Implement a new totally dynamic (up to MAXPHYS) buffer kva allocation

scheme.  Additionally, add the capability for checking for unexpected
kernel page faults.  The maximum amount of kva space for buffers hasn't
been decreased from where it is, but it will now be possible to do so.

This scheme manages the kva space similar to the buffers themselves.  If
there isn't enough kva space because of usage or fragementation, buffers
will be reclaimed until a buffer allocation is successful.  This scheme
should be very resistant to fragmentation problems until/if the LFS code
is fixed and uses the bogus buffer locking scheme -- but a 'fixed' LFS
is not likely to use such a scheme.

Now there should be NO problem allocating buffers up to MAXPHYS.

1 files changed, 4 insertions, 3 deletions

diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
index fd04d87..40569ef 100644
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_map.h,v 1.14 1996/07/27 03:23:59 dyson Exp $
+ * $Id: vm_map.h,v 1.15 1996/07/30 03:08:11 dyson Exp $
  */
 
 /*
@@ -106,9 +106,9 @@ struct vm_map_entry {
 	vm_ooffset_t offset;		/* offset into object */
 	boolean_t is_a_map:1,		/* Is "object" a map? */
 	 is_sub_map:1,			/* Is "object" a submap? */
-	/* Only in sharing maps: */
 	 copy_on_write:1,		/* is data copy-on-write */
-	 needs_copy:1;			/* does object need to be copied */
+	 needs_copy:1,			/* does object need to be copied */
+	 nofault:1;			/* should never fault */
 	/* Only in task maps: */
 	vm_prot_t protection;		/* protection code */
 	vm_prot_t max_protection;	/* maximum protection */
@@ -208,6 +208,7 @@ typedef struct {
  */
 #define MAP_COPY_NEEDED 0x1
 #define MAP_COPY_ON_WRITE 0x2
+#define MAP_NOFAULT 0x4
 
 #ifdef KERNEL
 extern vm_offset_t kentry_data;