osfmk/vm/vm_object.c

161  *	Each object also records the memory object reference
301  *	The routines that acquire a reference to a virtual
306  *	from the reference mechanism, so that the lock need
799 	 * Create an "extra" reference to this object so that we never
886  *	Release a reference to the specified object,
931 		 * This "named" object's reference count is about to
939 		 * This internal object's reference count is about to
951 		 * kept alive solely by the reference we're about to release.
952 		 * Let's try and release our reference without taking
1014 		 *	If the object has a named reference, and only
1015 		 *	that reference would remain, inform the pager
1016 		 *	about the last "mapping" reference going away.
1038 		 *	Lose the reference. If other references
1041 		 *	If it is the last reference, then keep it
1057 				 * There's only one reference left on this
1069 				 * don't know if this last reference on it is
1114 			 *	Now it is safe to decrement reference count,
1115 			 *	and to return if reference count is > 0.
1230 			 *	but maintain a "paging reference" rather than
1231 			 *	a normal reference.
1288 				if (p->reference == FALSE || p->dirty == FALSE) {
1293 						p->reference = TRUE;
1303 						p->reference = TRUE;
1312 			if (p->inactive && p->reference == TRUE) {
1545 				p->reference = FALSE;
1682 		 *	Take a reference to avoid recursive deallocations.
1694 		 *	maintain a "paging reference" rather than a normal
1695 		 *	reference.
1721  *		and the object must have exactly one reference.
1723  *		The shadow object reference is left alone.
1764 	 * Did somebody get a reference to the object while we were
1795 	 *	copy. The reference we hold on the shadow must be dropped
1814 		 * they may also need to acquire a reference on the VM object,
1816 		 * they may end up releasing the last reference on the VM
1834 		 * object's reference on its shadow object yet.
1851 	 * reference on it.
1852 	 * The caller is responsible for dropping that reference.
1995 	 * release our reference to it here.
2341 			 * Drop the reference "object" was holding on
2392  *			release our last reference to it.
2418 	 *	Release reference to pager.
2483 		 * JMM - Release the caller's reference.  This assumes the
2484 		 * caller had a reference to release, which is a big (but
2486 		 * vnode pager (it is holding a named reference when making
2677 		 * We're already holding a "paging in progress" reference
3385  *		The caller must hold a reference and a lock
3439 	 *		 this routine, since we have the only reference.
3609 	 *	Lose the extra reference, and return our object.
3662 		 *	Make another reference to the object.
3830  *		on exit - so the caller must also hold a reference to it.
3954 			 *	Return another reference to
4263  *	object reference is deallocated.
4330 	 *	a reference to it.  Our caller changes his reference
4331 	 *	to point to the new object, removing a reference to
4332 	 *	the source object.  Net result: no change of reference
4365  *			a port reference;
4423  *	During various paging operations, the pager reference found in the
4594 		 *	Copy the reference we were given.
4690 	 *	Prevent collapse or termination by holding a paging reference
4746 		/* acquire a reference for the default memory manager */
4768 	 *	A reference was returned by
4777 	 *	Drop the reference we were passed.
4784 	 *	Release the paging reference
4801 	 *	Prevent collapse or termination by holding a paging reference
4870 	 *	A reference was returned by
4882 	 *	Drop the reference we were passed.
4889 	 *	Release the paging reference
5226 	 *	Note that the reference to backing_object->shadow
5306 	 *	Do object reference in-line to
5343 	 *	Drop the reference count on backing_object.
5385 			/* XXX get a reference for the deallocate below */
5392 		 * valid reference is held on the object... w/o a valid
5393 		 * reference, it is unsafe and unwise (you will definitely
5396 		 * The "activity_in_progress" reference will keep the object
5582 		 *	object (if the parent is the only reference to
5583 		 *	it) or (perhaps) remove the parent's reference
5586 		 *	If there is exactly one reference to the backing
5980  *		prev_size	Size of reference to prev_object
5981  *		next_size	Size of reference to next_object
5985  *	to preserve the reference to the object(s).
6026 	 *	. more than one reference
6279 			*	(implicit) reference. Take a reference to avoid
6293 		 	*	maintain a "paging reference" rather
6294 			*	than a normal reference.
6365  *		Attempt to recover a named reference for a VM object.
6370  *		KERN_SUCCESS - we recovered a named reference on the object
6371  *		KERN_FAILURE - we could not recover a reference (object dead)
6439  *	Enforces name semantic on memory_object reference count decrement
6441  *	reference gained through the memory_object_create_named.
6444  *	reference count is not 1. i.e. idle with the only remaining reference
6447  *	false and the reference count is decremented.  If the RESPECT_CACHE
6448  *	flag is set and the reference count has gone to zero, the
6450  *	the reference count is zero, it is simply terminated.
6570 	 *	Lock the object, and acquire a paging reference to
6571 	 *	prevent the memory_object reference from being released.
6707  * special semantics when its reference count is exactly 1.  If its reference
7274  *	Gets another reference to the given object.
7392 	 * taking a "paging_in_progress" reference wouldn't be enough