Merge pull request #15496 from sneaxiy/lazy_allocator2

Fix bug when user set CUDA_VISIBLE_DEVICES be empty and run CPU-only models

paddle/fluid/platform/gpu_info.cc

@@ -15,6 +15,8 @@ limitations under the License. */
 #include "paddle/fluid/platform/gpu_info.h"
 
 #include <algorithm>
+#include <cstdlib>
+#include <string>
 
 #include "gflags/gflags.h"
 #include "paddle/fluid/platform/enforce.h"
@@ -58,7 +60,18 @@ DEFINE_string(selected_gpus, "",
 namespace paddle {
 namespace platform {
 
-int GetCUDADeviceCount() {
+static int GetCUDADeviceCountImpl() {
+  const auto *cuda_visible_devices = std::getenv("CUDA_VISIBLE_DEVICES");
+  if (cuda_visible_devices != nullptr) {
+    std::string cuda_visible_devices_str(cuda_visible_devices);
+    if (std::all_of(cuda_visible_devices_str.begin(),
+                    cuda_visible_devices_str.end(),
+                    [](char ch) { return ch == ' '; })) {
+      VLOG(2) << "CUDA_VISIBLE_DEVICES is set to be empty. No GPU detected.";
+      return 0;
+    }
+  }
+
   int count;
   PADDLE_ENFORCE(
       cudaGetDeviceCount(&count),
@@ -66,6 +79,11 @@ int GetCUDADeviceCount() {
   return count;
 }
 
+int GetCUDADeviceCount() {
+  static auto dev_cnt = GetCUDADeviceCountImpl();
+  return dev_cnt;
+}
+
 int GetCUDAComputeCapability(int id) {
   PADDLE_ENFORCE_LT(id, GetCUDADeviceCount(), "id must less than GPU count");
   cudaDeviceProp device_prop;

paddle/fluid/pybind/pybind.cc

@@ -642,7 +642,18 @@ All parameter, weight, gradient are variables in Paddle.
   py::class_<platform::Communicator>(m, "Communicator").def(py::init<>());
 #endif
   py::class_<platform::CUDAPlace>(m, "CUDAPlace")
-      .def(py::init<int>())
+      .def("__init__",
+           [](platform::CUDAPlace &self, int dev_id) {
+#ifdef PADDLE_WITH_CUDA
+             PADDLE_ENFORCE(
+                 dev_id >= 0 && dev_id < platform::GetCUDADeviceCount(),
+                 "Invalid CUDAPlace(%d), must inside [0, %d)", dev_id,
+                 platform::GetCUDADeviceCount());
+             new (&self) platform::CUDAPlace(dev_id);
+#else
+             PADDLE_THROW("Cannot use CUDAPlace in CPU only version");
+#endif
+           })
       .def("__str__", string::to_string<const platform::CUDAPlace &>);
 
   py::class_<paddle::platform::CPUPlace>(m, "CPUPlace")
@@ -650,7 +661,12 @@ All parameter, weight, gradient are variables in Paddle.
       .def("__str__", string::to_string<const platform::CPUPlace &>);
 
   py::class_<paddle::platform::CUDAPinnedPlace>(m, "CUDAPinnedPlace")
-      .def(py::init<>())
+      .def("__init__",
+           [](platform::CUDAPinnedPlace &) {
+#ifndef PADDLE_WITH_CUDA
+             PADDLE_THROW("Cannot use CUDAPinnedPlace in CPU only version");
+#endif
+           })
       .def("__str__", string::to_string<const platform::CUDAPinnedPlace &>);
 
   py::class_<platform::Place>(m, "Place")