bcachefs: Allocate some extra room in btree_key_cache_fill()

If we allocate a buffer that's a bit bigger than necessary the
transaction commit path will be much less likely to have to reallocate -
which requires a transaction restart.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet 2022-04-17 17:50:47 -04:00 committed by Kent Overstreet
parent b0babf2a34
commit a729e489ab

View file

@ -236,6 +236,13 @@ static int btree_key_cache_fill(struct btree_trans *trans,
*/
new_u64s = k.k->u64s + 1;
/*
* Allocate some extra space so that the transaction commit path is less
* likely to have to reallocate, since that requires a transaction
* restart:
*/
new_u64s = min(256U, (new_u64s * 3) / 2);
if (new_u64s > ck->u64s) {
new_u64s = roundup_pow_of_two(new_u64s);
new_k = kmalloc(new_u64s * sizeof(u64), GFP_NOFS);