Fix cpplint errors with paddle/fluid/platform/gpu_info.* (#9710)

* Fix cpplint errors with paddle/fluid/platform/gpu_info.*

* Update

paddle/fluid/memory/memory.cc

@@ -95,7 +95,7 @@ void* Alloc<platform::CUDAPlace>(platform::CUDAPlace place, size_t size) {
     int cur_dev = platform::GetCurrentDeviceId();
     platform::SetDeviceId(place.device);
     size_t avail, total;
-    platform::GpuMemoryUsage(avail, total);
+    platform::GpuMemoryUsage(&avail, &total);
     LOG(WARNING) << "Cannot allocate " << size << " bytes in GPU "
                  << place.device << ", available " << avail << " bytes";
     LOG(WARNING) << "total " << total;

paddle/fluid/platform/gpu_info.cc

@@ -14,8 +14,9 @@ limitations under the License. */
 
 #include "paddle/fluid/platform/gpu_info.h"
 
-#include "gflags/gflags.h"
+#include <algorithm>
 
+#include "gflags/gflags.h"
 #include "paddle/fluid/platform/enforce.h"
 
 DEFINE_double(fraction_of_gpu_memory_to_use, 0.92,
@@ -77,8 +78,8 @@ void SetDeviceId(int id) {
                  "cudaSetDevice failed in paddle::platform::SetDeviceId");
 }
 
-void GpuMemoryUsage(size_t &available, size_t &total) {
-  PADDLE_ENFORCE(cudaMemGetInfo(&available, &total),
+void GpuMemoryUsage(size_t *available, size_t *total) {
+  PADDLE_ENFORCE(cudaMemGetInfo(available, total),
                  "cudaMemGetInfo failed in paddle::platform::GetMemoryUsage");
 }
 
@@ -86,7 +87,7 @@ size_t GpuMaxAllocSize() {
   size_t total = 0;
   size_t available = 0;
 
-  GpuMemoryUsage(available, total);
+  GpuMemoryUsage(&available, &total);
 
   // Reserve the rest for page tables, etc.
   return static_cast<size_t>(total * FLAGS_fraction_of_gpu_memory_to_use);
@@ -101,7 +102,7 @@ size_t GpuMaxChunkSize() {
   size_t total = 0;
   size_t available = 0;
 
-  GpuMemoryUsage(available, total);
+  GpuMemoryUsage(&available, &total);
   VLOG(10) << "GPU Usage " << available / 1024 / 1024 << "M/"
            << total / 1024 / 1024 << "M";
   size_t reserving = static_cast<size_t>(0.05 * total);

paddle/fluid/platform/gpu_info.h

@@ -24,8 +24,7 @@ namespace paddle {
 namespace platform {
 
 //! Environment variable: fraction of GPU memory to use on each device.
-const std::string kEnvFractionGpuMemoryToUse =
-    "PADDLE_FRACTION_GPU_MEMORY_TO_USE";
+const char kEnvFractionGpuMemoryToUse[] = "PADDLE_FRACTION_GPU_MEMORY_TO_USE";
 
 //! Get the total number of GPU devices in system.
 int GetCUDADeviceCount();
@@ -46,7 +45,7 @@ int GetCurrentDeviceId();
 void SetDeviceId(int device_id);
 
 //! Get the memory usage of current GPU device.
-void GpuMemoryUsage(size_t &available, size_t &total);
+void GpuMemoryUsage(size_t *available, size_t *total);
 
 //! Get the maximum allocation size of current GPU device.
 size_t GpuMaxAllocSize();