Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 1/2] cpufreq: Add stop callback to cpufreq_driver interface | Date | Thu, 20 Mar 2014 04:28:20 +0100 |
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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.
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