On Thu, Jan 15, 2009 at 10:16:53AM -0800, Linus Torvalds wrote: > > > On Thu, 15 Jan 2009, Ingo Molnar wrote: > > > > btw., i think spin-mutexes have a design advantage here: in a lot of code > > areas it's quite difficult to use spinlocks - cannot allocate memory, > > cannot call any code that can sporadically block (but does not _normally_ > > block), etc. > > > > With mutexes those atomicity constraints go away - and the performance > > profile should now be quite close to that of spinlocks as well. > > Umm. Except if you wrote the code nicely and used spinlocks, you wouldn't > hold the lock over all those unnecessary and complex operations. > > IOW, if you do pre-allocation instead of holding a lock over the > allocation, you win. So yes, spin-mutexes makes it easier to write the > code, but it also makes it easier to just plain be lazy. Yeah, I agree often it is harder to get the locking right but you end up with a better result. With mutexes, on the off chance you do have t oblock while holding the lock, performance and latency of other threads will tank. -- 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
