// 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/platform/platform.h"
#include "src/base/platform/semaphore.h"
#include "src/counters.h"
#include "src/full-codegen/full-codegen.h"
#include "src/heap/array-buffer-tracker.h"
#include "src/heap/incremental-marking.h"
#include "src/heap/mark-compact.h"
#include "src/heap/slot-set.h"
#include "src/macro-assembler.h"
#include "src/msan.h"
#include "src/objects-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_(nullptr),
cur_end_(nullptr),
space_(space),
page_range_(space->anchor()->next_page(), space->anchor()),
current_page_(page_range_.begin()) {}
HeapObjectIterator::HeapObjectIterator(Page* page)
: cur_addr_(nullptr),
cur_end_(nullptr),
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());
#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().SweepOrWaitUntilSweepingCompleted(
cur_page);
if (cur_page->IsFlagSet(Page::SWEEP_TO_ITERATE))
heap->minor_mark_compact_collector()->MakeIterable(
cur_page, MarkingTreatmentMode::CLEAR,
FreeSpaceTreatmentMode::IGNORE_FREE_SPACE);
cur_addr_ = cur_page->area_start();
cur_end_ = cur_page->area_end();
DCHECK(cur_page->SweepingDone());
return true;
}
PauseAllocationObserversScope::PauseAllocationObserversScope(Heap* heap)
: heap_(heap) {
AllSpaces spaces(heap_);
for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
space->PauseAllocationObservers();
}
}
PauseAllocationObserversScope::~PauseAllocationObserversScope() {
AllSpaces spaces(heap_);
for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
space->ResumeAllocationObservers();
}
}
// -----------------------------------------------------------------------------
// CodeRange
CodeRange::CodeRange(Isolate* isolate)
: isolate_(isolate),
code_range_(NULL),
free_list_(0),
allocation_list_(0),
current_allocation_block_index_(0) {}
bool CodeRange::SetUp(size_t requested) {
DCHECK(code_range_ == NULL);
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 true;
}
}
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);
code_range_ = new base::VirtualMemory(
requested, Max(kCodeRangeAreaAlignment,
static_cast<size_t>(base::OS::AllocateAlignment())));
CHECK(code_range_ != NULL);
if (!code_range_->IsReserved()) {
delete code_range_;
code_range_ = NULL;
return false;
}
// We are sure that we have mapped a block of requested addresses.
DCHECK(code_range_->size() == requested);
Address base = reinterpret_cast<Address>(code_range_->address());
// On some platforms, specifically Win64, we need to reserve some pages at
// the beginning of an executable space.
if (reserved_area > 0) {
if (!code_range_->Commit(base, reserved_area, true)) {
delete code_range_;
code_range_ = NULL;
return false;
}
base += reserved_area;
}
Address aligned_base = RoundUp(base, MemoryChunk::kAlignment);
size_t size = code_range_->size() - (aligned_base - base) - reserved_area;
allocation_list_.Add(FreeBlock(aligned_base, size));
current_allocation_block_index_ = 0;
LOG(isolate_, NewEvent("CodeRange", code_range_->address(), requested));
return true;
}
int CodeRange::CompareFreeBlockAddress(const FreeBlock* left,
const FreeBlock* right) {
// The entire point of CodeRange is that the difference between two
// addresses in the range can be represented as a signed 32-bit int,
// so the cast is semantically correct.
return static_cast<int>(left->start - right->start);
}
bool CodeRange::GetNextAllocationBlock(size_t requested) {
for (current_allocation_block_index_++;
current_allocation_block_index_ < allocation_list_.length();
current_allocation_block_index_++) {
if (requested <= allocation_list_[current_allocation_block_index_].size) {
return true; // Found a large enough allocation block.
}
}
// Sort and merge the free blocks on the free list and the allocation list.
free_list_.AddAll(allocation_list_);
allocation_list_.Clear();
free_list_.Sort(&CompareFreeBlockAddress);
for (int i = 0; i < free_list_.length();) {
FreeBlock merged = free_list_[i];
i++;
// Add adjacent free blocks to the current merged block.
while (i < free_list_.length() &&
free_list_[i].start == merged.start + merged.size) {
merged.size += free_list_[i].size;
i++;
}
if (merged.size > 0) {
allocation_list_.Add(merged);
}
}
free_list_.Clear();
for (current_allocation_block_index_ = 0;
current_allocation_block_index_ < allocation_list_.length();
current_allocation_block_index_++) {
if (requested <= allocation_list_[current_allocation_block_index_].size) {
return 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) {
// request_size includes guards while committed_size does not. Make sure
// callers know about the invariant.
CHECK_LE(commit_size,
requested_size - 2 * MemoryAllocator::CodePageGuardSize());
FreeBlock current;
if (!ReserveBlock(requested_size, ¤t)) {
*allocated = 0;
return NULL;
}
*allocated = current.size;
DCHECK(*allocated <= current.size);
DCHECK(IsAddressAligned(current.start, MemoryChunk::kAlignment));
if (!isolate_->heap()->memory_allocator()->CommitExecutableMemory(
code_range_, current.start, commit_size, *allocated)) {
*allocated = 0;
ReleaseBlock(¤t);
return NULL;
}
return current.start;
}
bool CodeRange::CommitRawMemory(Address start, size_t length) {
return isolate_->heap()->memory_allocator()->CommitMemory(start, length,
EXECUTABLE);
}
bool CodeRange::UncommitRawMemory(Address start, size_t length) {
return code_range_->Uncommit(start, length);
}
void CodeRange::FreeRawMemory(Address address, size_t length) {
DCHECK(IsAddressAligned(address, MemoryChunk::kAlignment));
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
free_list_.Add(FreeBlock(address, length));
code_range_->Uncommit(address, length);
}
void CodeRange::TearDown() {
delete code_range_; // Frees all memory in the virtual memory range.
code_range_ = NULL;
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
free_list_.Free();
allocation_list_.Free();
}
bool CodeRange::ReserveBlock(const size_t requested_size, FreeBlock* block) {
base::LockGuard<base::Mutex> guard(&code_range_mutex_);
DCHECK(allocation_list_.length() == 0 ||
current_allocation_block_index_ < allocation_list_.length());
if (allocation_list_.length() == 0 ||
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_.Add(*block);
}
// -----------------------------------------------------------------------------
// MemoryAllocator
//
MemoryAllocator::MemoryAllocator(Isolate* isolate)
: isolate_(isolate),
code_range_(nullptr),
capacity_(0),
size_(0),
size_executable_(0),
lowest_ever_allocated_(reinterpret_cast<void*>(-1)),
highest_ever_allocated_(reinterpret_cast<void*>(0)),
unmapper_(this) {}
bool MemoryAllocator::SetUp(size_t capacity, size_t code_range_size) {
capacity_ = RoundUp(capacity, Page::kPageSize);
size_ = 0;
size_executable_ = 0;
code_range_ = new CodeRange(isolate_);
if (!code_range_->SetUp(code_range_size)) return false;
return true;
}
void MemoryAllocator::TearDown() {
unmapper()->TearDown();
// Check that spaces were torn down before MemoryAllocator.
DCHECK_EQ(size_.Value(), 0u);
// TODO(gc) this will be true again when we fix FreeMemory.
// DCHECK(size_executable_ == 0);
capacity_ = 0;
if (last_chunk_.IsReserved()) {
last_chunk_.Release();
}
delete code_range_;
code_range_ = nullptr;
}
class MemoryAllocator::Unmapper::UnmapFreeMemoryTask : public v8::Task {
public:
explicit UnmapFreeMemoryTask(Unmapper* unmapper) : unmapper_(unmapper) {}
private:
// v8::Task overrides.
void Run() override {
unmapper_->PerformFreeMemoryOnQueuedChunks<FreeMode::kUncommitPooled>();
unmapper_->pending_unmapping_tasks_semaphore_.Signal();
}
Unmapper* unmapper_;
DISALLOW_COPY_AND_ASSIGN(UnmapFreeMemoryTask);
};
void MemoryAllocator::Unmapper::FreeQueuedChunks() {
ReconsiderDelayedChunks();
if (FLAG_concurrent_sweeping) {
V8::GetCurrentPlatform()->CallOnBackgroundThread(
new UnmapFreeMemoryTask(this), v8::Platform::kShortRunningTask);
concurrent_unmapping_tasks_active_++;
} else {
PerformFreeMemoryOnQueuedChunks<FreeMode::kUncommitPooled>();
}
}
bool MemoryAllocator::Unmapper::WaitUntilCompleted() {
bool waited = false;
while (concurrent_unmapping_tasks_active_ > 0) {
pending_unmapping_tasks_semaphore_.Wait();
concurrent_unmapping_tasks_active_--;
waited = true;
}
return waited;
}
template <MemoryAllocator::Unmapper::FreeMode mode>
void MemoryAllocator::Unmapper::PerformFreeMemoryOnQueuedChunks() {
MemoryChunk* chunk = nullptr;
// 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);
}
}
// Non-regular chunks.
while ((chunk = GetMemoryChunkSafe<kNonRegular>()) != nullptr) {
allocator_->PerformFreeMemory(chunk);
}
}
void MemoryAllocator::Unmapper::TearDown() {
WaitUntilCompleted();
ReconsiderDelayedChunks();
CHECK(delayed_regular_chunks_.empty());
PerformFreeMemoryOnQueuedChunks<FreeMode::kReleasePooled>();
for (int i = 0; i < kNumberOfChunkQueues; i++) {
DCHECK(chunks_[i].empty());
}
}
void MemoryAllocator::Unmapper::ReconsiderDelayedChunks() {
std::list<MemoryChunk*> delayed_chunks(std::move(delayed_regular_chunks_));
// Move constructed, so the permanent list should be empty.
DCHECK(delayed_regular_chunks_.empty());
for (auto it = delayed_chunks.begin(); it != delayed_chunks.end(); ++it) {
AddMemoryChunkSafe<kRegular>(*it);
}
}
bool MemoryAllocator::CanFreeMemoryChunk(MemoryChunk* chunk) {
MarkCompactCollector* mc = isolate_->heap()->mark_compact_collector();
// We cannot free a memory chunk in new space while the sweeper is running
// because the memory chunk can be in the queue of a sweeper task.
// Chunks in old generation are unmapped if they are empty.
DCHECK(chunk->InNewSpace() || chunk->SweepingDone());
return !chunk->InNewSpace() || mc == nullptr || !FLAG_concurrent_sweeping ||
!mc->sweeper().sweeping_in_progress();
}
bool MemoryAllocator::CommitMemory(Address base, size_t size,
Executability executable) {
if (!base::VirtualMemory::CommitRegion(base, size,
executable == EXECUTABLE)) {
return false;
}
UpdateAllocatedSpaceLimits(base, base + size);
return true;
}
void MemoryAllocator::FreeMemory(base::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() == NULL ||
!code_range()->contains(static_cast<Address>(reservation->address())));
DCHECK(executable == NOT_EXECUTABLE || !code_range()->valid() ||
reservation->size() <= Page::kPageSize);
reservation->Release();
}
void MemoryAllocator::FreeMemory(Address base, size_t size,
Executability executable) {
// TODO(gc) make code_range part of memory allocator?
if (code_range() != NULL &&
code_range()->contains(static_cast<Address>(base))) {
DCHECK(executable == EXECUTABLE);
code_range()->FreeRawMemory(base, size);
} else {
DCHECK(executable == NOT_EXECUTABLE || !code_range()->valid());
bool result = base::VirtualMemory::ReleaseRegion(base, size);
USE(result);
DCHECK(result);
}
}
Address MemoryAllocator::ReserveAlignedMemory(size_t size, size_t alignment,
base::VirtualMemory* controller) {
base::VirtualMemory reservation(size, alignment);
if (!reservation.IsReserved()) return NULL;
size_.Increment(reservation.size());
Address base =
RoundUp(static_cast<Address>(reservation.address()), alignment);
controller->TakeControl(&reservation);
return base;
}
Address MemoryAllocator::AllocateAlignedMemory(
size_t reserve_size, size_t commit_size, size_t alignment,
Executability executable, base::VirtualMemory* controller) {
DCHECK(commit_size <= reserve_size);
base::VirtualMemory reservation;
Address base = ReserveAlignedMemory(reserve_size, alignment, &reservation);
if (base == NULL) return NULL;
if (executable == EXECUTABLE) {
if (!CommitExecutableMemory(&reservation, base, commit_size,
reserve_size)) {
base = NULL;
}
} else {
if (reservation.Commit(base, commit_size, false)) {
UpdateAllocatedSpaceLimits(base, base + commit_size);
} else {
base = NULL;
}
}
if (base == NULL) {
// Failed to commit the body. Release the mapping and any partially
// commited regions inside it.
reservation.Release();
size_.Decrement(reserve_size);
return NULL;
}
controller->TakeControl(&reservation);
return base;
}
void Page::InitializeAsAnchor(Space* space) {
set_owner(space);
set_next_chunk(this);
set_prev_chunk(this);
SetFlags(0, static_cast<uintptr_t>(~0));
SetFlag(ANCHOR);
}
MemoryChunk* MemoryChunk::Initialize(Heap* heap, Address base, size_t size,
Address area_start, Address area_end,
Executability executable, Space* owner,
base::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();
chunk->slot_set_[OLD_TO_NEW].SetValue(nullptr);
chunk->slot_set_[OLD_TO_OLD].SetValue(nullptr);
chunk->typed_slot_set_[OLD_TO_NEW].SetValue(nullptr);
chunk->typed_slot_set_[OLD_TO_OLD].SetValue(nullptr);
chunk->skip_list_ = nullptr;
chunk->progress_bar_ = 0;
chunk->high_water_mark_.SetValue(static_cast<intptr_t>(area_start - base));
chunk->concurrent_sweeping_state().SetValue(kSweepingDone);
chunk->mutex_ = new base::RecursiveMutex();
chunk->available_in_free_list_ = 0;
chunk->wasted_memory_ = 0;
chunk->young_generation_bitmap_ = nullptr;
chunk->set_next_chunk(nullptr);
chunk->set_prev_chunk(nullptr);
chunk->local_tracker_ = nullptr;
MarkingState::Internal(chunk).ClearLiveness();
DCHECK(OFFSET_OF(MemoryChunk, flags_) == kFlagsOffset);
if (executable == EXECUTABLE) {
chunk->SetFlag(IS_EXECUTABLE);
}
if (reservation != nullptr) {
chunk->reservation_.TakeControl(reservation);
}
return chunk;
}
// Commit MemoryChunk area to the requested size.
bool MemoryChunk::CommitArea(size_t requested) {
size_t guard_size =
IsFlagSet(IS_EXECUTABLE) ? MemoryAllocator::CodePageGuardSize() : 0;
size_t header_size = area_start() - address() - guard_size;
size_t commit_size =
RoundUp(header_size + requested, MemoryAllocator::GetCommitPageSize());
size_t committed_size = RoundUp(header_size + (area_end() - area_start()),
MemoryAllocator::GetCommitPageSize());
if (commit_size > committed_size) {
// Commit size should be less or equal than the reserved size.
DCHECK(commit_size <= size() - 2 * guard_size);
// Append the committed area.
Address start = address() + committed_size + guard_size;
size_t length = commit_size - committed_size;
if (reservation_.IsReserved()) {
Executability executable =
IsFlagSet(IS_EXECUTABLE) ? EXECUTABLE : NOT_EXECUTABLE;
if (!heap()->memory_allocator()->CommitMemory(start, length,
executable)) {
return false;
}
} else {
CodeRange* code_range = heap_->memory_allocator()->code_range();
DCHECK(code_range->valid() && IsFlagSet(IS_EXECUTABLE));
if (!code_range->CommitRawMemory(start, length)) return false;
}
if (Heap::ShouldZapGarbage()) {
heap_->memory_allocator()->ZapBlock(start, length);
}
} else if (commit_size < committed_size) {
DCHECK(commit_size > 0);
// Shrink the committed area.
size_t length = committed_size - commit_size;
Address start = address() + committed_size + guard_size - length;
if (reservation_.IsReserved()) {
if (!reservation_.Uncommit(start, length)) return false;
} else {
CodeRange* code_range = heap_->memory_allocator()->code_range();
DCHECK(code_range->valid() && IsFlagSet(IS_EXECUTABLE));
if (!code_range->UncommitRawMemory(start, length)) return false;
}
}
area_end_ = area_start_ + requested;
return true;
}
size_t MemoryChunk::CommittedPhysicalMemory() {
if (!base::VirtualMemory::HasLazyCommits() || owner()->identity() == LO_SPACE)
return size();
return high_water_mark_.Value();
}
void MemoryChunk::InsertAfter(MemoryChunk* other) {
MemoryChunk* other_next = other->next_chunk();
set_next_chunk(other_next);
set_prev_chunk(other);
other_next->set_prev_chunk(this);
other->set_next_chunk(this);
}
void MemoryChunk::Unlink() {
MemoryChunk* next_element = next_chunk();
MemoryChunk* prev_element = prev_chunk();
next_element->set_prev_chunk(prev_element);
prev_element->set_next_chunk(next_element);
set_prev_chunk(NULL);
set_next_chunk(NULL);
}
void MemoryAllocator::ShrinkChunk(MemoryChunk* chunk, size_t bytes_to_shrink) {
DCHECK_GE(bytes_to_shrink, static_cast<size_t>(GetCommitPageSize()));
DCHECK_EQ(0u, bytes_to_shrink % GetCommitPageSize());
Address free_start = chunk->area_end_ - bytes_to_shrink;
// Don't adjust the size of the page. The area is just uncomitted but not
// released.
chunk->area_end_ -= bytes_to_shrink;
UncommitBlock(free_start, bytes_to_shrink);
if (chunk->IsFlagSet(MemoryChunk::IS_EXECUTABLE)) {
if (chunk->reservation_.IsReserved())
chunk->reservation_.Guard(chunk->area_end_);
else
base::OS::Guard(chunk->area_end_, GetCommitPageSize());
}
}
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 = nullptr;
base::VirtualMemory reservation;
Address area_start = nullptr;
Address area_end = nullptr;
//
// 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,
GetCommitPageSize()) +
CodePageGuardSize();
// 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(reinterpret_cast<intptr_t>(base), MemoryChunk::kAlignment));
if (base == NULL) return NULL;
size_.Increment(chunk_size);
// Update executable memory size.
size_executable_.Increment(chunk_size);
} else {
base = AllocateAlignedMemory(chunk_size, commit_size,
MemoryChunk::kAlignment, executable,
&reservation);
if (base == NULL) return NULL;
// Update executable memory size.
size_executable_.Increment(reservation.size());
}
if (Heap::ShouldZapGarbage()) {
ZapBlock(base, CodePageGuardStartOffset());
ZapBlock(base + CodePageAreaStartOffset(), commit_area_size);
}
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, &reservation);
if (base == NULL) return NULL;
if (Heap::ShouldZapGarbage()) {
ZapBlock(base, Page::kObjectStartOffset + commit_area_size);
}
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", 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 ((reinterpret_cast<uintptr_t>(base) + chunk_size) == 0u) {
CHECK(!last_chunk_.IsReserved());
last_chunk_.TakeControl(&reservation);
UncommitBlock(reinterpret_cast<Address>(last_chunk_.address()),
last_chunk_.size());
size_.Decrement(chunk_size);
if (executable == EXECUTABLE) {
size_executable_.Decrement(chunk_size);
}
CHECK(last_chunk_.IsReserved());
return AllocateChunk(reserve_area_size, commit_area_size, executable,
owner);
}
return MemoryChunk::Initialize(heap, base, chunk_size, area_start, area_end,
executable, owner, &reservation);
}
void Page::ResetFreeListStatistics() {
wasted_memory_ = 0;
available_in_free_list_ = 0;
}
size_t Page::AvailableInFreeList() {
size_t sum = 0;
ForAllFreeListCategories([&sum](FreeListCategory* category) {
sum += category->available();
});
return sum;
}
size_t Page::ShrinkToHighWaterMark() {
// 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());
if (!filler->IsFreeSpace()) return 0;
#ifdef DEBUG
// Check the the filler is indeed the last filler on the page.
HeapObjectIterator it(this);
HeapObject* filler2 = nullptr;
for (HeapObject* obj = it.Next(); obj != nullptr; obj = it.Next()) {
filler2 = HeapObject::FromAddress(obj->address() + obj->Size());
}
if (filler2 == nullptr || filler2->address() == area_end()) return 0;
DCHECK(filler2->IsFiller());
// The deserializer might leave behind fillers. In this case we need to
// iterate even further.
while ((filler2->address() + filler2->Size()) != area_end()) {
filler2 = HeapObject::FromAddress(filler2->address() + filler2->Size());
DCHECK(filler2->IsFiller());
}
DCHECK_EQ(filler->address(), filler2->address());
#endif // DEBUG
size_t unused = RoundDown(
static_cast<size_t>(area_end() - filler->address() - FreeSpace::kSize),
MemoryAllocator::GetCommitPageSize());
if (unused > 0) {
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()->ShrinkChunk(this, unused);
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);
MarkingState::Internal(this).bitmap()->SetRange(AddressToMarkbitIndex(start),
AddressToMarkbitIndex(end));
MarkingState::Internal(this).IncrementLiveBytes(
static_cast<int>(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);
MarkingState::Internal(this).bitmap()->ClearRange(
AddressToMarkbitIndex(start), AddressToMarkbitIndex(end));
MarkingState::Internal(this).IncrementLiveBytes(
-static_cast<int>(end - start));
}
void MemoryAllocator::PartialFreeMemory(MemoryChunk* chunk,
Address start_free) {
// We do not allow partial shrink for code.
DCHECK(chunk->executable() == NOT_EXECUTABLE);
intptr_t size;
base::VirtualMemory* reservation = chunk->reserved_memory();
DCHECK(reservation->IsReserved());
size = static_cast<intptr_t>(reservation->size());
size_t to_free_size = size - (start_free - chunk->address());
DCHECK(size_.Value() >= to_free_size);
size_.Decrement(to_free_size);
isolate_->counters()->memory_allocated()->Decrement(
static_cast<int>(to_free_size));
chunk->set_size(size - to_free_size);
reservation->ReleasePartial(start_free);
}
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());
base::VirtualMemory* reservation = chunk->reserved_memory();
const size_t size =
reservation->IsReserved() ? reservation->size() : chunk->size();
DCHECK_GE(size_.Value(), static_cast<size_t>(size));
size_.Decrement(size);
isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
if (chunk->executable() == EXECUTABLE) {
DCHECK_GE(size_executable_.Value(), size);
size_executable_.Decrement(size);
}
chunk->SetFlag(MemoryChunk::PRE_FREED);
}
void MemoryAllocator::PerformFreeMemory(MemoryChunk* chunk) {
DCHECK(chunk->IsFlagSet(MemoryChunk::PRE_FREED));
chunk->ReleaseAllocatedMemory();
base::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);
// Fall through to kPreFreeAndQueue.
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 Page::Initialize(isolate_->heap(), chunk, executable, owner);
}
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, owner);
}
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(reinterpret_cast<Address>(chunk), size, NOT_EXECUTABLE)) {
return nullptr;
}
base::VirtualMemory reservation(start, size);
MemoryChunk::Initialize(isolate_->heap(), start, size, area_start, area_end,
NOT_EXECUTABLE, owner, &reservation);
size_.Increment(size);
return chunk;
}
bool MemoryAllocator::CommitBlock(Address start, size_t size,
Executability executable) {
if (!CommitMemory(start, size, executable)) return false;
if (Heap::ShouldZapGarbage()) {
ZapBlock(start, size);
}
isolate_->counters()->memory_allocated()->Increment(static_cast<int>(size));
return true;
}
bool MemoryAllocator::UncommitBlock(Address start, size_t size) {
if (!base::VirtualMemory::UncommitRegion(start, size)) return false;
isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
return true;
}
void MemoryAllocator::ZapBlock(Address start, size_t size) {
for (size_t s = 0; s + kPointerSize <= size; s += kPointerSize) {
Memory::Address_at(start + s) = kZapValue;
}
}
#ifdef DEBUG
void MemoryAllocator::ReportStatistics() {
size_t size = Size();
float pct = static_cast<float>(capacity_ - size) / capacity_;
PrintF(" capacity: %zu , used: %" PRIuS ", available: %%%d\n\n",
capacity_, size, static_cast<int>(pct * 100));
}
#endif
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 static_cast<int>(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::IsPowerOfTwo32(FLAG_v8_os_page_size));
return FLAG_v8_os_page_size * KB;
} else {
return base::OS::CommitPageSize();
}
}
bool MemoryAllocator::CommitExecutableMemory(base::VirtualMemory* vm,
Address start, size_t commit_size,
size_t reserved_size) {
// Commit page header (not executable).
Address header = start;
size_t header_size = CodePageGuardStartOffset();
if (vm->Commit(header, header_size, false)) {
// Create guard page after the header.
if (vm->Guard(start + CodePageGuardStartOffset())) {
// Commit page body (executable).
Address body = start + CodePageAreaStartOffset();
size_t body_size = commit_size - CodePageGuardStartOffset();
if (vm->Commit(body, body_size, true)) {
// Create guard page before the end.
if (vm->Guard(start + reserved_size - CodePageGuardSize())) {
UpdateAllocatedSpaceLimits(start, start + CodePageAreaStartOffset() +
commit_size -
CodePageGuardStartOffset());
return true;
}
vm->Uncommit(body, body_size);
}
}
vm->Uncommit(header, header_size);
}
return false;
}
// -----------------------------------------------------------------------------
// MemoryChunk implementation
bool MemoryChunk::contains_array_buffers() {
return local_tracker() != nullptr && !local_tracker()->IsEmpty();
}
void MemoryChunk::ReleaseAllocatedMemory() {
if (skip_list_ != nullptr) {
delete skip_list_;
skip_list_ = nullptr;
}
if (mutex_ != nullptr) {
delete mutex_;
mutex_ = nullptr;
}
ReleaseSlotSet<OLD_TO_NEW>();
ReleaseSlotSet<OLD_TO_OLD>();
ReleaseTypedSlotSet<OLD_TO_NEW>();
ReleaseTypedSlotSet<OLD_TO_OLD>();
if (local_tracker_ != nullptr) ReleaseLocalTracker();
if (young_generation_bitmap_ != nullptr) ReleaseYoungGenerationBitmap();
}
static SlotSet* AllocateAndInitializeSlotSet(size_t size, Address page_start) {
size_t pages = (size + Page::kPageSize - 1) / Page::kPageSize;
DCHECK(pages > 0);
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());
if (!slot_set_[type].TrySetValue(nullptr, slot_set)) {
delete[] slot_set;
slot_set = slot_set_[type].Value();
DCHECK(slot_set);
return 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].Value();
if (slot_set) {
delete[] slot_set;
slot_set_[type].SetValue(nullptr);
}
}
template TypedSlotSet* MemoryChunk::AllocateTypedSlotSet<OLD_TO_NEW>();
template TypedSlotSet* MemoryChunk::AllocateTypedSlotSet<OLD_TO_OLD>();
template <RememberedSetType type>
TypedSlotSet* MemoryChunk::AllocateTypedSlotSet() {
TypedSlotSet* slot_set = new TypedSlotSet(address());
if (!typed_slot_set_[type].TrySetValue(nullptr, slot_set)) {
delete slot_set;
slot_set = typed_slot_set_[type].Value();
DCHECK(slot_set);
return slot_set;
}
return 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].Value();
if (typed_slot_set) {
delete typed_slot_set;
typed_slot_set_[type].SetValue(nullptr);
}
}
void MemoryChunk::AllocateLocalTracker() {
DCHECK_NULL(local_tracker_);
local_tracker_ = new LocalArrayBufferTracker(heap());
}
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
STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::NEW_SPACE) ==
ObjectSpace::kObjectSpaceNewSpace);
STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::OLD_SPACE) ==
ObjectSpace::kObjectSpaceOldSpace);
STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::CODE_SPACE) ==
ObjectSpace::kObjectSpaceCodeSpace);
STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::MAP_SPACE) ==
ObjectSpace::kObjectSpaceMapSpace);
void Space::AddAllocationObserver(AllocationObserver* observer) {
allocation_observers_->Add(observer);
}
void Space::RemoveAllocationObserver(AllocationObserver* observer) {
bool removed = allocation_observers_->RemoveElement(observer);
USE(removed);
DCHECK(removed);
}
void Space::PauseAllocationObservers() { allocation_observers_paused_ = true; }
void Space::ResumeAllocationObservers() {
allocation_observers_paused_ = false;
}
void Space::AllocationStep(Address soon_object, int size) {
if (!allocation_observers_paused_) {
for (int i = 0; i < allocation_observers_->length(); ++i) {
AllocationObserver* o = (*allocation_observers_)[i];
o->AllocationStep(size, soon_object, size);
}
}
}
PagedSpace::PagedSpace(Heap* heap, AllocationSpace space,
Executability executable)
: Space(heap, space, executable), anchor_(this), free_list_(this) {
area_size_ = MemoryAllocator::PageAreaSize(space);
accounting_stats_.Clear();
allocation_info_.Reset(nullptr, nullptr);
}
bool PagedSpace::SetUp() { return true; }
bool PagedSpace::HasBeenSetUp() { return true; }
void PagedSpace::TearDown() {
for (auto it = begin(); it != end();) {
Page* page = *(it++); // Will be erased.
ArrayBufferTracker::FreeAll(page);
heap()->memory_allocator()->Free<MemoryAllocator::kFull>(page);
}
anchor_.set_next_page(&anchor_);
anchor_.set_prev_page(&anchor_);
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) {
return;
}
MarkCompactCollector* collector = heap()->mark_compact_collector();
intptr_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() && (p->owner() != this)) {
base::LockGuard<base::Mutex> guard(
reinterpret_cast<PagedSpace*>(p->owner())->mutex());
p->Unlink();
p->set_owner(this);
p->InsertAfter(anchor_.prev_page());
}
added += RelinkFreeListCategories(p);
added += p->wasted_memory();
if (is_local() && (added > kCompactionMemoryWanted)) break;
}
}
accounting_stats_.IncreaseCapacity(added);
}
void PagedSpace::MergeCompactionSpace(CompactionSpace* other) {
DCHECK(identity() == other->identity());
// Unmerged fields:
// area_size_
// anchor_
other->EmptyAllocationInfo();
// Update and clear accounting statistics.
accounting_stats_.Merge(other->accounting_stats_);
other->accounting_stats_.Clear();
// The linear allocation area of {other} should be destroyed now.
DCHECK(other->top() == nullptr);
DCHECK(other->limit() == nullptr);
AccountCommitted(other->CommittedMemory());
// Move over pages.
for (auto it = other->begin(); it != other->end();) {
Page* p = *(it++);
// Relinking requires the category to be unlinked.
other->UnlinkFreeListCategories(p);
p->Unlink();
p->set_owner(this);
p->InsertAfter(anchor_.prev_page());
RelinkFreeListCategories(p);
DCHECK_EQ(p->AvailableInFreeList(), p->available_in_free_list());
}
}
size_t PagedSpace::CommittedPhysicalMemory() {
if (!base::VirtualMemory::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;
}
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) return nullptr;
AccountUncommitted(page->size());
accounting_stats_.DeallocateBytes(page->LiveBytesFromFreeList());
accounting_stats_.DecreaseCapacity(page->area_size());
page->Unlink();
UnlinkFreeListCategories(page);
return page;
}
void PagedSpace::AddPage(Page* page) {
AccountCommitted(page->size());
accounting_stats_.IncreaseCapacity(page->area_size());
accounting_stats_.AllocateBytes(page->LiveBytesFromFreeList());
page->set_owner(this);
RelinkFreeListCategories(page);
page->InsertAfter(anchor()->prev_page());
}
void PagedSpace::ShrinkImmortalImmovablePages() {
DCHECK(!heap()->deserialization_complete());
MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
EmptyAllocationInfo();
ResetFreeList();
for (Page* page : *this) {
DCHECK(page->IsFlagSet(Page::NEVER_EVACUATE));
size_t unused = page->ShrinkToHighWaterMark();
accounting_stats_.DecreaseCapacity(static_cast<intptr_t>(unused));
// Do not account for the unused space as uncommitted because the counter
// is kept in sync with page size which is also not adjusted for those
// chunks.
}
}
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* p = heap()->memory_allocator()->AllocatePage(size, this, executable());
if (p == nullptr) return false;
AccountCommitted(p->size());
// Pages created during bootstrapping may contain immortal immovable objects.
if (!heap()->deserialization_complete()) p->MarkNeverEvacuate();
DCHECK(Capacity() <= heap()->MaxOldGenerationSize());
p->InsertAfter(anchor_.prev_page());
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::SetAllocationInfo(Address top, Address limit) {
SetTopAndLimit(top, limit);
if (top != nullptr && top != limit &&
heap()->incremental_marking()->black_allocation()) {
Page::FromAllocationAreaAddress(top)->CreateBlackArea(top, limit);
}
}
void PagedSpace::MarkAllocationInfoBlack() {
DCHECK(heap()->incremental_marking()->black_allocation());
Address current_top = top();
Address current_limit = limit();
if (current_top != nullptr && current_top != current_limit) {
Page::FromAllocationAreaAddress(current_top)
->CreateBlackArea(current_top, current_limit);
}
}
void PagedSpace::UnmarkAllocationInfo() {
Address current_top = top();
Address current_limit = limit();
if (current_top != nullptr && current_top != current_limit) {
Page::FromAllocationAreaAddress(current_top)
->DestroyBlackArea(current_top, current_limit);
}
}
// Empty space allocation info, returning unused area to free list.
void PagedSpace::EmptyAllocationInfo() {
// 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 == nullptr) {
DCHECK(current_limit == nullptr);
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) {
MarkingState::Internal(page).bitmap()->ClearRange(
page->AddressToMarkbitIndex(current_top),
page->AddressToMarkbitIndex(current_limit));
MarkingState::Internal(page).IncrementLiveBytes(
-static_cast<int>(current_limit - current_top));
}
}
SetTopAndLimit(NULL, NULL);
DCHECK_GE(current_limit, current_top);
Free(current_top, current_limit - current_top);
}
void PagedSpace::IncreaseCapacity(size_t bytes) {
accounting_stats_.ExpandSpace(bytes);
}
void PagedSpace::ReleasePage(Page* page) {
DCHECK_EQ(0, MarkingState::Internal(page).live_bytes());
DCHECK_EQ(page->owner(), this);
free_list_.EvictFreeListItems(page);
DCHECK(!free_list_.ContainsPageFreeListItems(page));
if (Page::FromAllocationAreaAddress(allocation_info_.top()) == page) {
allocation_info_.Reset(nullptr, nullptr);
}
// If page is still in a list, unlink it from that list.
if (page->next_chunk() != NULL) {
DCHECK(page->prev_chunk() != NULL);
page->Unlink();
}
AccountUncommitted(page->size());
accounting_stats_.ShrinkSpace(page->area_size());
heap()->memory_allocator()->Free<MemoryAllocator::kPreFreeAndQueue>(page);
}
std::unique_ptr<ObjectIterator> PagedSpace::GetObjectIterator() {
return std::unique_ptr<ObjectIterator>(new HeapObjectIterator(this));
}
#ifdef DEBUG
void PagedSpace::Print() {}
#endif
#ifdef VERIFY_HEAP
void PagedSpace::Verify(ObjectVisitor* visitor) {
bool allocation_pointer_found_in_space =
(allocation_info_.top() == allocation_info_.limit());
for (Page* page : *this) {
CHECK(page->owner() == this);
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();
int black_size = 0;
for (HeapObject* object = it.Next(); object != 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(heap()->map_space()->Contains(map));
// Perform space-specific object verification.
VerifyObject(object);
// The object itself should look OK.
object->ObjectVerify();
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->instance_type(), size, visitor);
if (ObjectMarking::IsBlack(object, MarkingState::Internal(object))) {
black_size += size;
}
CHECK(object->address() + size <= top);
end_of_previous_object = object->address() + size;
}
CHECK_LE(black_size, MarkingState::Internal(page).live_bytes());
}
CHECK(allocation_pointer_found_in_space);
}
#endif // VERIFY_HEAP
// -----------------------------------------------------------------------------
// NewSpace implementation
bool NewSpace::SetUp(size_t initial_semispace_capacity,
size_t maximum_semispace_capacity) {
DCHECK(initial_semispace_capacity <= maximum_semispace_capacity);
DCHECK(base::bits::IsPowerOfTwo32(
static_cast<uint32_t>(maximum_semispace_capacity)));
to_space_.SetUp(initial_semispace_capacity, maximum_semispace_capacity);
from_space_.SetUp(initial_semispace_capacity, maximum_semispace_capacity);
if (!to_space_.Commit()) {
return false;
}
DCHECK(!from_space_.is_committed()); // No need to use memory yet.
ResetAllocationInfo();
// Allocate and set up the histogram arrays if necessary.
allocated_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
promoted_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
#define SET_NAME(name) \
allocated_histogram_[name].set_name(#name); \
promoted_histogram_[name].set_name(#name);
INSTANCE_TYPE_LIST(SET_NAME)
#undef SET_NAME
return true;
}
void NewSpace::TearDown() {
if (allocated_histogram_) {
DeleteArray(allocated_histogram_);
allocated_histogram_ = NULL;
}
if (promoted_histogram_) {
DeleteArray(promoted_histogram_);
promoted_histogram_ = NULL;
}
allocation_info_.Reset(nullptr, nullptr);
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.
CHECK(false);
}
}
}
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.
CHECK(false);
}
}
}
DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
}
bool NewSpace::Rebalance() {
CHECK(heap()->promotion_queue()->is_empty());
// 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);
int actual_pages = 0;
Page* current_page = anchor()->next_page();
while (current_page != anchor()) {
actual_pages++;
current_page = current_page->next_page();
if (actual_pages > expected_pages) {
Page* to_remove = current_page->prev_page();
// Make sure we don't overtake the actual top pointer.
CHECK_NE(to_remove, current_page_);
to_remove->Unlink();
// Clear new space flags to avoid this page being treated as a new
// space page that is potentially being swept.
to_remove->SetFlags(0, Page::kIsInNewSpaceMask);
heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(
to_remove);
}
}
while (actual_pages < expected_pages) {
actual_pages++;
current_page =
heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>(
Page::kAllocatableMemory, this, executable());
if (current_page == nullptr) return false;
DCHECK_NOT_NULL(current_page);
current_page->InsertAfter(anchor());
MarkingState::Internal(current_page).ClearLiveness();
current_page->SetFlags(anchor()->prev_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;
}
AllocationInfo LocalAllocationBuffer::Close() {
if (IsValid()) {
heap_->CreateFillerObjectAt(
allocation_info_.top(),
static_cast<int>(allocation_info_.limit() - allocation_info_.top()),
ClearRecordedSlots::kNo);
const AllocationInfo old_info = allocation_info_;
allocation_info_ = AllocationInfo(nullptr, nullptr);
return old_info;
}
return AllocationInfo(nullptr, nullptr);
}
LocalAllocationBuffer::LocalAllocationBuffer(Heap* heap,
AllocationInfo 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(nullptr, nullptr);
return *this;
}
void NewSpace::UpdateAllocationInfo() {
MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
allocation_info_.Reset(to_space_.page_low(), to_space_.page_high());
UpdateInlineAllocationLimit(0);
DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
}
void NewSpace::ResetAllocationInfo() {
Address old_top = allocation_info_.top();
to_space_.Reset();
UpdateAllocationInfo();
// Clear all mark-bits in the to-space.
for (Page* p : to_space_) {
MarkingState::Internal(p).ClearLiveness();
}
InlineAllocationStep(old_top, allocation_info_.top(), nullptr, 0);
}
void NewSpace::UpdateInlineAllocationLimit(int size_in_bytes) {
if (heap()->inline_allocation_disabled()) {
// Lowest limit when linear allocation was disabled.
Address high = to_space_.page_high();
Address new_top = allocation_info_.top() + size_in_bytes;
allocation_info_.set_limit(Min(new_top, high));
} else if (allocation_observers_paused_ || top_on_previous_step_ == 0) {
// Normal limit is the end of the current page.
allocation_info_.set_limit(to_space_.page_high());
} else {
// Lower limit during incremental marking.
Address high = to_space_.page_high();
Address new_top = allocation_info_.top() + size_in_bytes;
Address new_limit = new_top + GetNextInlineAllocationStepSize() - 1;
allocation_info_.set_limit(Min(new_limit, high));
}
DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
}
bool NewSpace::AddFreshPage() {
Address top = allocation_info_.top();
DCHECK(!Page::IsAtObjectStart(top));
if (!to_space_.AdvancePage()) {
// No more pages left to advance.
return false;
}
// Clear remainder of current page.
Address limit = Page::FromAllocationAreaAddress(top)->area_end();
if (heap()->gc_state() == Heap::SCAVENGE) {
heap()->promotion_queue()->SetNewLimit(limit);
}
int remaining_in_page = static_cast<int>(limit - top);
heap()->CreateFillerObjectAt(top, remaining_in_page, ClearRecordedSlots::kNo);
UpdateAllocationInfo();
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;
}
InlineAllocationStep(old_top, allocation_info_.top(), nullptr, 0);
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;
}
void NewSpace::StartNextInlineAllocationStep() {
if (!allocation_observers_paused_) {
top_on_previous_step_ =
allocation_observers_->length() ? allocation_info_.top() : 0;
UpdateInlineAllocationLimit(0);
}
}
intptr_t NewSpace::GetNextInlineAllocationStepSize() {
intptr_t next_step = 0;
for (int i = 0; i < allocation_observers_->length(); ++i) {
AllocationObserver* o = (*allocation_observers_)[i];
next_step = next_step ? Min(next_step, o->bytes_to_next_step())
: o->bytes_to_next_step();
}
DCHECK(allocation_observers_->length() == 0 || next_step != 0);
return next_step;
}
void NewSpace::AddAllocationObserver(AllocationObserver* observer) {
Space::AddAllocationObserver(observer);
StartNextInlineAllocationStep();
}
void NewSpace::RemoveAllocationObserver(AllocationObserver* observer) {
Space::RemoveAllocationObserver(observer);
StartNextInlineAllocationStep();
}
void NewSpace::PauseAllocationObservers() {
// Do a step to account for memory allocated so far.
InlineAllocationStep(top(), top(), nullptr, 0);
Space::PauseAllocationObservers();
top_on_previous_step_ = 0;
UpdateInlineAllocationLimit(0);
}
void NewSpace::ResumeAllocationObservers() {
DCHECK(top_on_previous_step_ == 0);
Space::ResumeAllocationObservers();
StartNextInlineAllocationStep();
}
void NewSpace::InlineAllocationStep(Address top, Address new_top,
Address soon_object, size_t size) {
if (top_on_previous_step_) {
int bytes_allocated = static_cast<int>(top - top_on_previous_step_);
for (int i = 0; i < allocation_observers_->length(); ++i) {
(*allocation_observers_)[i]->AllocationStep(bytes_allocated, soon_object,
size);
}
top_on_previous_step_ = new_top;
}
}
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() {
// 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());
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.
Map* map = object->map();
CHECK(map->IsMap());
CHECK(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();
// All the interior pointers should be contained in the heap.
VerifyPointersVisitor visitor;
int size = object->Size();
object->IterateBody(map->instance_type(), size, &visitor);
current += size;
} else {
// At end of page, switch to next page.
Page* page = Page::FromAllocationAreaAddress(current)->next_page();
// Next page should be valid.
CHECK(!page->is_anchor());
current = page->area_start();
}
}
// 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()) {
for (Page* p : *this) {
ArrayBufferTracker::FreeAll(p);
}
Uncommit();
}
current_capacity_ = maximum_capacity_ = 0;
}
bool SemiSpace::Commit() {
DCHECK(!is_committed());
Page* current = anchor();
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, executable());
if (new_page == nullptr) {
RewindPages(current, pages_added);
return false;
}
new_page->InsertAfter(current);
current = new_page;
}
Reset();
AccountCommitted(current_capacity_);
if (age_mark_ == nullptr) {
age_mark_ = first_page()->area_start();
}
committed_ = true;
return true;
}
bool SemiSpace::Uncommit() {
DCHECK(is_committed());
for (auto it = begin(); it != end();) {
Page* p = *(it++);
heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(p);
}
anchor()->set_next_page(anchor());
anchor()->set_prev_page(anchor());
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 & Page::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, base::OS::AllocateAlignment()));
const int delta_pages = static_cast<int>(delta / Page::kPageSize);
Page* last_page = anchor()->prev_page();
DCHECK_NE(last_page, anchor());
for (int pages_added = 0; pages_added < delta_pages; pages_added++) {
Page* new_page =
heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>(
Page::kAllocatableMemory, this, executable());
if (new_page == nullptr) {
RewindPages(last_page, pages_added);
return false;
}
new_page->InsertAfter(last_page);
MarkingState::Internal(new_page).ClearLiveness();
// Duplicate the flags that was set on the old page.
new_page->SetFlags(last_page->GetFlags(), Page::kCopyOnFlipFlagsMask);
last_page = new_page;
}
AccountCommitted(delta);
current_capacity_ = new_capacity;
return true;
}
void SemiSpace::RewindPages(Page* start, int num_pages) {
Page* new_last_page = nullptr;
Page* last_page = start;
while (num_pages > 0) {
DCHECK_NE(last_page, anchor());
new_last_page = last_page->prev_page();
last_page->prev_page()->set_next_page(last_page->next_page());
last_page->next_page()->set_prev_page(last_page->prev_page());
last_page = new_last_page;
num_pages--;
}
}
bool SemiSpace::ShrinkTo(size_t new_capacity) {
DCHECK_EQ(new_capacity & Page::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, base::OS::AllocateAlignment()));
int delta_pages = static_cast<int>(delta / Page::kPageSize);
Page* new_last_page;
Page* last_page;
while (delta_pages > 0) {
last_page = anchor()->prev_page();
new_last_page = last_page->prev_page();
new_last_page->set_next_page(anchor());
anchor()->set_prev_page(new_last_page);
heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(
last_page);
delta_pages--;
}
AccountUncommitted(delta);
heap()->memory_allocator()->unmapper()->FreeQueuedChunks();
}
current_capacity_ = new_capacity;
return true;
}
void SemiSpace::FixPagesFlags(intptr_t flags, intptr_t mask) {
anchor_.set_owner(this);
anchor_.prev_page()->set_next_page(&anchor_);
anchor_.next_page()->set_prev_page(&anchor_);
for (Page* page : *this) {
page->set_owner(this);
page->SetFlags(flags, mask);
if (id_ == kToSpace) {
page->ClearFlag(MemoryChunk::IN_FROM_SPACE);
page->SetFlag(MemoryChunk::IN_TO_SPACE);
page->ClearFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK);
MarkingState::Internal(page).SetLiveBytes(0);
} else {
page->SetFlag(MemoryChunk::IN_FROM_SPACE);
page->ClearFlag(MemoryChunk::IN_TO_SPACE);
}
DCHECK(page->IsFlagSet(MemoryChunk::IN_TO_SPACE) ||
page->IsFlagSet(MemoryChunk::IN_FROM_SPACE));
}
}
void SemiSpace::Reset() {
DCHECK_NE(anchor_.next_page(), &anchor_);
current_page_ = anchor_.next_page();
pages_used_ = 0;
}
void SemiSpace::RemovePage(Page* page) {
if (current_page_ == page) {
current_page_ = page->prev_page();
}
page->Unlink();
}
void SemiSpace::PrependPage(Page* page) {
page->SetFlags(current_page()->GetFlags(),
static_cast<uintptr_t>(Page::kCopyAllFlags));
page->set_owner(this);
page->InsertAfter(anchor());
pages_used_++;
}
void SemiSpace::Swap(SemiSpace* from, SemiSpace* to) {
// We won't be swapping semispaces without data in them.
DCHECK_NE(from->anchor_.next_page(), &from->anchor_);
DCHECK_NE(to->anchor_.next_page(), &to->anchor_);
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->anchor_, to->anchor_);
std::swap(from->current_page_, to->current_page_);
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);
Page* page = anchor_.next_page();
CHECK(anchor_.owner() == this);
while (page != &anchor_) {
CHECK_EQ(page->owner(), this);
CHECK(page->InNewSpace());
CHECK(page->IsFlagSet(is_from_space ? MemoryChunk::IN_FROM_SPACE
: MemoryChunk::IN_TO_SPACE));
CHECK(!page->IsFlagSet(is_from_space ? MemoryChunk::IN_TO_SPACE
: MemoryChunk::IN_FROM_SPACE));
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));
}
// TODO(gc): Check that the live_bytes_count_ field matches the
// black marking on the page (if we make it match in new-space).
}
CHECK_EQ(page->prev_page()->next_page(), page);
page = page->next_page();
}
}
#endif
#ifdef DEBUG
void SemiSpace::AssertValidRange(Address start, Address end) {
// Addresses belong to same semi-space
Page* page = Page::FromAllocationAreaAddress(start);
Page* end_page = Page::FromAllocationAreaAddress(end);
SemiSpace* space = reinterpret_cast<SemiSpace*>(page->owner());
CHECK_EQ(space, end_page->owner());
// Start address is before end address, either on same page,
// or end address is on a later page in the linked list of
// semi-space pages.
if (page == end_page) {
CHECK_LE(start, end);
} else {
while (page != end_page) {
page = page->next_page();
CHECK_NE(page, space->anchor());
}
}
}
#endif
// -----------------------------------------------------------------------------
// SemiSpaceIterator implementation.
SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) {
Initialize(space->bottom(), space->top());
}
void SemiSpaceIterator::Initialize(Address start, Address end) {
SemiSpace::AssertValidRange(start, end);
current_ = start;
limit_ = end;
}
#ifdef DEBUG
// heap_histograms is shared, always clear it before using it.
static void ClearHistograms(Isolate* isolate) {
// We reset the name each time, though it hasn't changed.
#define DEF_TYPE_NAME(name) isolate->heap_histograms()[name].set_name(#name);
INSTANCE_TYPE_LIST(DEF_TYPE_NAME)
#undef DEF_TYPE_NAME
#define CLEAR_HISTOGRAM(name) isolate->heap_histograms()[name].clear();
INSTANCE_TYPE_LIST(CLEAR_HISTOGRAM)
#undef CLEAR_HISTOGRAM
isolate->js_spill_information()->Clear();
}
static int CollectHistogramInfo(HeapObject* obj) {
Isolate* isolate = obj->GetIsolate();
InstanceType type = obj->map()->instance_type();
DCHECK(0 <= type && type <= LAST_TYPE);
DCHECK(isolate->heap_histograms()[type].name() != NULL);
isolate->heap_histograms()[type].increment_number(1);
isolate->heap_histograms()[type].increment_bytes(obj->Size());
if (FLAG_collect_heap_spill_statistics && obj->IsJSObject()) {
JSObject::cast(obj)
->IncrementSpillStatistics(isolate->js_spill_information());
}
return obj->Size();
}
static void ReportHistogram(Isolate* isolate, bool print_spill) {
PrintF("\n Object Histogram:\n");
for (int i = 0; i <= LAST_TYPE; i++) {
if (isolate->heap_histograms()[i].number() > 0) {
PrintF(" %-34s%10d (%10d bytes)\n",
isolate->heap_histograms()[i].name(),
isolate->heap_histograms()[i].number(),
isolate->heap_histograms()[i].bytes());
}
}
PrintF("\n");
// Summarize string types.
int string_number = 0;
int string_bytes = 0;
#define INCREMENT(type, size, name, camel_name) \
string_number += isolate->heap_histograms()[type].number(); \
string_bytes += isolate->heap_histograms()[type].bytes();
STRING_TYPE_LIST(INCREMENT)
#undef INCREMENT
if (string_number > 0) {
PrintF(" %-34s%10d (%10d bytes)\n\n", "STRING_TYPE", string_number,
string_bytes);
}
if (FLAG_collect_heap_spill_statistics && print_spill) {
isolate->js_spill_information()->Print();
}
}
#endif // DEBUG
// Support for statistics gathering for --heap-stats and --log-gc.
void NewSpace::ClearHistograms() {
for (int i = 0; i <= LAST_TYPE; i++) {
allocated_histogram_[i].clear();
promoted_histogram_[i].clear();
}
}
// Because the copying collector does not touch garbage objects, we iterate
// the new space before a collection to get a histogram of allocated objects.
// This only happens when --log-gc flag is set.
void NewSpace::CollectStatistics() {
ClearHistograms();
SemiSpaceIterator it(this);
for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next())
RecordAllocation(obj);
}
static void DoReportStatistics(Isolate* isolate, HistogramInfo* info,
const char* description) {
LOG(isolate, HeapSampleBeginEvent("NewSpace", description));
// Lump all the string types together.
int string_number = 0;
int string_bytes = 0;
#define INCREMENT(type, size, name, camel_name) \
string_number += info[type].number(); \
string_bytes += info[type].bytes();
STRING_TYPE_LIST(INCREMENT)
#undef INCREMENT
if (string_number > 0) {
LOG(isolate,
HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes));
}
// Then do the other types.
for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) {
if (info[i].number() > 0) {
LOG(isolate, HeapSampleItemEvent(info[i].name(), info[i].number(),
info[i].bytes()));
}
}
LOG(isolate, HeapSampleEndEvent("NewSpace", description));
}
void NewSpace::ReportStatistics() {
#ifdef DEBUG
if (FLAG_heap_stats) {
float pct = static_cast<float>(Available()) / TotalCapacity();
PrintF(" capacity: %" PRIuS ", available: %" PRIuS ", %%%d\n",
TotalCapacity(), Available(), static_cast<int>(pct * 100));
PrintF("\n Object Histogram:\n");
for (int i = 0; i <= LAST_TYPE; i++) {
if (allocated_histogram_[i].number() > 0) {
PrintF(" %-34s%10d (%10d bytes)\n", allocated_histogram_[i].name(),
allocated_histogram_[i].number(),
allocated_histogram_[i].bytes());
}
}
PrintF("\n");
}
#endif // DEBUG
if (FLAG_log_gc) {
Isolate* isolate = heap()->isolate();
DoReportStatistics(isolate, allocated_histogram_, "allocated");
DoReportStatistics(isolate, promoted_histogram_, "promoted");
}
}
void NewSpace::RecordAllocation(HeapObject* obj) {
InstanceType type = obj->map()->instance_type();
DCHECK(0 <= type && type <= LAST_TYPE);
allocated_histogram_[type].increment_number(1);
allocated_histogram_[type].increment_bytes(obj->Size());
}
void NewSpace::RecordPromotion(HeapObject* obj) {
InstanceType type = obj->map()->instance_type();
DCHECK(0 <= type && type <= LAST_TYPE);
promoted_histogram_[type].increment_number(1);
promoted_histogram_[type].increment_bytes(obj->Size());
}
size_t NewSpace::CommittedPhysicalMemory() {
if (!base::VirtualMemory::HasLazyCommits()) return CommittedMemory();
MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
size_t size = to_space_.CommittedPhysicalMemory();
if (from_space_.is_committed()) {
size += from_space_.CommittedPhysicalMemory();
}
return size;
}
// -----------------------------------------------------------------------------
// Free lists for old object spaces implementation
void FreeListCategory::Reset() {
set_top(nullptr);
set_prev(nullptr);
set_next(nullptr);
available_ = 0;
}
FreeSpace* FreeListCategory::PickNodeFromList(size_t* node_size) {
DCHECK(page()->CanAllocate());
FreeSpace* node = top();
if (node == nullptr) return nullptr;
set_top(node->next());
*node_size = node->Size();
available_ -= *node_size;
return node;
}
FreeSpace* FreeListCategory::TryPickNodeFromList(size_t minimum_size,
size_t* node_size) {
DCHECK(page()->CanAllocate());
FreeSpace* node = PickNodeFromList(node_size);
if ((node != nullptr) && (*node_size < minimum_size)) {
Free(node, *node_size, kLinkCategory);
*node_size = 0;
return nullptr;
}
return node;
}
FreeSpace* FreeListCategory::SearchForNodeInList(size_t minimum_size,
size_t* node_size) {
DCHECK(page()->CanAllocate());
FreeSpace* prev_non_evac_node = nullptr;
for (FreeSpace* cur_node = top(); cur_node != nullptr;
cur_node = cur_node->next()) {
size_t size = cur_node->size();
if (size >= minimum_size) {
DCHECK_GE(available_, size);
available_ -= size;
if (cur_node == top()) {
set_top(cur_node->next());
}
if (prev_non_evac_node != nullptr) {
prev_non_evac_node->set_next(cur_node->next());
}
*node_size = size;
return cur_node;
}
prev_non_evac_node = cur_node;
}
return nullptr;
}
bool FreeListCategory::Free(FreeSpace* free_space, size_t size_in_bytes,
FreeMode mode) {
if (!page()->CanAllocate()) return false;
free_space->set_next(top());
set_top(free_space);
available_ += size_in_bytes;
if ((mode == kLinkCategory) && (prev() == nullptr) && (next() == nullptr)) {
owner()->AddCategory(this);
}
return true;
}
void FreeListCategory::RepairFreeList(Heap* heap) {
FreeSpace* n = top();
while (n != NULL) {
Map** map_location = reinterpret_cast<Map**>(n->address());
if (*map_location == NULL) {
*map_location = heap->free_space_map();
} else {
DCHECK(*map_location == heap->free_space_map());
}
n = n->next();
}
}
void FreeListCategory::Relink() {
DCHECK(!is_linked());
owner()->AddCategory(this);
}
void FreeListCategory::Invalidate() {
page()->remove_available_in_free_list(available());
Reset();
type_ = kInvalidCategory;
}
FreeList::FreeList(PagedSpace* owner) : owner_(owner), wasted_bytes_(0) {
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
categories_[i] = nullptr;
}
Reset();
}
void FreeList::Reset() {
ForAllFreeListCategories(
[](FreeListCategory* category) { category->Reset(); });
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
categories_[i] = nullptr;
}
ResetStats();
}
size_t FreeList::Free(Address start, size_t size_in_bytes, FreeMode mode) {
if (size_in_bytes == 0) return 0;
owner()->heap()->CreateFillerObjectAt(start, static_cast<int>(size_in_bytes),
ClearRecordedSlots::kNo);
Page* page = Page::FromAddress(start);
// Blocks have to be a minimum size to hold free list items.
if (size_in_bytes < kMinBlockSize) {
page->add_wasted_memory(size_in_bytes);
wasted_bytes_.Increment(size_in_bytes);
return size_in_bytes;
}
FreeSpace* free_space = FreeSpace::cast(HeapObject::FromAddress(start));
// Insert other blocks at the head of a free list of the appropriate
// magnitude.
FreeListCategoryType type = SelectFreeListCategoryType(size_in_bytes);
if (page->free_list_category(type)->Free(free_space, size_in_bytes, mode)) {
page->add_available_in_free_list(size_in_bytes);
}
DCHECK_EQ(page->AvailableInFreeList(), page->available_in_free_list());
return 0;
}
FreeSpace* FreeList::FindNodeIn(FreeListCategoryType type, size_t* node_size) {
FreeListCategoryIterator it(this, type);
FreeSpace* node = nullptr;
while (it.HasNext()) {
FreeListCategory* current = it.Next();
node = current->PickNodeFromList(node_size);
if (node != nullptr) {
Page::FromAddress(node->address())
->remove_available_in_free_list(*node_size);
DCHECK(IsVeryLong() || Available() == SumFreeLists());
return node;
}
RemoveCategory(current);
}
return node;
}
FreeSpace* FreeList::TryFindNodeIn(FreeListCategoryType type, size_t* node_size,
size_t minimum_size) {
if (categories_[type] == nullptr) return nullptr;
FreeSpace* node =
categories_[type]->TryPickNodeFromList(minimum_size, node_size);
if (node != nullptr) {
Page::FromAddress(node->address())
->remove_available_in_free_list(*node_size);
DCHECK(IsVeryLong() || Available() == SumFreeLists());
}
return node;
}
FreeSpace* FreeList::SearchForNodeInList(FreeListCategoryType type,
size_t* node_size,
size_t minimum_size) {
FreeListCategoryIterator it(this, type);
FreeSpace* node = nullptr;
while (it.HasNext()) {
FreeListCategory* current = it.Next();
node = current->SearchForNodeInList(minimum_size, node_size);
if (node != nullptr) {
Page::FromAddress(node->address())
->remove_available_in_free_list(*node_size);
DCHECK(IsVeryLong() || Available() == SumFreeLists());
return node;
}
if (current->is_empty()) {
RemoveCategory(current);
}
}
return node;
}
FreeSpace* FreeList::FindNodeFor(size_t size_in_bytes, size_t* node_size) {
FreeSpace* node = nullptr;
// First try the allocation fast path: try to allocate the minimum element
// size of a free list category. This operation is constant time.
FreeListCategoryType type =
SelectFastAllocationFreeListCategoryType(size_in_bytes);
for (int i = type; i < kHuge; i++) {
node = FindNodeIn(static_cast<FreeListCategoryType>(i), node_size);
if (node != nullptr) return node;
}
// Next search the huge list for free list nodes. This takes linear time in
// the number of huge elements.
node = SearchForNodeInList(kHuge, node_size, size_in_bytes);
if (node != nullptr) {
DCHECK(IsVeryLong() || Available() == SumFreeLists());
return node;
}
// We need a huge block of memory, but we didn't find anything in the huge
// list.
if (type == kHuge) return nullptr;
// Now search the best fitting free list for a node that has at least the
// requested size.
type = SelectFreeListCategoryType(size_in_bytes);
node = TryFindNodeIn(type, node_size, size_in_bytes);
DCHECK(IsVeryLong() || Available() == SumFreeLists());
return node;
}
// Allocation on the old space free list. If it succeeds then a new linear
// allocation space has been set up with the top and limit of the space. If
// the allocation fails then NULL is returned, and the caller can perform a GC
// or allocate a new page before retrying.
HeapObject* FreeList::Allocate(size_t size_in_bytes) {
DCHECK(size_in_bytes <= kMaxBlockSize);
DCHECK(IsAligned(size_in_bytes, kPointerSize));
DCHECK_LE(owner_->top(), owner_->limit());
#ifdef DEBUG
if (owner_->top() != owner_->limit()) {
DCHECK_EQ(Page::FromAddress(owner_->top()),
Page::FromAddress(owner_->limit() - 1));
}
#endif
// Don't free list allocate if there is linear space available.
DCHECK_LT(static_cast<size_t>(owner_->limit() - owner_->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.
owner_->EmptyAllocationInfo();
owner_->heap()->StartIncrementalMarkingIfAllocationLimitIsReached(
Heap::kNoGCFlags, kNoGCCallbackFlags);
size_t new_node_size = 0;
FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
if (new_node == nullptr) return nullptr;
DCHECK_GE(new_node_size, size_in_bytes);
size_t bytes_left = new_node_size - size_in_bytes;
#ifdef DEBUG
for (size_t i = 0; i < size_in_bytes / kPointerSize; i++) {
reinterpret_cast<Object**>(new_node->address())[i] =
Smi::FromInt(kCodeZapValue);
}
#endif
// 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));
const size_t kThreshold = IncrementalMarking::kAllocatedThreshold;
// Memory in the linear allocation area is counted as allocated. We may free
// a little of this again immediately - see below.
owner_->AccountAllocatedBytes(new_node_size);
if (owner_->heap()->inline_allocation_disabled()) {
// Keep the linear allocation area empty if requested to do so, just
// return area back to the free list instead.
owner_->Free(new_node->address() + size_in_bytes, bytes_left);
owner_->SetAllocationInfo(new_node->address() + size_in_bytes,
new_node->address() + size_in_bytes);
} else if (bytes_left > kThreshold &&
owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
FLAG_incremental_marking) {
size_t linear_size = owner_->RoundSizeDownToObjectAlignment(kThreshold);
// We don't want to give too large linear areas to the allocator while
// incremental marking is going on, because we won't check again whether
// we want to do another increment until the linear area is used up.
DCHECK_GE(new_node_size, size_in_bytes + linear_size);
owner_->Free(new_node->address() + size_in_bytes + linear_size,
new_node_size - size_in_bytes - linear_size);
owner_->SetAllocationInfo(
new_node->address() + size_in_bytes,
new_node->address() + size_in_bytes + linear_size);
} else {
// Normally we give the rest of the node to the allocator as its new
// linear allocation area.
owner_->SetAllocationInfo(new_node->address() + size_in_bytes,
new_node->address() + new_node_size);
}
return new_node;
}
size_t FreeList::EvictFreeListItems(Page* page) {
size_t sum = 0;
page->ForAllFreeListCategories(
[this, &sum](FreeListCategory* category) {
DCHECK_EQ(this, category->owner());
sum += category->available();
RemoveCategory(category);
category->Invalidate();
});
return sum;
}
bool FreeList::ContainsPageFreeListItems(Page* page) {
bool contained = false;
page->ForAllFreeListCategories(
[this, &contained](FreeListCategory* category) {
if (category->owner() == this && category->is_linked()) {
contained = true;
}
});
return contained;
}
void FreeList::RepairLists(Heap* heap) {
ForAllFreeListCategories(
[heap](FreeListCategory* category) { category->RepairFreeList(heap); });
}
bool FreeList::AddCategory(FreeListCategory* category) {
FreeListCategoryType type = category->type_;
FreeListCategory* top = categories_[type];
if (category->is_empty()) return false;
if (top == category) return false;
// Common double-linked list insertion.
if (top != nullptr) {
top->set_prev(category);
}
category->set_next(top);
categories_[type] = category;
return true;
}
void FreeList::RemoveCategory(FreeListCategory* category) {
FreeListCategoryType type = category->type_;
FreeListCategory* top = categories_[type];
// Common double-linked list removal.
if (top == category) {
categories_[type] = category->next();
}
if (category->prev() != nullptr) {
category->prev()->set_next(category->next());
}
if (category->next() != nullptr) {
category->next()->set_prev(category->prev());
}
category->set_next(nullptr);
category->set_prev(nullptr);
}
void FreeList::PrintCategories(FreeListCategoryType type) {
FreeListCategoryIterator it(this, type);
PrintF("FreeList[%p, top=%p, %d] ", static_cast<void*>(this),
static_cast<void*>(categories_[type]), type);
while (it.HasNext()) {
FreeListCategory* current = it.Next();
PrintF("%p -> ", static_cast<void*>(current));
}
PrintF("null\n");
}
#ifdef DEBUG
size_t FreeListCategory::SumFreeList() {
size_t sum = 0;
FreeSpace* cur = top();
while (cur != NULL) {
DCHECK(cur->map() == cur->GetHeap()->root(Heap::kFreeSpaceMapRootIndex));
sum += cur->nobarrier_size();
cur = cur->next();
}
return sum;
}
int FreeListCategory::FreeListLength() {
int length = 0;
FreeSpace* cur = top();
while (cur != NULL) {
length++;
cur = cur->next();
if (length == kVeryLongFreeList) return length;
}
return length;
}
bool FreeList::IsVeryLong() {
int len = 0;
for (int i = kFirstCategory; i < kNumberOfCategories; i++) {
FreeListCategoryIterator it(this, static_cast<FreeListCategoryType>(i));
while (it.HasNext()) {
len += it.Next()->FreeListLength();
if (len >= FreeListCategory::kVeryLongFreeList) return true;
}
}
return false;
}
// This can take a very long time because it is linear in the number of entries
// on the free list, so it should not be called if FreeListLength returns
// kVeryLongFreeList.
size_t FreeList::SumFreeLists() {
size_t sum = 0;
ForAllFreeListCategories(
[&sum](FreeListCategory* category) { sum += category->SumFreeList(); });
return sum;
}
#endif
// -----------------------------------------------------------------------------
// OldSpace implementation
void PagedSpace::PrepareForMarkCompact() {
// We don't have a linear allocation area while sweeping. It will be restored
// on the first allocation after the sweep.
EmptyAllocationInfo();
// Clear the free list before a full GC---it will be rebuilt afterward.
free_list_.Reset();
}
size_t PagedSpace::SizeOfObjects() {
CHECK_GE(limit(), top());
DCHECK_GE(Size(), static_cast<size_t>(limit() - top()));
return Size() - (limit() - top());
}
// After we have booted, we have created a map which represents free space
// on the heap. If there was already a free list then the elements on it
// were created with the wrong FreeSpaceMap (normally NULL), so we need to
// fix them.
void PagedSpace::RepairFreeListsAfterDeserialization() {
free_list_.RepairLists(heap());
// Each page may have a small free space that is not tracked by a free list.
// Those free spaces still contain null as their map pointer.
// Overwrite them with new fillers.
for (Page* page : *this) {
int size = static_cast<int>(page->wasted_memory());
if (size == 0) {
// If there is no wasted memory then all free space is in the free list.
continue;
}
Address start = page->HighWaterMark();
Address end = page->area_end();
CHECK_EQ(size, static_cast<int>(end - start));
heap()->CreateFillerObjectAt(start, size, ClearRecordedSlots::kNo);
}
}
HeapObject* PagedSpace::SweepAndRetryAllocation(int size_in_bytes) {
MarkCompactCollector* collector = heap()->mark_compact_collector();
if (collector->sweeping_in_progress()) {
// Wait for the sweeper threads here and complete the sweeping phase.
collector->EnsureSweepingCompleted();
// After waiting for the sweeper threads, there may be new free-list
// entries.
return free_list_.Allocate(size_in_bytes);
}
return nullptr;
}
HeapObject* CompactionSpace::SweepAndRetryAllocation(int size_in_bytes) {
MarkCompactCollector* collector = heap()->mark_compact_collector();
if (collector->sweeping_in_progress()) {
collector->SweepAndRefill(this);
return free_list_.Allocate(size_in_bytes);
}
return nullptr;
}
HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
VMState<GC> state(heap()->isolate());
RuntimeCallTimerScope runtime_timer(heap()->isolate(),
&RuntimeCallStats::GC_SlowAllocateRaw);
return RawSlowAllocateRaw(size_in_bytes);
}
HeapObject* CompactionSpace::SlowAllocateRaw(int size_in_bytes) {
return RawSlowAllocateRaw(size_in_bytes);
}
HeapObject* PagedSpace::RawSlowAllocateRaw(int size_in_bytes) {
// Allocation in this space has failed.
DCHECK_GE(size_in_bytes, 0);
const int kMaxPagesToSweep = 1;
MarkCompactCollector* collector = heap()->mark_compact_collector();
// Sweeping is still in progress.
if (collector->sweeping_in_progress()) {
if (FLAG_concurrent_sweeping && !is_local() &&
!collector->sweeper().AreSweeperTasksRunning()) {
collector->EnsureSweepingCompleted();
}
// First try to refill the free-list, concurrent sweeper threads
// may have freed some objects in the meantime.
RefillFreeList();
// Retry the free list allocation.
HeapObject* object =
free_list_.Allocate(static_cast<size_t>(size_in_bytes));
if (object != NULL) return object;
// If sweeping is still in progress try to sweep pages on the main thread.
int max_freed = collector->sweeper().ParallelSweepSpace(
identity(), size_in_bytes, kMaxPagesToSweep);
RefillFreeList();
if (max_freed >= size_in_bytes) {
object = free_list_.Allocate(static_cast<size_t>(size_in_bytes));
if (object != nullptr) return object;
}
} else if (is_local()) {
// Sweeping not in progress and we are on a {CompactionSpace}. This can
// only happen when we are evacuating for the young generation.
PagedSpace* main_space = heap()->paged_space(identity());
Page* page = main_space->RemovePageSafe(size_in_bytes);
if (page != nullptr) {
AddPage(page);
HeapObject* object =
free_list_.Allocate(static_cast<size_t>(size_in_bytes));
if (object != nullptr) return object;
}
}
if (heap()->ShouldExpandOldGenerationOnSlowAllocation() && Expand()) {
DCHECK((CountTotalPages() > 1) ||
(static_cast<size_t>(size_in_bytes) <= free_list_.Available()));
return free_list_.Allocate(static_cast<size_t>(size_in_bytes));
}
// If sweeper threads are active, wait for them at that point and steal
// elements form their free-lists. Allocation may still fail their which
// would indicate that there is not enough memory for the given allocation.
return SweepAndRetryAllocation(size_in_bytes);
}
#ifdef DEBUG
void PagedSpace::ReportStatistics() {
int pct = static_cast<int>(Available() * 100 / Capacity());
PrintF(" capacity: %" PRIuS ", waste: %" PRIuS
", available: %" PRIuS ", %%%d\n",
Capacity(), Waste(), Available(), pct);
heap()->mark_compact_collector()->EnsureSweepingCompleted();
ClearHistograms(heap()->isolate());
HeapObjectIterator obj_it(this);
for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next())
CollectHistogramInfo(obj);
ReportHistogram(heap()->isolate(), true);
}
#endif
// -----------------------------------------------------------------------------
// MapSpace implementation
#ifdef VERIFY_HEAP
void MapSpace::VerifyObject(HeapObject* object) { CHECK(object->IsMap()); }
#endif
Address LargePage::GetAddressToShrink() {
HeapObject* object = GetObject();
if (executable() == EXECUTABLE) {
return 0;
}
size_t used_size = RoundUp((object->address() - address()) + object->Size(),
MemoryAllocator::GetCommitPageSize());
if (used_size < CommittedPhysicalMemory()) {
return address() + used_size;
}
return 0;
}
void LargePage::ClearOutOfLiveRangeSlots(Address free_start) {
RememberedSet<OLD_TO_NEW>::RemoveRange(this, free_start, area_end(),
SlotSet::FREE_EMPTY_BUCKETS);
RememberedSet<OLD_TO_OLD>::RemoveRange(this, free_start, area_end(),
SlotSet::FREE_EMPTY_BUCKETS);
RememberedSet<OLD_TO_NEW>::RemoveRangeTyped(this, free_start, area_end());
RememberedSet<OLD_TO_OLD>::RemoveRangeTyped(this, free_start, area_end());
}
// -----------------------------------------------------------------------------
// LargeObjectIterator
LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) {
current_ = space->first_page_;
}
HeapObject* LargeObjectIterator::Next() {
if (current_ == NULL) return NULL;
HeapObject* object = current_->GetObject();
current_ = current_->next_page();
return object;
}
// -----------------------------------------------------------------------------
// LargeObjectSpace
LargeObjectSpace::LargeObjectSpace(Heap* heap, AllocationSpace id)
: Space(heap, id, NOT_EXECUTABLE), // Managed on a per-allocation basis
first_page_(NULL),
size_(0),
page_count_(0),
objects_size_(0),
chunk_map_(1024) {}
LargeObjectSpace::~LargeObjectSpace() {}
bool LargeObjectSpace::SetUp() {
first_page_ = NULL;
size_ = 0;
page_count_ = 0;
objects_size_ = 0;
chunk_map_.Clear();
return true;
}
void LargeObjectSpace::TearDown() {
while (first_page_ != NULL) {
LargePage* page = first_page_;
first_page_ = first_page_->next_page();
LOG(heap()->isolate(), DeleteEvent("LargeObjectChunk", page->address()));
heap()->memory_allocator()->Free<MemoryAllocator::kFull>(page);
}
SetUp();
}
AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
Executability executable) {
// Check if we want to force a GC before growing the old space further.
// If so, fail the allocation.
if (!heap()->CanExpandOldGeneration(object_size) ||
!heap()->ShouldExpandOldGenerationOnSlowAllocation()) {
return AllocationResult::Retry(identity());
}
LargePage* page = heap()->memory_allocator()->AllocateLargePage(
object_size, this, executable);
if (page == NULL) return AllocationResult::Retry(identity());
DCHECK_GE(page->area_size(), static_cast<size_t>(object_size));
size_ += static_cast<int>(page->size());
AccountCommitted(page->size());
objects_size_ += object_size;
page_count_++;
page->set_next_page(first_page_);
first_page_ = page;
InsertChunkMapEntries(page);
HeapObject* object = page->GetObject();
if (Heap::ShouldZapGarbage()) {
// Make the object consistent so the heap can be verified in OldSpaceStep.
// We only need to do this in debug builds or if verify_heap is on.
reinterpret_cast<Object**>(object->address())[0] =
heap()->fixed_array_map();
reinterpret_cast<Object**>(object->address())[1] = Smi::kZero;
}
heap()->StartIncrementalMarkingIfAllocationLimitIsReached(Heap::kNoGCFlags,
kNoGCCallbackFlags);
AllocationStep(object->address(), object_size);
heap()->CreateFillerObjectAt(object->address(), object_size,
ClearRecordedSlots::kNo);
if (heap()->incremental_marking()->black_allocation()) {
ObjectMarking::WhiteToBlack(object, MarkingState::Internal(object));
}
return object;
}
size_t LargeObjectSpace::CommittedPhysicalMemory() {
// On a platform that provides lazy committing of memory, we over-account
// the actually committed memory. There is no easy way right now to support
// precise accounting of committed memory in large object space.
return CommittedMemory();
}
// GC support
Object* LargeObjectSpace::FindObject(Address a) {
LargePage* page = FindPage(a);
if (page != NULL) {
return page->GetObject();
}
return Smi::kZero; // Signaling not found.
}
LargePage* LargeObjectSpace::FindPageThreadSafe(Address a) {
base::LockGuard<base::Mutex> guard(&chunk_map_mutex_);
return FindPage(a);
}
LargePage* LargeObjectSpace::FindPage(Address a) {
uintptr_t key = reinterpret_cast<uintptr_t>(a) / MemoryChunk::kAlignment;
base::HashMap::Entry* e = chunk_map_.Lookup(reinterpret_cast<void*>(key),
static_cast<uint32_t>(key));
if (e != NULL) {
DCHECK(e->value != NULL);
LargePage* page = reinterpret_cast<LargePage*>(e->value);
DCHECK(LargePage::IsValid(page));
if (page->Contains(a)) {
return page;
}
}
return NULL;
}
void LargeObjectSpace::ClearMarkingStateOfLiveObjects() {
LargeObjectIterator it(this);
for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
if (ObjectMarking::IsBlackOrGrey(obj, MarkingState::Internal(obj))) {
Marking::MarkWhite(
ObjectMarking::MarkBitFrom(obj, MarkingState::Internal(obj)));
MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
chunk->ResetProgressBar();
MarkingState::Internal(chunk).SetLiveBytes(0);
}
DCHECK(ObjectMarking::IsWhite(obj, MarkingState::Internal(obj)));
}
}
void LargeObjectSpace::InsertChunkMapEntries(LargePage* page) {
// Register all MemoryChunk::kAlignment-aligned chunks covered by
// this large page in the chunk map.
uintptr_t start = reinterpret_cast<uintptr_t>(page) / MemoryChunk::kAlignment;
uintptr_t limit = (reinterpret_cast<uintptr_t>(page) + (page->size() - 1)) /
MemoryChunk::kAlignment;
// There may be concurrent access on the chunk map. We have to take the lock
// here.
base::LockGuard<base::Mutex> guard(&chunk_map_mutex_);
for (uintptr_t key = start; key <= limit; key++) {
base::HashMap::Entry* entry = chunk_map_.InsertNew(
reinterpret_cast<void*>(key), static_cast<uint32_t>(key));
DCHECK(entry != NULL);
entry->value = page;
}
}
void LargeObjectSpace::RemoveChunkMapEntries(LargePage* page) {
RemoveChunkMapEntries(page, page->address());
}
void LargeObjectSpace::RemoveChunkMapEntries(LargePage* page,
Address free_start) {
uintptr_t start = RoundUp(reinterpret_cast<uintptr_t>(free_start),
MemoryChunk::kAlignment) /
MemoryChunk::kAlignment;
uintptr_t limit = (reinterpret_cast<uintptr_t>(page) + (page->size() - 1)) /
MemoryChunk::kAlignment;
for (uintptr_t key = start; key <= limit; key++) {
chunk_map_.Remove(reinterpret_cast<void*>(key), static_cast<uint32_t>(key));
}
}
void LargeObjectSpace::FreeUnmarkedObjects() {
LargePage* previous = NULL;
LargePage* current = first_page_;
while (current != NULL) {
HeapObject* object = current->GetObject();
DCHECK(!ObjectMarking::IsGrey(object, MarkingState::Internal(object)));
if (ObjectMarking::IsBlack(object, MarkingState::Internal(object))) {
Address free_start;
if ((free_start = current->GetAddressToShrink()) != 0) {
// TODO(hpayer): Perform partial free concurrently.
current->ClearOutOfLiveRangeSlots(free_start);
RemoveChunkMapEntries(current, free_start);
heap()->memory_allocator()->PartialFreeMemory(current, free_start);
}
previous = current;
current = current->next_page();
} else {
LargePage* page = current;
// Cut the chunk out from the chunk list.
current = current->next_page();
if (previous == NULL) {
first_page_ = current;
} else {
previous->set_next_page(current);
}
// Free the chunk.
size_ -= static_cast<int>(page->size());
AccountUncommitted(page->size());
objects_size_ -= object->Size();
page_count_--;
RemoveChunkMapEntries(page);
heap()->memory_allocator()->Free<MemoryAllocator::kPreFreeAndQueue>(page);
}
}
}
bool LargeObjectSpace::Contains(HeapObject* object) {
Address address = object->address();
MemoryChunk* chunk = MemoryChunk::FromAddress(address);
bool owned = (chunk->owner() == this);
SLOW_DCHECK(!owned || FindObject(address)->IsHeapObject());
return owned;
}
std::unique_ptr<ObjectIterator> LargeObjectSpace::GetObjectIterator() {
return std::unique_ptr<ObjectIterator>(new LargeObjectIterator(this));
}
#ifdef VERIFY_HEAP
// We do not assume that the large object iterator works, because it depends
// on the invariants we are checking during verification.
void LargeObjectSpace::Verify() {
for (LargePage* chunk = first_page_; chunk != NULL;
chunk = chunk->next_page()) {
// Each chunk contains an object that starts at the large object page's
// object area start.
HeapObject* object = chunk->GetObject();
Page* page = Page::FromAddress(object->address());
CHECK(object->address() == page->area_start());
// 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));
// We have only code, sequential strings, external strings
// (sequential strings that have been morphed into external
// strings), thin strings (sequential strings that have been
// morphed into thin strings), fixed arrays, fixed double arrays,
// byte arrays, and free space (right after allocation) in the
// large object space.
CHECK(object->IsAbstractCode() || object->IsSeqString() ||
object->IsExternalString() || object->IsThinString() ||
object->IsFixedArray() || object->IsFixedDoubleArray() ||
object->IsByteArray() || object->IsFreeSpace());
// The object itself should look OK.
object->ObjectVerify();
if (!FLAG_verify_heap_skip_remembered_set) {
heap()->VerifyRememberedSetFor(object);
}
// Byte arrays and strings don't have interior pointers.
if (object->IsAbstractCode()) {
VerifyPointersVisitor code_visitor;
object->IterateBody(map->instance_type(), object->Size(), &code_visitor);
} else if (object->IsFixedArray()) {
FixedArray* array = FixedArray::cast(object);
for (int j = 0; j < array->length(); j++) {
Object* element = array->get(j);
if (element->IsHeapObject()) {
HeapObject* element_object = HeapObject::cast(element);
CHECK(heap()->Contains(element_object));
CHECK(element_object->map()->IsMap());
}
}
}
}
}
#endif
#ifdef DEBUG
void LargeObjectSpace::Print() {
OFStream os(stdout);
LargeObjectIterator it(this);
for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
obj->Print(os);
}
}
void LargeObjectSpace::ReportStatistics() {
PrintF(" size: %" PRIuS "\n", size_);
int num_objects = 0;
ClearHistograms(heap()->isolate());
LargeObjectIterator it(this);
for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
num_objects++;
CollectHistogramInfo(obj);
}
PrintF(
" number of objects %d, "
"size of objects %" PRIuS "\n",
num_objects, objects_size_);
if (num_objects > 0) ReportHistogram(heap()->isolate(), false);
}
void Page::Print() {
// Make a best-effort to print the objects in the page.
PrintF("Page@%p in %s\n", static_cast<void*>(this->address()),
AllocationSpaceName(this->owner()->identity()));
printf(" --------------------------------------\n");
HeapObjectIterator objects(this);
unsigned mark_size = 0;
for (HeapObject* object = objects.Next(); object != NULL;
object = objects.Next()) {
bool is_marked =
ObjectMarking::IsBlackOrGrey(object, MarkingState::Internal(object));
PrintF(" %c ", (is_marked ? '!' : ' ')); // Indent a little.
if (is_marked) {
mark_size += object->Size();
}
object->ShortPrint();
PrintF("\n");
}
printf(" --------------------------------------\n");
printf(" Marked: %x, LiveCount: %" V8PRIdPTR "\n", mark_size,
MarkingState::Internal(this).live_bytes());
}
#endif // DEBUG
} // namespace internal
} // namespace v8