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