Re: [PATCH V4 0/3] cpufreq: Allow default governor on cmdline and fix locking issues

[Rafael J. Wysocki]

On Mon, Jun 29, 2020 at 10:58 PM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
>
> Hi,
>
> I have picked Quentin's series over my patch, modified both and tested.
>
> V3->V4:
> - Do __module_get() for cpufreq_default_governor() case as well and get
>   rid of an extra variable.
> - Use a single character array, default_governor, instead of two of them.
>
> V2->V3:
> - default_governor is a string now and we don't set it on governor
>   registration or unregistration anymore.
> - Fixed locking issues in cpufreq_init_policy().
>
> --
> Viresh
>
> Original cover letter fro Quentin:
>
> This series enables users of prebuilt kernels (e.g. distro kernels) to
> specify their CPUfreq governor of choice using the kernel command line,
> instead of having to wait for the system to fully boot to userspace to
> switch using the sysfs interface. This is helpful for 2 reasons:
>   1. users get to choose the governor that runs during the actual boot;
>   2. it simplifies the userspace boot procedure a bit (one less thing to
>      worry about).
>
> To enable this, the first patch moves all governor init calls to
> core_initcall, to make sure they are registered by the time the drivers
> probe. This should be relatively low impact as registering a governor
> is a simple procedure (it gets added to a llist), and all governors
> already load at core_initcall anyway when they're set as the default
> in Kconfig. This also allows to clean-up the governors' init/exit code,
> and reduces boilerplate.
>
> The second patch introduces the new command line parameter, inspired by
> its cpuidle counterpart. More details can be found in the respective
> patch headers.
>
> Changes in v2:
>  - added Viresh's ack to patch 01
>  - moved the assignment of 'default_governor' in patch 02 to the governor
>    registration path instead of the driver registration (Viresh)
>
> Quentin Perret (2):
>   cpufreq: Register governors at core_initcall
>   cpufreq: Specify default governor on command line
>
> Viresh Kumar (1):
>   cpufreq: Fix locking issues with governors
>
>  .../admin-guide/kernel-parameters.txt         |  5 ++
>  Documentation/admin-guide/pm/cpufreq.rst      |  6 +-
>  .../platforms/cell/cpufreq_spudemand.c        | 26 +-----
>  drivers/cpufreq/cpufreq.c                     | 87 ++++++++++++-------
>  drivers/cpufreq/cpufreq_conservative.c        | 22 ++---
>  drivers/cpufreq/cpufreq_ondemand.c            | 24 ++---
>  drivers/cpufreq/cpufreq_performance.c         | 14 +--
>  drivers/cpufreq/cpufreq_powersave.c           | 18 +---
>  drivers/cpufreq/cpufreq_userspace.c           | 18 +---
>  include/linux/cpufreq.h                       | 14 +++
>  kernel/sched/cpufreq_schedutil.c              |  6 +-
>  11 files changed, 100 insertions(+), 140 deletions(-)
>
> --

All three patches applied as 5.9 material, thanks!