Re: [PATCH] perf/core: move all of the pmu devices into their own location

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Feb 04, 2025 at 11:41:38AM -0500, Vince Weaver wrote:
> On Tue, 4 Feb 2025, Greg Kroah-Hartman wrote:
> 
> > 
> > It seems that the majority of the perf code IS looking in the correct
> > place, just mem-events.c seemed wrong.
> 
> I hate to tell you, but other places in userspace are depending on the 
> current setup.  libpfm4, used by PAPI, is looking directly in /sys/devices 
> for pmus and will break with the changes you are planning.

Then that too needs to be fixed, sorry.  Again, devices can, and will,
move around in /sys/devices/ you can never hard-code any paths there.
Any userspace code must ALWAYS be able to handle that, that's a sysfs
requirement.

And do you have a link to the source for that code?  Good news is that
if the code is fixed in userspace, it will work for any kernel (old or
new).

thanks,

greg k-h