Make our v_usecount vnode reference count work identically to the

original BSD code.  The association between the vnode and the vm_object
no longer includes reference counts.  The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.

When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also.  The two "objects" are now
more intimately related, and so the interactions are now much less
complex.

When vnodes are now normally placed onto the free queue with an object still
attached.  The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code.  There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.

A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.

Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.

1 files changed, 6 insertions, 7 deletions

diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index a13a5bf..ac86c6c 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_object.h,v 1.39 1997/12/19 09:03:16 dyson Exp $
+ * $Id: vm_object.h,v 1.40 1997/12/29 00:24:55 dyson Exp $
  */
 
 /*
@@ -122,16 +122,13 @@ struct vm_object {
 /*
  * Flags
  */
-#define OBJ_CANPERSIST	0x0001		/* allow to persist */
 #define OBJ_ACTIVE	0x0004		/* active objects */
 #define OBJ_DEAD	0x0008		/* dead objects (during rundown) */
-#define	OBJ_PIPWNT	0x0040		/* paging in progress wanted */
+#define OBJ_PIPWNT	0x0040		/* paging in progress wanted */
 #define	OBJ_WRITEABLE	0x0080		/* object has been made writable */
-#define	OBJ_MIGHTBEDIRTY	0x0100	/* object might be dirty */
+#define OBJ_MIGHTBEDIRTY	0x0100	/* object might be dirty */
 #define OBJ_CLEANING	0x0200
-#define	OBJ_VFS_REF	0x0400		/* object is refed by vfs layer */
-#define OBJ_VNODE_GONE	0x0800		/* vnode is gone */
-#define OBJ_OPT		0x1000			/* I/O optimization */
+#define OBJ_OPT		0x1000		/* I/O optimization */
 
 #define OBJ_NORMAL	0x0		/* default behavior */
 #define OBJ_SEQUENTIAL	0x1		/* expect sequential accesses */
@@ -170,6 +167,8 @@ boolean_t vm_object_coalesce __P((vm_object_t, vm_pindex_t, vm_size_t, vm_size_t
 void vm_object_collapse __P((vm_object_t));
 void vm_object_copy __P((vm_object_t, vm_pindex_t, vm_object_t *, vm_pindex_t *, boolean_t *));
 void vm_object_deallocate __P((vm_object_t));
+void vm_object_terminate __P((vm_object_t));
+void vm_object_vndeallocate __P((vm_object_t));
 void vm_object_init __P((void));
 void vm_object_page_clean __P((vm_object_t, vm_pindex_t, vm_pindex_t, boolean_t));
 void vm_object_page_remove __P((vm_object_t, vm_pindex_t, vm_pindex_t, boolean_t));