Re: [PACTH v2 0/3] Implement /proc/<pid>/totmaps

[Robert Foss <robert.foss@collabora.com>]

On 2016-08-14 05:04 AM, Michal Hocko wrote:
> On Fri 12-08-16 18:04:19, robert.foss@collabora.com wrote:
>> From: Robert Foss <robert.foss@collabora.com>
>>
>> This series implements /proc/PID/totmaps, a tool for retrieving summarized
>> information about the mappings of a process.
>
> The changelog is absolutely missing the usecase. Why do we need this?
> Why existing interfaces are not sufficient?

You are absolutely right, more info information is in 1/3.
But the gist of it is that it provides a faster and more convenient way 
of accessing the information in /proc/PID/smaps.

>
>> Changes since v1:
>> - Removed IS_ERR check from get_task_mm() function
>> - Changed comment format
>> - Moved proc_totmaps_operations declaration inside internal.h
>> - Switched to using do_maps_open() in totmaps_open() function,
>>   which provides privilege checking
>> - Error handling reworked for totmaps_open() function
>> - Switched to stack allocated struct mem_size_stats mss_sum in
>>   totmaps_proc_show() function
>> - Removed get_task_mm() in totmaps_proc_show() since priv->mm
>>   already is available
>> - Added support to proc_map_release() fork priv==NULL, to allow
>>   function to be used for all failure cases
>> - Added proc_totmaps_op and for it helper functions
>> - Added documention in separate patch
>> - Removed totmaps_release() since it was just a wrapper for
>>   proc_map_release()
>>
>>
>> Robert Foss (3):
>>   mm, proc: Implement /proc/<pid>/totmaps
>>   Documentation/filesystems: Fixed typo
>>   Documentation/filesystems: Added /proc/PID/totmaps documentation
>>
>>  Documentation/filesystems/proc.txt |  23 ++++++-
>>  fs/proc/base.c                     |   1 +
>>  fs/proc/internal.h                 |   3 +
>>  fs/proc/task_mmu.c                 | 134 +++++++++++++++++++++++++++++++++++++
>>  4 files changed, 160 insertions(+), 1 deletion(-)
>>
>> --
>> 2.7.4
>>
>