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Merge tag 'loongarch-kvm-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhu...
[thirdparty/kernel/stable.git] / fs / bcachefs / btree_key_cache.c
1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "bcachefs.h"
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"
9 #include "errcode.h"
10 #include "error.h"
11 #include "journal.h"
12 #include "journal_reclaim.h"
13 #include "trace.h"
14
15 #include <linux/sched/mm.h>
16
17 static inline bool btree_uses_pcpu_readers(enum btree_id id)
18 {
19 return id == BTREE_ID_subvolumes;
20 }
21
22 static struct kmem_cache *bch2_key_cache;
23
24 static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
25 const void *obj)
26 {
27 const struct bkey_cached *ck = obj;
28 const struct bkey_cached_key *key = arg->key;
29
30 return ck->key.btree_id != key->btree_id ||
31 !bpos_eq(ck->key.pos, key->pos);
32 }
33
34 static const struct rhashtable_params bch2_btree_key_cache_params = {
35 .head_offset = offsetof(struct bkey_cached, hash),
36 .key_offset = offsetof(struct bkey_cached, key),
37 .key_len = sizeof(struct bkey_cached_key),
38 .obj_cmpfn = bch2_btree_key_cache_cmp_fn,
39 };
40
41 __flatten
42 inline struct bkey_cached *
43 bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
44 {
45 struct bkey_cached_key key = {
46 .btree_id = btree_id,
47 .pos = pos,
48 };
49
50 return rhashtable_lookup_fast(&c->btree_key_cache.table, &key,
51 bch2_btree_key_cache_params);
52 }
53
54 static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
55 {
56 if (!six_trylock_intent(&ck->c.lock))
57 return false;
58
59 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
60 six_unlock_intent(&ck->c.lock);
61 return false;
62 }
63
64 if (!six_trylock_write(&ck->c.lock)) {
65 six_unlock_intent(&ck->c.lock);
66 return false;
67 }
68
69 return true;
70 }
71
72 static void bkey_cached_evict(struct btree_key_cache *c,
73 struct bkey_cached *ck)
74 {
75 BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
76 bch2_btree_key_cache_params));
77 memset(&ck->key, ~0, sizeof(ck->key));
78
79 atomic_long_dec(&c->nr_keys);
80 }
81
82 static void bkey_cached_free(struct btree_key_cache *bc,
83 struct bkey_cached *ck)
84 {
85 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
86
87 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
88
89 ck->btree_trans_barrier_seq =
90 start_poll_synchronize_srcu(&c->btree_trans_barrier);
91
92 if (ck->c.lock.readers) {
93 list_move_tail(&ck->list, &bc->freed_pcpu);
94 bc->nr_freed_pcpu++;
95 } else {
96 list_move_tail(&ck->list, &bc->freed_nonpcpu);
97 bc->nr_freed_nonpcpu++;
98 }
99 atomic_long_inc(&bc->nr_freed);
100
101 kfree(ck->k);
102 ck->k = NULL;
103 ck->u64s = 0;
104
105 six_unlock_write(&ck->c.lock);
106 six_unlock_intent(&ck->c.lock);
107 }
108
109 #ifdef __KERNEL__
110 static void __bkey_cached_move_to_freelist_ordered(struct btree_key_cache *bc,
111 struct bkey_cached *ck)
112 {
113 struct bkey_cached *pos;
114
115 bc->nr_freed_nonpcpu++;
116
117 list_for_each_entry_reverse(pos, &bc->freed_nonpcpu, list) {
118 if (ULONG_CMP_GE(ck->btree_trans_barrier_seq,
119 pos->btree_trans_barrier_seq)) {
120 list_move(&ck->list, &pos->list);
121 return;
122 }
123 }
124
125 list_move(&ck->list, &bc->freed_nonpcpu);
126 }
127 #endif
128
129 static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
130 struct bkey_cached *ck)
131 {
132 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
133
134 if (!ck->c.lock.readers) {
135 #ifdef __KERNEL__
136 struct btree_key_cache_freelist *f;
137 bool freed = false;
138
139 preempt_disable();
140 f = this_cpu_ptr(bc->pcpu_freed);
141
142 if (f->nr < ARRAY_SIZE(f->objs)) {
143 f->objs[f->nr++] = ck;
144 freed = true;
145 }
146 preempt_enable();
147
148 if (!freed) {
149 mutex_lock(&bc->lock);
150 preempt_disable();
151 f = this_cpu_ptr(bc->pcpu_freed);
152
153 while (f->nr > ARRAY_SIZE(f->objs) / 2) {
154 struct bkey_cached *ck2 = f->objs[--f->nr];
155
156 __bkey_cached_move_to_freelist_ordered(bc, ck2);
157 }
158 preempt_enable();
159
160 __bkey_cached_move_to_freelist_ordered(bc, ck);
161 mutex_unlock(&bc->lock);
162 }
163 #else
164 mutex_lock(&bc->lock);
165 list_move_tail(&ck->list, &bc->freed_nonpcpu);
166 bc->nr_freed_nonpcpu++;
167 mutex_unlock(&bc->lock);
168 #endif
169 } else {
170 mutex_lock(&bc->lock);
171 list_move_tail(&ck->list, &bc->freed_pcpu);
172 mutex_unlock(&bc->lock);
173 }
174 }
175
176 static void bkey_cached_free_fast(struct btree_key_cache *bc,
177 struct bkey_cached *ck)
178 {
179 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
180
181 ck->btree_trans_barrier_seq =
182 start_poll_synchronize_srcu(&c->btree_trans_barrier);
183
184 list_del_init(&ck->list);
185 atomic_long_inc(&bc->nr_freed);
186
187 kfree(ck->k);
188 ck->k = NULL;
189 ck->u64s = 0;
190
191 bkey_cached_move_to_freelist(bc, ck);
192
193 six_unlock_write(&ck->c.lock);
194 six_unlock_intent(&ck->c.lock);
195 }
196
197 static struct bkey_cached *
198 bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
199 bool *was_new)
200 {
201 struct bch_fs *c = trans->c;
202 struct btree_key_cache *bc = &c->btree_key_cache;
203 struct bkey_cached *ck = NULL;
204 bool pcpu_readers = btree_uses_pcpu_readers(path->btree_id);
205 int ret;
206
207 if (!pcpu_readers) {
208 #ifdef __KERNEL__
209 struct btree_key_cache_freelist *f;
210
211 preempt_disable();
212 f = this_cpu_ptr(bc->pcpu_freed);
213 if (f->nr)
214 ck = f->objs[--f->nr];
215 preempt_enable();
216
217 if (!ck) {
218 mutex_lock(&bc->lock);
219 preempt_disable();
220 f = this_cpu_ptr(bc->pcpu_freed);
221
222 while (!list_empty(&bc->freed_nonpcpu) &&
223 f->nr < ARRAY_SIZE(f->objs) / 2) {
224 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
225 list_del_init(&ck->list);
226 bc->nr_freed_nonpcpu--;
227 f->objs[f->nr++] = ck;
228 }
229
230 ck = f->nr ? f->objs[--f->nr] : NULL;
231 preempt_enable();
232 mutex_unlock(&bc->lock);
233 }
234 #else
235 mutex_lock(&bc->lock);
236 if (!list_empty(&bc->freed_nonpcpu)) {
237 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
238 list_del_init(&ck->list);
239 bc->nr_freed_nonpcpu--;
240 }
241 mutex_unlock(&bc->lock);
242 #endif
243 } else {
244 mutex_lock(&bc->lock);
245 if (!list_empty(&bc->freed_pcpu)) {
246 ck = list_last_entry(&bc->freed_pcpu, struct bkey_cached, list);
247 list_del_init(&ck->list);
248 }
249 mutex_unlock(&bc->lock);
250 }
251
252 if (ck) {
253 ret = btree_node_lock_nopath(trans, &ck->c, SIX_LOCK_intent, _THIS_IP_);
254 if (unlikely(ret)) {
255 bkey_cached_move_to_freelist(bc, ck);
256 return ERR_PTR(ret);
257 }
258
259 path->l[0].b = (void *) ck;
260 path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
261 mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
262
263 ret = bch2_btree_node_lock_write(trans, path, &ck->c);
264 if (unlikely(ret)) {
265 btree_node_unlock(trans, path, 0);
266 bkey_cached_move_to_freelist(bc, ck);
267 return ERR_PTR(ret);
268 }
269
270 return ck;
271 }
272
273 ck = allocate_dropping_locks(trans, ret,
274 kmem_cache_zalloc(bch2_key_cache, _gfp));
275 if (ret) {
276 kmem_cache_free(bch2_key_cache, ck);
277 return ERR_PTR(ret);
278 }
279
280 if (!ck)
281 return NULL;
282
283 INIT_LIST_HEAD(&ck->list);
284 bch2_btree_lock_init(&ck->c, pcpu_readers ? SIX_LOCK_INIT_PCPU : 0);
285
286 ck->c.cached = true;
287 BUG_ON(!six_trylock_intent(&ck->c.lock));
288 BUG_ON(!six_trylock_write(&ck->c.lock));
289 *was_new = true;
290 return ck;
291 }
292
293 static struct bkey_cached *
294 bkey_cached_reuse(struct btree_key_cache *c)
295 {
296 struct bucket_table *tbl;
297 struct rhash_head *pos;
298 struct bkey_cached *ck;
299 unsigned i;
300
301 mutex_lock(&c->lock);
302 rcu_read_lock();
303 tbl = rht_dereference_rcu(c->table.tbl, &c->table);
304 for (i = 0; i < tbl->size; i++)
305 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
306 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
307 bkey_cached_lock_for_evict(ck)) {
308 bkey_cached_evict(c, ck);
309 goto out;
310 }
311 }
312 ck = NULL;
313 out:
314 rcu_read_unlock();
315 mutex_unlock(&c->lock);
316 return ck;
317 }
318
319 static struct bkey_cached *
320 btree_key_cache_create(struct btree_trans *trans, struct btree_path *path)
321 {
322 struct bch_fs *c = trans->c;
323 struct btree_key_cache *bc = &c->btree_key_cache;
324 struct bkey_cached *ck;
325 bool was_new = false;
326
327 ck = bkey_cached_alloc(trans, path, &was_new);
328 if (IS_ERR(ck))
329 return ck;
330
331 if (unlikely(!ck)) {
332 ck = bkey_cached_reuse(bc);
333 if (unlikely(!ck)) {
334 bch_err(c, "error allocating memory for key cache item, btree %s",
335 bch2_btree_id_str(path->btree_id));
336 return ERR_PTR(-BCH_ERR_ENOMEM_btree_key_cache_create);
337 }
338
339 mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
340 }
341
342 ck->c.level = 0;
343 ck->c.btree_id = path->btree_id;
344 ck->key.btree_id = path->btree_id;
345 ck->key.pos = path->pos;
346 ck->valid = false;
347 ck->flags = 1U << BKEY_CACHED_ACCESSED;
348
349 if (unlikely(rhashtable_lookup_insert_fast(&bc->table,
350 &ck->hash,
351 bch2_btree_key_cache_params))) {
352 /* We raced with another fill: */
353
354 if (likely(was_new)) {
355 six_unlock_write(&ck->c.lock);
356 six_unlock_intent(&ck->c.lock);
357 kfree(ck);
358 } else {
359 bkey_cached_free_fast(bc, ck);
360 }
361
362 mark_btree_node_locked(trans, path, 0, BTREE_NODE_UNLOCKED);
363 return NULL;
364 }
365
366 atomic_long_inc(&bc->nr_keys);
367
368 six_unlock_write(&ck->c.lock);
369
370 return ck;
371 }
372
373 static int btree_key_cache_fill(struct btree_trans *trans,
374 struct btree_path *ck_path,
375 struct bkey_cached *ck)
376 {
377 struct btree_iter iter;
378 struct bkey_s_c k;
379 unsigned new_u64s = 0;
380 struct bkey_i *new_k = NULL;
381 int ret;
382
383 k = bch2_bkey_get_iter(trans, &iter, ck->key.btree_id, ck->key.pos,
384 BTREE_ITER_KEY_CACHE_FILL|
385 BTREE_ITER_CACHED_NOFILL);
386 ret = bkey_err(k);
387 if (ret)
388 goto err;
389
390 if (!bch2_btree_node_relock(trans, ck_path, 0)) {
391 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
392 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
393 goto err;
394 }
395
396 /*
397 * bch2_varint_decode can read past the end of the buffer by at
398 * most 7 bytes (it won't be used):
399 */
400 new_u64s = k.k->u64s + 1;
401
402 /*
403 * Allocate some extra space so that the transaction commit path is less
404 * likely to have to reallocate, since that requires a transaction
405 * restart:
406 */
407 new_u64s = min(256U, (new_u64s * 3) / 2);
408
409 if (new_u64s > ck->u64s) {
410 new_u64s = roundup_pow_of_two(new_u64s);
411 new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOWAIT|__GFP_NOWARN);
412 if (!new_k) {
413 bch2_trans_unlock(trans);
414
415 new_k = kmalloc(new_u64s * sizeof(u64), GFP_KERNEL);
416 if (!new_k) {
417 bch_err(trans->c, "error allocating memory for key cache key, btree %s u64s %u",
418 bch2_btree_id_str(ck->key.btree_id), new_u64s);
419 ret = -BCH_ERR_ENOMEM_btree_key_cache_fill;
420 goto err;
421 }
422
423 if (!bch2_btree_node_relock(trans, ck_path, 0)) {
424 kfree(new_k);
425 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
426 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_fill);
427 goto err;
428 }
429
430 ret = bch2_trans_relock(trans);
431 if (ret) {
432 kfree(new_k);
433 goto err;
434 }
435 }
436 }
437
438 ret = bch2_btree_node_lock_write(trans, ck_path, &ck_path->l[0].b->c);
439 if (ret) {
440 kfree(new_k);
441 goto err;
442 }
443
444 if (new_k) {
445 kfree(ck->k);
446 ck->u64s = new_u64s;
447 ck->k = new_k;
448 }
449
450 bkey_reassemble(ck->k, k);
451 ck->valid = true;
452 bch2_btree_node_unlock_write(trans, ck_path, ck_path->l[0].b);
453
454 /* We're not likely to need this iterator again: */
455 set_btree_iter_dontneed(&iter);
456 err:
457 bch2_trans_iter_exit(trans, &iter);
458 return ret;
459 }
460
461 static noinline int
462 bch2_btree_path_traverse_cached_slowpath(struct btree_trans *trans, struct btree_path *path,
463 unsigned flags)
464 {
465 struct bch_fs *c = trans->c;
466 struct bkey_cached *ck;
467 int ret = 0;
468
469 BUG_ON(path->level);
470
471 path->l[1].b = NULL;
472
473 if (bch2_btree_node_relock_notrace(trans, path, 0)) {
474 ck = (void *) path->l[0].b;
475 goto fill;
476 }
477 retry:
478 ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
479 if (!ck) {
480 ck = btree_key_cache_create(trans, path);
481 ret = PTR_ERR_OR_ZERO(ck);
482 if (ret)
483 goto err;
484 if (!ck)
485 goto retry;
486
487 mark_btree_node_locked(trans, path, 0, BTREE_NODE_INTENT_LOCKED);
488 path->locks_want = 1;
489 } else {
490 enum six_lock_type lock_want = __btree_lock_want(path, 0);
491
492 ret = btree_node_lock(trans, path, (void *) ck, 0,
493 lock_want, _THIS_IP_);
494 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
495 goto err;
496
497 BUG_ON(ret);
498
499 if (ck->key.btree_id != path->btree_id ||
500 !bpos_eq(ck->key.pos, path->pos)) {
501 six_unlock_type(&ck->c.lock, lock_want);
502 goto retry;
503 }
504
505 mark_btree_node_locked(trans, path, 0,
506 (enum btree_node_locked_type) lock_want);
507 }
508
509 path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
510 path->l[0].b = (void *) ck;
511 fill:
512 path->uptodate = BTREE_ITER_UPTODATE;
513
514 if (!ck->valid && !(flags & BTREE_ITER_CACHED_NOFILL)) {
515 /*
516 * Using the underscore version because we haven't set
517 * path->uptodate yet:
518 */
519 if (!path->locks_want &&
520 !__bch2_btree_path_upgrade(trans, path, 1, NULL)) {
521 trace_and_count(trans->c, trans_restart_key_cache_upgrade, trans, _THIS_IP_);
522 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_key_cache_upgrade);
523 goto err;
524 }
525
526 ret = btree_key_cache_fill(trans, path, ck);
527 if (ret)
528 goto err;
529
530 ret = bch2_btree_path_relock(trans, path, _THIS_IP_);
531 if (ret)
532 goto err;
533
534 path->uptodate = BTREE_ITER_UPTODATE;
535 }
536
537 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
538 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
539
540 BUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
541 BUG_ON(path->uptodate);
542
543 return ret;
544 err:
545 path->uptodate = BTREE_ITER_NEED_TRAVERSE;
546 if (!bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
547 btree_node_unlock(trans, path, 0);
548 path->l[0].b = ERR_PTR(ret);
549 }
550 return ret;
551 }
552
553 int bch2_btree_path_traverse_cached(struct btree_trans *trans, struct btree_path *path,
554 unsigned flags)
555 {
556 struct bch_fs *c = trans->c;
557 struct bkey_cached *ck;
558 int ret = 0;
559
560 EBUG_ON(path->level);
561
562 path->l[1].b = NULL;
563
564 if (bch2_btree_node_relock_notrace(trans, path, 0)) {
565 ck = (void *) path->l[0].b;
566 goto fill;
567 }
568 retry:
569 ck = bch2_btree_key_cache_find(c, path->btree_id, path->pos);
570 if (!ck) {
571 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
572 } else {
573 enum six_lock_type lock_want = __btree_lock_want(path, 0);
574
575 ret = btree_node_lock(trans, path, (void *) ck, 0,
576 lock_want, _THIS_IP_);
577 EBUG_ON(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart));
578
579 if (ret)
580 return ret;
581
582 if (ck->key.btree_id != path->btree_id ||
583 !bpos_eq(ck->key.pos, path->pos)) {
584 six_unlock_type(&ck->c.lock, lock_want);
585 goto retry;
586 }
587
588 mark_btree_node_locked(trans, path, 0,
589 (enum btree_node_locked_type) lock_want);
590 }
591
592 path->l[0].lock_seq = six_lock_seq(&ck->c.lock);
593 path->l[0].b = (void *) ck;
594 fill:
595 if (!ck->valid)
596 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
597
598 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
599 set_bit(BKEY_CACHED_ACCESSED, &ck->flags);
600
601 path->uptodate = BTREE_ITER_UPTODATE;
602 EBUG_ON(!ck->valid);
603 EBUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
604
605 return ret;
606 }
607
608 static int btree_key_cache_flush_pos(struct btree_trans *trans,
609 struct bkey_cached_key key,
610 u64 journal_seq,
611 unsigned commit_flags,
612 bool evict)
613 {
614 struct bch_fs *c = trans->c;
615 struct journal *j = &c->journal;
616 struct btree_iter c_iter, b_iter;
617 struct bkey_cached *ck = NULL;
618 int ret;
619
620 bch2_trans_iter_init(trans, &b_iter, key.btree_id, key.pos,
621 BTREE_ITER_SLOTS|
622 BTREE_ITER_INTENT|
623 BTREE_ITER_ALL_SNAPSHOTS);
624 bch2_trans_iter_init(trans, &c_iter, key.btree_id, key.pos,
625 BTREE_ITER_CACHED|
626 BTREE_ITER_INTENT);
627 b_iter.flags &= ~BTREE_ITER_WITH_KEY_CACHE;
628
629 ret = bch2_btree_iter_traverse(&c_iter);
630 if (ret)
631 goto out;
632
633 ck = (void *) c_iter.path->l[0].b;
634 if (!ck)
635 goto out;
636
637 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
638 if (evict)
639 goto evict;
640 goto out;
641 }
642
643 BUG_ON(!ck->valid);
644
645 if (journal_seq && ck->journal.seq != journal_seq)
646 goto out;
647
648 /*
649 * Since journal reclaim depends on us making progress here, and the
650 * allocator/copygc depend on journal reclaim making progress, we need
651 * to be using alloc reserves:
652 */
653 ret = bch2_btree_iter_traverse(&b_iter) ?:
654 bch2_trans_update(trans, &b_iter, ck->k,
655 BTREE_UPDATE_KEY_CACHE_RECLAIM|
656 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
657 BTREE_TRIGGER_NORUN) ?:
658 bch2_trans_commit(trans, NULL, NULL,
659 BTREE_INSERT_NOCHECK_RW|
660 BTREE_INSERT_NOFAIL|
661 (ck->journal.seq == journal_last_seq(j)
662 ? BCH_WATERMARK_reclaim
663 : 0)|
664 commit_flags);
665
666 bch2_fs_fatal_err_on(ret &&
667 !bch2_err_matches(ret, BCH_ERR_transaction_restart) &&
668 !bch2_err_matches(ret, BCH_ERR_journal_reclaim_would_deadlock) &&
669 !bch2_journal_error(j), c,
670 "error flushing key cache: %s", bch2_err_str(ret));
671 if (ret)
672 goto out;
673
674 bch2_journal_pin_drop(j, &ck->journal);
675
676 BUG_ON(!btree_node_locked(c_iter.path, 0));
677
678 if (!evict) {
679 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
680 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
681 atomic_long_dec(&c->btree_key_cache.nr_dirty);
682 }
683 } else {
684 struct btree_path *path2;
685 evict:
686 trans_for_each_path(trans, path2)
687 if (path2 != c_iter.path)
688 __bch2_btree_path_unlock(trans, path2);
689
690 bch2_btree_node_lock_write_nofail(trans, c_iter.path, &ck->c);
691
692 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
693 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
694 atomic_long_dec(&c->btree_key_cache.nr_dirty);
695 }
696
697 mark_btree_node_locked_noreset(c_iter.path, 0, BTREE_NODE_UNLOCKED);
698 bkey_cached_evict(&c->btree_key_cache, ck);
699 bkey_cached_free_fast(&c->btree_key_cache, ck);
700 }
701 out:
702 bch2_trans_iter_exit(trans, &b_iter);
703 bch2_trans_iter_exit(trans, &c_iter);
704 return ret;
705 }
706
707 int bch2_btree_key_cache_journal_flush(struct journal *j,
708 struct journal_entry_pin *pin, u64 seq)
709 {
710 struct bch_fs *c = container_of(j, struct bch_fs, journal);
711 struct bkey_cached *ck =
712 container_of(pin, struct bkey_cached, journal);
713 struct bkey_cached_key key;
714 struct btree_trans *trans = bch2_trans_get(c);
715 int srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
716 int ret = 0;
717
718 btree_node_lock_nopath_nofail(trans, &ck->c, SIX_LOCK_read);
719 key = ck->key;
720
721 if (ck->journal.seq != seq ||
722 !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
723 six_unlock_read(&ck->c.lock);
724 goto unlock;
725 }
726
727 if (ck->seq != seq) {
728 bch2_journal_pin_update(&c->journal, ck->seq, &ck->journal,
729 bch2_btree_key_cache_journal_flush);
730 six_unlock_read(&ck->c.lock);
731 goto unlock;
732 }
733 six_unlock_read(&ck->c.lock);
734
735 ret = commit_do(trans, NULL, NULL, 0,
736 btree_key_cache_flush_pos(trans, key, seq,
737 BTREE_INSERT_JOURNAL_RECLAIM, false));
738 unlock:
739 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
740
741 bch2_trans_put(trans);
742 return ret;
743 }
744
745 /*
746 * Flush and evict a key from the key cache:
747 */
748 int bch2_btree_key_cache_flush(struct btree_trans *trans,
749 enum btree_id id, struct bpos pos)
750 {
751 struct bch_fs *c = trans->c;
752 struct bkey_cached_key key = { id, pos };
753
754 /* Fastpath - assume it won't be found: */
755 if (!bch2_btree_key_cache_find(c, id, pos))
756 return 0;
757
758 return btree_key_cache_flush_pos(trans, key, 0, 0, true);
759 }
760
761 bool bch2_btree_insert_key_cached(struct btree_trans *trans,
762 unsigned flags,
763 struct btree_insert_entry *insert_entry)
764 {
765 struct bch_fs *c = trans->c;
766 struct bkey_cached *ck = (void *) insert_entry->path->l[0].b;
767 struct bkey_i *insert = insert_entry->k;
768 bool kick_reclaim = false;
769
770 BUG_ON(insert->k.u64s > ck->u64s);
771
772 bkey_copy(ck->k, insert);
773 ck->valid = true;
774
775 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
776 EBUG_ON(test_bit(BCH_FS_CLEAN_SHUTDOWN, &c->flags));
777 set_bit(BKEY_CACHED_DIRTY, &ck->flags);
778 atomic_long_inc(&c->btree_key_cache.nr_dirty);
779
780 if (bch2_nr_btree_keys_need_flush(c))
781 kick_reclaim = true;
782 }
783
784 /*
785 * To minimize lock contention, we only add the journal pin here and
786 * defer pin updates to the flush callback via ->seq. Be careful not to
787 * update ->seq on nojournal commits because we don't want to update the
788 * pin to a seq that doesn't include journal updates on disk. Otherwise
789 * we risk losing the update after a crash.
790 *
791 * The only exception is if the pin is not active in the first place. We
792 * have to add the pin because journal reclaim drives key cache
793 * flushing. The flush callback will not proceed unless ->seq matches
794 * the latest pin, so make sure it starts with a consistent value.
795 */
796 if (!(insert_entry->flags & BTREE_UPDATE_NOJOURNAL) ||
797 !journal_pin_active(&ck->journal)) {
798 ck->seq = trans->journal_res.seq;
799 }
800 bch2_journal_pin_add(&c->journal, trans->journal_res.seq,
801 &ck->journal, bch2_btree_key_cache_journal_flush);
802
803 if (kick_reclaim)
804 journal_reclaim_kick(&c->journal);
805 return true;
806 }
807
808 void bch2_btree_key_cache_drop(struct btree_trans *trans,
809 struct btree_path *path)
810 {
811 struct bch_fs *c = trans->c;
812 struct bkey_cached *ck = (void *) path->l[0].b;
813
814 BUG_ON(!ck->valid);
815
816 /*
817 * We just did an update to the btree, bypassing the key cache: the key
818 * cache key is now stale and must be dropped, even if dirty:
819 */
820 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
821 clear_bit(BKEY_CACHED_DIRTY, &ck->flags);
822 atomic_long_dec(&c->btree_key_cache.nr_dirty);
823 bch2_journal_pin_drop(&c->journal, &ck->journal);
824 }
825
826 ck->valid = false;
827 }
828
829 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
830 struct shrink_control *sc)
831 {
832 struct bch_fs *c = shrink->private_data;
833 struct btree_key_cache *bc = &c->btree_key_cache;
834 struct bucket_table *tbl;
835 struct bkey_cached *ck, *t;
836 size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
837 unsigned start, flags;
838 int srcu_idx;
839
840 mutex_lock(&bc->lock);
841 srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
842 flags = memalloc_nofs_save();
843
844 /*
845 * Newest freed entries are at the end of the list - once we hit one
846 * that's too new to be freed, we can bail out:
847 */
848 scanned += bc->nr_freed_nonpcpu;
849
850 list_for_each_entry_safe(ck, t, &bc->freed_nonpcpu, list) {
851 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
852 ck->btree_trans_barrier_seq))
853 break;
854
855 list_del(&ck->list);
856 six_lock_exit(&ck->c.lock);
857 kmem_cache_free(bch2_key_cache, ck);
858 atomic_long_dec(&bc->nr_freed);
859 freed++;
860 bc->nr_freed_nonpcpu--;
861 }
862
863 if (scanned >= nr)
864 goto out;
865
866 scanned += bc->nr_freed_pcpu;
867
868 list_for_each_entry_safe(ck, t, &bc->freed_pcpu, list) {
869 if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
870 ck->btree_trans_barrier_seq))
871 break;
872
873 list_del(&ck->list);
874 six_lock_exit(&ck->c.lock);
875 kmem_cache_free(bch2_key_cache, ck);
876 atomic_long_dec(&bc->nr_freed);
877 freed++;
878 bc->nr_freed_pcpu--;
879 }
880
881 if (scanned >= nr)
882 goto out;
883
884 rcu_read_lock();
885 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
886 if (bc->shrink_iter >= tbl->size)
887 bc->shrink_iter = 0;
888 start = bc->shrink_iter;
889
890 do {
891 struct rhash_head *pos, *next;
892
893 pos = rht_ptr_rcu(rht_bucket(tbl, bc->shrink_iter));
894
895 while (!rht_is_a_nulls(pos)) {
896 next = rht_dereference_bucket_rcu(pos->next, tbl, bc->shrink_iter);
897 ck = container_of(pos, struct bkey_cached, hash);
898
899 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags))
900 goto next;
901
902 if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
903 clear_bit(BKEY_CACHED_ACCESSED, &ck->flags);
904 else if (bkey_cached_lock_for_evict(ck)) {
905 bkey_cached_evict(bc, ck);
906 bkey_cached_free(bc, ck);
907 }
908
909 scanned++;
910 if (scanned >= nr)
911 break;
912 next:
913 pos = next;
914 }
915
916 bc->shrink_iter++;
917 if (bc->shrink_iter >= tbl->size)
918 bc->shrink_iter = 0;
919 } while (scanned < nr && bc->shrink_iter != start);
920
921 rcu_read_unlock();
922 out:
923 memalloc_nofs_restore(flags);
924 srcu_read_unlock(&c->btree_trans_barrier, srcu_idx);
925 mutex_unlock(&bc->lock);
926
927 return freed;
928 }
929
930 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
931 struct shrink_control *sc)
932 {
933 struct bch_fs *c = shrink->private_data;
934 struct btree_key_cache *bc = &c->btree_key_cache;
935 long nr = atomic_long_read(&bc->nr_keys) -
936 atomic_long_read(&bc->nr_dirty);
937
938 return max(0L, nr);
939 }
940
941 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
942 {
943 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
944 struct bucket_table *tbl;
945 struct bkey_cached *ck, *n;
946 struct rhash_head *pos;
947 LIST_HEAD(items);
948 unsigned i;
949 #ifdef __KERNEL__
950 int cpu;
951 #endif
952
953 shrinker_free(bc->shrink);
954
955 mutex_lock(&bc->lock);
956
957 /*
958 * The loop is needed to guard against racing with rehash:
959 */
960 while (atomic_long_read(&bc->nr_keys)) {
961 rcu_read_lock();
962 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
963 if (tbl)
964 for (i = 0; i < tbl->size; i++)
965 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
966 bkey_cached_evict(bc, ck);
967 list_add(&ck->list, &items);
968 }
969 rcu_read_unlock();
970 }
971
972 #ifdef __KERNEL__
973 for_each_possible_cpu(cpu) {
974 struct btree_key_cache_freelist *f =
975 per_cpu_ptr(bc->pcpu_freed, cpu);
976
977 for (i = 0; i < f->nr; i++) {
978 ck = f->objs[i];
979 list_add(&ck->list, &items);
980 }
981 }
982 #endif
983
984 BUG_ON(list_count_nodes(&bc->freed_pcpu) != bc->nr_freed_pcpu);
985 BUG_ON(list_count_nodes(&bc->freed_nonpcpu) != bc->nr_freed_nonpcpu);
986
987 list_splice(&bc->freed_pcpu, &items);
988 list_splice(&bc->freed_nonpcpu, &items);
989
990 mutex_unlock(&bc->lock);
991
992 list_for_each_entry_safe(ck, n, &items, list) {
993 cond_resched();
994
995 list_del(&ck->list);
996 kfree(ck->k);
997 six_lock_exit(&ck->c.lock);
998 kmem_cache_free(bch2_key_cache, ck);
999 }
1000
1001 if (atomic_long_read(&bc->nr_dirty) &&
1002 !bch2_journal_error(&c->journal) &&
1003 test_bit(BCH_FS_WAS_RW, &c->flags))
1004 panic("btree key cache shutdown error: nr_dirty nonzero (%li)\n",
1005 atomic_long_read(&bc->nr_dirty));
1006
1007 if (atomic_long_read(&bc->nr_keys))
1008 panic("btree key cache shutdown error: nr_keys nonzero (%li)\n",
1009 atomic_long_read(&bc->nr_keys));
1010
1011 if (bc->table_init_done)
1012 rhashtable_destroy(&bc->table);
1013
1014 free_percpu(bc->pcpu_freed);
1015 }
1016
1017 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
1018 {
1019 mutex_init(&c->lock);
1020 INIT_LIST_HEAD(&c->freed_pcpu);
1021 INIT_LIST_HEAD(&c->freed_nonpcpu);
1022 }
1023
1024 int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
1025 {
1026 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
1027 struct shrinker *shrink;
1028
1029 #ifdef __KERNEL__
1030 bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
1031 if (!bc->pcpu_freed)
1032 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1033 #endif
1034
1035 if (rhashtable_init(&bc->table, &bch2_btree_key_cache_params))
1036 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1037
1038 bc->table_init_done = true;
1039
1040 shrink = shrinker_alloc(0, "%s-btree_key_cache", c->name);
1041 if (!shrink)
1042 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1043 bc->shrink = shrink;
1044 shrink->seeks = 0;
1045 shrink->count_objects = bch2_btree_key_cache_count;
1046 shrink->scan_objects = bch2_btree_key_cache_scan;
1047 shrink->private_data = c;
1048 shrinker_register(shrink);
1049 return 0;
1050 }
1051
1052 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
1053 {
1054 prt_printf(out, "nr_freed:\t%lu", atomic_long_read(&c->nr_freed));
1055 prt_newline(out);
1056 prt_printf(out, "nr_keys:\t%lu", atomic_long_read(&c->nr_keys));
1057 prt_newline(out);
1058 prt_printf(out, "nr_dirty:\t%lu", atomic_long_read(&c->nr_dirty));
1059 prt_newline(out);
1060 }
1061
1062 void bch2_btree_key_cache_exit(void)
1063 {
1064 kmem_cache_destroy(bch2_key_cache);
1065 }
1066
1067 int __init bch2_btree_key_cache_init(void)
1068 {
1069 bch2_key_cache = KMEM_CACHE(bkey_cached, SLAB_RECLAIM_ACCOUNT);
1070 if (!bch2_key_cache)
1071 return -ENOMEM;
1072
1073 return 0;
1074 }
Mirror https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git