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377 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2005 Jakub Jermar
377 jermar 3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1757 jermar 29
/** @addtogroup genericmm
1702 cejka 30
 * @{
31
 */
32
 
1248 jermar 33
/**
1702 cejka 34
 * @file
1248 jermar 35
 * @brief   Buddy allocator framework.
36
 *
37
 * This file contains buddy system allocator framework.
38
 * Specialized functions are needed for this abstract framework
39
 * to be useful.
40
 */
41
 
377 jermar 42
#include <mm/buddy.h>
43
#include <mm/frame.h>
44
#include <arch/types.h>
45
#include <debug.h>
533 bondari 46
#include <print.h>
377 jermar 47
 
814 palkovsky 48
/** Return size needed for the buddy configuration data */
49
size_t buddy_conf_size(int max_order)
50
{
51
    return sizeof(buddy_system_t) + (max_order + 1) * sizeof(link_t);
52
}
53
 
54
 
377 jermar 55
/** Create buddy system
56
 *
57
 * Allocate memory for and initialize new buddy system.
58
 *
1229 jermar 59
 * @param b Preallocated buddy system control data.
377 jermar 60
 * @param max_order The biggest allocable size will be 2^max_order.
61
 * @param op Operations for new buddy system.
490 jermar 62
 * @param data Pointer to be used by implementation.
377 jermar 63
 *
64
 * @return New buddy system.
65
 */
814 palkovsky 66
void buddy_system_create(buddy_system_t *b,
1780 jermar 67
             uint8_t max_order,
814 palkovsky 68
             buddy_system_operations_t *op,
69
             void *data)
377 jermar 70
{
71
    int i;
72
 
378 jermar 73
    ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);
74
 
377 jermar 75
    ASSERT(op->find_buddy);
76
    ASSERT(op->set_order);
77
    ASSERT(op->get_order);
78
    ASSERT(op->bisect);
79
    ASSERT(op->coalesce);
533 bondari 80
    ASSERT(op->mark_busy);
377 jermar 81
 
82
    /*
814 palkovsky 83
     * Use memory after our own structure
84
     */
85
    b->order = (link_t *) (&b[1]);
377 jermar 86
 
814 palkovsky 87
    for (i = 0; i <= max_order; i++)
88
        list_initialize(&b->order[i]);
89
 
90
    b->max_order = max_order;
91
    b->op = op;
92
    b->data = data;
377 jermar 93
}
94
 
533 bondari 95
/** Check if buddy system can allocate block
96
 *
97
 * @param b Buddy system pointer
98
 * @param i Size of the block (2^i)
99
 *
100
 * @return True if block can be allocated
101
 */
1780 jermar 102
bool buddy_system_can_alloc(buddy_system_t *b, uint8_t i) {
103
    uint8_t k;
533 bondari 104
 
735 bondari 105
    /*
106
     * If requested block is greater then maximal block
107
     * we know immediatly that we cannot satisfy the request.
108
     */
109
    if (i > b->max_order) return false;
110
 
111
    /*
112
     * Check if any bigger or equal order has free elements
113
     */
114
    for (k=i; k <= b->max_order; k++) {
533 bondari 115
        if (!list_empty(&b->order[k])) {
116
            return true;
117
        }
118
    }
119
 
120
    return false;
121
 
122
}
123
 
814 palkovsky 124
/** Allocate PARTICULAR block from buddy system
125
 *
126
 * @ return Block of data or NULL if no such block was found
127
 */
128
link_t *buddy_system_alloc_block(buddy_system_t *b, link_t *block)
129
{
130
    link_t *left,*right, *tmp;
1780 jermar 131
    uint8_t order;
814 palkovsky 132
 
133
    left = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK);
134
    ASSERT(left);
135
    list_remove(left);
136
    while (1) {
137
        if (! b->op->get_order(b,left)) {
138
            b->op->mark_busy(b, left);
139
            return left;
140
        }
141
 
142
        order = b->op->get_order(b, left);
143
 
144
        right = b->op->bisect(b, left);
145
        b->op->set_order(b, left, order-1);
146
        b->op->set_order(b, right, order-1);
147
 
148
        tmp = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK);
149
 
150
        if (tmp == right) {
151
            right = left;
152
            left = tmp;
822 palkovsky 153
        }
154
        ASSERT(tmp == left);
814 palkovsky 155
        b->op->mark_busy(b, left);
156
        buddy_system_free(b, right);
157
        b->op->mark_available(b, left);
158
    }
159
}
160
 
377 jermar 161
/** Allocate block from buddy system.
162
 *
163
 * @param b Buddy system pointer.
164
 * @param i Returned block will be 2^i big.
165
 *
166
 * @return Block of data represented by link_t.
167
 */
1780 jermar 168
link_t *buddy_system_alloc(buddy_system_t *b, uint8_t i)
377 jermar 169
{
170
    link_t *res, *hlp;
171
 
735 bondari 172
    ASSERT(i <= b->max_order);
377 jermar 173
 
174
    /*
175
     * If the list of order i is not empty,
176
     * the request can be immediatelly satisfied.
177
     */
178
    if (!list_empty(&b->order[i])) {
179
        res = b->order[i].next;
180
        list_remove(res);
533 bondari 181
        b->op->mark_busy(b, res);
377 jermar 182
        return res;
183
    }
184
    /*
185
     * If order i is already the maximal order,
186
     * the request cannot be satisfied.
187
     */
735 bondari 188
    if (i == b->max_order)
377 jermar 189
        return NULL;
190
 
191
    /*
192
     * Try to recursively satisfy the request from higher order lists.
193
     */
194
    hlp = buddy_system_alloc(b, i + 1);
195
 
196
    /*
197
     * The request could not be satisfied
198
     * from higher order lists.
199
     */
200
    if (!hlp)
201
        return NULL;
202
 
203
    res = hlp;
204
 
205
    /*
206
     * Bisect the block and set order of both of its parts to i.
207
     */
489 jermar 208
    hlp = b->op->bisect(b, res);
209
    b->op->set_order(b, res, i);
210
    b->op->set_order(b, hlp, i);
377 jermar 211
 
212
    /*
814 palkovsky 213
     * Return the other half to buddy system. Mark the first part
815 jermar 214
     * full, so that it won't coalesce again.
377 jermar 215
     */
533 bondari 216
    b->op->mark_busy(b, res);
377 jermar 217
    buddy_system_free(b, hlp);
218
 
219
    return res;
220
 
221
}
222
 
223
/** Return block to buddy system.
224
 *
225
 * @param b Buddy system pointer.
226
 * @param block Block to return.
227
 */
228
void buddy_system_free(buddy_system_t *b, link_t *block)
229
{
230
    link_t *buddy, *hlp;
1780 jermar 231
    uint8_t i;
533 bondari 232
 
377 jermar 233
    /*
234
     * Determine block's order.
235
     */
489 jermar 236
    i = b->op->get_order(b, block);
377 jermar 237
 
735 bondari 238
    ASSERT(i <= b->max_order);
377 jermar 239
 
735 bondari 240
    if (i != b->max_order) {
377 jermar 241
        /*
379 jermar 242
         * See if there is any buddy in the list of order i.
377 jermar 243
         */
489 jermar 244
        buddy = b->op->find_buddy(b, block);
379 jermar 245
        if (buddy) {
246
 
489 jermar 247
            ASSERT(b->op->get_order(b, buddy) == i);
379 jermar 248
            /*
249
             * Remove buddy from the list of order i.
250
             */
251
            list_remove(buddy);
378 jermar 252
 
379 jermar 253
            /*
254
             * Invalidate order of both block and buddy.
255
             */
489 jermar 256
            b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);
257
            b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);
379 jermar 258
 
259
            /*
260
             * Coalesce block and buddy into one block.
261
             */
489 jermar 262
            hlp = b->op->coalesce(b, block, buddy);
377 jermar 263
 
379 jermar 264
            /*
265
             * Set order of the coalesced block to i + 1.
266
             */
489 jermar 267
            b->op->set_order(b, hlp, i + 1);
377 jermar 268
 
379 jermar 269
            /*
270
             * Recursively add the coalesced block to the list of order i + 1.
271
             */
272
            buddy_system_free(b, hlp);
273
            return;
274
        }
377 jermar 275
    }
276
 
379 jermar 277
    /*
278
     * Insert block into the list of order i.
279
     */
280
    list_append(block, &b->order[i]);
281
 
377 jermar 282
}
683 bondari 283
 
284
/** Prints out structure of buddy system
285
 *
286
 * @param b Pointer to buddy system
1708 jermar 287
 * @param elem_size Element size
683 bondari 288
 */
686 bondari 289
void buddy_system_structure_print(buddy_system_t *b, size_t elem_size) {
683 bondari 290
    index_t i;
291
    count_t cnt, elem_count = 0, block_count = 0;
292
    link_t * cur;
293
 
294
 
686 bondari 295
    printf("Order\tBlocks\tSize    \tBlock size\tElems per block\n");
296
    printf("-----\t------\t--------\t----------\t---------------\n");
683 bondari 297
 
735 bondari 298
    for (i=0;i <= b->max_order; i++) {
683 bondari 299
        cnt = 0;
300
        if (!list_empty(&b->order[i])) {
701 jermar 301
            for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next)
302
                cnt++;
683 bondari 303
        }
304
 
1224 cejka 305
        printf("#%zd\t%5zd\t%7zdK\t%8zdK\t%6zd\t", i, cnt, (cnt * (1 << i) * elem_size) >> 10, ((1 << i) * elem_size) >> 10, 1 << i);
822 palkovsky 306
        if (!list_empty(&b->order[i])) {
307
            for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next) {
308
                b->op->print_id(b, cur);
309
                printf(" ");
310
            }
311
        }
312
        printf("\n");
313
 
683 bondari 314
        block_count += cnt;
315
        elem_count += (1 << i) * cnt;
316
    }
686 bondari 317
    printf("-----\t------\t--------\t----------\t---------------\n");
1196 cejka 318
    printf("Buddy system contains %zd free elements (%zd blocks)\n" , elem_count, block_count);
683 bondari 319
 
320
}
1702 cejka 321
 
1757 jermar 322
/** @}
1702 cejka 323
 */