proto: struct thread *td, struct swapon_args *uap
parms: td, uap
errors:
  - ENOTDIR
  - ENAMETOOLONG
  - ENOENT
  - EACCES
  - ELOOP
  - EPERM
  - EFAULT
  - ENOTBLK
  - EBUSY
  - ENXIO
  - EIO
profiles:
  - mem
