Messages in this thread | | | Date | Thu, 17 Apr 2014 17:49:02 -0400 | From | Waiman Long <> | Subject | Re: [PATCH v9 05/19] qspinlock: Optimize for smaller NR_CPUS |
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On 04/17/2014 11:58 AM, Peter Zijlstra wrote: > On Thu, Apr 17, 2014 at 11:03:57AM -0400, Waiman Long wrote: >> +static __always_inline void >> +clear_pending_set_locked(struct qspinlock *lock, u32 val) >> +{ >> + struct __qspinlock *l = (void *)lock; >> + >> + ACCESS_ONCE(l->locked_pending) = 1; >> +} >> @@ -157,8 +251,13 @@ static inline int trylock_pending(struct qspinlock *lock, u32 *pval) >> * we're pending, wait for the owner to go away. >> * >> * *,1,1 -> *,1,0 >> + * >> + * this wait loop must be a load-acquire such that we match the >> + * store-release that clears the locked bit and create lock >> + * sequentiality; this because not all try_clear_pending_set_locked() >> + * implementations imply full barriers. > You renamed the function referred in the above comment. >
Sorry, will fix the comments.
-Longman
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