From 80b120ca1a75c2df093d15936ab0591d90c99de9 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 23 Mar 2017 00:00:47 +0100 Subject: [PATCH] cpufreq: intel_pstate: Avoid transient updates of cpuinfo.max_freq Both intel_pstate_verify_policy() and intel_cpufreq_verify_policy() set policy->cpuinfo.max_freq depending on the turbo status, but the updates made by them are discarded by the core, because the policy object passed to them by the core is temporary and cpuinfo.max_freq from that object is not copied to the final policy object in cpufreq_set_policy(). However, cpufreq_set_policy() passes the temporary policy object to the ->setpolicy callback of the driver, so intel_pstate_set_policy() actually sees the policy->cpuinfo.max_freq value updated by intel_pstate_verify_policy() and not the final one. It also updates policy->max sometimes which basically has no effect after it returns, because the core discards that update. To avoid confusion, eliminate policy->cpuinfo.max_freq updates from intel_pstate_verify_policy() and intel_cpufreq_verify_policy() entirely and check the maximum frequency explicitly in intel_pstate_update_perf_limits() instead of relying on the transiently updated policy->cpuinfo.max_freq value. Moreover, move the max->policy adjustment carried out in intel_pstate_set_policy() to a separate function and call that function from the ->verify driver callbacks to ensure that it will actually be effective. Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 47 +++++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 19 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index c0afa78..60544c2 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2021,19 +2021,25 @@ static void intel_pstate_clear_update_util_hook(unsigned int cpu) synchronize_sched(); } +static int intel_pstate_get_max_freq(struct cpudata *cpu) +{ + return global.turbo_disabled || global.no_turbo ? + cpu->pstate.max_freq : cpu->pstate.turbo_freq; +} + static void intel_pstate_update_perf_limits(struct cpufreq_policy *policy, struct cpudata *cpu) { struct perf_limits *limits = &cpu->perf_limits; + int max_freq = intel_pstate_get_max_freq(cpu); int32_t max_policy_perf, min_policy_perf; - max_policy_perf = div_ext_fp(policy->max, policy->cpuinfo.max_freq); + max_policy_perf = div_ext_fp(policy->max, max_freq); max_policy_perf = clamp_t(int32_t, max_policy_perf, 0, int_ext_tofp(1)); if (policy->max == policy->min) { min_policy_perf = max_policy_perf; } else { - min_policy_perf = div_ext_fp(policy->min, - policy->cpuinfo.max_freq); + min_policy_perf = div_ext_fp(policy->min, max_freq); min_policy_perf = clamp_t(int32_t, min_policy_perf, 0, max_policy_perf); } @@ -2048,7 +2054,7 @@ static void intel_pstate_update_perf_limits(struct cpufreq_policy *policy, /* Global limits are in percent of the maximum turbo P-state. */ global_max = percent_ext_fp(global.max_perf_pct); global_min = percent_ext_fp(global.min_perf_pct); - if (policy->cpuinfo.max_freq != cpu->pstate.turbo_freq) { + if (max_freq != cpu->pstate.turbo_freq) { int32_t turbo_factor; turbo_factor = div_ext_fp(cpu->pstate.turbo_pstate, @@ -2088,13 +2094,6 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) cpu = all_cpu_data[policy->cpu]; cpu->policy = policy->policy; - if (cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate && - policy->max < policy->cpuinfo.max_freq && - policy->max > cpu->pstate.max_pstate * cpu->pstate.scaling) { - pr_debug("policy->max > max non turbo frequency\n"); - policy->max = policy->cpuinfo.max_freq; - } - mutex_lock(&intel_pstate_limits_lock); intel_pstate_update_perf_limits(policy, cpu); @@ -2118,21 +2117,31 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) return 0; } +static void intel_pstate_adjust_policy_max(struct cpufreq_policy *policy, + struct cpudata *cpu) +{ + if (cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate && + policy->max < policy->cpuinfo.max_freq && + policy->max > cpu->pstate.max_freq) { + pr_debug("policy->max > max non turbo frequency\n"); + policy->max = policy->cpuinfo.max_freq; + } +} + static int intel_pstate_verify_policy(struct cpufreq_policy *policy) { struct cpudata *cpu = all_cpu_data[policy->cpu]; update_turbo_state(); - policy->cpuinfo.max_freq = global.turbo_disabled || global.no_turbo ? - cpu->pstate.max_freq : - cpu->pstate.turbo_freq; - - cpufreq_verify_within_cpu_limits(policy); + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + intel_pstate_get_max_freq(cpu)); if (policy->policy != CPUFREQ_POLICY_POWERSAVE && policy->policy != CPUFREQ_POLICY_PERFORMANCE) return -EINVAL; + intel_pstate_adjust_policy_max(policy, cpu); + return 0; } @@ -2227,10 +2236,10 @@ static int intel_cpufreq_verify_policy(struct cpufreq_policy *policy) struct cpudata *cpu = all_cpu_data[policy->cpu]; update_turbo_state(); - policy->cpuinfo.max_freq = global.no_turbo || global.turbo_disabled ? - cpu->pstate.max_freq : cpu->pstate.turbo_freq; + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + intel_pstate_get_max_freq(cpu)); - cpufreq_verify_within_cpu_limits(policy); + intel_pstate_adjust_policy_max(policy, cpu); intel_pstate_update_perf_limits(policy, cpu); -- 2.7.4