[PATCH tip/locking/core v9 3/6] locking/pvqspinlock, x86: Optimize PV unlock code path

2015-10-30 Thread Waiman Long
The unlock function in queued spinlocks was optimized for better performance on bare metal systems at the expense of virtualized guests. For x86-64 systems, the unlock call needs to go through a PV_CALLEE_SAVE_REGS_THUNK() which saves and restores 8 64-bit registers before calling the real

[PATCH tip/locking/core v9 3/6] locking/pvqspinlock, x86: Optimize PV unlock code path

2015-10-30 Thread Waiman Long
The unlock function in queued spinlocks was optimized for better performance on bare metal systems at the expense of virtualized guests. For x86-64 systems, the unlock call needs to go through a PV_CALLEE_SAVE_REGS_THUNK() which saves and restores 8 64-bit registers before calling the real