git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/btree_key_cache.c

   1
   2 #include "bcachefs.h"
   3 #include "btree_cache.h"
   4 #include "btree_iter.h"
   5 #include "btree_key_cache.h"
   6 #include "btree_locking.h"
   7 #include "btree_update.h"
   8 #include "error.h"
   9 #include "journal.h"
  10 #include "journal_reclaim.h"
  11
  12 #include <linux/sched/mm.h>
  13 #include <trace/events/bcachefs.h>
  14
  15 static struct kmem_cache *bch2_key_cache;
  16
  17 static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
  18                                        const void *obj)
  19 {
  20         const struct bkey_cached *ck = obj;
  21         const struct bkey_cached_key *key = arg->key;
  22
  23         return cmp_int(ck->key.btree_id, key->btree_id) ?:
  24                 bkey_cmp(ck->key.pos, key->pos);
  25 }
  26
  27 static const struct rhashtable_params bch2_btree_key_cache_params = {
  28         .head_offset    = offsetof(struct bkey_cached, hash),
  29         .key_offset     = offsetof(struct bkey_cached, key),
  30         .key_len        = sizeof(struct bkey_cached_key),
  31         .obj_cmpfn      = bch2_btree_key_cache_cmp_fn,
  32 };
  33
  34 __flatten
  35 inline struct bkey_cached *
  36 bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
  37 {
  38         struct bkey_cached_key key = {
  39                 .btree_id       = btree_id,
  40                 .pos            = pos,
  41         };
  42
  43         return rhashtable_lookup_fast(&c->btree_key_cache.table, &key,
  44                                       bch2_btree_key_cache_params);
  45 }
  46
  47 static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
  48 {
  49         if (!six_trylock_intent(&ck->c.lock))
  50                 return false;
  51
  52         if (!six_trylock_write(&ck->c.lock)) {
  53                 six_unlock_intent(&ck->c.lock);
  54                 return false;
  55         }
  56
  57         if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
  58                 six_unlock_write(&ck->c.lock);
  59                 six_unlock_intent(&ck->c.lock);
  60                 return false;
  61         }
  62
  63         return true;
  64 }
  65
  66 static void bkey_cached_evict(struct btree_key_cache *c,
  67                               struct bkey_cached *ck)
  68 {
  69         BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
  70                                       bch2_btree_key_cache_params));
  71         memset(&ck->key, ~0, sizeof(ck->key));
  72
  73         c->nr_keys--;
  74 }
  75
  76 static void bkey_cached_free(struct btree_key_cache *bc,
  77                              struct bkey_cached *ck)
  78 {
  79         struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
  80
  81         BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
  82
  83         ck->btree_trans_barrier_seq =
  84                 start_poll_synchronize_srcu(&c->btree_trans_barrier);
  85
  86         list_move_tail(&ck->list, &bc->freed);
  87         bc->nr_freed++;
  88
  89         kfree(ck->k);
  90         ck->k           = NULL;
  91         ck->u64s        = 0;
  92
  93         six_unlock_write(&ck->c.lock);
  94         six_unlock_intent(&ck->c.lock);
  95 }
  96
  97 static struct bkey_cached *
  98 bkey_cached_alloc(struct btree_key_cache *c)
  99 {
 100         struct bkey_cached *ck;
 101
 102         list_for_each_entry_reverse(ck, &c->freed, list)
 103                 if (bkey_cached_lock_for_evict(ck)) {
 104                         c->nr_freed--;
 105                         return ck;
 106                 }
 107
 108         ck = kmem_cache_alloc(bch2_key_cache, GFP_NOFS|__GFP_ZERO);
 109         if (likely(ck)) {
 110                 INIT_LIST_HEAD(&ck->list);
 111                 six_lock_init(&ck->c.lock);
 112                 BUG_ON(!six_trylock_intent(&ck->c.lock));
 113                 BUG_ON(!six_trylock_write(&ck->c.lock));
 114                 return ck;
 115         }
 116
 117         list_for_each_entry(ck, &c->clean, list)
 118                 if (bkey_cached_lock_for_evict(ck)) {
 119                         bkey_cached_evict(c, ck);
 120                         return ck;
 121                 }
 122
 123         return NULL;
 124 }
 125
 126 static struct bkey_cached *
 127 btree_key_cache_create(struct btree_key_cache *c,
 128                        enum btree_id btree_id,
 129                        struct bpos pos)
 130 {
 131         struct bkey_cached *ck;
 132
 133         ck = bkey_cached_alloc(c);
 134         if (!ck)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         ck->c.level             = 0;
 138         ck->c.btree_id          = btree_id;
 139         ck->key.btree_id        = btree_id;
 140         ck->key.pos             = pos;
 141         ck->valid               = false;
 142         ck->flags               = 1U << BKEY_CACHED_ACCESSED;
 143
 144         if (rhashtable_lookup_insert_fast(&c->table,
 145                                           &ck->hash,
 146                                           bch2_btree_key_cache_params)) {
 147                 /* We raced with another fill: */
 148                 bkey_cached_free(c, ck);
 149                 return NULL;
 150         }
 151
 152         c->nr_keys++;
 153
 154         list_move(&ck->list, &c->clean);
 155         six_unlock_write(&ck->c.lock);
 156
 157         return ck;
 158 }
 159
 160 static int btree_key_cache_fill(struct btree_trans *trans,
 161                                 struct btree_iter *ck_iter,
 162                                 struct bkey_cached *ck)
 163 {
 164         struct btree_iter *iter;
 165         struct bkey_s_c k;
 166         unsigned new_u64s = 0;
 167         struct bkey_i *new_k = NULL;
 168         int ret;
 169
 170         iter = bch2_trans_get_iter(trans, ck->key.btree_id,
 171                                    ck->key.pos, BTREE_ITER_SLOTS);
 172         k = bch2_btree_iter_peek_slot(iter);
 173         ret = bkey_err(k);
 174         if (ret)
 175                 goto err;
 176
 177         if (!bch2_btree_node_relock(ck_iter, 0)) {
 178                 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 179                 ret = -EINTR;
 180                 goto err;
 181         }
 182
 183         if (k.k->u64s > ck->u64s) {
 184                 new_u64s = roundup_pow_of_two(k.k->u64s);
 185                 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOFS);
 186                 if (!new_k) {
 187                         ret = -ENOMEM;
 188                         goto err;
 189                 }
 190         }
 191
 192         bch2_btree_node_lock_write(ck_iter->l[0].b, ck_iter);
 193         if (new_k) {
 194                 kfree(ck->k);
 195                 ck->u64s = new_u64s;
 196                 ck->k = new_k;
 197         }
 198
 199         bkey_reassemble(ck->k, k);
 200         ck->valid = true;
 201         bch2_btree_node_unlock_write(ck_iter->l[0].b, ck_iter);
 202
 203         /* We're not likely to need this iterator again: */
 204         set_btree_iter_dontneed(trans, iter);
 205 err:
 206         bch2_trans_iter_put(trans, iter);
 207         return ret;
 208 }
 209
 210 static int bkey_cached_check_fn(struct six_lock *lock, void *p)
 211 {
 212         struct bkey_cached *ck = container_of(lock, struct bkey_cached, c.lock);
 213         const struct btree_iter *iter = p;
 214
 215         return ck->key.btree_id == iter->btree_id &&
 216                 !bkey_cmp(ck->key.pos, iter->pos) ? 0 : -1;
 217 }
 218
 219 __flatten
 220 int bch2_btree_iter_traverse_cached(struct btree_iter *iter)
 221 {
 222         struct btree_trans *trans = iter->trans;
 223         struct bch_fs *c = trans->c;
 224         struct bkey_cached *ck;
 225         int ret = 0;
 226
 227         BUG_ON(iter->level);
 228
 229         if (btree_node_locked(iter, 0)) {
 230                 ck = (void *) iter->l[0].b;
 231                 goto fill;
 232         }
 233 retry:
 234         ck = bch2_btree_key_cache_find(c, iter->btree_id, iter->pos);
 235         if (!ck) {
 236                 if (iter->flags & BTREE_ITER_CACHED_NOCREATE) {
 237                         iter->l[0].b = NULL;
 238                         return 0;
 239                 }
 240
 241                 mutex_lock(&c->btree_key_cache.lock);
 242                 ck = btree_key_cache_create(&c->btree_key_cache,
 243                                             iter->btree_id, iter->pos);
 244                 mutex_unlock(&c->btree_key_cache.lock);
 245
 246                 ret = PTR_ERR_OR_ZERO(ck);
 247                 if (ret)
 248                         goto err;
 249                 if (!ck)
 250                         goto retry;
 251
 252                 mark_btree_node_locked(iter, 0, SIX_LOCK_intent);
 253                 iter->locks_want = 1;
 254         } else {
 255                 enum six_lock_type lock_want = __btree_lock_want(iter, 0);
 256
 257                 if (!btree_node_lock((void *) ck, iter->pos, 0, iter, lock_want,
 258                                      bkey_cached_check_fn, iter, _THIS_IP_)) {
 259                         if (ck->key.btree_id != iter->btree_id ||
 260                             bkey_cmp(ck->key.pos, iter->pos)) {
 261                                 goto retry;
 262                         }
 263
 264                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 265                         ret = -EINTR;
 266                         goto err;
 267                 }
 268
 269                 if (ck->key.btree_id != iter->btree_id ||
 270                     bkey_cmp(ck->key.pos, iter->pos)) {
 271                         six_unlock_type(&ck->c.lock, lock_want);
 272                         goto retry;
 273                 }
 274
 275                 mark_btree_node_locked(iter, 0, lock_want);
 276         }
 277
 278         iter->l[0].lock_seq     = ck->c.lock.state.seq;
 279         iter->l[0].b            = (void *) ck;
 280 fill:
 281         if (!ck->valid && !(iter->flags & BTREE_ITER_CACHED_NOFILL)) {
 282                 if (!btree_node_intent_locked(iter, 0))
 283                         bch2_btree_iter_upgrade(iter, 1);
 284                 if (!btree_node_intent_locked(iter, 0)) {
 285                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 286                         ret = -EINTR;
 287                         goto err;
 288                 }
 289
 290                 ret = btree_key_cache_fill(trans, iter, ck);
 291                 if (ret)
 292                         goto err;
 293         }
 294
 295         if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 296                 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 297
 298         iter->uptodate = BTREE_ITER_NEED_PEEK;
 299
 300         if (!(iter->flags & BTREE_ITER_INTENT))
 301                 bch2_btree_iter_downgrade(iter);
 302         else if (!iter->locks_want) {
 303                 if (!__bch2_btree_iter_upgrade(iter, 1))
 304                         ret = -EINTR;
 305         }
 306
 307         return ret;
 308 err:
 309         if (ret != -EINTR) {
 310                 btree_node_unlock(iter, 0);
 311                 iter->flags |= BTREE_ITER_ERROR;
 312                 iter->l[0].b = BTREE_ITER_NO_NODE_ERROR;
 313         }
 314         return ret;
 315 }
 316
 317 static int btree_key_cache_flush_pos(struct btree_trans *trans,
 318                                      struct bkey_cached_key key,
 319                                      u64 journal_seq,
 320                                      bool evict)
 321 {
 322         struct bch_fs *c = trans->c;
 323         struct journal *j = &c->journal;
 324         struct btree_iter *c_iter = NULL, *b_iter = NULL;
 325         struct bkey_cached *ck = NULL;
 326         int ret;
 327
 328         b_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 329                                      BTREE_ITER_SLOTS|
 330                                      BTREE_ITER_INTENT);
 331         c_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 332                                      BTREE_ITER_CACHED|
 333                                      BTREE_ITER_CACHED_NOFILL|
 334                                      BTREE_ITER_CACHED_NOCREATE|
 335                                      BTREE_ITER_INTENT);
 336 retry:
 337         ret = bch2_btree_iter_traverse(c_iter);
 338         if (ret)
 339                 goto err;
 340
 341         ck = (void *) c_iter->l[0].b;
 342         if (!ck ||
 343             (journal_seq && ck->journal.seq != journal_seq))
 344                 goto out;
 345
 346         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 347                 if (!evict)
 348                         goto out;
 349                 goto evict;
 350         }
 351
 352         ret   = bch2_btree_iter_traverse(b_iter) ?:
 353                 bch2_trans_update(trans, b_iter, ck->k, BTREE_TRIGGER_NORUN) ?:
 354                 bch2_trans_commit(trans, NULL, NULL,
 355                                   BTREE_INSERT_NOUNLOCK|
 356                                   BTREE_INSERT_NOCHECK_RW|
 357                                   BTREE_INSERT_NOFAIL|
 358                                   BTREE_INSERT_JOURNAL_RESERVED|
 359                                   BTREE_INSERT_JOURNAL_RECLAIM);
 360 err:
 361         if (ret == -EINTR)
 362                 goto retry;
 363
 364         if (ret) {
 365                 bch2_fs_fatal_err_on(!bch2_journal_error(j), c,
 366                         "error flushing key cache: %i", ret);
 367                 goto out;
 368         }
 369
 370         bch2_journal_pin_drop(j, &ck->journal);
 371         bch2_journal_preres_put(j, &ck->res);
 372
 373         if (!evict) {
 374                 mutex_lock(&c->btree_key_cache.lock);
 375                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 376                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 377                         c->btree_key_cache.nr_dirty--;
 378                 }
 379
 380                 list_move_tail(&ck->list, &c->btree_key_cache.clean);
 381                 mutex_unlock(&c->btree_key_cache.lock);
 382         } else {
 383 evict:
 384                 BUG_ON(!btree_node_intent_locked(c_iter, 0));
 385
 386                 mark_btree_node_unlocked(c_iter, 0);
 387                 c_iter->l[0].b = NULL;
 388
 389                 six_lock_write(&ck->c.lock, NULL, NULL);
 390
 391                 mutex_lock(&c->btree_key_cache.lock);
 392                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 393                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 394                         c->btree_key_cache.nr_dirty--;
 395                 }
 396
 397                 bkey_cached_evict(&c->btree_key_cache, ck);
 398                 bkey_cached_free(&c->btree_key_cache, ck);
 399                 mutex_unlock(&c->btree_key_cache.lock);
 400         }
 401 out:
 402         bch2_trans_iter_put(trans, b_iter);
 403         bch2_trans_iter_put(trans, c_iter);
 404         return ret;
 405 }
 406
 407 static void btree_key_cache_journal_flush(struct journal *j,
 408                                           struct journal_entry_pin *pin,
 409                                           u64 seq)
 410 {
 411         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 412         struct bkey_cached *ck =
 413                 container_of(pin, struct bkey_cached, journal);
 414         struct bkey_cached_key key;
 415         struct btree_trans trans;
 416
 417         int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
 418
 419         six_lock_read(&ck->c.lock, NULL, NULL);
 420         key = ck->key;
 421
 422         if (ck->journal.seq != seq ||
 423             !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 424                 six_unlock_read(&ck->c.lock);
 425                 goto unlock;
 426         }
 427         six_unlock_read(&ck->c.lock);
 428
 429         bch2_trans_init(&trans, c, 0, 0);
 430         btree_key_cache_flush_pos(&trans, key, seq, false);
 431         bch2_trans_exit(&trans);
 432 unlock:
 433         srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
 434 }
 435
 436 /*
 437  * Flush and evict a key from the key cache:
 438  */
 439 int bch2_btree_key_cache_flush(struct btree_trans *trans,
 440                                enum btree_id id, struct bpos pos)
 441 {
 442         struct bch_fs *c = trans->c;
 443         struct bkey_cached_key key = { id, pos };
 444
 445         /* Fastpath - assume it won't be found: */
 446         if (!bch2_btree_key_cache_find(c, id, pos))
 447                 return 0;
 448
 449         return btree_key_cache_flush_pos(trans, key, 0, true);
 450 }
 451
 452 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
 453                                   struct btree_iter *iter,
 454                                   struct bkey_i *insert)
 455 {
 456         struct bch_fs *c = trans->c;
 457         struct bkey_cached *ck = (void *) iter->l[0].b;
 458         bool kick_reclaim = false;
 459
 460         BUG_ON(insert->u64s > ck->u64s);
 461
 462         if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
 463                 int difference;
 464
 465                 BUG_ON(jset_u64s(insert->u64s) > trans->journal_preres.u64s);
 466
 467                 difference = jset_u64s(insert->u64s) - ck->res.u64s;
 468                 if (difference > 0) {
 469                         trans->journal_preres.u64s      -= difference;
 470                         ck->res.u64s                    += difference;
 471                 }
 472         }
 473
 474         bkey_copy(ck->k, insert);
 475         ck->valid = true;
 476
 477         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 478                 mutex_lock(&c->btree_key_cache.lock);
 479                 list_move(&ck->list, &c->btree_key_cache.dirty);
 480
 481                 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
 482                 c->btree_key_cache.nr_dirty++;
 483
 484                 if (bch2_nr_btree_keys_need_flush(c))
 485                         kick_reclaim = true;
 486
 487                 mutex_unlock(&c->btree_key_cache.lock);
 488         }
 489
 490         bch2_journal_pin_update(&c->journal, trans->journal_res.seq,
 491                                 &ck->journal, btree_key_cache_journal_flush);
 492
 493         if (kick_reclaim)
 494                 journal_reclaim_kick(&c->journal);
 495         return true;
 496 }
 497
 498 #ifdef CONFIG_BCACHEFS_DEBUG
 499 void bch2_btree_key_cache_verify_clean(struct btree_trans *trans,
 500                                enum btree_id id, struct bpos pos)
 501 {
 502         BUG_ON(bch2_btree_key_cache_find(trans->c, id, pos));
 503 }
 504 #endif
 505
 506 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 507                                            struct shrink_control *sc)
 508 {
 509         struct bch_fs *c = container_of(shrink, struct bch_fs,
 510                                         btree_key_cache.shrink);
 511         struct btree_key_cache *bc = &c->btree_key_cache;
 512         struct bkey_cached *ck, *t;
 513         size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
 514         unsigned flags;
 515
 516         /* Return -1 if we can't do anything right now */
 517         if (sc->gfp_mask & __GFP_FS)
 518                 mutex_lock(&bc->lock);
 519         else if (!mutex_trylock(&bc->lock))
 520                 return -1;
 521
 522         flags = memalloc_nofs_save();
 523
 524         /*
 525          * Newest freed entries are at the end of the list - once we hit one
 526          * that's too new to be freed, we can bail out:
 527          */
 528         list_for_each_entry_safe(ck, t, &bc->freed, list) {
 529                 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
 530                                                  ck->btree_trans_barrier_seq))
 531                         break;
 532
 533                 list_del(&ck->list);
 534                 kmem_cache_free(bch2_key_cache, ck);
 535                 bc->nr_freed--;
 536                 scanned++;
 537                 freed++;
 538         }
 539
 540         if (scanned >= nr)
 541                 goto out;
 542
 543         list_for_each_entry_safe(ck, t, &bc->clean, list) {
 544                 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 545                         clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 546                 else if (bkey_cached_lock_for_evict(ck)) {
 547                         bkey_cached_evict(bc, ck);
 548                         bkey_cached_free(bc, ck);
 549                 }
 550
 551                 scanned++;
 552                 if (scanned >= nr) {
 553                         if (&t->list != &bc->clean)
 554                                 list_move_tail(&bc->clean, &t->list);
 555                         goto out;
 556                 }
 557         }
 558 out:
 559         memalloc_nofs_restore(flags);
 560         mutex_unlock(&bc->lock);
 561
 562         return freed;
 563 }
 564
 565 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
 566                                             struct shrink_control *sc)
 567 {
 568         struct bch_fs *c = container_of(shrink, struct bch_fs,
 569                                         btree_key_cache.shrink);
 570         struct btree_key_cache *bc = &c->btree_key_cache;
 571
 572         return bc->nr_keys;
 573 }
 574
 575 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 576 {
 577         struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
 578         struct bkey_cached *ck, *n;
 579
 580         if (bc->shrink.list.next)
 581                 unregister_shrinker(&bc->shrink);
 582
 583         mutex_lock(&bc->lock);
 584         list_splice(&bc->dirty, &bc->clean);
 585
 586         list_for_each_entry_safe(ck, n, &bc->clean, list) {
 587                 cond_resched();
 588
 589                 bch2_journal_pin_drop(&c->journal, &ck->journal);
 590                 bch2_journal_preres_put(&c->journal, &ck->res);
 591
 592                 kfree(ck->k);
 593                 list_del(&ck->list);
 594                 kmem_cache_free(bch2_key_cache, ck);
 595                 bc->nr_keys--;
 596         }
 597
 598         BUG_ON(bc->nr_dirty && !bch2_journal_error(&c->journal));
 599         BUG_ON(bc->nr_keys);
 600
 601         list_for_each_entry_safe(ck, n, &bc->freed, list) {
 602                 cond_resched();
 603
 604                 list_del(&ck->list);
 605                 kmem_cache_free(bch2_key_cache, ck);
 606         }
 607         mutex_unlock(&bc->lock);
 608
 609         if (bc->table_init_done)
 610                 rhashtable_destroy(&bc->table);
 611 }
 612
 613 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
 614 {
 615         mutex_init(&c->lock);
 616         INIT_LIST_HEAD(&c->freed);
 617         INIT_LIST_HEAD(&c->clean);
 618         INIT_LIST_HEAD(&c->dirty);
 619 }
 620
 621 int bch2_fs_btree_key_cache_init(struct btree_key_cache *c)
 622 {
 623         int ret;
 624
 625         c->shrink.seeks                 = 1;
 626         c->shrink.count_objects         = bch2_btree_key_cache_count;
 627         c->shrink.scan_objects          = bch2_btree_key_cache_scan;
 628
 629         ret = register_shrinker(&c->shrink);
 630         if (ret)
 631                 return ret;
 632
 633         ret = rhashtable_init(&c->table, &bch2_btree_key_cache_params);
 634         if (ret)
 635                 return ret;
 636
 637         c->table_init_done = true;
 638         return 0;
 639 }
 640
 641 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
 642 {
 643         pr_buf(out, "nr_freed:\t%zu\n", c->nr_freed);
 644         pr_buf(out, "nr_keys:\t%zu\n",  c->nr_keys);
 645         pr_buf(out, "nr_dirty:\t%zu\n", c->nr_dirty);
 646 }
 647
 648 void bch2_btree_key_cache_exit(void)
 649 {
 650         if (bch2_key_cache)
 651                 kmem_cache_destroy(bch2_key_cache);
 652 }
 653
 654 int __init bch2_btree_key_cache_init(void)
 655 {
 656         bch2_key_cache = KMEM_CACHE(bkey_cached, 0);
 657         if (!bch2_key_cache)
 658                 return -ENOMEM;
 659
 660         return 0;
 661 }