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From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-xfs@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-api@vger.kernel.org, Christoph Hellwig <hch@infradead.org>,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-ext4@vger.kernel.org
Subject: Re: [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC
Date: Tue, 24 Oct 2017 15:10:07 -0600	[thread overview]
Message-ID: <20171024211007.GA1611@linux.intel.com> (raw)
In-Reply-To: <20171024152415.22864-19-jack@suse.cz>

On Tue, Oct 24, 2017 at 05:24:15PM +0200, Jan Kara wrote:
> Signed-off-by: Jan Kara <jack@suse.cz>

This looks unchanged since the previous version?

> ---
>  man2/mmap.2 | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/man2/mmap.2 b/man2/mmap.2
> index 47c3148653be..598ff0c64f7f 100644
> --- a/man2/mmap.2
> +++ b/man2/mmap.2
> @@ -125,6 +125,21 @@ are carried through to the underlying file.
>  to the underlying file requires the use of
>  .BR msync (2).)
>  .TP
> +.B MAP_SHARED_VALIDATE
> +The same as
> +.B MAP_SHARED
> +except that
> +.B MAP_SHARED
> +mappings ignore unknown flags in
> +.IR flags .
> +In contrast when creating mapping of
> +.B MAP_SHARED_VALIDATE
> +mapping type, the kernel verifies all passed flags are known and fails the
> +mapping with
> +.BR EOPNOTSUPP
> +otherwise. This mapping type is also required to be able to use some mapping
> +flags.
> +.TP
>  .B MAP_PRIVATE
>  Create a private copy-on-write mapping.
>  Updates to the mapping are not visible to other processes
> @@ -352,6 +367,21 @@ option.
>  Because of the security implications,
>  that option is normally enabled only on embedded devices
>  (i.e., devices where one has complete control of the contents of user memory).
> +.TP
> +.BR MAP_SYNC " (since Linux 4.15)"
> +This flags is available only with
> +.B MAP_SHARED_VALIDATE
> +mapping type. Mappings of
> +.B MAP_SHARED
> +type will silently ignore this flag.
> +This flag is supported only for files supporting DAX (direct mapping of persistent
> +memory). For other files, creating mapping with this flag results in
> +.B EOPNOTSUPP
> +error. Shared file mappings with this flag provide the guarantee that while
> +some memory is writeably mapped in the address space of the process, it will
> +be visible in the same file at the same offset even after the system crashes or
> +is rebooted. This allows users of such mappings to make data modifications
> +persistent in a more efficient way using appropriate CPU instructions.
>  .PP
>  Of the above flags, only
>  .B MAP_FIXED
> -- 
> 2.12.3
> 
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-ext4@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-api@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC
Date: Tue, 24 Oct 2017 15:10:07 -0600	[thread overview]
Message-ID: <20171024211007.GA1611@linux.intel.com> (raw)
In-Reply-To: <20171024152415.22864-19-jack@suse.cz>

On Tue, Oct 24, 2017 at 05:24:15PM +0200, Jan Kara wrote:
> Signed-off-by: Jan Kara <jack@suse.cz>

This looks unchanged since the previous version?

> ---
>  man2/mmap.2 | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/man2/mmap.2 b/man2/mmap.2
> index 47c3148653be..598ff0c64f7f 100644
> --- a/man2/mmap.2
> +++ b/man2/mmap.2
> @@ -125,6 +125,21 @@ are carried through to the underlying file.
>  to the underlying file requires the use of
>  .BR msync (2).)
>  .TP
> +.B MAP_SHARED_VALIDATE
> +The same as
> +.B MAP_SHARED
> +except that
> +.B MAP_SHARED
> +mappings ignore unknown flags in
> +.IR flags .
> +In contrast when creating mapping of
> +.B MAP_SHARED_VALIDATE
> +mapping type, the kernel verifies all passed flags are known and fails the
> +mapping with
> +.BR EOPNOTSUPP
> +otherwise. This mapping type is also required to be able to use some mapping
> +flags.
> +.TP
>  .B MAP_PRIVATE
>  Create a private copy-on-write mapping.
>  Updates to the mapping are not visible to other processes
> @@ -352,6 +367,21 @@ option.
>  Because of the security implications,
>  that option is normally enabled only on embedded devices
>  (i.e., devices where one has complete control of the contents of user memory).
> +.TP
> +.BR MAP_SYNC " (since Linux 4.15)"
> +This flags is available only with
> +.B MAP_SHARED_VALIDATE
> +mapping type. Mappings of
> +.B MAP_SHARED
> +type will silently ignore this flag.
> +This flag is supported only for files supporting DAX (direct mapping of persistent
> +memory). For other files, creating mapping with this flag results in
> +.B EOPNOTSUPP
> +error. Shared file mappings with this flag provide the guarantee that while
> +some memory is writeably mapped in the address space of the process, it will
> +be visible in the same file at the same offset even after the system crashes or
> +is rebooted. This allows users of such mappings to make data modifications
> +persistent in a more efficient way using appropriate CPU instructions.
>  .PP
>  Of the above flags, only
>  .B MAP_FIXED
> -- 
> 2.12.3
> 

--
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WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-ext4@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-api@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC
Date: Tue, 24 Oct 2017 15:10:07 -0600	[thread overview]
Message-ID: <20171024211007.GA1611@linux.intel.com> (raw)
In-Reply-To: <20171024152415.22864-19-jack@suse.cz>

On Tue, Oct 24, 2017 at 05:24:15PM +0200, Jan Kara wrote:
> Signed-off-by: Jan Kara <jack@suse.cz>

This looks unchanged since the previous version?

> ---
>  man2/mmap.2 | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/man2/mmap.2 b/man2/mmap.2
> index 47c3148653be..598ff0c64f7f 100644
> --- a/man2/mmap.2
> +++ b/man2/mmap.2
> @@ -125,6 +125,21 @@ are carried through to the underlying file.
>  to the underlying file requires the use of
>  .BR msync (2).)
>  .TP
> +.B MAP_SHARED_VALIDATE
> +The same as
> +.B MAP_SHARED
> +except that
> +.B MAP_SHARED
> +mappings ignore unknown flags in
> +.IR flags .
> +In contrast when creating mapping of
> +.B MAP_SHARED_VALIDATE
> +mapping type, the kernel verifies all passed flags are known and fails the
> +mapping with
> +.BR EOPNOTSUPP
> +otherwise. This mapping type is also required to be able to use some mapping
> +flags.
> +.TP
>  .B MAP_PRIVATE
>  Create a private copy-on-write mapping.
>  Updates to the mapping are not visible to other processes
> @@ -352,6 +367,21 @@ option.
>  Because of the security implications,
>  that option is normally enabled only on embedded devices
>  (i.e., devices where one has complete control of the contents of user memory).
> +.TP
> +.BR MAP_SYNC " (since Linux 4.15)"
> +This flags is available only with
> +.B MAP_SHARED_VALIDATE
> +mapping type. Mappings of
> +.B MAP_SHARED
> +type will silently ignore this flag.
> +This flag is supported only for files supporting DAX (direct mapping of persistent
> +memory). For other files, creating mapping with this flag results in
> +.B EOPNOTSUPP
> +error. Shared file mappings with this flag provide the guarantee that while
> +some memory is writeably mapped in the address space of the process, it will
> +be visible in the same file at the same offset even after the system crashes or
> +is rebooted. This allows users of such mappings to make data modifications
> +persistent in a more efficient way using appropriate CPU instructions.
>  .PP
>  Of the above flags, only
>  .B MAP_FIXED
> -- 
> 2.12.3
> 

  reply	other threads:[~2017-10-24 21:06 UTC|newest]

Thread overview: 173+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-24 15:23 [PATCH 0/17 v5] dax, ext4, xfs: Synchronous page faults Jan Kara
2017-10-24 15:23 ` Jan Kara
2017-10-24 15:23 ` Jan Kara
2017-10-24 15:23 ` Jan Kara
2017-10-24 15:23 ` [PATCH 01/17] mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 21:21   ` Ross Zwisler
2017-10-24 21:21     ` Ross Zwisler
2017-10-24 21:21     ` Ross Zwisler
2017-10-24 21:21     ` Ross Zwisler
2017-10-24 15:23 ` [PATCH 02/17] mm: Remove VM_FAULT_HWPOISON_LARGE_MASK Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:23   ` Jan Kara
2017-10-24 15:24 ` [PATCH 03/17] dax: Simplify arguments of dax_insert_mapping() Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 04/17] dax: Factor out getting of pfn out of iomap Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 05/17] dax: Create local variable for VMA in dax_iomap_pte_fault() Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 06/17] dax: Create local variable for vmf->flags & FAULT_FLAG_WRITE test Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 07/17] dax: Inline dax_insert_mapping() into the callsite Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 08/17] dax: Inline dax_pmd_insert_mapping() " Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 09/17] dax: Fix comment describing dax_iomap_fault() Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 10/17] dax: Allow dax_iomap_fault() to return pfn Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 11/17] dax: Allow tuning whether dax_insert_mapping_entry() dirties entry Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 12/17] mm: Define MAP_SYNC and VM_SYNC flags Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 13/17] dax, iomap: Add support for synchronous faults Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 14/17] dax: Implement dax_finish_sync_fault() Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 15/17] ext4: Simplify error handling in ext4_dax_huge_fault() Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 16/17] ext4: Support for synchronous DAX faults Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24 ` [PATCH 17/17] xfs: support " Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 21:29   ` Ross Zwisler
2017-10-24 21:29     ` Ross Zwisler
2017-10-24 21:29     ` Ross Zwisler
2017-10-24 22:23   ` Dave Chinner
2017-10-24 22:23     ` Dave Chinner
2017-10-24 22:23     ` Dave Chinner
2017-10-26 15:48     ` Jan Kara
2017-10-26 15:48       ` Jan Kara
2017-10-26 15:48       ` Jan Kara
2017-10-26 15:48       ` Jan Kara
2017-10-26 21:16       ` Dave Chinner
2017-10-26 21:16         ` Dave Chinner
2017-10-26 21:16         ` Dave Chinner
2017-10-26 21:16         ` Dave Chinner
2017-10-27 10:08         ` Jan Kara
2017-10-27 10:08           ` Jan Kara
2017-10-27 10:08           ` Jan Kara
2017-10-31 15:19           ` Jan Kara
2017-10-31 15:19             ` Jan Kara
2017-10-31 15:19             ` Jan Kara
2017-10-31 15:19             ` Jan Kara
2017-10-31 21:50             ` Dan Williams
2017-10-31 21:50               ` Dan Williams
2017-10-31 21:50               ` Dan Williams
2017-10-31 21:50               ` Dan Williams
2017-11-01  3:47               ` Ross Zwisler
2017-11-01  3:47                 ` Ross Zwisler
2017-11-01  3:47                 ` Ross Zwisler
2017-11-01  3:47                 ` Ross Zwisler
2017-10-27  6:43       ` Christoph Hellwig
2017-10-27  6:43         ` Christoph Hellwig
2017-10-27  9:13         ` Jan Kara
2017-10-27  9:13           ` Jan Kara
2017-10-27  9:13           ` Jan Kara
2017-10-27  9:13           ` Jan Kara
2017-10-24 15:24 ` [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 15:24   ` Jan Kara
2017-10-24 21:10   ` Ross Zwisler [this message]
2017-10-24 21:10     ` Ross Zwisler
2017-10-24 21:10     ` Ross Zwisler
2017-10-26 13:24     ` Jan Kara
2017-10-26 13:24       ` Jan Kara
2017-10-26 13:24       ` Jan Kara
2017-10-26 18:22       ` Ross Zwisler
2017-10-26 18:22         ` Ross Zwisler
2017-10-26 18:22         ` Ross Zwisler
2017-10-26 18:22         ` Ross Zwisler
  -- strict thread matches above, loose matches on Subject: below --
2017-11-01 15:36 [PATCH 0/18 v6] dax, ext4, xfs: Synchronous page faults Jan Kara
2017-11-01 15:36 ` [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC Jan Kara
2017-11-01 15:36   ` Jan Kara
2017-11-01 15:36   ` Jan Kara
2017-11-01 15:36   ` Jan Kara
2017-11-01 15:36   ` Jan Kara
2018-04-12 13:00   ` Michael Kerrisk (man-pages)
2018-04-12 13:00     ` Michael Kerrisk (man-pages)
2018-04-12 13:00     ` Michael Kerrisk (man-pages)
2018-04-12 14:00     ` Ross Zwisler
2018-04-12 14:00       ` Ross Zwisler
2018-04-12 14:22     ` Jan Kara
2018-04-12 14:22       ` Jan Kara
2018-04-12 14:22       ` Jan Kara
2018-04-12 18:20       ` Michael Kerrisk (man-pages)
2018-04-12 18:20         ` Michael Kerrisk (man-pages)
2018-04-12 18:20         ` Michael Kerrisk (man-pages)
2018-04-13 11:17         ` Jan Kara
2018-04-13 11:17           ` Jan Kara
2018-04-13 11:17           ` Jan Kara
2017-10-19 12:57 [PATCH 0/17 v4] dax, ext4, xfs: Synchronous page faults Jan Kara
2017-10-19 12:58 ` [PATCH] mmap.2: Add description of MAP_SHARED_VALIDATE and MAP_SYNC Jan Kara
2017-10-19 12:58   ` Jan Kara
2017-10-19 12:58   ` Jan Kara
2017-10-19 12:58   ` Jan Kara
2017-10-19 12:58   ` Jan Kara
2017-10-20 21:47   ` Ross Zwisler
2017-10-20 21:47     ` Ross Zwisler
2017-10-20 21:47     ` Ross Zwisler
2017-10-24 13:27     ` Jan Kara
2017-10-24 13:27       ` Jan Kara
2017-10-24 13:27       ` Jan Kara
2017-10-24 14:55       ` Ross Zwisler
2017-10-24 14:55         ` Ross Zwisler
2017-10-24 14:55         ` Ross Zwisler

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