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 <[email protected]> Cc: Kees Cook <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Signed-off-by: Andrei Vagin <[email protected]> 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
