From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Saravana Kannan <skannan@codeaurora.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux PM list <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Juri Lelli <juri.lelli@arm.com>,
Steve Muckle <steve.muckle@linaro.org>
Subject: Re: [PATCH 3/11] cpufreq: governor: Use common global_dbs_data pointer
Date: Thu, 4 Feb 2016 02:25:17 +0100 [thread overview]
Message-ID: <CAJZ5v0gdR23cCocT3qw4ry26bMQ=qjcwatk9uu-Z1JDLKTSffQ@mail.gmail.com> (raw)
In-Reply-To: <56B2A53C.8080503@codeaurora.org>
On Thu, Feb 4, 2016 at 2:11 AM, Saravana Kannan <skannan@codeaurora.org> wrote:
> On 02/03/2016 03:22 PM, Rafael J. Wysocki wrote:
>>
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> If the ondemand and conservative governors cannot use per-policy
>> tunables (CPUFREQ_HAVE_GOVERNOR_PER_POLICY is not set in the cpufreq
>> driver), all policy objects point to the same single dbs_data object.
>> Additionally, that object is pointed to by a global pointer hidden in
>> the governor's data structures.
>>
>> There is no reason for that pointer to be buried in those
>> data structures, though, so make it explicitly global.
>>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> ---
>> drivers/cpufreq/cpufreq_governor.c | 20 ++++++++++----------
>> drivers/cpufreq/cpufreq_governor.h | 20 ++++++++++----------
>> 2 files changed, 20 insertions(+), 20 deletions(-)
>>
>> Index: linux-pm/drivers/cpufreq/cpufreq_governor.h
>> ===================================================================
>> --- linux-pm.orig/drivers/cpufreq/cpufreq_governor.h
>> +++ linux-pm/drivers/cpufreq/cpufreq_governor.h
>> @@ -78,7 +78,7 @@ __ATTR(_name, 0644, show_##_name##_gov_p
>> static ssize_t show_##file_name##_gov_sys \
>> (struct kobject *kobj, struct attribute *attr, char *buf) \
>> { \
>> - struct _gov##_dbs_tuners *tuners =
>> _gov##_dbs_cdata.gdbs_data->tuners; \
>> + struct _gov##_dbs_tuners *tuners = global_dbs_data->tuners; \
>> return sprintf(buf, "%u\n", tuners->file_name); \
>> } \
>> \
>> @@ -94,7 +94,7 @@ static ssize_t show_##file_name##_gov_po
>> static ssize_t store_##file_name##_gov_sys \
>> (struct kobject *kobj, struct attribute *attr, const char *buf, size_t
>> count) \
>> { \
>> - struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data; \
>> + struct dbs_data *dbs_data = global_dbs_data; \
>> return store_##file_name(dbs_data, buf, count); \
>> } \
>> \
>> @@ -201,19 +201,14 @@ struct cs_dbs_tuners {
>> /* Common Governor data across policies */
>> struct dbs_data;
>> struct common_dbs_data {
>> - /* Common across governors */
>> + struct cpufreq_governor gov;
>> +
>> #define GOV_ONDEMAND 0
>> #define GOV_CONSERVATIVE 1
>> int governor;
>> struct attribute_group *attr_group_gov_sys; /* one governor -
>> system */
>> struct attribute_group *attr_group_gov_pol; /* one governor -
>> policy */
>>
>> - /*
>> - * Common data for platforms that don't set
>> - * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
>> - */
>> - struct dbs_data *gdbs_data;
>> -
>> struct cpu_dbs_info *(*get_cpu_cdbs)(int cpu);
>> void *(*get_cpu_dbs_info_s)(int cpu);
>> unsigned int (*gov_dbs_timer)(struct cpufreq_policy *policy);
>> @@ -233,6 +228,11 @@ struct dbs_data {
>> void *tuners;
>> };
>>
>> +/*
>> + * Common governor data for platforms without
>> CPUFREQ_HAVE_GOVERNOR_PER_POLICY.
>> + */
>> +extern struct dbs_data *global_dbs_data;
>> +
>> /* Governor specific ops, will be passed to dbs_data->gov_ops */
>> struct od_ops {
>> void (*powersave_bias_init_cpu)(int cpu);
>> @@ -256,7 +256,7 @@ static inline int delay_for_sampling_rat
>> static ssize_t show_sampling_rate_min_gov_sys \
>> (struct kobject *kobj, struct attribute *attr, char *buf) \
>> { \
>> - struct dbs_data *dbs_data = _gov##_dbs_cdata.gdbs_data; \
>> + struct dbs_data *dbs_data = global_dbs_data; \
>> return sprintf(buf, "%u\n", dbs_data->min_sampling_rate); \
>> } \
>> \
>> Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
>> ===================================================================
>> --- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
>> +++ linux-pm/drivers/cpufreq/cpufreq_governor.c
>> @@ -22,6 +22,9 @@
>>
>> #include "cpufreq_governor.h"
>>
>> +struct dbs_data *global_dbs_data;
>> +EXPORT_SYMBOL_GPL(global_dbs_data);
>> +
>> DEFINE_MUTEX(dbs_data_mutex);
>> EXPORT_SYMBOL_GPL(dbs_data_mutex);
>>
>> @@ -377,22 +380,19 @@ static int cpufreq_governor_init(struct
>> latency * LATENCY_MULTIPLIER));
>>
>> if (!have_governor_per_policy())
>> - cdata->gdbs_data = dbs_data;
>> + global_dbs_data = dbs_data;
>>
>> policy->governor_data = dbs_data;
>>
>> ret = sysfs_create_group(get_governor_parent_kobj(policy),
>> get_sysfs_attr(dbs_data));
>> - if (ret)
>> - goto reset_gdbs_data;
>> -
>> - return 0;
>> + if (!ret)
>> + return 0;
>
>
> I think the previous method of a handling the error is easier to read and
> more in line with the typical kernel coding style. The successful path ends
> in an unconditional return statement and the error paths are handled with a
> goto.
You are talking about something like this now:
if (condition)
goto label;
return 0;
label:
do stuff
I'm sorry, but I fail to see how this is easier to read than
if (!condition)
return 0;
do stuff
The return statement is not unconditional in either case, but in the
first one it is just obfuscated by using the label and goto which are
completely unnecessary.
>
> This also doesn't seem relevant to what the patch is trying to do. So, I'd
> prefer that it be left as is.
>
This is a fair point, though. I can make that change later. :-)
Thanks,
Rafael
next prev parent reply other threads:[~2016-02-04 1:25 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 23:12 [PATCH 0/11] cpufreq: governor: ondemand/conservative data structures rework Rafael J. Wysocki
2016-02-03 23:14 ` [PATCH 1/11] cpufreq: Clean up default and fallback governor setup Rafael J. Wysocki
2016-02-04 0:55 ` Saravana Kannan
2016-02-04 5:03 ` Viresh Kumar
2016-02-03 23:16 ` [PATCH 2/11] cpufreq: governor: Use common mutex for dbs_data protection Rafael J. Wysocki
2016-02-04 0:59 ` Saravana Kannan
2016-02-04 5:09 ` Viresh Kumar
2016-02-04 16:46 ` Rafael J. Wysocki
2016-02-05 2:59 ` Viresh Kumar
2016-02-05 3:06 ` Rafael J. Wysocki
2016-02-05 3:15 ` Rafael J. Wysocki
2016-02-05 3:17 ` Rafael J. Wysocki
2016-02-05 3:24 ` Viresh Kumar
2016-02-05 3:33 ` Rafael J. Wysocki
2016-02-05 3:22 ` Viresh Kumar
2016-02-03 23:22 ` [PATCH 3/11] cpufreq: governor: Use common global_dbs_data pointer Rafael J. Wysocki
2016-02-04 1:11 ` Saravana Kannan
2016-02-04 1:25 ` Rafael J. Wysocki [this message]
2016-02-04 1:40 ` Saravana Kannan
2016-02-04 5:38 ` Viresh Kumar
2016-02-04 1:47 ` Saravana Kannan
2016-02-04 5:36 ` Viresh Kumar
[not found] ` <CAHZ_5WxJSDtFyFdCc-D2=HSaPON=3rzUxpxPYsCyZvrV1Nv3qw@mail.gmail.com>
2016-02-04 8:25 ` Viresh Kumar
2016-02-04 11:31 ` Gautham R Shenoy
2016-02-04 11:35 ` Viresh Kumar
2016-02-04 16:52 ` Rafael J. Wysocki
2016-02-05 3:02 ` Viresh Kumar
2016-02-05 3:10 ` Rafael J. Wysocki
2016-02-03 23:29 ` [PATCH 4/11] cpufreq: governor: Avoid passing dbs_data pointers around unnecessarily Rafael J. Wysocki
2016-02-04 1:37 ` Saravana Kannan
2016-02-03 23:31 ` [PATCH 5/11] cpufreq: governor: Put governor structure into common_dbs_data Rafael J. Wysocki
2016-02-04 1:57 ` Saravana Kannan
2016-02-03 23:32 ` [PATCH 6/11] cpufreq: governor: Rename some data types and variables Rafael J. Wysocki
2016-02-03 23:33 ` [PATCH 7/11] cpufreq: governor: Rework cpufreq_governor_dbs() Rafael J. Wysocki
2016-02-04 2:03 ` Saravana Kannan
2016-02-03 23:35 ` [PATCH 8/11] cpufreq: governor: Drop the gov pointer from struct dbs_data Rafael J. Wysocki
2016-02-03 23:35 ` [PATCH 9/11] cpufreq: governor: Rename cpu_common_dbs_info to policy_dbs_info Rafael J. Wysocki
2016-02-03 23:37 ` [PATCH 10/11] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-03 23:38 ` [PATCH 11/11] cpufreq: governor: Drop cpu argument from dbs_check_cpu() Rafael J. Wysocki
2016-02-04 5:40 ` [PATCH 0/11] cpufreq: governor: ondemand/conservative data structures rework Viresh Kumar
2016-02-04 17:22 ` Rafael J. Wysocki
2016-02-05 2:07 ` [PATCH v2 0/10] " Rafael J. Wysocki
2016-02-05 2:11 ` [PATCH v2 1/10] cpufreq: Clean up default and fallback governor setup Rafael J. Wysocki
2016-02-10 5:15 ` Gautham R Shenoy
2016-02-10 5:48 ` Gautham R Shenoy
2016-02-05 2:14 ` [PATCH v2 2/10] cpufreq: governor: Use common mutex for dbs_data protection Rafael J. Wysocki
2016-02-05 6:53 ` Viresh Kumar
2016-02-05 22:59 ` Rafael J. Wysocki
2016-02-07 9:31 ` Viresh Kumar
2016-02-07 14:33 ` Rafael J. Wysocki
2016-02-05 2:15 ` [PATCH v2 3/10] cpufreq: governor: Avoid passing dbs_data pointers around unnecessarily Rafael J. Wysocki
2016-02-05 7:09 ` Viresh Kumar
2016-02-05 2:16 ` [PATCH v2 4/10] cpufreq: governor: Put governor structure into common_dbs_data Rafael J. Wysocki
2016-02-05 7:13 ` Viresh Kumar
2016-02-05 2:17 ` [PATCH v2 5/10] cpufreq: governor: Rename some data types and variables Rafael J. Wysocki
2016-02-05 7:17 ` Viresh Kumar
2016-02-05 2:18 ` [PATCH v2 6/10] cpufreq: governor: Rework cpufreq_governor_dbs() Rafael J. Wysocki
2016-02-05 8:14 ` Viresh Kumar
2016-02-05 2:19 ` [PATCH v2 7/10] cpufreq: governor: Drop the gov pointer from struct dbs_data Rafael J. Wysocki
2016-02-05 8:28 ` Viresh Kumar
2016-02-05 2:20 ` [PATCH v2 8/10] cpufreq: governor: Rename cpu_common_dbs_info to policy_dbs_info Rafael J. Wysocki
2016-02-05 8:34 ` Viresh Kumar
2016-02-05 22:50 ` Rafael J. Wysocki
2016-02-06 12:48 ` [PATCH v3 " Rafael J. Wysocki
2016-02-07 9:31 ` Viresh Kumar
2016-02-05 2:21 ` [PATCH v2 9/10] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-05 9:13 ` Viresh Kumar
2016-02-05 22:47 ` Rafael J. Wysocki
2016-02-07 9:29 ` Viresh Kumar
2016-02-07 14:34 ` Rafael J. Wysocki
2016-02-05 2:21 ` [PATCH v2 10/10] cpufreq: governor: Drop cpu argument from dbs_check_cpu() Rafael J. Wysocki
2016-02-05 9:15 ` Viresh Kumar
2016-02-06 12:50 ` [PATCH v3 " Rafael J. Wysocki
2016-02-07 9:32 ` Viresh Kumar
2016-02-06 12:44 ` [PATCH v2 0/10] cpufreq: governor: ondemand/conservative data structures rework Rafael J. Wysocki
2016-02-07 15:22 ` [PATCH 0/3] cpufreq: governor: Data structure rearrangement Rafael J. Wysocki
2016-02-07 15:23 ` [PATCH 1/3] cpufreq: governor: Simplify cpufreq_governor_limits() Rafael J. Wysocki
2016-02-07 15:40 ` Viresh Kumar
2016-02-08 0:59 ` Rafael J. Wysocki
2016-02-07 15:24 ` [PATCH 2/3] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-07 15:45 ` Viresh Kumar
2016-02-07 15:54 ` Viresh Kumar
2016-02-07 15:55 ` Viresh Kumar
2016-02-07 15:25 ` [PATCH 3/3] cpufreq: governor: Symmetrize cpu_dbs_info initialization and cleanup Rafael J. Wysocki
2016-02-07 15:52 ` Viresh Kumar
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