FreeBSD/Linux Kernel Cross Reference
sys/sys/blist.h
1 /*-
2 * Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
3 * Redistribution and use in source and binary forms, with or without
4 * modification, are permitted provided that the following conditions
5 * are met:
6 * 1. Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 * 2. Redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution.
11 * 4. Neither the name of the University nor the names of its contributors
12 * may be used to endorse or promote products derived from this software
13 * without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
21 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 /*
29 * Implements bitmap resource lists.
30 *
31 * Usage:
32 * blist = blist_create(blocks, flags)
33 * (void) blist_destroy(blist)
34 * blkno = blist_alloc(blist, count)
35 * (void) blist_free(blist, blkno, count)
36 * nblks = blist_fill(blist, blkno, count)
37 * (void) blist_resize(&blist, count, freeextra, flags)
38 *
39 *
40 * Notes:
41 * on creation, the entire list is marked reserved. You should
42 * first blist_free() the sections you want to make available
43 * for allocation before doing general blist_alloc()/free()
44 * ops.
45 *
46 * SWAPBLK_NONE is returned on failure. This module is typically
47 * capable of managing up to (2^31) blocks per blist, though
48 * the memory utilization would be insane if you actually did
49 * that. Managing something like 512MB worth of 4K blocks
50 * eats around 32 KBytes of memory.
51 *
52 * $FreeBSD: src/sys/sys/blist.h,v 1.10 2008/05/05 19:48:54 kmacy Exp $
53
54 */
55
56 #ifndef _SYS_BLIST_H_
57 #define _SYS_BLIST_H_
58
59 typedef u_int32_t u_daddr_t; /* unsigned disk address */
60
61 /*
62 * note: currently use SWAPBLK_NONE as an absolute value rather then
63 * a flag bit.
64 */
65
66 #define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */
67 #define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */
68
69 /*
70 * blmeta and bl_bitmap_t MUST be a power of 2 in size.
71 */
72
73 typedef struct blmeta {
74 union {
75 daddr_t bmu_avail; /* space available under us */
76 u_daddr_t bmu_bitmap; /* bitmap if we are a leaf */
77 } u;
78 daddr_t bm_bighint; /* biggest contiguous block hint*/
79 } blmeta_t;
80
81 typedef struct blist {
82 daddr_t bl_blocks; /* area of coverage */
83 daddr_t bl_radix; /* coverage radix */
84 daddr_t bl_skip; /* starting skip */
85 daddr_t bl_free; /* number of free blocks */
86 blmeta_t *bl_root; /* root of radix tree */
87 daddr_t bl_rootblks; /* daddr_t blks allocated for tree */
88 } *blist_t;
89
90 #define BLIST_META_RADIX 16
91 #define BLIST_BMAP_RADIX (sizeof(u_daddr_t)*8)
92
93 #define BLIST_MAX_ALLOC BLIST_BMAP_RADIX
94
95 extern blist_t blist_create(daddr_t blocks, int flags);
96 extern void blist_destroy(blist_t blist);
97 extern daddr_t blist_alloc(blist_t blist, daddr_t count);
98 extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
99 extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
100 extern void blist_print(blist_t blist);
101 extern void blist_resize(blist_t *pblist, daddr_t count, int freenew, int flags);
102
103 #endif /* _SYS_BLIST_H_ */
104
105
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