Re: [PATCH] mm/mmu_notifier: Remove non_block_start/end() from notifier invocation

[Jason Gunthorpe]

On Wed, Aug 12, 2026 at 02:46:08PM +0100, David Woodhouse wrote:
> I hear you. I'm less sceptical, given the use case, but I'll certainly
> concede that the universe is known for inventing better idiots.
> 
> I'm certainly not averse to having a wrapper so that the read sections
> don't just srcu_read_lock() directly, but also get a sanity check
> (non_block_start? local_irq_save? what would it actually be? does it
> have to be different for the hardirq vs. process-context invocations?)
> for free.
> 
> Or instead of a GPC-specific wrapper, do we make it a first-class SRCU
> citizen, SRCU_READ_FLAVOR_ATOMIC? If it disables preemption, we'd know
> that lock+unlock must happen on the *same* CPU, which could potentially
> simplify my new try_synchronize_srcu() and/or allow for a *spinning*
> grace period if we really do want that (although I'm unconvinced; it's
> *latency* we care about here, and punting to the WQ when we *already*
> have to wait is fair enough).

These all seem like good ideas, then you don't need to touch the
notifiers..

Jason