From: Waiman Long on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/560#note_51841...
Using qspinlock is certainly a performance win for large systems with
many cpus. Even on 1-socket system, the performance should be comparable
with the current TAS spinlock. I will not suggest explicitly disabling
it. Switching between TAS spinlock and qspinlock does break kABI (at
least for the paravirtual version). If not, I would have backported it
to RHEL8.
Cheers,
Longman