Messages in this thread | | | Date | Tue, 16 Dec 2008 03:30:55 -0800 | From | menage@google ... | Subject | [PATCH 0/3] CGroups: Hierarchy locking/refcount changes |
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These patches introduce new locking/refcount support for cgroups to reduce the need for subsystems to call cgroup_lock(). This will ultimately allow the atomicity of cgroup_rmdir() (which was removed recently) to be restored.
These three patches give:
1/3 - introduce a per-subsystem hierarchy_mutex which a subsystem can use to prevent changes to its own cgroup tree
2/3 - use hierarchy_mutex in place of calling cgroup_lock() in the memory controller
3/3 - introduce a css_tryget() function similar to the one recently proposed by Kamezawa, but avoiding spurious refcount failures in the event of a race between a css_tryget() and an unsuccessful cgroup_rmdir()
Future patches will likely involve:
- using hierarchy mutex in place of cgroup_lock() in more subsystems where appropriate
- restoring the atomicity of cgroup_rmdir() with respect to cgroup_create()
Signed-off-by: Paul Menage <menage@google.com>
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