Messages in this thread | | | Subject | Re: [PATCH 4/6] locking/rwsem: Avoid deceiving lock spinners | From | Davidlohr Bueso <> | Date | Thu, 29 Jan 2015 15:15:26 -0800 |
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On Thu, 2015-01-29 at 12:18 -0800, Jason Low wrote: > /* > - * We break out the loop above on need_resched() and when the > - * owner changed, which is a sign for heavy contention. Return > - * success only when lock->owner is NULL. > + * We break out the loop above on either need_resched(), when > + * the owner is not running, or when the lock owner changed. > + * Return success only when the lock owner changed. > */ > - return lock->owner == NULL; > + return lock->owner != owner; > }
Ideally we would refactor all this, along with getting rid of owner_running() at some point. It no longer makes sense to split up mutex_spin_on_owner() and we're doing duplicate owner checks. It would also be simpler than having to guess why we broke out of the loop, for example.
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