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| Rev | Author | Line No. | Line |
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| 377 | jermar | 1 | /* |
| 2 | * Copyright (C) 2005 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | #include <mm/buddy.h> |
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| 30 | #include <mm/frame.h> |
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| 31 | #include <mm/heap.h> |
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| 32 | #include <arch/types.h> |
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| 33 | #include <typedefs.h> |
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| 34 | #include <list.h> |
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| 35 | #include <debug.h> |
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| 36 | |||
| 37 | /** Create buddy system |
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| 38 | * |
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| 39 | * Allocate memory for and initialize new buddy system. |
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| 40 | * |
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| 41 | * @param max_order The biggest allocable size will be 2^max_order. |
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| 42 | * @param op Operations for new buddy system. |
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| 43 | * |
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| 44 | * @return New buddy system. |
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| 45 | */ |
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| 46 | buddy_system_t *buddy_system_create(__u8 max_order, buddy_operations_t *op) |
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| 47 | { |
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| 48 | buddy_system_t *b; |
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| 49 | int i; |
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| 50 | |||
| 378 | jermar | 51 | ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK); |
| 52 | |||
| 377 | jermar | 53 | ASSERT(op->find_buddy); |
| 54 | ASSERT(op->set_order); |
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| 55 | ASSERT(op->get_order); |
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| 56 | ASSERT(op->bisect); |
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| 57 | ASSERT(op->coalesce); |
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| 58 | |||
| 59 | /* |
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| 60 | * Allocate memory for structure describing the whole buddy system. |
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| 61 | */ |
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| 62 | b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t)); |
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| 63 | |||
| 64 | if (b) { |
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| 65 | /* |
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| 66 | * Allocate memory for all orders this buddy system will work with. |
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| 67 | */ |
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| 68 | b->order = (link_t *) early_malloc(max_order * sizeof(link_t)); |
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| 69 | if (!b->order) { |
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| 70 | early_free(b); |
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| 71 | return NULL; |
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| 72 | } |
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| 73 | |||
| 74 | for (i = 0; i < max_order; i++) |
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| 75 | list_initialize(&b->order[i]); |
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| 76 | |||
| 77 | b->max_order = max_order; |
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| 78 | b->op = op; |
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| 79 | } |
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| 80 | |||
| 81 | return b; |
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| 82 | } |
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| 83 | |||
| 84 | /** Allocate block from buddy system. |
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| 85 | * |
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| 86 | * Allocate block from buddy system. |
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| 87 | * |
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| 88 | * @param b Buddy system pointer. |
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| 89 | * @param i Returned block will be 2^i big. |
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| 90 | * |
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| 91 | * @return Block of data represented by link_t. |
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| 92 | */ |
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| 93 | link_t *buddy_system_alloc(buddy_system_t *b, __u8 i) |
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| 94 | { |
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| 95 | link_t *res, *hlp; |
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| 96 | |||
| 97 | ASSERT(i < b->max_order); |
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| 98 | |||
| 99 | /* |
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| 100 | * If the list of order i is not empty, |
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| 101 | * the request can be immediatelly satisfied. |
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| 102 | */ |
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| 103 | if (!list_empty(&b->order[i])) { |
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| 104 | res = b->order[i].next; |
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| 105 | list_remove(res); |
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| 106 | return res; |
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| 107 | } |
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| 108 | |||
| 109 | /* |
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| 110 | * If order i is already the maximal order, |
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| 111 | * the request cannot be satisfied. |
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| 112 | */ |
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| 113 | if (i == b->max_order - 1) |
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| 114 | return NULL; |
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| 115 | |||
| 116 | /* |
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| 117 | * Try to recursively satisfy the request from higher order lists. |
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| 118 | */ |
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| 119 | hlp = buddy_system_alloc(b, i + 1); |
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| 120 | |||
| 121 | /* |
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| 122 | * The request could not be satisfied |
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| 123 | * from higher order lists. |
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| 124 | */ |
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| 125 | if (!hlp) |
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| 126 | return NULL; |
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| 127 | |||
| 128 | res = hlp; |
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| 129 | |||
| 130 | /* |
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| 131 | * Bisect the block and set order of both of its parts to i. |
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| 132 | */ |
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| 133 | hlp = b->op->bisect(res); |
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| 134 | b->op->set_order(res, i); |
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| 135 | b->op->set_order(hlp, i); |
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| 136 | |||
| 137 | /* |
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| 138 | * Return the other half to buddy system. |
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| 139 | */ |
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| 140 | buddy_system_free(b, hlp); |
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| 141 | |||
| 142 | return res; |
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| 143 | |||
| 144 | } |
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| 145 | |||
| 146 | /** Return block to buddy system. |
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| 147 | * |
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| 148 | * Return block to buddy system. |
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| 149 | * |
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| 150 | * @param b Buddy system pointer. |
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| 151 | * @param block Block to return. |
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| 152 | */ |
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| 153 | void buddy_system_free(buddy_system_t *b, link_t *block) |
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| 154 | { |
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| 155 | link_t *buddy, *hlp; |
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| 156 | __u8 i; |
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| 157 | |||
| 158 | /* |
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| 159 | * Determine block's order. |
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| 160 | */ |
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| 161 | i = b->op->get_order(block); |
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| 162 | |||
| 163 | ASSERT(i < b->max_order); |
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| 164 | |||
| 165 | /* |
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| 166 | * See if there is any buddy in the list of order i. |
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| 167 | */ |
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| 168 | buddy = b->op->find_buddy(block); |
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| 169 | |||
| 170 | if (buddy && i != b->max_order - 1) { |
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| 378 | jermar | 171 | |
| 172 | ASSERT(b->op->get_order(buddy) == i); |
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| 173 | |||
| 377 | jermar | 174 | /* |
| 175 | * Remove buddy from the list of order i. |
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| 176 | */ |
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| 177 | list_remove(buddy); |
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| 178 | |||
| 179 | /* |
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| 378 | jermar | 180 | * Invalidate order of both block and buddy. |
| 181 | */ |
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| 182 | b->op->set_order(block, BUDDY_SYSTEM_INNER_BLOCK); |
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| 183 | b->op->set_order(buddy, BUDDY_SYSTEM_INNER_BLOCK); |
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| 184 | |||
| 185 | /* |
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| 377 | jermar | 186 | * Coalesce block and buddy into one block. |
| 187 | */ |
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| 188 | hlp = b->op->coalesce(block, buddy); |
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| 189 | |||
| 190 | /* |
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| 191 | * Set order of the coalesced block to i + 1. |
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| 192 | */ |
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| 193 | b->op->set_order(hlp, i + 1); |
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| 194 | |||
| 195 | /* |
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| 196 | * Recursively add the coalesced block to the list of order i + 1. |
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| 197 | */ |
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| 198 | buddy_system_free(b, hlp); |
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| 199 | } |
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| 200 | else { |
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| 201 | /* |
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| 202 | * Insert block into the list of order i. |
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| 203 | */ |
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| 204 | list_append(block, &b->order[i]); |
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| 205 | } |
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| 206 | |||
| 207 | } |