vm_radix.h revision 226980 
1/*
2 * Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 */
27
28#ifndef _VM_RADIX_H_
29#define _VM_RADIX_H_
30
31#include <sys/queue.h>
32
33/* Default values of the tree parameters */
34#define	VM_RADIX_WIDTH	5
35#define	VM_RADIX_COUNT	(1 << VM_RADIX_WIDTH)
36#define	VM_RADIX_MASK	(VM_RADIX_COUNT - 1)
37#define	VM_RADIX_LIMIT	howmany((sizeof(vm_pindex_t) * NBBY), VM_RADIX_WIDTH)
38#define	VM_RADIX_FLAGS	0x3	/* Flag bits stored in node pointers. */
39#define	VM_RADIX_BLACK	0x1	/* Black node. (leaf only) */
40#define	VM_RADIX_RED	0x2	/* Red node. (leaf only) */
41#define	VM_RADIX_ANY	(VM_RADIX_RED | VM_RADIX_BLACK)
42#define	VM_RADIX_EMPTY	0x1	/* Empty hint. (internal only) */
43#define	VM_RADIX_HEIGHT	0xf	/* Bits of height in root */
44#define	VM_RADIX_STACK	8	/* Nodes to store on stack. */
45
46CTASSERT(VM_RADIX_HEIGHT >= VM_RADIX_LIMIT);
47
48/* Calculates maximum value for a tree of height h. */
49#define	VM_RADIX_MAX(h)							\
50	    ((h) == VM_RADIX_LIMIT ? ((vm_pindex_t)-1) :		\
51	    (((vm_pindex_t)1 << ((h) * VM_RADIX_WIDTH)) - 1))
52
53struct vm_radix_node {
54	void		*rn_child[VM_RADIX_COUNT];	/* child nodes. */
55    	uint16_t	rn_count;			/* Valid children. */
56};
57
58/*
59 * Radix tree root.  The height and pointer are set together to permit
60 * coherent lookups while the root is modified.
61 */
62struct vm_radix {
63	uintptr_t	rt_root;		/* root + height */
64};
65
66void	vm_radix_init(void);
67
68/*
69 * Functions which only work with black nodes. (object lock)
70 */
71int 	vm_radix_insert(struct vm_radix *, vm_pindex_t, void *);
72void 	vm_radix_shrink(struct vm_radix *);
73
74/*
75 * Functions which work on specified colors. (object, vm_page_queue_free locks)
76 */
77void	*vm_radix_color(struct vm_radix *, vm_pindex_t, int);
78void	*vm_radix_lookup(struct vm_radix *, vm_pindex_t, int);
79int	vm_radix_lookupn(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
80	    void **, int, vm_pindex_t *);
81void	*vm_radix_lookup_le(struct vm_radix *, vm_pindex_t, int);
82void	vm_radix_reclaim_allnodes(struct vm_radix *);
83void	*vm_radix_remove(struct vm_radix *, vm_pindex_t, int);
84void	vm_radix_foreach(struct vm_radix *, vm_pindex_t, vm_pindex_t, int,
85	    void (*)(void *));
86
87/*
88 * Look up any entry at a position greater or equal to index.
89 */
90static inline void *
91vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index, int color)
92{
93        void *val;
94
95        if (vm_radix_lookupn(rtree, index, 0, color, &val, 1, &index))
96                return (val);
97        return (NULL);
98}
99
100#endif /* !_VM_RADIX_H_ */
101