| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/heap/spaces.h" |
| |
| #include <cinttypes> |
| #include <utility> |
| |
| #include "src/base/bits.h" |
| #include "src/base/lsan.h" |
| #include "src/base/macros.h" |
| #include "src/base/platform/semaphore.h" |
| #include "src/base/template-utils.h" |
| #include "src/execution/vm-state-inl.h" |
| #include "src/heap/array-buffer-tracker.h" |
| #include "src/heap/combined-heap.h" |
| #include "src/heap/concurrent-marking.h" |
| #include "src/heap/gc-tracer.h" |
| #include "src/heap/heap-controller.h" |
| #include "src/heap/incremental-marking-inl.h" |
| #include "src/heap/mark-compact.h" |
| #include "src/heap/read-only-heap.h" |
| #include "src/heap/remembered-set.h" |
| #include "src/heap/slot-set.h" |
| #include "src/heap/sweeper.h" |
| #include "src/init/v8.h" |
| #include "src/logging/counters.h" |
| #include "src/objects/free-space-inl.h" |
| #include "src/objects/js-array-buffer-inl.h" |
| #include "src/objects/objects-inl.h" |
| #include "src/sanitizer/msan.h" |
| #include "src/snapshot/snapshot.h" |
| #include "src/utils/ostreams.h" |
| |
| #if V8_OS_STARBOARD |
| #include "src/poems.h" |
| #endif |
| |
| namespace v8 { |
| namespace internal { |
| |
| // These checks are here to ensure that the lower 32 bits of any real heap |
| // object can't overlap with the lower 32 bits of cleared weak reference value |
| // and therefore it's enough to compare only the lower 32 bits of a MaybeObject |
| // in order to figure out if it's a cleared weak reference or not. |
| STATIC_ASSERT(kClearedWeakHeapObjectLower32 > 0); |
| STATIC_ASSERT(kClearedWeakHeapObjectLower32 < Page::kHeaderSize); |
| STATIC_ASSERT(kClearedWeakHeapObjectLower32 < LargePage::kHeaderSize); |
| |
| // ---------------------------------------------------------------------------- |
| // PagedSpaceObjectIterator |
| |
| PagedSpaceObjectIterator::PagedSpaceObjectIterator(PagedSpace* space) |
| : cur_addr_(kNullAddress), |
| cur_end_(kNullAddress), |
| space_(space), |
| page_range_(space->first_page(), nullptr), |
| current_page_(page_range_.begin()) { |
| #ifdef V8_SHARED_RO_HEAP |
| DCHECK_NE(space->identity(), RO_SPACE); |
| #endif |
| } |
| |
| PagedSpaceObjectIterator::PagedSpaceObjectIterator(Page* page) |
| : cur_addr_(kNullAddress), |
| cur_end_(kNullAddress), |
| space_(reinterpret_cast<PagedSpace*>(page->owner())), |
| page_range_(page), |
| current_page_(page_range_.begin()) { |
| #ifdef V8_SHARED_RO_HEAP |
| // TODO(v8:7464): Always enforce this once PagedSpace::Verify is no longer |
| // used to verify read-only space for non-shared builds. |
| DCHECK(!page->InReadOnlySpace()); |
| #endif // V8_SHARED_RO_HEAP |
| |
| #ifdef DEBUG |
| AllocationSpace owner = page->owner_identity(); |
| DCHECK(owner == RO_SPACE || owner == OLD_SPACE || owner == MAP_SPACE || |
| owner == CODE_SPACE); |
| #endif // DEBUG |
| } |
| |
| // We have hit the end of the page and should advance to the next block of |
| // objects. This happens at the end of the page. |
| bool PagedSpaceObjectIterator::AdvanceToNextPage() { |
| DCHECK_EQ(cur_addr_, cur_end_); |
| if (current_page_ == page_range_.end()) return false; |
| Page* cur_page = *(current_page_++); |
| |
| #ifdef ENABLE_MINOR_MC |
| Heap* heap = space_->heap(); |
| heap->mark_compact_collector()->sweeper()->EnsurePageIsIterable(cur_page); |
| if (cur_page->IsFlagSet(Page::SWEEP_TO_ITERATE)) { |
| heap->minor_mark_compact_collector()->MakeIterable( |
| cur_page, MarkingTreatmentMode::CLEAR, |
| FreeSpaceTreatmentMode::IGNORE_FREE_SPACE); |
| } |
| #else |
| DCHECK(!cur_page->IsFlagSet(Page::SWEEP_TO_ITERATE)); |
| #endif // ENABLE_MINOR_MC |
| |
| cur_addr_ = cur_page->area_start(); |
| cur_end_ = cur_page->area_end(); |
| DCHECK(cur_page->SweepingDone()); |
| return true; |
| } |
| |
| PauseAllocationObserversScope::PauseAllocationObserversScope(Heap* heap) |
| : heap_(heap) { |
| DCHECK_EQ(heap->gc_state(), Heap::NOT_IN_GC); |
| |
| for (SpaceIterator it(heap_); it.HasNext();) { |
| it.Next()->PauseAllocationObservers(); |
| } |
| } |
| |
| PauseAllocationObserversScope::~PauseAllocationObserversScope() { |
| for (SpaceIterator it(heap_); it.HasNext();) { |
| it.Next()->ResumeAllocationObservers(); |
| } |
| } |
| |
| static base::LazyInstance<CodeRangeAddressHint>::type code_range_address_hint = |
| LAZY_INSTANCE_INITIALIZER; |
| |
| Address CodeRangeAddressHint::GetAddressHint(size_t code_range_size) { |
| base::MutexGuard guard(&mutex_); |
| auto it = recently_freed_.find(code_range_size); |
| if (it == recently_freed_.end() || it->second.empty()) { |
| return reinterpret_cast<Address>(GetRandomMmapAddr()); |
| } |
| Address result = it->second.back(); |
| it->second.pop_back(); |
| return result; |
| } |
| |
| void CodeRangeAddressHint::NotifyFreedCodeRange(Address code_range_start, |
| size_t code_range_size) { |
| base::MutexGuard guard(&mutex_); |
| recently_freed_[code_range_size].push_back(code_range_start); |
| } |
| |
| // ----------------------------------------------------------------------------- |
| // MemoryAllocator |
| // |
| |
| MemoryAllocator::MemoryAllocator(Isolate* isolate, size_t capacity, |
| size_t code_range_size) |
| : isolate_(isolate), |
| data_page_allocator_(isolate->page_allocator()), |
| code_page_allocator_(nullptr), |
| capacity_(RoundUp(capacity, Page::kPageSize)), |
| size_(0), |
| size_executable_(0), |
| lowest_ever_allocated_(static_cast<Address>(-1ll)), |
| highest_ever_allocated_(kNullAddress), |
| unmapper_(isolate->heap(), this) { |
| InitializeCodePageAllocator(data_page_allocator_, code_range_size); |
| } |
| |
| void MemoryAllocator::InitializeCodePageAllocator( |
| v8::PageAllocator* page_allocator, size_t requested) { |
| DCHECK_NULL(code_page_allocator_instance_.get()); |
| |
| code_page_allocator_ = page_allocator; |
| |
| if (requested == 0) { |
| if (!kRequiresCodeRange) return; |
| // When a target requires the code range feature, we put all code objects |
| // in a kMaximalCodeRangeSize range of virtual address space, so that |
| // they can call each other with near calls. |
| requested = kMaximalCodeRangeSize; |
| } else if (requested <= kMinimumCodeRangeSize) { |
| requested = kMinimumCodeRangeSize; |
| } |
| |
| const size_t reserved_area = |
| kReservedCodeRangePages * MemoryAllocator::GetCommitPageSize(); |
| if (requested < (kMaximalCodeRangeSize - reserved_area)) { |
| requested += RoundUp(reserved_area, MemoryChunk::kPageSize); |
| // Fullfilling both reserved pages requirement and huge code area |
| // alignments is not supported (requires re-implementation). |
| DCHECK_LE(kMinExpectedOSPageSize, page_allocator->AllocatePageSize()); |
| } |
| DCHECK(!kRequiresCodeRange || requested <= kMaximalCodeRangeSize); |
| |
| Address hint = |
| RoundDown(code_range_address_hint.Pointer()->GetAddressHint(requested), |
| page_allocator->AllocatePageSize()); |
| VirtualMemory reservation( |
| page_allocator, requested, reinterpret_cast<void*>(hint), |
| Max(kMinExpectedOSPageSize, page_allocator->AllocatePageSize())); |
| if (!reservation.IsReserved()) { |
| V8::FatalProcessOutOfMemory(isolate_, |
| "CodeRange setup: allocate virtual memory"); |
| } |
| code_range_ = reservation.region(); |
| |
| // We are sure that we have mapped a block of requested addresses. |
| DCHECK_GE(reservation.size(), requested); |
| Address base = reservation.address(); |
| |
| // On some platforms, specifically Win64, we need to reserve some pages at |
| // the beginning of an executable space. See |
| // https://cs.chromium.org/chromium/src/components/crash/content/ |
| // app/crashpad_win.cc?rcl=fd680447881449fba2edcf0589320e7253719212&l=204 |
| // for details. |
| if (reserved_area > 0) { |
| if (!reservation.SetPermissions(base, reserved_area, |
| PageAllocator::kReadWrite)) |
| V8::FatalProcessOutOfMemory(isolate_, "CodeRange setup: set permissions"); |
| |
| base += reserved_area; |
| } |
| Address aligned_base = RoundUp(base, MemoryChunk::kAlignment); |
| size_t size = |
| RoundDown(reservation.size() - (aligned_base - base) - reserved_area, |
| MemoryChunk::kPageSize); |
| DCHECK(IsAligned(aligned_base, kMinExpectedOSPageSize)); |
| |
| LOG(isolate_, |
| NewEvent("CodeRange", reinterpret_cast<void*>(reservation.address()), |
| requested)); |
| |
| heap_reservation_ = std::move(reservation); |
| code_page_allocator_instance_ = base::make_unique<base::BoundedPageAllocator>( |
| page_allocator, aligned_base, size, |
| static_cast<size_t>(MemoryChunk::kAlignment)); |
| code_page_allocator_ = code_page_allocator_instance_.get(); |
| } |
| |
| void MemoryAllocator::TearDown() { |
| unmapper()->TearDown(); |
| |
| // Check that spaces were torn down before MemoryAllocator. |
| DCHECK_EQ(size_, 0u); |
| // TODO(gc) this will be true again when we fix FreeMemory. |
| // DCHECK_EQ(0, size_executable_); |
| capacity_ = 0; |
| |
| if (last_chunk_.IsReserved()) { |
| last_chunk_.Free(); |
| } |
| |
| if (code_page_allocator_instance_.get()) { |
| DCHECK(!code_range_.is_empty()); |
| code_range_address_hint.Pointer()->NotifyFreedCodeRange(code_range_.begin(), |
| code_range_.size()); |
| code_range_ = base::AddressRegion(); |
| code_page_allocator_instance_.reset(); |
| } |
| code_page_allocator_ = nullptr; |
| data_page_allocator_ = nullptr; |
| } |
| |
| class MemoryAllocator::Unmapper::UnmapFreeMemoryTask : public CancelableTask { |
| public: |
| explicit UnmapFreeMemoryTask(Isolate* isolate, Unmapper* unmapper) |
| : CancelableTask(isolate), |
| unmapper_(unmapper), |
| tracer_(isolate->heap()->tracer()) {} |
| |
| private: |
| void RunInternal() override { |
| TRACE_BACKGROUND_GC(tracer_, |
| GCTracer::BackgroundScope::BACKGROUND_UNMAPPER); |
| unmapper_->PerformFreeMemoryOnQueuedChunks<FreeMode::kUncommitPooled>(); |
| unmapper_->active_unmapping_tasks_--; |
| unmapper_->pending_unmapping_tasks_semaphore_.Signal(); |
| if (FLAG_trace_unmapper) { |
| PrintIsolate(unmapper_->heap_->isolate(), |
| "UnmapFreeMemoryTask Done: id=%" PRIu64 "\n", id()); |
| } |
| } |
| |
| Unmapper* const unmapper_; |
| GCTracer* const tracer_; |
| DISALLOW_COPY_AND_ASSIGN(UnmapFreeMemoryTask); |
| }; |
| |
| void MemoryAllocator::Unmapper::FreeQueuedChunks() { |
| if (!heap_->IsTearingDown() && FLAG_concurrent_sweeping) { |
| if (!MakeRoomForNewTasks()) { |
| // kMaxUnmapperTasks are already running. Avoid creating any more. |
| if (FLAG_trace_unmapper) { |
| PrintIsolate(heap_->isolate(), |
| "Unmapper::FreeQueuedChunks: reached task limit (%d)\n", |
| kMaxUnmapperTasks); |
| } |
| return; |
| } |
| auto task = base::make_unique<UnmapFreeMemoryTask>(heap_->isolate(), this); |
| if (FLAG_trace_unmapper) { |
| PrintIsolate(heap_->isolate(), |
| "Unmapper::FreeQueuedChunks: new task id=%" PRIu64 "\n", |
| task->id()); |
| } |
| DCHECK_LT(pending_unmapping_tasks_, kMaxUnmapperTasks); |
| DCHECK_LE(active_unmapping_tasks_, pending_unmapping_tasks_); |
| DCHECK_GE(active_unmapping_tasks_, 0); |
| active_unmapping_tasks_++; |
| task_ids_[pending_unmapping_tasks_++] = task->id(); |
| V8::GetCurrentPlatform()->CallOnWorkerThread(std::move(task)); |
| } else { |
| PerformFreeMemoryOnQueuedChunks<FreeMode::kUncommitPooled>(); |
| } |
| } |
| |
| void MemoryAllocator::Unmapper::CancelAndWaitForPendingTasks() { |
| for (int i = 0; i < pending_unmapping_tasks_; i++) { |
| if (heap_->isolate()->cancelable_task_manager()->TryAbort(task_ids_[i]) != |
| TryAbortResult::kTaskAborted) { |
| pending_unmapping_tasks_semaphore_.Wait(); |
| } |
| } |
| pending_unmapping_tasks_ = 0; |
| active_unmapping_tasks_ = 0; |
| |
| if (FLAG_trace_unmapper) { |
| PrintIsolate( |
| heap_->isolate(), |
| "Unmapper::CancelAndWaitForPendingTasks: no tasks remaining\n"); |
| } |
| } |
| |
| void MemoryAllocator::Unmapper::PrepareForGC() { |
| // Free non-regular chunks because they cannot be re-used. |
| PerformFreeMemoryOnQueuedNonRegularChunks(); |
| } |
| |
| void MemoryAllocator::Unmapper::EnsureUnmappingCompleted() { |
| CancelAndWaitForPendingTasks(); |
| PerformFreeMemoryOnQueuedChunks<FreeMode::kReleasePooled>(); |
| } |
| |
| bool MemoryAllocator::Unmapper::MakeRoomForNewTasks() { |
| DCHECK_LE(pending_unmapping_tasks_, kMaxUnmapperTasks); |
| |
| if (active_unmapping_tasks_ == 0 && pending_unmapping_tasks_ > 0) { |
| // All previous unmapping tasks have been run to completion. |
| // Finalize those tasks to make room for new ones. |
| CancelAndWaitForPendingTasks(); |
| } |
| return pending_unmapping_tasks_ != kMaxUnmapperTasks; |
| } |
| |
| void MemoryAllocator::Unmapper::PerformFreeMemoryOnQueuedNonRegularChunks() { |
| MemoryChunk* chunk = nullptr; |
| while ((chunk = GetMemoryChunkSafe<kNonRegular>()) != nullptr) { |
| allocator_->PerformFreeMemory(chunk); |
| } |
| } |
| |
| template <MemoryAllocator::Unmapper::FreeMode mode> |
| void MemoryAllocator::Unmapper::PerformFreeMemoryOnQueuedChunks() { |
| MemoryChunk* chunk = nullptr; |
| if (FLAG_trace_unmapper) { |
| PrintIsolate( |
| heap_->isolate(), |
| "Unmapper::PerformFreeMemoryOnQueuedChunks: %d queued chunks\n", |
| NumberOfChunks()); |
| } |
| // Regular chunks. |
| while ((chunk = GetMemoryChunkSafe<kRegular>()) != nullptr) { |
| bool pooled = chunk->IsFlagSet(MemoryChunk::POOLED); |
| allocator_->PerformFreeMemory(chunk); |
| if (pooled) AddMemoryChunkSafe<kPooled>(chunk); |
| } |
| if (mode == MemoryAllocator::Unmapper::FreeMode::kReleasePooled) { |
| // The previous loop uncommitted any pages marked as pooled and added them |
| // to the pooled list. In case of kReleasePooled we need to free them |
| // though. |
| while ((chunk = GetMemoryChunkSafe<kPooled>()) != nullptr) { |
| allocator_->Free<MemoryAllocator::kAlreadyPooled>(chunk); |
| } |
| } |
| PerformFreeMemoryOnQueuedNonRegularChunks(); |
| } |
| |
| void MemoryAllocator::Unmapper::TearDown() { |
| CHECK_EQ(0, pending_unmapping_tasks_); |
| PerformFreeMemoryOnQueuedChunks<FreeMode::kReleasePooled>(); |
| for (int i = 0; i < kNumberOfChunkQueues; i++) { |
| DCHECK(chunks_[i].empty()); |
| } |
| } |
| |
| size_t MemoryAllocator::Unmapper::NumberOfCommittedChunks() { |
| base::MutexGuard guard(&mutex_); |
| return chunks_[kRegular].size() + chunks_[kNonRegular].size(); |
| } |
| |
| int MemoryAllocator::Unmapper::NumberOfChunks() { |
| base::MutexGuard guard(&mutex_); |
| size_t result = 0; |
| for (int i = 0; i < kNumberOfChunkQueues; i++) { |
| result += chunks_[i].size(); |
| } |
| return static_cast<int>(result); |
| } |
| |
| size_t MemoryAllocator::Unmapper::CommittedBufferedMemory() { |
| base::MutexGuard guard(&mutex_); |
| |
| size_t sum = 0; |
| // kPooled chunks are already uncommited. We only have to account for |
| // kRegular and kNonRegular chunks. |
| for (auto& chunk : chunks_[kRegular]) { |
| sum += chunk->size(); |
| } |
| for (auto& chunk : chunks_[kNonRegular]) { |
| sum += chunk->size(); |
| } |
| return sum; |
| } |
| |
| bool MemoryAllocator::CommitMemory(VirtualMemory* reservation) { |
| Address base = reservation->address(); |
| size_t size = reservation->size(); |
| if (!reservation->SetPermissions(base, size, PageAllocator::kReadWrite)) { |
| return false; |
| } |
| UpdateAllocatedSpaceLimits(base, base + size); |
| isolate_->counters()->memory_allocated()->Increment(static_cast<int>(size)); |
| return true; |
| } |
| |
| bool MemoryAllocator::UncommitMemory(VirtualMemory* reservation) { |
| size_t size = reservation->size(); |
| if (!reservation->SetPermissions(reservation->address(), size, |
| PageAllocator::kNoAccess)) { |
| return false; |
| } |
| isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size)); |
| return true; |
| } |
| |
| void MemoryAllocator::FreeMemory(v8::PageAllocator* page_allocator, |
| Address base, size_t size) { |
| CHECK(FreePages(page_allocator, reinterpret_cast<void*>(base), size)); |
| } |
| |
| Address MemoryAllocator::AllocateAlignedMemory( |
| size_t reserve_size, size_t commit_size, size_t alignment, |
| Executability executable, void* hint, VirtualMemory* controller) { |
| v8::PageAllocator* page_allocator = this->page_allocator(executable); |
| DCHECK(commit_size <= reserve_size); |
| VirtualMemory reservation(page_allocator, reserve_size, hint, alignment); |
| if (!reservation.IsReserved()) return kNullAddress; |
| Address base = reservation.address(); |
| size_ += reservation.size(); |
| |
| if (executable == EXECUTABLE) { |
| if (!CommitExecutableMemory(&reservation, base, commit_size, |
| reserve_size)) { |
| base = kNullAddress; |
| } |
| } else { |
| if (reservation.SetPermissions(base, commit_size, |
| PageAllocator::kReadWrite)) { |
| UpdateAllocatedSpaceLimits(base, base + commit_size); |
| } else { |
| base = kNullAddress; |
| } |
| } |
| |
| if (base == kNullAddress) { |
| // Failed to commit the body. Free the mapping and any partially committed |
| // regions inside it. |
| reservation.Free(); |
| size_ -= reserve_size; |
| return kNullAddress; |
| } |
| |
| *controller = std::move(reservation); |
| return base; |
| } |
| |
| void MemoryChunk::DiscardUnusedMemory(Address addr, size_t size) { |
| base::AddressRegion memory_area = |
| MemoryAllocator::ComputeDiscardMemoryArea(addr, size); |
| if (memory_area.size() != 0) { |
| MemoryAllocator* memory_allocator = heap_->memory_allocator(); |
| v8::PageAllocator* page_allocator = |
| memory_allocator->page_allocator(executable()); |
| CHECK(page_allocator->DiscardSystemPages( |
| reinterpret_cast<void*>(memory_area.begin()), memory_area.size())); |
| } |
| } |
| |
| size_t MemoryChunkLayout::CodePageGuardStartOffset() { |
| // We are guarding code pages: the first OS page after the header |
| // will be protected as non-writable. |
| return ::RoundUp(Page::kHeaderSize, MemoryAllocator::GetCommitPageSize()); |
| } |
| |
| size_t MemoryChunkLayout::CodePageGuardSize() { |
| return MemoryAllocator::GetCommitPageSize(); |
| } |
| |
| intptr_t MemoryChunkLayout::ObjectStartOffsetInCodePage() { |
| // We are guarding code pages: the first OS page after the header |
| // will be protected as non-writable. |
| return CodePageGuardStartOffset() + CodePageGuardSize(); |
| } |
| |
| intptr_t MemoryChunkLayout::ObjectEndOffsetInCodePage() { |
| // We are guarding code pages: the last OS page will be protected as |
| // non-writable. |
| return Page::kPageSize - |
| static_cast<int>(MemoryAllocator::GetCommitPageSize()); |
| } |
| |
| size_t MemoryChunkLayout::AllocatableMemoryInCodePage() { |
| size_t memory = ObjectEndOffsetInCodePage() - ObjectStartOffsetInCodePage(); |
| DCHECK_LE(kMaxRegularHeapObjectSize, memory); |
| return memory; |
| } |
| |
| intptr_t MemoryChunkLayout::ObjectStartOffsetInDataPage() { |
| return RoundUp(MemoryChunk::kHeaderSize, kTaggedSize); |
| } |
| |
| size_t MemoryChunkLayout::ObjectStartOffsetInMemoryChunk( |
| AllocationSpace space) { |
| if (space == CODE_SPACE) { |
| return ObjectStartOffsetInCodePage(); |
| } |
| return ObjectStartOffsetInDataPage(); |
| } |
| |
| size_t MemoryChunkLayout::AllocatableMemoryInDataPage() { |
| size_t memory = MemoryChunk::kPageSize - ObjectStartOffsetInDataPage(); |
| DCHECK_LE(kMaxRegularHeapObjectSize, memory); |
| return memory; |
| } |
| |
| size_t MemoryChunkLayout::AllocatableMemoryInMemoryChunk( |
| AllocationSpace space) { |
| if (space == CODE_SPACE) { |
| return AllocatableMemoryInCodePage(); |
| } |
| return AllocatableMemoryInDataPage(); |
| } |
| |
| #ifdef THREAD_SANITIZER |
| void MemoryChunk::SynchronizedHeapLoad() { |
| CHECK(reinterpret_cast<Heap*>(base::Acquire_Load( |
| reinterpret_cast<base::AtomicWord*>(&heap_))) != nullptr || |
| InReadOnlySpace()); |
| } |
| #endif |
| |
| void MemoryChunk::InitializationMemoryFence() { |
| base::SeqCst_MemoryFence(); |
| #ifdef THREAD_SANITIZER |
| // Since TSAN does not process memory fences, we use the following annotation |
| // to tell TSAN that there is no data race when emitting a |
| // InitializationMemoryFence. Note that the other thread still needs to |
| // perform MemoryChunk::synchronized_heap(). |
| base::Release_Store(reinterpret_cast<base::AtomicWord*>(&heap_), |
| reinterpret_cast<base::AtomicWord>(heap_)); |
| #endif |
| } |
| |
| void MemoryChunk::DecrementWriteUnprotectCounterAndMaybeSetPermissions( |
| PageAllocator::Permission permission) { |
| DCHECK(permission == PageAllocator::kRead || |
| permission == PageAllocator::kReadExecute); |
| DCHECK(IsFlagSet(MemoryChunk::IS_EXECUTABLE)); |
| DCHECK(owner_identity() == CODE_SPACE || owner_identity() == CODE_LO_SPACE); |
| // Decrementing the write_unprotect_counter_ and changing the page |
| // protection mode has to be atomic. |
| base::MutexGuard guard(page_protection_change_mutex_); |
| if (write_unprotect_counter_ == 0) { |
| // This is a corner case that may happen when we have a |
| // CodeSpaceMemoryModificationScope open and this page was newly |
| // added. |
| return; |
| } |
| write_unprotect_counter_--; |
| DCHECK_LT(write_unprotect_counter_, kMaxWriteUnprotectCounter); |
| if (write_unprotect_counter_ == 0) { |
| Address protect_start = |
| address() + MemoryChunkLayout::ObjectStartOffsetInCodePage(); |
| size_t page_size = MemoryAllocator::GetCommitPageSize(); |
| DCHECK(IsAligned(protect_start, page_size)); |
| size_t protect_size = RoundUp(area_size(), page_size); |
| CHECK(reservation_.SetPermissions(protect_start, protect_size, permission)); |
| } |
| } |
| |
| void MemoryChunk::SetReadable() { |
| DecrementWriteUnprotectCounterAndMaybeSetPermissions(PageAllocator::kRead); |
| } |
| |
| void MemoryChunk::SetReadAndExecutable() { |
| DCHECK(!FLAG_jitless); |
| DecrementWriteUnprotectCounterAndMaybeSetPermissions( |
| PageAllocator::kReadExecute); |
| } |
| |
| void MemoryChunk::SetReadAndWritable() { |
| DCHECK(IsFlagSet(MemoryChunk::IS_EXECUTABLE)); |
| DCHECK(owner_identity() == CODE_SPACE || owner_identity() == CODE_LO_SPACE); |
| // Incrementing the write_unprotect_counter_ and changing the page |
| // protection mode has to be atomic. |
| base::MutexGuard guard(page_protection_change_mutex_); |
| write_unprotect_counter_++; |
| DCHECK_LE(write_unprotect_counter_, kMaxWriteUnprotectCounter); |
| if (write_unprotect_counter_ == 1) { |
| Address unprotect_start = |
| address() + MemoryChunkLayout::ObjectStartOffsetInCodePage(); |
| size_t page_size = MemoryAllocator::GetCommitPageSize(); |
| DCHECK(IsAligned(unprotect_start, page_size)); |
| size_t unprotect_size = RoundUp(area_size(), page_size); |
| CHECK(reservation_.SetPermissions(unprotect_start, unprotect_size, |
| PageAllocator::kReadWrite)); |
| } |
| } |
| |
| void CodeObjectRegistry::RegisterNewlyAllocatedCodeObject(Address code) { |
| auto result = code_object_registry_newly_allocated_.insert(code); |
| USE(result); |
| DCHECK(result.second); |
| } |
| |
| void CodeObjectRegistry::RegisterAlreadyExistingCodeObject(Address code) { |
| code_object_registry_already_existing_.push_back(code); |
| } |
| |
| void CodeObjectRegistry::Clear() { |
| code_object_registry_already_existing_.clear(); |
| code_object_registry_newly_allocated_.clear(); |
| } |
| |
| void CodeObjectRegistry::Finalize() { |
| code_object_registry_already_existing_.shrink_to_fit(); |
| } |
| |
| bool CodeObjectRegistry::Contains(Address object) const { |
| return (code_object_registry_newly_allocated_.find(object) != |
| code_object_registry_newly_allocated_.end()) || |
| (std::binary_search(code_object_registry_already_existing_.begin(), |
| code_object_registry_already_existing_.end(), |
| object)); |
| } |
| |
| Address CodeObjectRegistry::GetCodeObjectStartFromInnerAddress( |
| Address address) const { |
| // Let's first find the object which comes right before address in the vector |
| // of already existing code objects. |
| Address already_existing_set_ = 0; |
| Address newly_allocated_set_ = 0; |
| if (!code_object_registry_already_existing_.empty()) { |
| auto it = |
| std::upper_bound(code_object_registry_already_existing_.begin(), |
| code_object_registry_already_existing_.end(), address); |
| if (it != code_object_registry_already_existing_.begin()) { |
| already_existing_set_ = *(--it); |
| } |
| } |
| |
| // Next, let's find the object which comes right before address in the set |
| // of newly allocated code objects. |
| if (!code_object_registry_newly_allocated_.empty()) { |
| auto it = code_object_registry_newly_allocated_.upper_bound(address); |
| if (it != code_object_registry_newly_allocated_.begin()) { |
| newly_allocated_set_ = *(--it); |
| } |
| } |
| |
| // The code objects which contains address has to be in one of the two |
| // data structures. |
| DCHECK(already_existing_set_ != 0 || newly_allocated_set_ != 0); |
| |
| // The address which is closest to the given address is the code object. |
| return already_existing_set_ > newly_allocated_set_ ? already_existing_set_ |
| : newly_allocated_set_; |
| } |
| |
| namespace { |
| |
| PageAllocator::Permission DefaultWritableCodePermissions() { |
| return FLAG_jitless ? PageAllocator::kReadWrite |
| : PageAllocator::kReadWriteExecute; |
| } |
| |
| } // namespace |
| |
| MemoryChunk* MemoryChunk::Initialize(Heap* heap, Address base, size_t size, |
| Address area_start, Address area_end, |
| Executability executable, Space* owner, |
| VirtualMemory reservation) { |
| MemoryChunk* chunk = FromAddress(base); |
| DCHECK_EQ(base, chunk->address()); |
| new (chunk) BasicMemoryChunk(size, area_start, area_end); |
| DCHECK(HasHeaderSentinel(area_start)); |
| |
| chunk->heap_ = heap; |
| chunk->set_owner(owner); |
| chunk->InitializeReservedMemory(); |
| base::AsAtomicPointer::Release_Store(&chunk->slot_set_[OLD_TO_NEW], nullptr); |
| base::AsAtomicPointer::Release_Store(&chunk->slot_set_[OLD_TO_OLD], nullptr); |
| base::AsAtomicPointer::Release_Store(&chunk->typed_slot_set_[OLD_TO_NEW], |
| nullptr); |
| base::AsAtomicPointer::Release_Store(&chunk->typed_slot_set_[OLD_TO_OLD], |
| nullptr); |
| chunk->invalidated_slots_ = nullptr; |
| chunk->progress_bar_ = 0; |
| chunk->high_water_mark_ = static_cast<intptr_t>(area_start - base); |
| chunk->set_concurrent_sweeping_state(kSweepingDone); |
| chunk->page_protection_change_mutex_ = new base::Mutex(); |
| chunk->write_unprotect_counter_ = 0; |
| chunk->mutex_ = new base::Mutex(); |
| chunk->allocated_bytes_ = chunk->area_size(); |
| chunk->wasted_memory_ = 0; |
| chunk->young_generation_bitmap_ = nullptr; |
| chunk->local_tracker_ = nullptr; |
| |
| chunk->external_backing_store_bytes_[ExternalBackingStoreType::kArrayBuffer] = |
| 0; |
| chunk->external_backing_store_bytes_ |
| [ExternalBackingStoreType::kExternalString] = 0; |
| |
| chunk->categories_ = nullptr; |
| |
| heap->incremental_marking()->non_atomic_marking_state()->SetLiveBytes(chunk, |
| 0); |
| if (owner->identity() == RO_SPACE) { |
| heap->incremental_marking() |
| ->non_atomic_marking_state() |
| ->bitmap(chunk) |
| ->MarkAllBits(); |
| chunk->SetFlag(READ_ONLY_HEAP); |
| } |
| |
| if (executable == EXECUTABLE) { |
| chunk->SetFlag(IS_EXECUTABLE); |
| if (heap->write_protect_code_memory()) { |
| chunk->write_unprotect_counter_ = |
| heap->code_space_memory_modification_scope_depth(); |
| } else { |
| size_t page_size = MemoryAllocator::GetCommitPageSize(); |
| DCHECK(IsAligned(area_start, page_size)); |
| size_t area_size = RoundUp(area_end - area_start, page_size); |
| CHECK(reservation.SetPermissions(area_start, area_size, |
| DefaultWritableCodePermissions())); |
| } |
| } |
| |
| chunk->reservation_ = std::move(reservation); |
| |
| if (owner->identity() == CODE_SPACE) { |
| chunk->code_object_registry_ = new CodeObjectRegistry(); |
| } else { |
| chunk->code_object_registry_ = nullptr; |
| } |
| |
| return chunk; |
| } |
| |
| Page* PagedSpace::InitializePage(MemoryChunk* chunk) { |
| Page* page = static_cast<Page*>(chunk); |
| DCHECK_EQ( |
| MemoryChunkLayout::AllocatableMemoryInMemoryChunk(page->owner_identity()), |
| page->area_size()); |
| // Make sure that categories are initialized before freeing the area. |
| page->ResetAllocationStatistics(); |
| page->SetOldGenerationPageFlags(heap()->incremental_marking()->IsMarking()); |
| page->AllocateFreeListCategories(); |
| page->InitializeFreeListCategories(); |
| page->list_node().Initialize(); |
| page->InitializationMemoryFence(); |
| return page; |
| } |
| |
| Page* SemiSpace::InitializePage(MemoryChunk* chunk) { |
| bool in_to_space = (id() != kFromSpace); |
| chunk->SetFlag(in_to_space ? MemoryChunk::TO_PAGE : MemoryChunk::FROM_PAGE); |
| Page* page = static_cast<Page*>(chunk); |
| page->SetYoungGenerationPageFlags(heap()->incremental_marking()->IsMarking()); |
| page->AllocateLocalTracker(); |
| page->list_node().Initialize(); |
| #ifdef ENABLE_MINOR_MC |
| if (FLAG_minor_mc) { |
| page->AllocateYoungGenerationBitmap(); |
| heap() |
| ->minor_mark_compact_collector() |
| ->non_atomic_marking_state() |
| ->ClearLiveness(page); |
| } |
| #endif // ENABLE_MINOR_MC |
| page->InitializationMemoryFence(); |
| return page; |
| } |
| |
| LargePage* LargePage::Initialize(Heap* heap, MemoryChunk* chunk, |
| Executability executable) { |
| if (executable && chunk->size() > LargePage::kMaxCodePageSize) { |
| STATIC_ASSERT(LargePage::kMaxCodePageSize <= TypedSlotSet::kMaxOffset); |
| FATAL("Code page is too large."); |
| } |
| |
| MSAN_ALLOCATED_UNINITIALIZED_MEMORY(chunk->area_start(), chunk->area_size()); |
| |
| // Initialize the sentinel value for each page boundary since the mutator |
| // may initialize the object starting from its end. |
| Address sentinel = chunk->address() + MemoryChunk::kHeaderSentinelOffset + |
| MemoryChunk::kPageSize; |
| while (sentinel < chunk->area_end()) { |
| *reinterpret_cast<intptr_t*>(sentinel) = kNullAddress; |
| sentinel += MemoryChunk::kPageSize; |
| } |
| |
| LargePage* page = static_cast<LargePage*>(chunk); |
| page->SetFlag(MemoryChunk::LARGE_PAGE); |
| page->list_node().Initialize(); |
| return page; |
| } |
| |
| void Page::AllocateFreeListCategories() { |
| DCHECK_NULL(categories_); |
| categories_ = new FreeListCategory*[free_list()->number_of_categories()](); |
| for (int i = kFirstCategory; i <= free_list()->last_category(); i++) { |
| DCHECK_NULL(categories_[i]); |
| categories_[i] = new FreeListCategory( |
| reinterpret_cast<PagedSpace*>(owner())->free_list(), this); |
| } |
| } |
| |
| void Page::InitializeFreeListCategories() { |
| for (int i = kFirstCategory; i <= free_list()->last_category(); i++) { |
| categories_[i]->Initialize(static_cast<FreeListCategoryType>(i)); |
| } |
| } |
| |
| void Page::ReleaseFreeListCategories() { |
| if (categories_ != nullptr) { |
| for (int i = kFirstCategory; i <= free_list()->last_category(); i++) { |
| if (categories_[i] != nullptr) { |
| delete categories_[i]; |
| categories_[i] = nullptr; |
| } |
| } |
| delete[] categories_; |
| categories_ = nullptr; |
| } |
| } |
| |
| Page* Page::ConvertNewToOld(Page* old_page) { |
| DCHECK(old_page); |
| DCHECK(old_page->InNewSpace()); |
| OldSpace* old_space = old_page->heap()->old_space(); |
| old_page->set_owner(old_space); |
| old_page->SetFlags(0, static_cast<uintptr_t>(~0)); |
| Page* new_page = old_space->InitializePage(old_page); |
| old_space->AddPage(new_page); |
| return new_page; |
| } |
| |
| size_t MemoryChunk::CommittedPhysicalMemory() { |
| if (!base::OS::HasLazyCommits() || owner_identity() == LO_SPACE) |
| return size(); |
| return high_water_mark_; |
| } |
| |
| bool MemoryChunk::InOldSpace() const { return owner_identity() == OLD_SPACE; } |
| |
| bool MemoryChunk::InLargeObjectSpace() const { |
| return owner_identity() == LO_SPACE; |
| } |
| |
| MemoryChunk* MemoryAllocator::AllocateChunk(size_t reserve_area_size, |
| size_t commit_area_size, |
| Executability executable, |
| Space* owner) { |
| DCHECK_LE(commit_area_size, reserve_area_size); |
| |
| size_t chunk_size; |
| Heap* heap = isolate_->heap(); |
| Address base = kNullAddress; |
| VirtualMemory reservation; |
| Address area_start = kNullAddress; |
| Address area_end = kNullAddress; |
| void* address_hint = |
| AlignedAddress(heap->GetRandomMmapAddr(), MemoryChunk::kAlignment); |
| |
| // |
| // MemoryChunk layout: |
| // |
| // Executable |
| // +----------------------------+<- base aligned with MemoryChunk::kAlignment |
| // | Header | |
| // +----------------------------+<- base + CodePageGuardStartOffset |
| // | Guard | |
| // +----------------------------+<- area_start_ |
| // | Area | |
| // +----------------------------+<- area_end_ (area_start + commit_area_size) |
| // | Committed but not used | |
| // +----------------------------+<- aligned at OS page boundary |
| // | Reserved but not committed | |
| // +----------------------------+<- aligned at OS page boundary |
| // | Guard | |
| // +----------------------------+<- base + chunk_size |
| // |
| // Non-executable |
| // +----------------------------+<- base aligned with MemoryChunk::kAlignment |
| // | Header | |
| // +----------------------------+<- area_start_ (base + area_start_) |
| // | Area | |
| // +----------------------------+<- area_end_ (area_start + commit_area_size) |
| // | Committed but not used | |
| // +----------------------------+<- aligned at OS page boundary |
| // | Reserved but not committed | |
| // +----------------------------+<- base + chunk_size |
| // |
| |
| if (executable == EXECUTABLE) { |
| chunk_size = ::RoundUp(MemoryChunkLayout::ObjectStartOffsetInCodePage() + |
| reserve_area_size + |
| MemoryChunkLayout::CodePageGuardSize(), |
| GetCommitPageSize()); |
| |
| // Size of header (not executable) plus area (executable). |
| size_t commit_size = ::RoundUp( |
| MemoryChunkLayout::CodePageGuardStartOffset() + commit_area_size, |
| GetCommitPageSize()); |
| base = |
| AllocateAlignedMemory(chunk_size, commit_size, MemoryChunk::kAlignment, |
| executable, address_hint, &reservation); |
| if (base == kNullAddress) return nullptr; |
| // Update executable memory size. |
| size_executable_ += reservation.size(); |
| |
| if (Heap::ShouldZapGarbage()) { |
| ZapBlock(base, MemoryChunkLayout::CodePageGuardStartOffset(), kZapValue); |
| ZapBlock(base + MemoryChunkLayout::ObjectStartOffsetInCodePage(), |
| commit_area_size, kZapValue); |
| } |
| |
| area_start = base + MemoryChunkLayout::ObjectStartOffsetInCodePage(); |
| area_end = area_start + commit_area_size; |
| } else { |
| chunk_size = ::RoundUp( |
| MemoryChunkLayout::ObjectStartOffsetInDataPage() + reserve_area_size, |
| GetCommitPageSize()); |
| size_t commit_size = ::RoundUp( |
| MemoryChunkLayout::ObjectStartOffsetInDataPage() + commit_area_size, |
| GetCommitPageSize()); |
| base = |
| AllocateAlignedMemory(chunk_size, commit_size, MemoryChunk::kAlignment, |
| executable, address_hint, &reservation); |
| |
| if (base == kNullAddress) return nullptr; |
| |
| if (Heap::ShouldZapGarbage()) { |
| ZapBlock( |
| base, |
| MemoryChunkLayout::ObjectStartOffsetInDataPage() + commit_area_size, |
| kZapValue); |
| } |
| |
| area_start = base + MemoryChunkLayout::ObjectStartOffsetInDataPage(); |
| area_end = area_start + commit_area_size; |
| } |
| |
| // Use chunk_size for statistics and callbacks because we assume that they |
| // treat reserved but not-yet committed memory regions of chunks as allocated. |
| isolate_->counters()->memory_allocated()->Increment( |
| static_cast<int>(chunk_size)); |
| |
| LOG(isolate_, |
| NewEvent("MemoryChunk", reinterpret_cast<void*>(base), chunk_size)); |
| |
| // We cannot use the last chunk in the address space because we would |
| // overflow when comparing top and limit if this chunk is used for a |
| // linear allocation area. |
| if ((base + chunk_size) == 0u) { |
| CHECK(!last_chunk_.IsReserved()); |
| last_chunk_ = std::move(reservation); |
| UncommitMemory(&last_chunk_); |
| size_ -= chunk_size; |
| if (executable == EXECUTABLE) { |
| size_executable_ -= chunk_size; |
| } |
| CHECK(last_chunk_.IsReserved()); |
| return AllocateChunk(reserve_area_size, commit_area_size, executable, |
| owner); |
| } |
| |
| MemoryChunk* chunk = |
| MemoryChunk::Initialize(heap, base, chunk_size, area_start, area_end, |
| executable, owner, std::move(reservation)); |
| |
| if (chunk->executable()) RegisterExecutableMemoryChunk(chunk); |
| return chunk; |
| } |
| |
| void MemoryChunk::SetOldGenerationPageFlags(bool is_marking) { |
| if (is_marking) { |
| SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| SetFlag(MemoryChunk::INCREMENTAL_MARKING); |
| } else { |
| ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| ClearFlag(MemoryChunk::INCREMENTAL_MARKING); |
| } |
| } |
| |
| void MemoryChunk::SetYoungGenerationPageFlags(bool is_marking) { |
| SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| if (is_marking) { |
| SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| SetFlag(MemoryChunk::INCREMENTAL_MARKING); |
| } else { |
| ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| ClearFlag(MemoryChunk::INCREMENTAL_MARKING); |
| } |
| } |
| |
| void Page::ResetAllocationStatistics() { |
| allocated_bytes_ = area_size(); |
| wasted_memory_ = 0; |
| } |
| |
| void Page::AllocateLocalTracker() { |
| DCHECK_NULL(local_tracker_); |
| local_tracker_ = new LocalArrayBufferTracker(this); |
| } |
| |
| bool Page::contains_array_buffers() { |
| return local_tracker_ != nullptr && !local_tracker_->IsEmpty(); |
| } |
| |
| size_t Page::AvailableInFreeList() { |
| size_t sum = 0; |
| ForAllFreeListCategories([&sum](FreeListCategory* category) { |
| sum += category->available(); |
| }); |
| return sum; |
| } |
| |
| #ifdef DEBUG |
| namespace { |
| // Skips filler starting from the given filler until the end address. |
| // Returns the first address after the skipped fillers. |
| Address SkipFillers(HeapObject filler, Address end) { |
| Address addr = filler.address(); |
| while (addr < end) { |
| filler = HeapObject::FromAddress(addr); |
| CHECK(filler.IsFiller()); |
| addr = filler.address() + filler.Size(); |
| } |
| return addr; |
| } |
| } // anonymous namespace |
| #endif // DEBUG |
| |
| size_t Page::ShrinkToHighWaterMark() { |
| // Shrinking only makes sense outside of the CodeRange, where we don't care |
| // about address space fragmentation. |
| VirtualMemory* reservation = reserved_memory(); |
| if (!reservation->IsReserved()) return 0; |
| |
| // Shrink pages to high water mark. The water mark points either to a filler |
| // or the area_end. |
| HeapObject filler = HeapObject::FromAddress(HighWaterMark()); |
| if (filler.address() == area_end()) return 0; |
| CHECK(filler.IsFiller()); |
| // Ensure that no objects were allocated in [filler, area_end) region. |
| DCHECK_EQ(area_end(), SkipFillers(filler, area_end())); |
| // Ensure that no objects will be allocated on this page. |
| DCHECK_EQ(0u, AvailableInFreeList()); |
| |
| size_t unused = RoundDown(static_cast<size_t>(area_end() - filler.address()), |
| MemoryAllocator::GetCommitPageSize()); |
| if (unused > 0) { |
| DCHECK_EQ(0u, unused % MemoryAllocator::GetCommitPageSize()); |
| if (FLAG_trace_gc_verbose) { |
| PrintIsolate(heap()->isolate(), "Shrinking page %p: end %p -> %p\n", |
| reinterpret_cast<void*>(this), |
| reinterpret_cast<void*>(area_end()), |
| reinterpret_cast<void*>(area_end() - unused)); |
| } |
| heap()->CreateFillerObjectAt( |
| filler.address(), |
| static_cast<int>(area_end() - filler.address() - unused), |
| ClearRecordedSlots::kNo); |
| heap()->memory_allocator()->PartialFreeMemory( |
| this, address() + size() - unused, unused, area_end() - unused); |
| if (filler.address() != area_end()) { |
| CHECK(filler.IsFiller()); |
| CHECK_EQ(filler.address() + filler.Size(), area_end()); |
| } |
| } |
| return unused; |
| } |
| |
| void Page::CreateBlackArea(Address start, Address end) { |
| DCHECK(heap()->incremental_marking()->black_allocation()); |
| DCHECK_EQ(Page::FromAddress(start), this); |
| DCHECK_NE(start, end); |
| DCHECK_EQ(Page::FromAddress(end - 1), this); |
| IncrementalMarking::MarkingState* marking_state = |
| heap()->incremental_marking()->marking_state(); |
| marking_state->bitmap(this)->SetRange(AddressToMarkbitIndex(start), |
| AddressToMarkbitIndex(end)); |
| marking_state->IncrementLiveBytes(this, static_cast<intptr_t>(end - start)); |
| } |
| |
| void Page::DestroyBlackArea(Address start, Address end) { |
| DCHECK(heap()->incremental_marking()->black_allocation()); |
| DCHECK_EQ(Page::FromAddress(start), this); |
| DCHECK_NE(start, end); |
| DCHECK_EQ(Page::FromAddress(end - 1), this); |
| IncrementalMarking::MarkingState* marking_state = |
| heap()->incremental_marking()->marking_state(); |
| marking_state->bitmap(this)->ClearRange(AddressToMarkbitIndex(start), |
| AddressToMarkbitIndex(end)); |
| marking_state->IncrementLiveBytes(this, -static_cast<intptr_t>(end - start)); |
| } |
| |
| void MemoryAllocator::PartialFreeMemory(MemoryChunk* chunk, Address start_free, |
| size_t bytes_to_free, |
| Address new_area_end) { |
| VirtualMemory* reservation = chunk->reserved_memory(); |
| DCHECK(reservation->IsReserved()); |
| chunk->set_size(chunk->size() - bytes_to_free); |
| chunk->set_area_end(new_area_end); |
| if (chunk->IsFlagSet(MemoryChunk::IS_EXECUTABLE)) { |
| // Add guard page at the end. |
| size_t page_size = GetCommitPageSize(); |
| DCHECK_EQ(0, chunk->area_end() % static_cast<Address>(page_size)); |
| DCHECK_EQ(chunk->address() + chunk->size(), |
| chunk->area_end() + MemoryChunkLayout::CodePageGuardSize()); |
| reservation->SetPermissions(chunk->area_end(), page_size, |
| PageAllocator::kNoAccess); |
| } |
| // On e.g. Windows, a reservation may be larger than a page and releasing |
| // partially starting at |start_free| will also release the potentially |
| // unused part behind the current page. |
| const size_t released_bytes = reservation->Release(start_free); |
| DCHECK_GE(size_, released_bytes); |
| size_ -= released_bytes; |
| isolate_->counters()->memory_allocated()->Decrement( |
| static_cast<int>(released_bytes)); |
| } |
| |
| void MemoryAllocator::UnregisterMemory(MemoryChunk* chunk) { |
| DCHECK(!chunk->IsFlagSet(MemoryChunk::UNREGISTERED)); |
| VirtualMemory* reservation = chunk->reserved_memory(); |
| const size_t size = |
| reservation->IsReserved() ? reservation->size() : chunk->size(); |
| DCHECK_GE(size_, static_cast<size_t>(size)); |
| size_ -= size; |
| isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size)); |
| if (chunk->executable() == EXECUTABLE) { |
| DCHECK_GE(size_executable_, size); |
| size_executable_ -= size; |
| } |
| |
| if (chunk->executable()) UnregisterExecutableMemoryChunk(chunk); |
| chunk->SetFlag(MemoryChunk::UNREGISTERED); |
| } |
| |
| void MemoryAllocator::PreFreeMemory(MemoryChunk* chunk) { |
| DCHECK(!chunk->IsFlagSet(MemoryChunk::PRE_FREED)); |
| LOG(isolate_, DeleteEvent("MemoryChunk", chunk)); |
| UnregisterMemory(chunk); |
| isolate_->heap()->RememberUnmappedPage(reinterpret_cast<Address>(chunk), |
| chunk->IsEvacuationCandidate()); |
| chunk->SetFlag(MemoryChunk::PRE_FREED); |
| } |
| |
| void MemoryAllocator::PerformFreeMemory(MemoryChunk* chunk) { |
| DCHECK(chunk->IsFlagSet(MemoryChunk::UNREGISTERED)); |
| DCHECK(chunk->IsFlagSet(MemoryChunk::PRE_FREED)); |
| chunk->ReleaseAllAllocatedMemory(); |
| |
| VirtualMemory* reservation = chunk->reserved_memory(); |
| if (chunk->IsFlagSet(MemoryChunk::POOLED)) { |
| UncommitMemory(reservation); |
| } else { |
| if (reservation->IsReserved()) { |
| reservation->Free(); |
| } else { |
| // Only read-only pages can have non-initialized reservation object. |
| DCHECK_EQ(RO_SPACE, chunk->owner_identity()); |
| FreeMemory(page_allocator(chunk->executable()), chunk->address(), |
| chunk->size()); |
| } |
| } |
| } |
| |
| template <MemoryAllocator::FreeMode mode> |
| void MemoryAllocator::Free(MemoryChunk* chunk) { |
| switch (mode) { |
| case kFull: |
| PreFreeMemory(chunk); |
| PerformFreeMemory(chunk); |
| break; |
| case kAlreadyPooled: |
| // Pooled pages cannot be touched anymore as their memory is uncommitted. |
| // Pooled pages are not-executable. |
| FreeMemory(data_page_allocator(), chunk->address(), |
| static_cast<size_t>(MemoryChunk::kPageSize)); |
| break; |
| case kPooledAndQueue: |
| DCHECK_EQ(chunk->size(), static_cast<size_t>(MemoryChunk::kPageSize)); |
| DCHECK_EQ(chunk->executable(), NOT_EXECUTABLE); |
| chunk->SetFlag(MemoryChunk::POOLED); |
| V8_FALLTHROUGH; |
| case kPreFreeAndQueue: |
| PreFreeMemory(chunk); |
| // The chunks added to this queue will be freed by a concurrent thread. |
| unmapper()->AddMemoryChunkSafe(chunk); |
| break; |
| } |
| } |
| |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void MemoryAllocator::Free< |
| MemoryAllocator::kFull>(MemoryChunk* chunk); |
| |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void MemoryAllocator::Free< |
| MemoryAllocator::kAlreadyPooled>(MemoryChunk* chunk); |
| |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void MemoryAllocator::Free< |
| MemoryAllocator::kPreFreeAndQueue>(MemoryChunk* chunk); |
| |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void MemoryAllocator::Free< |
| MemoryAllocator::kPooledAndQueue>(MemoryChunk* chunk); |
| |
| template <MemoryAllocator::AllocationMode alloc_mode, typename SpaceType> |
| Page* MemoryAllocator::AllocatePage(size_t size, SpaceType* owner, |
| Executability executable) { |
| MemoryChunk* chunk = nullptr; |
| if (alloc_mode == kPooled) { |
| DCHECK_EQ(size, static_cast<size_t>( |
| MemoryChunkLayout::AllocatableMemoryInMemoryChunk( |
| owner->identity()))); |
| DCHECK_EQ(executable, NOT_EXECUTABLE); |
| chunk = AllocatePagePooled(owner); |
| } |
| if (chunk == nullptr) { |
| chunk = AllocateChunk(size, size, executable, owner); |
| } |
| if (chunk == nullptr) return nullptr; |
| return owner->InitializePage(chunk); |
| } |
| |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) |
| Page* MemoryAllocator::AllocatePage<MemoryAllocator::kRegular, PagedSpace>( |
| size_t size, PagedSpace* owner, Executability executable); |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) |
| Page* MemoryAllocator::AllocatePage<MemoryAllocator::kRegular, SemiSpace>( |
| size_t size, SemiSpace* owner, Executability executable); |
| template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) |
| Page* MemoryAllocator::AllocatePage<MemoryAllocator::kPooled, SemiSpace>( |
| size_t size, SemiSpace* owner, Executability executable); |
| |
| LargePage* MemoryAllocator::AllocateLargePage(size_t size, |
| LargeObjectSpace* owner, |
| Executability executable) { |
| MemoryChunk* chunk = AllocateChunk(size, size, executable, owner); |
| if (chunk == nullptr) return nullptr; |
| return LargePage::Initialize(isolate_->heap(), chunk, executable); |
| } |
| |
| template <typename SpaceType> |
| MemoryChunk* MemoryAllocator::AllocatePagePooled(SpaceType* owner) { |
| MemoryChunk* chunk = unmapper()->TryGetPooledMemoryChunkSafe(); |
| if (chunk == nullptr) return nullptr; |
| const int size = MemoryChunk::kPageSize; |
| const Address start = reinterpret_cast<Address>(chunk); |
| const Address area_start = |
| start + |
| MemoryChunkLayout::ObjectStartOffsetInMemoryChunk(owner->identity()); |
| const Address area_end = start + size; |
| // Pooled pages are always regular data pages. |
| DCHECK_NE(CODE_SPACE, owner->identity()); |
| VirtualMemory reservation(data_page_allocator(), start, size); |
| if (!CommitMemory(&reservation)) return nullptr; |
| if (Heap::ShouldZapGarbage()) { |
| ZapBlock(start, size, kZapValue); |
| } |
| MemoryChunk::Initialize(isolate_->heap(), start, size, area_start, area_end, |
| NOT_EXECUTABLE, owner, std::move(reservation)); |
| size_ += size; |
| return chunk; |
| } |
| |
| void MemoryAllocator::ZapBlock(Address start, size_t size, |
| uintptr_t zap_value) { |
| DCHECK(IsAligned(start, kTaggedSize)); |
| DCHECK(IsAligned(size, kTaggedSize)); |
| MemsetTagged(ObjectSlot(start), Object(static_cast<Address>(zap_value)), |
| size >> kTaggedSizeLog2); |
| } |
| |
| intptr_t MemoryAllocator::GetCommitPageSize() { |
| if (FLAG_v8_os_page_size != 0) { |
| DCHECK(base::bits::IsPowerOfTwo(FLAG_v8_os_page_size)); |
| return FLAG_v8_os_page_size * KB; |
| } else { |
| return CommitPageSize(); |
| } |
| } |
| |
| base::AddressRegion MemoryAllocator::ComputeDiscardMemoryArea(Address addr, |
| size_t size) { |
| size_t page_size = MemoryAllocator::GetCommitPageSize(); |
| if (size < page_size + FreeSpace::kSize) { |
| return base::AddressRegion(0, 0); |
| } |
| Address discardable_start = RoundUp(addr + FreeSpace::kSize, page_size); |
| Address discardable_end = RoundDown(addr + size, page_size); |
| if (discardable_start >= discardable_end) return base::AddressRegion(0, 0); |
| return base::AddressRegion(discardable_start, |
| discardable_end - discardable_start); |
| } |
| |
| bool MemoryAllocator::CommitExecutableMemory(VirtualMemory* vm, Address start, |
| size_t commit_size, |
| size_t reserved_size) { |
| const size_t page_size = GetCommitPageSize(); |
| // All addresses and sizes must be aligned to the commit page size. |
| DCHECK(IsAligned(start, page_size)); |
| DCHECK_EQ(0, commit_size % page_size); |
| DCHECK_EQ(0, reserved_size % page_size); |
| const size_t guard_size = MemoryChunkLayout::CodePageGuardSize(); |
| const size_t pre_guard_offset = MemoryChunkLayout::CodePageGuardStartOffset(); |
| const size_t code_area_offset = |
| MemoryChunkLayout::ObjectStartOffsetInCodePage(); |
| // reserved_size includes two guard regions, commit_size does not. |
| DCHECK_LE(commit_size, reserved_size - 2 * guard_size); |
| const Address pre_guard_page = start + pre_guard_offset; |
| const Address code_area = start + code_area_offset; |
| const Address post_guard_page = start + reserved_size - guard_size; |
| // Commit the non-executable header, from start to pre-code guard page. |
| if (vm->SetPermissions(start, pre_guard_offset, PageAllocator::kReadWrite)) { |
| // Create the pre-code guard page, following the header. |
| if (vm->SetPermissions(pre_guard_page, page_size, |
| PageAllocator::kNoAccess)) { |
| // Commit the executable code body. |
| if (vm->SetPermissions(code_area, commit_size - pre_guard_offset, |
| PageAllocator::kReadWrite)) { |
| // Create the post-code guard page. |
| if (vm->SetPermissions(post_guard_page, page_size, |
| PageAllocator::kNoAccess)) { |
| UpdateAllocatedSpaceLimits(start, code_area + commit_size); |
| return true; |
| } |
| vm->SetPermissions(code_area, commit_size, PageAllocator::kNoAccess); |
| } |
| } |
| vm->SetPermissions(start, pre_guard_offset, PageAllocator::kNoAccess); |
| } |
| return false; |
| } |
| |
| |
| // ----------------------------------------------------------------------------- |
| // MemoryChunk implementation |
| |
| void MemoryChunk::ReleaseAllocatedMemoryNeededForWritableChunk() { |
| if (mutex_ != nullptr) { |
| delete mutex_; |
| mutex_ = nullptr; |
| } |
| if (page_protection_change_mutex_ != nullptr) { |
| delete page_protection_change_mutex_; |
| page_protection_change_mutex_ = nullptr; |
| } |
| if (code_object_registry_ != nullptr) { |
| delete code_object_registry_; |
| code_object_registry_ = nullptr; |
| } |
| |
| ReleaseSlotSet<OLD_TO_NEW>(); |
| ReleaseSlotSet<OLD_TO_OLD>(); |
| ReleaseTypedSlotSet<OLD_TO_NEW>(); |
| ReleaseTypedSlotSet<OLD_TO_OLD>(); |
| ReleaseInvalidatedSlots(); |
| |
| if (local_tracker_ != nullptr) ReleaseLocalTracker(); |
| if (young_generation_bitmap_ != nullptr) ReleaseYoungGenerationBitmap(); |
| } |
| |
| void MemoryChunk::ReleaseAllAllocatedMemory() { |
| if (!IsLargePage()) { |
| Page* page = static_cast<Page*>(this); |
| page->ReleaseFreeListCategories(); |
| } |
| |
| ReleaseAllocatedMemoryNeededForWritableChunk(); |
| if (marking_bitmap_ != nullptr) ReleaseMarkingBitmap(); |
| } |
| |
| static SlotSet* AllocateAndInitializeSlotSet(size_t size, Address page_start) { |
| size_t pages = (size + Page::kPageSize - 1) / Page::kPageSize; |
| DCHECK_LT(0, pages); |
| SlotSet* slot_set = new SlotSet[pages]; |
| for (size_t i = 0; i < pages; i++) { |
| slot_set[i].SetPageStart(page_start + i * Page::kPageSize); |
| } |
| return slot_set; |
| } |
| |
| template V8_EXPORT_PRIVATE SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_NEW>(); |
| template V8_EXPORT_PRIVATE SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_OLD>(); |
| |
| template <RememberedSetType type> |
| SlotSet* MemoryChunk::AllocateSlotSet() { |
| SlotSet* slot_set = AllocateAndInitializeSlotSet(size(), address()); |
| SlotSet* old_slot_set = base::AsAtomicPointer::Release_CompareAndSwap( |
| &slot_set_[type], nullptr, slot_set); |
| if (old_slot_set != nullptr) { |
| delete[] slot_set; |
| slot_set = old_slot_set; |
| } |
| DCHECK(slot_set); |
| return slot_set; |
| } |
| |
| template void MemoryChunk::ReleaseSlotSet<OLD_TO_NEW>(); |
| template void MemoryChunk::ReleaseSlotSet<OLD_TO_OLD>(); |
| |
| template <RememberedSetType type> |
| void MemoryChunk::ReleaseSlotSet() { |
| SlotSet* slot_set = slot_set_[type]; |
| if (slot_set) { |
| slot_set_[type] = nullptr; |
| delete[] slot_set; |
| } |
| } |
| |
| template TypedSlotSet* MemoryChunk::AllocateTypedSlotSet<OLD_TO_NEW>(); |
| template TypedSlotSet* MemoryChunk::AllocateTypedSlotSet<OLD_TO_OLD>(); |
| |
| template <RememberedSetType type> |
| TypedSlotSet* MemoryChunk::AllocateTypedSlotSet() { |
| TypedSlotSet* typed_slot_set = new TypedSlotSet(address()); |
| TypedSlotSet* old_value = base::AsAtomicPointer::Release_CompareAndSwap( |
| &typed_slot_set_[type], nullptr, typed_slot_set); |
| if (old_value != nullptr) { |
| delete typed_slot_set; |
| typed_slot_set = old_value; |
| } |
| DCHECK(typed_slot_set); |
| return typed_slot_set; |
| } |
| |
| template void MemoryChunk::ReleaseTypedSlotSet<OLD_TO_NEW>(); |
| template void MemoryChunk::ReleaseTypedSlotSet<OLD_TO_OLD>(); |
| |
| template <RememberedSetType type> |
| void MemoryChunk::ReleaseTypedSlotSet() { |
| TypedSlotSet* typed_slot_set = typed_slot_set_[type]; |
| if (typed_slot_set) { |
| typed_slot_set_[type] = nullptr; |
| delete typed_slot_set; |
| } |
| } |
| |
| InvalidatedSlots* MemoryChunk::AllocateInvalidatedSlots() { |
| DCHECK_NULL(invalidated_slots_); |
| invalidated_slots_ = new InvalidatedSlots(); |
| return invalidated_slots_; |
| } |
| |
| void MemoryChunk::ReleaseInvalidatedSlots() { |
| if (invalidated_slots_) { |
| delete invalidated_slots_; |
| invalidated_slots_ = nullptr; |
| } |
| } |
| |
| void MemoryChunk::RegisterObjectWithInvalidatedSlots(HeapObject object, |
| int size) { |
| if (!ShouldSkipEvacuationSlotRecording()) { |
| if (invalidated_slots() == nullptr) { |
| AllocateInvalidatedSlots(); |
| } |
| int old_size = (*invalidated_slots())[object]; |
| (*invalidated_slots())[object] = std::max(old_size, size); |
| } |
| } |
| |
| bool MemoryChunk::RegisteredObjectWithInvalidatedSlots(HeapObject object) { |
| if (ShouldSkipEvacuationSlotRecording()) { |
| // Invalidated slots do not matter if we are not recording slots. |
| return true; |
| } |
| if (invalidated_slots() == nullptr) { |
| return false; |
| } |
| return invalidated_slots()->find(object) != invalidated_slots()->end(); |
| } |
| |
| void MemoryChunk::MoveObjectWithInvalidatedSlots(HeapObject old_start, |
| HeapObject new_start) { |
| DCHECK_LT(old_start, new_start); |
| DCHECK_EQ(MemoryChunk::FromHeapObject(old_start), |
| MemoryChunk::FromHeapObject(new_start)); |
| if (!ShouldSkipEvacuationSlotRecording() && invalidated_slots()) { |
| auto it = invalidated_slots()->find(old_start); |
| if (it != invalidated_slots()->end()) { |
| int old_size = it->second; |
| int delta = static_cast<int>(new_start.address() - old_start.address()); |
| invalidated_slots()->erase(it); |
| (*invalidated_slots())[new_start] = old_size - delta; |
| } |
| } |
| } |
| |
| void MemoryChunk::ReleaseLocalTracker() { |
| DCHECK_NOT_NULL(local_tracker_); |
| delete local_tracker_; |
| local_tracker_ = nullptr; |
| } |
| |
| void MemoryChunk::AllocateYoungGenerationBitmap() { |
| DCHECK_NULL(young_generation_bitmap_); |
| young_generation_bitmap_ = static_cast<Bitmap*>(calloc(1, Bitmap::kSize)); |
| } |
| |
| void MemoryChunk::ReleaseYoungGenerationBitmap() { |
| DCHECK_NOT_NULL(young_generation_bitmap_); |
| free(young_generation_bitmap_); |
| young_generation_bitmap_ = nullptr; |
| } |
| |
| // ----------------------------------------------------------------------------- |
| // PagedSpace implementation |
| |
| void Space::CheckOffsetsAreConsistent() const { |
| DCHECK_EQ(Space::kIdOffset, OFFSET_OF(Space, id_)); |
| } |
| |
| void Space::AddAllocationObserver(AllocationObserver* observer) { |
| allocation_observers_.push_back(observer); |
| StartNextInlineAllocationStep(); |
| } |
| |
| void Space::RemoveAllocationObserver(AllocationObserver* observer) { |
| auto it = std::find(allocation_observers_.begin(), |
| allocation_observers_.end(), observer); |
| DCHECK(allocation_observers_.end() != it); |
| allocation_observers_.erase(it); |
| StartNextInlineAllocationStep(); |
| } |
| |
| void Space::PauseAllocationObservers() { allocation_observers_paused_ = true; } |
| |
| void Space::ResumeAllocationObservers() { |
| allocation_observers_paused_ = false; |
| } |
| |
| void Space::AllocationStep(int bytes_since_last, Address soon_object, |
| int size) { |
| if (!AllocationObserversActive()) { |
| return; |
| } |
| |
| DCHECK(!heap()->allocation_step_in_progress()); |
| heap()->set_allocation_step_in_progress(true); |
| heap()->CreateFillerObjectAt(soon_object, size, ClearRecordedSlots::kNo); |
| for (AllocationObserver* observer : allocation_observers_) { |
| observer->AllocationStep(bytes_since_last, soon_object, size); |
| } |
| heap()->set_allocation_step_in_progress(false); |
| } |
| |
| intptr_t Space::GetNextInlineAllocationStepSize() { |
| intptr_t next_step = 0; |
| for (AllocationObserver* observer : allocation_observers_) { |
| next_step = next_step ? Min(next_step, observer->bytes_to_next_step()) |
| : observer->bytes_to_next_step(); |
| } |
| DCHECK(allocation_observers_.size() == 0 || next_step > 0); |
| return next_step; |
| } |
| |
| PagedSpace::PagedSpace(Heap* heap, AllocationSpace space, |
| Executability executable, FreeList* free_list) |
| : SpaceWithLinearArea(heap, space, free_list), executable_(executable) { |
| area_size_ = MemoryChunkLayout::AllocatableMemoryInMemoryChunk(space); |
| accounting_stats_.Clear(); |
| } |
| |
| void PagedSpace::TearDown() { |
| while (!memory_chunk_list_.Empty()) { |
| MemoryChunk* chunk = memory_chunk_list_.front(); |
| memory_chunk_list_.Remove(chunk); |
| heap()->memory_allocator()->Free<MemoryAllocator::kFull>(chunk); |
| } |
| accounting_stats_.Clear(); |
| } |
| |
| void PagedSpace::RefillFreeList() { |
| // Any PagedSpace might invoke RefillFreeList. We filter all but our old |
| // generation spaces out. |
| if (identity() != OLD_SPACE && identity() != CODE_SPACE && |
| identity() != MAP_SPACE && identity() != RO_SPACE) { |
| return; |
| } |
| DCHECK(!IsDetached()); |
| MarkCompactCollector* collector = heap()->mark_compact_collector(); |
| size_t added = 0; |
| { |
| Page* p = nullptr; |
| while ((p = collector->sweeper()->GetSweptPageSafe(this)) != nullptr) { |
| // We regularly sweep NEVER_ALLOCATE_ON_PAGE pages. We drop the freelist |
| // entries here to make them unavailable for allocations. |
| if (p->IsFlagSet(Page::NEVER_ALLOCATE_ON_PAGE)) { |
| p->ForAllFreeListCategories( |
| [](FreeListCategory* category) { category->Reset(); }); |
| } |
| // Only during compaction pages can actually change ownership. This is |
| // safe because there exists no other competing action on the page links |
| // during compaction. |
| if (is_local()) { |
| DCHECK_NE(this, p->owner()); |
| PagedSpace* owner = reinterpret_cast<PagedSpace*>(p->owner()); |
| base::MutexGuard guard(owner->mutex()); |
| owner->RefineAllocatedBytesAfterSweeping(p); |
| owner->RemovePage(p); |
| added += AddPage(p); |
| } else { |
| base::MutexGuard guard(mutex()); |
| DCHECK_EQ(this, p->owner()); |
| RefineAllocatedBytesAfterSweeping(p); |
| added += RelinkFreeListCategories(p); |
| } |
| added += p->wasted_memory(); |
| if (is_local() && (added > kCompactionMemoryWanted)) break; |
| } |
| } |
| } |
| |
| void PagedSpace::MergeCompactionSpace(CompactionSpace* other) { |
| base::MutexGuard guard(mutex()); |
| |
| DCHECK(identity() == other->identity()); |
| // Unmerged fields: |
| // area_size_ |
| other->FreeLinearAllocationArea(); |
| |
| // The linear allocation area of {other} should be destroyed now. |
| DCHECK_EQ(kNullAddress, other->top()); |
| DCHECK_EQ(kNullAddress, other->limit()); |
| |
| // Move over pages. |
| for (auto it = other->begin(); it != other->end();) { |
| Page* p = *(it++); |
| // Relinking requires the category to be unlinked. |
| other->RemovePage(p); |
| AddPage(p); |
| DCHECK_IMPLIES( |
| !p->IsFlagSet(Page::NEVER_ALLOCATE_ON_PAGE), |
| p->AvailableInFreeList() == p->AvailableInFreeListFromAllocatedBytes()); |
| } |
| DCHECK_EQ(0u, other->Size()); |
| DCHECK_EQ(0u, other->Capacity()); |
| } |
| |
| |
| size_t PagedSpace::CommittedPhysicalMemory() { |
| if (!base::OS::HasLazyCommits()) return CommittedMemory(); |
| MemoryChunk::UpdateHighWaterMark(allocation_info_.top()); |
| size_t size = 0; |
| for (Page* page : *this) { |
| size += page->CommittedPhysicalMemory(); |
| } |
| return size; |
| } |
| |
| bool PagedSpace::ContainsSlow(Address addr) { |
| Page* p = Page::FromAddress(addr); |
| for (Page* page : *this) { |
| if (page == p) return true; |
| } |
| return false; |
| } |
| |
| void PagedSpace::RefineAllocatedBytesAfterSweeping(Page* page) { |
| CHECK(page->SweepingDone()); |
| auto marking_state = |
| heap()->incremental_marking()->non_atomic_marking_state(); |
| // The live_byte on the page was accounted in the space allocated |
| // bytes counter. After sweeping allocated_bytes() contains the |
| // accurate live byte count on the page. |
| size_t old_counter = marking_state->live_bytes(page); |
| size_t new_counter = page->allocated_bytes(); |
| DCHECK_GE(old_counter, new_counter); |
| if (old_counter > new_counter) { |
| DecreaseAllocatedBytes(old_counter - new_counter, page); |
| // Give the heap a chance to adjust counters in response to the |
| // more precise and smaller old generation size. |
| heap()->NotifyRefinedOldGenerationSize(old_counter - new_counter); |
| } |
| marking_state->SetLiveBytes(page, 0); |
| } |
| |
| Page* PagedSpace::RemovePageSafe(int size_in_bytes) { |
| base::MutexGuard guard(mutex()); |
| Page* page = free_list()->GetPageForSize(size_in_bytes); |
| if (!page) return nullptr; |
| RemovePage(page); |
| return page; |
| } |
| |
| size_t PagedSpace::AddPage(Page* page) { |
| CHECK(page->SweepingDone()); |
| page->set_owner(this); |
| memory_chunk_list_.PushBack(page); |
| AccountCommitted(page->size()); |
| IncreaseCapacity(page->area_size()); |
| IncreaseAllocatedBytes(page->allocated_bytes(), page); |
| for (size_t i = 0; i < ExternalBackingStoreType::kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| IncrementExternalBackingStoreBytes(t, page->ExternalBackingStoreBytes(t)); |
| } |
| return RelinkFreeListCategories(page); |
| } |
| |
| void PagedSpace::RemovePage(Page* page) { |
| CHECK(page->SweepingDone()); |
| memory_chunk_list_.Remove(page); |
| UnlinkFreeListCategories(page); |
| DecreaseAllocatedBytes(page->allocated_bytes(), page); |
| DecreaseCapacity(page->area_size()); |
| AccountUncommitted(page->size()); |
| for (size_t i = 0; i < ExternalBackingStoreType::kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| DecrementExternalBackingStoreBytes(t, page->ExternalBackingStoreBytes(t)); |
| } |
| } |
| |
| size_t PagedSpace::ShrinkPageToHighWaterMark(Page* page) { |
| size_t unused = page->ShrinkToHighWaterMark(); |
| accounting_stats_.DecreaseCapacity(static_cast<intptr_t>(unused)); |
| AccountUncommitted(unused); |
| return unused; |
| } |
| |
| void PagedSpace::ResetFreeList() { |
| for (Page* page : *this) { |
| free_list_->EvictFreeListItems(page); |
| } |
| DCHECK(free_list_->IsEmpty()); |
| } |
| |
| void PagedSpace::ShrinkImmortalImmovablePages() { |
| DCHECK(!heap()->deserialization_complete()); |
| MemoryChunk::UpdateHighWaterMark(allocation_info_.top()); |
| FreeLinearAllocationArea(); |
| ResetFreeList(); |
| for (Page* page : *this) { |
| DCHECK(page->IsFlagSet(Page::NEVER_EVACUATE)); |
| ShrinkPageToHighWaterMark(page); |
| } |
| } |
| |
| bool PagedSpace::Expand() { |
| // Always lock against the main space as we can only adjust capacity and |
| // pages concurrently for the main paged space. |
| base::MutexGuard guard(heap()->paged_space(identity())->mutex()); |
| |
| const int size = AreaSize(); |
| |
| if (!heap()->CanExpandOldGeneration(size)) return false; |
| |
| Page* page = |
| heap()->memory_allocator()->AllocatePage(size, this, executable()); |
| if (page == nullptr) return false; |
| // Pages created during bootstrapping may contain immortal immovable objects. |
| if (!heap()->deserialization_complete()) page->MarkNeverEvacuate(); |
| AddPage(page); |
| Free(page->area_start(), page->area_size(), |
| SpaceAccountingMode::kSpaceAccounted); |
| heap()->NotifyOldGenerationExpansion(); |
| return true; |
| } |
| |
| |
| int PagedSpace::CountTotalPages() { |
| int count = 0; |
| for (Page* page : *this) { |
| count++; |
| USE(page); |
| } |
| return count; |
| } |
| |
| void PagedSpace::SetLinearAllocationArea(Address top, Address limit) { |
| SetTopAndLimit(top, limit); |
| if (top != kNullAddress && top != limit && |
| heap()->incremental_marking()->black_allocation()) { |
| Page::FromAllocationAreaAddress(top)->CreateBlackArea(top, limit); |
| } |
| } |
| |
| void PagedSpace::DecreaseLimit(Address new_limit) { |
| Address old_limit = limit(); |
| DCHECK_LE(top(), new_limit); |
| DCHECK_GE(old_limit, new_limit); |
| if (new_limit != old_limit) { |
| SetTopAndLimit(top(), new_limit); |
| Free(new_limit, old_limit - new_limit, |
| SpaceAccountingMode::kSpaceAccounted); |
| if (heap()->incremental_marking()->black_allocation()) { |
| Page::FromAllocationAreaAddress(new_limit)->DestroyBlackArea(new_limit, |
| old_limit); |
| } |
| } |
| } |
| |
| Address SpaceWithLinearArea::ComputeLimit(Address start, Address end, |
| size_t min_size) { |
| DCHECK_GE(end - start, min_size); |
| |
| if (heap()->inline_allocation_disabled()) { |
| // Fit the requested area exactly. |
| return start + min_size; |
| } else if (SupportsInlineAllocation() && AllocationObserversActive()) { |
| // Generated code may allocate inline from the linear allocation area for. |
| // To make sure we can observe these allocations, we use a lower limit. |
| size_t step = GetNextInlineAllocationStepSize(); |
| |
| // TODO(ofrobots): there is subtle difference between old space and new |
| // space here. Any way to avoid it? `step - 1` makes more sense as we would |
| // like to sample the object that straddles the `start + step` boundary. |
| // Rounding down further would introduce a small statistical error in |
| // sampling. However, presently PagedSpace requires limit to be aligned. |
| size_t rounded_step; |
| if (identity() == NEW_SPACE) { |
| DCHECK_GE(step, 1); |
| rounded_step = step - 1; |
| } else { |
| rounded_step = RoundSizeDownToObjectAlignment(static_cast<int>(step)); |
| } |
| return Min(static_cast<Address>(start + min_size + rounded_step), end); |
| } else { |
| // The entire node can be used as the linear allocation area. |
| return end; |
| } |
| } |
| |
| void PagedSpace::MarkLinearAllocationAreaBlack() { |
| DCHECK(heap()->incremental_marking()->black_allocation()); |
| Address current_top = top(); |
| Address current_limit = limit(); |
| if (current_top != kNullAddress && current_top != current_limit) { |
| Page::FromAllocationAreaAddress(current_top) |
| ->CreateBlackArea(current_top, current_limit); |
| } |
| } |
| |
| void PagedSpace::UnmarkLinearAllocationArea() { |
| Address current_top = top(); |
| Address current_limit = limit(); |
| if (current_top != kNullAddress && current_top != current_limit) { |
| Page::FromAllocationAreaAddress(current_top) |
| ->DestroyBlackArea(current_top, current_limit); |
| } |
| } |
| |
| void PagedSpace::FreeLinearAllocationArea() { |
| // Mark the old linear allocation area with a free space map so it can be |
| // skipped when scanning the heap. |
| Address current_top = top(); |
| Address current_limit = limit(); |
| if (current_top == kNullAddress) { |
| DCHECK_EQ(kNullAddress, current_limit); |
| return; |
| } |
| |
| if (heap()->incremental_marking()->black_allocation()) { |
| Page* page = Page::FromAllocationAreaAddress(current_top); |
| |
| // Clear the bits in the unused black area. |
| if (current_top != current_limit) { |
| IncrementalMarking::MarkingState* marking_state = |
| heap()->incremental_marking()->marking_state(); |
| marking_state->bitmap(page)->ClearRange( |
| page->AddressToMarkbitIndex(current_top), |
| page->AddressToMarkbitIndex(current_limit)); |
| marking_state->IncrementLiveBytes( |
| page, -static_cast<int>(current_limit - current_top)); |
| } |
| } |
| |
| InlineAllocationStep(current_top, kNullAddress, kNullAddress, 0); |
| SetTopAndLimit(kNullAddress, kNullAddress); |
| DCHECK_GE(current_limit, current_top); |
| |
| // The code page of the linear allocation area needs to be unprotected |
| // because we are going to write a filler into that memory area below. |
| if (identity() == CODE_SPACE) { |
| heap()->UnprotectAndRegisterMemoryChunk( |
| MemoryChunk::FromAddress(current_top)); |
| } |
| Free(current_top, current_limit - current_top, |
| SpaceAccountingMode::kSpaceAccounted); |
| } |
| |
| void PagedSpace::ReleasePage(Page* page) { |
| DCHECK_EQ( |
| 0, heap()->incremental_marking()->non_atomic_marking_state()->live_bytes( |
| page)); |
| DCHECK_EQ(page->owner(), this); |
| |
| free_list_->EvictFreeListItems(page); |
| DCHECK(!free_list_->ContainsPageFreeListItems(page)); |
| |
| if (Page::FromAllocationAreaAddress(allocation_info_.top()) == page) { |
| DCHECK(!top_on_previous_step_); |
| allocation_info_.Reset(kNullAddress, kNullAddress); |
| } |
| |
| AccountUncommitted(page->size()); |
| accounting_stats_.DecreaseCapacity(page->area_size()); |
| heap()->memory_allocator()->Free<MemoryAllocator::kPreFreeAndQueue>(page); |
| } |
| |
| void PagedSpace::SetReadable() { |
| DCHECK(identity() == CODE_SPACE); |
| for (Page* page : *this) { |
| CHECK(heap()->memory_allocator()->IsMemoryChunkExecutable(page)); |
| page->SetReadable(); |
| } |
| } |
| |
| void PagedSpace::SetReadAndExecutable() { |
| DCHECK(identity() == CODE_SPACE); |
| for (Page* page : *this) { |
| CHECK(heap()->memory_allocator()->IsMemoryChunkExecutable(page)); |
| page->SetReadAndExecutable(); |
| } |
| } |
| |
| void PagedSpace::SetReadAndWritable() { |
| DCHECK(identity() == CODE_SPACE); |
| for (Page* page : *this) { |
| CHECK(heap()->memory_allocator()->IsMemoryChunkExecutable(page)); |
| page->SetReadAndWritable(); |
| } |
| } |
| |
| std::unique_ptr<ObjectIterator> PagedSpace::GetObjectIterator() { |
| return std::unique_ptr<ObjectIterator>(new PagedSpaceObjectIterator(this)); |
| } |
| |
| bool PagedSpace::RefillLinearAllocationAreaFromFreeList(size_t size_in_bytes) { |
| DCHECK(IsAligned(size_in_bytes, kTaggedSize)); |
| DCHECK_LE(top(), limit()); |
| #ifdef DEBUG |
| if (top() != limit()) { |
| DCHECK_EQ(Page::FromAddress(top()), Page::FromAddress(limit() - 1)); |
| } |
| #endif |
| // Don't free list allocate if there is linear space available. |
| DCHECK_LT(static_cast<size_t>(limit() - top()), size_in_bytes); |
| |
| // Mark the old linear allocation area with a free space map so it can be |
| // skipped when scanning the heap. This also puts it back in the free list |
| // if it is big enough. |
| FreeLinearAllocationArea(); |
| |
| if (!is_local()) { |
| heap()->StartIncrementalMarkingIfAllocationLimitIsReached( |
| heap()->GCFlagsForIncrementalMarking(), |
| kGCCallbackScheduleIdleGarbageCollection); |
| } |
| |
| size_t new_node_size = 0; |
| FreeSpace new_node = free_list_->Allocate(size_in_bytes, &new_node_size); |
| if (new_node.is_null()) return false; |
| |
| DCHECK_GE(new_node_size, size_in_bytes); |
| |
| // The old-space-step might have finished sweeping and restarted marking. |
| // Verify that it did not turn the page of the new node into an evacuation |
| // candidate. |
| DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_node)); |
| |
| // Memory in the linear allocation area is counted as allocated. We may free |
| // a little of this again immediately - see below. |
| Page* page = Page::FromHeapObject(new_node); |
| IncreaseAllocatedBytes(new_node_size, page); |
| |
| Address start = new_node.address(); |
| Address end = new_node.address() + new_node_size; |
| Address limit = ComputeLimit(start, end, size_in_bytes); |
| DCHECK_LE(limit, end); |
| DCHECK_LE(size_in_bytes, limit - start); |
| if (limit != end) { |
| if (identity() == CODE_SPACE) { |
| heap()->UnprotectAndRegisterMemoryChunk(page); |
| } |
| Free(limit, end - limit, SpaceAccountingMode::kSpaceAccounted); |
| } |
| SetLinearAllocationArea(start, limit); |
| |
| return true; |
| } |
| |
| #ifdef DEBUG |
| void PagedSpace::Print() {} |
| #endif |
| |
| #ifdef VERIFY_HEAP |
| void PagedSpace::Verify(Isolate* isolate, ObjectVisitor* visitor) { |
| bool allocation_pointer_found_in_space = |
| (allocation_info_.top() == allocation_info_.limit()); |
| size_t external_space_bytes[kNumTypes]; |
| size_t external_page_bytes[kNumTypes]; |
| |
| for (int i = 0; i < kNumTypes; i++) { |
| external_space_bytes[static_cast<ExternalBackingStoreType>(i)] = 0; |
| } |
| |
| for (Page* page : *this) { |
| CHECK(page->owner() == this); |
| |
| for (int i = 0; i < kNumTypes; i++) { |
| external_page_bytes[static_cast<ExternalBackingStoreType>(i)] = 0; |
| } |
| |
| if (page == Page::FromAllocationAreaAddress(allocation_info_.top())) { |
| allocation_pointer_found_in_space = true; |
| } |
| CHECK(page->SweepingDone()); |
| PagedSpaceObjectIterator it(page); |
| Address end_of_previous_object = page->area_start(); |
| Address top = page->area_end(); |
| |
| for (HeapObject object = it.Next(); !object.is_null(); object = it.Next()) { |
| CHECK(end_of_previous_object <= object.address()); |
| |
| // The first word should be a map, and we expect all map pointers to |
| // be in map space. |
| Map map = object.map(); |
| CHECK(map.IsMap()); |
| CHECK(ReadOnlyHeap::Contains(map) || |
| isolate->heap()->map_space()->Contains(map)); |
| |
| // Perform space-specific object verification. |
| VerifyObject(object); |
| |
| // The object itself should look OK. |
| object.ObjectVerify(isolate); |
| |
| if (!FLAG_verify_heap_skip_remembered_set) { |
| isolate->heap()->VerifyRememberedSetFor(object); |
| } |
| |
| // All the interior pointers should be contained in the heap. |
| int size = object.Size(); |
| object.IterateBody(map, size, visitor); |
| CHECK(object.address() + size <= top); |
| end_of_previous_object = object.address() + size; |
| |
| if (object.IsExternalString()) { |
| ExternalString external_string = ExternalString::cast(object); |
| size_t size = external_string.ExternalPayloadSize(); |
| external_page_bytes[ExternalBackingStoreType::kExternalString] += size; |
| } else if (object.IsJSArrayBuffer()) { |
| JSArrayBuffer array_buffer = JSArrayBuffer::cast(object); |
| if (ArrayBufferTracker::IsTracked(array_buffer)) { |
| size_t size = array_buffer.byte_length(); |
| external_page_bytes[ExternalBackingStoreType::kArrayBuffer] += size; |
| } |
| } |
| } |
| for (int i = 0; i < kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| CHECK_EQ(external_page_bytes[t], page->ExternalBackingStoreBytes(t)); |
| external_space_bytes[t] += external_page_bytes[t]; |
| } |
| } |
| for (int i = 0; i < kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| CHECK_EQ(external_space_bytes[t], ExternalBackingStoreBytes(t)); |
| } |
| CHECK(allocation_pointer_found_in_space); |
| #ifdef DEBUG |
| VerifyCountersAfterSweeping(); |
| #endif |
| } |
| |
| void PagedSpace::VerifyLiveBytes() { |
| IncrementalMarking::MarkingState* marking_state = |
| heap()->incremental_marking()->marking_state(); |
| for (Page* page : *this) { |
| CHECK(page->SweepingDone()); |
| PagedSpaceObjectIterator it(page); |
| int black_size = 0; |
| for (HeapObject object = it.Next(); !object.is_null(); object = it.Next()) { |
| // All the interior pointers should be contained in the heap. |
| if (marking_state->IsBlack(object)) { |
| black_size += object.Size(); |
| } |
| } |
| CHECK_LE(black_size, marking_state->live_bytes(page)); |
| } |
| } |
| #endif // VERIFY_HEAP |
| |
| #ifdef DEBUG |
| void PagedSpace::VerifyCountersAfterSweeping() { |
| size_t total_capacity = 0; |
| size_t total_allocated = 0; |
| for (Page* page : *this) { |
| DCHECK(page->SweepingDone()); |
| total_capacity += page->area_size(); |
| PagedSpaceObjectIterator it(page); |
| size_t real_allocated = 0; |
| for (HeapObject object = it.Next(); !object.is_null(); object = it.Next()) { |
| if (!object.IsFiller()) { |
| real_allocated += object.Size(); |
| } |
| } |
| total_allocated += page->allocated_bytes(); |
| // The real size can be smaller than the accounted size if array trimming, |
| // object slack tracking happened after sweeping. |
| DCHECK_LE(real_allocated, accounting_stats_.AllocatedOnPage(page)); |
| DCHECK_EQ(page->allocated_bytes(), accounting_stats_.AllocatedOnPage(page)); |
| } |
| DCHECK_EQ(total_capacity, accounting_stats_.Capacity()); |
| DCHECK_EQ(total_allocated, accounting_stats_.Size()); |
| } |
| |
| void PagedSpace::VerifyCountersBeforeConcurrentSweeping() { |
| // We need to refine the counters on pages that are already swept and have |
| // not been moved over to the actual space. Otherwise, the AccountingStats |
| // are just an over approximation. |
| RefillFreeList(); |
| |
| size_t total_capacity = 0; |
| size_t total_allocated = 0; |
| auto marking_state = |
| heap()->incremental_marking()->non_atomic_marking_state(); |
| for (Page* page : *this) { |
| size_t page_allocated = |
| page->SweepingDone() |
| ? page->allocated_bytes() |
| : static_cast<size_t>(marking_state->live_bytes(page)); |
| total_capacity += page->area_size(); |
| total_allocated += page_allocated; |
| DCHECK_EQ(page_allocated, accounting_stats_.AllocatedOnPage(page)); |
| } |
| DCHECK_EQ(total_capacity, accounting_stats_.Capacity()); |
| DCHECK_EQ(total_allocated, accounting_stats_.Size()); |
| } |
| #endif |
| |
| // ----------------------------------------------------------------------------- |
| // NewSpace implementation |
| |
| NewSpace::NewSpace(Heap* heap, v8::PageAllocator* page_allocator, |
| size_t initial_semispace_capacity, |
| size_t max_semispace_capacity) |
| : SpaceWithLinearArea(heap, NEW_SPACE, new NoFreeList()), |
| to_space_(heap, kToSpace), |
| from_space_(heap, kFromSpace) { |
| DCHECK(initial_semispace_capacity <= max_semispace_capacity); |
| DCHECK( |
| base::bits::IsPowerOfTwo(static_cast<uint32_t>(max_semispace_capacity))); |
| |
| to_space_.SetUp(initial_semispace_capacity, max_semispace_capacity); |
| from_space_.SetUp(initial_semispace_capacity, max_semispace_capacity); |
| if (!to_space_.Commit()) { |
| V8::FatalProcessOutOfMemory(heap->isolate(), "New space setup"); |
| } |
| DCHECK(!from_space_.is_committed()); // No need to use memory yet. |
| ResetLinearAllocationArea(); |
| } |
| |
| void NewSpace::TearDown() { |
| allocation_info_.Reset(kNullAddress, kNullAddress); |
| |
| to_space_.TearDown(); |
| from_space_.TearDown(); |
| } |
| |
| void NewSpace::Flip() { SemiSpace::Swap(&from_space_, &to_space_); } |
| |
| |
| void NewSpace::Grow() { |
| // Double the semispace size but only up to maximum capacity. |
| DCHECK(TotalCapacity() < MaximumCapacity()); |
| size_t new_capacity = |
| Min(MaximumCapacity(), |
| static_cast<size_t>(FLAG_semi_space_growth_factor) * TotalCapacity()); |
| if (to_space_.GrowTo(new_capacity)) { |
| // Only grow from space if we managed to grow to-space. |
| if (!from_space_.GrowTo(new_capacity)) { |
| // If we managed to grow to-space but couldn't grow from-space, |
| // attempt to shrink to-space. |
| if (!to_space_.ShrinkTo(from_space_.current_capacity())) { |
| // We are in an inconsistent state because we could not |
| // commit/uncommit memory from new space. |
| FATAL("inconsistent state"); |
| } |
| } |
| } |
| DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); |
| } |
| |
| |
| void NewSpace::Shrink() { |
| size_t new_capacity = Max(InitialTotalCapacity(), 2 * Size()); |
| size_t rounded_new_capacity = ::RoundUp(new_capacity, Page::kPageSize); |
| if (rounded_new_capacity < TotalCapacity() && |
| to_space_.ShrinkTo(rounded_new_capacity)) { |
| // Only shrink from-space if we managed to shrink to-space. |
| from_space_.Reset(); |
| 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_.current_capacity())) { |
| // We are in an inconsistent state because we could not |
| // commit/uncommit memory from new space. |
| FATAL("inconsistent state"); |
| } |
| } |
| } |
| DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); |
| } |
| |
| bool NewSpace::Rebalance() { |
| // Order here is important to make use of the page pool. |
| return to_space_.EnsureCurrentCapacity() && |
| from_space_.EnsureCurrentCapacity(); |
| } |
| |
| bool SemiSpace::EnsureCurrentCapacity() { |
| if (is_committed()) { |
| const int expected_pages = |
| static_cast<int>(current_capacity_ / Page::kPageSize); |
| MemoryChunk* current_page = first_page(); |
| int actual_pages = 0; |
| |
| // First iterate through the pages list until expected pages if so many |
| // pages exist. |
| while (current_page != nullptr && actual_pages < expected_pages) { |
| actual_pages++; |
| current_page = current_page->list_node().next(); |
| } |
| |
| // Free all overallocated pages which are behind current_page. |
| while (current_page) { |
| MemoryChunk* next_current = current_page->list_node().next(); |
| memory_chunk_list_.Remove(current_page); |
| // Clear new space flags to avoid this page being treated as a new |
| // space page that is potentially being swept. |
| current_page->SetFlags(0, Page::kIsInYoungGenerationMask); |
| heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>( |
| current_page); |
| current_page = next_current; |
| } |
| |
| // Add more pages if we have less than expected_pages. |
| IncrementalMarking::NonAtomicMarkingState* marking_state = |
| heap()->incremental_marking()->non_atomic_marking_state(); |
| while (actual_pages < expected_pages) { |
| actual_pages++; |
| current_page = |
| heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>( |
| MemoryChunkLayout::AllocatableMemoryInDataPage(), this, |
| NOT_EXECUTABLE); |
| if (current_page == nullptr) return false; |
| DCHECK_NOT_NULL(current_page); |
| memory_chunk_list_.PushBack(current_page); |
| marking_state->ClearLiveness(current_page); |
| current_page->SetFlags(first_page()->GetFlags(), |
| static_cast<uintptr_t>(Page::kCopyAllFlags)); |
| heap()->CreateFillerObjectAt(current_page->area_start(), |
| static_cast<int>(current_page->area_size()), |
| ClearRecordedSlots::kNo); |
| } |
| } |
| return true; |
| } |
| |
| LinearAllocationArea LocalAllocationBuffer::Close() { |
| if (IsValid()) { |
| heap_->CreateFillerObjectAt( |
| allocation_info_.top(), |
| static_cast<int>(allocation_info_.limit() - allocation_info_.top()), |
| ClearRecordedSlots::kNo); |
| const LinearAllocationArea old_info = allocation_info_; |
| allocation_info_ = LinearAllocationArea(kNullAddress, kNullAddress); |
| return old_info; |
| } |
| return LinearAllocationArea(kNullAddress, kNullAddress); |
| } |
| |
| LocalAllocationBuffer::LocalAllocationBuffer( |
| Heap* heap, LinearAllocationArea allocation_info) V8_NOEXCEPT |
| : heap_(heap), |
| allocation_info_(allocation_info) { |
| if (IsValid()) { |
| heap_->CreateFillerObjectAt( |
| allocation_info_.top(), |
| static_cast<int>(allocation_info_.limit() - allocation_info_.top()), |
| ClearRecordedSlots::kNo); |
| } |
| } |
| |
| LocalAllocationBuffer::LocalAllocationBuffer(const LocalAllocationBuffer& other) |
| V8_NOEXCEPT { |
| *this = other; |
| } |
| |
| LocalAllocationBuffer& LocalAllocationBuffer::operator=( |
| const LocalAllocationBuffer& other) V8_NOEXCEPT { |
| Close(); |
| heap_ = other.heap_; |
| allocation_info_ = other.allocation_info_; |
| |
| // This is needed since we (a) cannot yet use move-semantics, and (b) want |
| // to make the use of the class easy by it as value and (c) implicitly call |
| // {Close} upon copy. |
| const_cast<LocalAllocationBuffer&>(other).allocation_info_.Reset( |
| kNullAddress, kNullAddress); |
| return *this; |
| } |
| |
| void NewSpace::UpdateLinearAllocationArea() { |
| // Make sure there is no unaccounted allocations. |
| DCHECK(!AllocationObserversActive() || top_on_previous_step_ == top()); |
| |
| Address new_top = to_space_.page_low(); |
| MemoryChunk::UpdateHighWaterMark(allocation_info_.top()); |
| allocation_info_.Reset(new_top, to_space_.page_high()); |
| // The order of the following two stores is important. |
| // See the corresponding loads in ConcurrentMarking::Run. |
| original_limit_.store(limit(), std::memory_order_relaxed); |
| original_top_.store(top(), std::memory_order_release); |
| StartNextInlineAllocationStep(); |
| DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); |
| } |
| |
| void NewSpace::ResetLinearAllocationArea() { |
| // Do a step to account for memory allocated so far before resetting. |
| InlineAllocationStep(top(), top(), kNullAddress, 0); |
| to_space_.Reset(); |
| UpdateLinearAllocationArea(); |
| // Clear all mark-bits in the to-space. |
| IncrementalMarking::NonAtomicMarkingState* marking_state = |
| heap()->incremental_marking()->non_atomic_marking_state(); |
| for (Page* p : to_space_) { |
| marking_state->ClearLiveness(p); |
| // Concurrent marking may have local live bytes for this page. |
| heap()->concurrent_marking()->ClearMemoryChunkData(p); |
| } |
| } |
| |
| void NewSpace::UpdateInlineAllocationLimit(size_t min_size) { |
| Address new_limit = ComputeLimit(top(), to_space_.page_high(), min_size); |
| allocation_info_.set_limit(new_limit); |
| DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); |
| } |
| |
| void PagedSpace::UpdateInlineAllocationLimit(size_t min_size) { |
| Address new_limit = ComputeLimit(top(), limit(), min_size); |
| DCHECK_LE(new_limit, limit()); |
| DecreaseLimit(new_limit); |
| } |
| |
| bool NewSpace::AddFreshPage() { |
| Address top = allocation_info_.top(); |
| DCHECK(!OldSpace::IsAtPageStart(top)); |
| |
| // Do a step to account for memory allocated on previous page. |
| InlineAllocationStep(top, top, kNullAddress, 0); |
| |
| if (!to_space_.AdvancePage()) { |
| // No more pages left to advance. |
| return false; |
| } |
| |
| // Clear remainder of current page. |
| Address limit = Page::FromAllocationAreaAddress(top)->area_end(); |
| int remaining_in_page = static_cast<int>(limit - top); |
| heap()->CreateFillerObjectAt(top, remaining_in_page, ClearRecordedSlots::kNo); |
| UpdateLinearAllocationArea(); |
| |
| return true; |
| } |
| |
| |
| bool NewSpace::AddFreshPageSynchronized() { |
| base::MutexGuard guard(&mutex_); |
| return AddFreshPage(); |
| } |
| |
| |
| bool NewSpace::EnsureAllocation(int size_in_bytes, |
| AllocationAlignment alignment) { |
| Address old_top = allocation_info_.top(); |
| Address high = to_space_.page_high(); |
| int filler_size = Heap::GetFillToAlign(old_top, alignment); |
| int aligned_size_in_bytes = size_in_bytes + filler_size; |
| |
| if (old_top + aligned_size_in_bytes > high) { |
| // Not enough room in the page, try to allocate a new one. |
| if (!AddFreshPage()) { |
| return false; |
| } |
| |
| old_top = allocation_info_.top(); |
| high = to_space_.page_high(); |
| filler_size = Heap::GetFillToAlign(old_top, alignment); |
| } |
| |
| DCHECK(old_top + aligned_size_in_bytes <= high); |
| |
| if (allocation_info_.limit() < high) { |
| // Either the limit has been lowered because linear allocation was disabled |
| // or because incremental marking wants to get a chance to do a step, |
| // or because idle scavenge job wants to get a chance to post a task. |
| // Set the new limit accordingly. |
| Address new_top = old_top + aligned_size_in_bytes; |
| Address soon_object = old_top + filler_size; |
| InlineAllocationStep(new_top, new_top, soon_object, size_in_bytes); |
| UpdateInlineAllocationLimit(aligned_size_in_bytes); |
| } |
| return true; |
| } |
| |
| size_t LargeObjectSpace::Available() { |
| // We return zero here since we cannot take advantage of already allocated |
| // large object memory. |
| return 0; |
| } |
| |
| void SpaceWithLinearArea::StartNextInlineAllocationStep() { |
| if (heap()->allocation_step_in_progress()) { |
| // If we are mid-way through an existing step, don't start a new one. |
| return; |
| } |
| |
| if (AllocationObserversActive()) { |
| top_on_previous_step_ = top(); |
| UpdateInlineAllocationLimit(0); |
| } else { |
| DCHECK_EQ(kNullAddress, top_on_previous_step_); |
| } |
| } |
| |
| void SpaceWithLinearArea::AddAllocationObserver(AllocationObserver* observer) { |
| InlineAllocationStep(top(), top(), kNullAddress, 0); |
| Space::AddAllocationObserver(observer); |
| DCHECK_IMPLIES(top_on_previous_step_, AllocationObserversActive()); |
| } |
| |
| void SpaceWithLinearArea::RemoveAllocationObserver( |
| AllocationObserver* observer) { |
| Address top_for_next_step = |
| allocation_observers_.size() == 1 ? kNullAddress : top(); |
| InlineAllocationStep(top(), top_for_next_step, kNullAddress, 0); |
| Space::RemoveAllocationObserver(observer); |
| DCHECK_IMPLIES(top_on_previous_step_, AllocationObserversActive()); |
| } |
| |
| void SpaceWithLinearArea::PauseAllocationObservers() { |
| // Do a step to account for memory allocated so far. |
| InlineAllocationStep(top(), kNullAddress, kNullAddress, 0); |
| Space::PauseAllocationObservers(); |
| DCHECK_EQ(kNullAddress, top_on_previous_step_); |
| UpdateInlineAllocationLimit(0); |
| } |
| |
| void SpaceWithLinearArea::ResumeAllocationObservers() { |
| DCHECK_EQ(kNullAddress, top_on_previous_step_); |
| Space::ResumeAllocationObservers(); |
| StartNextInlineAllocationStep(); |
| } |
| |
| void SpaceWithLinearArea::InlineAllocationStep(Address top, |
| Address top_for_next_step, |
| Address soon_object, |
| size_t size) { |
| if (heap()->allocation_step_in_progress()) { |
| // Avoid starting a new step if we are mid-way through an existing one. |
| return; |
| } |
| |
| if (top_on_previous_step_) { |
| if (top < top_on_previous_step_) { |
| // Generated code decreased the top pointer to do folded allocations. |
| DCHECK_NE(top, kNullAddress); |
| DCHECK_EQ(Page::FromAllocationAreaAddress(top), |
| Page::FromAllocationAreaAddress(top_on_previous_step_)); |
| top_on_previous_step_ = top; |
| } |
| int bytes_allocated = static_cast<int>(top - top_on_previous_step_); |
| AllocationStep(bytes_allocated, soon_object, static_cast<int>(size)); |
| top_on_previous_step_ = top_for_next_step; |
| } |
| } |
| |
| std::unique_ptr<ObjectIterator> NewSpace::GetObjectIterator() { |
| return std::unique_ptr<ObjectIterator>(new SemiSpaceObjectIterator(this)); |
| } |
| |
| #ifdef VERIFY_HEAP |
| // We do not use the SemiSpaceObjectIterator because verification doesn't assume |
| // that it works (it depends on the invariants we are checking). |
| void NewSpace::Verify(Isolate* isolate) { |
| // The allocation pointer should be in the space or at the very end. |
| DCHECK_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_.first_page()->area_start(); |
| CHECK_EQ(current, to_space_.space_start()); |
| |
| size_t external_space_bytes[kNumTypes]; |
| for (int i = 0; i < kNumTypes; i++) { |
| external_space_bytes[static_cast<ExternalBackingStoreType>(i)] = 0; |
| } |
| |
| while (current != top()) { |
| if (!Page::IsAlignedToPageSize(current)) { |
| // The allocation pointer should not be in the middle of an object. |
| CHECK(!Page::FromAllocationAreaAddress(current)->ContainsLimit(top()) || |
| 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 or read-only space. |
| Map map = object.map(); |
| CHECK(map.IsMap()); |
| CHECK(ReadOnlyHeap::Contains(map) || heap()->map_space()->Contains(map)); |
| |
| // The object should not be code or a map. |
| CHECK(!object.IsMap()); |
| CHECK(!object.IsAbstractCode()); |
| |
| // The object itself should look OK. |
| object.ObjectVerify(isolate); |
| |
| // All the interior pointers should be contained in the heap. |
| VerifyPointersVisitor visitor(heap()); |
| int size = object.Size(); |
| object.IterateBody(map, size, &visitor); |
| |
| if (object.IsExternalString()) { |
| ExternalString external_string = ExternalString::cast(object); |
| size_t size = external_string.ExternalPayloadSize(); |
| external_space_bytes[ExternalBackingStoreType::kExternalString] += size; |
| } else if (object.IsJSArrayBuffer()) { |
| JSArrayBuffer array_buffer = JSArrayBuffer::cast(object); |
| if (ArrayBufferTracker::IsTracked(array_buffer)) { |
| size_t size = array_buffer.byte_length(); |
| external_space_bytes[ExternalBackingStoreType::kArrayBuffer] += size; |
| } |
| } |
| |
| current += size; |
| } else { |
| // At end of page, switch to next page. |
| Page* page = Page::FromAllocationAreaAddress(current)->next_page(); |
| current = page->area_start(); |
| } |
| } |
| |
| for (int i = 0; i < kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| CHECK_EQ(external_space_bytes[t], ExternalBackingStoreBytes(t)); |
| } |
| |
| // Check semi-spaces. |
| CHECK_EQ(from_space_.id(), kFromSpace); |
| CHECK_EQ(to_space_.id(), kToSpace); |
| from_space_.Verify(); |
| to_space_.Verify(); |
| } |
| #endif |
| |
| // ----------------------------------------------------------------------------- |
| // SemiSpace implementation |
| |
| void SemiSpace::SetUp(size_t initial_capacity, size_t maximum_capacity) { |
| DCHECK_GE(maximum_capacity, static_cast<size_t>(Page::kPageSize)); |
| minimum_capacity_ = RoundDown(initial_capacity, Page::kPageSize); |
| current_capacity_ = minimum_capacity_; |
| maximum_capacity_ = RoundDown(maximum_capacity, Page::kPageSize); |
| committed_ = false; |
| } |
| |
| |
| void SemiSpace::TearDown() { |
| // Properly uncommit memory to keep the allocator counters in sync. |
| if (is_committed()) { |
| Uncommit(); |
| } |
| current_capacity_ = maximum_capacity_ = 0; |
| } |
| |
| |
| bool SemiSpace::Commit() { |
| DCHECK(!is_committed()); |
| const int num_pages = static_cast<int>(current_capacity_ / Page::kPageSize); |
| for (int pages_added = 0; pages_added < num_pages; pages_added++) { |
| // Pages in the new spaces can be moved to the old space by the full |
| // collector. Therefore, they must be initialized with the same FreeList as |
| // old pages. |
| Page* new_page = |
| heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>( |
| MemoryChunkLayout::AllocatableMemoryInDataPage(), this, |
| NOT_EXECUTABLE); |
| if (new_page == nullptr) { |
| if (pages_added) RewindPages(pages_added); |
| return false; |
| } |
| memory_chunk_list_.PushBack(new_page); |
| } |
| Reset(); |
| AccountCommitted(current_capacity_); |
| if (age_mark_ == kNullAddress) { |
| age_mark_ = first_page()->area_start(); |
| } |
| committed_ = true; |
| return true; |
| } |
| |
| |
| bool SemiSpace::Uncommit() { |
| DCHECK(is_committed()); |
| while (!memory_chunk_list_.Empty()) { |
| MemoryChunk* chunk = memory_chunk_list_.front(); |
| memory_chunk_list_.Remove(chunk); |
| heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(chunk); |
| } |
| current_page_ = nullptr; |
| AccountUncommitted(current_capacity_); |
| committed_ = false; |
| heap()->memory_allocator()->unmapper()->FreeQueuedChunks(); |
| return true; |
| } |
| |
| |
| size_t SemiSpace::CommittedPhysicalMemory() { |
| if (!is_committed()) return 0; |
| size_t size = 0; |
| for (Page* p : *this) { |
| size += p->CommittedPhysicalMemory(); |
| } |
| return size; |
| } |
| |
| bool SemiSpace::GrowTo(size_t new_capacity) { |
| if (!is_committed()) { |
| if (!Commit()) return false; |
| } |
| DCHECK_EQ(new_capacity & kPageAlignmentMask, 0u); |
| DCHECK_LE(new_capacity, maximum_capacity_); |
| DCHECK_GT(new_capacity, current_capacity_); |
| const size_t delta = new_capacity - current_capacity_; |
| DCHECK(IsAligned(delta, AllocatePageSize())); |
| const int delta_pages = static_cast<int>(delta / Page::kPageSize); |
| DCHECK(last_page()); |
| IncrementalMarking::NonAtomicMarkingState* marking_state = |
| heap()->incremental_marking()->non_atomic_marking_state(); |
| for (int pages_added = 0; pages_added < delta_pages; pages_added++) { |
| Page* new_page = |
| heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>( |
| MemoryChunkLayout::AllocatableMemoryInDataPage(), this, |
| NOT_EXECUTABLE); |
| if (new_page == nullptr) { |
| if (pages_added) RewindPages(pages_added); |
| return false; |
| } |
| memory_chunk_list_.PushBack(new_page); |
| marking_state->ClearLiveness(new_page); |
| // Duplicate the flags that was set on the old page. |
| new_page->SetFlags(last_page()->GetFlags(), Page::kCopyOnFlipFlagsMask); |
| } |
| AccountCommitted(delta); |
| current_capacity_ = new_capacity; |
| return true; |
| } |
| |
| void SemiSpace::RewindPages(int num_pages) { |
| DCHECK_GT(num_pages, 0); |
| DCHECK(last_page()); |
| while (num_pages > 0) { |
| MemoryChunk* last = last_page(); |
| memory_chunk_list_.Remove(last); |
| heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(last); |
| num_pages--; |
| } |
| } |
| |
| bool SemiSpace::ShrinkTo(size_t new_capacity) { |
| DCHECK_EQ(new_capacity & kPageAlignmentMask, 0u); |
| DCHECK_GE(new_capacity, minimum_capacity_); |
| DCHECK_LT(new_capacity, current_capacity_); |
| if (is_committed()) { |
| const size_t delta = current_capacity_ - new_capacity; |
| DCHECK(IsAligned(delta, Page::kPageSize)); |
| int delta_pages = static_cast<int>(delta / Page::kPageSize); |
| RewindPages(delta_pages); |
| AccountUncommitted(delta); |
| heap()->memory_allocator()->unmapper()->FreeQueuedChunks(); |
| } |
| current_capacity_ = new_capacity; |
| return true; |
| } |
| |
| void SemiSpace::FixPagesFlags(intptr_t flags, intptr_t mask) { |
| for (Page* page : *this) { |
| page->set_owner(this); |
| page->SetFlags(flags, mask); |
| if (id_ == kToSpace) { |
| page->ClearFlag(MemoryChunk::FROM_PAGE); |
| page->SetFlag(MemoryChunk::TO_PAGE); |
| page->ClearFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK); |
| heap()->incremental_marking()->non_atomic_marking_state()->SetLiveBytes( |
| page, 0); |
| } else { |
| page->SetFlag(MemoryChunk::FROM_PAGE); |
| page->ClearFlag(MemoryChunk::TO_PAGE); |
| } |
| DCHECK(page->InYoungGeneration()); |
| } |
| } |
| |
| |
| void SemiSpace::Reset() { |
| DCHECK(first_page()); |
| DCHECK(last_page()); |
| current_page_ = first_page(); |
| pages_used_ = 0; |
| } |
| |
| void SemiSpace::RemovePage(Page* page) { |
| if (current_page_ == page) { |
| if (page->prev_page()) { |
| current_page_ = page->prev_page(); |
| } |
| } |
| memory_chunk_list_.Remove(page); |
| for (size_t i = 0; i < ExternalBackingStoreType::kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| DecrementExternalBackingStoreBytes(t, page->ExternalBackingStoreBytes(t)); |
| } |
| } |
| |
| void SemiSpace::PrependPage(Page* page) { |
| page->SetFlags(current_page()->GetFlags(), |
| static_cast<uintptr_t>(Page::kCopyAllFlags)); |
| page->set_owner(this); |
| memory_chunk_list_.PushFront(page); |
| pages_used_++; |
| for (size_t i = 0; i < ExternalBackingStoreType::kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| IncrementExternalBackingStoreBytes(t, page->ExternalBackingStoreBytes(t)); |
| } |
| } |
| |
| void SemiSpace::Swap(SemiSpace* from, SemiSpace* to) { |
| // We won't be swapping semispaces without data in them. |
| DCHECK(from->first_page()); |
| DCHECK(to->first_page()); |
| |
| intptr_t saved_to_space_flags = to->current_page()->GetFlags(); |
| |
| // We swap all properties but id_. |
| std::swap(from->current_capacity_, to->current_capacity_); |
| std::swap(from->maximum_capacity_, to->maximum_capacity_); |
| std::swap(from->minimum_capacity_, to->minimum_capacity_); |
| std::swap(from->age_mark_, to->age_mark_); |
| std::swap(from->committed_, to->committed_); |
| std::swap(from->memory_chunk_list_, to->memory_chunk_list_); |
| std::swap(from->current_page_, to->current_page_); |
| std::swap(from->external_backing_store_bytes_, |
| to->external_backing_store_bytes_); |
| |
| to->FixPagesFlags(saved_to_space_flags, Page::kCopyOnFlipFlagsMask); |
| from->FixPagesFlags(0, 0); |
| } |
| |
| void SemiSpace::set_age_mark(Address mark) { |
| DCHECK_EQ(Page::FromAllocationAreaAddress(mark)->owner(), this); |
| age_mark_ = mark; |
| // Mark all pages up to the one containing mark. |
| for (Page* p : PageRange(space_start(), mark)) { |
| p->SetFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK); |
| } |
| } |
| |
| std::unique_ptr<ObjectIterator> SemiSpace::GetObjectIterator() { |
| // Use the NewSpace::NewObjectIterator to iterate the ToSpace. |
| UNREACHABLE(); |
| } |
| |
| #ifdef DEBUG |
| void SemiSpace::Print() {} |
| #endif |
| |
| #ifdef VERIFY_HEAP |
| void SemiSpace::Verify() { |
| bool is_from_space = (id_ == kFromSpace); |
| size_t external_backing_store_bytes[kNumTypes]; |
| |
| for (int i = 0; i < kNumTypes; i++) { |
| external_backing_store_bytes[static_cast<ExternalBackingStoreType>(i)] = 0; |
| } |
| |
| for (Page* page : *this) { |
| CHECK_EQ(page->owner(), this); |
| CHECK(page->InNewSpace()); |
| CHECK(page->IsFlagSet(is_from_space ? MemoryChunk::FROM_PAGE |
| : MemoryChunk::TO_PAGE)); |
| CHECK(!page->IsFlagSet(is_from_space ? MemoryChunk::TO_PAGE |
| : MemoryChunk::FROM_PAGE)); |
| CHECK(page->IsFlagSet(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING)); |
| if (!is_from_space) { |
| // The pointers-from-here-are-interesting flag isn't updated dynamically |
| // on from-space pages, so it might be out of sync with the marking state. |
| if (page->heap()->incremental_marking()->IsMarking()) { |
| CHECK(page->IsFlagSet(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING)); |
| } else { |
| CHECK( |
| !page->IsFlagSet(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING)); |
| } |
| } |
| for (int i = 0; i < kNumTypes; i++) { |
| ExternalBackingStoreType t = static_cast<ExternalBackingStoreType>(i); |
| external_backing_store_bytes[t] += page->ExternalBackingStoreBytes(t); |
| } |
| |
| CHECK_IMPLIES(page->list_node().prev(), |
| page->list_node().prev()->list_node().<
|