mtx_trylock() on a spin mutex

[John Baldwin]

On Tuesday, January 31, 2012 6:35:08 am dmitry.krivenok at emc.com wrote:
> Hello,
> Could someone please explain why mtx_trylock() must not be called on a spin mutex?
> Is it conceptually wrong or is it a restriction of FreeBSD kernel implementation?

The current mutex API generally uses different methods for the different types of
mutexes (at some point I may split spin locks out into a completely separate
API to simplify things).  If we wanted to do trylocks on spinlocks, then a new
mtx_trylock_spin() method would be added as you've done.  To date we haven't had
any use cases for trylock operations on a spin lock.  Even try locks on other
locking primitives are used fairly rarely.

-- 
John Baldwin