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

[Peter Zijlstra]

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@xxxxxxxxxxxxx> wrote:

> > These helpers are macros because of header-hell; they're placed here
> > because of the proximity to nmi_{enter,exit{().

^^^^

> > +#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.