From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id E2ACE7F55 for ; Tue, 14 Apr 2015 02:27:02 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay1.corp.sgi.com (Postfix) with ESMTP id D2A408F804B for ; Tue, 14 Apr 2015 00:26:59 -0700 (PDT) Received: from ipmail06.adl6.internode.on.net (ipmail06.adl6.internode.on.net [150.101.137.145]) by cuda.sgi.com with ESMTP id 3yckzXhiClItYbYa for ; Tue, 14 Apr 2015 00:26:57 -0700 (PDT) Received: from disappointment.disaster.area ([192.168.1.110] helo=disappointment) by dastard with esmtp (Exim 4.80) (envelope-from ) id 1YhvFF-0000qg-0F for xfs@oss.sgi.com; Tue, 14 Apr 2015 17:26:53 +1000 Received: from dave by disappointment with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1YhvFE-0000W3-Vk for xfs@oss.sgi.com; Tue, 14 Apr 2015 17:26:52 +1000 From: Dave Chinner Subject: [PATCH 8/8] xfs: using generic_file_direct_write() is unnecessary Date: Tue, 14 Apr 2015 17:26:51 +1000 Message-Id: <1428996411-1507-9-git-send-email-david@fromorbit.com> In-Reply-To: <1428996411-1507-1-git-send-email-david@fromorbit.com> References: <1428996411-1507-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com From: Dave Chinner generic_file_direct_write() does all sorts of things to make DIO work "sorta ok" with mixed buffered IO workloads. We already do most of this work in xfs_file_aio_dio_write() because of the locking requirements, so there's only a couple of things it does for us. The first thing is that it does a page cache invalidation after the ->direct_IO callout. This can easily be added to the XFS code. The second thing it does is that if data was written, it updates the iov_iter structure to reflect the data written, and then does EOF size updates if necessary. For XFS, these EOF size updates are now not necessary, as we do them safely and race-free in IO completion context. That leaves just the iov_iter update, and that's also moved to the XFS code. Therefore we don't need to call generic_file_direct_write() and in doing so remove redundant buffered writeback and page cache invalidation calls from the DIO submission path. We also remove a racy EOF size update, and make the DIO submission code in XFS much easier to follow. Wins all round, really. Signed-off-by: Dave Chinner --- fs/xfs/xfs_file.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index c398ec7..3a5d305 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -665,6 +665,8 @@ xfs_file_dio_aio_write( int iolock; size_t count = iov_iter_count(from); loff_t pos = iocb->ki_pos; + loff_t end; + struct iov_iter data; struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ? mp->m_rtdev_targp : mp->m_ddev_targp; @@ -704,10 +706,11 @@ xfs_file_dio_aio_write( if (ret) goto out; iov_iter_truncate(from, count); + end = pos + count - 1; if (mapping->nrpages) { ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, - pos, pos + count - 1); + pos, end); if (ret) goto out; /* @@ -717,7 +720,7 @@ xfs_file_dio_aio_write( */ ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, pos >> PAGE_CACHE_SHIFT, - (pos + count - 1) >> PAGE_CACHE_SHIFT); + end >> PAGE_CACHE_SHIFT); WARN_ON_ONCE(ret); ret = 0; } @@ -734,8 +737,22 @@ xfs_file_dio_aio_write( } trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0); - ret = generic_file_direct_write(iocb, from, pos); + data = *from; + ret = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos); + + /* see generic_file_direct_write() for why this is necessary */ + if (mapping->nrpages) { + invalidate_inode_pages2_range(mapping, + pos >> PAGE_CACHE_SHIFT, + end >> PAGE_CACHE_SHIFT); + } + + if (ret > 0) { + pos += ret; + iov_iter_advance(from, ret); + iocb->ki_pos = pos; + } out: xfs_rw_iunlock(ip, iolock); -- 2.0.0 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs