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

[Robert Foss]

On 2016-08-14 05:04 AM, Michal Hocko wrote:
> On Fri 12-08-16 18:04:19, robert.foss@xxxxxxxxxxxxx wrote:
> > From: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> >
> > 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