[v5 RFC PATCH 0/7]: cpuidle/x86/POWER (REDESIGN): Cleanup idlepower management code in x86, cleanup drivers/cpuidle/cpuidle.c andintroduce cpuidle to POWER.

From: Arun R Bharadwaj
Date: Tue Sep 22 2009 - 01:33:46 EST


Hi,

******** This is an RFC, not for inclusion **********

This patchset introduces cpuidle infrastructure to POWER, prototyping
for pSeries, and also does a major refactoring of current x86 idle
power management and a cleanup of cpuidle infrastructure.

My earlier iterations can be found at:

v4 --> http://lkml.org/lkml/2009/9/1/133
v3 --> http://lkml.org/lkml/2009/8/27/124
v2 --> http://lkml.org/lkml/2009/8/26/233
v1 --> http://lkml.org/lkml/2009/8/19/150

Major Changes in this iteration:
------------------------------------------

* Refactoring x86 idle power management code
Remove all instances of pm_idle and make cpuidle_idle_call as
_the_ idle routine in x86. So, cpuidle_idle_call will be
called from the main idle loop, cpu_idle instead of the
function pointer pm_idle. Also, pm_idle was used by apm module
and xen. Change those instances such that they register to
cpuidle instead.

* Cleanup drivers/cpuidle/cpuidle.c
Currently, the cpuidle implementation has weakness in the
framework where an exported pm_idle function pointer is
manipulated by various subsystem. The proposed framework has
a registration mechanism to cleanly add and remove new idle
routines from different subsystems.

* Implement cpuidle for pSeries
Implement the processor_idle module for pseries, which
registers idle loops to cpuidle and also cleanup
arch/powerpc/platforms/pseries/setup.c and remove the
redundant pseries_dedicated/shared_idle_sleep which is
implemented in processor_idle.c
Also, remove all instances of ppc_md.power_save, for the same
reason as that given for pm_idle.

TODO:
---------------------------------------------

* Currently, the list based approach that I'm using here is not
working in a clean way on a few x86 platforms which have multiple
sleep states, leading to kernel panics. So working on resolving
that.

* ppc_md.power_save has been replaced by cpuidle_idle_call only for
pseries. So this needs to be done for all POWER platforms so that
ppc_md.power_save is completely removed.

Patches included in this series:
---------------------------------------------

1/7 - cleanup drivers/cpuidle/cpuidle.c
2/7 - implement a list based approach to register a set of idle
routines.
3/7 - refactor x86 idle power management code and remove all instances
of pm_idle.
4/7 - enable cpuidle for POWER.
5/7 - remove dedicate/shared idle loops, which will be moved to
arch/powerpc/platforms/pseries/processor_idle.c
6/7 - add a default_idle idle loop for POWER.
7/7 - implement pSeries processor idle module.

Any comments on the design is welcome.

--arun
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