未验证 提交 6e3cc0c9 编写于 作者: Y Yu Yang 提交者: GitHub

Merge pull request #7240 from reyoung/feature/make_lod_a_share_ptr

Add COWPtr and its unittest
......@@ -79,6 +79,6 @@ cc_library(init SRCS init.cc DEPS gflags device_context place stringpiece operat
cc_test(init_test SRCS init_test.cc DEPS init)
cc_test(op_kernel_type_test SRCS op_kernel_type_test.cc DEPS place device_context framework_proto)
cc_test(cow_ptr_tests SRCS details/cow_ptr_test.cc)
nv_test(device_data_transform_test SRCS device_data_transform_test.cu
DEPS operator op_registry init math_function)
/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
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. */
#pragma once
#include <memory>
#include <thread>
namespace paddle {
namespace framework {
namespace details {
// Change it to thread safe flags if needed.
class ThreadUnsafeOwnershipFlags {
public:
ThreadUnsafeOwnershipFlags(bool flag) : flag_(flag) {}
ThreadUnsafeOwnershipFlags(const ThreadUnsafeOwnershipFlags& other) = delete;
ThreadUnsafeOwnershipFlags& operator=(
const ThreadUnsafeOwnershipFlags& other) = delete;
ThreadUnsafeOwnershipFlags(ThreadUnsafeOwnershipFlags&& other) = default;
void SetOwnership(bool flag) { flag_ = flag; }
// Invoke the callback if it is not owned.
template <typename Callback>
void AcquireOwnershipOnce(Callback acquire) {
if (!flag_) {
acquire();
flag_ = true;
}
}
private:
bool flag_;
};
// Copy-On-Write pointer.
// It will hold a T* pointer, and only copy once when `MutableData` is invoked.
//
// The template parameter OwnershipFlags should have:
// * a constructor takes a bool. True if own.
// * SetOwnership(bool flag).
// * AcquireOwnershipOnce(Callback). It will invoke the callback if it is not
// owned.
//
// https://en.wikipedia.org/wiki/Copy-on-write
template <typename T, typename OwnershipFlags = ThreadUnsafeOwnershipFlags>
class COWPtr {
public:
// Ctor from raw pointer.
explicit COWPtr(T* ptr) : payload_(ptr), ownership_{true} {}
// Move methods. Steal ownership from origin
COWPtr(COWPtr&& other)
: payload_(other.payload_), ownership_{std::move(other.ownership_)} {}
COWPtr& operator=(COWPtr&& origin) = default;
// Copy methods. Not own payload
COWPtr(const COWPtr& other) : payload_(other.payload_), ownership_{false} {}
COWPtr& operator=(const COWPtr& other) {
payload_ = other.payload_;
ownership_.SetOwnership(false);
return *this;
}
// Access read only data.
const T& Data() const { return *payload_; }
// Access mutable data. If the data is not owned, the data will be copied
// before.
T* MutableData() {
ownership_.AcquireOwnershipOnce(
[this] { payload_.reset(new T(*payload_)); });
return payload_.get();
}
private:
// Actual data pointer.
std::shared_ptr<T> payload_;
// Ownership flag.
OwnershipFlags ownership_;
};
} // namespace details
} // namespace framework
} // namespace paddle
/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
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 "paddle/framework/details/cow_ptr.h"
#include "gtest/gtest.h"
namespace paddle {
namespace framework {
namespace details {
TEST(COWPtr, all) {
COWPtr<int> ptr(new int{0});
ASSERT_EQ(ptr.Data(), 0);
COWPtr<int> ptr2 = ptr;
ASSERT_EQ(ptr2.Data(), 0);
ASSERT_EQ(&ptr2.Data(), &ptr.Data());
*ptr2.MutableData() = 10;
ASSERT_EQ(ptr.Data(), 0);
ASSERT_EQ(ptr2.Data(), 10);
}
} // namespace details
} // namespace framework
} // namespace paddle
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