Re: [PATCH v3 08/22] rcu,tracing: Create trace_rcu_{enter,exit}()

Steven Rostedt
2020-02-19T16:15:37Z

On Wed, 19 Feb 2020 16:58:28 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Feb 19, 2020 at 10:49:03AM -0500, Steven Rostedt wrote:
> > On Wed, 19 Feb 2020 15:47:32 +0100
> > Peter Zijlstra <peterz@infradead.org> wrote:
>
> > > These helpers are macros because of header-hell; they're placed here
> > > because of the proximity to nmi_{enter,exit{().
>
> ^^^^

Bah I can't read, because I even went looking for this!

>
> > > +#define trace_rcu_enter() \
> > > +({ \
> > > + unsigned long state = 0; \
> > > + if (!rcu_is_watching()) { \
> > > + rcu_irq_enter_irqsave(); \
> > > + state = 1; \
> > > + } \
> > > + state; \
> > > +})
> > > +
> > > +#define trace_rcu_exit(state) \
> > > +do { \
> > > + if (state) \
> > > + rcu_irq_exit_irqsave(); \
> > > +} while (0)
> > > +
> >
> > Is there a reason that these can't be static __always_inline functions?
>
> It can be done, but then we need fwd declarations of those RCU functions
> somewhere outside of rcupdate.h. It's all a bit of a mess.

Maybe this belongs in the rcupdate.h file then?

-- Steve