1 /* 2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * Implements bitmap resource lists. 35 * 36 * Usage: 37 * blist = blist_create(blocks) 38 * (void) blist_destroy(blist) 39 * blkno = blist_alloc(blist, count) 40 * (void) blist_free(blist, blkno, count) 41 * nblks = blist_fill(blist, blkno, count) 42 * (void) blist_resize(&blist, count, freeextra) 43 * 44 * 45 * Notes: 46 * on creation, the entire list is marked reserved. You should 47 * first blist_free() the sections you want to make available 48 * for allocation before doing general blist_alloc()/free() 49 * ops. 50 * 51 * SWAPBLK_NONE is returned on failure. This module is typically 52 * capable of managing up to (2^31) blocks per blist, though 53 * the memory utilization would be insane if you actually did 54 * that. Managing something like 512MB worth of 4K blocks 55 * eats around 32 KBytes of memory. 56 * 57 * $FreeBSD: src/sys/sys/blist.h,v 1.2.2.1 2003/01/12 09:23:12 dillon Exp $ 58 * $DragonFly: src/sys/sys/blist.h,v 1.7 2008/08/10 22:09:51 dillon Exp $ 59 */ 60 61 #ifndef _SYS_BLIST_H_ 62 #define _SYS_BLIST_H_ 63 64 #ifndef _SYS_TYPES_H_ 65 #include <sys/types.h> 66 #endif 67 68 #define SWBLK_BITS 64 69 typedef int64_t swblk_t; 70 typedef u_int64_t u_swblk_t; 71 72 /* 73 * note: currently use SWAPBLK_NONE as an absolute value rather then 74 * a flag bit. 75 */ 76 #define SWAPBLK_MASK ((swblk_t)((u_swblk_t)-1 >> 1)) /* mask */ 77 #define SWAPBLK_NONE ((swblk_t)((u_swblk_t)SWAPBLK_MASK + 1))/* flag */ 78 79 /* 80 * blmeta and bl_bitmap_t MUST be a power of 2 in size. 81 */ 82 83 typedef struct blmeta { 84 union { 85 swblk_t bmu_avail; /* space available under us */ 86 u_swblk_t bmu_bitmap; /* bitmap if we are a leaf */ 87 } u; 88 swblk_t bm_bighint; /* biggest contiguous block hint*/ 89 } blmeta_t; 90 91 typedef struct blist { 92 swblk_t bl_blocks; /* area of coverage */ 93 int64_t bl_radix; /* coverage radix */ 94 swblk_t bl_skip; /* starting skip */ 95 swblk_t bl_free; /* number of free blocks */ 96 blmeta_t *bl_root; /* root of radix tree */ 97 swblk_t bl_rootblks; /* swblk_t blks allocated for tree */ 98 } *blist_t; 99 100 #define BLIST_META_RADIX (sizeof(u_swblk_t)*8/2) /* 2 bits per */ 101 #define BLIST_BMAP_RADIX (sizeof(u_swblk_t)*8) /* 1 bit per */ 102 103 /* 104 * The radix may exceed the size of a 64 bit signed (or unsigned) int 105 * when the maximal number of blocks is allocated. With a 32-bit swblk_t 106 * this corresponds to ~1G x PAGE_SIZE = 4096GB. The swap code usually 107 * divides this by 4, leaving us with a capability of up to four 1TB swap 108 * devices. 109 * 110 * With a 64-bit swblk_t the limitation is some insane number. 111 * 112 * NOTE: For now I don't trust that we overflow-detect properly so we divide 113 * out to ensure that no overflow occurs. 114 */ 115 116 #if SWBLK_BITS == 64 117 #define BLIST_MAXBLKS (0x4000000000000000LL / \ 118 (BLIST_BMAP_RADIX / BLIST_META_RADIX)) 119 #else 120 #define BLIST_MAXBLKS (0x40000000 / \ 121 (BLIST_BMAP_RADIX / BLIST_META_RADIX)) 122 #endif 123 124 #define BLIST_MAX_ALLOC BLIST_BMAP_RADIX 125 126 extern blist_t blist_create(swblk_t blocks); 127 extern void blist_destroy(blist_t blist); 128 extern swblk_t blist_alloc(blist_t blist, swblk_t count); 129 extern swblk_t blist_allocat(blist_t blist, swblk_t count, swblk_t blkat); 130 extern void blist_free(blist_t blist, swblk_t blkno, swblk_t count); 131 extern swblk_t blist_fill(blist_t blist, swblk_t blkno, swblk_t count); 132 extern void blist_print(blist_t blist); 133 extern void blist_resize(blist_t *pblist, swblk_t count, int freenew); 134 135 #endif /* _SYS_BLIST_H_ */ 136