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 = kzalloc(sizeof(*child), GFP_ATOMIC);
  57         else
  58                 child = kzalloc(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 = kzalloc(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->size = size;
 138         child->start = parent->start;
 139         child->mm = parent->mm;
 140
 141         list_add_tail(&child->node_list, &parent->node_list);
 142         INIT_LIST_HEAD(&child->free_stack);
 143
 144         parent->size -= size;
 145         parent->start += size;
 146         return child;
 147 }
 148
 149
 150 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
 151                                              unsigned long size,
 152                                              unsigned alignment,
 153                                              int atomic)
 154 {
 155
 156         struct drm_mm_node *align_splitoff = NULL;
 157         unsigned tmp = 0;
 158
 159         if (alignment)
 160                 tmp = node->start % alignment;
 161
 162         if (tmp) {
 163                 align_splitoff =
 164                     drm_mm_split_at_start(node, alignment - tmp, atomic);
 165                 if (unlikely(align_splitoff == NULL))
 166                         return NULL;
 167         }
 168
 169         if (node->size == size) {
 170                 list_del_init(&node->free_stack);
 171                 node->free = 0;
 172         } else {
 173                 node = drm_mm_split_at_start(node, size, atomic);
 174         }
 175
 176         if (align_splitoff)
 177                 drm_mm_put_block(align_splitoff);
 178
 179         return node;
 180 }
 181 EXPORT_SYMBOL(drm_mm_get_block_generic);
 182
 183 struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *node,
 184                                                 unsigned long size,
 185                                                 unsigned alignment,
 186                                                 unsigned long start,
 187                                                 unsigned long end,
 188                                                 int atomic)
 189 {
 190         struct drm_mm_node *align_splitoff = NULL;
 191         unsigned tmp = 0;
 192         unsigned wasted = 0;
 193
 194         if (node->start < start)
 195                 wasted += start - node->start;
 196         if (alignment)
 197                 tmp = ((node->start + wasted) % alignment);
 198
 199         if (tmp)
 200                 wasted += alignment - tmp;
 201         if (wasted) {
 202                 align_splitoff = drm_mm_split_at_start(node, wasted, atomic);
 203                 if (unlikely(align_splitoff == NULL))
 204                         return NULL;
 205         }
 206
 207         if (node->size == size) {
 208                 list_del_init(&node->free_stack);
 209                 node->free = 0;
 210         } else {
 211                 node = drm_mm_split_at_start(node, size, atomic);
 212         }
 213
 214         if (align_splitoff)
 215                 drm_mm_put_block(align_splitoff);
 216
 217         return node;
 218 }
 219 EXPORT_SYMBOL(drm_mm_get_block_range_generic);
 220
 221 /*
 222  * Put a block. Merge with the previous and / or next block if they are free.
 223  * Otherwise add to the free stack.
 224  */
 225
 226 void drm_mm_put_block(struct drm_mm_node *cur)
 227 {
 228
 229         struct drm_mm *mm = cur->mm;
 230         struct list_head *cur_head = &cur->node_list;
 231         struct list_head *root_head = &mm->node_list;
 232         struct drm_mm_node *prev_node = NULL;
 233         struct drm_mm_node *next_node;
 234
 235         int merged = 0;
 236
 237         BUG_ON(cur->scanned_block || cur->scanned_prev_free
 238                                   || cur->scanned_next_free);
 239
 240         if (cur_head->prev != root_head) {
 241                 prev_node =
 242                     list_entry(cur_head->prev, struct drm_mm_node, node_list);
 243                 if (prev_node->free) {
 244                         prev_node->size += cur->size;
 245                         merged = 1;
 246                 }
 247         }
 248         if (cur_head->next != root_head) {
 249                 next_node =
 250                     list_entry(cur_head->next, struct drm_mm_node, node_list);
 251                 if (next_node->free) {
 252                         if (merged) {
 253                                 prev_node->size += next_node->size;
 254                                 list_del(&next_node->node_list);
 255                                 list_del(&next_node->free_stack);
 256                                 spin_lock(&mm->unused_lock);
 257                                 if (mm->num_unused < MM_UNUSED_TARGET) {
 258                                         list_add(&next_node->free_stack,
 259                                                  &mm->unused_nodes);
 260                                         ++mm->num_unused;
 261                                 } else
 262                                         kfree(next_node);
 263                                 spin_unlock(&mm->unused_lock);
 264                         } else {
 265                                 next_node->size += cur->size;
 266                                 next_node->start = cur->start;
 267                                 merged = 1;
 268                         }
 269                 }
 270         }
 271         if (!merged) {
 272                 cur->free = 1;
 273                 list_add(&cur->free_stack, &mm->free_stack);
 274         } else {
 275                 list_del(&cur->node_list);
 276                 spin_lock(&mm->unused_lock);
 277                 if (mm->num_unused < MM_UNUSED_TARGET) {
 278                         list_add(&cur->free_stack, &mm->unused_nodes);
 279                         ++mm->num_unused;
 280                 } else
 281                         kfree(cur);
 282                 spin_unlock(&mm->unused_lock);
 283         }
 284 }
 285
 286 EXPORT_SYMBOL(drm_mm_put_block);
 287
 288 static int check_free_hole(unsigned long start, unsigned long end,
 289                            unsigned long size, unsigned alignment)
 290 {
 291         unsigned wasted = 0;
 292
 293         if (end - start < size)
 294                 return 0;
 295
 296         if (alignment) {
 297                 unsigned tmp = start % alignment;
 298                 if (tmp)
 299                         wasted = alignment - tmp;
 300         }
 301
 302         if (end >= start + size + wasted) {
 303                 return 1;
 304         }
 305
 306         return 0;
 307 }
 308
 309 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 310                                        unsigned long size,
 311                                        unsigned alignment, int best_match)
 312 {
 313         struct drm_mm_node *entry;
 314         struct drm_mm_node *best;
 315         unsigned long best_size;
 316
 317         BUG_ON(mm->scanned_blocks);
 318
 319         best = NULL;
 320         best_size = ~0UL;
 321
 322         list_for_each_entry(entry, &mm->free_stack, free_stack) {
 323                 if (!check_free_hole(entry->start, entry->start + entry->size,
 324                                      size, alignment))
 325                         continue;
 326
 327                 if (!best_match)
 328                         return entry;
 329
 330                 if (entry->size < best_size) {
 331                         best = entry;
 332                         best_size = entry->size;
 333                 }
 334         }
 335
 336         return best;
 337 }
 338 EXPORT_SYMBOL(drm_mm_search_free);
 339
 340 struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
 341                                                 unsigned long size,
 342                                                 unsigned alignment,
 343                                                 unsigned long start,
 344                                                 unsigned long end,
 345                                                 int best_match)
 346 {
 347         struct drm_mm_node *entry;
 348         struct drm_mm_node *best;
 349         unsigned long best_size;
 350
 351         BUG_ON(mm->scanned_blocks);
 352
 353         best = NULL;
 354         best_size = ~0UL;
 355
 356         list_for_each_entry(entry, &mm->free_stack, free_stack) {
 357                 unsigned long adj_start = entry->start < start ?
 358                         start : entry->start;
 359                 unsigned long adj_end = entry->start + entry->size > end ?
 360                         end : entry->start + entry->size;
 361
 362                 if (!check_free_hole(adj_start, adj_end, size, alignment))
 363                         continue;
 364
 365                 if (!best_match)
 366                         return entry;
 367
 368                 if (entry->size < best_size) {
 369                         best = entry;
 370                         best_size = entry->size;
 371                 }
 372         }
 373
 374         return best;
 375 }
 376 EXPORT_SYMBOL(drm_mm_search_free_in_range);
 377
 378 /**
 379  * Initializa lru scanning.
 380  *
 381  * This simply sets up the scanning routines with the parameters for the desired
 382  * hole.
 383  *
 384  * Warning: As long as the scan list is non-empty, no other operations than
 385  * adding/removing nodes to/from the scan list are allowed.
 386  */
 387 void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
 388                       unsigned alignment)
 389 {
 390         mm->scan_alignment = alignment;
 391         mm->scan_size = size;
 392         mm->scanned_blocks = 0;
 393         mm->scan_hit_start = 0;
 394         mm->scan_hit_size = 0;
 395 }
 396 EXPORT_SYMBOL(drm_mm_init_scan);
 397
 398 /**
 399  * Add a node to the scan list that might be freed to make space for the desired
 400  * hole.
 401  *
 402  * Returns non-zero, if a hole has been found, zero otherwise.
 403  */
 404 int drm_mm_scan_add_block(struct drm_mm_node *node)
 405 {
 406         struct drm_mm *mm = node->mm;
 407         struct list_head *prev_free, *next_free;
 408         struct drm_mm_node *prev_node, *next_node;
 409
 410         mm->scanned_blocks++;
 411
 412         prev_free = next_free = NULL;
 413
 414         BUG_ON(node->free);
 415         node->scanned_block = 1;
 416         node->free = 1;
 417
 418         if (node->node_list.prev != &mm->node_list) {
 419                 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
 420                                        node_list);
 421
 422                 if (prev_node->free) {
 423                         list_del(&prev_node->node_list);
 424
 425                         node->start = prev_node->start;
 426                         node->size += prev_node->size;
 427
 428                         prev_node->scanned_prev_free = 1;
 429
 430                         prev_free = &prev_node->free_stack;
 431                 }
 432         }
 433
 434         if (node->node_list.next != &mm->node_list) {
 435                 next_node = list_entry(node->node_list.next, struct drm_mm_node,
 436                                        node_list);
 437
 438                 if (next_node->free) {
 439                         list_del(&next_node->node_list);
 440
 441                         node->size += next_node->size;
 442
 443                         next_node->scanned_next_free = 1;
 444
 445                         next_free = &next_node->free_stack;
 446                 }
 447         }
 448
 449         /* The free_stack list is not used for allocated objects, so these two
 450          * pointers can be abused (as long as no allocations in this memory
 451          * manager happens). */
 452         node->free_stack.prev = prev_free;
 453         node->free_stack.next = next_free;
 454
 455         if (check_free_hole(node->start, node->start + node->size,
 456                             mm->scan_size, mm->scan_alignment)) {
 457                 mm->scan_hit_start = node->start;
 458                 mm->scan_hit_size = node->size;
 459
 460                 return 1;
 461         }
 462
 463         return 0;
 464 }
 465 EXPORT_SYMBOL(drm_mm_scan_add_block);
 466
 467 /**
 468  * Remove a node from the scan list.
 469  *
 470  * Nodes _must_ be removed in the exact same order from the scan list as they
 471  * have been added, otherwise the internal state of the memory manager will be
 472  * corrupted.
 473  *
 474  * When the scan list is empty, the selected memory nodes can be freed. An
 475  * immediatly following drm_mm_search_free with best_match = 0 will then return
 476  * the just freed block (because its at the top of the free_stack list).
 477  *
 478  * Returns one if this block should be evicted, zero otherwise. Will always
 479  * return zero when no hole has been found.
 480  */
 481 int drm_mm_scan_remove_block(struct drm_mm_node *node)
 482 {
 483         struct drm_mm *mm = node->mm;
 484         struct drm_mm_node *prev_node, *next_node;
 485
 486         mm->scanned_blocks--;
 487
 488         BUG_ON(!node->scanned_block);
 489         node->scanned_block = 0;
 490         node->free = 0;
 491
 492         prev_node = list_entry(node->free_stack.prev, struct drm_mm_node,
 493                                free_stack);
 494         next_node = list_entry(node->free_stack.next, struct drm_mm_node,
 495                                free_stack);
 496
 497         if (prev_node) {
 498                 BUG_ON(!prev_node->scanned_prev_free);
 499                 prev_node->scanned_prev_free = 0;
 500
 501                 list_add_tail(&prev_node->node_list, &node->node_list);
 502
 503                 node->start = prev_node->start + prev_node->size;
 504                 node->size -= prev_node->size;
 505         }
 506
 507         if (next_node) {
 508                 BUG_ON(!next_node->scanned_next_free);
 509                 next_node->scanned_next_free = 0;
 510
 511                 list_add(&next_node->node_list, &node->node_list);
 512
 513                 node->size -= next_node->size;
 514         }
 515
 516         INIT_LIST_HEAD(&node->free_stack);
 517
 518         /* Only need to check for containement because start&size for the
 519          * complete resulting free block (not just the desired part) is
 520          * stored. */
 521         if (node->start >= mm->scan_hit_start &&
 522             node->start + node->size
 523                         <= mm->scan_hit_start + mm->scan_hit_size) {
 524                 return 1;
 525         }
 526
 527         return 0;
 528 }
 529 EXPORT_SYMBOL(drm_mm_scan_remove_block);
 530
 531 int drm_mm_clean(struct drm_mm * mm)
 532 {
 533         struct list_head *head = &mm->node_list;
 534
 535         return (head->next->next == head);
 536 }
 537 EXPORT_SYMBOL(drm_mm_clean);
 538
 539 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 540 {
 541         INIT_LIST_HEAD(&mm->node_list);
 542         INIT_LIST_HEAD(&mm->free_stack);
 543         INIT_LIST_HEAD(&mm->unused_nodes);
 544         mm->num_unused = 0;
 545         mm->scanned_blocks = 0;
 546         spin_lock_init(&mm->unused_lock);
 547
 548         return drm_mm_create_tail_node(mm, start, size, 0);
 549 }
 550 EXPORT_SYMBOL(drm_mm_init);
 551
 552 void drm_mm_takedown(struct drm_mm * mm)
 553 {
 554         struct list_head *bnode = mm->free_stack.next;
 555         struct drm_mm_node *entry;
 556         struct drm_mm_node *next;
 557
 558         entry = list_entry(bnode, struct drm_mm_node, free_stack);
 559
 560         if (entry->node_list.next != &mm->node_list ||
 561             entry->free_stack.next != &mm->free_stack) {
 562                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 563                 return;
 564         }
 565
 566         list_del(&entry->free_stack);
 567         list_del(&entry->node_list);
 568         kfree(entry);
 569
 570         spin_lock(&mm->unused_lock);
 571         list_for_each_entry_safe(entry, next, &mm->unused_nodes, free_stack) {
 572                 list_del(&entry->free_stack);
 573                 kfree(entry);
 574                 --mm->num_unused;
 575         }
 576         spin_unlock(&mm->unused_lock);
 577
 578         BUG_ON(mm->num_unused != 0);
 579 }
 580 EXPORT_SYMBOL(drm_mm_takedown);
 581
 582 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
 583 {
 584         struct drm_mm_node *entry;
 585         int total_used = 0, total_free = 0, total = 0;
 586
 587         list_for_each_entry(entry, &mm->node_list, node_list) {
 588                 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8ld: %s\n",
 589                         prefix, entry->start, entry->start + entry->size,
 590                         entry->size, entry->free ? "free" : "used");
 591                 total += entry->size;
 592                 if (entry->free)
 593                         total_free += entry->size;
 594                 else
 595                         total_used += entry->size;
 596         }
 597         printk(KERN_DEBUG "%s total: %d, used %d free %d\n", prefix, total,
 598                 total_used, total_free);
 599 }
 600 EXPORT_SYMBOL(drm_mm_debug_table);
 601
 602 #if defined(CONFIG_DEBUG_FS)
 603 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
 604 {
 605         struct drm_mm_node *entry;
 606         int total_used = 0, total_free = 0, total = 0;
 607
 608         list_for_each_entry(entry, &mm->node_list, node_list) {
 609                 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: %s\n", entry->start, entry->start + entry->size, entry->size, entry->free ? "free" : "used");
 610                 total += entry->size;
 611                 if (entry->free)
 612                         total_free += entry->size;
 613                 else
 614                         total_used += entry->size;
 615         }
 616         seq_printf(m, "total: %d, used %d free %d\n", total, total_used, total_free);
 617         return 0;
 618 }
 619 EXPORT_SYMBOL(drm_mm_dump_table);
 620 #endif