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/*
* Copyright (C) 2008 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.
*/
#include "space_bitmap-inl.h"
#include "base/stringprintf.h"
#include "mem_map.h"
#include "mirror/object-inl.h"
#include "mirror/class.h"
#include "mirror/art_field.h"
#include "mirror/object_array.h"
namespace art {
namespace gc {
namespace accounting {
template<size_t kAlignment>
size_t SpaceBitmap<kAlignment>::ComputeBitmapSize(uint64_t capacity) {
const uint64_t kBytesCoveredPerWord = kAlignment * kBitsPerWord;
return (RoundUp(capacity, kBytesCoveredPerWord) / kBytesCoveredPerWord) * kWordSize;
}
template<size_t kAlignment>
SpaceBitmap<kAlignment>* SpaceBitmap<kAlignment>::CreateFromMemMap(
const std::string& name, MemMap* mem_map, byte* heap_begin, size_t heap_capacity) {
CHECK(mem_map != nullptr);
uword* bitmap_begin = reinterpret_cast<uword*>(mem_map->Begin());
const size_t bitmap_size = ComputeBitmapSize(heap_capacity);
return new SpaceBitmap(name, mem_map, bitmap_begin, bitmap_size, heap_begin);
}
template<size_t kAlignment>
SpaceBitmap<kAlignment>::SpaceBitmap(const std::string& name, MemMap* mem_map, uword* bitmap_begin,
size_t bitmap_size, const void* heap_begin)
: mem_map_(mem_map), bitmap_begin_(bitmap_begin), bitmap_size_(bitmap_size),
heap_begin_(reinterpret_cast<uintptr_t>(heap_begin)),
name_(name) {
CHECK(bitmap_begin_ != nullptr);
CHECK_NE(bitmap_size, 0U);
}
template<size_t kAlignment>
SpaceBitmap<kAlignment>::~SpaceBitmap() {}
template<size_t kAlignment>
SpaceBitmap<kAlignment>* SpaceBitmap<kAlignment>::Create(
const std::string& name, byte* heap_begin, size_t heap_capacity) {
// Round up since heap_capacity is not necessarily a multiple of kAlignment * kBitsPerWord.
const size_t bitmap_size = ComputeBitmapSize(heap_capacity);
std::string error_msg;
std::unique_ptr<MemMap> mem_map(MemMap::MapAnonymous(name.c_str(), nullptr, bitmap_size,
PROT_READ | PROT_WRITE, false, &error_msg));
if (UNLIKELY(mem_map.get() == nullptr)) {
LOG(ERROR) << "Failed to allocate bitmap " << name << ": " << error_msg;
return nullptr;
}
return CreateFromMemMap(name, mem_map.release(), heap_begin, heap_capacity);
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::SetHeapLimit(uintptr_t new_end) {
DCHECK(IsAligned<kBitsPerWord * kAlignment>(new_end));
size_t new_size = OffsetToIndex(new_end - heap_begin_) * kWordSize;
if (new_size < bitmap_size_) {
bitmap_size_ = new_size;
}
// Not sure if doing this trim is necessary, since nothing past the end of the heap capacity
// should be marked.
}
template<size_t kAlignment>
std::string SpaceBitmap<kAlignment>::Dump() const {
return StringPrintf("%s: %p-%p", name_.c_str(), reinterpret_cast<void*>(HeapBegin()),
reinterpret_cast<void*>(HeapLimit()));
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::Clear() {
if (bitmap_begin_ != nullptr) {
mem_map_->MadviseDontNeedAndZero();
}
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::CopyFrom(SpaceBitmap* source_bitmap) {
DCHECK_EQ(Size(), source_bitmap->Size());
std::copy(source_bitmap->Begin(), source_bitmap->Begin() + source_bitmap->Size() / kWordSize, Begin());
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::Walk(ObjectCallback* callback, void* arg) {
CHECK(bitmap_begin_ != NULL);
CHECK(callback != NULL);
uintptr_t end = OffsetToIndex(HeapLimit() - heap_begin_ - 1);
uword* bitmap_begin = bitmap_begin_;
for (uintptr_t i = 0; i <= end; ++i) {
uword w = bitmap_begin[i];
if (w != 0) {
uintptr_t ptr_base = IndexToOffset(i) + heap_begin_;
do {
const size_t shift = CTZ(w);
mirror::Object* obj = reinterpret_cast<mirror::Object*>(ptr_base + shift * kAlignment);
(*callback)(obj, arg);
w ^= (static_cast<uword>(1)) << shift;
} while (w != 0);
}
}
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::SweepWalk(const SpaceBitmap<kAlignment>& live_bitmap,
const SpaceBitmap<kAlignment>& mark_bitmap,
uintptr_t sweep_begin, uintptr_t sweep_end,
SpaceBitmap::SweepCallback* callback, void* arg) {
CHECK(live_bitmap.bitmap_begin_ != nullptr);
CHECK(mark_bitmap.bitmap_begin_ != nullptr);
CHECK_EQ(live_bitmap.heap_begin_, mark_bitmap.heap_begin_);
CHECK_EQ(live_bitmap.bitmap_size_, mark_bitmap.bitmap_size_);
CHECK(callback != NULL);
CHECK_LE(sweep_begin, sweep_end);
CHECK_GE(sweep_begin, live_bitmap.heap_begin_);
if (sweep_end <= sweep_begin) {
return;
}
// TODO: rewrite the callbacks to accept a std::vector<mirror::Object*> rather than a mirror::Object**?
constexpr size_t buffer_size = kWordSize * kBitsPerWord;
#ifdef __LP64__
// Heap-allocate for smaller stack frame.
std::unique_ptr<mirror::Object*[]> pointer_buf_ptr(new mirror::Object*[buffer_size]);
mirror::Object** pointer_buf = pointer_buf_ptr.get();
#else
// Stack-allocate buffer as it's small enough.
mirror::Object* pointer_buf[buffer_size];
#endif
mirror::Object** pb = &pointer_buf[0];
size_t start = OffsetToIndex(sweep_begin - live_bitmap.heap_begin_);
size_t end = OffsetToIndex(sweep_end - live_bitmap.heap_begin_ - 1);
CHECK_LT(end, live_bitmap.Size() / kWordSize);
uword* live = live_bitmap.bitmap_begin_;
uword* mark = mark_bitmap.bitmap_begin_;
for (size_t i = start; i <= end; i++) {
uword garbage = live[i] & ~mark[i];
if (UNLIKELY(garbage != 0)) {
uintptr_t ptr_base = IndexToOffset(i) + live_bitmap.heap_begin_;
do {
const size_t shift = CTZ(garbage);
garbage ^= (static_cast<uword>(1)) << shift;
*pb++ = reinterpret_cast<mirror::Object*>(ptr_base + shift * kAlignment);
} while (garbage != 0);
// Make sure that there are always enough slots available for an
// entire word of one bits.
if (pb >= &pointer_buf[buffer_size - kBitsPerWord]) {
(*callback)(pb - &pointer_buf[0], &pointer_buf[0], arg);
pb = &pointer_buf[0];
}
}
}
if (pb > &pointer_buf[0]) {
(*callback)(pb - &pointer_buf[0], &pointer_buf[0], arg);
}
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::WalkInstanceFields(SpaceBitmap<kAlignment>* visited,
ObjectCallback* callback, mirror::Object* obj,
mirror::Class* klass, void* arg)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
// Visit fields of parent classes first.
mirror::Class* super = klass->GetSuperClass();
if (super != NULL) {
WalkInstanceFields(visited, callback, obj, super, arg);
}
// Walk instance fields
mirror::ObjectArray<mirror::ArtField>* fields = klass->GetIFields();
if (fields != NULL) {
for (int32_t i = 0; i < fields->GetLength(); i++) {
mirror::ArtField* field = fields->Get(i);
if (!field->IsPrimitiveType()) {
mirror::Object* value = field->GetObj(obj);
if (value != NULL) {
WalkFieldsInOrder(visited, callback, value, arg);
}
}
}
}
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::WalkFieldsInOrder(SpaceBitmap<kAlignment>* visited,
ObjectCallback* callback, mirror::Object* obj,
void* arg) {
if (visited->Test(obj)) {
return;
}
// visit the object itself
(*callback)(obj, arg);
visited->Set(obj);
// Walk instance fields of all objects
mirror::Class* klass = obj->GetClass();
WalkInstanceFields(visited, callback, obj, klass, arg);
// Walk static fields of a Class
if (obj->IsClass()) {
mirror::ObjectArray<mirror::ArtField>* fields = klass->GetSFields();
if (fields != NULL) {
for (int32_t i = 0; i < fields->GetLength(); i++) {
mirror::ArtField* field = fields->Get(i);
if (!field->IsPrimitiveType()) {
mirror::Object* value = field->GetObj(NULL);
if (value != NULL) {
WalkFieldsInOrder(visited, callback, value, arg);
}
}
}
}
} else if (obj->IsObjectArray()) {
// Walk elements of an object array
mirror::ObjectArray<mirror::Object>* obj_array = obj->AsObjectArray<mirror::Object>();
int32_t length = obj_array->GetLength();
for (int32_t i = 0; i < length; i++) {
mirror::Object* value = obj_array->Get(i);
if (value != NULL) {
WalkFieldsInOrder(visited, callback, value, arg);
}
}
}
}
template<size_t kAlignment>
void SpaceBitmap<kAlignment>::InOrderWalk(ObjectCallback* callback, void* arg) {
std::unique_ptr<SpaceBitmap<kAlignment>> visited(
Create("bitmap for in-order walk", reinterpret_cast<byte*>(heap_begin_),
IndexToOffset(bitmap_size_ / kWordSize)));
CHECK(bitmap_begin_ != nullptr);
CHECK(callback != nullptr);
uintptr_t end = Size() / kWordSize;
for (uintptr_t i = 0; i < end; ++i) {
// Need uint for unsigned shift.
uword w = bitmap_begin_[i];
if (UNLIKELY(w != 0)) {
uintptr_t ptr_base = IndexToOffset(i) + heap_begin_;
while (w != 0) {
const size_t shift = CTZ(w);
mirror::Object* obj = reinterpret_cast<mirror::Object*>(ptr_base + shift * kAlignment);
WalkFieldsInOrder(visited.get(), callback, obj, arg);
w ^= (static_cast<uword>(1)) << shift;
}
}
}
}
template class SpaceBitmap<kObjectAlignment>;
template class SpaceBitmap<kPageSize>;
} // namespace accounting
} // namespace gc
} // namespace art
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