Re: [tip:tracing/kmemtrace] rcutree: fix rcu_tree_trace.c data structure dependencies

[Ingo Molnar <mingo@elte.hu>]

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> > I think many of the data definitions (and the resulting include 
> > file dependencies) in include/linux/rcu*.h could move into 
> > kernel/rcu*.h and be privatized that way. 'struct rcu_state' 
> > would be an example.
> > 
> > Agreed?
> 
> In principle, yes.  In practice, my attempts to make headway in 
> this direction have usually collided with the desire to inline 
> some of the functions that appear on fastpaths, so I would prefer 
> caution when moving in this direction, especially given my 
> treercu-related todos, to which "speeding up synchronize_rcu()" 
> just got added.

I think there's a solution, for example the quiescent-state inlines 
could still be offered in a kernel/rcupdate_internals.h header to be 
included by kernel/softirq.c et al directly.

Otherwise ... i think it generally is not worth the trouble to put 
huge data types into common headers just to be able to inline into a 
small number of callsites.

	Ingo