remove unused code (#5219)

* remove unused code

* fix cmake file

* fix build error

Author: QiJune

paddle/platform/CMakeLists.txt

@@ -9,7 +9,6 @@ cc_test(place_test SRCS place_test.cc DEPS place glog gflags)
 add_subdirectory(dynload)
 
 cc_test(enforce_test SRCS enforce_test.cc DEPS stringpiece)
-cc_test(environment_test SRCS environment_test.cc DEPS stringpiece)
 
 IF(WITH_GPU)
     set(GPU_CTX_DEPS dynload_cuda dynamic_loader)

paddle/platform/environment.h

@@ -17,7 +17,6 @@ limitations under the License. */
 #include "gflags/gflags.h"
 
 #include "paddle/platform/enforce.h"
-#include "paddle/platform/environment.h"
 
 DEFINE_double(fraction_of_gpu_memory_to_use, 0.95,
               "Default use 95% of GPU memory for PaddlePaddle,"
@@ -75,13 +74,6 @@ size_t GpuMaxChunkSize() {
 
   GpuMemoryUsage(available, total);
 
-  if (IsEnvVarDefined(kEnvFractionGpuMemoryToUse)) {
-    auto val = std::stod(GetEnvValue(kEnvFractionGpuMemoryToUse));
-    PADDLE_ENFORCE_GT(val, 0.0);
-    PADDLE_ENFORCE_LE(val, 1.0);
-    FLAGS_fraction_of_gpu_memory_to_use = val;
-  }
-
   // Reserving the rest memory for page tables, etc.
   size_t reserving = (1 - FLAGS_fraction_of_gpu_memory_to_use) * total;