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