vm_radix.h revision 228312 
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_LIMIT	howmany((sizeof(vm_pindex_t) * NBBY), VM_RADIX_WIDTH)
39#define	VM_RADIX_FLAGS	0x3	/* Flag bits stored in node pointers. */
40#define	VM_RADIX_BLACK	0x1	/* Black node. (leaf only) */
41#define	VM_RADIX_RED	0x2	/* Red node. (leaf only) */
42#define	VM_RADIX_ANY	(VM_RADIX_RED | VM_RADIX_BLACK)
43#define	VM_RADIX_EMPTY	0x1	/* Empty hint. (internal only) */
44#define	VM_RADIX_HEIGHT	0xf	/* Bits of height in root */
45#define	VM_RADIX_STACK	8	/* Nodes to store on stack. */
46
47/* Calculates maximum value for a tree of height h. */
48#define	VM_RADIX_MAX(h)							\
49	    ((h) == VM_RADIX_LIMIT ? ((vm_pindex_t)-1) :		\
50	    (((vm_pindex_t)1 << ((h) * VM_RADIX_WIDTH)) - 1))
51
52/*
53 * Radix tree root.  The height and pointer are set together to permit
54 * coherent lookups while the root is modified.
55 */
56struct vm_radix {
57	uintptr_t	rt_root;		/* root + height */
58};
59
60#ifdef _KERNEL
61CTASSERT(VM_RADIX_HEIGHT >= VM_RADIX_LIMIT);
62
63struct vm_radix_node {
64	void		*rn_child[VM_RADIX_COUNT];	/* Child nodes. */
65    	uint32_t	 rn_count;			/* Valid children. */
66};
67
68void	vm_radix_init(void);
69
70/*
71 * Functions which only work with black nodes. (object lock)
72 */
73int 	vm_radix_insert(struct vm_radix *, vm_pindex_t, void *);
74void 	vm_radix_shrink(struct vm_radix *);
75
76/*
77 * Functions which work on specified colors. (object, vm_page_queue_free locks)
78 */
79void	*vm_radix_color(struct vm_radix *, vm_pindex_t, int);
80void	*vm_radix_lookup(struct vm_radix *, vm_pindex_t, int);
81int	vm_radix_lookupn(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
82	    void **, int, vm_pindex_t *);
83void	*vm_radix_lookup_le(struct vm_radix *, vm_pindex_t, int);
84void	vm_radix_reclaim_allnodes(struct vm_radix *);
85void	*vm_radix_remove(struct vm_radix *, vm_pindex_t, int);
86void	vm_radix_foreach(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
87	    void (*)(void *));
88
89/*
90 * Look up any entry at a position greater or equal to index.
91 */
92static inline void *
93vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index, int color)
94{
95        void *val;
96
97        if (vm_radix_lookupn(rtree, index, 0, color, &val, 1, &index))
98                return (val);
99        return (NULL);
100}
101
102static inline void *
103vm_radix_last(struct vm_radix *rtree, int color)
104{
105
106	return vm_radix_lookup_le(rtree, 0, color);
107}
108
109static inline void *
110vm_radix_first(struct vm_radix *rtree, int color)
111{
112
113	return vm_radix_lookup_ge(rtree, 0, color);
114}
115
116static inline void *
117vm_radix_next(struct vm_radix *rtree, vm_pindex_t index, int color)
118{
119
120	if (index == -1)
121		return (NULL);
122	return vm_radix_lookup_ge(rtree, index + 1, color);
123}
124
125static inline void *
126vm_radix_prev(struct vm_radix *rtree, vm_pindex_t index, int color)
127{
128
129	if (index == 0)
130		return (NULL);
131	return vm_radix_lookup_le(rtree, index - 1, color);
132}
133
134#endif /* _KERNEL */
135#endif /* !_VM_RADIX_H_ */
136