[PATCH -mm 0/3] cgroup: block device i/o bandwidth controller (v6)

[Andrea Righi]

The objective of the i/o bandwidth controller is to improve i/o performance
predictability of different cgroups sharing the same block devices.

Respect to other priority/weight-based solutions the approach used by this
controller is to explicitly choke applications' requests that directly (or
indirectly) generate i/o activity in the system.

The direct bandwidth limiting method has the advantage of improving the
performance predictability at the cost of reducing, in general, the overall
performance of the system (in terms of throughput).

Detailed informations about design, its goal and usage are described in the
documentation.

Tested against 2.6.26-rc8-mm1.

The all-in-one patch (and previous versions) can be found at:
http://download.systemimager.org/~arighi/linux/patches/io-throttle/

Changelog: (v5 -> v6)
  - do not make kernel threads to sleep
  - do not throttle i/o for pages that need to be urgently reclaimed in
    submit_bio(READ, ...) (i.e. tasks such as pdflush and kswapd when
    performing writeout)
  - minor fixes and improvements (thanks to Li Zefan review)
  - fixed a small typo in the documentation (reported by Marco Innocenti)

TODO:
  - see documentation

-Andrea