 @@ -1,108 +1,116 @@
-/*	$NetBSD: uvm_object.h,v 1.31 2011/06/12 03:36:03 rmind Exp $	*/
+/*	$NetBSD: uvm_object.h,v 1.32 2012/01/28 14:37:35 rmind Exp $	*/
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
  * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
  */
 #ifndef _UVM_UVM_OBJECT_H_
 #define _UVM_UVM_OBJECT_H_
 /*
  * uvm_object.h
  */
 #include <sys/queue.h>
 #include <sys/rbtree.h>
 #include <uvm/uvm_pglist.h>
 /*
- * uvm_object: all that is left of mach objects.
+ * The UVM memory object interface.  Notes:
+ *
  * A UVM memory object represents a list of pages, which are managed by
  * the object's pager operations (uvm_object::pgops).  All pages belonging
  * to an object are owned by it and thus protected by the object lock.
+ *
  * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
  * By default, the lock is allocated dynamically using mutex_obj(9) cache.
  * Lock sharing is normally used when there is an underlying object.  For
  * example, vnode representing a file may have an underlying node, which
  * is the case for tmpfs and layered file systems.  In such case, vnode's
  * UVM object and the underlying UVM object shares the lock (note that the
  * vnode_t::v_interlock points to uvm_object::vmobjlock).
  */
 struct uvm_object {
 	kmutex_t *		vmobjlock;	/* lock on memq */
 	const struct uvm_pagerops *pgops;	/* pager ops */
 	struct pglist		memq;		/* pages in this object */
 	int			uo_npages;	/* # of pages in memq */
 	unsigned		uo_refs;	/* reference count */
 	struct rb_tree		rb_tree;	/* tree of pages */
 	LIST_HEAD(,ubc_map)	uo_ubc;		/* ubc mappings */
 };
 /*
  * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
  * object is a kernel memory object rather than a normal one (kernel
  * memory objects don't have reference counts -- they never die).
+ *
  * this value is used to detected kernel object mappings at uvm_unmap()
  * time.   normally when an object is unmapped its pages eventaully become
  * deactivated and then paged out and/or freed.    this is not useful
  * for kernel objects... when a kernel object is unmapped we always want
  * to free the resources associated with the mapping.   UVM_OBJ_KERN
  * allows us to decide which type of unmapping we want to do.
  */
 #define UVM_OBJ_KERN		(-2)
 #define	UVM_OBJ_IS_KERN_OBJECT(uobj)					\
 	((uobj)->uo_refs == UVM_OBJ_KERN)
 #ifdef _KERNEL
 extern const struct uvm_pagerops uvm_vnodeops;
 extern const struct uvm_pagerops uvm_deviceops;
 extern const struct uvm_pagerops ubc_pager;
 extern const struct uvm_pagerops aobj_pager;
 #define	UVM_OBJ_IS_VNODE(uobj)						\
 	((uobj)->pgops == &uvm_vnodeops)
 #define	UVM_OBJ_IS_DEVICE(uobj)						\
 	((uobj)->pgops == &uvm_deviceops)
 #define	UVM_OBJ_IS_VTEXT(uobj)						\
 	(UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))
 #define	UVM_OBJ_IS_CLEAN(uobj)						\
 	(UVM_OBJ_IS_VNODE(uobj) && uvn_clean_p(uobj))
 /*
  * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.
  * (ie. wants to avoid writable user mappings.)
+ *
  * XXX bad name
  */
 #define	UVM_OBJ_NEEDS_WRITEFAULT(uobj)					\
 	(UVM_OBJ_IS_VNODE(uobj) && uvn_needs_writefault_p(uobj))
 #define	UVM_OBJ_IS_AOBJ(uobj)						\
 	((uobj)->pgops == &aobj_pager)
 extern const rb_tree_ops_t uvm_page_tree_ops;
 #endif /* _KERNEL */
 #endif /* _UVM_UVM_OBJECT_H_ */