From: Ira Weiny <ira.weiny@intel.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: linux-kernel@vger.kernel.org,
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: Re: [PATCH 1/5] fs/stat: Define DAX statx attribute
Date: Tue, 22 Oct 2019 09:51:29 -0700 [thread overview]
Message-ID: <20191022165128.GA5432@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <119b57ed-2799-c499-00df-50da80d23612@plexistor.com>
On Tue, Oct 22, 2019 at 02:32:04PM +0300, Boaz Harrosh wrote:
> On 20/10/2019 18:59, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> >
> > In order for users to determine if a file is currently operating in DAX
> > mode (effective DAX). Define a statx attribute value and set that
> > attribute if the effective DAX flag is set.
> >
> > To go along with this we propose the following addition to the statx man
> > page:
> >
> > STATX_ATTR_DAX
> >
> > DAX (cpu direct access) is a file mode that attempts to minimize
> > software cache effects for both I/O and memory mappings of this
> > file. It requires a capable device, a compatible filesystem
> > block size, and filesystem opt-in. It generally assumes all
> > accesses are via cpu load / store instructions which can
> > minimize overhead for small accesses, but adversely affect cpu
> > utilization for large transfers. File I/O is done directly
> > to/from user-space buffers. While the DAX property tends to
> > result in data being transferred synchronously it does not give
> > the guarantees of synchronous I/O that data and necessary
> > metadata are transferred. Memory mapped I/O may be performed
> > with direct mappings that bypass system memory buffering. Again
> > while memory-mapped I/O tends to result in data being
> > transferred synchronously it does not guarantee synchronous
> > metadata updates. A dax file may optionally support being mapped
> > with the MAP_SYNC flag which does allow cpu store operations to
> > be considered synchronous modulo cpu cache effects.
> >
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > ---
> > fs/stat.c | 3 +++
> > include/uapi/linux/stat.h | 1 +
> > 2 files changed, 4 insertions(+)
> >
> > diff --git a/fs/stat.c b/fs/stat.c
> > index c38e4c2e1221..59ca360c1ffb 100644
> > --- a/fs/stat.c
> > +++ b/fs/stat.c
> > @@ -77,6 +77,9 @@ int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
> > if (IS_AUTOMOUNT(inode))
> > stat->attributes |= STATX_ATTR_AUTOMOUNT;
> >
> > + if (inode->i_flags & S_DAX)
>
> Is there a reason not to use IS_DAX(inode) ?
No, just forgot there was a macro when this was written. Changed.
Thanks,
Ira
>
> > + stat->attributes |= STATX_ATTR_DAX;
> > +
> > if (inode->i_op->getattr)
> > return inode->i_op->getattr(path, stat, request_mask,
> > query_flags);
> > diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
> > index 7b35e98d3c58..5b0962121ef7 100644
> > --- a/include/uapi/linux/stat.h
> > +++ b/include/uapi/linux/stat.h
> > @@ -169,6 +169,7 @@ struct statx {
> > #define STATX_ATTR_ENCRYPTED 0x00000800 /* [I] File requires key to decrypt in fs */
> >
> > #define STATX_ATTR_AUTOMOUNT 0x00001000 /* Dir: Automount trigger */
> > +#define STATX_ATTR_DAX 0x00002000 /* [I] File is DAX */
> >
> >
> > #endif /* _UAPI_LINUX_STAT_H */
> >
>
next prev parent reply other threads:[~2019-10-22 16:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-20 15:59 [PATCH 0/5] Enable per-file/directory DAX operations ira.weiny
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191022165128.GA5432@iweiny-DESK2.sc.intel.com \
--to=ira.weiny@intel.com \
--cc=boaz@plexistor.com \
--cc=dan.j.williams@intel.com \
--cc=darrick.wong@oracle.com \
--cc=david@fromorbit.com \
--cc=hch@lst.de \
--cc=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).