3 #include "btree_cache.h"
5 #include "btree_iter.h"
6 #include "btree_locking.h"
9 #include <linux/prefetch.h>
10 #include <trace/events/bcachefs.h>
12 const char * const bch2_btree_ids[] = {
13 #define x(kwd, val, name) name,
19 void bch2_recalc_btree_reserve(struct bch_fs *c)
21 unsigned i, reserve = 16;
23 if (!c->btree_roots[0].b)
26 for (i = 0; i < BTREE_ID_NR; i++)
27 if (c->btree_roots[i].b)
28 reserve += min_t(unsigned, 1,
29 c->btree_roots[i].b->level) * 8;
31 c->btree_cache.reserve = reserve;
34 static inline unsigned btree_cache_can_free(struct btree_cache *bc)
36 return max_t(int, 0, bc->used - bc->reserve);
39 static void __btree_node_data_free(struct bch_fs *c, struct btree *b)
41 EBUG_ON(btree_node_write_in_flight(b));
43 kvpfree(b->data, btree_bytes(c));
45 bch2_btree_keys_free(b);
48 static void btree_node_data_free(struct bch_fs *c, struct btree *b)
50 struct btree_cache *bc = &c->btree_cache;
52 __btree_node_data_free(c, b);
54 list_move(&b->list, &bc->freed);
57 static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg,
60 const struct btree *b = obj;
61 const u64 *v = arg->key;
63 return PTR_HASH(&b->key) == *v ? 0 : 1;
66 static const struct rhashtable_params bch_btree_cache_params = {
67 .head_offset = offsetof(struct btree, hash),
68 .key_offset = offsetof(struct btree, key.v),
69 .key_len = sizeof(struct bch_extent_ptr),
70 .obj_cmpfn = bch2_btree_cache_cmp_fn,
73 static void btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
75 struct btree_cache *bc = &c->btree_cache;
77 b->data = kvpmalloc(btree_bytes(c), gfp);
81 if (bch2_btree_keys_alloc(b, btree_page_order(c), gfp))
85 list_move(&b->list, &bc->freeable);
88 kvpfree(b->data, btree_bytes(c));
90 list_move(&b->list, &bc->freed);
93 static struct btree *btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
95 struct btree *b = kzalloc(sizeof(struct btree), gfp);
99 bkey_btree_ptr_init(&b->key);
100 six_lock_init(&b->lock);
101 INIT_LIST_HEAD(&b->list);
102 INIT_LIST_HEAD(&b->write_blocked);
104 btree_node_data_alloc(c, b, gfp);
105 return b->data ? b : NULL;
108 /* Btree in memory cache - hash table */
110 void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b)
112 rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params);
114 /* Cause future lookups for this node to fail: */
115 PTR_HASH(&b->key) = 0;
118 int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b)
120 return rhashtable_lookup_insert_fast(&bc->table, &b->hash,
121 bch_btree_cache_params);
124 int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b,
125 unsigned level, enum btree_id id)
132 mutex_lock(&bc->lock);
133 ret = __bch2_btree_node_hash_insert(bc, b);
135 list_add(&b->list, &bc->live);
136 mutex_unlock(&bc->lock);
142 static inline struct btree *btree_cache_find(struct btree_cache *bc,
143 const struct bkey_i *k)
145 return rhashtable_lookup_fast(&bc->table, &PTR_HASH(k),
146 bch_btree_cache_params);
150 * this version is for btree nodes that have already been freed (we're not
151 * reaping a real btree node)
153 static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush)
155 struct btree_cache *bc = &c->btree_cache;
158 lockdep_assert_held(&bc->lock);
160 if (!six_trylock_intent(&b->lock))
163 if (!six_trylock_write(&b->lock))
164 goto out_unlock_intent;
166 if (btree_node_noevict(b))
169 if (!btree_node_may_write(b))
172 if (btree_node_dirty(b) &&
173 test_bit(BCH_FS_HOLD_BTREE_WRITES, &c->flags))
176 if (btree_node_dirty(b) ||
177 btree_node_write_in_flight(b) ||
178 btree_node_read_in_flight(b)) {
182 wait_on_bit_io(&b->flags, BTREE_NODE_read_in_flight,
183 TASK_UNINTERRUPTIBLE);
186 * Using the underscore version because we don't want to compact
187 * bsets after the write, since this node is about to be evicted
188 * - unless btree verify mode is enabled, since it runs out of
189 * the post write cleanup:
191 if (verify_btree_ondisk(c))
192 bch2_btree_node_write(c, b, SIX_LOCK_intent);
194 __bch2_btree_node_write(c, b, SIX_LOCK_read);
196 /* wait for any in flight btree write */
197 btree_node_wait_on_io(b);
200 if (PTR_HASH(&b->key) && !ret)
201 trace_btree_node_reap(c, b);
204 six_unlock_write(&b->lock);
206 six_unlock_intent(&b->lock);
211 static int btree_node_reclaim(struct bch_fs *c, struct btree *b)
213 return __btree_node_reclaim(c, b, false);
216 static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
218 return __btree_node_reclaim(c, b, true);
221 static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
222 struct shrink_control *sc)
224 struct bch_fs *c = container_of(shrink, struct bch_fs,
226 struct btree_cache *bc = &c->btree_cache;
228 unsigned long nr = sc->nr_to_scan;
229 unsigned long can_free;
230 unsigned long touched = 0;
231 unsigned long freed = 0;
234 if (btree_shrinker_disabled(c))
237 /* Return -1 if we can't do anything right now */
238 if (sc->gfp_mask & __GFP_IO)
239 mutex_lock(&bc->lock);
240 else if (!mutex_trylock(&bc->lock))
244 * It's _really_ critical that we don't free too many btree nodes - we
245 * have to always leave ourselves a reserve. The reserve is how we
246 * guarantee that allocating memory for a new btree node can always
247 * succeed, so that inserting keys into the btree can always succeed and
248 * IO can always make forward progress:
250 nr /= btree_pages(c);
251 can_free = btree_cache_can_free(bc);
252 nr = min_t(unsigned long, nr, can_free);
255 list_for_each_entry_safe(b, t, &bc->freeable, list) {
262 !btree_node_reclaim(c, b)) {
263 btree_node_data_free(c, b);
264 six_unlock_write(&b->lock);
265 six_unlock_intent(&b->lock);
270 list_for_each_entry_safe(b, t, &bc->live, list) {
275 if (&t->list != &bc->live)
276 list_move_tail(&bc->live, &t->list);
280 if (!btree_node_accessed(b) &&
281 !btree_node_reclaim(c, b)) {
282 /* can't call bch2_btree_node_hash_remove under lock */
284 if (&t->list != &bc->live)
285 list_move_tail(&bc->live, &t->list);
287 btree_node_data_free(c, b);
288 mutex_unlock(&bc->lock);
290 bch2_btree_node_hash_remove(bc, b);
291 six_unlock_write(&b->lock);
292 six_unlock_intent(&b->lock);
297 if (sc->gfp_mask & __GFP_IO)
298 mutex_lock(&bc->lock);
299 else if (!mutex_trylock(&bc->lock))
303 clear_btree_node_accessed(b);
306 mutex_unlock(&bc->lock);
308 return (unsigned long) freed * btree_pages(c);
311 static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
312 struct shrink_control *sc)
314 struct bch_fs *c = container_of(shrink, struct bch_fs,
316 struct btree_cache *bc = &c->btree_cache;
318 if (btree_shrinker_disabled(c))
321 return btree_cache_can_free(bc) * btree_pages(c);
324 void bch2_fs_btree_cache_exit(struct bch_fs *c)
326 struct btree_cache *bc = &c->btree_cache;
330 if (bc->shrink.list.next)
331 unregister_shrinker(&bc->shrink);
333 mutex_lock(&bc->lock);
335 #ifdef CONFIG_BCACHEFS_DEBUG
337 list_move(&c->verify_data->list, &bc->live);
339 kvpfree(c->verify_ondisk, btree_bytes(c));
342 for (i = 0; i < BTREE_ID_NR; i++)
343 if (c->btree_roots[i].b)
344 list_add(&c->btree_roots[i].b->list, &bc->live);
346 list_splice(&bc->freeable, &bc->live);
348 while (!list_empty(&bc->live)) {
349 b = list_first_entry(&bc->live, struct btree, list);
351 BUG_ON(btree_node_read_in_flight(b) ||
352 btree_node_write_in_flight(b));
354 if (btree_node_dirty(b))
355 bch2_btree_complete_write(c, b, btree_current_write(b));
356 clear_btree_node_dirty(b);
358 btree_node_data_free(c, b);
361 while (!list_empty(&bc->freed)) {
362 b = list_first_entry(&bc->freed, struct btree, list);
367 mutex_unlock(&bc->lock);
369 if (bc->table_init_done)
370 rhashtable_destroy(&bc->table);
373 int bch2_fs_btree_cache_init(struct bch_fs *c)
375 struct btree_cache *bc = &c->btree_cache;
379 pr_verbose_init(c->opts, "");
381 ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
385 bc->table_init_done = true;
387 bch2_recalc_btree_reserve(c);
389 for (i = 0; i < bc->reserve; i++)
390 if (!btree_node_mem_alloc(c, GFP_KERNEL)) {
395 list_splice_init(&bc->live, &bc->freeable);
397 #ifdef CONFIG_BCACHEFS_DEBUG
398 mutex_init(&c->verify_lock);
400 c->verify_ondisk = kvpmalloc(btree_bytes(c), GFP_KERNEL);
401 if (!c->verify_ondisk) {
406 c->verify_data = btree_node_mem_alloc(c, GFP_KERNEL);
407 if (!c->verify_data) {
412 list_del_init(&c->verify_data->list);
415 bc->shrink.count_objects = bch2_btree_cache_count;
416 bc->shrink.scan_objects = bch2_btree_cache_scan;
417 bc->shrink.seeks = 4;
418 bc->shrink.batch = btree_pages(c) * 2;
419 register_shrinker(&bc->shrink);
421 pr_verbose_init(c->opts, "ret %i", ret);
425 void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
427 mutex_init(&bc->lock);
428 INIT_LIST_HEAD(&bc->live);
429 INIT_LIST_HEAD(&bc->freeable);
430 INIT_LIST_HEAD(&bc->freed);
434 * We can only have one thread cannibalizing other cached btree nodes at a time,
435 * or we'll deadlock. We use an open coded mutex to ensure that, which a
436 * cannibalize_bucket() will take. This means every time we unlock the root of
437 * the btree, we need to release this lock if we have it held.
439 void bch2_btree_cache_cannibalize_unlock(struct bch_fs *c)
441 struct btree_cache *bc = &c->btree_cache;
443 if (bc->alloc_lock == current) {
444 trace_btree_node_cannibalize_unlock(c);
445 bc->alloc_lock = NULL;
446 closure_wake_up(&bc->alloc_wait);
450 int bch2_btree_cache_cannibalize_lock(struct bch_fs *c, struct closure *cl)
452 struct btree_cache *bc = &c->btree_cache;
453 struct task_struct *old;
455 old = cmpxchg(&bc->alloc_lock, NULL, current);
456 if (old == NULL || old == current)
460 trace_btree_node_cannibalize_lock_fail(c);
464 closure_wait(&bc->alloc_wait, cl);
466 /* Try again, after adding ourselves to waitlist */
467 old = cmpxchg(&bc->alloc_lock, NULL, current);
468 if (old == NULL || old == current) {
470 closure_wake_up(&bc->alloc_wait);
474 trace_btree_node_cannibalize_lock_fail(c);
478 trace_btree_node_cannibalize_lock(c);
482 static struct btree *btree_node_cannibalize(struct bch_fs *c)
484 struct btree_cache *bc = &c->btree_cache;
487 list_for_each_entry_reverse(b, &bc->live, list)
488 if (!btree_node_reclaim(c, b))
492 list_for_each_entry_reverse(b, &bc->live, list)
493 if (!btree_node_write_and_reclaim(c, b))
497 * Rare case: all nodes were intent-locked.
500 WARN_ONCE(1, "btree cache cannibalize failed\n");
505 struct btree *bch2_btree_node_mem_alloc(struct bch_fs *c)
507 struct btree_cache *bc = &c->btree_cache;
509 u64 start_time = local_clock();
511 mutex_lock(&bc->lock);
514 * btree_free() doesn't free memory; it sticks the node on the end of
515 * the list. Check if there's any freed nodes there:
517 list_for_each_entry(b, &bc->freeable, list)
518 if (!btree_node_reclaim(c, b))
522 * We never free struct btree itself, just the memory that holds the on
523 * disk node. Check the freed list before allocating a new one:
525 list_for_each_entry(b, &bc->freed, list)
526 if (!btree_node_reclaim(c, b)) {
527 btree_node_data_alloc(c, b, __GFP_NOWARN|GFP_NOIO);
531 six_unlock_write(&b->lock);
532 six_unlock_intent(&b->lock);
536 b = btree_node_mem_alloc(c, __GFP_NOWARN|GFP_NOIO);
540 BUG_ON(!six_trylock_intent(&b->lock));
541 BUG_ON(!six_trylock_write(&b->lock));
543 BUG_ON(btree_node_hashed(b));
544 BUG_ON(btree_node_write_in_flight(b));
546 list_del_init(&b->list);
547 mutex_unlock(&bc->lock);
554 b->whiteout_u64s = 0;
555 b->uncompacted_whiteout_u64s = 0;
556 bch2_btree_keys_init(b, &c->expensive_debug_checks);
558 bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
563 /* Try to cannibalize another cached btree node: */
564 if (bc->alloc_lock == current) {
565 b = btree_node_cannibalize(c);
566 list_del_init(&b->list);
567 mutex_unlock(&bc->lock);
569 bch2_btree_node_hash_remove(bc, b);
571 trace_btree_node_cannibalize(c);
575 mutex_unlock(&bc->lock);
576 return ERR_PTR(-ENOMEM);
579 /* Slowpath, don't want it inlined into btree_iter_traverse() */
580 static noinline struct btree *bch2_btree_node_fill(struct bch_fs *c,
581 struct btree_iter *iter,
582 const struct bkey_i *k,
584 enum six_lock_type lock_type,
587 struct btree_cache *bc = &c->btree_cache;
591 * Parent node must be locked, else we could read in a btree node that's
594 BUG_ON(!btree_node_locked(iter, level + 1));
595 BUG_ON(level >= BTREE_MAX_DEPTH);
597 b = bch2_btree_node_mem_alloc(c);
601 bkey_copy(&b->key, k);
602 if (bch2_btree_node_hash_insert(bc, b, level, iter->btree_id)) {
603 /* raced with another fill: */
605 /* mark as unhashed... */
606 PTR_HASH(&b->key) = 0;
608 mutex_lock(&bc->lock);
609 list_add(&b->list, &bc->freeable);
610 mutex_unlock(&bc->lock);
612 six_unlock_write(&b->lock);
613 six_unlock_intent(&b->lock);
618 * If the btree node wasn't cached, we can't drop our lock on
619 * the parent until after it's added to the cache - because
620 * otherwise we could race with a btree_split() freeing the node
621 * we're trying to lock.
623 * But the deadlock described below doesn't exist in this case,
624 * so it's safe to not drop the parent lock until here:
626 if (btree_node_read_locked(iter, level + 1))
627 btree_node_unlock(iter, level + 1);
629 bch2_btree_node_read(c, b, sync);
631 six_unlock_write(&b->lock);
634 six_unlock_intent(&b->lock);
638 if (lock_type == SIX_LOCK_read)
639 six_lock_downgrade(&b->lock);
645 * bch_btree_node_get - find a btree node in the cache and lock it, reading it
646 * in from disk if necessary.
648 * If IO is necessary and running under generic_make_request, returns -EAGAIN.
650 * The btree node will have either a read or a write lock held, depending on
651 * the @write parameter.
653 struct btree *bch2_btree_node_get(struct bch_fs *c, struct btree_iter *iter,
654 const struct bkey_i *k, unsigned level,
655 enum six_lock_type lock_type,
658 struct btree_cache *bc = &c->btree_cache;
663 * XXX: locking optimization
665 * we can make the locking looser here - caller can drop lock on parent
666 * node before locking child node (and potentially blocking): we just
667 * have to have bch2_btree_node_fill() call relock on the parent and
668 * return -EINTR if that fails
670 EBUG_ON(!btree_node_locked(iter, level + 1));
671 EBUG_ON(level >= BTREE_MAX_DEPTH);
674 b = btree_cache_find(bc, k);
679 * We must have the parent locked to call bch2_btree_node_fill(),
680 * else we could read in a btree node from disk that's been
683 b = bch2_btree_node_fill(c, iter, k, level, lock_type, true);
685 /* We raced and found the btree node in the cache */
693 * There's a potential deadlock with splits and insertions into
694 * interior nodes we have to avoid:
696 * The other thread might be holding an intent lock on the node
697 * we want, and they want to update its parent node so they're
698 * going to upgrade their intent lock on the parent node to a
701 * But if we're holding a read lock on the parent, and we're
702 * trying to get the intent lock they're holding, we deadlock.
704 * So to avoid this we drop the read locks on parent nodes when
705 * we're starting to take intent locks - and handle the race.
707 * The race is that they might be about to free the node we
708 * want, and dropping our read lock on the parent node lets them
709 * update the parent marking the node we want as freed, and then
712 * To guard against this, btree nodes are evicted from the cache
713 * when they're freed - and PTR_HASH() is zeroed out, which we
714 * check for after we lock the node.
716 * Then, bch2_btree_node_relock() on the parent will fail - because
717 * the parent was modified, when the pointer to the node we want
718 * was removed - and we'll bail out:
720 if (btree_node_read_locked(iter, level + 1))
721 btree_node_unlock(iter, level + 1);
723 if (!btree_node_lock(b, k->k.p, level, iter,
724 lock_type, may_drop_locks))
725 return ERR_PTR(-EINTR);
727 if (unlikely(PTR_HASH(&b->key) != PTR_HASH(k) ||
730 six_unlock_type(&b->lock, lock_type);
731 if (bch2_btree_node_relock(iter, level + 1))
735 return ERR_PTR(-EINTR);
739 wait_on_bit_io(&b->flags, BTREE_NODE_read_in_flight,
740 TASK_UNINTERRUPTIBLE);
742 prefetch(b->aux_data);
744 for_each_bset(b, t) {
745 void *p = (u64 *) b->aux_data + t->aux_data_offset;
747 prefetch(p + L1_CACHE_BYTES * 0);
748 prefetch(p + L1_CACHE_BYTES * 1);
749 prefetch(p + L1_CACHE_BYTES * 2);
752 /* avoid atomic set bit if it's not needed: */
753 if (btree_node_accessed(b))
754 set_btree_node_accessed(b);
756 if (unlikely(btree_node_read_error(b))) {
757 six_unlock_type(&b->lock, lock_type);
758 return ERR_PTR(-EIO);
761 EBUG_ON(b->btree_id != iter->btree_id ||
762 BTREE_NODE_LEVEL(b->data) != level ||
763 bkey_cmp(b->data->max_key, k->k.p));
768 struct btree *bch2_btree_node_get_sibling(struct bch_fs *c,
769 struct btree_iter *iter,
772 enum btree_node_sibling sib)
774 struct btree *parent;
775 struct btree_node_iter node_iter;
776 struct bkey_packed *k;
778 struct btree *ret = NULL;
779 unsigned level = b->level;
781 parent = btree_iter_node(iter, level + 1);
785 if (!bch2_btree_node_relock(iter, level + 1))
788 node_iter = iter->l[parent->level].iter;
790 k = bch2_btree_node_iter_peek_all(&node_iter, parent);
791 BUG_ON(bkey_cmp_left_packed(parent, k, &b->key.k.p));
793 k = sib == btree_prev_sib
794 ? bch2_btree_node_iter_prev(&node_iter, parent)
795 : (bch2_btree_node_iter_advance(&node_iter, parent),
796 bch2_btree_node_iter_peek(&node_iter, parent));
800 bch2_bkey_unpack(parent, &tmp.k, k);
802 ret = bch2_btree_node_get(c, iter, &tmp.k, level,
803 SIX_LOCK_intent, may_drop_locks);
805 if (PTR_ERR_OR_ZERO(ret) == -EINTR && may_drop_locks) {
806 struct btree_iter *linked;
808 if (!bch2_btree_node_relock(iter, level + 1))
812 * We might have got -EINTR because trylock failed, and we're
813 * holding other locks that would cause us to deadlock:
815 trans_for_each_iter(iter->trans, linked)
816 if (btree_iter_cmp(iter, linked) < 0)
817 __bch2_btree_iter_unlock(linked);
819 if (sib == btree_prev_sib)
820 btree_node_unlock(iter, level);
822 ret = bch2_btree_node_get(c, iter, &tmp.k, level,
823 SIX_LOCK_intent, may_drop_locks);
826 * before btree_iter_relock() calls btree_iter_verify_locks():
828 if (btree_lock_want(iter, level + 1) == BTREE_NODE_UNLOCKED)
829 btree_node_unlock(iter, level + 1);
831 if (!bch2_btree_node_relock(iter, level)) {
832 btree_iter_set_dirty(iter, BTREE_ITER_NEED_RELOCK);
835 six_unlock_intent(&ret->lock);
836 ret = ERR_PTR(-EINTR);
840 bch2_btree_trans_relock(iter->trans);
843 if (btree_lock_want(iter, level + 1) == BTREE_NODE_UNLOCKED)
844 btree_node_unlock(iter, level + 1);
846 bch2_btree_trans_verify_locks(iter->trans);
848 BUG_ON((!may_drop_locks || !IS_ERR(ret)) &&
849 (iter->uptodate >= BTREE_ITER_NEED_RELOCK ||
850 !btree_node_locked(iter, level)));
852 if (!IS_ERR_OR_NULL(ret)) {
853 struct btree *n1 = ret, *n2 = b;
855 if (sib != btree_prev_sib)
858 BUG_ON(bkey_cmp(btree_type_successor(n1->btree_id,
866 bch2_btree_iter_upgrade(iter, level + 2, true);
867 ret = ERR_PTR(-EINTR);
871 void bch2_btree_node_prefetch(struct bch_fs *c, struct btree_iter *iter,
872 const struct bkey_i *k, unsigned level)
874 struct btree_cache *bc = &c->btree_cache;
877 BUG_ON(!btree_node_locked(iter, level + 1));
878 BUG_ON(level >= BTREE_MAX_DEPTH);
881 b = btree_cache_find(bc, k);
887 bch2_btree_node_fill(c, iter, k, level, SIX_LOCK_read, false);
890 void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
893 const struct bkey_format *f = &b->format;
894 struct bset_stats stats;
896 memset(&stats, 0, sizeof(stats));
898 bch2_btree_keys_stats(b, &stats);
901 "l %u %llu:%llu - %llu:%llu:\n"
904 b->data->min_key.inode,
905 b->data->min_key.offset,
906 b->data->max_key.inode,
907 b->data->max_key.offset);
908 bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
910 " format: u64s %u fields %u %u %u %u %u\n"
911 " unpack fn len: %u\n"
912 " bytes used %zu/%zu (%zu%% full)\n"
913 " sib u64s: %u, %u (merge threshold %zu)\n"
914 " nr packed keys %u\n"
915 " nr unpacked keys %u\n"
917 " failed unpacked %zu\n"
919 " failed overflow %zu\n",
921 f->bits_per_field[0],
922 f->bits_per_field[1],
923 f->bits_per_field[2],
924 f->bits_per_field[3],
925 f->bits_per_field[4],
927 b->nr.live_u64s * sizeof(u64),
928 btree_bytes(c) - sizeof(struct btree_node),
929 b->nr.live_u64s * 100 / btree_max_u64s(c),
932 BTREE_FOREGROUND_MERGE_THRESHOLD(c),
936 stats.failed_unpacked,
938 stats.failed_overflow);