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Commit	Line	Data
	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
	69	typedef 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
	77	typedef 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
	93	#if defined(__APPLE__)
	94	#define SWAPBLK_NONE ((daddr_t)-1)
	95	#endif /* __APPLE__ */
	96
	97	extern blist_t blist_create(daddr_t blocks);
	98	extern void blist_destroy(blist_t blist);
	99	extern daddr_t blist_alloc(blist_t blist, daddr_t count);
	100	extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
	101	extern void blist_print(blist_t blist);
	102	extern void blist_resize(blist_t *pblist, daddr_t count, int freenew);
	103
	104	#endif /* _SYS_BLIST_H_ */