Messages in this thread | | | Date | Tue, 27 Aug 2013 15:53:10 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH RFC v2 1/2] qspinlock: Introducing a 4-byte queue spinlock implementation |
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On Tue, Aug 27, 2013 at 09:14:36AM -0400, Steven Rostedt wrote:
> I just had this conversation with Paul McKenney. Should there be a > smp_mb_after_spin_unlock()?
Depends on the benefits I suppose :-) Oleg and Linus did recently add smp_mb__before_spinlock();
> Although we blew it off as adding too many extensions to smp_mb(). But > it may be better than reimplementing something as complex as a lock.
Locks should be as light weight as possible and never implement anything heavier than the ACQUISITION / RELEASE barriers if at all possible. We should certainly not re-implement spinlocks just to get full barriers out of them, that's crazy.
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