On Wed, 2020-05-27 at 00:24 +0200, Greg KH wrote: > > Would you want random users to get the ability to hot unplug CPUs from your > > system? At unlimited quantity? I don't :). > > A random user, no, but one with admin rights, why not? They can do that > already today on your system, this isn't new. So I agree with you that a module parameter sucks. I disagree on the ioctl :) This is the kind of setup task that will probably end up being done by some shell script at boot time based on some config file. Being able to echo something in a sysfs file which will parse the standard-format CPU list using the existing kernel functions to turn that into a cpu_mask makes a lot more sense than having a binary interface via an ioctl which will require an extra userspace program for use by the admin for that one single task. So sysfs is my preference here. Another approach would be configfs, which would provide a more flexible interface to potentially create multiple "CPU sets" that could be given to different users or classes of users etc... but that might be pushing it, I don't know. Cheers, Ben.
