Messages in this thread | | | From | Daniel Kurtz <> | Date | Fri, 28 Aug 2015 10:18:20 +0800 | Subject | Re: [PATCH v4 4/5] thermal: power_allocator: don't require tzp to be present for the thermal zone |
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On Wed, Aug 26, 2015 at 9:26 PM, Javi Merino <javi.merino@arm.com> wrote: > Thermal zones created using thermal_zone_device_create() may not have > tzp. As the governor gets its parameters from there, allocate it while > the governor is bound to the thermal zone so that it can operate in it. > In this case, tzp is freed when the thermal zone switches to another > governor. > > Cc: Zhang Rui <rui.zhang@intel.com> > Cc: Eduardo Valentin <edubezval@gmail.com> > Signed-off-by: Javi Merino <javi.merino@arm.com> > --- > > While this would be easier to do by just ignoring the thermal zone if > there was no tzp, I think the approach in this patch provides a better > behavior.
Why? Just ignoring the thermal zone seems reasonable and simpler.
> > drivers/thermal/power_allocator.c | 32 +++++++++++++++++++++++++++----- > 1 file changed, 27 insertions(+), 5 deletions(-) > > diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c > index 2dfb8ade4d1b..85ce0aac9a41 100644 > --- a/drivers/thermal/power_allocator.c > +++ b/drivers/thermal/power_allocator.c > @@ -58,6 +58,8 @@ static inline s64 div_frac(s64 x, s64 y) > > /** > * struct power_allocator_params - parameters for the power allocator governor > + * @allocated_tzp: whether we have allocated tzp for this thermal zone and > + * it needs to be freed on unbind > * @err_integral: accumulated error in the PID controller. > * @prev_err: error in the previous iteration of the PID controller. > * Used to calculate the derivative term. > @@ -70,6 +72,7 @@ static inline s64 div_frac(s64 x, s64 y) > * controlling for. > */ > struct power_allocator_params { > + bool allocated_tzp; > s64 err_integral; > s32 prev_err; > int trip_switch_on; > @@ -530,8 +533,7 @@ static void allow_maximum_power(struct thermal_zone_device *tz) > * Initialize the PID controller parameters and bind it to the thermal > * zone. > * > - * Return: 0 on success, -EINVAL if the thermal zone doesn't have tzp or -ENOMEM > - * if we ran out of memory. > + * Return: 0 on success, or -ENOMEM if we ran out of memory. > */ > static int power_allocator_bind(struct thermal_zone_device *tz) > { > @@ -539,13 +541,20 @@ static int power_allocator_bind(struct thermal_zone_device *tz) > struct power_allocator_params *params; > unsigned long control_temp; > > - if (!tz->tzp) > - return -EINVAL; > - > params = kzalloc(sizeof(*params), GFP_KERNEL); > if (!params) > return -ENOMEM; > > + if (!tz->tzp) { > + tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);
Why bother to allocate this dummy struct? Can't we just leave tz->tzp as NULL, and do a NULL check where needed?
> + if (!tz->tzp) { > + ret = -ENOMEM; > + goto free_params; > + } > + > + params->allocated_tzp = true; > + } > + > if (!tz->tzp->sustainable_power) > dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n"); > > @@ -562,11 +571,24 @@ static int power_allocator_bind(struct thermal_zone_device *tz) > tz->governor_data = params; > > return 0; > + > +free_params: > + kfree(params); > + > + return ret; > } > > static void power_allocator_unbind(struct thermal_zone_device *tz) > { > + struct power_allocator_params *params = tz->governor_data; > + > dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id); > + > + if (params->allocated_tzp) { > + kfree(tz->tzp); > + tz->tzp = NULL; > + } > + > kfree(tz->governor_data); > tz->governor_data = NULL; > } > -- > 1.9.1 >
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