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"
10 #include "journal_reclaim.h"
12 #include <linux/sched/mm.h>
13 #include <trace/events/bcachefs.h>
15 static struct kmem_cache *bch2_key_cache;
17 static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
20 const struct bkey_cached *ck = obj;
21 const struct bkey_cached_key *key = arg->key;
23 return cmp_int(ck->key.btree_id, key->btree_id) ?:
24 bpos_cmp(ck->key.pos, key->pos);
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,
35 inline struct bkey_cached *
36 bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
38 struct bkey_cached_key key = {
43 return rhashtable_lookup_fast(&c->btree_key_cache.table, &key,
44 bch2_btree_key_cache_params);
47 static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
49 if (!six_trylock_intent(&ck->c.lock))
52 if (!six_trylock_write(&ck->c.lock)) {
53 six_unlock_intent(&ck->c.lock);
57 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
58 six_unlock_write(&ck->c.lock);
59 six_unlock_intent(&ck->c.lock);
66 static void bkey_cached_evict(struct btree_key_cache *c,
67 struct bkey_cached *ck)
69 BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
70 bch2_btree_key_cache_params));
71 memset(&ck->key, ~0, sizeof(ck->key));
73 atomic_long_dec(&c->nr_keys);
76 static void bkey_cached_free(struct btree_key_cache *bc,
77 struct bkey_cached *ck)
79 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
81 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
83 ck->btree_trans_barrier_seq =
84 start_poll_synchronize_srcu(&c->btree_trans_barrier);
86 list_move_tail(&ck->list, &bc->freed);
93 six_unlock_write(&ck->c.lock);
94 six_unlock_intent(&ck->c.lock);
97 static struct bkey_cached *
98 bkey_cached_alloc(struct btree_key_cache *c)
100 struct bkey_cached *ck;
102 ck = kmem_cache_alloc(bch2_key_cache, GFP_NOFS|__GFP_ZERO);
104 INIT_LIST_HEAD(&ck->list);
105 six_lock_init(&ck->c.lock);
106 BUG_ON(!six_trylock_intent(&ck->c.lock));
107 BUG_ON(!six_trylock_write(&ck->c.lock));
114 static struct bkey_cached *
115 bkey_cached_reuse(struct btree_key_cache *c)
117 struct bucket_table *tbl;
118 struct rhash_head *pos;
119 struct bkey_cached *ck;
122 mutex_lock(&c->lock);
123 list_for_each_entry_reverse(ck, &c->freed, list)
124 if (bkey_cached_lock_for_evict(ck)) {
127 mutex_unlock(&c->lock);
130 mutex_unlock(&c->lock);
133 tbl = rht_dereference_rcu(c->table.tbl, &c->table);
134 for (i = 0; i < tbl->size; i++)
135 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
136 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
137 bkey_cached_lock_for_evict(ck)) {
138 bkey_cached_evict(c, ck);
148 static struct bkey_cached *
149 btree_key_cache_create(struct btree_key_cache *c,
150 enum btree_id btree_id,
153 struct bkey_cached *ck;
156 ck = bkey_cached_alloc(c);
159 ck = bkey_cached_reuse(c);
161 return ERR_PTR(-ENOMEM);
167 ck->c.btree_id = btree_id;
168 ck->key.btree_id = btree_id;
171 ck->flags = 1U << BKEY_CACHED_ACCESSED;
173 if (unlikely(rhashtable_lookup_insert_fast(&c->table,
175 bch2_btree_key_cache_params))) {
176 /* We raced with another fill: */
178 if (likely(was_new)) {
179 six_unlock_write(&ck->c.lock);
180 six_unlock_intent(&ck->c.lock);
183 mutex_lock(&c->lock);
184 bkey_cached_free(c, ck);
185 mutex_unlock(&c->lock);
191 atomic_long_inc(&c->nr_keys);
193 six_unlock_write(&ck->c.lock);
198 static int btree_key_cache_fill(struct btree_trans *trans,
199 struct btree_iter *ck_iter,
200 struct bkey_cached *ck)
202 struct btree_iter *iter;
204 unsigned new_u64s = 0;
205 struct bkey_i *new_k = NULL;
208 iter = bch2_trans_get_iter(trans, ck->key.btree_id,
209 ck->key.pos, BTREE_ITER_SLOTS);
210 k = bch2_btree_iter_peek_slot(iter);
215 if (!bch2_btree_node_relock(ck_iter, 0)) {
216 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
222 * bch2_varint_decode can read past the end of the buffer by at
223 * most 7 bytes (it won't be used):
225 new_u64s = k.k->u64s + 1;
227 if (new_u64s > ck->u64s) {
228 new_u64s = roundup_pow_of_two(new_u64s);
229 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOFS);
236 bch2_btree_node_lock_write(ck_iter->l[0].b, ck_iter);
243 bkey_reassemble(ck->k, k);
245 bch2_btree_node_unlock_write(ck_iter->l[0].b, ck_iter);
247 /* We're not likely to need this iterator again: */
248 set_btree_iter_dontneed(trans, iter);
250 bch2_trans_iter_put(trans, iter);
254 static int bkey_cached_check_fn(struct six_lock *lock, void *p)
256 struct bkey_cached *ck = container_of(lock, struct bkey_cached, c.lock);
257 const struct btree_iter *iter = p;
259 return ck->key.btree_id == iter->btree_id &&
260 !bpos_cmp(ck->key.pos, iter->pos) ? 0 : -1;
264 int bch2_btree_iter_traverse_cached(struct btree_iter *iter)
266 struct btree_trans *trans = iter->trans;
267 struct bch_fs *c = trans->c;
268 struct bkey_cached *ck;
273 if (btree_node_locked(iter, 0)) {
274 ck = (void *) iter->l[0].b;
278 ck = bch2_btree_key_cache_find(c, iter->btree_id, iter->pos);
280 if (iter->flags & BTREE_ITER_CACHED_NOCREATE) {
285 ck = btree_key_cache_create(&c->btree_key_cache,
286 iter->btree_id, iter->pos);
287 ret = PTR_ERR_OR_ZERO(ck);
293 mark_btree_node_locked(iter, 0, SIX_LOCK_intent);
294 iter->locks_want = 1;
296 enum six_lock_type lock_want = __btree_lock_want(iter, 0);
298 if (!btree_node_lock((void *) ck, iter->pos, 0, iter, lock_want,
299 bkey_cached_check_fn, iter, _THIS_IP_)) {
300 if (ck->key.btree_id != iter->btree_id ||
301 bpos_cmp(ck->key.pos, iter->pos)) {
305 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
310 if (ck->key.btree_id != iter->btree_id ||
311 bpos_cmp(ck->key.pos, iter->pos)) {
312 six_unlock_type(&ck->c.lock, lock_want);
316 mark_btree_node_locked(iter, 0, lock_want);
319 iter->l[0].lock_seq = ck->c.lock.state.seq;
320 iter->l[0].b = (void *) ck;
322 if (!ck->valid && !(iter->flags & BTREE_ITER_CACHED_NOFILL)) {
323 if (!btree_node_intent_locked(iter, 0))
324 bch2_btree_iter_upgrade(iter, 1);
325 if (!btree_node_intent_locked(iter, 0)) {
326 trace_transaction_restart_ip(trans->ip, _THIS_IP_);
331 ret = btree_key_cache_fill(trans, iter, ck);
336 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
337 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
339 iter->uptodate = BTREE_ITER_NEED_PEEK;
341 if (!(iter->flags & BTREE_ITER_INTENT))
342 bch2_btree_iter_downgrade(iter);
343 else if (!iter->locks_want) {
344 if (!__bch2_btree_iter_upgrade(iter, 1))
351 btree_node_unlock(iter, 0);
352 iter->flags |= BTREE_ITER_ERROR;
353 iter->l[0].b = BTREE_ITER_NO_NODE_ERROR;
358 static int btree_key_cache_flush_pos(struct btree_trans *trans,
359 struct bkey_cached_key key,
361 unsigned commit_flags,
364 struct bch_fs *c = trans->c;
365 struct journal *j = &c->journal;
366 struct btree_iter *c_iter = NULL, *b_iter = NULL;
367 struct bkey_cached *ck = NULL;
370 b_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
373 c_iter = bch2_trans_get_iter(trans, key.btree_id, key.pos,
375 BTREE_ITER_CACHED_NOFILL|
376 BTREE_ITER_CACHED_NOCREATE|
379 ret = bch2_btree_iter_traverse(c_iter);
383 ck = (void *) c_iter->l[0].b;
385 (journal_seq && ck->journal.seq != journal_seq))
388 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
395 * Since journal reclaim depends on us making progress here, and the
396 * allocator/copygc depend on journal reclaim making progress, we need
397 * to be using alloc reserves:
399 ret = bch2_btree_iter_traverse(b_iter) ?:
400 bch2_trans_update(trans, b_iter, ck->k, BTREE_TRIGGER_NORUN) ?:
401 bch2_trans_commit(trans, NULL, NULL,
402 BTREE_INSERT_NOUNLOCK|
403 BTREE_INSERT_NOCHECK_RW|
405 BTREE_INSERT_USE_RESERVE|
406 (ck->journal.seq == journal_last_seq(j)
407 ? BTREE_INSERT_JOURNAL_RESERVED
418 bch2_fs_fatal_err_on(!bch2_journal_error(j), c,
419 "error flushing key cache: %i", ret);
423 bch2_journal_pin_drop(j, &ck->journal);
424 bch2_journal_preres_put(j, &ck->res);
426 BUG_ON(!btree_node_locked(c_iter, 0));
429 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
430 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
431 atomic_long_dec(&c->btree_key_cache.nr_dirty);
435 BUG_ON(!btree_node_intent_locked(c_iter, 0));
437 mark_btree_node_unlocked(c_iter, 0);
438 c_iter->l[0].b = NULL;
440 six_lock_write(&ck->c.lock, NULL, NULL);
442 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
443 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
444 atomic_long_dec(&c->btree_key_cache.nr_dirty);
447 bkey_cached_evict(&c->btree_key_cache, ck);
449 mutex_lock(&c->btree_key_cache.lock);
450 bkey_cached_free(&c->btree_key_cache, ck);
451 mutex_unlock(&c->btree_key_cache.lock);
454 bch2_trans_iter_put(trans, b_iter);
455 bch2_trans_iter_put(trans, c_iter);
459 int bch2_btree_key_cache_journal_flush(struct journal *j,
460 struct journal_entry_pin *pin, u64 seq)
462 struct bch_fs *c = container_of(j, struct bch_fs, journal);
463 struct bkey_cached *ck =
464 container_of(pin, struct bkey_cached, journal);
465 struct bkey_cached_key key;
466 struct btree_trans trans;
469 int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
471 six_lock_read(&ck->c.lock, NULL, NULL);
474 if (ck->journal.seq != seq ||
475 !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
476 six_unlock_read(&ck->c.lock);
479 six_unlock_read(&ck->c.lock);
481 bch2_trans_init(&trans, c, 0, 0);
482 ret = btree_key_cache_flush_pos(&trans, key, seq,
483 BTREE_INSERT_JOURNAL_RECLAIM, false);
484 bch2_trans_exit(&trans);
486 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
492 * Flush and evict a key from the key cache:
494 int bch2_btree_key_cache_flush(struct btree_trans *trans,
495 enum btree_id id, struct bpos pos)
497 struct bch_fs *c = trans->c;
498 struct bkey_cached_key key = { id, pos };
500 /* Fastpath - assume it won't be found: */
501 if (!bch2_btree_key_cache_find(c, id, pos))
504 return btree_key_cache_flush_pos(trans, key, 0, 0, true);
507 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
508 struct btree_iter *iter,
509 struct bkey_i *insert)
511 struct bch_fs *c = trans->c;
512 struct bkey_cached *ck = (void *) iter->l[0].b;
513 bool kick_reclaim = false;
515 BUG_ON(insert->u64s > ck->u64s);
517 if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
520 BUG_ON(jset_u64s(insert->u64s) > trans->journal_preres.u64s);
522 difference = jset_u64s(insert->u64s) - ck->res.u64s;
523 if (difference > 0) {
524 trans->journal_preres.u64s -= difference;
525 ck->res.u64s += difference;
529 bkey_copy(ck->k, insert);
532 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
533 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
534 atomic_long_inc(&c->btree_key_cache.nr_dirty);
536 if (bch2_nr_btree_keys_need_flush(c))
540 bch2_journal_pin_update(&c->journal, trans->journal_res.seq,
541 &ck->journal, bch2_btree_key_cache_journal_flush);
544 journal_reclaim_kick(&c->journal);
548 #ifdef CONFIG_BCACHEFS_DEBUG
549 void bch2_btree_key_cache_verify_clean(struct btree_trans *trans,
550 enum btree_id id, struct bpos pos)
552 BUG_ON(bch2_btree_key_cache_find(trans->c, id, pos));
556 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
557 struct shrink_control *sc)
559 struct bch_fs *c = container_of(shrink, struct bch_fs,
560 btree_key_cache.shrink);
561 struct btree_key_cache *bc = &c->btree_key_cache;
562 struct bucket_table *tbl;
563 struct bkey_cached *ck, *t;
564 size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
565 unsigned start, flags;
568 /* Return -1 if we can't do anything right now */
569 if (sc->gfp_mask & __GFP_FS)
570 mutex_lock(&bc->lock);
571 else if (!mutex_trylock(&bc->lock))
574 srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
575 flags = memalloc_nofs_save();
578 * Newest freed entries are at the end of the list - once we hit one
579 * that's too new to be freed, we can bail out:
581 list_for_each_entry_safe(ck, t, &bc->freed, list) {
582 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
583 ck->btree_trans_barrier_seq))
587 kmem_cache_free(bch2_key_cache, ck);
597 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
598 if (bc->shrink_iter >= tbl->size)
600 start = bc->shrink_iter;
603 struct rhash_head *pos, *next;
605 pos = rht_ptr_rcu(rht_bucket(tbl, bc->shrink_iter));
607 while (!rht_is_a_nulls(pos)) {
608 next = rht_dereference_bucket_rcu(pos->next, tbl, bc->shrink_iter);
609 ck = container_of(pos, struct bkey_cached, hash);
611 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags))
614 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
615 clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
616 else if (bkey_cached_lock_for_evict(ck)) {
617 bkey_cached_evict(bc, ck);
618 bkey_cached_free(bc, ck);
629 if (bc->shrink_iter >= tbl->size)
631 } while (scanned < nr && bc->shrink_iter != start);
635 memalloc_nofs_restore(flags);
636 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
637 mutex_unlock(&bc->lock);
642 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
643 struct shrink_control *sc)
645 struct bch_fs *c = container_of(shrink, struct bch_fs,
646 btree_key_cache.shrink);
647 struct btree_key_cache *bc = &c->btree_key_cache;
649 return atomic_long_read(&bc->nr_keys);
652 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
654 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
655 struct bucket_table *tbl;
656 struct bkey_cached *ck, *n;
657 struct rhash_head *pos;
660 if (bc->shrink.list.next)
661 unregister_shrinker(&bc->shrink);
663 mutex_lock(&bc->lock);
666 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
667 for (i = 0; i < tbl->size; i++)
668 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
669 bkey_cached_evict(bc, ck);
670 list_add(&ck->list, &bc->freed);
674 list_for_each_entry_safe(ck, n, &bc->freed, list) {
677 bch2_journal_pin_drop(&c->journal, &ck->journal);
678 bch2_journal_preres_put(&c->journal, &ck->res);
682 kmem_cache_free(bch2_key_cache, ck);
685 BUG_ON(atomic_long_read(&bc->nr_dirty) && !bch2_journal_error(&c->journal));
686 BUG_ON(atomic_long_read(&bc->nr_keys));
688 mutex_unlock(&bc->lock);
690 if (bc->table_init_done)
691 rhashtable_destroy(&bc->table);
694 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
696 mutex_init(&c->lock);
697 INIT_LIST_HEAD(&c->freed);
700 int bch2_fs_btree_key_cache_init(struct btree_key_cache *c)
704 ret = rhashtable_init(&c->table, &bch2_btree_key_cache_params);
708 c->table_init_done = true;
711 c->shrink.count_objects = bch2_btree_key_cache_count;
712 c->shrink.scan_objects = bch2_btree_key_cache_scan;
713 return register_shrinker(&c->shrink);
716 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
718 pr_buf(out, "nr_freed:\t%zu\n", c->nr_freed);
719 pr_buf(out, "nr_keys:\t%zu\n", atomic_long_read(&c->nr_keys));
720 pr_buf(out, "nr_dirty:\t%zu\n", atomic_long_read(&c->nr_dirty));
723 void bch2_btree_key_cache_exit(void)
726 kmem_cache_destroy(bch2_key_cache);
729 int __init bch2_btree_key_cache_init(void)
731 bch2_key_cache = KMEM_CACHE(bkey_cached, 0);