Memory cgroup hierarchy introduction (v4)

This patch follows several iterations of the memory controller hierarchy
patches. The hardwall approach by Kamezawa-San[1]. Version 1 of this patchset
at [2].

The current approach is based on [2] and has the following properties

1. Hierarchies are very natural in a filesystem like the cgroup filesystem.
   A multi-tree hierarchy has been supported for a long time in filesystems.
   When the feature is turned on, we honor hierarchies such that the root
   accounts for resource usage of all children and limits can be set at
   any point in the hierarchy. Any memory cgroup is limited by limits
   along the hierarchy. The total usage of all children of a node cannot
   exceed the limit of the node.
2. The hierarchy feature is selectable and off by default
3. Hierarchies are expensive and the trade off is depth versus performance.
   Hierarchies can also be completely turned off.

The patches are against 2.6.28-rc2-mm1 and were tested in a KVM instance
with SMP and swap turned on.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>

v4..v3
======
Move to iteration instead of recursion in hierarchical reclaim. Thanks
go out to Kamezawa for pushing this
Port the patches to 2.6.28-rc4 (mmotm 15th November)


v3..v2
======
1. Hierarchy selection logic, now allows use_hierarchy changes only if
   parent's use_hierarchy is set to 0 and there are no children
2. last_scanned_child is protected by cgroup_lock()
3. cgroup_lock() is released before lru_add_drain_all() in
   mem_cgroup_force_empty()

v2..v1
======
1. The hierarchy is now selectable per-subtree
2. The features file has been renamed to use_hierarchy
3. Reclaim now holds cgroup lock and the reclaim does recursive walk and reclaim

Acknowledgements
----------------

Thanks for the feedback from Li Zefan, Kamezawa Hiroyuki, Paul Menage and
others.

Series
------

memcg-hierarchy-documentation.patch
resource-counters-hierarchy-support.patch
memcg-hierarchical-reclaim.patch
memcg-add-hierarchy-selector.patch

Reviews? Comments?

References

1. http://linux.derkeiler.com/Mailing-Lists/Kernel/2008-06/m...
2. http://kerneltrap.org/mailarchive/linux-kernel/2008/4/19/...

-- 
	Balbir
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/