Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07

Ingo Molnar
2005-03-24T05:35:28Z

* Paul E. McKenney <paulmck@us.ibm.com> wrote:

> Now, it is true that CPU#2 might record a quiescent state during this
> time, but this will have no effect because -all- CPUs must pass
> through a quiescent state before any callbacks will be invoked. Since
> CPU#1 is refusing to record a quiescent state, grace periods will be
> blocked for the full extent of task 1's RCU read-side critical
> section.

ok, great. So besides the barriers issue (and the long grace period time
issue), the current design is quite ok. And i think your original flip
pointers suggestion can be used to force synchronization.

Ingo