On Fri, Aug 12, 2011 at 10:27 AM, Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > Or maybe I make rcu_cookie_gp_elapsed() take only one cookie and > compare it to the current cookie. This would save a bit of code in > the TINY cases: > > rcu_get_gp_cookie(&pagep->rcucookie); > . . . > > if (!rcu_cookie_gp_elapsed(&pagep->rcucookie)) > synchronize_rcu(); Agree this looks nicer that having the second cookie on the stack. As you said, this does not allow us to compare two past points in time, but I really don't see a use case for that. > How long would there normally be between recording the cookie and > checking for the need for a grace period? One disk access? One HZ? > Something else? I would expect >>10 seconds in the normal case ? I'm not sure how much lower this may get in adverse workloads. Andrea ? -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href