linux-kernel - Re: [PATCH V3 3/3] arm64: topology: Make AMUs work with modular cpufreq drivers

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Message-ID: <20201215115605.GB25331@arm.com>
Date:   Tue, 15 Dec 2020 11:56:05 +0000
From:   Ionela Voinescu <ionela.voinescu@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V3 3/3] arm64: topology: Make AMUs work with modular
 cpufreq drivers

Hi,

On Tuesday 15 Dec 2020 at 11:04:16 (+0530), Viresh Kumar wrote:
> The AMU counters won't get used today if the cpufreq driver is built as
> a module as the amu core requires everything to be ready by late init.
> 
> Fix that properly by registering for cpufreq policy notifier. Note that
> the amu core don't have any cpufreq dependency after the first time
> CPUFREQ_CREATE_POLICY notifier is called for all the CPUs. And so we
> don't need to do anything on the CPUFREQ_REMOVE_POLICY notifier. And for
> the same reason we check if the CPUs are already parsed in the beginning
> of amu_fie_setup() and skip if that is true. Alternatively we can shoot
> a work from there to unregister the notifier instead, but that seemed
> too much instead of this simple check.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> V3:
> - This is a new patch.
> 
> Ionela,
> 
> I don't have a way to test the AMU stuff, will it be possible for you to
> give it a try ?
> 

I'll review this new patch and then I'll give the full set a try.

Thanks for the interest in improving this,
Ionela.