On Sun, Dec 25, 2016 at 03:26:01PM -0500, Waiman Long wrote: > A number of cmpxchg calls in qspinlock_paravirt.h were replaced by more > relaxed versions to improve performance on architectures that use LL/SC.
Claim without numbers ;-) > > All the locking related cmpxchg's are replaced with the _acquire > variants: > - pv_queued_spin_steal_lock() > - trylock_clear_pending() So these seem to make sense in that they're in 'fast' paths.. > The cmpxchg's related to hashing are replaced by either by the _release > or the _relaxed variants. See the inline comment for details. But these not so much, we're going to put the vcpu to sleep, why does it make sense to 'optimize' the wait/kick stuff?
