On Thu, 2009-01-08 at 11:13 -0800, Linus Torvalds wrote: > > On Thu, 8 Jan 2009, Chris Mason wrote: > > > > It is less fair though, the 50 proc parallel creates had a much bigger > > span between the first and last proc's exit time. This isn't a huge > > shock, I think it shows the hot path is closer to a real spin lock. > > Actually, the real spin locks are now fair. We use ticket locks on x86. > We _could_ certainly aim for using ticket locks for mutexes too, that > might be quite nice. Not really, ticket locks cannot handle a spinner going away - and we need that here. I've googled around a bit and MCS locks (http://www.cs.rice.edu/~johnmc/papers/asplos91.pdf) look like a viable way to gain fairness in our situation. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
