Fix mem leak when converting Tensor to numpy array (#17182)

* fix mem leak when converting Tensor to numpy array
test=develop

* remove unused unittest,test=develop

* follow comments, test=develop

* fix dygraph bug,test=develop

paddle/fluid/pybind/CMakeLists.txt

@@ -26,5 +26,4 @@ if(WITH_PYTHON)
   get_property (os_dependency_modules GLOBAL PROPERTY OS_DEPENDENCY_MODULES)
   target_link_libraries(paddle_pybind ${os_dependency_modules})
 
-  cc_test(tensor_py_test SRCS tensor_py_test.cc DEPS python pybind)
 endif(WITH_PYTHON)

paddle/fluid/pybind/pybind.cc

@@ -302,8 +302,7 @@ PYBIND11_MODULE(core, m) {
   BindImperative(&m);
 
   py::class_<Tensor>(m, "Tensor", py::buffer_protocol())
-      .def_buffer(
-          [](Tensor &self) -> py::buffer_info { return CastToPyBuffer(self); })
+      .def("__array__", [](Tensor &self) { return TensorToPyArray(self); })
       .def("_is_initialized",
            [](const Tensor &self) { return self.IsInitialized(); })
       .def("_get_dims",
@@ -419,8 +418,7 @@ PYBIND11_MODULE(core, m) {
       Users should be careful about it.
 
         )DOC")
-      .def_buffer(
-          [](Tensor &self) -> py::buffer_info { return CastToPyBuffer(self); })
+      .def("__array__", [](Tensor &self) { return TensorToPyArray(self); })
       .def("__init__",
            [](LoDTensor &instance, const std::vector<std::vector<size_t>>
                                        &recursive_sequence_lengths) {

paddle/fluid/pybind/tensor_py.h

@@ -32,109 +32,6 @@ namespace py = pybind11;
 
 namespace paddle {
 namespace pybind {
-namespace details {
-
-template <bool less, size_t I, typename... ARGS>
-struct CastToPyBufferImpl;
-
-template <size_t I, typename... ARGS>
-struct CastToPyBufferImpl<false, I, ARGS...> {
-  pybind11::buffer_info operator()(const framework::Tensor &tensor) {
-    PADDLE_THROW("This type of tensor cannot be expose to Python");
-    return pybind11::buffer_info();
-  }
-};
-
-template <size_t I, typename... ARGS>
-struct CastToPyBufferImpl<true, I, ARGS...> {
-  using CUR_TYPE = typename std::tuple_element<I, std::tuple<ARGS...>>::type;
-  pybind11::buffer_info operator()(const framework::Tensor &tensor) {
-    if (framework::DataTypeTrait<CUR_TYPE>::DataType == tensor.type()) {
-      auto dim_vec = framework::vectorize(tensor.dims());
-      std::vector<size_t> dims_outside;
-      std::vector<size_t> strides;
-      dims_outside.resize(dim_vec.size());
-      strides.resize(dim_vec.size());
-
-      size_t prod = 1;
-      for (size_t i = dim_vec.size(); i != 0; --i) {
-        dims_outside[i - 1] = (size_t)dim_vec[i - 1];
-        strides[i - 1] = sizeof(CUR_TYPE) * prod;
-        prod *= dims_outside[i - 1];
-      }
-      framework::Tensor dst_tensor;
-      bool is_gpu = paddle::platform::is_gpu_place(tensor.place());
-      if (is_gpu) {
-#ifdef PADDLE_WITH_CUDA
-        auto *src_ptr = static_cast<const void *>(tensor.data<CUR_TYPE>());
-        auto *dst_ptr = static_cast<void *>(dst_tensor.mutable_data<CUR_TYPE>(
-            tensor.dims(), platform::CPUPlace()));
-
-        paddle::platform::GpuMemcpySync(dst_ptr, src_ptr,
-                                        sizeof(CUR_TYPE) * tensor.numel(),
-                                        cudaMemcpyDeviceToHost);
-#else
-        PADDLE_THROW("'CUDAPlace' is not supported in CPU only device.");
-#endif
-      } else if (paddle::platform::is_cpu_place(tensor.place())) {
-        dst_tensor = tensor;
-      }
-
-      std::string dtype = std::type_index(typeid(CUR_TYPE)) ==
-                                  std::type_index(typeid(platform::float16))
-                              ? std::string("e")  // np.dtype('e') == np.float16
-                              : pybind11::format_descriptor<CUR_TYPE>::format();
-
-      if (is_gpu) {
-        // manually construct a py_buffer if is_gpu since gpu data is copied
-        // into CPU.
-        // TODO(yy): Is these following code memleak?
-        Py_buffer *py_buffer =
-            reinterpret_cast<Py_buffer *>(malloc(sizeof(Py_buffer)));
-        py_buffer->format = strdup(dtype.c_str());
-        py_buffer->itemsize = sizeof(CUR_TYPE);
-        py_buffer->ndim = framework::arity(dst_tensor.dims());
-        py_buffer->len = tensor.numel();
-        py_buffer->strides = reinterpret_cast<Py_ssize_t *>(
-            malloc(sizeof(Py_ssize_t) * strides.size()));
-        for (size_t i = 0; i < strides.size(); ++i) {
-          py_buffer->strides[i] = strides[i];
-        }
-
-        py_buffer->shape = reinterpret_cast<Py_ssize_t *>(
-            malloc(sizeof(Py_ssize_t) * tensor.dims().size()));
-        for (int i = 0; i < tensor.dims().size(); ++i) {
-          py_buffer->shape[i] = tensor.dims()[i];
-        }
-
-        py_buffer->readonly = false;
-        py_buffer->suboffsets = nullptr;
-        py_buffer->obj = nullptr;
-        py_buffer->buf =
-            malloc(static_cast<size_t>(py_buffer->len * py_buffer->itemsize));
-        memcpy(py_buffer->buf, dst_tensor.data<CUR_TYPE>(),
-               static_cast<size_t>(py_buffer->len * py_buffer->itemsize));
-        return pybind11::buffer_info(py_buffer, true);
-      } else {
-        return pybind11::buffer_info(
-            dst_tensor.data<CUR_TYPE>(), sizeof(CUR_TYPE), dtype,
-            (size_t)framework::arity(dst_tensor.dims()), dims_outside, strides);
-      }
-    } else {
-      constexpr bool less = I + 1 < std::tuple_size<std::tuple<ARGS...>>::value;
-      return CastToPyBufferImpl<less, I + 1, ARGS...>()(tensor);
-    }
-  }
-};
-
-}  // namespace details
-
-inline pybind11::buffer_info CastToPyBuffer(const framework::Tensor &tensor) {
-  auto buffer_info =
-      details::CastToPyBufferImpl<true, 0, float, int, double, int64_t, bool,
-                                  uint8_t, int8_t, platform::float16>()(tensor);
-  return buffer_info;
-}
 
 template <typename T>
 T TensorGetElement(const framework::Tensor &self, size_t offset) {
@@ -531,5 +428,88 @@ inline void PyCUDAPinnedTensorSetFromArray(
 }
 #endif
 
+namespace details {
+
+template <typename T>
+constexpr bool IsValidDTypeToPyArray() {
+  return false;
+}
+
+#define DECLARE_VALID_DTYPE_TO_PY_ARRAY(type)    \
+  template <>                                    \
+  constexpr bool IsValidDTypeToPyArray<type>() { \
+    return true;                                 \
+  }
+
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(platform::float16);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(float);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(double);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(bool);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(int8_t);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(uint8_t);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(int);
+DECLARE_VALID_DTYPE_TO_PY_ARRAY(int64_t);
+
+inline std::string TensorDTypeToPyDTypeStr(
+    framework::proto::VarType::Type type) {
+#define TENSOR_DTYPE_TO_PY_DTYPE(T, proto_type)                         \
+  if (type == proto_type) {                                             \
+    if (std::is_same<T, platform::float16>::value) {                    \
+      return "e";                                                       \
+    } else {                                                            \
+      PADDLE_ENFORCE(IsValidDTypeToPyArray<T>,                          \
+                     "This type of tensor cannot be expose to Python"); \
+      return py::format_descriptor<T>::format();                        \
+    }                                                                   \
+  }
+
+  _ForEachDataType_(TENSOR_DTYPE_TO_PY_DTYPE);
+#undef TENSOR_DTYPE_TO_PY_DTYPE
+  PADDLE_THROW("Unsupported data type %d", static_cast<int>(type));
+}
+
+}  // namespace details
+
+inline py::array TensorToPyArray(const framework::Tensor &tensor) {
+  bool is_gpu_tensor = platform::is_gpu_place(tensor.place());
+  const auto &tensor_dims = tensor.dims();
+  auto tensor_dtype = tensor.type();
+  size_t sizeof_dtype = framework::SizeOfType(tensor_dtype);
+
+  std::vector<size_t> py_dims(tensor_dims.size());
+  std::vector<size_t> py_strides(tensor_dims.size());
+
+  size_t numel = 1;
+  for (int i = tensor_dims.size() - 1; i >= 0; --i) {
+    py_dims[i] = (size_t)tensor_dims[i];
+    py_strides[i] = sizeof_dtype * numel;
+    numel *= py_dims[i];
+  }
+
+  const void *tensor_buf_ptr = tensor.data<void>();
+
+  std::string py_dtype_str = details::TensorDTypeToPyDTypeStr(tensor.type());
+
+  if (!is_gpu_tensor) {
+    return py::array(py::buffer_info(
+        const_cast<void *>(tensor_buf_ptr), sizeof_dtype, py_dtype_str,
+        static_cast<size_t>(tensor.dims().size()), py_dims, py_strides));
+  }
+
+#ifdef PADDLE_WITH_CUDA
+  py::array py_arr(py::dtype(py_dtype_str.c_str()), py_dims, py_strides);
+  PADDLE_ENFORCE(py_arr.writeable() && py_arr.owndata(),
+                 "PyArray must be writable and own data, otherwise memory leak "
+                 "or double free would occur");
+
+  size_t copy_bytes = sizeof_dtype * numel;
+  paddle::platform::GpuMemcpySync(py_arr.mutable_data(), tensor_buf_ptr,
+                                  copy_bytes, cudaMemcpyDeviceToHost);
+  return py_arr;
+#else
+  PADDLE_THROW("CUDAPlace is not supported when not compiled with CUDA");
+#endif
+}
+
 }  // namespace pybind
 }  // namespace paddle

paddle/fluid/pybind/tensor_py_test.cc

-//   Copyright (c) 2018 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/fluid/pybind/tensor_py.h"
-
-#include <iostream>
-
-#include "gtest/gtest.h"
-#include "paddle/fluid/framework/tensor.h"
-
-TEST(TensorPy, CastToPyBufferImpl) {
-  typedef int ElemType;
-
-  paddle::framework::Tensor t;
-  auto d = paddle::framework::make_ddim({1, 2, 3});
-  int* p = t.mutable_data<ElemType>(d, paddle::platform::CPUPlace());
-  for (int i = 0; i < paddle::framework::product(d); ++i) {
-    p[i] = i;
-  }
-
-  pybind11::buffer_info bi = paddle::pybind::CastToPyBuffer(t);
-  EXPECT_EQ(bi.itemsize, static_cast<size_t>(sizeof(ElemType)));
-  EXPECT_EQ(bi.size, static_cast<size_t>(paddle::framework::product(d)));
-  EXPECT_EQ(bi.ndim, static_cast<size_t>(3));  // 3-dimensional as d.
-  EXPECT_EQ(bi.shape.size(), 3U);              // as Dim d.
-  EXPECT_EQ(bi.shape[0], static_cast<size_t>(1));
-  EXPECT_EQ(bi.shape[1], static_cast<size_t>(2));
-  EXPECT_EQ(bi.shape[2], static_cast<size_t>(3));
-  EXPECT_EQ(bi.strides.size(), 3U);  // 3-dimensional as d.
-  EXPECT_EQ(bi.strides[2], static_cast<size_t>(sizeof(ElemType)));
-  EXPECT_EQ(bi.strides[1], static_cast<size_t>(sizeof(ElemType) * 3));
-  EXPECT_EQ(bi.strides[0], static_cast<size_t>(sizeof(ElemType) * 2 * 3));
-}

python/paddle/fluid/dygraph/layers.py

@@ -291,9 +291,12 @@ class PyLayer(core.PyLayer):
             inputs = [inputs]
         ret = []
         for inp in inputs:
-            tensor = core.LoDTensor()
-            tensor.set(inp, core.CPUPlace())
-            ret.append(tensor)
+            if isinstance(inp, core.LoDTensor):
+                ret.append(inp)
+            else:
+                tensor = core.LoDTensor()
+                tensor.set(inp, core.CPUPlace())
+                ret.append(tensor)
         return tuple(ret)
 
     @staticmethod

python/paddle/fluid/tests/unittests/test_tensor_to_numpy.py

+# Copyright (c) 2019 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.
+
+import paddle.fluid as fluid
+import unittest
+import numpy as np
+import six
+
+
+class TensorToNumpyTest(unittest.TestCase):
+    def setUp(self):
+        self.shape = [11, 25, 32, 43]
+
+    def test_main(self):
+        dtypes = [
+            'float32', 'float64', 'int32', 'int64', 'uint8', 'int8', 'bool'
+        ]
+
+        places = [fluid.CPUPlace()]
+        if fluid.core.is_compiled_with_cuda():
+            places.append(fluid.CUDAPlace(0))
+            places.append(fluid.CUDAPinnedPlace())
+
+        for p in places:
+            for dtype in dtypes:
+                np_arr = np.reshape(
+                    np.array(six.moves.range(np.prod(self.shape))).astype(
+                        dtype), self.shape)
+
+                t = fluid.LoDTensor()
+                t.set(np_arr, p)
+
+                ret_np_arr = np.array(t)
+                self.assertEqual(np_arr.shape, ret_np_arr.shape)
+                self.assertEqual(np_arr.dtype, ret_np_arr.dtype)
+
+                all_equal = np.all(np_arr == ret_np_arr)
+                self.assertTrue(all_equal)
+
+
+if __name__ == '__main__':
+    unittest.main()