Re: [PATCH RFC v3 03/13] rcu-tasks: Add a Tasks RCU implementation for reader-marked trampolines

["Paul E. McKenney" <paulmck@xxxxxxxxxx>]

On Thu, Sep 17, 2026 at 12:25:40PM -0700, Paul E. McKenney wrote:
> On Thu, Sep 17, 2026 at 08:45:36PM +0200, Frederic Weisbecker wrote:
> > Le Thu, Sep 17, 2026 at 08:40:10AM -0700, Paul E. McKenney a écrit :
> > > > > Trampolines that transfer control to tracing code could supply the 
> > > > > needed
> > > > > cleanup call.  But last I checked, there were trampolines that 
> > > > > transferred
> > > > > directly back to the original code, with no opportunity for cleaning 
> > > > > up.
> > > > > 
> > > > > Or am I still missing a trick here?
> > > > 
> > > > You're right. So we'll indeed need to reuse the deferred qs points here.
> > > 
> > > Except this is getting a bit involved.
> > > 
> > > Don't get me wrong, if Josef is happy to take this on, far be it from me
> > > to stand in his way.  But if not, we should be willing to treat this
> > > optimization as a follow-on effort, whether by Josef or someone else.
> > 
> > Sure, I guess I can try the follow-on, especially if it leads to removing
> > all this RCU tasks black magic.
> 
> That sounds most excellent, thank you!

Ah, and in case anyone (especially Josef) is wondering, one big advantage
of the more elaborate approach is that it allowed the real-time guys to
avoid yet another source of IPIs messing with their latencies.

                                                        Thanx, Paul