Messages in this thread | | | Date | Wed, 23 Mar 2005 08:58:54 +0100 | From | Ingo Molnar <> | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07 |
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* Steven Rostedt <rostedt@goodmis.org> 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. > > Although you can't disable preemption for the duration of the > rcu_readlock, what about pinning the process to a CPU while it has the > lock. Would this help solve the migration issue?
yes, but that's rather gross. PREEMPT_BKL was opposed by Linus precisely because it used such a method - once that was fixed, PREEMPT_BKL got accepted. It also limits the execution flow quite much. I'd rather not do it if there's any other method.
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