From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@lst.de>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC PATCH V2 01/12] fs/stat: Define DAX statx attribute
Date: Thu, 16 Jan 2020 14:19:06 -0800 [thread overview]
Message-ID: <20200116221906.GF8247@magnolia> (raw)
In-Reply-To: <20200116185235.GE24522@iweiny-DESK2.sc.intel.com>
On Thu, Jan 16, 2020 at 10:52:36AM -0800, Ira Weiny wrote:
> On Thu, Jan 16, 2020 at 10:04:21AM -0800, Darrick J. Wong wrote:
> > On Thu, Jan 16, 2020 at 09:55:02AM -0800, Ira Weiny wrote:
> > > On Wed, Jan 15, 2020 at 09:39:35PM -0800, Darrick J. Wong wrote:
> > > > On Wed, Jan 15, 2020 at 02:38:21PM -0800, Ira Weiny wrote:
> > > > > On Wed, Jan 15, 2020 at 12:10:50PM -0800, Dan Williams wrote:
> > > > > > On Wed, Jan 15, 2020 at 11:45 AM Ira Weiny <ira.weiny@intel.com> wrote:
> > > > > > >
> > > > > > > On Wed, Jan 15, 2020 at 09:38:34AM -0800, Darrick J. Wong wrote:
> > > > > > > > On Wed, Jan 15, 2020 at 12:37:15PM +0100, Jan Kara wrote:
> > > > > > > > > On Fri 10-01-20 11:29:31, ira.weiny@intel.com wrote:
> > > > > > > > > > From: Ira Weiny <ira.weiny@intel.com>
> > > > > > > > > >
> > > > >
> > >
> > > [snip]
> > >
> > > > >
> > > > > Sure, but for now I think referencing mmap for details on MAP_SYNC works.
> > > > >
> > > > > I suspect that we may have some word smithing once I get this series in and we
> > > > > submit a change to the statx man page itself. Can I move forward with the
> > > > > following for this patch?
> > > > >
> > > > > <quote>
> > > > > STATX_ATTR_DAX
> > > > >
> > > > > The file is in the DAX (cpu direct access) state. DAX state
> > > >
> > > > Hmm, now that I see it written out, I <cough> kind of like "DAX mode"
> > > > better now. :/
> > > >
> > > > "The file is in DAX (CPU direct access) mode. DAX mode attempts..."
> > >
> > > Sure... now you tell me... ;-)
> > >
> > > Seriously, we could use mode here in the man page as this is less confusing to
> > > say "DAX mode".
> > >
> > > But I think the code should still use 'state' because mode is just too
> > > overloaded. You were not the only one who was thrown by my use of mode and I
> > > don't want that confusion when we look at this code 2 weeks from now...
> > >
> > > https://www.reddit.com/r/ProgrammerHumor/comments/852og2/only_god_knows/
> > >
> > > ;-)
> >
> > Ok, let's leave it alone for now then.
>
> Cool could I get a reviewed by?
My bike shed is painted green with purple polka dots,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
--D
> And Jan is this reword of the man page/commit ok to keep your reviewed by?
>
> >
> > I'm not even sure what 'DAX' stands for. Direct Access to ...
> > Professor Xavier? 8-)
>
> That is pronounced 'Direct A'Xes' you know, for chopping wood!
>
> Thanks everyone,
> Ira
>
> >
> > > >
> > > > > attempts to minimize software cache effects for both I/O and
> > > > > memory mappings of this file. It requires a file system which
> > > > > has been configured to support DAX.
> > > > >
> > > > > DAX generally assumes all accesses are via cpu load / store
> > > > > instructions which can minimize overhead for small accesses, but
> > > > > may adversely affect cpu utilization for large transfers.
> > > > >
> > > > > File I/O is done directly to/from user-space buffers and memory
> > > > > mapped I/O may be performed with direct memory mappings that
> > > > > bypass kernel page cache.
> > > > >
> > > > > While the DAX property tends to result in data being transferred
> > > > > synchronously, it does not give the same guarantees of
> > > > > synchronous I/O where data and the necessary metadata are
> > > > > transferred together.
> > > >
> > > > (I'm frankly not sure that synchronous I/O actually guarantees that the
> > > > metadata has hit stable storage...)
> > >
> > > I'll let you and Dan work this one out... ;-)
> >
> > Hehe. I think the wording here is fine.
> >
> > --D
> >
> > > Ira
> > >
next prev parent reply other threads:[~2020-01-16 22:19 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 19:29 [RFC PATCH V2 00/12] Enable per-file/directory DAX operations V2 ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 01/12] fs/stat: Define DAX statx attribute ira.weiny
2020-01-15 11:37 ` Jan Kara
2020-01-15 17:38 ` Darrick J. Wong
2020-01-15 19:45 ` Ira Weiny
2020-01-15 20:10 ` Dan Williams
2020-01-15 22:38 ` Ira Weiny
2020-01-16 5:39 ` Darrick J. Wong
2020-01-16 6:05 ` Dan Williams
2020-01-16 6:18 ` Darrick J. Wong
2020-01-16 6:25 ` Dan Williams
2020-01-18 9:11 ` Dave Chinner
2020-01-16 17:55 ` Ira Weiny
2020-01-16 18:04 ` Darrick J. Wong
2020-01-16 18:52 ` Ira Weiny
2020-01-16 22:19 ` Darrick J. Wong [this message]
2020-01-17 11:58 ` Jan Kara
2020-01-10 19:29 ` [RFC PATCH V2 02/12] fs/xfs: Isolate the physical DAX flag from effective ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 03/12] fs/xfs: Separate functionality of xfs_inode_supports_dax() ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 04/12] fs/xfs: Clean up DAX support check ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 05/12] fs: remove unneeded IS_DAX() check ira.weiny
2020-01-16 9:38 ` Jan Kara
2020-01-16 18:47 ` Ira Weiny
2020-01-10 19:29 ` [RFC PATCH V2 06/12] fs/xfs: Check if the inode supports DAX under lock ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 07/12] fs: Add locking for a dynamic inode 'mode' ira.weiny
2020-01-13 22:12 ` Darrick J. Wong
2020-01-14 0:20 ` Ira Weiny
2020-01-14 1:03 ` Darrick J. Wong
2020-01-15 19:08 ` Ira Weiny
2020-01-16 5:40 ` Darrick J. Wong
2020-01-16 18:54 ` Ira Weiny
2020-01-10 19:29 ` [RFC PATCH V2 08/12] fs/xfs: Add lock/unlock mode to xfs ira.weiny
2020-01-13 22:19 ` Darrick J. Wong
2020-01-14 0:35 ` Ira Weiny
2020-01-15 0:57 ` Ira Weiny
2020-01-15 23:52 ` Ira Weiny
2020-01-16 9:24 ` Jan Kara
2020-01-16 19:12 ` Ira Weiny
2020-01-10 19:29 ` [RFC PATCH V2 09/12] fs: Prevent mode change if file is mmap'ed ira.weiny
2020-01-13 22:22 ` Darrick J. Wong
2020-01-14 0:46 ` Ira Weiny
2020-01-14 1:30 ` Darrick J. Wong
2020-01-14 17:53 ` Ira Weiny
2020-01-15 11:34 ` Jan Kara
2020-01-15 18:24 ` Ira Weiny
2020-01-15 10:21 ` David Laight
2020-01-15 17:53 ` Ira Weiny
2020-01-10 19:29 ` [RFC PATCH V2 10/12] fs/xfs: Fix truncate up ira.weiny
2020-01-13 22:27 ` Darrick J. Wong
2020-01-14 0:40 ` Ira Weiny
2020-01-14 1:14 ` Darrick J. Wong
2020-01-14 19:00 ` Ira Weiny
2020-01-14 19:39 ` Ira Weiny
2020-01-10 19:29 ` [RFC PATCH V2 11/12] fs/xfs: Clean up locking in dax invalidate ira.weiny
2020-01-10 19:29 ` [RFC PATCH V2 12/12] fs/xfs: Allow toggle of effective DAX flag ira.weiny
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