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* Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
  2020-01-14  1:45 ` [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file Chanwoo Choi
@ 2020-01-14  1:45   ` Dmitry Osipenko
  2020-01-14  2:23     ` Chanwoo Choi
  0 siblings, 1 reply; 7+ messages in thread
From: Dmitry Osipenko @ 2020-01-14  1:45 UTC (permalink / raw)
  To: Chanwoo Choi, linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, bjorn.andersson, jcrouse, chanwoo,
	myungjoo.ham, kyungmin.park

14.01.2020 04:45, Chanwoo Choi пишет:
> Add debugfs interface to provide debugging information of devfreq device.
> It contains 'devfreq_summary' entry to show the summary of registered
> devfreq devices as following and the additional debugfs file will be added.
> - /sys/kernel/debug/devfreq/devfreq_summary
> 
> [Detailed description of each field of 'devfreq_summary' debugfs file]
> - dev_name	: Device name of h/w.
> - dev		: Device name made by devfreq core.
> - parent_dev	: If devfreq device uses the passive governor,
> 		  show parent devfreq device name. Otherwise, show 'null'.
> - governor	: Devfreq governor.
> - polling_ms	: If devfreq device uses the simple_ondemand governor,
> 		  polling_ms is necessary for the period. (unit: millisecond)
> - cur_freq_Hz	: Current Frequency (unit: Hz)
> - old_freq_Hz	: Frequency before changing. (unit: Hz)
> - new_freq_Hz	: Frequency after changed. (unit: Hz)
> 
> [For example on Exynos5422-based Odroid-XU3 board]
> $ cat /sys/kernel/debug/devfreq/devfreq_summary
> dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
> ------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
> 10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
> soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
> soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
> soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
> soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
> soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
> soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
> soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
> soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
> soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
> soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
> soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
> soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
> soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
> soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
> soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
> soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000
> 
> [lkp: Reported the build error]
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Changes from v2:
> - Show 'null' at 'parent_dev' field when governor of devfreq device
>   is not passive
> Changes from v1:
> - Drop the patch about 'devfreq_transitions' debugfs file
> - Modify from 'hz' to 'Hz'
> - Edit the indentation of 'devfreq_summary' when show summary
> - Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir
> 
>  drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 84 insertions(+)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 89260b17598f..c5ef2d194b1b 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -10,6 +10,7 @@
>  #include <linux/kernel.h>
>  #include <linux/kmod.h>
>  #include <linux/sched.h>
> +#include <linux/debugfs.h>
>  #include <linux/errno.h>
>  #include <linux/err.h>
>  #include <linux/init.h>
> @@ -33,6 +34,7 @@
>  #define HZ_PER_KHZ	1000
>  
>  static struct class *devfreq_class;
> +static struct dentry *devfreq_debugfs;
>  
>  /*
>   * devfreq core provides delayed work based load monitoring helper
> @@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
>  };
>  ATTRIBUTE_GROUPS(devfreq);
>  
> +/**
> + * devfreq_summary_show() - Show the summary of the devfreq devices
> + * @s:		seq_file instance to show the summary of devfreq devices
> + * @data:	not used
> + *
> + * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
> + * It helps that user can know the detailed information of the devfreq devices.
> + *
> + * Return 0 always because it shows the information without any data change.
> + */
> +static int devfreq_summary_show(struct seq_file *s, void *data)
> +{
> +	struct devfreq *devfreq;
> +	struct devfreq *p_devfreq = NULL;
> +	unsigned long cur_freq, min_freq, max_freq;
> +	unsigned int polling_ms;
> +
> +	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
> +			"dev_name",
> +			"dev",
> +			"parent_dev",
> +			"governor",
> +			"polling_ms",
> +			"cur_freq_Hz",
> +			"min_freq_Hz",
> +			"max_freq_Hz");
> +	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
> +			"------------------------------",
> +			"----------",
> +			"----------",
> +			"---------------",
> +			"----------",
> +			"------------",
> +			"------------",
> +			"------------");
> +
> +	mutex_lock(&devfreq_list_lock);
> +
> +	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
> +		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
> +							DEVFREQ_NAME_LEN)) {
> +			struct devfreq_passive_data *data = devfreq->data;
> +
> +			if (data)
> +				p_devfreq = data->parent;
> +		} else {
> +			p_devfreq = NULL;
> +		}
> +
> +		mutex_lock(&devfreq->lock);
> +		cur_freq = devfreq->previous_freq,
> +		get_freq_range(devfreq, &min_freq, &max_freq);
> +		polling_ms = devfreq->profile->polling_ms,
> +		mutex_unlock(&devfreq->lock);
> +
> +		seq_printf(s,
> +			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
> +			dev_name(devfreq->dev.parent),
> +			dev_name(&devfreq->dev),
> +			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
> +			devfreq->governor_name,
> +			polling_ms,
> +			cur_freq,
> +			min_freq,
> +			max_freq);
> +	}
> +
> +	mutex_unlock(&devfreq_list_lock);
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
> +
>  static int __init devfreq_init(void)
>  {
>  	devfreq_class = class_create(THIS_MODULE, "devfreq");
> @@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
>  	}
>  	devfreq_class->dev_groups = devfreq_groups;
>  
> +	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
> +	if (IS_ERR(devfreq_debugfs) && PTR_ERR(devfreq_debugfs) != -ENODEV) {
> +		pr_warn("%s: couldn't create debugfs dir\n", __FILE__);

If you'll take a look at [1], you may notice that it could fail only in
a single place in the code and in that case the error message is already
printed.

[1] https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L543

> +	} else {
> +		debugfs_create_file("devfreq_summary", 0444,
> +				devfreq_debugfs, NULL,
> +				&devfreq_summary_fops);

If you'll you'll take a look at [2], you may notice notice that it
checks whether devfreq_debugfs IS_ERR [3] and then bails out.

[2] https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L432
[3] https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L316

Thus you could simply remove the above error handling, making code to
look cleaner.

^ permalink raw reply	[flat|nested] 7+ messages in thread
* [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
       [not found] <CGME20200114013826epcas1p23a4c6c39f043dd09d33d48541288c1bd@epcas1p2.samsung.com>
@ 2020-01-14  1:45 ` Chanwoo Choi
  2020-01-14  1:45   ` Dmitry Osipenko
  0 siblings, 1 reply; 7+ messages in thread
From: Chanwoo Choi @ 2020-01-14  1:45 UTC (permalink / raw)
  To: linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, digetx, bjorn.andersson, jcrouse, cw00.choi,
	chanwoo, myungjoo.ham, kyungmin.park

Add debugfs interface to provide debugging information of devfreq device.
It contains 'devfreq_summary' entry to show the summary of registered
devfreq devices as following and the additional debugfs file will be added.
- /sys/kernel/debug/devfreq/devfreq_summary

[Detailed description of each field of 'devfreq_summary' debugfs file]
- dev_name	: Device name of h/w.
- dev		: Device name made by devfreq core.
- parent_dev	: If devfreq device uses the passive governor,
		  show parent devfreq device name. Otherwise, show 'null'.
- governor	: Devfreq governor.
- polling_ms	: If devfreq device uses the simple_ondemand governor,
		  polling_ms is necessary for the period. (unit: millisecond)
- cur_freq_Hz	: Current Frequency (unit: Hz)
- old_freq_Hz	: Frequency before changing. (unit: Hz)
- new_freq_Hz	: Frequency after changed. (unit: Hz)

[For example on Exynos5422-based Odroid-XU3 board]
$ cat /sys/kernel/debug/devfreq/devfreq_summary
dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000

[lkp: Reported the build error]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes from v2:
- Show 'null' at 'parent_dev' field when governor of devfreq device
  is not passive
Changes from v1:
- Drop the patch about 'devfreq_transitions' debugfs file
- Modify from 'hz' to 'Hz'
- Edit the indentation of 'devfreq_summary' when show summary
- Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir

 drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 89260b17598f..c5ef2d194b1b 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/sched.h>
+#include <linux/debugfs.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -33,6 +34,7 @@
 #define HZ_PER_KHZ	1000
 
 static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
 
 /*
  * devfreq core provides delayed work based load monitoring helper
@@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
 };
 ATTRIBUTE_GROUPS(devfreq);
 
+/**
+ * devfreq_summary_show() - Show the summary of the devfreq devices
+ * @s:		seq_file instance to show the summary of devfreq devices
+ * @data:	not used
+ *
+ * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
+ * It helps that user can know the detailed information of the devfreq devices.
+ *
+ * Return 0 always because it shows the information without any data change.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+	struct devfreq *devfreq;
+	struct devfreq *p_devfreq = NULL;
+	unsigned long cur_freq, min_freq, max_freq;
+	unsigned int polling_ms;
+
+	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
+			"dev_name",
+			"dev",
+			"parent_dev",
+			"governor",
+			"polling_ms",
+			"cur_freq_Hz",
+			"min_freq_Hz",
+			"max_freq_Hz");
+	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
+			"------------------------------",
+			"----------",
+			"----------",
+			"---------------",
+			"----------",
+			"------------",
+			"------------",
+			"------------");
+
+	mutex_lock(&devfreq_list_lock);
+
+	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
+							DEVFREQ_NAME_LEN)) {
+			struct devfreq_passive_data *data = devfreq->data;
+
+			if (data)
+				p_devfreq = data->parent;
+		} else {
+			p_devfreq = NULL;
+		}
+
+		mutex_lock(&devfreq->lock);
+		cur_freq = devfreq->previous_freq,
+		get_freq_range(devfreq, &min_freq, &max_freq);
+		polling_ms = devfreq->profile->polling_ms,
+		mutex_unlock(&devfreq->lock);
+
+		seq_printf(s,
+			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
+			dev_name(devfreq->dev.parent),
+			dev_name(&devfreq->dev),
+			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
+			devfreq->governor_name,
+			polling_ms,
+			cur_freq,
+			min_freq,
+			max_freq);
+	}
+
+	mutex_unlock(&devfreq_list_lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
 static int __init devfreq_init(void)
 {
 	devfreq_class = class_create(THIS_MODULE, "devfreq");
@@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
 	}
 	devfreq_class->dev_groups = devfreq_groups;
 
+	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+	if (IS_ERR(devfreq_debugfs) && PTR_ERR(devfreq_debugfs) != -ENODEV) {
+		pr_warn("%s: couldn't create debugfs dir\n", __FILE__);
+	} else {
+		debugfs_create_file("devfreq_summary", 0444,
+				devfreq_debugfs, NULL,
+				&devfreq_summary_fops);
+	}
+
 	return 0;
 }
 subsys_initcall(devfreq_init);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
  2020-01-14  1:45   ` Dmitry Osipenko
@ 2020-01-14  2:23     ` Chanwoo Choi
  2020-01-14  2:51       ` Dmitry Osipenko
  0 siblings, 1 reply; 7+ messages in thread
From: Chanwoo Choi @ 2020-01-14  2:23 UTC (permalink / raw)
  To: Dmitry Osipenko, linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, bjorn.andersson, jcrouse, chanwoo,
	myungjoo.ham, kyungmin.park

On 1/14/20 10:45 AM, Dmitry Osipenko wrote:
> 14.01.2020 04:45, Chanwoo Choi пишет:
>> Add debugfs interface to provide debugging information of devfreq device.
>> It contains 'devfreq_summary' entry to show the summary of registered
>> devfreq devices as following and the additional debugfs file will be added.
>> - /sys/kernel/debug/devfreq/devfreq_summary
>>
>> [Detailed description of each field of 'devfreq_summary' debugfs file]
>> - dev_name	: Device name of h/w.
>> - dev		: Device name made by devfreq core.
>> - parent_dev	: If devfreq device uses the passive governor,
>> 		  show parent devfreq device name. Otherwise, show 'null'.
>> - governor	: Devfreq governor.
>> - polling_ms	: If devfreq device uses the simple_ondemand governor,
>> 		  polling_ms is necessary for the period. (unit: millisecond)
>> - cur_freq_Hz	: Current Frequency (unit: Hz)
>> - old_freq_Hz	: Frequency before changing. (unit: Hz)
>> - new_freq_Hz	: Frequency after changed. (unit: Hz)
>>
>> [For example on Exynos5422-based Odroid-XU3 board]
>> $ cat /sys/kernel/debug/devfreq/devfreq_summary
>> dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
>> ------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
>> 10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
>> soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
>> soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
>> soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
>> soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
>> soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
>> soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
>> soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
>> soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
>> soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
>> soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
>> soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
>> soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
>> soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
>> soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
>> soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
>> soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000
>>
>> [lkp: Reported the build error]
>> Reported-by: kbuild test robot <lkp@intel.com>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
>> Changes from v2:
>> - Show 'null' at 'parent_dev' field when governor of devfreq device
>>   is not passive
>> Changes from v1:
>> - Drop the patch about 'devfreq_transitions' debugfs file
>> - Modify from 'hz' to 'Hz'
>> - Edit the indentation of 'devfreq_summary' when show summary
>> - Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir
>>
>>  drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 84 insertions(+)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 89260b17598f..c5ef2d194b1b 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -10,6 +10,7 @@
>>  #include <linux/kernel.h>
>>  #include <linux/kmod.h>
>>  #include <linux/sched.h>
>> +#include <linux/debugfs.h>
>>  #include <linux/errno.h>
>>  #include <linux/err.h>
>>  #include <linux/init.h>
>> @@ -33,6 +34,7 @@
>>  #define HZ_PER_KHZ	1000
>>  
>>  static struct class *devfreq_class;
>> +static struct dentry *devfreq_debugfs;
>>  
>>  /*
>>   * devfreq core provides delayed work based load monitoring helper
>> @@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
>>  };
>>  ATTRIBUTE_GROUPS(devfreq);
>>  
>> +/**
>> + * devfreq_summary_show() - Show the summary of the devfreq devices
>> + * @s:		seq_file instance to show the summary of devfreq devices
>> + * @data:	not used
>> + *
>> + * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
>> + * It helps that user can know the detailed information of the devfreq devices.
>> + *
>> + * Return 0 always because it shows the information without any data change.
>> + */
>> +static int devfreq_summary_show(struct seq_file *s, void *data)
>> +{
>> +	struct devfreq *devfreq;
>> +	struct devfreq *p_devfreq = NULL;
>> +	unsigned long cur_freq, min_freq, max_freq;
>> +	unsigned int polling_ms;
>> +
>> +	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
>> +			"dev_name",
>> +			"dev",
>> +			"parent_dev",
>> +			"governor",
>> +			"polling_ms",
>> +			"cur_freq_Hz",
>> +			"min_freq_Hz",
>> +			"max_freq_Hz");
>> +	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
>> +			"------------------------------",
>> +			"----------",
>> +			"----------",
>> +			"---------------",
>> +			"----------",
>> +			"------------",
>> +			"------------",
>> +			"------------");
>> +
>> +	mutex_lock(&devfreq_list_lock);
>> +
>> +	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
>> +		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
>> +							DEVFREQ_NAME_LEN)) {
>> +			struct devfreq_passive_data *data = devfreq->data;
>> +
>> +			if (data)
>> +				p_devfreq = data->parent;
>> +		} else {
>> +			p_devfreq = NULL;
>> +		}
>> +
>> +		mutex_lock(&devfreq->lock);
>> +		cur_freq = devfreq->previous_freq,
>> +		get_freq_range(devfreq, &min_freq, &max_freq);
>> +		polling_ms = devfreq->profile->polling_ms,
>> +		mutex_unlock(&devfreq->lock);
>> +
>> +		seq_printf(s,
>> +			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
>> +			dev_name(devfreq->dev.parent),
>> +			dev_name(&devfreq->dev),
>> +			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
>> +			devfreq->governor_name,
>> +			polling_ms,
>> +			cur_freq,
>> +			min_freq,
>> +			max_freq);
>> +	}
>> +
>> +	mutex_unlock(&devfreq_list_lock);
>> +
>> +	return 0;
>> +}
>> +DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
>> +
>>  static int __init devfreq_init(void)
>>  {
>>  	devfreq_class = class_create(THIS_MODULE, "devfreq");
>> @@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
>>  	}
>>  	devfreq_class->dev_groups = devfreq_groups;
>>  
>> +	
> If you'll you'll take a look at [2], you may notice notice that it
> checks whether devfreq_debugfs IS_ERR [3] and then bails out.
> 
> [2] https://protect2.fireeye.com/url?k=a5047d02-f8ca7cd1-a505f64d-000babff317b-ed64c541cd573190&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L432
> [3] https://protect2.fireeye.com/url?k=0a43fffa-578dfe29-0a4274b5-000babff317b-1c1c1062bfaeb0fc&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L316
> 
> Thus you could simply remove the above error handling, making code to
> look cleaner.
> 
> 

OK. I'll modify it as following: Do you agree?

	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
	debugfs_create_file("devfreq_summary", 0444,
			devfreq_debugfs, NULL,
			&devfreq_summary_fops);


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
  2020-01-14  2:23     ` Chanwoo Choi
@ 2020-01-14  2:51       ` Dmitry Osipenko
  2020-01-14  4:02         ` Chanwoo Choi
  0 siblings, 1 reply; 7+ messages in thread
From: Dmitry Osipenko @ 2020-01-14  2:51 UTC (permalink / raw)
  To: Chanwoo Choi, linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, bjorn.andersson, jcrouse, chanwoo,
	myungjoo.ham, kyungmin.park

14.01.2020 05:23, Chanwoo Choi пишет:
> On 1/14/20 10:45 AM, Dmitry Osipenko wrote:
>> 14.01.2020 04:45, Chanwoo Choi пишет:
>>> Add debugfs interface to provide debugging information of devfreq device.
>>> It contains 'devfreq_summary' entry to show the summary of registered
>>> devfreq devices as following and the additional debugfs file will be added.
>>> - /sys/kernel/debug/devfreq/devfreq_summary
>>>
>>> [Detailed description of each field of 'devfreq_summary' debugfs file]
>>> - dev_name	: Device name of h/w.
>>> - dev		: Device name made by devfreq core.
>>> - parent_dev	: If devfreq device uses the passive governor,
>>> 		  show parent devfreq device name. Otherwise, show 'null'.
>>> - governor	: Devfreq governor.
>>> - polling_ms	: If devfreq device uses the simple_ondemand governor,
>>> 		  polling_ms is necessary for the period. (unit: millisecond)
>>> - cur_freq_Hz	: Current Frequency (unit: Hz)
>>> - old_freq_Hz	: Frequency before changing. (unit: Hz)
>>> - new_freq_Hz	: Frequency after changed. (unit: Hz)
>>>
>>> [For example on Exynos5422-based Odroid-XU3 board]
>>> $ cat /sys/kernel/debug/devfreq/devfreq_summary
>>> dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
>>> ------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
>>> 10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
>>> soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
>>> soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
>>> soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
>>> soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
>>> soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
>>> soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
>>> soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
>>> soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
>>> soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
>>> soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
>>> soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
>>> soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
>>> soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
>>> soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
>>> soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
>>> soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000
>>>
>>> [lkp: Reported the build error]
>>> Reported-by: kbuild test robot <lkp@intel.com>
>>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>>> ---
>>> Changes from v2:
>>> - Show 'null' at 'parent_dev' field when governor of devfreq device
>>>   is not passive
>>> Changes from v1:
>>> - Drop the patch about 'devfreq_transitions' debugfs file
>>> - Modify from 'hz' to 'Hz'
>>> - Edit the indentation of 'devfreq_summary' when show summary
>>> - Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir
>>>
>>>  drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 84 insertions(+)
>>>
>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>> index 89260b17598f..c5ef2d194b1b 100644
>>> --- a/drivers/devfreq/devfreq.c
>>> +++ b/drivers/devfreq/devfreq.c
>>> @@ -10,6 +10,7 @@
>>>  #include <linux/kernel.h>
>>>  #include <linux/kmod.h>
>>>  #include <linux/sched.h>
>>> +#include <linux/debugfs.h>
>>>  #include <linux/errno.h>
>>>  #include <linux/err.h>
>>>  #include <linux/init.h>
>>> @@ -33,6 +34,7 @@
>>>  #define HZ_PER_KHZ	1000
>>>  
>>>  static struct class *devfreq_class;
>>> +static struct dentry *devfreq_debugfs;
>>>  
>>>  /*
>>>   * devfreq core provides delayed work based load monitoring helper
>>> @@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
>>>  };
>>>  ATTRIBUTE_GROUPS(devfreq);
>>>  
>>> +/**
>>> + * devfreq_summary_show() - Show the summary of the devfreq devices
>>> + * @s:		seq_file instance to show the summary of devfreq devices
>>> + * @data:	not used
>>> + *
>>> + * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
>>> + * It helps that user can know the detailed information of the devfreq devices.
>>> + *
>>> + * Return 0 always because it shows the information without any data change.
>>> + */
>>> +static int devfreq_summary_show(struct seq_file *s, void *data)
>>> +{
>>> +	struct devfreq *devfreq;
>>> +	struct devfreq *p_devfreq = NULL;

Looks like there is no need to pre-initialize the p_devfreq, please see
below.

>>> +	unsigned long cur_freq, min_freq, max_freq;
>>> +	unsigned int polling_ms;
>>> +
>>> +	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
>>> +			"dev_name",
>>> +			"dev",
>>> +			"parent_dev",
>>> +			"governor",
>>> +			"polling_ms",
>>> +			"cur_freq_Hz",
>>> +			"min_freq_Hz",
>>> +			"max_freq_Hz");
>>> +	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
>>> +			"------------------------------",
>>> +			"----------",
>>> +			"----------",
>>> +			"---------------",
>>> +			"----------",
>>> +			"------------",
>>> +			"------------",
>>> +			"------------");
>>> +
>>> +	mutex_lock(&devfreq_list_lock);
>>> +
>>> +	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
>>> +		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
>>> +							DEVFREQ_NAME_LEN)) {
>>> +			struct devfreq_passive_data *data = devfreq->data;
>>> +
>>> +			if (data)
>>> +				p_devfreq = data->parent;

			else
				p_devfreq = NULL;

Otherwise p_devfreq will be reused from a previous devfreq device if
that device has the data->parent.

>>> +		} else {
>>> +			p_devfreq = NULL;
>>> +		}
>>> +
>>> +		mutex_lock(&devfreq->lock);
>>> +		cur_freq = devfreq->previous_freq,
>>> +		get_freq_range(devfreq, &min_freq, &max_freq);
>>> +		polling_ms = devfreq->profile->polling_ms,
>>> +		mutex_unlock(&devfreq->lock);
>>> +
>>> +		seq_printf(s,
>>> +			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
>>> +			dev_name(devfreq->dev.parent),
>>> +			dev_name(&devfreq->dev),
>>> +			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
>>> +			devfreq->governor_name,
>>> +			polling_ms,
>>> +			cur_freq,
>>> +			min_freq,
>>> +			max_freq);
>>> +	}
>>> +
>>> +	mutex_unlock(&devfreq_list_lock);
>>> +
>>> +	return 0;
>>> +}
>>> +DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
>>> +
>>>  static int __init devfreq_init(void)
>>>  {
>>>  	devfreq_class = class_create(THIS_MODULE, "devfreq");
>>> @@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
>>>  	}
>>>  	devfreq_class->dev_groups = devfreq_groups;
>>>  
>>> +	
>> If you'll you'll take a look at [2], you may notice notice that it
>> checks whether devfreq_debugfs IS_ERR [3] and then bails out.
>>
>> [2] https://protect2.fireeye.com/url?k=a5047d02-f8ca7cd1-a505f64d-000babff317b-ed64c541cd573190&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L432
>> [3] https://protect2.fireeye.com/url?k=0a43fffa-578dfe29-0a4274b5-000babff317b-1c1c1062bfaeb0fc&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L316
>>
>> Thus you could simply remove the above error handling, making code to
>> look cleaner.
>>
>>
> 
> OK. I'll modify it as following: Do you agree?

Looks good, thanks.

> 	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);

I'd also add a newline here, to ease reading of the code.

> 	debugfs_create_file("devfreq_summary", 0444,
> 			devfreq_debugfs, NULL,
> 			&devfreq_summary_fops);
> 
> 


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
  2020-01-14  2:51       ` Dmitry Osipenko
@ 2020-01-14  4:02         ` Chanwoo Choi
  2020-01-14  4:05           ` Chanwoo Choi
  0 siblings, 1 reply; 7+ messages in thread
From: Chanwoo Choi @ 2020-01-14  4:02 UTC (permalink / raw)
  To: Dmitry Osipenko, linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, bjorn.andersson, jcrouse, chanwoo,
	myungjoo.ham, kyungmin.park

On 1/14/20 11:51 AM, Dmitry Osipenko wrote:
> 14.01.2020 05:23, Chanwoo Choi пишет:
>> On 1/14/20 10:45 AM, Dmitry Osipenko wrote:
>>> 14.01.2020 04:45, Chanwoo Choi пишет:
>>>> Add debugfs interface to provide debugging information of devfreq device.
>>>> It contains 'devfreq_summary' entry to show the summary of registered
>>>> devfreq devices as following and the additional debugfs file will be added.
>>>> - /sys/kernel/debug/devfreq/devfreq_summary
>>>>
>>>> [Detailed description of each field of 'devfreq_summary' debugfs file]
>>>> - dev_name	: Device name of h/w.
>>>> - dev		: Device name made by devfreq core.
>>>> - parent_dev	: If devfreq device uses the passive governor,
>>>> 		  show parent devfreq device name. Otherwise, show 'null'.
>>>> - governor	: Devfreq governor.
>>>> - polling_ms	: If devfreq device uses the simple_ondemand governor,
>>>> 		  polling_ms is necessary for the period. (unit: millisecond)
>>>> - cur_freq_Hz	: Current Frequency (unit: Hz)
>>>> - old_freq_Hz	: Frequency before changing. (unit: Hz)
>>>> - new_freq_Hz	: Frequency after changed. (unit: Hz)
>>>>
>>>> [For example on Exynos5422-based Odroid-XU3 board]
>>>> $ cat /sys/kernel/debug/devfreq/devfreq_summary
>>>> dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
>>>> ------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
>>>> 10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
>>>> soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
>>>> soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
>>>> soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
>>>> soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
>>>> soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
>>>> soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
>>>> soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
>>>> soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
>>>> soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
>>>> soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
>>>> soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
>>>> soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
>>>> soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
>>>> soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
>>>> soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
>>>> soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000
>>>>
>>>> [lkp: Reported the build error]
>>>> Reported-by: kbuild test robot <lkp@intel.com>
>>>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>> ---
>>>> Changes from v2:
>>>> - Show 'null' at 'parent_dev' field when governor of devfreq device
>>>>   is not passive
>>>> Changes from v1:
>>>> - Drop the patch about 'devfreq_transitions' debugfs file
>>>> - Modify from 'hz' to 'Hz'
>>>> - Edit the indentation of 'devfreq_summary' when show summary
>>>> - Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir
>>>>
>>>>  drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
>>>>  1 file changed, 84 insertions(+)
>>>>
>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>> index 89260b17598f..c5ef2d194b1b 100644
>>>> --- a/drivers/devfreq/devfreq.c
>>>> +++ b/drivers/devfreq/devfreq.c
>>>> @@ -10,6 +10,7 @@
>>>>  #include <linux/kernel.h>
>>>>  #include <linux/kmod.h>
>>>>  #include <linux/sched.h>
>>>> +#include <linux/debugfs.h>
>>>>  #include <linux/errno.h>
>>>>  #include <linux/err.h>
>>>>  #include <linux/init.h>
>>>> @@ -33,6 +34,7 @@
>>>>  #define HZ_PER_KHZ	1000
>>>>  
>>>>  static struct class *devfreq_class;
>>>> +static struct dentry *devfreq_debugfs;
>>>>  
>>>>  /*
>>>>   * devfreq core provides delayed work based load monitoring helper
>>>> @@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
>>>>  };
>>>>  ATTRIBUTE_GROUPS(devfreq);
>>>>  
>>>> +/**
>>>> + * devfreq_summary_show() - Show the summary of the devfreq devices
>>>> + * @s:		seq_file instance to show the summary of devfreq devices
>>>> + * @data:	not used
>>>> + *
>>>> + * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
>>>> + * It helps that user can know the detailed information of the devfreq devices.
>>>> + *
>>>> + * Return 0 always because it shows the information without any data change.
>>>> + */
>>>> +static int devfreq_summary_show(struct seq_file *s, void *data)
>>>> +{
>>>> +	struct devfreq *devfreq;
>>>> +	struct devfreq *p_devfreq = NULL;
> 
> Looks like there is no need to pre-initialize the p_devfreq, please see
> below.
> 
>>>> +	unsigned long cur_freq, min_freq, max_freq;
>>>> +	unsigned int polling_ms;
>>>> +
>>>> +	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
>>>> +			"dev_name",
>>>> +			"dev",
>>>> +			"parent_dev",
>>>> +			"governor",
>>>> +			"polling_ms",
>>>> +			"cur_freq_Hz",
>>>> +			"min_freq_Hz",
>>>> +			"max_freq_Hz");
>>>> +	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
>>>> +			"------------------------------",
>>>> +			"----------",
>>>> +			"----------",
>>>> +			"---------------",
>>>> +			"----------",
>>>> +			"------------",
>>>> +			"------------",
>>>> +			"------------");
>>>> +
>>>> +	mutex_lock(&devfreq_list_lock);
>>>> +
>>>> +	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {

#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 

>>>> +		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
>>>> +							DEVFREQ_NAME_LEN)) {
>>>> +			struct devfreq_passive_data *data = devfreq->data;
>>>> +
>>>> +			if (data)
>>>> +				p_devfreq = data->parent;
> 
> 			else
> 				p_devfreq = NULL;
> 
> Otherwise p_devfreq will be reused from a previous devfreq device if
> that device has the data->parent.

This path has the problem. I'm missing that.

'struct devfreq_passive_data' is only defined
when CONFIG_DEVFREQ_GOV_PASSIVE is enabled.

In case of when CONFIG_DEVFREQ_GOV_PASSIVE is disabled,
p_devfreq should be initialized with NULL as following:
I'll modify this patch as following:

struct devfreq *p_devfreq = NULL;

#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 
	if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
		DEVFREQ_NAME_LEN)) {
		struct devfreq_passive_data *data = devfreq->data;
		if (data)
			p_devfreq = data->parent;
		else
			p_devfreq = NULL;
#endif


> 
>>>> +		} else {
>>>> +			p_devfreq = NULL;
>>>> +		}
>>>> +
>>>> +		mutex_lock(&devfreq->lock);
>>>> +		cur_freq = devfreq->previous_freq,
>>>> +		get_freq_range(devfreq, &min_freq, &max_freq);
>>>> +		polling_ms = devfreq->profile->polling_ms,
>>>> +		mutex_unlock(&devfreq->lock);
>>>> +
>>>> +		seq_printf(s,
>>>> +			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
>>>> +			dev_name(devfreq->dev.parent),
>>>> +			dev_name(&devfreq->dev),
>>>> +			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
>>>> +			devfreq->governor_name,
>>>> +			polling_ms,
>>>> +			cur_freq,
>>>> +			min_freq,
>>>> +			max_freq);
>>>> +	}
>>>> +
>>>> +	mutex_unlock(&devfreq_list_lock);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
>>>> +
>>>>  static int __init devfreq_init(void)
>>>>  {
>>>>  	devfreq_class = class_create(THIS_MODULE, "devfreq");
>>>> @@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
>>>>  	}
>>>>  	devfreq_class->dev_groups = devfreq_groups;
>>>>  
>>>> +	
>>> If you'll you'll take a look at [2], you may notice notice that it
>>> checks whether devfreq_debugfs IS_ERR [3] and then bails out.
>>>
>>> [2] https://protect2.fireeye.com/url?k=a5047d02-f8ca7cd1-a505f64d-000babff317b-ed64c541cd573190&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L432
>>> [3] https://protect2.fireeye.com/url?k=0a43fffa-578dfe29-0a4274b5-000babff317b-1c1c1062bfaeb0fc&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L316
>>>
>>> Thus you could simply remove the above error handling, making code to
>>> look cleaner.
>>>
>>>
>>
>> OK. I'll modify it as following: Do you agree?
> 
> Looks good, thanks.
> 
>> 	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
> 
> I'd also add a newline here, to ease reading of the code.

ok.

> 
>> 	debugfs_create_file("devfreq_summary", 0444,
>> 			devfreq_debugfs, NULL,
>> 			&devfreq_summary_fops);
>>
>>
> 
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
  2020-01-14  4:02         ` Chanwoo Choi
@ 2020-01-14  4:05           ` Chanwoo Choi
  0 siblings, 0 replies; 7+ messages in thread
From: Chanwoo Choi @ 2020-01-14  4:05 UTC (permalink / raw)
  To: Dmitry Osipenko, linux-pm, linux-kernel
  Cc: leonard.crestez, lukasz.luba, a.swigon, m.szyprowski,
	enric.balletbo, hl, bjorn.andersson, jcrouse, chanwoo,
	myungjoo.ham, kyungmin.park

On 1/14/20 1:02 PM, Chanwoo Choi wrote:
> On 1/14/20 11:51 AM, Dmitry Osipenko wrote:
>> 14.01.2020 05:23, Chanwoo Choi пишет:
>>> On 1/14/20 10:45 AM, Dmitry Osipenko wrote:
>>>> 14.01.2020 04:45, Chanwoo Choi пишет:
>>>>> Add debugfs interface to provide debugging information of devfreq device.
>>>>> It contains 'devfreq_summary' entry to show the summary of registered
>>>>> devfreq devices as following and the additional debugfs file will be added.
>>>>> - /sys/kernel/debug/devfreq/devfreq_summary
>>>>>
>>>>> [Detailed description of each field of 'devfreq_summary' debugfs file]
>>>>> - dev_name	: Device name of h/w.
>>>>> - dev		: Device name made by devfreq core.
>>>>> - parent_dev	: If devfreq device uses the passive governor,
>>>>> 		  show parent devfreq device name. Otherwise, show 'null'.
>>>>> - governor	: Devfreq governor.
>>>>> - polling_ms	: If devfreq device uses the simple_ondemand governor,
>>>>> 		  polling_ms is necessary for the period. (unit: millisecond)
>>>>> - cur_freq_Hz	: Current Frequency (unit: Hz)
>>>>> - old_freq_Hz	: Frequency before changing. (unit: Hz)
>>>>> - new_freq_Hz	: Frequency after changed. (unit: Hz)
>>>>>
>>>>> [For example on Exynos5422-based Odroid-XU3 board]
>>>>> $ cat /sys/kernel/debug/devfreq/devfreq_summary
>>>>> dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
>>>>> ------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
>>>>> 10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
>>>>> soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
>>>>> soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
>>>>> soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
>>>>> soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
>>>>> soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
>>>>> soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
>>>>> soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
>>>>> soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
>>>>> soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
>>>>> soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
>>>>> soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
>>>>> soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
>>>>> soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
>>>>> soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
>>>>> soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
>>>>> soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000
>>>>>
>>>>> [lkp: Reported the build error]
>>>>> Reported-by: kbuild test robot <lkp@intel.com>
>>>>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>>> ---
>>>>> Changes from v2:
>>>>> - Show 'null' at 'parent_dev' field when governor of devfreq device
>>>>>   is not passive
>>>>> Changes from v1:
>>>>> - Drop the patch about 'devfreq_transitions' debugfs file
>>>>> - Modify from 'hz' to 'Hz'
>>>>> - Edit the indentation of 'devfreq_summary' when show summary
>>>>> - Exchange sequence between PTR_ERR and IS_ERR when debugfs_create_dir
>>>>>
>>>>>  drivers/devfreq/devfreq.c | 84 +++++++++++++++++++++++++++++++++++++++
>>>>>  1 file changed, 84 insertions(+)
>>>>>
>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>> index 89260b17598f..c5ef2d194b1b 100644
>>>>> --- a/drivers/devfreq/devfreq.c
>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>> @@ -10,6 +10,7 @@
>>>>>  #include <linux/kernel.h>
>>>>>  #include <linux/kmod.h>
>>>>>  #include <linux/sched.h>
>>>>> +#include <linux/debugfs.h>
>>>>>  #include <linux/errno.h>
>>>>>  #include <linux/err.h>
>>>>>  #include <linux/init.h>
>>>>> @@ -33,6 +34,7 @@
>>>>>  #define HZ_PER_KHZ	1000
>>>>>  
>>>>>  static struct class *devfreq_class;
>>>>> +static struct dentry *devfreq_debugfs;
>>>>>  
>>>>>  /*
>>>>>   * devfreq core provides delayed work based load monitoring helper
>>>>> @@ -1643,6 +1645,79 @@ static struct attribute *devfreq_attrs[] = {
>>>>>  };
>>>>>  ATTRIBUTE_GROUPS(devfreq);
>>>>>  
>>>>> +/**
>>>>> + * devfreq_summary_show() - Show the summary of the devfreq devices
>>>>> + * @s:		seq_file instance to show the summary of devfreq devices
>>>>> + * @data:	not used
>>>>> + *
>>>>> + * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
>>>>> + * It helps that user can know the detailed information of the devfreq devices.
>>>>> + *
>>>>> + * Return 0 always because it shows the information without any data change.
>>>>> + */
>>>>> +static int devfreq_summary_show(struct seq_file *s, void *data)
>>>>> +{
>>>>> +	struct devfreq *devfreq;
>>>>> +	struct devfreq *p_devfreq = NULL;
>>
>> Looks like there is no need to pre-initialize the p_devfreq, please see
>> below.
>>
>>>>> +	unsigned long cur_freq, min_freq, max_freq;
>>>>> +	unsigned int polling_ms;
>>>>> +
>>>>> +	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
>>>>> +			"dev_name",
>>>>> +			"dev",
>>>>> +			"parent_dev",
>>>>> +			"governor",
>>>>> +			"polling_ms",
>>>>> +			"cur_freq_Hz",
>>>>> +			"min_freq_Hz",
>>>>> +			"max_freq_Hz");
>>>>> +	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
>>>>> +			"------------------------------",
>>>>> +			"----------",
>>>>> +			"----------",
>>>>> +			"---------------",
>>>>> +			"----------",
>>>>> +			"------------",
>>>>> +			"------------",
>>>>> +			"------------");
>>>>> +
>>>>> +	mutex_lock(&devfreq_list_lock);
>>>>> +
>>>>> +	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
> 
> #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 
> 
>>>>> +		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
>>>>> +							DEVFREQ_NAME_LEN)) {
>>>>> +			struct devfreq_passive_data *data = devfreq->data;
>>>>> +
>>>>> +			if (data)
>>>>> +				p_devfreq = data->parent;
>>
>> 			else
>> 				p_devfreq = NULL;
>>
>> Otherwise p_devfreq will be reused from a previous devfreq device if
>> that device has the data->parent.
> 
> This path has the problem. I'm missing that.
> 
> 'struct devfreq_passive_data' is only defined
> when CONFIG_DEVFREQ_GOV_PASSIVE is enabled.
> 
> In case of when CONFIG_DEVFREQ_GOV_PASSIVE is disabled,
> p_devfreq should be initialized with NULL as following:
> I'll modify this patch as following:
> 
> struct devfreq *p_devfreq = NULL;
> 
> #if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE) 
> 	if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
> 		DEVFREQ_NAME_LEN)) {
> 		struct devfreq_passive_data *data = devfreq->data;
> 		if (data)
> 			p_devfreq = data->parent;
> 		else
> 			p_devfreq = NULL;
> #endif
> 
> 
>>
>>>>> +		} else {
>>>>> +			p_devfreq = NULL;
>>>>> +		}
>>>>> +
>>>>> +		mutex_lock(&devfreq->lock);
>>>>> +		cur_freq = devfreq->previous_freq,
>>>>> +		get_freq_range(devfreq, &min_freq, &max_freq);
>>>>> +		polling_ms = devfreq->profile->polling_ms,
>>>>> +		mutex_unlock(&devfreq->lock);
>>>>> +
>>>>> +		seq_printf(s,
>>>>> +			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
>>>>> +			dev_name(devfreq->dev.parent),
>>>>> +			dev_name(&devfreq->dev),
>>>>> +			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
>>>>> +			devfreq->governor_name,
>>>>> +			polling_ms,
>>>>> +			cur_freq,
>>>>> +			min_freq,
>>>>> +			max_freq);
>>>>> +	}
>>>>> +
>>>>> +	mutex_unlock(&devfreq_list_lock);
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
>>>>> +
>>>>>  static int __init devfreq_init(void)
>>>>>  {
>>>>>  	devfreq_class = class_create(THIS_MODULE, "devfreq");
>>>>> @@ -1659,6 +1734,15 @@ static int __init devfreq_init(void)
>>>>>  	}
>>>>>  	devfreq_class->dev_groups = devfreq_groups;
>>>>>  
>>>>> +	
>>>> If you'll you'll take a look at [2], you may notice notice that it
>>>> checks whether devfreq_debugfs IS_ERR [3] and then bails out.
>>>>
>>>> [2] https://protect2.fireeye.com/url?k=a5047d02-f8ca7cd1-a505f64d-000babff317b-ed64c541cd573190&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L432
>>>> [3] https://protect2.fireeye.com/url?k=0a43fffa-578dfe29-0a4274b5-000babff317b-1c1c1062bfaeb0fc&u=https://elixir.bootlin.com/linux/v5.5-rc6/source/fs/debugfs/inode.c#L316
>>>>
>>>> Thus you could simply remove the above error handling, making code to
>>>> look cleaner.
>>>>
>>>>
>>>
>>> OK. I'll modify it as following: Do you agree?
>>
>> Looks good, thanks.
>>
>>> 	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
>>
>> I'd also add a newline here, to ease reading of the code.
> 
> ok.
> 
>>
>>> 	debugfs_create_file("devfreq_summary", 0444,
>>> 			devfreq_debugfs, NULL,
>>> 			&devfreq_summary_fops);

Because there is not checking of return value,
I think that it is more proper instead of adding the newline
between debugfs_create_dir and debugfs_create_file.

	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
	debugfs_create_file("devfreq_summary", 0444,
				devfreq_debugfs, NULL,
				&devfreq_summary_fops);

>>>
>>>
>>
>>
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

^ permalink raw reply	[flat|nested] 7+ messages in thread
* [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file
       [not found] <CGME20200107015549epcas1p28a8f26855da65790c13d843506a0b15e@epcas1p2.samsung.com>
@ 2020-01-07  2:02 ` Chanwoo Choi
  0 siblings, 0 replies; 7+ messages in thread
From: Chanwoo Choi @ 2020-01-07  2:02 UTC (permalink / raw)
  To: linux-pm, linux-kernel
  Cc: cw00.choi, chanwoo, myungjoo.ham, kyungmin.park, natechancellor

Add debugfs interface to provide debugging information of devfreq device.
It contains 'devfreq_summary' entry to show the summary of registered
devfreq devices as following and the additional debugfs file will be added.
- /sys/kernel/debug/devfreq/devfreq_summary

[For example on Exynos5422-based Odroid-XU3 board]
- In order to show the multiple governors on devfreq_summay result,
change the governor of devfreq0 from simple_ondemand to userspace.

$ cat /sys/kernel/debug/devfreq/devfreq_summary
dev_name                       dev        parent_dev governor        polling_ms cur_freq     min_freq     max_freq
------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
10c20000.memory-controller     devfreq0              userspace       0          165000000    165000000    825000000
soc:bus_wcore                  devfreq1              simple_ondemand 50         400000000    84000000     400000000
soc:bus_noc                    devfreq2   devfreq1   passive         0          100000000    67000000     100000000
soc:bus_fsys_apb               devfreq3   devfreq1   passive         0          200000000    100000000    200000000
soc:bus_fsys                   devfreq4   devfreq1   passive         0          200000000    100000000    200000000
soc:bus_fsys2                  devfreq5   devfreq1   passive         0          150000000    75000000     150000000
soc:bus_mfc                    devfreq6   devfreq1   passive         0          333000000    96000000     333000000
soc:bus_gen                    devfreq7   devfreq1   passive         0          267000000    89000000     267000000
soc:bus_peri                   devfreq8   devfreq1   passive         0          67000000     67000000     67000000
soc:bus_g2d                    devfreq9   devfreq1   passive         0          333000000    84000000     333000000
soc:bus_g2d_acp                devfreq10  devfreq1   passive         0          267000000    67000000     267000000
soc:bus_jpeg                   devfreq11  devfreq1   passive         0          300000000    75000000     300000000
soc:bus_jpeg_apb               devfreq12  devfreq1   passive         0          167000000    84000000     167000000
soc:bus_disp1_fimd             devfreq13  devfreq1   passive         0          200000000    120000000    200000000
soc:bus_disp1                  devfreq14  devfreq1   passive         0          300000000    120000000    300000000
soc:bus_gscl_scaler            devfreq15  devfreq1   passive         0          300000000    150000000    300000000
soc:bus_mscl                   devfreq16  devfreq1   passive         0          400000000    84000000     400000000

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes from v2:
- Add polling_ms field to show the polling interval when using simple_ondemand
- Init devfreq_debugfs variable by NULL if failed
- Rename variable name from parent_devfreq to p_devfreq

Changes from v1:
- Handle exception case when DEVFREQ_GOV_PASSIVE is unset.

 drivers/devfreq/devfreq.c | 79 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 254f11b31824..9b60f45415b9 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/sched.h>
+#include <linux/debugfs.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -33,6 +34,7 @@
 #define HZ_PER_KHZ	1000
 
 static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
 
 /*
  * devfreq core provides delayed work based load monitoring helper
@@ -1717,6 +1719,74 @@ static struct attribute *devfreq_attrs[] = {
 };
 ATTRIBUTE_GROUPS(devfreq);
 
+/**
+ * devfreq_summary_show() - Show the summary of the registered devfreq devices
+ *				via 'devfreq_summary' debugfs file.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+	struct devfreq *devfreq;
+	struct devfreq *p_devfreq = NULL;
+	unsigned long cur_freq, min_freq, max_freq;
+	unsigned int polling_ms;
+
+	seq_printf(s, "%-30s %-10s %-10s %-15s %-10s %-12s %-12s %-12s\n",
+			"dev_name",
+			"dev",
+			"parent_dev",
+			"governor",
+			"polling_ms",
+			"cur_freq",
+			"min_freq",
+			"max_freq");
+	seq_printf(s, "%-30s %-10s %-10s %-15s %-10s %-12s %-12s %-12s\n",
+			"------------------------------",
+			"----------",
+			"----------",
+			"---------------",
+			"----------",
+			"------------",
+			"------------",
+			"------------");
+
+	mutex_lock(&devfreq_list_lock);
+
+	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
+		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
+							DEVFREQ_NAME_LEN)) {
+			struct devfreq_passive_data *data = devfreq->data;
+
+			if (data)
+				p_devfreq = data->parent;
+		} else {
+			p_devfreq = NULL;
+		}
+#endif
+		mutex_lock(&devfreq->lock);
+		cur_freq = devfreq->previous_freq,
+		get_freq_range(devfreq, &min_freq, &max_freq);
+		polling_ms = devfreq->profile->polling_ms,
+		mutex_unlock(&devfreq->lock);
+
+		seq_printf(s,
+			"%-30s %-10s %-10s %-15s %-10d %-12ld %-12ld %-12ld\n",
+			dev_name(devfreq->dev.parent),
+			dev_name(&devfreq->dev),
+			p_devfreq ? dev_name(&p_devfreq->dev) : "",
+			devfreq->governor_name,
+			polling_ms,
+			cur_freq,
+			min_freq,
+			max_freq);
+	}
+
+	mutex_unlock(&devfreq_list_lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
 static int __init devfreq_init(void)
 {
 	devfreq_class = class_create(THIS_MODULE, "devfreq");
@@ -1733,6 +1803,15 @@ static int __init devfreq_init(void)
 	}
 	devfreq_class->dev_groups = devfreq_groups;
 
+	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+	if (PTR_ERR(devfreq_debugfs) != -ENODEV && IS_ERR(devfreq_debugfs)) {
+		devfreq_debugfs = NULL;
+		pr_warn("%s: couldn't create debugfs dir\n", __FILE__);
+	} else {
+		debugfs_create_file("devfreq_summary", 0444, devfreq_debugfs,
+				NULL, &devfreq_summary_fops);
+	}
+
 	return 0;
 }
 subsys_initcall(devfreq_init);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-01-14  3:58 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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     [not found] <CGME20200114013826epcas1p23a4c6c39f043dd09d33d48541288c1bd@epcas1p2.samsung.com>
2020-01-14  1:45 ` [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file Chanwoo Choi
2020-01-14  1:45   ` Dmitry Osipenko
2020-01-14  2:23     ` Chanwoo Choi
2020-01-14  2:51       ` Dmitry Osipenko
2020-01-14  4:02         ` Chanwoo Choi
2020-01-14  4:05           ` Chanwoo Choi
     [not found] <CGME20200107015549epcas1p28a8f26855da65790c13d843506a0b15e@epcas1p2.samsung.com>
2020-01-07  2:02 ` Chanwoo Choi

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