From: Rafael J. Wysocki Date: Tue, 7 Jul 2026 17:25:39 +0000 (+0200) Subject: cpufreq: Make cpufreq_update_pressure() fall back to cpuinfo.max_freq X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d2d5c129d07ea8eb91cd8a8633b5774116c4d171;p=thirdparty%2Fkernel%2Flinux.git cpufreq: Make cpufreq_update_pressure() fall back to cpuinfo.max_freq If arch_scale_freq_ref() is not defined for a given arch (like x86, for example), cpufreq_update_pressure() will always set cpufreq_pressure to zero for all CPUs in the system, which is generally problematic on systems with asymmetric capacity [1]. However, in the absence of arch_scale_freq_ref(), it is reasonable to assume that cpuinfo.max_freq is the maximum sustainable frequency for the given cpufreq policy. Moreover, there are cases in which arch_scale_freq_ref() would need to be defined to return essentially the cpuinfo.max_freq value anyway (for example, intel_pstate on hybrid platforms). For the above reasons, update cpufreq_update_pressure() to fall back to using cpuinfo.max_freq as the reference frequency if zero is returned by arch_scale_freq_ref(). Fixes: 75d659317bb1 ("cpufreq: Add a cpufreq pressure feedback for the scheduler") Link: https://lore.kernel.org/lkml/CAKfTPtBuRLfYNnR4w--cFZYZy-R8gaPEgVwCcaMmbCcJ2H-muQ@mail.gmail.com/ [1] Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Reviewed-by: Zhongqiu Han Tested-by: Ricardo Neri # cluster scheduling Acked-by: Vincent Guittot Link: https://patch.msgid.link/5086499.GXAFRqVoOG@rafael.j.wysocki --- diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 507224c9ecd3..b898b6544069 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2586,6 +2586,9 @@ static void cpufreq_update_pressure(struct cpufreq_policy *policy) cpu = cpumask_first(policy->related_cpus); max_freq = arch_scale_freq_ref(cpu); + if (!max_freq) + max_freq = policy->cpuinfo.max_freq; + capped_freq = policy->max; /*