search for: __atomic_and

...&slock->wait, value >> 8); if (ACCESS_ONCE(slock->lock)) { ... call lock_spinning hook ... } } /* * Set the lock bit & clear the halted+waiting bits */ if (cmpxchg(&slock->lock_wait, value, _QSPINLOCK_LOCKED) == value) return -1; /* Got the lock */ __atomic_and(&slock->lock_wait, ~QSPINLOCK_HALTED); The lock_spinning/unlock_lock code can probably be much simpler, because you do not need to keep a list of all spinning locks. Unlock_lock can just use the CPU number to wake up the right CPU. Paolo

On 02/27/2014 08:15 PM, Paolo Bonzini wrote: [...] >> But neither of the VCPUs being kicked here are halted -- they're either >> running or runnable (descheduled by the hypervisor). > > /me actually looks at Waiman's code... > > Right, this is really different from pvticketlocks, where the *unlock* > primitive wakes up a sleeping VCPU. It is more similar to PLE

On 02/27/2014 08:15 PM, Paolo Bonzini wrote: [...] >> But neither of the VCPUs being kicked here are halted -- they're either >> running or runnable (descheduled by the hypervisor). > > /me actually looks at Waiman's code... > > Right, this is really different from pvticketlocks, where the *unlock* > primitive wakes up a sleeping VCPU. It is more similar to PLE