message: LOG the effect of TF_GPU_ALLOCATOR
  Just for diagnostic purposes.  LOG(INFO) seems fine because normally
  TF_GPU_ALLOCATOR won't be set.
diff: @@ -125,9 +125,11 @@ Allocator* GPUProcessState::GetGPUAllocator(const GPUOptions& options,
  // If true, checks for memory overwrites by writing
  // distinctive patterns on both ends of allocated memory.
  if (useCudaMemoryGuardAllocator()) {
  + LOG(INFO) << "Using memory guard allocator for GPU.";
  gpu_allocator = new GPUDebugAllocator(gpu_allocator, platform_gpu_id);
  gpu_allocator = new GPUNanResetAllocator(gpu_allocator, platform_gpu_id);
  } else if (useCudaMallocAllocator()) {
  + LOG(INFO) << "Using CUDA malloc allocator for GPU.";
  // If true, passes all allocation requests through to cudaMalloc
  // useful for doing memory debugging with tools like cuda-memcheck
  // **WARNING** probably will not work in a multi-gpu scenario
  