| Message ID | c1424ac2e6f6f5a21bcf2fb7679203df865c8a60.1642953021.git.riteshh@linux.ibm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | jbd2: Kill age-old t_handle_lock transaction spinlock | expand |
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@linux.ibm.com> Sounds fine. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> 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 >
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 } /*
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@linux.ibm.com> --- fs/jbd2/transaction.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) -- 2.31.1