[PATCH 25/27] rcu: Don't keep the tick for RCU while in userspace

If we are interrupting userspace, we don't need to keep the tick for RCU: quiescent states don't need to be reported because we soon run in userspace and local callbacks are handled by the nocb threads. CHECKME: Do the nocb threads actually handle the global grace period completion for local

[PATCH 25/27] rcu: Don't keep the tick for RCU while in userspace

If we are interrupting userspace, we don't need to keep the tick for RCU: quiescent states don't need to be reported because we soon run in userspace and local callbacks are handled by the nocb threads. CHECKME: Do the nocb threads actually handle the global grace period completion for local