Re: [PATCH v2 0/7] srcu: NMI-safe atomic SRCU readers, and their irqsave forms

[Mathieu Desnoyers]

On 2026-11-11 14:02, David Woodhouse wrote:
> The latter claim is only true in __srcu_read_lock_fast()/_fast_updown()
> isn't it? Not in the atomic-SRCU. Unless we do something like this on
> top?

It is true for the atomic readers as well.  Without
CONFIG_NEED_SRCU_NMI_SAFE, include/linux/srcu.h defines
__srcu_read_lock_nmisafe() as an inline that calls __srcu_read_lock(),
and the same for unlock.  So x86 keeps this_cpu_inc() and smp_mb().
Your diff selects the same functions by hand.

Only the architectures that select NEED_SRCU_NMI_SAFE get the atomic
increments.

> I set a test running (*without* the above).

Thanks!

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com