FIXME fix suggestions and question on fork semantics when tasks are moved

[matu3ba]

FIXME fix suggestions

1. Problem # FIXME: popen is slow...
   Solution: popen can be used with an array, which should not spawn a shell: https://docs.python.org/3.5/library/subprocess.html#replacing-functions-from-the-popen2-module

2. Problem # FIXME: very fragile
   Solution: Use counter index + argument class and let python handle the range checks. That way you can also offer nice stuff like saving cli args to file and loading from file + sanity check forwarded args etc.

I am not familiar with cpuset format etc yet, so I cant give advice on the other things.

3. More general improvements: Use, whenever possible, f-strings to improve performance and code clarity. For binary data unfortunately it is not possible, for utf8 encoded one it is.

Question on fork semantics when tasks are moved

https://man7.org/linux/man-pages/man7/cpuset.7.html does not mention that any race condition can occur during the move, but this website with a more in-depth tutorial claims this can occur

Note. There is a minor chance that a task forks during move and its child remains in the root cpuset. 

• 1. Do user space processes also have these problems? If yes, could 1.1 a low level api use strace to repeat and 1.2 is there a Kernel callback/event to listen for, if the cpuset has been successfully applied to a process after some write?
• 2. Does the Kernel provide a subsystem to group threads (ie names) and is there a user-space available API for aforementioned points 1.1 and 1.2 ?