The OpenBSD paragraph in the "Shared Memory and Semaphores” section seems to
have been slightly incorrect since around 2002. The kern.ipc.shm_use_phys
sysctl setting has never existed in OpenBSD (it is in NetBSD and FreeBSD) and
SEMMAP is not a kernel configuration option. Further, there is no kernel
config for locking shared memory into RAM so the whole paragraph is best
removed it seems. I believe this is an artifact from FreeBSD and OpenBSD
sharing a paragraph, which was split into separate ones a long time ago.
The attached patch removes the above mentioned parts (confirmed with an OpenBSD
developer). This should probably be backpatched to all supported versions as
it’s been wrong for a long time.
cheers ./daniel