Commit c2f6e16a authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Increase size of cuckoo hash table on too many rehashes 



Also, improve the calculation of the new table size, so that it can
shrink when needed.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 58474f76

fs/bcachefs/buckets_waiting_for_journal.c

+9 −2
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ int bch2_set_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b, 
		.dev_bucket	= (u64) dev << 56 | bucket,

		.journal_seq	= journal_seq,

	};

	size_t i, size, new_bits, nr_elements = 1, nr_rehashes = 0;

	size_t i, size, new_bits, nr_elements = 1, nr_rehashes = 0, nr_rehashes_this_size = 0;

	int ret = 0;



	mutex_lock(&b->lock);
@@ -106,7 +106,7 @@ int bch2_set_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b, 
	for (i = 0; i < size; i++)

		nr_elements += t->d[i].journal_seq > flushed_seq;



	new_bits = t->bits + (nr_elements * 3 > size);

	new_bits = ilog2(roundup_pow_of_two(nr_elements * 3));



	n = kvmalloc(sizeof(*n) + (sizeof(n->d[0]) << new_bits), GFP_KERNEL);

	if (!n) {
@@ -115,7 +115,14 @@ int bch2_set_bucket_needs_journal_commit(struct buckets_waiting_for_journal *b, 
	}



retry_rehash:

	if (nr_rehashes_this_size == 3) {

		new_bits++;

		nr_rehashes_this_size = 0;

	}



	nr_rehashes++;

	nr_rehashes_this_size++;



	bucket_table_init(n, new_bits);



	tmp = new;