From: Jeff Moyer Subject: [PATCH 4/6] jbd: use WRITE_SYNC for journal I/O Date: Fri, 2 Jul 2010 15:58:17 -0400 Message-ID: <1278100699-24132-5-git-send-email-jmoyer@redhat.com> References: <1278100699-24132-1-git-send-email-jmoyer@redhat.com> Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, vgoyal@redhat.com, tao.ma@oracle.com, Jeff Moyer To: linux-ext4@vger.kernel.org Return-path: In-Reply-To: <1278100699-24132-1-git-send-email-jmoyer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org In my fsync testing, journal I/O most definitely was sync I/O, since another process was blocked waiting for the results. By marking all journal I/O as WRITE_SYNC, I can get better performance with CFQ. If there is a way to mark this only for cases where it is blocking progress in a dependent process, then that would be preferrable. Is there such a means for determining and flagging this? Cheers, Jeff Signed-off-by: Jeff Moyer --- fs/jbd/commit.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c index 28a9dda..d97a0c6 100644 --- a/fs/jbd/commit.c +++ b/fs/jbd/commit.c @@ -317,7 +317,7 @@ void journal_commit_transaction(journal_t *journal) int first_tag = 0; int tag_flag; int i; - int write_op = WRITE; + int write_op = WRITE_SYNC; /* * First job: lock down the current transaction and wait for -- 1.6.5.2