On 2024/7/1 21:28, Jan Kara wrote:
> Originally, we were quite conservative in limiting maximum transaction
> size to a quarter of the journal because we were not accounting
> transaction descriptor and revoke blocks. These days we do properly
> account them and reserve space for them from the total transaction
> credits. Thus there's no need to be so conservative and we can increase
> the maximum transaction size to one third of the journal (even half
> should work fine in principle but the performance will likely suffer in
> that case). This also fixes failures to grow filesystems with tiny
> journals.
>
This looks straightforward and reasonable to me. I've done some metadata
intensive performance tests with fs_mark, no obvious degradation and
fluctuation has been found.
Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Thanks,
Yi.
> Link: CA+hUFcuGs04JHZ_WzA1zGN57+ehL2qmHOt5a7RMpo+rv6Vyxtw@xxxxxxxxxxxxxx
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> include/linux/jbd2.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index ab04c1c27fae..7273ef1732bf 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1662,7 +1662,7 @@ int jbd2_fc_release_bufs(journal_t *journal);
>
> static inline int jbd2_journal_get_max_txn_bufs(journal_t *journal)
> {
> - return (journal->j_total_len - journal->j_fc_wbufsize) / 4;
> + return (journal->j_total_len - journal->j_fc_wbufsize) / 3;
> }
>
> /*
>
