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_mm_node(struct drm_mm_node *entry, unsigned long size,
 289                               unsigned alignment)
 290 {
 291         unsigned wasted = 0;
 292
 293         if (entry->size < size)
 294                 return 0;
 295
 296         if (alignment) {
 297                 register unsigned tmp = entry->start % alignment;
 298                 if (tmp)
 299                         wasted = alignment - tmp;
 300         }
 301
 302         if (entry->size >= 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_mm_node(entry, size, alignment))
 324                         continue;
 325
 326                 if (!best_match)
 327                         return entry;
 328
 329                 if (entry->size < best_size) {
 330                         best = entry;
 331                         best_size = entry->size;
 332                 }
 333         }
 334
 335         return best;
 336 }
 337 EXPORT_SYMBOL(drm_mm_search_free);
 338
 339 struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
 340                                                 unsigned long size,
 341                                                 unsigned alignment,
 342                                                 unsigned long start,
 343                                                 unsigned long end,
 344                                                 int best_match)
 345 {
 346         struct drm_mm_node *entry;
 347         struct drm_mm_node *best;
 348         unsigned long best_size;
 349
 350         BUG_ON(mm->scanned_blocks);
 351
 352         best = NULL;
 353         best_size = ~0UL;
 354
 355         list_for_each_entry(entry, &mm->free_stack, free_stack) {
 356                 if (entry->start > end || (entry->start+entry->size) < start)
 357                         continue;
 358
 359                 if (!check_free_mm_node(entry, size, alignment))
 360                         continue;
 361
 362                 if (!best_match)
 363                         return entry;
 364
 365                 if (entry->size < best_size) {
 366                         best = entry;
 367                         best_size = entry->size;
 368                 }
 369         }
 370
 371         return best;
 372 }
 373 EXPORT_SYMBOL(drm_mm_search_free_in_range);
 374
 375 /**
 376  * Initializa lru scanning.
 377  *
 378  * This simply sets up the scanning routines with the parameters for the desired
 379  * hole.
 380  *
 381  * Warning: As long as the scan list is non-empty, no other operations than
 382  * adding/removing nodes to/from the scan list are allowed.
 383  */
 384 void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
 385                       unsigned alignment)
 386 {
 387         mm->scan_alignment = alignment;
 388         mm->scan_size = size;
 389         mm->scanned_blocks = 0;
 390         mm->scan_hit_start = 0;
 391         mm->scan_hit_size = 0;
 392 }
 393 EXPORT_SYMBOL(drm_mm_init_scan);
 394
 395 /**
 396  * Add a node to the scan list that might be freed to make space for the desired
 397  * hole.
 398  *
 399  * Returns non-zero, if a hole has been found, zero otherwise.
 400  */
 401 int drm_mm_scan_add_block(struct drm_mm_node *node)
 402 {
 403         struct drm_mm *mm = node->mm;
 404         struct list_head *prev_free, *next_free;
 405         struct drm_mm_node *prev_node, *next_node;
 406
 407         mm->scanned_blocks++;
 408
 409         prev_free = next_free = NULL;
 410
 411         BUG_ON(node->free);
 412         node->scanned_block = 1;
 413         node->free = 1;
 414
 415         if (node->node_list.prev != &mm->node_list) {
 416                 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
 417                                        node_list);
 418
 419                 if (prev_node->free) {
 420                         list_del(&prev_node->node_list);
 421
 422                         node->start = prev_node->start;
 423                         node->size += prev_node->size;
 424
 425                         prev_node->scanned_prev_free = 1;
 426
 427                         prev_free = &prev_node->free_stack;
 428                 }
 429         }
 430
 431         if (node->node_list.next != &mm->node_list) {
 432                 next_node = list_entry(node->node_list.next, struct drm_mm_node,
 433                                        node_list);
 434
 435                 if (next_node->free) {
 436                         list_del(&next_node->node_list);
 437
 438                         node->size += next_node->size;
 439
 440                         next_node->scanned_next_free = 1;
 441
 442                         next_free = &next_node->free_stack;
 443                 }
 444         }
 445
 446         /* The free_stack list is not used for allocated objects, so these two
 447          * pointers can be abused (as long as no allocations in this memory
 448          * manager happens). */
 449         node->free_stack.prev = prev_free;
 450         node->free_stack.next = next_free;
 451
 452         if (check_free_mm_node(node, mm->scan_size, mm->scan_alignment)) {
 453                 mm->scan_hit_start = node->start;
 454                 mm->scan_hit_size = node->size;
 455
 456                 return 1;
 457         }
 458
 459         return 0;
 460 }
 461 EXPORT_SYMBOL(drm_mm_scan_add_block);
 462
 463 /**
 464  * Remove a node from the scan list.
 465  *
 466  * Nodes _must_ be removed in the exact same order from the scan list as they
 467  * have been added, otherwise the internal state of the memory manager will be
 468  * corrupted.
 469  *
 470  * When the scan list is empty, the selected memory nodes can be freed. An
 471  * immediatly following drm_mm_search_free with best_match = 0 will then return
 472  * the just freed block (because its at the top of the free_stack list).
 473  *
 474  * Returns one if this block should be evicted, zero otherwise. Will always
 475  * return zero when no hole has been found.
 476  */
 477 int drm_mm_scan_remove_block(struct drm_mm_node *node)
 478 {
 479         struct drm_mm *mm = node->mm;
 480         struct drm_mm_node *prev_node, *next_node;
 481
 482         mm->scanned_blocks--;
 483
 484         BUG_ON(!node->scanned_block);
 485         node->scanned_block = 0;
 486         node->free = 0;
 487
 488         prev_node = list_entry(node->free_stack.prev, struct drm_mm_node,
 489                                free_stack);
 490         next_node = list_entry(node->free_stack.next, struct drm_mm_node,
 491                                free_stack);
 492
 493         if (prev_node) {
 494                 BUG_ON(!prev_node->scanned_prev_free);
 495                 prev_node->scanned_prev_free = 0;
 496
 497                 list_add_tail(&prev_node->node_list, &node->node_list);
 498
 499                 node->start = prev_node->start + prev_node->size;
 500                 node->size -= prev_node->size;
 501         }
 502
 503         if (next_node) {
 504                 BUG_ON(!next_node->scanned_next_free);
 505                 next_node->scanned_next_free = 0;
 506
 507                 list_add(&next_node->node_list, &node->node_list);
 508
 509                 node->size -= next_node->size;
 510         }
 511
 512         INIT_LIST_HEAD(&node->free_stack);
 513
 514         /* Only need to check for containement because start&size for the
 515          * complete resulting free block (not just the desired part) is
 516          * stored. */
 517         if (node->start >= mm->scan_hit_start &&
 518             node->start + node->size
 519                         <= mm->scan_hit_start + mm->scan_hit_size) {
 520                 return 1;
 521         }
 522
 523         return 0;
 524 }
 525 EXPORT_SYMBOL(drm_mm_scan_remove_block);
 526
 527 int drm_mm_clean(struct drm_mm * mm)
 528 {
 529         struct list_head *head = &mm->node_list;
 530
 531         return (head->next->next == head);
 532 }
 533 EXPORT_SYMBOL(drm_mm_clean);
 534
 535 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 536 {
 537         INIT_LIST_HEAD(&mm->node_list);
 538         INIT_LIST_HEAD(&mm->free_stack);
 539         INIT_LIST_HEAD(&mm->unused_nodes);
 540         mm->num_unused = 0;
 541         mm->scanned_blocks = 0;
 542         spin_lock_init(&mm->unused_lock);
 543
 544         return drm_mm_create_tail_node(mm, start, size, 0);
 545 }
 546 EXPORT_SYMBOL(drm_mm_init);
 547
 548 void drm_mm_takedown(struct drm_mm * mm)
 549 {
 550         struct list_head *bnode = mm->free_stack.next;
 551         struct drm_mm_node *entry;
 552         struct drm_mm_node *next;
 553
 554         entry = list_entry(bnode, struct drm_mm_node, free_stack);
 555
 556         if (entry->node_list.next != &mm->node_list ||
 557             entry->free_stack.next != &mm->free_stack) {
 558                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 559                 return;
 560         }
 561
 562         list_del(&entry->free_stack);
 563         list_del(&entry->node_list);
 564         kfree(entry);
 565
 566         spin_lock(&mm->unused_lock);
 567         list_for_each_entry_safe(entry, next, &mm->unused_nodes, free_stack) {
 568                 list_del(&entry->free_stack);
 569                 kfree(entry);
 570                 --mm->num_unused;
 571         }
 572         spin_unlock(&mm->unused_lock);
 573
 574         BUG_ON(mm->num_unused != 0);
 575 }
 576 EXPORT_SYMBOL(drm_mm_takedown);
 577
 578 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
 579 {
 580         struct drm_mm_node *entry;
 581         int total_used = 0, total_free = 0, total = 0;
 582
 583         list_for_each_entry(entry, &mm->node_list, node_list) {
 584                 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8ld: %s\n",
 585                         prefix, entry->start, entry->start + entry->size,
 586                         entry->size, entry->free ? "free" : "used");
 587                 total += entry->size;
 588                 if (entry->free)
 589                         total_free += entry->size;
 590                 else
 591                         total_used += entry->size;
 592         }
 593         printk(KERN_DEBUG "%s total: %d, used %d free %d\n", prefix, total,
 594                 total_used, total_free);
 595 }
 596 EXPORT_SYMBOL(drm_mm_debug_table);
 597
 598 #if defined(CONFIG_DEBUG_FS)
 599 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
 600 {
 601         struct drm_mm_node *entry;
 602         int total_used = 0, total_free = 0, total = 0;
 603
 604         list_for_each_entry(entry, &mm->node_list, node_list) {
 605                 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: %s\n", entry->start, entry->start + entry->size, entry->size, entry->free ? "free" : "used");
 606                 total += entry->size;
 607                 if (entry->free)
 608                         total_free += entry->size;
 609                 else
 610                         total_used += entry->size;
 611         }
 612         seq_printf(m, "total: %d, used %d free %d\n", total, total_used, total_free);
 613         return 0;
 614 }
 615 EXPORT_SYMBOL(drm_mm_dump_table);
 616 #endif