Method set_size

dlib/cuda/gpu_data.cpp:165–246

    }

    void gpu_data::
    set_size(
        size_t new_size
    )
    {
        if (new_size == 0)
        {
            if (device_in_use)
            {
                // Wait for any possible CUDA kernels that might be using our memory block to
                // complete before we free the memory.
                synchronize_stream(0);
                device_in_use = false;
            }
            wait_for_transfer_to_finish();
            data_size = 0;
            host_current = true;
            device_current = true;
            device_in_use = false;
            data_host.reset();
            data_device.reset();
        }
        else if (new_size != data_size)
        {
            if (device_in_use)
            {
                // Wait for any possible CUDA kernels that might be using our memory block to
                // complete before we free the memory.
                synchronize_stream(0);
                device_in_use = false;
            }
            wait_for_transfer_to_finish();
            data_size = new_size;
            host_current = true;
            device_current = true;
            device_in_use = false;

            try
            {
                CHECK_CUDA(cudaGetDevice(&the_device_id));

                // free memory blocks before we allocate new ones.
                data_host.reset();
                data_device.reset();

                void* data;
                CHECK_CUDA(cudaMallocHost(&data, new_size*sizeof(float)));
                // Note that we don't throw exceptions since the free calls are invariably
                // called in destructors.  They also shouldn't fail anyway unless someone
                // is resetting the GPU card in the middle of their program.
                data_host.reset((float*)data, [](float* ptr){
                    auto err = cudaFreeHost(ptr);
                    if(err!=cudaSuccess)
                        std::cerr << "cudaFreeHost() failed. Reason: " << cudaGetErrorString(err) << std::endl;
                });

                CHECK_CUDA(cudaMalloc(&data, new_size*sizeof(float)));
                data_device.reset((float*)data, [](float* ptr){