| Message ID | 91abed4ff8fe68f26fe0bdc840982bb972dba6dc.1437999691.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Monday, July 27, 2015 05:58:07 PM Viresh Kumar wrote: > Conservative governor has its own 'enable' field to check if > conservative governor is used for a CPU or not > > This can be checked by policy->governor with 'cpufreq_gov_conservative' > and so this field can be dropped. > > Because its not guaranteed that dbs_info->cdbs.shared will a valid > pointer for all CPUs (will be NULL for CPUs that don't use > ondemand/conservative governors), we can't use it anymore. Lets get > policy with cpufreq_cpu_get() instead. But previously, if the enable bit was set, we actually new that the pointer was valid, right? > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/cpufreq_conservative.c | 34 +++++++++++++++++++++------------- > drivers/cpufreq/cpufreq_governor.c | 12 +----------- > drivers/cpufreq/cpufreq_governor.h | 1 - > 3 files changed, 22 insertions(+), 25 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c > index 84a1506950a7..18bfbc313e48 100644 > --- a/drivers/cpufreq/cpufreq_conservative.c > +++ b/drivers/cpufreq/cpufreq_conservative.c > @@ -23,6 +23,19 @@ > > static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); > > +static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, > + unsigned int event); > + > +#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE > +static > +#endif > +struct cpufreq_governor cpufreq_gov_conservative = { > + .name = "conservative", > + .governor = cs_cpufreq_governor_dbs, > + .max_transition_latency = TRANSITION_LATENCY_LIMIT, > + .owner = THIS_MODULE, > +}; > + > static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, > struct cpufreq_policy *policy) > { > @@ -119,12 +132,14 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, > struct cpufreq_freqs *freq = data; > struct cs_cpu_dbs_info_s *dbs_info = > &per_cpu(cs_cpu_dbs_info, freq->cpu); > - struct cpufreq_policy *policy; > + struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu); > > - if (!dbs_info->enable) > + if (!policy) > return 0; > > - policy = dbs_info->cdbs.shared->policy; So here we could get to the policy directly. After the change we have to: - acquire cpufreq_rwsem - acquire cpufreq_driver_lock - go the kobject_get on policy->kobj and then finally drop the reference to the kobject when we're done. So may I ask where exactly is the improvement? > + /* policy isn't governed by conservative governor */ > + if (policy->governor != &cpufreq_gov_conservative) > + goto policy_put; > > /* > * we only care if our internally tracked freq moves outside the 'valid' Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08-09-15, 02:17, Rafael J. Wysocki wrote: > > static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, > > struct cpufreq_policy *policy) > > { > > @@ -119,12 +132,14 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, > > struct cpufreq_freqs *freq = data; > > struct cs_cpu_dbs_info_s *dbs_info = > > &per_cpu(cs_cpu_dbs_info, freq->cpu); > > - struct cpufreq_policy *policy; > > + struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu); > > > > - if (!dbs_info->enable) > > + if (!policy) > > return 0; > > > > - policy = dbs_info->cdbs.shared->policy; > > So here we could get to the policy directly. After the change we have to: > > - acquire cpufreq_rwsem > - acquire cpufreq_driver_lock > - go the kobject_get on policy->kobj Hmm, actually we can do cpufreq_cpu_get_raw() here as this is getting called from notifier and policy isn't going to get freed for sure. And then it wouldn't be that bad. > and then finally drop the reference to the kobject when we're done. > > So may I ask where exactly is the improvement? Agree. Let me resend it quickly. > > + /* policy isn't governed by conservative governor */ > > + if (policy->governor != &cpufreq_gov_conservative) > > + goto policy_put; > > > > /* > > * we only care if our internally tracked freq moves outside the 'valid' > > Thanks, > Rafael
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index 84a1506950a7..18bfbc313e48 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -23,6 +23,19 @@ static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); +static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, + unsigned int event); + +#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE +static +#endif +struct cpufreq_governor cpufreq_gov_conservative = { + .name = "conservative", + .governor = cs_cpufreq_governor_dbs, + .max_transition_latency = TRANSITION_LATENCY_LIMIT, + .owner = THIS_MODULE, +}; + static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, struct cpufreq_policy *policy) { @@ -119,12 +132,14 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, struct cpufreq_freqs *freq = data; struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, freq->cpu); - struct cpufreq_policy *policy; + struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu); - if (!dbs_info->enable) + if (!policy) return 0; - policy = dbs_info->cdbs.shared->policy; + /* policy isn't governed by conservative governor */ + if (policy->governor != &cpufreq_gov_conservative) + goto policy_put; /* * we only care if our internally tracked freq moves outside the 'valid' @@ -134,6 +149,9 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, || dbs_info->requested_freq < policy->min) dbs_info->requested_freq = freq->new; +policy_put: + cpufreq_cpu_put(policy); + return 0; } @@ -367,16 +385,6 @@ static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event); } -#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE -static -#endif -struct cpufreq_governor cpufreq_gov_conservative = { - .name = "conservative", - .governor = cs_cpufreq_governor_dbs, - .max_transition_latency = TRANSITION_LATENCY_LIMIT, - .owner = THIS_MODULE, -}; - static int __init cpufreq_gov_dbs_init(void) { return cpufreq_register_governor(&cpufreq_gov_conservative); diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 939197ffa4ac..750626d8fb03 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -463,7 +463,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy, cdata->get_cpu_dbs_info_s(cpu); cs_dbs_info->down_skip = 0; - cs_dbs_info->enable = 1; cs_dbs_info->requested_freq = policy->cur; } else { struct od_ops *od_ops = cdata->gov_ops; @@ -482,9 +481,7 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy, static int cpufreq_governor_stop(struct cpufreq_policy *policy, struct dbs_data *dbs_data) { - struct common_dbs_data *cdata = dbs_data->cdata; - unsigned int cpu = policy->cpu; - struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu); + struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(policy->cpu); struct cpu_common_dbs_info *shared = cdbs->shared; /* State should be equivalent to START */ @@ -493,13 +490,6 @@ static int cpufreq_governor_stop(struct cpufreq_policy *policy, gov_cancel_work(dbs_data, policy); - if (cdata->governor == GOV_CONSERVATIVE) { - struct cs_cpu_dbs_info_s *cs_dbs_info = - cdata->get_cpu_dbs_info_s(cpu); - - cs_dbs_info->enable = 0; - } - shared->policy = NULL; mutex_destroy(&shared->timer_mutex); return 0; diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h index 50f171796632..5621bb03e874 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -170,7 +170,6 @@ struct cs_cpu_dbs_info_s { struct cpu_dbs_info cdbs; unsigned int down_skip; unsigned int requested_freq; - unsigned int enable:1; }; /* Per policy Governors sysfs tunables */
Conservative governor has its own 'enable' field to check if conservative governor is used for a CPU or not This can be checked by policy->governor with 'cpufreq_gov_conservative' and so this field can be dropped. Because its not guaranteed that dbs_info->cdbs.shared will a valid pointer for all CPUs (will be NULL for CPUs that don't use ondemand/conservative governors), we can't use it anymore. Lets get policy with cpufreq_cpu_get() instead. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq_conservative.c | 34 +++++++++++++++++++++------------- drivers/cpufreq/cpufreq_governor.c | 12 +----------- drivers/cpufreq/cpufreq_governor.h | 1 - 3 files changed, 22 insertions(+), 25 deletions(-)