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SubjectRe: [PATCH v3 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL
On 07/31/2015 04:39 AM, Peter Zijlstra wrote:
> On Wed, Jul 22, 2015 at 04:12:36PM -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.
> This needs to better spell out the race; my still sleeping brain doesn't
> want to co-operate and its generally better to spell out these things
> anyway.

Sure, I will add a comment to talk about the possible race.

Cheers,
Longman


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