// Copyright 2011 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "v8.h" #include "liveobjectlist-inl.h" #include "macro-assembler.h" #include "mark-compact.h" #include "platform.h" namespace v8 { namespace internal { // For contiguous spaces, top should be in the space (or at the end) and limit // should be the end of the space. #define ASSERT_SEMISPACE_ALLOCATION_INFO(info, space) \ ASSERT((space).low() <= (info).top \ && (info).top <= (space).high() \ && (info).limit == (space).high()) // ---------------------------------------------------------------------------- // HeapObjectIterator HeapObjectIterator::HeapObjectIterator(PagedSpace* space) { Initialize(space->bottom(), space->top(), NULL); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, HeapObjectCallback size_func) { Initialize(space->bottom(), space->top(), size_func); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start) { Initialize(start, space->top(), NULL); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start, HeapObjectCallback size_func) { Initialize(start, space->top(), size_func); } HeapObjectIterator::HeapObjectIterator(Page* page, HeapObjectCallback size_func) { Initialize(page->ObjectAreaStart(), page->AllocationTop(), size_func); } void HeapObjectIterator::Initialize(Address cur, Address end, HeapObjectCallback size_f) { cur_addr_ = cur; end_addr_ = end; end_page_ = Page::FromAllocationTop(end); size_func_ = size_f; Page* p = Page::FromAllocationTop(cur_addr_); cur_limit_ = (p == end_page_) ? end_addr_ : p->AllocationTop(); #ifdef DEBUG Verify(); #endif } HeapObject* HeapObjectIterator::FromNextPage() { if (cur_addr_ == end_addr_) return NULL; Page* cur_page = Page::FromAllocationTop(cur_addr_); cur_page = cur_page->next_page(); ASSERT(cur_page->is_valid()); cur_addr_ = cur_page->ObjectAreaStart(); cur_limit_ = (cur_page == end_page_) ? end_addr_ : cur_page->AllocationTop(); if (cur_addr_ == end_addr_) return NULL; ASSERT(cur_addr_ < cur_limit_); #ifdef DEBUG Verify(); #endif return FromCurrentPage(); } #ifdef DEBUG void HeapObjectIterator::Verify() { Page* p = Page::FromAllocationTop(cur_addr_); ASSERT(p == Page::FromAllocationTop(cur_limit_)); ASSERT(p->Offset(cur_addr_) <= p->Offset(cur_limit_)); } #endif // ----------------------------------------------------------------------------- // PageIterator PageIterator::PageIterator(PagedSpace* space, Mode mode) : space_(space) { prev_page_ = NULL; switch (mode) { case PAGES_IN_USE: stop_page_ = space->AllocationTopPage(); break; case PAGES_USED_BY_MC: stop_page_ = space->MCRelocationTopPage(); break; case ALL_PAGES: #ifdef DEBUG // Verify that the cached last page in the space is actually the // last page. for (Page* p = space->first_page_; p->is_valid(); p = p->next_page()) { if (!p->next_page()->is_valid()) { ASSERT(space->last_page_ == p); } } #endif stop_page_ = space->last_page_; break; } } // ----------------------------------------------------------------------------- // CodeRange CodeRange::CodeRange(Isolate* isolate) : isolate_(isolate), code_range_(NULL), free_list_(0), allocation_list_(0), current_allocation_block_index_(0) { } bool CodeRange::Setup(const size_t requested) { ASSERT(code_range_ == NULL); code_range_ = new VirtualMemory(requested); CHECK(code_range_ != NULL); if (!code_range_->IsReserved()) { delete code_range_; code_range_ = NULL; return false; } // We are sure that we have mapped a block of requested addresses. ASSERT(code_range_->size() == requested); LOG(isolate_, NewEvent("CodeRange", code_range_->address(), requested)); allocation_list_.Add(FreeBlock(code_range_->address(), code_range_->size())); current_allocation_block_index_ = 0; return true; } int CodeRange::CompareFreeBlockAddress(const FreeBlock* left, const FreeBlock* right) { // The entire point of CodeRange is that the difference between two // addresses in the range can be represented as a signed 32-bit int, // so the cast is semantically correct. return static_cast(left->start - right->start); } void CodeRange::GetNextAllocationBlock(size_t requested) { for (current_allocation_block_index_++; current_allocation_block_index_ < allocation_list_.length(); current_allocation_block_index_++) { if (requested <= allocation_list_[current_allocation_block_index_].size) { return; // Found a large enough allocation block. } } // Sort and merge the free blocks on the free list and the allocation list. free_list_.AddAll(allocation_list_); allocation_list_.Clear(); free_list_.Sort(&CompareFreeBlockAddress); for (int i = 0; i < free_list_.length();) { FreeBlock merged = free_list_[i]; i++; // Add adjacent free blocks to the current merged block. while (i < free_list_.length() && free_list_[i].start == merged.start + merged.size) { merged.size += free_list_[i].size; i++; } if (merged.size > 0) { allocation_list_.Add(merged); } } free_list_.Clear(); for (current_allocation_block_index_ = 0; current_allocation_block_index_ < allocation_list_.length(); current_allocation_block_index_++) { if (requested <= allocation_list_[current_allocation_block_index_].size) { return; // Found a large enough allocation block. } } // Code range is full or too fragmented. V8::FatalProcessOutOfMemory("CodeRange::GetNextAllocationBlock"); } void* CodeRange::AllocateRawMemory(const size_t requested, size_t* allocated) { ASSERT(current_allocation_block_index_ < allocation_list_.length()); if (requested > allocation_list_[current_allocation_block_index_].size) { // Find an allocation block large enough. This function call may // call V8::FatalProcessOutOfMemory if it cannot find a large enough block. GetNextAllocationBlock(requested); } // Commit the requested memory at the start of the current allocation block. *allocated = RoundUp(requested, Page::kPageSize); FreeBlock current = allocation_list_[current_allocation_block_index_]; if (*allocated >= current.size - Page::kPageSize) { // Don't leave a small free block, useless for a large object or chunk. *allocated = current.size; } ASSERT(*allocated <= current.size); if (!code_range_->Commit(current.start, *allocated, true)) { *allocated = 0; return NULL; } allocation_list_[current_allocation_block_index_].start += *allocated; allocation_list_[current_allocation_block_index_].size -= *allocated; if (*allocated == current.size) { GetNextAllocationBlock(0); // This block is used up, get the next one. } return current.start; } void CodeRange::FreeRawMemory(void* address, size_t length) { free_list_.Add(FreeBlock(address, length)); code_range_->Uncommit(address, length); } void CodeRange::TearDown() { delete code_range_; // Frees all memory in the virtual memory range. code_range_ = NULL; free_list_.Free(); allocation_list_.Free(); } // ----------------------------------------------------------------------------- // MemoryAllocator // // 270 is an estimate based on the static default heap size of a pair of 256K // semispaces and a 64M old generation. const int kEstimatedNumberOfChunks = 270; MemoryAllocator::MemoryAllocator(Isolate* isolate) : isolate_(isolate), capacity_(0), capacity_executable_(0), size_(0), size_executable_(0), initial_chunk_(NULL), chunks_(kEstimatedNumberOfChunks), free_chunk_ids_(kEstimatedNumberOfChunks), max_nof_chunks_(0), top_(0) { } void MemoryAllocator::Push(int free_chunk_id) { ASSERT(max_nof_chunks_ > 0); ASSERT(top_ < max_nof_chunks_); free_chunk_ids_[top_++] = free_chunk_id; } int MemoryAllocator::Pop() { ASSERT(top_ > 0); return free_chunk_ids_[--top_]; } bool MemoryAllocator::Setup(intptr_t capacity, intptr_t capacity_executable) { capacity_ = RoundUp(capacity, Page::kPageSize); capacity_executable_ = RoundUp(capacity_executable, Page::kPageSize); ASSERT_GE(capacity_, capacity_executable_); // Over-estimate the size of chunks_ array. It assumes the expansion of old // space is always in the unit of a chunk (kChunkSize) except the last // expansion. // // Due to alignment, allocated space might be one page less than required // number (kPagesPerChunk) of pages for old spaces. // // Reserve two chunk ids for semispaces, one for map space, one for old // space, and one for code space. max_nof_chunks_ = static_cast((capacity_ / (kChunkSize - Page::kPageSize))) + 5; if (max_nof_chunks_ > kMaxNofChunks) return false; size_ = 0; size_executable_ = 0; ChunkInfo info; // uninitialized element. for (int i = max_nof_chunks_ - 1; i >= 0; i--) { chunks_.Add(info); free_chunk_ids_.Add(i); } top_ = max_nof_chunks_; return true; } void MemoryAllocator::TearDown() { for (int i = 0; i < max_nof_chunks_; i++) { if (chunks_[i].address() != NULL) DeleteChunk(i); } chunks_.Clear(); free_chunk_ids_.Clear(); if (initial_chunk_ != NULL) { LOG(isolate_, DeleteEvent("InitialChunk", initial_chunk_->address())); delete initial_chunk_; initial_chunk_ = NULL; } ASSERT(top_ == max_nof_chunks_); // all chunks are free top_ = 0; capacity_ = 0; capacity_executable_ = 0; size_ = 0; max_nof_chunks_ = 0; } void* MemoryAllocator::AllocateRawMemory(const size_t requested, size_t* allocated, Executability executable) { if (size_ + static_cast(requested) > static_cast(capacity_)) { return NULL; } void* mem; if (executable == EXECUTABLE) { // Check executable memory limit. if (size_executable_ + requested > static_cast(capacity_executable_)) { LOG(isolate_, StringEvent("MemoryAllocator::AllocateRawMemory", "V8 Executable Allocation capacity exceeded")); return NULL; } // Allocate executable memory either from code range or from the // OS. if (isolate_->code_range()->exists()) { mem = isolate_->code_range()->AllocateRawMemory(requested, allocated); } else { mem = OS::Allocate(requested, allocated, true); } // Update executable memory size. size_executable_ += static_cast(*allocated); } else { mem = OS::Allocate(requested, allocated, false); } int alloced = static_cast(*allocated); size_ += alloced; #ifdef DEBUG ZapBlock(reinterpret_cast
(mem), alloced); #endif isolate_->counters()->memory_allocated()->Increment(alloced); return mem; } void MemoryAllocator::FreeRawMemory(void* mem, size_t length, Executability executable) { #ifdef DEBUG // Do not try to zap the guard page. size_t guard_size = (executable == EXECUTABLE) ? Page::kPageSize : 0; ZapBlock(reinterpret_cast
(mem) + guard_size, length - guard_size); #endif if (isolate_->code_range()->contains(static_cast
(mem))) { isolate_->code_range()->FreeRawMemory(mem, length); } else { OS::Free(mem, length); } isolate_->counters()->memory_allocated()->Decrement(static_cast(length)); size_ -= static_cast(length); if (executable == EXECUTABLE) size_executable_ -= static_cast(length); ASSERT(size_ >= 0); ASSERT(size_executable_ >= 0); } void MemoryAllocator::PerformAllocationCallback(ObjectSpace space, AllocationAction action, size_t size) { for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) { MemoryAllocationCallbackRegistration registration = memory_allocation_callbacks_[i]; if ((registration.space & space) == space && (registration.action & action) == action) registration.callback(space, action, static_cast(size)); } } bool MemoryAllocator::MemoryAllocationCallbackRegistered( MemoryAllocationCallback callback) { for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) { if (memory_allocation_callbacks_[i].callback == callback) return true; } return false; } void MemoryAllocator::AddMemoryAllocationCallback( MemoryAllocationCallback callback, ObjectSpace space, AllocationAction action) { ASSERT(callback != NULL); MemoryAllocationCallbackRegistration registration(callback, space, action); ASSERT(!MemoryAllocator::MemoryAllocationCallbackRegistered(callback)); return memory_allocation_callbacks_.Add(registration); } void MemoryAllocator::RemoveMemoryAllocationCallback( MemoryAllocationCallback callback) { ASSERT(callback != NULL); for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) { if (memory_allocation_callbacks_[i].callback == callback) { memory_allocation_callbacks_.Remove(i); return; } } UNREACHABLE(); } void* MemoryAllocator::ReserveInitialChunk(const size_t requested) { ASSERT(initial_chunk_ == NULL); initial_chunk_ = new VirtualMemory(requested); CHECK(initial_chunk_ != NULL); if (!initial_chunk_->IsReserved()) { delete initial_chunk_; initial_chunk_ = NULL; return NULL; } // We are sure that we have mapped a block of requested addresses. ASSERT(initial_chunk_->size() == requested); LOG(isolate_, NewEvent("InitialChunk", initial_chunk_->address(), requested)); size_ += static_cast(requested); return initial_chunk_->address(); } static int PagesInChunk(Address start, size_t size) { // The first page starts on the first page-aligned address from start onward // and the last page ends on the last page-aligned address before // start+size. Page::kPageSize is a power of two so we can divide by // shifting. return static_cast((RoundDown(start + size, Page::kPageSize) - RoundUp(start, Page::kPageSize)) >> kPageSizeBits); } Page* MemoryAllocator::AllocatePages(int requested_pages, int* allocated_pages, PagedSpace* owner) { if (requested_pages <= 0) return Page::FromAddress(NULL); size_t chunk_size = requested_pages * Page::kPageSize; void* chunk = AllocateRawMemory(chunk_size, &chunk_size, owner->executable()); if (chunk == NULL) return Page::FromAddress(NULL); LOG(isolate_, NewEvent("PagedChunk", chunk, chunk_size)); *allocated_pages = PagesInChunk(static_cast
(chunk), chunk_size); // We may 'lose' a page due to alignment. ASSERT(*allocated_pages >= kPagesPerChunk - 1); size_t guard_size = (owner->executable() == EXECUTABLE) ? Page::kPageSize : 0; // Check that we got at least one page that we can use. if (*allocated_pages <= ((guard_size != 0) ? 1 : 0)) { FreeRawMemory(chunk, chunk_size, owner->executable()); LOG(isolate_, DeleteEvent("PagedChunk", chunk)); return Page::FromAddress(NULL); } if (guard_size != 0) { OS::Guard(chunk, guard_size); chunk_size -= guard_size; chunk = static_cast
(chunk) + guard_size; --*allocated_pages; } int chunk_id = Pop(); chunks_[chunk_id].init(static_cast
(chunk), chunk_size, owner); ObjectSpace space = static_cast(1 << owner->identity()); PerformAllocationCallback(space, kAllocationActionAllocate, chunk_size); Page* new_pages = InitializePagesInChunk(chunk_id, *allocated_pages, owner); return new_pages; } Page* MemoryAllocator::CommitPages(Address start, size_t size, PagedSpace* owner, int* num_pages) { ASSERT(start != NULL); *num_pages = PagesInChunk(start, size); ASSERT(*num_pages > 0); ASSERT(initial_chunk_ != NULL); ASSERT(InInitialChunk(start)); ASSERT(InInitialChunk(start + size - 1)); if (!initial_chunk_->Commit(start, size, owner->executable() == EXECUTABLE)) { return Page::FromAddress(NULL); } #ifdef DEBUG ZapBlock(start, size); #endif isolate_->counters()->memory_allocated()->Increment(static_cast(size)); // So long as we correctly overestimated the number of chunks we should not // run out of chunk ids. CHECK(!OutOfChunkIds()); int chunk_id = Pop(); chunks_[chunk_id].init(start, size, owner); return InitializePagesInChunk(chunk_id, *num_pages, owner); } bool MemoryAllocator::CommitBlock(Address start, size_t size, Executability executable) { ASSERT(start != NULL); ASSERT(size > 0); ASSERT(initial_chunk_ != NULL); ASSERT(InInitialChunk(start)); ASSERT(InInitialChunk(start + size - 1)); if (!initial_chunk_->Commit(start, size, executable)) return false; #ifdef DEBUG ZapBlock(start, size); #endif isolate_->counters()->memory_allocated()->Increment(static_cast(size)); return true; } bool MemoryAllocator::UncommitBlock(Address start, size_t size) { ASSERT(start != NULL); ASSERT(size > 0); ASSERT(initial_chunk_ != NULL); ASSERT(InInitialChunk(start)); ASSERT(InInitialChunk(start + size - 1)); if (!initial_chunk_->Uncommit(start, size)) return false; isolate_->counters()->memory_allocated()->Decrement(static_cast(size)); return true; } void MemoryAllocator::ZapBlock(Address start, size_t size) { for (size_t s = 0; s + kPointerSize <= size; s += kPointerSize) { Memory::Address_at(start + s) = kZapValue; } } Page* MemoryAllocator::InitializePagesInChunk(int chunk_id, int pages_in_chunk, PagedSpace* owner) { ASSERT(IsValidChunk(chunk_id)); ASSERT(pages_in_chunk > 0); Address chunk_start = chunks_[chunk_id].address(); Address low = RoundUp(chunk_start, Page::kPageSize); #ifdef DEBUG size_t chunk_size = chunks_[chunk_id].size(); Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize); ASSERT(pages_in_chunk <= ((OffsetFrom(high) - OffsetFrom(low)) / Page::kPageSize)); #endif Address page_addr = low; for (int i = 0; i < pages_in_chunk; i++) { Page* p = Page::FromAddress(page_addr); p->heap_ = owner->heap(); p->opaque_header = OffsetFrom(page_addr + Page::kPageSize) | chunk_id; p->InvalidateWatermark(true); p->SetIsLargeObjectPage(false); p->SetAllocationWatermark(p->ObjectAreaStart()); p->SetCachedAllocationWatermark(p->ObjectAreaStart()); page_addr += Page::kPageSize; } // Set the next page of the last page to 0. Page* last_page = Page::FromAddress(page_addr - Page::kPageSize); last_page->opaque_header = OffsetFrom(0) | chunk_id; return Page::FromAddress(low); } Page* MemoryAllocator::FreePages(Page* p) { if (!p->is_valid()) return p; // Find the first page in the same chunk as 'p' Page* first_page = FindFirstPageInSameChunk(p); Page* page_to_return = Page::FromAddress(NULL); if (p != first_page) { // Find the last page in the same chunk as 'prev'. Page* last_page = FindLastPageInSameChunk(p); first_page = GetNextPage(last_page); // first page in next chunk // set the next_page of last_page to NULL SetNextPage(last_page, Page::FromAddress(NULL)); page_to_return = p; // return 'p' when exiting } while (first_page->is_valid()) { int chunk_id = GetChunkId(first_page); ASSERT(IsValidChunk(chunk_id)); // Find the first page of the next chunk before deleting this chunk. first_page = GetNextPage(FindLastPageInSameChunk(first_page)); // Free the current chunk. DeleteChunk(chunk_id); } return page_to_return; } void MemoryAllocator::FreeAllPages(PagedSpace* space) { for (int i = 0, length = chunks_.length(); i < length; i++) { if (chunks_[i].owner() == space) { DeleteChunk(i); } } } void MemoryAllocator::DeleteChunk(int chunk_id) { ASSERT(IsValidChunk(chunk_id)); ChunkInfo& c = chunks_[chunk_id]; // We cannot free a chunk contained in the initial chunk because it was not // allocated with AllocateRawMemory. Instead we uncommit the virtual // memory. if (InInitialChunk(c.address())) { // TODO(1240712): VirtualMemory::Uncommit has a return value which // is ignored here. initial_chunk_->Uncommit(c.address(), c.size()); Counters* counters = isolate_->counters(); counters->memory_allocated()->Decrement(static_cast(c.size())); } else { LOG(isolate_, DeleteEvent("PagedChunk", c.address())); ObjectSpace space = static_cast(1 << c.owner_identity()); size_t size = c.size(); size_t guard_size = (c.executable() == EXECUTABLE) ? Page::kPageSize : 0; FreeRawMemory(c.address() - guard_size, size + guard_size, c.executable()); PerformAllocationCallback(space, kAllocationActionFree, size); } c.init(NULL, 0, NULL); Push(chunk_id); } Page* MemoryAllocator::FindFirstPageInSameChunk(Page* p) { int chunk_id = GetChunkId(p); ASSERT(IsValidChunk(chunk_id)); Address low = RoundUp(chunks_[chunk_id].address(), Page::kPageSize); return Page::FromAddress(low); } Page* MemoryAllocator::FindLastPageInSameChunk(Page* p) { int chunk_id = GetChunkId(p); ASSERT(IsValidChunk(chunk_id)); Address chunk_start = chunks_[chunk_id].address(); size_t chunk_size = chunks_[chunk_id].size(); Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize); ASSERT(chunk_start <= p->address() && p->address() < high); return Page::FromAddress(high - Page::kPageSize); } #ifdef DEBUG void MemoryAllocator::ReportStatistics() { float pct = static_cast(capacity_ - size_) / capacity_; PrintF(" capacity: %" V8_PTR_PREFIX "d" ", used: %" V8_PTR_PREFIX "d" ", available: %%%d\n\n", capacity_, size_, static_cast(pct*100)); } #endif void MemoryAllocator::RelinkPageListInChunkOrder(PagedSpace* space, Page** first_page, Page** last_page, Page** last_page_in_use) { Page* first = NULL; Page* last = NULL; for (int i = 0, length = chunks_.length(); i < length; i++) { ChunkInfo& chunk = chunks_[i]; if (chunk.owner() == space) { if (first == NULL) { Address low = RoundUp(chunk.address(), Page::kPageSize); first = Page::FromAddress(low); } last = RelinkPagesInChunk(i, chunk.address(), chunk.size(), last, last_page_in_use); } } if (first_page != NULL) { *first_page = first; } if (last_page != NULL) { *last_page = last; } } Page* MemoryAllocator::RelinkPagesInChunk(int chunk_id, Address chunk_start, size_t chunk_size, Page* prev, Page** last_page_in_use) { Address page_addr = RoundUp(chunk_start, Page::kPageSize); int pages_in_chunk = PagesInChunk(chunk_start, chunk_size); if (prev->is_valid()) { SetNextPage(prev, Page::FromAddress(page_addr)); } for (int i = 0; i < pages_in_chunk; i++) { Page* p = Page::FromAddress(page_addr); p->opaque_header = OffsetFrom(page_addr + Page::kPageSize) | chunk_id; page_addr += Page::kPageSize; p->InvalidateWatermark(true); if (p->WasInUseBeforeMC()) { *last_page_in_use = p; } } // Set the next page of the last page to 0. Page* last_page = Page::FromAddress(page_addr - Page::kPageSize); last_page->opaque_header = OffsetFrom(0) | chunk_id; if (last_page->WasInUseBeforeMC()) { *last_page_in_use = last_page; } return last_page; } // ----------------------------------------------------------------------------- // PagedSpace implementation PagedSpace::PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id, Executability executable) : Space(heap, id, executable) { max_capacity_ = (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize) * Page::kObjectAreaSize; accounting_stats_.Clear(); allocation_info_.top = NULL; allocation_info_.limit = NULL; mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; } bool PagedSpace::Setup(Address start, size_t size) { if (HasBeenSetup()) return false; int num_pages = 0; // Try to use the virtual memory range passed to us. If it is too small to // contain at least one page, ignore it and allocate instead. int pages_in_chunk = PagesInChunk(start, size); if (pages_in_chunk > 0) { first_page_ = Isolate::Current()->memory_allocator()->CommitPages( RoundUp(start, Page::kPageSize), Page::kPageSize * pages_in_chunk, this, &num_pages); } else { int requested_pages = Min(MemoryAllocator::kPagesPerChunk, static_cast(max_capacity_ / Page::kObjectAreaSize)); first_page_ = Isolate::Current()->memory_allocator()->AllocatePages( requested_pages, &num_pages, this); if (!first_page_->is_valid()) return false; } // We are sure that the first page is valid and that we have at least one // page. ASSERT(first_page_->is_valid()); ASSERT(num_pages > 0); accounting_stats_.ExpandSpace(num_pages * Page::kObjectAreaSize); ASSERT(Capacity() <= max_capacity_); // Sequentially clear region marks in the newly allocated // pages and cache the current last page in the space. for (Page* p = first_page_; p->is_valid(); p = p->next_page()) { p->SetRegionMarks(Page::kAllRegionsCleanMarks); last_page_ = p; } // Use first_page_ for allocation. SetAllocationInfo(&allocation_info_, first_page_); page_list_is_chunk_ordered_ = true; return true; } bool PagedSpace::HasBeenSetup() { return (Capacity() > 0); } void PagedSpace::TearDown() { Isolate::Current()->memory_allocator()->FreeAllPages(this); first_page_ = NULL; accounting_stats_.Clear(); } void PagedSpace::MarkAllPagesClean() { PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { it.next()->SetRegionMarks(Page::kAllRegionsCleanMarks); } } MaybeObject* PagedSpace::FindObject(Address addr) { // Note: this function can only be called before or after mark-compact GC // because it accesses map pointers. ASSERT(!heap()->mark_compact_collector()->in_use()); if (!Contains(addr)) return Failure::Exception(); Page* p = Page::FromAddress(addr); ASSERT(IsUsed(p)); Address cur = p->ObjectAreaStart(); Address end = p->AllocationTop(); while (cur < end) { HeapObject* obj = HeapObject::FromAddress(cur); Address next = cur + obj->Size(); if ((cur <= addr) && (addr < next)) return obj; cur = next; } UNREACHABLE(); return Failure::Exception(); } bool PagedSpace::IsUsed(Page* page) { PageIterator it(this, PageIterator::PAGES_IN_USE); while (it.has_next()) { if (page == it.next()) return true; } return false; } void PagedSpace::SetAllocationInfo(AllocationInfo* alloc_info, Page* p) { alloc_info->top = p->ObjectAreaStart(); alloc_info->limit = p->ObjectAreaEnd(); ASSERT(alloc_info->VerifyPagedAllocation()); } void PagedSpace::MCResetRelocationInfo() { // Set page indexes. int i = 0; PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { Page* p = it.next(); p->mc_page_index = i++; } // Set mc_forwarding_info_ to the first page in the space. SetAllocationInfo(&mc_forwarding_info_, first_page_); // All the bytes in the space are 'available'. We will rediscover // allocated and wasted bytes during GC. accounting_stats_.Reset(); } int PagedSpace::MCSpaceOffsetForAddress(Address addr) { #ifdef DEBUG // The Contains function considers the address at the beginning of a // page in the page, MCSpaceOffsetForAddress considers it is in the // previous page. if (Page::IsAlignedToPageSize(addr)) { ASSERT(Contains(addr - kPointerSize)); } else { ASSERT(Contains(addr)); } #endif // If addr is at the end of a page, it belongs to previous page Page* p = Page::IsAlignedToPageSize(addr) ? Page::FromAllocationTop(addr) : Page::FromAddress(addr); int index = p->mc_page_index; return (index * Page::kPageSize) + p->Offset(addr); } // Slow case for reallocating and promoting objects during a compacting // collection. This function is not space-specific. HeapObject* PagedSpace::SlowMCAllocateRaw(int size_in_bytes) { Page* current_page = TopPageOf(mc_forwarding_info_); if (!current_page->next_page()->is_valid()) { if (!Expand(current_page)) { return NULL; } } // There are surely more pages in the space now. ASSERT(current_page->next_page()->is_valid()); // We do not add the top of page block for current page to the space's // free list---the block may contain live objects so we cannot write // bookkeeping information to it. Instead, we will recover top of page // blocks when we move objects to their new locations. // // We do however write the allocation pointer to the page. The encoding // of forwarding addresses is as an offset in terms of live bytes, so we // need quick access to the allocation top of each page to decode // forwarding addresses. current_page->SetAllocationWatermark(mc_forwarding_info_.top); current_page->next_page()->InvalidateWatermark(true); SetAllocationInfo(&mc_forwarding_info_, current_page->next_page()); return AllocateLinearly(&mc_forwarding_info_, size_in_bytes); } bool PagedSpace::Expand(Page* last_page) { ASSERT(max_capacity_ % Page::kObjectAreaSize == 0); ASSERT(Capacity() % Page::kObjectAreaSize == 0); if (Capacity() == max_capacity_) return false; ASSERT(Capacity() < max_capacity_); // Last page must be valid and its next page is invalid. ASSERT(last_page->is_valid() && !last_page->next_page()->is_valid()); int available_pages = static_cast((max_capacity_ - Capacity()) / Page::kObjectAreaSize); // We don't want to have to handle small chunks near the end so if there are // not kPagesPerChunk pages available without exceeding the max capacity then // act as if memory has run out. if (available_pages < MemoryAllocator::kPagesPerChunk) return false; int desired_pages = Min(available_pages, MemoryAllocator::kPagesPerChunk); Page* p = heap()->isolate()->memory_allocator()->AllocatePages( desired_pages, &desired_pages, this); if (!p->is_valid()) return false; accounting_stats_.ExpandSpace(desired_pages * Page::kObjectAreaSize); ASSERT(Capacity() <= max_capacity_); heap()->isolate()->memory_allocator()->SetNextPage(last_page, p); // Sequentially clear region marks of new pages and and cache the // new last page in the space. while (p->is_valid()) { p->SetRegionMarks(Page::kAllRegionsCleanMarks); last_page_ = p; p = p->next_page(); } return true; } #ifdef DEBUG int PagedSpace::CountTotalPages() { int count = 0; for (Page* p = first_page_; p->is_valid(); p = p->next_page()) { count++; } return count; } #endif void PagedSpace::Shrink() { if (!page_list_is_chunk_ordered_) { // We can't shrink space if pages is not chunk-ordered // (see comment for class MemoryAllocator for definition). return; } // Release half of free pages. Page* top_page = AllocationTopPage(); ASSERT(top_page->is_valid()); // Count the number of pages we would like to free. int pages_to_free = 0; for (Page* p = top_page->next_page(); p->is_valid(); p = p->next_page()) { pages_to_free++; } // Free pages after top_page. Page* p = heap()->isolate()->memory_allocator()-> FreePages(top_page->next_page()); heap()->isolate()->memory_allocator()->SetNextPage(top_page, p); // Find out how many pages we failed to free and update last_page_. // Please note pages can only be freed in whole chunks. last_page_ = top_page; for (Page* p = top_page->next_page(); p->is_valid(); p = p->next_page()) { pages_to_free--; last_page_ = p; } accounting_stats_.ShrinkSpace(pages_to_free * Page::kObjectAreaSize); ASSERT(Capacity() == CountTotalPages() * Page::kObjectAreaSize); } bool PagedSpace::EnsureCapacity(int capacity) { if (Capacity() >= capacity) return true; // Start from the allocation top and loop to the last page in the space. Page* last_page = AllocationTopPage(); Page* next_page = last_page->next_page(); while (next_page->is_valid()) { last_page = heap()->isolate()->memory_allocator()-> FindLastPageInSameChunk(next_page); next_page = last_page->next_page(); } // Expand the space until it has the required capacity or expansion fails. do { if (!Expand(last_page)) return false; ASSERT(last_page->next_page()->is_valid()); last_page = heap()->isolate()->memory_allocator()->FindLastPageInSameChunk( last_page->next_page()); } while (Capacity() < capacity); return true; } #ifdef DEBUG void PagedSpace::Print() { } #endif #ifdef DEBUG // We do not assume that the PageIterator works, because it depends on the // invariants we are checking during verification. void PagedSpace::Verify(ObjectVisitor* visitor) { // The allocation pointer should be valid, and it should be in a page in the // space. ASSERT(allocation_info_.VerifyPagedAllocation()); Page* top_page = Page::FromAllocationTop(allocation_info_.top); ASSERT(heap()->isolate()->memory_allocator()->IsPageInSpace(top_page, this)); // Loop over all the pages. bool above_allocation_top = false; Page* current_page = first_page_; while (current_page->is_valid()) { if (above_allocation_top) { // We don't care what's above the allocation top. } else { Address top = current_page->AllocationTop(); if (current_page == top_page) { ASSERT(top == allocation_info_.top); // The next page will be above the allocation top. above_allocation_top = true; } // It should be packed with objects from the bottom to the top. Address current = current_page->ObjectAreaStart(); while (current < top) { HeapObject* object = HeapObject::FromAddress(current); // The first word should be a map, and we expect all map pointers to // be in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(heap()->map_space()->Contains(map)); // Perform space-specific object verification. VerifyObject(object); // The object itself should look OK. object->Verify(); // All the interior pointers should be contained in the heap and // have page regions covering intergenerational references should be // marked dirty. int size = object->Size(); object->IterateBody(map->instance_type(), size, visitor); current += size; } // The allocation pointer should not be in the middle of an object. ASSERT(current == top); } current_page = current_page->next_page(); } } #endif // ----------------------------------------------------------------------------- // NewSpace implementation bool NewSpace::Setup(Address start, int size) { // Setup new space based on the preallocated memory block defined by // start and size. The provided space is divided into two semi-spaces. // To support fast containment testing in the new space, the size of // this chunk must be a power of two and it must be aligned to its size. int initial_semispace_capacity = heap()->InitialSemiSpaceSize(); int maximum_semispace_capacity = heap()->MaxSemiSpaceSize(); ASSERT(initial_semispace_capacity <= maximum_semispace_capacity); ASSERT(IsPowerOf2(maximum_semispace_capacity)); // Allocate and setup the histogram arrays if necessary. allocated_histogram_ = NewArray(LAST_TYPE + 1); promoted_histogram_ = NewArray(LAST_TYPE + 1); #define SET_NAME(name) allocated_histogram_[name].set_name(#name); \ promoted_histogram_[name].set_name(#name); INSTANCE_TYPE_LIST(SET_NAME) #undef SET_NAME ASSERT(size == 2 * heap()->ReservedSemiSpaceSize()); ASSERT(IsAddressAligned(start, size, 0)); if (!to_space_.Setup(start, initial_semispace_capacity, maximum_semispace_capacity)) { return false; } if (!from_space_.Setup(start + maximum_semispace_capacity, initial_semispace_capacity, maximum_semispace_capacity)) { return false; } start_ = start; address_mask_ = ~(size - 1); object_mask_ = address_mask_ | kHeapObjectTagMask; object_expected_ = reinterpret_cast(start) | kHeapObjectTag; allocation_info_.top = to_space_.low(); allocation_info_.limit = to_space_.high(); mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); return true; } void NewSpace::TearDown() { if (allocated_histogram_) { DeleteArray(allocated_histogram_); allocated_histogram_ = NULL; } if (promoted_histogram_) { DeleteArray(promoted_histogram_); promoted_histogram_ = NULL; } start_ = NULL; allocation_info_.top = NULL; allocation_info_.limit = NULL; mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; to_space_.TearDown(); from_space_.TearDown(); } void NewSpace::Flip() { SemiSpace tmp = from_space_; from_space_ = to_space_; to_space_ = tmp; } void NewSpace::Grow() { ASSERT(Capacity() < MaximumCapacity()); if (to_space_.Grow()) { // Only grow from space if we managed to grow to space. if (!from_space_.Grow()) { // If we managed to grow to space but couldn't grow from space, // attempt to shrink to space. if (!to_space_.ShrinkTo(from_space_.Capacity())) { // We are in an inconsistent state because we could not // commit/uncommit memory from new space. V8::FatalProcessOutOfMemory("Failed to grow new space."); } } } allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } void NewSpace::Shrink() { int new_capacity = Max(InitialCapacity(), 2 * SizeAsInt()); int rounded_new_capacity = RoundUp(new_capacity, static_cast(OS::AllocateAlignment())); if (rounded_new_capacity < Capacity() && to_space_.ShrinkTo(rounded_new_capacity)) { // Only shrink from space if we managed to shrink to space. if (!from_space_.ShrinkTo(rounded_new_capacity)) { // If we managed to shrink to space but couldn't shrink from // space, attempt to grow to space again. if (!to_space_.GrowTo(from_space_.Capacity())) { // We are in an inconsistent state because we could not // commit/uncommit memory from new space. V8::FatalProcessOutOfMemory("Failed to shrink new space."); } } } allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } void NewSpace::ResetAllocationInfo() { allocation_info_.top = to_space_.low(); allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } void NewSpace::MCResetRelocationInfo() { mc_forwarding_info_.top = from_space_.low(); mc_forwarding_info_.limit = from_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(mc_forwarding_info_, from_space_); } void NewSpace::MCCommitRelocationInfo() { // Assumes that the spaces have been flipped so that mc_forwarding_info_ is // valid allocation info for the to space. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } #ifdef DEBUG // We do not use the SemispaceIterator because verification doesn't assume // that it works (it depends on the invariants we are checking). void NewSpace::Verify() { // The allocation pointer should be in the space or at the very end. ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); // There should be objects packed in from the low address up to the // allocation pointer. Address current = to_space_.low(); while (current < top()) { HeapObject* object = HeapObject::FromAddress(current); // The first word should be a map, and we expect all map pointers to // be in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(heap()->map_space()->Contains(map)); // The object should not be code or a map. ASSERT(!object->IsMap()); ASSERT(!object->IsCode()); // The object itself should look OK. object->Verify(); // All the interior pointers should be contained in the heap. VerifyPointersVisitor visitor; int size = object->Size(); object->IterateBody(map->instance_type(), size, &visitor); current += size; } // The allocation pointer should not be in the middle of an object. ASSERT(current == top()); } #endif bool SemiSpace::Commit() { ASSERT(!is_committed()); if (!heap()->isolate()->memory_allocator()->CommitBlock( start_, capacity_, executable())) { return false; } committed_ = true; return true; } bool SemiSpace::Uncommit() { ASSERT(is_committed()); if (!heap()->isolate()->memory_allocator()->UncommitBlock( start_, capacity_)) { return false; } committed_ = false; return true; } // ----------------------------------------------------------------------------- // SemiSpace implementation bool SemiSpace::Setup(Address start, int initial_capacity, int maximum_capacity) { // Creates a space in the young generation. The constructor does not // allocate memory from the OS. A SemiSpace is given a contiguous chunk of // memory of size 'capacity' when set up, and does not grow or shrink // otherwise. In the mark-compact collector, the memory region of the from // space is used as the marking stack. It requires contiguous memory // addresses. initial_capacity_ = initial_capacity; capacity_ = initial_capacity; maximum_capacity_ = maximum_capacity; committed_ = false; start_ = start; address_mask_ = ~(maximum_capacity - 1); object_mask_ = address_mask_ | kHeapObjectTagMask; object_expected_ = reinterpret_cast(start) | kHeapObjectTag; age_mark_ = start_; return Commit(); } void SemiSpace::TearDown() { start_ = NULL; capacity_ = 0; } bool SemiSpace::Grow() { // Double the semispace size but only up to maximum capacity. int maximum_extra = maximum_capacity_ - capacity_; int extra = Min(RoundUp(capacity_, static_cast(OS::AllocateAlignment())), maximum_extra); if (!heap()->isolate()->memory_allocator()->CommitBlock( high(), extra, executable())) { return false; } capacity_ += extra; return true; } bool SemiSpace::GrowTo(int new_capacity) { ASSERT(new_capacity <= maximum_capacity_); ASSERT(new_capacity > capacity_); size_t delta = new_capacity - capacity_; ASSERT(IsAligned(delta, OS::AllocateAlignment())); if (!heap()->isolate()->memory_allocator()->CommitBlock( high(), delta, executable())) { return false; } capacity_ = new_capacity; return true; } bool SemiSpace::ShrinkTo(int new_capacity) { ASSERT(new_capacity >= initial_capacity_); ASSERT(new_capacity < capacity_); size_t delta = capacity_ - new_capacity; ASSERT(IsAligned(delta, OS::AllocateAlignment())); if (!heap()->isolate()->memory_allocator()->UncommitBlock( high() - delta, delta)) { return false; } capacity_ = new_capacity; return true; } #ifdef DEBUG void SemiSpace::Print() { } void SemiSpace::Verify() { } #endif // ----------------------------------------------------------------------------- // SemiSpaceIterator implementation. SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) { Initialize(space, space->bottom(), space->top(), NULL); } SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, HeapObjectCallback size_func) { Initialize(space, space->bottom(), space->top(), size_func); } SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, Address start) { Initialize(space, start, space->top(), NULL); } void SemiSpaceIterator::Initialize(NewSpace* space, Address start, Address end, HeapObjectCallback size_func) { ASSERT(space->ToSpaceContains(start)); ASSERT(space->ToSpaceLow() <= end && end <= space->ToSpaceHigh()); space_ = &space->to_space_; current_ = start; limit_ = end; size_func_ = size_func; } #ifdef DEBUG // heap_histograms is shared, always clear it before using it. static void ClearHistograms() { Isolate* isolate = Isolate::Current(); // We reset the name each time, though it hasn't changed. #define DEF_TYPE_NAME(name) isolate->heap_histograms()[name].set_name(#name); INSTANCE_TYPE_LIST(DEF_TYPE_NAME) #undef DEF_TYPE_NAME #define CLEAR_HISTOGRAM(name) isolate->heap_histograms()[name].clear(); INSTANCE_TYPE_LIST(CLEAR_HISTOGRAM) #undef CLEAR_HISTOGRAM isolate->js_spill_information()->Clear(); } static void ClearCodeKindStatistics() { Isolate* isolate = Isolate::Current(); for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { isolate->code_kind_statistics()[i] = 0; } } static void ReportCodeKindStatistics() { Isolate* isolate = Isolate::Current(); const char* table[Code::NUMBER_OF_KINDS] = { NULL }; #define CASE(name) \ case Code::name: table[Code::name] = #name; \ break for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { switch (static_cast(i)) { CASE(FUNCTION); CASE(OPTIMIZED_FUNCTION); CASE(STUB); CASE(BUILTIN); CASE(LOAD_IC); CASE(KEYED_LOAD_IC); CASE(STORE_IC); CASE(KEYED_STORE_IC); CASE(CALL_IC); CASE(KEYED_CALL_IC); CASE(UNARY_OP_IC); CASE(BINARY_OP_IC); CASE(COMPARE_IC); CASE(TO_BOOLEAN_IC); } } #undef CASE PrintF("\n Code kind histograms: \n"); for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { if (isolate->code_kind_statistics()[i] > 0) { PrintF(" %-20s: %10d bytes\n", table[i], isolate->code_kind_statistics()[i]); } } PrintF("\n"); } static int CollectHistogramInfo(HeapObject* obj) { Isolate* isolate = Isolate::Current(); InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); ASSERT(isolate->heap_histograms()[type].name() != NULL); isolate->heap_histograms()[type].increment_number(1); isolate->heap_histograms()[type].increment_bytes(obj->Size()); if (FLAG_collect_heap_spill_statistics && obj->IsJSObject()) { JSObject::cast(obj)->IncrementSpillStatistics( isolate->js_spill_information()); } return obj->Size(); } static void ReportHistogram(bool print_spill) { Isolate* isolate = Isolate::Current(); PrintF("\n Object Histogram:\n"); for (int i = 0; i <= LAST_TYPE; i++) { if (isolate->heap_histograms()[i].number() > 0) { PrintF(" %-34s%10d (%10d bytes)\n", isolate->heap_histograms()[i].name(), isolate->heap_histograms()[i].number(), isolate->heap_histograms()[i].bytes()); } } PrintF("\n"); // Summarize string types. int string_number = 0; int string_bytes = 0; #define INCREMENT(type, size, name, camel_name) \ string_number += isolate->heap_histograms()[type].number(); \ string_bytes += isolate->heap_histograms()[type].bytes(); STRING_TYPE_LIST(INCREMENT) #undef INCREMENT if (string_number > 0) { PrintF(" %-34s%10d (%10d bytes)\n\n", "STRING_TYPE", string_number, string_bytes); } if (FLAG_collect_heap_spill_statistics && print_spill) { isolate->js_spill_information()->Print(); } } #endif // DEBUG // Support for statistics gathering for --heap-stats and --log-gc. void NewSpace::ClearHistograms() { for (int i = 0; i <= LAST_TYPE; i++) { allocated_histogram_[i].clear(); promoted_histogram_[i].clear(); } } // Because the copying collector does not touch garbage objects, we iterate // the new space before a collection to get a histogram of allocated objects. // This only happens when --log-gc flag is set. void NewSpace::CollectStatistics() { ClearHistograms(); SemiSpaceIterator it(this); for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) RecordAllocation(obj); } static void DoReportStatistics(Isolate* isolate, HistogramInfo* info, const char* description) { LOG(isolate, HeapSampleBeginEvent("NewSpace", description)); // Lump all the string types together. int string_number = 0; int string_bytes = 0; #define INCREMENT(type, size, name, camel_name) \ string_number += info[type].number(); \ string_bytes += info[type].bytes(); STRING_TYPE_LIST(INCREMENT) #undef INCREMENT if (string_number > 0) { LOG(isolate, HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes)); } // Then do the other types. for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) { if (info[i].number() > 0) { LOG(isolate, HeapSampleItemEvent(info[i].name(), info[i].number(), info[i].bytes())); } } LOG(isolate, HeapSampleEndEvent("NewSpace", description)); } void NewSpace::ReportStatistics() { #ifdef DEBUG if (FLAG_heap_stats) { float pct = static_cast(Available()) / Capacity(); PrintF(" capacity: %" V8_PTR_PREFIX "d" ", available: %" V8_PTR_PREFIX "d, %%%d\n", Capacity(), Available(), static_cast(pct*100)); PrintF("\n Object Histogram:\n"); for (int i = 0; i <= LAST_TYPE; i++) { if (allocated_histogram_[i].number() > 0) { PrintF(" %-34s%10d (%10d bytes)\n", allocated_histogram_[i].name(), allocated_histogram_[i].number(), allocated_histogram_[i].bytes()); } } PrintF("\n"); } #endif // DEBUG if (FLAG_log_gc) { Isolate* isolate = ISOLATE; DoReportStatistics(isolate, allocated_histogram_, "allocated"); DoReportStatistics(isolate, promoted_histogram_, "promoted"); } } void NewSpace::RecordAllocation(HeapObject* obj) { InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); allocated_histogram_[type].increment_number(1); allocated_histogram_[type].increment_bytes(obj->Size()); } void NewSpace::RecordPromotion(HeapObject* obj) { InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); promoted_histogram_[type].increment_number(1); promoted_histogram_[type].increment_bytes(obj->Size()); } // ----------------------------------------------------------------------------- // Free lists for old object spaces implementation void FreeListNode::set_size(Heap* heap, int size_in_bytes) { ASSERT(size_in_bytes > 0); ASSERT(IsAligned(size_in_bytes, kPointerSize)); // We write a map and possibly size information to the block. If the block // is big enough to be a ByteArray with at least one extra word (the next // pointer), we set its map to be the byte array map and its size to an // appropriate array length for the desired size from HeapObject::Size(). // If the block is too small (eg, one or two words), to hold both a size // field and a next pointer, we give it a filler map that gives it the // correct size. if (size_in_bytes > ByteArray::kHeaderSize) { set_map(heap->raw_unchecked_byte_array_map()); // Can't use ByteArray::cast because it fails during deserialization. ByteArray* this_as_byte_array = reinterpret_cast(this); this_as_byte_array->set_length(ByteArray::LengthFor(size_in_bytes)); } else if (size_in_bytes == kPointerSize) { set_map(heap->raw_unchecked_one_pointer_filler_map()); } else if (size_in_bytes == 2 * kPointerSize) { set_map(heap->raw_unchecked_two_pointer_filler_map()); } else { UNREACHABLE(); } // We would like to ASSERT(Size() == size_in_bytes) but this would fail during // deserialization because the byte array map is not done yet. } Address FreeListNode::next(Heap* heap) { ASSERT(IsFreeListNode(this)); if (map() == heap->raw_unchecked_byte_array_map()) { ASSERT(Size() >= kNextOffset + kPointerSize); return Memory::Address_at(address() + kNextOffset); } else { return Memory::Address_at(address() + kPointerSize); } } void FreeListNode::set_next(Heap* heap, Address next) { ASSERT(IsFreeListNode(this)); if (map() == heap->raw_unchecked_byte_array_map()) { ASSERT(Size() >= kNextOffset + kPointerSize); Memory::Address_at(address() + kNextOffset) = next; } else { Memory::Address_at(address() + kPointerSize) = next; } } OldSpaceFreeList::OldSpaceFreeList(Heap* heap, AllocationSpace owner) : heap_(heap), owner_(owner) { Reset(); } void OldSpaceFreeList::Reset() { available_ = 0; for (int i = 0; i < kFreeListsLength; i++) { free_[i].head_node_ = NULL; } needs_rebuild_ = false; finger_ = kHead; free_[kHead].next_size_ = kEnd; } void OldSpaceFreeList::RebuildSizeList() { ASSERT(needs_rebuild_); int cur = kHead; for (int i = cur + 1; i < kFreeListsLength; i++) { if (free_[i].head_node_ != NULL) { free_[cur].next_size_ = i; cur = i; } } free_[cur].next_size_ = kEnd; needs_rebuild_ = false; } int OldSpaceFreeList::Free(Address start, int size_in_bytes) { #ifdef DEBUG Isolate::Current()->memory_allocator()->ZapBlock(start, size_in_bytes); #endif FreeListNode* node = FreeListNode::FromAddress(start); node->set_size(heap_, size_in_bytes); // We don't use the freelists in compacting mode. This makes it more like a // GC that only has mark-sweep-compact and doesn't have a mark-sweep // collector. if (FLAG_always_compact) { return size_in_bytes; } // Early return to drop too-small blocks on the floor (one or two word // blocks cannot hold a map pointer, a size field, and a pointer to the // next block in the free list). if (size_in_bytes < kMinBlockSize) { return size_in_bytes; } // Insert other blocks at the head of an exact free list. int index = size_in_bytes >> kPointerSizeLog2; node->set_next(heap_, free_[index].head_node_); free_[index].head_node_ = node->address(); available_ += size_in_bytes; needs_rebuild_ = true; return 0; } MaybeObject* OldSpaceFreeList::Allocate(int size_in_bytes, int* wasted_bytes) { ASSERT(0 < size_in_bytes); ASSERT(size_in_bytes <= kMaxBlockSize); ASSERT(IsAligned(size_in_bytes, kPointerSize)); if (needs_rebuild_) RebuildSizeList(); int index = size_in_bytes >> kPointerSizeLog2; // Check for a perfect fit. if (free_[index].head_node_ != NULL) { FreeListNode* node = FreeListNode::FromAddress(free_[index].head_node_); // If this was the last block of its size, remove the size. if ((free_[index].head_node_ = node->next(heap_)) == NULL) RemoveSize(index); available_ -= size_in_bytes; *wasted_bytes = 0; ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. return node; } // Search the size list for the best fit. int prev = finger_ < index ? finger_ : kHead; int cur = FindSize(index, &prev); ASSERT(index < cur); if (cur == kEnd) { // No large enough size in list. *wasted_bytes = 0; return Failure::RetryAfterGC(owner_); } ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. int rem = cur - index; int rem_bytes = rem << kPointerSizeLog2; FreeListNode* cur_node = FreeListNode::FromAddress(free_[cur].head_node_); ASSERT(cur_node->Size() == (cur << kPointerSizeLog2)); FreeListNode* rem_node = FreeListNode::FromAddress(free_[cur].head_node_ + size_in_bytes); // Distinguish the cases prev < rem < cur and rem <= prev < cur // to avoid many redundant tests and calls to Insert/RemoveSize. if (prev < rem) { // Simple case: insert rem between prev and cur. finger_ = prev; free_[prev].next_size_ = rem; // If this was the last block of size cur, remove the size. if ((free_[cur].head_node_ = cur_node->next(heap_)) == NULL) { free_[rem].next_size_ = free_[cur].next_size_; } else { free_[rem].next_size_ = cur; } // Add the remainder block. rem_node->set_size(heap_, rem_bytes); rem_node->set_next(heap_, free_[rem].head_node_); free_[rem].head_node_ = rem_node->address(); } else { // If this was the last block of size cur, remove the size. if ((free_[cur].head_node_ = cur_node->next(heap_)) == NULL) { finger_ = prev; free_[prev].next_size_ = free_[cur].next_size_; } if (rem_bytes < kMinBlockSize) { // Too-small remainder is wasted. rem_node->set_size(heap_, rem_bytes); available_ -= size_in_bytes + rem_bytes; *wasted_bytes = rem_bytes; return cur_node; } // Add the remainder block and, if needed, insert its size. rem_node->set_size(heap_, rem_bytes); rem_node->set_next(heap_, free_[rem].head_node_); free_[rem].head_node_ = rem_node->address(); if (rem_node->next(heap_) == NULL) InsertSize(rem); } available_ -= size_in_bytes; *wasted_bytes = 0; return cur_node; } void OldSpaceFreeList::MarkNodes() { for (int i = 0; i < kFreeListsLength; i++) { Address cur_addr = free_[i].head_node_; while (cur_addr != NULL) { FreeListNode* cur_node = FreeListNode::FromAddress(cur_addr); cur_addr = cur_node->next(heap_); cur_node->SetMark(); } } } #ifdef DEBUG bool OldSpaceFreeList::Contains(FreeListNode* node) { for (int i = 0; i < kFreeListsLength; i++) { Address cur_addr = free_[i].head_node_; while (cur_addr != NULL) { FreeListNode* cur_node = FreeListNode::FromAddress(cur_addr); if (cur_node == node) return true; cur_addr = cur_node->next(heap_); } } return false; } #endif FixedSizeFreeList::FixedSizeFreeList(Heap* heap, AllocationSpace owner, int object_size) : heap_(heap), owner_(owner), object_size_(object_size) { Reset(); } void FixedSizeFreeList::Reset() { available_ = 0; head_ = tail_ = NULL; } void FixedSizeFreeList::Free(Address start) { #ifdef DEBUG Isolate::Current()->memory_allocator()->ZapBlock(start, object_size_); #endif // We only use the freelists with mark-sweep. ASSERT(!HEAP->mark_compact_collector()->IsCompacting()); FreeListNode* node = FreeListNode::FromAddress(start); node->set_size(heap_, object_size_); node->set_next(heap_, NULL); if (head_ == NULL) { tail_ = head_ = node->address(); } else { FreeListNode::FromAddress(tail_)->set_next(heap_, node->address()); tail_ = node->address(); } available_ += object_size_; } MaybeObject* FixedSizeFreeList::Allocate() { if (head_ == NULL) { return Failure::RetryAfterGC(owner_); } ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. FreeListNode* node = FreeListNode::FromAddress(head_); head_ = node->next(heap_); available_ -= object_size_; return node; } void FixedSizeFreeList::MarkNodes() { Address cur_addr = head_; while (cur_addr != NULL && cur_addr != tail_) { FreeListNode* cur_node = FreeListNode::FromAddress(cur_addr); cur_addr = cur_node->next(heap_); cur_node->SetMark(); } } // ----------------------------------------------------------------------------- // OldSpace implementation void OldSpace::PrepareForMarkCompact(bool will_compact) { // Call prepare of the super class. PagedSpace::PrepareForMarkCompact(will_compact); if (will_compact) { // Reset relocation info. During a compacting collection, everything in // the space is considered 'available' and we will rediscover live data // and waste during the collection. MCResetRelocationInfo(); ASSERT(Available() == Capacity()); } else { // During a non-compacting collection, everything below the linear // allocation pointer is considered allocated (everything above is // available) and we will rediscover available and wasted bytes during // the collection. accounting_stats_.AllocateBytes(free_list_.available()); accounting_stats_.FillWastedBytes(Waste()); } // Clear the free list before a full GC---it will be rebuilt afterward. free_list_.Reset(); } void OldSpace::MCCommitRelocationInfo() { // Update fast allocation info. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = mc_forwarding_info_.limit; ASSERT(allocation_info_.VerifyPagedAllocation()); // The space is compacted and we haven't yet built free lists or // wasted any space. ASSERT(Waste() == 0); ASSERT(AvailableFree() == 0); // Build the free list for the space. int computed_size = 0; PageIterator it(this, PageIterator::PAGES_USED_BY_MC); while (it.has_next()) { Page* p = it.next(); // Space below the relocation pointer is allocated. computed_size += static_cast(p->AllocationWatermark() - p->ObjectAreaStart()); if (it.has_next()) { // Free the space at the top of the page. int extra_size = static_cast(p->ObjectAreaEnd() - p->AllocationWatermark()); if (extra_size > 0) { int wasted_bytes = free_list_.Free(p->AllocationWatermark(), extra_size); // The bytes we have just "freed" to add to the free list were // already accounted as available. accounting_stats_.WasteBytes(wasted_bytes); } } } // Make sure the computed size - based on the used portion of the pages in // use - matches the size obtained while computing forwarding addresses. ASSERT(computed_size == Size()); } bool NewSpace::ReserveSpace(int bytes) { // We can't reliably unpack a partial snapshot that needs more new space // space than the minimum NewSpace size. ASSERT(bytes <= InitialCapacity()); Address limit = allocation_info_.limit; Address top = allocation_info_.top; return limit - top >= bytes; } void PagedSpace::FreePages(Page* prev, Page* last) { if (last == AllocationTopPage()) { // Pages are already at the end of used pages. return; } Page* first = NULL; // Remove pages from the list. if (prev == NULL) { first = first_page_; first_page_ = last->next_page(); } else { first = prev->next_page(); heap()->isolate()->memory_allocator()->SetNextPage( prev, last->next_page()); } // Attach it after the last page. heap()->isolate()->memory_allocator()->SetNextPage(last_page_, first); last_page_ = last; heap()->isolate()->memory_allocator()->SetNextPage(last, NULL); // Clean them up. do { first->InvalidateWatermark(true); first->SetAllocationWatermark(first->ObjectAreaStart()); first->SetCachedAllocationWatermark(first->ObjectAreaStart()); first->SetRegionMarks(Page::kAllRegionsCleanMarks); first = first->next_page(); } while (first != NULL); // Order of pages in this space might no longer be consistent with // order of pages in chunks. page_list_is_chunk_ordered_ = false; } void PagedSpace::RelinkPageListInChunkOrder(bool deallocate_blocks) { const bool add_to_freelist = true; // Mark used and unused pages to properly fill unused pages // after reordering. PageIterator all_pages_iterator(this, PageIterator::ALL_PAGES); Page* last_in_use = AllocationTopPage(); bool in_use = true; while (all_pages_iterator.has_next()) { Page* p = all_pages_iterator.next(); p->SetWasInUseBeforeMC(in_use); if (p == last_in_use) { // We passed a page containing allocation top. All consequent // pages are not used. in_use = false; } } if (page_list_is_chunk_ordered_) return; Page* new_last_in_use = Page::FromAddress(NULL); heap()->isolate()->memory_allocator()->RelinkPageListInChunkOrder( this, &first_page_, &last_page_, &new_last_in_use); ASSERT(new_last_in_use->is_valid()); if (new_last_in_use != last_in_use) { // Current allocation top points to a page which is now in the middle // of page list. We should move allocation top forward to the new last // used page so various object iterators will continue to work properly. int size_in_bytes = static_cast(PageAllocationLimit(last_in_use) - last_in_use->AllocationTop()); last_in_use->SetAllocationWatermark(last_in_use->AllocationTop()); if (size_in_bytes > 0) { Address start = last_in_use->AllocationTop(); if (deallocate_blocks) { accounting_stats_.AllocateBytes(size_in_bytes); DeallocateBlock(start, size_in_bytes, add_to_freelist); } else { heap()->CreateFillerObjectAt(start, size_in_bytes); } } // New last in use page was in the middle of the list before // sorting so it full. SetTop(new_last_in_use->AllocationTop()); ASSERT(AllocationTopPage() == new_last_in_use); ASSERT(AllocationTopPage()->WasInUseBeforeMC()); } PageIterator pages_in_use_iterator(this, PageIterator::PAGES_IN_USE); while (pages_in_use_iterator.has_next()) { Page* p = pages_in_use_iterator.next(); if (!p->WasInUseBeforeMC()) { // Empty page is in the middle of a sequence of used pages. // Allocate it as a whole and deallocate immediately. int size_in_bytes = static_cast(PageAllocationLimit(p) - p->ObjectAreaStart()); p->SetAllocationWatermark(p->ObjectAreaStart()); Address start = p->ObjectAreaStart(); if (deallocate_blocks) { accounting_stats_.AllocateBytes(size_in_bytes); DeallocateBlock(start, size_in_bytes, add_to_freelist); } else { heap()->CreateFillerObjectAt(start, size_in_bytes); } } } page_list_is_chunk_ordered_ = true; } void PagedSpace::PrepareForMarkCompact(bool will_compact) { if (will_compact) { RelinkPageListInChunkOrder(false); } } bool PagedSpace::ReserveSpace(int bytes) { Address limit = allocation_info_.limit; Address top = allocation_info_.top; if (limit - top >= bytes) return true; // There wasn't enough space in the current page. Lets put the rest // of the page on the free list and start a fresh page. PutRestOfCurrentPageOnFreeList(TopPageOf(allocation_info_)); Page* reserved_page = TopPageOf(allocation_info_); int bytes_left_to_reserve = bytes; while (bytes_left_to_reserve > 0) { if (!reserved_page->next_page()->is_valid()) { if (heap()->OldGenerationAllocationLimitReached()) return false; Expand(reserved_page); } bytes_left_to_reserve -= Page::kPageSize; reserved_page = reserved_page->next_page(); if (!reserved_page->is_valid()) return false; } ASSERT(TopPageOf(allocation_info_)->next_page()->is_valid()); TopPageOf(allocation_info_)->next_page()->InvalidateWatermark(true); SetAllocationInfo(&allocation_info_, TopPageOf(allocation_info_)->next_page()); return true; } // You have to call this last, since the implementation from PagedSpace // doesn't know that memory was 'promised' to large object space. bool LargeObjectSpace::ReserveSpace(int bytes) { return heap()->OldGenerationSpaceAvailable() >= bytes; } // Slow case for normal allocation. Try in order: (1) allocate in the next // page in the space, (2) allocate off the space's free list, (3) expand the // space, (4) fail. HeapObject* OldSpace::SlowAllocateRaw(int size_in_bytes) { // Linear allocation in this space has failed. If there is another page // in the space, move to that page and allocate there. This allocation // should succeed (size_in_bytes should not be greater than a page's // object area size). Page* current_page = TopPageOf(allocation_info_); if (current_page->next_page()->is_valid()) { return AllocateInNextPage(current_page, size_in_bytes); } // There is no next page in this space. Try free list allocation unless that // is currently forbidden. if (!heap()->linear_allocation()) { int wasted_bytes; Object* result; MaybeObject* maybe = free_list_.Allocate(size_in_bytes, &wasted_bytes); accounting_stats_.WasteBytes(wasted_bytes); if (maybe->ToObject(&result)) { accounting_stats_.AllocateBytes(size_in_bytes); HeapObject* obj = HeapObject::cast(result); Page* p = Page::FromAddress(obj->address()); if (obj->address() >= p->AllocationWatermark()) { // There should be no hole between the allocation watermark // and allocated object address. // Memory above the allocation watermark was not swept and // might contain garbage pointers to new space. ASSERT(obj->address() == p->AllocationWatermark()); p->SetAllocationWatermark(obj->address() + size_in_bytes); } return obj; } } // Free list allocation failed and there is no next page. Fail if we have // hit the old generation size limit that should cause a garbage // collection. if (!heap()->always_allocate() && heap()->OldGenerationAllocationLimitReached()) { return NULL; } // Try to expand the space and allocate in the new next page. ASSERT(!current_page->next_page()->is_valid()); if (Expand(current_page)) { return AllocateInNextPage(current_page, size_in_bytes); } // Finally, fail. return NULL; } void OldSpace::PutRestOfCurrentPageOnFreeList(Page* current_page) { current_page->SetAllocationWatermark(allocation_info_.top); int free_size = static_cast(current_page->ObjectAreaEnd() - allocation_info_.top); if (free_size > 0) { int wasted_bytes = free_list_.Free(allocation_info_.top, free_size); accounting_stats_.WasteBytes(wasted_bytes); } } void FixedSpace::PutRestOfCurrentPageOnFreeList(Page* current_page) { current_page->SetAllocationWatermark(allocation_info_.top); int free_size = static_cast(current_page->ObjectAreaEnd() - allocation_info_.top); // In the fixed space free list all the free list items have the right size. // We use up the rest of the page while preserving this invariant. while (free_size >= object_size_in_bytes_) { free_list_.Free(allocation_info_.top); allocation_info_.top += object_size_in_bytes_; free_size -= object_size_in_bytes_; accounting_stats_.WasteBytes(object_size_in_bytes_); } } // Add the block at the top of the page to the space's free list, set the // allocation info to the next page (assumed to be one), and allocate // linearly there. HeapObject* OldSpace::AllocateInNextPage(Page* current_page, int size_in_bytes) { ASSERT(current_page->next_page()->is_valid()); Page* next_page = current_page->next_page(); next_page->ClearGCFields(); PutRestOfCurrentPageOnFreeList(current_page); SetAllocationInfo(&allocation_info_, next_page); return AllocateLinearly(&allocation_info_, size_in_bytes); } void OldSpace::DeallocateBlock(Address start, int size_in_bytes, bool add_to_freelist) { Free(start, size_in_bytes, add_to_freelist); } #ifdef DEBUG void PagedSpace::ReportCodeStatistics() { Isolate* isolate = Isolate::Current(); CommentStatistic* comments_statistics = isolate->paged_space_comments_statistics(); ReportCodeKindStatistics(); PrintF("Code comment statistics (\" [ comment-txt : size/ " "count (average)\"):\n"); for (int i = 0; i <= CommentStatistic::kMaxComments; i++) { const CommentStatistic& cs = comments_statistics[i]; if (cs.size > 0) { PrintF(" %-30s: %10d/%6d (%d)\n", cs.comment, cs.size, cs.count, cs.size/cs.count); } } PrintF("\n"); } void PagedSpace::ResetCodeStatistics() { Isolate* isolate = Isolate::Current(); CommentStatistic* comments_statistics = isolate->paged_space_comments_statistics(); ClearCodeKindStatistics(); for (int i = 0; i < CommentStatistic::kMaxComments; i++) { comments_statistics[i].Clear(); } comments_statistics[CommentStatistic::kMaxComments].comment = "Unknown"; comments_statistics[CommentStatistic::kMaxComments].size = 0; comments_statistics[CommentStatistic::kMaxComments].count = 0; } // Adds comment to 'comment_statistics' table. Performance OK as long as // 'kMaxComments' is small static void EnterComment(Isolate* isolate, const char* comment, int delta) { CommentStatistic* comments_statistics = isolate->paged_space_comments_statistics(); // Do not count empty comments if (delta <= 0) return; CommentStatistic* cs = &comments_statistics[CommentStatistic::kMaxComments]; // Search for a free or matching entry in 'comments_statistics': 'cs' // points to result. for (int i = 0; i < CommentStatistic::kMaxComments; i++) { if (comments_statistics[i].comment == NULL) { cs = &comments_statistics[i]; cs->comment = comment; break; } else if (strcmp(comments_statistics[i].comment, comment) == 0) { cs = &comments_statistics[i]; break; } } // Update entry for 'comment' cs->size += delta; cs->count += 1; } // Call for each nested comment start (start marked with '[ xxx', end marked // with ']'. RelocIterator 'it' must point to a comment reloc info. static void CollectCommentStatistics(Isolate* isolate, RelocIterator* it) { ASSERT(!it->done()); ASSERT(it->rinfo()->rmode() == RelocInfo::COMMENT); const char* tmp = reinterpret_cast(it->rinfo()->data()); if (tmp[0] != '[') { // Not a nested comment; skip return; } // Search for end of nested comment or a new nested comment const char* const comment_txt = reinterpret_cast(it->rinfo()->data()); const byte* prev_pc = it->rinfo()->pc(); int flat_delta = 0; it->next(); while (true) { // All nested comments must be terminated properly, and therefore exit // from loop. ASSERT(!it->done()); if (it->rinfo()->rmode() == RelocInfo::COMMENT) { const char* const txt = reinterpret_cast(it->rinfo()->data()); flat_delta += static_cast(it->rinfo()->pc() - prev_pc); if (txt[0] == ']') break; // End of nested comment // A new comment CollectCommentStatistics(isolate, it); // Skip code that was covered with previous comment prev_pc = it->rinfo()->pc(); } it->next(); } EnterComment(isolate, comment_txt, flat_delta); } // Collects code size statistics: // - by code kind // - by code comment void PagedSpace::CollectCodeStatistics() { Isolate* isolate = heap()->isolate(); HeapObjectIterator obj_it(this); for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) { if (obj->IsCode()) { Code* code = Code::cast(obj); isolate->code_kind_statistics()[code->kind()] += code->Size(); RelocIterator it(code); int delta = 0; const byte* prev_pc = code->instruction_start(); while (!it.done()) { if (it.rinfo()->rmode() == RelocInfo::COMMENT) { delta += static_cast(it.rinfo()->pc() - prev_pc); CollectCommentStatistics(isolate, &it); prev_pc = it.rinfo()->pc(); } it.next(); } ASSERT(code->instruction_start() <= prev_pc && prev_pc <= code->instruction_end()); delta += static_cast(code->instruction_end() - prev_pc); EnterComment(isolate, "NoComment", delta); } } } void OldSpace::ReportStatistics() { int pct = static_cast(Available() * 100 / Capacity()); PrintF(" capacity: %" V8_PTR_PREFIX "d" ", waste: %" V8_PTR_PREFIX "d" ", available: %" V8_PTR_PREFIX "d, %%%d\n", Capacity(), Waste(), Available(), pct); ClearHistograms(); HeapObjectIterator obj_it(this); for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) CollectHistogramInfo(obj); ReportHistogram(true); } #endif // ----------------------------------------------------------------------------- // FixedSpace implementation void FixedSpace::PrepareForMarkCompact(bool will_compact) { // Call prepare of the super class. PagedSpace::PrepareForMarkCompact(will_compact); if (will_compact) { // Reset relocation info. MCResetRelocationInfo(); // During a compacting collection, everything in the space is considered // 'available' (set by the call to MCResetRelocationInfo) and we will // rediscover live and wasted bytes during the collection. ASSERT(Available() == Capacity()); } else { // During a non-compacting collection, everything below the linear // allocation pointer except wasted top-of-page blocks is considered // allocated and we will rediscover available bytes during the // collection. accounting_stats_.AllocateBytes(free_list_.available()); } // Clear the free list before a full GC---it will be rebuilt afterward. free_list_.Reset(); } void FixedSpace::MCCommitRelocationInfo() { // Update fast allocation info. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = mc_forwarding_info_.limit; ASSERT(allocation_info_.VerifyPagedAllocation()); // The space is compacted and we haven't yet wasted any space. ASSERT(Waste() == 0); // Update allocation_top of each page in use and compute waste. int computed_size = 0; PageIterator it(this, PageIterator::PAGES_USED_BY_MC); while (it.has_next()) { Page* page = it.next(); Address page_top = page->AllocationTop(); computed_size += static_cast(page_top - page->ObjectAreaStart()); if (it.has_next()) { accounting_stats_.WasteBytes( static_cast(page->ObjectAreaEnd() - page_top)); page->SetAllocationWatermark(page_top); } } // Make sure the computed size - based on the used portion of the // pages in use - matches the size we adjust during allocation. ASSERT(computed_size == Size()); } // Slow case for normal allocation. Try in order: (1) allocate in the next // page in the space, (2) allocate off the space's free list, (3) expand the // space, (4) fail. HeapObject* FixedSpace::SlowAllocateRaw(int size_in_bytes) { ASSERT_EQ(object_size_in_bytes_, size_in_bytes); // Linear allocation in this space has failed. If there is another page // in the space, move to that page and allocate there. This allocation // should succeed. Page* current_page = TopPageOf(allocation_info_); if (current_page->next_page()->is_valid()) { return AllocateInNextPage(current_page, size_in_bytes); } // There is no next page in this space. Try free list allocation unless // that is currently forbidden. The fixed space free list implicitly assumes // that all free blocks are of the fixed size. if (!heap()->linear_allocation()) { Object* result; MaybeObject* maybe = free_list_.Allocate(); if (maybe->ToObject(&result)) { accounting_stats_.AllocateBytes(size_in_bytes); HeapObject* obj = HeapObject::cast(result); Page* p = Page::FromAddress(obj->address()); if (obj->address() >= p->AllocationWatermark()) { // There should be no hole between the allocation watermark // and allocated object address. // Memory above the allocation watermark was not swept and // might contain garbage pointers to new space. ASSERT(obj->address() == p->AllocationWatermark()); p->SetAllocationWatermark(obj->address() + size_in_bytes); } return obj; } } // Free list allocation failed and there is no next page. Fail if we have // hit the old generation size limit that should cause a garbage // collection. if (!heap()->always_allocate() && heap()->OldGenerationAllocationLimitReached()) { return NULL; } // Try to expand the space and allocate in the new next page. ASSERT(!current_page->next_page()->is_valid()); if (Expand(current_page)) { return AllocateInNextPage(current_page, size_in_bytes); } // Finally, fail. return NULL; } // Move to the next page (there is assumed to be one) and allocate there. // The top of page block is always wasted, because it is too small to hold a // map. HeapObject* FixedSpace::AllocateInNextPage(Page* current_page, int size_in_bytes) { ASSERT(current_page->next_page()->is_valid()); ASSERT(allocation_info_.top == PageAllocationLimit(current_page)); ASSERT_EQ(object_size_in_bytes_, size_in_bytes); Page* next_page = current_page->next_page(); next_page->ClearGCFields(); current_page->SetAllocationWatermark(allocation_info_.top); accounting_stats_.WasteBytes(page_extra_); SetAllocationInfo(&allocation_info_, next_page); return AllocateLinearly(&allocation_info_, size_in_bytes); } void FixedSpace::DeallocateBlock(Address start, int size_in_bytes, bool add_to_freelist) { // Free-list elements in fixed space are assumed to have a fixed size. // We break the free block into chunks and add them to the free list // individually. int size = object_size_in_bytes(); ASSERT(size_in_bytes % size == 0); Address end = start + size_in_bytes; for (Address a = start; a < end; a += size) { Free(a, add_to_freelist); } } #ifdef DEBUG void FixedSpace::ReportStatistics() { int pct = static_cast(Available() * 100 / Capacity()); PrintF(" capacity: %" V8_PTR_PREFIX "d" ", waste: %" V8_PTR_PREFIX "d" ", available: %" V8_PTR_PREFIX "d, %%%d\n", Capacity(), Waste(), Available(), pct); ClearHistograms(); HeapObjectIterator obj_it(this); for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) CollectHistogramInfo(obj); ReportHistogram(false); } #endif // ----------------------------------------------------------------------------- // MapSpace implementation void MapSpace::PrepareForMarkCompact(bool will_compact) { // Call prepare of the super class. FixedSpace::PrepareForMarkCompact(will_compact); if (will_compact) { // Initialize map index entry. int page_count = 0; PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { ASSERT_MAP_PAGE_INDEX(page_count); Page* p = it.next(); ASSERT(p->mc_page_index == page_count); page_addresses_[page_count++] = p->address(); } } } #ifdef DEBUG void MapSpace::VerifyObject(HeapObject* object) { // The object should be a map or a free-list node. ASSERT(object->IsMap() || object->IsByteArray()); } #endif // ----------------------------------------------------------------------------- // GlobalPropertyCellSpace implementation #ifdef DEBUG void CellSpace::VerifyObject(HeapObject* object) { // The object should be a global object property cell or a free-list node. ASSERT(object->IsJSGlobalPropertyCell() || object->map() == heap()->two_pointer_filler_map()); } #endif // ----------------------------------------------------------------------------- // LargeObjectIterator LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) { current_ = space->first_chunk_; size_func_ = NULL; } LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space, HeapObjectCallback size_func) { current_ = space->first_chunk_; size_func_ = size_func; } HeapObject* LargeObjectIterator::next() { if (current_ == NULL) return NULL; HeapObject* object = current_->GetObject(); current_ = current_->next(); return object; } // ----------------------------------------------------------------------------- // LargeObjectChunk LargeObjectChunk* LargeObjectChunk::New(int size_in_bytes, Executability executable) { size_t requested = ChunkSizeFor(size_in_bytes); size_t size; size_t guard_size = (executable == EXECUTABLE) ? Page::kPageSize : 0; Isolate* isolate = Isolate::Current(); void* mem = isolate->memory_allocator()->AllocateRawMemory( requested + guard_size, &size, executable); if (mem == NULL) return NULL; // The start of the chunk may be overlayed with a page so we have to // make sure that the page flags fit in the size field. ASSERT((size & Page::kPageFlagMask) == 0); LOG(isolate, NewEvent("LargeObjectChunk", mem, size)); if (size < requested + guard_size) { isolate->memory_allocator()->FreeRawMemory( mem, size, executable); LOG(isolate, DeleteEvent("LargeObjectChunk", mem)); return NULL; } if (guard_size != 0) { OS::Guard(mem, guard_size); size -= guard_size; mem = static_cast
(mem) + guard_size; } ObjectSpace space = (executable == EXECUTABLE) ? kObjectSpaceCodeSpace : kObjectSpaceLoSpace; isolate->memory_allocator()->PerformAllocationCallback( space, kAllocationActionAllocate, size); LargeObjectChunk* chunk = reinterpret_cast(mem); chunk->size_ = size; chunk->GetPage()->heap_ = isolate->heap(); return chunk; } void LargeObjectChunk::Free(Executability executable) { size_t guard_size = (executable == EXECUTABLE) ? Page::kPageSize : 0; ObjectSpace space = (executable == EXECUTABLE) ? kObjectSpaceCodeSpace : kObjectSpaceLoSpace; // Do not access instance fields after FreeRawMemory! Address my_address = address(); size_t my_size = size(); Isolate* isolate = GetPage()->heap_->isolate(); MemoryAllocator* a = isolate->memory_allocator(); a->FreeRawMemory(my_address - guard_size, my_size + guard_size, executable); a->PerformAllocationCallback(space, kAllocationActionFree, my_size); LOG(isolate, DeleteEvent("LargeObjectChunk", my_address)); } int LargeObjectChunk::ChunkSizeFor(int size_in_bytes) { int os_alignment = static_cast(OS::AllocateAlignment()); if (os_alignment < Page::kPageSize) { size_in_bytes += (Page::kPageSize - os_alignment); } return size_in_bytes + Page::kObjectStartOffset; } // ----------------------------------------------------------------------------- // LargeObjectSpace LargeObjectSpace::LargeObjectSpace(Heap* heap, AllocationSpace id) : Space(heap, id, NOT_EXECUTABLE), // Managed on a per-allocation basis first_chunk_(NULL), size_(0), page_count_(0), objects_size_(0) {} bool LargeObjectSpace::Setup() { first_chunk_ = NULL; size_ = 0; page_count_ = 0; objects_size_ = 0; return true; } void LargeObjectSpace::TearDown() { while (first_chunk_ != NULL) { LargeObjectChunk* chunk = first_chunk_; first_chunk_ = first_chunk_->next(); chunk->Free(chunk->GetPage()->PageExecutability()); } Setup(); } MaybeObject* LargeObjectSpace::AllocateRawInternal(int requested_size, int object_size, Executability executable) { ASSERT(0 < object_size && object_size <= requested_size); // Check if we want to force a GC before growing the old space further. // If so, fail the allocation. if (!heap()->always_allocate() && heap()->OldGenerationAllocationLimitReached()) { return Failure::RetryAfterGC(identity()); } LargeObjectChunk* chunk = LargeObjectChunk::New(requested_size, executable); if (chunk == NULL) { return Failure::RetryAfterGC(identity()); } size_ += static_cast(chunk->size()); objects_size_ += requested_size; page_count_++; chunk->set_next(first_chunk_); first_chunk_ = chunk; // Initialize page header. Page* page = chunk->GetPage(); Address object_address = page->ObjectAreaStart(); // Clear the low order bit of the second word in the page to flag it as a // large object page. If the chunk_size happened to be written there, its // low order bit should already be clear. page->SetIsLargeObjectPage(true); page->SetPageExecutability(executable); page->SetRegionMarks(Page::kAllRegionsCleanMarks); return HeapObject::FromAddress(object_address); } MaybeObject* LargeObjectSpace::AllocateRawCode(int size_in_bytes) { ASSERT(0 < size_in_bytes); return AllocateRawInternal(size_in_bytes, size_in_bytes, EXECUTABLE); } MaybeObject* LargeObjectSpace::AllocateRawFixedArray(int size_in_bytes) { ASSERT(0 < size_in_bytes); return AllocateRawInternal(size_in_bytes, size_in_bytes, NOT_EXECUTABLE); } MaybeObject* LargeObjectSpace::AllocateRaw(int size_in_bytes) { ASSERT(0 < size_in_bytes); return AllocateRawInternal(size_in_bytes, size_in_bytes, NOT_EXECUTABLE); } // GC support MaybeObject* LargeObjectSpace::FindObject(Address a) { for (LargeObjectChunk* chunk = first_chunk_; chunk != NULL; chunk = chunk->next()) { Address chunk_address = chunk->address(); if (chunk_address <= a && a < chunk_address + chunk->size()) { return chunk->GetObject(); } } return Failure::Exception(); } LargeObjectChunk* LargeObjectSpace::FindChunkContainingPc(Address pc) { // TODO(853): Change this implementation to only find executable // chunks and use some kind of hash-based approach to speed it up. for (LargeObjectChunk* chunk = first_chunk_; chunk != NULL; chunk = chunk->next()) { Address chunk_address = chunk->address(); if (chunk_address <= pc && pc < chunk_address + chunk->size()) { return chunk; } } return NULL; } void LargeObjectSpace::IterateDirtyRegions(ObjectSlotCallback copy_object) { LargeObjectIterator it(this); for (HeapObject* object = it.next(); object != NULL; object = it.next()) { // We only have code, sequential strings, or fixed arrays in large // object space, and only fixed arrays can possibly contain pointers to // the young generation. if (object->IsFixedArray()) { Page* page = Page::FromAddress(object->address()); uint32_t marks = page->GetRegionMarks(); uint32_t newmarks = Page::kAllRegionsCleanMarks; if (marks != Page::kAllRegionsCleanMarks) { // For a large page a single dirty mark corresponds to several // regions (modulo 32). So we treat a large page as a sequence of // normal pages of size Page::kPageSize having same dirty marks // and subsequently iterate dirty regions on each of these pages. Address start = object->address(); Address end = page->ObjectAreaEnd(); Address object_end = start + object->Size(); // Iterate regions of the first normal page covering object. uint32_t first_region_number = page->GetRegionNumberForAddress(start); newmarks |= heap()->IterateDirtyRegions(marks >> first_region_number, start, end, &Heap::IteratePointersInDirtyRegion, copy_object) << first_region_number; start = end; end = start + Page::kPageSize; while (end <= object_end) { // Iterate next 32 regions. newmarks |= heap()->IterateDirtyRegions(marks, start, end, &Heap::IteratePointersInDirtyRegion, copy_object); start = end; end = start + Page::kPageSize; } if (start != object_end) { // Iterate the last piece of an object which is less than // Page::kPageSize. newmarks |= heap()->IterateDirtyRegions(marks, start, object_end, &Heap::IteratePointersInDirtyRegion, copy_object); } page->SetRegionMarks(newmarks); } } } } void LargeObjectSpace::FreeUnmarkedObjects() { LargeObjectChunk* previous = NULL; LargeObjectChunk* current = first_chunk_; while (current != NULL) { HeapObject* object = current->GetObject(); if (object->IsMarked()) { object->ClearMark(); heap()->mark_compact_collector()->tracer()->decrement_marked_count(); previous = current; current = current->next(); } else { // Cut the chunk out from the chunk list. LargeObjectChunk* current_chunk = current; current = current->next(); if (previous == NULL) { first_chunk_ = current; } else { previous->set_next(current); } // Free the chunk. heap()->mark_compact_collector()->ReportDeleteIfNeeded( object, heap()->isolate()); LiveObjectList::ProcessNonLive(object); size_ -= static_cast(current_chunk->size()); objects_size_ -= object->Size(); page_count_--; current_chunk->Free(current_chunk->GetPage()->PageExecutability()); } } } bool LargeObjectSpace::Contains(HeapObject* object) { Address address = object->address(); if (heap()->new_space()->Contains(address)) { return false; } Page* page = Page::FromAddress(address); SLOW_ASSERT(!page->IsLargeObjectPage() || !FindObject(address)->IsFailure()); return page->IsLargeObjectPage(); } #ifdef DEBUG // We do not assume that the large object iterator works, because it depends // on the invariants we are checking during verification. void LargeObjectSpace::Verify() { for (LargeObjectChunk* chunk = first_chunk_; chunk != NULL; chunk = chunk->next()) { // Each chunk contains an object that starts at the large object page's // object area start. HeapObject* object = chunk->GetObject(); Page* page = Page::FromAddress(object->address()); ASSERT(object->address() == page->ObjectAreaStart()); // The first word should be a map, and we expect all map pointers to be // in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(heap()->map_space()->Contains(map)); // We have only code, sequential strings, external strings // (sequential strings that have been morphed into external // strings), fixed arrays, and byte arrays in large object space. ASSERT(object->IsCode() || object->IsSeqString() || object->IsExternalString() || object->IsFixedArray() || object->IsFixedDoubleArray() || object->IsByteArray()); // The object itself should look OK. object->Verify(); // Byte arrays and strings don't have interior pointers. if (object->IsCode()) { VerifyPointersVisitor code_visitor; object->IterateBody(map->instance_type(), object->Size(), &code_visitor); } else if (object->IsFixedArray()) { // We loop over fixed arrays ourselves, rather then using the visitor, // because the visitor doesn't support the start/offset iteration // needed for IsRegionDirty. FixedArray* array = FixedArray::cast(object); for (int j = 0; j < array->length(); j++) { Object* element = array->get(j); if (element->IsHeapObject()) { HeapObject* element_object = HeapObject::cast(element); ASSERT(heap()->Contains(element_object)); ASSERT(element_object->map()->IsMap()); if (heap()->InNewSpace(element_object)) { Address array_addr = object->address(); Address element_addr = array_addr + FixedArray::kHeaderSize + j * kPointerSize; ASSERT(Page::FromAddress(array_addr)->IsRegionDirty(element_addr)); } } } } } } void LargeObjectSpace::Print() { LargeObjectIterator it(this); for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) { obj->Print(); } } void LargeObjectSpace::ReportStatistics() { PrintF(" size: %" V8_PTR_PREFIX "d\n", size_); int num_objects = 0; ClearHistograms(); LargeObjectIterator it(this); for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) { num_objects++; CollectHistogramInfo(obj); } PrintF(" number of objects %d, " "size of objects %" V8_PTR_PREFIX "d\n", num_objects, objects_size_); if (num_objects > 0) ReportHistogram(false); } void LargeObjectSpace::CollectCodeStatistics() { Isolate* isolate = heap()->isolate(); LargeObjectIterator obj_it(this); for (HeapObject* obj = obj_it.next(); obj != NULL; obj = obj_it.next()) { if (obj->IsCode()) { Code* code = Code::cast(obj); isolate->code_kind_statistics()[code->kind()] += code->Size(); } } } #endif // DEBUG } } // namespace v8::internal