Messages in this thread | | | Date | Tue, 22 May 2018 18:19:11 -0700 | From | Joel Fernandes <> | Subject | Re: Tasks RCU vs Preempt RCU |
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On Tue, May 22, 2018 at 10:47:11AM -0700, Paul E. McKenney wrote: > On Tue, May 22, 2018 at 01:27:00PM -0400, Steven Rostedt wrote: > > On Tue, 22 May 2018 09:09:49 -0700 > > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > > > > > Just for the record, if you guys realy want to take over Tasks RCU, > > > I have no objections. For one thing, I don't anticipate any other use > > > cases for it (famous last words!). But you break it, you buy it! ;-) > > > > It really matters how much of a burden is RCU_tasks to RCU itself? If > > it causes a lot of headache for you, and it prevents you from cleaning > > up RCU or making it better, then I would be happy to take it out of RCU > > and maintain it separately myself. But if that's not the case, I'm happy > > with keeping it within the RCU umbrella. Which brings me to the > > question of what motivation does Joel have to remove it? > > The burden on me from Tasks RCU has been quite light, so no need for a > change from my end. > > Over to you, Joel! ;-)
My motivation was I felt RCU-preempt already did the same thing (which I still believe it does) so its redundant. Although now I'm convinced from our earlier discussions that its not feasible to do an rcu_read_lock and rcu_read_unlock in trampoline code.
Sorry I didn't mean you should really nuke RCU-tasks if it has a purpose, but I was more trying to understand what its purpose was that RCU-preempt didn't solve. That's all.
And welcome back from Vacation Steve. I'm about to send v7 of my preempt/irq tracepoint patches so the timing seems great. I hope you will be able to take a look at them. thanks!
- Joel
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