Messages in this thread | | | Subject | Re: [PATCH v3] PM / devfreq: Add debugfs support with devfreq_summary file | From | Dmitry Osipenko <> | Date | Tue, 14 Jan 2020 05:51:31 +0300 |
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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); > >
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