independently, you should make each disk have its own cgroup subsystem, which only can be defined when compiling the kernel. This is impossible because every linux box has various number of disks. So you think it may be possible to make each cgroup have lots of control files for each device as a workaround. But it isn't allowed to add/remove control files when some devices are hot-added or hot-removed. Thanks, Hirokazu Takahashi.
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Wisdom of the Ancients
