vm_radix.h revision 238245 
1/*
2 * Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org>
3 * Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29#ifndef _VM_RADIX_H_
30#define _VM_RADIX_H_
31
32#define	VM_RADIX_STACK	8	/* Nodes to store on stack. */
33
34/*
35 * Radix tree root.  The height and pointer are set together to permit
36 * coherent lookups while the root is modified.
37 */
38struct vm_radix {
39	uintptr_t	rt_root;		/* root + height */
40};
41
42#ifdef _KERNEL
43
44void	vm_radix_init(void);
45int 	vm_radix_insert(struct vm_radix *, vm_pindex_t, void *);
46void	*vm_radix_lookup(struct vm_radix *, vm_pindex_t);
47int	vm_radix_lookupn(struct vm_radix *, vm_pindex_t, vm_pindex_t, void **,
48	    int, vm_pindex_t *, u_int *);
49void	*vm_radix_lookup_le(struct vm_radix *, vm_pindex_t);
50void	vm_radix_reclaim_allnodes(struct vm_radix *);
51void	vm_radix_remove(struct vm_radix *, vm_pindex_t);
52
53/*
54 * Look up any entry at a position greater or equal to index.
55 */
56static inline void *
57vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
58{
59        void *val;
60	u_int dummy;
61
62        if (vm_radix_lookupn(rtree, index, 0, &val, 1, &index, &dummy))
63                return (val);
64        return (NULL);
65}
66
67static inline void *
68vm_radix_last(struct vm_radix *rtree)
69{
70
71	return vm_radix_lookup_le(rtree, 0);
72}
73
74static inline void *
75vm_radix_first(struct vm_radix *rtree)
76{
77
78	return vm_radix_lookup_ge(rtree, 0);
79}
80
81static inline void *
82vm_radix_next(struct vm_radix *rtree, vm_pindex_t index)
83{
84
85	if (index == -1)
86		return (NULL);
87	return vm_radix_lookup_ge(rtree, index + 1);
88}
89
90static inline void *
91vm_radix_prev(struct vm_radix *rtree, vm_pindex_t index)
92{
93
94	if (index == 0)
95		return (NULL);
96	return vm_radix_lookup_le(rtree, index - 1);
97}
98
99#endif /* _KERNEL */
100#endif /* !_VM_RADIX_H_ */
101