From: Dave Chinner Subject: Re: [PATCH 4/9] xfs: honor the O_SYNC flag for aysnchronous direct I/O requests Date: Wed, 21 Nov 2012 07:08:27 +1100 Message-ID: <20121120200827.GE2591@dastard> References: <20121120074116.24645.36369.stgit@blackbox.djwong.org> <20121120075114.25270.40680.stgit@blackbox.djwong.org> <20121120112038.GC2591@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Darrick J. Wong" , axboe@kernel.dk, tytso@mit.edu, bpm@sgi.com, viro@zeniv.linux.org.uk, jack@suse.cz, linux-fsdevel@vger.kernel.org, hch@infradead.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com, djwong+kernel@djwong.org To: Jeff Moyer Return-path: Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:27736 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752503Ab2KTUIa (ORCPT ); Tue, 20 Nov 2012 15:08:30 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Nov 20, 2012 at 02:42:48PM -0500, Jeff Moyer wrote: > Dave Chinner writes: > > > And requeuing work from one workqueue to the next is something that > > we can avoid. We know at IO submission time (i.e. > > xfs_vm_direct_io)) whether an fsync completion is going to be needed > > during Io completion. The ioend->io_needs_fsync flag can be set > > then, and the first pass through xfs_finish_ioend() can queue it to > > the correct workqueue. i.e. it only needs to be queued if it's not > > already an unwritten or append ioend and it needs an fsync. > > > > As it is, all the data completion workqueues run the same completion > > function so all you need to do is handle the fsync case at the end > > of the existing processing - it's not an else case. i.e the end of > > xfs_end_io() becomes: > > > > if (ioend->io_needs_fsync) { > > error = xfs_ioend_fsync(ioend); > > if (error) > > ioend->io_error = -error; > > goto done; > > } > > done: > > xfs_destroy_ioend(ioend); > > Works for me, that makes things simpler. > > > As it is, this code is going to change before these changes go in - > > there's a nasty regression in the DIO code that I found this > > afternoon that requires reworking this IO completion logic to > > avoid. The patch will appear on the list soon.... > > I'm not on the xfs list, so if you haven't already sent it, mind Cc-ing > me? http://oss.sgi.com/archives/xfs/2012-11/msg00493.html First cut is here, but it will change a bit as review goes on... > >> --- a/fs/xfs/xfs_mount.h > >> +++ b/fs/xfs/xfs_mount.h > >> @@ -209,6 +209,7 @@ typedef struct xfs_mount { > >> struct workqueue_struct *m_data_workqueue; > >> struct workqueue_struct *m_unwritten_workqueue; > >> struct workqueue_struct *m_cil_workqueue; > >> + struct workqueue_struct *m_aio_blkdev_flush_wq; > > > > struct workqueue_struct *m_aio_fsync_wq; > > For the record, m_aio_blkdev_flush_wq is the name you chose previously. > ;-) It's been a long time since I read that patch.... :) Cheers, Dave.... -- Dave Chinner david@fromorbit.com