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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rafael Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
	linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH V2 5/5] cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update()
Date: Thu, 20 Jun 2019 08:35:50 +0530
Message-ID: <ea598384a9ba18e20b598863ce339a55093be5f6.1560999838.git.viresh.kumar@linaro.org> (raw)
In-Reply-To: <cover.1560999838.git.viresh.kumar@linaro.org>

On some occasions cpufreq_verify_current_freq() schedules a work whose
callback is handle_update(), which further calls cpufreq_update_policy()
which may end up calling cpufreq_verify_current_freq() again.

On the other hand, when cpufreq_update_policy() is called from
handle_update(), the pointer to the cpufreq policy is already available
but we still call cpufreq_cpu_acquire() to get it in
cpufreq_update_policy(), which should be avoided as well.

Fix both the issues by creating another helper
reeval_frequency_limits().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/cpufreq.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 4556a53fc764..0a73de7aae54 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1115,13 +1115,25 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
 	return ret;
 }
 
+static void reeval_frequency_limits(struct cpufreq_policy *policy)
+{
+	struct cpufreq_policy new_policy = *policy;
+
+	pr_debug("updating policy for CPU %u\n", policy->cpu);
+
+	new_policy.min = policy->user_policy.min;
+	new_policy.max = policy->user_policy.max;
+
+	cpufreq_set_policy(policy, &new_policy);
+}
+
 static void handle_update(struct work_struct *work)
 {
 	struct cpufreq_policy *policy =
 		container_of(work, struct cpufreq_policy, update);
-	unsigned int cpu = policy->cpu;
-	pr_debug("handle_update for cpu %u called\n", cpu);
-	cpufreq_update_policy(cpu);
+
+	pr_debug("handle_update for cpu %u called\n", policy->cpu);
+	reeval_frequency_limits(policy);
 }
 
 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
@@ -2378,7 +2390,6 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
 void cpufreq_update_policy(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
-	struct cpufreq_policy new_policy;
 
 	if (!policy)
 		return;
@@ -2391,12 +2402,7 @@ void cpufreq_update_policy(unsigned int cpu)
 	    (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
 		goto unlock;
 
-	pr_debug("updating policy for CPU %u\n", cpu);
-	memcpy(&new_policy, policy, sizeof(*policy));
-	new_policy.min = policy->user_policy.min;
-	new_policy.max = policy->user_policy.max;
-
-	cpufreq_set_policy(policy, &new_policy);
+	reeval_frequency_limits(policy);
 
 unlock:
 	cpufreq_cpu_release(policy);
-- 
2.21.0.rc0.269.g1a574e7a288b


      parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20  3:05 [PATCH V2 0/5] cpufreq: cleanups Viresh Kumar
2019-06-20  3:05 ` [PATCH V2 1/5] cpufreq: Remove the redundant !setpolicy check Viresh Kumar
2019-06-27 21:52   ` Rafael J. Wysocki
2019-06-20  3:05 ` [PATCH V2 2/5] cpufreq: Replace few CPUFREQ_CONST_LOOPS checks with has_target() Viresh Kumar
2019-06-27  5:00   ` Viresh Kumar
2019-06-27  9:52     ` Rafael J. Wysocki
2019-06-28  5:16   ` [PATCH V3 2/5] cpufreq: Don't skip frequency validation for has_target() drivers Viresh Kumar
2019-06-20  3:05 ` [PATCH V2 3/5] cpufreq: Use has_target() instead of !setpolicy Viresh Kumar
2019-06-27 21:52   ` Rafael J. Wysocki
2019-06-20  3:05 ` [PATCH V2 4/5] cpufreq: Reuse cpufreq_update_current_freq() in __cpufreq_get() Viresh Kumar
2019-06-20  3:05 ` Viresh Kumar [this message]

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