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

Greg KH
2021-06-14T17:01:01Z

On Mon, Jun 14, 2021 at 12:32:01PM -0400, Waiman Long wrote:
> On 6/14/21 11:52 AM, Greg KH wrote:
> > On Mon, Jun 14, 2021 at 11:23:06AM -0400, Waiman Long wrote:
> > > 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