sys/dev/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  * Copyright (c) 2013 The FreeBSD Foundation
  29  * All rights reserved.
  30  *
  31  * Portions of this software were developed by Konstantin Belousov
  32  * <kib@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
  33  *
  34  * $FreeBSD: head/sys/dev/drm2/ttm/ttm_page_alloc.c 247849 2013-03-05 16:15:34Z kib $
  35  */
  36
  37 /* simple list based uncached page pool
  38  * - Pool collects resently freed pages for reuse
  39  * - Use page->lru to keep a free list
  40  * - doesn't track currently in use pages
  41  */
  42
  43 #define pr_fmt(fmt) "[TTM] " fmt
  44
  45 #include <sys/eventhandler.h>
  46
  47 #include <drm/drmP.h>
  48 #include <drm/ttm/ttm_bo_driver.h>
  49 #include <drm/ttm/ttm_page_alloc.h>
  50
  51 #ifdef TTM_HAS_AGP
  52 #include <asm/agp.h>
  53 #endif
  54
  55 #define NUM_PAGES_TO_ALLOC              (PAGE_SIZE/sizeof(vm_page_t))
  56 #define SMALL_ALLOCATION                16
  57 #define FREE_ALL_PAGES                  (~0U)
  58 /* times are in msecs */
  59 #define PAGE_FREE_INTERVAL              1000
  60
  61 /**
  62  * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
  63  *
  64  * @lock: Protects the shared pool from concurrnet access. Must be used with
  65  * irqsave/irqrestore variants because pool allocator maybe called from
  66  * delayed work.
  67  * @fill_lock: Prevent concurrent calls to fill.
  68  * @list: Pool of free uc/wc pages for fast reuse.
  69  * @gfp_flags: Flags to pass for alloc_page.
  70  * @npages: Number of pages in pool.
  71  */
  72 struct ttm_page_pool {
  73         struct lock             lock;
  74         bool                    fill_lock;
  75         bool                    dma32;
  76         struct pglist           list;
  77         int                     ttm_page_alloc_flags;
  78         unsigned                npages;
  79         char                    *name;
  80         unsigned long           nfrees;
  81         unsigned long           nrefills;
  82 };
  83
  84 /**
  85  * Limits for the pool. They are handled without locks because only place where
  86  * they may change is in sysfs store. They won't have immediate effect anyway
  87  * so forcing serialization to access them is pointless.
  88  */
  89
  90 struct ttm_pool_opts {
  91         unsigned        alloc_size;
  92         unsigned        max_size;
  93         unsigned        small;
  94 };
  95
  96 #define NUM_POOLS 4
  97
  98 /**
  99  * struct ttm_pool_manager - Holds memory pools for fst allocation
 100  *
 101  * Manager is read only object for pool code so it doesn't need locking.
 102  *
 103  * @free_interval: minimum number of jiffies between freeing pages from pool.
 104  * @page_alloc_inited: reference counting for pool allocation.
 105  * @work: Work that is used to shrink the pool. Work is only run when there is
 106  * some pages to free.
 107  * @small_allocation: Limit in number of pages what is small allocation.
 108  *
 109  * @pools: All pool objects in use.
 110  **/
 111 struct ttm_pool_manager {
 112         unsigned int kobj_ref;
 113         eventhandler_tag lowmem_handler;
 114         struct ttm_pool_opts    options;
 115
 116         union {
 117                 struct ttm_page_pool    u_pools[NUM_POOLS];
 118                 struct _utag {
 119                         struct ttm_page_pool    u_wc_pool;
 120                         struct ttm_page_pool    u_uc_pool;
 121                         struct ttm_page_pool    u_wc_pool_dma32;
 122                         struct ttm_page_pool    u_uc_pool_dma32;
 123                 } _ut;
 124         } _u;
 125 };
 126
 127 #define pools _u.u_pools
 128 #define wc_pool _u._ut.u_wc_pool
 129 #define uc_pool _u._ut.u_uc_pool
 130 #define wc_pool_dma32 _u._ut.u_wc_pool_dma32
 131 #define uc_pool_dma32 _u._ut.u_uc_pool_dma32
 132
 133 static void
 134 ttm_vm_page_free(vm_page_t m)
 135 {
 136
 137         KASSERT(m->object == NULL, ("ttm page %p is owned", m));
 138         KASSERT(m->wire_count == 1, ("ttm lost wire %p", m));
 139         KASSERT((m->flags & PG_FICTITIOUS) != 0, ("ttm lost fictitious %p", m));
 140 #if 0
 141         KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("ttm got unmanaged %p", m));
 142         m->oflags |= VPO_UNMANAGED;
 143 #endif
 144         m->flags &= ~PG_FICTITIOUS;
 145         vm_page_busy_wait(m, FALSE, "ttmvpf");
 146         vm_page_wakeup(m);
 147         vm_page_free_contig(m, PAGE_SIZE);
 148         /*
 149         vm_page_unwire(m, 0);
 150         vm_page_free(m);
 151         */
 152 }
 153
 154 static vm_memattr_t
 155 ttm_caching_state_to_vm(enum ttm_caching_state cstate)
 156 {
 157
 158         switch (cstate) {
 159         case tt_uncached:
 160                 return (VM_MEMATTR_UNCACHEABLE);
 161         case tt_wc:
 162                 return (VM_MEMATTR_WRITE_COMBINING);
 163         case tt_cached:
 164                 return (VM_MEMATTR_WRITE_BACK);
 165         }
 166         panic("caching state %d\n", cstate);
 167 }
 168
 169 static void ttm_pool_kobj_release(struct ttm_pool_manager *m)
 170 {
 171         kfree(m);
 172 }
 173
 174 #if 0
 175 /* XXXKIB sysctl */
 176 static ssize_t ttm_pool_store(struct ttm_pool_manager *m,
 177                 struct attribute *attr, const char *buffer, size_t size)
 178 {
 179         int chars;
 180         unsigned val;
 181         chars = sscanf(buffer, "%u", &val);
 182         if (chars == 0)
 183                 return size;
 184
 185         /* Convert kb to number of pages */
 186         val = val / (PAGE_SIZE >> 10);
 187
 188         if (attr == &ttm_page_pool_max)
 189                 m->options.max_size = val;
 190         else if (attr == &ttm_page_pool_small)
 191                 m->options.small = val;
 192         else if (attr == &ttm_page_pool_alloc_size) {
 193                 if (val > NUM_PAGES_TO_ALLOC*8) {
 194                         pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
 195                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
 196                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 197                         return size;
 198                 } else if (val > NUM_PAGES_TO_ALLOC) {
 199                         pr_warn("Setting allocation size to larger than %lu is not recommended\n",
 200                                 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
 201                 }
 202                 m->options.alloc_size = val;
 203         }
 204
 205         return size;
 206 }
 207
 208 static ssize_t ttm_pool_show(struct ttm_pool_manager *m,
 209                 struct attribute *attr, char *buffer)
 210 {
 211         unsigned val = 0;
 212
 213         if (attr == &ttm_page_pool_max)
 214                 val = m->options.max_size;
 215         else if (attr == &ttm_page_pool_small)
 216                 val = m->options.small;
 217         else if (attr == &ttm_page_pool_alloc_size)
 218                 val = m->options.alloc_size;
 219
 220         val = val * (PAGE_SIZE >> 10);
 221
 222         return snprintf(buffer, PAGE_SIZE, "%u\n", val);
 223 }
 224 #endif
 225
 226 static struct ttm_pool_manager *_manager;
 227
 228 static int set_pages_array_wb(vm_page_t *pages, int addrinarray)
 229 {
 230         vm_page_t m;
 231         int i;
 232
 233         for (i = 0; i < addrinarray; i++) {
 234                 m = pages[i];
 235 #ifdef TTM_HAS_AGP
 236                 unmap_page_from_agp(m);
 237 #endif
 238                 pmap_page_set_memattr(m, VM_MEMATTR_WRITE_BACK);
 239         }
 240         return 0;
 241 }
 242
 243 static int set_pages_array_wc(vm_page_t *pages, int addrinarray)
 244 {
 245         vm_page_t m;
 246         int i;
 247
 248         for (i = 0; i < addrinarray; i++) {
 249                 m = pages[i];
 250 #ifdef TTM_HAS_AGP
 251                 map_page_into_agp(pages[i]);
 252 #endif
 253                 pmap_page_set_memattr(m, VM_MEMATTR_WRITE_COMBINING);
 254         }
 255         return 0;
 256 }
 257
 258 static int set_pages_array_uc(vm_page_t *pages, int addrinarray)
 259 {
 260         vm_page_t m;
 261         int i;
 262
 263         for (i = 0; i < addrinarray; i++) {
 264                 m = pages[i];
 265 #ifdef TTM_HAS_AGP
 266                 map_page_into_agp(pages[i]);
 267 #endif
 268                 pmap_page_set_memattr(m, VM_MEMATTR_UNCACHEABLE);
 269         }
 270         return 0;
 271 }
 272
 273 /**
 274  * Select the right pool or requested caching state and ttm flags. */
 275 static struct ttm_page_pool *ttm_get_pool(int flags,
 276                 enum ttm_caching_state cstate)
 277 {
 278         int pool_index;
 279
 280         if (cstate == tt_cached)
 281                 return NULL;
 282
 283         if (cstate == tt_wc)
 284                 pool_index = 0x0;
 285         else
 286                 pool_index = 0x1;
 287
 288         if (flags & TTM_PAGE_FLAG_DMA32)
 289                 pool_index |= 0x2;
 290
 291         return &_manager->pools[pool_index];
 292 }
 293
 294 /* set memory back to wb and free the pages. */
 295 static void ttm_pages_put(vm_page_t *pages, unsigned npages)
 296 {
 297         unsigned i;
 298
 299         /* Our VM handles vm memattr automatically on the page free. */
 300         if (set_pages_array_wb(pages, npages))
 301                 pr_err("Failed to set %d pages to wb!\n", npages);
 302         for (i = 0; i < npages; ++i)
 303                 ttm_vm_page_free(pages[i]);
 304 }
 305
 306 static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
 307                 unsigned freed_pages)
 308 {
 309         pool->npages -= freed_pages;
 310         pool->nfrees += freed_pages;
 311 }
 312
 313 /**
 314  * Free pages from pool.
 315  *
 316  * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
 317  * number of pages in one go.
 318  *
 319  * @pool: to free the pages from
 320  * @free_all: If set to true will free all pages in pool
 321  **/
 322 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
 323 {
 324         vm_page_t p, p1;
 325         vm_page_t *pages_to_free;
 326         unsigned freed_pages = 0,
 327                  npages_to_free = nr_free;
 328         unsigned i;
 329
 330         if (NUM_PAGES_TO_ALLOC < nr_free)
 331                 npages_to_free = NUM_PAGES_TO_ALLOC;
 332
 333         pages_to_free = kmalloc(npages_to_free * sizeof(vm_page_t),
 334             M_TEMP, M_WAITOK | M_ZERO);
 335
 336 restart:
 337         lockmgr(&pool->lock, LK_EXCLUSIVE);
 338
 339         TAILQ_FOREACH_REVERSE_MUTABLE(p, &pool->list, pglist, pageq, p1) {
 340                 if (freed_pages >= npages_to_free)
 341                         break;
 342
 343                 pages_to_free[freed_pages++] = p;
 344                 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
 345                 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
 346                         /* remove range of pages from the pool */
 347                         for (i = 0; i < freed_pages; i++)
 348                                 TAILQ_REMOVE(&pool->list, pages_to_free[i], pageq);
 349
 350                         ttm_pool_update_free_locked(pool, freed_pages);
 351                         /**
 352                          * Because changing page caching is costly
 353                          * we unlock the pool to prevent stalling.
 354                          */
 355                         lockmgr(&pool->lock, LK_RELEASE);
 356
 357                         ttm_pages_put(pages_to_free, freed_pages);
 358                         if (likely(nr_free != FREE_ALL_PAGES))
 359                                 nr_free -= freed_pages;
 360
 361                         if (NUM_PAGES_TO_ALLOC >= nr_free)
 362                                 npages_to_free = nr_free;
 363                         else
 364                                 npages_to_free = NUM_PAGES_TO_ALLOC;
 365
 366                         freed_pages = 0;
 367
 368                         /* free all so restart the processing */
 369                         if (nr_free)
 370                                 goto restart;
 371
 372                         /* Not allowed to fall through or break because
 373                          * following context is inside spinlock while we are
 374                          * outside here.
 375                          */
 376                         goto out;
 377
 378                 }
 379         }
 380
 381         /* remove range of pages from the pool */
 382         if (freed_pages) {
 383                 for (i = 0; i < freed_pages; i++)
 384                         TAILQ_REMOVE(&pool->list, pages_to_free[i], pageq);
 385
 386                 ttm_pool_update_free_locked(pool, freed_pages);
 387                 nr_free -= freed_pages;
 388         }
 389
 390         lockmgr(&pool->lock, LK_RELEASE);
 391
 392         if (freed_pages)
 393                 ttm_pages_put(pages_to_free, freed_pages);
 394 out:
 395         drm_free(pages_to_free, M_TEMP);
 396         return nr_free;
 397 }
 398
 399 /* Get good estimation how many pages are free in pools */
 400 static int ttm_pool_get_num_unused_pages(void)
 401 {
 402         unsigned i;
 403         int total = 0;
 404         for (i = 0; i < NUM_POOLS; ++i)
 405                 total += _manager->pools[i].npages;
 406
 407         return total;
 408 }
 409
 410 /**
 411  * Callback for mm to request pool to reduce number of page held.
 412  */
 413 static int ttm_pool_mm_shrink(void *arg)
 414 {
 415         static unsigned int start_pool = 0;
 416         unsigned i;
 417         unsigned pool_offset = atomic_fetchadd_int(&start_pool, 1);
 418         struct ttm_page_pool *pool;
 419         int shrink_pages = 100; /* XXXKIB */
 420
 421         pool_offset = pool_offset % NUM_POOLS;
 422         /* select start pool in round robin fashion */
 423         for (i = 0; i < NUM_POOLS; ++i) {
 424                 unsigned nr_free = shrink_pages;
 425                 if (shrink_pages == 0)
 426                         break;
 427                 pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
 428                 shrink_pages = ttm_page_pool_free(pool, nr_free);
 429         }
 430         /* return estimated number of unused pages in pool */
 431         return ttm_pool_get_num_unused_pages();
 432 }
 433
 434 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 435 {
 436
 437         manager->lowmem_handler = EVENTHANDLER_REGISTER(vm_lowmem,
 438             ttm_pool_mm_shrink, manager, EVENTHANDLER_PRI_ANY);
 439 }
 440
 441 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 442 {
 443
 444         EVENTHANDLER_DEREGISTER(vm_lowmem, manager->lowmem_handler);
 445 }
 446
 447 static int ttm_set_pages_caching(vm_page_t *pages,
 448                 enum ttm_caching_state cstate, unsigned cpages)
 449 {
 450         int r = 0;
 451         /* Set page caching */
 452         switch (cstate) {
 453         case tt_uncached:
 454                 r = set_pages_array_uc(pages, cpages);
 455                 if (r)
 456                         pr_err("Failed to set %d pages to uc!\n", cpages);
 457                 break;
 458         case tt_wc:
 459                 r = set_pages_array_wc(pages, cpages);
 460                 if (r)
 461                         pr_err("Failed to set %d pages to wc!\n", cpages);
 462                 break;
 463         default:
 464                 break;
 465         }
 466         return r;
 467 }
 468
 469 /**
 470  * Free pages the pages that failed to change the caching state. If there is
 471  * any pages that have changed their caching state already put them to the
 472  * pool.
 473  */
 474 static void ttm_handle_caching_state_failure(struct pglist *pages,
 475                 int ttm_flags, enum ttm_caching_state cstate,
 476                 vm_page_t *failed_pages, unsigned cpages)
 477 {
 478         unsigned i;
 479         /* Failed pages have to be freed */
 480         for (i = 0; i < cpages; ++i) {
 481                 TAILQ_REMOVE(pages, failed_pages[i], pageq);
 482                 ttm_vm_page_free(failed_pages[i]);
 483         }
 484 }
 485
 486 /**
 487  * Allocate new pages with correct caching.
 488  *
 489  * This function is reentrant if caller updates count depending on number of
 490  * pages returned in pages array.
 491  */
 492 static int ttm_alloc_new_pages(struct pglist *pages, int ttm_alloc_flags,
 493                 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 494 {
 495         vm_page_t *caching_array;
 496         vm_page_t p;
 497         int r = 0;
 498         unsigned i, cpages, aflags;
 499         unsigned max_cpages = min(count,
 500                         (unsigned)(PAGE_SIZE/sizeof(vm_page_t)));
 501
 502         aflags = VM_ALLOC_NORMAL |
 503             ((ttm_alloc_flags & TTM_PAGE_FLAG_ZERO_ALLOC) != 0 ?
 504             VM_ALLOC_ZERO : 0);
 505
 506         /* allocate array for page caching change */
 507         caching_array = kmalloc(max_cpages * sizeof(vm_page_t), M_TEMP,
 508             M_WAITOK | M_ZERO);
 509
 510         for (i = 0, cpages = 0; i < count; ++i) {
 511                 p = vm_page_alloc_contig(0,
 512                     (ttm_alloc_flags & TTM_PAGE_FLAG_DMA32) ? 0xffffffff :
 513                     VM_MAX_ADDRESS, PAGE_SIZE, 0,
 514                     1*PAGE_SIZE, ttm_caching_state_to_vm(cstate));
 515                 if (!p) {
 516                         pr_err("Unable to get page %u\n", i);
 517
 518                         /* store already allocated pages in the pool after
 519                          * setting the caching state */
 520                         if (cpages) {
 521                                 r = ttm_set_pages_caching(caching_array,
 522                                                           cstate, cpages);
 523                                 if (r)
 524                                         ttm_handle_caching_state_failure(pages,
 525                                                 ttm_flags, cstate,
 526                                                 caching_array, cpages);
 527                         }
 528                         r = -ENOMEM;
 529                         goto out;
 530                 }
 531 #if 0
 532                 p->oflags &= ~VPO_UNMANAGED;
 533 #endif
 534                 p->flags |= PG_FICTITIOUS;
 535
 536 #ifdef CONFIG_HIGHMEM /* KIB: nop */
 537                 /* gfp flags of highmem page should never be dma32 so we
 538                  * we should be fine in such case
 539                  */
 540                 if (!PageHighMem(p))
 541 #endif
 542                 {
 543                         caching_array[cpages++] = p;
 544                         if (cpages == max_cpages) {
 545
 546                                 r = ttm_set_pages_caching(caching_array,
 547                                                 cstate, cpages);
 548                                 if (r) {
 549                                         ttm_handle_caching_state_failure(pages,
 550                                                 ttm_flags, cstate,
 551                                                 caching_array, cpages);
 552                                         goto out;
 553                                 }
 554                                 cpages = 0;
 555                         }
 556                 }
 557
 558                 TAILQ_INSERT_HEAD(pages, p, pageq);
 559         }
 560
 561         if (cpages) {
 562                 r = ttm_set_pages_caching(caching_array, cstate, cpages);
 563                 if (r)
 564                         ttm_handle_caching_state_failure(pages,
 565                                         ttm_flags, cstate,
 566                                         caching_array, cpages);
 567         }
 568 out:
 569         drm_free(caching_array, M_TEMP);
 570
 571         return r;
 572 }
 573
 574 /**
 575  * Fill the given pool if there aren't enough pages and the requested number of
 576  * pages is small.
 577  */
 578 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
 579     int ttm_flags, enum ttm_caching_state cstate, unsigned count)
 580 {
 581         vm_page_t p;
 582         int r;
 583         unsigned cpages = 0;
 584         /**
 585          * Only allow one pool fill operation at a time.
 586          * If pool doesn't have enough pages for the allocation new pages are
 587          * allocated from outside of pool.
 588          */
 589         if (pool->fill_lock)
 590                 return;
 591
 592         pool->fill_lock = true;
 593
 594         /* If allocation request is small and there are not enough
 595          * pages in a pool we fill the pool up first. */
 596         if (count < _manager->options.small
 597                 && count > pool->npages) {
 598                 struct pglist new_pages;
 599                 unsigned alloc_size = _manager->options.alloc_size;
 600
 601                 /**
 602                  * Can't change page caching if in irqsave context. We have to
 603                  * drop the pool->lock.
 604                  */
 605                 lockmgr(&pool->lock, LK_RELEASE);
 606
 607                 TAILQ_INIT(&new_pages);
 608                 r = ttm_alloc_new_pages(&new_pages, pool->ttm_page_alloc_flags,
 609                     ttm_flags, cstate, alloc_size);
 610                 lockmgr(&pool->lock, LK_EXCLUSIVE);
 611
 612                 if (!r) {
 613                         TAILQ_CONCAT(&pool->list, &new_pages, pageq);
 614                         ++pool->nrefills;
 615                         pool->npages += alloc_size;
 616                 } else {
 617                         pr_err("Failed to fill pool (%p)\n", pool);
 618                         /* If we have any pages left put them to the pool. */
 619                         TAILQ_FOREACH(p, &pool->list, pageq) {
 620                                 ++cpages;
 621                         }
 622                         TAILQ_CONCAT(&pool->list, &new_pages, pageq);
 623                         pool->npages += cpages;
 624                 }
 625
 626         }
 627         pool->fill_lock = false;
 628 }
 629
 630 /**
 631  * Cut 'count' number of pages from the pool and put them on the return list.
 632  *
 633  * @return count of pages still required to fulfill the request.
 634  */
 635 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
 636                                         struct pglist *pages,
 637                                         int ttm_flags,
 638                                         enum ttm_caching_state cstate,
 639                                         unsigned count)
 640 {
 641         vm_page_t p;
 642         unsigned i;
 643
 644         lockmgr(&pool->lock, LK_EXCLUSIVE);
 645         ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count);
 646
 647         if (count >= pool->npages) {
 648                 /* take all pages from the pool */
 649                 TAILQ_CONCAT(pages, &pool->list, pageq);
 650                 count -= pool->npages;
 651                 pool->npages = 0;
 652                 goto out;
 653         }
 654         for (i = 0; i < count; i++) {
 655                 p = TAILQ_FIRST(&pool->list);
 656                 TAILQ_REMOVE(&pool->list, p, pageq);
 657                 TAILQ_INSERT_TAIL(pages, p, pageq);
 658         }
 659         pool->npages -= count;
 660         count = 0;
 661 out:
 662         lockmgr(&pool->lock, LK_RELEASE);
 663         return count;
 664 }
 665
 666 /* Put all pages in pages list to correct pool to wait for reuse */
 667 static void ttm_put_pages(vm_page_t *pages, unsigned npages, int flags,
 668                           enum ttm_caching_state cstate)
 669 {
 670         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 671         unsigned i;
 672
 673         if (pool == NULL) {
 674                 /* No pool for this memory type so free the pages */
 675                 for (i = 0; i < npages; i++) {
 676                         if (pages[i]) {
 677                                 ttm_vm_page_free(pages[i]);
 678                                 pages[i] = NULL;
 679                         }
 680                 }
 681                 return;
 682         }
 683
 684         lockmgr(&pool->lock, LK_EXCLUSIVE);
 685         for (i = 0; i < npages; i++) {
 686                 if (pages[i]) {
 687                         TAILQ_INSERT_TAIL(&pool->list, pages[i], pageq);
 688                         pages[i] = NULL;
 689                         pool->npages++;
 690                 }
 691         }
 692         /* Check that we don't go over the pool limit */
 693         npages = 0;
 694         if (pool->npages > _manager->options.max_size) {
 695                 npages = pool->npages - _manager->options.max_size;
 696                 /* free at least NUM_PAGES_TO_ALLOC number of pages
 697                  * to reduce calls to set_memory_wb */
 698                 if (npages < NUM_PAGES_TO_ALLOC)
 699                         npages = NUM_PAGES_TO_ALLOC;
 700         }
 701         lockmgr(&pool->lock, LK_RELEASE);
 702         if (npages)
 703                 ttm_page_pool_free(pool, npages);
 704 }
 705
 706 /*
 707  * On success pages list will hold count number of correctly
 708  * cached pages.
 709  */
 710 static int ttm_get_pages(vm_page_t *pages, unsigned npages, int flags,
 711                          enum ttm_caching_state cstate)
 712 {
 713         struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
 714         struct pglist plist;
 715         vm_page_t p = NULL;
 716         int gfp_flags, aflags;
 717         unsigned count;
 718         int r;
 719
 720         aflags = VM_ALLOC_NORMAL |
 721             ((flags & TTM_PAGE_FLAG_ZERO_ALLOC) != 0 ? VM_ALLOC_ZERO : 0);
 722
 723         /* No pool for cached pages */
 724         if (pool == NULL) {
 725                 for (r = 0; r < npages; ++r) {
 726                         p = vm_page_alloc_contig(0,
 727                             (flags & TTM_PAGE_FLAG_DMA32) ? 0xffffffff :
 728                             VM_MAX_ADDRESS, PAGE_SIZE,
 729                             0, 1*PAGE_SIZE, ttm_caching_state_to_vm(cstate));
 730                         if (!p) {
 731                                 pr_err("Unable to allocate page\n");
 732                                 return -ENOMEM;
 733                         }
 734 #if 0
 735                         p->oflags &= ~VPO_UNMANAGED;
 736 #endif
 737                         p->flags |= PG_FICTITIOUS;
 738                         pages[r] = p;
 739                 }
 740                 return 0;
 741         }
 742
 743         /* combine zero flag to pool flags */
 744         gfp_flags = flags | pool->ttm_page_alloc_flags;
 745
 746         /* First we take pages from the pool */
 747         TAILQ_INIT(&plist);
 748         npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
 749         count = 0;
 750         TAILQ_FOREACH(p, &plist, pageq) {
 751                 pages[count++] = p;
 752         }
 753
 754         /* clear the pages coming from the pool if requested */
 755         if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 756                 TAILQ_FOREACH(p, &plist, pageq) {
 757                         pmap_zero_page(VM_PAGE_TO_PHYS(p));
 758                 }
 759         }
 760
 761         /* If pool didn't have enough pages allocate new one. */
 762         if (npages > 0) {
 763                 /* ttm_alloc_new_pages doesn't reference pool so we can run
 764                  * multiple requests in parallel.
 765                  **/
 766                 TAILQ_INIT(&plist);
 767                 r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate,
 768                     npages);
 769                 TAILQ_FOREACH(p, &plist, pageq) {
 770                         pages[count++] = p;
 771                 }
 772                 if (r) {
 773                         /* If there is any pages in the list put them back to
 774                          * the pool. */
 775                         pr_err("Failed to allocate extra pages for large request\n");
 776                         ttm_put_pages(pages, count, flags, cstate);
 777                         return r;
 778                 }
 779         }
 780
 781         return 0;
 782 }
 783
 784 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
 785                                       char *name)
 786 {
 787         lockinit(&pool->lock, "ttmpool", 0, LK_CANRECURSE);
 788         pool->fill_lock = false;
 789         TAILQ_INIT(&pool->list);
 790         pool->npages = pool->nfrees = 0;
 791         pool->ttm_page_alloc_flags = flags;
 792         pool->name = name;
 793 }
 794
 795 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 796 {
 797         WARN_ON(_manager);
 798
 799         pr_info("Initializing pool allocator\n");
 800
 801         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 802
 803         ttm_page_pool_init_locked(&_manager->wc_pool, 0, "wc");
 804         ttm_page_pool_init_locked(&_manager->uc_pool, 0, "uc");
 805         ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
 806             TTM_PAGE_FLAG_DMA32, "wc dma");
 807         ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
 808             TTM_PAGE_FLAG_DMA32, "uc dma");
 809
 810         _manager->options.max_size = max_pages;
 811         _manager->options.small = SMALL_ALLOCATION;
 812         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 813
 814         refcount_init(&_manager->kobj_ref, 1);
 815         ttm_pool_mm_shrink_init(_manager);
 816
 817         return 0;
 818 }
 819
 820 void ttm_page_alloc_fini(void)
 821 {
 822         int i;
 823
 824         pr_info("Finalizing pool allocator\n");
 825         ttm_pool_mm_shrink_fini(_manager);
 826
 827         for (i = 0; i < NUM_POOLS; ++i)
 828                 ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
 829
 830         if (refcount_release(&_manager->kobj_ref))
 831                 ttm_pool_kobj_release(_manager);
 832         _manager = NULL;
 833 }
 834
 835 int ttm_pool_populate(struct ttm_tt *ttm)
 836 {
 837         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 838         unsigned i;
 839         int ret;
 840
 841         if (ttm->state != tt_unpopulated)
 842                 return 0;
 843
 844         for (i = 0; i < ttm->num_pages; ++i) {
 845                 ret = ttm_get_pages(&ttm->pages[i], 1,
 846                                     ttm->page_flags,
 847                                     ttm->caching_state);
 848                 if (ret != 0) {
 849                         ttm_pool_unpopulate(ttm);
 850                         return -ENOMEM;
 851                 }
 852
 853                 ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
 854                                                 false, false);
 855                 if (unlikely(ret != 0)) {
 856                         ttm_pool_unpopulate(ttm);
 857                         return -ENOMEM;
 858                 }
 859         }
 860
 861         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 862                 ret = ttm_tt_swapin(ttm);
 863                 if (unlikely(ret != 0)) {
 864                         ttm_pool_unpopulate(ttm);
 865                         return ret;
 866                 }
 867         }
 868
 869         ttm->state = tt_unbound;
 870         return 0;
 871 }
 872
 873 void ttm_pool_unpopulate(struct ttm_tt *ttm)
 874 {
 875         unsigned i;
 876
 877         for (i = 0; i < ttm->num_pages; ++i) {
 878                 if (ttm->pages[i]) {
 879                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 880                                                  ttm->pages[i]);
 881                         ttm_put_pages(&ttm->pages[i], 1,
 882                                       ttm->page_flags,
 883                                       ttm->caching_state);
 884                 }
 885         }
 886         ttm->state = tt_unpopulated;
 887 }
 888
 889 #if 0
 890 /* XXXKIB sysctl */
 891 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
 892 {
 893         struct ttm_page_pool *p;
 894         unsigned i;
 895         char *h[] = {"pool", "refills", "pages freed", "size"};
 896         if (!_manager) {
 897                 seq_printf(m, "No pool allocator running.\n");
 898                 return 0;
 899         }
 900         seq_printf(m, "%6s %12s %13s %8s\n",
 901                         h[0], h[1], h[2], h[3]);
 902         for (i = 0; i < NUM_POOLS; ++i) {
 903                 p = &_manager->pools[i];
 904
 905                 seq_printf(m, "%6s %12ld %13ld %8d\n",
 906                                 p->name, p->nrefills,
 907                                 p->nfrees, p->npages);
 908         }
 909         return 0;
 910 }
 911 #endif