On Thursday 10 Dec 2020 at 21:59:22 (+0530), Viresh Kumar wrote: > Every time I have stumbled upon this routine, I get confused with the > way 'have_policy' is used and I have to dig in to understand why is it > so. Here is an attempt to make it easier to understand, and hopefully it > is an improvement. > > The 'have_policy' check was just an optimization to avoid writing > to amu_fie_cpus in case we don't have to, but that optimization itself > is creating more confusion than the real work. Lets just do that if all > the CPUs support AMUs. It is much cleaner that way. > > Signed-off-by: Viresh Kumar <[email protected]> > --- > V2: > - Skip the have_policy check altogether > - Updated subject and log > > arch/arm64/kernel/topology.c | 20 ++++++-------------- > 1 file changed, 6 insertions(+), 14 deletions(-) > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index f6faa697e83e..ebadc73449f9 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -199,14 +199,14 @@ static int freq_inv_set_max_ratio(int cpu, u64 > max_rate, u64 ref_rate) > return 0; > } > > -static inline bool > +static inline void > 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; > + return; > } > > if (cpumask_subset(policy->related_cpus, valid_cpus)) > @@ -214,8 +214,6 @@ enable_policy_freq_counters(int cpu, cpumask_var_t > valid_cpus) > amu_fie_cpus); > > cpufreq_cpu_put(policy); > - > - return true; > } > > static DEFINE_STATIC_KEY_FALSE(amu_fie_key); > @@ -225,7 +223,6 @@ static int __init init_amu_fie(void) > { > bool invariance_status = topology_scale_freq_invariant(); > cpumask_var_t valid_cpus; > - bool have_policy = false; > int ret = 0; > int cpu; > > @@ -245,17 +242,12 @@ static int __init init_amu_fie(void) > continue; > > cpumask_set_cpu(cpu, valid_cpus); > - have_policy |= enable_policy_freq_counters(cpu, valid_cpus); > + enable_policy_freq_counters(cpu, valid_cpus); > } > > - /* > - * If we are not restricted by cpufreq policies, we only enable > - * the use of the AMU feature for FIE if all CPUs support AMU. > - * Otherwise, enable_policy_freq_counters has already enabled > - * policy cpus. > - */ > - if (!have_policy && cpumask_equal(valid_cpus, cpu_present_mask)) > - cpumask_or(amu_fie_cpus, amu_fie_cpus, valid_cpus); > + /* Overwrite amu_fie_cpus if all CPUs support AMU */ > + if (cpumask_equal(valid_cpus, cpu_present_mask)) > + cpumask_copy(amu_fie_cpus, cpu_present_mask); > > if (!cpumask_empty(amu_fie_cpus)) { > pr_info("CPUs[%*pbl]: counters will be used for FIE.", > -- > 2.25.0.rc1.19.g042ed3e048af >
Reviewed-by: Ionela Voinescu <[email protected]> Thanks, Ionela.
