memcg: a patch series for next [0/9]

Hi, 

This post is for showing what I'm trying now.

This patch set is for memory resource controller.
4 purposes here.
  - improve performance of memcg.
  - remove lock_page_cgroup()
  - making page_cgroup->flags to be atomic_ops.
  - support mem+swap controller.

But this is still under test and the series is not well organised.
and base tree is old. (2.6.27-rc1-mm1) I'll rebase this set to newer mmtom tree.

Maybe this set have some troubles/objections but I think the direction is not bad.

Patch description. (patch ordering is bad. I'll fix in the next post.)

[1/9] ... private_counter ...replace res_counter with my own counter.
          This is for supporting mem+swap controller.
          (And I think memcg has a bit different characteristics from other
           users of res_counter....)

[2/9] ... change-order-uncharge ...
          This patch is for making it easy to handle swap-cache.

[3/9] ... atomic_flags
          This patch changes operations for page_cgroup->flags to be atomic_ops.

[4/9] ... delayed freeing.
          delaying to free page_cgroup at uncharge.

[5/9] ... RCU freeing of page_cgroup
          free page_cgroup by RCU.

[6/9] ... lockress page cgroup.
          remove lock_page_cgroup() and use RCU semantics.

[7/9] ... add preftech
          add prefetch() macro

[8/9] ... mem+swap controller base.
          introduce mem+swap controller. A bit big patch....but have tons of TODO.
          and have troubles. (it seems it's difficult to cause OOM killer.)

[9/9] ... mem+swap controller control files.
          add mem+swap controller's control files.

I'd like to push patch [2,3,4,5,6,7] first.

Thanks,
-Kame