not there is an audit record hung off of td_ar on the current thread.
Test this flag instead of td_ar when auditing syscall arguments or
checking for an audit record to commit on syscall return. Under
these circumstances, td_pflags is much more likely to be in the cache
(especially if there is no auditing of the current system call), so
this should help reduce cache misses in the system call return path.
MFC after: 1 week
Reported by: kris
Obtained from: TrustedBSD Project
b3f468e253