From: Theodore Ts'o <tytso@mit.edu>
To: Ext4 Developers List <linux-ext4@vger.kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Subject: [PATCH 1/6] jbd2: don't hold j_state_lock while calling wake_up()
Date: Sun, 9 Mar 2014 01:05:36 -0500 [thread overview]
Message-ID: <1394345141-3471-1-git-send-email-tytso@mit.edu> (raw)
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 --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
next reply other threads:[~2014-03-09 6:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-09 6:05 Theodore Ts'o [this message]
2014-03-09 6:05 ` [PATCH 2/6] jbd2: calculate statistics without holding j_state_lock and j_list_lock Theodore Ts'o
2014-03-09 6:05 ` [PATCH 3/6] jbd2: add transaction to checkpoint list earlier Theodore Ts'o
2014-03-09 6:05 ` [PATCH 4/6] jbd2: check jh->b_transaction without taking j_list_lock Theodore Ts'o
2014-03-09 6:05 ` [PATCH 5/6] jbd2: minimize region locked by j_list_lock in journal_get_create_access() Theodore Ts'o
2014-03-09 6:05 ` [PATCH 6/6] jbd2: minimize region locked by j_list_lock in jbd2_journal_forget() Theodore Ts'o
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