On Fri, 2011-03-25 at 16:50 +0300, Andrey Kuzmin wrote: > On Fri, Mar 25, 2011 at 4:12 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > On Fri, 2011-03-25 at 14:13 +0300, Andrey Kuzmin wrote: > >> Turning try_lock into indefinitely spinning one breaks its semantics, > >> so deadlock is to be expected. But what's wrong in this scenario if > >> try_lock spins a bit before giving up? > > > > Because that will cause this scenario to spin that "little longer" > > always, and introduce latencies that did not exist before. Either the > > solution does not break this scenario, or it should not go in. > > Broken semantics and extra latency are two separate issues. If the > former is fixed, the latter is easily handled by introducing new > mutex_trylock_spin call that lets one either stick to existing > behavior (try/fail) or choose a new one where latency penalty is > justified by locking patterns. > For those wanting a more RT deterministic OS, I will argue against latency penalties. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
