Re: [RFC,PATCH] RCU and CONFIG_PREEMPT_RT sane patch

["Paul E. McKenney" <paulmck@us.ibm.com>]

On Thu, Aug 04, 2005 at 07:49:33AM -0700, Paul E. McKenney wrote:
> On Thu, Aug 04, 2005 at 04:15:27PM +0200, Ingo Molnar wrote:
> > * Paul E. McKenney <paulmck@us.ibm.com> wrote:
> > 
> > Cool! I've merged your patch to the -52-12 version of the -RT patch. You 
> > can get it from the usual place:
> > 
> >   http://redhat.com/~mingo/realtime-preempt/
> > 
> > also, i've attached a port against 2.6.13-rc4. I have done this because 
> > the PREEMPT_RCU patch in my tree is applied before the core-PREEMPT_RT 
> > patch. I have fixed up the CONFIG_PREEMPT compilation branch and have 
> > removed your #error define - it built and booted fine on an UP box but 
> > there are no guarantees ...
> 
> Sounds great!!!  I will give it a thorough hammering in both the
> CONFIG_PREEMPT and CONFIG_PREEMPT_RT environments.

A couple of minor things thus far:

o	I get a linker error from V0.7.52-12:

	net/built-in.o(.init.text+0x898): In function `sock_aio_read':
	include/net/sock.h:625: undefined reference to `__you_cannot_kmalloc_that_much'

	This is not making much sense to me, since line 625 of sock.h
	is a small function with a container_of() as its only statement.
	The other other kmalloc() I can find in sock_aio_read() is
	allocating a "struct sock_iocb", which is certainly small enough
	for kmalloc() to handle.

	This may be a problem specific to the machine I compiled on,
	so am retrying on another.  Though that machine had absolutely
	no problem compiling and running V0.7.51-27...

	Enlightenment?

o	I messed up the #ifdefs for CONFIG_PREEMPT_RCU, CONFIG_RCU_STATS,
	and CONFIG_RCU_TORTURE_TEST so that it is not possible to build any
	of the following:

	1.	CONFIG_RCU_STATS without also CONFIG_RCU_TORTURE_TEST.

	2.	CONFIG_RCU_TORTURE_TEST without also CONFIG_RCU_STATS.

	3.	CONFIG_RCU_TORTURE_TEST without also CONFIG_PREEMPT_RCU.
		Which makes it tough to torture-test stock RCU.  ;-)

	Am checking out fixes for these, will post once I have untangled
	and tested.  Does not affect people who are not working directly
	on the RCU infrastructure itself.

							Thanx, Paul