vm_radix.h revision 226876
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_HEIGHT 0xf /* Bits of height in root */ 39 40CTASSERT(VM_RADIX_HEIGHT >= VM_RADIX_LIMIT); 41 42/* Calculates maximum value for a tree of height h. */ 43#define VM_RADIX_MAX(h) \ 44 ((h) == VM_RADIX_LIMIT ? ((vm_pindex_t)-1) : \ 45 (((vm_pindex_t)1 << ((h) * VM_RADIX_WIDTH)) - 1)) 46 47struct vm_radix_node { 48 void *rn_child[VM_RADIX_COUNT]; /* child nodes. */ 49 uint16_t rn_count; /* Valid children. */ 50}; 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 60void vm_radix_init(void); 61int vm_radix_insert(struct vm_radix *, vm_pindex_t, void *); 62void *vm_radix_remove(struct vm_radix *, vm_pindex_t); 63void *vm_radix_lookup(struct vm_radix *, vm_pindex_t); 64int vm_radix_lookupn(struct vm_radix *rtree, vm_pindex_t start, 65 vm_pindex_t end, void **out, int cnt, vm_pindex_t *next); 66void *vm_radix_lookup_le(struct vm_radix *, vm_pindex_t); 67void vm_radix_shrink(struct vm_radix *); 68 69/* 70 * Look up any entry at a position greater or equal to index. 71 */ 72static inline void * 73vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index) 74{ 75 vm_pindex_t unused; 76 void *val; 77 78 if (vm_radix_lookupn(rtree, index, 0, &val, 1, &unused)) 79 return (val); 80 return (NULL); 81} 82 83#endif /* !_VM_RADIX_H_ */ 84