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.hal...@canonical.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Signed-off-by: Andrei Vagin <ava...@openvz.org>

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

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