sys/dev/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  * __FBSDID("$FreeBSD: src/sys/dev/drm/drm_mm.c,v 1.1 2010/01/31 14:25:29 rnoland Exp $");
  28  **************************************************************************/
  29
  30 /*
  31  * Generic simple memory manager implementation. Intended to be used as a base
  32  * class implementation for more advanced memory managers.
  33  *
  34  * Note that the algorithm used is quite simple and there might be substantial
  35  * performance gains if a smarter free list is implemented. Currently it is just an
  36  * unordered stack of free regions. This could easily be improved if an RB-tree
  37  * is used instead. At least if we expect heavy fragmentation.
  38  *
  39  * Aligned allocations can also see improvement.
  40  *
  41  * Authors:
  42  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  43  */
  44
  45 #include "dev/drm/drmP.h"
  46 #include "dev/drm/drm_mm.h"
  47
  48 #define MM_UNUSED_TARGET 4
  49
  50 unsigned long drm_mm_tail_space(struct drm_mm *mm)
  51 {
  52         struct list_head *tail_node;
  53         struct drm_mm_node *entry;
  54
  55         tail_node = mm->ml_entry.prev;
  56         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  57         if (!entry->free)
  58                 return 0;
  59
  60         return entry->size;
  61 }
  62
  63 int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
  64 {
  65         struct list_head *tail_node;
  66         struct drm_mm_node *entry;
  67
  68         tail_node = mm->ml_entry.prev;
  69         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  70         if (!entry->free)
  71                 return -ENOMEM;
  72
  73         if (entry->size <= size)
  74                 return -ENOMEM;
  75
  76         entry->size -= size;
  77         return 0;
  78 }
  79
  80 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
  81 {
  82         struct drm_mm_node *child;
  83
  84         if (atomic)
  85                 child = malloc(sizeof(*child), DRM_MEM_MM, M_NOWAIT);
  86         else
  87                 child = malloc(sizeof(*child), DRM_MEM_MM, M_WAITOK);
  88
  89         if (unlikely(child == NULL)) {
  90                 DRM_SPINLOCK(&mm->unused_lock);
  91                 if (list_empty(&mm->unused_nodes))
  92                         child = NULL;
  93                 else {
  94                         child =
  95                             list_entry(mm->unused_nodes.next,
  96                                        struct drm_mm_node, fl_entry);
  97                         list_del(&child->fl_entry);
  98                         --mm->num_unused;
  99                 }
 100                 DRM_SPINUNLOCK(&mm->unused_lock);
 101         }
 102         return child;
 103 }
 104
 105 int drm_mm_pre_get(struct drm_mm *mm)
 106 {
 107         struct drm_mm_node *node;
 108
 109         DRM_SPINLOCK(&mm->unused_lock);
 110         while (mm->num_unused < MM_UNUSED_TARGET) {
 111                 DRM_SPINUNLOCK(&mm->unused_lock);
 112                 node = malloc(sizeof(*node), DRM_MEM_MM, M_WAITOK);
 113                 DRM_SPINLOCK(&mm->unused_lock);
 114
 115                 if (unlikely(node == NULL)) {
 116                         int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
 117                         DRM_SPINUNLOCK(&mm->unused_lock);
 118                         return ret;
 119                 }
 120                 ++mm->num_unused;
 121                 list_add_tail(&node->fl_entry, &mm->unused_nodes);
 122         }
 123         DRM_SPINUNLOCK(&mm->unused_lock);
 124         return 0;
 125 }
 126
 127 static int drm_mm_create_tail_node(struct drm_mm *mm,
 128                                    unsigned long start,
 129                                    unsigned long size, int atomic)
 130 {
 131         struct drm_mm_node *child;
 132
 133         child = drm_mm_kmalloc(mm, atomic);
 134         if (unlikely(child == NULL))
 135                 return -ENOMEM;
 136
 137         child->free = 1;
 138         child->size = size;
 139         child->start = start;
 140         child->mm = mm;
 141
 142         list_add_tail(&child->ml_entry, &mm->ml_entry);
 143         list_add_tail(&child->fl_entry, &mm->fl_entry);
 144
 145         return 0;
 146 }
 147
 148 int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
 149 {
 150         struct list_head *tail_node;
 151         struct drm_mm_node *entry;
 152
 153         tail_node = mm->ml_entry.prev;
 154         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
 155         if (!entry->free) {
 156                 return drm_mm_create_tail_node(mm, entry->start + entry->size,
 157                                                size, atomic);
 158         }
 159         entry->size += size;
 160         return 0;
 161 }
 162
 163 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
 164                                                  unsigned long size,
 165                                                  int atomic)
 166 {
 167         struct drm_mm_node *child;
 168
 169         child = drm_mm_kmalloc(parent->mm, atomic);
 170         if (unlikely(child == NULL))
 171                 return NULL;
 172
 173         INIT_LIST_HEAD(&child->fl_entry);
 174
 175         child->free = 0;
 176         child->size = size;
 177         child->start = parent->start;
 178         child->mm = parent->mm;
 179
 180         list_add_tail(&child->ml_entry, &parent->ml_entry);
 181         INIT_LIST_HEAD(&child->fl_entry);
 182
 183         parent->size -= size;
 184         parent->start += size;
 185         return child;
 186 }
 187
 188
 189 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
 190                                              unsigned long size,
 191                                              unsigned alignment,
 192                                              int atomic)
 193 {
 194
 195         struct drm_mm_node *align_splitoff = NULL;
 196         unsigned tmp = 0;
 197
 198         if (alignment)
 199                 tmp = node->start % alignment;
 200
 201         if (tmp) {
 202                 align_splitoff =
 203                     drm_mm_split_at_start(node, alignment - tmp, atomic);
 204                 if (unlikely(align_splitoff == NULL))
 205                         return NULL;
 206         }
 207
 208         if (node->size == size) {
 209                 list_del_init(&node->fl_entry);
 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
 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->ml_entry;
 231         struct list_head *root_head = &mm->ml_entry;
 232         struct drm_mm_node *prev_node = NULL;
 233         struct drm_mm_node *next_node;
 234
 235         int merged = 0;
 236
 237         if (cur_head->prev != root_head) {
 238                 prev_node =
 239                     list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
 240                 if (prev_node->free) {
 241                         prev_node->size += cur->size;
 242                         merged = 1;
 243                 }
 244         }
 245         if (cur_head->next != root_head) {
 246                 next_node =
 247                     list_entry(cur_head->next, struct drm_mm_node, ml_entry);
 248                 if (next_node->free) {
 249                         if (merged) {
 250                                 prev_node->size += next_node->size;
 251                                 list_del(&next_node->ml_entry);
 252                                 list_del(&next_node->fl_entry);
 253                                 if (mm->num_unused < MM_UNUSED_TARGET) {
 254                                         list_add(&next_node->fl_entry,
 255                                                  &mm->unused_nodes);
 256                                         ++mm->num_unused;
 257                                 } else
 258                                         free(next_node, DRM_MEM_MM);
 259                         } else {
 260                                 next_node->size += cur->size;
 261                                 next_node->start = cur->start;
 262                                 merged = 1;
 263                         }
 264                 }
 265         }
 266         if (!merged) {
 267                 cur->free = 1;
 268                 list_add(&cur->fl_entry, &mm->fl_entry);
 269         } else {
 270                 list_del(&cur->ml_entry);
 271                 if (mm->num_unused < MM_UNUSED_TARGET) {
 272                         list_add(&cur->fl_entry, &mm->unused_nodes);
 273                         ++mm->num_unused;
 274                 } else
 275                         free(cur, DRM_MEM_MM);
 276         }
 277 }
 278
 279 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 280                                        unsigned long size,
 281                                        unsigned alignment, int best_match)
 282 {
 283         struct list_head *list;
 284         const struct list_head *free_stack = &mm->fl_entry;
 285         struct drm_mm_node *entry;
 286         struct drm_mm_node *best;
 287         unsigned long best_size;
 288         unsigned wasted;
 289
 290         best = NULL;
 291         best_size = ~0UL;
 292
 293         list_for_each(list, free_stack) {
 294                 entry = list_entry(list, struct drm_mm_node, fl_entry);
 295                 wasted = 0;
 296
 297                 if (entry->size < size)
 298                         continue;
 299
 300                 if (alignment) {
 301                         register unsigned tmp = entry->start % alignment;
 302                         if (tmp)
 303                                 wasted += alignment - tmp;
 304                 }
 305
 306                 if (entry->size >= size + wasted) {
 307                         if (!best_match)
 308                                 return entry;
 309                         if (size < best_size) {
 310                                 best = entry;
 311                                 best_size = entry->size;
 312                         }
 313                 }
 314         }
 315
 316         return best;
 317 }
 318
 319 int drm_mm_clean(struct drm_mm * mm)
 320 {
 321         struct list_head *head = &mm->ml_entry;
 322
 323         return (head->next->next == head);
 324 }
 325
 326 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 327 {
 328         INIT_LIST_HEAD(&mm->ml_entry);
 329         INIT_LIST_HEAD(&mm->fl_entry);
 330         INIT_LIST_HEAD(&mm->unused_nodes);
 331         mm->num_unused = 0;
 332         DRM_SPININIT(&mm->unused_lock, "drm_unused");
 333
 334         return drm_mm_create_tail_node(mm, start, size, 0);
 335 }
 336
 337 void drm_mm_takedown(struct drm_mm * mm)
 338 {
 339         struct list_head *bnode = mm->fl_entry.next;
 340         struct drm_mm_node *entry;
 341         struct drm_mm_node *next;
 342
 343         entry = list_entry(bnode, struct drm_mm_node, fl_entry);
 344
 345         if (entry->ml_entry.next != &mm->ml_entry ||
 346             entry->fl_entry.next != &mm->fl_entry) {
 347                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 348                 return;
 349         }
 350
 351         list_del(&entry->fl_entry);
 352         list_del(&entry->ml_entry);
 353         free(entry, DRM_MEM_MM);
 354
 355         DRM_SPINLOCK(&mm->unused_lock);
 356         list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) {
 357                 list_del(&entry->fl_entry);
 358                 free(entry, DRM_MEM_MM);
 359                 --mm->num_unused;
 360         }
 361         DRM_SPINUNLOCK(&mm->unused_lock);
 362
 363         DRM_SPINUNINIT(&mm->unused_lock);
 364
 365         KASSERT(mm->num_unused == 0, ("num_unused != 0"));
 366 }