From: Johannes Thumshirn <jthumshirn@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-nvdimm@lists.01.org
Subject: Re: Problems with VM_MIXEDMAP removal from /proc/<pid>/smaps
Date: Tue, 2 Oct 2018 14:10:39 +0200 [thread overview]
Message-ID: <20181002121039.GA3274@linux-x5ow.site> (raw)
In-Reply-To: <20181002100531.GC4135@quack2.suse.cz>
On Tue, Oct 02, 2018 at 12:05:31PM +0200, Jan Kara wrote:
> Hello,
>
> commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has
> removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the
> mean time certain customer of ours started poking into /proc/<pid>/smaps
> and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA
> flags, the application just fails to start complaining that DAX support is
> missing in the kernel. The question now is how do we go about this?
OK naive question from me, how do we want an application to be able to
check if it is running on a DAX mapping?
AFAIU DAX is always associated with a file descriptor of some kind (be
it a real file with filesystem dax or the /dev/dax device file for
device dax). So could a new fcntl() be of any help here? IS_DAX() only
checks for the S_DAX flag in inode::i_flags, so this should be doable
for both fsdax and devdax.
I haven't tried it yet but it should be fairly easy to come up with
something like this.
Byte,
Johannes
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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WARNING: multiple messages have this Message-ID (diff)
From: Johannes Thumshirn <jthumshirn@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
linux-nvdimm@lists.01.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: Problems with VM_MIXEDMAP removal from /proc/<pid>/smaps
Date: Tue, 2 Oct 2018 14:10:39 +0200 [thread overview]
Message-ID: <20181002121039.GA3274@linux-x5ow.site> (raw)
In-Reply-To: <20181002100531.GC4135@quack2.suse.cz>
On Tue, Oct 02, 2018 at 12:05:31PM +0200, Jan Kara wrote:
> Hello,
>
> commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has
> removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the
> mean time certain customer of ours started poking into /proc/<pid>/smaps
> and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA
> flags, the application just fails to start complaining that DAX support is
> missing in the kernel. The question now is how do we go about this?
OK naive question from me, how do we want an application to be able to
check if it is running on a DAX mapping?
AFAIU DAX is always associated with a file descriptor of some kind (be
it a real file with filesystem dax or the /dev/dax device file for
device dax). So could a new fcntl() be of any help here? IS_DAX() only
checks for the S_DAX flag in inode::i_flags, so this should be doable
for both fsdax and devdax.
I haven't tried it yet but it should be fairly easy to come up with
something like this.
Byte,
Johannes
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
GF: Felix Imend�rffer, Jane Smithard, Graham Norton
HRB 21284 (AG N�rnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Thumshirn <jthumshirn@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
linux-nvdimm@lists.01.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: Problems with VM_MIXEDMAP removal from /proc/<pid>/smaps
Date: Tue, 2 Oct 2018 14:10:39 +0200 [thread overview]
Message-ID: <20181002121039.GA3274@linux-x5ow.site> (raw)
In-Reply-To: <20181002100531.GC4135@quack2.suse.cz>
On Tue, Oct 02, 2018 at 12:05:31PM +0200, Jan Kara wrote:
> Hello,
>
> commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has
> removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the
> mean time certain customer of ours started poking into /proc/<pid>/smaps
> and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA
> flags, the application just fails to start complaining that DAX support is
> missing in the kernel. The question now is how do we go about this?
OK naive question from me, how do we want an application to be able to
check if it is running on a DAX mapping?
AFAIU DAX is always associated with a file descriptor of some kind (be
it a real file with filesystem dax or the /dev/dax device file for
device dax). So could a new fcntl() be of any help here? IS_DAX() only
checks for the S_DAX flag in inode::i_flags, so this should be doable
for both fsdax and devdax.
I haven't tried it yet but it should be fairly easy to come up with
something like this.
Byte,
Johannes
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nurnberg
GF: Felix Imendorffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nurnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
next prev parent reply other threads:[~2018-10-02 12:10 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 10:05 Problems with VM_MIXEDMAP removal from /proc/<pid>/smaps Jan Kara
2018-10-02 10:05 ` Jan Kara
2018-10-02 10:05 ` Jan Kara
2018-10-02 10:50 ` Michal Hocko
2018-10-02 10:50 ` Michal Hocko
2018-10-02 13:32 ` Jan Kara
2018-10-02 13:32 ` Jan Kara
2018-10-02 12:10 ` Johannes Thumshirn [this message]
2018-10-02 12:10 ` Johannes Thumshirn
2018-10-02 12:10 ` Johannes Thumshirn
2018-10-02 14:20 ` Johannes Thumshirn
2018-10-02 14:20 ` Johannes Thumshirn
2018-10-02 14:20 ` Johannes Thumshirn
2018-10-02 14:45 ` Christoph Hellwig
2018-10-02 14:45 ` Christoph Hellwig
2018-10-02 15:01 ` Johannes Thumshirn
2018-10-02 15:01 ` Johannes Thumshirn
2018-10-02 15:01 ` Johannes Thumshirn
2018-10-02 15:06 ` Christoph Hellwig
2018-10-02 15:06 ` Christoph Hellwig
2018-10-04 10:09 ` Johannes Thumshirn
2018-10-04 10:09 ` Johannes Thumshirn
2018-10-04 10:09 ` Johannes Thumshirn
2018-10-05 6:25 ` Christoph Hellwig
2018-10-05 6:25 ` Christoph Hellwig
2018-10-05 6:35 ` Johannes Thumshirn
2018-10-05 6:35 ` Johannes Thumshirn
2018-10-05 6:35 ` Johannes Thumshirn
2018-10-06 1:17 ` Dan Williams
2018-10-06 1:17 ` Dan Williams
2018-10-14 15:47 ` Dan Williams
2018-10-14 15:47 ` Dan Williams
2018-10-17 20:01 ` Dan Williams
2018-10-18 17:43 ` Jan Kara
2018-10-18 17:43 ` Jan Kara
2018-10-18 19:10 ` Dan Williams
2018-10-18 19:10 ` Dan Williams
2018-10-19 3:01 ` Dave Chinner
2018-10-19 3:01 ` Dave Chinner
2018-10-02 14:29 ` Jan Kara
2018-10-02 14:29 ` Jan Kara
2018-10-02 14:29 ` Jan Kara
2018-10-02 14:37 ` Christoph Hellwig
2018-10-02 14:37 ` Christoph Hellwig
2018-10-02 14:37 ` Christoph Hellwig
2018-10-02 14:44 ` Johannes Thumshirn
2018-10-02 14:44 ` Johannes Thumshirn
2018-10-02 14:44 ` Johannes Thumshirn
2018-10-02 14:44 ` Johannes Thumshirn
2018-10-02 14:44 ` Johannes Thumshirn
2018-10-02 14:52 ` Christoph Hellwig
2018-10-02 14:52 ` Christoph Hellwig
2018-10-02 14:52 ` Christoph Hellwig
2018-10-02 15:31 ` Jan Kara
2018-10-02 15:31 ` Jan Kara
2018-10-02 15:31 ` Jan Kara
2018-10-02 20:18 ` Dan Williams
2018-10-02 20:18 ` Dan Williams
2018-10-03 12:50 ` Jan Kara
2018-10-03 12:50 ` Jan Kara
2018-10-03 12:50 ` Jan Kara
2018-10-03 14:38 ` Dan Williams
2018-10-03 14:38 ` Dan Williams
2018-10-03 15:06 ` Jan Kara
2018-10-03 15:06 ` Jan Kara
2018-10-03 15:06 ` Jan Kara
2018-10-03 15:13 ` Dan Williams
2018-10-03 15:13 ` Dan Williams
2018-10-03 15:13 ` Dan Williams
2018-10-03 16:44 ` Jan Kara
2018-10-03 16:44 ` Jan Kara
2018-10-03 16:44 ` Jan Kara
2018-10-03 21:13 ` Dan Williams
2018-10-03 21:13 ` Dan Williams
2018-10-03 21:13 ` Dan Williams
2018-10-04 10:04 ` Johannes Thumshirn
2018-10-04 10:04 ` Johannes Thumshirn
2018-10-04 10:04 ` Johannes Thumshirn
2018-10-04 10:04 ` Johannes Thumshirn
2018-10-04 10:04 ` Johannes Thumshirn
2018-10-02 15:07 ` Jan Kara
2018-10-02 15:07 ` Jan Kara
2018-10-02 15:07 ` Jan Kara
2018-10-17 20:23 ` Jeff Moyer
2018-10-17 20:23 ` Jeff Moyer
2018-10-17 20:23 ` Jeff Moyer
2018-10-17 20:23 ` Jeff Moyer
2018-10-18 0:25 ` Dave Chinner
2018-10-18 0:25 ` Dave Chinner
2018-10-18 0:25 ` Dave Chinner
2018-10-18 14:55 ` Jan Kara
2018-10-18 14:55 ` Jan Kara
2018-10-19 0:43 ` Dave Chinner
2018-10-19 0:43 ` Dave Chinner
2018-10-19 0:43 ` Dave Chinner
2018-10-30 6:30 ` Dan Williams
2018-10-30 6:30 ` Dan Williams
2018-10-30 6:30 ` Dan Williams
2018-10-30 22:49 ` Dave Chinner
2018-10-30 22:49 ` Dave Chinner
2018-10-30 22:49 ` Dave Chinner
2018-10-30 22:59 ` Dan Williams
2018-10-30 22:59 ` Dan Williams
2018-10-30 22:59 ` Dan Williams
2018-10-31 5:59 ` y-goto
2018-10-31 5:59 ` y-goto-LMvhtfratI1BDgjK7y7TUQ
2018-10-31 5:59 ` y-goto
2018-11-01 23:00 ` Dave Chinner
2018-11-01 23:00 ` Dave Chinner
2018-11-01 23:00 ` Dave Chinner
2018-11-02 1:43 ` y-goto
2018-11-02 1:43 ` y-goto-LMvhtfratI1BDgjK7y7TUQ
2018-11-02 1:43 ` y-goto
2018-10-18 21:05 ` Jeff Moyer
2018-10-18 21:05 ` Jeff Moyer
2018-10-18 21:05 ` Jeff Moyer
2018-10-18 21:05 ` Jeff Moyer
2018-10-09 19:43 ` Jeff Moyer
2018-10-09 19:43 ` Jeff Moyer
2018-10-09 19:43 ` Jeff Moyer
2018-10-16 8:25 ` Jan Kara
2018-10-16 8:25 ` Jan Kara
2018-10-16 12:35 ` Jeff Moyer
2018-10-16 12:35 ` Jeff Moyer
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