git: kernel -- vm_object locking: DEBUG_LOCKS check for hold_wait vs hold deadlock

[Matthew Dillon]

:    If a thread has a hold on a vm_object and enters hold_wait (via either
:    vm_object_terminate or vm_object_collapse), it will wait forever for the hold
:    count to hit 0. Record the threads holding an object in a per-object array.
:
:http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/cb443cbb47dab690574674c82ee9407c28deb544

    Hmm.  That's a bit iffy, it is possible for there to be more than 32
    holds on a VM object.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>