blob: fcf1131b66654057dada17bc099bacd660706564 [file] [log] [blame]
// 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 <utility>
#include "src/base/bits.h"
#include "src/base/macros.h"
#include "src/base/platform/semaphore.h"
#include "src/base/template-utils.h"
#include "src/counters.h"
#include "src/heap/array-buffer-tracker.h"
#include "src/heap/concurrent-marking.h"
#include "src/heap/gc-tracer.h"
#include "src/heap/heap-controller.h"
#include "src/heap/incremental-marking.h"
#include "src/heap/mark-compact.h"
#include "src/heap/slot-set.h"
#include "src/heap/sweeper.h"
#include "src/msan.h"
#include "src/objects-inl.h"
#include "src/objects/js-array-inl.h"
#include "src/snapshot/snapshot.h"
#include "src/v8.h"
#include "src/vm-state-inl.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// HeapObjectIterator
HeapObjectIterator::HeapObjectIterator(PagedSpace* space)
: cur_addr_(kNullAddress),
cur_end_(kNullAddress),
space_(space),
page_range_(space->first_page(), nullptr),
current_page_(page_range_.begin()) {}
HeapObjectIterator::HeapObjectIterator(Page* page)
: cur_addr_(kNullAddress),
cur_end_(kNullAddress),
space_(reinterpret_cast<PagedSpace*>(page->owner())),
page_range_(page),
current_page_(page_range_.begin()) {
#ifdef DEBUG
Space* owner = page->owner();
DCHECK(owner == page->heap()->old_space() ||
owner == page->heap()->map_space() ||
owner == page->heap()->code_space() ||
owner == page->heap()->read_only_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 HeapObjectIterator::AdvanceToNextPage() {
DCHECK_EQ(cur_addr_, cur_end_);
if (current_page_ == page_range_.end()) return false;
Page* cur_page = *(current_page_++);
Heap* heap = space_->heap();
heap->mark_compact_collector()->sweeper()->EnsurePageIsIterable(cur_page);
#ifdef ENABLE_MINOR_MC
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.has_next();) {
it.next()->PauseAllocationObservers();
}
}
PauseAllocationObserversScope::~PauseAllocationObserversScope() {
for (SpaceIterator it(heap_); it.has_next();) {
it.next()->ResumeAllocationObservers();
}
}
// -----------------------------------------------------------------------------
// CodeRange
CodeRange::CodeRange(Isolate* isolate, size_t requested)
: isolate_(isolate),
free_list_(0),
allocation_list_(0),
current_allocation_block_index_(0) {
DCHECK(!virtual_memory_.IsReserved());
if (requested == 0) {
// 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.
if (kRequiresCodeRange) {
requested = kMaximalCodeRangeSize;
} else {
return;
}
}
if (requested <= kMinimumCodeRangeSize) {
requested = kMinimumCodeRangeSize;
}
const size_t reserved_area =
kReservedCodeRangePages * MemoryAllocator::GetCommitPageSize();
if (requested < (kMaximalCodeRangeSize - reserved_area))
requested += reserved_area;
DCHECK(!kRequiresCodeRange || requested <= kMaximalCodeRangeSize);
VirtualMemory reservation;
if (!AlignedAllocVirtualMemory(
requested, Max(kCodeRangeAreaAlignment, AllocatePageSize()),
GetRandomMmapAddr(), &reservation)) {
V8::FatalProcessOutOfMemory(isolate,
"CodeRange setup: allocate virtual memory");
}
// 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.
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 = reservation.size() - (aligned_base - base) - reserved_area;
allocation_list_.emplace_back(aligned_base, size);
current_allocation_block_index_ = 0;
LOG(isolate_,
NewEvent("CodeRange", reinterpret_cast<void*>(reservation.address()),
requested));
virtual_memory_.TakeControl(&reservation);
}
bool CodeRange::CompareFreeBlockAddress(const FreeBlock& left,
const FreeBlock& right) {
return left.start < right.start;
}
bool CodeRange::GetNextAllocationBlock(size_t requested) {
for (current_allocation_block_index_++;
current_allocation_block_index_ < allocation_list_.size();
current_allocation_block_index_++) {
if (requested <= allocation_list_[current_allocation_block_index_].size) {
return true; // Found a large enough allocation block.
}
}
// Sort and merge the free blocks on the free list and the allocation list.
free_list_.insert(free_list_.end(), allocation_list_.begin(),
allocation_list_.end());
allocation_list_.clear();
std::sort(free_list_.begin(), free_list_.end(), &CompareFreeBlockAddress);
for (size_t i = 0; i < free_list_.size();) {
FreeBlock merged = free_list_[i];
i++;
// Add adjacent free blocks to the current merged block.
while (i < free_list_.size() &&
free_list_[i].start == merged.start + merged.size) {
merged.size += free_list_[i].size;
i++;
}
if (merged.size > 0) {
allocation_list_.push_back(merged);
}
}
free_list_.clear();
for (current_allocation_block_index_ = 0;
current_allocation_block_index_ < allocation_list_.size();
current_allocation_block_index_++) {
if (requested <= allocation_list_[current_allocation_block_index_].size) {
return true; // Found a large enough allocation block.
}
}
current_allocation_block_index_ = 0;
// Code range is full or too fragmented.
return false;
}
Address CodeRange::AllocateRawMemory(const size_t requested_size,
const size_t commit_size,
size_t* allocated) {
// requested_size includes the header and two guard regions, while commit_size
// only includes the header.
DCHECK_LE(commit_size,
requested_size - 2 * MemoryAllocator::CodePageGuardSize());
FreeBlock current;
if (!ReserveBlock(requested_size, &current)) {
*allocated = 0;
return kNullAddress;
}
*allocated = current.size;
DCHECK(IsAddressAligned(current.start, MemoryChunk::kAlignment));
if (!isolate_->heap()->memory_allocator()->CommitExecutableMemory(
&virtual_memory_, current.start, commit_size, *allocated)) {
*allocated = 0;
ReleaseBlock(&current);
return kNullAddress;
}
return current.start;
}
void CodeRange::FreeRawMemory(Address address, size_t length) {
DCHECK(IsAddressAligned(address, MemoryChunk::kAlignment));
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
free_list_.emplace_back(address, length);
virtual_memory_.SetPermissions(address, length, PageAllocator::kNoAccess);
}
bool CodeRange::ReserveBlock(const size_t requested_size, FreeBlock* block) {
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
DCHECK(allocation_list_.empty() ||
current_allocation_block_index_ < allocation_list_.size());
if (allocation_list_.empty() ||
requested_size > allocation_list_[current_allocation_block_index_].size) {
// Find an allocation block large enough.
if (!GetNextAllocationBlock(requested_size)) return false;
}
// Commit the requested memory at the start of the current allocation block.
size_t aligned_requested = ::RoundUp(requested_size, MemoryChunk::kAlignment);
*block = allocation_list_[current_allocation_block_index_];
// Don't leave a small free block, useless for a large object or chunk.
if (aligned_requested < (block->size - Page::kPageSize)) {
block->size = aligned_requested;
}
DCHECK(IsAddressAligned(block->start, MemoryChunk::kAlignment));
allocation_list_[current_allocation_block_index_].start += block->size;
allocation_list_[current_allocation_block_index_].size -= block->size;
return true;
}
void CodeRange::ReleaseBlock(const FreeBlock* block) {
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
free_list_.push_back(*block);
}
// -----------------------------------------------------------------------------
// MemoryAllocator
//
MemoryAllocator::MemoryAllocator(Isolate* isolate, size_t capacity,
size_t code_range_size)
: isolate_(isolate),
code_range_(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) {
code_range_ = new CodeRange(isolate_, code_range_size);
}
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();
}
delete code_range_;
code_range_ = 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]) !=
CancelableTaskManager::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::PrepareForMarkCompact() {
CancelAndWaitForPendingTasks();
// 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());
}
}
int MemoryAllocator::Unmapper::NumberOfChunks() {
base::LockGuard<base::Mutex> 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::LockGuard<base::Mutex> 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(Address base, size_t size) {
if (!SetPermissions(base, size, PageAllocator::kReadWrite)) {
return false;
}
UpdateAllocatedSpaceLimits(base, base + size);
return true;
}
void MemoryAllocator::FreeMemory(VirtualMemory* reservation,
Executability executable) {
// TODO(gc) make code_range part of memory allocator?
// Code which is part of the code-range does not have its own VirtualMemory.
DCHECK(code_range() == nullptr ||
!code_range()->contains(reservation->address()));
DCHECK(executable == NOT_EXECUTABLE || !code_range()->valid() ||
reservation->size() <= Page::kPageSize);
reservation->Free();
}
void MemoryAllocator::FreeMemory(Address base, size_t size,
Executability executable) {
// TODO(gc) make code_range part of memory allocator?
if (code_range() != nullptr && code_range()->contains(base)) {
DCHECK(executable == EXECUTABLE);
code_range()->FreeRawMemory(base, size);
} else {
DCHECK(executable == NOT_EXECUTABLE || !code_range()->valid());
CHECK(FreePages(reinterpret_cast<void*>(base), size));
}
}
Address MemoryAllocator::ReserveAlignedMemory(size_t size, size_t alignment,
void* hint,
VirtualMemory* controller) {
VirtualMemory reservation;
if (!AlignedAllocVirtualMemory(size, alignment, hint, &reservation)) {
return kNullAddress;
}
Address result = reservation.address();
size_ += reservation.size();
controller->TakeControl(&reservation);
return result;
}
Address MemoryAllocator::AllocateAlignedMemory(
size_t reserve_size, size_t commit_size, size_t alignment,
Executability executable, void* hint, VirtualMemory* controller) {
DCHECK(commit_size <= reserve_size);
VirtualMemory reservation;
Address base =
ReserveAlignedMemory(reserve_size, alignment, hint, &reservation);
if (base == kNullAddress) return kNullAddress;
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->TakeControl(&reservation);
return base;
}
Heap* MemoryChunk::synchronized_heap() {
return reinterpret_cast<Heap*>(
base::Acquire_Load(reinterpret_cast<base::AtomicWord*>(&heap_)));
}
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::SetReadAndExecutable() {
DCHECK(IsFlagSet(MemoryChunk::IS_EXECUTABLE));
DCHECK(owner()->identity() == CODE_SPACE || owner()->identity() == LO_SPACE);
// Decrementing the write_unprotect_counter_ and changing the page
// protection mode has to be atomic.
base::LockGuard<base::Mutex> 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() + MemoryAllocator::CodePageAreaStartOffset();
size_t page_size = MemoryAllocator::GetCommitPageSize();
DCHECK(IsAddressAligned(protect_start, page_size));
size_t protect_size = RoundUp(area_size(), page_size);
CHECK(SetPermissions(protect_start, protect_size,
PageAllocator::kReadExecute));
}
}
void MemoryChunk::SetReadAndWritable() {
DCHECK(IsFlagSet(MemoryChunk::IS_EXECUTABLE));
DCHECK(owner()->identity() == CODE_SPACE || owner()->identity() == LO_SPACE);
// Incrementing the write_unprotect_counter_ and changing the page
// protection mode has to be atomic.
base::LockGuard<base::Mutex> guard(page_protection_change_mutex_);
write_unprotect_counter_++;
DCHECK_LE(write_unprotect_counter_, kMaxWriteUnprotectCounter);
if (write_unprotect_counter_ == 1) {
Address unprotect_start =
address() + MemoryAllocator::CodePageAreaStartOffset();
size_t page_size = MemoryAllocator::GetCommitPageSize();
DCHECK(IsAddressAligned(unprotect_start, page_size));
size_t unprotect_size = RoundUp(area_size(), page_size);
CHECK(SetPermissions(unprotect_start, unprotect_size,
PageAllocator::kReadWrite));
}
}
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(base == chunk->address());
chunk->heap_ = heap;
chunk->size_ = size;
chunk->area_start_ = area_start;
chunk->area_end_ = area_end;
chunk->flags_ = Flags(NO_FLAGS);
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->skip_list_ = 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;
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
chunk->categories_[i] = nullptr;
}
if (owner->identity() == RO_SPACE) {
heap->incremental_marking()
->non_atomic_marking_state()
->bitmap(chunk)
->MarkAllBits();
} else {
heap->incremental_marking()->non_atomic_marking_state()->ClearLiveness(
chunk);
}
DCHECK_EQ(kFlagsOffset, OFFSET_OF(MemoryChunk, flags_));
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(IsAddressAligned(area_start, page_size));
size_t area_size = RoundUp(area_end - area_start, page_size);
CHECK(SetPermissions(area_start, area_size,
PageAllocator::kReadWriteExecute));
}
}
if (reservation != nullptr) {
chunk->reservation_.TakeControl(reservation);
}
return chunk;
}
Page* PagedSpace::InitializePage(MemoryChunk* chunk, Executability executable) {
Page* page = static_cast<Page*>(chunk);
DCHECK_GE(Page::kAllocatableMemory, page->area_size());
// Make sure that categories are initialized before freeing the area.
page->ResetAllocatedBytes();
page->SetOldGenerationPageFlags(heap()->incremental_marking()->IsMarking());
page->AllocateFreeListCategories();
page->InitializeFreeListCategories();
page->list_node().Initialize();
page->InitializationMemoryFence();
return page;
}
Page* SemiSpace::InitializePage(MemoryChunk* chunk, Executability executable) {
DCHECK_EQ(executable, Executability::NOT_EXECUTABLE);
bool in_to_space = (id() != kFromSpace);
chunk->SetFlag(in_to_space ? MemoryChunk::IN_TO_SPACE
: MemoryChunk::IN_FROM_SPACE);
DCHECK(!chunk->IsFlagSet(in_to_space ? MemoryChunk::IN_FROM_SPACE
: MemoryChunk::IN_TO_SPACE));
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());
LargePage* page = static_cast<LargePage*>(chunk);
page->list_node().Initialize();
return page;
}
void Page::AllocateFreeListCategories() {
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
categories_[i] = new FreeListCategory(
reinterpret_cast<PagedSpace*>(owner())->free_list(), this);
}
}
void Page::InitializeFreeListCategories() {
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
categories_[i]->Initialize(static_cast<FreeListCategoryType>(i));
}
}
void Page::ReleaseFreeListCategories() {
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
if (categories_[i] != nullptr) {
delete categories_[i];
categories_[i] = 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, NOT_EXECUTABLE);
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::IsPagedSpace() const {
return owner()->identity() != LO_SPACE;
}
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 + kObjectStartOffset)
// | 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(
CodePageAreaStartOffset() + reserve_area_size + CodePageGuardSize(),
GetCommitPageSize());
// Size of header (not executable) plus area (executable).
size_t commit_size = ::RoundUp(
CodePageGuardStartOffset() + commit_area_size, GetCommitPageSize());
// Allocate executable memory either from code range or from the OS.
#ifdef V8_TARGET_ARCH_MIPS64
// Use code range only for large object space on mips64 to keep address
// range within 256-MB memory region.
if (code_range()->valid() && reserve_area_size > CodePageAreaSize()) {
#else
if (code_range()->valid()) {
#endif
base =
code_range()->AllocateRawMemory(chunk_size, commit_size, &chunk_size);
DCHECK(IsAligned(base, MemoryChunk::kAlignment));
if (base == kNullAddress) return nullptr;
size_ += chunk_size;
// Update executable memory size.
size_executable_ += chunk_size;
} else {
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, CodePageGuardStartOffset(), kZapValue);
ZapBlock(base + CodePageAreaStartOffset(), commit_area_size, kZapValue);
}
area_start = base + CodePageAreaStartOffset();
area_end = area_start + commit_area_size;
} else {
chunk_size = ::RoundUp(MemoryChunk::kObjectStartOffset + reserve_area_size,
GetCommitPageSize());
size_t commit_size =
::RoundUp(MemoryChunk::kObjectStartOffset + 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, Page::kObjectStartOffset + commit_area_size, kZapValue);
}
area_start = base + Page::kObjectStartOffset;
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_.TakeControl(&reservation);
UncommitBlock(last_chunk_.address(), last_chunk_.size());
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, &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::ResetAllocatedBytes() { allocated_bytes_ = area_size(); }
void Page::AllocateLocalTracker() {
DCHECK_NULL(local_tracker_);
local_tracker_ = new LocalArrayBufferTracker(this);
}
bool Page::contains_array_buffers() {
return local_tracker_ != nullptr && !local_tracker_->IsEmpty();
}
void Page::ResetFreeListStatistics() {
wasted_memory_ = 0;
}
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->size_ -= bytes_to_free;
chunk->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() + 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::PreFreeMemory(MemoryChunk* chunk) {
DCHECK(!chunk->IsFlagSet(MemoryChunk::PRE_FREED));
LOG(isolate_, DeleteEvent("MemoryChunk", chunk));
isolate_->heap()->RememberUnmappedPage(reinterpret_cast<Address>(chunk),
chunk->IsEvacuationCandidate());
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;
}
chunk->SetFlag(MemoryChunk::PRE_FREED);
if (chunk->executable()) UnregisterExecutableMemoryChunk(chunk);
}
void MemoryAllocator::PerformFreeMemory(MemoryChunk* chunk) {
DCHECK(chunk->IsFlagSet(MemoryChunk::PRE_FREED));
chunk->ReleaseAllocatedMemory();
VirtualMemory* reservation = chunk->reserved_memory();
if (chunk->IsFlagSet(MemoryChunk::POOLED)) {
UncommitBlock(reinterpret_cast<Address>(chunk), MemoryChunk::kPageSize);
} else {
if (reservation->IsReserved()) {
FreeMemory(reservation, chunk->executable());
} else {
FreeMemory(chunk->address(), chunk->size(), chunk->executable());
}
}
}
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.
FreeMemory(chunk->address(), static_cast<size_t>(MemoryChunk::kPageSize),
Executability::NOT_EXECUTABLE);
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 void MemoryAllocator::Free<MemoryAllocator::kFull>(MemoryChunk* chunk);
template void MemoryAllocator::Free<MemoryAllocator::kAlreadyPooled>(
MemoryChunk* chunk);
template void MemoryAllocator::Free<MemoryAllocator::kPreFreeAndQueue>(
MemoryChunk* chunk);
template 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>(MemoryChunk::kAllocatableMemory));
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, executable);
}
template Page*
MemoryAllocator::AllocatePage<MemoryAllocator::kRegular, PagedSpace>(
size_t size, PagedSpace* owner, Executability executable);
template Page*
MemoryAllocator::AllocatePage<MemoryAllocator::kRegular, SemiSpace>(
size_t size, SemiSpace* owner, Executability executable);
template 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 + MemoryChunk::kObjectStartOffset;
const Address area_end = start + size;
if (!CommitBlock(start, size)) {
return nullptr;
}
VirtualMemory reservation(start, size);
MemoryChunk::Initialize(isolate_->heap(), start, size, area_start, area_end,
NOT_EXECUTABLE, owner, &reservation);
size_ += size;
return chunk;
}
bool MemoryAllocator::CommitBlock(Address start, size_t size) {
if (!CommitMemory(start, size)) return false;
if (Heap::ShouldZapGarbage()) {
ZapBlock(start, size, kZapValue);
}
isolate_->counters()->memory_allocated()->Increment(static_cast<int>(size));
return true;
}
bool MemoryAllocator::UncommitBlock(Address start, size_t size) {
if (!SetPermissions(start, size, PageAllocator::kNoAccess)) return false;
isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
return true;
}
void MemoryAllocator::ZapBlock(Address start, size_t size,
uintptr_t zap_value) {
DCHECK_EQ(start % kPointerSize, 0);
DCHECK_EQ(size % kPointerSize, 0);
for (size_t s = 0; s + kPointerSize <= size; s += kPointerSize) {
Memory::Address_at(start + s) = static_cast<Address>(zap_value);
}
}
size_t MemoryAllocator::CodePageGuardStartOffset() {
// We are guarding code pages: the first OS page after the header
// will be protected as non-writable.
return ::RoundUp(Page::kObjectStartOffset, GetCommitPageSize());
}
size_t MemoryAllocator::CodePageGuardSize() { return GetCommitPageSize(); }
size_t MemoryAllocator::CodePageAreaStartOffset() {
// We are guarding code pages: the first OS page after the header
// will be protected as non-writable.
return CodePageGuardStartOffset() + CodePageGuardSize();
}
size_t MemoryAllocator::CodePageAreaEndOffset() {
// We are guarding code pages: the last OS page will be protected as
// non-writable.
return Page::kPageSize - static_cast<int>(GetCommitPageSize());
}
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();
}
}
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(IsAddressAligned(start, page_size));
DCHECK_EQ(0, commit_size % page_size);
DCHECK_EQ(0, reserved_size % page_size);
const size_t guard_size = CodePageGuardSize();
const size_t pre_guard_offset = CodePageGuardStartOffset();
const size_t code_area_offset = CodePageAreaStartOffset();
// 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::ReleaseAllocatedMemory() {
if (skip_list_ != nullptr) {
delete skip_list_;
skip_list_ = nullptr;
}
if (mutex_ != nullptr) {
delete mutex_;
mutex_ = nullptr;
}
if (page_protection_change_mutex_ != nullptr) {
delete page_protection_change_mutex_;
page_protection_change_mutex_ = 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();
if (IsPagedSpace()) {
Page* page = static_cast<Page*>(this);
page->ReleaseFreeListCategories();
}
}
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 SlotSet* MemoryChunk::AllocateSlotSet<OLD_TO_NEW>();
template 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);
}
}
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;
}
void MemoryChunk::IncrementExternalBackingStoreBytes(
ExternalBackingStoreType type, size_t amount) {
external_backing_store_bytes_[type] += amount;
owner()->IncrementExternalBackingStoreBytes(type, amount);
}
void MemoryChunk::DecrementExternalBackingStoreBytes(
ExternalBackingStoreType type, size_t amount) {
DCHECK_GE(external_backing_store_bytes_[type], amount);
external_backing_store_bytes_[type] -= amount;
owner()->DecrementExternalBackingStoreBytes(type, amount);
}
// -----------------------------------------------------------------------------
// PagedSpace implementation
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)
: SpaceWithLinearArea(heap, space), executable_(executable) {
area_size_ = MemoryAllocator::PageAreaSize(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;
}
MarkCompactCollector* collector = heap()->mark_compact_collector();
size_t added = 0;
{
Page* p = nullptr;
while ((p = collector->sweeper()->GetSweptPageSafe(this)) != nullptr) {
// 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::LockGuard<base::Mutex> guard(owner->mutex());
owner->RefineAllocatedBytesAfterSweeping(p);
owner->RemovePage(p);
added += AddPage(p);
} else {
base::LockGuard<base::Mutex> 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::LockGuard<base::Mutex> 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_EQ(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::LockGuard<base::Mutex> guard(mutex());
// Check for pages that still contain free list entries. Bail out for smaller
// categories.
const int minimum_category =
static_cast<int>(FreeList::SelectFreeListCategoryType(size_in_bytes));
Page* page = free_list()->GetPageForCategoryType(kHuge);
if (!page && static_cast<int>(kLarge) >= minimum_category)
page = free_list()->GetPageForCategoryType(kLarge);
if (!page && static_cast<int>(kMedium) >= minimum_category)
page = free_list()->GetPageForCategoryType(kMedium);
if (!page && static_cast<int>(kSmall) >= minimum_category)
page = free_list()->GetPageForCategoryType(kSmall);
if (!page && static_cast<int>(kTiny) >= minimum_category)
page = free_list()->GetPageForCategoryType(kTiny);
if (!page && static_cast<int>(kTiniest) >= minimum_category)
page = free_list()->GetPageForCategoryType(kTiniest);
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::LockGuard<base::Mutex> 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);
return true;
}
int PagedSpace::CountTotalPages() {
int count = 0;
for (Page* page : *this) {
count++;
USE(page);
}
return count;
}
void PagedSpace::ResetFreeListStatistics() {
for (Page* page : *this) {
page->ResetFreeListStatistics();
}
}
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::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 HeapObjectIterator(this));
}
bool PagedSpace::RefillLinearAllocationAreaFromFreeList(size_t size_in_bytes) {
DCHECK(IsAligned(size_in_bytes, kPointerSize));
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 == nullptr) 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::FromAddress(new_node->address());
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());
HeapObjectIterator it(page);
Address end_of_previous_object = page->area_start();
Address top = page->area_end();
for (HeapObject* object = it.Next(); object != nullptr;
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(heap()->map_space()->Contains(map) ||
heap()->read_only_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) {
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 = NumberToSize(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());
HeapObjectIterator it(page);
int black_size = 0;
for (HeapObject* object = it.Next(); object != nullptr;
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();
HeapObjectIterator it(page);
size_t real_allocated = 0;
for (HeapObject* object = it.Next(); object != nullptr;
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, size_t initial_semispace_capacity,
size_t max_semispace_capacity)
: SpaceWithLinearArea(heap, NEW_SPACE),
to_space_(heap, kToSpace),
from_space_(heap, kFromSpace),
reservation_() {
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::kIsInNewSpaceMask);
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>(
Page::kAllocatableMemory, 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()->flags(),
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)
: 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) {
*this = other;
}
LocalAllocationBuffer& LocalAllocationBuffer::operator=(
const LocalAllocationBuffer& other) {
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());
original_top_ = top();
original_limit_ = limit();
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()->ClearLiveness(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(!Page::IsAtObjectStart(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::LockGuard<base::Mutex> 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() {
return ObjectSizeFor(heap()->memory_allocator()->Available());
}
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 SemiSpaceIterator(this));
}
#ifdef VERIFY_HEAP
// We do not use the SemiSpaceIterator because verification doesn't assume
// that it works (it depends on the invariants we are checking).
void NewSpace::Verify(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(heap()->map_space()->Contains(map) ||
heap()->read_only_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 = NumberToSize(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++) {
Page* new_page =
heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>(
Page::kAllocatableMemory, 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() {