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

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "bkey_buf.h"
   5 #include "btree_cache.h"
   6 #include "btree_io.h"
   7 #include "btree_iter.h"
   8 #include "btree_locking.h"
   9 #include "debug.h"
  10 #include "errcode.h"
  11 #include "error.h"
  12 #include "trace.h"
  13
  14 #include <linux/prefetch.h>
  15 #include <linux/sched/mm.h>
  16 #include <linux/seq_buf.h>
  17
  18 #define BTREE_CACHE_NOT_FREED_INCREMENT(counter) \
  19 do {                                             \
  20         if (shrinker_counter)                    \
  21                 bc->not_freed_##counter++;       \
  22 } while (0)
  23
  24 const char * const bch2_btree_node_flags[] = {
  25 #define x(f)    #f,
  26         BTREE_FLAGS()
  27 #undef x
  28         NULL
  29 };
  30
  31 void bch2_recalc_btree_reserve(struct bch_fs *c)
  32 {
  33         unsigned i, reserve = 16;
  34
  35         if (!c->btree_roots[0].b)
  36                 reserve += 8;
  37
  38         for (i = 0; i < BTREE_ID_NR; i++)
  39                 if (c->btree_roots[i].b)
  40                         reserve += min_t(unsigned, 1,
  41                                          c->btree_roots[i].b->c.level) * 8;
  42
  43         c->btree_cache.reserve = reserve;
  44 }
  45
  46 static inline unsigned btree_cache_can_free(struct btree_cache *bc)
  47 {
  48         return max_t(int, 0, bc->used - bc->reserve);
  49 }
  50
  51 static void btree_node_to_freedlist(struct btree_cache *bc, struct btree *b)
  52 {
  53         if (b->c.lock.readers)
  54                 list_move(&b->list, &bc->freed_pcpu);
  55         else
  56                 list_move(&b->list, &bc->freed_nonpcpu);
  57 }
  58
  59 static void btree_node_data_free(struct bch_fs *c, struct btree *b)
  60 {
  61         struct btree_cache *bc = &c->btree_cache;
  62
  63         EBUG_ON(btree_node_write_in_flight(b));
  64
  65         clear_btree_node_just_written(b);
  66
  67         kvpfree(b->data, btree_bytes(c));
  68         b->data = NULL;
  69 #ifdef __KERNEL__
  70         kvfree(b->aux_data);
  71 #else
  72         munmap(b->aux_data, btree_aux_data_bytes(b));
  73 #endif
  74         b->aux_data = NULL;
  75
  76         bc->used--;
  77
  78         btree_node_to_freedlist(bc, b);
  79 }
  80
  81 static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg,
  82                                    const void *obj)
  83 {
  84         const struct btree *b = obj;
  85         const u64 *v = arg->key;
  86
  87         return b->hash_val == *v ? 0 : 1;
  88 }
  89
  90 static const struct rhashtable_params bch_btree_cache_params = {
  91         .head_offset    = offsetof(struct btree, hash),
  92         .key_offset     = offsetof(struct btree, hash_val),
  93         .key_len        = sizeof(u64),
  94         .obj_cmpfn      = bch2_btree_cache_cmp_fn,
  95 };
  96
  97 static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
  98 {
  99         BUG_ON(b->data || b->aux_data);
 100
 101         b->data = kvpmalloc(btree_bytes(c), gfp);
 102         if (!b->data)
 103                 return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
 104 #ifdef __KERNEL__
 105         b->aux_data = kvmalloc(btree_aux_data_bytes(b), gfp);
 106 #else
 107         b->aux_data = mmap(NULL, btree_aux_data_bytes(b),
 108                            PROT_READ|PROT_WRITE|PROT_EXEC,
 109                            MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
 110         if (b->aux_data == MAP_FAILED)
 111                 b->aux_data = NULL;
 112 #endif
 113         if (!b->aux_data) {
 114                 kvpfree(b->data, btree_bytes(c));
 115                 b->data = NULL;
 116                 return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
 117         }
 118
 119         return 0;
 120 }
 121
 122 static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
 123 {
 124         struct btree *b;
 125
 126         b = kzalloc(sizeof(struct btree), gfp);
 127         if (!b)
 128                 return NULL;
 129
 130         bkey_btree_ptr_init(&b->key);
 131 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 132         lockdep_set_no_check_recursion(&b->c.lock.dep_map);
 133 #endif
 134         INIT_LIST_HEAD(&b->list);
 135         INIT_LIST_HEAD(&b->write_blocked);
 136         b->byte_order = ilog2(btree_bytes(c));
 137         return b;
 138 }
 139
 140 struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c)
 141 {
 142         struct btree_cache *bc = &c->btree_cache;
 143         struct btree *b;
 144
 145         b = __btree_node_mem_alloc(c, GFP_KERNEL);
 146         if (!b)
 147                 return NULL;
 148
 149         if (btree_node_data_alloc(c, b, GFP_KERNEL)) {
 150                 kfree(b);
 151                 return NULL;
 152         }
 153
 154         bch2_btree_lock_init(&b->c, 0);
 155
 156         bc->used++;
 157         list_add(&b->list, &bc->freeable);
 158         return b;
 159 }
 160
 161 /* Btree in memory cache - hash table */
 162
 163 void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b)
 164 {
 165         int ret = rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params);
 166
 167         BUG_ON(ret);
 168
 169         /* Cause future lookups for this node to fail: */
 170         b->hash_val = 0;
 171 }
 172
 173 int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b)
 174 {
 175         BUG_ON(b->hash_val);
 176         b->hash_val = btree_ptr_hash_val(&b->key);
 177
 178         return rhashtable_lookup_insert_fast(&bc->table, &b->hash,
 179                                              bch_btree_cache_params);
 180 }
 181
 182 int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b,
 183                                 unsigned level, enum btree_id id)
 184 {
 185         int ret;
 186
 187         b->c.level      = level;
 188         b->c.btree_id   = id;
 189
 190         mutex_lock(&bc->lock);
 191         ret = __bch2_btree_node_hash_insert(bc, b);
 192         if (!ret)
 193                 list_add_tail(&b->list, &bc->live);
 194         mutex_unlock(&bc->lock);
 195
 196         return ret;
 197 }
 198
 199 __flatten
 200 static inline struct btree *btree_cache_find(struct btree_cache *bc,
 201                                      const struct bkey_i *k)
 202 {
 203         u64 v = btree_ptr_hash_val(k);
 204
 205         return rhashtable_lookup_fast(&bc->table, &v, bch_btree_cache_params);
 206 }
 207
 208 /*
 209  * this version is for btree nodes that have already been freed (we're not
 210  * reaping a real btree node)
 211  */
 212 static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush, bool shrinker_counter)
 213 {
 214         struct btree_cache *bc = &c->btree_cache;
 215         int ret = 0;
 216
 217         lockdep_assert_held(&bc->lock);
 218 wait_on_io:
 219         if (b->flags & ((1U << BTREE_NODE_dirty)|
 220                         (1U << BTREE_NODE_read_in_flight)|
 221                         (1U << BTREE_NODE_write_in_flight))) {
 222                 if (!flush) {
 223                         if (btree_node_dirty(b))
 224                                 BTREE_CACHE_NOT_FREED_INCREMENT(dirty);
 225                         else if (btree_node_read_in_flight(b))
 226                                 BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight);
 227                         else if (btree_node_write_in_flight(b))
 228                                 BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight);
 229                         return -BCH_ERR_ENOMEM_btree_node_reclaim;
 230                 }
 231
 232                 /* XXX: waiting on IO with btree cache lock held */
 233                 bch2_btree_node_wait_on_read(b);
 234                 bch2_btree_node_wait_on_write(b);
 235         }
 236
 237         if (!six_trylock_intent(&b->c.lock)) {
 238                 BTREE_CACHE_NOT_FREED_INCREMENT(lock_intent);
 239                 return -BCH_ERR_ENOMEM_btree_node_reclaim;
 240         }
 241
 242         if (!six_trylock_write(&b->c.lock)) {
 243                 BTREE_CACHE_NOT_FREED_INCREMENT(lock_write);
 244                 goto out_unlock_intent;
 245         }
 246
 247         /* recheck under lock */
 248         if (b->flags & ((1U << BTREE_NODE_read_in_flight)|
 249                         (1U << BTREE_NODE_write_in_flight))) {
 250                 if (!flush) {
 251                         if (btree_node_read_in_flight(b))
 252                                 BTREE_CACHE_NOT_FREED_INCREMENT(read_in_flight);
 253                         else if (btree_node_write_in_flight(b))
 254                                 BTREE_CACHE_NOT_FREED_INCREMENT(write_in_flight);
 255                         goto out_unlock;
 256                 }
 257                 six_unlock_write(&b->c.lock);
 258                 six_unlock_intent(&b->c.lock);
 259                 goto wait_on_io;
 260         }
 261
 262         if (btree_node_noevict(b)) {
 263                 BTREE_CACHE_NOT_FREED_INCREMENT(noevict);
 264                 goto out_unlock;
 265         }
 266         if (btree_node_write_blocked(b)) {
 267                 BTREE_CACHE_NOT_FREED_INCREMENT(write_blocked);
 268                 goto out_unlock;
 269         }
 270         if (btree_node_will_make_reachable(b)) {
 271                 BTREE_CACHE_NOT_FREED_INCREMENT(will_make_reachable);
 272                 goto out_unlock;
 273         }
 274
 275         if (btree_node_dirty(b)) {
 276                 if (!flush) {
 277                         BTREE_CACHE_NOT_FREED_INCREMENT(dirty);
 278                         goto out_unlock;
 279                 }
 280                 /*
 281                  * Using the underscore version because we don't want to compact
 282                  * bsets after the write, since this node is about to be evicted
 283                  * - unless btree verify mode is enabled, since it runs out of
 284                  * the post write cleanup:
 285                  */
 286                 if (bch2_verify_btree_ondisk)
 287                         bch2_btree_node_write(c, b, SIX_LOCK_intent,
 288                                               BTREE_WRITE_cache_reclaim);
 289                 else
 290                         __bch2_btree_node_write(c, b,
 291                                                 BTREE_WRITE_cache_reclaim);
 292
 293                 six_unlock_write(&b->c.lock);
 294                 six_unlock_intent(&b->c.lock);
 295                 goto wait_on_io;
 296         }
 297 out:
 298         if (b->hash_val && !ret)
 299                 trace_and_count(c, btree_cache_reap, c, b);
 300         return ret;
 301 out_unlock:
 302         six_unlock_write(&b->c.lock);
 303 out_unlock_intent:
 304         six_unlock_intent(&b->c.lock);
 305         ret = -BCH_ERR_ENOMEM_btree_node_reclaim;
 306         goto out;
 307 }
 308
 309 static int btree_node_reclaim(struct bch_fs *c, struct btree *b, bool shrinker_counter)
 310 {
 311         return __btree_node_reclaim(c, b, false, shrinker_counter);
 312 }
 313
 314 static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
 315 {
 316         return __btree_node_reclaim(c, b, true, false);
 317 }
 318
 319 static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
 320                                            struct shrink_control *sc)
 321 {
 322         struct bch_fs *c = container_of(shrink, struct bch_fs,
 323                                         btree_cache.shrink);
 324         struct btree_cache *bc = &c->btree_cache;
 325         struct btree *b, *t;
 326         unsigned long nr = sc->nr_to_scan;
 327         unsigned long can_free = 0;
 328         unsigned long freed = 0;
 329         unsigned long touched = 0;
 330         unsigned i, flags;
 331         unsigned long ret = SHRINK_STOP;
 332         bool trigger_writes = atomic_read(&bc->dirty) + nr >=
 333                 bc->used * 3 / 4;
 334
 335         if (bch2_btree_shrinker_disabled)
 336                 return SHRINK_STOP;
 337
 338         mutex_lock(&bc->lock);
 339         flags = memalloc_nofs_save();
 340
 341         /*
 342          * It's _really_ critical that we don't free too many btree nodes - we
 343          * have to always leave ourselves a reserve. The reserve is how we
 344          * guarantee that allocating memory for a new btree node can always
 345          * succeed, so that inserting keys into the btree can always succeed and
 346          * IO can always make forward progress:
 347          */
 348         can_free = btree_cache_can_free(bc);
 349         nr = min_t(unsigned long, nr, can_free);
 350
 351         i = 0;
 352         list_for_each_entry_safe(b, t, &bc->freeable, list) {
 353                 /*
 354                  * Leave a few nodes on the freeable list, so that a btree split
 355                  * won't have to hit the system allocator:
 356                  */
 357                 if (++i <= 3)
 358                         continue;
 359
 360                 touched++;
 361
 362                 if (touched >= nr)
 363                         goto out;
 364
 365                 if (!btree_node_reclaim(c, b, true)) {
 366                         btree_node_data_free(c, b);
 367                         six_unlock_write(&b->c.lock);
 368                         six_unlock_intent(&b->c.lock);
 369                         freed++;
 370                         bc->freed++;
 371                 }
 372         }
 373 restart:
 374         list_for_each_entry_safe(b, t, &bc->live, list) {
 375                 touched++;
 376
 377                 if (btree_node_accessed(b)) {
 378                         clear_btree_node_accessed(b);
 379                         bc->not_freed_access_bit++;
 380                 } else if (!btree_node_reclaim(c, b, true)) {
 381                         freed++;
 382                         btree_node_data_free(c, b);
 383                         bc->freed++;
 384
 385                         bch2_btree_node_hash_remove(bc, b);
 386                         six_unlock_write(&b->c.lock);
 387                         six_unlock_intent(&b->c.lock);
 388
 389                         if (freed == nr)
 390                                 goto out_rotate;
 391                 } else if (trigger_writes &&
 392                            btree_node_dirty(b) &&
 393                            !btree_node_will_make_reachable(b) &&
 394                            !btree_node_write_blocked(b) &&
 395                            six_trylock_read(&b->c.lock)) {
 396                         list_move(&bc->live, &b->list);
 397                         mutex_unlock(&bc->lock);
 398                         __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
 399                         six_unlock_read(&b->c.lock);
 400                         if (touched >= nr)
 401                                 goto out_nounlock;
 402                         mutex_lock(&bc->lock);
 403                         goto restart;
 404                 }
 405
 406                 if (touched >= nr)
 407                         break;
 408         }
 409 out_rotate:
 410         if (&t->list != &bc->live)
 411                 list_move_tail(&bc->live, &t->list);
 412 out:
 413         mutex_unlock(&bc->lock);
 414 out_nounlock:
 415         ret = freed;
 416         memalloc_nofs_restore(flags);
 417         trace_and_count(c, btree_cache_scan, sc->nr_to_scan, can_free, ret);
 418         return ret;
 419 }
 420
 421 static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
 422                                             struct shrink_control *sc)
 423 {
 424         struct bch_fs *c = container_of(shrink, struct bch_fs,
 425                                         btree_cache.shrink);
 426         struct btree_cache *bc = &c->btree_cache;
 427
 428         if (bch2_btree_shrinker_disabled)
 429                 return 0;
 430
 431         return btree_cache_can_free(bc);
 432 }
 433
 434 static void bch2_btree_cache_shrinker_to_text(struct seq_buf *s, struct shrinker *shrink)
 435 {
 436         struct bch_fs *c = container_of(shrink, struct bch_fs,
 437                                         btree_cache.shrink);
 438         char *cbuf;
 439         size_t buflen = seq_buf_get_buf(s, &cbuf);
 440         struct printbuf out = PRINTBUF_EXTERN(cbuf, buflen);
 441
 442         bch2_btree_cache_to_text(&out, &c->btree_cache);
 443         seq_buf_commit(s, out.pos);
 444 }
 445
 446 void bch2_fs_btree_cache_exit(struct bch_fs *c)
 447 {
 448         struct btree_cache *bc = &c->btree_cache;
 449         struct btree *b;
 450         unsigned i, flags;
 451
 452         if (bc->shrink.list.next)
 453                 unregister_shrinker(&bc->shrink);
 454
 455         /* vfree() can allocate memory: */
 456         flags = memalloc_nofs_save();
 457         mutex_lock(&bc->lock);
 458
 459         if (c->verify_data)
 460                 list_move(&c->verify_data->list, &bc->live);
 461
 462         kvpfree(c->verify_ondisk, btree_bytes(c));
 463
 464         for (i = 0; i < BTREE_ID_NR; i++)
 465                 if (c->btree_roots[i].b)
 466                         list_add(&c->btree_roots[i].b->list, &bc->live);
 467
 468         list_splice(&bc->freeable, &bc->live);
 469
 470         while (!list_empty(&bc->live)) {
 471                 b = list_first_entry(&bc->live, struct btree, list);
 472
 473                 BUG_ON(btree_node_read_in_flight(b) ||
 474                        btree_node_write_in_flight(b));
 475
 476                 if (btree_node_dirty(b))
 477                         bch2_btree_complete_write(c, b, btree_current_write(b));
 478                 clear_btree_node_dirty_acct(c, b);
 479
 480                 btree_node_data_free(c, b);
 481         }
 482
 483         BUG_ON(atomic_read(&c->btree_cache.dirty));
 484
 485         list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu);
 486
 487         while (!list_empty(&bc->freed_nonpcpu)) {
 488                 b = list_first_entry(&bc->freed_nonpcpu, struct btree, list);
 489                 list_del(&b->list);
 490                 six_lock_exit(&b->c.lock);
 491                 kfree(b);
 492         }
 493
 494         mutex_unlock(&bc->lock);
 495         memalloc_nofs_restore(flags);
 496
 497         if (bc->table_init_done)
 498                 rhashtable_destroy(&bc->table);
 499 }
 500
 501 int bch2_fs_btree_cache_init(struct bch_fs *c)
 502 {
 503         struct btree_cache *bc = &c->btree_cache;
 504         unsigned i;
 505         int ret = 0;
 506
 507         pr_verbose_init(c->opts, "");
 508
 509         ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
 510         if (ret)
 511                 goto out;
 512
 513         bc->table_init_done = true;
 514
 515         bch2_recalc_btree_reserve(c);
 516
 517         for (i = 0; i < bc->reserve; i++)
 518                 if (!__bch2_btree_node_mem_alloc(c)) {
 519                         ret = -BCH_ERR_ENOMEM_fs_btree_cache_init;
 520                         goto out;
 521                 }
 522
 523         list_splice_init(&bc->live, &bc->freeable);
 524
 525         mutex_init(&c->verify_lock);
 526
 527         bc->shrink.count_objects        = bch2_btree_cache_count;
 528         bc->shrink.scan_objects         = bch2_btree_cache_scan;
 529         bc->shrink.to_text              = bch2_btree_cache_shrinker_to_text;
 530         bc->shrink.seeks                = 4;
 531         ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
 532 out:
 533         pr_verbose_init(c->opts, "ret %i", ret);
 534         return ret;
 535 }
 536
 537 void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
 538 {
 539         mutex_init(&bc->lock);
 540         INIT_LIST_HEAD(&bc->live);
 541         INIT_LIST_HEAD(&bc->freeable);
 542         INIT_LIST_HEAD(&bc->freed_pcpu);
 543         INIT_LIST_HEAD(&bc->freed_nonpcpu);
 544 }
 545
 546 /*
 547  * We can only have one thread cannibalizing other cached btree nodes at a time,
 548  * or we'll deadlock. We use an open coded mutex to ensure that, which a
 549  * cannibalize_bucket() will take. This means every time we unlock the root of
 550  * the btree, we need to release this lock if we have it held.
 551  */
 552 void bch2_btree_cache_cannibalize_unlock(struct bch_fs *c)
 553 {
 554         struct btree_cache *bc = &c->btree_cache;
 555
 556         if (bc->alloc_lock == current) {
 557                 trace_and_count(c, btree_cache_cannibalize_unlock, c);
 558                 bc->alloc_lock = NULL;
 559                 closure_wake_up(&bc->alloc_wait);
 560         }
 561 }
 562
 563 int bch2_btree_cache_cannibalize_lock(struct bch_fs *c, struct closure *cl)
 564 {
 565         struct btree_cache *bc = &c->btree_cache;
 566         struct task_struct *old;
 567
 568         old = cmpxchg(&bc->alloc_lock, NULL, current);
 569         if (old == NULL || old == current)
 570                 goto success;
 571
 572         if (!cl) {
 573                 trace_and_count(c, btree_cache_cannibalize_lock_fail, c);
 574                 return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock;
 575         }
 576
 577         closure_wait(&bc->alloc_wait, cl);
 578
 579         /* Try again, after adding ourselves to waitlist */
 580         old = cmpxchg(&bc->alloc_lock, NULL, current);
 581         if (old == NULL || old == current) {
 582                 /* We raced */
 583                 closure_wake_up(&bc->alloc_wait);
 584                 goto success;
 585         }
 586
 587         trace_and_count(c, btree_cache_cannibalize_lock_fail, c);
 588         return -BCH_ERR_btree_cache_cannibalize_lock_blocked;
 589
 590 success:
 591         trace_and_count(c, btree_cache_cannibalize_lock, c);
 592         return 0;
 593 }
 594
 595 static struct btree *btree_node_cannibalize(struct bch_fs *c)
 596 {
 597         struct btree_cache *bc = &c->btree_cache;
 598         struct btree *b;
 599
 600         list_for_each_entry_reverse(b, &bc->live, list)
 601                 if (!btree_node_reclaim(c, b, false))
 602                         return b;
 603
 604         while (1) {
 605                 list_for_each_entry_reverse(b, &bc->live, list)
 606                         if (!btree_node_write_and_reclaim(c, b))
 607                                 return b;
 608
 609                 /*
 610                  * Rare case: all nodes were intent-locked.
 611                  * Just busy-wait.
 612                  */
 613                 WARN_ONCE(1, "btree cache cannibalize failed\n");
 614                 cond_resched();
 615         }
 616 }
 617
 618 struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks)
 619 {
 620         struct bch_fs *c = trans->c;
 621         struct btree_cache *bc = &c->btree_cache;
 622         struct list_head *freed = pcpu_read_locks
 623                 ? &bc->freed_pcpu
 624                 : &bc->freed_nonpcpu;
 625         struct btree *b, *b2;
 626         u64 start_time = local_clock();
 627         unsigned flags;
 628
 629         flags = memalloc_nofs_save();
 630         mutex_lock(&bc->lock);
 631
 632         /*
 633          * We never free struct btree itself, just the memory that holds the on
 634          * disk node. Check the freed list before allocating a new one:
 635          */
 636         list_for_each_entry(b, freed, list)
 637                 if (!btree_node_reclaim(c, b, false)) {
 638                         list_del_init(&b->list);
 639                         goto got_node;
 640                 }
 641
 642         b = __btree_node_mem_alloc(c, __GFP_NOWARN);
 643         if (!b) {
 644                 mutex_unlock(&bc->lock);
 645                 b = __btree_node_mem_alloc(c, GFP_KERNEL);
 646                 if (!b)
 647                         goto err;
 648                 mutex_lock(&bc->lock);
 649         }
 650
 651         bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
 652
 653         BUG_ON(!six_trylock_intent(&b->c.lock));
 654         BUG_ON(!six_trylock_write(&b->c.lock));
 655 got_node:
 656
 657         /*
 658          * btree_free() doesn't free memory; it sticks the node on the end of
 659          * the list. Check if there's any freed nodes there:
 660          */
 661         list_for_each_entry(b2, &bc->freeable, list)
 662                 if (!btree_node_reclaim(c, b2, false)) {
 663                         swap(b->data, b2->data);
 664                         swap(b->aux_data, b2->aux_data);
 665                         btree_node_to_freedlist(bc, b2);
 666                         six_unlock_write(&b2->c.lock);
 667                         six_unlock_intent(&b2->c.lock);
 668                         goto got_mem;
 669                 }
 670
 671         mutex_unlock(&bc->lock);
 672
 673         if (btree_node_data_alloc(c, b, __GFP_NOWARN|GFP_KERNEL))
 674                 goto err;
 675
 676         mutex_lock(&bc->lock);
 677         bc->used++;
 678 got_mem:
 679         mutex_unlock(&bc->lock);
 680
 681         BUG_ON(btree_node_hashed(b));
 682         BUG_ON(btree_node_dirty(b));
 683         BUG_ON(btree_node_write_in_flight(b));
 684 out:
 685         b->flags                = 0;
 686         b->written              = 0;
 687         b->nsets                = 0;
 688         b->sib_u64s[0]          = 0;
 689         b->sib_u64s[1]          = 0;
 690         b->whiteout_u64s        = 0;
 691         bch2_btree_keys_init(b);
 692         set_btree_node_accessed(b);
 693
 694         bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
 695                                start_time);
 696
 697         memalloc_nofs_restore(flags);
 698         return b;
 699 err:
 700         mutex_lock(&bc->lock);
 701
 702         /* Try to cannibalize another cached btree node: */
 703         if (bc->alloc_lock == current) {
 704                 b2 = btree_node_cannibalize(c);
 705                 clear_btree_node_just_written(b2);
 706                 bch2_btree_node_hash_remove(bc, b2);
 707
 708                 if (b) {
 709                         swap(b->data, b2->data);
 710                         swap(b->aux_data, b2->aux_data);
 711                         btree_node_to_freedlist(bc, b2);
 712                         six_unlock_write(&b2->c.lock);
 713                         six_unlock_intent(&b2->c.lock);
 714                 } else {
 715                         b = b2;
 716                         list_del_init(&b->list);
 717                 }
 718
 719                 mutex_unlock(&bc->lock);
 720
 721                 trace_and_count(c, btree_cache_cannibalize, c);
 722                 goto out;
 723         }
 724
 725         mutex_unlock(&bc->lock);
 726         memalloc_nofs_restore(flags);
 727         return ERR_PTR(-BCH_ERR_ENOMEM_btree_node_mem_alloc);
 728 }
 729
 730 /* Slowpath, don't want it inlined into btree_iter_traverse() */
 731 static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
 732                                 struct btree_path *path,
 733                                 const struct bkey_i *k,
 734                                 enum btree_id btree_id,
 735                                 unsigned level,
 736                                 enum six_lock_type lock_type,
 737                                 bool sync)
 738 {
 739         struct bch_fs *c = trans->c;
 740         struct btree_cache *bc = &c->btree_cache;
 741         struct btree *b;
 742         u32 seq;
 743
 744         BUG_ON(level + 1 >= BTREE_MAX_DEPTH);
 745         /*
 746          * Parent node must be locked, else we could read in a btree node that's
 747          * been freed:
 748          */
 749         if (path && !bch2_btree_node_relock(trans, path, level + 1)) {
 750                 trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path);
 751                 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock));
 752         }
 753
 754         b = bch2_btree_node_mem_alloc(trans, level != 0);
 755
 756         if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {
 757                 trans->memory_allocation_failure = true;
 758                 trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);
 759                 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
 760         }
 761
 762         if (IS_ERR(b))
 763                 return b;
 764
 765         /*
 766          * Btree nodes read in from disk should not have the accessed bit set
 767          * initially, so that linear scans don't thrash the cache:
 768          */
 769         clear_btree_node_accessed(b);
 770
 771         bkey_copy(&b->key, k);
 772         if (bch2_btree_node_hash_insert(bc, b, level, btree_id)) {
 773                 /* raced with another fill: */
 774
 775                 /* mark as unhashed... */
 776                 b->hash_val = 0;
 777
 778                 mutex_lock(&bc->lock);
 779                 list_add(&b->list, &bc->freeable);
 780                 mutex_unlock(&bc->lock);
 781
 782                 six_unlock_write(&b->c.lock);
 783                 six_unlock_intent(&b->c.lock);
 784                 return NULL;
 785         }
 786
 787         set_btree_node_read_in_flight(b);
 788
 789         six_unlock_write(&b->c.lock);
 790         seq = six_lock_seq(&b->c.lock);
 791         six_unlock_intent(&b->c.lock);
 792
 793         /* Unlock before doing IO: */
 794         if (trans && sync)
 795                 bch2_trans_unlock(trans);
 796
 797         bch2_btree_node_read(c, b, sync);
 798
 799         if (!sync)
 800                 return NULL;
 801
 802         if (path) {
 803                 int ret = bch2_trans_relock(trans) ?:
 804                         bch2_btree_path_relock_intent(trans, path);
 805                 if (ret) {
 806                         BUG_ON(!trans->restarted);
 807                         return ERR_PTR(ret);
 808                 }
 809         }
 810
 811         if (!six_relock_type(&b->c.lock, lock_type, seq)) {
 812                 if (path)
 813                         trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
 814                 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));
 815         }
 816
 817         return b;
 818 }
 819
 820 static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
 821 {
 822         struct printbuf buf = PRINTBUF;
 823
 824         if (!test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags))
 825                 return;
 826
 827         prt_printf(&buf,
 828                "btree node header doesn't match ptr\n"
 829                "btree %s level %u\n"
 830                "ptr: ",
 831                bch2_btree_ids[b->c.btree_id], b->c.level);
 832         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
 833
 834         prt_printf(&buf, "\nheader: btree %s level %llu\n"
 835                "min ",
 836                bch2_btree_ids[BTREE_NODE_ID(b->data)],
 837                BTREE_NODE_LEVEL(b->data));
 838         bch2_bpos_to_text(&buf, b->data->min_key);
 839
 840         prt_printf(&buf, "\nmax ");
 841         bch2_bpos_to_text(&buf, b->data->max_key);
 842
 843         bch2_fs_inconsistent(c, "%s", buf.buf);
 844         printbuf_exit(&buf);
 845 }
 846
 847 static inline void btree_check_header(struct bch_fs *c, struct btree *b)
 848 {
 849         if (b->c.btree_id != BTREE_NODE_ID(b->data) ||
 850             b->c.level != BTREE_NODE_LEVEL(b->data) ||
 851             !bpos_eq(b->data->max_key, b->key.k.p) ||
 852             (b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
 853              !bpos_eq(b->data->min_key,
 854                       bkey_i_to_btree_ptr_v2(&b->key)->v.min_key)))
 855                 btree_bad_header(c, b);
 856 }
 857
 858 static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
 859                                            const struct bkey_i *k, unsigned level,
 860                                            enum six_lock_type lock_type,
 861                                            unsigned long trace_ip)
 862 {
 863         struct bch_fs *c = trans->c;
 864         struct btree_cache *bc = &c->btree_cache;
 865         struct btree *b;
 866         struct bset_tree *t;
 867         int ret;
 868
 869         EBUG_ON(level >= BTREE_MAX_DEPTH);
 870 retry:
 871         b = btree_cache_find(bc, k);
 872         if (unlikely(!b)) {
 873                 /*
 874                  * We must have the parent locked to call bch2_btree_node_fill(),
 875                  * else we could read in a btree node from disk that's been
 876                  * freed:
 877                  */
 878                 b = bch2_btree_node_fill(trans, path, k, path->btree_id,
 879                                          level, lock_type, true);
 880
 881                 /* We raced and found the btree node in the cache */
 882                 if (!b)
 883                         goto retry;
 884
 885                 if (IS_ERR(b))
 886                         return b;
 887         } else {
 888                 if (btree_node_read_locked(path, level + 1))
 889                         btree_node_unlock(trans, path, level + 1);
 890
 891                 ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
 892                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 893                         return ERR_PTR(ret);
 894
 895                 BUG_ON(ret);
 896
 897                 if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
 898                              b->c.level != level ||
 899                              race_fault())) {
 900                         six_unlock_type(&b->c.lock, lock_type);
 901                         if (bch2_btree_node_relock(trans, path, level + 1))
 902                                 goto retry;
 903
 904                         trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
 905                         return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
 906                 }
 907
 908                 /* avoid atomic set bit if it's not needed: */
 909                 if (!btree_node_accessed(b))
 910                         set_btree_node_accessed(b);
 911         }
 912
 913         if (unlikely(btree_node_read_in_flight(b))) {
 914                 u32 seq = six_lock_seq(&b->c.lock);
 915
 916                 six_unlock_type(&b->c.lock, lock_type);
 917                 bch2_trans_unlock(trans);
 918
 919                 bch2_btree_node_wait_on_read(b);
 920
 921                 /*
 922                  * should_be_locked is not set on this path yet, so we need to
 923                  * relock it specifically:
 924                  */
 925                 if (trans) {
 926                         int ret = bch2_trans_relock(trans) ?:
 927                                 bch2_btree_path_relock_intent(trans, path);
 928                         if (ret) {
 929                                 BUG_ON(!trans->restarted);
 930                                 return ERR_PTR(ret);
 931                         }
 932                 }
 933
 934                 if (!six_relock_type(&b->c.lock, lock_type, seq))
 935                         goto retry;
 936         }
 937
 938         prefetch(b->aux_data);
 939
 940         for_each_bset(b, t) {
 941                 void *p = (u64 *) b->aux_data + t->aux_data_offset;
 942
 943                 prefetch(p + L1_CACHE_BYTES * 0);
 944                 prefetch(p + L1_CACHE_BYTES * 1);
 945                 prefetch(p + L1_CACHE_BYTES * 2);
 946         }
 947
 948         if (unlikely(btree_node_read_error(b))) {
 949                 six_unlock_type(&b->c.lock, lock_type);
 950                 return ERR_PTR(-EIO);
 951         }
 952
 953         EBUG_ON(b->c.btree_id != path->btree_id);
 954         EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
 955         btree_check_header(c, b);
 956
 957         return b;
 958 }
 959
 960 /**
 961  * bch_btree_node_get - find a btree node in the cache and lock it, reading it
 962  * in from disk if necessary.
 963  *
 964  * The btree node will have either a read or a write lock held, depending on
 965  * the @write parameter.
 966  */
 967 struct btree *bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
 968                                   const struct bkey_i *k, unsigned level,
 969                                   enum six_lock_type lock_type,
 970                                   unsigned long trace_ip)
 971 {
 972         struct bch_fs *c = trans->c;
 973         struct btree *b;
 974         struct bset_tree *t;
 975         int ret;
 976
 977         EBUG_ON(level >= BTREE_MAX_DEPTH);
 978
 979         b = btree_node_mem_ptr(k);
 980
 981         /*
 982          * Check b->hash_val _before_ calling btree_node_lock() - this might not
 983          * be the node we want anymore, and trying to lock the wrong node could
 984          * cause an unneccessary transaction restart:
 985          */
 986         if (unlikely(!c->opts.btree_node_mem_ptr_optimization ||
 987                      !b ||
 988                      b->hash_val != btree_ptr_hash_val(k)))
 989                 return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
 990
 991         if (btree_node_read_locked(path, level + 1))
 992                 btree_node_unlock(trans, path, level + 1);
 993
 994         ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
 995         if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 996                 return ERR_PTR(ret);
 997
 998         BUG_ON(ret);
 999
1000         if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
1001                      b->c.level != level ||
1002                      race_fault())) {
1003                 six_unlock_type(&b->c.lock, lock_type);
1004                 if (bch2_btree_node_relock(trans, path, level + 1))
1005                         return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
1006
1007                 trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
1008                 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
1009         }
1010
1011         if (unlikely(btree_node_read_in_flight(b))) {
1012                 u32 seq = six_lock_seq(&b->c.lock);
1013
1014                 six_unlock_type(&b->c.lock, lock_type);
1015                 bch2_trans_unlock(trans);
1016
1017                 bch2_btree_node_wait_on_read(b);
1018
1019                 /*
1020                  * should_be_locked is not set on this path yet, so we need to
1021                  * relock it specifically:
1022                  */
1023                 if (trans) {
1024                         int ret = bch2_trans_relock(trans) ?:
1025                                 bch2_btree_path_relock_intent(trans, path);
1026                         if (ret) {
1027                                 BUG_ON(!trans->restarted);
1028                                 return ERR_PTR(ret);
1029                         }
1030                 }
1031
1032                 if (!six_relock_type(&b->c.lock, lock_type, seq))
1033                         return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
1034         }
1035
1036         prefetch(b->aux_data);
1037
1038         for_each_bset(b, t) {
1039                 void *p = (u64 *) b->aux_data + t->aux_data_offset;
1040
1041                 prefetch(p + L1_CACHE_BYTES * 0);
1042                 prefetch(p + L1_CACHE_BYTES * 1);
1043                 prefetch(p + L1_CACHE_BYTES * 2);
1044         }
1045
1046         /* avoid atomic set bit if it's not needed: */
1047         if (!btree_node_accessed(b))
1048                 set_btree_node_accessed(b);
1049
1050         if (unlikely(btree_node_read_error(b))) {
1051                 six_unlock_type(&b->c.lock, lock_type);
1052                 return ERR_PTR(-EIO);
1053         }
1054
1055         EBUG_ON(b->c.btree_id != path->btree_id);
1056         EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
1057         btree_check_header(c, b);
1058
1059         return b;
1060 }
1061
1062 struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
1063                                          const struct bkey_i *k,
1064                                          enum btree_id btree_id,
1065                                          unsigned level,
1066                                          bool nofill)
1067 {
1068         struct bch_fs *c = trans->c;
1069         struct btree_cache *bc = &c->btree_cache;
1070         struct btree *b;
1071         struct bset_tree *t;
1072         int ret;
1073
1074         EBUG_ON(level >= BTREE_MAX_DEPTH);
1075
1076         if (c->opts.btree_node_mem_ptr_optimization) {
1077                 b = btree_node_mem_ptr(k);
1078                 if (b)
1079                         goto lock_node;
1080         }
1081 retry:
1082         b = btree_cache_find(bc, k);
1083         if (unlikely(!b)) {
1084                 if (nofill)
1085                         goto out;
1086
1087                 b = bch2_btree_node_fill(trans, NULL, k, btree_id,
1088                                          level, SIX_LOCK_read, true);
1089
1090                 /* We raced and found the btree node in the cache */
1091                 if (!b)
1092                         goto retry;
1093
1094                 if (IS_ERR(b) &&
1095                     !bch2_btree_cache_cannibalize_lock(c, NULL))
1096                         goto retry;
1097
1098                 if (IS_ERR(b))
1099                         goto out;
1100         } else {
1101 lock_node:
1102                 ret = btree_node_lock_nopath(trans, &b->c, SIX_LOCK_read, _THIS_IP_);
1103                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
1104                         return ERR_PTR(ret);
1105
1106                 BUG_ON(ret);
1107
1108                 if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
1109                              b->c.btree_id != btree_id ||
1110                              b->c.level != level)) {
1111                         six_unlock_read(&b->c.lock);
1112                         goto retry;
1113                 }
1114         }
1115
1116         /* XXX: waiting on IO with btree locks held: */
1117         __bch2_btree_node_wait_on_read(b);
1118
1119         prefetch(b->aux_data);
1120
1121         for_each_bset(b, t) {
1122                 void *p = (u64 *) b->aux_data + t->aux_data_offset;
1123
1124                 prefetch(p + L1_CACHE_BYTES * 0);
1125                 prefetch(p + L1_CACHE_BYTES * 1);
1126                 prefetch(p + L1_CACHE_BYTES * 2);
1127         }
1128
1129         /* avoid atomic set bit if it's not needed: */
1130         if (!btree_node_accessed(b))
1131                 set_btree_node_accessed(b);
1132
1133         if (unlikely(btree_node_read_error(b))) {
1134                 six_unlock_read(&b->c.lock);
1135                 b = ERR_PTR(-EIO);
1136                 goto out;
1137         }
1138
1139         EBUG_ON(b->c.btree_id != btree_id);
1140         EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
1141         btree_check_header(c, b);
1142 out:
1143         bch2_btree_cache_cannibalize_unlock(c);
1144         return b;
1145 }
1146
1147 int bch2_btree_node_prefetch(struct btree_trans *trans,
1148                              struct btree_path *path,
1149                              const struct bkey_i *k,
1150                              enum btree_id btree_id, unsigned level)
1151 {
1152         struct bch_fs *c = trans->c;
1153         struct btree_cache *bc = &c->btree_cache;
1154         struct btree *b;
1155
1156         BUG_ON(trans && !btree_node_locked(path, level + 1));
1157         BUG_ON(level >= BTREE_MAX_DEPTH);
1158
1159         b = btree_cache_find(bc, k);
1160         if (b)
1161                 return 0;
1162
1163         b = bch2_btree_node_fill(trans, path, k, btree_id,
1164                                  level, SIX_LOCK_read, false);
1165         return PTR_ERR_OR_ZERO(b);
1166 }
1167
1168 void bch2_btree_node_evict(struct btree_trans *trans, const struct bkey_i *k)
1169 {
1170         struct bch_fs *c = trans->c;
1171         struct btree_cache *bc = &c->btree_cache;
1172         struct btree *b;
1173
1174         b = btree_cache_find(bc, k);
1175         if (!b)
1176                 return;
1177 wait_on_io:
1178         /* not allowed to wait on io with btree locks held: */
1179
1180         /* XXX we're called from btree_gc which will be holding other btree
1181          * nodes locked
1182          */
1183         __bch2_btree_node_wait_on_read(b);
1184         __bch2_btree_node_wait_on_write(b);
1185
1186         btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
1187         btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
1188
1189         if (btree_node_dirty(b)) {
1190                 __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
1191                 six_unlock_write(&b->c.lock);
1192                 six_unlock_intent(&b->c.lock);
1193                 goto wait_on_io;
1194         }
1195
1196         BUG_ON(btree_node_dirty(b));
1197
1198         mutex_lock(&bc->lock);
1199         btree_node_data_free(c, b);
1200         bch2_btree_node_hash_remove(bc, b);
1201         mutex_unlock(&bc->lock);
1202
1203         six_unlock_write(&b->c.lock);
1204         six_unlock_intent(&b->c.lock);
1205 }
1206
1207 void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
1208                              const struct btree *b)
1209 {
1210         const struct bkey_format *f = &b->format;
1211         struct bset_stats stats;
1212
1213         memset(&stats, 0, sizeof(stats));
1214
1215         bch2_btree_keys_stats(b, &stats);
1216
1217         prt_printf(out, "l %u ", b->c.level);
1218         bch2_bpos_to_text(out, b->data->min_key);
1219         prt_printf(out, " - ");
1220         bch2_bpos_to_text(out, b->data->max_key);
1221         prt_printf(out, ":\n"
1222                "    ptrs: ");
1223         bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
1224
1225         prt_printf(out, "\n"
1226                "    format: u64s %u fields %u %u %u %u %u\n"
1227                "    unpack fn len: %u\n"
1228                "    bytes used %zu/%zu (%zu%% full)\n"
1229                "    sib u64s: %u, %u (merge threshold %u)\n"
1230                "    nr packed keys %u\n"
1231                "    nr unpacked keys %u\n"
1232                "    floats %zu\n"
1233                "    failed unpacked %zu\n",
1234                f->key_u64s,
1235                f->bits_per_field[0],
1236                f->bits_per_field[1],
1237                f->bits_per_field[2],
1238                f->bits_per_field[3],
1239                f->bits_per_field[4],
1240                b->unpack_fn_len,
1241                b->nr.live_u64s * sizeof(u64),
1242                btree_bytes(c) - sizeof(struct btree_node),
1243                b->nr.live_u64s * 100 / btree_max_u64s(c),
1244                b->sib_u64s[0],
1245                b->sib_u64s[1],
1246                c->btree_foreground_merge_threshold,
1247                b->nr.packed_keys,
1248                b->nr.unpacked_keys,
1249                stats.floats,
1250                stats.failed);
1251 }
1252
1253 void bch2_btree_cache_to_text(struct printbuf *out, const struct btree_cache *bc)
1254 {
1255         prt_printf(out, "nr nodes:\t\t%u\n", bc->used);
1256         prt_printf(out, "nr dirty:\t\t%u\n", atomic_read(&bc->dirty));
1257         prt_printf(out, "cannibalize lock:\t%p\n", bc->alloc_lock);
1258
1259         prt_printf(out, "freed:\t\t\t\t%u\n", bc->freed);
1260         prt_printf(out, "not freed, dirty:\t\t%u\n", bc->not_freed_dirty);
1261         prt_printf(out, "not freed, write in flight:\t%u\n", bc->not_freed_write_in_flight);
1262         prt_printf(out, "not freed, read in flight:\t%u\n", bc->not_freed_read_in_flight);
1263         prt_printf(out, "not freed, lock intent failed:\t%u\n", bc->not_freed_lock_intent);
1264         prt_printf(out, "not freed, lock write failed:\t%u\n", bc->not_freed_lock_write);
1265         prt_printf(out, "not freed, access bit:\t\t%u\n", bc->not_freed_access_bit);
1266         prt_printf(out, "not freed, no evict failed:\t%u\n", bc->not_freed_noevict);
1267         prt_printf(out, "not freed, write blocked:\t%u\n", bc->not_freed_write_blocked);
1268         prt_printf(out, "not freed, will make reachable:\t%u\n", bc->not_freed_will_make_reachable);
1269
1270 }