verifying where 'kworker/n:n' (in ps -aux) is invoked from - linux-kernel

Question

In the result of 'ps -aux', I couldn't find how to verify that 'kworker/...' are created from and what module/functions are related to it.
Please let me know how I find out kworkers are from with pid or else.
I've try to check files in /proc, nothing is shown about this.
$ ps -aux | grep kworker
root 15 0.0 0.0 0 0 ? S Aug12 0:00 [kworker/1:0]
root 16 0.0 0.0 0 0 ? S< Aug12 0:00 [kworker/1:0H]
root 85 0.0 0.0 0 0 ? S< Aug12 0:09 [kworker/0:1H]
root 3562 0.0 0.0 0 0 ? S< Aug12 0:00 [kworker/0:2H]
root 5578 0.0 0.0 0 0 ? S 11:13 0:01 [kworker/0:0]
root 5579 0.0 0.0 0 0 ? S 11:13 0:00 [kworker/u4:1]
root 8789 0.1 0.0 0 0 ? S 12:19 0:10 [kworker/0:2]
root 30236 0.0 0.0 0 0 ? S 08:39 0:01 [kworker/u4:0]

Answer 1

A good solution for these kinds of problems that I'm familiar with is to use the perf tool (It's not always enabled by default and you may need to install perf on your device).
Step 1: Set perf to record workqueue events:
perf record -e 'workqueue:*' -ag -T
Step 2: Run it as long as you think you need to catch the event (10 seconds should be ok if this event is frequent enough, but you can let it run longer, depending on the available free space you have left on your device) and then stop it with Ctrl + C.
Step 3: Print the captured events (on Linux versions < 4.1 I think it should be -f and not -F):
perf script -F comm,pid,tid,time,event,trace
This will display something like this: 
task-name pid/tid timestamp event
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
turtle   9201/9201 1473.339166:  workqueue:workqueue_queue_work: work struct=0xef20d4c4 function=pm_runtime_work workqueue=0xef1cb600 req_cpu=8 cpu=1
turtle   9201/9201 1473.339176: workqueue:workqueue_activate_work: work struct 0xef20d4c4
kworker/0:3  24223/24223 1473.339221: workqueue:workqueue_execute_start: work struct 0xef20d4c4: function pm_runtime_work
kworker/0:3  24223/24223 1473.339248:  workqueue:workqueue_execute_end: work struct 0xef20d4c4
Step 4: Analyzing the table above:
In the first row, a task named turtle (pid 9201) is pushing the work pm_runtime_work to the workqueue.
In the third row, we can see that the kworker/0:3 (pid 24223) is executing that work.
Summary: Now back to your questions, we see that kworker/0:3 has been requested by turtle task to run the pm_runtime_work function.
Now, if you want to dig further, you'll have step into the code and see what the pm_runtime_work function does. Good luck !!!