1/*
2 * Copyright (c) 1998 Matthew Dillon.  Terms of use and redistribution in all
3 * forms are covered by the BSD copyright in the file "/usr/src/COPYRIGHT".
4 *
5 * Implements bitmap resource lists.
6 *
7 *	Usage:
8 *		blist = blist_create(blocks)
9 *		(void)  blist_destroy(blist)
10 *		blkno = blist_alloc(blist, count)
11 *		(void)  blist_free(blist, blkno, count)
12 *		(void)  blist_resize(&blist, count, freeextra)
13 *
14 *
15 *	Notes:
16 *		on creation, the entire list is marked reserved.  You should
17 *		first blist_free() the sections you want to make available
18 *		for allocation before doing general blist_alloc()/free()
19 *		ops.
20 *
21 *		SWAPBLK_NONE is returned on failure.  This module is typically
22 *		capable of managing up to (2^31) blocks per blist, though
23 *		the memory utilization would be insane if you actually did
24 *		that.  Managing something like 512MB worth of 4K blocks
25 *		eats around 32 KBytes of memory.
26 *
27 * $FreeBSD: src/sys/sys/blist.h,v 1.2 1999/08/28 00:51:33 peter Exp $
28 */
29
30#ifndef _SYS_BLIST_H_
31#define _SYS_BLIST_H_
32
33#define LOG2(v)		(((u_daddr_t)(v) >= 0x80000000U) ? 31 : \
34			((u_daddr_t)(v) >= 0x40000000U) ? 30 : \
35			((u_daddr_t)(v) >= 0x20000000U) ? 29 : \
36			((u_daddr_t)(v) >= 0x10000000U) ? 28 : \
37			((u_daddr_t)(v) >= 0x08000000U) ? 27 : \
38			((u_daddr_t)(v) >= 0x04000000U) ? 26 : \
39			((u_daddr_t)(v) >= 0x02000000U) ? 25 : \
40			((u_daddr_t)(v) >= 0x01000000U) ? 24 : \
41			((u_daddr_t)(v) >= 0x00800000U) ? 23 : \
42			((u_daddr_t)(v) >= 0x00400000U) ? 22 : \
43			((u_daddr_t)(v) >= 0x00200000U) ? 21 : \
44			((u_daddr_t)(v) >= 0x00100000U) ? 20 : \
45			((u_daddr_t)(v) >= 0x00080000U) ? 19 : \
46			((u_daddr_t)(v) >= 0x00040000U) ? 18 : \
47			((u_daddr_t)(v) >= 0x00020000U) ? 17 : \
48			((u_daddr_t)(v) >= 0x00010000U) ? 16 : \
49			((u_daddr_t)(v) >= 0x00008000U) ? 15 : \
50			((u_daddr_t)(v) >= 0x00004000U) ? 14 : \
51			((u_daddr_t)(v) >= 0x00002000U) ? 13 : \
52			((u_daddr_t)(v) >= 0x00001000U) ? 12 : \
53			((u_daddr_t)(v) >= 0x00000800U) ? 11 : \
54			((u_daddr_t)(v) >= 0x00000400U) ? 10 : \
55			((u_daddr_t)(v) >= 0x00000200U) ? 9 : \
56			((u_daddr_t)(v) >= 0x00000100U) ? 8 : \
57			((u_daddr_t)(v) >= 0x00000080U) ? 7 : \
58			((u_daddr_t)(v) >= 0x00000040U) ? 6 : \
59			((u_daddr_t)(v) >= 0x00000020U) ? 5 : \
60			((u_daddr_t)(v) >= 0x00000010U) ? 4 : \
61			((u_daddr_t)(v) >= 0x00000008U) ? 3 : \
62			((u_daddr_t)(v) >= 0x00000004U) ? 2 : \
63			((u_daddr_t)(v) >= 0x00000002U) ? 1 : 0)
64
65/*
66 * blmeta and bl_bitmap_t MUST be a power of 2 in size.
67 */
68
69typedef struct blmeta {
70	union {
71	    daddr_t	bmu_avail;	/* space available under us	*/
72	    u_daddr_t	bmu_bitmap;	/* bitmap if we are a leaf	*/
73	} u;
74	daddr_t		bm_bighint;	/* biggest contiguous block hint*/
75} blmeta_t;
76
77typedef struct blist {
78	daddr_t		bl_blocks;	/* area of coverage		*/
79	daddr_t		bl_radix;	/* coverage radix		*/
80	daddr_t		bl_skip;	/* starting skip		*/
81	daddr_t		bl_free;	/* number of free blocks	*/
82	blmeta_t	*bl_root;	/* root of radix tree		*/
83	daddr_t		bl_rootblks;	/* daddr_t blks allocated for tree */
84} *blist_t;
85
86#define BLIST_META_RADIX	16
87#define BLIST_META_RADIX_SHIFT	LOG2(BLIST_META_RADIX)
88#define BLIST_BMAP_RADIX	(sizeof(u_daddr_t)*8)
89#define BLIST_BMAP_RADIX_SHIFT	LOG2(BLIST_BMAP_RADIX)
90
91#define BLIST_MAX_ALLOC		BLIST_BMAP_RADIX
92
93extern blist_t blist_create(daddr_t blocks);
94extern void blist_destroy(blist_t blist);
95extern daddr_t blist_alloc(blist_t blist, daddr_t count);
96extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
97extern void blist_print(blist_t blist);
98extern void blist_resize(blist_t *pblist, daddr_t count, int freenew);
99
100#endif	/* _SYS_BLIST_H_ */
101