On Wed, Jun 10, 2020 at 04:21:42PM -0700, Paul E. McKenney wrote: [...] > > > 8. To softirq 3. Either GP or CB kthread for the transitioning > > > CPU advances to next. > > > At this point, the no-CBs setup is fully shut down. > > > 9. To softirq 4. Transitioning code advances to next, > > > which is the first, "In softirq". > > > (This one -might- be unnecessary, but...) > > > > > > All transitions are of course with the ->nocb_lock held. > > > > > > When there is only one CPU during early boot near rcu_init() time, > > > the transition from "In softirq" to "No-CB" can remain be instantaneous. > > > > > > This has the advantage of not slowing things down just because there > > > is an RCU callback flood in progress. It also uses an explicit > > > protocol that should (give or take bugs) maintain full safety both > > > in protection of ->cblist and in dealing with RCU callback floods. > > > > > > Thoughts? > > > > Agreed. And I really like that it details the whole process in a very > > explicit way. > > > > Thanks! > > Glad you like it! And of course please adjust it as needed, up to and > including doing something completely different that works better. ;-)
Makes sense to me too, thanks! - Joel
