[PATCHSET v2 cgroup/for-4.6] cgroup: make control mask updates modular and recursive

[Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

Hello,

Changes from v1[1] are

* Patches 0012-0014 and 0016 added.  They further refactor the
  operations and convert existing css management paths to use the new
  modular operations.

* 0005 updated to yield the correct result on v1 hierarchies too.

* 0015 updated to reflect earlier changes.

Currently, subsystem enabling and disabling in the default hierarchy
are implemented as a long chain of interdependent operations in
cgroup_subtree_control_write().  The function calculates what need to
be done to its children and excute the necessary operations.  The
function unfortunately ends up being a rather opaque blob of
operations which is difficult to wrap one's head around or reuse.

This patchset restructures control mask update so that it's composed
of discrete idempotent and recursive operations and convert existing
css managment paths to use them which makes them simpler, more robust
and capable of recursive operations.

This patchset includes the following 12 patches.

 0001-cgroup-separate-out-interface-file-creation-from-css.patch
 0002-cgroup-explicitly-track-whether-a-cgroup_subsys_stat.patch
 0003-cgroup-reorder-operations-in-cgroup_mkdir.patch
 0004-cgroup-factor-out-cgroup_create-out-of-cgroup_mkdir.patch
 0005-cgroup-introduce-cgroup_control-and-cgroup_ss_mask.patch
 0006-cgroup-factor-out-cgroup_drain_offline-from-cgroup_s.patch
 0007-cgroup-factor-out-cgroup_apply_control_disable-from-.patch
 0008-cgroup-factor-out-cgroup_apply_control_enable-from-c.patch
 0009-cgroup-make-cgroup_drain_offline-and-cgroup_apply_co.patch
 0010-cgroup-introduce-cgroup_-save-propagate-restore-_con.patch
 0011-cgroup-factor-out-cgroup_-apply-finalize-_control-fr.patch
 0012-cgroup-combine-cgroup_mutex-locking-and-offline-css-.patch
 0013-cgroup-use-cgroup_apply_enable_control-in-cgroup-cre.patch
 0014-cgroup-reimplement-rebind_subsystems-using-cgroup_ap.patch
 0015-cgroup-make-cgroup_calc_subtree_ss_mask-take-this_ss.patch
 0016-cgroup-allocate-2x-cgrp_cset_links-when-setting-up-a.patch

The patchset is available in the following git branch.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-recursive-control

diffstat follows.  Thanks.

 include/linux/cgroup-defs.h |    3 
 kernel/cgroup.c             |  760 +++++++++++++++++++++++++-------------------
 2 files changed, 446 insertions(+), 317 deletions(-)

--
tejun

[1] http://lkml.kernel.org/g/1456199146-14765-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org