[PATCH] proc.5: Add info about /proc/[pid]/map_files directory

[PATCH] proc.5: Add info about /proc/[pid]/map_files directory

[Pavel Emelyanov]

It was added into Linux v3.3 and provides info about files being mmap-ed in
a way _very_ similar to how /proc/[pid]/fd works. Thus I thought that the
best place for the map_files' doc is where where the fd's doc is.

Signed-off-by: Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>

---

diff --git a/man5/proc.5 b/man5/proc.5
index 30ca3a9..1226747 100644
--- a/man5/proc.5
+++ b/man5/proc.5
@@ -285,6 +285,23 @@ Thus the example command above could be written as:
 .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..."
 .fi
 .in
+.TP
+.IR /proc/[pid]/map_files/ " (since kernel 3.3)
+This subdirectory contains entries corresponding to memory mapped
+files (see
+.BR mmap (2)).
+Entries are named by memory region start and end pair,
+and are symbolic links to the corresponding files.
+
+Although these entries are present for memory regions that were
+mapped with 
+.BR MAP_FILE
+flag, the way anonymous shared memory (regions created with
+.B MAP_ANON | MAP_SHARED
+flags)
+is implemented in Linux
+makes such regions also appear on this directory. In that case
+the target file would be the /dev/zero one.
 .\" FIXME Describe /proc/[pid]/loginuid
 .\"       Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
 .\"       CONFIG_AUDITSYSCALL
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Re: [PATCH] proc.5: Add info about /proc/[pid]/map_files directory

[Michael Kerrisk (man-pages)]

Hi Pavel,

On Mon, Feb 18, 2013 at 5:50 PM, Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org> wrote:
> It was added into Linux v3.3 and provides info about files being mmap-ed in
> a way _very_ similar to how /proc/[pid]/fd works. Thus I thought that the
> best place for the map_files' doc is where where the fd's doc is.
>
> Signed-off-by: Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>

Could you please resubmit with some added text that shows an example
of what you see in this file (including a /dev/zero case)? Also, the
patch should mention that CONFIG_CHECKPOINT_RESTORE is required.

Thanks,

Michael

> ---
>
> diff --git a/man5/proc.5 b/man5/proc.5
> index 30ca3a9..1226747 100644
> --- a/man5/proc.5
> +++ b/man5/proc.5
> @@ -285,6 +285,23 @@ Thus the example command above could be written as:
>  .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..."
>  .fi
>  .in
> +.TP
> +.IR /proc/[pid]/map_files/ " (since kernel 3.3)
> +This subdirectory contains entries corresponding to memory mapped
> +files (see
> +.BR mmap (2)).
> +Entries are named by memory region start and end pair,
> +and are symbolic links to the corresponding files.
> +
> +Although these entries are present for memory regions that were
> +mapped with
> +.BR MAP_FILE
> +flag, the way anonymous shared memory (regions created with
> +.B MAP_ANON | MAP_SHARED
> +flags)
> +is implemented in Linux
> +makes such regions also appear on this directory. In that case
> +the target file would be the /dev/zero one.
>  .\" FIXME Describe /proc/[pid]/loginuid
>  .\"       Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
>  .\"       CONFIG_AUDITSYSCALL



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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Re: [PATCH] proc.5: Add info about /proc/[pid]/map_files directory

[Michael Kerrisk (man-pages)]

Hi Pavel... Ping!

Cheers,

Michael

On Thu, Feb 28, 2013 at 3:20 PM, Michael Kerrisk (man-pages)
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Hi Pavel,
>
> On Mon, Feb 18, 2013 at 5:50 PM, Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org> wrote:
>> It was added into Linux v3.3 and provides info about files being mmap-ed in
>> a way _very_ similar to how /proc/[pid]/fd works. Thus I thought that the
>> best place for the map_files' doc is where where the fd's doc is.
>>
>> Signed-off-by: Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
>
> Could you please resubmit with some added text that shows an example
> of what you see in this file (including a /dev/zero case)? Also, the
> patch should mention that CONFIG_CHECKPOINT_RESTORE is required.
>
> Thanks,
>
> Michael
>
>> ---
>>
>> diff --git a/man5/proc.5 b/man5/proc.5
>> index 30ca3a9..1226747 100644
>> --- a/man5/proc.5
>> +++ b/man5/proc.5
>> @@ -285,6 +285,23 @@ Thus the example command above could be written as:
>>  .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..."
>>  .fi
>>  .in
>> +.TP
>> +.IR /proc/[pid]/map_files/ " (since kernel 3.3)
>> +This subdirectory contains entries corresponding to memory mapped
>> +files (see
>> +.BR mmap (2)).
>> +Entries are named by memory region start and end pair,
>> +and are symbolic links to the corresponding files.
>> +
>> +Although these entries are present for memory regions that were
>> +mapped with
>> +.BR MAP_FILE
>> +flag, the way anonymous shared memory (regions created with
>> +.B MAP_ANON | MAP_SHARED
>> +flags)
>> +is implemented in Linux
>> +makes such regions also appear on this directory. In that case
>> +the target file would be the /dev/zero one.
>>  .\" FIXME Describe /proc/[pid]/loginuid
>>  .\"       Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
>>  .\"       CONFIG_AUDITSYSCALL
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Author of "The Linux Programming Interface"; http://man7.org/tlpi/



--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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Re: [PATCH] proc.5: Add info about /proc/[pid]/map_files directory

[Pavel Emelyanov]

On 04/16/2013 10:02 AM, Michael Kerrisk (man-pages) wrote:
> Hi Pavel... Ping!

Sorry, Michael...
This patch is in my man git tree for several weeks already,
I will re-send one soon.

> Cheers,
> 
> Michael
> 
> On Thu, Feb 28, 2013 at 3:20 PM, Michael Kerrisk (man-pages)
> <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Hi Pavel,
>>
>> On Mon, Feb 18, 2013 at 5:50 PM, Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org> wrote:
>>> It was added into Linux v3.3 and provides info about files being mmap-ed in
>>> a way _very_ similar to how /proc/[pid]/fd works. Thus I thought that the
>>> best place for the map_files' doc is where where the fd's doc is.
>>>
>>> Signed-off-by: Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
>>
>> Could you please resubmit with some added text that shows an example
>> of what you see in this file (including a /dev/zero case)? Also, the
>> patch should mention that CONFIG_CHECKPOINT_RESTORE is required.
>>
>> Thanks,
>>
>> Michael
>>
>>> ---
>>>
>>> diff --git a/man5/proc.5 b/man5/proc.5
>>> index 30ca3a9..1226747 100644
>>> --- a/man5/proc.5
>>> +++ b/man5/proc.5
>>> @@ -285,6 +285,23 @@ Thus the example command above could be written as:
>>>  .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..."
>>>  .fi
>>>  .in
>>> +.TP
>>> +.IR /proc/[pid]/map_files/ " (since kernel 3.3)
>>> +This subdirectory contains entries corresponding to memory mapped
>>> +files (see
>>> +.BR mmap (2)).
>>> +Entries are named by memory region start and end pair,
>>> +and are symbolic links to the corresponding files.
>>> +
>>> +Although these entries are present for memory regions that were
>>> +mapped with
>>> +.BR MAP_FILE
>>> +flag, the way anonymous shared memory (regions created with
>>> +.B MAP_ANON | MAP_SHARED
>>> +flags)
>>> +is implemented in Linux
>>> +makes such regions also appear on this directory. In that case
>>> +the target file would be the /dev/zero one.
>>>  .\" FIXME Describe /proc/[pid]/loginuid
>>>  .\"       Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
>>>  .\"       CONFIG_AUDITSYSCALL
>>
>>
>>
>> --
>> Michael Kerrisk
>> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
>> Author of "The Linux Programming Interface"; http://man7.org/tlpi/
> 
> 
> 
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Author of "The Linux Programming Interface"; http://man7.org/tlpi/
> .
> 


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