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

Ingo Molnar
2005-03-23T09:03:59Z

* Peter Zijlstra <peter@programming.kicks-ass.net> wrote:

> > i think the 'migrate read-count' method is not adequate either, because
> > all callbacks queued within an RCU read section must be called after the
> > lock has been dropped - while with the migration method CPU#1 would be
> > free to process callbacks queued in the RCU read section still active on
> > CPU#2.
>
> how about keeping the rcu callback list in process context and only
> splice it to a global (per cpu) list on rcu_read_unlock?

hm, that would indeed solve this problem. It would also solve the grace
period problem: all callbacks in the global (per-CPU) list are
immediately processable. Paul?

Ingo