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Commit 3469a32a authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

jbd2: don't hold j_state_lock while calling wake_up() 



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: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent df3c1e9a

fs/jbd2/journal.c

+2 −2
Original line number Diff line number Diff line
@@ -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);