The j_state_lock is one of the hottest locks in the jbd2 layer and
thus one of its scalability bottlenecks.
We don't need to be holding the j_state_lock while we are calling
wake_up(&journal->j_wait_commit), so release the lock a little bit
earlier.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
fs/jbd2/journal.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 244b6f6..67b8e30 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -302,8 +302,8 @@ static void journal_kill_thread(journal_t *journal)
journal->j_flags |= JBD2_UNMOUNT;
while (journal->j_task) {
- wake_up(&journal->j_wait_commit);
write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_commit);
wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
write_lock(&journal->j_state_lock);
}
@@ -710,8 +710,8 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
while (tid_gt(tid, journal->j_commit_sequence)) {
jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
tid, journal->j_commit_sequence);
- wake_up(&journal->j_wait_commit);
read_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_commit);
wait_event(journal->j_wait_done_commit,
!tid_gt(tid, journal->j_commit_sequence));
read_lock(&journal->j_state_lock);
--
1.9.0
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