/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_GC_SPACE_REGION_SPACE_H_
#define ART_RUNTIME_GC_SPACE_REGION_SPACE_H_
#include "gc/accounting/read_barrier_table.h"
#include "object_callbacks.h"
#include "space.h"
#include "thread.h"
namespace art {
namespace gc {
namespace space {
// A space that consists of equal-sized regions.
class RegionSpace FINAL : public ContinuousMemMapAllocSpace {
public:
typedef void(*WalkCallback)(void *start, void *end, size_t num_bytes, void* callback_arg);
SpaceType GetType() const OVERRIDE {
return kSpaceTypeRegionSpace;
}
// Create a region space mem map with the requested sizes. The requested base address is not
// guaranteed to be granted, if it is required, the caller should call Begin on the returned
// space to confirm the request was granted.
static MemMap* CreateMemMap(const std::string& name, size_t capacity, uint8_t* requested_begin);
static RegionSpace* Create(const std::string& name, MemMap* mem_map);
// Allocate num_bytes, returns null if the space is full.
mirror::Object* Alloc(Thread* self, size_t num_bytes, size_t* bytes_allocated,
size_t* usable_size, size_t* bytes_tl_bulk_allocated)
OVERRIDE REQUIRES(!region_lock_);
// Thread-unsafe allocation for when mutators are suspended, used by the semispace collector.
mirror::Object* AllocThreadUnsafe(Thread* self, size_t num_bytes, size_t* bytes_allocated,
size_t* usable_size, size_t* bytes_tl_bulk_allocated)
OVERRIDE REQUIRES(Locks::mutator_lock_) REQUIRES(!region_lock_);
// The main allocation routine.
template<bool kForEvac>
ALWAYS_INLINE mirror::Object* AllocNonvirtual(size_t num_bytes, size_t* bytes_allocated,
size_t* usable_size,
size_t* bytes_tl_bulk_allocated)
REQUIRES(!region_lock_);
// Allocate/free large objects (objects that are larger than the region size.)
template<bool kForEvac>
mirror::Object* AllocLarge(size_t num_bytes, size_t* bytes_allocated, size_t* usable_size,
size_t* bytes_tl_bulk_allocated) REQUIRES(!region_lock_);
void FreeLarge(mirror::Object* large_obj, size_t bytes_allocated) REQUIRES(!region_lock_);
// Return the storage space required by obj.
size_t AllocationSize(mirror::Object* obj, size_t* usable_size) OVERRIDE
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!region_lock_) {
return AllocationSizeNonvirtual(obj, usable_size);
}
size_t AllocationSizeNonvirtual(mirror::Object* obj, size_t* usable_size)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!region_lock_);
size_t Free(Thread*, mirror::Object*) OVERRIDE {
UNIMPLEMENTED(FATAL);
return 0;
}
size_t FreeList(Thread*, size_t, mirror::Object**) OVERRIDE {
UNIMPLEMENTED(FATAL);
return 0;
}
accounting::ContinuousSpaceBitmap* GetLiveBitmap() const OVERRIDE {
return mark_bitmap_.get();
}
accounting::ContinuousSpaceBitmap* GetMarkBitmap() const OVERRIDE {
return mark_bitmap_.get();
}
void Clear() OVERRIDE REQUIRES(!region_lock_);
void Dump(std::ostream& os) const;
void DumpRegions(std::ostream& os) REQUIRES(!region_lock_);
void DumpNonFreeRegions(std::ostream& os) REQUIRES(!region_lock_);
size_t RevokeThreadLocalBuffers(Thread* thread) REQUIRES(!region_lock_);
void RevokeThreadLocalBuffersLocked(Thread* thread) REQUIRES(region_lock_);
size_t RevokeAllThreadLocalBuffers()
REQUIRES(!Locks::runtime_shutdown_lock_, !Locks::thread_list_lock_, !region_lock_);
void AssertThreadLocalBuffersAreRevoked(Thread* thread) REQUIRES(!region_lock_);
void AssertAllThreadLocalBuffersAreRevoked()
REQUIRES(!Locks::runtime_shutdown_lock_, !Locks::thread_list_lock_, !region_lock_);
enum class RegionType : uint8_t {
kRegionTypeAll, // All types.
kRegionTypeFromSpace, // From-space. To be evacuated.
kRegionTypeUnevacFromSpace, // Unevacuated from-space. Not to be evacuated.
kRegionTypeToSpace, // To-space.
kRegionTypeNone, // None.
};
enum class RegionState : uint8_t {
kRegionStateFree, // Free region.
kRegionStateAllocated, // Allocated region.
kRegionStateLarge, // Large allocated (allocation larger than the region size).
kRegionStateLargeTail, // Large tail (non-first regions of a large allocation).
};
template<RegionType kRegionType> uint64_t GetBytesAllocatedInternal() REQUIRES(!region_lock_);
template<RegionType kRegionType> uint64_t GetObjectsAllocatedInternal() REQUIRES(!region_lock_);
uint64_t GetBytesAllocated() REQUIRES(!region_lock_) {
return GetBytesAllocatedInternal<RegionType::kRegionTypeAll>();
}
uint64_t GetObjectsAllocated() REQUIRES(!region_lock_) {
return GetObjectsAllocatedInternal<RegionType::kRegionTypeAll>();
}
uint64_t GetBytesAllocatedInFromSpace() REQUIRES(!region_lock_) {
return GetBytesAllocatedInternal<RegionType::kRegionTypeFromSpace>();
}
uint64_t GetObjectsAllocatedInFromSpace() REQUIRES(!region_lock_) {
return GetObjectsAllocatedInternal<RegionType::kRegionTypeFromSpace>();
}
uint64_t GetBytesAllocatedInUnevacFromSpace() REQUIRES(!region_lock_) {
return GetBytesAllocatedInternal<RegionType::kRegionTypeUnevacFromSpace>();
}
uint64_t GetObjectsAllocatedInUnevacFromSpace() REQUIRES(!region_lock_) {
return GetObjectsAllocatedInternal<RegionType::kRegionTypeUnevacFromSpace>();
}
bool CanMoveObjects() const OVERRIDE {
return true;
}
bool Contains(const mirror::Object* obj) const {
const uint8_t* byte_obj = reinterpret_cast<const uint8_t*>(obj);
return byte_obj >= Begin() && byte_obj < Limit();
}
RegionSpace* AsRegionSpace() OVERRIDE {
return this;
}
// Go through all of the blocks and visit the continuous objects.
void Walk(ObjectCallback* callback, void* arg)
REQUIRES(Locks::mutator_lock_) {
WalkInternal<false>(callback, arg);
}
void WalkToSpace(ObjectCallback* callback, void* arg)
REQUIRES(Locks::mutator_lock_) {
WalkInternal<true>(callback, arg);
}
accounting::ContinuousSpaceBitmap::SweepCallback* GetSweepCallback() OVERRIDE {
return nullptr;
}
void LogFragmentationAllocFailure(std::ostream& os, size_t failed_alloc_bytes) OVERRIDE
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!region_lock_);
// Object alignment within the space.
static constexpr size_t kAlignment = kObjectAlignment;
// The region size.
static constexpr size_t kRegionSize = 256 * KB;
bool IsInFromSpace(mirror::Object* ref) {
if (HasAddress(ref)) {
Region* r = RefToRegionUnlocked(ref);
return r->IsInFromSpace();
}
return false;
}
bool IsInNewlyAllocatedRegion(mirror::Object* ref) {
if (HasAddress(ref)) {
Region* r = RefToRegionUnlocked(ref);
return r->IsNewlyAllocated();
}
return false;
}
bool IsInUnevacFromSpace(mirror::Object* ref) {
if (HasAddress(ref)) {
Region* r = RefToRegionUnlocked(ref);
return r->IsInUnevacFromSpace();
}
return false;
}
bool IsInToSpace(mirror::Object* ref) {
if (HasAddress(ref)) {
Region* r = RefToRegionUnlocked(ref);
return r->IsInToSpace();
}
return false;
}
RegionType GetRegionType(mirror::Object* ref) {
if (HasAddress(ref)) {
Region* r = RefToRegionUnlocked(ref);
return r->Type();
}
return RegionType::kRegionTypeNone;
}
void SetFromSpace(accounting::ReadBarrierTable* rb_table, bool force_evacuate_all)
REQUIRES(!region_lock_);
size_t FromSpaceSize() REQUIRES(!region_lock_);
size_t UnevacFromSpaceSize() REQUIRES(!region_lock_);
size_t ToSpaceSize() REQUIRES(!region_lock_);
void ClearFromSpace(uint64_t* cleared_bytes, uint64_t* cleared_objects) REQUIRES(!region_lock_);
void AddLiveBytes(mirror::Object* ref, size_t alloc_size) {
Region* reg = RefToRegionUnlocked(ref);
reg->AddLiveBytes(alloc_size);
}
void AssertAllRegionLiveBytesZeroOrCleared() REQUIRES(!region_lock_) {
if (kIsDebugBuild) {
MutexLock mu(Thread::Current(), region_lock_);
for (size_t i = 0; i < num_regions_; ++i) {
Region* r = ®ions_[i];
size_t live_bytes = r->LiveBytes();
CHECK(live_bytes == 0U || live_bytes == static_cast<size_t>(-1)) << live_bytes;
}
}
}
void RecordAlloc(mirror::Object* ref) REQUIRES(!region_lock_);
bool AllocNewTlab(Thread* self, size_t min_bytes) REQUIRES(!region_lock_);
uint32_t Time() {
return time_;
}
private:
RegionSpace(const std::string& name, MemMap* mem_map);
template<bool kToSpaceOnly>
void WalkInternal(ObjectCallback* callback, void* arg) NO_THREAD_SAFETY_ANALYSIS;
class Region {
public:
Region()
: idx_(static_cast<size_t>(-1)),
begin_(nullptr), top_(nullptr), end_(nullptr),
state_(RegionState::kRegionStateAllocated), type_(RegionType::kRegionTypeToSpace),
objects_allocated_(0), alloc_time_(0), live_bytes_(static_cast<size_t>(-1)),
is_newly_allocated_(false), is_a_tlab_(false), thread_(nullptr) {}
void Init(size_t idx, uint8_t* begin, uint8_t* end) {
idx_ = idx;
begin_ = begin;
top_.StoreRelaxed(begin);
end_ = end;
state_ = RegionState::kRegionStateFree;
type_ = RegionType::kRegionTypeNone;
objects_allocated_.StoreRelaxed(0);
alloc_time_ = 0;
live_bytes_ = static_cast<size_t>(-1);
is_newly_allocated_ = false;
is_a_tlab_ = false;
thread_ = nullptr;
DCHECK_LT(begin, end);
DCHECK_EQ(static_cast<size_t>(end - begin), kRegionSize);
}
RegionState State() const {
return state_;
}
RegionType Type() const {
return type_;
}
void Clear(bool zero_and_release_pages) {
top_.StoreRelaxed(begin_);
state_ = RegionState::kRegionStateFree;
type_ = RegionType::kRegionTypeNone;
objects_allocated_.StoreRelaxed(0);
alloc_time_ = 0;
live_bytes_ = static_cast<size_t>(-1);
if (zero_and_release_pages) {
ZeroAndReleasePages(begin_, end_ - begin_);
}
is_newly_allocated_ = false;
is_a_tlab_ = false;
thread_ = nullptr;
}
ALWAYS_INLINE mirror::Object* Alloc(size_t num_bytes, size_t* bytes_allocated,
size_t* usable_size,
size_t* bytes_tl_bulk_allocated);
bool IsFree() const {
bool is_free = state_ == RegionState::kRegionStateFree;
if (is_free) {
DCHECK(IsInNoSpace());
DCHECK_EQ(begin_, Top());
DCHECK_EQ(objects_allocated_.LoadRelaxed(), 0U);
}
return is_free;
}
// Given a free region, declare it non-free (allocated).
void Unfree(RegionSpace* region_space, uint32_t alloc_time)
REQUIRES(region_space->region_lock_) {
DCHECK(IsFree());
state_ = RegionState::kRegionStateAllocated;
type_ = RegionType::kRegionTypeToSpace;
alloc_time_ = alloc_time;
region_space->AdjustNonFreeRegionLimit(idx_);
}
void UnfreeLarge(RegionSpace* region_space, uint32_t alloc_time)
REQUIRES(region_space->region_lock_) {
DCHECK(IsFree());
state_ = RegionState::kRegionStateLarge;
type_ = RegionType::kRegionTypeToSpace;
alloc_time_ = alloc_time;
region_space->AdjustNonFreeRegionLimit(idx_);
}
void UnfreeLargeTail(RegionSpace* region_space, uint32_t alloc_time)
REQUIRES(region_space->region_lock_) {
DCHECK(IsFree());
state_ = RegionState::kRegionStateLargeTail;
type_ = RegionType::kRegionTypeToSpace;
alloc_time_ = alloc_time;
region_space->AdjustNonFreeRegionLimit(idx_);
}
void SetNewlyAllocated() {
is_newly_allocated_ = true;
}
// Non-large, non-large-tail allocated.
bool IsAllocated() const {
return state_ == RegionState::kRegionStateAllocated;
}
// Large allocated.
bool IsLarge() const {
bool is_large = state_ == RegionState::kRegionStateLarge;
if (is_large) {
DCHECK_LT(begin_ + kRegionSize, Top());
}
return is_large;
}
// Large-tail allocated.
bool IsLargeTail() const {
bool is_large_tail = state_ == RegionState::kRegionStateLargeTail;
if (is_large_tail) {
DCHECK_EQ(begin_, Top());
}
return is_large_tail;
}
size_t Idx() const {
return idx_;
}
bool IsNewlyAllocated() const {
return is_newly_allocated_;
}
bool IsInFromSpace() const {
return type_ == RegionType::kRegionTypeFromSpace;
}
bool IsInToSpace() const {
return type_ == RegionType::kRegionTypeToSpace;
}
bool IsInUnevacFromSpace() const {
return type_ == RegionType::kRegionTypeUnevacFromSpace;
}
bool IsInNoSpace() const {
return type_ == RegionType::kRegionTypeNone;
}
void SetAsFromSpace() {
DCHECK(!IsFree() && IsInToSpace());
type_ = RegionType::kRegionTypeFromSpace;
live_bytes_ = static_cast<size_t>(-1);
}
void SetAsUnevacFromSpace() {
DCHECK(!IsFree() && IsInToSpace());
type_ = RegionType::kRegionTypeUnevacFromSpace;
live_bytes_ = 0U;
}
void SetUnevacFromSpaceAsToSpace() {
DCHECK(!IsFree() && IsInUnevacFromSpace());
type_ = RegionType::kRegionTypeToSpace;
}
ALWAYS_INLINE bool ShouldBeEvacuated();
void AddLiveBytes(size_t live_bytes) {
DCHECK(IsInUnevacFromSpace());
DCHECK(!IsLargeTail());
DCHECK_NE(live_bytes_, static_cast<size_t>(-1));
live_bytes_ += live_bytes;
DCHECK_LE(live_bytes_, BytesAllocated());
}
size_t LiveBytes() const {
return live_bytes_;
}
size_t BytesAllocated() const;
size_t ObjectsAllocated() const {
if (IsLarge()) {
DCHECK_LT(begin_ + kRegionSize, Top());
DCHECK_EQ(objects_allocated_.LoadRelaxed(), 0U);
return 1;
} else if (IsLargeTail()) {
DCHECK_EQ(begin_, Top());
DCHECK_EQ(objects_allocated_.LoadRelaxed(), 0U);
return 0;
} else {
DCHECK(IsAllocated()) << static_cast<uint>(state_);
return objects_allocated_;
}
}
uint8_t* Begin() const {
return begin_;
}
ALWAYS_INLINE uint8_t* Top() const {
return top_.LoadRelaxed();
}
void SetTop(uint8_t* new_top) {
top_.StoreRelaxed(new_top);
}
uint8_t* End() const {
return end_;
}
bool Contains(mirror::Object* ref) const {
return begin_ <= reinterpret_cast<uint8_t*>(ref) && reinterpret_cast<uint8_t*>(ref) < end_;
}
void Dump(std::ostream& os) const;
void RecordThreadLocalAllocations(size_t num_objects, size_t num_bytes) {
DCHECK(IsAllocated());
DCHECK_EQ(objects_allocated_.LoadRelaxed(), 0U);
DCHECK_EQ(Top(), end_);
objects_allocated_.StoreRelaxed(num_objects);
top_.StoreRelaxed(begin_ + num_bytes);
DCHECK_LE(Top(), end_);
}
private:
size_t idx_; // The region's index in the region space.
uint8_t* begin_; // The begin address of the region.
Atomic<uint8_t*> top_; // The current position of the allocation.
uint8_t* end_; // The end address of the region.
RegionState state_; // The region state (see RegionState).
RegionType type_; // The region type (see RegionType).
Atomic<size_t> objects_allocated_; // The number of objects allocated.
uint32_t alloc_time_; // The allocation time of the region.
size_t live_bytes_; // The live bytes. Used to compute the live percent.
bool is_newly_allocated_; // True if it's allocated after the last collection.
bool is_a_tlab_; // True if it's a tlab.
Thread* thread_; // The owning thread if it's a tlab.
friend class RegionSpace;
};
Region* RefToRegion(mirror::Object* ref) REQUIRES(!region_lock_) {
MutexLock mu(Thread::Current(), region_lock_);
return RefToRegionLocked(ref);
}
Region* RefToRegionUnlocked(mirror::Object* ref) NO_THREAD_SAFETY_ANALYSIS {
// For a performance reason (this is frequently called via
// IsInFromSpace() etc.) we avoid taking a lock here. Note that
// since we only change a region from to-space to from-space only
// during a pause (SetFromSpace()) and from from-space to free
// (after GC is done) as long as ref is a valid reference into an
// allocated region, it's safe to access the region state without
// the lock.
return RefToRegionLocked(ref);
}
Region* RefToRegionLocked(mirror::Object* ref) REQUIRES(region_lock_) {
DCHECK(HasAddress(ref));
uintptr_t offset = reinterpret_cast<uintptr_t>(ref) - reinterpret_cast<uintptr_t>(Begin());
size_t reg_idx = offset / kRegionSize;
DCHECK_LT(reg_idx, num_regions_);
Region* reg = ®ions_[reg_idx];
DCHECK_EQ(reg->Idx(), reg_idx);
DCHECK(reg->Contains(ref));
return reg;
}
mirror::Object* GetNextObject(mirror::Object* obj)
REQUIRES_SHARED(Locks::mutator_lock_);
void AdjustNonFreeRegionLimit(size_t new_non_free_region_index) REQUIRES(region_lock_) {
DCHECK_LT(new_non_free_region_index, num_regions_);
non_free_region_index_limit_ = std::max(non_free_region_index_limit_,
new_non_free_region_index + 1);
VerifyNonFreeRegionLimit();
}
void SetNonFreeRegionLimit(size_t new_non_free_region_index_limit) REQUIRES(region_lock_) {
DCHECK_LE(new_non_free_region_index_limit, num_regions_);
non_free_region_index_limit_ = new_non_free_region_index_limit;
VerifyNonFreeRegionLimit();
}
void VerifyNonFreeRegionLimit() REQUIRES(region_lock_) {
if (kIsDebugBuild && non_free_region_index_limit_ < num_regions_) {
for (size_t i = non_free_region_index_limit_; i < num_regions_; ++i) {
CHECK(regions_[i].IsFree());
}
}
}
Mutex region_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
uint32_t time_; // The time as the number of collections since the startup.
size_t num_regions_; // The number of regions in this space.
size_t num_non_free_regions_; // The number of non-free regions in this space.
std::unique_ptr<Region[]> regions_ GUARDED_BY(region_lock_);
// The pointer to the region array.
// The upper-bound index of the non-free regions. Used to avoid scanning all regions in
// SetFromSpace(). Invariant: for all i >= non_free_region_index_limit_, regions_[i].IsFree() is
// true.
size_t non_free_region_index_limit_ GUARDED_BY(region_lock_);
Region* current_region_; // The region that's being allocated currently.
Region* evac_region_; // The region that's being evacuated to currently.
Region full_region_; // The dummy/sentinel region that looks full.
// Mark bitmap used by the GC.
std::unique_ptr<accounting::ContinuousSpaceBitmap> mark_bitmap_;
DISALLOW_COPY_AND_ASSIGN(RegionSpace);
};
std::ostream& operator<<(std::ostream& os, const RegionSpace::RegionState& value);
std::ostream& operator<<(std::ostream& os, const RegionSpace::RegionType& value);
} // namespace space
} // namespace gc
} // namespace art
#endif // ART_RUNTIME_GC_SPACE_REGION_SPACE_H_