| 0,0 → 1,232 |
|---|
| /* |
| * 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. |
| */ |
| |
| #include <mm/buddy.h> |
| #include <mm/frame.h> |
| #include <mm/heap.h> |
| #include <arch/types.h> |
| #include <typedefs.h> |
| #include <list.h> |
| #include <debug.h> |
| #include <print.h> |
| |
| /** Create buddy system |
| * |
| * Allocate memory for and initialize new buddy system. |
| * |
| * @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. |
| */ |
| buddy_system_t *buddy_system_create(__u8 max_order, buddy_system_operations_t *op, void *data) |
| { |
| buddy_system_t *b; |
| 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); |
| |
| /* |
| * Allocate memory for structure describing the whole buddy system. |
| */ |
| b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t)); |
| |
| if (b) { |
| /* |
| * Allocate memory for all orders this buddy system will work with. |
| */ |
| b->order = (link_t *) early_malloc(max_order * sizeof(link_t)); |
| if (!b->order) { |
| early_free(b); |
| return NULL; |
| } |
| |
| for (i = 0; i < max_order; i++) |
| list_initialize(&b->order[i]); |
| |
| b->max_order = max_order; |
| b->op = op; |
| b->data = data; |
| } |
| |
| return b; |
| } |
| |
| /** 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, __u8 i) { |
| __u8 k; |
| |
| ASSERT(i < b->max_order); |
| |
| for (k=i; k < b->max_order; k++) { |
| if (!list_empty(&b->order[k])) { |
| return true; |
| } |
| } |
| |
| return false; |
| |
| } |
| |
| /** 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, __u8 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 - 1) |
| 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. |
| * PROBLEM!!!! FILL FIND OTHER PART AS BUDDY AND LINK TOGETHER |
| */ |
| 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; |
| __u8 i; |
| |
| /* |
| * Determine block's order. |
| */ |
| i = b->op->get_order(b, block); |
| |
| ASSERT(i < b->max_order); |
| |
| if (i != b->max_order - 1) { |
| /* |
| * 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]); |
| |
| } |