On Wed, 15 Jun 2016, Peter Zijlstra wrote:

Yeah, see a few patches further in this series, where he guards a
variables with the osq_lock.

So one problem I have with all this is that if we are hardening osq_lock/unlock()
because of some future use that is specific to rwsems, then we will immediately
be hurting mutexes for no good reason.

Thanks,
Davidlohr