Messages in this thread | | | Subject | Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file | From | Chanwoo Choi <> | Date | Tue, 14 Jan 2020 13:05:13 +0900 |
| |
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
| |