| 0,0 → 1,325 |
|---|
| /* |
| * Copyright (C) 2005 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup genericmm |
| * @{ |
| */ |
| |
| /** |
| * @file |
| * @brief Buddy allocator framework. |
| * |
| * This file contains buddy system allocator framework. |
| * Specialized functions are needed for this abstract framework |
| * to be useful. |
| */ |
| |
| #include <mm/buddy.h> |
| #include <mm/frame.h> |
| #include <arch/types.h> |
| #include <typedefs.h> |
| #include <adt/list.h> |
| #include <debug.h> |
| #include <print.h> |
| |
| /** Return size needed for the buddy configuration data */ |
| size_t buddy_conf_size(int max_order) |
| { |
| return sizeof(buddy_system_t) + (max_order + 1) * sizeof(link_t); |
| } |
| |
| |
| /** Create buddy system |
| * |
| * Allocate memory for and initialize new buddy system. |
| * |
| * @param b Preallocated buddy system control data. |
| * @param max_order The biggest allocable size will be 2^max_order. |
| * @param op Operations for new buddy system. |
| * @param data Pointer to be used by implementation. |
| * |
| * @return New buddy system. |
| */ |
| void buddy_system_create(buddy_system_t *b, |
| uint8_t max_order, |
| buddy_system_operations_t *op, |
| void *data) |
| { |
| int i; |
| |
| ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK); |
| |
| ASSERT(op->find_buddy); |
| ASSERT(op->set_order); |
| ASSERT(op->get_order); |
| ASSERT(op->bisect); |
| ASSERT(op->coalesce); |
| ASSERT(op->mark_busy); |
| |
| /* |
| * Use memory after our own structure |
| */ |
| b->order = (link_t *) (&b[1]); |
| |
| for (i = 0; i <= max_order; i++) |
| list_initialize(&b->order[i]); |
| |
| b->max_order = max_order; |
| b->op = op; |
| b->data = data; |
| } |
| |
| /** Check if buddy system can allocate block |
| * |
| * @param b Buddy system pointer |
| * @param i Size of the block (2^i) |
| * |
| * @return True if block can be allocated |
| */ |
| bool buddy_system_can_alloc(buddy_system_t *b, uint8_t i) { |
| uint8_t k; |
| |
| /* |
| * If requested block is greater then maximal block |
| * we know immediatly that we cannot satisfy the request. |
| */ |
| if (i > b->max_order) return false; |
| |
| /* |
| * Check if any bigger or equal order has free elements |
| */ |
| for (k=i; k <= b->max_order; k++) { |
| if (!list_empty(&b->order[k])) { |
| return true; |
| } |
| } |
| |
| return false; |
| |
| } |
| |
| /** Allocate PARTICULAR block from buddy system |
| * |
| * @ return Block of data or NULL if no such block was found |
| */ |
| link_t *buddy_system_alloc_block(buddy_system_t *b, link_t *block) |
| { |
| link_t *left,*right, *tmp; |
| uint8_t order; |
| |
| left = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK); |
| ASSERT(left); |
| list_remove(left); |
| while (1) { |
| if (! b->op->get_order(b,left)) { |
| b->op->mark_busy(b, left); |
| return left; |
| } |
| |
| order = b->op->get_order(b, left); |
| |
| right = b->op->bisect(b, left); |
| b->op->set_order(b, left, order-1); |
| b->op->set_order(b, right, order-1); |
| |
| tmp = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK); |
| |
| if (tmp == right) { |
| right = left; |
| left = tmp; |
| } |
| ASSERT(tmp == left); |
| b->op->mark_busy(b, left); |
| buddy_system_free(b, right); |
| b->op->mark_available(b, left); |
| } |
| } |
| |
| /** Allocate block from buddy system. |
| * |
| * @param b Buddy system pointer. |
| * @param i Returned block will be 2^i big. |
| * |
| * @return Block of data represented by link_t. |
| */ |
| link_t *buddy_system_alloc(buddy_system_t *b, uint8_t i) |
| { |
| link_t *res, *hlp; |
| |
| ASSERT(i <= b->max_order); |
| |
| /* |
| * If the list of order i is not empty, |
| * the request can be immediatelly satisfied. |
| */ |
| if (!list_empty(&b->order[i])) { |
| res = b->order[i].next; |
| list_remove(res); |
| b->op->mark_busy(b, res); |
| return res; |
| } |
| /* |
| * If order i is already the maximal order, |
| * the request cannot be satisfied. |
| */ |
| if (i == b->max_order) |
| return NULL; |
| |
| /* |
| * Try to recursively satisfy the request from higher order lists. |
| */ |
| hlp = buddy_system_alloc(b, i + 1); |
| |
| /* |
| * The request could not be satisfied |
| * from higher order lists. |
| */ |
| if (!hlp) |
| return NULL; |
| |
| res = hlp; |
| |
| /* |
| * Bisect the block and set order of both of its parts to i. |
| */ |
| hlp = b->op->bisect(b, res); |
| b->op->set_order(b, res, i); |
| b->op->set_order(b, hlp, i); |
| |
| /* |
| * Return the other half to buddy system. Mark the first part |
| * full, so that it won't coalesce again. |
| */ |
| b->op->mark_busy(b, res); |
| buddy_system_free(b, hlp); |
| |
| return res; |
| |
| } |
| |
| /** Return block to buddy system. |
| * |
| * @param b Buddy system pointer. |
| * @param block Block to return. |
| */ |
| void buddy_system_free(buddy_system_t *b, link_t *block) |
| { |
| link_t *buddy, *hlp; |
| uint8_t i; |
| |
| /* |
| * Determine block's order. |
| */ |
| i = b->op->get_order(b, block); |
| |
| ASSERT(i <= b->max_order); |
| |
| if (i != b->max_order) { |
| /* |
| * See if there is any buddy in the list of order i. |
| */ |
| buddy = b->op->find_buddy(b, block); |
| if (buddy) { |
| |
| ASSERT(b->op->get_order(b, buddy) == i); |
| /* |
| * Remove buddy from the list of order i. |
| */ |
| list_remove(buddy); |
| |
| /* |
| * Invalidate order of both block and buddy. |
| */ |
| b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK); |
| b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK); |
| |
| /* |
| * Coalesce block and buddy into one block. |
| */ |
| hlp = b->op->coalesce(b, block, buddy); |
| |
| /* |
| * Set order of the coalesced block to i + 1. |
| */ |
| b->op->set_order(b, hlp, i + 1); |
| |
| /* |
| * Recursively add the coalesced block to the list of order i + 1. |
| */ |
| buddy_system_free(b, hlp); |
| return; |
| } |
| } |
| |
| /* |
| * Insert block into the list of order i. |
| */ |
| list_append(block, &b->order[i]); |
| |
| } |
| |
| /** Prints out structure of buddy system |
| * |
| * @param b Pointer to buddy system |
| * @param elem_size Element size |
| */ |
| void buddy_system_structure_print(buddy_system_t *b, size_t elem_size) { |
| index_t i; |
| count_t cnt, elem_count = 0, block_count = 0; |
| link_t * cur; |
| |
| |
| printf("Order\tBlocks\tSize \tBlock size\tElems per block\n"); |
| printf("-----\t------\t--------\t----------\t---------------\n"); |
| |
| for (i=0;i <= b->max_order; i++) { |
| cnt = 0; |
| if (!list_empty(&b->order[i])) { |
| for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next) |
| cnt++; |
| } |
| |
| 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); |
| if (!list_empty(&b->order[i])) { |
| for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next) { |
| b->op->print_id(b, cur); |
| printf(" "); |
| } |
| } |
| printf("\n"); |
| |
| block_count += cnt; |
| elem_count += (1 << i) * cnt; |
| } |
| printf("-----\t------\t--------\t----------\t---------------\n"); |
| printf("Buddy system contains %zd free elements (%zd blocks)\n" , elem_count, block_count); |
| |
| } |
| |
| /** @} |
| */ |