Do you have customized codes as the (DeepStream v5 bug | NvDufSurface memory leakage) mentioned? If so, please upload your codes.
If you are using the original deepstream-app, DeepStream SDK FAQ - Intelligent Video Analytics / DeepStream SDK - NVIDIA Developer Forums can fix the known memory leak with deepstream 5.0.1. Or else, you need to tell us how to reproduce the problem with deepstream-app.