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                 bch2_trans_iter_put(trans, iter);
 176                 return ret;
 177         }
 178
 179         if (!bch2_btree_node_relock(ck_iter, 0)) {
 180                 bch2_trans_iter_put(trans, iter);
 181                 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 182                 return -EINTR;
 183         }
 184
 185         if (k.k->u64s > ck->u64s) {
 186                 new_u64s = roundup_pow_of_two(k.k->u64s);
 187                 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOFS);
 188                 if (!new_k) {
 189                         bch2_trans_iter_put(trans, iter);
 190                         return -ENOMEM;
 191                 }
 192         }
 193
 194         bch2_btree_node_lock_write(ck_iter->l[0].b, ck_iter);
 195         if (new_k) {
 196                 kfree(ck->k);
 197                 ck->u64s = new_u64s;
 198                 ck->k = new_k;
 199         }
 200
 201         bkey_reassemble(ck->k, k);
 202         ck->valid = true;
 203         bch2_btree_node_unlock_write(ck_iter->l[0].b, ck_iter);
 204
 205         /* We're not likely to need this iterator again: */
 206         bch2_trans_iter_free(trans, iter);
 207
 208         return 0;
 209 }
 210
 211 static int bkey_cached_check_fn(struct six_lock *lock, void *p)
 212 {
 213         struct bkey_cached *ck = container_of(lock, struct bkey_cached, c.lock);
 214         const struct btree_iter *iter = p;
 215
 216         return ck->key.btree_id == iter->btree_id &&
 217                 !bkey_cmp(ck->key.pos, iter->pos) ? 0 : -1;
 218 }
 219
 220 __flatten
 221 int bch2_btree_iter_traverse_cached(struct btree_iter *iter)
 222 {
 223         struct btree_trans *trans = iter->trans;
 224         struct bch_fs *c = trans->c;
 225         struct bkey_cached *ck;
 226         int ret = 0;
 227
 228         BUG_ON(iter->level);
 229
 230         if (btree_node_locked(iter, 0)) {
 231                 ck = (void *) iter->l[0].b;
 232                 goto fill;
 233         }
 234 retry:
 235         ck = bch2_btree_key_cache_find(c, iter->btree_id, iter->pos);
 236         if (!ck) {
 237                 if (iter->flags & BTREE_ITER_CACHED_NOCREATE) {
 238                         iter->l[0].b = NULL;
 239                         return 0;
 240                 }
 241
 242                 mutex_lock(&c->btree_key_cache.lock);
 243                 ck = btree_key_cache_create(&c->btree_key_cache,
 244                                             iter->btree_id, iter->pos);
 245                 mutex_unlock(&c->btree_key_cache.lock);
 246
 247                 ret = PTR_ERR_OR_ZERO(ck);
 248                 if (ret)
 249                         goto err;
 250                 if (!ck)
 251                         goto retry;
 252
 253                 mark_btree_node_locked(iter, 0, SIX_LOCK_intent);
 254                 iter->locks_want = 1;
 255         } else {
 256                 enum six_lock_type lock_want = __btree_lock_want(iter, 0);
 257
 258                 if (!btree_node_lock((void *) ck, iter->pos, 0, iter, lock_want,
 259                                      bkey_cached_check_fn, iter, _THIS_IP_)) {
 260                         if (ck->key.btree_id != iter->btree_id ||
 261                             bkey_cmp(ck->key.pos, iter->pos)) {
 262                                 goto retry;
 263                         }
 264
 265                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 266                         ret = -EINTR;
 267                         goto err;
 268                 }
 269
 270                 if (ck->key.btree_id != iter->btree_id ||
 271                     bkey_cmp(ck->key.pos, iter->pos)) {
 272                         six_unlock_type(&ck->c.lock, lock_want);
 273                         goto retry;
 274                 }
 275
 276                 mark_btree_node_locked(iter, 0, lock_want);
 277         }
 278
 279         iter->l[0].lock_seq     = ck->c.lock.state.seq;
 280         iter->l[0].b            = (void *) ck;
 281 fill:
 282         if (!ck->valid && !(iter->flags & BTREE_ITER_CACHED_NOFILL)) {
 283                 if (!btree_node_intent_locked(iter, 0))
 284                         bch2_btree_iter_upgrade(iter, 1);
 285                 if (!btree_node_intent_locked(iter, 0)) {
 286                         trace_transaction_restart_ip(trans->ip, _THIS_IP_);
 287                         ret = -EINTR;
 288                         goto err;
 289                 }
 290
 291                 ret = btree_key_cache_fill(trans, iter, ck);
 292                 if (ret)
 293                         goto err;
 294         }
 295
 296         if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 297                 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 298
 299         iter->uptodate = BTREE_ITER_NEED_PEEK;
 300         bch2_btree_iter_downgrade(iter);
 301         return ret;
 302 err:
 303         if (ret != -EINTR) {
 304                 btree_node_unlock(iter, 0);
 305                 iter->flags |= BTREE_ITER_ERROR;
 306                 iter->l[0].b = BTREE_ITER_NO_NODE_ERROR;
 307         }
 308         return ret;
 309 }
 310
 311 static int btree_key_cache_flush_pos(struct btree_trans *trans,
 312                                      struct bkey_cached_key key,
 313                                      u64 journal_seq,
 314                                      bool evict)
 315 {
 316         struct bch_fs *c = trans->c;
 317         struct journal *j = &c->journal;
 318         struct btree_iter *c_iter = NULL, *b_iter = NULL;
 319         struct bkey_cached *ck = NULL;
 320         int ret;
 321
 322         b_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 323                                      BTREE_ITER_SLOTS|
 324                                      BTREE_ITER_INTENT);
 325         c_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
 326                                      BTREE_ITER_CACHED|
 327                                      BTREE_ITER_CACHED_NOFILL|
 328                                      BTREE_ITER_CACHED_NOCREATE|
 329                                      BTREE_ITER_INTENT);
 330 retry:
 331         ret = bch2_btree_iter_traverse(c_iter);
 332         if (ret)
 333                 goto err;
 334
 335         ck = (void *) c_iter->l[0].b;
 336         if (!ck ||
 337             (journal_seq && ck->journal.seq != journal_seq))
 338                 goto out;
 339
 340         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 341                 if (!evict)
 342                         goto out;
 343                 goto evict;
 344         }
 345
 346         ret   = bch2_btree_iter_traverse(b_iter) ?:
 347                 bch2_trans_update(trans, b_iter, ck->k, BTREE_TRIGGER_NORUN) ?:
 348                 bch2_trans_commit(trans, NULL, NULL,
 349                                   BTREE_INSERT_NOUNLOCK|
 350                                   BTREE_INSERT_NOCHECK_RW|
 351                                   BTREE_INSERT_NOFAIL|
 352                                   BTREE_INSERT_JOURNAL_RESERVED|
 353                                   BTREE_INSERT_JOURNAL_RECLAIM);
 354 err:
 355         if (ret == -EINTR)
 356                 goto retry;
 357
 358         if (ret) {
 359                 bch2_fs_fatal_err_on(!bch2_journal_error(j), c,
 360                         "error flushing key cache: %i", ret);
 361                 goto out;
 362         }
 363
 364         bch2_journal_pin_drop(j, &ck->journal);
 365         bch2_journal_preres_put(j, &ck->res);
 366
 367         if (!evict) {
 368                 mutex_lock(&c->btree_key_cache.lock);
 369                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 370                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 371                         c->btree_key_cache.nr_dirty--;
 372                 }
 373
 374                 list_move_tail(&ck->list, &c->btree_key_cache.clean);
 375                 mutex_unlock(&c->btree_key_cache.lock);
 376         } else {
 377 evict:
 378                 BUG_ON(!btree_node_intent_locked(c_iter, 0));
 379
 380                 mark_btree_node_unlocked(c_iter, 0);
 381                 c_iter->l[0].b = NULL;
 382
 383                 six_lock_write(&ck->c.lock, NULL, NULL);
 384
 385                 mutex_lock(&c->btree_key_cache.lock);
 386                 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 387                         clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
 388                         c->btree_key_cache.nr_dirty--;
 389                 }
 390
 391                 bkey_cached_evict(&c->btree_key_cache, ck);
 392                 bkey_cached_free(&c->btree_key_cache, ck);
 393                 mutex_unlock(&c->btree_key_cache.lock);
 394         }
 395 out:
 396         bch2_trans_iter_put(trans, b_iter);
 397         bch2_trans_iter_put(trans, c_iter);
 398         return ret;
 399 }
 400
 401 static void btree_key_cache_journal_flush(struct journal *j,
 402                                           struct journal_entry_pin *pin,
 403                                           u64 seq)
 404 {
 405         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 406         struct bkey_cached *ck =
 407                 container_of(pin, struct bkey_cached, journal);
 408         struct bkey_cached_key key;
 409         struct btree_trans trans;
 410
 411         int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
 412
 413         six_lock_read(&ck->c.lock, NULL, NULL);
 414         key = ck->key;
 415
 416         if (ck->journal.seq != seq ||
 417             !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 418                 six_unlock_read(&ck->c.lock);
 419                 goto unlock;
 420         }
 421         six_unlock_read(&ck->c.lock);
 422
 423         bch2_trans_init(&trans, c, 0, 0);
 424         btree_key_cache_flush_pos(&trans, key, seq, false);
 425         bch2_trans_exit(&trans);
 426 unlock:
 427         srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
 428 }
 429
 430 /*
 431  * Flush and evict a key from the key cache:
 432  */
 433 int bch2_btree_key_cache_flush(struct btree_trans *trans,
 434                                enum btree_id id, struct bpos pos)
 435 {
 436         struct bch_fs *c = trans->c;
 437         struct bkey_cached_key key = { id, pos };
 438
 439         /* Fastpath - assume it won't be found: */
 440         if (!bch2_btree_key_cache_find(c, id, pos))
 441                 return 0;
 442
 443         return btree_key_cache_flush_pos(trans, key, 0, true);
 444 }
 445
 446 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
 447                                   struct btree_iter *iter,
 448                                   struct bkey_i *insert)
 449 {
 450         struct bch_fs *c = trans->c;
 451         struct bkey_cached *ck = (void *) iter->l[0].b;
 452         bool kick_reclaim = false;
 453
 454         BUG_ON(insert->u64s > ck->u64s);
 455
 456         if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
 457                 int difference;
 458
 459                 BUG_ON(jset_u64s(insert->u64s) > trans->journal_preres.u64s);
 460
 461                 difference = jset_u64s(insert->u64s) - ck->res.u64s;
 462                 if (difference > 0) {
 463                         trans->journal_preres.u64s      -= difference;
 464                         ck->res.u64s                    += difference;
 465                 }
 466         }
 467
 468         bkey_copy(ck->k, insert);
 469         ck->valid = true;
 470
 471         if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
 472                 mutex_lock(&c->btree_key_cache.lock);
 473                 list_move(&ck->list, &c->btree_key_cache.dirty);
 474
 475                 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
 476                 c->btree_key_cache.nr_dirty++;
 477
 478                 if (bch2_nr_btree_keys_need_flush(c))
 479                         kick_reclaim = true;
 480
 481                 mutex_unlock(&c->btree_key_cache.lock);
 482         }
 483
 484         bch2_journal_pin_update(&c->journal, trans->journal_res.seq,
 485                                 &ck->journal, btree_key_cache_journal_flush);
 486
 487         if (kick_reclaim)
 488                 journal_reclaim_kick(&c->journal);
 489         return true;
 490 }
 491
 492 #ifdef CONFIG_BCACHEFS_DEBUG
 493 void bch2_btree_key_cache_verify_clean(struct btree_trans *trans,
 494                                enum btree_id id, struct bpos pos)
 495 {
 496         BUG_ON(bch2_btree_key_cache_find(trans->c, id, pos));
 497 }
 498 #endif
 499
 500 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 501                                            struct shrink_control *sc)
 502 {
 503         struct bch_fs *c = container_of(shrink, struct bch_fs,
 504                                         btree_key_cache.shrink);
 505         struct btree_key_cache *bc = &c->btree_key_cache;
 506         struct bkey_cached *ck, *t;
 507         size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
 508         unsigned flags;
 509
 510         /* Return -1 if we can't do anything right now */
 511         if (sc->gfp_mask & __GFP_FS)
 512                 mutex_lock(&bc->lock);
 513         else if (!mutex_trylock(&bc->lock))
 514                 return -1;
 515
 516         flags = memalloc_nofs_save();
 517
 518         /*
 519          * Newest freed entries are at the end of the list - once we hit one
 520          * that's too new to be freed, we can bail out:
 521          */
 522         list_for_each_entry_safe(ck, t, &bc->freed, list) {
 523                 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
 524                                                  ck->btree_trans_barrier_seq))
 525                         break;
 526
 527                 list_del(&ck->list);
 528                 kmem_cache_free(bch2_key_cache, ck);
 529                 bc->nr_freed--;
 530                 scanned++;
 531                 freed++;
 532         }
 533
 534         if (scanned >= nr)
 535                 goto out;
 536
 537         list_for_each_entry_safe(ck, t, &bc->clean, list) {
 538                 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
 539                         clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
 540                 else if (bkey_cached_lock_for_evict(ck)) {
 541                         bkey_cached_evict(bc, ck);
 542                         bkey_cached_free(bc, ck);
 543                 }
 544
 545                 scanned++;
 546                 if (scanned >= nr) {
 547                         if (&t->list != &bc->clean)
 548                                 list_move_tail(&bc->clean, &t->list);
 549                         goto out;
 550                 }
 551         }
 552 out:
 553         memalloc_nofs_restore(flags);
 554         mutex_unlock(&bc->lock);
 555
 556         return freed;
 557 }
 558
 559 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
 560                                             struct shrink_control *sc)
 561 {
 562         struct bch_fs *c = container_of(shrink, struct bch_fs,
 563                                         btree_key_cache.shrink);
 564         struct btree_key_cache *bc = &c->btree_key_cache;
 565
 566         return bc->nr_keys;
 567 }
 568
 569 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 570 {
 571         struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
 572         struct bkey_cached *ck, *n;
 573
 574         if (bc->shrink.list.next)
 575                 unregister_shrinker(&bc->shrink);
 576
 577         mutex_lock(&bc->lock);
 578         list_splice(&bc->dirty, &bc->clean);
 579
 580         list_for_each_entry_safe(ck, n, &bc->clean, list) {
 581                 cond_resched();
 582
 583                 bch2_journal_pin_drop(&c->journal, &ck->journal);
 584                 bch2_journal_preres_put(&c->journal, &ck->res);
 585
 586                 kfree(ck->k);
 587                 list_del(&ck->list);
 588                 kmem_cache_free(bch2_key_cache, ck);
 589                 bc->nr_keys--;
 590         }
 591
 592         BUG_ON(bc->nr_dirty && !bch2_journal_error(&c->journal));
 593         BUG_ON(bc->nr_keys);
 594
 595         list_for_each_entry_safe(ck, n, &bc->freed, list) {
 596                 cond_resched();
 597
 598                 list_del(&ck->list);
 599                 kmem_cache_free(bch2_key_cache, ck);
 600         }
 601         mutex_unlock(&bc->lock);
 602
 603         if (bc->table_init_done)
 604                 rhashtable_destroy(&bc->table);
 605 }
 606
 607 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
 608 {
 609         mutex_init(&c->lock);
 610         INIT_LIST_HEAD(&c->freed);
 611         INIT_LIST_HEAD(&c->clean);
 612         INIT_LIST_HEAD(&c->dirty);
 613 }
 614
 615 int bch2_fs_btree_key_cache_init(struct btree_key_cache *c)
 616 {
 617         int ret;
 618
 619         c->shrink.seeks                 = 1;
 620         c->shrink.count_objects         = bch2_btree_key_cache_count;
 621         c->shrink.scan_objects          = bch2_btree_key_cache_scan;
 622
 623         ret = register_shrinker(&c->shrink);
 624         if (ret)
 625                 return ret;
 626
 627         ret = rhashtable_init(&c->table, &bch2_btree_key_cache_params);
 628         if (ret)
 629                 return ret;
 630
 631         c->table_init_done = true;
 632         return 0;
 633 }
 634
 635 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
 636 {
 637         pr_buf(out, "nr_freed:\t%zu\n", c->nr_freed);
 638         pr_buf(out, "nr_keys:\t%zu\n",  c->nr_keys);
 639         pr_buf(out, "nr_dirty:\t%zu\n", c->nr_dirty);
 640 }
 641
 642 void bch2_btree_key_cache_exit(void)
 643 {
 644         if (bch2_key_cache)
 645                 kmem_cache_destroy(bch2_key_cache);
 646 }
 647
 648 int __init bch2_btree_key_cache_init(void)
 649 {
 650         bch2_key_cache = KMEM_CACHE(bkey_cached, 0);
 651         if (!bch2_key_cache)
 652                 return -ENOMEM;
 653
 654         return 0;
 655 }