[PATCH v3 0/2] cgroup: add pids subsystem

[Aleksa Sarai <cyphar@cyphar.com>]

This is a further updated version of the nproc v2 patchset[1] from
advice given by Tejun Heo[2]. The main changes include:

* Switching from mm/page_counter (which is a memcg implementation
  feature) to a pid-controller-specific hierarchical charge/uncharge
  counter with limits implementation using atomic_long_t (which is also
  lockless as it is based on page_counter).

* Updates to the user-space interface to allow for the setting of no
  limit to the number of pids in a cgroup (-1 == unlimited) as well as
  renaming of the files and the removal of nproc.max_limit.

* The controller was renamed to `pids`.

[1]: https://lkml.org/lkml/2015/2/26/787
[2]: https://lkml.org/lkml/2015/3/2/437

Aleksa Sarai (2):
  cgroups: allow a cgroup subsystem to reject a fork
  cgroups: add a pids subsystem

 include/linux/cgroup.h        |   9 ++
 include/linux/cgroup_subsys.h |   4 +
 init/Kconfig                  |  12 ++
 kernel/Makefile               |   1 +
 kernel/cgroup.c               |  80 +++++++++---
 kernel/cgroup_pids.c          | 281 ++++++++++++++++++++++++++++++++++++++++++
 kernel/fork.c                 |  12 +-
 7 files changed, 381 insertions(+), 18 deletions(-)
 create mode 100644 kernel/cgroup_pids.c

-- 
2.3.1