Re: [PATCH 4/4] driver core: Allow showing cpu as offline if not valid in cpuset context

On Mon, Jun 14, 2021 at 12:32:01PM -0400, Waiman Long wrote:

On 6/14/21 11:52 AM, Greg KH wrote:

quoted

On Mon, Jun 14, 2021 at 11:23:06AM -0400, Waiman Long wrote:

quoted

Make /sys/devices/system/cpu/cpu<n>/online file to show a cpu as
offline if it is not a valid cpu in a proper cpuset context when the
cpuset_bound_cpuinfo sysctl parameter is turned on.

This says _what_ you are doing, but I do not understand _why_ you want
to do this.

What is going to use this information?  And now you are showing more
files than you previously did, so what userspace tool is now going to
break?

One reason that is provided by the customer asking for this functionality is
because some applications use the number of cpu cores for licensing purpose.
Even though the applications are running in a container with a smaller set
of cpus, they may still charge as if all the cpus are available. They ended
up using a bind mount to mount over the cpuX/online file.

Great, then stick with the bind mount for foolish things like that.

There's no technical reason for doing this then, just marketing?

thanks,

greg k-h