linux-kernel - Re: [PATCH v4 0/5] Refactor thermal pressure update to avoid code duplication

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Message-ID: <9f0c8d5c-7170-c6b8-33d6-cfc065c77972@arm.com>
Date:   Tue, 23 Nov 2021 09:46:02 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, steev@...i.org,
        sudeep.holla@....com, will@...nel.org, catalin.marinas@....com,
        linux@...linux.org.uk, gregkh@...uxfoundation.org,
        rafael@...nel.org, amitk@...nel.org, daniel.lezcano@...aro.org,
        amit.kachhap@...il.com, thara.gopinath@...aro.org,
        bjorn.andersson@...aro.org, agross@...nel.org
Subject: Re: [PATCH v4 0/5] Refactor thermal pressure update to avoid code
 duplication



On 11/23/21 9:45 AM, Viresh Kumar wrote:
> On 09-11-21, 19:57, Lukasz Luba wrote:
>> Hi all,
>>
>> This patch set v4 aims to refactor the thermal pressure update
>> code. There are already two clients which do similar thing:
>> convert the capped frequency value into the capacity of
>> affected CPU and call the 'set' function to store the
>> reduced capacity into the per-cpu variable.
>> There might be more than two of these users. In near future
>> it will be scmi-cpufreq driver, which receives notification
>> from FW about reduced frequency due to thermal. Other vendors
>> might follow. Let's avoid code duplication and potential
>> conversion bugs. Move the conversion code into the arch_topology.c
>> where the capacity calculation setup code and thermal pressure sit.
>>
>> Apart from that $subject patches, there is one patch (3/5) which fixes
>> issue in qcom-cpufreq-hw.c when the thermal pressure is not
>> updated for offline CPUs. It's similar fix that has been merged
>> recently for cpufreq_cooling.c:
>> 2ad8ccc17d1e4270cf65a3f2
>>
>> The patch 4/5 fixes also qcom-cpufreq-hw.c driver code which did
>> the translation from frequency to capacity wrongly when there
>> was a boost frequency available and stored in 'policy->cpuinfo.max_freq'.
>>
>> Changes:
>> v4:
>> - remove the warning when boost frequency is passed and set thermal
>>    pressure to 0 in that case, which means the capping is totally removed
>>    (issue reported by Steev)
>> - remove the check from patch 4/5 with
>>    'throttled_freq > policy->cpuinfo.max_freq' since it doesn't have
>>    effect; instead relay on new arch_update_thermal_pressure() handling
>>    correctly such use case; this would also fix an issue in that original
>>    driver code, where the reduced capacity was calculated wrongly due
>>    to 'policy->cpuinfo.max_freq' used as a divider
>> - adjusted comments stressing the fact that the boost frequencies are
>>    supported
> 
>> Lukasz Luba (5):
>>    arch_topology: Introduce thermal pressure update function
>>    thermal: cpufreq_cooling: Use new thermal pressure update function
>>    cpufreq: qcom-cpufreq-hw: Update offline CPUs per-cpu thermal pressure
>>    cpufreq: qcom-cpufreq-hw: Use new thermal pressure update function
>>    arch_topology: Remove unused topology_set_thermal_pressure() and
>>      related
>>
>>   arch/arm/include/asm/topology.h   |  2 +-
>>   arch/arm64/include/asm/topology.h |  2 +-
>>   drivers/base/arch_topology.c      | 42 ++++++++++++++++++++++++++++---
>>   drivers/cpufreq/qcom-cpufreq-hw.c | 14 +++--------
>>   drivers/thermal/cpufreq_cooling.c |  6 +----
>>   include/linux/arch_topology.h     |  4 +--
>>   include/linux/sched/topology.h    |  6 ++---
>>   init/Kconfig                      |  2 +-
>>   8 files changed, 50 insertions(+), 28 deletions(-)
> 
> Applied. Thanks.
> 

Thank you!