git.oblomov.eu Git - linux-2.6/blob - drivers/gpu/drm/drm_mm.c

   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 #include "drm_mm.h"
  46 #include <linux/slab.h>
  47
  48 #define MM_UNUSED_TARGET 4
  49
  50 unsigned long drm_mm_tail_space(struct drm_mm *mm)
  51 {
  52         struct list_head *tail_node;
  53         struct drm_mm_node *entry;
  54
  55         tail_node = mm->ml_entry.prev;
  56         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  57         if (!entry->free)
  58                 return 0;
  59
  60         return entry->size;
  61 }
  62
  63 int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
  64 {
  65         struct list_head *tail_node;
  66         struct drm_mm_node *entry;
  67
  68         tail_node = mm->ml_entry.prev;
  69         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  70         if (!entry->free)
  71                 return -ENOMEM;
  72
  73         if (entry->size <= size)
  74                 return -ENOMEM;
  75
  76         entry->size -= size;
  77         return 0;
  78 }
  79
  80 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
  81 {
  82         struct drm_mm_node *child;
  83
  84         if (atomic)
  85                 child = kmalloc(sizeof(*child), GFP_ATOMIC);
  86         else
  87                 child = kmalloc(sizeof(*child), GFP_KERNEL);
  88
  89         if (unlikely(child == NULL)) {
  90                 spin_lock(&mm->unused_lock);
  91                 if (list_empty(&mm->unused_nodes))
  92                         child = NULL;
  93                 else {
  94                         child =
  95                             list_entry(mm->unused_nodes.next,
  96                                        struct drm_mm_node, fl_entry);
  97                         list_del(&child->fl_entry);
  98                         --mm->num_unused;
  99                 }
 100                 spin_unlock(&mm->unused_lock);
 101         }
 102         return child;
 103 }
 104
 105 int drm_mm_pre_get(struct drm_mm *mm)
 106 {
 107         struct drm_mm_node *node;
 108
 109         spin_lock(&mm->unused_lock);
 110         while (mm->num_unused < MM_UNUSED_TARGET) {
 111                 spin_unlock(&mm->unused_lock);
 112                 node = kmalloc(sizeof(*node), GFP_KERNEL);
 113                 spin_lock(&mm->unused_lock);
 114
 115                 if (unlikely(node == NULL)) {
 116                         int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
 117                         spin_unlock(&mm->unused_lock);
 118                         return ret;
 119                 }
 120                 ++mm->num_unused;
 121                 list_add_tail(&node->fl_entry, &mm->unused_nodes);
 122         }
 123         spin_unlock(&mm->unused_lock);
 124         return 0;
 125 }
 126 EXPORT_SYMBOL(drm_mm_pre_get);
 127
 128 static int drm_mm_create_tail_node(struct drm_mm *mm,
 129                                    unsigned long start,
 130                                    unsigned long size, int atomic)
 131 {
 132         struct drm_mm_node *child;
 133
 134         child = drm_mm_kmalloc(mm, atomic);
 135         if (unlikely(child == NULL))
 136                 return -ENOMEM;
 137
 138         child->free = 1;
 139         child->size = size;
 140         child->start = start;
 141         child->mm = mm;
 142
 143         list_add_tail(&child->ml_entry, &mm->ml_entry);
 144         list_add_tail(&child->fl_entry, &mm->fl_entry);
 145
 146         return 0;
 147 }
 148
 149 int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
 150 {
 151         struct list_head *tail_node;
 152         struct drm_mm_node *entry;
 153
 154         tail_node = mm->ml_entry.prev;
 155         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
 156         if (!entry->free) {
 157                 return drm_mm_create_tail_node(mm, entry->start + entry->size,
 158                                                size, atomic);
 159         }
 160         entry->size += size;
 161         return 0;
 162 }
 163
 164 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
 165                                                  unsigned long size,
 166                                                  int atomic)
 167 {
 168         struct drm_mm_node *child;
 169
 170         child = drm_mm_kmalloc(parent->mm, atomic);
 171         if (unlikely(child == NULL))
 172                 return NULL;
 173
 174         INIT_LIST_HEAD(&child->fl_entry);
 175
 176         child->free = 0;
 177         child->size = size;
 178         child->start = parent->start;
 179         child->mm = parent->mm;
 180
 181         list_add_tail(&child->ml_entry, &parent->ml_entry);
 182         INIT_LIST_HEAD(&child->fl_entry);
 183
 184         parent->size -= size;
 185         parent->start += size;
 186         return child;
 187 }
 188
 189
 190
 191 struct drm_mm_node *drm_mm_get_block(struct drm_mm_node *node,
 192                                      unsigned long size, unsigned alignment)
 193 {
 194
 195         struct drm_mm_node *align_splitoff = NULL;
 196         unsigned tmp = 0;
 197
 198         if (alignment)
 199                 tmp = node->start % alignment;
 200
 201         if (tmp) {
 202                 align_splitoff =
 203                     drm_mm_split_at_start(node, alignment - tmp, 0);
 204                 if (unlikely(align_splitoff == NULL))
 205                         return NULL;
 206         }
 207
 208         if (node->size == size) {
 209                 list_del_init(&node->fl_entry);
 210                 node->free = 0;
 211         } else {
 212                 node = drm_mm_split_at_start(node, size, 0);
 213         }
 214
 215         if (align_splitoff)
 216                 drm_mm_put_block(align_splitoff);
 217
 218         return node;
 219 }
 220
 221 EXPORT_SYMBOL(drm_mm_get_block);
 222
 223 struct drm_mm_node *drm_mm_get_block_atomic(struct drm_mm_node *parent,
 224                                             unsigned long size,
 225                                             unsigned alignment)
 226 {
 227
 228         struct drm_mm_node *align_splitoff = NULL;
 229         struct drm_mm_node *child;
 230         unsigned tmp = 0;
 231
 232         if (alignment)
 233                 tmp = parent->start % alignment;
 234
 235         if (tmp) {
 236                 align_splitoff =
 237                     drm_mm_split_at_start(parent, alignment - tmp, 1);
 238                 if (unlikely(align_splitoff == NULL))
 239                         return NULL;
 240         }
 241
 242         if (parent->size == size) {
 243                 list_del_init(&parent->fl_entry);
 244                 parent->free = 0;
 245                 return parent;
 246         } else {
 247                 child = drm_mm_split_at_start(parent, size, 1);
 248         }
 249
 250         if (align_splitoff)
 251                 drm_mm_put_block(align_splitoff);
 252
 253         return child;
 254 }
 255 EXPORT_SYMBOL(drm_mm_get_block_atomic);
 256
 257 /*
 258  * Put a block. Merge with the previous and / or next block if they are free.
 259  * Otherwise add to the free stack.
 260  */
 261
 262 void drm_mm_put_block(struct drm_mm_node *cur)
 263 {
 264
 265         struct drm_mm *mm = cur->mm;
 266         struct list_head *cur_head = &cur->ml_entry;
 267         struct list_head *root_head = &mm->ml_entry;
 268         struct drm_mm_node *prev_node = NULL;
 269         struct drm_mm_node *next_node;
 270
 271         int merged = 0;
 272
 273         if (cur_head->prev != root_head) {
 274                 prev_node =
 275                     list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
 276                 if (prev_node->free) {
 277                         prev_node->size += cur->size;
 278                         merged = 1;
 279                 }
 280         }
 281         if (cur_head->next != root_head) {
 282                 next_node =
 283                     list_entry(cur_head->next, struct drm_mm_node, ml_entry);
 284                 if (next_node->free) {
 285                         if (merged) {
 286                                 prev_node->size += next_node->size;
 287                                 list_del(&next_node->ml_entry);
 288                                 list_del(&next_node->fl_entry);
 289                                 if (mm->num_unused < MM_UNUSED_TARGET) {
 290                                         list_add(&next_node->fl_entry,
 291                                                  &mm->unused_nodes);
 292                                         ++mm->num_unused;
 293                                 } else
 294                                         kfree(next_node);
 295                         } else {
 296                                 next_node->size += cur->size;
 297                                 next_node->start = cur->start;
 298                                 merged = 1;
 299                         }
 300                 }
 301         }
 302         if (!merged) {
 303                 cur->free = 1;
 304                 list_add(&cur->fl_entry, &mm->fl_entry);
 305         } else {
 306                 list_del(&cur->ml_entry);
 307                 if (mm->num_unused < MM_UNUSED_TARGET) {
 308                         list_add(&cur->fl_entry, &mm->unused_nodes);
 309                         ++mm->num_unused;
 310                 } else
 311                         kfree(cur);
 312         }
 313 }
 314
 315 EXPORT_SYMBOL(drm_mm_put_block);
 316
 317 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 318                                        unsigned long size,
 319                                        unsigned alignment, int best_match)
 320 {
 321         struct list_head *list;
 322         const struct list_head *free_stack = &mm->fl_entry;
 323         struct drm_mm_node *entry;
 324         struct drm_mm_node *best;
 325         unsigned long best_size;
 326         unsigned wasted;
 327
 328         best = NULL;
 329         best_size = ~0UL;
 330
 331         list_for_each(list, free_stack) {
 332                 entry = list_entry(list, struct drm_mm_node, fl_entry);
 333                 wasted = 0;
 334
 335                 if (entry->size < size)
 336                         continue;
 337
 338                 if (alignment) {
 339                         register unsigned tmp = entry->start % alignment;
 340                         if (tmp)
 341                                 wasted += alignment - tmp;
 342                 }
 343
 344                 if (entry->size >= size + wasted) {
 345                         if (!best_match)
 346                                 return entry;
 347                         if (size < best_size) {
 348                                 best = entry;
 349                                 best_size = entry->size;
 350                         }
 351                 }
 352         }
 353
 354         return best;
 355 }
 356 EXPORT_SYMBOL(drm_mm_search_free);
 357
 358 int drm_mm_clean(struct drm_mm * mm)
 359 {
 360         struct list_head *head = &mm->ml_entry;
 361
 362         return (head->next->next == head);
 363 }
 364 EXPORT_SYMBOL(drm_mm_clean);
 365
 366 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 367 {
 368         INIT_LIST_HEAD(&mm->ml_entry);
 369         INIT_LIST_HEAD(&mm->fl_entry);
 370         INIT_LIST_HEAD(&mm->unused_nodes);
 371         mm->num_unused = 0;
 372         spin_lock_init(&mm->unused_lock);
 373
 374         return drm_mm_create_tail_node(mm, start, size, 0);
 375 }
 376 EXPORT_SYMBOL(drm_mm_init);
 377
 378 void drm_mm_takedown(struct drm_mm * mm)
 379 {
 380         struct list_head *bnode = mm->fl_entry.next;
 381         struct drm_mm_node *entry;
 382         struct drm_mm_node *next;
 383
 384         entry = list_entry(bnode, struct drm_mm_node, fl_entry);
 385
 386         if (entry->ml_entry.next != &mm->ml_entry ||
 387             entry->fl_entry.next != &mm->fl_entry) {
 388                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 389                 return;
 390         }
 391
 392         list_del(&entry->fl_entry);
 393         list_del(&entry->ml_entry);
 394         kfree(entry);
 395
 396         spin_lock(&mm->unused_lock);
 397         list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) {
 398                 list_del(&entry->fl_entry);
 399                 kfree(entry);
 400                 --mm->num_unused;
 401         }
 402         spin_unlock(&mm->unused_lock);
 403
 404         BUG_ON(mm->num_unused != 0);
 405 }
 406 EXPORT_SYMBOL(drm_mm_takedown);