* Add a "how" argument to uma_zone constructors and initialization functions

  so that they know whether the allocation is supposed to be able to sleep
  or not.
* Allow uma_zone constructors and initialation functions to return either
  success or error.  Almost all of the ones in the tree currently return
  success unconditionally, but mbuf is a notable exception: the packet
  zone constructor wants to be able to fail if it cannot suballocate an
  mbuf cluster, and the mbuf allocators want to be able to fail in general
  in a MAC kernel if the MAC mbuf initializer fails.  This fixes the
  panics people are seeing when they run out of memory for mbuf clusters.
* Allow debug.nosleepwithlocks on WITNESS to be disabled, without changing
  the default.

Both bmilekic and jeff have reviewed the changes made to make failable
zone allocations work.

1 files changed, 8 insertions, 4 deletions

diff --git a/sys/vm/uma.h b/sys/vm/uma.h
index ff7975d..bcfb5bb 100644
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -54,15 +54,17 @@ typedef struct uma_zone * uma_zone_t;
  *	item  A pointer to the memory which has been allocated.
  *	arg   The arg field passed to uma_zalloc_arg
  *	size  The size of the allocated item
+ *	flags See zalloc flags
  * 
  * Returns:
- *	Nothing
+ *	0      on success
+ *      errno  on failure
  *
  * Discussion:
  *	The constructor is called just before the memory is returned
  *	to the user. It may block if necessary.
  */
-typedef void (*uma_ctor)(void *mem, int size, void *arg);
+typedef int (*uma_ctor)(void *mem, int size, void *arg, int flags);
 
 /*
  * Item destructor
@@ -88,15 +90,17 @@ typedef void (*uma_dtor)(void *mem, int size, void *arg);
  * Arguments:
  *	item  A pointer to the memory which has been allocated.
  *	size  The size of the item being initialized.
+ *	flags See zalloc flags
  * 
  * Returns:
- *	Nothing
+ *	0      on success
+ *      errno  on failure
  *
  * Discussion:
  *	The initializer is called when the memory is cached in the uma zone. 
  *	this should be the same state that the destructor leaves the object in.
  */
-typedef void (*uma_init)(void *mem, int size);
+typedef int (*uma_init)(void *mem, int size, int flags);
 
 /*
  * Item discard function