From onload-201710 onwards, the sizes of Onload Control Plane tables are set by parameters for the onload_cp_server process. These are listed in Parameters for onload_cp_server.
If non-default values are needed, the user should create a file in the /etc/modprobe.d directory. The file must have the .conf extension. The onload_cp_server parameters can be added to the file in a single line, space-separated, in the following format:
options onload cplane_server_params="--mac-max=512 --fwd-max=256"