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 atomic_t start_pool = ATOMIC_INIT(0);
 402         unsigned i;
 403         unsigned pool_offset = atomic_add_return(1, &start_pool);
 404         struct ttm_page_pool *pool;
 405         int shrink_pages = sc->nr_to_scan;
 406
 407         pool_offset = pool_offset % NUM_POOLS;
 408         /* select start pool in round robin fashion */
 409         for (i = 0; i < NUM_POOLS; ++i) {
 410                 unsigned nr_free = shrink_pages;
 411                 if (shrink_pages == 0)
 412                         break;
 413                 pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
 414                 shrink_pages = ttm_page_pool_free(pool, nr_free);
 415         }
 416         /* return estimated number of unused pages in pool */
 417         return ttm_pool_get_num_unused_pages();
 418 }
 419
 420 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 421 {
 422         manager->mm_shrink.shrink = &ttm_pool_mm_shrink;
 423         manager->mm_shrink.seeks = 1;
 424         register_shrinker(&manager->mm_shrink);
 425 }
 426
 427 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 428 {
 429         unregister_shrinker(&manager->mm_shrink);
 430 }
 431
 432 static int ttm_set_pages_caching(struct page **pages,
 433                 enum ttm_caching_state cstate, unsigned cpages)
 434 {
 435         int r = 0;
 436         /* Set page caching */
 437         switch (cstate) {
 438         case tt_uncached:
 439                 r = set_pages_array_uc(pages, cpages);
 440                 if (r)
 441                         printk(KERN_ERR TTM_PFX
 442                                "Failed to set %d pages to uc!\n",
 443                                cpages);
 444                 break;
 445         case tt_wc:
 446                 r = set_pages_array_wc(pages, cpages);
 447                 if (r)
 448                         printk(KERN_ERR TTM_PFX
 449                                "Failed to set %d pages to wc!\n",
 450                                cpages);
 451                 break;
 452         default:
 453                 break;
 454         }
 455         return r;
 456 }
 457
 458 /**
 459  * Free pages the pages that failed to change the caching state. If there is
 460  * any pages that have changed their caching state already put them to the
 461  * pool.
 462  */
 463 static void ttm_handle_caching_state_failure(struct list_head *pages,
 464                 int ttm_flags, enum ttm_caching_state cstate,
 465                 struct page **failed_pages, unsigned cpages)
 466 {
 467         unsigned i;
 468         /* Failed pages have to be freed */
 469         for (i = 0; i < cpages; ++i) {
 470                 list_del(&failed_pages[i]->lru);
 471                 __free_page(failed_pages[i]);
 472         }
 473 }
 474
 475 /**
 476  * Allocate new pages with correct caching.
 477  *
 478  * This function is reentrant if caller updates count depending on number of
 479  * pages returned in pages array.
 480  */
 481 static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
 482                 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 483 {
 484         struct page **caching_array;
 485         struct page *p;
 486         int r = 0;
 487         unsigned i, cpages;
 488         unsigned max_cpages = min(count,
 489                         (unsigned)(PAGE_SIZE/sizeof(struct page *)));
 490
 491         /* allocate array for page caching change */
 492         caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
 493
 494         if (!caching_array) {
 495                 printk(KERN_ERR TTM_PFX
 496                        "Unable to allocate table for new pages.");
 497                 return -ENOMEM;
 498         }
 499
 500         for (i = 0, cpages = 0; i < count; ++i) {
 501                 p = alloc_page(gfp_flags);
 502
 503 #ifdef CONFIG_XEN
 504                 if (p && (gfp_flags & __GFP_DMA32)) {
 505                         r = xen_limit_pages_to_max_mfn(p, 0, 32);
 506                         if (r) {
 507                                 __free_page(p);
 508                                 printk(KERN_ERR TTM_PFX
 509                                        "Cannot restrict page (%d).", r);
 510                                 p = NULL;
 511                         } else if (gfp_flags & __GFP_ZERO)
 512                                 clear_page(page_address(p));
 513                 }
 514 #endif
 515
 516                 if (!p) {
 517                         printk(KERN_ERR TTM_PFX "Unable to get page %u.\n", i);
 518
 519                         /* store already allocated pages in the pool after
 520                          * setting the caching state */
 521                         if (cpages) {
 522                                 r = ttm_set_pages_caching(caching_array,
 523                                                           cstate, cpages);
 524                                 if (r)
 525                                         ttm_handle_caching_state_failure(pages,
 526                                                 ttm_flags, cstate,
 527                                                 caching_array, cpages);
 528                         }
 529                         r = -ENOMEM;
 530                         goto out;
 531                 }
 532
 533 #ifdef CONFIG_HIGHMEM
 534                 /* gfp flags of highmem page should never be dma32 so we
 535                  * we should be fine in such case
 536                  */
 537                 if (!PageHighMem(p))
 538 #endif
 539                 {
 540                         caching_array[cpages++] = p;
 541                         if (cpages == max_cpages) {
 542
 543                                 r = ttm_set_pages_caching(caching_array,
 544                                                 cstate, cpages);
 545                                 if (r) {
 546                                         ttm_handle_caching_state_failure(pages,
 547                                                 ttm_flags, cstate,
 548                                                 caching_array, cpages);
 549                                         goto out;
 550                                 }
 551                                 cpages = 0;
 552                         }
 553                 }
 554
 555                 list_add(&p->lru, pages);
 556         }
 557
 558         if (cpages) {
 559                 r = ttm_set_pages_caching(caching_array, cstate, cpages);
 560                 if (r)
 561                         ttm_handle_caching_state_failure(pages,
 562                                         ttm_flags, cstate,
 563                                         caching_array, cpages);
 564         }
 565 out:
 566         kfree(caching_array);
 567
 568         return r;
 569 }
 570
 571 /**
 572  * Fill the given pool if there aren't enough pages and the requested number of
 573  * pages is small.
 574  */
 575 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 576                 int ttm_flags, enum ttm_caching_state cstate, unsigned count,
 577                 unsigned long *irq_flags)
 578 {
 579         struct page *p;
 580         int r;
 581         unsigned cpages = 0;
 582         /**
 583          * Only allow one pool fill operation at a time.
 584          * If pool doesn't have enough pages for the allocation new pages are
 585          * allocated from outside of pool.
 586          */
 587         if (pool->fill_lock)
 588                 return;
 589
 590         pool->fill_lock = true;
 591
 592         /* If allocation request is small and there are not enough
 593          * pages in a pool we fill the pool up first. */
 594         if (count < _manager->options.small
 595                 && count > pool->npages) {
 596                 struct list_head new_pages;
 597                 unsigned alloc_size = _manager->options.alloc_size;
 598
 599                 /**
 600                  * Can't change page caching if in irqsave context. We have to
 601                  * drop the pool->lock.
 602                  */
 603                 spin_unlock_irqrestore(&pool->lock, *irq_flags);
 604
 605                 INIT_LIST_HEAD(&new_pages);
 606                 r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
 607                                 cstate, alloc_size);
 608                 spin_lock_irqsave(&pool->lock, *irq_flags);
 609
 610                 if (!r) {
 611                         list_splice(&new_pages, &pool->list);
 612                         ++pool->nrefills;
 613                         pool->npages += alloc_size;
 614                 } else {
 615                         printk(KERN_ERR TTM_PFX
 616                                "Failed to fill pool (%p).", pool);
 617                         /* If we have any pages left put them to the pool. */
 618                         list_for_each_entry(p, &pool->list, lru) {
 619                                 ++cpages;
 620                         }
 621                         list_splice(&new_pages, &pool->list);
 622                         pool->npages += cpages;
 623                 }
 624
 625         }
 626         pool->fill_lock = false;
 627 }
 628
 629 /**
 630  * Cut 'count' number of pages from the pool and put them on the return list.
 631  *
 632  * @return count of pages still required to fulfill the request.
 633  */
 634 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
 635                                         struct list_head *pages,
 636                                         int ttm_flags,
 637                                         enum ttm_caching_state cstate,
 638                                         unsigned count)
 639 {
 640         unsigned long irq_flags;
 641         struct list_head *p;
 642         unsigned i;
 643
 644         spin_lock_irqsave(&pool->lock, irq_flags);
 645         ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
 646
 647         if (count >= pool->npages) {
 648                 /* take all pages from the pool */
 649                 list_splice_init(&pool->list, pages);
 650                 count -= pool->npages;
 651                 pool->npages = 0;
 652                 goto out;
 653         }
 654         /* find the last pages to include for requested number of pages. Split
 655          * pool to begin and halve it to reduce search space. */
 656         if (count <= pool->npages/2) {
 657                 i = 0;
 658                 list_for_each(p, &pool->list) {
 659                         if (++i == count)
 660                                 break;
 661                 }
 662         } else {
 663                 i = pool->npages + 1;
 664                 list_for_each_prev(p, &pool->list) {
 665                         if (--i == count)
 666                                 break;
 667                 }
 668         }
 669         /* Cut 'count' number of pages from the pool */
 670         list_cut_position(pages, &pool->list, p);
 671         pool->npages -= count;
 672         count = 0;
 673 out:
 674         spin_unlock_irqrestore(&pool->lock, irq_flags);
 675         return count;
 676 }
 677
 678 /* Put all pages in pages list to correct pool to wait for reuse */
 679 static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 680                           enum ttm_caching_state cstate)
 681 {
 682         unsigned long irq_flags;
 683         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 684         unsigned i;
 685
 686         if (pool == NULL) {
 687                 /* No pool for this memory type so free the pages */
 688                 for (i = 0; i < npages; i++) {
 689                         if (pages[i]) {
 690                                 if (page_count(pages[i]) != 1)
 691                                         printk(KERN_ERR TTM_PFX
 692                                                "Erroneous page count. "
 693                                                "Leaking pages.\n");
 694                                 __free_page(pages[i]);
 695                                 pages[i] = NULL;
 696                         }
 697                 }
 698                 return;
 699         }
 700
 701         spin_lock_irqsave(&pool->lock, irq_flags);
 702         for (i = 0; i < npages; i++) {
 703                 if (pages[i]) {
 704                         if (page_count(pages[i]) != 1)
 705                                 printk(KERN_ERR TTM_PFX
 706                                        "Erroneous page count. "
 707                                        "Leaking pages.\n");
 708                         list_add_tail(&pages[i]->lru, &pool->list);
 709                         pages[i] = NULL;
 710                         pool->npages++;
 711                 }
 712         }
 713         /* Check that we don't go over the pool limit */
 714         npages = 0;
 715         if (pool->npages > _manager->options.max_size) {
 716                 npages = pool->npages - _manager->options.max_size;
 717                 /* free at least NUM_PAGES_TO_ALLOC number of pages
 718                  * to reduce calls to set_memory_wb */
 719                 if (npages < NUM_PAGES_TO_ALLOC)
 720                         npages = NUM_PAGES_TO_ALLOC;
 721         }
 722         spin_unlock_irqrestore(&pool->lock, irq_flags);
 723         if (npages)
 724                 ttm_page_pool_free(pool, npages);
 725 }
 726
 727 /*
 728  * On success pages list will hold count number of correctly
 729  * cached pages.
 730  */
 731 static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 732                          enum ttm_caching_state cstate)
 733 {
 734         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 735         struct list_head plist;
 736         struct page *p = NULL;
 737         gfp_t gfp_flags = GFP_USER;
 738         unsigned count;
 739         int r;
 740
 741         /* set zero flag for page allocation if required */
 742         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 743                 gfp_flags |= __GFP_ZERO;
 744
 745         /* No pool for cached pages */
 746         if (pool == NULL) {
 747                 if (flags & TTM_PAGE_FLAG_DMA32)
 748                         gfp_flags |= GFP_DMA32;
 749                 else
 750                         gfp_flags |= GFP_HIGHUSER;
 751
 752                 for (r = 0; r < npages; ++r) {
 753                         p = alloc_page(gfp_flags);
 754                         if (!p) {
 755
 756                                 printk(KERN_ERR TTM_PFX
 757                                        "Unable to allocate page.");
 758                                 return -ENOMEM;
 759                         }
 760
 761 #ifdef CONFIG_XEN
 762                         if (flags & TTM_PAGE_FLAG_DMA32) {
 763                                 int rc = xen_limit_pages_to_max_mfn(p, 0, 32);
 764
 765                                 if (rc) {
 766                                         __free_page(p);
 767                                         printk(KERN_ERR TTM_PFX
 768                                                "Unable to restrict page (%d).",
 769                                                rc);
 770                                         return rc;
 771                                 }
 772                                 if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 773                                         clear_page(page_address(p));
 774                         }
 775 #endif
 776
 777                         pages[r] = p;
 778                 }
 779                 return 0;
 780         }
 781
 782         /* combine zero flag to pool flags */
 783         gfp_flags |= pool->gfp_flags;
 784
 785         /* First we take pages from the pool */
 786         INIT_LIST_HEAD(&plist);
 787         npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
 788         count = 0;
 789         list_for_each_entry(p, &plist, lru) {
 790                 pages[count++] = p;
 791         }
 792
 793         /* clear the pages coming from the pool if requested */
 794         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 795                 list_for_each_entry(p, &plist, lru) {
 796                         clear_page(page_address(p));
 797                 }
 798         }
 799
 800         /* If pool didn't have enough pages allocate new one. */
 801         if (npages > 0) {
 802                 /* ttm_alloc_new_pages doesn't reference pool so we can run
 803                  * multiple requests in parallel.
 804                  **/
 805                 INIT_LIST_HEAD(&plist);
 806                 r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate, npages);
 807                 list_for_each_entry(p, &plist, lru) {
 808                         pages[count++] = p;
 809                 }
 810                 if (r) {
 811                         /* If there is any pages in the list put them back to
 812                          * the pool. */
 813                         printk(KERN_ERR TTM_PFX
 814                                "Failed to allocate extra pages "
 815                                "for large request.");
 816                         ttm_put_pages(pages, count, flags, cstate);
 817                         return r;
 818                 }
 819         }
 820
 821         return 0;
 822 }
 823
 824 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
 825                 char *name)
 826 {
 827         spin_lock_init(&pool->lock);
 828         pool->fill_lock = false;
 829         INIT_LIST_HEAD(&pool->list);
 830         pool->npages = pool->nfrees = 0;
 831         pool->gfp_flags = flags;
 832         pool->name = name;
 833 }
 834
 835 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 836 {
 837         int ret;
 838
 839         WARN_ON(_manager);
 840
 841         printk(KERN_INFO TTM_PFX "Initializing pool allocator.\n");
 842
 843         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 844
 845         ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
 846
 847         ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
 848
 849         ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
 850                                   GFP_USER | GFP_DMA32, "wc dma");
 851
 852         ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
 853                                   GFP_USER | GFP_DMA32, "uc dma");
 854
 855         _manager->options.max_size = max_pages;
 856         _manager->options.small = SMALL_ALLOCATION;
 857         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 858
 859         ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 860                                    &glob->kobj, "pool");
 861         if (unlikely(ret != 0)) {
 862                 kobject_put(&_manager->kobj);
 863                 _manager = NULL;
 864                 return ret;
 865         }
 866
 867         ttm_pool_mm_shrink_init(_manager);
 868
 869         return 0;
 870 }
 871
 872 void ttm_page_alloc_fini(void)
 873 {
 874         int i;
 875
 876         printk(KERN_INFO TTM_PFX "Finalizing pool allocator.\n");
 877         ttm_pool_mm_shrink_fini(_manager);
 878
 879         for (i = 0; i < NUM_POOLS; ++i)
 880                 ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
 881
 882         kobject_put(&_manager->kobj);
 883         _manager = NULL;
 884 }
 885
 886 int ttm_pool_populate(struct ttm_tt *ttm)
 887 {
 888         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 889         unsigned i;
 890         int ret;
 891
 892         if (ttm->state != tt_unpopulated)
 893                 return 0;
 894
 895         for (i = 0; i < ttm->num_pages; ++i) {
 896                 ret = ttm_get_pages(&ttm->pages[i], 1,
 897                                     ttm->page_flags,
 898                                     ttm->caching_state);
 899                 if (ret != 0) {
 900                         ttm_pool_unpopulate(ttm);
 901                         return -ENOMEM;
 902                 }
 903
 904                 ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
 905                                                 false, false);
 906                 if (unlikely(ret != 0)) {
 907                         ttm_pool_unpopulate(ttm);
 908                         return -ENOMEM;
 909                 }
 910         }
 911
 912         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 913                 ret = ttm_tt_swapin(ttm);
 914                 if (unlikely(ret != 0)) {
 915                         ttm_pool_unpopulate(ttm);
 916                         return ret;
 917                 }
 918         }
 919
 920         ttm->state = tt_unbound;
 921         return 0;
 922 }
 923 EXPORT_SYMBOL(ttm_pool_populate);
 924
 925 void ttm_pool_unpopulate(struct ttm_tt *ttm)
 926 {
 927         unsigned i;
 928
 929         for (i = 0; i < ttm->num_pages; ++i) {
 930                 if (ttm->pages[i]) {
 931                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 932                                                  ttm->pages[i]);
 933                         ttm_put_pages(&ttm->pages[i], 1,
 934                                       ttm->page_flags,
 935                                       ttm->caching_state);
 936                 }
 937         }
 938         ttm->state = tt_unpopulated;
 939 }
 940 EXPORT_SYMBOL(ttm_pool_unpopulate);
 941
 942 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
 943 {
 944         struct ttm_page_pool *p;
 945         unsigned i;
 946         char *h[] = {"pool", "refills", "pages freed", "size"};
 947         if (!_manager) {
 948                 seq_printf(m, "No pool allocator running.\n");
 949                 return 0;
 950         }
 951         seq_printf(m, "%6s %12s %13s %8s\n",
 952                         h[0], h[1], h[2], h[3]);
 953         for (i = 0; i < NUM_POOLS; ++i) {
 954                 p = &_manager->pools[i];
 955
 956                 seq_printf(m, "%6s %12ld %13ld %8d\n",
 957                                 p->name, p->nrefills,
 958                                 p->nfrees, p->npages);
 959         }
 960         return 0;
 961 }
 962 EXPORT_SYMBOL(ttm_page_alloc_debugfs);