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| 2 | pj | 1 | /* |
| 2 | * Project: S.Ha.R.K. |
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| 3 | * |
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| 4 | * Coordinators: |
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| 5 | * Giorgio Buttazzo <giorgio@sssup.it> |
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| 6 | * Paolo Gai <pj@gandalf.sssup.it> |
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| 7 | * |
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| 8 | * Authors : |
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| 9 | * Paolo Gai <pj@gandalf.sssup.it> |
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| 10 | * (see the web pages for full authors list) |
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| 11 | * |
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| 12 | * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy) |
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| 13 | * |
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| 14 | * http://www.sssup.it |
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| 15 | * http://retis.sssup.it |
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| 16 | * http://shark.sssup.it |
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| 17 | */ |
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| 18 | |||
| 19 | /** |
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| 20 | ------------ |
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| 21 | CVS : $Id: free.c,v 1.1.1.1 2002-03-29 14:12:52 pj Exp $ |
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| 22 | |||
| 23 | File: $File$ |
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| 24 | Revision: $Revision: 1.1.1.1 $ |
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| 25 | Last update: $Date: 2002-03-29 14:12:52 $ |
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| 26 | ------------ |
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| 27 | |||
| 28 | this code is from: |
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| 29 | List-based Memory Management, from OsKit. |
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| 30 | |||
| 31 | **/ |
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| 32 | |||
| 33 | /* |
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| 34 | * Copyright (C) 2000 Paolo Gai |
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| 35 | * |
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| 36 | * This program is free software; you can redistribute it and/or modify |
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| 37 | * it under the terms of the GNU General Public License as published by |
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| 38 | * the Free Software Foundation; either version 2 of the License, or |
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| 39 | * (at your option) any later version. |
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| 40 | * |
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| 41 | * This program is distributed in the hope that it will be useful, |
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| 42 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 43 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 44 | * GNU General Public License for more details. |
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| 45 | * |
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| 46 | * You should have received a copy of the GNU General Public License |
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| 47 | * along with this program; if not, write to the Free Software |
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| 48 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 49 | * |
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| 50 | */ |
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| 51 | /* |
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| 52 | * Copyright (c) 1995, 1998-1999 University of Utah and the Flux Group. |
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| 53 | * All rights reserved. |
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| 54 | * |
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| 55 | * This file is part of the Flux OSKit. The OSKit is free software, also known |
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| 56 | * as "open source;" you can redistribute it and/or modify it under the terms |
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| 57 | * of the GNU General Public License (GPL), version 2, as published by the Free |
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| 58 | * Software Foundation (FSF). To explore alternate licensing terms, contact |
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| 59 | * the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271. |
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| 60 | * |
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| 61 | * The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY |
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| 62 | * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
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| 63 | * FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have |
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| 64 | * received a copy of the GPL along with the OSKit; see the file COPYING. If |
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| 65 | * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA. |
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| 66 | */ |
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| 67 | |||
| 68 | #include <kernel/lmm.h> |
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| 69 | #define assert(test) assertk(test) |
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| 70 | |||
| 71 | void lmm_free(lmm_t *lmm, void *block, size_t size) |
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| 72 | { |
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| 73 | struct lmm_region *reg; |
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| 74 | struct lmm_node *node = (struct lmm_node*) |
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| 75 | ((DWORD)block & ~ALIGN_MASK); |
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| 76 | struct lmm_node *prevnode, *nextnode; |
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| 77 | |||
| 78 | assert(lmm != 0); |
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| 79 | assert(block != 0); |
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| 80 | assert(size > 0); |
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| 81 | |||
| 82 | size = (((DWORD)block & ALIGN_MASK) + size + ALIGN_MASK) |
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| 83 | & ~ALIGN_MASK; |
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| 84 | |||
| 85 | /* First find the region to add this block to. */ |
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| 86 | for (reg = lmm->regions; ; reg = reg->next) |
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| 87 | { |
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| 88 | assert(reg != 0); |
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| 89 | CHECKREGPTR(reg); |
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| 90 | |||
| 91 | if (((DWORD)node >= reg->min) |
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| 92 | && ((DWORD)node < reg->max)) |
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| 93 | break; |
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| 94 | } |
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| 95 | |||
| 96 | /* Record the newly freed space in the region's free space counter. */ |
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| 97 | reg->free += size; |
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| 98 | assert(reg->free <= reg->max - reg->min); |
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| 99 | |||
| 100 | /* Now find the location in that region's free list |
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| 101 | at which to add the node. */ |
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| 102 | for (prevnode = 0, nextnode = reg->nodes; |
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| 103 | (nextnode != 0) && (nextnode < node); |
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| 104 | prevnode = nextnode, nextnode = nextnode->next); |
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| 105 | |||
| 106 | /* Coalesce the new free chunk into the previous chunk if possible. */ |
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| 107 | if ((prevnode) && |
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| 108 | ((DWORD)prevnode + prevnode->size >= (DWORD)node)) |
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| 109 | { |
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| 110 | assert((DWORD)prevnode + prevnode->size |
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| 111 | == (DWORD)node); |
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| 112 | |||
| 113 | /* Coalesce prevnode with nextnode if possible. */ |
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| 114 | if (((DWORD)nextnode) |
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| 115 | && ((DWORD)node + size >= (DWORD)nextnode)) |
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| 116 | { |
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| 117 | assert((DWORD)node + size |
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| 118 | == (DWORD)nextnode); |
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| 119 | |||
| 120 | prevnode->size += size + nextnode->size; |
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| 121 | prevnode->next = nextnode->next; |
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| 122 | } |
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| 123 | else |
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| 124 | { |
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| 125 | /* Not possible - |
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| 126 | just grow prevnode around newly freed memory. */ |
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| 127 | prevnode->size += size; |
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| 128 | } |
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| 129 | } |
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| 130 | else |
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| 131 | { |
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| 132 | /* Insert the new node into the free list. */ |
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| 133 | if (prevnode) |
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| 134 | prevnode->next = node; |
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| 135 | else |
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| 136 | reg->nodes = node; |
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| 137 | |||
| 138 | /* Try coalescing the new node with the nextnode. */ |
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| 139 | if ((nextnode) && |
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| 140 | (DWORD)node + size >= (DWORD)nextnode) |
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| 141 | { |
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| 142 | node->size = size + nextnode->size; |
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| 143 | node->next = nextnode->next; |
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| 144 | } |
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| 145 | else |
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| 146 | { |
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| 147 | node->size = size; |
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| 148 | node->next = nextnode; |
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| 149 | } |
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| 150 | } |
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| 151 | } |
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| 152 |