From: Dave Chinner <david@fromorbit.com>
To: Raphael Carvalho <raphael.scarv@gmail.com>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Avi Kivity <avi@scylladb.com>,
andres@anarazel.de
Subject: Re: [RFC] xfs: reduce sub-block DIO serialisation
Date: Mon, 18 Jan 2021 08:36:13 +1100 [thread overview]
Message-ID: <20210117213613.GC78941@dread.disaster.area> (raw)
In-Reply-To: <CACz=WechdgSnVHQsg0LKjMiG8kHLujBshmc270yrdjxfpffmDQ@mail.gmail.com>
On Fri, Jan 15, 2021 at 03:45:14PM -0300, Raphael Carvalho wrote:
> On Tue, Jan 12, 2021 at 7:46 AM Dave Chinner <david@fromorbit.com> wrote:
>
> > Hi folks,
> >
> > This is the XFS implementation on the sub-block DIO optimisations
> > for written extents that I've mentioned on #xfs and a couple of
> > times now on the XFS mailing list.
> >
> > It takes the approach of using the IOMAP_NOWAIT non-blocking
> > IO submission infrastructure to optimistically dispatch sub-block
> > DIO without exclusive locking. If the extent mapping callback
> > decides that it can't do the unaligned IO without extent
> > manipulation, sub-block zeroing, blocking or splitting the IO into
> > multiple parts, it aborts the IO with -EAGAIN. This allows the high
> > level filesystem code to then take exclusive locks and resubmit the
> > IO once it has guaranteed no other IO is in progress on the inode
> > (the current implementation).
> >
>
> I like this optimistic approach very much. One question though: If
> application submits IO with RWF_NOWAIT, then this fallback step will be
> avoided and application will receive EAGAIN, right?
Yes, all the proposed patches do this correctly.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
prev parent reply other threads:[~2021-01-17 21:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 1:07 [RFC] xfs: reduce sub-block DIO serialisation Dave Chinner
2021-01-12 1:07 ` [PATCH 1/6] iomap: convert iomap_dio_rw() to an args structure Dave Chinner
2021-01-12 1:22 ` Damien Le Moal
2021-01-12 1:40 ` Darrick J. Wong
2021-01-12 1:53 ` Dave Chinner
2021-01-12 10:31 ` Christoph Hellwig
2021-01-12 1:07 ` [PATCH 2/6] iomap: move DIO NOWAIT setup up into filesystems Dave Chinner
2021-01-12 1:07 ` [PATCH 3/6] xfs: factor out a xfs_ilock_iocb helper Dave Chinner
2021-01-12 1:07 ` [PATCH 4/6] xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware Dave Chinner
2021-01-12 1:07 ` [PATCH 5/6] xfs: split unaligned DIO write code out Dave Chinner
2021-01-12 10:37 ` Christoph Hellwig
2021-01-12 1:07 ` [PATCH 6/6] xfs: reduce exclusive locking on unaligned dio Dave Chinner
2021-01-12 10:42 ` Christoph Hellwig
2021-01-12 17:01 ` Brian Foster
2021-01-12 17:10 ` Christoph Hellwig
2021-01-12 22:06 ` Dave Chinner
2021-01-12 8:01 ` [RFC] xfs: reduce sub-block DIO serialisation Avi Kivity
2021-01-12 22:13 ` Dave Chinner
2021-01-13 8:00 ` Avi Kivity
2021-01-13 20:38 ` Dave Chinner
2021-01-14 6:48 ` Avi Kivity
2021-01-17 21:34 ` Dave Chinner
2021-01-18 7:41 ` Avi Kivity
[not found] ` <CACz=WechdgSnVHQsg0LKjMiG8kHLujBshmc270yrdjxfpffmDQ@mail.gmail.com>
2021-01-17 21:36 ` Dave Chinner [this message]
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