drivers/gpu/drm/ttm/ttm_page_alloc.c

   1 /*
   2  * Copyright (c) Red Hat Inc.
   3
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the
  12  * next paragraph) shall be included in all copies or substantial portions
  13  * of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  *
  23  * Authors: Dave Airlie <airlied@redhat.com>
  24  *          Jerome Glisse <jglisse@redhat.com>
  25  *          Pauli Nieminen <suokkos@gmail.com>
  26  */
  27
  28 /* simple list based uncached page pool
  29  * - Pool collects resently freed pages for reuse
  30  * - Use page->lru to keep a free list
  31  * - doesn't track currently in use pages
  32  */
  33 #include <linux/list.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/highmem.h>
  36 #include <linux/mm_types.h>
  37 #include <linux/module.h>
  38 #include <linux/mm.h>
  39 #include <linux/seq_file.h> /* for seq_printf */
  40 #include <linux/slab.h>
  41 #include <linux/dma-mapping.h>
  42
  43 #include <linux/atomic.h>
  44
  45 #include "ttm/ttm_bo_driver.h"
  46 #include "ttm/ttm_page_alloc.h"
  47
  48 #ifdef TTM_HAS_AGP
  49 #include <asm/agp.h>
  50 #endif
  51
  52 #define NUM_PAGES_TO_ALLOC              (PAGE_SIZE/sizeof(struct page *))
  53 #define SMALL_ALLOCATION                16
  54 #define FREE_ALL_PAGES                  (~0U)
  55 /* times are in msecs */
  56 #define PAGE_FREE_INTERVAL              1000
  57
  58 /**
  59  * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
  60  *
  61  * @lock: Protects the shared pool from concurrnet access. Must be used with
  62  * irqsave/irqrestore variants because pool allocator maybe called from
  63  * delayed work.
  64  * @fill_lock: Prevent concurrent calls to fill.
  65  * @list: Pool of free uc/wc pages for fast reuse.
  66  * @gfp_flags: Flags to pass for alloc_page.
  67  * @npages: Number of pages in pool.
  68  */
  69 struct ttm_page_pool {
  70         spinlock_t              lock;
  71         bool                    fill_lock;
  72         struct list_head        list;
  73         gfp_t                   gfp_flags;
  74         unsigned                npages;
  75         char                    *name;
  76         unsigned long           nfrees;
  77         unsigned long           nrefills;
  78 };
  79
  80 /**
  81  * Limits for the pool. They are handled without locks because only place where
  82  * they may change is in sysfs store. They won't have immediate effect anyway
  83  * so forcing serialization to access them is pointless.
  84  */
  85
  86 struct ttm_pool_opts {
  87         unsigned        alloc_size;
  88         unsigned        max_size;
  89         unsigned        small;
  90 };
  91
  92 #define NUM_POOLS 4
  93
  94 /**
  95  * struct ttm_pool_manager - Holds memory pools for fst allocation
  96  *
  97  * Manager is read only object for pool code so it doesn't need locking.
  98  *
  99  * @free_interval: minimum number of jiffies between freeing pages from pool.
 100  * @page_alloc_inited: reference counting for pool allocation.
 101  * @work: Work that is used to shrink the pool. Work is only run when there is
 102  * some pages to free.
 103  * @small_allocation: Limit in number of pages what is small allocation.
 104  *
 105  * @pools: All pool objects in use.
 106  **/
 107 struct ttm_pool_manager {
 108         struct kobject          kobj;
 109         struct shrinker         mm_shrink;
 110         struct ttm_pool_opts    options;
 111
 112         union {
 113                 struct ttm_page_pool    pools[NUM_POOLS];
 114                 struct {
 115                         struct ttm_page_pool    wc_pool;
 116                         struct ttm_page_pool    uc_pool;
 117                         struct ttm_page_pool    wc_pool_dma32;
 118                         struct ttm_page_pool    uc_pool_dma32;
 119                 } ;
 120         };
 121 };
 122
 123 static struct attribute ttm_page_pool_max = {
 124         .name = "pool_max_size",
 125         .mode = S_IRUGO | S_IWUSR
 126 };
 127 static struct attribute ttm_page_pool_small = {
 128         .name = "pool_small_allocation",
 129         .mode = S_IRUGO | S_IWUSR
 130 };
 131 static struct attribute ttm_page_pool_alloc_size = {
 132         .name = "pool_allocation_size",
 133         .mode = S_IRUGO | S_IWUSR
 134 };
 135
 136 static struct attribute *ttm_pool_attrs[] = {
 137         &ttm_page_pool_max,
 138         &ttm_page_pool_small,
 139         &ttm_page_pool_alloc_size,
 140         NULL
 141 };
 142
 143 static void ttm_pool_kobj_release(struct kobject *kobj)
 144 {
 145         struct ttm_pool_manager *m =
 146                 container_of(kobj, struct ttm_pool_manager, kobj);
 147         kfree(m);
 148 }
 149
 150 static ssize_t ttm_pool_store(struct kobject *kobj,
 151                 struct attribute *attr, const char *buffer, size_t size)
 152 {
 153         struct ttm_pool_manager *m =
 154                 container_of(kobj, struct ttm_pool_manager, kobj);
 155         int chars;
 156         unsigned val;
 157         chars = sscanf(buffer, "%u", &val);
 158         if (chars == 0)
 159                 return size;
 160
 161         /* Convert kb to number of pages */
 162         val = val / (PAGE_SIZE >> 10);
 163
 164         if (attr == &ttm_page_pool_max)
 165                 m->options.max_size = val;
 166         else if (attr == &ttm_page_pool_small)
 167                 m->options.small = val;
 168         else if (attr == &ttm_page_pool_alloc_size) {
 169                 if (val > NUM_PAGES_TO_ALLOC*8) {
 170                         printk(KERN_ERR TTM_PFX
 171                                "Setting allocation size to %lu "
 172                                "is not allowed. Recommended size is "
 173                                "%lu\n",
 174                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
 175                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 176                         return size;
 177                 } else if (val > NUM_PAGES_TO_ALLOC) {
 178                         printk(KERN_WARNING TTM_PFX
 179                                "Setting allocation size to "
 180                                "larger than %lu is not recommended.\n",
 181                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 182                 }
 183                 m->options.alloc_size = val;
 184         }
 185
 186         return size;
 187 }
 188
 189 static ssize_t ttm_pool_show(struct kobject *kobj,
 190                 struct attribute *attr, char *buffer)
 191 {
 192         struct ttm_pool_manager *m =
 193                 container_of(kobj, struct ttm_pool_manager, kobj);
 194         unsigned val = 0;
 195
 196         if (attr == &ttm_page_pool_max)
 197                 val = m->options.max_size;
 198         else if (attr == &ttm_page_pool_small)
 199                 val = m->options.small;
 200         else if (attr == &ttm_page_pool_alloc_size)
 201                 val = m->options.alloc_size;
 202
 203         val = val * (PAGE_SIZE >> 10);
 204
 205         return snprintf(buffer, PAGE_SIZE, "%u\n", val);
 206 }
 207
 208 static const struct sysfs_ops ttm_pool_sysfs_ops = {
 209         .show = &ttm_pool_show,
 210         .store = &ttm_pool_store,
 211 };
 212
 213 static struct kobj_type ttm_pool_kobj_type = {
 214         .release = &ttm_pool_kobj_release,
 215         .sysfs_ops = &ttm_pool_sysfs_ops,
 216         .default_attrs = ttm_pool_attrs,
 217 };
 218
 219 static struct ttm_pool_manager *_manager;
 220
 221 #ifndef CONFIG_X86
 222 static int set_pages_array_wb(struct page **pages, int addrinarray)
 223 {
 224 #ifdef TTM_HAS_AGP
 225         int i;
 226
 227         for (i = 0; i < addrinarray; i++)
 228                 unmap_page_from_agp(pages[i]);
 229 #endif
 230         return 0;
 231 }
 232
 233 static int set_pages_array_wc(struct page **pages, int addrinarray)
 234 {
 235 #ifdef TTM_HAS_AGP
 236         int i;
 237
 238         for (i = 0; i < addrinarray; i++)
 239                 map_page_into_agp(pages[i]);
 240 #endif
 241         return 0;
 242 }
 243
 244 static int set_pages_array_uc(struct page **pages, int addrinarray)
 245 {
 246 #ifdef TTM_HAS_AGP
 247         int i;
 248
 249         for (i = 0; i < addrinarray; i++)
 250                 map_page_into_agp(pages[i]);
 251 #endif
 252         return 0;
 253 }
 254 #endif
 255
 256 /**
 257  * Select the right pool or requested caching state and ttm flags. */
 258 static struct ttm_page_pool *ttm_get_pool(int flags,
 259                 enum ttm_caching_state cstate)
 260 {
 261         int pool_index;
 262
 263         if (cstate == tt_cached)
 264                 return NULL;
 265
 266         if (cstate == tt_wc)
 267                 pool_index = 0x0;
 268         else
 269                 pool_index = 0x1;
 270
 271         if (flags & TTM_PAGE_FLAG_DMA32)
 272                 pool_index |= 0x2;
 273
 274         return &_manager->pools[pool_index];
 275 }
 276
 277 /* set memory back to wb and free the pages. */
 278 static void ttm_pages_put(struct page *pages[], unsigned npages)
 279 {
 280         unsigned i;
 281         if (set_pages_array_wb(pages, npages))
 282                 printk(KERN_ERR TTM_PFX "Failed to set %d pages to wb!\n",
 283                                 npages);
 284         for (i = 0; i < npages; ++i)
 285                 __free_page(pages[i]);
 286 }
 287
 288 static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
 289                 unsigned freed_pages)
 290 {
 291         pool->npages -= freed_pages;
 292         pool->nfrees += freed_pages;
 293 }
 294
 295 /**
 296  * Free pages from pool.
 297  *
 298  * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
 299  * number of pages in one go.
 300  *
 301  * @pool: to free the pages from
 302  * @free_all: If set to true will free all pages in pool
 303  **/
 304 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
 305 {
 306         unsigned long irq_flags;
 307         struct page *p;
 308         struct page **pages_to_free;
 309         unsigned freed_pages = 0,
 310                  npages_to_free = nr_free;
 311
 312         if (NUM_PAGES_TO_ALLOC < nr_free)
 313                 npages_to_free = NUM_PAGES_TO_ALLOC;
 314
 315         pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
 316                         GFP_KERNEL);
 317         if (!pages_to_free) {
 318                 printk(KERN_ERR TTM_PFX
 319                        "Failed to allocate memory for pool free operation.\n");
 320                 return 0;
 321         }
 322
 323 restart:
 324         spin_lock_irqsave(&pool->lock, irq_flags);
 325
 326         list_for_each_entry_reverse(p, &pool->list, lru) {
 327                 if (freed_pages >= npages_to_free)
 328                         break;
 329
 330                 pages_to_free[freed_pages++] = p;
 331                 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
 332                 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
 333                         /* remove range of pages from the pool */
 334                         __list_del(p->lru.prev, &pool->list);
 335
 336                         ttm_pool_update_free_locked(pool, freed_pages);
 337                         /**
 338                          * Because changing page caching is costly
 339                          * we unlock the pool to prevent stalling.
 340                          */
 341                         spin_unlock_irqrestore(&pool->lock, irq_flags);
 342
 343                         ttm_pages_put(pages_to_free, freed_pages);
 344                         if (likely(nr_free != FREE_ALL_PAGES))
 345                                 nr_free -= freed_pages;
 346
 347                         if (NUM_PAGES_TO_ALLOC >= nr_free)
 348                                 npages_to_free = nr_free;
 349                         else
 350                                 npages_to_free = NUM_PAGES_TO_ALLOC;
 351
 352                         freed_pages = 0;
 353
 354                         /* free all so restart the processing */
 355                         if (nr_free)
 356                                 goto restart;
 357
 358                         /* Not allowed to fall through or break because
 359                          * following context is inside spinlock while we are
 360                          * outside here.
 361                          */
 362                         goto out;
 363
 364                 }
 365         }
 366
 367         /* remove range of pages from the pool */
 368         if (freed_pages) {
 369                 __list_del(&p->lru, &pool->list);
 370
 371                 ttm_pool_update_free_locked(pool, freed_pages);
 372                 nr_free -= freed_pages;
 373         }
 374
 375         spin_unlock_irqrestore(&pool->lock, irq_flags);
 376
 377         if (freed_pages)
 378                 ttm_pages_put(pages_to_free, freed_pages);
 379 out:
 380         kfree(pages_to_free);
 381         return nr_free;
 382 }
 383
 384 /* Get good estimation how many pages are free in pools */
 385 static int ttm_pool_get_num_unused_pages(void)
 386 {
 387         unsigned i;
 388         int total = 0;
 389         for (i = 0; i < NUM_POOLS; ++i)
 390                 total += _manager->pools[i].npages;
 391
 392         return total;
 393 }
 394
 395 /**
 396  * Callback for mm to request pool to reduce number of page held.
 397  */
 398 static int ttm_pool_mm_shrink(struct shrinker *shrink,
 399                               struct shrink_control *sc)
 400 {
 401         static DEFINE_MUTEX(lock);
 402         static unsigned start_pool;
 403         unsigned i;
 404         unsigned pool_offset;
 405         struct ttm_page_pool *pool;
 406         int shrink_pages = sc->nr_to_scan;
 407
 408         if (shrink_pages == 0)
 409                 goto out;
 410         if (!mutex_trylock(&lock))
 411                 return -1;
 412         pool_offset = ++start_pool % NUM_POOLS;
 413         /* select start pool in round robin fashion */
 414         for (i = 0; i < NUM_POOLS; ++i) {
 415                 unsigned nr_free = shrink_pages;
 416                 if (shrink_pages == 0)
 417                         break;
 418                 pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
 419                 shrink_pages = ttm_page_pool_free(pool, nr_free);
 420         }
 421         mutex_unlock(&lock);
 422 out:
 423         /* return estimated number of unused pages in pool */
 424         return ttm_pool_get_num_unused_pages();
 425 }
 426
 427 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 428 {
 429         manager->mm_shrink.shrink = &ttm_pool_mm_shrink;
 430         manager->mm_shrink.seeks = 1;
 431         register_shrinker(&manager->mm_shrink);
 432 }
 433
 434 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 435 {
 436         unregister_shrinker(&manager->mm_shrink);
 437 }
 438
 439 static int ttm_set_pages_caching(struct page **pages,
 440                 enum ttm_caching_state cstate, unsigned cpages)
 441 {
 442         int r = 0;
 443         /* Set page caching */
 444         switch (cstate) {
 445         case tt_uncached:
 446                 r = set_pages_array_uc(pages, cpages);
 447                 if (r)
 448                         printk(KERN_ERR TTM_PFX
 449                                "Failed to set %d pages to uc!\n",
 450                                cpages);
 451                 break;
 452         case tt_wc:
 453                 r = set_pages_array_wc(pages, cpages);
 454                 if (r)
 455                         printk(KERN_ERR TTM_PFX
 456                                "Failed to set %d pages to wc!\n",
 457                                cpages);
 458                 break;
 459         default:
 460                 break;
 461         }
 462         return r;
 463 }
 464
 465 /**
 466  * Free pages the pages that failed to change the caching state. If there is
 467  * any pages that have changed their caching state already put them to the
 468  * pool.
 469  */
 470 static void ttm_handle_caching_state_failure(struct list_head *pages,
 471                 int ttm_flags, enum ttm_caching_state cstate,
 472                 struct page **failed_pages, unsigned cpages)
 473 {
 474         unsigned i;
 475         /* Failed pages have to be freed */
 476         for (i = 0; i < cpages; ++i) {
 477                 list_del(&failed_pages[i]->lru);
 478                 __free_page(failed_pages[i]);
 479         }
 480 }
 481
 482 /**
 483  * Allocate new pages with correct caching.
 484  *
 485  * This function is reentrant if caller updates count depending on number of
 486  * pages returned in pages array.
 487  */
 488 static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
 489                 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 490 {
 491         struct page **caching_array;
 492         struct page *p;
 493         int r = 0;
 494         unsigned i, cpages;
 495         unsigned max_cpages = min(count,
 496                         (unsigned)(PAGE_SIZE/sizeof(struct page *)));
 497
 498         /* allocate array for page caching change */
 499         caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
 500
 501         if (!caching_array) {
 502                 printk(KERN_ERR TTM_PFX
 503                        "Unable to allocate table for new pages.");
 504                 return -ENOMEM;
 505         }
 506
 507         for (i = 0, cpages = 0; i < count; ++i) {
 508                 p = alloc_page(gfp_flags);
 509
 510                 if (!p) {
 511                         printk(KERN_ERR TTM_PFX "Unable to get page %u.\n", i);
 512
 513                         /* store already allocated pages in the pool after
 514                          * setting the caching state */
 515                         if (cpages) {
 516                                 r = ttm_set_pages_caching(caching_array,
 517                                                           cstate, cpages);
 518                                 if (r)
 519                                         ttm_handle_caching_state_failure(pages,
 520                                                 ttm_flags, cstate,
 521                                                 caching_array, cpages);
 522                         }
 523                         r = -ENOMEM;
 524                         goto out;
 525                 }
 526
 527 #ifdef CONFIG_HIGHMEM
 528                 /* gfp flags of highmem page should never be dma32 so we
 529                  * we should be fine in such case
 530                  */
 531                 if (!PageHighMem(p))
 532 #endif
 533                 {
 534                         caching_array[cpages++] = p;
 535                         if (cpages == max_cpages) {
 536
 537                                 r = ttm_set_pages_caching(caching_array,
 538                                                 cstate, cpages);
 539                                 if (r) {
 540                                         ttm_handle_caching_state_failure(pages,
 541                                                 ttm_flags, cstate,
 542                                                 caching_array, cpages);
 543                                         goto out;
 544                                 }
 545                                 cpages = 0;
 546                         }
 547                 }
 548
 549                 list_add(&p->lru, pages);
 550         }
 551
 552         if (cpages) {
 553                 r = ttm_set_pages_caching(caching_array, cstate, cpages);
 554                 if (r)
 555                         ttm_handle_caching_state_failure(pages,
 556                                         ttm_flags, cstate,
 557                                         caching_array, cpages);
 558         }
 559 out:
 560         kfree(caching_array);
 561
 562         return r;
 563 }
 564
 565 /**
 566  * Fill the given pool if there aren't enough pages and the requested number of
 567  * pages is small.
 568  */
 569 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 570                 int ttm_flags, enum ttm_caching_state cstate, unsigned count,
 571                 unsigned long *irq_flags)
 572 {
 573         struct page *p;
 574         int r;
 575         unsigned cpages = 0;
 576         /**
 577          * Only allow one pool fill operation at a time.
 578          * If pool doesn't have enough pages for the allocation new pages are
 579          * allocated from outside of pool.
 580          */
 581         if (pool->fill_lock)
 582                 return;
 583
 584         pool->fill_lock = true;
 585
 586         /* If allocation request is small and there are not enough
 587          * pages in a pool we fill the pool up first. */
 588         if (count < _manager->options.small
 589                 && count > pool->npages) {
 590                 struct list_head new_pages;
 591                 unsigned alloc_size = _manager->options.alloc_size;
 592
 593                 /**
 594                  * Can't change page caching if in irqsave context. We have to
 595                  * drop the pool->lock.
 596                  */
 597                 spin_unlock_irqrestore(&pool->lock, *irq_flags);
 598
 599                 INIT_LIST_HEAD(&new_pages);
 600                 r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
 601                                 cstate, alloc_size);
 602                 spin_lock_irqsave(&pool->lock, *irq_flags);
 603
 604                 if (!r) {
 605                         list_splice(&new_pages, &pool->list);
 606                         ++pool->nrefills;
 607                         pool->npages += alloc_size;
 608                 } else {
 609                         printk(KERN_ERR TTM_PFX
 610                                "Failed to fill pool (%p).", pool);
 611                         /* If we have any pages left put them to the pool. */
 612                         list_for_each_entry(p, &new_pages, lru) {
 613                                 ++cpages;
 614                         }
 615                         list_splice(&new_pages, &pool->list);
 616                         pool->npages += cpages;
 617                 }
 618
 619         }
 620         pool->fill_lock = false;
 621 }
 622
 623 /**
 624  * Cut 'count' number of pages from the pool and put them on the return list.
 625  *
 626  * @return count of pages still required to fulfill the request.
 627  */
 628 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
 629                 struct list_head *pages, int ttm_flags,
 630                 enum ttm_caching_state cstate, unsigned count)
 631 {
 632         unsigned long irq_flags;
 633         struct list_head *p;
 634         unsigned i;
 635
 636         spin_lock_irqsave(&pool->lock, irq_flags);
 637         ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
 638
 639         if (count >= pool->npages) {
 640                 /* take all pages from the pool */
 641                 list_splice_init(&pool->list, pages);
 642                 count -= pool->npages;
 643                 pool->npages = 0;
 644                 goto out;
 645         }
 646         /* find the last pages to include for requested number of pages. Split
 647          * pool to begin and halve it to reduce search space. */
 648         if (count <= pool->npages/2) {
 649                 i = 0;
 650                 list_for_each(p, &pool->list) {
 651                         if (++i == count)
 652                                 break;
 653                 }
 654         } else {
 655                 i = pool->npages + 1;
 656                 list_for_each_prev(p, &pool->list) {
 657                         if (--i == count)
 658                                 break;
 659                 }
 660         }
 661         /* Cut 'count' number of pages from the pool */
 662         list_cut_position(pages, &pool->list, p);
 663         pool->npages -= count;
 664         count = 0;
 665 out:
 666         spin_unlock_irqrestore(&pool->lock, irq_flags);
 667         return count;
 668 }
 669
 670 /*
 671  * On success pages list will hold count number of correctly
 672  * cached pages.
 673  */
 674 int ttm_get_pages(struct list_head *pages, int flags,
 675                   enum ttm_caching_state cstate, unsigned count,
 676                   dma_addr_t *dma_address)
 677 {
 678         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 679         struct page *p = NULL;
 680         gfp_t gfp_flags = GFP_USER;
 681         int r;
 682
 683         /* set zero flag for page allocation if required */
 684         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 685                 gfp_flags |= __GFP_ZERO;
 686
 687         /* No pool for cached pages */
 688         if (pool == NULL) {
 689                 if (flags & TTM_PAGE_FLAG_DMA32)
 690                         gfp_flags |= GFP_DMA32;
 691                 else
 692                         gfp_flags |= GFP_HIGHUSER;
 693
 694                 for (r = 0; r < count; ++r) {
 695                         p = alloc_page(gfp_flags);
 696                         if (!p) {
 697
 698                                 printk(KERN_ERR TTM_PFX
 699                                        "Unable to allocate page.");
 700                                 return -ENOMEM;
 701                         }
 702
 703                         list_add(&p->lru, pages);
 704                 }
 705                 return 0;
 706         }
 707
 708
 709         /* combine zero flag to pool flags */
 710         gfp_flags |= pool->gfp_flags;
 711
 712         /* First we take pages from the pool */
 713         count = ttm_page_pool_get_pages(pool, pages, flags, cstate, count);
 714
 715         /* clear the pages coming from the pool if requested */
 716         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 717                 list_for_each_entry(p, pages, lru) {
 718                         if (PageHighMem(p))
 719                                 clear_highpage(p);
 720                         else
 721                                 clear_page(page_address(p));
 722                 }
 723         }
 724
 725         /* If pool didn't have enough pages allocate new one. */
 726         if (count > 0) {
 727                 /* ttm_alloc_new_pages doesn't reference pool so we can run
 728                  * multiple requests in parallel.
 729                  **/
 730                 r = ttm_alloc_new_pages(pages, gfp_flags, flags, cstate, count);
 731                 if (r) {
 732                         /* If there is any pages in the list put them back to
 733                          * the pool. */
 734                         printk(KERN_ERR TTM_PFX
 735                                "Failed to allocate extra pages "
 736                                "for large request.");
 737                         ttm_put_pages(pages, 0, flags, cstate, NULL);
 738                         return r;
 739                 }
 740         }
 741
 742
 743         return 0;
 744 }
 745
 746 /* Put all pages in pages list to correct pool to wait for reuse */
 747 void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
 748                    enum ttm_caching_state cstate, dma_addr_t *dma_address)
 749 {
 750         unsigned long irq_flags;
 751         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 752         struct page *p, *tmp;
 753
 754         if (pool == NULL) {
 755                 /* No pool for this memory type so free the pages */
 756
 757                 list_for_each_entry_safe(p, tmp, pages, lru) {
 758                         __free_page(p);
 759                 }
 760                 /* Make the pages list empty */
 761                 INIT_LIST_HEAD(pages);
 762                 return;
 763         }
 764         if (page_count == 0) {
 765                 list_for_each_entry_safe(p, tmp, pages, lru) {
 766                         ++page_count;
 767                 }
 768         }
 769
 770         spin_lock_irqsave(&pool->lock, irq_flags);
 771         list_splice_init(pages, &pool->list);
 772         pool->npages += page_count;
 773         /* Check that we don't go over the pool limit */
 774         page_count = 0;
 775         if (pool->npages > _manager->options.max_size) {
 776                 page_count = pool->npages - _manager->options.max_size;
 777                 /* free at least NUM_PAGES_TO_ALLOC number of pages
 778                  * to reduce calls to set_memory_wb */
 779                 if (page_count < NUM_PAGES_TO_ALLOC)
 780                         page_count = NUM_PAGES_TO_ALLOC;
 781         }
 782         spin_unlock_irqrestore(&pool->lock, irq_flags);
 783         if (page_count)
 784                 ttm_page_pool_free(pool, page_count);
 785 }
 786
 787 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
 788                 char *name)
 789 {
 790         spin_lock_init(&pool->lock);
 791         pool->fill_lock = false;
 792         INIT_LIST_HEAD(&pool->list);
 793         pool->npages = pool->nfrees = 0;
 794         pool->gfp_flags = flags;
 795         pool->name = name;
 796 }
 797
 798 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 799 {
 800         int ret;
 801
 802         WARN_ON(_manager);
 803
 804         printk(KERN_INFO TTM_PFX "Initializing pool allocator.\n");
 805
 806         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 807
 808         ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
 809
 810         ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
 811
 812         ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
 813                                   GFP_USER | GFP_DMA32, "wc dma");
 814
 815         ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
 816                                   GFP_USER | GFP_DMA32, "uc dma");
 817
 818         _manager->options.max_size = max_pages;
 819         _manager->options.small = SMALL_ALLOCATION;
 820         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 821
 822         ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 823                                    &glob->kobj, "pool");
 824         if (unlikely(ret != 0)) {
 825                 kobject_put(&_manager->kobj);
 826                 _manager = NULL;
 827                 return ret;
 828         }
 829
 830         ttm_pool_mm_shrink_init(_manager);
 831
 832         return 0;
 833 }
 834
 835 void ttm_page_alloc_fini(void)
 836 {
 837         int i;
 838
 839         printk(KERN_INFO TTM_PFX "Finalizing pool allocator.\n");
 840         ttm_pool_mm_shrink_fini(_manager);
 841
 842         for (i = 0; i < NUM_POOLS; ++i)
 843                 ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
 844
 845         kobject_put(&_manager->kobj);
 846         _manager = NULL;
 847 }
 848
 849 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
 850 {
 851         struct ttm_page_pool *p;
 852         unsigned i;
 853         char *h[] = {"pool", "refills", "pages freed", "size"};
 854         if (!_manager) {
 855                 seq_printf(m, "No pool allocator running.\n");
 856                 return 0;
 857         }
 858         seq_printf(m, "%6s %12s %13s %8s\n",
 859                         h[0], h[1], h[2], h[3]);
 860         for (i = 0; i < NUM_POOLS; ++i) {
 861                 p = &_manager->pools[i];
 862
 863                 seq_printf(m, "%6s %12ld %13ld %8d\n",
 864                                 p->name, p->nrefills,
 865                                 p->nfrees, p->npages);
 866         }
 867         return 0;
 868 }
 869 EXPORT_SYMBOL(ttm_page_alloc_debugfs);