Re: [PATCH 12/12] cpufreq: conservative: remove 'enable' field

On 06/11/2015 04:21 PM, Viresh Kumar wrote:

Conservative governor has its own 'enable' field to check in notifier if notification is required or not. The same functionality can now be achieved with 'ccdbs->enabled instead'. Lets get rid of 'enable'.

Since this is a policy wide value, is there a race possible between switching to a new governor and checking of this value in the notifier ? We don't want scenarios where we have switched from conservative to ondemand and ccdbs->enabled = 1 while a parallel notifier thread is running and thinks the conservative governor is enabled.

Regards Preeti U Murthy

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org

drivers/cpufreq/cpufreq_conservative.c | 12 ++++++------ drivers/cpufreq/cpufreq_governor.c | 13 +------------ drivers/cpufreq/cpufreq_governor.h | 1 - 3 files changed, 7 insertions(+), 19 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index 0e4154e584bf..e0b49729307d 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -21,6 +21,7 @@ #define DEF_SAMPLING_DOWN_FACTOR (1) #define MAX_SAMPLING_DOWN_FACTOR (10)

+static struct common_dbs_data cs_dbs_cdata; static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);

static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, @@ -119,13 +120,13 @@ 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 cpu_common_dbs_info *ccdbs = dbs_info->cdbs.ccdbs;
• struct cpufreq_policy *policy = ccdbs->policy;

• if (!dbs_info->enable)

• mutex_lock(&cs_dbs_cdata.mutex);
• if (!ccdbs->enabled) return 0;

• policy = dbs_info->cdbs.ccdbs->policy;
• /*
  • we only care if our internally tracked freq moves outside the 'valid'
  • ranges of frequency available to us otherwise we do not change it

@@ -133,6 +134,7 @@ static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, if (dbs_info->requested_freq > policy->max || dbs_info->requested_freq < policy->min) dbs_info->requested_freq = freq->new;

• mutex_unlock(&cs_dbs_cdata.mutex);

  return 0;

} @@ -142,8 +144,6 @@ static struct notifier_block cs_cpufreq_notifier_block = { };

/************************** sysfs interface ************************/ -static struct common_dbs_data cs_dbs_cdata;

static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, const char *buf, size_t count) { diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index c26f535d3d91..7f348c3a4782 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -465,7 +465,6 @@ 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;

@@ -485,9 +484,7 @@ 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 *ccdbs = cdbs->ccdbs;

  /* Shouldn't be already stopped */

@@ -496,14 +493,6 @@ static int cpufreq_governor_stop(struct cpufreq_policy *policy,

ccdbs->enabled = false; 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;
  

• }
• return 0;

}

diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h index 7da5aedb8174..7f651bdf43ae 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -165,7 +165,6 @@ 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 */