Messages in this thread | | | Date | Wed, 06 Apr 2016 14:29:21 -0700 | From | Saravana Kannan <> | Subject | Re: [PATCH 1/7] cpufreq: remove redundant CPUFREQ_INCOMPATIBLE notifier event |
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On 04/06/2016 02:21 PM, Rafael J. Wysocki wrote: > On Wed, Apr 6, 2016 at 10:30 PM, Saravana Kannan <skannan@codeaurora.org> wrote: >> On 09/09/2015 05:53 PM, Rafael J. Wysocki wrote: >>> >>> Hi, >>> >>> On Thu, Sep 10, 2015 at 2:39 AM, Viresh Kumar <viresh.kumar@linaro.org> >>> wrote: >>>> >>>> On 10-09-15, 01:26, Rafael J. Wysocki wrote: >>>>> >>>>> On Monday, August 03, 2015 08:36:14 AM Viresh Kumar wrote: >>>>>> >>>>>> What's being done from CPUFREQ_INCOMPATIBLE, can also be done with >>>>>> CPUFREQ_ADJUST. There is nothing special with CPUFREQ_INCOMPATIBLE >>>>>> notifier. >>>>> >>>>> >>>>> The above part of the changelog is a disaster to me. :-( >>>>> >>>>> It not only doesn't explain what really goes on, but it's actively >>>>> confusing. >>>>> >>>>> What really happens is that the core sends CPUFREQ_INCOMPATIBLE >>>>> notifications >>>>> unconditionally right after sending the CPUFREQ_ADJUST ones, so the >>>>> former is >>>>> just redundant and it's more efficient to merge the two into one. >>>> >>>> >>>> Undoubtedly this looks far better :) >>>> >>>> But, isn't this series already applied some time back ? >>> >>> >>> Right, never mind. For some reason that patch was left in the "New" >>> state. >>> >>> The code is OK. >> >> >> >> I guess I didn't notice this change when it was sent out. >> >> The comment that was deleted in this patch clearly states why the >> INCOMPATIBLE notifier is needed. Some client might want to boost the CPU min >> freq for performance or other reasons, but thermal might want to limit it. >> So, by having thermal register for INCOMPATIBLE notifiers to enforce the >> limits, we provide a way to guarantee it gets the final say. >> >> The real fix should have been to change drivers/thermal/cpu_cooling.c to use >> CPUFREQ_INCOMPATIBLE instead of CPUFREQ_ADJUST. >> >> Is there something I'm missing? If not, can we please revert this patch? > > Well, nobody was using that event. >
True, but that's more of a bug in drivers/thermal/cpu-cooling.c and drivers/acpi/processor_thermal.c. We should revert this patch and fix those drivers. Does that seem acceptable to you?
-Saravana
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