Disposal of a misleading M_TRYWAIT

[Ruslan Ermilov]

I'd like to remove the misleading uses of M_TRYWAIT throughout
the tree and clean up some dead code that assumes its original
behavior (that it could return NULL).

Since the advent of MBUMA in FreeBSD (whatever), M_TRYWAIT has
meant M_WAITOK.  (The reason for M_TRYWAIT itself was that an
original mbuf's M_WAIT could return NULL.)

There is little or no sign that this will change, and there are
lots of consumers that already pass M_WAITOK to mbuf allocator
routines and rely on its invariants, so support for the concept
of M_TRYWAIT has rotted and would have to be re-written anyway
if reintroduced.

http://people.freebsd.org/~ru/patches/M_TRYWAIT.patch


Cheers,
-- 
Ruslan Ermilov
ru at FreeBSD.org
FreeBSD committer