[PATCH tip/locking/core v9 1/6] locking/qspinlock: Use _acquire/_release versions of cmpxchg & xchg

This patch replaces the cmpxchg() and xchg() calls in the native qspinlock code with the more relaxed _acquire or _release versions of those calls to enable other architectures to adopt queued spinlocks with less memory barrier performance overhead. Signed-off-by: Waiman Long ---

[PATCH tip/locking/core v9 1/6] locking/qspinlock: Use _acquire/_release versions of cmpxchg & xchg

This patch replaces the cmpxchg() and xchg() calls in the native qspinlock code with the more relaxed _acquire or _release versions of those calls to enable other architectures to adopt queued spinlocks with less memory barrier performance overhead. Signed-off-by: Waiman Long