From patchwork Wed Dec 19 02:59:54 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: jbd2: don't wake kjournald unnecessarily Date: Tue, 18 Dec 2012 16:59:54 -0000 From: Eric Sandeen X-Patchwork-Id: 207237 Message-Id: <50D12DAA.9050700@redhat.com> To: ext4 development , Jan Kara Cc: Dave Wysochanski Don't send an extra wakeup to kjournald in the case where we already have the proper target in j_commit_request, i.e. that transaction has already been requested for commit. commit deeeaf13 "jbd2: fix fsync() tid wraparound bug" changed the logic leading to a wakeup, but it caused some extra wakeups which were found to lead to a measurable performance regression. Signed-off-by: Eric Sandeen --- -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index dbf41f9..89970d5 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -518,7 +518,8 @@ int __jbd2_log_start_commit(journal_t *journal, tid_t target) * currently running transaction (if it exists). Otherwise, * the target tid must be an old one. */ - if (journal->j_running_transaction && + if (journal->j_commit_request != target && + journal->j_running_transaction && journal->j_running_transaction->t_tid == target) { /* * We want a new commit: OK, mark the request and wakeup the