Re: [PATCH v2 rcu 04/18] rcu: Weaken ->dynticks accesses and updates

[Linus Torvalds]

On Wed, Jul 28, 2021 at 10:37 AM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> +/*
> + * Increment the current CPU's rcu_data structure's ->dynticks field
> + * with ordering.  Return the new value.
> + */
> +static noinstr unsigned long rcu_dynticks_inc(int incby)
> +{
> +       return arch_atomic_add_return(incby, this_cpu_ptr(&rcu_data.dynticks));
> +}

Maybe inline?

But more I reacted to how we sadly don't have percpu atomics. They'd
be fairly easy to add on x86, but I guess it's not a huge deal.

And hey, if this is pretty much the only place that would use them, I
guess that's not much of an issue.

             Linus