From 6c4bac6b3351fd278dc3537dae42f88f733ff12e Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Mon, 6 Apr 2009 14:48:04 +0200
Subject: [PATCH] jbd: use WRITE_SYNC_PLUG instead of WRITE_SYNC
When you are going to be submitting several sync writes, we want to
give the IO scheduler a chance to merge some of them. Instead of
using the implicitly unplugging WRITE_SYNC variant, use WRITE_SYNC_PLUG
and rely on sync_buffer() doing the unplug when someone does a
wait_on_buffer()/lock_buffer().
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/jbd/commit.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index f8077b9c89816..a8e8513a78a94 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -351,8 +351,13 @@ void journal_commit_transaction(journal_t *journal)
spin_lock(&journal->j_state_lock);
commit_transaction->t_state = T_LOCKED;
+ /*
+ * Use plugged writes here, since we want to submit several before
+ * we unplug the device. We don't do explicit unplugging in here,
+ * instead we rely on sync_buffer() doing the unplug for us.
+ */
if (commit_transaction->t_synchronous_commit)
- write_op = WRITE_SYNC;
+ write_op = WRITE_SYNC_PLUG;
spin_lock(&commit_transaction->t_handle_lock);
while (commit_transaction->t_updates) {
DEFINE_WAIT(wait);
--
GitLab