The current default for RLIMIT_MLOCK is set to 64 KiB. This is not much! This limit was set to this value in 2008 at the request of GnuPG. I understand that the main audience of io_uring is high-performance servers and such, where configuring the rlimits appropriately is not a particularly burdensome ask. However, this dramatically limits the utility of IORING_REGISTER_BUFFERS in the end-user software use-case, almost such that it's entirely pointless *without* raising the mlock rlimit. I wonder if we can/should make a case for raising the default rlimit to something more useful for $CURRENTYEAR?
