1 /* 2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "memory/allocation.hpp" 26 27 #include "gc_implementation/shared/gcTimer.hpp" 28 #include "gc_implementation/shenandoah/shenandoahGCTraceTime.hpp" 29 #include "gc_implementation/shared/parallelCleaning.hpp" 30 31 #include "gc_implementation/shenandoah/shenandoahAllocTracker.hpp" 32 #include "gc_implementation/shenandoah/shenandoahBarrierSet.hpp" 33 #include "gc_implementation/shenandoah/shenandoahClosures.inline.hpp" 34 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 35 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp" 36 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.inline.hpp" 37 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp" 38 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp" 39 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp" 40 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp" 41 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 42 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp" 43 #include "gc_implementation/shenandoah/shenandoahMarkCompact.hpp" 44 #include "gc_implementation/shenandoah/shenandoahMarkingContext.inline.hpp" 45 #include "gc_implementation/shenandoah/shenandoahMonitoringSupport.hpp" 46 #include "gc_implementation/shenandoah/shenandoahMetrics.hpp" 47 #include "gc_implementation/shenandoah/shenandoahOopClosures.inline.hpp" 48 #include "gc_implementation/shenandoah/shenandoahPacer.inline.hpp" 49 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp" 50 #include "gc_implementation/shenandoah/shenandoahTaskqueue.hpp" 51 #include "gc_implementation/shenandoah/shenandoahUtils.hpp" 52 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp" 53 #include "gc_implementation/shenandoah/shenandoahCodeRoots.hpp" 54 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp" 55 #include "gc_implementation/shenandoah/shenandoahWorkGroup.hpp" 56 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp" 57 #include "gc_implementation/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp" 58 #include "gc_implementation/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp" 59 #include "gc_implementation/shenandoah/heuristics/shenandoahCompactHeuristics.hpp" 60 #include "gc_implementation/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp" 61 #include "gc_implementation/shenandoah/heuristics/shenandoahStaticHeuristics.hpp" 62 63 #include "memory/metaspace.hpp" 64 #include "runtime/vmThread.hpp" 65 #include "services/mallocTracker.hpp" 66 67 #ifdef ASSERT 68 template <class T> 69 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) { 70 T o = oopDesc::load_heap_oop(p); 71 if (! oopDesc::is_null(o)) { 72 oop obj = oopDesc::decode_heap_oop_not_null(o); 73 shenandoah_assert_not_forwarded(p, obj); 74 } 75 } 76 77 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 78 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); } 79 #endif 80 81 class ShenandoahPretouchHeapTask : public AbstractGangTask { 82 private: 83 ShenandoahRegionIterator _regions; 84 const size_t _page_size; 85 public: 86 ShenandoahPretouchHeapTask(size_t page_size) : 87 AbstractGangTask("Shenandoah Pretouch Heap"), 88 _page_size(page_size) {} 89 90 virtual void work(uint worker_id) { 91 ShenandoahHeapRegion* r = _regions.next(); 92 while (r != NULL) { 93 os::pretouch_memory((char*) r->bottom(), (char*) r->end()); 94 r = _regions.next(); 95 } 96 } 97 }; 98 99 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 100 private: 101 ShenandoahRegionIterator _regions; 102 char* _bitmap_base; 103 const size_t _bitmap_size; 104 const size_t _page_size; 105 public: 106 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 107 AbstractGangTask("Shenandoah Pretouch Bitmap"), 108 _bitmap_base(bitmap_base), 109 _bitmap_size(bitmap_size), 110 _page_size(page_size) {} 111 112 virtual void work(uint worker_id) { 113 ShenandoahHeapRegion* r = _regions.next(); 114 while (r != NULL) { 115 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 116 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 117 assert (end <= _bitmap_size, err_msg("end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size)); 118 119 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end); 120 121 r = _regions.next(); 122 } 123 } 124 }; 125 126 jint ShenandoahHeap::initialize() { 127 CollectedHeap::pre_initialize(); 128 129 initialize_heuristics(); 130 131 // 132 // Figure out heap sizing 133 // 134 135 size_t init_byte_size = collector_policy()->initial_heap_byte_size(); 136 size_t min_byte_size = collector_policy()->min_heap_byte_size(); 137 size_t max_byte_size = collector_policy()->max_heap_byte_size(); 138 size_t heap_alignment = collector_policy()->heap_alignment(); 139 140 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 141 142 if (ShenandoahAlwaysPreTouch) { 143 // Enabled pre-touch means the entire heap is committed right away. 144 init_byte_size = max_byte_size; 145 } 146 147 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 148 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 149 150 _num_regions = ShenandoahHeapRegion::region_count(); 151 152 size_t num_committed_regions = init_byte_size / reg_size_bytes; 153 num_committed_regions = MIN2(num_committed_regions, _num_regions); 154 assert(num_committed_regions <= _num_regions, "sanity"); 155 _initial_size = num_committed_regions * reg_size_bytes; 156 157 size_t num_min_regions = min_byte_size / reg_size_bytes; 158 num_min_regions = MIN2(num_min_regions, _num_regions); 159 assert(num_min_regions <= _num_regions, "sanity"); 160 _minimum_size = num_min_regions * reg_size_bytes; 161 162 _committed = _initial_size; 163 164 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 165 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 166 167 // 168 // Reserve and commit memory for heap 169 // 170 171 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 172 _reserved.set_word_size(0); 173 _reserved.set_start((HeapWord*)heap_rs.base()); 174 _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size())); 175 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 176 _heap_region_special = heap_rs.special(); 177 178 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 179 err_msg("Misaligned heap: " PTR_FORMAT, p2i(base()))); 180 181 #if SHENANDOAH_OPTIMIZED_OBJTASK 182 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 183 // Fail if we ever attempt to address more than we can. 184 if ((uintptr_t)(heap_rs.base() + heap_rs.size()) >= ObjArrayChunkedTask::max_addressable()) { 185 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 186 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 187 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 188 p2i(heap_rs.base()), p2i(heap_rs.base() + heap_rs.size()), ObjArrayChunkedTask::max_addressable()); 189 vm_exit_during_initialization("Fatal Error", buf); 190 } 191 #endif 192 193 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 194 if (!_heap_region_special) { 195 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 196 "Cannot commit heap memory"); 197 } 198 199 // 200 // Reserve and commit memory for bitmap(s) 201 // 202 203 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 204 _bitmap_size = align_size_up(_bitmap_size, bitmap_page_size); 205 206 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 207 208 guarantee(bitmap_bytes_per_region != 0, 209 err_msg("Bitmap bytes per region should not be zero")); 210 guarantee(is_power_of_2(bitmap_bytes_per_region), 211 err_msg("Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region)); 212 213 if (bitmap_page_size > bitmap_bytes_per_region) { 214 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 215 _bitmap_bytes_per_slice = bitmap_page_size; 216 } else { 217 _bitmap_regions_per_slice = 1; 218 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 219 } 220 221 guarantee(_bitmap_regions_per_slice >= 1, 222 err_msg("Should have at least one region per slice: " SIZE_FORMAT, 223 _bitmap_regions_per_slice)); 224 225 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 226 err_msg("Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 227 _bitmap_bytes_per_slice, bitmap_page_size)); 228 229 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 230 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 231 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 232 _bitmap_region_special = bitmap.special(); 233 234 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 235 align_size_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 236 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 237 if (!_bitmap_region_special) { 238 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 239 "Cannot commit bitmap memory"); 240 } 241 242 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 243 244 if (ShenandoahVerify) { 245 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 246 if (!verify_bitmap.special()) { 247 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 248 "Cannot commit verification bitmap memory"); 249 } 250 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 251 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 252 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 253 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 254 } 255 256 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 257 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 258 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 259 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 260 _aux_bitmap_region_special = aux_bitmap.special(); 261 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 262 263 // 264 // Create regions and region sets 265 // 266 267 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 268 _free_set = new ShenandoahFreeSet(this, _num_regions); 269 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 270 271 { 272 ShenandoahHeapLocker locker(lock()); 273 274 size_t size_words = ShenandoahHeapRegion::region_size_words(); 275 276 for (size_t i = 0; i < _num_regions; i++) { 277 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; 278 bool is_committed = i < num_committed_regions; 279 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); 280 281 _marking_context->initialize_top_at_mark_start(r); 282 _regions[i] = r; 283 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 284 } 285 286 // Initialize to complete 287 _marking_context->mark_complete(); 288 289 _free_set->rebuild(); 290 } 291 292 if (ShenandoahAlwaysPreTouch) { 293 assert(!AlwaysPreTouch, "Should have been overridden"); 294 295 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 296 // before initialize() below zeroes it with initializing thread. For any given region, 297 // we touch the region and the corresponding bitmaps from the same thread. 298 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 299 300 size_t pretouch_heap_page_size = heap_page_size; 301 size_t pretouch_bitmap_page_size = bitmap_page_size; 302 303 #ifdef LINUX 304 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 305 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 306 // them into huge one. Therefore, we need to pretouch with smaller pages. 307 if (UseTransparentHugePages) { 308 pretouch_heap_page_size = (size_t)os::vm_page_size(); 309 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 310 } 311 #endif 312 313 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 314 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 315 316 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 317 _num_regions, pretouch_bitmap_page_size); 318 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 319 _workers->run_task(&bcl); 320 321 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 322 _num_regions, pretouch_heap_page_size); 323 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 324 _workers->run_task(&hcl); 325 } 326 327 // 328 // Initialize the rest of GC subsystems 329 // 330 331 set_barrier_set(new ShenandoahBarrierSet(this)); 332 333 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 334 for (uint worker = 0; worker < _max_workers; worker++) { 335 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 336 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 337 } 338 339 // The call below uses stuff (the SATB* things) that are in G1, but probably 340 // belong into a shared location. 341 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon, 342 SATB_Q_FL_lock, 343 20 /*G1SATBProcessCompletedThreshold */, 344 Shared_SATB_Q_lock); 345 346 _monitoring_support = new ShenandoahMonitoringSupport(this); 347 _phase_timings = new ShenandoahPhaseTimings(); 348 ShenandoahStringDedup::initialize(); 349 ShenandoahCodeRoots::initialize(); 350 351 if (ShenandoahAllocationTrace) { 352 _alloc_tracker = new ShenandoahAllocTracker(); 353 } 354 355 if (ShenandoahPacing) { 356 _pacer = new ShenandoahPacer(this); 357 _pacer->setup_for_idle(); 358 } else { 359 _pacer = NULL; 360 } 361 362 _control_thread = new ShenandoahControlThread(); 363 364 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 365 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 366 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 367 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 368 ); 369 370 return JNI_OK; 371 } 372 373 #ifdef _MSC_VER 374 #pragma warning( push ) 375 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 376 #endif 377 378 void ShenandoahHeap::initialize_heuristics() { 379 if (ShenandoahGCHeuristics != NULL) { 380 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) { 381 _heuristics = new ShenandoahAggressiveHeuristics(); 382 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) { 383 _heuristics = new ShenandoahStaticHeuristics(); 384 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) { 385 _heuristics = new ShenandoahAdaptiveHeuristics(); 386 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) { 387 _heuristics = new ShenandoahPassiveHeuristics(); 388 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) { 389 _heuristics = new ShenandoahCompactHeuristics(); 390 } else { 391 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option"); 392 } 393 394 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 395 vm_exit_during_initialization( 396 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 397 _heuristics->name())); 398 } 399 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 400 vm_exit_during_initialization( 401 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 402 _heuristics->name())); 403 } 404 log_info(gc, init)("Shenandoah heuristics: %s", 405 _heuristics->name()); 406 } else { 407 ShouldNotReachHere(); 408 } 409 } 410 411 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 412 SharedHeap(policy), 413 _shenandoah_policy(policy), 414 _heap_region_special(false), 415 _regions(NULL), 416 _free_set(NULL), 417 _collection_set(NULL), 418 _update_refs_iterator(this), 419 _bytes_allocated_since_gc_start(0), 420 _max_workers((uint)MAX2(ConcGCThreads, ParallelGCThreads)), 421 _ref_processor(NULL), 422 _marking_context(NULL), 423 _bitmap_size(0), 424 _bitmap_regions_per_slice(0), 425 _bitmap_bytes_per_slice(0), 426 _bitmap_region_special(false), 427 _aux_bitmap_region_special(false), 428 _liveness_cache(NULL), 429 _aux_bit_map(), 430 _verifier(NULL), 431 _pacer(NULL), 432 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 433 _phase_timings(NULL), 434 _alloc_tracker(NULL) 435 { 436 log_info(gc, init)("GC threads: " UINTX_FORMAT " parallel, " UINTX_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); 437 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); 438 439 _scm = new ShenandoahConcurrentMark(); 440 _full_gc = new ShenandoahMarkCompact(); 441 _used = 0; 442 443 _max_workers = MAX2(_max_workers, 1U); 444 445 // SharedHeap did not initialize this for us, and we want our own workgang anyway. 446 assert(SharedHeap::_workers == NULL && _workers == NULL, "Should not be initialized yet"); 447 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, 448 /* are_GC_task_threads */true, 449 /* are_ConcurrentGC_threads */false); 450 if (_workers == NULL) { 451 vm_exit_during_initialization("Failed necessary allocation."); 452 } else { 453 _workers->initialize_workers(); 454 } 455 assert(SharedHeap::_workers == _workers, "Sanity: initialized the correct field"); 456 } 457 458 #ifdef _MSC_VER 459 #pragma warning( pop ) 460 #endif 461 462 class ShenandoahResetBitmapTask : public AbstractGangTask { 463 private: 464 ShenandoahRegionIterator _regions; 465 466 public: 467 ShenandoahResetBitmapTask() : 468 AbstractGangTask("Parallel Reset Bitmap Task") {} 469 470 void work(uint worker_id) { 471 ShenandoahHeapRegion* region = _regions.next(); 472 ShenandoahHeap* heap = ShenandoahHeap::heap(); 473 ShenandoahMarkingContext* const ctx = heap->marking_context(); 474 while (region != NULL) { 475 if (heap->is_bitmap_slice_committed(region)) { 476 ctx->clear_bitmap(region); 477 } 478 region = _regions.next(); 479 } 480 } 481 }; 482 483 void ShenandoahHeap::reset_mark_bitmap() { 484 assert_gc_workers(_workers->active_workers()); 485 mark_incomplete_marking_context(); 486 487 ShenandoahResetBitmapTask task; 488 _workers->run_task(&task); 489 } 490 491 void ShenandoahHeap::print_on(outputStream* st) const { 492 st->print_cr("Shenandoah Heap"); 493 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used", 494 max_capacity() / K, committed() / K, used() / K); 495 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions", 496 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K); 497 498 st->print("Status: "); 499 if (has_forwarded_objects()) st->print("has forwarded objects, "); 500 if (is_concurrent_mark_in_progress()) st->print("marking, "); 501 if (is_evacuation_in_progress()) st->print("evacuating, "); 502 if (is_update_refs_in_progress()) st->print("updating refs, "); 503 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 504 if (is_full_gc_in_progress()) st->print("full gc, "); 505 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 506 507 if (cancelled_gc()) { 508 st->print("cancelled"); 509 } else { 510 st->print("not cancelled"); 511 } 512 st->cr(); 513 514 st->print_cr("Reserved region:"); 515 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 516 p2i(reserved_region().start()), 517 p2i(reserved_region().end())); 518 519 ShenandoahCollectionSet* cset = collection_set(); 520 st->print_cr("Collection set:"); 521 if (cset != NULL) { 522 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 523 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 524 } else { 525 st->print_cr(" (NULL)"); 526 } 527 528 st->cr(); 529 MetaspaceAux::print_on(st); 530 531 if (Verbose) { 532 print_heap_regions_on(st); 533 } 534 } 535 536 class ShenandoahInitGCLABClosure : public ThreadClosure { 537 public: 538 void do_thread(Thread* thread) { 539 assert(thread == NULL || !thread->is_Java_thread(), "Don't expect JavaThread this early"); 540 if (thread != NULL && thread->is_Worker_thread()) { 541 thread->gclab().initialize(true); 542 } 543 } 544 }; 545 546 void ShenandoahHeap::post_initialize() { 547 if (UseTLAB) { 548 MutexLocker ml(Threads_lock); 549 550 ShenandoahInitGCLABClosure init_gclabs; 551 Threads::threads_do(&init_gclabs); 552 } 553 554 _scm->initialize(_max_workers); 555 _full_gc->initialize(_gc_timer); 556 557 ref_processing_init(); 558 559 _heuristics->initialize(); 560 } 561 562 size_t ShenandoahHeap::used() const { 563 OrderAccess::acquire(); 564 return (size_t) _used; 565 } 566 567 size_t ShenandoahHeap::committed() const { 568 OrderAccess::acquire(); 569 return _committed; 570 } 571 572 void ShenandoahHeap::increase_committed(size_t bytes) { 573 assert_heaplock_or_safepoint(); 574 _committed += bytes; 575 } 576 577 void ShenandoahHeap::decrease_committed(size_t bytes) { 578 assert_heaplock_or_safepoint(); 579 _committed -= bytes; 580 } 581 582 void ShenandoahHeap::increase_used(size_t bytes) { 583 Atomic::add(bytes, &_used); 584 } 585 586 void ShenandoahHeap::set_used(size_t bytes) { 587 OrderAccess::release_store_fence(&_used, bytes); 588 } 589 590 void ShenandoahHeap::decrease_used(size_t bytes) { 591 assert(used() >= bytes, "never decrease heap size by more than we've left"); 592 Atomic::add(-(jlong)bytes, &_used); 593 } 594 595 void ShenandoahHeap::increase_allocated(size_t bytes) { 596 Atomic::add(bytes, &_bytes_allocated_since_gc_start); 597 } 598 599 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 600 size_t bytes = words * HeapWordSize; 601 if (!waste) { 602 increase_used(bytes); 603 } 604 increase_allocated(bytes); 605 if (ShenandoahPacing) { 606 control_thread()->pacing_notify_alloc(words); 607 if (waste) { 608 pacer()->claim_for_alloc(words, true); 609 } 610 } 611 } 612 613 size_t ShenandoahHeap::capacity() const { 614 return committed(); 615 } 616 617 size_t ShenandoahHeap::max_capacity() const { 618 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 619 } 620 621 size_t ShenandoahHeap::min_capacity() const { 622 return _minimum_size; 623 } 624 625 size_t ShenandoahHeap::initial_capacity() const { 626 return _initial_size; 627 } 628 629 bool ShenandoahHeap::is_in(const void* p) const { 630 HeapWord* heap_base = (HeapWord*) base(); 631 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 632 return p >= heap_base && p < last_region_end; 633 } 634 635 void ShenandoahHeap::op_uncommit(double shrink_before) { 636 assert (ShenandoahUncommit, "should be enabled"); 637 638 // Application allocates from the beginning of the heap, and GC allocates at 639 // the end of it. It is more efficient to uncommit from the end, so that applications 640 // could enjoy the near committed regions. GC allocations are much less frequent, 641 // and therefore can accept the committing costs. 642 643 size_t count = 0; 644 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 645 ShenandoahHeapRegion* r = get_region(i - 1); 646 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 647 ShenandoahHeapLocker locker(lock()); 648 if (r->is_empty_committed()) { 649 // Do not uncommit below minimal capacity 650 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 651 break; 652 } 653 654 r->make_uncommitted(); 655 count++; 656 } 657 } 658 SpinPause(); // allow allocators to take the lock 659 } 660 661 if (count > 0) { 662 _control_thread->notify_heap_changed(); 663 } 664 } 665 666 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 667 // Retain tlab and allocate object in shared space if 668 // the amount free in the tlab is too large to discard. 669 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) { 670 thread->gclab().record_slow_allocation(size); 671 return NULL; 672 } 673 674 // Discard gclab and allocate a new one. 675 // To minimize fragmentation, the last GCLAB may be smaller than the rest. 676 size_t new_gclab_size = thread->gclab().compute_size(size); 677 678 thread->gclab().clear_before_allocation(); 679 680 if (new_gclab_size == 0) { 681 return NULL; 682 } 683 684 // Allocated object should fit in new GCLAB, and new_gclab_size should be larger than min 685 size_t min_size = MAX2(size + ThreadLocalAllocBuffer::alignment_reserve(), ThreadLocalAllocBuffer::min_size()); 686 new_gclab_size = MAX2(new_gclab_size, min_size); 687 688 // Allocate a new GCLAB... 689 size_t actual_size = 0; 690 HeapWord* obj = allocate_new_gclab(min_size, new_gclab_size, &actual_size); 691 692 if (obj == NULL) { 693 return NULL; 694 } 695 696 assert (size <= actual_size, "allocation should fit"); 697 698 if (ZeroTLAB) { 699 // ..and clear it. 700 Copy::zero_to_words(obj, actual_size); 701 } else { 702 // ...and zap just allocated object. 703 #ifdef ASSERT 704 // Skip mangling the space corresponding to the object header to 705 // ensure that the returned space is not considered parsable by 706 // any concurrent GC thread. 707 size_t hdr_size = oopDesc::header_size(); 708 Copy::fill_to_words(obj + hdr_size, actual_size - hdr_size, badHeapWordVal); 709 #endif // ASSERT 710 } 711 thread->gclab().fill(obj, obj + size, actual_size); 712 return obj; 713 } 714 715 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) { 716 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(word_size); 717 return allocate_memory(req); 718 } 719 720 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 721 size_t word_size, 722 size_t* actual_size) { 723 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 724 HeapWord* res = allocate_memory(req); 725 if (res != NULL) { 726 *actual_size = req.actual_size(); 727 } else { 728 *actual_size = 0; 729 } 730 return res; 731 } 732 733 ShenandoahHeap* ShenandoahHeap::heap() { 734 CollectedHeap* heap = Universe::heap(); 735 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); 736 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap"); 737 return (ShenandoahHeap*) heap; 738 } 739 740 ShenandoahHeap* ShenandoahHeap::heap_no_check() { 741 CollectedHeap* heap = Universe::heap(); 742 return (ShenandoahHeap*) heap; 743 } 744 745 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 746 ShenandoahAllocTrace trace_alloc(req.size(), req.type()); 747 748 intptr_t pacer_epoch = 0; 749 bool in_new_region = false; 750 HeapWord* result = NULL; 751 752 if (req.is_mutator_alloc()) { 753 if (ShenandoahPacing) { 754 pacer()->pace_for_alloc(req.size()); 755 pacer_epoch = pacer()->epoch(); 756 } 757 758 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 759 result = allocate_memory_under_lock(req, in_new_region); 760 } 761 762 // Allocation failed, block until control thread reacted, then retry allocation. 763 // 764 // It might happen that one of the threads requesting allocation would unblock 765 // way later after GC happened, only to fail the second allocation, because 766 // other threads have already depleted the free storage. In this case, a better 767 // strategy is to try again, as long as GC makes progress. 768 // 769 // Then, we need to make sure the allocation was retried after at least one 770 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 771 772 size_t tries = 0; 773 774 while (result == NULL && _progress_last_gc.is_set()) { 775 tries++; 776 control_thread()->handle_alloc_failure(req.size()); 777 result = allocate_memory_under_lock(req, in_new_region); 778 } 779 780 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 781 tries++; 782 control_thread()->handle_alloc_failure(req.size()); 783 result = allocate_memory_under_lock(req, in_new_region); 784 } 785 786 } else { 787 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 788 result = allocate_memory_under_lock(req, in_new_region); 789 // Do not call handle_alloc_failure() here, because we cannot block. 790 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac(). 791 } 792 793 if (in_new_region) { 794 control_thread()->notify_heap_changed(); 795 } 796 797 if (result != NULL) { 798 size_t requested = req.size(); 799 size_t actual = req.actual_size(); 800 801 assert (req.is_lab_alloc() || (requested == actual), 802 err_msg("Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 803 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual)); 804 805 if (req.is_mutator_alloc()) { 806 notify_mutator_alloc_words(actual, false); 807 808 // If we requested more than we were granted, give the rest back to pacer. 809 // This only matters if we are in the same pacing epoch: do not try to unpace 810 // over the budget for the other phase. 811 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 812 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 813 } 814 } else { 815 increase_used(actual*HeapWordSize); 816 } 817 } 818 819 return result; 820 } 821 822 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 823 ShenandoahHeapLocker locker(lock()); 824 return _free_set->allocate(req, in_new_region); 825 } 826 827 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 828 bool* gc_overhead_limit_was_exceeded) { 829 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 830 HeapWord* result = allocate_memory(req); 831 if (result != NULL) { 832 assert(! in_collection_set(result), "never allocate in targetted region"); 833 return result; 834 } else { 835 return NULL; 836 } 837 } 838 839 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 840 private: 841 ShenandoahHeap* const _heap; 842 Thread* const _thread; 843 public: 844 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 845 _heap(heap), _thread(Thread::current()) {} 846 847 void do_object(oop p) { 848 shenandoah_assert_marked(NULL, p); 849 if (!p->is_forwarded()) { 850 _heap->evacuate_object(p, _thread); 851 } 852 } 853 }; 854 855 class ShenandoahEvacuationTask : public AbstractGangTask { 856 private: 857 ShenandoahHeap* const _sh; 858 ShenandoahCollectionSet* const _cs; 859 bool _concurrent; 860 public: 861 ShenandoahEvacuationTask(ShenandoahHeap* sh, 862 ShenandoahCollectionSet* cs, 863 bool concurrent) : 864 AbstractGangTask("Parallel Evacuation Task"), 865 _sh(sh), 866 _cs(cs), 867 _concurrent(concurrent) 868 {} 869 870 void work(uint worker_id) { 871 ShenandoahEvacOOMScope oom_evac_scope; 872 if (_concurrent) { 873 ShenandoahConcurrentWorkerSession worker_session(worker_id); 874 do_work(); 875 } else { 876 ShenandoahParallelWorkerSession worker_session(worker_id); 877 do_work(); 878 } 879 } 880 881 private: 882 void do_work() { 883 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 884 ShenandoahHeapRegion* r; 885 while ((r =_cs->claim_next()) != NULL) { 886 assert(r->has_live(), "all-garbage regions are reclaimed early"); 887 _sh->marked_object_iterate(r, &cl); 888 889 if (ShenandoahPacing) { 890 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 891 } 892 893 if (_sh->cancelled_gc()) { 894 break; 895 } 896 } 897 } 898 }; 899 900 void ShenandoahHeap::trash_cset_regions() { 901 ShenandoahHeapLocker locker(lock()); 902 903 ShenandoahCollectionSet* set = collection_set(); 904 ShenandoahHeapRegion* r; 905 set->clear_current_index(); 906 while ((r = set->next()) != NULL) { 907 r->make_trash(); 908 } 909 collection_set()->clear(); 910 } 911 912 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 913 st->print_cr("Heap Regions:"); 914 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 915 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 916 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); 917 918 for (size_t i = 0; i < num_regions(); i++) { 919 get_region(i)->print_on(st); 920 } 921 } 922 923 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 924 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 925 926 oop humongous_obj = oop(start->bottom()); 927 size_t size = humongous_obj->size(); 928 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 929 size_t index = start->region_number() + required_regions - 1; 930 931 assert(!start->has_live(), "liveness must be zero"); 932 933 for(size_t i = 0; i < required_regions; i++) { 934 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 935 // as it expects that every region belongs to a humongous region starting with a humongous start region. 936 ShenandoahHeapRegion* region = get_region(index --); 937 938 assert(region->is_humongous(), "expect correct humongous start or continuation"); 939 assert(!region->is_cset(), "Humongous region should not be in collection set"); 940 941 region->make_trash_immediate(); 942 } 943 } 944 945 class ShenandoahRetireGCLABClosure : public ThreadClosure { 946 private: 947 bool _retire; 948 public: 949 ShenandoahRetireGCLABClosure(bool retire) : _retire(retire) {}; 950 951 void do_thread(Thread* thread) { 952 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 953 thread->gclab().make_parsable(_retire); 954 } 955 }; 956 957 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 958 if (UseTLAB) { 959 CollectedHeap::ensure_parsability(retire_tlabs); 960 ShenandoahRetireGCLABClosure cl(retire_tlabs); 961 Threads::java_threads_do(&cl); 962 _workers->threads_do(&cl); 963 } 964 } 965 966 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 967 private: 968 ShenandoahRootEvacuator* _rp; 969 970 public: 971 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 972 AbstractGangTask("Shenandoah evacuate and update roots"), 973 _rp(rp) {} 974 975 void work(uint worker_id) { 976 ShenandoahParallelWorkerSession worker_session(worker_id); 977 ShenandoahEvacOOMScope oom_evac_scope; 978 ShenandoahEvacuateUpdateRootsClosure cl; 979 980 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 981 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id); 982 } 983 }; 984 985 void ShenandoahHeap::evacuate_and_update_roots() { 986 COMPILER2_PRESENT(DerivedPointerTable::clear()); 987 988 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 989 990 { 991 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac); 992 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 993 workers()->run_task(&roots_task); 994 } 995 996 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 997 } 998 999 void ShenandoahHeap::roots_iterate(OopClosure* cl) { 1000 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1001 1002 CodeBlobToOopClosure blobsCl(cl, false); 1003 CLDToOopClosure cldCl(cl); 1004 1005 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases); 1006 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0); 1007 } 1008 1009 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1010 // Returns size in bytes 1011 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1012 } 1013 1014 size_t ShenandoahHeap::max_tlab_size() const { 1015 // Returns size in words 1016 return ShenandoahHeapRegion::max_tlab_size_words(); 1017 } 1018 1019 class ShenandoahResizeGCLABClosure : public ThreadClosure { 1020 public: 1021 void do_thread(Thread* thread) { 1022 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 1023 thread->gclab().resize(); 1024 } 1025 }; 1026 1027 void ShenandoahHeap::resize_all_tlabs() { 1028 CollectedHeap::resize_all_tlabs(); 1029 1030 ShenandoahResizeGCLABClosure cl; 1031 Threads::java_threads_do(&cl); 1032 _workers->threads_do(&cl); 1033 } 1034 1035 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure { 1036 public: 1037 void do_thread(Thread* thread) { 1038 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 1039 thread->gclab().accumulate_statistics(); 1040 thread->gclab().initialize_statistics(); 1041 } 1042 }; 1043 1044 void ShenandoahHeap::accumulate_statistics_all_gclabs() { 1045 ShenandoahAccumulateStatisticsGCLABClosure cl; 1046 Threads::java_threads_do(&cl); 1047 _workers->threads_do(&cl); 1048 } 1049 1050 void ShenandoahHeap::collect(GCCause::Cause cause) { 1051 _control_thread->request_gc(cause); 1052 } 1053 1054 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1055 //assert(false, "Shouldn't need to do full collections"); 1056 } 1057 1058 CollectorPolicy* ShenandoahHeap::collector_policy() const { 1059 return _shenandoah_policy; 1060 } 1061 1062 void ShenandoahHeap::resize_tlabs() { 1063 CollectedHeap::resize_all_tlabs(); 1064 } 1065 1066 void ShenandoahHeap::accumulate_statistics_tlabs() { 1067 CollectedHeap::accumulate_statistics_all_tlabs(); 1068 } 1069 1070 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1071 Space* sp = heap_region_containing(addr); 1072 if (sp != NULL) { 1073 return sp->block_start(addr); 1074 } 1075 return NULL; 1076 } 1077 1078 size_t ShenandoahHeap::block_size(const HeapWord* addr) const { 1079 Space* sp = heap_region_containing(addr); 1080 assert(sp != NULL, "block_size of address outside of heap"); 1081 return sp->block_size(addr); 1082 } 1083 1084 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1085 Space* sp = heap_region_containing(addr); 1086 return sp->block_is_obj(addr); 1087 } 1088 1089 jlong ShenandoahHeap::millis_since_last_gc() { 1090 double v = heuristics()->time_since_last_gc() * 1000; 1091 assert(0 <= v && v <= max_jlong, err_msg("value should fit: %f", v)); 1092 return (jlong)v; 1093 } 1094 1095 void ShenandoahHeap::prepare_for_verify() { 1096 if (SafepointSynchronize::is_at_safepoint()) { 1097 make_parsable(false); 1098 } 1099 } 1100 1101 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1102 workers()->print_worker_threads_on(st); 1103 if (ShenandoahStringDedup::is_enabled()) { 1104 ShenandoahStringDedup::print_worker_threads_on(st); 1105 } 1106 } 1107 1108 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1109 workers()->threads_do(tcl); 1110 if (ShenandoahStringDedup::is_enabled()) { 1111 ShenandoahStringDedup::threads_do(tcl); 1112 } 1113 } 1114 1115 void ShenandoahHeap::print_tracing_info() const { 1116 if (PrintGC || TraceGen0Time || TraceGen1Time) { 1117 ResourceMark rm; 1118 outputStream* out = gclog_or_tty; 1119 phase_timings()->print_on(out); 1120 1121 out->cr(); 1122 out->cr(); 1123 1124 shenandoah_policy()->print_gc_stats(out); 1125 1126 out->cr(); 1127 out->cr(); 1128 1129 if (ShenandoahPacing) { 1130 pacer()->print_on(out); 1131 } 1132 1133 out->cr(); 1134 out->cr(); 1135 1136 if (ShenandoahAllocationTrace) { 1137 assert(alloc_tracker() != NULL, "Must be"); 1138 alloc_tracker()->print_on(out); 1139 } else { 1140 out->print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); 1141 } 1142 } 1143 } 1144 1145 void ShenandoahHeap::verify(bool silent, VerifyOption vo) { 1146 if (ShenandoahSafepoint::is_at_shenandoah_safepoint() || ! UseTLAB) { 1147 if (ShenandoahVerify) { 1148 verifier()->verify_generic(vo); 1149 } else { 1150 // TODO: Consider allocating verification bitmaps on demand, 1151 // and turn this on unconditionally. 1152 } 1153 } 1154 } 1155 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1156 return _free_set->capacity(); 1157 } 1158 1159 class ObjectIterateScanRootClosure : public ExtendedOopClosure { 1160 private: 1161 MarkBitMap* _bitmap; 1162 Stack<oop,mtGC>* _oop_stack; 1163 1164 template <class T> 1165 void do_oop_work(T* p) { 1166 T o = oopDesc::load_heap_oop(p); 1167 if (!oopDesc::is_null(o)) { 1168 oop obj = oopDesc::decode_heap_oop_not_null(o); 1169 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 1170 if (fwd == NULL) { 1171 // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp. 1172 // 1173 // That operation walks the reachable objects on its own, storing the marking 1174 // wavefront in the object marks. When it is done, it calls the CollectedHeap 1175 // to iterate over all objects to clean up the mess. When it reaches here, 1176 // the Shenandoah fwdptr resolution code encounters the marked objects with 1177 // NULL forwardee. Trying to act on that would crash the VM. Or fail the 1178 // asserts, should we go for resolve_forwarded_pointer(obj). 1179 // 1180 // Therefore, we have to dodge it by doing the raw access to forwardee, and 1181 // assuming the object had no forwardee, if that thing is NULL. 1182 } else { 1183 obj = fwd; 1184 } 1185 assert(obj->is_oop(), "must be a valid oop"); 1186 if (!_bitmap->isMarked((HeapWord*) obj)) { 1187 _bitmap->mark((HeapWord*) obj); 1188 _oop_stack->push(obj); 1189 } 1190 } 1191 } 1192 public: 1193 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1194 _bitmap(bitmap), _oop_stack(oop_stack) {} 1195 void do_oop(oop* p) { do_oop_work(p); } 1196 void do_oop(narrowOop* p) { do_oop_work(p); } 1197 }; 1198 1199 /* 1200 * This is public API, used in preparation of object_iterate(). 1201 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1202 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1203 * control, we call SH::make_parsable(). 1204 */ 1205 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1206 // No-op. 1207 } 1208 1209 /* 1210 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1211 * 1212 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1213 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1214 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1215 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1216 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1217 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1218 * wiped the bitmap in preparation for next marking). 1219 * 1220 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1221 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1222 * is allowed to report dead objects, but is not required to do so. 1223 */ 1224 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1225 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1226 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1227 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1228 return; 1229 } 1230 1231 // Reset bitmap 1232 _aux_bit_map.clear(); 1233 1234 Stack<oop,mtGC> oop_stack; 1235 1236 // First, we process all GC roots. This populates the work stack with initial objects. 1237 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases); 1238 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1239 CLDToOopClosure clds(&oops, false); 1240 CodeBlobToOopClosure blobs(&oops, false); 1241 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0); 1242 1243 // Work through the oop stack to traverse heap. 1244 while (! oop_stack.is_empty()) { 1245 oop obj = oop_stack.pop(); 1246 assert(obj->is_oop(), "must be a valid oop"); 1247 cl->do_object(obj); 1248 obj->oop_iterate(&oops); 1249 } 1250 1251 assert(oop_stack.is_empty(), "should be empty"); 1252 1253 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1254 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1255 } 1256 } 1257 1258 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) { 1259 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1260 object_iterate(cl); 1261 } 1262 1263 void ShenandoahHeap::oop_iterate(ExtendedOopClosure* cl) { 1264 ObjectToOopClosure cl2(cl); 1265 object_iterate(&cl2); 1266 } 1267 1268 class ShenandoahSpaceClosureRegionClosure: public ShenandoahHeapRegionClosure { 1269 SpaceClosure* _cl; 1270 public: 1271 ShenandoahSpaceClosureRegionClosure(SpaceClosure* cl) : _cl(cl) {} 1272 void heap_region_do(ShenandoahHeapRegion* r) { 1273 _cl->do_space(r); 1274 } 1275 }; 1276 1277 void ShenandoahHeap::space_iterate(SpaceClosure* cl) { 1278 ShenandoahSpaceClosureRegionClosure blk(cl); 1279 heap_region_iterate(&blk); 1280 } 1281 1282 Space* ShenandoahHeap::space_containing(const void* oop) const { 1283 Space* res = heap_region_containing(oop); 1284 return res; 1285 } 1286 1287 void ShenandoahHeap::gc_prologue(bool b) { 1288 Unimplemented(); 1289 } 1290 1291 void ShenandoahHeap::gc_epilogue(bool b) { 1292 Unimplemented(); 1293 } 1294 1295 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1296 for (size_t i = 0; i < num_regions(); i++) { 1297 ShenandoahHeapRegion* current = get_region(i); 1298 blk->heap_region_do(current); 1299 } 1300 } 1301 1302 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1303 private: 1304 ShenandoahHeap* const _heap; 1305 ShenandoahHeapRegionClosure* const _blk; 1306 1307 char _pad0[DEFAULT_CACHE_LINE_SIZE]; 1308 volatile jint _index; 1309 char _pad1[DEFAULT_CACHE_LINE_SIZE]; 1310 1311 public: 1312 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1313 AbstractGangTask("Parallel Region Task"), 1314 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1315 1316 void work(uint worker_id) { 1317 jint stride = (jint)ShenandoahParallelRegionStride; 1318 1319 jint max = (jint)_heap->num_regions(); 1320 while (_index < max) { 1321 jint cur = Atomic::add(stride, &_index) - stride; 1322 jint start = cur; 1323 jint end = MIN2(cur + stride, max); 1324 if (start >= max) break; 1325 1326 for (jint i = cur; i < end; i++) { 1327 ShenandoahHeapRegion* current = _heap->get_region((size_t)i); 1328 _blk->heap_region_do(current); 1329 } 1330 } 1331 } 1332 }; 1333 1334 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1335 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1336 if (num_regions() > ShenandoahParallelRegionStride) { 1337 ShenandoahParallelHeapRegionTask task(blk); 1338 workers()->run_task(&task); 1339 } else { 1340 heap_region_iterate(blk); 1341 } 1342 } 1343 1344 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { 1345 private: 1346 ShenandoahMarkingContext* const _ctx; 1347 public: 1348 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1349 1350 void heap_region_do(ShenandoahHeapRegion* r) { 1351 if (r->is_active()) { 1352 r->clear_live_data(); 1353 _ctx->capture_top_at_mark_start(r); 1354 } else { 1355 assert(!r->has_live(), 1356 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number())); 1357 assert(_ctx->top_at_mark_start(r) == r->top(), 1358 err_msg("Region " SIZE_FORMAT " should already have correct TAMS", r->region_number())); 1359 } 1360 } 1361 1362 bool is_thread_safe() { return true; } 1363 }; 1364 1365 void ShenandoahHeap::op_init_mark() { 1366 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1367 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1368 1369 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1370 assert(!marking_context()->is_complete(), "should not be complete"); 1371 1372 if (ShenandoahVerify) { 1373 verifier()->verify_before_concmark(); 1374 } 1375 1376 { 1377 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats); 1378 accumulate_statistics_tlabs(); 1379 } 1380 1381 if (VerifyBeforeGC) { 1382 Universe::verify(); 1383 } 1384 1385 set_concurrent_mark_in_progress(true); 1386 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1387 if (UseTLAB) { 1388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1389 make_parsable(true); 1390 } 1391 1392 { 1393 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); 1394 ShenandoahClearLivenessClosure clc; 1395 parallel_heap_region_iterate(&clc); 1396 } 1397 1398 // Make above changes visible to worker threads 1399 OrderAccess::fence(); 1400 1401 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1402 1403 if (UseTLAB) { 1404 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1405 resize_tlabs(); 1406 } 1407 1408 if (ShenandoahPacing) { 1409 pacer()->setup_for_mark(); 1410 } 1411 } 1412 1413 void ShenandoahHeap::op_mark() { 1414 concurrent_mark()->mark_from_roots(); 1415 } 1416 1417 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { 1418 private: 1419 ShenandoahMarkingContext* const _ctx; 1420 public: 1421 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} 1422 1423 void heap_region_do(ShenandoahHeapRegion* r) { 1424 if (r->is_active()) { 1425 HeapWord *tams = _ctx->top_at_mark_start(r); 1426 HeapWord *top = r->top(); 1427 if (top > tams) { 1428 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1429 } 1430 } else { 1431 assert(!r->has_live(), 1432 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number())); 1433 assert(_ctx->top_at_mark_start(r) == r->top(), 1434 err_msg("Region " SIZE_FORMAT " should have correct TAMS", r->region_number())); 1435 } 1436 } 1437 1438 bool is_thread_safe() { return true; } 1439 }; 1440 1441 void ShenandoahHeap::op_final_mark() { 1442 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1443 1444 // It is critical that we 1445 // evacuate roots right after finishing marking, so that we don't 1446 // get unmarked objects in the roots. 1447 1448 if (!cancelled_gc()) { 1449 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); 1450 1451 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->reset_taskqueue_stats()); 1452 1453 if (has_forwarded_objects()) { 1454 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots); 1455 } 1456 1457 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->print_taskqueue_stats()); 1458 1459 stop_concurrent_marking(); 1460 1461 { 1462 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); 1463 1464 // All allocations past TAMS are implicitly live, adjust the region data. 1465 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1466 ShenandoahCompleteLivenessClosure cl; 1467 parallel_heap_region_iterate(&cl); 1468 } 1469 1470 { 1471 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac); 1472 1473 make_parsable(true); 1474 1475 trash_cset_regions(); 1476 1477 { 1478 ShenandoahHeapLocker locker(lock()); 1479 _collection_set->clear(); 1480 _free_set->clear(); 1481 1482 heuristics()->choose_collection_set(_collection_set); 1483 _free_set->rebuild(); 1484 } 1485 } 1486 1487 // If collection set has candidates, start evacuation. 1488 // Otherwise, bypass the rest of the cycle. 1489 if (!collection_set()->is_empty()) { 1490 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1491 1492 if (ShenandoahVerify) { 1493 verifier()->verify_before_evacuation(); 1494 } 1495 1496 set_evacuation_in_progress(true); 1497 // From here on, we need to update references. 1498 set_has_forwarded_objects(true); 1499 1500 evacuate_and_update_roots(); 1501 1502 if (ShenandoahPacing) { 1503 pacer()->setup_for_evac(); 1504 } 1505 1506 if (ShenandoahVerify) { 1507 verifier()->verify_during_evacuation(); 1508 } 1509 } else { 1510 if (ShenandoahVerify) { 1511 verifier()->verify_after_concmark(); 1512 } 1513 1514 if (VerifyAfterGC) { 1515 Universe::verify(); 1516 } 1517 } 1518 1519 } else { 1520 concurrent_mark()->cancel(); 1521 stop_concurrent_marking(); 1522 1523 if (process_references()) { 1524 // Abandon reference processing right away: pre-cleaning must have failed. 1525 ReferenceProcessor *rp = ref_processor(); 1526 rp->disable_discovery(); 1527 rp->abandon_partial_discovery(); 1528 rp->verify_no_references_recorded(); 1529 } 1530 } 1531 } 1532 1533 void ShenandoahHeap::op_final_evac() { 1534 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1535 1536 set_evacuation_in_progress(false); 1537 if (ShenandoahVerify) { 1538 verifier()->verify_after_evacuation(); 1539 } 1540 1541 if (VerifyAfterGC) { 1542 Universe::verify(); 1543 } 1544 } 1545 1546 void ShenandoahHeap::op_conc_evac() { 1547 ShenandoahEvacuationTask task(this, _collection_set, true); 1548 workers()->run_task(&task); 1549 } 1550 1551 void ShenandoahHeap::op_stw_evac() { 1552 ShenandoahEvacuationTask task(this, _collection_set, false); 1553 workers()->run_task(&task); 1554 } 1555 1556 void ShenandoahHeap::op_updaterefs() { 1557 update_heap_references(true); 1558 } 1559 1560 void ShenandoahHeap::op_cleanup() { 1561 free_set()->recycle_trash(); 1562 } 1563 1564 void ShenandoahHeap::op_reset() { 1565 reset_mark_bitmap(); 1566 } 1567 1568 void ShenandoahHeap::op_preclean() { 1569 concurrent_mark()->preclean_weak_refs(); 1570 } 1571 1572 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1573 ShenandoahMetricsSnapshot metrics; 1574 metrics.snap_before(); 1575 1576 full_gc()->do_it(cause); 1577 1578 metrics.snap_after(); 1579 metrics.print(); 1580 1581 if (metrics.is_good_progress("Full GC")) { 1582 _progress_last_gc.set(); 1583 } else { 1584 // Nothing to do. Tell the allocation path that we have failed to make 1585 // progress, and it can finally fail. 1586 _progress_last_gc.unset(); 1587 } 1588 } 1589 1590 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1591 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1592 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1593 // some phase, we have to upgrade the Degenerate GC to Full GC. 1594 1595 clear_cancelled_gc(); 1596 1597 ShenandoahMetricsSnapshot metrics; 1598 metrics.snap_before(); 1599 1600 switch (point) { 1601 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1602 // but enters it at different points, depending on which concurrent phase had 1603 // degenerated. 1604 1605 case _degenerated_outside_cycle: 1606 // We have degenerated from outside the cycle, which means something is bad with 1607 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1608 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1609 // we can do the most aggressive degen cycle, which includes processing references and 1610 // class unloading, unless those features are explicitly disabled. 1611 // 1612 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1613 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1614 set_process_references(heuristics()->can_process_references()); 1615 set_unload_classes(heuristics()->can_unload_classes()); 1616 1617 op_reset(); 1618 1619 op_init_mark(); 1620 if (cancelled_gc()) { 1621 op_degenerated_fail(); 1622 return; 1623 } 1624 1625 case _degenerated_mark: 1626 op_final_mark(); 1627 if (cancelled_gc()) { 1628 op_degenerated_fail(); 1629 return; 1630 } 1631 1632 op_cleanup(); 1633 1634 case _degenerated_evac: 1635 // If heuristics thinks we should do the cycle, this flag would be set, 1636 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1637 if (is_evacuation_in_progress()) { 1638 1639 // Degeneration under oom-evac protocol might have left some objects in 1640 // collection set un-evacuated. Restart evacuation from the beginning to 1641 // capture all objects. For all the objects that are already evacuated, 1642 // it would be a simple check, which is supposed to be fast. This is also 1643 // safe to do even without degeneration, as CSet iterator is at beginning 1644 // in preparation for evacuation anyway. 1645 collection_set()->clear_current_index(); 1646 1647 op_stw_evac(); 1648 if (cancelled_gc()) { 1649 op_degenerated_fail(); 1650 return; 1651 } 1652 } 1653 1654 // If heuristics thinks we should do the cycle, this flag would be set, 1655 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1656 if (has_forwarded_objects()) { 1657 op_init_updaterefs(); 1658 if (cancelled_gc()) { 1659 op_degenerated_fail(); 1660 return; 1661 } 1662 } 1663 1664 case _degenerated_updaterefs: 1665 if (has_forwarded_objects()) { 1666 op_final_updaterefs(); 1667 if (cancelled_gc()) { 1668 op_degenerated_fail(); 1669 return; 1670 } 1671 } 1672 1673 op_cleanup(); 1674 break; 1675 1676 default: 1677 ShouldNotReachHere(); 1678 } 1679 1680 if (ShenandoahVerify) { 1681 verifier()->verify_after_degenerated(); 1682 } 1683 1684 if (VerifyAfterGC) { 1685 Universe::verify(); 1686 } 1687 1688 metrics.snap_after(); 1689 metrics.print(); 1690 1691 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 1692 // because that probably means the heap is overloaded and/or fragmented. 1693 if (!metrics.is_good_progress("Degenerated GC")) { 1694 _progress_last_gc.unset(); 1695 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1696 op_degenerated_futile(); 1697 } else { 1698 _progress_last_gc.set(); 1699 } 1700 } 1701 1702 void ShenandoahHeap::op_degenerated_fail() { 1703 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 1704 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1705 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1706 } 1707 1708 void ShenandoahHeap::op_degenerated_futile() { 1709 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1710 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1711 } 1712 1713 void ShenandoahHeap::stop_concurrent_marking() { 1714 assert(is_concurrent_mark_in_progress(), "How else could we get here?"); 1715 if (!cancelled_gc()) { 1716 // If we needed to update refs, and concurrent marking has been cancelled, 1717 // we need to finish updating references. 1718 set_has_forwarded_objects(false); 1719 mark_complete_marking_context(); 1720 } 1721 set_concurrent_mark_in_progress(false); 1722 } 1723 1724 void ShenandoahHeap::force_satb_flush_all_threads() { 1725 if (!is_concurrent_mark_in_progress()) { 1726 // No need to flush SATBs 1727 return; 1728 } 1729 1730 // Do not block if Threads lock is busy. This avoids the potential deadlock 1731 // when this code is called from the periodic task, and something else is 1732 // expecting the periodic task to complete without blocking. On the off-chance 1733 // Threads lock is busy momentarily, try to acquire several times. 1734 for (int t = 0; t < 10; t++) { 1735 if (Threads_lock->try_lock()) { 1736 JavaThread::set_force_satb_flush_all_threads(true); 1737 Threads_lock->unlock(); 1738 1739 // The threads are not "acquiring" their thread-local data, but it does not 1740 // hurt to "release" the updates here anyway. 1741 OrderAccess::fence(); 1742 break; 1743 } 1744 os::naked_short_sleep(1); 1745 } 1746 } 1747 1748 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1749 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1750 _gc_state.set_cond(mask, value); 1751 JavaThread::set_gc_state_all_threads(_gc_state.raw_value()); 1752 } 1753 1754 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1755 set_gc_state_mask(MARKING, in_progress); 1756 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1757 } 1758 1759 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1760 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1761 set_gc_state_mask(EVACUATION, in_progress); 1762 } 1763 1764 void ShenandoahHeap::ref_processing_init() { 1765 MemRegion mr = reserved_region(); 1766 1767 assert(_max_workers > 0, "Sanity"); 1768 1769 _ref_processor = 1770 new ReferenceProcessor(mr, // span 1771 ParallelRefProcEnabled, // MT processing 1772 _max_workers, // Degree of MT processing 1773 true, // MT discovery 1774 _max_workers, // Degree of MT discovery 1775 false, // Reference discovery is not atomic 1776 NULL); // No closure, should be installed before use 1777 1778 shenandoah_assert_rp_isalive_not_installed(); 1779 } 1780 1781 void ShenandoahHeap::acquire_pending_refs_lock() { 1782 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::acquirePLL); 1783 } 1784 1785 void ShenandoahHeap::release_pending_refs_lock() { 1786 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL); 1787 } 1788 1789 GCTracer* ShenandoahHeap::tracer() { 1790 return shenandoah_policy()->tracer(); 1791 } 1792 1793 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1794 return _free_set->used(); 1795 } 1796 1797 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 1798 if (try_cancel_gc()) { 1799 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 1800 log_info(gc)("%s", msg.buffer()); 1801 Events::log(Thread::current(), "%s", msg.buffer()); 1802 } 1803 } 1804 1805 uint ShenandoahHeap::max_workers() { 1806 return _max_workers; 1807 } 1808 1809 void ShenandoahHeap::stop() { 1810 // The shutdown sequence should be able to terminate when GC is running. 1811 1812 // Step 0. Notify policy to disable event recording. 1813 _shenandoah_policy->record_shutdown(); 1814 1815 // Step 1. Notify control thread that we are in shutdown. 1816 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 1817 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 1818 _control_thread->prepare_for_graceful_shutdown(); 1819 1820 // Step 2. Notify GC workers that we are cancelling GC. 1821 cancel_gc(GCCause::_shenandoah_stop_vm); 1822 1823 // Step 3. Wait until GC worker exits normally. 1824 _control_thread->stop(); 1825 1826 // Step 4. Stop String Dedup thread if it is active 1827 if (ShenandoahStringDedup::is_enabled()) { 1828 ShenandoahStringDedup::stop(); 1829 } 1830 } 1831 1832 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) { 1833 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled"); 1834 1835 ShenandoahGCPhase root_phase(full_gc ? 1836 ShenandoahPhaseTimings::full_gc_purge : 1837 ShenandoahPhaseTimings::purge); 1838 1839 ShenandoahIsAliveSelector alive; 1840 BoolObjectClosure* is_alive = alive.is_alive_closure(); 1841 1842 bool purged_class; 1843 1844 // Unload classes and purge SystemDictionary. 1845 { 1846 ShenandoahGCPhase phase(full_gc ? 1847 ShenandoahPhaseTimings::full_gc_purge_class_unload : 1848 ShenandoahPhaseTimings::purge_class_unload); 1849 purged_class = SystemDictionary::do_unloading(is_alive, 1850 full_gc /* do_cleaning*/ ); 1851 } 1852 1853 { 1854 ShenandoahGCPhase phase(full_gc ? 1855 ShenandoahPhaseTimings::full_gc_purge_par : 1856 ShenandoahPhaseTimings::purge_par); 1857 uint active = _workers->active_workers(); 1858 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class); 1859 _workers->run_task(&unlink_task); 1860 } 1861 1862 if (ShenandoahStringDedup::is_enabled()) { 1863 ShenandoahGCPhase phase(full_gc ? 1864 ShenandoahPhaseTimings::full_gc_purge_string_dedup : 1865 ShenandoahPhaseTimings::purge_string_dedup); 1866 ShenandoahStringDedup::parallel_cleanup(); 1867 } 1868 1869 { 1870 ShenandoahGCPhase phase(full_gc ? 1871 ShenandoahPhaseTimings::full_gc_purge_cldg : 1872 ShenandoahPhaseTimings::purge_cldg); 1873 ClassLoaderDataGraph::purge(); 1874 } 1875 } 1876 1877 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 1878 set_gc_state_mask(HAS_FORWARDED, cond); 1879 } 1880 1881 void ShenandoahHeap::set_process_references(bool pr) { 1882 _process_references.set_cond(pr); 1883 } 1884 1885 void ShenandoahHeap::set_unload_classes(bool uc) { 1886 _unload_classes.set_cond(uc); 1887 } 1888 1889 bool ShenandoahHeap::process_references() const { 1890 return _process_references.is_set(); 1891 } 1892 1893 bool ShenandoahHeap::unload_classes() const { 1894 return _unload_classes.is_set(); 1895 } 1896 1897 address ShenandoahHeap::in_cset_fast_test_addr() { 1898 ShenandoahHeap* heap = ShenandoahHeap::heap(); 1899 assert(heap->collection_set() != NULL, "Sanity"); 1900 return (address) heap->collection_set()->biased_map_address(); 1901 } 1902 1903 address ShenandoahHeap::cancelled_gc_addr() { 1904 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 1905 } 1906 1907 address ShenandoahHeap::gc_state_addr() { 1908 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 1909 } 1910 1911 size_t ShenandoahHeap::conservative_max_heap_alignment() { 1912 size_t align = ShenandoahMaxRegionSize; 1913 if (UseLargePages) { 1914 align = MAX2(align, os::large_page_size()); 1915 } 1916 return align; 1917 } 1918 1919 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 1920 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start); 1921 } 1922 1923 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 1924 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 1925 } 1926 1927 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 1928 _degenerated_gc_in_progress.set_cond(in_progress); 1929 } 1930 1931 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 1932 _full_gc_in_progress.set_cond(in_progress); 1933 } 1934 1935 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 1936 assert (is_full_gc_in_progress(), "should be"); 1937 _full_gc_move_in_progress.set_cond(in_progress); 1938 } 1939 1940 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 1941 set_gc_state_mask(UPDATEREFS, in_progress); 1942 } 1943 1944 void ShenandoahHeap::register_nmethod(nmethod* nm) { 1945 ShenandoahCodeRoots::add_nmethod(nm); 1946 } 1947 1948 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 1949 ShenandoahCodeRoots::remove_nmethod(nm); 1950 } 1951 1952 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 1953 ShenandoahHeapLocker locker(lock()); 1954 heap_region_containing(o)->make_pinned(); 1955 return o; 1956 } 1957 1958 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 1959 ShenandoahHeapLocker locker(lock()); 1960 heap_region_containing(o)->make_unpinned(); 1961 } 1962 1963 GCTimer* ShenandoahHeap::gc_timer() const { 1964 return _gc_timer; 1965 } 1966 1967 #ifdef ASSERT 1968 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 1969 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 1970 1971 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1972 if (UseDynamicNumberOfGCThreads || 1973 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { 1974 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 1975 } else { 1976 // Use ParallelGCThreads inside safepoints 1977 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); 1978 } 1979 } else { 1980 if (UseDynamicNumberOfGCThreads || 1981 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { 1982 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 1983 } else { 1984 // Use ConcGCThreads outside safepoints 1985 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 1986 } 1987 } 1988 } 1989 #endif 1990 1991 ShenandoahVerifier* ShenandoahHeap::verifier() { 1992 guarantee(ShenandoahVerify, "Should be enabled"); 1993 assert (_verifier != NULL, "sanity"); 1994 return _verifier; 1995 } 1996 1997 ShenandoahUpdateHeapRefsClosure::ShenandoahUpdateHeapRefsClosure() : 1998 _heap(ShenandoahHeap::heap()) {} 1999 2000 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2001 private: 2002 ShenandoahHeap* _heap; 2003 ShenandoahRegionIterator* _regions; 2004 bool _concurrent; 2005 2006 public: 2007 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2008 AbstractGangTask("Concurrent Update References Task"), 2009 _heap(ShenandoahHeap::heap()), 2010 _regions(regions), 2011 _concurrent(concurrent) { 2012 } 2013 2014 void work(uint worker_id) { 2015 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2016 ShenandoahUpdateHeapRefsClosure cl; 2017 ShenandoahHeapRegion* r = _regions->next(); 2018 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2019 while (r != NULL) { 2020 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); 2021 assert (top_at_start_ur >= r->bottom(), "sanity"); 2022 if (r->is_active() && !r->is_cset()) { 2023 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); 2024 } 2025 if (ShenandoahPacing) { 2026 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); 2027 } 2028 if (_heap->cancelled_gc()) { 2029 return; 2030 } 2031 r = _regions->next(); 2032 } 2033 } 2034 }; 2035 2036 void ShenandoahHeap::update_heap_references(bool concurrent) { 2037 ShenandoahUpdateHeapRefsTask task(&_update_refs_iterator, concurrent); 2038 workers()->run_task(&task); 2039 } 2040 2041 void ShenandoahHeap::op_init_updaterefs() { 2042 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2043 2044 set_evacuation_in_progress(false); 2045 2046 if (ShenandoahVerify) { 2047 verifier()->verify_before_updaterefs(); 2048 } 2049 2050 set_update_refs_in_progress(true); 2051 make_parsable(true); 2052 for (uint i = 0; i < num_regions(); i++) { 2053 ShenandoahHeapRegion* r = get_region(i); 2054 r->set_concurrent_iteration_safe_limit(r->top()); 2055 } 2056 2057 // Reset iterator. 2058 _update_refs_iterator.reset(); 2059 2060 if (ShenandoahPacing) { 2061 pacer()->setup_for_updaterefs(); 2062 } 2063 } 2064 2065 void ShenandoahHeap::op_final_updaterefs() { 2066 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2067 2068 // Check if there is left-over work, and finish it 2069 if (_update_refs_iterator.has_next()) { 2070 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work); 2071 2072 // Finish updating references where we left off. 2073 clear_cancelled_gc(); 2074 update_heap_references(false); 2075 } 2076 2077 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2078 // everything. On degenerated paths, cancelled gc would not be set anyway. 2079 if (cancelled_gc()) { 2080 clear_cancelled_gc(); 2081 } 2082 assert(!cancelled_gc(), "Should have been done right before"); 2083 2084 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ? 2085 ShenandoahPhaseTimings::degen_gc_update_roots: 2086 ShenandoahPhaseTimings::final_update_refs_roots); 2087 2088 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle); 2089 2090 trash_cset_regions(); 2091 set_has_forwarded_objects(false); 2092 set_update_refs_in_progress(false); 2093 2094 if (ShenandoahVerify) { 2095 verifier()->verify_after_updaterefs(); 2096 } 2097 2098 if (VerifyAfterGC) { 2099 Universe::verify(); 2100 } 2101 2102 { 2103 ShenandoahHeapLocker locker(lock()); 2104 _free_set->rebuild(); 2105 } 2106 } 2107 2108 #ifdef ASSERT 2109 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { 2110 _lock.assert_not_owned_by_current_thread(); 2111 } 2112 2113 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { 2114 _lock.assert_owned_by_current_thread(); 2115 } 2116 2117 void ShenandoahHeap::assert_heaplock_or_safepoint() { 2118 _lock.assert_owned_by_current_thread_or_safepoint(); 2119 } 2120 #endif 2121 2122 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2123 print_on(st); 2124 print_heap_regions_on(st); 2125 } 2126 2127 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2128 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2129 2130 size_t regions_from = _bitmap_regions_per_slice * slice; 2131 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2132 for (size_t g = regions_from; g < regions_to; g++) { 2133 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2134 if (skip_self && g == r->region_number()) continue; 2135 if (get_region(g)->is_committed()) { 2136 return true; 2137 } 2138 } 2139 return false; 2140 } 2141 2142 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2143 assert_heaplock_owned_by_current_thread(); 2144 2145 // Bitmaps in special regions do not need commits 2146 if (_bitmap_region_special) { 2147 return true; 2148 } 2149 2150 if (is_bitmap_slice_committed(r, true)) { 2151 // Some other region from the group is already committed, meaning the bitmap 2152 // slice is already committed, we exit right away. 2153 return true; 2154 } 2155 2156 // Commit the bitmap slice: 2157 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2158 size_t off = _bitmap_bytes_per_slice * slice; 2159 size_t len = _bitmap_bytes_per_slice; 2160 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2161 return false; 2162 } 2163 return true; 2164 } 2165 2166 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2167 assert_heaplock_owned_by_current_thread(); 2168 2169 // Bitmaps in special regions do not need uncommits 2170 if (_bitmap_region_special) { 2171 return true; 2172 } 2173 2174 if (is_bitmap_slice_committed(r, true)) { 2175 // Some other region from the group is still committed, meaning the bitmap 2176 // slice is should stay committed, exit right away. 2177 return true; 2178 } 2179 2180 // Uncommit the bitmap slice: 2181 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2182 size_t off = _bitmap_bytes_per_slice * slice; 2183 size_t len = _bitmap_bytes_per_slice; 2184 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2185 return false; 2186 } 2187 return true; 2188 } 2189 2190 void ShenandoahHeap::vmop_entry_init_mark() { 2191 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2192 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2193 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2194 2195 try_inject_alloc_failure(); 2196 VM_ShenandoahInitMark op; 2197 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2198 } 2199 2200 void ShenandoahHeap::vmop_entry_final_mark() { 2201 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2202 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2203 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2204 2205 try_inject_alloc_failure(); 2206 VM_ShenandoahFinalMarkStartEvac op; 2207 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2208 } 2209 2210 void ShenandoahHeap::vmop_entry_final_evac() { 2211 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2212 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2213 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); 2214 2215 VM_ShenandoahFinalEvac op; 2216 VMThread::execute(&op); // jump to entry_final_evac under safepoint 2217 } 2218 2219 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2220 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2221 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2222 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2223 2224 try_inject_alloc_failure(); 2225 VM_ShenandoahInitUpdateRefs op; 2226 VMThread::execute(&op); 2227 } 2228 2229 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2230 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2231 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2232 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2233 2234 try_inject_alloc_failure(); 2235 VM_ShenandoahFinalUpdateRefs op; 2236 VMThread::execute(&op); 2237 } 2238 2239 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2240 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2241 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2242 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2243 2244 try_inject_alloc_failure(); 2245 VM_ShenandoahFullGC op(cause); 2246 VMThread::execute(&op); 2247 } 2248 2249 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2250 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2251 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2252 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2253 2254 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2255 VMThread::execute(°enerated_gc); 2256 } 2257 2258 void ShenandoahHeap::entry_init_mark() { 2259 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2260 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2261 2262 const char* msg = init_mark_event_message(); 2263 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2264 EventMark em("%s", msg); 2265 2266 ShenandoahWorkerScope scope(workers(), 2267 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2268 "init marking"); 2269 2270 op_init_mark(); 2271 } 2272 2273 void ShenandoahHeap::entry_final_mark() { 2274 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2275 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2276 2277 const char* msg = final_mark_event_message(); 2278 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2279 EventMark em("%s", msg); 2280 2281 ShenandoahWorkerScope scope(workers(), 2282 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2283 "final marking"); 2284 2285 op_final_mark(); 2286 } 2287 2288 void ShenandoahHeap::entry_final_evac() { 2289 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2290 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); 2291 2292 const char* msg = "Pause Final Evac"; 2293 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2294 EventMark em("%s", msg); 2295 2296 op_final_evac(); 2297 } 2298 2299 void ShenandoahHeap::entry_init_updaterefs() { 2300 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2301 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2302 2303 static const char* msg = "Pause Init Update Refs"; 2304 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2305 EventMark em("%s", msg); 2306 2307 // No workers used in this phase, no setup required 2308 2309 op_init_updaterefs(); 2310 } 2311 2312 void ShenandoahHeap::entry_final_updaterefs() { 2313 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2314 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2315 2316 static const char* msg = "Pause Final Update Refs"; 2317 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2318 EventMark em("%s", msg); 2319 2320 ShenandoahWorkerScope scope(workers(), 2321 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2322 "final reference update"); 2323 2324 op_final_updaterefs(); 2325 } 2326 2327 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2328 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2329 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2330 2331 static const char* msg = "Pause Full"; 2332 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true); 2333 EventMark em("%s", msg); 2334 2335 ShenandoahWorkerScope scope(workers(), 2336 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2337 "full gc"); 2338 2339 op_full(cause); 2340 } 2341 2342 void ShenandoahHeap::entry_degenerated(int point) { 2343 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2344 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2345 2346 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2347 const char* msg = degen_event_message(dpoint); 2348 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true); 2349 EventMark em("%s", msg); 2350 2351 ShenandoahWorkerScope scope(workers(), 2352 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2353 "stw degenerated gc"); 2354 2355 set_degenerated_gc_in_progress(true); 2356 op_degenerated(dpoint); 2357 set_degenerated_gc_in_progress(false); 2358 } 2359 2360 void ShenandoahHeap::entry_mark() { 2361 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2362 2363 const char* msg = conc_mark_event_message(); 2364 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2365 EventMark em("%s", msg); 2366 2367 ShenandoahWorkerScope scope(workers(), 2368 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2369 "concurrent marking"); 2370 2371 try_inject_alloc_failure(); 2372 op_mark(); 2373 } 2374 2375 void ShenandoahHeap::entry_evac() { 2376 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2377 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2378 2379 static const char *msg = "Concurrent evacuation"; 2380 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2381 EventMark em("%s", msg); 2382 2383 ShenandoahWorkerScope scope(workers(), 2384 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2385 "concurrent evacuation"); 2386 2387 try_inject_alloc_failure(); 2388 op_conc_evac(); 2389 } 2390 2391 void ShenandoahHeap::entry_updaterefs() { 2392 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2393 2394 static const char* msg = "Concurrent update references"; 2395 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2396 EventMark em("%s", msg); 2397 2398 ShenandoahWorkerScope scope(workers(), 2399 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2400 "concurrent reference update"); 2401 2402 try_inject_alloc_failure(); 2403 op_updaterefs(); 2404 } 2405 2406 void ShenandoahHeap::entry_cleanup() { 2407 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2408 2409 static const char* msg = "Concurrent cleanup"; 2410 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2411 EventMark em("%s", msg); 2412 2413 // This phase does not use workers, no need for setup 2414 2415 try_inject_alloc_failure(); 2416 op_cleanup(); 2417 } 2418 2419 void ShenandoahHeap::entry_reset() { 2420 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2421 2422 static const char* msg = "Concurrent reset"; 2423 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2424 EventMark em("%s", msg); 2425 2426 ShenandoahWorkerScope scope(workers(), 2427 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2428 "concurrent reset"); 2429 2430 try_inject_alloc_failure(); 2431 op_reset(); 2432 } 2433 2434 void ShenandoahHeap::entry_preclean() { 2435 if (ShenandoahPreclean && process_references()) { 2436 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2437 2438 static const char* msg = "Concurrent precleaning"; 2439 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2440 EventMark em("%s", msg); 2441 2442 ShenandoahWorkerScope scope(workers(), 2443 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2444 "concurrent preclean", 2445 /* check_workers = */ false); 2446 2447 try_inject_alloc_failure(); 2448 op_preclean(); 2449 } 2450 } 2451 2452 void ShenandoahHeap::entry_uncommit(double shrink_before) { 2453 static const char *msg = "Concurrent uncommit"; 2454 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2455 EventMark em("%s", msg); 2456 2457 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 2458 2459 op_uncommit(shrink_before); 2460 } 2461 2462 void ShenandoahHeap::try_inject_alloc_failure() { 2463 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2464 _inject_alloc_failure.set(); 2465 os::naked_short_sleep(1); 2466 if (cancelled_gc()) { 2467 log_info(gc)("Allocation failure was successfully injected"); 2468 } 2469 } 2470 } 2471 2472 bool ShenandoahHeap::should_inject_alloc_failure() { 2473 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2474 } 2475 2476 void ShenandoahHeap::enter_evacuation() { 2477 _oom_evac_handler.enter_evacuation(); 2478 } 2479 2480 void ShenandoahHeap::leave_evacuation() { 2481 _oom_evac_handler.leave_evacuation(); 2482 } 2483 2484 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2485 _heap(ShenandoahHeap::heap()), 2486 _index(0) {} 2487 2488 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2489 _heap(heap), 2490 _index(0) {} 2491 2492 void ShenandoahRegionIterator::reset() { 2493 _index = 0; 2494 } 2495 2496 bool ShenandoahRegionIterator::has_next() const { 2497 return _index < (jint)_heap->num_regions(); 2498 } 2499 2500 char ShenandoahHeap::gc_state() { 2501 return _gc_state.raw_value(); 2502 } 2503 2504 const char* ShenandoahHeap::init_mark_event_message() const { 2505 bool update_refs = has_forwarded_objects(); 2506 bool proc_refs = process_references(); 2507 bool unload_cls = unload_classes(); 2508 2509 if (update_refs && proc_refs && unload_cls) { 2510 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; 2511 } else if (update_refs && proc_refs) { 2512 return "Pause Init Mark (update refs) (process weakrefs)"; 2513 } else if (update_refs && unload_cls) { 2514 return "Pause Init Mark (update refs) (unload classes)"; 2515 } else if (proc_refs && unload_cls) { 2516 return "Pause Init Mark (process weakrefs) (unload classes)"; 2517 } else if (update_refs) { 2518 return "Pause Init Mark (update refs)"; 2519 } else if (proc_refs) { 2520 return "Pause Init Mark (process weakrefs)"; 2521 } else if (unload_cls) { 2522 return "Pause Init Mark (unload classes)"; 2523 } else { 2524 return "Pause Init Mark"; 2525 } 2526 } 2527 2528 const char* ShenandoahHeap::final_mark_event_message() const { 2529 bool update_refs = has_forwarded_objects(); 2530 bool proc_refs = process_references(); 2531 bool unload_cls = unload_classes(); 2532 2533 if (update_refs && proc_refs && unload_cls) { 2534 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; 2535 } else if (update_refs && proc_refs) { 2536 return "Pause Final Mark (update refs) (process weakrefs)"; 2537 } else if (update_refs && unload_cls) { 2538 return "Pause Final Mark (update refs) (unload classes)"; 2539 } else if (proc_refs && unload_cls) { 2540 return "Pause Final Mark (process weakrefs) (unload classes)"; 2541 } else if (update_refs) { 2542 return "Pause Final Mark (update refs)"; 2543 } else if (proc_refs) { 2544 return "Pause Final Mark (process weakrefs)"; 2545 } else if (unload_cls) { 2546 return "Pause Final Mark (unload classes)"; 2547 } else { 2548 return "Pause Final Mark"; 2549 } 2550 } 2551 2552 const char* ShenandoahHeap::conc_mark_event_message() const { 2553 bool update_refs = has_forwarded_objects(); 2554 bool proc_refs = process_references(); 2555 bool unload_cls = unload_classes(); 2556 2557 if (update_refs && proc_refs && unload_cls) { 2558 return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; 2559 } else if (update_refs && proc_refs) { 2560 return "Concurrent marking (update refs) (process weakrefs)"; 2561 } else if (update_refs && unload_cls) { 2562 return "Concurrent marking (update refs) (unload classes)"; 2563 } else if (proc_refs && unload_cls) { 2564 return "Concurrent marking (process weakrefs) (unload classes)"; 2565 } else if (update_refs) { 2566 return "Concurrent marking (update refs)"; 2567 } else if (proc_refs) { 2568 return "Concurrent marking (process weakrefs)"; 2569 } else if (unload_cls) { 2570 return "Concurrent marking (unload classes)"; 2571 } else { 2572 return "Concurrent marking"; 2573 } 2574 } 2575 2576 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 2577 switch (point) { 2578 case _degenerated_unset: 2579 return "Pause Degenerated GC (<UNSET>)"; 2580 case _degenerated_outside_cycle: 2581 return "Pause Degenerated GC (Outside of Cycle)"; 2582 case _degenerated_mark: 2583 return "Pause Degenerated GC (Mark)"; 2584 case _degenerated_evac: 2585 return "Pause Degenerated GC (Evacuation)"; 2586 case _degenerated_updaterefs: 2587 return "Pause Degenerated GC (Update Refs)"; 2588 default: 2589 ShouldNotReachHere(); 2590 return "ERROR"; 2591 } 2592 } 2593 2594 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2595 #ifdef ASSERT 2596 assert(_liveness_cache != NULL, "sanity"); 2597 assert(worker_id < _max_workers, "sanity"); 2598 for (uint i = 0; i < num_regions(); i++) { 2599 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 2600 } 2601 #endif 2602 return _liveness_cache[worker_id]; 2603 } 2604 2605 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 2606 assert(worker_id < _max_workers, "sanity"); 2607 assert(_liveness_cache != NULL, "sanity"); 2608 jushort* ld = _liveness_cache[worker_id]; 2609 for (uint i = 0; i < num_regions(); i++) { 2610 ShenandoahHeapRegion* r = get_region(i); 2611 jushort live = ld[i]; 2612 if (live > 0) { 2613 r->increase_live_data_gc_words(live); 2614 ld[i] = 0; 2615 } 2616 } 2617 }