Re: [PATCH 0/2 v2] userns: show current values of user namespace counters

[Andrei Vagin]

Hello Eric,

What do you think about this series? It should be useful to know current
usage for user counters.

Thanks,
Andrei

On Mon, Aug 15, 2016 at 01:10:20PM -0700, Andrei Vagin wrote:
> Recently Eric added user namespace counters.  User namespace counters is
> a feature that allows to limit the number of various kernel objects a
> user can create. These limits are set via /proc/sys/user/ sysctls on a
> per user namespace basis and are applicable to all users in that
> namespace.
> 
> User namespace counters are not in the upstream tree yet,
> you can find them in Eric's tree:
> https://git.kernel.org/cgit/linux/kernel/git/ebiederm/user-namespace.git/log/?h=for-testing
> 
> This patch adds /proc/<pid>/userns_counts files to provide current usage
> of user namespace counters.
> 
>   > cat /proc/813/userns_counts
>   user_namespaces          101000               1
>   pid_namespaces           101000               1
>   ipc_namespaces           101000               4
>   net_namespaces           101000               2
>   mnt_namespaces           101000               5
>   mnt_namespaces           100000               1
> 
> The meanings of the columns are as follows, from left to right:
> 
>   Name         Object name
>   UID          User ID
>   Usage        Current usage
> 
> The full documentation is in the second patch.
> 
> v2: - describe this file in Documentation/filesystems/proc.txt
>     - move and rename into /proc/<pid>/userns_counts
> 
> Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx>
> 
> Andrei Vagin (1):
>   kernel: show current values of user namespace counters
> 
> Kirill Kolyshkin (1):
>   Documentation: describe /proc/<pid>/userns_counts
> 
>  Documentation/filesystems/proc.txt |  30 +++++++++++
>  fs/proc/array.c                    |  55 ++++++++++++++++++++
>  fs/proc/base.c                     |   1 +
>  fs/proc/internal.h                 |   1 +
>  include/linux/user_namespace.h     |   8 +++
>  kernel/ucount.c                    | 102 +++++++++++++++++++++++++++++++++++++
>  6 files changed, 197 insertions(+)
> 
> -- 
> 2.5.5