[PATCH v4 0/4] per cgroup cpu statistics

[Glauber Costa <glommer@parallels.com>]

Hello,

This is the 4th version of this per-cgroup statistics. My aim with that is
to provide userspace with the necessary tools to export a view of /proc/stat
inside a container, so tools like top would work. 

I believe this version merges all the comments from Peter and Paul. Let me know
if I forgot any of them.

I now reuse put_prev_task to account for nr_switches, so no extra walks are added.
For that, I had to add another parameter to the function, but I hope this is
acceptable. Please note that this parameter would still be needed even if
Peter's patch that merges put_prev_task behavior inside pick_next_task.

This is because the previous class may live in a different class and we may
have to call it anyway. In which case a hint like this would be needed.
I believe this to be orthogonal to the work you are doing.

Peter: the patch that adds exec_clock to rt was removed. That was my bad, it
was intended to be part of the series that unifies cpu and cpuacct for the
comounted case. I have them together in my tree, and I made the cut in the wrong
place. It is not needed here.

Let me know what you think of this.

v4:
* read_seq_string used instead of read_map. This is because the
  buffer can get very big, and that's easier to fix by using seq_string
* idle time no longer exported. It can be derived from userspace easily
* "steal" changed to "wait", since steal is more our interpretation of it
* nr_switches now being accounted as we walk the tree in put_prev_task, so no
  new hierarchy walks are being inserted.
v3:
* completely reworked nr_switches gathering
* separated per-se sleep_start to be more clear about it


Glauber Costa (4):
  account guest time per-cgroup as well.
  expose fine-grained per-cpu data for cpuacct stats
  mark whenever put_prev_task is called from context_switch
  expose per-taskgroup schedstats in cgroup

 include/linux/sched.h    |    2 +-
 kernel/sched/core.c      |  178 +++++++++++++++++++++++++++++++++++++++++++---
 kernel/sched/fair.c      |   28 +++++++-
 kernel/sched/idle_task.c |    2 +-
 kernel/sched/rt.c        |    6 +-
 kernel/sched/sched.h     |    5 ++
 kernel/sched/stop_task.c |    2 +-
 7 files changed, 207 insertions(+), 16 deletions(-)

-- 
1.7.10.2