[PATCH v4 0/2] add SW BOOST support for CPPC

[PATCH v4 0/2] add SW BOOST support for CPPC

[Xiongfeng Wang]

ACPI spec 6.2 section 8.4.7.1 provide the following two CPC registers.

"Highest performance is the absolute maximum performance an individual
processor may reach, assuming ideal conditions. This performance level
may not be sustainable for long durations, and may only be achievable if
other platform components are in a specific state; for example, it may
require other processors be in an idle state.

Nominal Performance is the maximum sustained performance level of the
processor, assuming ideal operating conditions. In absence of an
external constraint (power, thermal, etc.) this is the performance level
the platform is expected to be able to maintain continuously. All
processors are expected to be able to sustain their nominal performance
state simultaneously."

We can use Highest Performance as the max performance in boost mode and
Nomial Performance as the max performance in non-boost mode. If the
Highest Performance is greater than the Nominal Performance, we assume
SW BOOST is supported.

v3->v4:
	run 'boost_set_msr_each' for each CPU in the policy rather than
	each CPU in the system for 'acpi-cpufreq'
	add 'Suggested-by'

Xiongfeng Wang (2):
  cpufreq: change '.set_boost' to act on only one policy
  CPPC: add support for SW BOOST

 drivers/cpufreq/acpi-cpufreq.c | 10 ++++----
 drivers/cpufreq/cppc_cpufreq.c | 39 +++++++++++++++++++++++++++++--
 drivers/cpufreq/cpufreq.c      | 53 +++++++++++++++++++++---------------------
 include/linux/cpufreq.h        |  2 +-
 4 files changed, 71 insertions(+), 33 deletions(-)

-- 
1.7.12.4

[PATCH v4 1/2] cpufreq: change '.set_boost' to act on only one policy

[Xiongfeng Wang]

Macro 'for_each_active_policy()' is defined internally. To avoid some
cpufreq driver needing this macro to iterate over all the policies in
'.set_boost' callback, we redefine '.set_boost' to act on only one
policy and pass the policy as an argument.
'cpufreq_boost_trigger_state()' iterate over all the policies to set
boost for the system. This is preparation for adding SW BOOST support
for CPPC.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/acpi-cpufreq.c | 10 ++++----
 drivers/cpufreq/cpufreq.c      | 53 +++++++++++++++++++++---------------------
 include/linux/cpufreq.h        |  2 +-
 3 files changed, 34 insertions(+), 31 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 289e8ce..813aabf 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -126,12 +126,14 @@ static void boost_set_msr_each(void *p_en)
 	boost_set_msr(enable);
 }
 
-static int set_boost(int val)
+static int set_boost(struct cpufreq_policy *policy, int val)
 {
 	get_online_cpus();
-	on_each_cpu(boost_set_msr_each, (void *)(long)val, 1);
+	on_each_cpu_mask(policy->cpus, boost_set_msr_each,
+			 (void *)(long)val, 1);
 	put_online_cpus();
-	pr_debug("Core Boosting %sabled.\n", val ? "en" : "dis");
+	pr_debug("CPU %*pbl: Core Boosting %sabled.\n",
+		 cpumask_pr_args(policy->cpus), val ? "en" : "dis");
 
 	return 0;
 }
@@ -162,7 +164,7 @@ static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
 	if (ret || val > 1)
 		return -EINVAL;
 
-	set_boost(val);
+	set_boost(policy, val);
 
 	return count;
 }
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index d03f250..d0d86b1 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2532,34 +2532,29 @@ void cpufreq_update_limits(unsigned int cpu)
 /*********************************************************************
  *               BOOST						     *
  *********************************************************************/
-static int cpufreq_boost_set_sw(int state)
+static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
 {
-	struct cpufreq_policy *policy;
-
-	for_each_active_policy(policy) {
-		int ret;
-
-		if (!policy->freq_table)
-			return -ENXIO;
+	int ret;
 
-		ret = cpufreq_frequency_table_cpuinfo(policy,
-						      policy->freq_table);
-		if (ret) {
-			pr_err("%s: Policy frequency update failed\n",
-			       __func__);
-			return ret;
-		}
+	if (!policy->freq_table)
+		return -ENXIO;
 
-		ret = freq_qos_update_request(policy->max_freq_req, policy->max);
-		if (ret < 0)
-			return ret;
+	ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
+	if (ret) {
+		pr_err("%s: Policy frequency update failed\n", __func__);
+		return ret;
 	}
 
+	ret = freq_qos_update_request(policy->max_freq_req, policy->max);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
 int cpufreq_boost_trigger_state(int state)
 {
+	struct cpufreq_policy *policy;
 	unsigned long flags;
 	int ret = 0;
 
@@ -2570,16 +2565,22 @@ int cpufreq_boost_trigger_state(int state)
 	cpufreq_driver->boost_enabled = state;
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-	ret = cpufreq_driver->set_boost(state);
-	if (ret) {
-		write_lock_irqsave(&cpufreq_driver_lock, flags);
-		cpufreq_driver->boost_enabled = !state;
-		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
-		pr_err("%s: Cannot %s BOOST\n",
-		       __func__, state ? "enable" : "disable");
+	for_each_active_policy(policy) {
+		ret = cpufreq_driver->set_boost(policy, state);
+		if (ret)
+			goto err_reset_state;
 	}
 
+	return 0;
+
+err_reset_state:
+	write_lock_irqsave(&cpufreq_driver_lock, flags);
+	cpufreq_driver->boost_enabled = !state;
+	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+	pr_err("%s: Cannot %s BOOST\n",
+	       __func__, state ? "enable" : "disable");
+
 	return ret;
 }
 
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 67d5950..3494f67 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -367,7 +367,7 @@ struct cpufreq_driver {
 
 	/* platform specific boost support code */
 	bool		boost_enabled;
-	int		(*set_boost)(int state);
+	int		(*set_boost)(struct cpufreq_policy *policy, int state);
 };
 
 /* flags */
-- 
1.7.12.4

[PATCH v4 2/2] CPPC: add support for SW BOOST

[Xiongfeng Wang]

To add SW BOOST support for CPPC, we need to get the max frequency of
boost mode and non-boost mode. ACPI spec 6.2 section 8.4.7.1 describe
the following two CPC registers.

"Highest performance is the absolute maximum performance an individual
processor may reach, assuming ideal conditions. This performance level
may not be sustainable for long durations, and may only be achievable if
other platform components are in a specific state; for example, it may
require other processors be in an idle state.

Nominal Performance is the maximum sustained performance level of the
processor, assuming ideal operating conditions. In absence of an
external constraint (power, thermal, etc.) this is the performance level
the platform is expected to be able to maintain continuously. All
processors are expected to be able to sustain their nominal performance
state simultaneously."

To add SW BOOST support for CPPC, we can use Highest Performance as the
max performance in boost mode and Nominal Performance as the max
performance in non-boost mode. If the Highest Performance is greater
than the Nominal Performance, we assume SW BOOST is supported.

The current CPPC driver does not support SW BOOST and use 'Highest
Performance' as the max performance the CPU can achieve. 'Nominal
Performance' is used to convert 'performance' to 'frequency'. That
means, if firmware enable boost and provide a value for Highest
Performance which is greater than Nominal Performance, boost feature is
enabled by default.

Because SW BOOST is disabled by default, so, after this patch, boost
feature is disabled by default even if boost is enabled by firmware.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/cppc_cpufreq.c | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index bda0b24..257d726 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -37,6 +37,7 @@
  * requested etc.
  */
 static struct cppc_cpudata **all_cpu_data;
+static bool boost_supported;
 
 struct cppc_workaround_oem_info {
 	char oem_id[ACPI_OEM_ID_SIZE + 1];
@@ -310,7 +311,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
 	 */
 	policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
-	policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
+	policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
 
 	/*
 	 * Set cpuinfo.min_freq to Lowest to make the full range of performance
@@ -318,7 +319,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	 * nonlinear perf
 	 */
 	policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
-	policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
+	policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
 
 	policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
 	policy->shared_type = cpu->shared_type;
@@ -343,6 +344,13 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 	cpu->cur_policy = policy;
 
+	/*
+	 * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
+	 * is supported.
+	 */
+	if (cpu->perf_caps.highest_perf > cpu->perf_caps.nominal_perf)
+		boost_supported = true;
+
 	/* Set policy->cur to max now. The governors will adjust later. */
 	policy->cur = cppc_cpufreq_perf_to_khz(cpu,
 					cpu->perf_caps.highest_perf);
@@ -410,6 +418,32 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
 	return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
 }
 
+static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
+{
+	struct cppc_cpudata *cpudata;
+	int ret;
+
+	if (!boost_supported) {
+		pr_err("BOOST not supported by CPU or firmware\n");
+		return -EINVAL;
+	}
+
+	cpudata = all_cpu_data[policy->cpu];
+	if (state)
+		policy->max = cppc_cpufreq_perf_to_khz(cpudata,
+					cpudata->perf_caps.highest_perf);
+	else
+		policy->max = cppc_cpufreq_perf_to_khz(cpudata,
+					cpudata->perf_caps.nominal_perf);
+	policy->cpuinfo.max_freq = policy->max;
+
+	ret = freq_qos_update_request(policy->max_freq_req, policy->max);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static struct cpufreq_driver cppc_cpufreq_driver = {
 	.flags = CPUFREQ_CONST_LOOPS,
 	.verify = cppc_verify_policy,
@@ -417,6 +451,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
 	.get = cppc_cpufreq_get_rate,
 	.init = cppc_cpufreq_cpu_init,
 	.stop_cpu = cppc_cpufreq_stop_cpu,
+	.set_boost = cppc_cpufreq_set_boost,
 	.name = "cppc_cpufreq",
 };
 
-- 
1.7.12.4

Re: [PATCH v4 0/2] add SW BOOST support for CPPC

[Viresh Kumar]

On 22-05-20, 11:34, Xiongfeng Wang wrote:
> ACPI spec 6.2 section 8.4.7.1 provide the following two CPC registers.
> 
> "Highest performance is the absolute maximum performance an individual
> processor may reach, assuming ideal conditions. This performance level
> may not be sustainable for long durations, and may only be achievable if
> other platform components are in a specific state; for example, it may
> require other processors be in an idle state.
> 
> Nominal Performance is the maximum sustained performance level of the
> processor, assuming ideal operating conditions. In absence of an
> external constraint (power, thermal, etc.) this is the performance level
> the platform is expected to be able to maintain continuously. All
> processors are expected to be able to sustain their nominal performance
> state simultaneously."
> 
> We can use Highest Performance as the max performance in boost mode and
> Nomial Performance as the max performance in non-boost mode. If the
> Highest Performance is greater than the Nominal Performance, we assume
> SW BOOST is supported.
> 
> v3->v4:
> 	run 'boost_set_msr_each' for each CPU in the policy rather than
> 	each CPU in the system for 'acpi-cpufreq'
> 	add 'Suggested-by'

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Re: [PATCH v4 1/2] cpufreq: change '.set_boost' to act on only one policy

[Rafael J. Wysocki]

On Friday, May 22, 2020 5:34:35 AM CEST Xiongfeng Wang wrote:
> Macro 'for_each_active_policy()' is defined internally. To avoid some
> cpufreq driver needing this macro to iterate over all the policies in
> '.set_boost' callback, we redefine '.set_boost' to act on only one
> policy and pass the policy as an argument.
> 'cpufreq_boost_trigger_state()' iterate over all the policies to set
> boost for the system. This is preparation for adding SW BOOST support
> for CPPC.
> 
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
> Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  drivers/cpufreq/acpi-cpufreq.c | 10 ++++----
>  drivers/cpufreq/cpufreq.c      | 53 +++++++++++++++++++++---------------------
>  include/linux/cpufreq.h        |  2 +-
>  3 files changed, 34 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 289e8ce..813aabf 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -126,12 +126,14 @@ static void boost_set_msr_each(void *p_en)
>  	boost_set_msr(enable);
>  }
>  
> -static int set_boost(int val)
> +static int set_boost(struct cpufreq_policy *policy, int val)
>  {
>  	get_online_cpus();
> -	on_each_cpu(boost_set_msr_each, (void *)(long)val, 1);
> +	on_each_cpu_mask(policy->cpus, boost_set_msr_each,
> +			 (void *)(long)val, 1);
>  	put_online_cpus();
> -	pr_debug("Core Boosting %sabled.\n", val ? "en" : "dis");
> +	pr_debug("CPU %*pbl: Core Boosting %sabled.\n",
> +		 cpumask_pr_args(policy->cpus), val ? "en" : "dis");
>  
>  	return 0;
>  }
> @@ -162,7 +164,7 @@ static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
>  	if (ret || val > 1)
>  		return -EINVAL;
>  
> -	set_boost(val);
> +	set_boost(policy, val);
>  
>  	return count;
>  }
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index d03f250..d0d86b1 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2532,34 +2532,29 @@ void cpufreq_update_limits(unsigned int cpu)
>  /*********************************************************************
>   *               BOOST						     *
>   *********************************************************************/
> -static int cpufreq_boost_set_sw(int state)
> +static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
>  {
> -	struct cpufreq_policy *policy;
> -
> -	for_each_active_policy(policy) {
> -		int ret;
> -
> -		if (!policy->freq_table)
> -			return -ENXIO;
> +	int ret;
>  
> -		ret = cpufreq_frequency_table_cpuinfo(policy,
> -						      policy->freq_table);
> -		if (ret) {
> -			pr_err("%s: Policy frequency update failed\n",
> -			       __func__);
> -			return ret;
> -		}
> +	if (!policy->freq_table)
> +		return -ENXIO;
>  
> -		ret = freq_qos_update_request(policy->max_freq_req, policy->max);
> -		if (ret < 0)
> -			return ret;
> +	ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
> +	if (ret) {
> +		pr_err("%s: Policy frequency update failed\n", __func__);
> +		return ret;
>  	}
>  
> +	ret = freq_qos_update_request(policy->max_freq_req, policy->max);
> +	if (ret < 0)
> +		return ret;
> +
>  	return 0;
>  }
>  
>  int cpufreq_boost_trigger_state(int state)
>  {
> +	struct cpufreq_policy *policy;
>  	unsigned long flags;
>  	int ret = 0;
>  
> @@ -2570,16 +2565,22 @@ int cpufreq_boost_trigger_state(int state)

AFAICS this gets called via sysfs without any cpufreq locking whatever, so
I'm not really sure what causes it to be safe with respect to CPU offline /
online, especially if the ->set_boost() callback only wants to do stuff
for CPUs that are online.

>  	cpufreq_driver->boost_enabled = state;
>  	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
>  
> -	ret = cpufreq_driver->set_boost(state);
> -	if (ret) {
> -		write_lock_irqsave(&cpufreq_driver_lock, flags);
> -		cpufreq_driver->boost_enabled = !state;
> -		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> -
> -		pr_err("%s: Cannot %s BOOST\n",
> -		       __func__, state ? "enable" : "disable");
> +	for_each_active_policy(policy) {
> +		ret = cpufreq_driver->set_boost(policy, state);
> +		if (ret)
> +			goto err_reset_state;
>  	}
>  
> +	return 0;
> +
> +err_reset_state:
> +	write_lock_irqsave(&cpufreq_driver_lock, flags);
> +	cpufreq_driver->boost_enabled = !state;
> +	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> +
> +	pr_err("%s: Cannot %s BOOST\n",
> +	       __func__, state ? "enable" : "disable");
> +
>  	return ret;
>  }
>  
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 67d5950..3494f67 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -367,7 +367,7 @@ struct cpufreq_driver {
>  
>  	/* platform specific boost support code */
>  	bool		boost_enabled;
> -	int		(*set_boost)(int state);
> +	int		(*set_boost)(struct cpufreq_policy *policy, int state);
>  };
>  
>  /* flags */
> 

Re: [PATCH v4 1/2] cpufreq: change '.set_boost' to act on only one policy

[Xiongfeng Wang]

Hi Rafael,

Thanks for your reply !

On 2020/5/28 20:48, Rafael J. Wysocki wrote:
> On Friday, May 22, 2020 5:34:35 AM CEST Xiongfeng Wang wrote:
>> Macro 'for_each_active_policy()' is defined internally. To avoid some
>> cpufreq driver needing this macro to iterate over all the policies in
>> '.set_boost' callback, we redefine '.set_boost' to act on only one
>> policy and pass the policy as an argument.
>> 'cpufreq_boost_trigger_state()' iterate over all the policies to set
>> boost for the system. This is preparation for adding SW BOOST support
>> for CPPC.
>>
>> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
>> Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
>> ---
>>  drivers/cpufreq/acpi-cpufreq.c | 10 ++++----
>>  drivers/cpufreq/cpufreq.c      | 53 +++++++++++++++++++++---------------------
>>  include/linux/cpufreq.h        |  2 +-
>>  3 files changed, 34 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
>> index 289e8ce..813aabf 100644
>> --- a/drivers/cpufreq/acpi-cpufreq.c
>> +++ b/drivers/cpufreq/acpi-cpufreq.c
>> @@ -126,12 +126,14 @@ static void boost_set_msr_each(void *p_en)
>>  	boost_set_msr(enable);
>>  }
>>  
>> -static int set_boost(int val)
>> +static int set_boost(struct cpufreq_policy *policy, int val)
>>  {
>>  	get_online_cpus();
>> -	on_each_cpu(boost_set_msr_each, (void *)(long)val, 1);
>> +	on_each_cpu_mask(policy->cpus, boost_set_msr_each,
>> +			 (void *)(long)val, 1);
>>  	put_online_cpus();
>> -	pr_debug("Core Boosting %sabled.\n", val ? "en" : "dis");
>> +	pr_debug("CPU %*pbl: Core Boosting %sabled.\n",
>> +		 cpumask_pr_args(policy->cpus), val ? "en" : "dis");
>>  
>>  	return 0;
>>  }
>> @@ -162,7 +164,7 @@ static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
>>  	if (ret || val > 1)
>>  		return -EINVAL;
>>  
>> -	set_boost(val);
>> +	set_boost(policy, val);
>>  
>>  	return count;
>>  }
>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>> index d03f250..d0d86b1 100644
>> --- a/drivers/cpufreq/cpufreq.c
>> +++ b/drivers/cpufreq/cpufreq.c
>> @@ -2532,34 +2532,29 @@ void cpufreq_update_limits(unsigned int cpu)
>>  /*********************************************************************
>>   *               BOOST						     *
>>   *********************************************************************/
>> -static int cpufreq_boost_set_sw(int state)
>> +static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
>>  {
>> -	struct cpufreq_policy *policy;
>> -
>> -	for_each_active_policy(policy) {
>> -		int ret;
>> -
>> -		if (!policy->freq_table)
>> -			return -ENXIO;
>> +	int ret;
>>  
>> -		ret = cpufreq_frequency_table_cpuinfo(policy,
>> -						      policy->freq_table);
>> -		if (ret) {
>> -			pr_err("%s: Policy frequency update failed\n",
>> -			       __func__);
>> -			return ret;
>> -		}
>> +	if (!policy->freq_table)
>> +		return -ENXIO;
>>  
>> -		ret = freq_qos_update_request(policy->max_freq_req, policy->max);
>> -		if (ret < 0)
>> -			return ret;
>> +	ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
>> +	if (ret) {
>> +		pr_err("%s: Policy frequency update failed\n", __func__);
>> +		return ret;
>>  	}
>>  
>> +	ret = freq_qos_update_request(policy->max_freq_req, policy->max);
>> +	if (ret < 0)
>> +		return ret;
>> +
>>  	return 0;
>>  }
>>  
>>  int cpufreq_boost_trigger_state(int state)
>>  {
>> +	struct cpufreq_policy *policy;
>>  	unsigned long flags;
>>  	int ret = 0;
>>  
>> @@ -2570,16 +2565,22 @@ int cpufreq_boost_trigger_state(int state)
> 
> AFAICS this gets called via sysfs without any cpufreq locking whatever, so
> I'm not really sure what causes it to be safe with respect to CPU offline /
> online, especially if the ->set_boost() callback only wants to do stuff
> for CPUs that are online.

Thanks for your advice. Yes, we have 'cpu_hotplug_lock' in 'set_boost' in
acpi_cpufreq. But we don't have 'cpu_hotplug_lock' for the general SW BOOST
framework. So I think I will need to move the lock from 'set_boost()' to
'store_cpb()' and add lock in 'cpufreq_boost_trigger_state' for the general SW
BOOST.

Thanks,
Xiongfeng

> 
>>  	cpufreq_driver->boost_enabled = state;
>>  	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
>>  
>> -	ret = cpufreq_driver->set_boost(state);
>> -	if (ret) {
>> -		write_lock_irqsave(&cpufreq_driver_lock, flags);
>> -		cpufreq_driver->boost_enabled = !state;
>> -		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
>> -
>> -		pr_err("%s: Cannot %s BOOST\n",
>> -		       __func__, state ? "enable" : "disable");
>> +	for_each_active_policy(policy) {
>> +		ret = cpufreq_driver->set_boost(policy, state);
>> +		if (ret)
>> +			goto err_reset_state;
>>  	}
>>  
>> +	return 0;
>> +
>> +err_reset_state:
>> +	write_lock_irqsave(&cpufreq_driver_lock, flags);
>> +	cpufreq_driver->boost_enabled = !state;
>> +	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
>> +
>> +	pr_err("%s: Cannot %s BOOST\n",
>> +	       __func__, state ? "enable" : "disable");
>> +
>>  	return ret;
>>  }
>>  
>> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
>> index 67d5950..3494f67 100644
>> --- a/include/linux/cpufreq.h
>> +++ b/include/linux/cpufreq.h
>> @@ -367,7 +367,7 @@ struct cpufreq_driver {
>>  
>>  	/* platform specific boost support code */
>>  	bool		boost_enabled;
>> -	int		(*set_boost)(int state);
>> +	int		(*set_boost)(struct cpufreq_policy *policy, int state);
>>  };
>>  
>>  /* flags */
>>
> 
> 
> 
> 
> 
> .
>