On Sun 23-01-22 22:53:28, Ritesh Harjani wrote:
> CONFIG_JBD2_DEBUG and jbd2_journal_enable_debug knobs were added in
> update_t_max_wait(), since earlier it used to take a spinlock for updating
> t_max_wait, which could cause a bottleneck while starting a txn
> (start_this_handle()).
> Since in previous patch, we have killed t_handle_lock completely, we
> could get rid of this debug config and knob to let t_max_wait be updated
> by default again.
>
> Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
Sounds fine. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/jbd2/transaction.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> index 68dd7de49aff..77634e2e118e 100644
> --- a/fs/jbd2/transaction.c
> +++ b/fs/jbd2/transaction.c
> @@ -141,20 +141,19 @@ static void jbd2_get_transaction(journal_t *journal,
> * t_max_wait is carefully updated here with use of atomic compare exchange.
> * Note that there could be multiplre threads trying to do this simultaneously
> * hence using cmpxchg to avoid any use of locks in this case.
> + * With this t_max_wait can be updated w/o enabling jbd2_journal_enable_debug.
> */
> static inline void update_t_max_wait(transaction_t *transaction,
> unsigned long ts)
> {
> -#ifdef CONFIG_JBD2_DEBUG
> unsigned long oldts, newts;
> - if (jbd2_journal_enable_debug &&
> - time_after(transaction->t_start, ts)) {
> +
> + if (time_after(transaction->t_start, ts)) {
> newts = jbd2_time_diff(ts, transaction->t_start);
> oldts = READ_ONCE(transaction->t_max_wait);
> while (oldts < newts)
> oldts = cmpxchg(&transaction->t_max_wait, oldts, newts);
> }
> -#endif
> }
>
> /*
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
