On Thu, Jan 20, 2011 at 3:03 PM, Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Jan 20, 2011 at 08:20:00AM +1100, Nick Piggin wrote: >> On Thu, Jan 20, 2011 at 8:03 AM, Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: >> >> I don't know exactly how all programs use io_destroy -- of the small >> >> number that do, probably an even smaller number would care here. But I >> >> don't think it simplifies things enough to use synchronize_rcu for it. >> > >> > Above it sounded like you didn't think AIO should be using RCU at all. >> >> synchronize_rcu of course, not RCU (typo). > > I think that Nick is suggesting that call_rcu() be used instead. > Perhaps also very sparing use of synchronize_rcu_expedited(), which > is faster than synchronize_rcu(), but which which uses more CPU time. call_rcu() is the obvious alternative, yes. Basically, once we give in to synchronize_rcu() we're basically giving up. That's certainly a very good tradeoff for something like filesystem unregistration or module unload, it buys big simplifications in real fastpaths. But I just don't think it should be taken lightly. -- 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
