On Wed, 11 Apr 2007 19:23:26 +1000 Nick Piggin <[EMAIL PROTECTED]> wrote:
> But... that isn't there in mainline. Why is it in -mm? At any rate, that makes > it a no brainer to change. Seems to be related to lguest. Ask Rusty :) > > > > > As this external thing certainly is not doing the check itself, to be on > > the safe side we should enforce it in get_futex_key(). I agree with you : > > If we want to maximize performance, we could say : The check *must* be done > > by the caller. > > Well we _control_ the API, so let's make it as clean and performant as > possible > from the start. Take a look at do_futex(). Adding checks in callers just increase code size. I tried this got only bad results. This would speedup only the slow path (ie when some user code want to give us non aligned addrs) A single factorized check is cleaner and not slower, since we reduce icache pressure. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
