Re: [PATCH 1/10] Add generic helpers for arch IPI function calls

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

On Wed, May 07, 2008 at 10:42:52PM +0200, Jens Axboe wrote:
> On Mon, May 05 2008, Paul E. McKenney wrote:
> > OK.  The below still permits parallel smp_call_function()
> > and smp_call_function_mask() as well as permitting parallel
> > smp_call_function_single().  It prohibits the irq-disabled case.
> > 
> > Thoughts?
> 
> Sorry for the delayed response here. The below looks pretty good to me,
> though it'll require a few modifications to fixup smp_call_function()
> from irq disabled context.

Yep, easy fix, even if wait==1 needed.

> But that's doable, though I have to do a grep over the kernel to check
> everything (I remember CPU send_stop being one such path). Not a huge
> fan of such an interface, but hey...
> 
> Is everyone OK with going this route, initially at least? It's the
> lesser of all evils, I think.
> 
> > diff --git a/arch/Kconfig b/arch/Kconfig
> > index a5a0184..5ae9360 100644
> > --- a/arch/Kconfig
> > +++ b/arch/Kconfig
> > @@ -38,4 +38,4 @@ config HAVE_KRETPROBES
> >  	def_bool n
> >  
> >  config USE_GENERIC_SMP_HELPERS
> > -	def_bool n
> > +	def_bool y
> 
> This part puzzled me, why? We default to 'n' and let converted archs
> opt-in, so I don't get this part of your patch...

<red face>  I made that change to get it to compile, and forgot to
revert it when making the patch.  Please ignore that bit.

							Thanx, Paul