86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
/*
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* Copyright (c) 1998 Matthew Dillon. Terms of use and redistribution in all
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* forms are covered by the BSD copyright in the file "/usr/src/COPYRIGHT".
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*
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* Implements bitmap resource lists.
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*
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* Usage:
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* blist = blist_create(blocks)
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* (void) blist_destroy(blist)
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* blkno = blist_alloc(blist, count)
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* (void) blist_free(blist, blkno, count)
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* (void) blist_resize(&blist, count, freeextra)
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*
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*
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* Notes:
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* on creation, the entire list is marked reserved. You should
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* first blist_free() the sections you want to make available
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* for allocation before doing general blist_alloc()/free()
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* ops.
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*
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* SWAPBLK_NONE is returned on failure. This module is typically
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* capable of managing up to (2^31) blocks per blist, though
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* the memory utilization would be insane if you actually did
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* that. Managing something like 512MB worth of 4K blocks
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* eats around 32 KBytes of memory.
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_BLIST_H_
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#define _SYS_BLIST_H_
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typedef u_int32_t u_daddr_t; /* unsigned disk address */
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static __inline int
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LOG2(u_daddr_t v)
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{
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int i = -1;
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if (!v)
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return(0);
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while (v) {
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i++;
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v >>= 1;
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}
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return (i);
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}
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/*
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* blmeta and bl_bitmap_t MUST be a power of 2 in size.
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*/
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typedef struct blmeta {
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union {
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daddr_t bmu_avail; /* space available under us */
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u_daddr_t bmu_bitmap; /* bitmap if we are a leaf */
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} u;
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daddr_t bm_bighint; /* biggest contiguous block hint*/
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} blmeta_t;
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typedef struct blist {
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daddr_t bl_blocks; /* area of coverage */
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daddr_t bl_radix; /* coverage radix */
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daddr_t bl_skip; /* starting skip */
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daddr_t bl_free; /* number of free blocks */
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blmeta_t *bl_root; /* root of radix tree */
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daddr_t bl_rootblks; /* daddr_t blks allocated for tree */
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} *blist_t;
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#define BLIST_META_RADIX 16
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#define BLIST_META_RADIX_SHIFT LOG2(BLIST_META_RADIX)
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#define BLIST_BMAP_RADIX (sizeof(u_daddr_t)*8)
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#define BLIST_BMAP_RADIX_SHIFT LOG2(BLIST_BMAP_RADIX)
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#define BLIST_MAX_ALLOC BLIST_BMAP_RADIX
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extern blist_t blist_create(daddr_t blocks);
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extern void blist_destroy(blist_t blist);
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extern daddr_t blist_alloc(blist_t blist, daddr_t count);
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extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
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extern void blist_print(blist_t blist);
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extern void blist_resize(blist_t *pblist, daddr_t count, int freenew);
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#endif /* _SYS_BLIST_H_ */
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