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1 // Copyright 2006-2008 the V8 project authors. All rights reserved. | 1 // Copyright 2006-2008 the V8 project authors. All rights reserved. |
2 // Redistribution and use in source and binary forms, with or without | 2 // Redistribution and use in source and binary forms, with or without |
3 // modification, are permitted provided that the following conditions are | 3 // modification, are permitted provided that the following conditions are |
4 // met: | 4 // met: |
5 // | 5 // |
6 // * Redistributions of source code must retain the above copyright | 6 // * Redistributions of source code must retain the above copyright |
7 // notice, this list of conditions and the following disclaimer. | 7 // notice, this list of conditions and the following disclaimer. |
8 // * Redistributions in binary form must reproduce the above | 8 // * Redistributions in binary form must reproduce the above |
9 // copyright notice, this list of conditions and the following | 9 // copyright notice, this list of conditions and the following |
10 // disclaimer in the documentation and/or other materials provided | 10 // disclaimer in the documentation and/or other materials provided |
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59 return MemoryAllocator::GetNextPage(this); | 59 return MemoryAllocator::GetNextPage(this); |
60 } | 60 } |
61 | 61 |
62 | 62 |
63 Address Page::AllocationTop() { | 63 Address Page::AllocationTop() { |
64 PagedSpace* owner = MemoryAllocator::PageOwner(this); | 64 PagedSpace* owner = MemoryAllocator::PageOwner(this); |
65 return owner->PageAllocationTop(this); | 65 return owner->PageAllocationTop(this); |
66 } | 66 } |
67 | 67 |
68 | 68 |
69 Address Page::AllocationWatermark() { | 69 void Page::ClearRSet() { |
70 PagedSpace* owner = MemoryAllocator::PageOwner(this); | 70 // This method can be called in all rset states. |
71 if (this == owner->AllocationTopPage()) { | 71 memset(RSetStart(), 0, kRSetEndOffset - kRSetStartOffset); |
72 return owner->top(); | |
73 } | |
74 return address() + AllocationWatermarkOffset(); | |
75 } | 72 } |
76 | 73 |
77 | 74 |
78 uint32_t Page::AllocationWatermarkOffset() { | 75 // Given a 32-bit address, separate its bits into: |
79 return (flags_ & kAllocationWatermarkOffsetMask) >> | 76 // | page address | words (6) | bit offset (5) | pointer alignment (2) | |
80 kAllocationWatermarkOffsetShift; | 77 // The address of the rset word containing the bit for this word is computed as: |
| 78 // page_address + words * 4 |
| 79 // For a 64-bit address, if it is: |
| 80 // | page address | words(5) | bit offset(5) | pointer alignment (3) | |
| 81 // The address of the rset word containing the bit for this word is computed as: |
| 82 // page_address + words * 4 + kRSetOffset. |
| 83 // The rset is accessed as 32-bit words, and bit offsets in a 32-bit word, |
| 84 // even on the X64 architecture. |
| 85 |
| 86 Address Page::ComputeRSetBitPosition(Address address, int offset, |
| 87 uint32_t* bitmask) { |
| 88 ASSERT(Page::is_rset_in_use()); |
| 89 |
| 90 Page* page = Page::FromAddress(address); |
| 91 uint32_t bit_offset = ArithmeticShiftRight(page->Offset(address) + offset, |
| 92 kPointerSizeLog2); |
| 93 *bitmask = 1 << (bit_offset % kBitsPerInt); |
| 94 |
| 95 Address rset_address = |
| 96 page->address() + kRSetOffset + (bit_offset / kBitsPerInt) * kIntSize; |
| 97 // The remembered set address is either in the normal remembered set range |
| 98 // of a page or else we have a large object page. |
| 99 ASSERT((page->RSetStart() <= rset_address && rset_address < page->RSetEnd()) |
| 100 || page->IsLargeObjectPage()); |
| 101 |
| 102 if (rset_address >= page->RSetEnd()) { |
| 103 // We have a large object page, and the remembered set address is actually |
| 104 // past the end of the object. |
| 105 |
| 106 // The first part of the remembered set is still located at the start of |
| 107 // the page, but anything after kRSetEndOffset must be relocated to after |
| 108 // the large object, i.e. after |
| 109 // (page->ObjectAreaStart() + object size) |
| 110 // We do that by adding the difference between the normal RSet's end and |
| 111 // the object's end. |
| 112 ASSERT(HeapObject::FromAddress(address)->IsFixedArray()); |
| 113 int fixedarray_length = |
| 114 FixedArray::SizeFor(Memory::int_at(page->ObjectAreaStart() |
| 115 + Array::kLengthOffset)); |
| 116 rset_address += kObjectStartOffset - kRSetEndOffset + fixedarray_length; |
| 117 } |
| 118 return rset_address; |
81 } | 119 } |
82 | 120 |
83 | 121 |
84 void Page::SetAllocationWatermark(Address allocation_watermark) { | 122 void Page::SetRSet(Address address, int offset) { |
85 if ((Heap::gc_state() == Heap::SCAVENGE) && IsWatermarkValid()) { | 123 uint32_t bitmask = 0; |
86 // When iterating intergenerational references during scavenge | 124 Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask); |
87 // we might decide to promote an encountered young object. | 125 Memory::uint32_at(rset_address) |= bitmask; |
88 // We will allocate a space for such an object and put it | |
89 // into the promotion queue to process it later. | |
90 // If space for object was allocated somewhere beyond allocation | |
91 // watermark this might cause garbage pointers to appear under allocation | |
92 // watermark. To avoid visiting them during dirty regions iteration | |
93 // which might be still in progress we store a valid allocation watermark | |
94 // value and mark this page as having an invalid watermark. | |
95 SetCachedAllocationWatermark(AllocationWatermark()); | |
96 InvalidateWatermark(true); | |
97 } | |
98 | 126 |
99 flags_ = (flags_ & kFlagsMask) | | 127 ASSERT(IsRSetSet(address, offset)); |
100 Offset(allocation_watermark) << kAllocationWatermarkOffsetShift; | |
101 ASSERT(AllocationWatermarkOffset() | |
102 == static_cast<uint32_t>(Offset(allocation_watermark))); | |
103 } | 128 } |
104 | 129 |
105 | 130 |
106 void Page::SetCachedAllocationWatermark(Address allocation_watermark) { | 131 // Clears the corresponding remembered set bit for a given address. |
107 mc_first_forwarded = allocation_watermark; | 132 void Page::UnsetRSet(Address address, int offset) { |
| 133 uint32_t bitmask = 0; |
| 134 Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask); |
| 135 Memory::uint32_at(rset_address) &= ~bitmask; |
| 136 |
| 137 ASSERT(!IsRSetSet(address, offset)); |
108 } | 138 } |
109 | 139 |
110 | 140 |
111 Address Page::CachedAllocationWatermark() { | 141 bool Page::IsRSetSet(Address address, int offset) { |
112 return mc_first_forwarded; | |
113 } | |
114 | |
115 | |
116 uint32_t Page::GetRegionMarks() { | |
117 return dirty_regions_; | |
118 } | |
119 | |
120 | |
121 void Page::SetRegionMarks(uint32_t marks) { | |
122 dirty_regions_ = marks; | |
123 } | |
124 | |
125 | |
126 int Page::GetRegionNumberForAddress(Address addr) { | |
127 // Each page is divided into 256 byte regions. Each region has a corresponding | |
128 // dirty mark bit in the page header. Region can contain intergenerational | |
129 // references iff its dirty mark is set. | |
130 // A normal 8K page contains exactly 32 regions so all region marks fit | |
131 // into 32-bit integer field. To calculate a region number we just divide | |
132 // offset inside page by region size. | |
133 // A large page can contain more then 32 regions. But we want to avoid | |
134 // additional write barrier code for distinguishing between large and normal | |
135 // pages so we just ignore the fact that addr points into a large page and | |
136 // calculate region number as if addr pointed into a normal 8K page. This way | |
137 // we get a region number modulo 32 so for large pages several regions might | |
138 // be mapped to a single dirty mark. | |
139 ASSERT_PAGE_ALIGNED(this->address()); | |
140 STATIC_ASSERT((kPageAlignmentMask >> kRegionSizeLog2) < kBitsPerInt); | |
141 | |
142 // We are using masking with kPageAlignmentMask instead of Page::Offset() | |
143 // to get an offset to the beginning of 8K page containing addr not to the | |
144 // beginning of actual page which can be bigger then 8K. | |
145 return (OffsetFrom(addr) & kPageAlignmentMask) >> kRegionSizeLog2; | |
146 } | |
147 | |
148 | |
149 uint32_t Page::GetRegionMaskForAddress(Address addr) { | |
150 return 1 << GetRegionNumberForAddress(addr); | |
151 } | |
152 | |
153 | |
154 void Page::MarkRegionDirty(Address address) { | |
155 SetRegionMarks(GetRegionMarks() | GetRegionMaskForAddress(address)); | |
156 } | |
157 | |
158 | |
159 bool Page::IsRegionDirty(Address address) { | |
160 return GetRegionMarks() & GetRegionMaskForAddress(address); | |
161 } | |
162 | |
163 | |
164 void Page::ClearRegionMarks(Address start, Address end, bool reaches_limit) { | |
165 int rstart = GetRegionNumberForAddress(start); | |
166 int rend = GetRegionNumberForAddress(end); | |
167 | |
168 if (reaches_limit) { | |
169 end += 1; | |
170 } | |
171 | |
172 if ((rend - rstart) == 0) { | |
173 return; | |
174 } | |
175 | |
176 uint32_t bitmask = 0; | 142 uint32_t bitmask = 0; |
177 | 143 Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask); |
178 if ((OffsetFrom(start) & kRegionAlignmentMask) == 0 | 144 return (Memory::uint32_at(rset_address) & bitmask) != 0; |
179 || (start == ObjectAreaStart())) { | |
180 // First region is fully covered | |
181 bitmask = 1 << rstart; | |
182 } | |
183 | |
184 while (++rstart < rend) { | |
185 bitmask |= 1 << rstart; | |
186 } | |
187 | |
188 if (bitmask) { | |
189 SetRegionMarks(GetRegionMarks() & ~bitmask); | |
190 } | |
191 } | |
192 | |
193 | |
194 void Page::FlipMeaningOfInvalidatedWatermarkFlag() { | |
195 watermark_invalidated_mark_ ^= WATERMARK_INVALIDATED; | |
196 } | |
197 | |
198 | |
199 bool Page::IsWatermarkValid() { | |
200 return (flags_ & WATERMARK_INVALIDATED) != watermark_invalidated_mark_; | |
201 } | |
202 | |
203 | |
204 void Page::InvalidateWatermark(bool value) { | |
205 if (value) { | |
206 flags_ = (flags_ & ~WATERMARK_INVALIDATED) | watermark_invalidated_mark_; | |
207 } else { | |
208 flags_ = (flags_ & ~WATERMARK_INVALIDATED) | | |
209 (watermark_invalidated_mark_ ^ WATERMARK_INVALIDATED); | |
210 } | |
211 | |
212 ASSERT(IsWatermarkValid() == !value); | |
213 } | 145 } |
214 | 146 |
215 | 147 |
216 bool Page::GetPageFlag(PageFlag flag) { | 148 bool Page::GetPageFlag(PageFlag flag) { |
217 return (flags_ & flag) != 0; | 149 return (flags & flag) != 0; |
218 } | 150 } |
219 | 151 |
220 | 152 |
221 void Page::SetPageFlag(PageFlag flag, bool value) { | 153 void Page::SetPageFlag(PageFlag flag, bool value) { |
222 if (value) { | 154 if (value) { |
223 flags_ |= flag; | 155 flags |= flag; |
224 } else { | 156 } else { |
225 flags_ &= ~flag; | 157 flags &= ~flag; |
226 } | 158 } |
227 } | 159 } |
228 | 160 |
229 | 161 |
230 void Page::ClearPageFlags() { | |
231 flags_ = 0; | |
232 } | |
233 | |
234 | |
235 bool Page::WasInUseBeforeMC() { | 162 bool Page::WasInUseBeforeMC() { |
236 return GetPageFlag(WAS_IN_USE_BEFORE_MC); | 163 return GetPageFlag(WAS_IN_USE_BEFORE_MC); |
237 } | 164 } |
238 | 165 |
239 | 166 |
240 void Page::SetWasInUseBeforeMC(bool was_in_use) { | 167 void Page::SetWasInUseBeforeMC(bool was_in_use) { |
241 SetPageFlag(WAS_IN_USE_BEFORE_MC, was_in_use); | 168 SetPageFlag(WAS_IN_USE_BEFORE_MC, was_in_use); |
242 } | 169 } |
243 | 170 |
244 | 171 |
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409 // Round the chunk address up to the nearest page-aligned address | 336 // Round the chunk address up to the nearest page-aligned address |
410 // and return the heap object in that page. | 337 // and return the heap object in that page. |
411 Page* page = Page::FromAddress(RoundUp(address(), Page::kPageSize)); | 338 Page* page = Page::FromAddress(RoundUp(address(), Page::kPageSize)); |
412 return HeapObject::FromAddress(page->ObjectAreaStart()); | 339 return HeapObject::FromAddress(page->ObjectAreaStart()); |
413 } | 340 } |
414 | 341 |
415 | 342 |
416 // ----------------------------------------------------------------------------- | 343 // ----------------------------------------------------------------------------- |
417 // LargeObjectSpace | 344 // LargeObjectSpace |
418 | 345 |
| 346 int LargeObjectSpace::ExtraRSetBytesFor(int object_size) { |
| 347 int extra_rset_bits = |
| 348 RoundUp((object_size - Page::kObjectAreaSize) / kPointerSize, |
| 349 kBitsPerInt); |
| 350 return extra_rset_bits / kBitsPerByte; |
| 351 } |
| 352 |
| 353 |
419 Object* NewSpace::AllocateRawInternal(int size_in_bytes, | 354 Object* NewSpace::AllocateRawInternal(int size_in_bytes, |
420 AllocationInfo* alloc_info) { | 355 AllocationInfo* alloc_info) { |
421 Address new_top = alloc_info->top + size_in_bytes; | 356 Address new_top = alloc_info->top + size_in_bytes; |
422 if (new_top > alloc_info->limit) return Failure::RetryAfterGC(size_in_bytes); | 357 if (new_top > alloc_info->limit) return Failure::RetryAfterGC(size_in_bytes); |
423 | 358 |
424 Object* obj = HeapObject::FromAddress(alloc_info->top); | 359 Object* obj = HeapObject::FromAddress(alloc_info->top); |
425 alloc_info->top = new_top; | 360 alloc_info->top = new_top; |
426 #ifdef DEBUG | 361 #ifdef DEBUG |
427 SemiSpace* space = | 362 SemiSpace* space = |
428 (alloc_info == &allocation_info_) ? &to_space_ : &from_space_; | 363 (alloc_info == &allocation_info_) ? &to_space_ : &from_space_; |
429 ASSERT(space->low() <= alloc_info->top | 364 ASSERT(space->low() <= alloc_info->top |
430 && alloc_info->top <= space->high() | 365 && alloc_info->top <= space->high() |
431 && alloc_info->limit == space->high()); | 366 && alloc_info->limit == space->high()); |
432 #endif | 367 #endif |
433 return obj; | 368 return obj; |
434 } | 369 } |
435 | 370 |
436 | 371 |
437 bool FreeListNode::IsFreeListNode(HeapObject* object) { | 372 bool FreeListNode::IsFreeListNode(HeapObject* object) { |
438 return object->map() == Heap::raw_unchecked_byte_array_map() | 373 return object->map() == Heap::raw_unchecked_byte_array_map() |
439 || object->map() == Heap::raw_unchecked_one_pointer_filler_map() | 374 || object->map() == Heap::raw_unchecked_one_pointer_filler_map() |
440 || object->map() == Heap::raw_unchecked_two_pointer_filler_map(); | 375 || object->map() == Heap::raw_unchecked_two_pointer_filler_map(); |
441 } | 376 } |
442 | 377 |
443 } } // namespace v8::internal | 378 } } // namespace v8::internal |
444 | 379 |
445 #endif // V8_SPACES_INL_H_ | 380 #endif // V8_SPACES_INL_H_ |
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