* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 13 Jan 2009, Ingo Molnar wrote: > > > > And v8 is rock solid in all my testing - and i'll give v10 a similar > > workout as well. > > The differences between v8 and v10 are very fundamental, since v8 does > the spinning inside the spinlock'ed loop (the spinning itself is not > inside the spinlock, but all the "real action" is). So v8 not showing > problems doesn't really say much about v10 - totally different > algorithms that share only some of the support code. > > So even if many lines look the same, those code-lines aren't the really > interesting ones. The only really interesting once is really the > atomic_cmpxchg (outside spinlock) vs atomic_xchg (inside spinlock), and > those are almost diametrically opposite. yeah. What i thought they would be useful for are testing and experiments like this: " what if you switch the spinning to more fair by typing this in your current tree: git revert c10b491 " ... but that's a pretty narrow purpose. > > Would you prefer a single commit or is this kind of delta development > > history useful, with all the variants (at least the later, more > > promising ones) included? > > I'm not sure it makes sense to show the history here, especially as > there really were two different approaches, and while they share many > issues, they sure aren't equivalent nor are we really talking about any > evolution of the patch except in the sense of one being the kick-starter > for the alternative approach. > > What _can_ make sense is to commit some of the infrastructure helper > code separately, ie the lock ownership and preemption changes, since > those really are independent of the spinning code, and at least the > preemption thing is interesting and relevant even without it. ok, we'll improve the splitup. Ingo -- 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