Merge from vmc-playground branch:

Replace the sub-optimal uma_zone_set_obj() primitive with more modern
uma_zone_reserve_kva().  The new primitive reserves before hand
the necessary KVA space to cater the zone allocations and allocates pages
with ALLOC_NOOBJ.  More specifically:
- uma_zone_reserve_kva() does not need an object to cater the backend
  allocator.
- uma_zone_reserve_kva() can cater M_WAITOK requests, in order to
  serve zones which need to do uma_prealloc() too.
- When possible, uma_zone_reserve_kva() uses directly the direct-mapping
  by uma_small_alloc() rather than relying on the KVA / offset
  combination.

The removal of the object attribute allows 2 further changes:
1) _vm_object_allocate() becomes static within vm_object.c
2) VM_OBJECT_LOCK_INIT() is removed.  This function is replaced by
   direct calls to mtx_init() as there is no need to export it anymore
   and the calls aren't either homogeneous anymore: there are now small
   differences between arguments passed to mtx_init().

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc (which also offered almost all the comments)
Tested by:	pho, jhb, davide

1 files changed, 9 insertions, 10 deletions

diff --git a/sys/vm/uma.h b/sys/vm/uma.h
index 3abfd3e..2569b88 100644
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -432,24 +432,23 @@ void uma_reclaim(void);
 void uma_set_align(int align);
 
 /*
- * Switches the backing object of a zone
+ * Reserves the maximum KVA space required by the zone and configures the zone
+ * to use a VM_ALLOC_NOOBJ-based backend allocator.
  *
  * Arguments:
  *	zone  The zone to update.
- *	obj   The VM object to use for future allocations.
- *	size  The size of the object to allocate.
+ *	nitems  The upper limit on the number of items that can be allocated.
  *
  * Returns:
- *	0  if kva space can not be allocated
+ *	0  if KVA space can not be allocated
  *	1  if successful
  *
  * Discussion:
- *	A NULL object can be used and uma will allocate one for you.  Setting
- *	the size will limit the amount of memory allocated to this zone.
- *
+ *	When the machine supports a direct map and the zone's items are smaller
+ *	than a page, the zone will use the direct map instead of allocating KVA
+ *	space.
  */
-struct vm_object;
-int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
+int uma_zone_reserve_kva(uma_zone_t zone, int nitems);
 
 /*
  * Sets a high limit on the number of items allowed in a zone
@@ -521,7 +520,7 @@ void uma_zone_set_zinit(uma_zone_t zone, uma_init zinit);
 void uma_zone_set_zfini(uma_zone_t zone, uma_fini zfini);
 
 /*
- * Replaces the standard page_alloc or obj_alloc functions for this zone
+ * Replaces the standard backend allocator for this zone.
  *
  * Arguments:
  *	zone   The zone whose backend allocator is being changed.