AF_XDP - why setrlimit() ?

Hi,

The sample xdpsock_user.c program does a setrlimit(RLIMIT_MEMLOCK) but
subsequently doesn't do a mlock or pass MAP_LOCKED flag to mmap().
Same with xdp-tutorial which has the following comment but I don't see
any locking happening anywhere in the code.

/* Allow unlimited locking of memory, so all memory needed for packet
* buffers can be locked.
*/

What is the purpose behind this setrlimit? Does the libbpf/xdp library
do a mlock internally?

I came to know that BPF maps need the setrlimit and I assume the xsk
APIs create a XSK map internally - so is that the only reason?

Didn't find any references to setrlimit in
https://www.kernel.org/doc/html/latest/networking/af_xdp.html either.

Srivats