Message ID | 20240417093848.1555462-2-beata.michalska@arm.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | Add support for AArch64 AMUv1-based arch_freq_get_on_cpu | expand |
On Wed, Apr 17, 2024 at 10:38:44AM +0100, Beata Michalska wrote: > From: Ionela Voinescu <ionela.voinescu@arm.com> > > It's useful to have capacity_freq_ref initialized to 0 for users of > arch_scale_freq_ref() to detect when capacity_freq_ref was not > yet set. > > The only scenario affected by this change in the init value is when a > cpufreq driver is never loaded. As a result, the only setter of a > cpu scale factor remains the call of topology_normalize_cpu_scale() > from parse_dt_topology(). There we cannot use the value 0 of > capacity_freq_ref so we have to compensate for its uninitialized state. > Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 024b78a0cfc1..7d4c92cd2bad 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -27,7 +27,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; -DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 1; +DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 0; EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref); static bool supports_scale_freq_counters(const struct cpumask *cpus) @@ -292,13 +292,15 @@ void topology_normalize_cpu_scale(void) capacity_scale = 1; for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity_scale = max(capacity, capacity_scale); } pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale); for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, capacity_scale); topology_set_cpu_scale(cpu, capacity);