[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v9 05/19] qspinlock: Optimize for smaller NR_CPUS
* Waiman Long <waiman.long@xxxxxx> wrote: > On 04/18/2014 03:46 AM, Ingo Molnar wrote: > >* Waiman Long<waiman.long@xxxxxx> wrote: > > > >>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. > >I suggest not renaming the function instead. > >try_clear_pending_set_locked() tells the intent in a clearer fashion. > > > >Thanks, > > > > Ingo > > I usually use the word "try" if there is a possibility of failure. > However, the function will always succeed, albeit by waiting a bit > in some cases. That is why I remove "try" from the name. Fair enough! Thanks, Ingo _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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