vm_radix.h revision 230750 
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#include <sys/queue.h>
33
34/* Default values of the tree parameters */
35#define	VM_RADIX_WIDTH	5
36#define	VM_RADIX_COUNT	(1 << VM_RADIX_WIDTH)
37#define	VM_RADIX_MASK	(VM_RADIX_COUNT - 1)
38#define	VM_RADIX_MAXVAL	((vm_pindex_t)-1)
39#define	VM_RADIX_LIMIT	howmany((sizeof(vm_pindex_t) * NBBY), VM_RADIX_WIDTH)
40#define	VM_RADIX_FLAGS	0x3	/* Flag bits stored in node pointers. */
41#define	VM_RADIX_BLACK	0x1	/* Black node. (leaf only) */
42#define	VM_RADIX_RED	0x2	/* Red node. (leaf only) */
43#define	VM_RADIX_ANY	(VM_RADIX_RED | VM_RADIX_BLACK)
44#define	VM_RADIX_EMPTY	0x1	/* Empty hint. (internal only) */
45#define	VM_RADIX_HEIGHT	0xf	/* Bits of height in root */
46#define	VM_RADIX_STACK	8	/* Nodes to store on stack. */
47
48/* Calculates maximum value for a tree of height h. */
49#define	VM_RADIX_MAX(h)							\
50	    ((h) == VM_RADIX_LIMIT ? VM_RADIX_MAXVAL :			\
51	    (((vm_pindex_t)1 << ((h) * VM_RADIX_WIDTH)) - 1))
52
53/*
54 * Radix tree root.  The height and pointer are set together to permit
55 * coherent lookups while the root is modified.
56 */
57struct vm_radix {
58	uintptr_t	rt_root;		/* root + height */
59};
60
61#ifdef _KERNEL
62CTASSERT(VM_RADIX_HEIGHT >= VM_RADIX_LIMIT);
63
64struct vm_radix_node {
65	void		*rn_child[VM_RADIX_COUNT];	/* Child nodes. */
66    	volatile uint32_t rn_count;			/* Valid children. */
67};
68
69void	vm_radix_init(void);
70
71/*
72 * Functions which only work with black nodes. (object lock)
73 */
74int 	vm_radix_insert(struct vm_radix *, vm_pindex_t, void *);
75void 	vm_radix_shrink(struct vm_radix *);
76
77/*
78 * Functions which work on specified colors. (object, vm_page_queue_free locks)
79 */
80void	*vm_radix_color(struct vm_radix *, vm_pindex_t, int);
81void	*vm_radix_lookup(struct vm_radix *, vm_pindex_t, int);
82int	vm_radix_lookupn(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
83	    void **, int, vm_pindex_t *);
84void	*vm_radix_lookup_le(struct vm_radix *, vm_pindex_t, int);
85void	vm_radix_reclaim_allnodes(struct vm_radix *);
86void	*vm_radix_remove(struct vm_radix *, vm_pindex_t, int);
87void	vm_radix_foreach(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
88	    void (*)(void *));
89
90/*
91 * Look up any entry at a position greater or equal to index.
92 */
93static inline void *
94vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index, int color)
95{
96        void *val;
97
98        if (vm_radix_lookupn(rtree, index, 0, color, &val, 1, &index))
99                return (val);
100        return (NULL);
101}
102
103static inline void *
104vm_radix_last(struct vm_radix *rtree, int color)
105{
106
107	return vm_radix_lookup_le(rtree, 0, color);
108}
109
110static inline void *
111vm_radix_first(struct vm_radix *rtree, int color)
112{
113
114	return vm_radix_lookup_ge(rtree, 0, color);
115}
116
117static inline void *
118vm_radix_next(struct vm_radix *rtree, vm_pindex_t index, int color)
119{
120
121	if (index == -1)
122		return (NULL);
123	return vm_radix_lookup_ge(rtree, index + 1, color);
124}
125
126static inline void *
127vm_radix_prev(struct vm_radix *rtree, vm_pindex_t index, int color)
128{
129
130	if (index == 0)
131		return (NULL);
132	return vm_radix_lookup_le(rtree, index - 1, color);
133}
134
135#endif /* _KERNEL */
136#endif /* !_VM_RADIX_H_ */
137