Messages in this thread |  | | Date | Sat, 10 Dec 2022 21:52:18 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [for-next][PATCH 13/25] x86/mm/kmmio: Use rcu_read_lock_sched_notrace() |
| |
On Sat, Dec 10, 2022 at 05:32:27PM -0500, Steven Rostedt wrote: > On Sat, 10 Dec 2022 13:34:12 -0800 > "Paul E. McKenney" <paulmck@kernel.org> wrote: > > > > I was going to remove it, but then I realized that it would be a functional > > > change, as from the comment above, it uses "preempt_enable_no_resched(), > > > which there is not a rcu_read_unlock_sched() variant. > > > > If this happens often enough, it might be worth adding something like > > rcu_read_unlock_sched_no_resched(), but we clearly are not there yet. > > Especially not with a name like that! ;-) > > Please don't ;-) > > This is only to handle the bizarre case that mmio tracing does. Remember, > this tracer is only for those that want to reverse engineer a binary > driver. It's not even SMP safe! When you enable it, it shuts down all but > one CPU. This is actually the reason I worked so hard to keep it working > with lockdep. The shutting down of CPUs has caught so many bugs in other > parts of the kernel! ;-) > > Thus, anything that mmio tracer does, is considered niche, and not > something to much care about.
Agreed, as I said, we are clearly not there yet.
Thanx, Paul
|  |