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         if (IS_ERR(iter))
 173                 return PTR_ERR(iter);
 174
 175         k = bch2_btree_iter_peek_slot(iter);
 176         ret = bkey_err(k);
 177         if (ret) {
 178                 bch2_trans_iter_put(trans, iter);
 179                 return ret;
 180         }
 181
 182         if (!bch2_btree_node_relock(ck_iter, 0)) {
 183                 bch2_trans_iter_put(trans, iter);
 184                 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 185                 return -EINTR;
 186         }
 187
 188         if (k.k->u64s > ck->u64s) {
 189                 new_u64s = roundup_pow_of_two(k.k->u64s);
 190                 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOFS);
 191                 if (!new_k) {
 192                         bch2_trans_iter_put(trans, iter);
 193                         return -ENOMEM;
 194                 }
 195         }
 196
 197         bch2_btree_node_lock_write(ck_iter->l[0].b, ck_iter);
 198         if (new_k) {
 199                 kfree(ck->k);
 200                 ck->u64s = new_u64s;
 201                 ck->k = new_k;
 202         }
 203
 204         bkey_reassemble(ck->k, k);
 205         ck->valid = true;
 206         bch2_btree_node_unlock_write(ck_iter->l[0].b, ck_iter);
 207
 208         /* We're not likely to need this iterator again: */
 209         bch2_trans_iter_free(trans, iter);
 210
 211         return 0;
 212 }
 213
 214 static int bkey_cached_check_fn(struct six_lock *lock, void *p)
 215 {
 216         struct bkey_cached *ck = container_of(lock, struct bkey_cached, c.lock);
 217         const struct btree_iter *iter = p;
 218
 219         return ck->key.btree_id == iter->btree_id &&
 220                 !bkey_cmp(ck->key.pos, iter->pos) ? 0 : -1;
 221 }
 222
 223 __flatten
 224 int bch2_btree_iter_traverse_cached(struct btree_iter *iter)
 225 {
 226         struct btree_trans *trans = iter->trans;
 227         struct bch_fs *c = trans->c;
 228         struct bkey_cached *ck;
 229         int ret = 0;
 230
 231         BUG_ON(iter->level);
 232
 233         if (btree_node_locked(iter, 0)) {
 234                 ck = (void *) iter->l[0].b;
 235                 goto fill;
 236         }
 237 retry:
 238         ck = bch2_btree_key_cache_find(c, iter->btree_id, iter->pos);
 239         if (!ck) {
 240                 if (iter->flags & BTREE_ITER_CACHED_NOCREATE) {
 241                         iter->l[0].b = NULL;
 242                         return 0;
 243                 }
 244
 245                 mutex_lock(&c->btree_key_cache.lock);
 246                 ck = btree_key_cache_create(&c->btree_key_cache,
 247                                             iter->btree_id, iter->pos);
 248                 mutex_unlock(&c->btree_key_cache.lock);
 249
 250                 ret = PTR_ERR_OR_ZERO(ck);
 251                 if (ret)
 252                         goto err;
 253                 if (!ck)
 254                         goto retry;
 255
 256                 mark_btree_node_locked(iter, 0, SIX_LOCK_intent);
 257                 iter->locks_want = 1;
 258         } else {
 259                 enum six_lock_type lock_want = __btree_lock_want(iter, 0);
 260
 261                 if (!btree_node_lock((void *) ck, iter->pos, 0, iter, lock_want,
 262                                      bkey_cached_check_fn, iter, _THIS_IP_)) {
 263                         if (ck->key.btree_id != iter->btree_id ||
 264                             bkey_cmp(ck->key.pos, iter->pos)) {
 265                                 goto retry;
 266                         }
 267
 268                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 269                         ret = -EINTR;
 270                         goto err;
 271                 }
 272
 273                 if (ck->key.btree_id != iter->btree_id ||
 274                     bkey_cmp(ck->key.pos, iter->pos)) {
 275                         six_unlock_type(&ck->c.lock, lock_want);
 276                         goto retry;
 277                 }
 278
 279                 mark_btree_node_locked(iter, 0, lock_want);
 280         }
 281
 282         iter->l[0].lock_seq     = ck->c.lock.state.seq;
 283         iter->l[0].b            = (void *) ck;
 284 fill:
 285         if (!ck->valid && !(iter->flags & BTREE_ITER_CACHED_NOFILL)) {
 286                 if (!btree_node_intent_locked(iter, 0))
 287                         bch2_btree_iter_upgrade(iter, 1);
 288                 if (!btree_node_intent_locked(iter, 0)) {
 289                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 290                         ret = -EINTR;
 291                         goto err;
 292                 }
 293
 294                 ret = btree_key_cache_fill(trans, iter, ck);
 295                 if (ret)
 296                         goto err;
 297         }
 298
 299         if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 300                 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 301
 302         iter->uptodate = BTREE_ITER_NEED_PEEK;
 303         bch2_btree_iter_downgrade(iter);
 304         return ret;
 305 err:
 306         if (ret != -EINTR) {
 307                 btree_node_unlock(iter, 0);
 308                 iter->flags |= BTREE_ITER_ERROR;
 309                 iter->l[0].b = BTREE_ITER_NO_NODE_ERROR;
 310         }
 311         return ret;
 312 }
 313
 314 static int btree_key_cache_flush_pos(struct btree_trans *trans,
 315                                      struct bkey_cached_key key,
 316                                      u64 journal_seq,
 317                                      bool evict)
 318 {
 319         struct bch_fs *c = trans->c;
 320         struct journal *j = &c->journal;
 321         struct btree_iter *c_iter = NULL, *b_iter = NULL;
 322         struct bkey_cached *ck;
 323         int ret;
 324
 325         b_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 326                                      BTREE_ITER_SLOTS|
 327                                      BTREE_ITER_INTENT);
 328         ret = PTR_ERR_OR_ZERO(b_iter);
 329         if (ret)
 330                 goto out;
 331
 332         c_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 333                                      BTREE_ITER_CACHED|
 334                                      BTREE_ITER_CACHED_NOFILL|
 335                                      BTREE_ITER_CACHED_NOCREATE|
 336                                      BTREE_ITER_INTENT);
 337         ret = PTR_ERR_OR_ZERO(c_iter);
 338         if (ret)
 339                 goto out;
 340 retry:
 341         ret = bch2_btree_iter_traverse(c_iter);
 342         if (ret)
 343                 goto err;
 344
 345         ck = (void *) c_iter->l[0].b;
 346         if (!ck ||
 347             (journal_seq && ck->journal.seq != journal_seq))
 348                 goto out;
 349
 350         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 351                 if (!evict)
 352                         goto out;
 353                 goto evict;
 354         }
 355
 356         ret   = bch2_btree_iter_traverse(b_iter) ?:
 357                 bch2_trans_update(trans, b_iter, ck->k, BTREE_TRIGGER_NORUN) ?:
 358                 bch2_trans_commit(trans, NULL, NULL,
 359                                   BTREE_INSERT_NOUNLOCK|
 360                                   BTREE_INSERT_NOCHECK_RW|
 361                                   BTREE_INSERT_NOFAIL|
 362                                   BTREE_INSERT_USE_RESERVE|
 363                                   BTREE_INSERT_USE_ALLOC_RESERVE|
 364                                   BTREE_INSERT_JOURNAL_RESERVED|
 365                                   BTREE_INSERT_JOURNAL_RECLAIM);
 366 err:
 367         if (ret == -EINTR)
 368                 goto retry;
 369
 370         BUG_ON(ret && !bch2_journal_error(j));
 371
 372         if (ret)
 373                 goto out;
 374
 375         bch2_journal_pin_drop(j, &ck->journal);
 376         bch2_journal_preres_put(j, &ck->res);
 377
 378         if (!evict) {
 379                 mutex_lock(&c->btree_key_cache.lock);
 380                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 381                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 382                         c->btree_key_cache.nr_dirty--;
 383                 }
 384
 385                 list_move_tail(&ck->list, &c->btree_key_cache.clean);
 386                 mutex_unlock(&c->btree_key_cache.lock);
 387         } else {
 388 evict:
 389                 BUG_ON(!btree_node_intent_locked(c_iter, 0));
 390
 391                 mark_btree_node_unlocked(c_iter, 0);
 392                 c_iter->l[0].b = NULL;
 393
 394                 six_lock_write(&ck->c.lock, NULL, NULL);
 395
 396                 mutex_lock(&c->btree_key_cache.lock);
 397                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 398                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 399                         c->btree_key_cache.nr_dirty--;
 400                 }
 401
 402                 bkey_cached_evict(&c->btree_key_cache, ck);
 403                 bkey_cached_free(&c->btree_key_cache, ck);
 404                 mutex_unlock(&c->btree_key_cache.lock);
 405         }
 406 out:
 407         bch2_trans_iter_put(trans, b_iter);
 408         bch2_trans_iter_put(trans, c_iter);
 409         return ret;
 410 }
 411
 412 static void btree_key_cache_journal_flush(struct journal *j,
 413                                           struct journal_entry_pin *pin,
 414                                           u64 seq)
 415 {
 416         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 417         struct bkey_cached *ck =
 418                 container_of(pin, struct bkey_cached, journal);
 419         struct bkey_cached_key key;
 420         struct btree_trans trans;
 421
 422         int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
 423
 424         six_lock_read(&ck->c.lock, NULL, NULL);
 425         key = ck->key;
 426
 427         if (ck->journal.seq != seq ||
 428             !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 429                 six_unlock_read(&ck->c.lock);
 430                 goto unlock;
 431         }
 432         six_unlock_read(&ck->c.lock);
 433
 434         bch2_trans_init(&trans, c, 0, 0);
 435         btree_key_cache_flush_pos(&trans, key, seq, false);
 436         bch2_trans_exit(&trans);
 437 unlock:
 438         srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
 439 }
 440
 441 /*
 442  * Flush and evict a key from the key cache:
 443  */
 444 int bch2_btree_key_cache_flush(struct btree_trans *trans,
 445                                enum btree_id id, struct bpos pos)
 446 {
 447         struct bch_fs *c = trans->c;
 448         struct bkey_cached_key key = { id, pos };
 449
 450         /* Fastpath - assume it won't be found: */
 451         if (!bch2_btree_key_cache_find(c, id, pos))
 452                 return 0;
 453
 454         return btree_key_cache_flush_pos(trans, key, 0, true);
 455 }
 456
 457 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
 458                                   struct btree_iter *iter,
 459                                   struct bkey_i *insert)
 460 {
 461         struct bch_fs *c = trans->c;
 462         struct bkey_cached *ck = (void *) iter->l[0].b;
 463         bool kick_reclaim = false;
 464
 465         BUG_ON(insert->u64s > ck->u64s);
 466
 467         if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
 468                 int difference;
 469
 470                 BUG_ON(jset_u64s(insert->u64s) > trans->journal_preres.u64s);
 471
 472                 difference = jset_u64s(insert->u64s) - ck->res.u64s;
 473                 if (difference > 0) {
 474                         trans->journal_preres.u64s      -= difference;
 475                         ck->res.u64s                    += difference;
 476                 }
 477         }
 478
 479         bkey_copy(ck->k, insert);
 480         ck->valid = true;
 481
 482         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 483                 mutex_lock(&c->btree_key_cache.lock);
 484                 list_move(&ck->list, &c->btree_key_cache.dirty);
 485
 486                 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
 487                 c->btree_key_cache.nr_dirty++;
 488
 489                 if (bch2_nr_btree_keys_need_flush(c))
 490                         kick_reclaim = true;
 491
 492                 mutex_unlock(&c->btree_key_cache.lock);
 493         }
 494
 495         bch2_journal_pin_update(&c->journal, trans->journal_res.seq,
 496                                 &ck->journal, btree_key_cache_journal_flush);
 497
 498         if (kick_reclaim)
 499                 journal_reclaim_kick(&c->journal);
 500         return true;
 501 }
 502
 503 #ifdef CONFIG_BCACHEFS_DEBUG
 504 void bch2_btree_key_cache_verify_clean(struct btree_trans *trans,
 505                                enum btree_id id, struct bpos pos)
 506 {
 507         BUG_ON(bch2_btree_key_cache_find(trans->c, id, pos));
 508 }
 509 #endif
 510
 511 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 512                                            struct shrink_control *sc)
 513 {
 514         struct bch_fs *c = container_of(shrink, struct bch_fs,
 515                                         btree_key_cache.shrink);
 516         struct btree_key_cache *bc = &c->btree_key_cache;
 517         struct bkey_cached *ck, *t;
 518         size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
 519         unsigned flags;
 520
 521         /* Return -1 if we can't do anything right now */
 522         if (sc->gfp_mask & __GFP_FS)
 523                 mutex_lock(&bc->lock);
 524         else if (!mutex_trylock(&bc->lock))
 525                 return -1;
 526
 527         flags = memalloc_nofs_save();
 528
 529         /*
 530          * Newest freed entries are at the end of the list - once we hit one
 531          * that's too new to be freed, we can bail out:
 532          */
 533         list_for_each_entry_safe(ck, t, &bc->freed, list) {
 534                 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
 535                                                  ck->btree_trans_barrier_seq))
 536                         break;
 537
 538                 list_del(&ck->list);
 539                 kmem_cache_free(bch2_key_cache, ck);
 540                 bc->nr_freed--;
 541                 scanned++;
 542                 freed++;
 543         }
 544
 545         if (scanned >= nr)
 546                 goto out;
 547
 548         list_for_each_entry_safe(ck, t, &bc->clean, list) {
 549                 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 550                         clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 551                 else if (bkey_cached_lock_for_evict(ck)) {
 552                         bkey_cached_evict(bc, ck);
 553                         bkey_cached_free(bc, ck);
 554                 }
 555
 556                 scanned++;
 557                 if (scanned >= nr) {
 558                         if (&t->list != &bc->clean)
 559                                 list_move_tail(&bc->clean, &t->list);
 560                         goto out;
 561                 }
 562         }
 563 out:
 564         memalloc_nofs_restore(flags);
 565         mutex_unlock(&bc->lock);
 566
 567         return freed;
 568 }
 569
 570 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
 571                                             struct shrink_control *sc)
 572 {
 573         struct bch_fs *c = container_of(shrink, struct bch_fs,
 574                                         btree_key_cache.shrink);
 575         struct btree_key_cache *bc = &c->btree_key_cache;
 576
 577         return bc->nr_keys;
 578 }
 579
 580 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 581 {
 582         struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
 583         struct bkey_cached *ck, *n;
 584
 585         if (bc->shrink.list.next)
 586                 unregister_shrinker(&bc->shrink);
 587
 588         mutex_lock(&bc->lock);
 589         list_splice(&bc->dirty, &bc->clean);
 590
 591         list_for_each_entry_safe(ck, n, &bc->clean, list) {
 592                 bch2_journal_pin_drop(&c->journal, &ck->journal);
 593                 bch2_journal_preres_put(&c->journal, &ck->res);
 594
 595                 kfree(ck->k);
 596                 list_del(&ck->list);
 597                 kmem_cache_free(bch2_key_cache, ck);
 598                 bc->nr_keys--;
 599         }
 600
 601         BUG_ON(bc->nr_dirty && !bch2_journal_error(&c->journal));
 602         BUG_ON(bc->nr_keys);
 603
 604         list_for_each_entry_safe(ck, n, &bc->freed, list) {
 605                 list_del(&ck->list);
 606                 kmem_cache_free(bch2_key_cache, ck);
 607         }
 608         mutex_unlock(&bc->lock);
 609
 610         if (bc->table_init_done)
 611                 rhashtable_destroy(&bc->table);
 612 }
 613
 614 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
 615 {
 616         mutex_init(&c->lock);
 617         INIT_LIST_HEAD(&c->freed);
 618         INIT_LIST_HEAD(&c->clean);
 619         INIT_LIST_HEAD(&c->dirty);
 620 }
 621
 622 int bch2_fs_btree_key_cache_init(struct btree_key_cache *c)
 623 {
 624         int ret;
 625
 626         c->shrink.seeks                 = 1;
 627         c->shrink.count_objects         = bch2_btree_key_cache_count;
 628         c->shrink.scan_objects          = bch2_btree_key_cache_scan;
 629
 630         ret = register_shrinker(&c->shrink);
 631         if (ret)
 632                 return ret;
 633
 634         ret = rhashtable_init(&c->table, &bch2_btree_key_cache_params);
 635         if (ret)
 636                 return ret;
 637
 638         c->table_init_done = true;
 639         return 0;
 640 }
 641
 642 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
 643 {
 644         pr_buf(out, "nr_freed:\t%zu\n", c->nr_freed);
 645         pr_buf(out, "nr_keys:\t%zu\n",  c->nr_keys);
 646         pr_buf(out, "nr_dirty:\t%zu\n", c->nr_dirty);
 647 }
 648
 649 void bch2_btree_key_cache_exit(void)
 650 {
 651         if (bch2_key_cache)
 652                 kmem_cache_destroy(bch2_key_cache);
 653 }
 654
 655 int __init bch2_btree_key_cache_init(void)
 656 {
 657         bch2_key_cache = KMEM_CACHE(bkey_cached, 0);
 658         if (!bch2_key_cache)
 659                 return -ENOMEM;
 660
 661         return 0;
 662 }