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From: ira.weiny@intel.com
To: linux-kernel@vger.kernel.org
Cc: Ira Weiny <ira.weiny@intel.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>,
	Christoph Hellwig <hch@lst.de>,
	"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
	linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH 0/5] Enable per-file/directory DAX operations
Date: Sun, 20 Oct 2019 08:59:30 -0700	[thread overview]
Message-ID: <20191020155935.12297-1-ira.weiny@intel.com> (raw)

From: Ira Weiny <ira.weiny@intel.com>

At LSF/MM'19 [1] [2] we discussed applications that overestimate memory
consumption due to their inability to detect whether the kernel will
instantiate page cache for a file, and cases where a global dax enable via a
mount option is too coarse.

The following patch series enables selecting the use of DAX on individual files
and/or directories on xfs, and lays some groundwork to do so in ext4.  In this
scheme the dax mount option can be omitted to allow the per-file property to
take effect.

The insight at LSF/MM was to separate the per-mount or per-file "physical"
capability switch from an "effective" attribute for the file.

At LSF/MM we discussed the difficulties of switching the mode of a file with
active mappings / page cache. Rather than solve those races the decision was to
just limit mode flips to 0-length files.

Finally, the physical DAX flag inheritance is maintained from previous work on 
XFS but should be added for other file systems for consistence.


[1] https://lwn.net/Articles/787973/
[2] https://lwn.net/Articles/787233/

To: linux-kernel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Cc: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org

Ira Weiny (5):
  fs/stat: Define DAX statx attribute
  fs/xfs: Isolate the physical DAX flag from effective
  fs/xfs: Separate functionality of xfs_inode_supports_dax()
  fs/xfs: Clean up DAX support check
  fs/xfs: Allow toggle of physical DAX flag

 fs/stat.c                 |  3 +++
 fs/xfs/xfs_ioctl.c        | 32 ++++++++++++++------------------
 fs/xfs/xfs_iops.c         | 36 ++++++++++++++++++++++++++++++------
 fs/xfs/xfs_iops.h         |  2 ++
 include/uapi/linux/stat.h |  1 +
 5 files changed, 50 insertions(+), 24 deletions(-)

-- 
2.20.1


             reply	other threads:[~2019-10-20 15:59 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-20 15:59 ira.weiny [this message]
2019-10-20 15:59 ` [PATCH 1/5] fs/stat: Define DAX statx attribute ira.weiny
2019-10-22 11:32   ` Boaz Harrosh
2019-10-22 16:51     ` Ira Weiny
2019-10-20 15:59 ` [PATCH 2/5] fs/xfs: Isolate the physical DAX flag from effective ira.weiny
2019-10-21  0:26   ` Dave Chinner
2019-10-21 17:40     ` Ira Weiny
2019-10-20 15:59 ` [PATCH 3/5] fs/xfs: Separate functionality of xfs_inode_supports_dax() ira.weiny
2019-10-20 15:59 ` [PATCH 4/5] fs/xfs: Clean up DAX support check ira.weiny
2019-10-20 15:59 ` [PATCH 5/5] fs/xfs: Allow toggle of physical DAX flag ira.weiny
2019-10-21  0:45   ` Dave Chinner
2019-10-21 22:49     ` Ira Weiny
2019-10-21 23:46       ` Dave Chinner
2019-11-08 13:12       ` Jan Kara
2019-11-08 13:46         ` Jan Kara
2019-11-08 19:36           ` Ira Weiny
2019-11-11 16:07             ` Jan Kara
2019-11-11 23:54               ` Ira Weiny
2019-10-22 11:21 ` [PATCH 0/5] Enable per-file/directory DAX operations Boaz Harrosh
2019-10-23 13:09   ` Boaz Harrosh
2019-10-23 22:13     ` Dave Chinner
2019-10-24  2:31       ` Boaz Harrosh
2019-10-24  7:34         ` Dave Chinner
2019-10-24 14:05           ` Boaz Harrosh
2019-10-24 21:35             ` Dave Chinner
2019-10-24 23:29               ` Boaz Harrosh
2019-10-25  0:36                 ` Dave Chinner
2019-10-25  1:15                   ` Boaz Harrosh
2019-10-25 20:49                   ` Ira Weiny
2019-10-27 22:10                     ` Dave Chinner
2019-10-31 16:17                       ` Ira Weiny
2019-11-01 22:47                         ` Dave Chinner
2019-11-02  4:25                           ` Dan Williams

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