Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2012 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 5 | #include "src/heap/mark-compact.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 6 | |
| 7 | #include "src/base/atomicops.h" |
| 8 | #include "src/base/bits.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 9 | #include "src/base/sys-info.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 10 | #include "src/code-stubs.h" |
| 11 | #include "src/compilation-cache.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 12 | #include "src/deoptimizer.h" |
| 13 | #include "src/execution.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 14 | #include "src/frames-inl.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 15 | #include "src/gdb-jit.h" |
| 16 | #include "src/global-handles.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 17 | #include "src/heap/array-buffer-tracker.h" |
| 18 | #include "src/heap/gc-tracer.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 19 | #include "src/heap/incremental-marking.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 20 | #include "src/heap/mark-compact-inl.h" |
| 21 | #include "src/heap/object-stats.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 22 | #include "src/heap/objects-visiting.h" |
| 23 | #include "src/heap/objects-visiting-inl.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 24 | #include "src/heap/slots-buffer.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 25 | #include "src/heap/spaces-inl.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 26 | #include "src/ic/ic.h" |
| 27 | #include "src/ic/stub-cache.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 28 | #include "src/profiler/cpu-profiler.h" |
| 29 | #include "src/v8.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 30 | |
| 31 | namespace v8 { |
| 32 | namespace internal { |
| 33 | |
| 34 | |
| 35 | const char* Marking::kWhiteBitPattern = "00"; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 36 | const char* Marking::kBlackBitPattern = "11"; |
| 37 | const char* Marking::kGreyBitPattern = "10"; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 38 | const char* Marking::kImpossibleBitPattern = "01"; |
| 39 | |
| 40 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 41 | // The following has to hold in order for {Marking::MarkBitFrom} to not produce |
| 42 | // invalid {kImpossibleBitPattern} in the marking bitmap by overlapping. |
| 43 | STATIC_ASSERT(Heap::kMinObjectSizeInWords >= 2); |
| 44 | |
| 45 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 46 | // ------------------------------------------------------------------------- |
| 47 | // MarkCompactCollector |
| 48 | |
| 49 | MarkCompactCollector::MarkCompactCollector(Heap* heap) |
| 50 | : // NOLINT |
| 51 | #ifdef DEBUG |
| 52 | state_(IDLE), |
| 53 | #endif |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 54 | marking_parity_(ODD_MARKING_PARITY), |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 55 | was_marked_incrementally_(false), |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 56 | evacuation_(false), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 57 | slots_buffer_allocator_(nullptr), |
| 58 | migration_slots_buffer_(nullptr), |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 59 | heap_(heap), |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 60 | marking_deque_memory_(NULL), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 61 | marking_deque_memory_committed_(0), |
| 62 | code_flusher_(nullptr), |
| 63 | have_code_to_deoptimize_(false), |
| 64 | compacting_(false), |
| 65 | sweeping_in_progress_(false), |
| 66 | compaction_in_progress_(false), |
| 67 | pending_sweeper_tasks_semaphore_(0), |
| 68 | pending_compaction_tasks_semaphore_(0) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 69 | } |
| 70 | |
| 71 | #ifdef VERIFY_HEAP |
| 72 | class VerifyMarkingVisitor : public ObjectVisitor { |
| 73 | public: |
| 74 | explicit VerifyMarkingVisitor(Heap* heap) : heap_(heap) {} |
| 75 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 76 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 77 | for (Object** current = start; current < end; current++) { |
| 78 | if ((*current)->IsHeapObject()) { |
| 79 | HeapObject* object = HeapObject::cast(*current); |
| 80 | CHECK(heap_->mark_compact_collector()->IsMarked(object)); |
| 81 | } |
| 82 | } |
| 83 | } |
| 84 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 85 | void VisitEmbeddedPointer(RelocInfo* rinfo) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 86 | DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT); |
| 87 | if (!rinfo->host()->IsWeakObject(rinfo->target_object())) { |
| 88 | Object* p = rinfo->target_object(); |
| 89 | VisitPointer(&p); |
| 90 | } |
| 91 | } |
| 92 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 93 | void VisitCell(RelocInfo* rinfo) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 94 | Code* code = rinfo->host(); |
| 95 | DCHECK(rinfo->rmode() == RelocInfo::CELL); |
| 96 | if (!code->IsWeakObject(rinfo->target_cell())) { |
| 97 | ObjectVisitor::VisitCell(rinfo); |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | private: |
| 102 | Heap* heap_; |
| 103 | }; |
| 104 | |
| 105 | |
| 106 | static void VerifyMarking(Heap* heap, Address bottom, Address top) { |
| 107 | VerifyMarkingVisitor visitor(heap); |
| 108 | HeapObject* object; |
| 109 | Address next_object_must_be_here_or_later = bottom; |
| 110 | |
| 111 | for (Address current = bottom; current < top; current += kPointerSize) { |
| 112 | object = HeapObject::FromAddress(current); |
| 113 | if (MarkCompactCollector::IsMarked(object)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 114 | CHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 115 | CHECK(current >= next_object_must_be_here_or_later); |
| 116 | object->Iterate(&visitor); |
| 117 | next_object_must_be_here_or_later = current + object->Size(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 118 | // The next word for sure belongs to the current object, jump over it. |
| 119 | current += kPointerSize; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | |
| 125 | static void VerifyMarking(NewSpace* space) { |
| 126 | Address end = space->top(); |
| 127 | NewSpacePageIterator it(space->bottom(), end); |
| 128 | // The bottom position is at the start of its page. Allows us to use |
| 129 | // page->area_start() as start of range on all pages. |
| 130 | CHECK_EQ(space->bottom(), |
| 131 | NewSpacePage::FromAddress(space->bottom())->area_start()); |
| 132 | while (it.has_next()) { |
| 133 | NewSpacePage* page = it.next(); |
| 134 | Address limit = it.has_next() ? page->area_end() : end; |
| 135 | CHECK(limit == end || !page->Contains(end)); |
| 136 | VerifyMarking(space->heap(), page->area_start(), limit); |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | |
| 141 | static void VerifyMarking(PagedSpace* space) { |
| 142 | PageIterator it(space); |
| 143 | |
| 144 | while (it.has_next()) { |
| 145 | Page* p = it.next(); |
| 146 | VerifyMarking(space->heap(), p->area_start(), p->area_end()); |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | |
| 151 | static void VerifyMarking(Heap* heap) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 152 | VerifyMarking(heap->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 153 | VerifyMarking(heap->code_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 154 | VerifyMarking(heap->map_space()); |
| 155 | VerifyMarking(heap->new_space()); |
| 156 | |
| 157 | VerifyMarkingVisitor visitor(heap); |
| 158 | |
| 159 | LargeObjectIterator it(heap->lo_space()); |
| 160 | for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) { |
| 161 | if (MarkCompactCollector::IsMarked(obj)) { |
| 162 | obj->Iterate(&visitor); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | heap->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG); |
| 167 | } |
| 168 | |
| 169 | |
| 170 | class VerifyEvacuationVisitor : public ObjectVisitor { |
| 171 | public: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 172 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 173 | for (Object** current = start; current < end; current++) { |
| 174 | if ((*current)->IsHeapObject()) { |
| 175 | HeapObject* object = HeapObject::cast(*current); |
| 176 | CHECK(!MarkCompactCollector::IsOnEvacuationCandidate(object)); |
| 177 | } |
| 178 | } |
| 179 | } |
| 180 | }; |
| 181 | |
| 182 | |
| 183 | static void VerifyEvacuation(Page* page) { |
| 184 | VerifyEvacuationVisitor visitor; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 185 | HeapObjectIterator iterator(page); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 186 | for (HeapObject* heap_object = iterator.Next(); heap_object != NULL; |
| 187 | heap_object = iterator.Next()) { |
| 188 | // We skip free space objects. |
| 189 | if (!heap_object->IsFiller()) { |
| 190 | heap_object->Iterate(&visitor); |
| 191 | } |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | |
| 196 | static void VerifyEvacuation(NewSpace* space) { |
| 197 | NewSpacePageIterator it(space->bottom(), space->top()); |
| 198 | VerifyEvacuationVisitor visitor; |
| 199 | |
| 200 | while (it.has_next()) { |
| 201 | NewSpacePage* page = it.next(); |
| 202 | Address current = page->area_start(); |
| 203 | Address limit = it.has_next() ? page->area_end() : space->top(); |
| 204 | CHECK(limit == space->top() || !page->Contains(space->top())); |
| 205 | while (current < limit) { |
| 206 | HeapObject* object = HeapObject::FromAddress(current); |
| 207 | object->Iterate(&visitor); |
| 208 | current += object->Size(); |
| 209 | } |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | |
| 214 | static void VerifyEvacuation(Heap* heap, PagedSpace* space) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 215 | if (FLAG_use_allocation_folding && (space == heap->old_space())) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 216 | return; |
| 217 | } |
| 218 | PageIterator it(space); |
| 219 | |
| 220 | while (it.has_next()) { |
| 221 | Page* p = it.next(); |
| 222 | if (p->IsEvacuationCandidate()) continue; |
| 223 | VerifyEvacuation(p); |
| 224 | } |
| 225 | } |
| 226 | |
| 227 | |
| 228 | static void VerifyEvacuation(Heap* heap) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 229 | VerifyEvacuation(heap, heap->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 230 | VerifyEvacuation(heap, heap->code_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 231 | VerifyEvacuation(heap, heap->map_space()); |
| 232 | VerifyEvacuation(heap->new_space()); |
| 233 | |
| 234 | VerifyEvacuationVisitor visitor; |
| 235 | heap->IterateStrongRoots(&visitor, VISIT_ALL); |
| 236 | } |
| 237 | #endif // VERIFY_HEAP |
| 238 | |
| 239 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 240 | void MarkCompactCollector::SetUp() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 241 | DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0); |
| 242 | DCHECK(strcmp(Marking::kBlackBitPattern, "11") == 0); |
| 243 | DCHECK(strcmp(Marking::kGreyBitPattern, "10") == 0); |
| 244 | DCHECK(strcmp(Marking::kImpossibleBitPattern, "01") == 0); |
| 245 | |
| 246 | free_list_old_space_.Reset(new FreeList(heap_->old_space())); |
| 247 | free_list_code_space_.Reset(new FreeList(heap_->code_space())); |
| 248 | free_list_map_space_.Reset(new FreeList(heap_->map_space())); |
| 249 | EnsureMarkingDequeIsReserved(); |
| 250 | EnsureMarkingDequeIsCommitted(kMinMarkingDequeSize); |
| 251 | slots_buffer_allocator_ = new SlotsBufferAllocator(); |
| 252 | |
| 253 | if (FLAG_flush_code) { |
| 254 | code_flusher_ = new CodeFlusher(isolate()); |
| 255 | if (FLAG_trace_code_flushing) { |
| 256 | PrintF("[code-flushing is now on]\n"); |
| 257 | } |
| 258 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 259 | } |
| 260 | |
| 261 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 262 | void MarkCompactCollector::TearDown() { |
| 263 | AbortCompaction(); |
| 264 | delete marking_deque_memory_; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 265 | delete slots_buffer_allocator_; |
| 266 | delete code_flusher_; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 267 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 268 | |
| 269 | |
| 270 | void MarkCompactCollector::AddEvacuationCandidate(Page* p) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 271 | DCHECK(!p->NeverEvacuate()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 272 | p->MarkEvacuationCandidate(); |
| 273 | evacuation_candidates_.Add(p); |
| 274 | } |
| 275 | |
| 276 | |
| 277 | static void TraceFragmentation(PagedSpace* space) { |
| 278 | int number_of_pages = space->CountTotalPages(); |
| 279 | intptr_t reserved = (number_of_pages * space->AreaSize()); |
| 280 | intptr_t free = reserved - space->SizeOfObjects(); |
| 281 | PrintF("[%s]: %d pages, %d (%.1f%%) free\n", |
| 282 | AllocationSpaceName(space->identity()), number_of_pages, |
| 283 | static_cast<int>(free), static_cast<double>(free) * 100 / reserved); |
| 284 | } |
| 285 | |
| 286 | |
| 287 | bool MarkCompactCollector::StartCompaction(CompactionMode mode) { |
| 288 | if (!compacting_) { |
| 289 | DCHECK(evacuation_candidates_.length() == 0); |
| 290 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 291 | CollectEvacuationCandidates(heap()->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 292 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 293 | if (FLAG_compact_code_space) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 294 | CollectEvacuationCandidates(heap()->code_space()); |
| 295 | } else if (FLAG_trace_fragmentation) { |
| 296 | TraceFragmentation(heap()->code_space()); |
| 297 | } |
| 298 | |
| 299 | if (FLAG_trace_fragmentation) { |
| 300 | TraceFragmentation(heap()->map_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 301 | } |
| 302 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 303 | heap()->old_space()->EvictEvacuationCandidatesFromLinearAllocationArea(); |
| 304 | heap()->code_space()->EvictEvacuationCandidatesFromLinearAllocationArea(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 305 | |
| 306 | compacting_ = evacuation_candidates_.length() > 0; |
| 307 | } |
| 308 | |
| 309 | return compacting_; |
| 310 | } |
| 311 | |
| 312 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 313 | void MarkCompactCollector::ClearInvalidStoreAndSlotsBufferEntries() { |
| 314 | { |
| 315 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 316 | GCTracer::Scope::MC_CLEAR_STORE_BUFFER); |
| 317 | heap_->store_buffer()->ClearInvalidStoreBufferEntries(); |
| 318 | } |
| 319 | |
| 320 | { |
| 321 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 322 | GCTracer::Scope::MC_CLEAR_SLOTS_BUFFER); |
| 323 | int number_of_pages = evacuation_candidates_.length(); |
| 324 | for (int i = 0; i < number_of_pages; i++) { |
| 325 | Page* p = evacuation_candidates_[i]; |
| 326 | SlotsBuffer::RemoveInvalidSlots(heap_, p->slots_buffer()); |
| 327 | } |
| 328 | } |
| 329 | #ifdef VERIFY_HEAP |
| 330 | if (FLAG_verify_heap) { |
| 331 | VerifyValidStoreAndSlotsBufferEntries(); |
| 332 | } |
| 333 | #endif |
| 334 | } |
| 335 | |
| 336 | |
| 337 | #ifdef VERIFY_HEAP |
| 338 | static void VerifyValidSlotsBufferEntries(Heap* heap, PagedSpace* space) { |
| 339 | PageIterator it(space); |
| 340 | while (it.has_next()) { |
| 341 | Page* p = it.next(); |
| 342 | SlotsBuffer::VerifySlots(heap, p->slots_buffer()); |
| 343 | } |
| 344 | } |
| 345 | |
| 346 | |
| 347 | void MarkCompactCollector::VerifyValidStoreAndSlotsBufferEntries() { |
| 348 | heap()->store_buffer()->VerifyValidStoreBufferEntries(); |
| 349 | |
| 350 | VerifyValidSlotsBufferEntries(heap(), heap()->old_space()); |
| 351 | VerifyValidSlotsBufferEntries(heap(), heap()->code_space()); |
| 352 | VerifyValidSlotsBufferEntries(heap(), heap()->map_space()); |
| 353 | |
| 354 | LargeObjectIterator it(heap()->lo_space()); |
| 355 | for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) { |
| 356 | MemoryChunk* chunk = MemoryChunk::FromAddress(object->address()); |
| 357 | SlotsBuffer::VerifySlots(heap(), chunk->slots_buffer()); |
| 358 | } |
| 359 | } |
| 360 | #endif |
| 361 | |
| 362 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 363 | void MarkCompactCollector::CollectGarbage() { |
| 364 | // Make sure that Prepare() has been called. The individual steps below will |
| 365 | // update the state as they proceed. |
| 366 | DCHECK(state_ == PREPARE_GC); |
| 367 | |
| 368 | MarkLiveObjects(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 369 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 370 | DCHECK(heap_->incremental_marking()->IsStopped()); |
| 371 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 372 | ClearNonLiveReferences(); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 373 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 374 | #ifdef VERIFY_HEAP |
| 375 | if (FLAG_verify_heap) { |
| 376 | VerifyMarking(heap_); |
| 377 | } |
| 378 | #endif |
| 379 | |
| 380 | SweepSpaces(); |
| 381 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 382 | EvacuateNewSpaceAndCandidates(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 383 | |
| 384 | Finish(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 385 | } |
| 386 | |
| 387 | |
| 388 | #ifdef VERIFY_HEAP |
| 389 | void MarkCompactCollector::VerifyMarkbitsAreClean(PagedSpace* space) { |
| 390 | PageIterator it(space); |
| 391 | |
| 392 | while (it.has_next()) { |
| 393 | Page* p = it.next(); |
| 394 | CHECK(p->markbits()->IsClean()); |
| 395 | CHECK_EQ(0, p->LiveBytes()); |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | |
| 400 | void MarkCompactCollector::VerifyMarkbitsAreClean(NewSpace* space) { |
| 401 | NewSpacePageIterator it(space->bottom(), space->top()); |
| 402 | |
| 403 | while (it.has_next()) { |
| 404 | NewSpacePage* p = it.next(); |
| 405 | CHECK(p->markbits()->IsClean()); |
| 406 | CHECK_EQ(0, p->LiveBytes()); |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | |
| 411 | void MarkCompactCollector::VerifyMarkbitsAreClean() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 412 | VerifyMarkbitsAreClean(heap_->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 413 | VerifyMarkbitsAreClean(heap_->code_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 414 | VerifyMarkbitsAreClean(heap_->map_space()); |
| 415 | VerifyMarkbitsAreClean(heap_->new_space()); |
| 416 | |
| 417 | LargeObjectIterator it(heap_->lo_space()); |
| 418 | for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) { |
| 419 | MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| 420 | CHECK(Marking::IsWhite(mark_bit)); |
| 421 | CHECK_EQ(0, Page::FromAddress(obj->address())->LiveBytes()); |
| 422 | } |
| 423 | } |
| 424 | |
| 425 | |
| 426 | void MarkCompactCollector::VerifyWeakEmbeddedObjectsInCode() { |
| 427 | HeapObjectIterator code_iterator(heap()->code_space()); |
| 428 | for (HeapObject* obj = code_iterator.Next(); obj != NULL; |
| 429 | obj = code_iterator.Next()) { |
| 430 | Code* code = Code::cast(obj); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 431 | if (!code->is_optimized_code()) continue; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 432 | if (WillBeDeoptimized(code)) continue; |
| 433 | code->VerifyEmbeddedObjectsDependency(); |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | |
| 438 | void MarkCompactCollector::VerifyOmittedMapChecks() { |
| 439 | HeapObjectIterator iterator(heap()->map_space()); |
| 440 | for (HeapObject* obj = iterator.Next(); obj != NULL; obj = iterator.Next()) { |
| 441 | Map* map = Map::cast(obj); |
| 442 | map->VerifyOmittedMapChecks(); |
| 443 | } |
| 444 | } |
| 445 | #endif // VERIFY_HEAP |
| 446 | |
| 447 | |
| 448 | static void ClearMarkbitsInPagedSpace(PagedSpace* space) { |
| 449 | PageIterator it(space); |
| 450 | |
| 451 | while (it.has_next()) { |
| 452 | Bitmap::Clear(it.next()); |
| 453 | } |
| 454 | } |
| 455 | |
| 456 | |
| 457 | static void ClearMarkbitsInNewSpace(NewSpace* space) { |
| 458 | NewSpacePageIterator it(space->ToSpaceStart(), space->ToSpaceEnd()); |
| 459 | |
| 460 | while (it.has_next()) { |
| 461 | Bitmap::Clear(it.next()); |
| 462 | } |
| 463 | } |
| 464 | |
| 465 | |
| 466 | void MarkCompactCollector::ClearMarkbits() { |
| 467 | ClearMarkbitsInPagedSpace(heap_->code_space()); |
| 468 | ClearMarkbitsInPagedSpace(heap_->map_space()); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 469 | ClearMarkbitsInPagedSpace(heap_->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 470 | ClearMarkbitsInNewSpace(heap_->new_space()); |
| 471 | |
| 472 | LargeObjectIterator it(heap_->lo_space()); |
| 473 | for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 474 | Marking::MarkWhite(Marking::MarkBitFrom(obj)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 475 | Page::FromAddress(obj->address())->ResetProgressBar(); |
| 476 | Page::FromAddress(obj->address())->ResetLiveBytes(); |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 481 | class MarkCompactCollector::CompactionTask : public CancelableTask { |
| 482 | public: |
| 483 | explicit CompactionTask(Heap* heap, CompactionSpaceCollection* spaces) |
| 484 | : CancelableTask(heap->isolate()), spaces_(spaces) {} |
| 485 | |
| 486 | virtual ~CompactionTask() {} |
| 487 | |
| 488 | private: |
| 489 | // v8::internal::CancelableTask overrides. |
| 490 | void RunInternal() override { |
| 491 | MarkCompactCollector* mark_compact = |
| 492 | isolate()->heap()->mark_compact_collector(); |
| 493 | SlotsBuffer* evacuation_slots_buffer = nullptr; |
| 494 | mark_compact->EvacuatePages(spaces_, &evacuation_slots_buffer); |
| 495 | mark_compact->AddEvacuationSlotsBufferSynchronized(evacuation_slots_buffer); |
| 496 | mark_compact->pending_compaction_tasks_semaphore_.Signal(); |
| 497 | } |
| 498 | |
| 499 | CompactionSpaceCollection* spaces_; |
| 500 | |
| 501 | DISALLOW_COPY_AND_ASSIGN(CompactionTask); |
| 502 | }; |
| 503 | |
| 504 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 505 | class MarkCompactCollector::SweeperTask : public v8::Task { |
| 506 | public: |
| 507 | SweeperTask(Heap* heap, PagedSpace* space) : heap_(heap), space_(space) {} |
| 508 | |
| 509 | virtual ~SweeperTask() {} |
| 510 | |
| 511 | private: |
| 512 | // v8::Task overrides. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 513 | void Run() override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 514 | heap_->mark_compact_collector()->SweepInParallel(space_, 0); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 515 | heap_->mark_compact_collector()->pending_sweeper_tasks_semaphore_.Signal(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 516 | } |
| 517 | |
| 518 | Heap* heap_; |
| 519 | PagedSpace* space_; |
| 520 | |
| 521 | DISALLOW_COPY_AND_ASSIGN(SweeperTask); |
| 522 | }; |
| 523 | |
| 524 | |
| 525 | void MarkCompactCollector::StartSweeperThreads() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 526 | DCHECK(free_list_old_space_.get()->IsEmpty()); |
| 527 | DCHECK(free_list_code_space_.get()->IsEmpty()); |
| 528 | DCHECK(free_list_map_space_.get()->IsEmpty()); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 529 | V8::GetCurrentPlatform()->CallOnBackgroundThread( |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 530 | new SweeperTask(heap(), heap()->old_space()), |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 531 | v8::Platform::kShortRunningTask); |
| 532 | V8::GetCurrentPlatform()->CallOnBackgroundThread( |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 533 | new SweeperTask(heap(), heap()->code_space()), |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 534 | v8::Platform::kShortRunningTask); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 535 | V8::GetCurrentPlatform()->CallOnBackgroundThread( |
| 536 | new SweeperTask(heap(), heap()->map_space()), |
| 537 | v8::Platform::kShortRunningTask); |
| 538 | } |
| 539 | |
| 540 | |
| 541 | void MarkCompactCollector::SweepOrWaitUntilSweepingCompleted(Page* page) { |
| 542 | PagedSpace* owner = reinterpret_cast<PagedSpace*>(page->owner()); |
| 543 | if (!page->SweepingCompleted()) { |
| 544 | SweepInParallel(page, owner); |
| 545 | if (!page->SweepingCompleted()) { |
| 546 | // We were not able to sweep that page, i.e., a concurrent |
| 547 | // sweeper thread currently owns this page. Wait for the sweeper |
| 548 | // thread to be done with this page. |
| 549 | page->WaitUntilSweepingCompleted(); |
| 550 | } |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | |
| 555 | void MarkCompactCollector::SweepAndRefill(CompactionSpace* space) { |
| 556 | if (FLAG_concurrent_sweeping && !IsSweepingCompleted()) { |
| 557 | SweepInParallel(heap()->paged_space(space->identity()), 0); |
| 558 | space->RefillFreeList(); |
| 559 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 560 | } |
| 561 | |
| 562 | |
| 563 | void MarkCompactCollector::EnsureSweepingCompleted() { |
| 564 | DCHECK(sweeping_in_progress_ == true); |
| 565 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 566 | // If sweeping is not completed or not running at all, we try to complete it |
| 567 | // here. |
| 568 | if (!FLAG_concurrent_sweeping || !IsSweepingCompleted()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 569 | SweepInParallel(heap()->paged_space(OLD_SPACE), 0); |
| 570 | SweepInParallel(heap()->paged_space(CODE_SPACE), 0); |
| 571 | SweepInParallel(heap()->paged_space(MAP_SPACE), 0); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 572 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 573 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 574 | if (FLAG_concurrent_sweeping) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 575 | pending_sweeper_tasks_semaphore_.Wait(); |
| 576 | pending_sweeper_tasks_semaphore_.Wait(); |
| 577 | pending_sweeper_tasks_semaphore_.Wait(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 578 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 579 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 580 | ParallelSweepSpacesComplete(); |
| 581 | sweeping_in_progress_ = false; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 582 | heap()->old_space()->RefillFreeList(); |
| 583 | heap()->code_space()->RefillFreeList(); |
| 584 | heap()->map_space()->RefillFreeList(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 585 | |
| 586 | #ifdef VERIFY_HEAP |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 587 | if (FLAG_verify_heap && !evacuation()) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 588 | VerifyEvacuation(heap_); |
| 589 | } |
| 590 | #endif |
| 591 | } |
| 592 | |
| 593 | |
| 594 | bool MarkCompactCollector::IsSweepingCompleted() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 595 | if (!pending_sweeper_tasks_semaphore_.WaitFor( |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 596 | base::TimeDelta::FromSeconds(0))) { |
| 597 | return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 598 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 599 | pending_sweeper_tasks_semaphore_.Signal(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 600 | return true; |
| 601 | } |
| 602 | |
| 603 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 604 | void Marking::TransferMark(Heap* heap, Address old_start, Address new_start) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 605 | // This is only used when resizing an object. |
| 606 | DCHECK(MemoryChunk::FromAddress(old_start) == |
| 607 | MemoryChunk::FromAddress(new_start)); |
| 608 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 609 | if (!heap->incremental_marking()->IsMarking()) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 610 | |
| 611 | // If the mark doesn't move, we don't check the color of the object. |
| 612 | // It doesn't matter whether the object is black, since it hasn't changed |
| 613 | // size, so the adjustment to the live data count will be zero anyway. |
| 614 | if (old_start == new_start) return; |
| 615 | |
| 616 | MarkBit new_mark_bit = MarkBitFrom(new_start); |
| 617 | MarkBit old_mark_bit = MarkBitFrom(old_start); |
| 618 | |
| 619 | #ifdef DEBUG |
| 620 | ObjectColor old_color = Color(old_mark_bit); |
| 621 | #endif |
| 622 | |
| 623 | if (Marking::IsBlack(old_mark_bit)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 624 | Marking::BlackToWhite(old_mark_bit); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 625 | Marking::MarkBlack(new_mark_bit); |
| 626 | return; |
| 627 | } else if (Marking::IsGrey(old_mark_bit)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 628 | Marking::GreyToWhite(old_mark_bit); |
| 629 | heap->incremental_marking()->WhiteToGreyAndPush( |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 630 | HeapObject::FromAddress(new_start), new_mark_bit); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 631 | heap->incremental_marking()->RestartIfNotMarking(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 632 | } |
| 633 | |
| 634 | #ifdef DEBUG |
| 635 | ObjectColor new_color = Color(new_mark_bit); |
| 636 | DCHECK(new_color == old_color); |
| 637 | #endif |
| 638 | } |
| 639 | |
| 640 | |
| 641 | const char* AllocationSpaceName(AllocationSpace space) { |
| 642 | switch (space) { |
| 643 | case NEW_SPACE: |
| 644 | return "NEW_SPACE"; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 645 | case OLD_SPACE: |
| 646 | return "OLD_SPACE"; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 647 | case CODE_SPACE: |
| 648 | return "CODE_SPACE"; |
| 649 | case MAP_SPACE: |
| 650 | return "MAP_SPACE"; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 651 | case LO_SPACE: |
| 652 | return "LO_SPACE"; |
| 653 | default: |
| 654 | UNREACHABLE(); |
| 655 | } |
| 656 | |
| 657 | return NULL; |
| 658 | } |
| 659 | |
| 660 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 661 | void MarkCompactCollector::ComputeEvacuationHeuristics( |
| 662 | int area_size, int* target_fragmentation_percent, |
| 663 | int* max_evacuated_bytes) { |
| 664 | // For memory reducing mode we directly define both constants. |
| 665 | const int kTargetFragmentationPercentForReduceMemory = 20; |
| 666 | const int kMaxEvacuatedBytesForReduceMemory = 12 * Page::kPageSize; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 667 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 668 | // For regular mode (which is latency critical) we define less aggressive |
| 669 | // defaults to start and switch to a trace-based (using compaction speed) |
| 670 | // approach as soon as we have enough samples. |
| 671 | const int kTargetFragmentationPercent = 70; |
| 672 | const int kMaxEvacuatedBytes = 4 * Page::kPageSize; |
| 673 | // Time to take for a single area (=payload of page). Used as soon as there |
| 674 | // exist enough compaction speed samples. |
| 675 | const int kTargetMsPerArea = 1; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 676 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 677 | if (heap()->ShouldReduceMemory()) { |
| 678 | *target_fragmentation_percent = kTargetFragmentationPercentForReduceMemory; |
| 679 | *max_evacuated_bytes = kMaxEvacuatedBytesForReduceMemory; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 680 | } else { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 681 | const intptr_t estimated_compaction_speed = |
| 682 | heap()->tracer()->CompactionSpeedInBytesPerMillisecond(); |
| 683 | if (estimated_compaction_speed != 0) { |
| 684 | // Estimate the target fragmentation based on traced compaction speed |
| 685 | // and a goal for a single page. |
| 686 | const intptr_t estimated_ms_per_area = |
| 687 | 1 + static_cast<intptr_t>(area_size) / estimated_compaction_speed; |
| 688 | *target_fragmentation_percent = |
| 689 | 100 - 100 * kTargetMsPerArea / estimated_ms_per_area; |
| 690 | if (*target_fragmentation_percent < |
| 691 | kTargetFragmentationPercentForReduceMemory) { |
| 692 | *target_fragmentation_percent = |
| 693 | kTargetFragmentationPercentForReduceMemory; |
| 694 | } |
| 695 | } else { |
| 696 | *target_fragmentation_percent = kTargetFragmentationPercent; |
| 697 | } |
| 698 | *max_evacuated_bytes = kMaxEvacuatedBytes; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 699 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 700 | } |
| 701 | |
| 702 | |
| 703 | void MarkCompactCollector::CollectEvacuationCandidates(PagedSpace* space) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 704 | DCHECK(space->identity() == OLD_SPACE || space->identity() == CODE_SPACE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 705 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 706 | int number_of_pages = space->CountTotalPages(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 707 | int area_size = space->AreaSize(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 708 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 709 | // Pairs of (live_bytes_in_page, page). |
| 710 | typedef std::pair<int, Page*> LiveBytesPagePair; |
| 711 | std::vector<LiveBytesPagePair> pages; |
| 712 | pages.reserve(number_of_pages); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 713 | |
| 714 | PageIterator it(space); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 715 | while (it.has_next()) { |
| 716 | Page* p = it.next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 717 | if (p->NeverEvacuate()) continue; |
| 718 | if (p->IsFlagSet(Page::POPULAR_PAGE)) { |
| 719 | // This page had slots buffer overflow on previous GC, skip it. |
| 720 | p->ClearFlag(Page::POPULAR_PAGE); |
| 721 | continue; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 722 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 723 | // Invariant: Evacuation candidates are just created when marking is |
| 724 | // started. At the end of a GC all evacuation candidates are cleared and |
| 725 | // their slot buffers are released. |
| 726 | CHECK(!p->IsEvacuationCandidate()); |
| 727 | CHECK(p->slots_buffer() == NULL); |
| 728 | DCHECK(p->area_size() == area_size); |
| 729 | int live_bytes = |
| 730 | p->WasSwept() ? p->LiveBytesFromFreeList() : p->LiveBytes(); |
| 731 | pages.push_back(std::make_pair(live_bytes, p)); |
| 732 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 733 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 734 | int candidate_count = 0; |
| 735 | int total_live_bytes = 0; |
| 736 | |
| 737 | const bool reduce_memory = heap()->ShouldReduceMemory(); |
| 738 | if (FLAG_manual_evacuation_candidates_selection) { |
| 739 | for (size_t i = 0; i < pages.size(); i++) { |
| 740 | Page* p = pages[i].second; |
| 741 | if (p->IsFlagSet(MemoryChunk::FORCE_EVACUATION_CANDIDATE_FOR_TESTING)) { |
| 742 | candidate_count++; |
| 743 | total_live_bytes += pages[i].first; |
| 744 | p->ClearFlag(MemoryChunk::FORCE_EVACUATION_CANDIDATE_FOR_TESTING); |
| 745 | AddEvacuationCandidate(p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 746 | } |
| 747 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 748 | } else if (FLAG_stress_compaction) { |
| 749 | for (size_t i = 0; i < pages.size(); i++) { |
| 750 | Page* p = pages[i].second; |
| 751 | if (i % 2 == 0) { |
| 752 | candidate_count++; |
| 753 | total_live_bytes += pages[i].first; |
| 754 | AddEvacuationCandidate(p); |
| 755 | } |
| 756 | } |
| 757 | } else { |
| 758 | // The following approach determines the pages that should be evacuated. |
| 759 | // |
| 760 | // We use two conditions to decide whether a page qualifies as an evacuation |
| 761 | // candidate, or not: |
| 762 | // * Target fragmentation: How fragmented is a page, i.e., how is the ratio |
| 763 | // between live bytes and capacity of this page (= area). |
| 764 | // * Evacuation quota: A global quota determining how much bytes should be |
| 765 | // compacted. |
| 766 | // |
| 767 | // The algorithm sorts all pages by live bytes and then iterates through |
| 768 | // them starting with the page with the most free memory, adding them to the |
| 769 | // set of evacuation candidates as long as both conditions (fragmentation |
| 770 | // and quota) hold. |
| 771 | int max_evacuated_bytes; |
| 772 | int target_fragmentation_percent; |
| 773 | ComputeEvacuationHeuristics(area_size, &target_fragmentation_percent, |
| 774 | &max_evacuated_bytes); |
| 775 | |
| 776 | const intptr_t free_bytes_threshold = |
| 777 | target_fragmentation_percent * (area_size / 100); |
| 778 | |
| 779 | // Sort pages from the most free to the least free, then select |
| 780 | // the first n pages for evacuation such that: |
| 781 | // - the total size of evacuated objects does not exceed the specified |
| 782 | // limit. |
| 783 | // - fragmentation of (n+1)-th page does not exceed the specified limit. |
| 784 | std::sort(pages.begin(), pages.end(), |
| 785 | [](const LiveBytesPagePair& a, const LiveBytesPagePair& b) { |
| 786 | return a.first < b.first; |
| 787 | }); |
| 788 | for (size_t i = 0; i < pages.size(); i++) { |
| 789 | int live_bytes = pages[i].first; |
| 790 | int free_bytes = area_size - live_bytes; |
| 791 | if (FLAG_always_compact || |
| 792 | ((free_bytes >= free_bytes_threshold) && |
| 793 | ((total_live_bytes + live_bytes) <= max_evacuated_bytes))) { |
| 794 | candidate_count++; |
| 795 | total_live_bytes += live_bytes; |
| 796 | } |
| 797 | if (FLAG_trace_fragmentation_verbose) { |
| 798 | PrintIsolate(isolate(), |
| 799 | "compaction-selection-page: space=%s free_bytes_page=%d " |
| 800 | "fragmentation_limit_kb=%d fragmentation_limit_percent=%d " |
| 801 | "sum_compaction_kb=%d " |
| 802 | "compaction_limit_kb=%d\n", |
| 803 | AllocationSpaceName(space->identity()), free_bytes / KB, |
| 804 | free_bytes_threshold / KB, target_fragmentation_percent, |
| 805 | total_live_bytes / KB, max_evacuated_bytes / KB); |
| 806 | } |
| 807 | } |
| 808 | // How many pages we will allocated for the evacuated objects |
| 809 | // in the worst case: ceil(total_live_bytes / area_size) |
| 810 | int estimated_new_pages = (total_live_bytes + area_size - 1) / area_size; |
| 811 | DCHECK_LE(estimated_new_pages, candidate_count); |
| 812 | int estimated_released_pages = candidate_count - estimated_new_pages; |
| 813 | // Avoid (compact -> expand) cycles. |
| 814 | if ((estimated_released_pages == 0) && !FLAG_always_compact) { |
| 815 | candidate_count = 0; |
| 816 | } |
| 817 | for (int i = 0; i < candidate_count; i++) { |
| 818 | AddEvacuationCandidate(pages[i].second); |
| 819 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 820 | } |
| 821 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 822 | if (FLAG_trace_fragmentation) { |
| 823 | PrintIsolate(isolate(), |
| 824 | "compaction-selection: space=%s reduce_memory=%d pages=%d " |
| 825 | "total_live_bytes=%d\n", |
| 826 | AllocationSpaceName(space->identity()), reduce_memory, |
| 827 | candidate_count, total_live_bytes / KB); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 828 | } |
| 829 | } |
| 830 | |
| 831 | |
| 832 | void MarkCompactCollector::AbortCompaction() { |
| 833 | if (compacting_) { |
| 834 | int npages = evacuation_candidates_.length(); |
| 835 | for (int i = 0; i < npages; i++) { |
| 836 | Page* p = evacuation_candidates_[i]; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 837 | slots_buffer_allocator_->DeallocateChain(p->slots_buffer_address()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 838 | p->ClearEvacuationCandidate(); |
| 839 | p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION); |
| 840 | } |
| 841 | compacting_ = false; |
| 842 | evacuation_candidates_.Rewind(0); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 843 | } |
| 844 | DCHECK_EQ(0, evacuation_candidates_.length()); |
| 845 | } |
| 846 | |
| 847 | |
| 848 | void MarkCompactCollector::Prepare() { |
| 849 | was_marked_incrementally_ = heap()->incremental_marking()->IsMarking(); |
| 850 | |
| 851 | #ifdef DEBUG |
| 852 | DCHECK(state_ == IDLE); |
| 853 | state_ = PREPARE_GC; |
| 854 | #endif |
| 855 | |
| 856 | DCHECK(!FLAG_never_compact || !FLAG_always_compact); |
| 857 | |
| 858 | if (sweeping_in_progress()) { |
| 859 | // Instead of waiting we could also abort the sweeper threads here. |
| 860 | EnsureSweepingCompleted(); |
| 861 | } |
| 862 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 863 | // If concurrent unmapping tasks are still running, we should wait for |
| 864 | // them here. |
| 865 | heap()->WaitUntilUnmappingOfFreeChunksCompleted(); |
| 866 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 867 | // Clear marking bits if incremental marking is aborted. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 868 | if (was_marked_incrementally_ && heap_->ShouldAbortIncrementalMarking()) { |
| 869 | heap()->incremental_marking()->Stop(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 870 | ClearMarkbits(); |
| 871 | AbortWeakCollections(); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 872 | AbortWeakCells(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 873 | AbortTransitionArrays(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 874 | AbortCompaction(); |
| 875 | was_marked_incrementally_ = false; |
| 876 | } |
| 877 | |
| 878 | // Don't start compaction if we are in the middle of incremental |
| 879 | // marking cycle. We did not collect any slots. |
| 880 | if (!FLAG_never_compact && !was_marked_incrementally_) { |
| 881 | StartCompaction(NON_INCREMENTAL_COMPACTION); |
| 882 | } |
| 883 | |
| 884 | PagedSpaces spaces(heap()); |
| 885 | for (PagedSpace* space = spaces.next(); space != NULL; |
| 886 | space = spaces.next()) { |
| 887 | space->PrepareForMarkCompact(); |
| 888 | } |
| 889 | |
| 890 | #ifdef VERIFY_HEAP |
| 891 | if (!was_marked_incrementally_ && FLAG_verify_heap) { |
| 892 | VerifyMarkbitsAreClean(); |
| 893 | } |
| 894 | #endif |
| 895 | } |
| 896 | |
| 897 | |
| 898 | void MarkCompactCollector::Finish() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 899 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_FINISH); |
| 900 | |
| 901 | // The hashing of weak_object_to_code_table is no longer valid. |
| 902 | heap()->weak_object_to_code_table()->Rehash( |
| 903 | heap()->isolate()->factory()->undefined_value()); |
| 904 | |
| 905 | // Clear the marking state of live large objects. |
| 906 | heap_->lo_space()->ClearMarkingStateOfLiveObjects(); |
| 907 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 908 | #ifdef DEBUG |
| 909 | DCHECK(state_ == SWEEP_SPACES || state_ == RELOCATE_OBJECTS); |
| 910 | state_ = IDLE; |
| 911 | #endif |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 912 | heap_->isolate()->inner_pointer_to_code_cache()->Flush(); |
| 913 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 914 | // The stub cache is not traversed during GC; clear the cache to |
| 915 | // force lazy re-initialization of it. This must be done after the |
| 916 | // GC, because it relies on the new address of certain old space |
| 917 | // objects (empty string, illegal builtin). |
| 918 | isolate()->stub_cache()->Clear(); |
| 919 | |
| 920 | if (have_code_to_deoptimize_) { |
| 921 | // Some code objects were marked for deoptimization during the GC. |
| 922 | Deoptimizer::DeoptimizeMarkedCode(isolate()); |
| 923 | have_code_to_deoptimize_ = false; |
| 924 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 925 | |
| 926 | heap_->incremental_marking()->ClearIdleMarkingDelayCounter(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 927 | |
| 928 | if (marking_parity_ == EVEN_MARKING_PARITY) { |
| 929 | marking_parity_ = ODD_MARKING_PARITY; |
| 930 | } else { |
| 931 | DCHECK(marking_parity_ == ODD_MARKING_PARITY); |
| 932 | marking_parity_ = EVEN_MARKING_PARITY; |
| 933 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 934 | } |
| 935 | |
| 936 | |
| 937 | // ------------------------------------------------------------------------- |
| 938 | // Phase 1: tracing and marking live objects. |
| 939 | // before: all objects are in normal state. |
| 940 | // after: a live object's map pointer is marked as '00'. |
| 941 | |
| 942 | // Marking all live objects in the heap as part of mark-sweep or mark-compact |
| 943 | // collection. Before marking, all objects are in their normal state. After |
| 944 | // marking, live objects' map pointers are marked indicating that the object |
| 945 | // has been found reachable. |
| 946 | // |
| 947 | // The marking algorithm is a (mostly) depth-first (because of possible stack |
| 948 | // overflow) traversal of the graph of objects reachable from the roots. It |
| 949 | // uses an explicit stack of pointers rather than recursion. The young |
| 950 | // generation's inactive ('from') space is used as a marking stack. The |
| 951 | // objects in the marking stack are the ones that have been reached and marked |
| 952 | // but their children have not yet been visited. |
| 953 | // |
| 954 | // The marking stack can overflow during traversal. In that case, we set an |
| 955 | // overflow flag. When the overflow flag is set, we continue marking objects |
| 956 | // reachable from the objects on the marking stack, but no longer push them on |
| 957 | // the marking stack. Instead, we mark them as both marked and overflowed. |
| 958 | // When the stack is in the overflowed state, objects marked as overflowed |
| 959 | // have been reached and marked but their children have not been visited yet. |
| 960 | // After emptying the marking stack, we clear the overflow flag and traverse |
| 961 | // the heap looking for objects marked as overflowed, push them on the stack, |
| 962 | // and continue with marking. This process repeats until all reachable |
| 963 | // objects have been marked. |
| 964 | |
| 965 | void CodeFlusher::ProcessJSFunctionCandidates() { |
| 966 | Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy); |
| 967 | Object* undefined = isolate_->heap()->undefined_value(); |
| 968 | |
| 969 | JSFunction* candidate = jsfunction_candidates_head_; |
| 970 | JSFunction* next_candidate; |
| 971 | while (candidate != NULL) { |
| 972 | next_candidate = GetNextCandidate(candidate); |
| 973 | ClearNextCandidate(candidate, undefined); |
| 974 | |
| 975 | SharedFunctionInfo* shared = candidate->shared(); |
| 976 | |
| 977 | Code* code = shared->code(); |
| 978 | MarkBit code_mark = Marking::MarkBitFrom(code); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 979 | if (Marking::IsWhite(code_mark)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 980 | if (FLAG_trace_code_flushing && shared->is_compiled()) { |
| 981 | PrintF("[code-flushing clears: "); |
| 982 | shared->ShortPrint(); |
| 983 | PrintF(" - age: %d]\n", code->GetAge()); |
| 984 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 985 | // Always flush the optimized code map if there is one. |
| 986 | if (!shared->OptimizedCodeMapIsCleared()) { |
| 987 | shared->ClearOptimizedCodeMap(); |
| 988 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 989 | shared->set_code(lazy_compile); |
| 990 | candidate->set_code(lazy_compile); |
| 991 | } else { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 992 | DCHECK(Marking::IsBlack(code_mark)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 993 | candidate->set_code(code); |
| 994 | } |
| 995 | |
| 996 | // We are in the middle of a GC cycle so the write barrier in the code |
| 997 | // setter did not record the slot update and we have to do that manually. |
| 998 | Address slot = candidate->address() + JSFunction::kCodeEntryOffset; |
| 999 | Code* target = Code::cast(Code::GetObjectFromEntryAddress(slot)); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1000 | isolate_->heap()->mark_compact_collector()->RecordCodeEntrySlot( |
| 1001 | candidate, slot, target); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1002 | |
| 1003 | Object** shared_code_slot = |
| 1004 | HeapObject::RawField(shared, SharedFunctionInfo::kCodeOffset); |
| 1005 | isolate_->heap()->mark_compact_collector()->RecordSlot( |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1006 | shared, shared_code_slot, *shared_code_slot); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1007 | |
| 1008 | candidate = next_candidate; |
| 1009 | } |
| 1010 | |
| 1011 | jsfunction_candidates_head_ = NULL; |
| 1012 | } |
| 1013 | |
| 1014 | |
| 1015 | void CodeFlusher::ProcessSharedFunctionInfoCandidates() { |
| 1016 | Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy); |
| 1017 | |
| 1018 | SharedFunctionInfo* candidate = shared_function_info_candidates_head_; |
| 1019 | SharedFunctionInfo* next_candidate; |
| 1020 | while (candidate != NULL) { |
| 1021 | next_candidate = GetNextCandidate(candidate); |
| 1022 | ClearNextCandidate(candidate); |
| 1023 | |
| 1024 | Code* code = candidate->code(); |
| 1025 | MarkBit code_mark = Marking::MarkBitFrom(code); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1026 | if (Marking::IsWhite(code_mark)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1027 | if (FLAG_trace_code_flushing && candidate->is_compiled()) { |
| 1028 | PrintF("[code-flushing clears: "); |
| 1029 | candidate->ShortPrint(); |
| 1030 | PrintF(" - age: %d]\n", code->GetAge()); |
| 1031 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1032 | // Always flush the optimized code map if there is one. |
| 1033 | if (!candidate->OptimizedCodeMapIsCleared()) { |
| 1034 | candidate->ClearOptimizedCodeMap(); |
| 1035 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1036 | candidate->set_code(lazy_compile); |
| 1037 | } |
| 1038 | |
| 1039 | Object** code_slot = |
| 1040 | HeapObject::RawField(candidate, SharedFunctionInfo::kCodeOffset); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1041 | isolate_->heap()->mark_compact_collector()->RecordSlot(candidate, code_slot, |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1042 | *code_slot); |
| 1043 | |
| 1044 | candidate = next_candidate; |
| 1045 | } |
| 1046 | |
| 1047 | shared_function_info_candidates_head_ = NULL; |
| 1048 | } |
| 1049 | |
| 1050 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1051 | void CodeFlusher::EvictCandidate(SharedFunctionInfo* shared_info) { |
| 1052 | // Make sure previous flushing decisions are revisited. |
| 1053 | isolate_->heap()->incremental_marking()->RecordWrites(shared_info); |
| 1054 | |
| 1055 | if (FLAG_trace_code_flushing) { |
| 1056 | PrintF("[code-flushing abandons function-info: "); |
| 1057 | shared_info->ShortPrint(); |
| 1058 | PrintF("]\n"); |
| 1059 | } |
| 1060 | |
| 1061 | SharedFunctionInfo* candidate = shared_function_info_candidates_head_; |
| 1062 | SharedFunctionInfo* next_candidate; |
| 1063 | if (candidate == shared_info) { |
| 1064 | next_candidate = GetNextCandidate(shared_info); |
| 1065 | shared_function_info_candidates_head_ = next_candidate; |
| 1066 | ClearNextCandidate(shared_info); |
| 1067 | } else { |
| 1068 | while (candidate != NULL) { |
| 1069 | next_candidate = GetNextCandidate(candidate); |
| 1070 | |
| 1071 | if (next_candidate == shared_info) { |
| 1072 | next_candidate = GetNextCandidate(shared_info); |
| 1073 | SetNextCandidate(candidate, next_candidate); |
| 1074 | ClearNextCandidate(shared_info); |
| 1075 | break; |
| 1076 | } |
| 1077 | |
| 1078 | candidate = next_candidate; |
| 1079 | } |
| 1080 | } |
| 1081 | } |
| 1082 | |
| 1083 | |
| 1084 | void CodeFlusher::EvictCandidate(JSFunction* function) { |
| 1085 | DCHECK(!function->next_function_link()->IsUndefined()); |
| 1086 | Object* undefined = isolate_->heap()->undefined_value(); |
| 1087 | |
| 1088 | // Make sure previous flushing decisions are revisited. |
| 1089 | isolate_->heap()->incremental_marking()->RecordWrites(function); |
| 1090 | isolate_->heap()->incremental_marking()->RecordWrites(function->shared()); |
| 1091 | |
| 1092 | if (FLAG_trace_code_flushing) { |
| 1093 | PrintF("[code-flushing abandons closure: "); |
| 1094 | function->shared()->ShortPrint(); |
| 1095 | PrintF("]\n"); |
| 1096 | } |
| 1097 | |
| 1098 | JSFunction* candidate = jsfunction_candidates_head_; |
| 1099 | JSFunction* next_candidate; |
| 1100 | if (candidate == function) { |
| 1101 | next_candidate = GetNextCandidate(function); |
| 1102 | jsfunction_candidates_head_ = next_candidate; |
| 1103 | ClearNextCandidate(function, undefined); |
| 1104 | } else { |
| 1105 | while (candidate != NULL) { |
| 1106 | next_candidate = GetNextCandidate(candidate); |
| 1107 | |
| 1108 | if (next_candidate == function) { |
| 1109 | next_candidate = GetNextCandidate(function); |
| 1110 | SetNextCandidate(candidate, next_candidate); |
| 1111 | ClearNextCandidate(function, undefined); |
| 1112 | break; |
| 1113 | } |
| 1114 | |
| 1115 | candidate = next_candidate; |
| 1116 | } |
| 1117 | } |
| 1118 | } |
| 1119 | |
| 1120 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1121 | void CodeFlusher::IteratePointersToFromSpace(ObjectVisitor* v) { |
| 1122 | Heap* heap = isolate_->heap(); |
| 1123 | |
| 1124 | JSFunction** slot = &jsfunction_candidates_head_; |
| 1125 | JSFunction* candidate = jsfunction_candidates_head_; |
| 1126 | while (candidate != NULL) { |
| 1127 | if (heap->InFromSpace(candidate)) { |
| 1128 | v->VisitPointer(reinterpret_cast<Object**>(slot)); |
| 1129 | } |
| 1130 | candidate = GetNextCandidate(*slot); |
| 1131 | slot = GetNextCandidateSlot(*slot); |
| 1132 | } |
| 1133 | } |
| 1134 | |
| 1135 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1136 | class MarkCompactMarkingVisitor |
| 1137 | : public StaticMarkingVisitor<MarkCompactMarkingVisitor> { |
| 1138 | public: |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1139 | static void Initialize(); |
| 1140 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1141 | INLINE(static void VisitPointer(Heap* heap, HeapObject* object, Object** p)) { |
| 1142 | MarkObjectByPointer(heap->mark_compact_collector(), object, p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1143 | } |
| 1144 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1145 | INLINE(static void VisitPointers(Heap* heap, HeapObject* object, |
| 1146 | Object** start, Object** end)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1147 | // Mark all objects pointed to in [start, end). |
| 1148 | const int kMinRangeForMarkingRecursion = 64; |
| 1149 | if (end - start >= kMinRangeForMarkingRecursion) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1150 | if (VisitUnmarkedObjects(heap, object, start, end)) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1151 | // We are close to a stack overflow, so just mark the objects. |
| 1152 | } |
| 1153 | MarkCompactCollector* collector = heap->mark_compact_collector(); |
| 1154 | for (Object** p = start; p < end; p++) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1155 | MarkObjectByPointer(collector, object, p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1156 | } |
| 1157 | } |
| 1158 | |
| 1159 | // Marks the object black and pushes it on the marking stack. |
| 1160 | INLINE(static void MarkObject(Heap* heap, HeapObject* object)) { |
| 1161 | MarkBit mark = Marking::MarkBitFrom(object); |
| 1162 | heap->mark_compact_collector()->MarkObject(object, mark); |
| 1163 | } |
| 1164 | |
| 1165 | // Marks the object black without pushing it on the marking stack. |
| 1166 | // Returns true if object needed marking and false otherwise. |
| 1167 | INLINE(static bool MarkObjectWithoutPush(Heap* heap, HeapObject* object)) { |
| 1168 | MarkBit mark_bit = Marking::MarkBitFrom(object); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1169 | if (Marking::IsWhite(mark_bit)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1170 | heap->mark_compact_collector()->SetMark(object, mark_bit); |
| 1171 | return true; |
| 1172 | } |
| 1173 | return false; |
| 1174 | } |
| 1175 | |
| 1176 | // Mark object pointed to by p. |
| 1177 | INLINE(static void MarkObjectByPointer(MarkCompactCollector* collector, |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1178 | HeapObject* object, Object** p)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1179 | if (!(*p)->IsHeapObject()) return; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1180 | HeapObject* target_object = HeapObject::cast(*p); |
| 1181 | collector->RecordSlot(object, p, target_object); |
| 1182 | MarkBit mark = Marking::MarkBitFrom(target_object); |
| 1183 | collector->MarkObject(target_object, mark); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1184 | } |
| 1185 | |
| 1186 | |
| 1187 | // Visit an unmarked object. |
| 1188 | INLINE(static void VisitUnmarkedObject(MarkCompactCollector* collector, |
| 1189 | HeapObject* obj)) { |
| 1190 | #ifdef DEBUG |
| 1191 | DCHECK(collector->heap()->Contains(obj)); |
| 1192 | DCHECK(!collector->heap()->mark_compact_collector()->IsMarked(obj)); |
| 1193 | #endif |
| 1194 | Map* map = obj->map(); |
| 1195 | Heap* heap = obj->GetHeap(); |
| 1196 | MarkBit mark = Marking::MarkBitFrom(obj); |
| 1197 | heap->mark_compact_collector()->SetMark(obj, mark); |
| 1198 | // Mark the map pointer and the body. |
| 1199 | MarkBit map_mark = Marking::MarkBitFrom(map); |
| 1200 | heap->mark_compact_collector()->MarkObject(map, map_mark); |
| 1201 | IterateBody(map, obj); |
| 1202 | } |
| 1203 | |
| 1204 | // Visit all unmarked objects pointed to by [start, end). |
| 1205 | // Returns false if the operation fails (lack of stack space). |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1206 | INLINE(static bool VisitUnmarkedObjects(Heap* heap, HeapObject* object, |
| 1207 | Object** start, Object** end)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1208 | // Return false is we are close to the stack limit. |
| 1209 | StackLimitCheck check(heap->isolate()); |
| 1210 | if (check.HasOverflowed()) return false; |
| 1211 | |
| 1212 | MarkCompactCollector* collector = heap->mark_compact_collector(); |
| 1213 | // Visit the unmarked objects. |
| 1214 | for (Object** p = start; p < end; p++) { |
| 1215 | Object* o = *p; |
| 1216 | if (!o->IsHeapObject()) continue; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1217 | collector->RecordSlot(object, p, o); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1218 | HeapObject* obj = HeapObject::cast(o); |
| 1219 | MarkBit mark = Marking::MarkBitFrom(obj); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1220 | if (Marking::IsBlackOrGrey(mark)) continue; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1221 | VisitUnmarkedObject(collector, obj); |
| 1222 | } |
| 1223 | return true; |
| 1224 | } |
| 1225 | |
| 1226 | private: |
| 1227 | template <int id> |
| 1228 | static inline void TrackObjectStatsAndVisit(Map* map, HeapObject* obj); |
| 1229 | |
| 1230 | // Code flushing support. |
| 1231 | |
| 1232 | static const int kRegExpCodeThreshold = 5; |
| 1233 | |
| 1234 | static void UpdateRegExpCodeAgeAndFlush(Heap* heap, JSRegExp* re, |
| 1235 | bool is_one_byte) { |
| 1236 | // Make sure that the fixed array is in fact initialized on the RegExp. |
| 1237 | // We could potentially trigger a GC when initializing the RegExp. |
| 1238 | if (HeapObject::cast(re->data())->map()->instance_type() != |
| 1239 | FIXED_ARRAY_TYPE) |
| 1240 | return; |
| 1241 | |
| 1242 | // Make sure this is a RegExp that actually contains code. |
| 1243 | if (re->TypeTag() != JSRegExp::IRREGEXP) return; |
| 1244 | |
| 1245 | Object* code = re->DataAt(JSRegExp::code_index(is_one_byte)); |
| 1246 | if (!code->IsSmi() && |
| 1247 | HeapObject::cast(code)->map()->instance_type() == CODE_TYPE) { |
| 1248 | // Save a copy that can be reinstated if we need the code again. |
| 1249 | re->SetDataAt(JSRegExp::saved_code_index(is_one_byte), code); |
| 1250 | |
| 1251 | // Saving a copy might create a pointer into compaction candidate |
| 1252 | // that was not observed by marker. This might happen if JSRegExp data |
| 1253 | // was marked through the compilation cache before marker reached JSRegExp |
| 1254 | // object. |
| 1255 | FixedArray* data = FixedArray::cast(re->data()); |
| 1256 | Object** slot = |
| 1257 | data->data_start() + JSRegExp::saved_code_index(is_one_byte); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1258 | heap->mark_compact_collector()->RecordSlot(data, slot, code); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1259 | |
| 1260 | // Set a number in the 0-255 range to guarantee no smi overflow. |
| 1261 | re->SetDataAt(JSRegExp::code_index(is_one_byte), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1262 | Smi::FromInt(heap->ms_count() & 0xff)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1263 | } else if (code->IsSmi()) { |
| 1264 | int value = Smi::cast(code)->value(); |
| 1265 | // The regexp has not been compiled yet or there was a compilation error. |
| 1266 | if (value == JSRegExp::kUninitializedValue || |
| 1267 | value == JSRegExp::kCompilationErrorValue) { |
| 1268 | return; |
| 1269 | } |
| 1270 | |
| 1271 | // Check if we should flush now. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1272 | if (value == ((heap->ms_count() - kRegExpCodeThreshold) & 0xff)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1273 | re->SetDataAt(JSRegExp::code_index(is_one_byte), |
| 1274 | Smi::FromInt(JSRegExp::kUninitializedValue)); |
| 1275 | re->SetDataAt(JSRegExp::saved_code_index(is_one_byte), |
| 1276 | Smi::FromInt(JSRegExp::kUninitializedValue)); |
| 1277 | } |
| 1278 | } |
| 1279 | } |
| 1280 | |
| 1281 | |
| 1282 | // Works by setting the current sweep_generation (as a smi) in the |
| 1283 | // code object place in the data array of the RegExp and keeps a copy |
| 1284 | // around that can be reinstated if we reuse the RegExp before flushing. |
| 1285 | // If we did not use the code for kRegExpCodeThreshold mark sweep GCs |
| 1286 | // we flush the code. |
| 1287 | static void VisitRegExpAndFlushCode(Map* map, HeapObject* object) { |
| 1288 | Heap* heap = map->GetHeap(); |
| 1289 | MarkCompactCollector* collector = heap->mark_compact_collector(); |
| 1290 | if (!collector->is_code_flushing_enabled()) { |
| 1291 | VisitJSRegExp(map, object); |
| 1292 | return; |
| 1293 | } |
| 1294 | JSRegExp* re = reinterpret_cast<JSRegExp*>(object); |
| 1295 | // Flush code or set age on both one byte and two byte code. |
| 1296 | UpdateRegExpCodeAgeAndFlush(heap, re, true); |
| 1297 | UpdateRegExpCodeAgeAndFlush(heap, re, false); |
| 1298 | // Visit the fields of the RegExp, including the updated FixedArray. |
| 1299 | VisitJSRegExp(map, object); |
| 1300 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1301 | }; |
| 1302 | |
| 1303 | |
| 1304 | void MarkCompactMarkingVisitor::Initialize() { |
| 1305 | StaticMarkingVisitor<MarkCompactMarkingVisitor>::Initialize(); |
| 1306 | |
| 1307 | table_.Register(kVisitJSRegExp, &VisitRegExpAndFlushCode); |
| 1308 | |
| 1309 | if (FLAG_track_gc_object_stats) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1310 | ObjectStatsVisitor::Initialize(&table_); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1311 | } |
| 1312 | } |
| 1313 | |
| 1314 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1315 | class CodeMarkingVisitor : public ThreadVisitor { |
| 1316 | public: |
| 1317 | explicit CodeMarkingVisitor(MarkCompactCollector* collector) |
| 1318 | : collector_(collector) {} |
| 1319 | |
| 1320 | void VisitThread(Isolate* isolate, ThreadLocalTop* top) { |
| 1321 | collector_->PrepareThreadForCodeFlushing(isolate, top); |
| 1322 | } |
| 1323 | |
| 1324 | private: |
| 1325 | MarkCompactCollector* collector_; |
| 1326 | }; |
| 1327 | |
| 1328 | |
| 1329 | class SharedFunctionInfoMarkingVisitor : public ObjectVisitor { |
| 1330 | public: |
| 1331 | explicit SharedFunctionInfoMarkingVisitor(MarkCompactCollector* collector) |
| 1332 | : collector_(collector) {} |
| 1333 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1334 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1335 | for (Object** p = start; p < end; p++) VisitPointer(p); |
| 1336 | } |
| 1337 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1338 | void VisitPointer(Object** slot) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1339 | Object* obj = *slot; |
| 1340 | if (obj->IsSharedFunctionInfo()) { |
| 1341 | SharedFunctionInfo* shared = reinterpret_cast<SharedFunctionInfo*>(obj); |
| 1342 | MarkBit shared_mark = Marking::MarkBitFrom(shared); |
| 1343 | MarkBit code_mark = Marking::MarkBitFrom(shared->code()); |
| 1344 | collector_->MarkObject(shared->code(), code_mark); |
| 1345 | collector_->MarkObject(shared, shared_mark); |
| 1346 | } |
| 1347 | } |
| 1348 | |
| 1349 | private: |
| 1350 | MarkCompactCollector* collector_; |
| 1351 | }; |
| 1352 | |
| 1353 | |
| 1354 | void MarkCompactCollector::PrepareThreadForCodeFlushing(Isolate* isolate, |
| 1355 | ThreadLocalTop* top) { |
| 1356 | for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) { |
| 1357 | // Note: for the frame that has a pending lazy deoptimization |
| 1358 | // StackFrame::unchecked_code will return a non-optimized code object for |
| 1359 | // the outermost function and StackFrame::LookupCode will return |
| 1360 | // actual optimized code object. |
| 1361 | StackFrame* frame = it.frame(); |
| 1362 | Code* code = frame->unchecked_code(); |
| 1363 | MarkBit code_mark = Marking::MarkBitFrom(code); |
| 1364 | MarkObject(code, code_mark); |
| 1365 | if (frame->is_optimized()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1366 | Code* optimized_code = frame->LookupCode(); |
| 1367 | MarkBit optimized_code_mark = Marking::MarkBitFrom(optimized_code); |
| 1368 | MarkObject(optimized_code, optimized_code_mark); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1369 | } |
| 1370 | } |
| 1371 | } |
| 1372 | |
| 1373 | |
| 1374 | void MarkCompactCollector::PrepareForCodeFlushing() { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1375 | // If code flushing is disabled, there is no need to prepare for it. |
| 1376 | if (!is_code_flushing_enabled()) return; |
| 1377 | |
| 1378 | // Ensure that empty descriptor array is marked. Method MarkDescriptorArray |
| 1379 | // relies on it being marked before any other descriptor array. |
| 1380 | HeapObject* descriptor_array = heap()->empty_descriptor_array(); |
| 1381 | MarkBit descriptor_array_mark = Marking::MarkBitFrom(descriptor_array); |
| 1382 | MarkObject(descriptor_array, descriptor_array_mark); |
| 1383 | |
| 1384 | // Make sure we are not referencing the code from the stack. |
| 1385 | DCHECK(this == heap()->mark_compact_collector()); |
| 1386 | PrepareThreadForCodeFlushing(heap()->isolate(), |
| 1387 | heap()->isolate()->thread_local_top()); |
| 1388 | |
| 1389 | // Iterate the archived stacks in all threads to check if |
| 1390 | // the code is referenced. |
| 1391 | CodeMarkingVisitor code_marking_visitor(this); |
| 1392 | heap()->isolate()->thread_manager()->IterateArchivedThreads( |
| 1393 | &code_marking_visitor); |
| 1394 | |
| 1395 | SharedFunctionInfoMarkingVisitor visitor(this); |
| 1396 | heap()->isolate()->compilation_cache()->IterateFunctions(&visitor); |
| 1397 | heap()->isolate()->handle_scope_implementer()->Iterate(&visitor); |
| 1398 | |
| 1399 | ProcessMarkingDeque(); |
| 1400 | } |
| 1401 | |
| 1402 | |
| 1403 | // Visitor class for marking heap roots. |
| 1404 | class RootMarkingVisitor : public ObjectVisitor { |
| 1405 | public: |
| 1406 | explicit RootMarkingVisitor(Heap* heap) |
| 1407 | : collector_(heap->mark_compact_collector()) {} |
| 1408 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1409 | void VisitPointer(Object** p) override { MarkObjectByPointer(p); } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1410 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1411 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1412 | for (Object** p = start; p < end; p++) MarkObjectByPointer(p); |
| 1413 | } |
| 1414 | |
| 1415 | // Skip the weak next code link in a code object, which is visited in |
| 1416 | // ProcessTopOptimizedFrame. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1417 | void VisitNextCodeLink(Object** p) override {} |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1418 | |
| 1419 | private: |
| 1420 | void MarkObjectByPointer(Object** p) { |
| 1421 | if (!(*p)->IsHeapObject()) return; |
| 1422 | |
| 1423 | // Replace flat cons strings in place. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1424 | HeapObject* object = HeapObject::cast(*p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1425 | MarkBit mark_bit = Marking::MarkBitFrom(object); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1426 | if (Marking::IsBlackOrGrey(mark_bit)) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1427 | |
| 1428 | Map* map = object->map(); |
| 1429 | // Mark the object. |
| 1430 | collector_->SetMark(object, mark_bit); |
| 1431 | |
| 1432 | // Mark the map pointer and body, and push them on the marking stack. |
| 1433 | MarkBit map_mark = Marking::MarkBitFrom(map); |
| 1434 | collector_->MarkObject(map, map_mark); |
| 1435 | MarkCompactMarkingVisitor::IterateBody(map, object); |
| 1436 | |
| 1437 | // Mark all the objects reachable from the map and body. May leave |
| 1438 | // overflowed objects in the heap. |
| 1439 | collector_->EmptyMarkingDeque(); |
| 1440 | } |
| 1441 | |
| 1442 | MarkCompactCollector* collector_; |
| 1443 | }; |
| 1444 | |
| 1445 | |
| 1446 | // Helper class for pruning the string table. |
| 1447 | template <bool finalize_external_strings> |
| 1448 | class StringTableCleaner : public ObjectVisitor { |
| 1449 | public: |
| 1450 | explicit StringTableCleaner(Heap* heap) : heap_(heap), pointers_removed_(0) {} |
| 1451 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1452 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1453 | // Visit all HeapObject pointers in [start, end). |
| 1454 | for (Object** p = start; p < end; p++) { |
| 1455 | Object* o = *p; |
| 1456 | if (o->IsHeapObject() && |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1457 | Marking::IsWhite(Marking::MarkBitFrom(HeapObject::cast(o)))) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1458 | if (finalize_external_strings) { |
| 1459 | DCHECK(o->IsExternalString()); |
| 1460 | heap_->FinalizeExternalString(String::cast(*p)); |
| 1461 | } else { |
| 1462 | pointers_removed_++; |
| 1463 | } |
| 1464 | // Set the entry to the_hole_value (as deleted). |
| 1465 | *p = heap_->the_hole_value(); |
| 1466 | } |
| 1467 | } |
| 1468 | } |
| 1469 | |
| 1470 | int PointersRemoved() { |
| 1471 | DCHECK(!finalize_external_strings); |
| 1472 | return pointers_removed_; |
| 1473 | } |
| 1474 | |
| 1475 | private: |
| 1476 | Heap* heap_; |
| 1477 | int pointers_removed_; |
| 1478 | }; |
| 1479 | |
| 1480 | |
| 1481 | typedef StringTableCleaner<false> InternalizedStringTableCleaner; |
| 1482 | typedef StringTableCleaner<true> ExternalStringTableCleaner; |
| 1483 | |
| 1484 | |
| 1485 | // Implementation of WeakObjectRetainer for mark compact GCs. All marked objects |
| 1486 | // are retained. |
| 1487 | class MarkCompactWeakObjectRetainer : public WeakObjectRetainer { |
| 1488 | public: |
| 1489 | virtual Object* RetainAs(Object* object) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1490 | MarkBit mark_bit = Marking::MarkBitFrom(HeapObject::cast(object)); |
| 1491 | DCHECK(!Marking::IsGrey(mark_bit)); |
| 1492 | if (Marking::IsBlack(mark_bit)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1493 | return object; |
| 1494 | } else if (object->IsAllocationSite() && |
| 1495 | !(AllocationSite::cast(object)->IsZombie())) { |
| 1496 | // "dead" AllocationSites need to live long enough for a traversal of new |
| 1497 | // space. These sites get a one-time reprieve. |
| 1498 | AllocationSite* site = AllocationSite::cast(object); |
| 1499 | site->MarkZombie(); |
| 1500 | site->GetHeap()->mark_compact_collector()->MarkAllocationSite(site); |
| 1501 | return object; |
| 1502 | } else { |
| 1503 | return NULL; |
| 1504 | } |
| 1505 | } |
| 1506 | }; |
| 1507 | |
| 1508 | |
| 1509 | // Fill the marking stack with overflowed objects returned by the given |
| 1510 | // iterator. Stop when the marking stack is filled or the end of the space |
| 1511 | // is reached, whichever comes first. |
| 1512 | template <class T> |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1513 | void MarkCompactCollector::DiscoverGreyObjectsWithIterator(T* it) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1514 | // The caller should ensure that the marking stack is initially not full, |
| 1515 | // so that we don't waste effort pointlessly scanning for objects. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1516 | DCHECK(!marking_deque()->IsFull()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1517 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1518 | Map* filler_map = heap()->one_pointer_filler_map(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1519 | for (HeapObject* object = it->Next(); object != NULL; object = it->Next()) { |
| 1520 | MarkBit markbit = Marking::MarkBitFrom(object); |
| 1521 | if ((object->map() != filler_map) && Marking::IsGrey(markbit)) { |
| 1522 | Marking::GreyToBlack(markbit); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1523 | PushBlack(object); |
| 1524 | if (marking_deque()->IsFull()) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1525 | } |
| 1526 | } |
| 1527 | } |
| 1528 | |
| 1529 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1530 | void MarkCompactCollector::DiscoverGreyObjectsOnPage(MemoryChunk* p) { |
| 1531 | DCHECK(!marking_deque()->IsFull()); |
| 1532 | LiveObjectIterator<kGreyObjects> it(p); |
| 1533 | HeapObject* object = NULL; |
| 1534 | while ((object = it.Next()) != NULL) { |
| 1535 | MarkBit markbit = Marking::MarkBitFrom(object); |
| 1536 | DCHECK(Marking::IsGrey(markbit)); |
| 1537 | Marking::GreyToBlack(markbit); |
| 1538 | PushBlack(object); |
| 1539 | if (marking_deque()->IsFull()) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1540 | } |
| 1541 | } |
| 1542 | |
| 1543 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1544 | class MarkCompactCollector::HeapObjectVisitor { |
| 1545 | public: |
| 1546 | virtual ~HeapObjectVisitor() {} |
| 1547 | virtual bool Visit(HeapObject* object) = 0; |
| 1548 | }; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1549 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1550 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1551 | class MarkCompactCollector::EvacuateVisitorBase |
| 1552 | : public MarkCompactCollector::HeapObjectVisitor { |
| 1553 | public: |
| 1554 | EvacuateVisitorBase(Heap* heap, SlotsBuffer** evacuation_slots_buffer) |
| 1555 | : heap_(heap), evacuation_slots_buffer_(evacuation_slots_buffer) {} |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1556 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1557 | bool TryEvacuateObject(PagedSpace* target_space, HeapObject* object, |
| 1558 | HeapObject** target_object) { |
| 1559 | int size = object->Size(); |
| 1560 | AllocationAlignment alignment = object->RequiredAlignment(); |
| 1561 | AllocationResult allocation = target_space->AllocateRaw(size, alignment); |
| 1562 | if (allocation.To(target_object)) { |
| 1563 | heap_->mark_compact_collector()->MigrateObject( |
| 1564 | *target_object, object, size, target_space->identity(), |
| 1565 | evacuation_slots_buffer_); |
| 1566 | return true; |
| 1567 | } |
| 1568 | return false; |
| 1569 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1570 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1571 | protected: |
| 1572 | Heap* heap_; |
| 1573 | SlotsBuffer** evacuation_slots_buffer_; |
| 1574 | }; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1575 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1576 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1577 | class MarkCompactCollector::EvacuateNewSpaceVisitor final |
| 1578 | : public MarkCompactCollector::EvacuateVisitorBase { |
| 1579 | public: |
| 1580 | static const intptr_t kLabSize = 4 * KB; |
| 1581 | static const intptr_t kMaxLabObjectSize = 256; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1582 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1583 | explicit EvacuateNewSpaceVisitor(Heap* heap, |
| 1584 | SlotsBuffer** evacuation_slots_buffer, |
| 1585 | HashMap* local_pretenuring_feedback) |
| 1586 | : EvacuateVisitorBase(heap, evacuation_slots_buffer), |
| 1587 | buffer_(LocalAllocationBuffer::InvalidBuffer()), |
| 1588 | space_to_allocate_(NEW_SPACE), |
| 1589 | promoted_size_(0), |
| 1590 | semispace_copied_size_(0), |
| 1591 | local_pretenuring_feedback_(local_pretenuring_feedback) {} |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1592 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1593 | bool Visit(HeapObject* object) override { |
| 1594 | heap_->UpdateAllocationSite(object, local_pretenuring_feedback_); |
| 1595 | int size = object->Size(); |
| 1596 | HeapObject* target_object = nullptr; |
| 1597 | if (heap_->ShouldBePromoted(object->address(), size) && |
| 1598 | TryEvacuateObject(heap_->old_space(), object, &target_object)) { |
| 1599 | // If we end up needing more special cases, we should factor this out. |
| 1600 | if (V8_UNLIKELY(target_object->IsJSArrayBuffer())) { |
| 1601 | heap_->array_buffer_tracker()->Promote( |
| 1602 | JSArrayBuffer::cast(target_object)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1603 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1604 | promoted_size_ += size; |
| 1605 | return true; |
| 1606 | } |
| 1607 | HeapObject* target = nullptr; |
| 1608 | AllocationSpace space = AllocateTargetObject(object, &target); |
| 1609 | heap_->mark_compact_collector()->MigrateObject( |
| 1610 | HeapObject::cast(target), object, size, space, |
| 1611 | (space == NEW_SPACE) ? nullptr : evacuation_slots_buffer_); |
| 1612 | if (V8_UNLIKELY(target->IsJSArrayBuffer())) { |
| 1613 | heap_->array_buffer_tracker()->MarkLive(JSArrayBuffer::cast(target)); |
| 1614 | } |
| 1615 | semispace_copied_size_ += size; |
| 1616 | return true; |
| 1617 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1618 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1619 | intptr_t promoted_size() { return promoted_size_; } |
| 1620 | intptr_t semispace_copied_size() { return semispace_copied_size_; } |
| 1621 | |
| 1622 | private: |
| 1623 | enum NewSpaceAllocationMode { |
| 1624 | kNonstickyBailoutOldSpace, |
| 1625 | kStickyBailoutOldSpace, |
| 1626 | }; |
| 1627 | |
| 1628 | inline AllocationSpace AllocateTargetObject(HeapObject* old_object, |
| 1629 | HeapObject** target_object) { |
| 1630 | const int size = old_object->Size(); |
| 1631 | AllocationAlignment alignment = old_object->RequiredAlignment(); |
| 1632 | AllocationResult allocation; |
| 1633 | if (space_to_allocate_ == NEW_SPACE) { |
| 1634 | if (size > kMaxLabObjectSize) { |
| 1635 | allocation = |
| 1636 | AllocateInNewSpace(size, alignment, kNonstickyBailoutOldSpace); |
| 1637 | } else { |
| 1638 | allocation = AllocateInLab(size, alignment); |
| 1639 | } |
| 1640 | } |
| 1641 | if (allocation.IsRetry() || (space_to_allocate_ == OLD_SPACE)) { |
| 1642 | allocation = AllocateInOldSpace(size, alignment); |
| 1643 | } |
| 1644 | bool ok = allocation.To(target_object); |
| 1645 | DCHECK(ok); |
| 1646 | USE(ok); |
| 1647 | return space_to_allocate_; |
| 1648 | } |
| 1649 | |
| 1650 | inline bool NewLocalAllocationBuffer() { |
| 1651 | AllocationResult result = |
| 1652 | AllocateInNewSpace(kLabSize, kWordAligned, kStickyBailoutOldSpace); |
| 1653 | LocalAllocationBuffer saved_old_buffer = buffer_; |
| 1654 | buffer_ = LocalAllocationBuffer::FromResult(heap_, result, kLabSize); |
| 1655 | if (buffer_.IsValid()) { |
| 1656 | buffer_.TryMerge(&saved_old_buffer); |
| 1657 | return true; |
| 1658 | } |
| 1659 | return false; |
| 1660 | } |
| 1661 | |
| 1662 | inline AllocationResult AllocateInNewSpace(int size_in_bytes, |
| 1663 | AllocationAlignment alignment, |
| 1664 | NewSpaceAllocationMode mode) { |
| 1665 | AllocationResult allocation = |
| 1666 | heap_->new_space()->AllocateRawSynchronized(size_in_bytes, alignment); |
| 1667 | if (allocation.IsRetry()) { |
| 1668 | if (!heap_->new_space()->AddFreshPageSynchronized()) { |
| 1669 | if (mode == kStickyBailoutOldSpace) space_to_allocate_ = OLD_SPACE; |
| 1670 | } else { |
| 1671 | allocation = heap_->new_space()->AllocateRawSynchronized(size_in_bytes, |
| 1672 | alignment); |
| 1673 | if (allocation.IsRetry()) { |
| 1674 | if (mode == kStickyBailoutOldSpace) space_to_allocate_ = OLD_SPACE; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1675 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1676 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1677 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1678 | return allocation; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1679 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1680 | |
| 1681 | inline AllocationResult AllocateInOldSpace(int size_in_bytes, |
| 1682 | AllocationAlignment alignment) { |
| 1683 | AllocationResult allocation = |
| 1684 | heap_->old_space()->AllocateRaw(size_in_bytes, alignment); |
| 1685 | if (allocation.IsRetry()) { |
| 1686 | FatalProcessOutOfMemory( |
| 1687 | "MarkCompactCollector: semi-space copy, fallback in old gen\n"); |
| 1688 | } |
| 1689 | return allocation; |
| 1690 | } |
| 1691 | |
| 1692 | inline AllocationResult AllocateInLab(int size_in_bytes, |
| 1693 | AllocationAlignment alignment) { |
| 1694 | AllocationResult allocation; |
| 1695 | if (!buffer_.IsValid()) { |
| 1696 | if (!NewLocalAllocationBuffer()) { |
| 1697 | space_to_allocate_ = OLD_SPACE; |
| 1698 | return AllocationResult::Retry(OLD_SPACE); |
| 1699 | } |
| 1700 | } |
| 1701 | allocation = buffer_.AllocateRawAligned(size_in_bytes, alignment); |
| 1702 | if (allocation.IsRetry()) { |
| 1703 | if (!NewLocalAllocationBuffer()) { |
| 1704 | space_to_allocate_ = OLD_SPACE; |
| 1705 | return AllocationResult::Retry(OLD_SPACE); |
| 1706 | } else { |
| 1707 | allocation = buffer_.AllocateRawAligned(size_in_bytes, alignment); |
| 1708 | if (allocation.IsRetry()) { |
| 1709 | space_to_allocate_ = OLD_SPACE; |
| 1710 | return AllocationResult::Retry(OLD_SPACE); |
| 1711 | } |
| 1712 | } |
| 1713 | } |
| 1714 | return allocation; |
| 1715 | } |
| 1716 | |
| 1717 | LocalAllocationBuffer buffer_; |
| 1718 | AllocationSpace space_to_allocate_; |
| 1719 | intptr_t promoted_size_; |
| 1720 | intptr_t semispace_copied_size_; |
| 1721 | HashMap* local_pretenuring_feedback_; |
| 1722 | }; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1723 | |
| 1724 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1725 | class MarkCompactCollector::EvacuateOldSpaceVisitor final |
| 1726 | : public MarkCompactCollector::EvacuateVisitorBase { |
| 1727 | public: |
| 1728 | EvacuateOldSpaceVisitor(Heap* heap, |
| 1729 | CompactionSpaceCollection* compaction_spaces, |
| 1730 | SlotsBuffer** evacuation_slots_buffer) |
| 1731 | : EvacuateVisitorBase(heap, evacuation_slots_buffer), |
| 1732 | compaction_spaces_(compaction_spaces) {} |
| 1733 | |
| 1734 | bool Visit(HeapObject* object) override { |
| 1735 | CompactionSpace* target_space = compaction_spaces_->Get( |
| 1736 | Page::FromAddress(object->address())->owner()->identity()); |
| 1737 | HeapObject* target_object = nullptr; |
| 1738 | if (TryEvacuateObject(target_space, object, &target_object)) { |
| 1739 | DCHECK(object->map_word().IsForwardingAddress()); |
| 1740 | return true; |
| 1741 | } |
| 1742 | return false; |
| 1743 | } |
| 1744 | |
| 1745 | private: |
| 1746 | CompactionSpaceCollection* compaction_spaces_; |
| 1747 | }; |
| 1748 | |
| 1749 | |
| 1750 | void MarkCompactCollector::DiscoverGreyObjectsInSpace(PagedSpace* space) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1751 | PageIterator it(space); |
| 1752 | while (it.has_next()) { |
| 1753 | Page* p = it.next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1754 | DiscoverGreyObjectsOnPage(p); |
| 1755 | if (marking_deque()->IsFull()) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1756 | } |
| 1757 | } |
| 1758 | |
| 1759 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1760 | void MarkCompactCollector::DiscoverGreyObjectsInNewSpace() { |
| 1761 | NewSpace* space = heap()->new_space(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1762 | NewSpacePageIterator it(space->bottom(), space->top()); |
| 1763 | while (it.has_next()) { |
| 1764 | NewSpacePage* page = it.next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1765 | DiscoverGreyObjectsOnPage(page); |
| 1766 | if (marking_deque()->IsFull()) return; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1767 | } |
| 1768 | } |
| 1769 | |
| 1770 | |
| 1771 | bool MarkCompactCollector::IsUnmarkedHeapObject(Object** p) { |
| 1772 | Object* o = *p; |
| 1773 | if (!o->IsHeapObject()) return false; |
| 1774 | HeapObject* heap_object = HeapObject::cast(o); |
| 1775 | MarkBit mark = Marking::MarkBitFrom(heap_object); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1776 | return Marking::IsWhite(mark); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1777 | } |
| 1778 | |
| 1779 | |
| 1780 | bool MarkCompactCollector::IsUnmarkedHeapObjectWithHeap(Heap* heap, |
| 1781 | Object** p) { |
| 1782 | Object* o = *p; |
| 1783 | DCHECK(o->IsHeapObject()); |
| 1784 | HeapObject* heap_object = HeapObject::cast(o); |
| 1785 | MarkBit mark = Marking::MarkBitFrom(heap_object); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1786 | return Marking::IsWhite(mark); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1787 | } |
| 1788 | |
| 1789 | |
| 1790 | void MarkCompactCollector::MarkStringTable(RootMarkingVisitor* visitor) { |
| 1791 | StringTable* string_table = heap()->string_table(); |
| 1792 | // Mark the string table itself. |
| 1793 | MarkBit string_table_mark = Marking::MarkBitFrom(string_table); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1794 | if (Marking::IsWhite(string_table_mark)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1795 | // String table could have already been marked by visiting the handles list. |
| 1796 | SetMark(string_table, string_table_mark); |
| 1797 | } |
| 1798 | // Explicitly mark the prefix. |
| 1799 | string_table->IteratePrefix(visitor); |
| 1800 | ProcessMarkingDeque(); |
| 1801 | } |
| 1802 | |
| 1803 | |
| 1804 | void MarkCompactCollector::MarkAllocationSite(AllocationSite* site) { |
| 1805 | MarkBit mark_bit = Marking::MarkBitFrom(site); |
| 1806 | SetMark(site, mark_bit); |
| 1807 | } |
| 1808 | |
| 1809 | |
| 1810 | void MarkCompactCollector::MarkRoots(RootMarkingVisitor* visitor) { |
| 1811 | // Mark the heap roots including global variables, stack variables, |
| 1812 | // etc., and all objects reachable from them. |
| 1813 | heap()->IterateStrongRoots(visitor, VISIT_ONLY_STRONG); |
| 1814 | |
| 1815 | // Handle the string table specially. |
| 1816 | MarkStringTable(visitor); |
| 1817 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1818 | // There may be overflowed objects in the heap. Visit them now. |
| 1819 | while (marking_deque_.overflowed()) { |
| 1820 | RefillMarkingDeque(); |
| 1821 | EmptyMarkingDeque(); |
| 1822 | } |
| 1823 | } |
| 1824 | |
| 1825 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1826 | void MarkCompactCollector::MarkImplicitRefGroups( |
| 1827 | MarkObjectFunction mark_object) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1828 | List<ImplicitRefGroup*>* ref_groups = |
| 1829 | isolate()->global_handles()->implicit_ref_groups(); |
| 1830 | |
| 1831 | int last = 0; |
| 1832 | for (int i = 0; i < ref_groups->length(); i++) { |
| 1833 | ImplicitRefGroup* entry = ref_groups->at(i); |
| 1834 | DCHECK(entry != NULL); |
| 1835 | |
| 1836 | if (!IsMarked(*entry->parent)) { |
| 1837 | (*ref_groups)[last++] = entry; |
| 1838 | continue; |
| 1839 | } |
| 1840 | |
| 1841 | Object*** children = entry->children; |
| 1842 | // A parent object is marked, so mark all child heap objects. |
| 1843 | for (size_t j = 0; j < entry->length; ++j) { |
| 1844 | if ((*children[j])->IsHeapObject()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1845 | mark_object(heap(), HeapObject::cast(*children[j])); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1846 | } |
| 1847 | } |
| 1848 | |
| 1849 | // Once the entire group has been marked, dispose it because it's |
| 1850 | // not needed anymore. |
| 1851 | delete entry; |
| 1852 | } |
| 1853 | ref_groups->Rewind(last); |
| 1854 | } |
| 1855 | |
| 1856 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1857 | // Mark all objects reachable from the objects on the marking stack. |
| 1858 | // Before: the marking stack contains zero or more heap object pointers. |
| 1859 | // After: the marking stack is empty, and all objects reachable from the |
| 1860 | // marking stack have been marked, or are overflowed in the heap. |
| 1861 | void MarkCompactCollector::EmptyMarkingDeque() { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1862 | Map* filler_map = heap_->one_pointer_filler_map(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1863 | while (!marking_deque_.IsEmpty()) { |
| 1864 | HeapObject* object = marking_deque_.Pop(); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1865 | // Explicitly skip one word fillers. Incremental markbit patterns are |
| 1866 | // correct only for objects that occupy at least two words. |
| 1867 | Map* map = object->map(); |
| 1868 | if (map == filler_map) continue; |
| 1869 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1870 | DCHECK(object->IsHeapObject()); |
| 1871 | DCHECK(heap()->Contains(object)); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1872 | DCHECK(!Marking::IsWhite(Marking::MarkBitFrom(object))); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1873 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1874 | MarkBit map_mark = Marking::MarkBitFrom(map); |
| 1875 | MarkObject(map, map_mark); |
| 1876 | |
| 1877 | MarkCompactMarkingVisitor::IterateBody(map, object); |
| 1878 | } |
| 1879 | } |
| 1880 | |
| 1881 | |
| 1882 | // Sweep the heap for overflowed objects, clear their overflow bits, and |
| 1883 | // push them on the marking stack. Stop early if the marking stack fills |
| 1884 | // before sweeping completes. If sweeping completes, there are no remaining |
| 1885 | // overflowed objects in the heap so the overflow flag on the markings stack |
| 1886 | // is cleared. |
| 1887 | void MarkCompactCollector::RefillMarkingDeque() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1888 | isolate()->CountUsage(v8::Isolate::UseCounterFeature::kMarkDequeOverflow); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1889 | DCHECK(marking_deque_.overflowed()); |
| 1890 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1891 | DiscoverGreyObjectsInNewSpace(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1892 | if (marking_deque_.IsFull()) return; |
| 1893 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1894 | DiscoverGreyObjectsInSpace(heap()->old_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1895 | if (marking_deque_.IsFull()) return; |
| 1896 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1897 | DiscoverGreyObjectsInSpace(heap()->code_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1898 | if (marking_deque_.IsFull()) return; |
| 1899 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1900 | DiscoverGreyObjectsInSpace(heap()->map_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1901 | if (marking_deque_.IsFull()) return; |
| 1902 | |
| 1903 | LargeObjectIterator lo_it(heap()->lo_space()); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1904 | DiscoverGreyObjectsWithIterator(&lo_it); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1905 | if (marking_deque_.IsFull()) return; |
| 1906 | |
| 1907 | marking_deque_.ClearOverflowed(); |
| 1908 | } |
| 1909 | |
| 1910 | |
| 1911 | // Mark all objects reachable (transitively) from objects on the marking |
| 1912 | // stack. Before: the marking stack contains zero or more heap object |
| 1913 | // pointers. After: the marking stack is empty and there are no overflowed |
| 1914 | // objects in the heap. |
| 1915 | void MarkCompactCollector::ProcessMarkingDeque() { |
| 1916 | EmptyMarkingDeque(); |
| 1917 | while (marking_deque_.overflowed()) { |
| 1918 | RefillMarkingDeque(); |
| 1919 | EmptyMarkingDeque(); |
| 1920 | } |
| 1921 | } |
| 1922 | |
| 1923 | |
| 1924 | // Mark all objects reachable (transitively) from objects on the marking |
| 1925 | // stack including references only considered in the atomic marking pause. |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1926 | void MarkCompactCollector::ProcessEphemeralMarking( |
| 1927 | ObjectVisitor* visitor, bool only_process_harmony_weak_collections) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1928 | bool work_to_do = true; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1929 | DCHECK(marking_deque_.IsEmpty() && !marking_deque_.overflowed()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1930 | while (work_to_do) { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1931 | if (!only_process_harmony_weak_collections) { |
| 1932 | isolate()->global_handles()->IterateObjectGroups( |
| 1933 | visitor, &IsUnmarkedHeapObjectWithHeap); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1934 | MarkImplicitRefGroups(&MarkCompactMarkingVisitor::MarkObject); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1935 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1936 | ProcessWeakCollections(); |
| 1937 | work_to_do = !marking_deque_.IsEmpty(); |
| 1938 | ProcessMarkingDeque(); |
| 1939 | } |
| 1940 | } |
| 1941 | |
| 1942 | |
| 1943 | void MarkCompactCollector::ProcessTopOptimizedFrame(ObjectVisitor* visitor) { |
| 1944 | for (StackFrameIterator it(isolate(), isolate()->thread_local_top()); |
| 1945 | !it.done(); it.Advance()) { |
| 1946 | if (it.frame()->type() == StackFrame::JAVA_SCRIPT) { |
| 1947 | return; |
| 1948 | } |
| 1949 | if (it.frame()->type() == StackFrame::OPTIMIZED) { |
| 1950 | Code* code = it.frame()->LookupCode(); |
| 1951 | if (!code->CanDeoptAt(it.frame()->pc())) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1952 | Code::BodyDescriptor::IterateBody(code, visitor); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1953 | } |
| 1954 | ProcessMarkingDeque(); |
| 1955 | return; |
| 1956 | } |
| 1957 | } |
| 1958 | } |
| 1959 | |
| 1960 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1961 | void MarkCompactCollector::EnsureMarkingDequeIsReserved() { |
| 1962 | DCHECK(!marking_deque_.in_use()); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1963 | if (marking_deque_memory_ == NULL) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1964 | marking_deque_memory_ = new base::VirtualMemory(kMaxMarkingDequeSize); |
| 1965 | marking_deque_memory_committed_ = 0; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1966 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1967 | if (marking_deque_memory_ == NULL) { |
| 1968 | V8::FatalProcessOutOfMemory("EnsureMarkingDequeIsReserved"); |
| 1969 | } |
| 1970 | } |
| 1971 | |
| 1972 | |
| 1973 | void MarkCompactCollector::EnsureMarkingDequeIsCommitted(size_t max_size) { |
| 1974 | // If the marking deque is too small, we try to allocate a bigger one. |
| 1975 | // If that fails, make do with a smaller one. |
| 1976 | CHECK(!marking_deque_.in_use()); |
| 1977 | for (size_t size = max_size; size >= kMinMarkingDequeSize; size >>= 1) { |
| 1978 | base::VirtualMemory* memory = marking_deque_memory_; |
| 1979 | size_t currently_committed = marking_deque_memory_committed_; |
| 1980 | |
| 1981 | if (currently_committed == size) return; |
| 1982 | |
| 1983 | if (currently_committed > size) { |
| 1984 | bool success = marking_deque_memory_->Uncommit( |
| 1985 | reinterpret_cast<Address>(marking_deque_memory_->address()) + size, |
| 1986 | currently_committed - size); |
| 1987 | if (success) { |
| 1988 | marking_deque_memory_committed_ = size; |
| 1989 | return; |
| 1990 | } |
| 1991 | UNREACHABLE(); |
| 1992 | } |
| 1993 | |
| 1994 | bool success = memory->Commit( |
| 1995 | reinterpret_cast<Address>(memory->address()) + currently_committed, |
| 1996 | size - currently_committed, |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1997 | false); // Not executable. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1998 | if (success) { |
| 1999 | marking_deque_memory_committed_ = size; |
| 2000 | return; |
| 2001 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2002 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2003 | V8::FatalProcessOutOfMemory("EnsureMarkingDequeIsCommitted"); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2004 | } |
| 2005 | |
| 2006 | |
| 2007 | void MarkCompactCollector::InitializeMarkingDeque() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2008 | DCHECK(!marking_deque_.in_use()); |
| 2009 | DCHECK(marking_deque_memory_committed_ > 0); |
| 2010 | Address addr = static_cast<Address>(marking_deque_memory_->address()); |
| 2011 | size_t size = marking_deque_memory_committed_; |
| 2012 | if (FLAG_force_marking_deque_overflows) size = 64 * kPointerSize; |
| 2013 | marking_deque_.Initialize(addr, addr + size); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2014 | } |
| 2015 | |
| 2016 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2017 | void MarkingDeque::Initialize(Address low, Address high) { |
| 2018 | DCHECK(!in_use_); |
| 2019 | HeapObject** obj_low = reinterpret_cast<HeapObject**>(low); |
| 2020 | HeapObject** obj_high = reinterpret_cast<HeapObject**>(high); |
| 2021 | array_ = obj_low; |
| 2022 | mask_ = base::bits::RoundDownToPowerOfTwo32( |
| 2023 | static_cast<uint32_t>(obj_high - obj_low)) - |
| 2024 | 1; |
| 2025 | top_ = bottom_ = 0; |
| 2026 | overflowed_ = false; |
| 2027 | in_use_ = true; |
| 2028 | } |
| 2029 | |
| 2030 | |
| 2031 | void MarkingDeque::Uninitialize(bool aborting) { |
| 2032 | if (!aborting) { |
| 2033 | DCHECK(IsEmpty()); |
| 2034 | DCHECK(!overflowed_); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2035 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2036 | DCHECK(in_use_); |
| 2037 | top_ = bottom_ = 0xdecbad; |
| 2038 | in_use_ = false; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2039 | } |
| 2040 | |
| 2041 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2042 | void MarkCompactCollector::MarkLiveObjects() { |
| 2043 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_MARK); |
| 2044 | double start_time = 0.0; |
| 2045 | if (FLAG_print_cumulative_gc_stat) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2046 | start_time = heap_->MonotonicallyIncreasingTimeInMs(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2047 | } |
| 2048 | // The recursive GC marker detects when it is nearing stack overflow, |
| 2049 | // and switches to a different marking system. JS interrupts interfere |
| 2050 | // with the C stack limit check. |
| 2051 | PostponeInterruptsScope postpone(isolate()); |
| 2052 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2053 | { |
| 2054 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2055 | GCTracer::Scope::MC_MARK_FINISH_INCREMENTAL); |
| 2056 | IncrementalMarking* incremental_marking = heap_->incremental_marking(); |
| 2057 | if (was_marked_incrementally_) { |
| 2058 | incremental_marking->Finalize(); |
| 2059 | } else { |
| 2060 | // Abort any pending incremental activities e.g. incremental sweeping. |
| 2061 | incremental_marking->Stop(); |
| 2062 | if (marking_deque_.in_use()) { |
| 2063 | marking_deque_.Uninitialize(true); |
| 2064 | } |
| 2065 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2066 | } |
| 2067 | |
| 2068 | #ifdef DEBUG |
| 2069 | DCHECK(state_ == PREPARE_GC); |
| 2070 | state_ = MARK_LIVE_OBJECTS; |
| 2071 | #endif |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2072 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2073 | EnsureMarkingDequeIsCommittedAndInitialize( |
| 2074 | MarkCompactCollector::kMaxMarkingDequeSize); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2075 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2076 | { |
| 2077 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2078 | GCTracer::Scope::MC_MARK_PREPARE_CODE_FLUSH); |
| 2079 | PrepareForCodeFlushing(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2080 | } |
| 2081 | |
| 2082 | RootMarkingVisitor root_visitor(heap()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2083 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2084 | { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2085 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_MARK_ROOTS); |
| 2086 | MarkRoots(&root_visitor); |
| 2087 | ProcessTopOptimizedFrame(&root_visitor); |
| 2088 | } |
| 2089 | |
| 2090 | { |
| 2091 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2092 | GCTracer::Scope::MC_MARK_WEAK_CLOSURE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2093 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2094 | // The objects reachable from the roots are marked, yet unreachable |
| 2095 | // objects are unmarked. Mark objects reachable due to host |
| 2096 | // application specific logic or through Harmony weak maps. |
| 2097 | ProcessEphemeralMarking(&root_visitor, false); |
| 2098 | |
| 2099 | // The objects reachable from the roots, weak maps or object groups |
| 2100 | // are marked. Objects pointed to only by weak global handles cannot be |
| 2101 | // immediately reclaimed. Instead, we have to mark them as pending and mark |
| 2102 | // objects reachable from them. |
| 2103 | // |
| 2104 | // First we identify nonlive weak handles and mark them as pending |
| 2105 | // destruction. |
| 2106 | heap()->isolate()->global_handles()->IdentifyWeakHandles( |
| 2107 | &IsUnmarkedHeapObject); |
| 2108 | // Then we mark the objects. |
| 2109 | heap()->isolate()->global_handles()->IterateWeakRoots(&root_visitor); |
| 2110 | ProcessMarkingDeque(); |
| 2111 | |
| 2112 | // Repeat Harmony weak maps marking to mark unmarked objects reachable from |
| 2113 | // the weak roots we just marked as pending destruction. |
| 2114 | // |
| 2115 | // We only process harmony collections, as all object groups have been fully |
| 2116 | // processed and no weakly reachable node can discover new objects groups. |
| 2117 | ProcessEphemeralMarking(&root_visitor, true); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2118 | } |
| 2119 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2120 | if (FLAG_print_cumulative_gc_stat) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2121 | heap_->tracer()->AddMarkingTime(heap_->MonotonicallyIncreasingTimeInMs() - |
| 2122 | start_time); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2123 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2124 | if (FLAG_track_gc_object_stats) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2125 | if (FLAG_trace_gc_object_stats) { |
| 2126 | heap()->object_stats_->TraceObjectStats(); |
| 2127 | } |
| 2128 | heap()->object_stats_->CheckpointObjectStats(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2129 | } |
| 2130 | } |
| 2131 | |
| 2132 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2133 | void MarkCompactCollector::ClearNonLiveReferences() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2134 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_CLEAR); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2135 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2136 | { |
| 2137 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2138 | GCTracer::Scope::MC_CLEAR_STRING_TABLE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2139 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2140 | // Prune the string table removing all strings only pointed to by the |
| 2141 | // string table. Cannot use string_table() here because the string |
| 2142 | // table is marked. |
| 2143 | StringTable* string_table = heap()->string_table(); |
| 2144 | InternalizedStringTableCleaner internalized_visitor(heap()); |
| 2145 | string_table->IterateElements(&internalized_visitor); |
| 2146 | string_table->ElementsRemoved(internalized_visitor.PointersRemoved()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2147 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2148 | ExternalStringTableCleaner external_visitor(heap()); |
| 2149 | heap()->external_string_table_.Iterate(&external_visitor); |
| 2150 | heap()->external_string_table_.CleanUp(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2151 | } |
| 2152 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2153 | { |
| 2154 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2155 | GCTracer::Scope::MC_CLEAR_WEAK_LISTS); |
| 2156 | // Process the weak references. |
| 2157 | MarkCompactWeakObjectRetainer mark_compact_object_retainer; |
| 2158 | heap()->ProcessAllWeakReferences(&mark_compact_object_retainer); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2159 | } |
| 2160 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2161 | { |
| 2162 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2163 | GCTracer::Scope::MC_CLEAR_GLOBAL_HANDLES); |
| 2164 | |
| 2165 | // Remove object groups after marking phase. |
| 2166 | heap()->isolate()->global_handles()->RemoveObjectGroups(); |
| 2167 | heap()->isolate()->global_handles()->RemoveImplicitRefGroups(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2168 | } |
| 2169 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2170 | // Flush code from collected candidates. |
| 2171 | if (is_code_flushing_enabled()) { |
| 2172 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2173 | GCTracer::Scope::MC_CLEAR_CODE_FLUSH); |
| 2174 | code_flusher_->ProcessCandidates(); |
| 2175 | } |
| 2176 | |
| 2177 | |
| 2178 | DependentCode* dependent_code_list; |
| 2179 | Object* non_live_map_list; |
| 2180 | ClearWeakCells(&non_live_map_list, &dependent_code_list); |
| 2181 | |
| 2182 | { |
| 2183 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_CLEAR_MAPS); |
| 2184 | ClearSimpleMapTransitions(non_live_map_list); |
| 2185 | ClearFullMapTransitions(); |
| 2186 | } |
| 2187 | |
| 2188 | MarkDependentCodeForDeoptimization(dependent_code_list); |
| 2189 | |
| 2190 | ClearWeakCollections(); |
| 2191 | |
| 2192 | ClearInvalidStoreAndSlotsBufferEntries(); |
| 2193 | } |
| 2194 | |
| 2195 | |
| 2196 | void MarkCompactCollector::MarkDependentCodeForDeoptimization( |
| 2197 | DependentCode* list_head) { |
| 2198 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 2199 | GCTracer::Scope::MC_CLEAR_DEPENDENT_CODE); |
| 2200 | Isolate* isolate = this->isolate(); |
| 2201 | DependentCode* current = list_head; |
| 2202 | while (current->length() > 0) { |
| 2203 | have_code_to_deoptimize_ |= current->MarkCodeForDeoptimization( |
| 2204 | isolate, DependentCode::kWeakCodeGroup); |
| 2205 | current = current->next_link(); |
| 2206 | } |
| 2207 | |
| 2208 | WeakHashTable* table = heap_->weak_object_to_code_table(); |
| 2209 | uint32_t capacity = table->Capacity(); |
| 2210 | for (uint32_t i = 0; i < capacity; i++) { |
| 2211 | uint32_t key_index = table->EntryToIndex(i); |
| 2212 | Object* key = table->get(key_index); |
| 2213 | if (!table->IsKey(key)) continue; |
| 2214 | uint32_t value_index = table->EntryToValueIndex(i); |
| 2215 | Object* value = table->get(value_index); |
| 2216 | DCHECK(key->IsWeakCell()); |
| 2217 | if (WeakCell::cast(key)->cleared()) { |
| 2218 | have_code_to_deoptimize_ |= |
| 2219 | DependentCode::cast(value)->MarkCodeForDeoptimization( |
| 2220 | isolate, DependentCode::kWeakCodeGroup); |
| 2221 | table->set(key_index, heap_->the_hole_value()); |
| 2222 | table->set(value_index, heap_->the_hole_value()); |
| 2223 | table->ElementRemoved(); |
| 2224 | } |
| 2225 | } |
| 2226 | } |
| 2227 | |
| 2228 | |
| 2229 | void MarkCompactCollector::ClearSimpleMapTransitions( |
| 2230 | Object* non_live_map_list) { |
| 2231 | Object* the_hole_value = heap()->the_hole_value(); |
| 2232 | Object* weak_cell_obj = non_live_map_list; |
| 2233 | while (weak_cell_obj != Smi::FromInt(0)) { |
| 2234 | WeakCell* weak_cell = WeakCell::cast(weak_cell_obj); |
| 2235 | Map* map = Map::cast(weak_cell->value()); |
| 2236 | DCHECK(Marking::IsWhite(Marking::MarkBitFrom(map))); |
| 2237 | Object* potential_parent = map->constructor_or_backpointer(); |
| 2238 | if (potential_parent->IsMap()) { |
| 2239 | Map* parent = Map::cast(potential_parent); |
| 2240 | if (Marking::IsBlackOrGrey(Marking::MarkBitFrom(parent)) && |
| 2241 | parent->raw_transitions() == weak_cell) { |
| 2242 | ClearSimpleMapTransition(parent, map); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2243 | } |
| 2244 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2245 | weak_cell->clear(); |
| 2246 | weak_cell_obj = weak_cell->next(); |
| 2247 | weak_cell->clear_next(the_hole_value); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2248 | } |
| 2249 | } |
| 2250 | |
| 2251 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2252 | void MarkCompactCollector::ClearSimpleMapTransition(Map* map, |
| 2253 | Map* dead_transition) { |
| 2254 | // A previously existing simple transition (stored in a WeakCell) is going |
| 2255 | // to be cleared. Clear the useless cell pointer, and take ownership |
| 2256 | // of the descriptor array. |
| 2257 | map->set_raw_transitions(Smi::FromInt(0)); |
| 2258 | int number_of_own_descriptors = map->NumberOfOwnDescriptors(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2259 | DescriptorArray* descriptors = map->instance_descriptors(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2260 | if (descriptors == dead_transition->instance_descriptors() && |
| 2261 | number_of_own_descriptors > 0) { |
| 2262 | TrimDescriptorArray(map, descriptors); |
| 2263 | DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors); |
| 2264 | map->set_owns_descriptors(true); |
| 2265 | } |
| 2266 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2267 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2268 | |
| 2269 | void MarkCompactCollector::ClearFullMapTransitions() { |
| 2270 | HeapObject* undefined = heap()->undefined_value(); |
| 2271 | Object* obj = heap()->encountered_transition_arrays(); |
| 2272 | while (obj != Smi::FromInt(0)) { |
| 2273 | TransitionArray* array = TransitionArray::cast(obj); |
| 2274 | int num_transitions = array->number_of_entries(); |
| 2275 | DCHECK_EQ(TransitionArray::NumberOfTransitions(array), num_transitions); |
| 2276 | if (num_transitions > 0) { |
| 2277 | Map* map = array->GetTarget(0); |
| 2278 | Map* parent = Map::cast(map->constructor_or_backpointer()); |
| 2279 | bool parent_is_alive = |
| 2280 | Marking::IsBlackOrGrey(Marking::MarkBitFrom(parent)); |
| 2281 | DescriptorArray* descriptors = |
| 2282 | parent_is_alive ? parent->instance_descriptors() : nullptr; |
| 2283 | bool descriptors_owner_died = |
| 2284 | CompactTransitionArray(parent, array, descriptors); |
| 2285 | if (descriptors_owner_died) { |
| 2286 | TrimDescriptorArray(parent, descriptors); |
| 2287 | } |
| 2288 | } |
| 2289 | obj = array->next_link(); |
| 2290 | array->set_next_link(undefined, SKIP_WRITE_BARRIER); |
| 2291 | } |
| 2292 | heap()->set_encountered_transition_arrays(Smi::FromInt(0)); |
| 2293 | } |
| 2294 | |
| 2295 | |
| 2296 | bool MarkCompactCollector::CompactTransitionArray( |
| 2297 | Map* map, TransitionArray* transitions, DescriptorArray* descriptors) { |
| 2298 | int num_transitions = transitions->number_of_entries(); |
| 2299 | bool descriptors_owner_died = false; |
| 2300 | int transition_index = 0; |
| 2301 | // Compact all live transitions to the left. |
| 2302 | for (int i = 0; i < num_transitions; ++i) { |
| 2303 | Map* target = transitions->GetTarget(i); |
| 2304 | DCHECK_EQ(target->constructor_or_backpointer(), map); |
| 2305 | if (Marking::IsWhite(Marking::MarkBitFrom(target))) { |
| 2306 | if (descriptors != nullptr && |
| 2307 | target->instance_descriptors() == descriptors) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2308 | descriptors_owner_died = true; |
| 2309 | } |
| 2310 | } else { |
| 2311 | if (i != transition_index) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2312 | Name* key = transitions->GetKey(i); |
| 2313 | transitions->SetKey(transition_index, key); |
| 2314 | Object** key_slot = transitions->GetKeySlot(transition_index); |
| 2315 | RecordSlot(transitions, key_slot, key); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2316 | // Target slots do not need to be recorded since maps are not compacted. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2317 | transitions->SetTarget(transition_index, transitions->GetTarget(i)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2318 | } |
| 2319 | transition_index++; |
| 2320 | } |
| 2321 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2322 | // If there are no transitions to be cleared, return. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2323 | if (transition_index == num_transitions) { |
| 2324 | DCHECK(!descriptors_owner_died); |
| 2325 | return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2326 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2327 | // Note that we never eliminate a transition array, though we might right-trim |
| 2328 | // such that number_of_transitions() == 0. If this assumption changes, |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2329 | // TransitionArray::Insert() will need to deal with the case that a transition |
| 2330 | // array disappeared during GC. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2331 | int trim = TransitionArray::Capacity(transitions) - transition_index; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2332 | if (trim > 0) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2333 | heap_->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>( |
| 2334 | transitions, trim * TransitionArray::kTransitionSize); |
| 2335 | transitions->SetNumberOfTransitions(transition_index); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2336 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2337 | return descriptors_owner_died; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2338 | } |
| 2339 | |
| 2340 | |
| 2341 | void MarkCompactCollector::TrimDescriptorArray(Map* map, |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2342 | DescriptorArray* descriptors) { |
| 2343 | int number_of_own_descriptors = map->NumberOfOwnDescriptors(); |
| 2344 | if (number_of_own_descriptors == 0) { |
| 2345 | DCHECK(descriptors == heap_->empty_descriptor_array()); |
| 2346 | return; |
| 2347 | } |
| 2348 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2349 | int number_of_descriptors = descriptors->number_of_descriptors_storage(); |
| 2350 | int to_trim = number_of_descriptors - number_of_own_descriptors; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2351 | if (to_trim > 0) { |
| 2352 | heap_->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>( |
| 2353 | descriptors, to_trim * DescriptorArray::kDescriptorSize); |
| 2354 | descriptors->SetNumberOfDescriptors(number_of_own_descriptors); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2355 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2356 | if (descriptors->HasEnumCache()) TrimEnumCache(map, descriptors); |
| 2357 | descriptors->Sort(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2358 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2359 | if (FLAG_unbox_double_fields) { |
| 2360 | LayoutDescriptor* layout_descriptor = map->layout_descriptor(); |
| 2361 | layout_descriptor = layout_descriptor->Trim(heap_, map, descriptors, |
| 2362 | number_of_own_descriptors); |
| 2363 | SLOW_DCHECK(layout_descriptor->IsConsistentWithMap(map, true)); |
| 2364 | } |
| 2365 | } |
| 2366 | DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors); |
| 2367 | map->set_owns_descriptors(true); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2368 | } |
| 2369 | |
| 2370 | |
| 2371 | void MarkCompactCollector::TrimEnumCache(Map* map, |
| 2372 | DescriptorArray* descriptors) { |
| 2373 | int live_enum = map->EnumLength(); |
| 2374 | if (live_enum == kInvalidEnumCacheSentinel) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2375 | live_enum = |
| 2376 | map->NumberOfDescribedProperties(OWN_DESCRIPTORS, ENUMERABLE_STRINGS); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2377 | } |
| 2378 | if (live_enum == 0) return descriptors->ClearEnumCache(); |
| 2379 | |
| 2380 | FixedArray* enum_cache = descriptors->GetEnumCache(); |
| 2381 | |
| 2382 | int to_trim = enum_cache->length() - live_enum; |
| 2383 | if (to_trim <= 0) return; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2384 | heap_->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>( |
| 2385 | descriptors->GetEnumCache(), to_trim); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2386 | |
| 2387 | if (!descriptors->HasEnumIndicesCache()) return; |
| 2388 | FixedArray* enum_indices_cache = descriptors->GetEnumIndicesCache(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2389 | heap_->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(enum_indices_cache, |
| 2390 | to_trim); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2391 | } |
| 2392 | |
| 2393 | |
| 2394 | void MarkCompactCollector::ProcessWeakCollections() { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2395 | Object* weak_collection_obj = heap()->encountered_weak_collections(); |
| 2396 | while (weak_collection_obj != Smi::FromInt(0)) { |
| 2397 | JSWeakCollection* weak_collection = |
| 2398 | reinterpret_cast<JSWeakCollection*>(weak_collection_obj); |
| 2399 | DCHECK(MarkCompactCollector::IsMarked(weak_collection)); |
| 2400 | if (weak_collection->table()->IsHashTable()) { |
| 2401 | ObjectHashTable* table = ObjectHashTable::cast(weak_collection->table()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2402 | for (int i = 0; i < table->Capacity(); i++) { |
| 2403 | if (MarkCompactCollector::IsMarked(HeapObject::cast(table->KeyAt(i)))) { |
| 2404 | Object** key_slot = |
| 2405 | table->RawFieldOfElementAt(ObjectHashTable::EntryToIndex(i)); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2406 | RecordSlot(table, key_slot, *key_slot); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2407 | Object** value_slot = |
| 2408 | table->RawFieldOfElementAt(ObjectHashTable::EntryToValueIndex(i)); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2409 | MarkCompactMarkingVisitor::MarkObjectByPointer(this, table, |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2410 | value_slot); |
| 2411 | } |
| 2412 | } |
| 2413 | } |
| 2414 | weak_collection_obj = weak_collection->next(); |
| 2415 | } |
| 2416 | } |
| 2417 | |
| 2418 | |
| 2419 | void MarkCompactCollector::ClearWeakCollections() { |
| 2420 | GCTracer::Scope gc_scope(heap()->tracer(), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2421 | GCTracer::Scope::MC_CLEAR_WEAK_COLLECTIONS); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2422 | Object* weak_collection_obj = heap()->encountered_weak_collections(); |
| 2423 | while (weak_collection_obj != Smi::FromInt(0)) { |
| 2424 | JSWeakCollection* weak_collection = |
| 2425 | reinterpret_cast<JSWeakCollection*>(weak_collection_obj); |
| 2426 | DCHECK(MarkCompactCollector::IsMarked(weak_collection)); |
| 2427 | if (weak_collection->table()->IsHashTable()) { |
| 2428 | ObjectHashTable* table = ObjectHashTable::cast(weak_collection->table()); |
| 2429 | for (int i = 0; i < table->Capacity(); i++) { |
| 2430 | HeapObject* key = HeapObject::cast(table->KeyAt(i)); |
| 2431 | if (!MarkCompactCollector::IsMarked(key)) { |
| 2432 | table->RemoveEntry(i); |
| 2433 | } |
| 2434 | } |
| 2435 | } |
| 2436 | weak_collection_obj = weak_collection->next(); |
| 2437 | weak_collection->set_next(heap()->undefined_value()); |
| 2438 | } |
| 2439 | heap()->set_encountered_weak_collections(Smi::FromInt(0)); |
| 2440 | } |
| 2441 | |
| 2442 | |
| 2443 | void MarkCompactCollector::AbortWeakCollections() { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2444 | Object* weak_collection_obj = heap()->encountered_weak_collections(); |
| 2445 | while (weak_collection_obj != Smi::FromInt(0)) { |
| 2446 | JSWeakCollection* weak_collection = |
| 2447 | reinterpret_cast<JSWeakCollection*>(weak_collection_obj); |
| 2448 | weak_collection_obj = weak_collection->next(); |
| 2449 | weak_collection->set_next(heap()->undefined_value()); |
| 2450 | } |
| 2451 | heap()->set_encountered_weak_collections(Smi::FromInt(0)); |
| 2452 | } |
| 2453 | |
| 2454 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2455 | void MarkCompactCollector::ClearWeakCells(Object** non_live_map_list, |
| 2456 | DependentCode** dependent_code_list) { |
| 2457 | Heap* heap = this->heap(); |
| 2458 | GCTracer::Scope gc_scope(heap->tracer(), |
| 2459 | GCTracer::Scope::MC_CLEAR_WEAK_CELLS); |
| 2460 | Object* weak_cell_obj = heap->encountered_weak_cells(); |
| 2461 | Object* the_hole_value = heap->the_hole_value(); |
| 2462 | DependentCode* dependent_code_head = |
| 2463 | DependentCode::cast(heap->empty_fixed_array()); |
| 2464 | Object* non_live_map_head = Smi::FromInt(0); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2465 | while (weak_cell_obj != Smi::FromInt(0)) { |
| 2466 | WeakCell* weak_cell = reinterpret_cast<WeakCell*>(weak_cell_obj); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2467 | Object* next_weak_cell = weak_cell->next(); |
| 2468 | bool clear_value = true; |
| 2469 | bool clear_next = true; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2470 | // We do not insert cleared weak cells into the list, so the value |
| 2471 | // cannot be a Smi here. |
| 2472 | HeapObject* value = HeapObject::cast(weak_cell->value()); |
| 2473 | if (!MarkCompactCollector::IsMarked(value)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2474 | // Cells for new-space objects embedded in optimized code are wrapped in |
| 2475 | // WeakCell and put into Heap::weak_object_to_code_table. |
| 2476 | // Such cells do not have any strong references but we want to keep them |
| 2477 | // alive as long as the cell value is alive. |
| 2478 | // TODO(ulan): remove this once we remove Heap::weak_object_to_code_table. |
| 2479 | if (value->IsCell()) { |
| 2480 | Object* cell_value = Cell::cast(value)->value(); |
| 2481 | if (cell_value->IsHeapObject() && |
| 2482 | MarkCompactCollector::IsMarked(HeapObject::cast(cell_value))) { |
| 2483 | // Resurrect the cell. |
| 2484 | MarkBit mark = Marking::MarkBitFrom(value); |
| 2485 | SetMark(value, mark); |
| 2486 | Object** slot = HeapObject::RawField(value, Cell::kValueOffset); |
| 2487 | RecordSlot(value, slot, *slot); |
| 2488 | slot = HeapObject::RawField(weak_cell, WeakCell::kValueOffset); |
| 2489 | RecordSlot(weak_cell, slot, *slot); |
| 2490 | clear_value = false; |
| 2491 | } |
| 2492 | } |
| 2493 | if (value->IsMap()) { |
| 2494 | // The map is non-live. |
| 2495 | Map* map = Map::cast(value); |
| 2496 | // Add dependent code to the dependent_code_list. |
| 2497 | DependentCode* candidate = map->dependent_code(); |
| 2498 | // We rely on the fact that the weak code group comes first. |
| 2499 | STATIC_ASSERT(DependentCode::kWeakCodeGroup == 0); |
| 2500 | if (candidate->length() > 0 && |
| 2501 | candidate->group() == DependentCode::kWeakCodeGroup) { |
| 2502 | candidate->set_next_link(dependent_code_head); |
| 2503 | dependent_code_head = candidate; |
| 2504 | } |
| 2505 | // Add the weak cell to the non_live_map list. |
| 2506 | weak_cell->set_next(non_live_map_head); |
| 2507 | non_live_map_head = weak_cell; |
| 2508 | clear_value = false; |
| 2509 | clear_next = false; |
| 2510 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2511 | } else { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2512 | // The value of the weak cell is alive. |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2513 | Object** slot = HeapObject::RawField(weak_cell, WeakCell::kValueOffset); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2514 | RecordSlot(weak_cell, slot, *slot); |
| 2515 | clear_value = false; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2516 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2517 | if (clear_value) { |
| 2518 | weak_cell->clear(); |
| 2519 | } |
| 2520 | if (clear_next) { |
| 2521 | weak_cell->clear_next(the_hole_value); |
| 2522 | } |
| 2523 | weak_cell_obj = next_weak_cell; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2524 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2525 | heap->set_encountered_weak_cells(Smi::FromInt(0)); |
| 2526 | *non_live_map_list = non_live_map_head; |
| 2527 | *dependent_code_list = dependent_code_head; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2528 | } |
| 2529 | |
| 2530 | |
| 2531 | void MarkCompactCollector::AbortWeakCells() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2532 | Object* the_hole_value = heap()->the_hole_value(); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2533 | Object* weak_cell_obj = heap()->encountered_weak_cells(); |
| 2534 | while (weak_cell_obj != Smi::FromInt(0)) { |
| 2535 | WeakCell* weak_cell = reinterpret_cast<WeakCell*>(weak_cell_obj); |
| 2536 | weak_cell_obj = weak_cell->next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2537 | weak_cell->clear_next(the_hole_value); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2538 | } |
| 2539 | heap()->set_encountered_weak_cells(Smi::FromInt(0)); |
| 2540 | } |
| 2541 | |
| 2542 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2543 | void MarkCompactCollector::AbortTransitionArrays() { |
| 2544 | HeapObject* undefined = heap()->undefined_value(); |
| 2545 | Object* obj = heap()->encountered_transition_arrays(); |
| 2546 | while (obj != Smi::FromInt(0)) { |
| 2547 | TransitionArray* array = TransitionArray::cast(obj); |
| 2548 | obj = array->next_link(); |
| 2549 | array->set_next_link(undefined, SKIP_WRITE_BARRIER); |
| 2550 | } |
| 2551 | heap()->set_encountered_transition_arrays(Smi::FromInt(0)); |
| 2552 | } |
| 2553 | |
| 2554 | |
| 2555 | void MarkCompactCollector::RecordMigratedSlot( |
| 2556 | Object* value, Address slot, SlotsBuffer** evacuation_slots_buffer) { |
| 2557 | // When parallel compaction is in progress, store and slots buffer entries |
| 2558 | // require synchronization. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2559 | if (heap_->InNewSpace(value)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2560 | if (compaction_in_progress_) { |
| 2561 | heap_->store_buffer()->MarkSynchronized(slot); |
| 2562 | } else { |
| 2563 | heap_->store_buffer()->Mark(slot); |
| 2564 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2565 | } else if (value->IsHeapObject() && IsOnEvacuationCandidate(value)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2566 | SlotsBuffer::AddTo(slots_buffer_allocator_, evacuation_slots_buffer, |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2567 | reinterpret_cast<Object**>(slot), |
| 2568 | SlotsBuffer::IGNORE_OVERFLOW); |
| 2569 | } |
| 2570 | } |
| 2571 | |
| 2572 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2573 | void MarkCompactCollector::RecordMigratedCodeEntrySlot( |
| 2574 | Address code_entry, Address code_entry_slot, |
| 2575 | SlotsBuffer** evacuation_slots_buffer) { |
| 2576 | if (Page::FromAddress(code_entry)->IsEvacuationCandidate()) { |
| 2577 | SlotsBuffer::AddTo(slots_buffer_allocator_, evacuation_slots_buffer, |
| 2578 | SlotsBuffer::CODE_ENTRY_SLOT, code_entry_slot, |
| 2579 | SlotsBuffer::IGNORE_OVERFLOW); |
| 2580 | } |
| 2581 | } |
| 2582 | |
| 2583 | |
| 2584 | void MarkCompactCollector::RecordMigratedCodeObjectSlot( |
| 2585 | Address code_object, SlotsBuffer** evacuation_slots_buffer) { |
| 2586 | SlotsBuffer::AddTo(slots_buffer_allocator_, evacuation_slots_buffer, |
| 2587 | SlotsBuffer::RELOCATED_CODE_OBJECT, code_object, |
| 2588 | SlotsBuffer::IGNORE_OVERFLOW); |
| 2589 | } |
| 2590 | |
| 2591 | |
| 2592 | static inline SlotsBuffer::SlotType SlotTypeForRMode(RelocInfo::Mode rmode) { |
| 2593 | if (RelocInfo::IsCodeTarget(rmode)) { |
| 2594 | return SlotsBuffer::CODE_TARGET_SLOT; |
| 2595 | } else if (RelocInfo::IsCell(rmode)) { |
| 2596 | return SlotsBuffer::CELL_TARGET_SLOT; |
| 2597 | } else if (RelocInfo::IsEmbeddedObject(rmode)) { |
| 2598 | return SlotsBuffer::EMBEDDED_OBJECT_SLOT; |
| 2599 | } else if (RelocInfo::IsDebugBreakSlot(rmode)) { |
| 2600 | return SlotsBuffer::DEBUG_TARGET_SLOT; |
| 2601 | } |
| 2602 | UNREACHABLE(); |
| 2603 | return SlotsBuffer::NUMBER_OF_SLOT_TYPES; |
| 2604 | } |
| 2605 | |
| 2606 | |
| 2607 | static inline SlotsBuffer::SlotType DecodeSlotType( |
| 2608 | SlotsBuffer::ObjectSlot slot) { |
| 2609 | return static_cast<SlotsBuffer::SlotType>(reinterpret_cast<intptr_t>(slot)); |
| 2610 | } |
| 2611 | |
| 2612 | |
| 2613 | void MarkCompactCollector::RecordRelocSlot(RelocInfo* rinfo, Object* target) { |
| 2614 | Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target)); |
| 2615 | RelocInfo::Mode rmode = rinfo->rmode(); |
| 2616 | if (target_page->IsEvacuationCandidate() && |
| 2617 | (rinfo->host() == NULL || |
| 2618 | !ShouldSkipEvacuationSlotRecording(rinfo->host()))) { |
| 2619 | Address addr = rinfo->pc(); |
| 2620 | SlotsBuffer::SlotType slot_type = SlotTypeForRMode(rmode); |
| 2621 | if (rinfo->IsInConstantPool()) { |
| 2622 | addr = rinfo->constant_pool_entry_address(); |
| 2623 | if (RelocInfo::IsCodeTarget(rmode)) { |
| 2624 | slot_type = SlotsBuffer::CODE_ENTRY_SLOT; |
| 2625 | } else { |
| 2626 | DCHECK(RelocInfo::IsEmbeddedObject(rmode)); |
| 2627 | slot_type = SlotsBuffer::OBJECT_SLOT; |
| 2628 | } |
| 2629 | } |
| 2630 | bool success = SlotsBuffer::AddTo( |
| 2631 | slots_buffer_allocator_, target_page->slots_buffer_address(), slot_type, |
| 2632 | addr, SlotsBuffer::FAIL_ON_OVERFLOW); |
| 2633 | if (!success) { |
| 2634 | EvictPopularEvacuationCandidate(target_page); |
| 2635 | } |
| 2636 | } |
| 2637 | } |
| 2638 | |
| 2639 | |
| 2640 | class RecordMigratedSlotVisitor final : public ObjectVisitor { |
| 2641 | public: |
| 2642 | RecordMigratedSlotVisitor(MarkCompactCollector* collector, |
| 2643 | SlotsBuffer** evacuation_slots_buffer) |
| 2644 | : collector_(collector), |
| 2645 | evacuation_slots_buffer_(evacuation_slots_buffer) {} |
| 2646 | |
| 2647 | V8_INLINE void VisitPointer(Object** p) override { |
| 2648 | collector_->RecordMigratedSlot(*p, reinterpret_cast<Address>(p), |
| 2649 | evacuation_slots_buffer_); |
| 2650 | } |
| 2651 | |
| 2652 | V8_INLINE void VisitPointers(Object** start, Object** end) override { |
| 2653 | while (start < end) { |
| 2654 | collector_->RecordMigratedSlot(*start, reinterpret_cast<Address>(start), |
| 2655 | evacuation_slots_buffer_); |
| 2656 | ++start; |
| 2657 | } |
| 2658 | } |
| 2659 | |
| 2660 | V8_INLINE void VisitCodeEntry(Address code_entry_slot) override { |
| 2661 | if (collector_->compacting_) { |
| 2662 | Address code_entry = Memory::Address_at(code_entry_slot); |
| 2663 | collector_->RecordMigratedCodeEntrySlot(code_entry, code_entry_slot, |
| 2664 | evacuation_slots_buffer_); |
| 2665 | } |
| 2666 | } |
| 2667 | |
| 2668 | private: |
| 2669 | MarkCompactCollector* collector_; |
| 2670 | SlotsBuffer** evacuation_slots_buffer_; |
| 2671 | }; |
| 2672 | |
| 2673 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2674 | // We scavenge new space simultaneously with sweeping. This is done in two |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2675 | // passes. |
| 2676 | // |
| 2677 | // The first pass migrates all alive objects from one semispace to another or |
| 2678 | // promotes them to old space. Forwarding address is written directly into |
| 2679 | // first word of object without any encoding. If object is dead we write |
| 2680 | // NULL as a forwarding address. |
| 2681 | // |
| 2682 | // The second pass updates pointers to new space in all spaces. It is possible |
| 2683 | // to encounter pointers to dead new space objects during traversal of pointers |
| 2684 | // to new space. We should clear them to avoid encountering them during next |
| 2685 | // pointer iteration. This is an issue if the store buffer overflows and we |
| 2686 | // have to scan the entire old space, including dead objects, looking for |
| 2687 | // pointers to new space. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2688 | void MarkCompactCollector::MigrateObject( |
| 2689 | HeapObject* dst, HeapObject* src, int size, AllocationSpace dest, |
| 2690 | SlotsBuffer** evacuation_slots_buffer) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2691 | Address dst_addr = dst->address(); |
| 2692 | Address src_addr = src->address(); |
| 2693 | DCHECK(heap()->AllowedToBeMigrated(src, dest)); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2694 | DCHECK(dest != LO_SPACE); |
| 2695 | if (dest == OLD_SPACE) { |
| 2696 | DCHECK_OBJECT_SIZE(size); |
| 2697 | DCHECK(evacuation_slots_buffer != nullptr); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2698 | DCHECK(IsAligned(size, kPointerSize)); |
| 2699 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2700 | heap()->MoveBlock(dst->address(), src->address(), size); |
| 2701 | RecordMigratedSlotVisitor visitor(this, evacuation_slots_buffer); |
| 2702 | dst->IterateBody(&visitor); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2703 | } else if (dest == CODE_SPACE) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2704 | DCHECK_CODEOBJECT_SIZE(size, heap()->code_space()); |
| 2705 | DCHECK(evacuation_slots_buffer != nullptr); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2706 | PROFILE(isolate(), CodeMoveEvent(src_addr, dst_addr)); |
| 2707 | heap()->MoveBlock(dst_addr, src_addr, size); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2708 | RecordMigratedCodeObjectSlot(dst_addr, evacuation_slots_buffer); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2709 | Code::cast(dst)->Relocate(dst_addr - src_addr); |
| 2710 | } else { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2711 | DCHECK_OBJECT_SIZE(size); |
| 2712 | DCHECK(evacuation_slots_buffer == nullptr); |
| 2713 | DCHECK(dest == NEW_SPACE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2714 | heap()->MoveBlock(dst_addr, src_addr, size); |
| 2715 | } |
| 2716 | heap()->OnMoveEvent(dst, src, size); |
| 2717 | Memory::Address_at(src_addr) = dst_addr; |
| 2718 | } |
| 2719 | |
| 2720 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2721 | static inline void UpdateSlot(Isolate* isolate, ObjectVisitor* v, |
| 2722 | SlotsBuffer::SlotType slot_type, Address addr) { |
| 2723 | switch (slot_type) { |
| 2724 | case SlotsBuffer::CODE_TARGET_SLOT: { |
| 2725 | RelocInfo rinfo(isolate, addr, RelocInfo::CODE_TARGET, 0, NULL); |
| 2726 | rinfo.Visit(isolate, v); |
| 2727 | break; |
| 2728 | } |
| 2729 | case SlotsBuffer::CELL_TARGET_SLOT: { |
| 2730 | RelocInfo rinfo(isolate, addr, RelocInfo::CELL, 0, NULL); |
| 2731 | rinfo.Visit(isolate, v); |
| 2732 | break; |
| 2733 | } |
| 2734 | case SlotsBuffer::CODE_ENTRY_SLOT: { |
| 2735 | v->VisitCodeEntry(addr); |
| 2736 | break; |
| 2737 | } |
| 2738 | case SlotsBuffer::RELOCATED_CODE_OBJECT: { |
| 2739 | HeapObject* obj = HeapObject::FromAddress(addr); |
| 2740 | Code::BodyDescriptor::IterateBody(obj, v); |
| 2741 | break; |
| 2742 | } |
| 2743 | case SlotsBuffer::DEBUG_TARGET_SLOT: { |
| 2744 | RelocInfo rinfo(isolate, addr, RelocInfo::DEBUG_BREAK_SLOT_AT_POSITION, 0, |
| 2745 | NULL); |
| 2746 | if (rinfo.IsPatchedDebugBreakSlotSequence()) rinfo.Visit(isolate, v); |
| 2747 | break; |
| 2748 | } |
| 2749 | case SlotsBuffer::EMBEDDED_OBJECT_SLOT: { |
| 2750 | RelocInfo rinfo(isolate, addr, RelocInfo::EMBEDDED_OBJECT, 0, NULL); |
| 2751 | rinfo.Visit(isolate, v); |
| 2752 | break; |
| 2753 | } |
| 2754 | case SlotsBuffer::OBJECT_SLOT: { |
| 2755 | v->VisitPointer(reinterpret_cast<Object**>(addr)); |
| 2756 | break; |
| 2757 | } |
| 2758 | default: |
| 2759 | UNREACHABLE(); |
| 2760 | break; |
| 2761 | } |
| 2762 | } |
| 2763 | |
| 2764 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2765 | // Visitor for updating pointers from live objects in old spaces to new space. |
| 2766 | // It does not expect to encounter pointers to dead objects. |
| 2767 | class PointersUpdatingVisitor : public ObjectVisitor { |
| 2768 | public: |
| 2769 | explicit PointersUpdatingVisitor(Heap* heap) : heap_(heap) {} |
| 2770 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2771 | void VisitPointer(Object** p) override { UpdatePointer(p); } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2772 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2773 | void VisitPointers(Object** start, Object** end) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2774 | for (Object** p = start; p < end; p++) UpdatePointer(p); |
| 2775 | } |
| 2776 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2777 | void VisitCell(RelocInfo* rinfo) override { |
| 2778 | DCHECK(rinfo->rmode() == RelocInfo::CELL); |
| 2779 | Object* cell = rinfo->target_cell(); |
| 2780 | Object* old_cell = cell; |
| 2781 | VisitPointer(&cell); |
| 2782 | if (cell != old_cell) { |
| 2783 | rinfo->set_target_cell(reinterpret_cast<Cell*>(cell)); |
| 2784 | } |
| 2785 | } |
| 2786 | |
| 2787 | void VisitEmbeddedPointer(RelocInfo* rinfo) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2788 | DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT); |
| 2789 | Object* target = rinfo->target_object(); |
| 2790 | Object* old_target = target; |
| 2791 | VisitPointer(&target); |
| 2792 | // Avoid unnecessary changes that might unnecessary flush the instruction |
| 2793 | // cache. |
| 2794 | if (target != old_target) { |
| 2795 | rinfo->set_target_object(target); |
| 2796 | } |
| 2797 | } |
| 2798 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2799 | void VisitCodeTarget(RelocInfo* rinfo) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2800 | DCHECK(RelocInfo::IsCodeTarget(rinfo->rmode())); |
| 2801 | Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address()); |
| 2802 | Object* old_target = target; |
| 2803 | VisitPointer(&target); |
| 2804 | if (target != old_target) { |
| 2805 | rinfo->set_target_address(Code::cast(target)->instruction_start()); |
| 2806 | } |
| 2807 | } |
| 2808 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2809 | void VisitCodeAgeSequence(RelocInfo* rinfo) override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2810 | DCHECK(RelocInfo::IsCodeAgeSequence(rinfo->rmode())); |
| 2811 | Object* stub = rinfo->code_age_stub(); |
| 2812 | DCHECK(stub != NULL); |
| 2813 | VisitPointer(&stub); |
| 2814 | if (stub != rinfo->code_age_stub()) { |
| 2815 | rinfo->set_code_age_stub(Code::cast(stub)); |
| 2816 | } |
| 2817 | } |
| 2818 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2819 | void VisitDebugTarget(RelocInfo* rinfo) override { |
| 2820 | DCHECK(RelocInfo::IsDebugBreakSlot(rinfo->rmode()) && |
| 2821 | rinfo->IsPatchedDebugBreakSlotSequence()); |
| 2822 | Object* target = |
| 2823 | Code::GetCodeFromTargetAddress(rinfo->debug_call_address()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2824 | VisitPointer(&target); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2825 | rinfo->set_debug_call_address(Code::cast(target)->instruction_start()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2826 | } |
| 2827 | |
| 2828 | static inline void UpdateSlot(Heap* heap, Object** slot) { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2829 | Object* obj = reinterpret_cast<Object*>( |
| 2830 | base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot))); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2831 | |
| 2832 | if (!obj->IsHeapObject()) return; |
| 2833 | |
| 2834 | HeapObject* heap_obj = HeapObject::cast(obj); |
| 2835 | |
| 2836 | MapWord map_word = heap_obj->map_word(); |
| 2837 | if (map_word.IsForwardingAddress()) { |
| 2838 | DCHECK(heap->InFromSpace(heap_obj) || |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2839 | MarkCompactCollector::IsOnEvacuationCandidate(heap_obj) || |
| 2840 | Page::FromAddress(heap_obj->address()) |
| 2841 | ->IsFlagSet(Page::COMPACTION_WAS_ABORTED)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2842 | HeapObject* target = map_word.ToForwardingAddress(); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 2843 | base::NoBarrier_CompareAndSwap( |
| 2844 | reinterpret_cast<base::AtomicWord*>(slot), |
| 2845 | reinterpret_cast<base::AtomicWord>(obj), |
| 2846 | reinterpret_cast<base::AtomicWord>(target)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2847 | DCHECK(!heap->InFromSpace(target) && |
| 2848 | !MarkCompactCollector::IsOnEvacuationCandidate(target)); |
| 2849 | } |
| 2850 | } |
| 2851 | |
| 2852 | private: |
| 2853 | inline void UpdatePointer(Object** p) { UpdateSlot(heap_, p); } |
| 2854 | |
| 2855 | Heap* heap_; |
| 2856 | }; |
| 2857 | |
| 2858 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2859 | void MarkCompactCollector::UpdateSlots(SlotsBuffer* buffer) { |
| 2860 | PointersUpdatingVisitor v(heap_); |
| 2861 | size_t buffer_size = buffer->Size(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2862 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2863 | for (size_t slot_idx = 0; slot_idx < buffer_size; ++slot_idx) { |
| 2864 | SlotsBuffer::ObjectSlot slot = buffer->Get(slot_idx); |
| 2865 | if (!SlotsBuffer::IsTypedSlot(slot)) { |
| 2866 | PointersUpdatingVisitor::UpdateSlot(heap_, slot); |
| 2867 | } else { |
| 2868 | ++slot_idx; |
| 2869 | DCHECK(slot_idx < buffer_size); |
| 2870 | UpdateSlot(heap_->isolate(), &v, DecodeSlotType(slot), |
| 2871 | reinterpret_cast<Address>(buffer->Get(slot_idx))); |
| 2872 | } |
| 2873 | } |
| 2874 | } |
| 2875 | |
| 2876 | |
| 2877 | void MarkCompactCollector::UpdateSlotsRecordedIn(SlotsBuffer* buffer) { |
| 2878 | while (buffer != NULL) { |
| 2879 | UpdateSlots(buffer); |
| 2880 | buffer = buffer->next(); |
| 2881 | } |
| 2882 | } |
| 2883 | |
| 2884 | |
| 2885 | static void UpdatePointer(HeapObject** address, HeapObject* object) { |
| 2886 | MapWord map_word = object->map_word(); |
| 2887 | // The store buffer can still contain stale pointers in dead large objects. |
| 2888 | // Ignore these pointers here. |
| 2889 | DCHECK(map_word.IsForwardingAddress() || |
| 2890 | object->GetHeap()->lo_space()->FindPage( |
| 2891 | reinterpret_cast<Address>(address)) != NULL); |
| 2892 | if (map_word.IsForwardingAddress()) { |
| 2893 | // Update the corresponding slot. |
| 2894 | *address = map_word.ToForwardingAddress(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2895 | } |
| 2896 | } |
| 2897 | |
| 2898 | |
| 2899 | static String* UpdateReferenceInExternalStringTableEntry(Heap* heap, |
| 2900 | Object** p) { |
| 2901 | MapWord map_word = HeapObject::cast(*p)->map_word(); |
| 2902 | |
| 2903 | if (map_word.IsForwardingAddress()) { |
| 2904 | return String::cast(map_word.ToForwardingAddress()); |
| 2905 | } |
| 2906 | |
| 2907 | return String::cast(*p); |
| 2908 | } |
| 2909 | |
| 2910 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2911 | bool MarkCompactCollector::IsSlotInBlackObject(Page* p, Address slot, |
| 2912 | HeapObject** out_object) { |
| 2913 | Space* owner = p->owner(); |
| 2914 | if (owner == heap_->lo_space() || owner == NULL) { |
| 2915 | Object* large_object = heap_->lo_space()->FindObject(slot); |
| 2916 | // This object has to exist, otherwise we would not have recorded a slot |
| 2917 | // for it. |
| 2918 | CHECK(large_object->IsHeapObject()); |
| 2919 | HeapObject* large_heap_object = HeapObject::cast(large_object); |
| 2920 | if (IsMarked(large_heap_object)) { |
| 2921 | *out_object = large_heap_object; |
| 2922 | return true; |
| 2923 | } |
| 2924 | return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2925 | } |
| 2926 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 2927 | uint32_t mark_bit_index = p->AddressToMarkbitIndex(slot); |
| 2928 | unsigned int cell_index = mark_bit_index >> Bitmap::kBitsPerCellLog2; |
| 2929 | MarkBit::CellType index_mask = 1u << Bitmap::IndexInCell(mark_bit_index); |
| 2930 | MarkBit::CellType* cells = p->markbits()->cells(); |
| 2931 | Address base_address = p->area_start(); |
| 2932 | unsigned int base_address_cell_index = Bitmap::IndexToCell( |
| 2933 | Bitmap::CellAlignIndex(p->AddressToMarkbitIndex(base_address))); |
| 2934 | |
| 2935 | // Check if the slot points to the start of an object. This can happen e.g. |
| 2936 | // when we left trim a fixed array. Such slots are invalid and we can remove |
| 2937 | // them. |
| 2938 | if (index_mask > 1) { |
| 2939 | if ((cells[cell_index] & index_mask) != 0 && |
| 2940 | (cells[cell_index] & (index_mask >> 1)) == 0) { |
| 2941 | return false; |
| 2942 | } |
| 2943 | } else { |
| 2944 | // Left trimming moves the mark bits so we cannot be in the very first cell. |
| 2945 | DCHECK(cell_index != base_address_cell_index); |
| 2946 | if ((cells[cell_index] & index_mask) != 0 && |
| 2947 | (cells[cell_index - 1] & (1u << Bitmap::kBitIndexMask)) == 0) { |
| 2948 | return false; |
| 2949 | } |
| 2950 | } |
| 2951 | |
| 2952 | // Check if the object is in the current cell. |
| 2953 | MarkBit::CellType slot_mask; |
| 2954 | if ((cells[cell_index] == 0) || |
| 2955 | (base::bits::CountTrailingZeros32(cells[cell_index]) > |
| 2956 | base::bits::CountTrailingZeros32(cells[cell_index] | index_mask))) { |
| 2957 | // If we are already in the first cell, there is no live object. |
| 2958 | if (cell_index == base_address_cell_index) return false; |
| 2959 | |
| 2960 | // If not, find a cell in a preceding cell slot that has a mark bit set. |
| 2961 | do { |
| 2962 | cell_index--; |
| 2963 | } while (cell_index > base_address_cell_index && cells[cell_index] == 0); |
| 2964 | |
| 2965 | // The slot must be in a dead object if there are no preceding cells that |
| 2966 | // have mark bits set. |
| 2967 | if (cells[cell_index] == 0) { |
| 2968 | return false; |
| 2969 | } |
| 2970 | |
| 2971 | // The object is in a preceding cell. Set the mask to find any object. |
| 2972 | slot_mask = ~0u; |
| 2973 | } else { |
| 2974 | // We are interested in object mark bits right before the slot. |
| 2975 | slot_mask = index_mask + (index_mask - 1); |
| 2976 | } |
| 2977 | |
| 2978 | MarkBit::CellType current_cell = cells[cell_index]; |
| 2979 | CHECK(current_cell != 0); |
| 2980 | |
| 2981 | // Find the last live object in the cell. |
| 2982 | unsigned int leading_zeros = |
| 2983 | base::bits::CountLeadingZeros32(current_cell & slot_mask); |
| 2984 | CHECK(leading_zeros != Bitmap::kBitsPerCell); |
| 2985 | int offset = static_cast<int>(Bitmap::kBitIndexMask - leading_zeros) - 1; |
| 2986 | |
| 2987 | base_address += (cell_index - base_address_cell_index) * |
| 2988 | Bitmap::kBitsPerCell * kPointerSize; |
| 2989 | Address address = base_address + offset * kPointerSize; |
| 2990 | HeapObject* object = HeapObject::FromAddress(address); |
| 2991 | CHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 2992 | CHECK(object->address() < reinterpret_cast<Address>(slot)); |
| 2993 | if ((object->address() + kPointerSize) <= slot && |
| 2994 | (object->address() + object->Size()) > slot) { |
| 2995 | // If the slot is within the last found object in the cell, the slot is |
| 2996 | // in a live object. |
| 2997 | // Slots pointing to the first word of an object are invalid and removed. |
| 2998 | // This can happen when we move the object header while left trimming. |
| 2999 | *out_object = object; |
| 3000 | return true; |
| 3001 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3002 | return false; |
| 3003 | } |
| 3004 | |
| 3005 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3006 | bool MarkCompactCollector::IsSlotInBlackObjectSlow(Page* p, Address slot) { |
| 3007 | // This function does not support large objects right now. |
| 3008 | Space* owner = p->owner(); |
| 3009 | if (owner == heap_->lo_space() || owner == NULL) { |
| 3010 | Object* large_object = heap_->lo_space()->FindObject(slot); |
| 3011 | // This object has to exist, otherwise we would not have recorded a slot |
| 3012 | // for it. |
| 3013 | CHECK(large_object->IsHeapObject()); |
| 3014 | HeapObject* large_heap_object = HeapObject::cast(large_object); |
| 3015 | if (IsMarked(large_heap_object)) { |
| 3016 | return true; |
| 3017 | } |
| 3018 | return false; |
| 3019 | } |
| 3020 | |
| 3021 | LiveObjectIterator<kBlackObjects> it(p); |
| 3022 | HeapObject* object = NULL; |
| 3023 | while ((object = it.Next()) != NULL) { |
| 3024 | int size = object->Size(); |
| 3025 | |
| 3026 | if (object->address() > slot) return false; |
| 3027 | if (object->address() <= slot && slot < (object->address() + size)) { |
| 3028 | return true; |
| 3029 | } |
| 3030 | } |
| 3031 | return false; |
| 3032 | } |
| 3033 | |
| 3034 | |
| 3035 | bool MarkCompactCollector::IsSlotInLiveObject(Address slot) { |
| 3036 | HeapObject* object = NULL; |
| 3037 | // The target object is black but we don't know if the source slot is black. |
| 3038 | // The source object could have died and the slot could be part of a free |
| 3039 | // space. Find out based on mark bits if the slot is part of a live object. |
| 3040 | if (!IsSlotInBlackObject(Page::FromAddress(slot), slot, &object)) { |
| 3041 | return false; |
| 3042 | } |
| 3043 | |
| 3044 | DCHECK(object != NULL); |
| 3045 | int offset = static_cast<int>(slot - object->address()); |
| 3046 | return object->IsValidSlot(offset); |
| 3047 | } |
| 3048 | |
| 3049 | |
| 3050 | void MarkCompactCollector::VerifyIsSlotInLiveObject(Address slot, |
| 3051 | HeapObject* object) { |
| 3052 | // The target object has to be black. |
| 3053 | CHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 3054 | |
| 3055 | // The target object is black but we don't know if the source slot is black. |
| 3056 | // The source object could have died and the slot could be part of a free |
| 3057 | // space. Use the mark bit iterator to find out about liveness of the slot. |
| 3058 | CHECK(IsSlotInBlackObjectSlow(Page::FromAddress(slot), slot)); |
| 3059 | } |
| 3060 | |
| 3061 | |
| 3062 | void MarkCompactCollector::EvacuateNewSpacePrologue() { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3063 | // There are soft limits in the allocation code, designed trigger a mark |
| 3064 | // sweep collection by failing allocations. But since we are already in |
| 3065 | // a mark-sweep allocation, there is no sense in trying to trigger one. |
| 3066 | AlwaysAllocateScope scope(isolate()); |
| 3067 | |
| 3068 | NewSpace* new_space = heap()->new_space(); |
| 3069 | |
| 3070 | // Store allocation range before flipping semispaces. |
| 3071 | Address from_bottom = new_space->bottom(); |
| 3072 | Address from_top = new_space->top(); |
| 3073 | |
| 3074 | // Flip the semispaces. After flipping, to space is empty, from space has |
| 3075 | // live objects. |
| 3076 | new_space->Flip(); |
| 3077 | new_space->ResetAllocationInfo(); |
| 3078 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3079 | newspace_evacuation_candidates_.Clear(); |
| 3080 | NewSpacePageIterator it(from_bottom, from_top); |
| 3081 | while (it.has_next()) { |
| 3082 | newspace_evacuation_candidates_.Add(it.next()); |
| 3083 | } |
| 3084 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3085 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3086 | |
| 3087 | HashMap* MarkCompactCollector::EvacuateNewSpaceInParallel() { |
| 3088 | HashMap* local_pretenuring_feedback = new HashMap( |
| 3089 | HashMap::PointersMatch, kInitialLocalPretenuringFeedbackCapacity); |
| 3090 | EvacuateNewSpaceVisitor new_space_visitor(heap(), &migration_slots_buffer_, |
| 3091 | local_pretenuring_feedback); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3092 | // First pass: traverse all objects in inactive semispace, remove marks, |
| 3093 | // migrate live objects and write forwarding addresses. This stage puts |
| 3094 | // new entries in the store buffer and may cause some pages to be marked |
| 3095 | // scan-on-scavenge. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3096 | for (int i = 0; i < newspace_evacuation_candidates_.length(); i++) { |
| 3097 | NewSpacePage* p = |
| 3098 | reinterpret_cast<NewSpacePage*>(newspace_evacuation_candidates_[i]); |
| 3099 | bool ok = VisitLiveObjects(p, &new_space_visitor, kClearMarkbits); |
| 3100 | USE(ok); |
| 3101 | DCHECK(ok); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3102 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3103 | heap_->IncrementPromotedObjectsSize( |
| 3104 | static_cast<int>(new_space_visitor.promoted_size())); |
| 3105 | heap_->IncrementSemiSpaceCopiedObjectSize( |
| 3106 | static_cast<int>(new_space_visitor.semispace_copied_size())); |
| 3107 | heap_->IncrementYoungSurvivorsCounter( |
| 3108 | static_cast<int>(new_space_visitor.promoted_size()) + |
| 3109 | static_cast<int>(new_space_visitor.semispace_copied_size())); |
| 3110 | return local_pretenuring_feedback; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3111 | } |
| 3112 | |
| 3113 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3114 | void MarkCompactCollector::AddEvacuationSlotsBufferSynchronized( |
| 3115 | SlotsBuffer* evacuation_slots_buffer) { |
| 3116 | base::LockGuard<base::Mutex> lock_guard(&evacuation_slots_buffers_mutex_); |
| 3117 | evacuation_slots_buffers_.Add(evacuation_slots_buffer); |
| 3118 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3119 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3120 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3121 | int MarkCompactCollector::NumberOfParallelCompactionTasks() { |
| 3122 | if (!FLAG_parallel_compaction) return 1; |
| 3123 | // Compute the number of needed tasks based on a target compaction time, the |
| 3124 | // profiled compaction speed and marked live memory. |
| 3125 | // |
| 3126 | // The number of parallel compaction tasks is limited by: |
| 3127 | // - #evacuation pages |
| 3128 | // - (#cores - 1) |
| 3129 | // - a hard limit |
| 3130 | const double kTargetCompactionTimeInMs = 1; |
| 3131 | const int kMaxCompactionTasks = 8; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3132 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3133 | intptr_t compaction_speed = |
| 3134 | heap()->tracer()->CompactionSpeedInBytesPerMillisecond(); |
| 3135 | if (compaction_speed == 0) return 1; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3136 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3137 | intptr_t live_bytes = 0; |
| 3138 | for (Page* page : evacuation_candidates_) { |
| 3139 | live_bytes += page->LiveBytes(); |
| 3140 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3141 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3142 | const int cores = Max(1, base::SysInfo::NumberOfProcessors() - 1); |
| 3143 | const int tasks = |
| 3144 | 1 + static_cast<int>(static_cast<double>(live_bytes) / compaction_speed / |
| 3145 | kTargetCompactionTimeInMs); |
| 3146 | const int tasks_capped_pages = Min(evacuation_candidates_.length(), tasks); |
| 3147 | const int tasks_capped_cores = Min(cores, tasks_capped_pages); |
| 3148 | const int tasks_capped_hard = Min(kMaxCompactionTasks, tasks_capped_cores); |
| 3149 | return tasks_capped_hard; |
| 3150 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3151 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3152 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3153 | void MarkCompactCollector::EvacuatePagesInParallel() { |
| 3154 | const int num_pages = evacuation_candidates_.length(); |
| 3155 | if (num_pages == 0) return; |
| 3156 | |
| 3157 | // Used for trace summary. |
| 3158 | intptr_t live_bytes = 0; |
| 3159 | intptr_t compaction_speed = 0; |
| 3160 | if (FLAG_trace_fragmentation) { |
| 3161 | for (Page* page : evacuation_candidates_) { |
| 3162 | live_bytes += page->LiveBytes(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3163 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3164 | compaction_speed = heap()->tracer()->CompactionSpeedInBytesPerMillisecond(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3165 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3166 | const int num_tasks = NumberOfParallelCompactionTasks(); |
| 3167 | |
| 3168 | // Set up compaction spaces. |
| 3169 | CompactionSpaceCollection** compaction_spaces_for_tasks = |
| 3170 | new CompactionSpaceCollection*[num_tasks]; |
| 3171 | for (int i = 0; i < num_tasks; i++) { |
| 3172 | compaction_spaces_for_tasks[i] = new CompactionSpaceCollection(heap()); |
| 3173 | } |
| 3174 | |
| 3175 | heap()->old_space()->DivideUponCompactionSpaces(compaction_spaces_for_tasks, |
| 3176 | num_tasks); |
| 3177 | heap()->code_space()->DivideUponCompactionSpaces(compaction_spaces_for_tasks, |
| 3178 | num_tasks); |
| 3179 | |
| 3180 | uint32_t* task_ids = new uint32_t[num_tasks - 1]; |
| 3181 | // Kick off parallel tasks. |
| 3182 | StartParallelCompaction(compaction_spaces_for_tasks, task_ids, num_tasks); |
| 3183 | // Wait for unfinished and not-yet-started tasks. |
| 3184 | WaitUntilCompactionCompleted(task_ids, num_tasks - 1); |
| 3185 | delete[] task_ids; |
| 3186 | |
| 3187 | double compaction_duration = 0.0; |
| 3188 | intptr_t compacted_memory = 0; |
| 3189 | // Merge back memory (compacted and unused) from compaction spaces. |
| 3190 | for (int i = 0; i < num_tasks; i++) { |
| 3191 | heap()->old_space()->MergeCompactionSpace( |
| 3192 | compaction_spaces_for_tasks[i]->Get(OLD_SPACE)); |
| 3193 | heap()->code_space()->MergeCompactionSpace( |
| 3194 | compaction_spaces_for_tasks[i]->Get(CODE_SPACE)); |
| 3195 | compacted_memory += compaction_spaces_for_tasks[i]->bytes_compacted(); |
| 3196 | compaction_duration += compaction_spaces_for_tasks[i]->duration(); |
| 3197 | delete compaction_spaces_for_tasks[i]; |
| 3198 | } |
| 3199 | delete[] compaction_spaces_for_tasks; |
| 3200 | heap()->tracer()->AddCompactionEvent(compaction_duration, compacted_memory); |
| 3201 | |
| 3202 | // Finalize sequentially. |
| 3203 | int abandoned_pages = 0; |
| 3204 | for (int i = 0; i < num_pages; i++) { |
| 3205 | Page* p = evacuation_candidates_[i]; |
| 3206 | switch (p->parallel_compaction_state().Value()) { |
| 3207 | case MemoryChunk::ParallelCompactingState::kCompactingAborted: |
| 3208 | // We have partially compacted the page, i.e., some objects may have |
| 3209 | // moved, others are still in place. |
| 3210 | // We need to: |
| 3211 | // - Leave the evacuation candidate flag for later processing of |
| 3212 | // slots buffer entries. |
| 3213 | // - Leave the slots buffer there for processing of entries added by |
| 3214 | // the write barrier. |
| 3215 | // - Rescan the page as slot recording in the migration buffer only |
| 3216 | // happens upon moving (which we potentially didn't do). |
| 3217 | // - Leave the page in the list of pages of a space since we could not |
| 3218 | // fully evacuate it. |
| 3219 | // - Mark them for rescanning for store buffer entries as we otherwise |
| 3220 | // might have stale store buffer entries that become "valid" again |
| 3221 | // after reusing the memory. Note that all existing store buffer |
| 3222 | // entries of such pages are filtered before rescanning. |
| 3223 | DCHECK(p->IsEvacuationCandidate()); |
| 3224 | p->SetFlag(Page::COMPACTION_WAS_ABORTED); |
| 3225 | p->set_scan_on_scavenge(true); |
| 3226 | abandoned_pages++; |
| 3227 | break; |
| 3228 | case MemoryChunk::kCompactingFinalize: |
| 3229 | DCHECK(p->IsEvacuationCandidate()); |
| 3230 | p->SetWasSwept(); |
| 3231 | p->Unlink(); |
| 3232 | break; |
| 3233 | case MemoryChunk::kCompactingDone: |
| 3234 | DCHECK(p->IsFlagSet(Page::POPULAR_PAGE)); |
| 3235 | DCHECK(p->IsFlagSet(Page::RESCAN_ON_EVACUATION)); |
| 3236 | break; |
| 3237 | default: |
| 3238 | // We should not observe kCompactingInProgress, or kCompactingDone. |
| 3239 | UNREACHABLE(); |
| 3240 | } |
| 3241 | p->parallel_compaction_state().SetValue(MemoryChunk::kCompactingDone); |
| 3242 | } |
| 3243 | if (FLAG_trace_fragmentation) { |
| 3244 | PrintIsolate(isolate(), |
| 3245 | "%8.0f ms: compaction: parallel=%d pages=%d aborted=%d " |
| 3246 | "tasks=%d cores=%d live_bytes=%" V8_PTR_PREFIX |
| 3247 | "d compaction_speed=%" V8_PTR_PREFIX "d\n", |
| 3248 | isolate()->time_millis_since_init(), FLAG_parallel_compaction, |
| 3249 | num_pages, abandoned_pages, num_tasks, |
| 3250 | base::SysInfo::NumberOfProcessors(), live_bytes, |
| 3251 | compaction_speed); |
| 3252 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3253 | } |
| 3254 | |
| 3255 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3256 | void MarkCompactCollector::StartParallelCompaction( |
| 3257 | CompactionSpaceCollection** compaction_spaces, uint32_t* task_ids, |
| 3258 | int len) { |
| 3259 | compaction_in_progress_ = true; |
| 3260 | for (int i = 1; i < len; i++) { |
| 3261 | CompactionTask* task = new CompactionTask(heap(), compaction_spaces[i]); |
| 3262 | task_ids[i - 1] = task->id(); |
| 3263 | V8::GetCurrentPlatform()->CallOnBackgroundThread( |
| 3264 | task, v8::Platform::kShortRunningTask); |
| 3265 | } |
| 3266 | |
| 3267 | // Contribute in main thread. |
| 3268 | EvacuatePages(compaction_spaces[0], &migration_slots_buffer_); |
| 3269 | } |
| 3270 | |
| 3271 | |
| 3272 | void MarkCompactCollector::WaitUntilCompactionCompleted(uint32_t* task_ids, |
| 3273 | int len) { |
| 3274 | // Try to cancel compaction tasks that have not been run (as they might be |
| 3275 | // stuck in a worker queue). Tasks that cannot be canceled, have either |
| 3276 | // already completed or are still running, hence we need to wait for their |
| 3277 | // semaphore signal. |
| 3278 | for (int i = 0; i < len; i++) { |
| 3279 | if (!heap()->isolate()->cancelable_task_manager()->TryAbort(task_ids[i])) { |
| 3280 | pending_compaction_tasks_semaphore_.Wait(); |
| 3281 | } |
| 3282 | } |
| 3283 | compaction_in_progress_ = false; |
| 3284 | } |
| 3285 | |
| 3286 | |
| 3287 | void MarkCompactCollector::EvacuatePages( |
| 3288 | CompactionSpaceCollection* compaction_spaces, |
| 3289 | SlotsBuffer** evacuation_slots_buffer) { |
| 3290 | EvacuateOldSpaceVisitor visitor(heap(), compaction_spaces, |
| 3291 | evacuation_slots_buffer); |
| 3292 | for (int i = 0; i < evacuation_candidates_.length(); i++) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3293 | Page* p = evacuation_candidates_[i]; |
| 3294 | DCHECK(p->IsEvacuationCandidate() || |
| 3295 | p->IsFlagSet(Page::RESCAN_ON_EVACUATION)); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3296 | DCHECK(static_cast<int>(p->parallel_sweeping_state().Value()) == |
| 3297 | MemoryChunk::kSweepingDone); |
| 3298 | if (p->parallel_compaction_state().TrySetValue( |
| 3299 | MemoryChunk::kCompactingDone, MemoryChunk::kCompactingInProgress)) { |
| 3300 | if (p->IsEvacuationCandidate()) { |
| 3301 | DCHECK_EQ(p->parallel_compaction_state().Value(), |
| 3302 | MemoryChunk::kCompactingInProgress); |
| 3303 | double start = heap()->MonotonicallyIncreasingTimeInMs(); |
| 3304 | intptr_t live_bytes = p->LiveBytes(); |
| 3305 | AlwaysAllocateScope always_allocate(isolate()); |
| 3306 | if (VisitLiveObjects(p, &visitor, kClearMarkbits)) { |
| 3307 | p->ResetLiveBytes(); |
| 3308 | p->parallel_compaction_state().SetValue( |
| 3309 | MemoryChunk::kCompactingFinalize); |
| 3310 | compaction_spaces->ReportCompactionProgress( |
| 3311 | heap()->MonotonicallyIncreasingTimeInMs() - start, live_bytes); |
| 3312 | } else { |
| 3313 | p->parallel_compaction_state().SetValue( |
| 3314 | MemoryChunk::kCompactingAborted); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3315 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3316 | } else { |
| 3317 | // There could be popular pages in the list of evacuation candidates |
| 3318 | // which we do compact. |
| 3319 | p->parallel_compaction_state().SetValue(MemoryChunk::kCompactingDone); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3320 | } |
| 3321 | } |
| 3322 | } |
| 3323 | } |
| 3324 | |
| 3325 | |
| 3326 | class EvacuationWeakObjectRetainer : public WeakObjectRetainer { |
| 3327 | public: |
| 3328 | virtual Object* RetainAs(Object* object) { |
| 3329 | if (object->IsHeapObject()) { |
| 3330 | HeapObject* heap_object = HeapObject::cast(object); |
| 3331 | MapWord map_word = heap_object->map_word(); |
| 3332 | if (map_word.IsForwardingAddress()) { |
| 3333 | return map_word.ToForwardingAddress(); |
| 3334 | } |
| 3335 | } |
| 3336 | return object; |
| 3337 | } |
| 3338 | }; |
| 3339 | |
| 3340 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3341 | enum SweepingMode { SWEEP_ONLY, SWEEP_AND_VISIT_LIVE_OBJECTS }; |
| 3342 | |
| 3343 | |
| 3344 | enum SkipListRebuildingMode { REBUILD_SKIP_LIST, IGNORE_SKIP_LIST }; |
| 3345 | |
| 3346 | |
| 3347 | enum FreeSpaceTreatmentMode { IGNORE_FREE_SPACE, ZAP_FREE_SPACE }; |
| 3348 | |
| 3349 | |
| 3350 | template <MarkCompactCollector::SweepingParallelism mode> |
| 3351 | static intptr_t Free(PagedSpace* space, FreeList* free_list, Address start, |
| 3352 | int size) { |
| 3353 | if (mode == MarkCompactCollector::SWEEP_ON_MAIN_THREAD) { |
| 3354 | DCHECK(free_list == NULL); |
| 3355 | return space->Free(start, size); |
| 3356 | } else { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3357 | return size - free_list->Free(start, size); |
| 3358 | } |
| 3359 | } |
| 3360 | |
| 3361 | |
| 3362 | // Sweeps a page. After sweeping the page can be iterated. |
| 3363 | // Slots in live objects pointing into evacuation candidates are updated |
| 3364 | // if requested. |
| 3365 | // Returns the size of the biggest continuous freed memory chunk in bytes. |
| 3366 | template <SweepingMode sweeping_mode, |
| 3367 | MarkCompactCollector::SweepingParallelism parallelism, |
| 3368 | SkipListRebuildingMode skip_list_mode, |
| 3369 | FreeSpaceTreatmentMode free_space_mode> |
| 3370 | static int Sweep(PagedSpace* space, FreeList* free_list, Page* p, |
| 3371 | ObjectVisitor* v) { |
| 3372 | DCHECK(!p->IsEvacuationCandidate() && !p->WasSwept()); |
| 3373 | DCHECK_EQ(skip_list_mode == REBUILD_SKIP_LIST, |
| 3374 | space->identity() == CODE_SPACE); |
| 3375 | DCHECK((p->skip_list() == NULL) || (skip_list_mode == REBUILD_SKIP_LIST)); |
| 3376 | DCHECK(parallelism == MarkCompactCollector::SWEEP_ON_MAIN_THREAD || |
| 3377 | sweeping_mode == SWEEP_ONLY); |
| 3378 | |
| 3379 | Address free_start = p->area_start(); |
| 3380 | DCHECK(reinterpret_cast<intptr_t>(free_start) % (32 * kPointerSize) == 0); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3381 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3382 | // If we use the skip list for code space pages, we have to lock the skip |
| 3383 | // list because it could be accessed concurrently by the runtime or the |
| 3384 | // deoptimizer. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3385 | SkipList* skip_list = p->skip_list(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3386 | if ((skip_list_mode == REBUILD_SKIP_LIST) && skip_list) { |
| 3387 | skip_list->Clear(); |
| 3388 | } |
| 3389 | |
| 3390 | intptr_t freed_bytes = 0; |
| 3391 | intptr_t max_freed_bytes = 0; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3392 | int curr_region = -1; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3393 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3394 | LiveObjectIterator<kBlackObjects> it(p); |
| 3395 | HeapObject* object = NULL; |
| 3396 | while ((object = it.Next()) != NULL) { |
| 3397 | DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 3398 | Address free_end = object->address(); |
| 3399 | if (free_end != free_start) { |
| 3400 | int size = static_cast<int>(free_end - free_start); |
| 3401 | if (free_space_mode == ZAP_FREE_SPACE) { |
| 3402 | memset(free_start, 0xcc, size); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3403 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3404 | freed_bytes = Free<parallelism>(space, free_list, free_start, size); |
| 3405 | max_freed_bytes = Max(freed_bytes, max_freed_bytes); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3406 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3407 | Map* map = object->synchronized_map(); |
| 3408 | int size = object->SizeFromMap(map); |
| 3409 | if (sweeping_mode == SWEEP_AND_VISIT_LIVE_OBJECTS) { |
| 3410 | object->IterateBody(map->instance_type(), size, v); |
| 3411 | } |
| 3412 | if ((skip_list_mode == REBUILD_SKIP_LIST) && skip_list != NULL) { |
| 3413 | int new_region_start = SkipList::RegionNumber(free_end); |
| 3414 | int new_region_end = |
| 3415 | SkipList::RegionNumber(free_end + size - kPointerSize); |
| 3416 | if (new_region_start != curr_region || new_region_end != curr_region) { |
| 3417 | skip_list->AddObject(free_end, size); |
| 3418 | curr_region = new_region_end; |
| 3419 | } |
| 3420 | } |
| 3421 | free_start = free_end + size; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3422 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3423 | |
| 3424 | // Clear the mark bits of that page and reset live bytes count. |
| 3425 | Bitmap::Clear(p); |
| 3426 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3427 | if (free_start != p->area_end()) { |
| 3428 | int size = static_cast<int>(p->area_end() - free_start); |
| 3429 | if (free_space_mode == ZAP_FREE_SPACE) { |
| 3430 | memset(free_start, 0xcc, size); |
| 3431 | } |
| 3432 | freed_bytes = Free<parallelism>(space, free_list, free_start, size); |
| 3433 | max_freed_bytes = Max(freed_bytes, max_freed_bytes); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3434 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3435 | |
| 3436 | if (parallelism == MarkCompactCollector::SWEEP_IN_PARALLEL) { |
| 3437 | // When concurrent sweeping is active, the page will be marked after |
| 3438 | // sweeping by the main thread. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3439 | p->parallel_sweeping_state().SetValue(MemoryChunk::kSweepingFinalize); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3440 | } else { |
| 3441 | p->SetWasSwept(); |
| 3442 | } |
| 3443 | return FreeList::GuaranteedAllocatable(static_cast<int>(max_freed_bytes)); |
| 3444 | } |
| 3445 | |
| 3446 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3447 | void MarkCompactCollector::InvalidateCode(Code* code) { |
| 3448 | if (heap_->incremental_marking()->IsCompacting() && |
| 3449 | !ShouldSkipEvacuationSlotRecording(code)) { |
| 3450 | DCHECK(compacting_); |
| 3451 | |
| 3452 | // If the object is white than no slots were recorded on it yet. |
| 3453 | MarkBit mark_bit = Marking::MarkBitFrom(code); |
| 3454 | if (Marking::IsWhite(mark_bit)) return; |
| 3455 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3456 | // Ignore all slots that might have been recorded in the body of the |
| 3457 | // deoptimized code object. Assumption: no slots will be recorded for |
| 3458 | // this object after invalidating it. |
| 3459 | RemoveObjectSlots(code->instruction_start(), |
| 3460 | code->address() + code->Size()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3461 | } |
| 3462 | } |
| 3463 | |
| 3464 | |
| 3465 | // Return true if the given code is deoptimized or will be deoptimized. |
| 3466 | bool MarkCompactCollector::WillBeDeoptimized(Code* code) { |
| 3467 | return code->is_optimized_code() && code->marked_for_deoptimization(); |
| 3468 | } |
| 3469 | |
| 3470 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3471 | void MarkCompactCollector::RemoveObjectSlots(Address start_slot, |
| 3472 | Address end_slot) { |
| 3473 | // Remove entries by replacing them with an old-space slot containing a smi |
| 3474 | // that is located in an unmovable page. |
| 3475 | int npages = evacuation_candidates_.length(); |
| 3476 | for (int i = 0; i < npages; i++) { |
| 3477 | Page* p = evacuation_candidates_[i]; |
| 3478 | DCHECK(p->IsEvacuationCandidate() || |
| 3479 | p->IsFlagSet(Page::RESCAN_ON_EVACUATION)); |
| 3480 | if (p->IsEvacuationCandidate()) { |
| 3481 | SlotsBuffer::RemoveObjectSlots(heap_, p->slots_buffer(), start_slot, |
| 3482 | end_slot); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3483 | } |
| 3484 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3485 | } |
| 3486 | |
| 3487 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3488 | #ifdef VERIFY_HEAP |
| 3489 | static void VerifyAllBlackObjects(MemoryChunk* page) { |
| 3490 | LiveObjectIterator<kAllLiveObjects> it(page); |
| 3491 | HeapObject* object = NULL; |
| 3492 | while ((object = it.Next()) != NULL) { |
| 3493 | CHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 3494 | } |
| 3495 | } |
| 3496 | #endif // VERIFY_HEAP |
| 3497 | |
| 3498 | |
| 3499 | bool MarkCompactCollector::VisitLiveObjects(MemoryChunk* page, |
| 3500 | HeapObjectVisitor* visitor, |
| 3501 | IterationMode mode) { |
| 3502 | #ifdef VERIFY_HEAP |
| 3503 | VerifyAllBlackObjects(page); |
| 3504 | #endif // VERIFY_HEAP |
| 3505 | |
| 3506 | LiveObjectIterator<kBlackObjects> it(page); |
| 3507 | HeapObject* object = nullptr; |
| 3508 | while ((object = it.Next()) != nullptr) { |
| 3509 | DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 3510 | if (!visitor->Visit(object)) { |
| 3511 | if (mode == kClearMarkbits) { |
| 3512 | page->markbits()->ClearRange( |
| 3513 | page->AddressToMarkbitIndex(page->area_start()), |
| 3514 | page->AddressToMarkbitIndex(object->address())); |
| 3515 | RecomputeLiveBytes(page); |
| 3516 | } |
| 3517 | return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3518 | } |
| 3519 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3520 | if (mode == kClearMarkbits) { |
| 3521 | Bitmap::Clear(page); |
| 3522 | } |
| 3523 | return true; |
| 3524 | } |
| 3525 | |
| 3526 | |
| 3527 | void MarkCompactCollector::RecomputeLiveBytes(MemoryChunk* page) { |
| 3528 | LiveObjectIterator<kBlackObjects> it(page); |
| 3529 | int new_live_size = 0; |
| 3530 | HeapObject* object = nullptr; |
| 3531 | while ((object = it.Next()) != nullptr) { |
| 3532 | new_live_size += object->Size(); |
| 3533 | } |
| 3534 | page->SetLiveBytes(new_live_size); |
| 3535 | } |
| 3536 | |
| 3537 | |
| 3538 | void MarkCompactCollector::VisitLiveObjectsBody(Page* page, |
| 3539 | ObjectVisitor* visitor) { |
| 3540 | #ifdef VERIFY_HEAP |
| 3541 | VerifyAllBlackObjects(page); |
| 3542 | #endif // VERIFY_HEAP |
| 3543 | |
| 3544 | LiveObjectIterator<kBlackObjects> it(page); |
| 3545 | HeapObject* object = NULL; |
| 3546 | while ((object = it.Next()) != NULL) { |
| 3547 | DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object))); |
| 3548 | Map* map = object->synchronized_map(); |
| 3549 | int size = object->SizeFromMap(map); |
| 3550 | object->IterateBody(map->instance_type(), size, visitor); |
| 3551 | } |
| 3552 | } |
| 3553 | |
| 3554 | |
| 3555 | void MarkCompactCollector::SweepAbortedPages() { |
| 3556 | // Second pass on aborted pages. |
| 3557 | for (int i = 0; i < evacuation_candidates_.length(); i++) { |
| 3558 | Page* p = evacuation_candidates_[i]; |
| 3559 | if (p->IsFlagSet(Page::COMPACTION_WAS_ABORTED)) { |
| 3560 | p->ClearFlag(MemoryChunk::COMPACTION_WAS_ABORTED); |
| 3561 | PagedSpace* space = static_cast<PagedSpace*>(p->owner()); |
| 3562 | switch (space->identity()) { |
| 3563 | case OLD_SPACE: |
| 3564 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST, |
| 3565 | IGNORE_FREE_SPACE>(space, nullptr, p, nullptr); |
| 3566 | break; |
| 3567 | case CODE_SPACE: |
| 3568 | if (FLAG_zap_code_space) { |
| 3569 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST, |
| 3570 | ZAP_FREE_SPACE>(space, NULL, p, nullptr); |
| 3571 | } else { |
| 3572 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST, |
| 3573 | IGNORE_FREE_SPACE>(space, NULL, p, nullptr); |
| 3574 | } |
| 3575 | break; |
| 3576 | default: |
| 3577 | UNREACHABLE(); |
| 3578 | break; |
| 3579 | } |
| 3580 | } |
| 3581 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3582 | } |
| 3583 | |
| 3584 | |
| 3585 | void MarkCompactCollector::EvacuateNewSpaceAndCandidates() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3586 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_EVACUATE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3587 | Heap::RelocationLock relocation_lock(heap()); |
| 3588 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3589 | HashMap* local_pretenuring_feedback = nullptr; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3590 | { |
| 3591 | GCTracer::Scope gc_scope(heap()->tracer(), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3592 | GCTracer::Scope::MC_EVACUATE_NEW_SPACE); |
| 3593 | EvacuationScope evacuation_scope(this); |
| 3594 | EvacuateNewSpacePrologue(); |
| 3595 | local_pretenuring_feedback = EvacuateNewSpaceInParallel(); |
| 3596 | heap_->new_space()->set_age_mark(heap_->new_space()->top()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3597 | } |
| 3598 | |
| 3599 | { |
| 3600 | GCTracer::Scope gc_scope(heap()->tracer(), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3601 | GCTracer::Scope::MC_EVACUATE_CANDIDATES); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 3602 | EvacuationScope evacuation_scope(this); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3603 | EvacuatePagesInParallel(); |
| 3604 | } |
| 3605 | |
| 3606 | { |
| 3607 | heap_->MergeAllocationSitePretenuringFeedback(*local_pretenuring_feedback); |
| 3608 | delete local_pretenuring_feedback; |
| 3609 | } |
| 3610 | |
| 3611 | UpdatePointersAfterEvacuation(); |
| 3612 | |
| 3613 | { |
| 3614 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 3615 | GCTracer::Scope::MC_EVACUATE_CLEAN_UP); |
| 3616 | // After updating all pointers, we can finally sweep the aborted pages, |
| 3617 | // effectively overriding any forward pointers. |
| 3618 | SweepAbortedPages(); |
| 3619 | |
| 3620 | // EvacuateNewSpaceAndCandidates iterates over new space objects and for |
| 3621 | // ArrayBuffers either re-registers them as live or promotes them. This is |
| 3622 | // needed to properly free them. |
| 3623 | heap()->array_buffer_tracker()->FreeDead(false); |
| 3624 | |
| 3625 | // Deallocate evacuated candidate pages. |
| 3626 | ReleaseEvacuationCandidates(); |
| 3627 | } |
| 3628 | |
| 3629 | #ifdef VERIFY_HEAP |
| 3630 | if (FLAG_verify_heap && !sweeping_in_progress_) { |
| 3631 | VerifyEvacuation(heap()); |
| 3632 | } |
| 3633 | #endif |
| 3634 | } |
| 3635 | |
| 3636 | |
| 3637 | void MarkCompactCollector::UpdatePointersAfterEvacuation() { |
| 3638 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 3639 | GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS); |
| 3640 | { |
| 3641 | GCTracer::Scope gc_scope( |
| 3642 | heap()->tracer(), |
| 3643 | GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_TO_EVACUATED); |
| 3644 | UpdateSlotsRecordedIn(migration_slots_buffer_); |
| 3645 | if (FLAG_trace_fragmentation_verbose) { |
| 3646 | PrintF(" migration slots buffer: %d\n", |
| 3647 | SlotsBuffer::SizeOfChain(migration_slots_buffer_)); |
| 3648 | } |
| 3649 | slots_buffer_allocator_->DeallocateChain(&migration_slots_buffer_); |
| 3650 | DCHECK(migration_slots_buffer_ == NULL); |
| 3651 | |
| 3652 | // TODO(hpayer): Process the slots buffers in parallel. This has to be done |
| 3653 | // after evacuation of all pages finishes. |
| 3654 | int buffers = evacuation_slots_buffers_.length(); |
| 3655 | for (int i = 0; i < buffers; i++) { |
| 3656 | SlotsBuffer* buffer = evacuation_slots_buffers_[i]; |
| 3657 | UpdateSlotsRecordedIn(buffer); |
| 3658 | slots_buffer_allocator_->DeallocateChain(&buffer); |
| 3659 | } |
| 3660 | evacuation_slots_buffers_.Rewind(0); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3661 | } |
| 3662 | |
| 3663 | // Second pass: find pointers to new space and update them. |
| 3664 | PointersUpdatingVisitor updating_visitor(heap()); |
| 3665 | |
| 3666 | { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3667 | GCTracer::Scope gc_scope( |
| 3668 | heap()->tracer(), GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3669 | // Update pointers in to space. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3670 | SemiSpaceIterator to_it(heap()->new_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3671 | for (HeapObject* object = to_it.Next(); object != NULL; |
| 3672 | object = to_it.Next()) { |
| 3673 | Map* map = object->map(); |
| 3674 | object->IterateBody(map->instance_type(), object->SizeFromMap(map), |
| 3675 | &updating_visitor); |
| 3676 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3677 | // Update roots. |
| 3678 | heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_SWEEP_NEWSPACE); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3679 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3680 | StoreBufferRebuildScope scope(heap_, heap_->store_buffer(), |
| 3681 | &Heap::ScavengeStoreBufferCallback); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3682 | heap_->store_buffer()->IteratePointersToNewSpace(&UpdatePointer); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3683 | } |
| 3684 | |
| 3685 | int npages = evacuation_candidates_.length(); |
| 3686 | { |
| 3687 | GCTracer::Scope gc_scope( |
| 3688 | heap()->tracer(), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3689 | GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_BETWEEN_EVACUATED); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3690 | for (int i = 0; i < npages; i++) { |
| 3691 | Page* p = evacuation_candidates_[i]; |
| 3692 | DCHECK(p->IsEvacuationCandidate() || |
| 3693 | p->IsFlagSet(Page::RESCAN_ON_EVACUATION)); |
| 3694 | |
| 3695 | if (p->IsEvacuationCandidate()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3696 | UpdateSlotsRecordedIn(p->slots_buffer()); |
| 3697 | if (FLAG_trace_fragmentation_verbose) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3698 | PrintF(" page %p slots buffer: %d\n", reinterpret_cast<void*>(p), |
| 3699 | SlotsBuffer::SizeOfChain(p->slots_buffer())); |
| 3700 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3701 | slots_buffer_allocator_->DeallocateChain(p->slots_buffer_address()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3702 | |
| 3703 | // Important: skip list should be cleared only after roots were updated |
| 3704 | // because root iteration traverses the stack and might have to find |
| 3705 | // code objects from non-updated pc pointing into evacuation candidate. |
| 3706 | SkipList* list = p->skip_list(); |
| 3707 | if (list != NULL) list->Clear(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3708 | |
| 3709 | // First pass on aborted pages, fixing up all live objects. |
| 3710 | if (p->IsFlagSet(Page::COMPACTION_WAS_ABORTED)) { |
| 3711 | p->ClearEvacuationCandidate(); |
| 3712 | VisitLiveObjectsBody(p, &updating_visitor); |
| 3713 | } |
| 3714 | } |
| 3715 | |
| 3716 | if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3717 | if (FLAG_gc_verbose) { |
| 3718 | PrintF("Sweeping 0x%" V8PRIxPTR " during evacuation.\n", |
| 3719 | reinterpret_cast<intptr_t>(p)); |
| 3720 | } |
| 3721 | PagedSpace* space = static_cast<PagedSpace*>(p->owner()); |
| 3722 | p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION); |
| 3723 | |
| 3724 | switch (space->identity()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3725 | case OLD_SPACE: |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3726 | Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD, |
| 3727 | IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p, |
| 3728 | &updating_visitor); |
| 3729 | break; |
| 3730 | case CODE_SPACE: |
| 3731 | if (FLAG_zap_code_space) { |
| 3732 | Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD, |
| 3733 | REBUILD_SKIP_LIST, ZAP_FREE_SPACE>(space, NULL, p, |
| 3734 | &updating_visitor); |
| 3735 | } else { |
| 3736 | Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD, |
| 3737 | REBUILD_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p, |
| 3738 | &updating_visitor); |
| 3739 | } |
| 3740 | break; |
| 3741 | default: |
| 3742 | UNREACHABLE(); |
| 3743 | break; |
| 3744 | } |
| 3745 | } |
| 3746 | } |
| 3747 | } |
| 3748 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3749 | { |
| 3750 | GCTracer::Scope gc_scope(heap()->tracer(), |
| 3751 | GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_WEAK); |
| 3752 | heap_->string_table()->Iterate(&updating_visitor); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3753 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3754 | // Update pointers from external string table. |
| 3755 | heap_->UpdateReferencesInExternalStringTable( |
| 3756 | &UpdateReferenceInExternalStringTableEntry); |
| 3757 | |
| 3758 | EvacuationWeakObjectRetainer evacuation_object_retainer; |
| 3759 | heap()->ProcessAllWeakReferences(&evacuation_object_retainer); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3760 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3761 | } |
| 3762 | |
| 3763 | |
| 3764 | void MarkCompactCollector::MoveEvacuationCandidatesToEndOfPagesList() { |
| 3765 | int npages = evacuation_candidates_.length(); |
| 3766 | for (int i = 0; i < npages; i++) { |
| 3767 | Page* p = evacuation_candidates_[i]; |
| 3768 | if (!p->IsEvacuationCandidate()) continue; |
| 3769 | p->Unlink(); |
| 3770 | PagedSpace* space = static_cast<PagedSpace*>(p->owner()); |
| 3771 | p->InsertAfter(space->LastPage()); |
| 3772 | } |
| 3773 | } |
| 3774 | |
| 3775 | |
| 3776 | void MarkCompactCollector::ReleaseEvacuationCandidates() { |
| 3777 | int npages = evacuation_candidates_.length(); |
| 3778 | for (int i = 0; i < npages; i++) { |
| 3779 | Page* p = evacuation_candidates_[i]; |
| 3780 | if (!p->IsEvacuationCandidate()) continue; |
| 3781 | PagedSpace* space = static_cast<PagedSpace*>(p->owner()); |
| 3782 | space->Free(p->area_start(), p->area_size()); |
| 3783 | p->set_scan_on_scavenge(false); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3784 | p->ResetLiveBytes(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3785 | CHECK(p->WasSwept()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3786 | space->ReleasePage(p); |
| 3787 | } |
| 3788 | evacuation_candidates_.Rewind(0); |
| 3789 | compacting_ = false; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3790 | heap()->FilterStoreBufferEntriesOnAboutToBeFreedPages(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3791 | heap()->FreeQueuedChunks(); |
| 3792 | } |
| 3793 | |
| 3794 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3795 | int MarkCompactCollector::SweepInParallel(PagedSpace* space, |
| 3796 | int required_freed_bytes) { |
| 3797 | int max_freed = 0; |
| 3798 | int max_freed_overall = 0; |
| 3799 | PageIterator it(space); |
| 3800 | while (it.has_next()) { |
| 3801 | Page* p = it.next(); |
| 3802 | max_freed = SweepInParallel(p, space); |
| 3803 | DCHECK(max_freed >= 0); |
| 3804 | if (required_freed_bytes > 0 && max_freed >= required_freed_bytes) { |
| 3805 | return max_freed; |
| 3806 | } |
| 3807 | max_freed_overall = Max(max_freed, max_freed_overall); |
| 3808 | if (p == space->end_of_unswept_pages()) break; |
| 3809 | } |
| 3810 | return max_freed_overall; |
| 3811 | } |
| 3812 | |
| 3813 | |
| 3814 | int MarkCompactCollector::SweepInParallel(Page* page, PagedSpace* space) { |
| 3815 | int max_freed = 0; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3816 | if (page->TryLock()) { |
| 3817 | // If this page was already swept in the meantime, we can return here. |
| 3818 | if (page->parallel_sweeping_state().Value() != |
| 3819 | MemoryChunk::kSweepingPending) { |
| 3820 | page->mutex()->Unlock(); |
| 3821 | return 0; |
| 3822 | } |
| 3823 | page->parallel_sweeping_state().SetValue(MemoryChunk::kSweepingInProgress); |
| 3824 | FreeList* free_list; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3825 | FreeList private_free_list(space); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3826 | if (space->identity() == OLD_SPACE) { |
| 3827 | free_list = free_list_old_space_.get(); |
| 3828 | max_freed = |
| 3829 | Sweep<SWEEP_ONLY, SWEEP_IN_PARALLEL, IGNORE_SKIP_LIST, |
| 3830 | IGNORE_FREE_SPACE>(space, &private_free_list, page, NULL); |
| 3831 | } else if (space->identity() == CODE_SPACE) { |
| 3832 | free_list = free_list_code_space_.get(); |
| 3833 | max_freed = |
| 3834 | Sweep<SWEEP_ONLY, SWEEP_IN_PARALLEL, REBUILD_SKIP_LIST, |
| 3835 | IGNORE_FREE_SPACE>(space, &private_free_list, page, NULL); |
| 3836 | } else { |
| 3837 | free_list = free_list_map_space_.get(); |
| 3838 | max_freed = |
| 3839 | Sweep<SWEEP_ONLY, SWEEP_IN_PARALLEL, IGNORE_SKIP_LIST, |
| 3840 | IGNORE_FREE_SPACE>(space, &private_free_list, page, NULL); |
| 3841 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3842 | free_list->Concatenate(&private_free_list); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3843 | page->mutex()->Unlock(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3844 | } |
| 3845 | return max_freed; |
| 3846 | } |
| 3847 | |
| 3848 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3849 | void MarkCompactCollector::StartSweepSpace(PagedSpace* space) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3850 | space->ClearStats(); |
| 3851 | |
| 3852 | // We defensively initialize end_of_unswept_pages_ here with the first page |
| 3853 | // of the pages list. |
| 3854 | space->set_end_of_unswept_pages(space->FirstPage()); |
| 3855 | |
| 3856 | PageIterator it(space); |
| 3857 | |
| 3858 | int pages_swept = 0; |
| 3859 | bool unused_page_present = false; |
| 3860 | bool parallel_sweeping_active = false; |
| 3861 | |
| 3862 | while (it.has_next()) { |
| 3863 | Page* p = it.next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3864 | DCHECK(p->parallel_sweeping_state().Value() == MemoryChunk::kSweepingDone); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3865 | |
| 3866 | // Clear sweeping flags indicating that marking bits are still intact. |
| 3867 | p->ClearWasSwept(); |
| 3868 | |
| 3869 | if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION) || |
| 3870 | p->IsEvacuationCandidate()) { |
| 3871 | // Will be processed in EvacuateNewSpaceAndCandidates. |
| 3872 | DCHECK(evacuation_candidates_.length() > 0); |
| 3873 | continue; |
| 3874 | } |
| 3875 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3876 | if (p->IsFlagSet(Page::NEVER_ALLOCATE_ON_PAGE)) { |
| 3877 | // We need to sweep the page to get it into an iterable state again. Note |
| 3878 | // that this adds unusable memory into the free list that is later on |
| 3879 | // (in the free list) dropped again. Since we only use the flag for |
| 3880 | // testing this is fine. |
| 3881 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST, |
| 3882 | IGNORE_FREE_SPACE>(space, nullptr, p, nullptr); |
| 3883 | continue; |
| 3884 | } |
| 3885 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3886 | // One unused page is kept, all further are released before sweeping them. |
| 3887 | if (p->LiveBytes() == 0) { |
| 3888 | if (unused_page_present) { |
| 3889 | if (FLAG_gc_verbose) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3890 | PrintIsolate(isolate(), "sweeping: released page: %p", p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3891 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3892 | space->ReleasePage(p); |
| 3893 | continue; |
| 3894 | } |
| 3895 | unused_page_present = true; |
| 3896 | } |
| 3897 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3898 | if (!parallel_sweeping_active) { |
| 3899 | if (FLAG_gc_verbose) { |
| 3900 | PrintIsolate(isolate(), "sweeping: %p", p); |
| 3901 | } |
| 3902 | if (space->identity() == CODE_SPACE) { |
| 3903 | if (FLAG_zap_code_space) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3904 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST, |
| 3905 | ZAP_FREE_SPACE>(space, NULL, p, NULL); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3906 | } else { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3907 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST, |
| 3908 | IGNORE_FREE_SPACE>(space, NULL, p, NULL); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3909 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3910 | } else { |
| 3911 | Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST, |
| 3912 | IGNORE_FREE_SPACE>(space, NULL, p, NULL); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3913 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3914 | pages_swept++; |
| 3915 | parallel_sweeping_active = true; |
| 3916 | } else { |
| 3917 | if (FLAG_gc_verbose) { |
| 3918 | PrintIsolate(isolate(), "sweeping: initialized for parallel: %p", p); |
| 3919 | } |
| 3920 | p->parallel_sweeping_state().SetValue(MemoryChunk::kSweepingPending); |
| 3921 | int to_sweep = p->area_size() - p->LiveBytes(); |
| 3922 | space->accounting_stats_.ShrinkSpace(to_sweep); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3923 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3924 | space->set_end_of_unswept_pages(p); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3925 | } |
| 3926 | |
| 3927 | if (FLAG_gc_verbose) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3928 | PrintIsolate(isolate(), "sweeping: space=%s pages_swept=%d", |
| 3929 | AllocationSpaceName(space->identity()), pages_swept); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3930 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3931 | } |
| 3932 | |
| 3933 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3934 | void MarkCompactCollector::SweepSpaces() { |
| 3935 | GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_SWEEP); |
| 3936 | double start_time = 0.0; |
| 3937 | if (FLAG_print_cumulative_gc_stat) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3938 | start_time = heap_->MonotonicallyIncreasingTimeInMs(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3939 | } |
| 3940 | |
| 3941 | #ifdef DEBUG |
| 3942 | state_ = SWEEP_SPACES; |
| 3943 | #endif |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3944 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3945 | MoveEvacuationCandidatesToEndOfPagesList(); |
| 3946 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3947 | { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 3948 | sweeping_in_progress_ = true; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3949 | { |
| 3950 | GCTracer::Scope sweep_scope(heap()->tracer(), |
| 3951 | GCTracer::Scope::MC_SWEEP_OLD); |
| 3952 | StartSweepSpace(heap()->old_space()); |
| 3953 | } |
| 3954 | { |
| 3955 | GCTracer::Scope sweep_scope(heap()->tracer(), |
| 3956 | GCTracer::Scope::MC_SWEEP_CODE); |
| 3957 | StartSweepSpace(heap()->code_space()); |
| 3958 | } |
| 3959 | { |
| 3960 | GCTracer::Scope sweep_scope(heap()->tracer(), |
| 3961 | GCTracer::Scope::MC_SWEEP_MAP); |
| 3962 | StartSweepSpace(heap()->map_space()); |
| 3963 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 3964 | if (FLAG_concurrent_sweeping) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3965 | StartSweeperThreads(); |
| 3966 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3967 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3968 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3969 | // Deallocate unmarked large objects. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3970 | heap_->lo_space()->FreeUnmarkedObjects(); |
| 3971 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3972 | // Give pages that are queued to be freed back to the OS. Invalid store |
| 3973 | // buffer entries are already filter out. We can just release the memory. |
| 3974 | heap()->FreeQueuedChunks(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3975 | |
| 3976 | if (FLAG_print_cumulative_gc_stat) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3977 | heap_->tracer()->AddSweepingTime(heap_->MonotonicallyIncreasingTimeInMs() - |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3978 | start_time); |
| 3979 | } |
| 3980 | } |
| 3981 | |
| 3982 | |
| 3983 | void MarkCompactCollector::ParallelSweepSpaceComplete(PagedSpace* space) { |
| 3984 | PageIterator it(space); |
| 3985 | while (it.has_next()) { |
| 3986 | Page* p = it.next(); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3987 | if (p->parallel_sweeping_state().Value() == |
| 3988 | MemoryChunk::kSweepingFinalize) { |
| 3989 | p->parallel_sweeping_state().SetValue(MemoryChunk::kSweepingDone); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3990 | p->SetWasSwept(); |
| 3991 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3992 | DCHECK(p->parallel_sweeping_state().Value() == MemoryChunk::kSweepingDone); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 3993 | } |
| 3994 | } |
| 3995 | |
| 3996 | |
| 3997 | void MarkCompactCollector::ParallelSweepSpacesComplete() { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 3998 | ParallelSweepSpaceComplete(heap()->old_space()); |
| 3999 | ParallelSweepSpaceComplete(heap()->code_space()); |
| 4000 | ParallelSweepSpaceComplete(heap()->map_space()); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4001 | } |
| 4002 | |
| 4003 | |
| 4004 | // TODO(1466) ReportDeleteIfNeeded is not called currently. |
| 4005 | // Our profiling tools do not expect intersections between |
| 4006 | // code objects. We should either reenable it or change our tools. |
| 4007 | void MarkCompactCollector::ReportDeleteIfNeeded(HeapObject* obj, |
| 4008 | Isolate* isolate) { |
| 4009 | if (obj->IsCode()) { |
| 4010 | PROFILE(isolate, CodeDeleteEvent(obj->address())); |
| 4011 | } |
| 4012 | } |
| 4013 | |
| 4014 | |
| 4015 | Isolate* MarkCompactCollector::isolate() const { return heap_->isolate(); } |
| 4016 | |
| 4017 | |
| 4018 | void MarkCompactCollector::Initialize() { |
| 4019 | MarkCompactMarkingVisitor::Initialize(); |
| 4020 | IncrementalMarking::Initialize(); |
| 4021 | } |
| 4022 | |
| 4023 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4024 | void MarkCompactCollector::EvictPopularEvacuationCandidate(Page* page) { |
| 4025 | if (FLAG_trace_fragmentation) { |
| 4026 | PrintF("Page %p is too popular. Disabling evacuation.\n", |
| 4027 | reinterpret_cast<void*>(page)); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4028 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4029 | |
| 4030 | isolate()->CountUsage(v8::Isolate::UseCounterFeature::kSlotsBufferOverflow); |
| 4031 | |
| 4032 | // TODO(gc) If all evacuation candidates are too popular we |
| 4033 | // should stop slots recording entirely. |
| 4034 | page->ClearEvacuationCandidate(); |
| 4035 | |
| 4036 | DCHECK(!page->IsFlagSet(Page::POPULAR_PAGE)); |
| 4037 | page->SetFlag(Page::POPULAR_PAGE); |
| 4038 | |
| 4039 | // We were not collecting slots on this page that point |
| 4040 | // to other evacuation candidates thus we have to |
| 4041 | // rescan the page after evacuation to discover and update all |
| 4042 | // pointers to evacuated objects. |
| 4043 | page->SetFlag(Page::RESCAN_ON_EVACUATION); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4044 | } |
| 4045 | |
| 4046 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4047 | void MarkCompactCollector::RecordCodeEntrySlot(HeapObject* object, Address slot, |
| 4048 | Code* target) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4049 | Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target)); |
| 4050 | if (target_page->IsEvacuationCandidate() && |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4051 | !ShouldSkipEvacuationSlotRecording(object)) { |
| 4052 | if (!SlotsBuffer::AddTo(slots_buffer_allocator_, |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4053 | target_page->slots_buffer_address(), |
| 4054 | SlotsBuffer::CODE_ENTRY_SLOT, slot, |
| 4055 | SlotsBuffer::FAIL_ON_OVERFLOW)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4056 | EvictPopularEvacuationCandidate(target_page); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4057 | } |
| 4058 | } |
| 4059 | } |
| 4060 | |
| 4061 | |
| 4062 | void MarkCompactCollector::RecordCodeTargetPatch(Address pc, Code* target) { |
| 4063 | DCHECK(heap()->gc_state() == Heap::MARK_COMPACT); |
| 4064 | if (is_compacting()) { |
| 4065 | Code* host = |
| 4066 | isolate()->inner_pointer_to_code_cache()->GcSafeFindCodeForInnerPointer( |
| 4067 | pc); |
| 4068 | MarkBit mark_bit = Marking::MarkBitFrom(host); |
| 4069 | if (Marking::IsBlack(mark_bit)) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4070 | RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 4071 | RecordRelocSlot(&rinfo, target); |
| 4072 | } |
| 4073 | } |
| 4074 | } |
| 4075 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 4076 | } // namespace internal |
| 4077 | } // namespace v8 |