[PATCH v2 0/4] locking/qspinlock, x86: Improve determinism for x86

[Peter Zijlstra]

Back when Will did his qspinlock determinism patches, we were left with one
cmpxchg loop on x86 due to the use of atomic_fetch_or(). Will proposed a nifty
trick:

  http://lkml.kernel.org/r/20180409145409.GA9661@xxxxxxx

While that didn't quite work, this series implements that basic idea.

Changes since v1:

 - Adjusted comments in #2, wildea01
 - 'Simplified' GEN_*_RMWcc, peterz
 - Rewrote _the_ patch to use BTS, wildea01