Re: [PATCH 1/4] nmi_watchdog: use a boolean config flag forcompiling

[Cyrill Gorcunov]

On Mon, Feb 15, 2010 at 12:51:06PM -0500, Don Zickus wrote:
> On Sun, Feb 14, 2010 at 05:59:41PM +0100, Ingo Molnar wrote:
> > 
> > i'm still getting build failures:
> > 
> > arch/x86/built-in.o: In function `arch_trigger_all_cpu_backtrace':
> > (.text+0x151f5): undefined reference to `apic'
> > 
> > config attached.
> 
> Hmm, I can't get the config to match up properly when I run 'make
> oldconfig', even though I am using the HEAD of perf/nmi.  I took the
> defaults anyway and used 'ARCH=i386 make all' but couldn't reproduce your
> build failure.
> 
> Looking through the code, is there ever case where 'apic' is undefined?
> The arch_trigger_all_cpu_backtrace should match identically to the old nmi
> code, so I am stuck on how to fix this.
> 
> Thoughts?
> 

It looks familiar to one problem with HW breakpoints "Kconfig select"
issue Frederic fixed once not that long ago, if I recall correctly.

So due to select we choose to compile hw_nmi.c, but CONFIG_LOCAL_APIC
(or APIC on UP) is turned off. So apic.c is not compiled. And at stage
of linking we get unresolved symbol.

I don't remember the details how Frederic fixed HW breakpoints "select"
issue, CC'ed :) But you may google to find it out.

> Cheers,
> Don
> 

n.b.: i remember about p4 pmu, still out of time :(

	-- Cyrill
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