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SubjectRe: [PATCH v3] locking/pvqspinlock: restore/set vcpu_hashed state after failing adaptive locking spinning
2016-07-14 22:52 GMT+08:00 Waiman Long <>:
> As pv_kick_node() is called immediately after designating the next node as
> the queue head, the chance of this racing is possible, but is not likely
> unless the lock holder vCPU gets preempted for a long time at that right
> moment. This change does not do any harm though, so I am OK with that.
> However, I do want you to add a comment about the possible race in the code
> as it isn't that obvious or likely.

How about something like:

* If the lock holder vCPU gets preempted for a long time, pv_kick_node will
* advance its state and hash the lock, restore/set the vcpu_hashed state to
* avoid the race.

Btw, do you think patch title should be improved, what do you like?

Wanpeng Li

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