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 #include <linux/seq_file.h>
  48
  49 #define MM_UNUSED_TARGET 4
  50
  51 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
  52 {
  53         struct drm_mm_node *child;
  54
  55         if (atomic)
  56                 child = kmalloc(sizeof(*child), GFP_ATOMIC);
  57         else
  58                 child = kmalloc(sizeof(*child), GFP_KERNEL);
  59
  60         if (unlikely(child == NULL)) {
  61                 spin_lock(&mm->unused_lock);
  62                 if (list_empty(&mm->unused_nodes))
  63                         child = NULL;
  64                 else {
  65                         child =
  66                             list_entry(mm->unused_nodes.next,
  67                                        struct drm_mm_node, free_stack);
  68                         list_del(&child->free_stack);
  69                         --mm->num_unused;
  70                 }
  71                 spin_unlock(&mm->unused_lock);
  72         }
  73         return child;
  74 }
  75
  76 /* drm_mm_pre_get() - pre allocate drm_mm_node structure
  77  * drm_mm:      memory manager struct we are pre-allocating for
  78  *
  79  * Returns 0 on success or -ENOMEM if allocation fails.
  80  */
  81 int drm_mm_pre_get(struct drm_mm *mm)
  82 {
  83         struct drm_mm_node *node;
  84
  85         spin_lock(&mm->unused_lock);
  86         while (mm->num_unused < MM_UNUSED_TARGET) {
  87                 spin_unlock(&mm->unused_lock);
  88                 node = kmalloc(sizeof(*node), GFP_KERNEL);
  89                 spin_lock(&mm->unused_lock);
  90
  91                 if (unlikely(node == NULL)) {
  92                         int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
  93                         spin_unlock(&mm->unused_lock);
  94                         return ret;
  95                 }
  96                 ++mm->num_unused;
  97                 list_add_tail(&node->free_stack, &mm->unused_nodes);
  98         }
  99         spin_unlock(&mm->unused_lock);
 100         return 0;
 101 }
 102 EXPORT_SYMBOL(drm_mm_pre_get);
 103
 104 static int drm_mm_create_tail_node(struct drm_mm *mm,
 105                                    unsigned long start,
 106                                    unsigned long size, int atomic)
 107 {
 108         struct drm_mm_node *child;
 109
 110         child = drm_mm_kmalloc(mm, atomic);
 111         if (unlikely(child == NULL))
 112                 return -ENOMEM;
 113
 114         child->free = 1;
 115         child->size = size;
 116         child->start = start;
 117         child->mm = mm;
 118
 119         list_add_tail(&child->node_list, &mm->node_list);
 120         list_add_tail(&child->free_stack, &mm->free_stack);
 121
 122         return 0;
 123 }
 124
 125 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
 126                                                  unsigned long size,
 127                                                  int atomic)
 128 {
 129         struct drm_mm_node *child;
 130
 131         child = drm_mm_kmalloc(parent->mm, atomic);
 132         if (unlikely(child == NULL))
 133                 return NULL;
 134
 135         INIT_LIST_HEAD(&child->free_stack);
 136
 137         child->free = 0;
 138         child->size = size;
 139         child->start = parent->start;
 140         child->mm = parent->mm;
 141
 142         list_add_tail(&child->node_list, &parent->node_list);
 143         INIT_LIST_HEAD(&child->free_stack);
 144
 145         parent->size -= size;
 146         parent->start += size;
 147         return child;
 148 }
 149
 150
 151 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
 152                                              unsigned long size,
 153                                              unsigned alignment,
 154                                              int atomic)
 155 {
 156
 157         struct drm_mm_node *align_splitoff = NULL;
 158         unsigned tmp = 0;
 159
 160         if (alignment)
 161                 tmp = node->start % alignment;
 162
 163         if (tmp) {
 164                 align_splitoff =
 165                     drm_mm_split_at_start(node, alignment - tmp, atomic);
 166                 if (unlikely(align_splitoff == NULL))
 167                         return NULL;
 168         }
 169
 170         if (node->size == size) {
 171                 list_del_init(&node->free_stack);
 172                 node->free = 0;
 173         } else {
 174                 node = drm_mm_split_at_start(node, size, atomic);
 175         }
 176
 177         if (align_splitoff)
 178                 drm_mm_put_block(align_splitoff);
 179
 180         return node;
 181 }
 182 EXPORT_SYMBOL(drm_mm_get_block_generic);
 183
 184 struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *node,
 185                                                 unsigned long size,
 186                                                 unsigned alignment,
 187                                                 unsigned long start,
 188                                                 unsigned long end,
 189                                                 int atomic)
 190 {
 191         struct drm_mm_node *align_splitoff = NULL;
 192         unsigned tmp = 0;
 193         unsigned wasted = 0;
 194
 195         if (node->start < start)
 196                 wasted += start - node->start;
 197         if (alignment)
 198                 tmp = ((node->start + wasted) % alignment);
 199
 200         if (tmp)
 201                 wasted += alignment - tmp;
 202         if (wasted) {
 203                 align_splitoff = drm_mm_split_at_start(node, wasted, atomic);
 204                 if (unlikely(align_splitoff == NULL))
 205                         return NULL;
 206         }
 207
 208         if (node->size == size) {
 209                 list_del_init(&node->free_stack);
 210                 node->free = 0;
 211         } else {
 212                 node = drm_mm_split_at_start(node, size, atomic);
 213         }
 214
 215         if (align_splitoff)
 216                 drm_mm_put_block(align_splitoff);
 217
 218         return node;
 219 }
 220 EXPORT_SYMBOL(drm_mm_get_block_range_generic);
 221
 222 /*
 223  * Put a block. Merge with the previous and / or next block if they are free.
 224  * Otherwise add to the free stack.
 225  */
 226
 227 void drm_mm_put_block(struct drm_mm_node *cur)
 228 {
 229
 230         struct drm_mm *mm = cur->mm;
 231         struct list_head *cur_head = &cur->node_list;
 232         struct list_head *root_head = &mm->node_list;
 233         struct drm_mm_node *prev_node = NULL;
 234         struct drm_mm_node *next_node;
 235
 236         int merged = 0;
 237
 238         if (cur_head->prev != root_head) {
 239                 prev_node =
 240                     list_entry(cur_head->prev, struct drm_mm_node, node_list);
 241                 if (prev_node->free) {
 242                         prev_node->size += cur->size;
 243                         merged = 1;
 244                 }
 245         }
 246         if (cur_head->next != root_head) {
 247                 next_node =
 248                     list_entry(cur_head->next, struct drm_mm_node, node_list);
 249                 if (next_node->free) {
 250                         if (merged) {
 251                                 prev_node->size += next_node->size;
 252                                 list_del(&next_node->node_list);
 253                                 list_del(&next_node->free_stack);
 254                                 spin_lock(&mm->unused_lock);
 255                                 if (mm->num_unused < MM_UNUSED_TARGET) {
 256                                         list_add(&next_node->free_stack,
 257                                                  &mm->unused_nodes);
 258                                         ++mm->num_unused;
 259                                 } else
 260                                         kfree(next_node);
 261                                 spin_unlock(&mm->unused_lock);
 262                         } else {
 263                                 next_node->size += cur->size;
 264                                 next_node->start = cur->start;
 265                                 merged = 1;
 266                         }
 267                 }
 268         }
 269         if (!merged) {
 270                 cur->free = 1;
 271                 list_add(&cur->free_stack, &mm->free_stack);
 272         } else {
 273                 list_del(&cur->node_list);
 274                 spin_lock(&mm->unused_lock);
 275                 if (mm->num_unused < MM_UNUSED_TARGET) {
 276                         list_add(&cur->free_stack, &mm->unused_nodes);
 277                         ++mm->num_unused;
 278                 } else
 279                         kfree(cur);
 280                 spin_unlock(&mm->unused_lock);
 281         }
 282 }
 283
 284 EXPORT_SYMBOL(drm_mm_put_block);
 285
 286 static int check_free_mm_node(struct drm_mm_node *entry, unsigned long size,
 287                               unsigned alignment)
 288 {
 289         unsigned wasted = 0;
 290
 291         if (entry->size < size)
 292                 return 0;
 293
 294         if (alignment) {
 295                 register unsigned tmp = entry->start % alignment;
 296                 if (tmp)
 297                         wasted = alignment - tmp;
 298         }
 299
 300         if (entry->size >= size + wasted) {
 301                 return 1;
 302         }
 303
 304         return 0;
 305 }
 306
 307 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 308                                        unsigned long size,
 309                                        unsigned alignment, int best_match)
 310 {
 311         struct drm_mm_node *entry;
 312         struct drm_mm_node *best;
 313         unsigned long best_size;
 314
 315         best = NULL;
 316         best_size = ~0UL;
 317
 318         list_for_each_entry(entry, &mm->free_stack, free_stack) {
 319                 if (!check_free_mm_node(entry, size, alignment))
 320                         continue;
 321
 322                 if (!best_match)
 323                         return entry;
 324
 325                 if (entry->size < best_size) {
 326                         best = entry;
 327                         best_size = entry->size;
 328                 }
 329         }
 330
 331         return best;
 332 }
 333 EXPORT_SYMBOL(drm_mm_search_free);
 334
 335 struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
 336                                                 unsigned long size,
 337                                                 unsigned alignment,
 338                                                 unsigned long start,
 339                                                 unsigned long end,
 340                                                 int best_match)
 341 {
 342         struct drm_mm_node *entry;
 343         struct drm_mm_node *best;
 344         unsigned long best_size;
 345
 346         best = NULL;
 347         best_size = ~0UL;
 348
 349         list_for_each_entry(entry, &mm->free_stack, free_stack) {
 350                 if (entry->start > end || (entry->start+entry->size) < start)
 351                         continue;
 352
 353                 if (!check_free_mm_node(entry, size, alignment))
 354                         continue;
 355
 356                 if (!best_match)
 357                         return entry;
 358
 359                 if (entry->size < best_size) {
 360                         best = entry;
 361                         best_size = entry->size;
 362                 }
 363         }
 364
 365         return best;
 366 }
 367 EXPORT_SYMBOL(drm_mm_search_free_in_range);
 368
 369 int drm_mm_clean(struct drm_mm * mm)
 370 {
 371         struct list_head *head = &mm->node_list;
 372
 373         return (head->next->next == head);
 374 }
 375 EXPORT_SYMBOL(drm_mm_clean);
 376
 377 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 378 {
 379         INIT_LIST_HEAD(&mm->node_list);
 380         INIT_LIST_HEAD(&mm->free_stack);
 381         INIT_LIST_HEAD(&mm->unused_nodes);
 382         mm->num_unused = 0;
 383         spin_lock_init(&mm->unused_lock);
 384
 385         return drm_mm_create_tail_node(mm, start, size, 0);
 386 }
 387 EXPORT_SYMBOL(drm_mm_init);
 388
 389 void drm_mm_takedown(struct drm_mm * mm)
 390 {
 391         struct list_head *bnode = mm->free_stack.next;
 392         struct drm_mm_node *entry;
 393         struct drm_mm_node *next;
 394
 395         entry = list_entry(bnode, struct drm_mm_node, free_stack);
 396
 397         if (entry->node_list.next != &mm->node_list ||
 398             entry->free_stack.next != &mm->free_stack) {
 399                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 400                 return;
 401         }
 402
 403         list_del(&entry->free_stack);
 404         list_del(&entry->node_list);
 405         kfree(entry);
 406
 407         spin_lock(&mm->unused_lock);
 408         list_for_each_entry_safe(entry, next, &mm->unused_nodes, free_stack) {
 409                 list_del(&entry->free_stack);
 410                 kfree(entry);
 411                 --mm->num_unused;
 412         }
 413         spin_unlock(&mm->unused_lock);
 414
 415         BUG_ON(mm->num_unused != 0);
 416 }
 417 EXPORT_SYMBOL(drm_mm_takedown);
 418
 419 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
 420 {
 421         struct drm_mm_node *entry;
 422         int total_used = 0, total_free = 0, total = 0;
 423
 424         list_for_each_entry(entry, &mm->node_list, node_list) {
 425                 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8ld: %s\n",
 426                         prefix, entry->start, entry->start + entry->size,
 427                         entry->size, entry->free ? "free" : "used");
 428                 total += entry->size;
 429                 if (entry->free)
 430                         total_free += entry->size;
 431                 else
 432                         total_used += entry->size;
 433         }
 434         printk(KERN_DEBUG "%s total: %d, used %d free %d\n", prefix, total,
 435                 total_used, total_free);
 436 }
 437 EXPORT_SYMBOL(drm_mm_debug_table);
 438
 439 #if defined(CONFIG_DEBUG_FS)
 440 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
 441 {
 442         struct drm_mm_node *entry;
 443         int total_used = 0, total_free = 0, total = 0;
 444
 445         list_for_each_entry(entry, &mm->node_list, node_list) {
 446                 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: %s\n", entry->start, entry->start + entry->size, entry->size, entry->free ? "free" : "used");
 447                 total += entry->size;
 448                 if (entry->free)
 449                         total_free += entry->size;
 450                 else
 451                         total_used += entry->size;
 452         }
 453         seq_printf(m, "total: %d, used %d free %d\n", total, total_used, total_free);
 454         return 0;
 455 }
 456 EXPORT_SYMBOL(drm_mm_dump_table);
 457 #endif