1 // SPDX-License-Identifier: GPL-2.0
4 #include "buckets_waiting_for_journal.h"
5 #include <linux/hash.h>
6 #include <linux/random.h>
8 static inline struct bucket_hashed *
9 bucket_hash(struct buckets_waiting_for_journal_table *t,
10 unsigned hash_seed_idx, u64 dev_bucket)
12 return t->d + hash_64(dev_bucket ^ t->hash_seeds[hash_seed_idx], t->bits);
15 static void bucket_table_init(struct buckets_waiting_for_journal_table *t, size_t bits)
20 for (i = 0; i < ARRAY_SIZE(t->hash_seeds); i++)
21 get_random_bytes(&t->hash_seeds[i], sizeof(t->hash_seeds[i]));
22 memset(t->d, 0, sizeof(t->d[0]) << t->bits);
25 bool bch2_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b,
27 unsigned dev, u64 bucket)
29 struct buckets_waiting_for_journal_table *t;
30 u64 dev_bucket = (u64) dev << 56 | bucket;
37 for (i = 0; i < ARRAY_SIZE(t->hash_seeds); i++) {
38 struct bucket_hashed *h = bucket_hash(t, i, dev_bucket);
40 if (h->dev_bucket == dev_bucket) {
41 ret = h->journal_seq > flushed_seq;
46 mutex_unlock(&b->lock);
51 static bool bucket_table_insert(struct buckets_waiting_for_journal_table *t,
52 struct bucket_hashed *new,
55 struct bucket_hashed *last_evicted = NULL;
58 for (tries = 0; tries < 10; tries++) {
59 struct bucket_hashed *old, *victim = NULL;
61 for (i = 0; i < ARRAY_SIZE(t->hash_seeds); i++) {
62 old = bucket_hash(t, i, new->dev_bucket);
64 if (old->dev_bucket == new->dev_bucket ||
65 old->journal_seq <= flushed_seq) {
70 if (last_evicted != old)
74 /* hashed to same slot 3 times: */
78 /* Failed to find an empty slot: */
80 last_evicted = victim;
86 int bch2_set_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b,
88 unsigned dev, u64 bucket,
91 struct buckets_waiting_for_journal_table *t, *n;
92 struct bucket_hashed tmp, new = {
93 .dev_bucket = (u64) dev << 56 | bucket,
94 .journal_seq = journal_seq,
96 size_t i, size, new_bits, nr_elements = 1, nr_rehashes = 0;
101 if (likely(bucket_table_insert(b->t, &new, flushed_seq)))
105 size = 1UL << t->bits;
106 for (i = 0; i < size; i++)
107 nr_elements += t->d[i].journal_seq > flushed_seq;
109 new_bits = t->bits + (nr_elements * 3 > size);
111 n = kvmalloc(sizeof(*n) + (sizeof(n->d[0]) << new_bits), GFP_KERNEL);
113 ret = -BCH_ERR_ENOMEM_buckets_waiting_for_journal_set;
119 bucket_table_init(n, new_bits);
122 BUG_ON(!bucket_table_insert(n, &tmp, flushed_seq));
124 for (i = 0; i < 1UL << t->bits; i++) {
125 if (t->d[i].journal_seq <= flushed_seq)
129 if (!bucket_table_insert(n, &tmp, flushed_seq))
136 pr_debug("took %zu rehashes, table at %zu/%lu elements",
137 nr_rehashes, nr_elements, 1UL << b->t->bits);
139 mutex_unlock(&b->lock);
144 void bch2_fs_buckets_waiting_for_journal_exit(struct bch_fs *c)
146 struct buckets_waiting_for_journal *b = &c->buckets_waiting_for_journal;
151 #define INITIAL_TABLE_BITS 3
153 int bch2_fs_buckets_waiting_for_journal_init(struct bch_fs *c)
155 struct buckets_waiting_for_journal *b = &c->buckets_waiting_for_journal;
157 mutex_init(&b->lock);
159 b->t = kvmalloc(sizeof(*b->t) +
160 (sizeof(b->t->d[0]) << INITIAL_TABLE_BITS), GFP_KERNEL);
162 return -BCH_ERR_ENOMEM_buckets_waiting_for_journal_init;
164 bucket_table_init(b->t, INITIAL_TABLE_BITS);