[PATCH] Update documentation of cgroups tasks and procs files

[Li Zefan]

Paul Menage wrote:
> Update documentation of cgroups tasks and procs files
> 
> Document the cgroup.procs file.
> 
> Clarify the semantics of the cgroup.procs and tasks files.  Although
> the current cgroup.procs interface returns a sorted and uniqified list
> of pids, potential future performance enhancements could result in
> those properties being removed - explicitly document this aspect of
> the API.
> 
> There are no existing users of cgroup.procs, so compatibility isn't an
> issue.  There are users of the "tasks" file, but none that would
> appear to break in the event of the sorted property being broken. The
> standard "libcpuset" explicitly sorts the results of reading from the
> tasks file, and "libcg" and other users don't appear to care about
> ordering.
> 
> Signed-off-by: Paul Menage <menage at google.com>
> 

Reviewed-by: Li Zefan <lizf at cn.fujitsu.com>