Re: [RFC PATCH 00/12] RCU pseudo-transactions

[Paul E. McKenney]

On Tue, Nov 10, 2026 at 10:49:03AM -0800, David Woodhouse wrote:
> On Mon, 2026-11-09 at 17:34 -0800, Paul E. McKenney wrote:
> > > Could the atomic flavor count its readers as srcu_read_lock_nmisafe()
> > > does? Then a reader could also enter from NMI. The code I have for the
> > > next version keeps one counter per NMI nesting level for this. With
> > > SRCU, the sums of locks and unlocks handle the nesting already.
> > 
> > The other user that I know of is David Woodhouse, now CCed.
> > 
> > David, would you be OK with srcu_read_lock_atomic() using NMI-safe
> > counters, similar to __srcu_read_lock_fast()?
> 
> I can't see any reason why I should object to that, as long as the
> synchronize_srcu_atomic() stays in the 4-16µs bracket which was our
> major criterion for this approach.

Then full speed ahead!  ;-)

> I'm still iterating on the KVM GPC use case¹, as sashiko-bot keeps
> finding things that my own local sashiko runs don't. 
> 
> ¹ https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/gpc-srcu-v3

I know that feeling...

							Thanx, Paul