From patchwork Thu Jan 31 09:39:03 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miao Xie X-Patchwork-Id: 2071801 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 1A6DFDF2E5 for ; Thu, 31 Jan 2013 09:38:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753241Ab3AaJiZ (ORCPT ); Thu, 31 Jan 2013 04:38:25 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:13906 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752950Ab3AaJiW (ORCPT ); Thu, 31 Jan 2013 04:38:22 -0500 X-IronPort-AV: E=Sophos;i="4.84,575,1355068800"; d="scan'208";a="6671471" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 31 Jan 2013 17:36:10 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id r0V9cKno023305; Thu, 31 Jan 2013 17:38:20 +0800 Received: from [10.167.225.199] ([10.167.225.199]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2013013117371207-197156 ; Thu, 31 Jan 2013 17:37:12 +0800 Message-ID: <510A3BB7.4090201@cn.fujitsu.com> Date: Thu, 31 Jan 2013 17:39:03 +0800 From: Miao Xie Reply-To: miaox@cn.fujitsu.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Linux Btrfs CC: Josef Bacik Subject: [RFC][PATCH 2/2] Btrfs: implement unlocked dio write X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/01/31 17:37:12, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/01/31 17:37:12, Serialize complete at 2013/01/31 17:37:12 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This idea is from ext4. By this patch, we can make the dio write parallel, and improve the performance. We needn't worry about the race between dio write and truncate, because the truncate need wait untill all the dio write end. And we also needn't worry about the race between dio write and punch hole, because we have extent lock to protect our operation. I ran fio to test the performance of this feature. == Hardware == CPU: Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz Mem: 2GB SSD: Intel X25-M 120GB (Test Partition: 60GB) == config file == [global] ioengine=psync direct=1 bs=4k size=32G runtime=60 directory=/mnt/btrfs/ filename=testfile group_reporting thread [file1] numjobs=1 # 2 4 rw=randwrite == result (KBps) == write 1 2 4 lock 24936 24738 24726 nolock 24962 30866 32101 == result (iops) == write 1 2 4 lock 6234 6184 6181 nolock 6240 7716 8025 Signed-off-by: Miao Xie --- fs/btrfs/inode.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index d17a04b..091593a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6589,31 +6589,33 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb, struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; int flags = 0; - bool wakeup = false; + bool wakeup = true; int ret; if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov, offset, nr_segs)) return 0; - if (rw == READ) { - atomic_inc(&inode->i_dio_count); - smp_mb__after_atomic_inc(); - if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK, - &BTRFS_I(inode)->runtime_flags))) { - inode_dio_done(inode); - flags = DIO_LOCKING | DIO_SKIP_HOLES; - } else { - wakeup = true; - } + atomic_inc(&inode->i_dio_count); + smp_mb__after_atomic_inc(); + if (rw == WRITE) { + mutex_unlock(&inode->i_mutex); + } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK, + &BTRFS_I(inode)->runtime_flags))) { + inode_dio_done(inode); + flags = DIO_LOCKING | DIO_SKIP_HOLES; + wakeup = false; } ret = __blockdev_direct_IO(rw, iocb, inode, BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev, iov, offset, nr_segs, btrfs_get_blocks_direct, NULL, btrfs_submit_direct, flags); + if (wakeup) inode_dio_done(inode); + if (rw == WRITE) + mutex_lock(&inode->i_mutex); return ret; }