lkml.org 
[lkml]   [2014]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 1/2] cpufreq: Add stop callback to cpufreq_driver interface
Date
On Wednesday, March 19, 2014 11:31:31 PM Rafael J. Wysocki wrote:
> On Wednesday, March 19, 2014 08:45:53 AM dirk.brandewie@gmail.com wrote:
> > From: Dirk Brandewie <dirk.j.brandewie@intel.com>
> >
> > This callback allows the driver to do clean up before the CPU is
> > completely down and its state cannot be modified. This is used
> > by the intel_pstate driver to reduce the requested P state prior to
> > the core going away. This is required because the requested P state
> > of the offline core is used to select the package P state. This
> > effectively sets the floor package P state to the requested P state on
> > the offline core.
> >
> > Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>

To speed up things a bit I changed the name of the new callback to ->stop_cpu
and made it void.

I also modified patch [2/2] accordingly and queued the both of them up for 3.15.

Please check the bleeding-edge branch.

I wouldn't like to need to do anything like that any more in the future, though.

> > ---
> > Documentation/cpu-freq/cpu-drivers.txt | 8 +++++++-
> > drivers/cpufreq/cpufreq.c | 3 ++-
> > include/linux/cpufreq.h | 1 +
> > 3 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
> > index 8b1a445..79def80 100644
> > --- a/Documentation/cpu-freq/cpu-drivers.txt
> > +++ b/Documentation/cpu-freq/cpu-drivers.txt
> > @@ -61,7 +61,13 @@ target_index - See below on the differences.
> >
> > And optionally
> >
> > -cpufreq_driver.exit - A pointer to a per-CPU cleanup function.
> > +cpufreq_driver.exit - A pointer to a per-CPU cleanup
> > + function called during CPU_POST_DEAD
> > + phase of cpu hotplug process.
> > +
> > +cpufreq_driver.stop - A pointer to a per-CPU stop function
> > + called during CPU_DOWN_PREPARE phase of
> > + cpu hotplug process.
> >
> > cpufreq_driver.resume - A pointer to a per-CPU resume function
> > which is called with interrupts disabled
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index cf485d9..bb20292 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -1336,7 +1336,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
> > __func__, new_cpu, cpu);
> > }
> > }
> > - }
> > + } else if (cpufreq_driver->stop && cpufreq_driver->setpolicy)
> > + cpufreq_driver->stop(policy);
>
> Nit: Why is it an int function if the only caller doesn't check the
> return value? It should be void.
>
> >
> > return 0;
> > }
> > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> > index 4d89e0e..ff8db19 100644
> > --- a/include/linux/cpufreq.h
> > +++ b/include/linux/cpufreq.h
> > @@ -224,6 +224,7 @@ struct cpufreq_driver {
> > int (*bios_limit) (int cpu, unsigned int *limit);
> >
> > int (*exit) (struct cpufreq_policy *policy);
> > + int (*stop) (struct cpufreq_policy *policy);
> > int (*suspend) (struct cpufreq_policy *policy);
> > int (*resume) (struct cpufreq_policy *policy);
> > struct freq_attr **attr;
> >
>
>

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.


\
 
 \ /
  Last update: 2014-03-20 04:41    [W:0.043 / U:14.772 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site