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Commit 87c3e8e7 authored by John Dias's avatar John Dias Committed by DarkJoker360
Browse files

cpufreq: schedutil: clear cached_raw_freq when invalidated 



The cpufreq_schedutil governor keeps a cache of the last
raw frequency that was mapped to a supported device frequency.
If the next request for a frequency matches the cached
value, the policy's next_freq value is reused. But there
are paths that can update the raw cached value without
updating the next_freq value, and there are paths that
can set the next_freq value without setting the raw
cached value. On those paths, the cached value
must be reset.

The case that has been observed is when a frequency request
reaches sugov_update_commit but is then rejected by to
the sugov_up_down_rate_limit check.

Bug: 116279565
Change-Id: I7c585339a04ff1732054d6e5b36a57e2d41266aa
Signed-off-by: default avatarJohn Dias <joaodias@google.com>
Signed-off-by: default avatarMiguel de Dios <migueldedios@google.com>
Signed-off-by: default avatarAlexander Winkowski <dereference23@outlook.com>
parent 5edd0045

kernel/sched/cpufreq_schedutil.c

+15 −4
Original line number Diff line number Diff line
@@ -162,8 +162,11 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, 
	if (sg_policy->next_freq == next_freq)

		return;



	if (sugov_up_down_rate_limit(sg_policy, time, next_freq))

	if (sugov_up_down_rate_limit(sg_policy, time, next_freq)) {

		/* Don't cache a raw freq that didn't become next_freq */

		sg_policy->cached_raw_freq = 0;

		return;

	}



	sg_policy->next_freq = next_freq;

	sg_policy->last_freq_update_time = time;
@@ -331,6 +334,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, 
	busy = use_pelt() && sugov_cpu_is_busy(sg_cpu);



	if (flags & SCHED_CPUFREQ_RT_DL) {

		/* clear cache when it's bypassed */

		sg_policy->cached_raw_freq = 0;

		next_f = policy->cpuinfo.max_freq;

	} else {

		sugov_get_util(&util, &max, sg_cpu->cpu);
@@ -377,8 +382,11 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) 
			j_sg_cpu->iowait_boost_pending = false;

			continue;

		}

		if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)

		if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL) {

			/* clear cache when it's bypassed */

			sg_policy->cached_raw_freq = 0;

			return policy->cpuinfo.max_freq;

		}



		j_util = j_sg_cpu->util;

		j_max = j_sg_cpu->max;
@@ -419,10 +427,13 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, 


	if (sugov_should_update_freq(sg_policy, time) &&

		!(flags & SCHED_CPUFREQ_CONTINUE)) {

		if (flags & SCHED_CPUFREQ_RT_DL)

		if (flags & SCHED_CPUFREQ_RT_DL) {

			next_f = sg_policy->policy->cpuinfo.max_freq;

		else

			/* clear cache when it's bypassed */

			sg_policy->cached_raw_freq = 0;

		} else {

			next_f = sugov_next_freq_shared(sg_cpu, time);

		}



		sugov_update_commit(sg_policy, time, next_f);

	}