Upon further inspection, this is actually fixed in systemd 241. To reproduce, try setting a LimitMEMLOCK higher than 64mb for the system unit user@.service, OR for any unit executed by a systemd --user process. You will see that the RLIMIT_MEMLOCK is actually clamped to 64MB. This can be observed by using prlimit -p <<any-process-id-inside-or-spawned-by-such-a-unit>>.
You can reproduce by trying to give a user session (via user@.service OR /etc/systemd/user.conf) a LimitMEMLOCK of greater than 64MB and then inside a systemd unit or inside a gnome-terminal (since gnome terminals in at least disco and newer are run under a systemd user-service) try to execute `jackd -d hw:0 -r 48000 -p 256 -n 3 -S`. You may need to suspend/stop pulseadio.
On my system at least (USB audio only), jackd wants to memlock 82280346 bytes (82MBish) of RAM for audio buffers and the like.
Upon further inspection, this is actually fixed in systemd 241. To reproduce, try setting a LimitMEMLOCK higher than 64mb for the system unit user@.service, OR for any unit executed by a systemd --user process. You will see that the RLIMIT_MEMLOCK is actually clamped to 64MB. This can be observed by using prlimit -p <<any-process- id-inside- or-spawned- by-such- a-unit> >.
You can reproduce by trying to give a user session (via user@.service OR /etc/systemd/ user.conf) a LimitMEMLOCK of greater than 64MB and then inside a systemd unit or inside a gnome-terminal (since gnome terminals in at least disco and newer are run under a systemd user-service) try to execute `jackd -d hw:0 -r 48000 -p 256 -n 3 -S`. You may need to suspend/stop pulseadio.
On my system at least (USB audio only), jackd wants to memlock 82280346 bytes (82MBish) of RAM for audio buffers and the like.