Re: [PATCH v3 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL

[Davidlohr Bueso]

On Wed, 2015-07-22 at 16:12 -0400, Waiman Long wrote:
> The smp_store_release() is not a full barrier. In order to avoid missed
> wakeup, we may need to add memory barrier around locked and cpu state
> variables adding to complexity. As the chance of spurious wakeup is very
> low, it is easier and safer to just do an unconditional kick at unlock
> time.

Although I guess if SPIN_THRESHOLD is ever enlarged, the chances of
spurious wakeups would be greater.

> Signed-off-by: Waiman Long <Waiman.Long@xxxxxx>

Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>

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