Re: [PATCH 4/4] qspinlock for x86: smp_mb__after_spin_lock() is free

On Sun, Aug 28, 2016 at 01:56:16PM +0200, Manfred Spraul wrote: > For x86 qspinlocks, no additional memory barrier is required in > smp_mb__after_spin_lock: > > Theoretically, for qspinlock we could define two barriers: > - smp_mb__after_spin_lock: Free for x86, not free for powerpc > - smp_mb__be

[PATCH 4/4] qspinlock for x86: smp_mb__after_spin_lock() is free

For x86 qspinlocks, no additional memory barrier is required in smp_mb__after_spin_lock: Theoretically, for qspinlock we could define two barriers: - smp_mb__after_spin_lock: Free for x86, not free for powerpc - smp_mb__between_spin_lock_and_spin_unlock_wait(): Free for all archs, see queu