Re: [RFC PATCH 4/6] Preempt-RCU: Implementation

[Roman Zippel <zippel@linux-m68k.org>]

Hi

On Thu, 28 Feb 2008, Paul E. McKenney wrote:

> > Why got this moved into init/Kconfig?
> 
> Because there are some arches that don't have kernel/Kconfig.preempt,
> its earlier home.  Therefore, putting it into kernel/Kconfig.preempt
> broke those arches' builds by supplying neither PREEMPT_RCU nor
> CLASSIC_RCU.
> 
> > Now it's somewhere in the root menu, not really belonging to anything.
> 
> Do you have a suggested location?
> 
> > Also why is this a choice? Are more RCU types planned?
> 
> I don't expect additional drop-in replacements for RCU, though people
> are certainly free to experiment if they wish.  It is a choice because
> this gives people a very clear idea of the two options and because
> it makes the implementation a bit cleaner.

I'd suggest to move PREEMPT_RCU back to Kconfig.preempt and if you really 
need the second symbol leave this behind (maybe with a comment):

config CLASSIC_RCU
	def_bool !PREEMPT_RCU

Once there are more options, we can still look for a better place...

Also could you please add a proper dependency to RCU_TRACE on PREEMPT_RCU, 
so that this condition isn't needed anymore:

ifeq ($(CONFIG_PREEMPT_RCU),y)
obj-$(CONFIG_RCU_TRACE) += rcupreempt_trace.o
endif

Thanks.

bye, Roman