Re: [PATCH v2 16/16] cpufreq/amd-pstate: Drop boost_state variable

["Gautham R. Shenoy" <gautham.shenoy@amd.com>]

Hello Mario,

On Sun, Dec 08, 2024 at 12:30:31AM -0600, Mario Limonciello wrote:
> Currently boost_state is cached for every processor in cpudata structure
> and driver boost state is set for every processor.
> 
> Both of these aren't necessary as the driver only needs to set once and
> the policy stores whether boost is enabled.
> 
> Move the driver boost setting to registration and adjust all references
> to cached value to pull from the policy instead.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Thanks for cleaning this up.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

--
Thanks and Regards
gautham.

> ---
>  drivers/cpufreq/amd-pstate.c | 26 +++++++++++++-------------
>  drivers/cpufreq/amd-pstate.h |  1 -
>  2 files changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index a4ededb8d89df..3f6208828c063 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -315,9 +315,10 @@ static int shmem_set_epp(struct amd_cpudata *cpudata, u32 epp)
>  	return ret;
>  }
>  
> -static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
> -		int pref_index)
> +static int amd_pstate_set_energy_pref_index(struct cpufreq_policy *policy,
> +					    int pref_index)
>  {
> +	struct amd_cpudata *cpudata = policy->driver_data;
>  	int epp;
>  
>  	if (!pref_index)
> @@ -335,7 +336,7 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
>  					  epp,
>  					  FIELD_GET(AMD_CPPC_MIN_PERF_MASK, cpudata->cppc_req_cached),
>  					  FIELD_GET(AMD_CPPC_MAX_PERF_MASK, cpudata->cppc_req_cached),
> -					  cpudata->boost_state);
> +					  policy->boost_enabled);
>  	}
>  
>  	return amd_pstate_set_epp(cpudata, epp);
> @@ -746,7 +747,6 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
>  	guard(mutex)(&amd_pstate_driver_lock);
>  
>  	ret = amd_pstate_cpu_boost_update(policy, state);
> -	WRITE_ONCE(cpudata->boost_state, !ret ? state : false);
>  	policy->boost_enabled = !ret ? state : false;
>  	refresh_frequency_limits(policy);
>  
> @@ -768,9 +768,6 @@ static int amd_pstate_init_boost_support(struct amd_cpudata *cpudata)
>  		goto exit_err;
>  	}
>  
> -	/* at least one CPU supports CPB, even if others fail later on to set up */
> -	current_pstate_driver->boost_enabled = true;
> -
>  	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
>  	if (ret) {
>  		pr_err_once("failed to read initial CPU boost state!\n");
> @@ -1176,7 +1173,6 @@ static ssize_t show_energy_performance_available_preferences(
>  static ssize_t store_energy_performance_preference(
>  		struct cpufreq_policy *policy, const char *buf, size_t count)
>  {
> -	struct amd_cpudata *cpudata = policy->driver_data;
>  	char str_preference[21];
>  	ssize_t ret;
>  
> @@ -1190,7 +1186,7 @@ static ssize_t store_energy_performance_preference(
>  
>  	guard(mutex)(&amd_pstate_limits_lock);
>  
> -	ret = amd_pstate_set_energy_pref_index(cpudata, ret);
> +	ret = amd_pstate_set_energy_pref_index(policy, ret);
>  
>  	return ret ? ret : count;
>  }
> @@ -1265,6 +1261,9 @@ static int amd_pstate_register_driver(int mode)
>  		return ret;
>  	}
>  
> +	/* at least one CPU supports CPB */
> +	current_pstate_driver->boost_enabled = cpu_feature_enabled(X86_FEATURE_CPB);
> +
>  	ret = cpufreq_register_driver(current_pstate_driver);
>  	if (ret) {
>  		amd_pstate_driver_cleanup();
> @@ -1604,8 +1603,9 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
>  	return 0;
>  }
>  
> -static int amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
> +static int amd_pstate_epp_reenable(struct cpufreq_policy *policy)
>  {
> +	struct amd_cpudata *cpudata = policy->driver_data;
>  	u64 max_perf;
>  	int ret;
>  
> @@ -1619,7 +1619,7 @@ static int amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
>  		trace_amd_pstate_epp_perf(cpudata->cpu, cpudata->highest_perf,
>  					  cpudata->epp_cached,
>  					  FIELD_GET(AMD_CPPC_MIN_PERF_MASK, cpudata->cppc_req_cached),
> -					  max_perf, cpudata->boost_state);
> +					  max_perf, policy->boost_enabled);
>  	}
>  
>  	return amd_pstate_update_perf(cpudata, 0, 0, max_perf, cpudata->epp_cached, false);
> @@ -1632,7 +1632,7 @@ static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
>  
>  	pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
>  
> -	ret = amd_pstate_epp_reenable(cpudata);
> +	ret = amd_pstate_epp_reenable(policy);
>  	if (ret)
>  		return ret;
>  	cpudata->suspended = false;
> @@ -1690,7 +1690,7 @@ static int amd_pstate_epp_resume(struct cpufreq_policy *policy)
>  		guard(mutex)(&amd_pstate_limits_lock);
>  
>  		/* enable amd pstate from suspend state*/
> -		amd_pstate_epp_reenable(cpudata);
> +		amd_pstate_epp_reenable(policy);
>  
>  		cpudata->suspended = false;
>  	}
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index 7765c82f975c6..9747e3be6ceee 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -98,7 +98,6 @@ struct amd_cpudata {
>  	u64	cppc_cap1_cached;
>  	bool	suspended;
>  	s16	epp_default;
> -	bool	boost_state;
>  };
>  
>  /*
> -- 
> 2.43.0
>