jbd2: add transaction to checkpoint list earlier

We don't otherwise need j_list_lock during the rest of commit phase
#7, so add the transaction to the checkpoint list at the very end of
commit phase #6.  This allows us to drop j_list_lock earlier, which is
a good thing since it is a super hot lock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2014-03-08 22:34:10 -05:00
parent 42cf3452d5
commit d4e839d4a9

View File

@ -1065,6 +1065,25 @@ restart_loop:
goto restart_loop;
}
/* Add the transaction to the checkpoint list
* __journal_remove_checkpoint() can not destroy transaction
* under us because it is not marked as T_FINISHED yet */
if (journal->j_checkpoint_transactions == NULL) {
journal->j_checkpoint_transactions = commit_transaction;
commit_transaction->t_cpnext = commit_transaction;
commit_transaction->t_cpprev = commit_transaction;
} else {
commit_transaction->t_cpnext =
journal->j_checkpoint_transactions;
commit_transaction->t_cpprev =
commit_transaction->t_cpnext->t_cpprev;
commit_transaction->t_cpnext->t_cpprev =
commit_transaction;
commit_transaction->t_cpprev->t_cpnext =
commit_transaction;
}
spin_unlock(&journal->j_list_lock);
/* Done with this transaction! */
jbd_debug(3, "JBD2: commit phase 7\n");
@ -1103,24 +1122,6 @@ restart_loop:
write_unlock(&journal->j_state_lock);
if (journal->j_checkpoint_transactions == NULL) {
journal->j_checkpoint_transactions = commit_transaction;
commit_transaction->t_cpnext = commit_transaction;
commit_transaction->t_cpprev = commit_transaction;
} else {
commit_transaction->t_cpnext =
journal->j_checkpoint_transactions;
commit_transaction->t_cpprev =
commit_transaction->t_cpnext->t_cpprev;
commit_transaction->t_cpnext->t_cpprev =
commit_transaction;
commit_transaction->t_cpprev->t_cpnext =
commit_transaction;
}
spin_unlock(&journal->j_list_lock);
/* Drop all spin_locks because commit_callback may be block.
* __journal_remove_checkpoint() can not destroy transaction
* under us because it is not marked as T_FINISHED yet */
if (journal->j_commit_callback)
journal->j_commit_callback(journal, commit_transaction);
@ -1131,7 +1132,7 @@ restart_loop:
write_lock(&journal->j_state_lock);
spin_lock(&journal->j_list_lock);
commit_transaction->t_state = T_FINISHED;
/* Recheck checkpoint lists after j_list_lock was dropped */
/* Check if the transaction can be dropped now that we are finished */
if (commit_transaction->t_checkpoint_list == NULL &&
commit_transaction->t_checkpoint_io_list == NULL) {
__jbd2_journal_drop_transaction(journal, commit_transaction);