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acpi-cpufreq: use same acpi_cpufreq_data if policy is shared

PATCH In review Pan Xinhui 2 participants 2 messages Jul 3, 2015 CPU frequency scaling framework

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Pan Xinhui

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#0 lore raw

PATCH 1/1 acpi-cpufreq: use same acpi_cpufreq_data if policy is shared

cpufreq core will mark all cpus in policy->cpus as initialized by setting percpu cpufreq_cpu_data = policy.
However in acpi-cpufreq, we did not set percpu acpi_cpufreq_data for all cpus in policy->cpus.
That will cause a issue that when we call get_cur_freq_on_cpu for a cpu, it returns zero instead of a correct value.

So we shared acpi_cpufreq_data for all those cpus in policy->cpus.

Signed-off-by xinhuix.pan <[email protected]>
---
 drivers/cpufreq/acpi-cpufreq.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
drivers/cpufreq/acpi-cpufreq.c +12 -2
index 0136dfc..6c6dc97 100644
@@ -673,6 +673,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	}
 
 	data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
+	cpumask_copy(policy->cpus, cpumask_of(cpu));
 	per_cpu(acfreq_data, cpu) = data;
 
 	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))

@@ -712,6 +713,10 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	}
 #endif
 
+	for_each_cpu(i, policy->cpus) {
+		per_cpu(acfreq_data, i) = data;
+	}
+
 	/* capability check */
 	if (perf->state_count <= 1) {
 		pr_debug("No P-States\n");

@@ -843,7 +848,9 @@ err_free_mask:
 	free_cpumask_var(data->freqdomain_cpus);
 err_free:
 	kfree(data);
-	per_cpu(acfreq_data, cpu) = NULL;
+	for_each_cpu(i, policy->cpus) {
+		per_cpu(acfreq_data, i) = NULL;
+	}
 
 	return result;
 }

@@ -851,11 +858,14 @@ err_free:
 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 {
 	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
+	int i;
 
 	pr_debug("acpi_cpufreq_cpu_exit\n");
 
 	if (data) {
-		per_cpu(acfreq_data, policy->cpu) = NULL;
+		for_each_cpu(i, policy->cpus) {
+			per_cpu(acfreq_data, i) = NULL;
+		}
 		acpi_processor_unregister_performance(data->acpi_data,
 						      policy->cpu);
 		free_cpumask_var(data->freqdomain_cpus);
Signature · 1 line
1.9.1
maintainer
#1 lore raw
Quoted 20 lines · Pan Xinhui

cpufreq core will mark all cpus in policy->cpus as initialized by setting percpu cpufreq_cpu_data = policy.
However in acpi-cpufreq, we did not set percpu acpi_cpufreq_data for all cpus in policy->cpus.
That will cause a issue that when we call get_cur_freq_on_cpu for a cpu, it returns zero instead of a correct value.

So we shared acpi_cpufreq_data for all those cpus in policy->cpus.

Signed-off-by xinhuix.pan <[email protected]>
---
 drivers/cpufreq/acpi-cpufreq.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
drivers/cpufreq/acpi-cpufreq.c +0 -0
index 0136dfc..6c6dc97 100644

drivers/cpufreq/acpi-cpufreq.c static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) · line 676

Quoted 4 lines
drivers/cpufreq/acpi-cpufreq.c +1 -0
@@ -673,6 +673,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	}
 
 	data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
+	cpumask_copy(policy->cpus, cpumask_of(cpu));

This is already done by cpufreq-core before calling ->init() and so isn't required.

Quoted 15 lines
drivers/cpufreq/acpi-cpufreq.c +4 -0
 	per_cpu(acfreq_data, cpu) = data;
 
 	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))

@@ -712,6 +713,10 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	}
 #endif
 
+	for_each_cpu(i, policy->cpus) {
+		per_cpu(acfreq_data, i) = data;
+	}
+
 	/* capability check */
 	if (perf->state_count <= 1) {
 		pr_debug("No P-States\n");

drivers/cpufreq/acpi-cpufreq.c err_free_mask: · line 853

Quoted 7 lines
drivers/cpufreq/acpi-cpufreq.c +3 -1
@@ -843,7 +848,9 @@ err_free_mask:
 	free_cpumask_var(data->freqdomain_cpus);
 err_free:
 	kfree(data);
-	per_cpu(acfreq_data, cpu) = NULL;
+	for_each_cpu(i, policy->cpus) {
+		per_cpu(acfreq_data, i) = NULL;
+	}

The per-cpu thing is basically wrong to start with. cpufreq-policy has a field: 'driver_data', which can be used to replace this acfreq_data. Probably use that and things will get fixed by themselves.

Signature · 1 line
viresh