[$] Core scheduling

Kernel developers are used to having to defend their work when posting it
to the mailing lists, so when a longtime kernel developer describes their
own work as
'expensive and nasty', one tends to wonder what
is going on. The patch set in question is core
scheduling from Peter Zijlstra. It is intended to make simultaneous
multithreading (SMT) usable on systems where cache-based side channels are
a concern, but even its author is far from convinced that it should
actually become part of the kernel.