Ben Murdoch | 592a9fc | 2012-03-05 11:04:45 +0000 | [diff] [blame^] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #include "v8.h" |
| 29 | |
| 30 | #include "incremental-marking.h" |
| 31 | |
| 32 | #include "code-stubs.h" |
| 33 | #include "compilation-cache.h" |
| 34 | #include "v8conversions.h" |
| 35 | |
| 36 | namespace v8 { |
| 37 | namespace internal { |
| 38 | |
| 39 | |
| 40 | IncrementalMarking::IncrementalMarking(Heap* heap) |
| 41 | : heap_(heap), |
| 42 | state_(STOPPED), |
| 43 | marking_deque_memory_(NULL), |
| 44 | marking_deque_memory_committed_(false), |
| 45 | steps_count_(0), |
| 46 | steps_took_(0), |
| 47 | longest_step_(0.0), |
| 48 | old_generation_space_available_at_start_of_incremental_(0), |
| 49 | old_generation_space_used_at_start_of_incremental_(0), |
| 50 | steps_count_since_last_gc_(0), |
| 51 | steps_took_since_last_gc_(0), |
| 52 | should_hurry_(false), |
| 53 | allocation_marking_factor_(0), |
| 54 | allocated_(0), |
| 55 | no_marking_scope_depth_(0) { |
| 56 | } |
| 57 | |
| 58 | |
| 59 | void IncrementalMarking::TearDown() { |
| 60 | delete marking_deque_memory_; |
| 61 | } |
| 62 | |
| 63 | |
| 64 | void IncrementalMarking::RecordWriteSlow(HeapObject* obj, |
| 65 | Object** slot, |
| 66 | Object* value) { |
| 67 | if (BaseRecordWrite(obj, slot, value) && is_compacting_ && slot != NULL) { |
| 68 | MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| 69 | if (Marking::IsBlack(obj_bit)) { |
| 70 | // Object is not going to be rescanned we need to record the slot. |
| 71 | heap_->mark_compact_collector()->RecordSlot( |
| 72 | HeapObject::RawField(obj, 0), slot, value); |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | |
| 78 | void IncrementalMarking::RecordWriteFromCode(HeapObject* obj, |
| 79 | Object* value, |
| 80 | Isolate* isolate) { |
| 81 | ASSERT(obj->IsHeapObject()); |
| 82 | |
| 83 | // Fast cases should already be covered by RecordWriteStub. |
| 84 | ASSERT(value->IsHeapObject()); |
| 85 | ASSERT(!value->IsHeapNumber()); |
| 86 | ASSERT(!value->IsString() || |
| 87 | value->IsConsString() || |
| 88 | value->IsSlicedString()); |
| 89 | ASSERT(Marking::IsWhite(Marking::MarkBitFrom(HeapObject::cast(value)))); |
| 90 | |
| 91 | IncrementalMarking* marking = isolate->heap()->incremental_marking(); |
| 92 | ASSERT(!marking->is_compacting_); |
| 93 | marking->RecordWrite(obj, NULL, value); |
| 94 | } |
| 95 | |
| 96 | |
| 97 | void IncrementalMarking::RecordWriteForEvacuationFromCode(HeapObject* obj, |
| 98 | Object** slot, |
| 99 | Isolate* isolate) { |
| 100 | IncrementalMarking* marking = isolate->heap()->incremental_marking(); |
| 101 | ASSERT(marking->is_compacting_); |
| 102 | marking->RecordWrite(obj, slot, *slot); |
| 103 | } |
| 104 | |
| 105 | |
| 106 | void IncrementalMarking::RecordCodeTargetPatch(Code* host, |
| 107 | Address pc, |
| 108 | HeapObject* value) { |
| 109 | if (IsMarking()) { |
| 110 | RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host); |
| 111 | RecordWriteIntoCode(host, &rinfo, value); |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | |
| 116 | void IncrementalMarking::RecordCodeTargetPatch(Address pc, HeapObject* value) { |
| 117 | if (IsMarking()) { |
| 118 | Code* host = heap_->isolate()->inner_pointer_to_code_cache()-> |
| 119 | GcSafeFindCodeForInnerPointer(pc); |
| 120 | RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host); |
| 121 | RecordWriteIntoCode(host, &rinfo, value); |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | |
| 126 | void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host, |
| 127 | Object** slot, |
| 128 | Code* value) { |
| 129 | if (BaseRecordWrite(host, slot, value) && is_compacting_) { |
| 130 | ASSERT(slot != NULL); |
| 131 | heap_->mark_compact_collector()-> |
| 132 | RecordCodeEntrySlot(reinterpret_cast<Address>(slot), value); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | |
| 137 | void IncrementalMarking::RecordWriteIntoCodeSlow(HeapObject* obj, |
| 138 | RelocInfo* rinfo, |
| 139 | Object* value) { |
| 140 | MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value)); |
| 141 | if (Marking::IsWhite(value_bit)) { |
| 142 | MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| 143 | if (Marking::IsBlack(obj_bit)) { |
| 144 | BlackToGreyAndUnshift(obj, obj_bit); |
| 145 | RestartIfNotMarking(); |
| 146 | } |
| 147 | // Object is either grey or white. It will be scanned if survives. |
| 148 | return; |
| 149 | } |
| 150 | |
| 151 | if (is_compacting_) { |
| 152 | MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| 153 | if (Marking::IsBlack(obj_bit)) { |
| 154 | // Object is not going to be rescanned. We need to record the slot. |
| 155 | heap_->mark_compact_collector()->RecordRelocSlot(rinfo, |
| 156 | Code::cast(value)); |
| 157 | } |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | |
| 162 | class IncrementalMarkingMarkingVisitor : public ObjectVisitor { |
| 163 | public: |
| 164 | IncrementalMarkingMarkingVisitor(Heap* heap, |
| 165 | IncrementalMarking* incremental_marking) |
| 166 | : heap_(heap), |
| 167 | incremental_marking_(incremental_marking) { |
| 168 | } |
| 169 | |
| 170 | void VisitEmbeddedPointer(RelocInfo* rinfo) { |
| 171 | ASSERT(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT); |
| 172 | Object* target = rinfo->target_object(); |
| 173 | if (target->NonFailureIsHeapObject()) { |
| 174 | heap_->mark_compact_collector()->RecordRelocSlot(rinfo, target); |
| 175 | MarkObject(target); |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | void VisitCodeTarget(RelocInfo* rinfo) { |
| 180 | ASSERT(RelocInfo::IsCodeTarget(rinfo->rmode())); |
| 181 | Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address()); |
| 182 | heap_->mark_compact_collector()->RecordRelocSlot(rinfo, Code::cast(target)); |
| 183 | MarkObject(target); |
| 184 | } |
| 185 | |
| 186 | void VisitDebugTarget(RelocInfo* rinfo) { |
| 187 | ASSERT((RelocInfo::IsJSReturn(rinfo->rmode()) && |
| 188 | rinfo->IsPatchedReturnSequence()) || |
| 189 | (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) && |
| 190 | rinfo->IsPatchedDebugBreakSlotSequence())); |
| 191 | Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address()); |
| 192 | heap_->mark_compact_collector()->RecordRelocSlot(rinfo, Code::cast(target)); |
| 193 | MarkObject(target); |
| 194 | } |
| 195 | |
| 196 | void VisitCodeEntry(Address entry_address) { |
| 197 | Object* target = Code::GetObjectFromEntryAddress(entry_address); |
| 198 | heap_->mark_compact_collector()-> |
| 199 | RecordCodeEntrySlot(entry_address, Code::cast(target)); |
| 200 | MarkObject(target); |
| 201 | } |
| 202 | |
| 203 | void VisitPointer(Object** p) { |
| 204 | Object* obj = *p; |
| 205 | if (obj->NonFailureIsHeapObject()) { |
| 206 | heap_->mark_compact_collector()->RecordSlot(p, p, obj); |
| 207 | MarkObject(obj); |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | void VisitPointers(Object** start, Object** end) { |
| 212 | for (Object** p = start; p < end; p++) { |
| 213 | Object* obj = *p; |
| 214 | if (obj->NonFailureIsHeapObject()) { |
| 215 | heap_->mark_compact_collector()->RecordSlot(start, p, obj); |
| 216 | MarkObject(obj); |
| 217 | } |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | private: |
| 222 | // Mark object pointed to by p. |
| 223 | INLINE(void MarkObject(Object* obj)) { |
| 224 | HeapObject* heap_object = HeapObject::cast(obj); |
| 225 | MarkBit mark_bit = Marking::MarkBitFrom(heap_object); |
| 226 | if (mark_bit.data_only()) { |
| 227 | if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) { |
| 228 | MemoryChunk::IncrementLiveBytes(heap_object->address(), |
| 229 | heap_object->Size()); |
| 230 | } |
| 231 | } else if (Marking::IsWhite(mark_bit)) { |
| 232 | incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit); |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | Heap* heap_; |
| 237 | IncrementalMarking* incremental_marking_; |
| 238 | }; |
| 239 | |
| 240 | |
| 241 | class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor { |
| 242 | public: |
| 243 | IncrementalMarkingRootMarkingVisitor(Heap* heap, |
| 244 | IncrementalMarking* incremental_marking) |
| 245 | : heap_(heap), |
| 246 | incremental_marking_(incremental_marking) { |
| 247 | } |
| 248 | |
| 249 | void VisitPointer(Object** p) { |
| 250 | MarkObjectByPointer(p); |
| 251 | } |
| 252 | |
| 253 | void VisitPointers(Object** start, Object** end) { |
| 254 | for (Object** p = start; p < end; p++) MarkObjectByPointer(p); |
| 255 | } |
| 256 | |
| 257 | private: |
| 258 | void MarkObjectByPointer(Object** p) { |
| 259 | Object* obj = *p; |
| 260 | if (!obj->IsHeapObject()) return; |
| 261 | |
| 262 | HeapObject* heap_object = HeapObject::cast(obj); |
| 263 | MarkBit mark_bit = Marking::MarkBitFrom(heap_object); |
| 264 | if (mark_bit.data_only()) { |
| 265 | if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) { |
| 266 | MemoryChunk::IncrementLiveBytes(heap_object->address(), |
| 267 | heap_object->Size()); |
| 268 | } |
| 269 | } else { |
| 270 | if (Marking::IsWhite(mark_bit)) { |
| 271 | incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit); |
| 272 | } |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | Heap* heap_; |
| 277 | IncrementalMarking* incremental_marking_; |
| 278 | }; |
| 279 | |
| 280 | |
| 281 | void IncrementalMarking::SetOldSpacePageFlags(MemoryChunk* chunk, |
| 282 | bool is_marking, |
| 283 | bool is_compacting) { |
| 284 | if (is_marking) { |
| 285 | chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| 286 | chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| 287 | |
| 288 | // It's difficult to filter out slots recorded for large objects. |
| 289 | if (chunk->owner()->identity() == LO_SPACE && |
| 290 | chunk->size() > static_cast<size_t>(Page::kPageSize) && |
| 291 | is_compacting) { |
| 292 | chunk->SetFlag(MemoryChunk::RESCAN_ON_EVACUATION); |
| 293 | } |
| 294 | } else if (chunk->owner()->identity() == CELL_SPACE || |
| 295 | chunk->scan_on_scavenge()) { |
| 296 | chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| 297 | chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| 298 | } else { |
| 299 | chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| 300 | chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| 301 | } |
| 302 | } |
| 303 | |
| 304 | |
| 305 | void IncrementalMarking::SetNewSpacePageFlags(NewSpacePage* chunk, |
| 306 | bool is_marking) { |
| 307 | chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| 308 | if (is_marking) { |
| 309 | chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| 310 | } else { |
| 311 | chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| 312 | } |
| 313 | chunk->SetFlag(MemoryChunk::SCAN_ON_SCAVENGE); |
| 314 | } |
| 315 | |
| 316 | |
| 317 | void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace( |
| 318 | PagedSpace* space) { |
| 319 | PageIterator it(space); |
| 320 | while (it.has_next()) { |
| 321 | Page* p = it.next(); |
| 322 | SetOldSpacePageFlags(p, false, false); |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | |
| 327 | void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace( |
| 328 | NewSpace* space) { |
| 329 | NewSpacePageIterator it(space); |
| 330 | while (it.has_next()) { |
| 331 | NewSpacePage* p = it.next(); |
| 332 | SetNewSpacePageFlags(p, false); |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | |
| 337 | void IncrementalMarking::DeactivateIncrementalWriteBarrier() { |
| 338 | DeactivateIncrementalWriteBarrierForSpace(heap_->old_pointer_space()); |
| 339 | DeactivateIncrementalWriteBarrierForSpace(heap_->old_data_space()); |
| 340 | DeactivateIncrementalWriteBarrierForSpace(heap_->cell_space()); |
| 341 | DeactivateIncrementalWriteBarrierForSpace(heap_->map_space()); |
| 342 | DeactivateIncrementalWriteBarrierForSpace(heap_->code_space()); |
| 343 | DeactivateIncrementalWriteBarrierForSpace(heap_->new_space()); |
| 344 | |
| 345 | LargePage* lop = heap_->lo_space()->first_page(); |
| 346 | while (lop->is_valid()) { |
| 347 | SetOldSpacePageFlags(lop, false, false); |
| 348 | lop = lop->next_page(); |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | |
| 353 | void IncrementalMarking::ActivateIncrementalWriteBarrier(PagedSpace* space) { |
| 354 | PageIterator it(space); |
| 355 | while (it.has_next()) { |
| 356 | Page* p = it.next(); |
| 357 | SetOldSpacePageFlags(p, true, is_compacting_); |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | |
| 362 | void IncrementalMarking::ActivateIncrementalWriteBarrier(NewSpace* space) { |
| 363 | NewSpacePageIterator it(space->ToSpaceStart(), space->ToSpaceEnd()); |
| 364 | while (it.has_next()) { |
| 365 | NewSpacePage* p = it.next(); |
| 366 | SetNewSpacePageFlags(p, true); |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | |
| 371 | void IncrementalMarking::ActivateIncrementalWriteBarrier() { |
| 372 | ActivateIncrementalWriteBarrier(heap_->old_pointer_space()); |
| 373 | ActivateIncrementalWriteBarrier(heap_->old_data_space()); |
| 374 | ActivateIncrementalWriteBarrier(heap_->cell_space()); |
| 375 | ActivateIncrementalWriteBarrier(heap_->map_space()); |
| 376 | ActivateIncrementalWriteBarrier(heap_->code_space()); |
| 377 | ActivateIncrementalWriteBarrier(heap_->new_space()); |
| 378 | |
| 379 | LargePage* lop = heap_->lo_space()->first_page(); |
| 380 | while (lop->is_valid()) { |
| 381 | SetOldSpacePageFlags(lop, true, is_compacting_); |
| 382 | lop = lop->next_page(); |
| 383 | } |
| 384 | } |
| 385 | |
| 386 | |
| 387 | bool IncrementalMarking::WorthActivating() { |
| 388 | #ifndef DEBUG |
| 389 | static const intptr_t kActivationThreshold = 8 * MB; |
| 390 | #else |
| 391 | // TODO(gc) consider setting this to some low level so that some |
| 392 | // debug tests run with incremental marking and some without. |
| 393 | static const intptr_t kActivationThreshold = 0; |
| 394 | #endif |
| 395 | |
| 396 | return !FLAG_expose_gc && |
| 397 | FLAG_incremental_marking && |
| 398 | !Serializer::enabled() && |
| 399 | heap_->PromotedSpaceSize() > kActivationThreshold; |
| 400 | } |
| 401 | |
| 402 | |
| 403 | void IncrementalMarking::ActivateGeneratedStub(Code* stub) { |
| 404 | ASSERT(RecordWriteStub::GetMode(stub) == |
| 405 | RecordWriteStub::STORE_BUFFER_ONLY); |
| 406 | |
| 407 | if (!IsMarking()) { |
| 408 | // Initially stub is generated in STORE_BUFFER_ONLY mode thus |
| 409 | // we don't need to do anything if incremental marking is |
| 410 | // not active. |
| 411 | } else if (IsCompacting()) { |
| 412 | RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL_COMPACTION); |
| 413 | } else { |
| 414 | RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL); |
| 415 | } |
| 416 | } |
| 417 | |
| 418 | |
| 419 | static void PatchIncrementalMarkingRecordWriteStubs( |
| 420 | Heap* heap, RecordWriteStub::Mode mode) { |
| 421 | NumberDictionary* stubs = heap->code_stubs(); |
| 422 | |
| 423 | int capacity = stubs->Capacity(); |
| 424 | for (int i = 0; i < capacity; i++) { |
| 425 | Object* k = stubs->KeyAt(i); |
| 426 | if (stubs->IsKey(k)) { |
| 427 | uint32_t key = NumberToUint32(k); |
| 428 | |
| 429 | if (CodeStub::MajorKeyFromKey(key) == |
| 430 | CodeStub::RecordWrite) { |
| 431 | Object* e = stubs->ValueAt(i); |
| 432 | if (e->IsCode()) { |
| 433 | RecordWriteStub::Patch(Code::cast(e), mode); |
| 434 | } |
| 435 | } |
| 436 | } |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | |
| 441 | void IncrementalMarking::EnsureMarkingDequeIsCommitted() { |
| 442 | if (marking_deque_memory_ == NULL) { |
| 443 | marking_deque_memory_ = new VirtualMemory(4 * MB); |
| 444 | } |
| 445 | if (!marking_deque_memory_committed_) { |
| 446 | bool success = marking_deque_memory_->Commit( |
| 447 | reinterpret_cast<Address>(marking_deque_memory_->address()), |
| 448 | marking_deque_memory_->size(), |
| 449 | false); // Not executable. |
| 450 | CHECK(success); |
| 451 | marking_deque_memory_committed_ = true; |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | void IncrementalMarking::UncommitMarkingDeque() { |
| 456 | if (state_ == STOPPED && marking_deque_memory_committed_) { |
| 457 | bool success = marking_deque_memory_->Uncommit( |
| 458 | reinterpret_cast<Address>(marking_deque_memory_->address()), |
| 459 | marking_deque_memory_->size()); |
| 460 | CHECK(success); |
| 461 | marking_deque_memory_committed_ = false; |
| 462 | } |
| 463 | } |
| 464 | |
| 465 | |
| 466 | void IncrementalMarking::Start() { |
| 467 | if (FLAG_trace_incremental_marking) { |
| 468 | PrintF("[IncrementalMarking] Start\n"); |
| 469 | } |
| 470 | ASSERT(FLAG_incremental_marking); |
| 471 | ASSERT(state_ == STOPPED); |
| 472 | |
| 473 | ResetStepCounters(); |
| 474 | |
| 475 | if (heap_->old_pointer_space()->IsSweepingComplete() && |
| 476 | heap_->old_data_space()->IsSweepingComplete()) { |
| 477 | StartMarking(ALLOW_COMPACTION); |
| 478 | } else { |
| 479 | if (FLAG_trace_incremental_marking) { |
| 480 | PrintF("[IncrementalMarking] Start sweeping.\n"); |
| 481 | } |
| 482 | state_ = SWEEPING; |
| 483 | } |
| 484 | |
| 485 | heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold); |
| 486 | } |
| 487 | |
| 488 | |
| 489 | static void MarkObjectGreyDoNotEnqueue(Object* obj) { |
| 490 | if (obj->IsHeapObject()) { |
| 491 | HeapObject* heap_obj = HeapObject::cast(obj); |
| 492 | MarkBit mark_bit = Marking::MarkBitFrom(HeapObject::cast(obj)); |
| 493 | if (Marking::IsBlack(mark_bit)) { |
| 494 | MemoryChunk::IncrementLiveBytes(heap_obj->address(), |
| 495 | -heap_obj->Size()); |
| 496 | } |
| 497 | Marking::AnyToGrey(mark_bit); |
| 498 | } |
| 499 | } |
| 500 | |
| 501 | |
| 502 | void IncrementalMarking::StartMarking(CompactionFlag flag) { |
| 503 | if (FLAG_trace_incremental_marking) { |
| 504 | PrintF("[IncrementalMarking] Start marking\n"); |
| 505 | } |
| 506 | |
| 507 | is_compacting_ = !FLAG_never_compact && (flag == ALLOW_COMPACTION) && |
| 508 | heap_->mark_compact_collector()->StartCompaction(); |
| 509 | |
| 510 | state_ = MARKING; |
| 511 | |
| 512 | RecordWriteStub::Mode mode = is_compacting_ ? |
| 513 | RecordWriteStub::INCREMENTAL_COMPACTION : RecordWriteStub::INCREMENTAL; |
| 514 | |
| 515 | PatchIncrementalMarkingRecordWriteStubs(heap_, mode); |
| 516 | |
| 517 | EnsureMarkingDequeIsCommitted(); |
| 518 | |
| 519 | // Initialize marking stack. |
| 520 | Address addr = static_cast<Address>(marking_deque_memory_->address()); |
| 521 | size_t size = marking_deque_memory_->size(); |
| 522 | if (FLAG_force_marking_deque_overflows) size = 64 * kPointerSize; |
| 523 | marking_deque_.Initialize(addr, addr + size); |
| 524 | |
| 525 | ActivateIncrementalWriteBarrier(); |
| 526 | |
| 527 | #ifdef DEBUG |
| 528 | // Marking bits are cleared by the sweeper. |
| 529 | if (FLAG_verify_heap) { |
| 530 | heap_->mark_compact_collector()->VerifyMarkbitsAreClean(); |
| 531 | } |
| 532 | #endif |
| 533 | |
| 534 | heap_->CompletelyClearInstanceofCache(); |
| 535 | heap_->isolate()->compilation_cache()->MarkCompactPrologue(); |
| 536 | |
| 537 | if (FLAG_cleanup_code_caches_at_gc) { |
| 538 | // We will mark cache black with a separate pass |
| 539 | // when we finish marking. |
| 540 | MarkObjectGreyDoNotEnqueue(heap_->polymorphic_code_cache()); |
| 541 | } |
| 542 | |
| 543 | // Mark strong roots grey. |
| 544 | IncrementalMarkingRootMarkingVisitor visitor(heap_, this); |
| 545 | heap_->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG); |
| 546 | |
| 547 | // Ready to start incremental marking. |
| 548 | if (FLAG_trace_incremental_marking) { |
| 549 | PrintF("[IncrementalMarking] Running\n"); |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | |
| 554 | void IncrementalMarking::PrepareForScavenge() { |
| 555 | if (!IsMarking()) return; |
| 556 | NewSpacePageIterator it(heap_->new_space()->FromSpaceStart(), |
| 557 | heap_->new_space()->FromSpaceEnd()); |
| 558 | while (it.has_next()) { |
| 559 | Bitmap::Clear(it.next()); |
| 560 | } |
| 561 | } |
| 562 | |
| 563 | |
| 564 | void IncrementalMarking::UpdateMarkingDequeAfterScavenge() { |
| 565 | if (!IsMarking()) return; |
| 566 | |
| 567 | int current = marking_deque_.bottom(); |
| 568 | int mask = marking_deque_.mask(); |
| 569 | int limit = marking_deque_.top(); |
| 570 | HeapObject** array = marking_deque_.array(); |
| 571 | int new_top = current; |
| 572 | |
| 573 | Map* filler_map = heap_->one_pointer_filler_map(); |
| 574 | |
| 575 | while (current != limit) { |
| 576 | HeapObject* obj = array[current]; |
| 577 | ASSERT(obj->IsHeapObject()); |
| 578 | current = ((current + 1) & mask); |
| 579 | if (heap_->InNewSpace(obj)) { |
| 580 | MapWord map_word = obj->map_word(); |
| 581 | if (map_word.IsForwardingAddress()) { |
| 582 | HeapObject* dest = map_word.ToForwardingAddress(); |
| 583 | array[new_top] = dest; |
| 584 | new_top = ((new_top + 1) & mask); |
| 585 | ASSERT(new_top != marking_deque_.bottom()); |
| 586 | #ifdef DEBUG |
| 587 | MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| 588 | ASSERT(Marking::IsGrey(mark_bit) || |
| 589 | (obj->IsFiller() && Marking::IsWhite(mark_bit))); |
| 590 | #endif |
| 591 | } |
| 592 | } else if (obj->map() != filler_map) { |
| 593 | // Skip one word filler objects that appear on the |
| 594 | // stack when we perform in place array shift. |
| 595 | array[new_top] = obj; |
| 596 | new_top = ((new_top + 1) & mask); |
| 597 | ASSERT(new_top != marking_deque_.bottom()); |
| 598 | #ifdef DEBUG |
| 599 | MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| 600 | ASSERT(Marking::IsGrey(mark_bit) || |
| 601 | (obj->IsFiller() && Marking::IsWhite(mark_bit))); |
| 602 | #endif |
| 603 | } |
| 604 | } |
| 605 | marking_deque_.set_top(new_top); |
| 606 | |
| 607 | steps_took_since_last_gc_ = 0; |
| 608 | steps_count_since_last_gc_ = 0; |
| 609 | longest_step_ = 0.0; |
| 610 | } |
| 611 | |
| 612 | |
| 613 | void IncrementalMarking::VisitGlobalContext(Context* ctx, ObjectVisitor* v) { |
| 614 | v->VisitPointers( |
| 615 | HeapObject::RawField( |
| 616 | ctx, Context::MarkCompactBodyDescriptor::kStartOffset), |
| 617 | HeapObject::RawField( |
| 618 | ctx, Context::MarkCompactBodyDescriptor::kEndOffset)); |
| 619 | |
| 620 | MarkCompactCollector* collector = heap_->mark_compact_collector(); |
| 621 | for (int idx = Context::FIRST_WEAK_SLOT; |
| 622 | idx < Context::GLOBAL_CONTEXT_SLOTS; |
| 623 | ++idx) { |
| 624 | Object** slot = |
| 625 | HeapObject::RawField(ctx, FixedArray::OffsetOfElementAt(idx)); |
| 626 | collector->RecordSlot(slot, slot, *slot); |
| 627 | } |
| 628 | } |
| 629 | |
| 630 | |
| 631 | void IncrementalMarking::Hurry() { |
| 632 | if (state() == MARKING) { |
| 633 | double start = 0.0; |
| 634 | if (FLAG_trace_incremental_marking) { |
| 635 | PrintF("[IncrementalMarking] Hurry\n"); |
| 636 | start = OS::TimeCurrentMillis(); |
| 637 | } |
| 638 | // TODO(gc) hurry can mark objects it encounters black as mutator |
| 639 | // was stopped. |
| 640 | Map* filler_map = heap_->one_pointer_filler_map(); |
| 641 | Map* global_context_map = heap_->global_context_map(); |
| 642 | IncrementalMarkingMarkingVisitor marking_visitor(heap_, this); |
| 643 | while (!marking_deque_.IsEmpty()) { |
| 644 | HeapObject* obj = marking_deque_.Pop(); |
| 645 | |
| 646 | // Explicitly skip one word fillers. Incremental markbit patterns are |
| 647 | // correct only for objects that occupy at least two words. |
| 648 | Map* map = obj->map(); |
| 649 | if (map == filler_map) { |
| 650 | continue; |
| 651 | } else if (map == global_context_map) { |
| 652 | // Global contexts have weak fields. |
| 653 | VisitGlobalContext(Context::cast(obj), &marking_visitor); |
| 654 | } else { |
| 655 | obj->Iterate(&marking_visitor); |
| 656 | } |
| 657 | |
| 658 | MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| 659 | ASSERT(!Marking::IsBlack(mark_bit)); |
| 660 | Marking::MarkBlack(mark_bit); |
| 661 | MemoryChunk::IncrementLiveBytes(obj->address(), obj->Size()); |
| 662 | } |
| 663 | state_ = COMPLETE; |
| 664 | if (FLAG_trace_incremental_marking) { |
| 665 | double end = OS::TimeCurrentMillis(); |
| 666 | PrintF("[IncrementalMarking] Complete (hurry), spent %d ms.\n", |
| 667 | static_cast<int>(end - start)); |
| 668 | } |
| 669 | } |
| 670 | |
| 671 | if (FLAG_cleanup_code_caches_at_gc) { |
| 672 | PolymorphicCodeCache* poly_cache = heap_->polymorphic_code_cache(); |
| 673 | Marking::GreyToBlack(Marking::MarkBitFrom(poly_cache)); |
| 674 | MemoryChunk::IncrementLiveBytes(poly_cache->address(), |
| 675 | PolymorphicCodeCache::kSize); |
| 676 | } |
| 677 | |
| 678 | Object* context = heap_->global_contexts_list(); |
| 679 | while (!context->IsUndefined()) { |
| 680 | // GC can happen when the context is not fully initialized, |
| 681 | // so the cache can be undefined. |
| 682 | HeapObject* cache = HeapObject::cast( |
| 683 | Context::cast(context)->get(Context::NORMALIZED_MAP_CACHE_INDEX)); |
| 684 | if (!cache->IsUndefined()) { |
| 685 | MarkBit mark_bit = Marking::MarkBitFrom(cache); |
| 686 | if (Marking::IsGrey(mark_bit)) { |
| 687 | Marking::GreyToBlack(mark_bit); |
| 688 | MemoryChunk::IncrementLiveBytes(cache->address(), cache->Size()); |
| 689 | } |
| 690 | } |
| 691 | context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK); |
| 692 | } |
| 693 | } |
| 694 | |
| 695 | |
| 696 | void IncrementalMarking::Abort() { |
| 697 | if (IsStopped()) return; |
| 698 | if (FLAG_trace_incremental_marking) { |
| 699 | PrintF("[IncrementalMarking] Aborting.\n"); |
| 700 | } |
| 701 | heap_->new_space()->LowerInlineAllocationLimit(0); |
| 702 | IncrementalMarking::set_should_hurry(false); |
| 703 | ResetStepCounters(); |
| 704 | if (IsMarking()) { |
| 705 | PatchIncrementalMarkingRecordWriteStubs(heap_, |
| 706 | RecordWriteStub::STORE_BUFFER_ONLY); |
| 707 | DeactivateIncrementalWriteBarrier(); |
| 708 | |
| 709 | if (is_compacting_) { |
| 710 | LargeObjectIterator it(heap_->lo_space()); |
| 711 | for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) { |
| 712 | Page* p = Page::FromAddress(obj->address()); |
| 713 | if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) { |
| 714 | p->ClearFlag(Page::RESCAN_ON_EVACUATION); |
| 715 | } |
| 716 | } |
| 717 | } |
| 718 | } |
| 719 | heap_->isolate()->stack_guard()->Continue(GC_REQUEST); |
| 720 | state_ = STOPPED; |
| 721 | is_compacting_ = false; |
| 722 | } |
| 723 | |
| 724 | |
| 725 | void IncrementalMarking::Finalize() { |
| 726 | Hurry(); |
| 727 | state_ = STOPPED; |
| 728 | is_compacting_ = false; |
| 729 | heap_->new_space()->LowerInlineAllocationLimit(0); |
| 730 | IncrementalMarking::set_should_hurry(false); |
| 731 | ResetStepCounters(); |
| 732 | PatchIncrementalMarkingRecordWriteStubs(heap_, |
| 733 | RecordWriteStub::STORE_BUFFER_ONLY); |
| 734 | DeactivateIncrementalWriteBarrier(); |
| 735 | ASSERT(marking_deque_.IsEmpty()); |
| 736 | heap_->isolate()->stack_guard()->Continue(GC_REQUEST); |
| 737 | } |
| 738 | |
| 739 | |
| 740 | void IncrementalMarking::MarkingComplete() { |
| 741 | state_ = COMPLETE; |
| 742 | // We will set the stack guard to request a GC now. This will mean the rest |
| 743 | // of the GC gets performed as soon as possible (we can't do a GC here in a |
| 744 | // record-write context). If a few things get allocated between now and then |
| 745 | // that shouldn't make us do a scavenge and keep being incremental, so we set |
| 746 | // the should-hurry flag to indicate that there can't be much work left to do. |
| 747 | set_should_hurry(true); |
| 748 | if (FLAG_trace_incremental_marking) { |
| 749 | PrintF("[IncrementalMarking] Complete (normal).\n"); |
| 750 | } |
| 751 | heap_->isolate()->stack_guard()->RequestGC(); |
| 752 | } |
| 753 | |
| 754 | |
| 755 | void IncrementalMarking::Step(intptr_t allocated_bytes) { |
| 756 | if (heap_->gc_state() != Heap::NOT_IN_GC || |
| 757 | !FLAG_incremental_marking || |
| 758 | !FLAG_incremental_marking_steps || |
| 759 | (state_ != SWEEPING && state_ != MARKING)) { |
| 760 | return; |
| 761 | } |
| 762 | |
| 763 | allocated_ += allocated_bytes; |
| 764 | |
| 765 | if (allocated_ < kAllocatedThreshold) return; |
| 766 | |
| 767 | if (state_ == MARKING && no_marking_scope_depth_ > 0) return; |
| 768 | |
| 769 | intptr_t bytes_to_process = allocated_ * allocation_marking_factor_; |
| 770 | bytes_scanned_ += bytes_to_process; |
| 771 | |
| 772 | double start = 0; |
| 773 | |
| 774 | if (FLAG_trace_incremental_marking || FLAG_trace_gc) { |
| 775 | start = OS::TimeCurrentMillis(); |
| 776 | } |
| 777 | |
| 778 | if (state_ == SWEEPING) { |
| 779 | if (heap_->old_pointer_space()->AdvanceSweeper(bytes_to_process) && |
| 780 | heap_->old_data_space()->AdvanceSweeper(bytes_to_process)) { |
| 781 | bytes_scanned_ = 0; |
| 782 | StartMarking(PREVENT_COMPACTION); |
| 783 | } |
| 784 | } else if (state_ == MARKING) { |
| 785 | Map* filler_map = heap_->one_pointer_filler_map(); |
| 786 | Map* global_context_map = heap_->global_context_map(); |
| 787 | IncrementalMarkingMarkingVisitor marking_visitor(heap_, this); |
| 788 | while (!marking_deque_.IsEmpty() && bytes_to_process > 0) { |
| 789 | HeapObject* obj = marking_deque_.Pop(); |
| 790 | |
| 791 | // Explicitly skip one word fillers. Incremental markbit patterns are |
| 792 | // correct only for objects that occupy at least two words. |
| 793 | Map* map = obj->map(); |
| 794 | if (map == filler_map) continue; |
| 795 | |
| 796 | int size = obj->SizeFromMap(map); |
| 797 | bytes_to_process -= size; |
| 798 | MarkBit map_mark_bit = Marking::MarkBitFrom(map); |
| 799 | if (Marking::IsWhite(map_mark_bit)) { |
| 800 | WhiteToGreyAndPush(map, map_mark_bit); |
| 801 | } |
| 802 | |
| 803 | // TODO(gc) switch to static visitor instead of normal visitor. |
| 804 | if (map == global_context_map) { |
| 805 | // Global contexts have weak fields. |
| 806 | Context* ctx = Context::cast(obj); |
| 807 | |
| 808 | // We will mark cache black with a separate pass |
| 809 | // when we finish marking. |
| 810 | MarkObjectGreyDoNotEnqueue(ctx->normalized_map_cache()); |
| 811 | |
| 812 | VisitGlobalContext(ctx, &marking_visitor); |
| 813 | } else { |
| 814 | obj->IterateBody(map->instance_type(), size, &marking_visitor); |
| 815 | } |
| 816 | |
| 817 | MarkBit obj_mark_bit = Marking::MarkBitFrom(obj); |
| 818 | SLOW_ASSERT(Marking::IsGrey(obj_mark_bit) || |
| 819 | (obj->IsFiller() && Marking::IsWhite(obj_mark_bit))); |
| 820 | Marking::MarkBlack(obj_mark_bit); |
| 821 | MemoryChunk::IncrementLiveBytes(obj->address(), size); |
| 822 | } |
| 823 | if (marking_deque_.IsEmpty()) MarkingComplete(); |
| 824 | } |
| 825 | |
| 826 | allocated_ = 0; |
| 827 | |
| 828 | steps_count_++; |
| 829 | steps_count_since_last_gc_++; |
| 830 | |
| 831 | bool speed_up = false; |
| 832 | |
| 833 | if ((steps_count_ % kAllocationMarkingFactorSpeedupInterval) == 0) { |
| 834 | if (FLAG_trace_gc) { |
| 835 | PrintF("Speed up marking after %d steps\n", |
| 836 | static_cast<int>(kAllocationMarkingFactorSpeedupInterval)); |
| 837 | } |
| 838 | speed_up = true; |
| 839 | } |
| 840 | |
| 841 | bool space_left_is_very_small = |
| 842 | (old_generation_space_available_at_start_of_incremental_ < 10 * MB); |
| 843 | |
| 844 | bool only_1_nth_of_space_that_was_available_still_left = |
| 845 | (SpaceLeftInOldSpace() * (allocation_marking_factor_ + 1) < |
| 846 | old_generation_space_available_at_start_of_incremental_); |
| 847 | |
| 848 | if (space_left_is_very_small || |
| 849 | only_1_nth_of_space_that_was_available_still_left) { |
| 850 | if (FLAG_trace_gc) PrintF("Speed up marking because of low space left\n"); |
| 851 | speed_up = true; |
| 852 | } |
| 853 | |
| 854 | bool size_of_old_space_multiplied_by_n_during_marking = |
| 855 | (heap_->PromotedTotalSize() > |
| 856 | (allocation_marking_factor_ + 1) * |
| 857 | old_generation_space_used_at_start_of_incremental_); |
| 858 | if (size_of_old_space_multiplied_by_n_during_marking) { |
| 859 | speed_up = true; |
| 860 | if (FLAG_trace_gc) { |
| 861 | PrintF("Speed up marking because of heap size increase\n"); |
| 862 | } |
| 863 | } |
| 864 | |
| 865 | int64_t promoted_during_marking = heap_->PromotedTotalSize() |
| 866 | - old_generation_space_used_at_start_of_incremental_; |
| 867 | intptr_t delay = allocation_marking_factor_ * MB; |
| 868 | intptr_t scavenge_slack = heap_->MaxSemiSpaceSize(); |
| 869 | |
| 870 | // We try to scan at at least twice the speed that we are allocating. |
| 871 | if (promoted_during_marking > bytes_scanned_ / 2 + scavenge_slack + delay) { |
| 872 | if (FLAG_trace_gc) { |
| 873 | PrintF("Speed up marking because marker was not keeping up\n"); |
| 874 | } |
| 875 | speed_up = true; |
| 876 | } |
| 877 | |
| 878 | if (speed_up) { |
| 879 | if (state_ != MARKING) { |
| 880 | if (FLAG_trace_gc) { |
| 881 | PrintF("Postponing speeding up marking until marking starts\n"); |
| 882 | } |
| 883 | } else { |
| 884 | allocation_marking_factor_ += kAllocationMarkingFactorSpeedup; |
| 885 | allocation_marking_factor_ = static_cast<int>( |
| 886 | Min(kMaxAllocationMarkingFactor, |
| 887 | static_cast<intptr_t>(allocation_marking_factor_ * 1.3))); |
| 888 | if (FLAG_trace_gc) { |
| 889 | PrintF("Marking speed increased to %d\n", allocation_marking_factor_); |
| 890 | } |
| 891 | } |
| 892 | } |
| 893 | |
| 894 | if (FLAG_trace_incremental_marking || FLAG_trace_gc) { |
| 895 | double end = OS::TimeCurrentMillis(); |
| 896 | double delta = (end - start); |
| 897 | longest_step_ = Max(longest_step_, delta); |
| 898 | steps_took_ += delta; |
| 899 | steps_took_since_last_gc_ += delta; |
| 900 | } |
| 901 | } |
| 902 | |
| 903 | |
| 904 | void IncrementalMarking::ResetStepCounters() { |
| 905 | steps_count_ = 0; |
| 906 | steps_took_ = 0; |
| 907 | longest_step_ = 0.0; |
| 908 | old_generation_space_available_at_start_of_incremental_ = |
| 909 | SpaceLeftInOldSpace(); |
| 910 | old_generation_space_used_at_start_of_incremental_ = |
| 911 | heap_->PromotedTotalSize(); |
| 912 | steps_count_since_last_gc_ = 0; |
| 913 | steps_took_since_last_gc_ = 0; |
| 914 | bytes_rescanned_ = 0; |
| 915 | allocation_marking_factor_ = kInitialAllocationMarkingFactor; |
| 916 | bytes_scanned_ = 0; |
| 917 | } |
| 918 | |
| 919 | |
| 920 | int64_t IncrementalMarking::SpaceLeftInOldSpace() { |
| 921 | return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSize(); |
| 922 | } |
| 923 | |
| 924 | } } // namespace v8::internal |