[PATCH V4 0/2] Implement per policy instance of governor

[Viresh Kumar <viresh.kumar@linaro.org>]

Hi Guys,

All patches are pushed here for others to apply (you can apply from mail to):
http://git.linaro.org/gitweb?p=people/vireshk/linux.git;a=shortlog;h=refs/heads/governor-per-policy-v4

Currently, there can't be multiple instances of single governor_type. If we have
a multi-package system, where we have multiple instances of struct policy (per
package), we can't have multiple instances of same governor. i.e. We can't have
multiple instances of ondemand governor for multiple packages.

Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
governor-name/. Which again reflects that there can be only one instance of a
governor_type in the system.

This is a bottleneck for multicluster system, where we want different packages
to use same governor type, but with different tunables.

This patchset is inclined towards fixing this issue. Now we will create
governors directory in cpu/cpu*/cpufreq/<gov> for platforms which have multiple
struct policy alive at any moment. Platform drivers requiring this feature must
set have_governor_per_policy variable in their instance of cpufreq_driver. For
others the interface is kept same: cpu/cpufreq/<gov>.


This is V4 of this patchset. V3 is already applied by Rafael in his linux-next
branch. Jacob Shin reported some regressions with this patchset and when I went
into testing it with his configuration I found more issues then what he
reported.

To test these over linux-next you need to revert following first:
db9baec cpufreq: Get rid of "struct global_attr"
86bd6f0 cpufreq: governor: Implement per policy instances of governors
8ae67b1 cpufreq: Add per policy governor-init/exit infrastructure

I have tested this for following now and believe there are no more regressions
with it:
- platform with a single policy instance or single group of cpu
- platform with multiple policies but which don't want per policy instance of
  governor
- platform with multiple policies and which want per policy instance of governor

I have tried with different settings and combinations of governors.

@Rafael: To simplify your life I have sorted out your branch and you can simply
pickup the complete branch that I have pushed.

V3->V4:
- We have two instances of all show/store routines for ondemand/conservative
  governor. One for per-policy instance of governor and other for one governor
  instance for all policies.
- Dropped: db9baec cpufreq: Get rid of "struct global_attr".
- Fixed cpufreq_governor_dbs for multiple policies using same governor instance.
- Implemented few macro's in cpufreq_governor.h to make above stuff clean.
- Renamed have_multiple_policies to have_governor_per_policy
- Some more minor cleanups

Viresh Kumar (2):
  cpufreq: Add per policy governor-init/exit infrastructure
  cpufreq: governor: Implement per policy instances of governors

 drivers/cpufreq/cpufreq.c              |  36 ++++-
 drivers/cpufreq/cpufreq_conservative.c | 193 ++++++++++++++----------
 drivers/cpufreq/cpufreq_governor.c     | 212 +++++++++++++++++---------
 drivers/cpufreq/cpufreq_governor.h     | 117 +++++++++++++--
 drivers/cpufreq/cpufreq_ondemand.c     | 263 ++++++++++++++++++++-------------
 include/linux/cpufreq.h                |  17 ++-
 6 files changed, 562 insertions(+), 276 deletions(-)

-- 
1.7.12.rc2.18.g61b472e