timing_phase, &is_alive, &keep_alive, num_workers); 1830 _workers->run_task(&cleaning_task); 1831 } else { 1832 ShenandoahIsAliveClosure is_alive; 1833 #ifdef ASSERT 1834 ShenandoahAssertNotForwardedClosure verify_cl; 1835 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure> 1836 cleaning_task(timing_phase, &is_alive, &verify_cl, num_workers); 1837 #else 1838 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure> 1839 cleaning_task(timing_phase, &is_alive, &do_nothing_cl, num_workers); 1840 #endif 1841 _workers->run_task(&cleaning_task); 1842 } 1843 } 1844 1845 void ShenandoahHeap::parallel_cleaning(bool full_gc) { 1846 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1847 assert(is_stw_gc_in_progress(), "Only for Degenerated and Full GC"); 1848 ShenandoahGCPhase phase(full_gc ? 1849 ShenandoahPhaseTimings::full_gc_purge : 1850 ShenandoahPhaseTimings::degen_gc_purge); 1851 stw_weak_refs(full_gc); 1852 stw_process_weak_roots(full_gc); 1853 stw_unload_classes(full_gc); 1854 } 1855 1856 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 1857 set_gc_state_mask(HAS_FORWARDED, cond); 1858 } 1859 1860 void ShenandoahHeap::set_unload_classes(bool uc) { 1861 _unload_classes.set_cond(uc); 1862 } 1863 1864 bool ShenandoahHeap::unload_classes() const { 1865 return _unload_classes.is_set(); 1866 } 1867 1868 address ShenandoahHeap::in_cset_fast_test_addr() { 1869 ShenandoahHeap* heap = ShenandoahHeap::heap(); 1870 assert(heap->collection_set() != NULL, "Sanity"); 1871 return (address) heap->collection_set()->biased_map_address(); 1872 } 1873 1874 address ShenandoahHeap::cancelled_gc_addr() { 1875 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 1876 } 1877 1878 address ShenandoahHeap::gc_state_addr() { 1879 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 1880 } 1881 1882 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 1883 return Atomic::load(&_bytes_allocated_since_gc_start); 1884 } 1885 1886 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 1887 Atomic::store(&_bytes_allocated_since_gc_start, (size_t)0); 1888 } 1889 1890 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 1891 _degenerated_gc_in_progress.set_cond(in_progress); 1892 } 1893 1894 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 1895 _full_gc_in_progress.set_cond(in_progress); 1896 } 1897 1898 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 1899 assert (is_full_gc_in_progress(), "should be"); 1900 _full_gc_move_in_progress.set_cond(in_progress); 1901 } 1902 1903 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 1904 set_gc_state_mask(UPDATEREFS, in_progress); 1905 } 1906 1907 void ShenandoahHeap::register_nmethod(nmethod* nm) { 1908 ShenandoahCodeRoots::register_nmethod(nm); 1909 } 1910 1911 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 1912 ShenandoahCodeRoots::unregister_nmethod(nm); 1913 } 1914 1915 void ShenandoahHeap::flush_nmethod(nmethod* nm) { 1916 ShenandoahCodeRoots::flush_nmethod(nm); 1917 } 1918 1919 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 1920 heap_region_containing(o)->record_pin(); 1921 return o; 1922 } 1923 1924 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 1925 ShenandoahHeapRegion* r = heap_region_containing(o); 1926 assert(r != NULL, "Sanity"); 1927 assert(r->pin_count() > 0, "Region " SIZE_FORMAT " should have non-zero pins", r->index()); 1928 r->record_unpin(); 1929 } 1930 1931 void ShenandoahHeap::sync_pinned_region_status() { 1932 ShenandoahHeapLocker locker(lock()); 1933 1934 for (size_t i = 0; i < num_regions(); i++) { 1935 ShenandoahHeapRegion *r = get_region(i); 1936 if (r->is_active()) { 1937 if (r->is_pinned()) { 1938 if (r->pin_count() == 0) { 1939 r->make_unpinned(); 1940 } 1941 } else { 1942 if (r->pin_count() > 0) { 1943 r->make_pinned(); 1944 } 1945 } 1946 } 1947 } 1948 1949 assert_pinned_region_status(); 1950 } 1951 1952 #ifdef ASSERT 1953 void ShenandoahHeap::assert_pinned_region_status() { 1954 for (size_t i = 0; i < num_regions(); i++) { 1955 ShenandoahHeapRegion* r = get_region(i); 1956 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 1957 "Region " SIZE_FORMAT " pinning status is inconsistent", i); 1958 } 1959 } 1960 #endif 1961 1962 ConcurrentGCTimer* ShenandoahHeap::gc_timer() const { 1963 return _gc_timer; 1964 } 1965 1966 void ShenandoahHeap::prepare_concurrent_roots() { 1967 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1968 assert(!is_stw_gc_in_progress(), "Only concurrent GC"); 1969 set_concurrent_strong_root_in_progress(!collection_set()->is_empty()); 1970 set_concurrent_weak_root_in_progress(true); 1971 if (unload_classes()) { 1972 _unloader.prepare(); 1973 } 1974 } 1975 1976 void ShenandoahHeap::finish_concurrent_roots() { 1977 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 1978 assert(!is_stw_gc_in_progress(), "Only concurrent GC"); 1979 if (unload_classes()) { 1980 _unloader.finish(); 1981 } 1982 } 1983 1984 #ifdef ASSERT 1985 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 1986 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 1987 1988 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1989 if (UseDynamicNumberOfGCThreads) { 1990 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 1991 } else { 1992 // Use ParallelGCThreads inside safepoints 1993 assert(nworkers == ParallelGCThreads, "Use ParallelGCThreads within safepoints"); 1994 } 1995 } else { 1996 if (UseDynamicNumberOfGCThreads) { 1997 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 1998 } else { 1999 // Use ConcGCThreads outside safepoints 2000 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2001 } 2002 } 2003 } 2004 #endif 2005 2006 ShenandoahVerifier* ShenandoahHeap::verifier() { 2007 guarantee(ShenandoahVerify, "Should be enabled"); 2008 assert (_verifier != NULL, "sanity"); 2009 return _verifier; 2010 } 2011 2012 template<bool CONCURRENT> 2013 class ShenandoahUpdateHeapRefsTask : public WorkerTask { 2014 private: 2015 ShenandoahHeap* _heap; 2016 ShenandoahRegionIterator* _regions; 2017 public: 2018 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions) : 2019 WorkerTask("Shenandoah Update References"), 2020 _heap(ShenandoahHeap::heap()), 2021 _regions(regions) { 2022 } 2023 2024 void work(uint worker_id) { 2025 if (CONCURRENT) { 2026 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2027 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2028 do_work<ShenandoahConcUpdateRefsClosure>(); 2029 } else { 2030 ShenandoahParallelWorkerSession worker_session(worker_id); 2031 do_work<ShenandoahSTWUpdateRefsClosure>(); 2032 } 2033 } 2034 2035 private: 2036 template<class T> 2037 void do_work() { 2038 T cl; 2039 ShenandoahHeapRegion* r = _regions->next(); 2040 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2041 while (r != NULL) { 2042 HeapWord* update_watermark = r->get_update_watermark(); 2043 assert (update_watermark >= r->bottom(), "sanity"); 2044 if (r->is_active() && !r->is_cset()) { 2045 _heap->marked_object_oop_iterate(r, &cl, update_watermark); 2046 } 2047 if (ShenandoahPacing) { 2048 _heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom())); 2049 } 2050 if (_heap->check_cancelled_gc_and_yield(CONCURRENT)) { 2051 return; 2052 } 2053 r = _regions->next(); 2054 } 2055 } 2056 }; 2057 2058 void ShenandoahHeap::update_heap_references(bool concurrent) { 2059 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 2060 2061 if (concurrent) { 2062 ShenandoahUpdateHeapRefsTask<true> task(&_update_refs_iterator); 2063 workers()->run_task(&task); 2064 } else { 2065 ShenandoahUpdateHeapRefsTask<false> task(&_update_refs_iterator); 2066 workers()->run_task(&task); 2067 } 2068 } 2069 2070 2071 class ShenandoahFinalUpdateRefsUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 2072 private: 2073 ShenandoahHeapLock* const _lock; 2074 2075 public: 2076 ShenandoahFinalUpdateRefsUpdateRegionStateClosure() : _lock(ShenandoahHeap::heap()->lock()) {} 2077 2078 void heap_region_do(ShenandoahHeapRegion* r) { 2079 // Drop unnecessary "pinned" state from regions that does not have CP marks 2080 // anymore, as this would allow trashing them. 2081 2082 if (r->is_active()) { 2083 if (r->is_pinned()) { 2084 if (r->pin_count() == 0) { 2085 ShenandoahHeapLocker locker(_lock); 2086 r->make_unpinned(); 2087 } 2088 } else { 2089 if (r->pin_count() > 0) { 2090 ShenandoahHeapLocker locker(_lock); 2091 r->make_pinned(); 2092 } 2093 } 2094 } 2095 } 2096 2097 bool is_thread_safe() { return true; } 2098 }; 2099 2100 void ShenandoahHeap::update_heap_region_states(bool concurrent) { 2101 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2102 assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC"); 2103 2104 { 2105 ShenandoahGCPhase phase(concurrent ? 2106 ShenandoahPhaseTimings::final_update_refs_update_region_states : 2107 ShenandoahPhaseTimings::degen_gc_final_update_refs_update_region_states); 2108 ShenandoahFinalUpdateRefsUpdateRegionStateClosure cl; 2109 parallel_heap_region_iterate(&cl); 2110 2111 assert_pinned_region_status(); 2112 } 2113 2114 { 2115 ShenandoahGCPhase phase(concurrent ? 2116 ShenandoahPhaseTimings::final_update_refs_trash_cset : 2117 ShenandoahPhaseTimings::degen_gc_final_update_refs_trash_cset); 2118 trash_cset_regions(); 2119 } 2120 } 2121 2122 void ShenandoahHeap::rebuild_free_set(bool concurrent) { 2123 { 2124 ShenandoahGCPhase phase(concurrent ? 2125 ShenandoahPhaseTimings::final_update_refs_rebuild_freeset : 2126 ShenandoahPhaseTimings::degen_gc_final_update_refs_rebuild_freeset); 2127 ShenandoahHeapLocker locker(lock()); 2128 _free_set->rebuild(); 2129 } 2130 } 2131 2132 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2133 print_on(st); 2134 print_heap_regions_on(st); 2135 } 2136 2137 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2138 size_t slice = r->index() / _bitmap_regions_per_slice; 2139 2140 size_t regions_from = _bitmap_regions_per_slice * slice; 2141 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2142 for (size_t g = regions_from; g < regions_to; g++) { 2143 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2144 if (skip_self && g == r->index()) continue; 2145 if (get_region(g)->is_committed()) { 2146 return true; 2147 } 2148 } 2149 return false; 2150 } 2151 2152 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2153 shenandoah_assert_heaplocked(); 2154 2155 // Bitmaps in special regions do not need commits 2156 if (_bitmap_region_special) { 2157 return true; 2158 } 2159 2160 if (is_bitmap_slice_committed(r, true)) { 2161 // Some other region from the group is already committed, meaning the bitmap 2162 // slice is already committed, we exit right away. 2163 return true; 2164 } 2165 2166 // Commit the bitmap slice: 2167 size_t slice = r->index() / _bitmap_regions_per_slice; 2168 size_t off = _bitmap_bytes_per_slice * slice; 2169 size_t len = _bitmap_bytes_per_slice; 2170 char* start = (char*) _bitmap_region.start() + off; 2171 2172 if (!os::commit_memory(start, len, false)) { 2173 return false; 2174 } 2175 2176 if (AlwaysPreTouch) { 2177 os::pretouch_memory(start, start + len, _pretouch_bitmap_page_size); 2178 } 2179 2180 return true; 2181 } 2182 2183 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2184 shenandoah_assert_heaplocked(); 2185 2186 // Bitmaps in special regions do not need uncommits 2187 if (_bitmap_region_special) { 2188 return true; 2189 } 2190 2191 if (is_bitmap_slice_committed(r, true)) { 2192 // Some other region from the group is still committed, meaning the bitmap 2193 // slice is should stay committed, exit right away. 2194 return true; 2195 } 2196 2197 // Uncommit the bitmap slice: 2198 size_t slice = r->index() / _bitmap_regions_per_slice; 2199 size_t off = _bitmap_bytes_per_slice * slice; 2200 size_t len = _bitmap_bytes_per_slice; 2201 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2202 return false; 2203 } 2204 return true; 2205 } 2206 2207 void ShenandoahHeap::safepoint_synchronize_begin() { 2208 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2209 SuspendibleThreadSet::synchronize(); 2210 } 2211 } 2212 2213 void ShenandoahHeap::safepoint_synchronize_end() { 2214 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2215 SuspendibleThreadSet::desynchronize(); 2216 } 2217 } 2218 2219 void ShenandoahHeap::entry_uncommit(double shrink_before, size_t shrink_until) { 2220 static const char *msg = "Concurrent uncommit"; 2221 ShenandoahConcurrentPhase gc_phase(msg, ShenandoahPhaseTimings::conc_uncommit, true /* log_heap_usage */); 2222 EventMark em("%s", msg); 2223 2224 op_uncommit(shrink_before, shrink_until); 2225 } 2226 2227 void ShenandoahHeap::try_inject_alloc_failure() { 2228 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2229 _inject_alloc_failure.set(); 2230 os::naked_short_sleep(1); 2231 if (cancelled_gc()) { 2232 log_info(gc)("Allocation failure was successfully injected"); 2233 } 2234 } 2235 } 2236 2237 bool ShenandoahHeap::should_inject_alloc_failure() { 2238 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2239 } 2240 2241 void ShenandoahHeap::initialize_serviceability() { 2242 _memory_pool = new ShenandoahMemoryPool(this); 2243 _cycle_memory_manager.add_pool(_memory_pool); 2244 _stw_memory_manager.add_pool(_memory_pool); 2245 } 2246 2247 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 2248 GrowableArray<GCMemoryManager*> memory_managers(2); 2249 memory_managers.append(&_cycle_memory_manager); 2250 memory_managers.append(&_stw_memory_manager); 2251 return memory_managers; 2252 } 2253 2254 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 2255 GrowableArray<MemoryPool*> memory_pools(1); 2256 memory_pools.append(_memory_pool); 2257 return memory_pools; 2258 } 2259 2260 MemoryUsage ShenandoahHeap::memory_usage() { 2261 return _memory_pool->get_memory_usage(); 2262 } 2263 2264 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2265 _heap(ShenandoahHeap::heap()), 2266 _index(0) {} 2267 2268 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2269 _heap(heap), 2270 _index(0) {} 2271 2272 void ShenandoahRegionIterator::reset() { 2273 _index = 0; 2274 } 2275 2276 bool ShenandoahRegionIterator::has_next() const { 2277 return _index < _heap->num_regions(); 2278 } 2279 2280 char ShenandoahHeap::gc_state() const { 2281 return _gc_state.raw_value(); 2282 } 2283 2284 ShenandoahLiveData* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2285 #ifdef ASSERT 2286 assert(_liveness_cache != NULL, "sanity"); 2287 assert(worker_id < _max_workers, "sanity"); 2288 for (uint i = 0; i < num_regions(); i++) { 2289 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 2290 } 2291 #endif 2292 return _liveness_cache[worker_id]; 2293 } 2294 2295 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 2296 assert(worker_id < _max_workers, "sanity"); 2297 assert(_liveness_cache != NULL, "sanity"); 2298 ShenandoahLiveData* ld = _liveness_cache[worker_id]; 2299 for (uint i = 0; i < num_regions(); i++) { 2300 ShenandoahLiveData live = ld[i]; 2301 if (live > 0) { 2302 ShenandoahHeapRegion* r = get_region(i); 2303 r->increase_live_data_gc_words(live); 2304 ld[i] = 0; 2305 } 2306 } 2307 }