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uvm_object.h revision 1.32 
      1 /*	$NetBSD: uvm_object.h,v 1.32 2012/01/28 14:37:35 rmind Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997 Charles D. Cranor and Washington University.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  *
     27  * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
     28  */
     29 
     30 #ifndef _UVM_UVM_OBJECT_H_
     31 #define _UVM_UVM_OBJECT_H_
     32 
     33 #include <sys/queue.h>
     34 #include <sys/rbtree.h>
     35 #include <uvm/uvm_pglist.h>
     36 
     37 /*
     38  * The UVM memory object interface.  Notes:
     39  *
     40  * A UVM memory object represents a list of pages, which are managed by
     41  * the object's pager operations (uvm_object::pgops).  All pages belonging
     42  * to an object are owned by it and thus protected by the object lock.
     43  *
     44  * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
     45  * By default, the lock is allocated dynamically using mutex_obj(9) cache.
     46  * Lock sharing is normally used when there is an underlying object.  For
     47  * example, vnode representing a file may have an underlying node, which
     48  * is the case for tmpfs and layered file systems.  In such case, vnode's
     49  * UVM object and the underlying UVM object shares the lock (note that the
     50  * vnode_t::v_interlock points to uvm_object::vmobjlock).
     51  */
     52 
     53 struct uvm_object {
     54 	kmutex_t *		vmobjlock;	/* lock on memq */
     55 	const struct uvm_pagerops *pgops;	/* pager ops */
     56 	struct pglist		memq;		/* pages in this object */
     57 	int			uo_npages;	/* # of pages in memq */
     58 	unsigned		uo_refs;	/* reference count */
     59 	struct rb_tree		rb_tree;	/* tree of pages */
     60 	LIST_HEAD(,ubc_map)	uo_ubc;		/* ubc mappings */
     61 };
     62 
     63 /*
     64  * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
     65  * object is a kernel memory object rather than a normal one (kernel
     66  * memory objects don't have reference counts -- they never die).
     67  *
     68  * this value is used to detected kernel object mappings at uvm_unmap()
     69  * time.   normally when an object is unmapped its pages eventaully become
     70  * deactivated and then paged out and/or freed.    this is not useful
     71  * for kernel objects... when a kernel object is unmapped we always want
     72  * to free the resources associated with the mapping.   UVM_OBJ_KERN
     73  * allows us to decide which type of unmapping we want to do.
     74  */
     75 #define UVM_OBJ_KERN		(-2)
     76 
     77 #define	UVM_OBJ_IS_KERN_OBJECT(uobj)					\
     78 	((uobj)->uo_refs == UVM_OBJ_KERN)
     79 
     80 #ifdef _KERNEL
     81 
     82 extern const struct uvm_pagerops uvm_vnodeops;
     83 extern const struct uvm_pagerops uvm_deviceops;
     84 extern const struct uvm_pagerops ubc_pager;
     85 extern const struct uvm_pagerops aobj_pager;
     86 
     87 #define	UVM_OBJ_IS_VNODE(uobj)						\
     88 	((uobj)->pgops == &uvm_vnodeops)
     89 
     90 #define	UVM_OBJ_IS_DEVICE(uobj)						\
     91 	((uobj)->pgops == &uvm_deviceops)
     92 
     93 #define	UVM_OBJ_IS_VTEXT(uobj)						\
     94 	(UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))
     95 
     96 #define	UVM_OBJ_IS_CLEAN(uobj)						\
     97 	(UVM_OBJ_IS_VNODE(uobj) && uvn_clean_p(uobj))
     98 
     99 /*
    100  * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.
    101  * (ie. wants to avoid writable user mappings.)
    102  *
    103  * XXX bad name
    104  */
    105 
    106 #define	UVM_OBJ_NEEDS_WRITEFAULT(uobj)					\
    107 	(UVM_OBJ_IS_VNODE(uobj) && uvn_needs_writefault_p(uobj))
    108 
    109 #define	UVM_OBJ_IS_AOBJ(uobj)						\
    110 	((uobj)->pgops == &aobj_pager)
    111 
    112 extern const rb_tree_ops_t uvm_page_tree_ops;
    113 
    114 #endif /* _KERNEL */
    115 
    116 #endif /* _UVM_UVM_OBJECT_H_ */
    117