jbd2: 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>
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 4ea7237..073c8c3 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -138,7 +138,7 @@
set_buffer_ordered(bh);
barrier_done = 1;
}
- ret = submit_bh(WRITE_SYNC, bh);
+ ret = submit_bh(WRITE_SYNC_PLUG, bh);
if (barrier_done)
clear_buffer_ordered(bh);
@@ -159,7 +159,7 @@
lock_buffer(bh);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
- ret = submit_bh(WRITE_SYNC, bh);
+ ret = submit_bh(WRITE_SYNC_PLUG, bh);
}
*cbh = bh;
return ret;
@@ -190,7 +190,7 @@
set_buffer_uptodate(bh);
bh->b_end_io = journal_end_buffer_io_sync;
- ret = submit_bh(WRITE_SYNC, bh);
+ ret = submit_bh(WRITE_SYNC_PLUG, bh);
if (ret) {
unlock_buffer(bh);
return ret;
@@ -402,8 +402,13 @@
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;
stats.u.run.rs_wait = commit_transaction->t_max_wait;
stats.u.run.rs_locked = jiffies;
stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start,