cpufreq: schedutil: Don't set next_freq to UINT_MAX
The schedutil driver sets sg_policy->next_freq to UINT_MAX on certain occasions to discard the cached value of next freq: - In sugov_start(), when the schedutil governor is started for a group of CPUs. - And whenever we need to force a freq update before rate-limit duration, which happens when: - there is an update in cpufreq policy limits. - Or when the utilization of DL scheduling class increases. In return, get_next_freq() doesn't return a cached next_freq value but recalculates the next frequency instead. But having special meaning for a particular value of frequency makes the code less readable and error prone. We recently fixed a bug where the UINT_MAX value was considered as valid frequency in sugov_update_single(). All we need is a flag which can be used to discard the value of sg_policy->next_freq and we already have need_freq_update for that. Lets reuse it instead of setting next_freq to UINT_MAX. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -95,15 +95,8 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
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if (sg_policy->work_in_progress)
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return false;
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if (unlikely(sg_policy->need_freq_update)) {
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sg_policy->need_freq_update = false;
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/*
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* This happens when limits change, so forget the previous
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* next_freq value and force an update.
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*/
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sg_policy->next_freq = UINT_MAX;
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if (unlikely(sg_policy->need_freq_update))
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return true;
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}
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delta_ns = time - sg_policy->last_freq_update_time;
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@ -165,8 +158,10 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
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freq = (freq + (freq >> 2)) * util / max;
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if (freq == sg_policy->cached_raw_freq && sg_policy->next_freq != UINT_MAX)
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if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
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return sg_policy->next_freq;
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sg_policy->need_freq_update = false;
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sg_policy->cached_raw_freq = freq;
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return cpufreq_driver_resolve_freq(policy, freq);
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}
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@ -305,8 +300,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
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* Do not reduce the frequency if the CPU has not been idle
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* recently, as the reduction is likely to be premature then.
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*/
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if (busy && next_f < sg_policy->next_freq &&
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sg_policy->next_freq != UINT_MAX) {
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if (busy && next_f < sg_policy->next_freq) {
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next_f = sg_policy->next_freq;
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/* Reset cached freq as next_freq has changed */
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@ -654,7 +648,7 @@ static int sugov_start(struct cpufreq_policy *policy)
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sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
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sg_policy->last_freq_update_time = 0;
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sg_policy->next_freq = UINT_MAX;
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sg_policy->next_freq = 0;
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sg_policy->work_in_progress = false;
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sg_policy->need_freq_update = false;
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sg_policy->cached_raw_freq = 0;
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