On Tue, Apr 12, 2016 at 08:02:17PM -0700, Jason Low wrote: > For qspinlocks on ARM64, we would like to use WFE instead > of purely spinning. Qspinlocks internally have lock > contenders spin on an MCS lock. > > Update arch_mcs_spin_lock_contended() such that it uses > the new smp_cond_load_acquire() so that ARM64 can also > override this spin loop with its own implementation using WFE. > > On x86, it can also cheaper to use this than spinning on > smp_load_acquire(). > > Signed-off-by: Jason Low <[email protected]>
FWIW, we just override arch_mcs_spin_lock_contended entirely for arch/arm/ and use wfe there so we could do the same for arm64 in mainline already. Will
