Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 1 | /************************************************************************** |
| 2 | * |
| 3 | * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA. |
| 4 | * All Rights Reserved. |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a |
| 7 | * copy of this software and associated documentation files (the |
| 8 | * "Software"), to deal in the Software without restriction, including |
| 9 | * without limitation the rights to use, copy, modify, merge, publish, |
| 10 | * distribute, sub license, and/or sell copies of the Software, and to |
| 11 | * permit persons to whom the Software is furnished to do so, subject to |
| 12 | * the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice (including the |
| 15 | * next paragraph) shall be included in all copies or substantial portions |
| 16 | * of the Software. |
| 17 | * |
| 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 20 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
| 21 | * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, |
| 22 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
| 23 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
| 24 | * USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 25 | * |
| 26 | * |
| 27 | **************************************************************************/ |
| 28 | |
| 29 | /* |
| 30 | * Generic simple memory manager implementation. Intended to be used as a base |
| 31 | * class implementation for more advanced memory managers. |
| 32 | * |
| 33 | * Note that the algorithm used is quite simple and there might be substantial |
| 34 | * performance gains if a smarter free list is implemented. Currently it is just an |
| 35 | * unordered stack of free regions. This could easily be improved if an RB-tree |
| 36 | * is used instead. At least if we expect heavy fragmentation. |
| 37 | * |
| 38 | * Aligned allocations can also see improvement. |
| 39 | * |
| 40 | * Authors: |
| 41 | * Thomas Hellström <thomas-at-tungstengraphics-dot-com> |
| 42 | */ |
| 43 | |
| 44 | #include "drmP.h" |
| 45 | |
| 46 | drm_mm_node_t *drm_mm_get_block(drm_mm_node_t * parent, |
| 47 | unsigned long size, unsigned alignment) |
| 48 | { |
| 49 | |
| 50 | drm_mm_node_t *child; |
| 51 | |
| 52 | if (alignment) |
| 53 | size += alignment - 1; |
| 54 | |
| 55 | if (parent->size == size) { |
| 56 | list_del_init(&parent->fl_entry); |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 57 | parent->free = 0; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 58 | return parent; |
| 59 | } else { |
| 60 | child = (drm_mm_node_t *) drm_alloc(sizeof(*child), DRM_MEM_MM); |
| 61 | if (!child) |
| 62 | return NULL; |
| 63 | |
| 64 | INIT_LIST_HEAD(&child->ml_entry); |
| 65 | INIT_LIST_HEAD(&child->fl_entry); |
| 66 | |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 67 | child->free = 0; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 68 | child->size = size; |
| 69 | child->start = parent->start; |
| 70 | |
| 71 | list_add_tail(&child->ml_entry, &parent->ml_entry); |
| 72 | parent->size -= size; |
| 73 | parent->start += size; |
| 74 | } |
| 75 | return child; |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * Put a block. Merge with the previous and / or next block if they are free. |
| 80 | * Otherwise add to the free stack. |
| 81 | */ |
| 82 | |
| 83 | void drm_mm_put_block(drm_mm_t * mm, drm_mm_node_t * cur) |
| 84 | { |
| 85 | |
| 86 | drm_mm_node_t *list_root = &mm->root_node; |
| 87 | struct list_head *cur_head = &cur->ml_entry; |
| 88 | struct list_head *root_head = &list_root->ml_entry; |
| 89 | drm_mm_node_t *prev_node = NULL; |
| 90 | drm_mm_node_t *next_node; |
| 91 | |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 92 | int merged = 0; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 93 | |
| 94 | if (cur_head->prev != root_head) { |
| 95 | prev_node = list_entry(cur_head->prev, drm_mm_node_t, ml_entry); |
| 96 | if (prev_node->free) { |
| 97 | prev_node->size += cur->size; |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 98 | merged = 1; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 99 | } |
| 100 | } |
| 101 | if (cur_head->next != root_head) { |
| 102 | next_node = list_entry(cur_head->next, drm_mm_node_t, ml_entry); |
| 103 | if (next_node->free) { |
| 104 | if (merged) { |
| 105 | prev_node->size += next_node->size; |
| 106 | list_del(&next_node->ml_entry); |
| 107 | list_del(&next_node->fl_entry); |
| 108 | drm_free(next_node, sizeof(*next_node), |
| 109 | DRM_MEM_MM); |
| 110 | } else { |
| 111 | next_node->size += cur->size; |
| 112 | next_node->start = cur->start; |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 113 | merged = 1; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 114 | } |
| 115 | } |
| 116 | } |
| 117 | if (!merged) { |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 118 | cur->free = 1; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 119 | list_add(&cur->fl_entry, &list_root->fl_entry); |
| 120 | } else { |
| 121 | list_del(&cur->ml_entry); |
| 122 | drm_free(cur, sizeof(*cur), DRM_MEM_MM); |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | drm_mm_node_t *drm_mm_search_free(const drm_mm_t * mm, |
| 127 | unsigned long size, |
| 128 | unsigned alignment, int best_match) |
| 129 | { |
| 130 | struct list_head *list; |
| 131 | const struct list_head *free_stack = &mm->root_node.fl_entry; |
| 132 | drm_mm_node_t *entry; |
| 133 | drm_mm_node_t *best; |
| 134 | unsigned long best_size; |
| 135 | |
| 136 | best = NULL; |
| 137 | best_size = ~0UL; |
| 138 | |
| 139 | if (alignment) |
| 140 | size += alignment - 1; |
| 141 | |
| 142 | list_for_each(list, free_stack) { |
| 143 | entry = list_entry(list, drm_mm_node_t, fl_entry); |
| 144 | if (entry->size >= size) { |
| 145 | if (!best_match) |
| 146 | return entry; |
| 147 | if (size < best_size) { |
| 148 | best = entry; |
| 149 | best_size = entry->size; |
| 150 | } |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | return best; |
| 155 | } |
| 156 | |
| 157 | int drm_mm_init(drm_mm_t * mm, unsigned long start, unsigned long size) |
| 158 | { |
| 159 | drm_mm_node_t *child; |
| 160 | |
| 161 | INIT_LIST_HEAD(&mm->root_node.ml_entry); |
| 162 | INIT_LIST_HEAD(&mm->root_node.fl_entry); |
| 163 | child = (drm_mm_node_t *) drm_alloc(sizeof(*child), DRM_MEM_MM); |
| 164 | if (!child) |
| 165 | return -ENOMEM; |
| 166 | |
| 167 | INIT_LIST_HEAD(&child->ml_entry); |
| 168 | INIT_LIST_HEAD(&child->fl_entry); |
| 169 | |
| 170 | child->start = start; |
| 171 | child->size = size; |
Andrew Morton | a1d0fcf | 2006-08-14 11:35:15 +1000 | [diff] [blame] | 172 | child->free = 1; |
Thomas Hellstrom | 3a1bd92 | 2006-08-07 21:30:28 +1000 | [diff] [blame] | 173 | |
| 174 | list_add(&child->fl_entry, &mm->root_node.fl_entry); |
| 175 | list_add(&child->ml_entry, &mm->root_node.ml_entry); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | EXPORT_SYMBOL(drm_mm_init); |
| 181 | |
| 182 | void drm_mm_takedown(drm_mm_t * mm) |
| 183 | { |
| 184 | struct list_head *bnode = mm->root_node.fl_entry.next; |
| 185 | drm_mm_node_t *entry; |
| 186 | |
| 187 | entry = list_entry(bnode, drm_mm_node_t, fl_entry); |
| 188 | |
| 189 | if (entry->ml_entry.next != &mm->root_node.ml_entry || |
| 190 | entry->fl_entry.next != &mm->root_node.fl_entry) { |
| 191 | DRM_ERROR("Memory manager not clean. Delaying takedown\n"); |
| 192 | return; |
| 193 | } |
| 194 | |
| 195 | list_del(&entry->fl_entry); |
| 196 | list_del(&entry->ml_entry); |
| 197 | |
| 198 | drm_free(entry, sizeof(*entry), DRM_MEM_MM); |
| 199 | } |
| 200 | |
| 201 | EXPORT_SYMBOL(drm_mm_takedown); |