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Message-ID: <jhjmu97ygk9.fsf@arm.com>
Date: Mon, 24 Feb 2020 18:40:38 +0000
From: Valentin Schneider <valentin.schneider@....com>
To: Ionela Voinescu <ionela.voinescu@....com>
Cc: catalin.marinas@....com, will@...nel.org, mark.rutland@....com,
maz@...nel.org, suzuki.poulose@....com, sudeep.holla@....com,
lukasz.luba@....com, dietmar.eggemann@....com, rjw@...ysocki.net,
peterz@...radead.org, mingo@...hat.com, vincent.guittot@...aro.org,
viresh.kumar@...aro.org, linux-arm-kernel@...ts.infradead.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org
Subject: Re: [PATCH v4 6/7] arm64: use activity monitors for frequency invariance
Ionela Voinescu writes:
> Signed-off-by: Ionela Voinescu <ionela.voinescu@....com>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Will Deacon <will@...nel.org>
> Cc: Sudeep Holla <sudeep.holla@....com>
With the small nits below:
Reviewed-by: Valentin Schneider <valentin.schneider@....com>
> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
> index fa9528dfd0ce..7606cbd63517 100644
> --- a/arch/arm64/kernel/topology.c
> +++ b/arch/arm64/kernel/topology.c
> +
> +static inline int
That should be bool, seeing what it returns.
> +enable_policy_freq_counters(int cpu, cpumask_var_t valid_cpus)
> +{
> + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> +
> + if (!policy) {
> + pr_debug("CPU%d: No cpufreq policy found.\n", cpu);
> + return false;
> + }
> +
> + if (cpumask_subset(policy->related_cpus, valid_cpus))
> + cpumask_or(amu_fie_cpus, policy->related_cpus,
> + amu_fie_cpus);
> +
> + cpufreq_cpu_put(policy);
> +
> + return true;
> +}
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 1eb81f113786..1ab2b7503d63 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -29,6 +29,14 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
> unsigned long scale;
> int i;
>
> + /*
> + * If the use of counters for FIE is enabled, just return as we don't
> + * want to update the scale factor with information from CPUFREQ.
> + * Instead the scale factor will be updated from arch_scale_freq_tick.
> + */
> + if (arch_cpu_freq_counters(cpus))
> + return;
> +
> scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
>
> for_each_cpu(i, cpus)
> diff --git a/include/linux/topology.h b/include/linux/topology.h
> index eb2fe6edd73c..397aad6ae163 100644
> --- a/include/linux/topology.h
> +++ b/include/linux/topology.h
> @@ -227,5 +227,12 @@ static inline const struct cpumask *cpu_cpu_mask(int cpu)
> return cpumask_of_node(cpu_to_node(cpu));
> }
>
> +#ifndef arch_cpu_freq_counters
> +static __always_inline
> +bool arch_cpu_freq_counters(struct cpumask *cpus)
> +{
> + return false;
> +}
> +#endif
>
Apologies for commenting on this only now, I had missed it in my earlier
round of review.
I would've liked to keep this contained within arm64 stuff until we agreed
on a more generic counter-driven FIE interface, but seems like we can't evade
it due to the arch_topology situation.
Would it make sense to relocate this stub to arch_topology.h instead, at
least for the time being? That way the only non-arm64 changes are condensed
in arch_topology (even if it doesn't change much in terms of header files,
since topology.h imports arch_topology.h)
> #endif /* _LINUX_TOPOLOGY_H */
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