1 /* $OpenBSD: blist.h,v 1.2 2022/08/06 13:44:04 semarie Exp $ */ 2 /* DragonFlyBSD:7b80531f545c7d3c51c1660130c71d01f6bccbe0:/sys/sys/blist.h */ 3 /* 4 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved. 5 * 6 * This code is derived from software contributed to The DragonFly Project 7 * by Matthew Dillon <dillon@backplane.com> 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 3. Neither the name of The DragonFly Project nor the names of its 20 * contributors may be used to endorse or promote products derived 21 * from this software without specific, prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 26 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 27 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 29 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 31 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * Implements bitmap resource lists. 37 * 38 * Usage: 39 * blist = blist_create(blocks) 40 * (void) blist_destroy(blist) 41 * blkno = blist_alloc(blist, count) 42 * (void) blist_free(blist, blkno, count) 43 * nblks = blist_fill(blist, blkno, count) 44 * (void) blist_resize(&blist, count, freeextra) 45 * 46 * 47 * Notes: 48 * on creation, the entire list is marked reserved. You should 49 * first blist_free() the sections you want to make available 50 * for allocation before doing general blist_alloc()/free() 51 * ops. 52 * 53 * SWAPBLK_NONE is returned on failure. This module is typically 54 * capable of managing up to (2^31) blocks per blist, though 55 * the memory utilization would be insane if you actually did 56 * that. Managing something like 512MB worth of 4K blocks 57 * eats around 32 KBytes of memory. 58 * 59 * $FreeBSD: src/sys/sys/blist.h,v 1.2.2.1 2003/01/12 09:23:12 dillon Exp $ 60 */ 61 62 #ifndef _SYS_BLIST_H_ 63 #define _SYS_BLIST_H_ 64 65 #ifndef _SYS_TYPES_H_ 66 #include <sys/types.h> 67 #endif 68 69 typedef u_long 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_NONE ((swblk_t)-1) 77 78 /* 79 * blmeta and bl_bitmap_t MUST be a power of 2 in size. 80 */ 81 82 typedef struct blmeta { 83 union { 84 swblk_t bmu_avail; /* space available under us */ 85 u_swblk_t bmu_bitmap; /* bitmap if we are a leaf */ 86 } u; 87 swblk_t bm_bighint; /* biggest contiguous block hint*/ 88 } blmeta_t; 89 90 typedef struct blist { 91 swblk_t bl_blocks; /* area of coverage */ 92 /* XXX int64_t bl_radix */ 93 swblk_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 defined(_LP64) 117 /* swblk_t 64bits */ 118 #define BLIST_MAXBLKS (0x4000000000000000LL / \ 119 (BLIST_BMAP_RADIX / BLIST_META_RADIX)) 120 #else 121 #define BLIST_MAXBLKS (0x40000000 / \ 122 (BLIST_BMAP_RADIX / BLIST_META_RADIX)) 123 #endif 124 125 #define BLIST_MAX_ALLOC BLIST_BMAP_RADIX 126 127 blist_t blist_create(swblk_t); 128 void blist_destroy(blist_t); 129 swblk_t blist_alloc(blist_t, swblk_t); 130 swblk_t blist_allocat(blist_t, swblk_t, swblk_t); 131 void blist_free(blist_t, swblk_t, swblk_t); 132 swblk_t blist_fill(blist_t, swblk_t, swblk_t); 133 void blist_print(blist_t); 134 void blist_resize(blist_t *, swblk_t, int); 135 void blist_gapfind(blist_t, swblk_t *, swblk_t *); 136 137 #endif /* _SYS_BLIST_H_ */ 138