On 14/05/2021 11:53, Ionela Voinescu wrote:
[...]
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index c1179edc0f3b..f710d64f125b 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -291,6 +291,45 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
> return !ret;
> }
>
> +#ifdef CONFIG_ACPI_CPPC_LIB
> +#include <acpi/cppc_acpi.h>
init_cpu_capacity_cppc() shares a lot of functionality with the existing
DT/CPUfreq-based approach (topology_parse_cpu_capacity(),
register_cpufreq_notifier(), init_cpu_capacity_callback()). It looks
like that the different ways of invocation (two steps per cpu vs. one
step for all cpus) makes it hard to restructure the code to create more
common bits.
> +void init_cpu_capacity_cppc(void)
> +{
> + struct cppc_perf_caps perf_caps;
> + int cpu;
> +
> + if (likely(acpi_disabled || !acpi_cpc_valid()))
likely(acpi_disabled) ?
> + return;
> +
> + raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity),
> + GFP_KERNEL);
> + if (!raw_capacity)
> + return;
> +
> + for_each_possible_cpu(cpu) {
> + if (!cppc_get_perf_caps(cpu, &perf_caps)) {
> + raw_capacity[cpu] = perf_caps.highest_perf;
> + pr_debug("%s: CPU%d cpu_capacity=%u (raw).\n",
> + __func__, cpu, raw_capacity[cpu]);
There is quite a variety in the layout of the pr_xxx() log messages in
this file. Originally the 'cpu_capacity:' was used to indicate that this
log is from drivers/base/arch_topology.c. Now the GCC __func__
identifier is used. Maybe this can be aligned better? Especially since
the functionality used in the existing DT-driven and now in the new
CPPC-driven functionality is quite similar. Debugging is so much easier
with consistent log strings.
> + } else {
> + pr_err("%s: CPU%d missing highest performance.\n",
> + __func__, cpu);
> + pr_err("%s: fallback to 1024 for all CPUs\n",
> + __func__);
> + goto exit;
> + }
> + }
> +
> + topology_normalize_cpu_scale();
> + schedule_work(&update_topology_flags_work);
> + pr_debug("%s: cpu_capacity initialization done\n", __func__);
> +
> +exit:
> + free_raw_capacity();
> +}
> +#endif
In case a system has CONFIG_ACPI_CPPC_LIB what does this mean for the
DT-based approach via `register_cpufreq_notifier()`?
Looks like we rely on:
376 static int __init register_cpufreq_notifier(void)
...
385 if (!acpi_disabled || ...)
386 return -EINVAL;
to disable the CPUfreq part of the DT/CPUfreq-based approach on an ACPI
system.
[...]
