> It is hard to tell from just a diffstat how this implementation impacts
> the core. A similar diffstat for the driver implementation may
> help. "1300 insertions(+), 10 deletions(-)" does not seem like a lot of 
> core refactoring.

Here's the resctrl bits of Fenghua's diffstat (with the filename of the new
feature changed to avoid giving too much away):

 arch/x86/kernel/cpu/resctrl/core.c        |  39 +++-
 arch/x86/kernel/cpu/resctrl/newfeature.c  | 780 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/monitor.c     |   4 +-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 333 ++++++++++++++++++++++++++++-

Changes to core files are ~375 lines ... about 50% more than I added to core code
to provide a registration hook for this and many other drivers.  My driver registration
hooks will likely inflate by that much when the rough edges are smoothed.

-Tony