Re: [PATCH] x86: kill arch/x86/kernel/mpparse.c debugging printk.

[Rene Herman]

This is a multi-part message in MIME format.On 11-08-08 14:20, Ingo Molnar wrote:

> > From: Rene Herman <rene.herman@xxxxxxxxxxxx>
> > Date: Thu, 7 Aug 2008 01:50:35 +0200
> > Subject: [PATCH] x86: kill arch/x86/kernel/mpparse.c debugging printk.
> >
> > commit 11a62a056093a7f25f1595fbd8bd5f93559572b6 turns some formerly 
> > nopped debugging printks in arch/x86/kernel/mppparse.c into regular 
> > ones. The one at the top of smp_scan_config() in particular also 
> > prints on !CONFIG_SMP/CONFIG_X86_LOCAL_APIC kernels and UP machines 
> > without anything resembling MP tables which makes their lowly UP 
> > owners wonder...
> >
> > given that it was up to this point also not considered valuable 
> > user-level information, let's just kill that one.
>
> hm, i found it useful in the past in about 2-3 cases.
>
> How about a patch that makes the printout depend on apic=debug ? That 
> way the message can still be there in case of bugreports that somehow 
> deal with SMP or APIC bugs (without having to recompile the kernel).
>
> The way to make the printout depend on apic=debug/verbose is to do 
> something like this:
>
> 	apic_printk(APIC_VERBOSE, "Scan SMP from %p for %ld bytes.\n", bp, length);
>
> Would you mind to send a patch for that?

I wouldn't. Like this? This turns the printk's that used to be Dprintk's 
into apic_printk's.

I am myself only interested in the one at the top of smp_scan_config() 
(it made me think I had misconfigured something upon all of a sudden 
seeing SMP printk's on my UP machine on 2.6.27-rc) but I guess this is 
the more complete version.

One problem; on 32-bit, "apic=" is a __setup() param and isn't actually 
early enough for us here so this needs it turned into an early_param() 
(followup).

Rene.