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[1/6] jbd2: don't hold j_state_lock while calling wake_up()

Message ID 1394345141-3471-1-git-send-email-tytso@mit.edu
State Accepted, archived
Headers show

Commit Message

Theodore Ts'o March 9, 2014, 6:05 a.m. UTC 
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@mit.edu>
---
 fs/jbd2/journal.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox

Patch

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);