From c2f6e16a6771eaefba6bb35f6803fe7217822d41 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Thu, 15 Aug 2024 13:02:55 -0400
Subject: [PATCH] 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: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/buckets_waiting_for_journal.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/bcachefs/buckets_waiting_for_journal.c b/fs/bcachefs/buckets_waiting_for_journal.c
index ec1b636ef78d0..f70eb2127d322 100644
--- a/fs/bcachefs/buckets_waiting_for_journal.c
+++ b/fs/bcachefs/buckets_waiting_for_journal.c
@@ -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;
--
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