From: Justin Forbes on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/560#note_51732...
c9f3401313a5089f100d7d1ef4b75cd7b49b2190 changes this a bit:
powerpc: Always enable queued spinlocks for 64s, disable for others
Queued spinlocks have shown to have good performance and fairness
properties even on smaller (2 socket) POWER systems. This selects
them
automatically for 64s. For other platforms they are de-selected, the
standard spinlock is far simpler and smaller code, and single chips
with a handful of cores is unlikely to show any improvement.
CONFIG_EXPERT still allows this to be changed, e.g., to help debug
performance or correctness issues.
If you wish to leave CONFIG_PPC_QUEUED_SPINLOCKS off, we will have to
enable CONFIG_EXPERT, and set anything else that it exposes. I have
changed pending to CONFIG_PPC_QUEUED_SPINLOCKS=y for now.