From: Zihuan Zhang Date: Fri, 25 Jul 2025 04:14:50 +0000 (+0800) Subject: cpufreq: Avoid calling get_governor() for first policy X-Git-Tag: v6.18-rc1~152^2~5^2~5^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5746dc1898a1bd5518a03081dc7e380569e269d;p=thirdparty%2Fkernel%2Flinux.git cpufreq: Avoid calling get_governor() for first policy When a cpufreq driver registers the first policy, it may attempt to initialize the policy governor from `last_governor`. However, this is meaningless for the first policy instance, because `last_governor` is only updated when policies are removed (e.g. during CPU offline). The `last_governor` mechanism is intended to restore the previously used governor across CPU hotplug events. For the very first policy, there is no "previous governor" to restore, so calling get_governor(last_governor) is unnecessary and potentially confusing. Skip looking up `last_governor` when registering the first policy. Instead, it directly uses the default governor after all governors have been registered and are available. This avoids meaningless lookups, reduces unnecessary module reference handling, and simplifies the initial policy path. Signed-off-by: Zihuan Zhang Acked-by: Viresh Kumar Reviewed-by: Lifeng Zheng Link: https://patch.msgid.link/20250725041450.68754-1-zhangzihuan@kylinos.cn [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index fc7eace8b65be..b8937737d0967 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1121,7 +1121,8 @@ static int cpufreq_init_policy(struct cpufreq_policy *policy) if (has_target()) { /* Update policy governor to the one used before hotplug. */ - gov = get_governor(policy->last_governor); + if (policy->last_governor[0] != '\0') + gov = get_governor(policy->last_governor); if (gov) { pr_debug("Restoring governor %s for cpu %d\n", gov->name, policy->cpu);