1 // SPDX-License-Identifier: GPL-2.0
4 #include "btree_cache.h"
5 #include "btree_iter.h"
6 #include "btree_key_cache.h"
7 #include "btree_locking.h"
8 #include "btree_update.h"
12 #include "journal_reclaim.h"
15 #include <linux/sched/mm.h>
16 #include <linux/seq_buf.h>
18 static inline bool btree_uses_pcpu_readers(enum btree_id id)
20 return id == BTREE_ID_subvolumes;
23 static struct kmem_cache *bch2_key_cache;
25 static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
28 const struct bkey_cached *ck = obj;
29 const struct bkey_cached_key *key = arg->key;
31 return ck->key.btree_id != key->btree_id ||
32 !bpos_eq(ck->key.pos, key->pos);
35 static const struct rhashtable_params bch2_btree_key_cache_params = {
36 .head_offset = offsetof(struct bkey_cached, hash),
37 .key_offset = offsetof(struct bkey_cached, key),
38 .key_len = sizeof(struct bkey_cached_key),
39 .obj_cmpfn = bch2_btree_key_cache_cmp_fn,
43 inline struct bkey_cached *
44 bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
46 struct bkey_cached_key key = {
51 return rhashtable_lookup_fast(&c->btree_key_cache.table, &key,
52 bch2_btree_key_cache_params);
55 static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
57 if (!six_trylock_intent(&ck->c.lock))
60 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
61 six_unlock_intent(&ck->c.lock);
65 if (!six_trylock_write(&ck->c.lock)) {
66 six_unlock_intent(&ck->c.lock);
73 static void bkey_cached_evict(struct btree_key_cache *c,
74 struct bkey_cached *ck)
76 BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
77 bch2_btree_key_cache_params));
78 memset(&ck->key, ~0, sizeof(ck->key));
80 atomic_long_dec(&c->nr_keys);
83 static void bkey_cached_free(struct btree_key_cache *bc,
84 struct bkey_cached *ck)
86 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
88 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
90 ck->btree_trans_barrier_seq =
91 start_poll_synchronize_srcu(&c->btree_trans_barrier);
93 if (ck->c.lock.readers)
94 list_move_tail(&ck->list, &bc->freed_pcpu);
96 list_move_tail(&ck->list, &bc->freed_nonpcpu);
97 atomic_long_inc(&bc->nr_freed);
103 six_unlock_write(&ck->c.lock);
104 six_unlock_intent(&ck->c.lock);
108 static void __bkey_cached_move_to_freelist_ordered(struct btree_key_cache *bc,
109 struct bkey_cached *ck)
111 struct bkey_cached *pos;
113 list_for_each_entry_reverse(pos, &bc->freed_nonpcpu, list) {
114 if (ULONG_CMP_GE(ck->btree_trans_barrier_seq,
115 pos->btree_trans_barrier_seq)) {
116 list_move(&ck->list, &pos->list);
121 list_move(&ck->list, &bc->freed_nonpcpu);
125 static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
126 struct bkey_cached *ck)
128 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
130 if (!ck->c.lock.readers) {
132 struct btree_key_cache_freelist *f;
136 f = this_cpu_ptr(bc->pcpu_freed);
138 if (f->nr < ARRAY_SIZE(f->objs)) {
139 f->objs[f->nr++] = ck;
145 mutex_lock(&bc->lock);
147 f = this_cpu_ptr(bc->pcpu_freed);
149 while (f->nr > ARRAY_SIZE(f->objs) / 2) {
150 struct bkey_cached *ck2 = f->objs[--f->nr];
152 __bkey_cached_move_to_freelist_ordered(bc, ck2);
156 __bkey_cached_move_to_freelist_ordered(bc, ck);
157 mutex_unlock(&bc->lock);
160 mutex_lock(&bc->lock);
161 list_move_tail(&ck->list, &bc->freed_nonpcpu);
162 mutex_unlock(&bc->lock);
165 mutex_lock(&bc->lock);
166 list_move_tail(&ck->list, &bc->freed_pcpu);
167 mutex_unlock(&bc->lock);
171 static void bkey_cached_free_fast(struct btree_key_cache *bc,
172 struct bkey_cached *ck)
174 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
176 ck->btree_trans_barrier_seq =
177 start_poll_synchronize_srcu(&c->btree_trans_barrier);
179 list_del_init(&ck->list);
180 atomic_long_inc(&bc->nr_freed);
186 bkey_cached_move_to_freelist(bc, ck);
188 six_unlock_write(&ck->c.lock);
189 six_unlock_intent(&ck->c.lock);
192 static struct bkey_cached *
193 bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
196 struct bch_fs *c = trans->c;
197 struct btree_key_cache *bc = &c->btree_key_cache;
198 struct bkey_cached *ck = NULL;
199 bool pcpu_readers = btree_uses_pcpu_readers(path->btree_id);
204 struct btree_key_cache_freelist *f;
207 f = this_cpu_ptr(bc->pcpu_freed);
209 ck = f->objs[--f->nr];
213 mutex_lock(&bc->lock);
215 f = this_cpu_ptr(bc->pcpu_freed);
217 while (!list_empty(&bc->freed_nonpcpu) &&
218 f->nr < ARRAY_SIZE(f->objs) / 2) {
219 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
220 list_del_init(&ck->list);
221 f->objs[f->nr++] = ck;
224 ck = f->nr ? f->objs[--f->nr] : NULL;
226 mutex_unlock(&bc->lock);
229 mutex_lock(&bc->lock);
230 if (!list_empty(&bc->freed_nonpcpu)) {
231 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
232 list_del_init(&ck->list);
234 mutex_unlock(&bc->lock);
237 mutex_lock(&bc->lock);
238 if (!list_empty(&bc->freed_pcpu)) {
239 ck = list_last_entry(&bc->freed_pcpu, struct bkey_cached, list);
240 list_del_init(&ck->list);
242 mutex_unlock(&bc->lock);
248 ret = btree_node_lock_nopath(trans, &ck->c, SIX_LOCK_intent, _THIS_IP_);
250 bkey_cached_move_to_freelist(bc, ck);
254 path->l[0].b = (void *) ck;
255 path->l[0].lock_seq = ck->c.lock.state.seq;
256 mark_btree_node_locked(trans, path, 0, SIX_LOCK_intent);
258 ret = bch2_btree_node_lock_write(trans, path, &ck->c);
260 btree_node_unlock(trans, path, 0);
261 bkey_cached_move_to_freelist(bc, ck);
268 ck = kmem_cache_zalloc(bch2_key_cache, GFP_NOWAIT|__GFP_NOWARN);
272 bch2_trans_unlock(trans);
274 ck = kmem_cache_zalloc(bch2_key_cache, GFP_KERNEL);
276 ret = bch2_trans_relock(trans);
278 kmem_cache_free(bch2_key_cache, ck);
285 INIT_LIST_HEAD(&ck->list);
286 bch2_btree_lock_init(&ck->c);
288 six_lock_pcpu_alloc(&ck->c.lock);
291 BUG_ON(!six_trylock_intent(&ck->c.lock));
292 BUG_ON(!six_trylock_write(&ck->c.lock));
297 static struct bkey_cached *
298 bkey_cached_reuse(struct btree_key_cache *c)
300 struct bucket_table *tbl;
301 struct rhash_head *pos;
302 struct bkey_cached *ck;
305 mutex_lock(&c->lock);
307 tbl = rht_dereference_rcu(c->table.tbl, &c->table);
308 for (i = 0; i < tbl->size; i++)
309 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
310 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
311 bkey_cached_lock_for_evict(ck)) {
312 bkey_cached_evict(c, ck);
319 mutex_unlock(&c->lock);
323 static struct bkey_cached *
324 btree_key_cache_create(struct btree_trans *trans, struct btree_path *path)
326 struct bch_fs *c = trans->c;
327 struct btree_key_cache *bc = &c->btree_key_cache;
328 struct bkey_cached *ck;
329 bool was_new = false;
331 ck = bkey_cached_alloc(trans, path, &was_new);
336 ck = bkey_cached_reuse(bc);
338 bch_err(c, "error allocating memory for key cache item, btree %s",
339 bch2_btree_ids[path->btree_id]);
340 return ERR_PTR(-BCH_ERR_ENOMEM_btree_key_cache_create);
343 mark_btree_node_locked(trans, path, 0, SIX_LOCK_intent);
345 if (path->btree_id == BTREE_ID_subvolumes)
346 six_lock_pcpu_alloc(&ck->c.lock);
350 ck->c.btree_id = path->btree_id;
351 ck->key.btree_id = path->btree_id;
352 ck->key.pos = path->pos;
354 ck->flags = 1U << BKEY_CACHED_ACCESSED;
356 if (unlikely(rhashtable_lookup_insert_fast(&bc->table,
358 bch2_btree_key_cache_params))) {
359 /* We raced with another fill: */
361 if (likely(was_new)) {
362 six_unlock_write(&ck->c.lock);
363 six_unlock_intent(&ck->c.lock);
366 bkey_cached_free_fast(bc, ck);
369 mark_btree_node_locked(trans, path, 0, BTREE_NODE_UNLOCKED);
373 atomic_long_inc(&bc->nr_keys);
375 six_unlock_write(&ck->c.lock);
380 static int btree_key_cache_fill(struct btree_trans *trans,
381 struct btree_path *ck_path,
382 struct bkey_cached *ck)
384 struct btree_iter iter;
386 unsigned new_u64s = 0;
387 struct bkey_i *new_k = NULL;
390 k = bch2_bkey_get_iter(trans, &iter, ck->key.btree_id, ck->key.pos,
391 BTREE_ITER_KEY_CACHE_FILL|
392 BTREE_ITER_CACHED_NOFILL);
397 if (!bch2_btree_node_relock(trans, ck_path, 0)) {
398 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
399 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
404 * bch2_varint_decode can read past the end of the buffer by at
405 * most 7 bytes (it won't be used):
407 new_u64s = k.k->u64s + 1;
410 * Allocate some extra space so that the transaction commit path is less
411 * likely to have to reallocate, since that requires a transaction
414 new_u64s = min(256U, (new_u64s * 3) / 2);
416 if (new_u64s > ck->u64s) {
417 new_u64s = roundup_pow_of_two(new_u64s);
418 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOWAIT|__GFP_NOWARN);
420 bch2_trans_unlock(trans);
422 new_k = kmalloc(new_u64s * sizeof(u64), GFP_KERNEL);
424 bch_err(trans->c, "error allocating memory for key cache key, btree %s u64s %u",
425 bch2_btree_ids[ck->key.btree_id], new_u64s);
426 ret = -BCH_ERR_ENOMEM_btree_key_cache_fill;
430 if (!bch2_btree_node_relock(trans, ck_path, 0)) {
432 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
433 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
437 ret = bch2_trans_relock(trans);
445 ret = bch2_btree_node_lock_write(trans, ck_path, &ck_path->l[0].b->c);
457 bkey_reassemble(ck->k, k);
459 bch2_btree_node_unlock_write(trans, ck_path, ck_path->l[0].b);
461 /* We're not likely to need this iterator again: */
462 set_btree_iter_dontneed(&iter);
464 bch2_trans_iter_exit(trans, &iter);
469 bch2_btree_path_traverse_cached_slowpath(struct btree_trans *trans, struct btree_path *path,
472 struct bch_fs *c = trans->c;
473 struct bkey_cached *ck;
480 if (bch2_btree_node_relock_notrace(trans, path, 0)) {
481 ck = (void *) path->l[0].b;
485 ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
487 ck = btree_key_cache_create(trans, path);
488 ret = PTR_ERR_OR_ZERO(ck);
494 mark_btree_node_locked(trans, path, 0, SIX_LOCK_intent);
495 path->locks_want = 1;
497 enum six_lock_type lock_want = __btree_lock_want(path, 0);
499 ret = btree_node_lock(trans, path, (void *) ck, 0,
500 lock_want, _THIS_IP_);
501 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
506 if (ck->key.btree_id != path->btree_id ||
507 !bpos_eq(ck->key.pos, path->pos)) {
508 six_unlock_type(&ck->c.lock, lock_want);
512 mark_btree_node_locked(trans, path, 0, lock_want);
515 path->l[0].lock_seq = ck->c.lock.state.seq;
516 path->l[0].b = (void *) ck;
518 path->uptodate = BTREE_ITER_UPTODATE;
520 if (!ck->valid && !(flags & BTREE_ITER_CACHED_NOFILL)) {
522 * Using the underscore version because we haven't set
523 * path->uptodate yet:
525 if (!path->locks_want &&
526 !__bch2_btree_path_upgrade(trans, path, 1)) {
527 trace_and_count(trans->c, trans_restart_key_cache_upgrade, trans, _THIS_IP_);
528 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_upgrade);
532 ret = btree_key_cache_fill(trans, path, ck);
536 ret = bch2_btree_path_relock(trans, path, _THIS_IP_);
540 path->uptodate = BTREE_ITER_UPTODATE;
543 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
544 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
546 BUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
547 BUG_ON(path->uptodate);
551 path->uptodate = BTREE_ITER_NEED_TRAVERSE;
552 if (!bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
553 btree_node_unlock(trans, path, 0);
554 path->l[0].b = ERR_PTR(ret);
559 int bch2_btree_path_traverse_cached(struct btree_trans *trans, struct btree_path *path,
562 struct bch_fs *c = trans->c;
563 struct bkey_cached *ck;
566 EBUG_ON(path->level);
570 if (bch2_btree_node_relock_notrace(trans, path, 0)) {
571 ck = (void *) path->l[0].b;
575 ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
577 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
579 enum six_lock_type lock_want = __btree_lock_want(path, 0);
581 ret = btree_node_lock(trans, path, (void *) ck, 0,
582 lock_want, _THIS_IP_);
583 EBUG_ON(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart));
588 if (ck->key.btree_id != path->btree_id ||
589 !bpos_eq(ck->key.pos, path->pos)) {
590 six_unlock_type(&ck->c.lock, lock_want);
594 mark_btree_node_locked(trans, path, 0, lock_want);
597 path->l[0].lock_seq = ck->c.lock.state.seq;
598 path->l[0].b = (void *) ck;
601 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
603 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
604 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
606 path->uptodate = BTREE_ITER_UPTODATE;
608 EBUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
613 static int btree_key_cache_flush_pos(struct btree_trans *trans,
614 struct bkey_cached_key key,
616 unsigned commit_flags,
619 struct bch_fs *c = trans->c;
620 struct journal *j = &c->journal;
621 struct btree_iter c_iter, b_iter;
622 struct bkey_cached *ck = NULL;
625 bch2_trans_iter_init(trans, &b_iter, key.btree_id, key.pos,
628 BTREE_ITER_ALL_SNAPSHOTS);
629 bch2_trans_iter_init(trans, &c_iter, key.btree_id, key.pos,
632 b_iter.flags &= ~BTREE_ITER_WITH_KEY_CACHE;
634 ret = bch2_btree_iter_traverse(&c_iter);
638 ck = (void *) c_iter.path->l[0].b;
642 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
650 if (journal_seq && ck->journal.seq != journal_seq)
654 * Since journal reclaim depends on us making progress here, and the
655 * allocator/copygc depend on journal reclaim making progress, we need
656 * to be using alloc reserves:
658 ret = bch2_btree_iter_traverse(&b_iter) ?:
659 bch2_trans_update(trans, &b_iter, ck->k,
660 BTREE_UPDATE_KEY_CACHE_RECLAIM|
661 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
662 BTREE_TRIGGER_NORUN) ?:
663 bch2_trans_commit(trans, NULL, NULL,
664 BTREE_INSERT_NOCHECK_RW|
666 BTREE_INSERT_USE_RESERVE|
667 (ck->journal.seq == journal_last_seq(j)
668 ? JOURNAL_WATERMARK_reserved
672 bch2_fs_fatal_err_on(ret &&
673 !bch2_err_matches(ret, BCH_ERR_transaction_restart) &&
674 !bch2_err_matches(ret, BCH_ERR_journal_reclaim_would_deadlock) &&
675 !bch2_journal_error(j), c,
676 "error flushing key cache: %s", bch2_err_str(ret));
680 bch2_journal_pin_drop(j, &ck->journal);
681 bch2_journal_preres_put(j, &ck->res);
683 BUG_ON(!btree_node_locked(c_iter.path, 0));
686 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
687 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
688 atomic_long_dec(&c->btree_key_cache.nr_dirty);
691 struct btree_path *path2;
693 trans_for_each_path(trans, path2)
694 if (path2 != c_iter.path)
695 __bch2_btree_path_unlock(trans, path2);
697 bch2_btree_node_lock_write_nofail(trans, c_iter.path, &ck->c);
699 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
700 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
701 atomic_long_dec(&c->btree_key_cache.nr_dirty);
704 mark_btree_node_locked_noreset(c_iter.path, 0, BTREE_NODE_UNLOCKED);
705 bkey_cached_evict(&c->btree_key_cache, ck);
706 bkey_cached_free_fast(&c->btree_key_cache, ck);
709 bch2_trans_iter_exit(trans, &b_iter);
710 bch2_trans_iter_exit(trans, &c_iter);
714 int bch2_btree_key_cache_journal_flush(struct journal *j,
715 struct journal_entry_pin *pin, u64 seq)
717 struct bch_fs *c = container_of(j, struct bch_fs, journal);
718 struct bkey_cached *ck =
719 container_of(pin, struct bkey_cached, journal);
720 struct bkey_cached_key key;
721 struct btree_trans trans;
722 int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
725 bch2_trans_init(&trans, c, 0, 0);
727 btree_node_lock_nopath_nofail(&trans, &ck->c, SIX_LOCK_read);
730 if (ck->journal.seq != seq ||
731 !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
732 six_unlock_read(&ck->c.lock);
736 if (ck->seq != seq) {
737 bch2_journal_pin_update(&c->journal, ck->seq, &ck->journal,
738 bch2_btree_key_cache_journal_flush);
739 six_unlock_read(&ck->c.lock);
742 six_unlock_read(&ck->c.lock);
744 ret = commit_do(&trans, NULL, NULL, 0,
745 btree_key_cache_flush_pos(&trans, key, seq,
746 BTREE_INSERT_JOURNAL_RECLAIM, false));
748 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
750 bch2_trans_exit(&trans);
755 * Flush and evict a key from the key cache:
757 int bch2_btree_key_cache_flush(struct btree_trans *trans,
758 enum btree_id id, struct bpos pos)
760 struct bch_fs *c = trans->c;
761 struct bkey_cached_key key = { id, pos };
763 /* Fastpath - assume it won't be found: */
764 if (!bch2_btree_key_cache_find(c, id, pos))
767 return btree_key_cache_flush_pos(trans, key, 0, 0, true);
770 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
772 struct btree_insert_entry *insert_entry)
774 struct bch_fs *c = trans->c;
775 struct bkey_cached *ck = (void *) insert_entry->path->l[0].b;
776 struct bkey_i *insert = insert_entry->k;
777 bool kick_reclaim = false;
779 BUG_ON(insert->k.u64s > ck->u64s);
781 if (likely(!(flags & BTREE_INSERT_JOURNAL_REPLAY))) {
784 BUG_ON(jset_u64s(insert->k.u64s) > trans->journal_preres.u64s);
786 difference = jset_u64s(insert->k.u64s) - ck->res.u64s;
787 if (difference > 0) {
788 trans->journal_preres.u64s -= difference;
789 ck->res.u64s += difference;
793 bkey_copy(ck->k, insert);
796 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
797 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
798 atomic_long_inc(&c->btree_key_cache.nr_dirty);
800 if (bch2_nr_btree_keys_need_flush(c))
805 * To minimize lock contention, we only add the journal pin here and
806 * defer pin updates to the flush callback via ->seq. Be careful not to
807 * update ->seq on nojournal commits because we don't want to update the
808 * pin to a seq that doesn't include journal updates on disk. Otherwise
809 * we risk losing the update after a crash.
811 * The only exception is if the pin is not active in the first place. We
812 * have to add the pin because journal reclaim drives key cache
813 * flushing. The flush callback will not proceed unless ->seq matches
814 * the latest pin, so make sure it starts with a consistent value.
816 if (!(insert_entry->flags & BTREE_UPDATE_NOJOURNAL) ||
817 !journal_pin_active(&ck->journal)) {
818 ck->seq = trans->journal_res.seq;
820 bch2_journal_pin_add(&c->journal, trans->journal_res.seq,
821 &ck->journal, bch2_btree_key_cache_journal_flush);
824 journal_reclaim_kick(&c->journal);
828 void bch2_btree_key_cache_drop(struct btree_trans *trans,
829 struct btree_path *path)
831 struct bch_fs *c = trans->c;
832 struct bkey_cached *ck = (void *) path->l[0].b;
837 * We just did an update to the btree, bypassing the key cache: the key
838 * cache key is now stale and must be dropped, even if dirty:
840 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
841 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
842 atomic_long_dec(&c->btree_key_cache.nr_dirty);
843 bch2_journal_pin_drop(&c->journal, &ck->journal);
849 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
850 struct shrink_control *sc)
852 struct bch_fs *c = container_of(shrink, struct bch_fs,
853 btree_key_cache.shrink);
854 struct btree_key_cache *bc = &c->btree_key_cache;
855 struct bucket_table *tbl;
856 struct bkey_cached *ck, *t;
857 size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
858 unsigned start, flags;
861 mutex_lock(&bc->lock);
862 srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
863 flags = memalloc_nofs_save();
866 * Newest freed entries are at the end of the list - once we hit one
867 * that's too new to be freed, we can bail out:
869 list_for_each_entry_safe(ck, t, &bc->freed_nonpcpu, list) {
870 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
871 ck->btree_trans_barrier_seq))
875 six_lock_pcpu_free(&ck->c.lock);
876 kmem_cache_free(bch2_key_cache, ck);
877 atomic_long_dec(&bc->nr_freed);
885 list_for_each_entry_safe(ck, t, &bc->freed_pcpu, list) {
886 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
887 ck->btree_trans_barrier_seq))
891 six_lock_pcpu_free(&ck->c.lock);
892 kmem_cache_free(bch2_key_cache, ck);
893 atomic_long_dec(&bc->nr_freed);
902 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
903 if (bc->shrink_iter >= tbl->size)
905 start = bc->shrink_iter;
908 struct rhash_head *pos, *next;
910 pos = rht_ptr_rcu(rht_bucket(tbl, bc->shrink_iter));
912 while (!rht_is_a_nulls(pos)) {
913 next = rht_dereference_bucket_rcu(pos->next, tbl, bc->shrink_iter);
914 ck = container_of(pos, struct bkey_cached, hash);
916 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags))
919 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
920 clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
921 else if (bkey_cached_lock_for_evict(ck)) {
922 bkey_cached_evict(bc, ck);
923 bkey_cached_free(bc, ck);
934 if (bc->shrink_iter >= tbl->size)
936 } while (scanned < nr && bc->shrink_iter != start);
940 memalloc_nofs_restore(flags);
941 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
942 mutex_unlock(&bc->lock);
947 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
948 struct shrink_control *sc)
950 struct bch_fs *c = container_of(shrink, struct bch_fs,
951 btree_key_cache.shrink);
952 struct btree_key_cache *bc = &c->btree_key_cache;
953 long nr = atomic_long_read(&bc->nr_keys) -
954 atomic_long_read(&bc->nr_dirty);
959 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
961 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
962 struct bucket_table *tbl;
963 struct bkey_cached *ck, *n;
964 struct rhash_head *pos;
971 if (bc->shrink.list.next)
972 unregister_shrinker(&bc->shrink);
974 mutex_lock(&bc->lock);
977 * The loop is needed to guard against racing with rehash:
979 while (atomic_long_read(&bc->nr_keys)) {
981 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
983 for (i = 0; i < tbl->size; i++)
984 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
985 bkey_cached_evict(bc, ck);
986 list_add(&ck->list, &items);
992 for_each_possible_cpu(cpu) {
993 struct btree_key_cache_freelist *f =
994 per_cpu_ptr(bc->pcpu_freed, cpu);
996 for (i = 0; i < f->nr; i++) {
998 list_add(&ck->list, &items);
1003 list_splice(&bc->freed_pcpu, &items);
1004 list_splice(&bc->freed_nonpcpu, &items);
1006 mutex_unlock(&bc->lock);
1008 list_for_each_entry_safe(ck, n, &items, list) {
1011 bch2_journal_pin_drop(&c->journal, &ck->journal);
1012 bch2_journal_preres_put(&c->journal, &ck->res);
1014 list_del(&ck->list);
1016 six_lock_pcpu_free(&ck->c.lock);
1017 kmem_cache_free(bch2_key_cache, ck);
1020 if (atomic_long_read(&bc->nr_dirty) &&
1021 !bch2_journal_error(&c->journal) &&
1022 test_bit(BCH_FS_WAS_RW, &c->flags))
1023 panic("btree key cache shutdown error: nr_dirty nonzero (%li)\n",
1024 atomic_long_read(&bc->nr_dirty));
1026 if (atomic_long_read(&bc->nr_keys))
1027 panic("btree key cache shutdown error: nr_keys nonzero (%li)\n",
1028 atomic_long_read(&bc->nr_keys));
1030 if (bc->table_init_done)
1031 rhashtable_destroy(&bc->table);
1033 free_percpu(bc->pcpu_freed);
1036 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
1038 mutex_init(&c->lock);
1039 INIT_LIST_HEAD(&c->freed_pcpu);
1040 INIT_LIST_HEAD(&c->freed_nonpcpu);
1043 static void bch2_btree_key_cache_shrinker_to_text(struct seq_buf *s, struct shrinker *shrink)
1045 struct btree_key_cache *bc =
1046 container_of(shrink, struct btree_key_cache, shrink);
1048 size_t buflen = seq_buf_get_buf(s, &cbuf);
1049 struct printbuf out = PRINTBUF_EXTERN(cbuf, buflen);
1051 bch2_btree_key_cache_to_text(&out, bc);
1052 seq_buf_commit(s, out.pos);
1055 int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
1057 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
1060 bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
1061 if (!bc->pcpu_freed)
1062 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1065 if (rhashtable_init(&bc->table, &bch2_btree_key_cache_params))
1066 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1068 bc->table_init_done = true;
1070 bc->shrink.seeks = 0;
1071 bc->shrink.count_objects = bch2_btree_key_cache_count;
1072 bc->shrink.scan_objects = bch2_btree_key_cache_scan;
1073 bc->shrink.to_text = bch2_btree_key_cache_shrinker_to_text;
1074 if (register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name))
1075 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1079 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
1081 prt_printf(out, "nr_freed:\t%zu", atomic_long_read(&c->nr_freed));
1083 prt_printf(out, "nr_keys:\t%lu", atomic_long_read(&c->nr_keys));
1085 prt_printf(out, "nr_dirty:\t%lu", atomic_long_read(&c->nr_dirty));
1089 void bch2_btree_key_cache_exit(void)
1091 kmem_cache_destroy(bch2_key_cache);
1094 int __init bch2_btree_key_cache_init(void)
1096 bch2_key_cache = KMEM_CACHE(bkey_cached, 0);
1097 if (!bch2_key_cache)